Display device and head-mounted display

Abstract

Provided is a highly reliable display device. A display device according to the present invention includes the following elements provided on a substrate: a first light emitting device; a first transistor electrically connected to the first light emitting device; a second light emitting device adjacent to the first light emitting device; a second transistor electrically connected to the second light emitting device; and a light blocking layer. The first light emitting device includes: a first pixel electrode; a first EL layer on the first pixel electrode; and a common electrode on the first EL layer. The second light emitting device includes: a second pixel electrode; a second EL layer on the second pixel electrode; and a common electrode on the second EL layer. In a cross-sectional view, the light blocking layer includes a region located between the first pixel electrode and the second pixel electrode, and the top face of the light blocking layer is lower than the top face of the first pixel electrode.

Description

Display device and head-mounted display

[0001] One embodiment of the present invention relates to a display device and a head-mounted display. Other embodiments of the present invention can include a display module, an electronic device, a semiconductor device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device (for example, a touch sensor) or an input / output device (for example, a touch panel), a driving method thereof, or a manufacturing method thereof.

[0002] Display devices are used in a variety of applications. Devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR) require high-brightness and high-resolution display devices.

[0003] As a display device, for example, a light-emitting device having a light-emitting device (also referred to as a light-emitting element) has been developed. A light-emitting device (also referred to as an EL device or an EL element) utilizing an electroluminescence (hereinafter referred to as an EL) phenomenon is controlled by a switching element such as a thin film transistor (hereinafter referred to as a TFT), and has features such as being easily thin and lightweight, being capable of high-speed response to an input signal, and being capable of being driven by a DC constant voltage power supply, and is therefore applied to a display device.

[0004] Patent Document 1 recognizes that the electrical characteristics of TFTs change when exposed to light, and discloses a configuration in a top-emission display device using organic EL elements in which a light-blocking material is used for the lower electrode of the organic EL element and the TFT is selectively arranged below the lower electrode.

[0005] Patent Document 2 discloses a display device for VR that uses an organic EL device (also called an organic EL element).

[0006] Patent Document 3 discloses a metal maskless (MML) structure, which is a device fabricated without using a metal mask or a fine metal mask (FMM), and further discloses a display device using the MML structure.

[0007] JP 2006-058814 A International Publication No. 2018 / 087625 International Publication No. 2022 / 162492

[0008] The configuration disclosed in Patent Document 1 can suppress light incident on the TFT from above, but the light is reflected or scattered by wiring, etc., so it cannot be said to be a sufficient configuration in terms of suppressing fluctuations in the electrical characteristics of the TFT, resulting in a display device with low reliability. Furthermore, Patent Document 2 has a configuration that includes a liquid crystal element in addition to a light-emitting element, making it difficult to reduce the weight.

[0009] Therefore, an object of the present invention is to provide a display device having a novel structure. Another object of the present invention is to provide a highly reliable display device. Another object of the present invention is to provide a lightweight display device.

[0010] The description of these problems does not preclude the existence of other problems. The present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the description of the specification, drawings, and claims.

[0011] One embodiment of the present invention that can solve the above-mentioned problems is a display device that includes, on a substrate, a first light-emitting device, a first transistor electrically connected to the first light-emitting device, a second light-emitting device adjacent to the first light-emitting device, a second transistor electrically connected to the second light-emitting device, and a light-shielding layer, wherein the first light-emitting device includes a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, and the second light-emitting device includes a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer, and in a cross-sectional view, the light-shielding layer has a region located between the first pixel electrode and the second pixel electrode, and an upper surface of the light-shielding layer is lower than an upper surface of the first pixel electrode.

[0012] Another aspect of the present invention is a display device comprising: a first light-emitting device, a first transistor electrically connected to the first light-emitting device, a second light-emitting device adjacent to the first light-emitting device, a second transistor electrically connected to the second light-emitting device, and a light-shielding layer, the first light-emitting device having a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer; the second light-emitting device having a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer; in a cross-sectional view, the light-shielding layer has a region located between the first pixel electrode and the second pixel electrode; and a height from the substrate to an upper surface of the light-shielding layer is lower than a height from the substrate to an upper surface of the first pixel electrode.

[0013] Another aspect of the present invention is a display device comprising: a first light-emitting device; a first transistor electrically connected to the first light-emitting device; a second light-emitting device adjacent to the first light-emitting device; a second transistor electrically connected to the second light-emitting device; and a light-shielding layer, the first light-emitting device having a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer; the second light-emitting device having a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer; in a cross-sectional view, the light-shielding layer has a region located between the first pixel electrode and the second pixel electrode, an upper surface of the light-shielding layer is lower than an upper surface of the first pixel electrode, and a thickness of the light-shielding layer is thicker than a thickness of the first pixel electrode.

[0014] Another aspect of the present invention is a display device comprising: a first light-emitting device, a first transistor electrically connected to the first light-emitting device, a second light-emitting device adjacent to the first light-emitting device, a second transistor electrically connected to the second light-emitting device; and a light-shielding layer, all disposed on a substrate; the first light-emitting device has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer; the second light-emitting device has a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer; in a cross-sectional view, the light-shielding layer has a region located between the first pixel electrode and the second pixel electrode; the height from the substrate to an upper surface of the light-shielding layer is lower than the height from the substrate to an upper surface of the first pixel electrode; and the film thickness of the light-shielding layer is greater than the film thickness of the first pixel electrode.

[0015] In the present invention, it is preferable that, in a cross-sectional view, the light-shielding layer has an area in contact with the side surface of the first pixel electrode, but does not have an area in contact with the top surface of the first pixel electrode.

[0016] In the present invention, the light-shielding layer preferably contains an organic material.

[0017] In the present invention, the light-shielding layer preferably has a transmittance of 50% or less for light having a wavelength of 300 nm or more and 550 nm or less.

[0018] In the present invention, it is preferable that the light-shielding layer has a region between the first pixel electrode and the second pixel electrode, the region having a thickness of 200 nm or more and 2000 nm or less.

[0019] In the present invention, the first pixel electrode preferably has a function of reflecting visible light.

[0020] In the present invention, the common electrode preferably has a function of transmitting visible light.

[0021] In the present invention, it is preferable that the side surface of the first EL layer has an area facing the side surface of the second EL layer in a cross-sectional view.

[0022] According to one embodiment or the like of the present invention, a display device having a novel structure can be provided. According to another embodiment of the present invention, a highly reliable display device can be provided. According to another embodiment of the present invention, a lightweight display device can be provided.

[0023] The description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims.

[0024] FIGS. 1A and 1B are top views showing an example of a display device. FIGS. 2A to 2C are cross-sectional views showing an example of a display device. FIGS. 3A to 3D are cross-sectional views showing an example of a display device. FIGS. 4A and 4B are cross-sectional views showing an example of a display device. FIG. 5 is a cross-sectional view showing an example of a display device. FIG. 6 is a cross-sectional view showing an example of a display device. FIG. 7 is a cross-sectional view showing an example of a display device. FIGS. 8A and 8B are cross-sectional views showing an example of a display device. FIGS. 9A to 9D are cross-sectional views showing an example of a display device. FIGS. 10A and 10B are cross-sectional views showing an example of a display device. FIGS. 11A and 11B are cross-sectional views showing an example of a display device. FIGS. 12A and 12B are cross-sectional views showing an example of a display device. FIGS. 13A and 13B are cross-sectional views showing an example of a display device. FIGS. 14A and 14B are cross-sectional views showing an example of a display device. FIG. 15 is a cross-sectional view showing an example of a display device. FIGS. 16A and 16B are cross-sectional views showing an example of a display device. FIG. 17 is a plan view showing an example of a display device. 18A to 18D show an example of a method for manufacturing a display device. FIGS. 19A to 19C show an example of a method for manufacturing a display device. FIGS. 20A to 20C show an example of a method for manufacturing a display device. FIGS. 21A to 21C show an example of a method for manufacturing a display device. FIGS. 22A to 22C show an example of a method for manufacturing a display device. FIGS. 23A to 23C show an example of a method for manufacturing a display device. FIGS. 24A and 24B show an example of a method for manufacturing a display device. FIG. 25 shows an example of a method for manufacturing a display device. FIG. 26 shows an example of a pixel circuit included in a display device. FIGS. 27A to 27G show an example of a pixel. FIGS. 28A to 28K show an example of a pixel. FIGS. 29A and 29B are perspective views showing an example of a display device. FIGS. 30A and 30B are cross-sectional views showing an example of a display device. FIG. 31 is a cross-sectional view showing an example of a display device. FIG. 32 is a cross-sectional view showing an example of a display device. 33A to 33F are diagrams showing configuration examples of a light-emitting device. FIGS. 34A and 34B are diagrams showing configuration examples of a light-receiving device. FIGS. 34C to 34E are diagrams showing configuration examples of a display device. FIGS. 35A to 35D are diagrams showing examples of electronic equipment.36A to 36F are diagrams showing an example of an electronic device, and Fig. 37A to Fig. 37G are diagrams showing an example of an electronic device.

[0025] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various changes can be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0026] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. Furthermore, when referring to similar functions, the same hatching pattern may be used and no particular reference numeral may be assigned.

[0027] For ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent the actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

[0028] In this specification, the ordinal numbers such as "first" and "second" are used for convenience and do not limit the number of components or the order of the components (for example, the order of processes or the order of stacking). Furthermore, the ordinal numbers assigned to components in one part of this specification may not match the ordinal numbers assigned to the same components in other parts of this specification or in the claims.

[0029] In this specification and drawings, when the same reference numeral is used for multiple elements, and particularly when it is necessary to distinguish between them, an identification symbol such as "_1", "[n]", or "[m, n]" may be added to the reference numeral. Furthermore, when explaining matters common to multiple elements to which an identification numeral is added, or when it is not necessary to distinguish between them, the elements may be described without the identification numeral.

[0030] In this specification and the like, the words "film" and "layer" can be interchangeable in some cases or depending on the situation. For example, the term "conductive layer" can be changed to the term "conductive film." Or, for example, the term "insulating film" can be changed to the term "insulating layer."

[0031] In this specification and the like, a transistor is a type of semiconductor element that can realize a function of amplifying a current or a voltage, a switching operation of controlling conduction or non-conduction, etc. The transistor in this specification includes an insulated gate field effect transistor (IGFET) and a thin film transistor (TFT).

[0032] In this specification, the functions of "source" and "drain" may be interchanged when transistors of different polarities are used or when the direction of current changes during circuit operation. Therefore, in this specification, the terms "source" and "drain" may be used interchangeably. Note that the names of the source and drain of a transistor may be appropriately changed depending on the situation, such as to be the source terminal and drain terminal, or the source electrode and drain electrode.

[0033] In this specification and the like, the terms "gate" and "back gate" can be used interchangeably. Therefore, in this specification and the like, the terms "gate" and "back gate" can be used interchangeably. Note that the names of the gate and back gate of a transistor can be appropriately changed to gate electrode and back gate electrode, etc., depending on the situation.

[0034] In this specification, "connection" includes, as an example, "electrical connection." Note that the term "electrical connection" is sometimes used to define the connection relationship between circuit elements as a physical entity. Furthermore, "electrical connection" includes "direct connection" and "indirect connection." "A and B are directly connected" means that A and B are connected without the intervention of a circuit element (e.g., a transistor, a switch, etc.; wiring is not considered a circuit element). On the other hand, "A and B are indirectly connected" means that A and B are connected via one or more circuit elements.

[0035] For example, assuming that a circuit including A and B is operating, if there is a time during the operation of the circuit when an electrical signal is exchanged or an interaction of electrical potential occurs between A and B, then it can be defined that "A and B are indirectly connected" as objects. Note that even if there is a time during the operation of the circuit when no electrical signal is exchanged or an interaction of electrical potential occurs between A and B, it can still be defined that "A and B are indirectly connected" as long as there is a time during the operation of the circuit when an electrical signal is exchanged or an interaction of electrical potential occurs between A and B.

[0036] An example of a case where "A and B are indirectly connected" is when A and B are connected via the source and drain of one or more transistors. On the other hand, an example of a case where it cannot be said that "A and B are indirectly connected" is when an insulator is present in the path from A to B. Specifically, there are cases where a capacitive element is connected between A and B, and cases where a gate insulating film of a transistor is present between A and B. Therefore, it cannot be said that "the gate (A) of a transistor and the source or drain (B) of the transistor are indirectly connected."

[0037] Another example of a case where it cannot be said that "A and B are indirectly connected" is when multiple transistors are connected via their sources and drains to the path from A to B, and a constant potential V is supplied to a node between one transistor and another transistor from a power supply, GND, etc.

[0038] In this specification, unless otherwise specified, the on-state current refers to the drain current (also referred to as Id) when a transistor is in an on state (also referred to as a conductive state). Unless otherwise specified, the on state refers to a state in which the gate-source voltage (also referred to as Vg or Vgs) is equal to or higher than a threshold voltage (also referred to as Vth) for an n-channel transistor, or a state in which the gate-source voltage is equal to or lower than the threshold voltage for a p-channel transistor.

[0039] In this specification and the like, unless otherwise specified, the off-state current refers to a leakage current between the source and drain when a transistor is in an off state (also referred to as a non-conducting state or a cut-off state). Unless otherwise specified, the off-state refers to a state in which the voltage between the gate and the source is lower than the threshold voltage in an n-channel transistor, and higher than the threshold voltage in a p-channel transistor.

[0040] In this specification, "parallel" refers to a state in which two straight lines are arranged at an angle of -10 degrees or more and 10 degrees or less. Therefore, it also includes cases in which the angle is -5 degrees or more and 5 degrees or less. Furthermore, "substantially parallel" refers to a state in which two straight lines are arranged at an angle of -30 degrees or more and 30 degrees or less. Furthermore, "perpendicular" refers to a state in which two straight lines are arranged at an angle of 80 degrees or more and 100 degrees or less. Therefore, it also includes cases in which the angle is 85 degrees or more and 95 degrees or less. Furthermore, "substantially perpendicular" refers to a state in which two straight lines are arranged at an angle of 60 degrees or more and 120 degrees or less.

[0041] In this specification, the phrase "top surface shapes that match or approximately match" refers to at least a portion of the contours of stacked layers overlapping. For example, this includes cases where the upper and lower layers are processed using the same mask pattern or a portion of the same mask pattern. However, strictly speaking, the contours may not overlap, and the upper layer may be located inside the lower layer, or outside the lower layer. In these cases, the phrase "top surface shapes that match or approximately match" may also be used. Furthermore, when the top surface shapes match or approximately match, it can also be said that "edges match or approximately match" or "edges are aligned or approximately aligned."

[0042] In this specification, a tapered shape refers to a shape in which at least a portion of the side surface of a structure is inclined relative to the substrate surface or the surface to be formed. For example, it is preferable to have a region in which the angle (also called the taper angle) between the inclined side surface and the substrate surface or the surface to be formed is less than 90 degrees. Note that the side surface of the structure, the substrate surface, and the surface to be formed do not necessarily have to be completely flat, and may be approximately planar with a slight curvature or approximately planar with a slight unevenness.

[0043] In this specification and the like, a step disconnection refers to a phenomenon in which a layer, a film, or an electrode is separated due to the shape of the surface on which it is formed (for example, a step or the like).

[0044] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in this specification, etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure. Because devices with an MML structure can be manufactured without using a metal mask, they can exceed the upper limit of resolution due to the alignment accuracy of the metal mask. Furthermore, devices with an MML structure can eliminate the need for equipment for manufacturing metal masks and a metal mask cleaning process. Furthermore, devices with an MML structure are suitable for mass production because they can keep manufacturing costs low.

[0045] In this specification and the like, a structure in which light-emitting layers are separately formed for light-emitting elements (also referred to as light-emitting devices) with different emission wavelengths is sometimes referred to as an SBS (Side By Side) structure. The SBS structure allows the materials and configuration to be optimized for each light-emitting element, thereby widening the range of material and configuration options and facilitating improvements in brightness and reliability.

[0046] In this specification and the like, holes or electrons may be referred to as "carriers." Specifically, a hole injection layer or an electron injection layer may be referred to as a "carrier injection layer," a hole transport layer or an electron transport layer may be referred to as a "carrier transport layer," and a hole block layer or an electron block layer may be referred to as a "carrier block layer." Note that the above-mentioned carrier injection layer, carrier transport layer, and carrier block layer may not be clearly distinguishable. Furthermore, one layer may have two or three functions among the carrier injection layer, carrier transport layer, and carrier block layer.

[0047] In this specification and the like, a light-emitting element has an EL layer between a pair of electrodes. The EL layer has at least a light-emitting layer. Here, examples of layers (also referred to as functional layers) included in the EL layer include a light-emitting layer, a carrier injection layer (a hole injection layer and an electron injection layer), a carrier transport layer (a hole transport layer and an electron transport layer), and a carrier block layer (a hole block layer and an electron block layer). In this specification and the like, a light-receiving element (also referred to as a light-receiving device) has at least an active layer that functions as a photoelectric conversion layer between a pair of electrodes. In this specification and the like, one of the pair of electrodes may be referred to as a pixel electrode, and the other as a common electrode.

[0048] In this specification and the like, a light-receiving device (also referred to as a light-receiving element) has at least an active layer that functions as a photoelectric conversion layer between a pair of electrodes.

[0049] In this specification, the term "island-like" refers to a state in which two or more layers made of the same material and formed in the same process are physically separated. For example, an island-like light-emitting layer refers to a state in which the light-emitting layer is physically separated from an adjacent light-emitting layer.

[0050] In this specification and the like, the mask layer is located above at least the light-emitting layer (more specifically, the layer that is processed into an island shape among the layers that constitute the EL layer) and has the function of protecting the light-emitting layer during the manufacturing process.

[0051] Embodiment 1 In this embodiment, a display device according to one embodiment of the present invention will be described with reference to FIGS. 1A to 17. FIG.

[0052] A display device according to one embodiment of the present invention includes a first light-emitting device, a first transistor electrically connected to the first light-emitting device, a second light-emitting device adjacent to the first light-emitting device, a second transistor electrically connected to the second light-emitting device, and a light-shielding layer on a substrate. The substrate is a substrate on which the light-emitting device, the transistor, and the like are mounted, and the material of the substrate is not limited in any way.

[0053] In the display device according to one aspect of the present invention, the first light-emitting device preferably has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, and the second light-emitting device preferably has a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer. In the display device according to one aspect of the present invention, the light-emitting devices preferably use organic EL elements.

[0054] The light-shielding layer included in the display device according to one embodiment of the present invention preferably has a region located between the first pixel electrode and the second pixel electrode in a cross-sectional view. The light-shielding layer can prevent light emitted from the first light-emitting device or the second light-emitting device from entering the first transistor and the second transistor. Note that the light includes emitted light reflected by wiring or the like (reflected light) and light scattered by wiring or the like (scattered light). Reflected light and scattered light may be collectively referred to as stray light. In other words, the light includes stray light. This can sufficiently prevent fluctuations in the electrical characteristics of the first transistor and the second transistor. The arrangement of the light-shielding layer is not particularly limited as long as it can prevent light from entering the first transistor and the second transistor.

[0055] In a display device according to one embodiment of the present invention, if the light-shielding layer contacts the upper surface of the first pixel electrode, the contact area between the first pixel electrode and the first EL layer may be reduced. This reduces the light-emitting area of ​​the first light-emitting device. Therefore, it is preferable to arrange the light-shielding layer so that it does not contact the upper surface of the first pixel electrode. For example, a configuration in which the upper surface of the first pixel electrode is higher than the upper surface of the light-shielding layer is preferable. In other words, it is preferable that the upper surface of the light-shielding layer is at the same level as or lower than the upper surface of the first pixel electrode. The reference plane at this position can be, for example, the surface on which the light-shielding layer is formed or the upper surface of the substrate. The first pixel electrode can be interpreted as the second pixel electrode, and it is preferable that the upper surface of the light-shielding layer is at the same level as or lower than the upper surface of the second pixel electrode.

[0056] In a display device according to one embodiment of the present invention, the height of the light-shielding layer is preferably lower than the height of the first pixel electrode. The reference plane for the height can be the surface on which the first pixel electrode is formed, the surface on which the light-shielding layer is formed, or the upper surface of the substrate. The height is the shortest distance from the reference plane. In other words, if the upper surface of the light-shielding layer is not flat, or if the upper surface of the first pixel electrode is not flat, the shortest distance is defined as the height. Note that the first pixel electrode can be read as the second pixel electrode, and even if the upper surface of the second pixel electrode is not flat, the shortest distance is defined as the height.

[0057] In the display device according to one embodiment of the present invention, the thickness of the light-shielding layer is preferably 200 nm or more and 2000 nm or less, and at least the light-shielding layer located between the first pixel electrode and the second pixel electrode preferably has a thickness of 200 nm or more and 2000 nm or less. As the thickness of the light-shielding layer increases, the light-shielding effect increases.

[0058] In the display device according to one embodiment of the present invention, a colored resin can be preferably used for the light-shielding layer, and the color can be red, brown, or black. Furthermore, the light-shielding layer can be configured by laminating a red resin and a green resin. A material used for a color filter can be used as the colored resin.

[0059] A display device according to one embodiment of the present invention preferably employs a top-emission system. The top-emission system is a system in which light is extracted from a common electrode. When a top-emission display device is used, the first pixel electrode preferably includes a conductive material that reflects visible light. The common electrode preferably includes a conductive material that transmits visible light. Note that the first pixel electrode can be read as a second pixel electrode, and when a top-emission display device is used, the second pixel electrode preferably includes a conductive material that reflects visible light.

[0060] In the top-emission type, the common electrode preferably functions as a semi-transmissive / semi-reflective electrode. A semi-transmissive / semi-reflective electrode is an electrode having a structure in which a transparent material and a reflective material are laminated. This allows the light-emitting device to have a micro-optical resonator (microcavity) structure, and light from the EL layer, particularly the light-emitting layer, resonates between the pixel electrode and the common electrode, thereby intensifying the light emitted from the light-emitting device. To achieve the microcavity structure, the light-emitting device may have an optical adjustment layer on the pixel electrode. It is preferable to set the thickness of the optical adjustment layer so as to obtain an optical path length that intensifies the light emitted from the light-emitting device.

[0061] A display device according to one embodiment of the present invention can employ a bottom emission system. The bottom emission system is a system in which light is extracted from pixel electrodes. In the case of a bottom emission display device, the pixel electrodes preferably include a conductive material that transmits visible light. In addition, in the case of using a bottom emission display device, the common electrode preferably includes a conductive material that reflects visible light.

[0062] In one embodiment of the present invention, a high-definition display device preferably has a light-emitting device with an MML structure. Adjacent light-emitting devices using the MML structure have a structure in which side surfaces of the EL layers face each other.

[0063] Head-mounted displays (also referred to as HMDs) are an example of devices for virtual reality, augmented reality, alternative reality, and mixed reality. A display device according to one embodiment of the present invention has a light-shielding layer positioned between a first pixel electrode and a second pixel electrode, thereby achieving sufficient contrast even without an element with a light-shielding function, such as a liquid crystal element. That is, the light-shielding layer not only suppresses light incidence on the transistor, but also enhances the contrast of the display device. Therefore, a lightweight display device can be achieved, making it preferable as a display device to be mounted in an HMD. An HMD has optical components, typically lenses, which attenuate the luminance of the display device, so improved luminance is desirable for the display device. Of course, improved luminance is also desirable for display devices not mounted in an HMD. Therefore, in a display device according to one embodiment of the present invention, the luminance of light emitted from the light-emitting device is 8000 cd / m ２ More than 20000cd / m ２ Below 10000 cd / m ２ More than 18000cd / m ２ It is preferable that the following is satisfied: In addition, the brightness of the display device mounted on the HMD is 12,000 cd / m ２ In a display device in which such luminance is emitted from a light-emitting device, the influence of stray light is large, and therefore it is important to suppress fluctuations in the electrical characteristics of the transistor by using a structure including a light-shielding layer.

[0064] [Typical Example] In this embodiment, a typical example of the display device will be described. Fig. 1A illustrates an example of a top view (also referred to as a plan view) of a display device 100 according to one embodiment of the present invention.

[0065] As shown in Figure 1A, the first light-emitting region seen in the top view is called subpixel 11R, the second light-emitting region is called subpixel 11G, and the third light-emitting region is called subpixel 11B. Subpixels 11R, 11G, and 11B are collectively called pixel 110. As shown in Figure 1A, a plurality of subpixels 11R, 11G, and 11B are regularly arranged. Figure 1A shows two rows and six columns of subpixels, which together form two rows and two columns of pixels 110.

[0066] To provide the first light-emitting region, the pixel circuit corresponding to the subpixel includes multiple transistors. The layout of the transistors does not need to fit within the outer edge of the subpixel in the top view, and they can be arranged outside the outer edge. For example, some or all of the multiple transistors corresponding to subpixel 11R can be located outside the outer edge of subpixel 11R. The transistors located outside the outer edge may be arranged in a position that overlaps with subpixel 11G or subpixel 11B shown in FIG. 1A.

[0067] 1A, the areas of the subpixels 11R, 11G, and 11B are shown as being equal, but the areas may be different from one another. The top surface shape of the subpixels may be, for example, a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, or a circle.

[0068] The region having the pixels 110 is called a pixel portion. The display device 100 also has a connection portion 140 located on the periphery or outer edge of the pixel portion. The connection portion 140 may also be called a cathode contact portion. FIG. 1A shows an example in which the connection portion 140 is located on one side of the pixel portion, but the location is not particularly limited. The connection portion 140 may be provided in at least one location on the upper, right, left, or lower side of the pixel portion when viewed from above, and may be provided, for example, so as to surround all four sides of the pixel portion. The top surface shape of the connection portion 140 may be strip-shaped, L-shaped, U-shaped, frame-shaped, or the like. The connection portion 140 may be singular or plural.

[0069] A stripe arrangement is applied to the pixel 110 shown in FIG. 1A . The subpixels 11R, 11G, and 11B each have a light-emitting device that emits a different light color. Examples of the subpixels 11R, 11G, and 11B include subpixels of three colors: red (R), green (G), and blue (B), and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). The number of types of subpixels is not limited to three and can be four or more. Examples of four subpixels include subpixels of four colors: R, G, B, and white (W), subpixels of R, G, B, and B, subpixels of R, G, B, and Y, and subpixels of R, G, B, and infrared (IR).

[0070] In this specification and the like, the row direction may be referred to as the X direction, and the column direction may be referred to as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly (see FIG. 1A ). FIG. 1A shows an example in which subpixels of different colors are arranged side by side in the X direction, and subpixels of the same color are arranged side by side in the Y direction.

[0071] Next, Figures 2A to 3D each show an example of a cross-sectional view of the display device 100. Figures 2A to 3D correspond to the cross-sectional views taken along X1-X2 in Figure 1A.

[0072] FIG. 2A shows light-emitting device 130R located in the first light-emitting region, light-emitting device 130G located in the second light-emitting region, and light-emitting device 130B located in the third light-emitting region. That is, display device 100 has light-emitting device 130R corresponding to subpixel 11R, light-emitting device 130G corresponding to subpixel 11G, and light-emitting device 130B corresponding to subpixel 11B. Any two selected from each light-emitting device correspond to the adjacent first light-emitting device and second light-emitting device. Light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B preferably have different emission colors, which can be selected from red, green, and blue. Of course, light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B may have the same emission color, with white being preferred. When white is used, a red color filter is placed at a position overlapping with light-emitting device 130R, a green color filter is placed at a position overlapping with light-emitting device 130G, and a blue color filter is placed at a position overlapping with light-emitting device 130B.

[0073] Light-emitting device 130R has pixel electrode 111R, EL layer 113R, and common electrode 115. Light-emitting device 130G has pixel electrode 111G, EL layer 113G, and common electrode 115. Light-emitting device 130B has pixel electrode 111B, EL layer 113R, and common electrode 115. Common electrode 115 is called the common electrode because it is an electrode disposed continuously in each light-emitting device.

[0074] In two adjacently arranged light-emitting devices, it is preferable that the EL layers are formed separately and not continuously. By forming the EL layers separately, the two light-emitting devices can have different emission wavelengths. A structure in which the EL layers are formed separately is called an SBS structure. The SBS structure can be formed using a metal mask or FMM, or can be formed without using a metal mask or FMM. A structure formed without using a metal mask or FMM is called an MML structure.

[0075] Of course, the EL layers of two adjacent light-emitting devices may be continuous without being separated, or a configuration may be adopted in which parts of two adjacent light-emitting devices overlap each other using a metal mask or FMM.

[0076] In two adjacent light-emitting devices, the insulating layer 127 corresponding to the surface on which the common electrode 115 is formed preferably has a convex curved surface, which can suppress discontinuity of the common electrode 115. The insulating layer 127 having a convex curved surface preferably contains an organic material. Specific examples of organic materials will be described later. The insulating layer 127 is preferably disposed so as to overlap the edge of the EL layer. Furthermore, in order to suppress deterioration of the light-emitting device, it is preferable that the edge of the EL layer is covered with the insulating layer 127. In this case, it is preferable that the insulating layer 127 contains an inorganic material, as this enhances the effect of suppressing moisture penetration into the light-emitting device. Specific examples of inorganic materials will be described later. In order to achieve the effect of suppressing discontinuity of the common electrode and the effect of suppressing deterioration of the light-emitting device, it is preferable that the insulating layer corresponding to the insulating layer 127 is a laminate of an organic material and an inorganic material.

[0077] The layer 101 having the transistor (hereinafter referred to as layer 101) includes a substrate 103. The substrate 103 can be a glass substrate, a quartz substrate, a ceramic substrate, a sapphire substrate, a resin substrate, a metal substrate, an alloy substrate, a semiconductor substrate, or the like. The top surface of the substrate 103 has high flatness, and is therefore suitable as a reference surface for determining the height. A material that transmits light, i.e., visible light, is used for the substrate on the side from which light from the light-emitting device is extracted.

[0078] Using a flexible material for the substrate 103 can increase the flexibility of the display device and realize a flexible display. A resin substrate is also preferred as a flexible material. Examples of resin substrates that can be used include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resins, acrylic resins, polyimide resins, polymethyl methacrylate resins, polycarbonate (PC) resins, polyethersulfone (PES) resins, polyamide resins (nylon, aramid, etc.), polysiloxane resins, cycloolefin resins, polystyrene resins, polyamideimide resins, polyurethane resins, polyvinyl chloride resins, polyvinylidene chloride resins, polypropylene resins, polytetrafluoroethylene (PTFE) resins, ABS resins, and cellulose nanofibers. Using a polarizing plate as the substrate 103 is also preferred because it increases flexibility. Furthermore, glass having a thickness sufficient to provide flexibility can also be used for the substrate 103.

[0079] Furthermore, the layer 101 includes a transistor 253R, a plug 256R, a transistor 253G, a plug 256G, a transistor 253B, a plug 256B, an insulating layer 104, and the like on the substrate 103. The configuration of the transistor is not limited in any way, and an example is shown in which a transistor is arranged in the region surrounded by a dashed line in the figure. In this specification, a plug is used as a conductive layer and refers to a shape whose vertical width is greater than its horizontal width in a cross-sectional view. The use of such a plug is preferable because it allows for increased integration. Of course, a conductive layer (whose vertical width is smaller than its horizontal width) may be used instead of a plug. Although not shown, the layer 101 includes at least one of a capacitor element and a wiring in addition to a transistor.

[0080] The plug 256R is disposed to electrically connect the transistor 253R and the light-emitting device 130R, and specifically functions as a conductive layer electrically connected to one of the source and drain of the transistor 253R. The plug 256R can also function as one of the source and drain of the transistor 253R. The plug 256G is disposed to electrically connect the transistor 253G and the light-emitting device 130G, and specifically functions as a conductive layer electrically connected to one of the source and drain of the transistor 253G. The plug 256G can also function as one of the source and drain of the transistor 253G. The plug 256B is disposed to electrically connect the transistor 253B and the light-emitting device 130B, and specifically functions as a conductive layer electrically connected to one of the source and drain of the transistor 253B. The plug 256B can also function as one of the source and drain of the transistor 253B.

[0081] The plugs 256R, 256G, and 256B can be formed, for example, in the same process. The plugs 256R, 256G, and 256B may be collectively referred to as plugs 256. Each transistor can also be electrically connected to the pixel electrode 111 without using the plug 256.

[0082] Materials that can be used for the plugs 256 include, for example, one or more selected from chromium, copper, aluminum, gold, silver, zinc, tantalum, titanium, tungsten, manganese, nickel, iron, cobalt, molybdenum, and niobium. Other materials that can be used for the plugs 256 include alloys containing one or more of the above-mentioned metals. A conductive material with low electrical resistivity can be suitably used for the plugs 256, and examples of conductive materials with low electrical resistivity include one or more selected from copper, silver, gold, and aluminum. Copper and aluminum are particularly preferred materials for the plugs 256 because of their excellent mass productivity.

[0083] A Cu—X alloy film (X is Mn, Ni, Cr, Fe, Co, Mo, Ta, or Ti) can also be applied to the plug 256. By using a Cu—X alloy film, it can be processed by wet etching, thereby reducing manufacturing costs.

[0084] An oxide conductor can be used for the plug 256. Examples of oxide conductors include indium oxide, zinc oxide, In—Sn oxide (ITO), In—Zn oxide (also referred to as IZO (registered trademark)), In—W oxide, In—W—Zn oxide, In—Ti oxide, In—Ti—Sn oxide, In—Sn—Si oxide (also referred to as ITO containing silicon, ITSO), zinc oxide doped with gallium, In—Ga—Zn oxide (also referred to as IGZO), and In—Sn—Zn oxide (also referred to as ITZO (registered trademark)). In particular, oxide conductors containing indium are preferred as materials for the plug 256 due to their high conductivity.

[0085] The plug 256 can have a stacked structure of a conductive film containing an oxide conductor and a conductive film containing a metal or an alloy. By using a conductive film containing a metal or an alloy, the wiring resistance of the plug 256 can be reduced.

[0086] The insulating layer 104 covers each transistor and serves as a surface on which each pixel electrode is formed. The surface on which each pixel electrode is formed, that is, the top surface of the insulating layer 104, is preferably highly flat, and the insulating layer 104 preferably contains an organic material. Furthermore, the insulating layer 104 preferably contains an inorganic material, which can prevent moisture or impurities from entering the EL layer. The insulating layer corresponding to the insulating layer 104 is preferably a laminate of an organic material and an inorganic material.

[0087] The insulating layer 104 can be an inorganic insulating layer containing an inorganic material (referred to as an inorganic insulating layer) or an insulating layer containing an organic material (referred to as an organic insulating layer). In this specification, examples of organic materials include acrylic resin and polyimide resin. In this specification, examples of inorganic materials include oxides, nitrides, oxynitrides, and nitride oxides. Examples of oxides include silicon oxide, aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, tantalum oxide, cerium oxide, gallium zinc oxide, and hafnium aluminate. Examples of nitrides include silicon nitride and aluminum nitride. Examples of oxynitrides include silicon oxynitride, aluminum oxynitride, gallium oxynitride, yttrium oxynitride, and hafnium oxynitride. Examples of nitride oxides include silicon nitride oxide and aluminum nitride oxide.

[0088] In this specification and the like, an oxynitride refers to a material having a composition in which oxygen is contained in a larger amount than nitrogen, and a nitride oxide refers to a material having a composition in which nitrogen is contained in a larger amount than oxygen.

[0089] In the cross-sectional view shown in FIG. 2A , the light-shielding layer 109 has a region located between the pixel electrodes 111R and 111G. The light-shielding layer 109 also has a region located between the pixel electrodes 111G and 111B. The light-shielding layer 109 is a continuous layer when viewed from above. By providing the light-shielding layer 109, light emitted from each light-emitting device is prevented from entering each transistor. The light includes visible light, and the wavelength of visible light is 380 nm or more and 780 nm or less. The light also includes ultraviolet light, and the wavelength of ultraviolet light is less than 380 nm. The light also includes infrared light, and the wavelength of infrared light is longer than 780 nm. Sources of light include not only light-emitting devices but also light from outside the display device 100 (also referred to as ambient light). In this specification, ambient light is included in light.

[0090] When using transistors whose electrical characteristics are degraded by light of the above wavelengths, the light-shielding layer 109 can preferably prevent light from entering at least the semiconductor layer of each transistor, particularly the channel formation region. The wavelength of light that is likely to degrade a transistor can be estimated based on the band gap of the semiconductor material used in the channel formation region, but it is preferable that light of any wavelength is not incident on the transistor. This can prevent fluctuations in the electrical characteristics of the transistor due to light, and provide a highly reliable display device.

[0091] The light-shielding layer 109 preferably has low transmittance for light of the above-mentioned wavelengths. Note that low light transmittance may be referred to as high light-shielding property. To obtain a light-shielding layer with high light-shielding property, it is preferable to use a material that does not easily transmit light of the above-mentioned wavelengths for the light-shielding layer 109. As the material that does not easily transmit light, one or more materials selected from a material that has high absorbance for light of the above-mentioned wavelengths, a material that has high reflectance for the light, and a material that has high absorbance and reflectance for the light can be used for the light-shielding layer 109.

[0092] The light-shielding layer 109 is preferably made of an insulating material, which is preferable because it can reduce leakage current between pixel electrodes. The light-shielding layer 109 is preferably made of an organic material, such as a colored organic material. Examples of colored organic materials include one or more selected from organic materials containing pigments, organic materials containing dyes, organic materials with light absorption properties (e.g., resins such as polyimides), and organic materials usable for color filters (hereinafter also referred to as color filter materials). Examples of pigments include carbon black. Red (wavelength: 640 nm to 780 nm), brown, or black is preferably used as the color of the light-shielding layer 109. Furthermore, it is preferable to use a resin in which two or more color filter materials are laminated or mixed, as this can enhance light-shielding properties. In the case of a two-color color filter material, it is preferable to laminate a red color filter and a green color filter. Furthermore, a resin in black or near-black can be obtained by mixing three or more color filter materials.

[0093] The light-shielding layer 109 preferably has low transmittance to light with higher energy than the band gap of the semiconductor material used in the channel formation region of the transistor 253, that is, light with a short wavelength. This can more effectively suppress fluctuations in the electrical characteristics of the transistor 253, thereby providing a display device with higher reliability.

[0094] The semiconductor material used for the channel formation region of the transistor 253 is not particularly limited. For example, a semiconductor made of an element or a compound semiconductor can be used. Examples of semiconductors made of an element include silicon and germanium. Examples of compound semiconductors include gallium arsenide and silicon germanium. Other examples of compound semiconductors include organic semiconductors, nitride semiconductors, and oxide semiconductors (OS: oxide semiconductor). Note that these semiconductor materials may contain impurities as dopants.

[0095] Silicon used as a semiconductor material includes single crystal silicon, polycrystalline silicon, microcrystalline silicon, and amorphous silicon. Examples of polycrystalline silicon include low temperature polysilicon (LTPS). A transistor using amorphous silicon in a channel formation region can be formed on a large glass substrate and manufactured at low cost. A transistor using polycrystalline silicon in a channel formation region has high field-effect mobility and can operate at high speed. Furthermore, a transistor using microcrystalline silicon in a channel formation region has higher field-effect mobility than a transistor using amorphous silicon and can operate at high speed.

[0096] When an oxide semiconductor is used as the semiconductor material, the semiconductor layer can be referred to as a metal oxide layer. The band gap of the metal oxide used for the semiconductor layer is preferably 2.0 eV or more, and more preferably 2.5 eV or more. Therefore, the light-shielding layer 109 preferably has low transmittance for light with a short wavelength. For example, it is more preferable that the transmittance be low for light emitted from the blue light-emitting device 130B. In particular, the transmittance of the light-shielding layer 109 for light with a wavelength in the range of 300 nm to 550 nm is preferably 50% or less, more preferably 40% or less, even more preferably 20% or less, even more preferably 10% or less, and even more preferably 5% or less. When a colored organic material is used for the light-shielding layer 109 that can achieve the above transmittance, the color of the organic material is preferably red, brown, or black. By setting the color within the above range, light is prevented from entering the transistor 253, thereby resulting in a highly reliable transistor and a highly reliable display device. Note that the transmittance of the light-shielding layer 109 is not limited to the above range.

[0097] A transistor using an oxide semiconductor (hereinafter referred to as an OS transistor) has extremely high field-effect mobility compared to a transistor using amorphous silicon. Furthermore, an OS transistor has an extremely low off-state current and can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display device.

[0098] The transistor 253 can overlap with the pixel electrode 111, and a conductive material used for the pixel electrode 111 can block light. Furthermore, the light-shielding layer 109 can block light from between pixel electrodes, and therefore, according to one embodiment of the present invention, light directly above the transistor 253 as well as light from the side and oblique directions can be blocked. In view of these circumstances, the transistor 253 does not need to overlap with the light-shielding layer 109, which is preferable because it increases the degree of freedom in the layout of the light-shielding layer 109. More specifically, the light-shielding layer 109 does not need to overlap with the semiconductor layer of the transistor 253, particularly the channel formation region. This is also preferable because it increases the degree of freedom in the layout of the transistor 253. Furthermore, since multiple transistors are arranged in the layer 101, transistors electrically connected to the pixel electrode, such as the transistor 253, do not need to overlap with the light-shielding layer 109, but other transistors may overlap with the light-shielding layer 109.

[0099] Next, FIG. 1B shows a top view of a part of the display device 100, which clearly shows the pixel electrode 111 and the light-shielding layer 109. In the top view shown in FIG. 1B, the transistor 253R, the transistor 253G, and the transistor 253B shown in FIG. 2A and the like are also indicated by dashed lines. In the display device 100, the light-shielding layer 109 can be preferably provided in a region that does not overlap with any of the transistors 253R, 253G, and 253B. Note that the light-shielding layer 109 may also have a region that overlaps with parts of the transistors 253R, 253G, and 253B.

[0100] In the display device 100, the transistor 253 does not need to be arranged so as to overlap with the light-shielding layer 109. In other words, a semiconductor layer included in the transistor 253, particularly a channel formation region, does not need to be arranged so as to overlap with the light-shielding layer 109. The light-shielding layer 109 may be arranged in any manner as long as it can prevent light from above the transistor 253 from being incident on the transistor 253. The display device 100 is preferable because it has a high degree of freedom in the layout of the light-shielding layer 109 and the transistor 253.

[0101] When light emitted from a light-emitting device is incident on a transistor, the electrical characteristics of the transistor may fluctuate. It is preferable that the amount of light incident on the semiconductor layer of the transistor, particularly on the channel formation region, is small. By providing the light-shielding layer 109 between the pixel electrodes, it is possible to prevent light from entering the layer 101. This makes it possible to prevent the electrical characteristics of the transistor from fluctuating due to light. Therefore, a highly reliable transistor can be obtained, and a highly reliable display device can be provided.

[0102] Furthermore, the light-shielding layer 109 prevents light from entering the layer 101, thereby preventing stray light from being reflected or scattered by wiring or the like included in the layer 101. This allows a display device with high contrast and high visibility to be obtained.

[0103] One of the indicators for evaluating the reliability of a transistor is a Gate Bias Temperature (GBT) stress test, in which the transistor is held in a state in which an electric field is applied to the gate. Among these, a test in which a positive potential (positive bias) is applied to the gate relative to the source potential and drain potential and the transistor is held at a high temperature is called a Positive Bias Temperature Stress (PBTS) test, and a test in which a negative potential (negative bias) is applied to the gate and the transistor is held at a high temperature is called a Negative Bias Temperature Stress (NBTS) test. The PBTS test and the NBTS test performed under light irradiation are called a PBTIS (Positive Bias Temperature Illumination Stress) test and a NBTIS (Negative Bias Temperature Illumination Stress) test, respectively. It is preferable that a transistor has small fluctuations in electrical characteristics under light irradiation and high reliability against light. The reliability against light can be evaluated, for example, by the amount of fluctuation in threshold voltage in the NBTIS test.

[0104] (Alternative Form 1 of Light-Shielding Layer 109) FIG. 2B shows a structure of the light-shielding layer 109 different from that shown in FIG. 2A, in which the light-shielding layer 109 is embedded in the insulating layer 104. In this structure, the lower surface of the light-shielding layer 109 is located below the lower surface of the pixel electrode 111. Note that other configurations in FIG. 2B are similar to those in FIG. 2A and therefore will not be described further. In order to embed the light-shielding layer 109 in the layer 101, it is preferable that the insulating layer 104 has an opening or a recess. With this configuration, part or all of the light-shielding layer 109 is embedded in the opening or the recess. In this configuration, it is preferable that the side of the opening or the recess and the side of the light-shielding layer 109 have a region in contact with each other. However, an insulating layer may be interposed between the side of the opening or the recess and the side of the light-shielding layer 109. It is also preferable that the bottom of the opening or the recess and the bottom of the light-shielding layer 109 have a region in contact with each other. However, an insulating layer may be interposed between the bottom surface of the opening or recess and the bottom surface of the light-shielding layer 109. The side surface of the opening or recess may have a tapered shape. The bottom of the opening or recess may have a concave curved surface. The peripheral edge of the bottom of the opening or recess may be rounded. The upper surface of the light-shielding layer 109 may have a concave curved surface in accordance with the concave curved surface of the bottom of the opening or recess.

[0105] The thicker the light-shielding layer 109, the greater the light-shielding effect. For example, the light-shielding layer 109 of the display device 100 shown in FIG. 2B can be made thicker than the light-shielding layer 109 of the display device 100 shown in FIG. 2A, and therefore can be said to have a configuration with a high light-shielding effect. It is preferable to form the opening or recess in FIG. 2B in an insulating layer that is thicker than other insulating layers, such as the insulating layer 104. The opening or recess provided in the insulating layer 104 can have a depth that ensures sufficient light-shielding properties of the light-shielding layer 109.

[0106] The opening or recess can be positioned using the pixel electrode 111. Since the pixel electrode and the light-shielding layer 109 are continuously present between the EL layer and the transistor in a cross-sectional view, it is possible to effectively prevent light from entering the transistor.

[0107] (Alternative Form 2 of Light-Shielding Layer 109) FIG. 2C shows a structure of the light-shielding layer 109 different from those shown in FIGS. 2A and 2B. The light-shielding layer 109 is embedded in the insulating layer 104, and the upper surface of the light-shielding layer 109 is lower than the upper surface of the insulating layer 104. Of course, the upper surface of the light-shielding layer 109 may be flush with the upper surface of the insulating layer 104. In this case, the light-shielding layer 109 may overlap with a portion of the pixel electrode 111R and a portion of the pixel electrode 111G, and may not have a region located between the pixel electrode 111R and the pixel electrode 111G in a cross-sectional view. The light-shielding layer 109 may also overlap with a portion of the pixel electrode 111G and a portion of the pixel electrode 111B, and may not have a region located between the pixel electrode 111G and the pixel electrode 111B in a cross-sectional view. The light-shielding layer 109 is a continuous layer when viewed from above. When such a light-shielding layer is used, the pixel electrode and the light-shielding layer 109 are generally continuous between the EL layer and the transistor in a cross-sectional view, so that light can be effectively prevented from entering the transistor.

[0108] The other configurations are the same as those in FIG. 2B, and the description thereof will be omitted.

[0109] 3A , in the display device 100 according to one embodiment of the present invention, the EL layer 113R1 is preferably provided so as to have a width narrower than that of the pixel electrode 111R in a cross-sectional view. In other words, the EL layer 113R1 is preferably formed on the upper surface of the pixel electrode 111R and does not have a region extending from the pixel electrode 111R.

[0110] The EL layer 113G1 of the light-emitting device 130G is preferably provided so as to be narrower than the pixel electrode 111G in cross-sectional view. In other words, the EL layer 113G1 is preferably formed on the upper surface of the pixel electrode 111G and does not have a region extending from the pixel electrode 111G.

[0111] The EL layer 113B1 of the light-emitting device 130B is preferably provided so as to be narrower than the pixel electrode 111B in cross-sectional view. In other words, the EL layer 113B1 is preferably formed on the upper surface of the pixel electrode 111B and does not have a region extending from the pixel electrode 111B.

[0112] In the light-emitting device 130, the EL layer 113 may not emit light in the region extending from the pixel electrode 111. Furthermore, when the EL layer 113 extends from the pixel electrode 111, it may be affected by electric field concentration at the upper end of the pixel electrode 111. When the EL layer 113 is affected by electric field concentration, bright spots may occur. Furthermore, deterioration of the EL layer 113 is likely to progress from the area of ​​electric field concentration. Furthermore, when the light-emitting device 130 employs a tandem structure (described below), a structure in which a first EL layer, a charge generation layer, and a second EL layer are stacked in order is adopted. However, the charge generation layer in the region extending over the upper end of the pixel electrode 111 is likely to approach the upper end of the pixel electrode 111, which may result in current flow between the charge generation layer and the pixel electrode 111. A current flowing through a location where current should not flow is called a leakage path. The display device shown in FIG. 3A can suppress the above-mentioned electric field concentration and leakage path, and is a particularly preferable configuration example when the light-emitting device 130 employs a tandem structure.

[0113] The other configurations of Fig. 3A are the same as those of Fig. 2B, and therefore will not be described further. The light-shielding layer 109 shown in Fig. 2A and Fig. 2C can also be applied to the light-emitting device shown in Fig. 3A.

[0114] 3B , the display device 100 according to one embodiment of the present invention preferably includes an insulating layer 139 that covers the light-shielding layer 109. The insulating layer 139 can prevent gas, impurities, or moisture from the light-shielding layer 109 from entering the EL layer 113 or the like.

[0115] The insulating layer 139 preferably includes an inorganic material. Examples of inorganic materials include oxides, nitrides, oxynitrides, and nitride oxides. Examples of oxides include silicon oxide, aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, tantalum oxide, cerium oxide, gallium zinc oxide, and hafnium aluminate. Examples of nitrides include silicon nitride and aluminum nitride. Examples of oxynitrides include silicon oxynitride, aluminum oxynitride, gallium oxynitride, yttrium oxynitride, and hafnium oxynitride. Examples of nitride oxides include silicon nitride oxide and aluminum nitride oxide.

[0116] In this specification and the like, an oxynitride refers to a material having a composition in which oxygen is contained in a larger amount than nitrogen, and a nitride oxide refers to a material having a composition in which nitrogen is contained in a larger amount than oxygen.

[0117] The insulating layer 139 can suppress discontinuity that occurs when the EL layer 113 extends from the pixel electrode 111. In particular, when a tandem structure, which will be described later, is used in the light-emitting device 130, the insulating layer 139 can reduce the difference between the upper surface position of the pixel electrode 111 and the upper surface position of the light-shielding layer 109, thereby suppressing discontinuity of the EL layer 113.

[0118] Furthermore, it is preferable that the insulating layer 139 has an area that overlaps with a portion of the pixel electrode 111. Even if electric field concentration occurs at the upper end of the pixel electrode 111, the insulating layer 139 can separate the EL layer 113 from the upper end of the pixel electrode 111, thereby suppressing the effects of the electric field concentration. In particular, when a tandem structure, which will be described later, is used in the light-emitting device 130, the insulating layer 139 can sufficiently separate the EL layer 113 from the upper end of the pixel electrode 111, thereby suppressing the occurrence of a leak path between the charge generating layer and the upper end of the pixel electrode 111. In other words, the display device shown in FIG. 3B does not cause the above-mentioned leak path to occur, and is therefore a preferable configuration example when using a tandem structure.

[0119] The other configurations in Fig. 3B are the same as those in Fig. 2B, and therefore will not be described further. The light-shielding layer 109 shown in Fig. 2A and Fig. 2C can also be applied to the light-emitting device shown in Fig. 3B.

[0120] 3C , the display device 100 according to one embodiment of the present invention may include an insulating layer 139a covering the light-shielding layer 109 and an insulating layer 139b provided over the insulating layer 139a. The insulating layer 139a can prevent gas, impurities, or moisture from the light-shielding layer 109 from entering the EL layer 113 or the like. The insulating layer 139b can prevent gas, impurities, or moisture from the light-shielding layer 109 from entering the EL layer 113 or the like.

[0121] The insulating layer 139a preferably includes an inorganic material. The insulating layer 139b preferably includes an inorganic material. Examples of inorganic materials include oxides, nitrides, oxynitrides, and nitride oxides. Examples of oxides include silicon oxide, aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, tantalum oxide, cerium oxide, gallium zinc oxide, and hafnium aluminate. Examples of nitrides include silicon nitride and aluminum nitride. Examples of oxynitrides include silicon oxynitride, aluminum oxynitride, gallium oxynitride, yttrium oxynitride, and hafnium oxynitride. Examples of nitride oxides include silicon nitride oxide and aluminum nitride oxide.

[0122] The insulating layers 139a and 139b are preferably provided so as to have an area overlapping a portion of the pixel electrode 111. Even if electric field concentration occurs at the upper end of the pixel electrode 111, the insulating layers 139a and 139b can separate the EL layer 113 from the upper end of the pixel electrode 111, thereby suppressing the effects of the electric field concentration. In particular, when a tandem structure (described later) is used in the light-emitting device 130, the insulating layers 139a and 139b can sufficiently separate the EL layer 113 from the upper end of the pixel electrode 111, thereby suppressing the occurrence of a leak path between the charge generating layer and the upper end of the pixel electrode 111. In other words, the display device shown in FIG. 3C does not cause the above-mentioned leak path to occur, and is therefore a preferable configuration example when using a tandem structure.

[0123] The insulating layers 139a and 139b can suppress a step that occurs when the EL layer 113 exceeds the pixel electrode 111. In particular, when a tandem structure described later is used in the light-emitting device 130, the insulating layers 139a and 139b can reduce the difference between the upper surface position of the pixel electrode 111 and the upper surface position of the light-shielding layer 109, thereby suppressing step discontinuity of the EL layer 113.

[0124] The other configurations in Fig. 3C are the same as those in Fig. 2B, and therefore will not be described further. The light-shielding layer 109 shown in Fig. 2A and Fig. 2C can also be applied to the light-emitting device shown in Fig. 3C.

[0125] 3D , the display device 100 according to one embodiment of the present invention can include a conductive layer 137 over the pixel electrode 111 and the light-shielding layer 109. The conductive layer 137 preferably has an end face coinciding with an end face of the EL layer 113. The conductive layer 137 can prevent the top surface and the upper layer of the light-shielding layer 109 from being removed when the EL layer 113 is processed.

[0126] The conductive layer 137 preferably includes an oxide conductor. As the oxide conductor, for example, one or more selected from In—Sn oxide (ITO), In—Si—Sn oxide (ITSO), In—Zn oxide (IZO (registered trademark)), In—Ga—Zn oxide (IGZO), and In—Sn—Zn oxide (ITZO (registered trademark)) can be preferably used.

[0127] The conductive layer 137 prevents the upper surface and upper layer of the light-shielding layer 109 from being removed, so that a high light-shielding effect can be maintained.

[0128] The other configurations in Fig. 3D are the same as those in Fig. 2B, and therefore will not be described further. The light-shielding layer 109 shown in Fig. 2A and Fig. 2C can also be applied to the light-emitting device shown in Fig. 3D.

[0129] [Specific Example 1] A specific example of a display device 100 according to one embodiment of the present invention will be described. FIG. 1A shows a top view of the display device 100. FIGS. 4A and 4B show cross-sectional views taken along dashed dotted lines X1-X2 in FIG. 1A. The display device 100 shown in FIG. 4A is based on the representative example shown in FIG. 2A, and the display device 100 shown in FIG. 4B is based on the representative example shown in FIG. 2B. Specifically, the display device 100 shown in FIG. 4B is characterized in that the thickness of the light-shielding layer 109 is thicker than the thickness of the light-shielding layer 109 of the display device 100 shown in FIG. 4A. Therefore, the display device 100 shown in FIG. 4B has a configuration with a high light-shielding effect. The display device configurations shown in FIGS. 2C to 3D can also be applied to specific example 1.

[0130] 4A and 4B, a protective layer 131 is preferably provided to cover the light-emitting devices 130R, 130G, and 130B. The protective layer 131 can prevent impurities or moisture from entering the light-emitting devices.

[0131] 4A and 4B , the substrate 120 is preferably attached to the protective layer 131 with a resin layer 122. Note that in the display device 100 according to one embodiment of the present invention, the substrate 120 can be attached to the protective layer 131 using a sealant or the like without providing the resin layer 122. A display device having a structure in which the resin layer 122 is not provided is called a hollow structure.

[0132] In the display device 100 shown in FIGS. 4A and 4B , the layer 101 includes a substrate 103 and a transistor on the substrate 103. Although transistors are not shown in FIGS. 4A and 4B , the display device 100 can, of course, include transistors similar to those in the display device 100 shown in FIG. 1A . An insulating layer capable of planarizing unevenness due to the transistors is provided over the transistors. Conductive layers 250R, 250G, and 250B, as well as plugs 256R, 256G, and 256B, are preferably formed on the insulating layer, and an insulating layer 104 capable of planarizing unevenness due to the plugs 256R, 256G, and 256B is preferably formed on the insulating layer. The insulating layer 104 can have a single-layer structure or a stacked-layer structure. The conductive layer 250R is electrically connected to the plug 256R, the conductive layer 250G is electrically connected to the plug 256G, and the conductive layer 250B is electrically connected to the plug 256B. The conductive layers 250R, 250G, and 250B may be collectively referred to as conductive layers 250. The plugs 256R, 256G, and 256B may be collectively referred to as plugs 256. The conductive layers 250 are electrically connected to transistors on the substrate 103.

[0133] The light-emitting device 130R includes a pixel electrode 111R, an island-shaped EL layer 113R on the pixel electrode 111R, a common layer 114 on the EL layer 113R, and a common electrode 115 on the common layer 114. In the light-emitting device 130R, the EL layer 113R includes at least a light-emitting layer, and the light-emitting layer and other layers can be collectively referred to as the EL layer. The pixel electrode 111R is electrically connected to a plug 256R.

[0134] The light-emitting device 130G includes a pixel electrode 111G, an island-shaped EL layer 113G on the pixel electrode 111G, a common layer 114 on the EL layer 113G, and a common electrode 115 on the common layer 114. In the light-emitting device 130G, the EL layer 113G includes at least a light-emitting layer, and the light-emitting layer and other layers can be collectively referred to as the EL layer. The pixel electrode 111G is electrically connected to a plug 256G.

[0135] The light-emitting device 130B includes a pixel electrode 111B, an island-shaped EL layer 113B on the pixel electrode 111B, a common layer 114 on the EL layer 113B, and a common electrode 115 on the common layer 114. In the light-emitting device 130B, the EL layer 113B includes at least a light-emitting layer, and the light-emitting layer and other layers can be collectively referred to as the EL layer. The pixel electrode 111B is electrically connected to a plug 256B.

[0136] The pixel electrodes 111R, 111G, and 111B may be formed in the same process, for example. The pixel electrodes 111R, 111G, and 111B may be collectively referred to as pixel electrodes 111.

[0137] In this specification, among the EL layers of the light-emitting devices, the layer provided in an island shape for each light-emitting device is referred to as EL layer 113B, EL layer 113G, or EL layer 113R, and the layer shared by multiple light-emitting devices is referred to as common layer 114.

[0138] The EL layer 113R, the EL layer 113G, and the EL layer 113B are spaced apart from one another. By providing an island-like EL layer for each light-emitting device, leakage current between adjacent light-emitting devices can be suppressed. This prevents unintended light emission due to crosstalk, and realizes a display device with extremely high contrast. In particular, a display device with high current efficiency at low brightness can be realized.

[0139] The pixel electrode 111 and the common electrode 115, which function as a pair of electrodes of the light-emitting device, can each be made of a metal, an alloy, an electrically conductive compound, or a mixture thereof. Specifically, the pixel electrode 111 and the common electrode 115 preferably contain a metal such as aluminum, magnesium, titanium, chromium, manganese, iron, cobalt, nickel, copper, gallium, zinc, indium, tin, molybdenum, tantalum, tungsten, palladium, gold, platinum, silver, yttrium, or neodymium, or an alloy of an appropriate combination of these metals. The pixel electrode 111 and the common electrode 115 preferably contain indium tin oxide (In—Sn oxide, also referred to as ITO), In—Si—Sn oxide (ITSO), indium zinc oxide (In—Zn oxide), or In—W—Zn oxide. The pixel electrode 111 and the common electrode 115 preferably contain an alloy containing aluminum (aluminum alloy) or an alloy containing silver. Examples of the aluminum alloy include an alloy of aluminum, nickel, and lanthanum (Al-Ni-La), and examples of the alloy containing silver include an alloy of silver and magnesium, and an alloy of silver, palladium, and copper (Ag-Pd-Cu, also referred to as APC).The pixel electrode 111 and the common electrode 115 preferably each include an element belonging to Group 1 or 2 of the periodic table (e.g., lithium, cesium, calcium, strontium) not exemplified above, a rare earth metal such as europium or ytterbium, an alloy containing an appropriate combination of these, or graphene.

[0140] Of the pair of electrodes that a light-emitting device has, one electrode functions as an anode and the other electrode functions as a cathode. In the following, an example in which the pixel electrode functions as the anode and the common electrode functions as the cathode will be described.

[0141] FIG. 5 shows an enlarged view of a portion of the display device 100 shown in FIG. 4A . In the display device 100, an insulating layer 125 and an insulating layer 127 on the insulating layer 125 are provided in the region between adjacent light-emitting devices. Although multiple insulating layers 125 and multiple insulating layers 127 are shown in the cross-sectional views of FIG. 4A and FIG. 5 , when the display device 100 is viewed from above, the insulating layers 125 and the insulating layers 127 are each connected to one another. Note that the display device 100 may be configured to have multiple insulating layers 125 that are separated from one another and multiple insulating layers 127 that are separated from one another.

[0142] The display device 100 according to one embodiment of the present invention can be a top emission type (top emission type) in which light is extracted from the opposite direction to the substrate on which the light emitting device is formed, a bottom emission type (bottom emission type) in which light is extracted from the substrate side on which the light emitting device is formed, or a dual emission type (dual emission type) in which light is emitted from both sides.

[0143] As the light-emitting device, for example, an OLED (organic light-emitting diode) or a QLED (quantum-dot light-emitting diode) is preferably used. Examples of the light-emitting material contained in the light-emitting device include a fluorescent material (fluorescent material), a phosphorescent material (phosphorescent material), a material exhibiting thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) material), and an inorganic compound (quantum dot material, etc.). Furthermore, an LED such as a micro LED (light-emitting diode) can also be used as the light-emitting device.

[0144] The light-emitting devices may emit light of infrared, red, green, blue, cyan, magenta, yellow, or white. In the display device 100, the light-emitting device 130R emits red (R) light, the light-emitting device 130G emits green (G) light, and the light-emitting device 130B emits blue (B) light, and these lights can be extracted to the outside. In addition, in the display device 100, by providing the light-emitting devices with a microcavity structure, the color purity of each emitted color can be improved.

[0145] 4A and 5, an insulating layer (also called a partition wall, bank, or spacer) covering the upper end of the pixel electrode 111 is not provided. Therefore, the distance between adjacent light-emitting devices can be made extremely narrow. Therefore, a high-definition or high-resolution display device can be obtained.

[0146] By not providing an insulating layer covering the upper surface end of the pixel electrode 111, light emitted from the EL layer can be efficiently extracted. Therefore, the display device 100 according to one embodiment of the present invention can have extremely small viewing angle dependency. By reducing the viewing angle dependency, the visibility of images in the display device 100 can be improved. For example, in the display device 100 according to one embodiment of the present invention, the viewing angle (the maximum angle at which a certain contrast ratio is maintained when the screen is viewed from an oblique direction) can be set to a range of 100° or more and less than 180°, preferably 150° or more and 170° or less. Note that the above viewing angle can be applied to both the vertical and horizontal directions.

[0147] The light emitting device of this embodiment can have a single structure (a structure having only one light emitting unit) or a tandem structure (a structure having a plurality of light emitting units).

[0148] When a light-emitting device with a tandem structure is used, it is preferable that the EL layer 113R has a structure having a plurality of light-emitting units that emit red light, the EL layer 113G has a structure having a plurality of light-emitting units that emit green light, and the EL layer 113B has a structure having a plurality of light-emitting units that emit blue light. It is preferable to provide a charge generation layer between each of the light-emitting units. The light-emitting unit has at least one light-emitting layer, and includes a light-emitting unit having one or more light-emitting layers between the charge generation layer and the anode, and a light-emitting unit having one or more light-emitting layers between the charge generation layer and the cathode.

[0149] The EL layer 113R, the EL layer 113G, and the EL layer 113B may each have one or more of a light-emitting layer, a hole injection layer, a hole transport layer, a hole blocking layer, a charge generation layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0150] For example, the EL layer 113R, the EL layer 113G, and the EL layer 113B may each have a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer in this order. Alternatively, an electron blocking layer may be provided between the hole transport layer and the light-emitting layer. Alternatively, a hole blocking layer may be provided between the electron transport layer and the light-emitting layer. Alternatively, an electron injection layer may be provided on the electron transport layer.

[0151] For example, the EL layer 113R, the EL layer 113G, and the EL layer 113B may each have an electron injection layer, an electron transport layer, an emitting layer, and a hole transport layer in this order. Alternatively, a hole blocking layer may be provided between the electron transport layer and the emitting layer. Alternatively, an electron blocking layer may be provided between the hole transport layer and the emitting layer. Alternatively, a hole injection layer may be provided on the hole transport layer.

[0152] As described above, the EL layers 113R, 113G, and 113B each preferably have a light-emitting layer and a carrier transport layer (electron transport layer or hole transport layer) on the light-emitting layer. Alternatively, the EL layers 113R, 113G, and 113B each preferably have a light-emitting layer and a carrier block layer (hole block layer or electron block layer) on the light-emitting layer. Alternatively, the EL layers 113R, 113G, and 113B each preferably have a light-emitting layer, a carrier block layer on the light-emitting layer, and a carrier transport layer on the carrier block layer. Since the surfaces of the EL layers 113R, 113G, and 113B are exposed during the manufacturing process of the display device, providing one or both of the carrier transport layer and the carrier block layer on the light-emitting layer can prevent the light-emitting layer from being exposed to the outermost surface and reduce damage to the light-emitting layer. This can improve the reliability of the light-emitting device.

[0153] The compounds contained in the EL layer 113R, the EL layer 113G, and the EL layer 113B are preferably organic compounds, and the heat resistance temperature of the organic compounds is preferably 100° C. or higher and 180° C. or lower, preferably 120° C. or higher and 180° C. or lower, and more preferably 140° C. or higher and 180° C. or lower. For example, the glass transition point (Tg) of these compounds is preferably 100° C. or higher and 180° C. or lower, preferably 120° C. or higher and 180° C. or lower, and more preferably 140° C. or higher and 180° C. or lower.

[0154] In particular, it is preferable that the organic compound provided on the light-emitting layer has a high heat resistance temperature. Furthermore, it is even more preferable that the organic compound provided on and in contact with the light-emitting layer has a high heat resistance temperature. The high heat resistance of the organic compound makes it possible to effectively protect the light-emitting layer and reduce damage to the light-emitting layer.

[0155] It is preferable that the light-emitting layer has a high heat resistance temperature, which can prevent the light-emitting layer from being damaged by heat, resulting in a decrease in light-emitting efficiency and a shortened lifespan.

[0156] The light-emitting layer contains a light-emitting substance (also referred to as a light-emitting material, a light-emitting compound, a guest material, or the like) and an organic compound (also referred to as a host material, or the like). Since the light-emitting layer contains a larger amount of the organic compound than the light-emitting substance, the glass transition point (Tg) of the organic compound can be used as an index of the heat resistance temperature of the light-emitting layer.

[0157] The EL layer 113R, the EL layer 113G, and the EL layer 113B preferably have, for example, a first light-emitting unit, a charge generation layer on the first light-emitting unit, and a second light-emitting unit on the charge generation layer.

[0158] The first light-emitting unit and the second light-emitting unit each preferably have an emitting layer and a carrier transport layer (electron transport layer or hole transport layer) on the emitting layer. Alternatively, the first light-emitting unit and the second light-emitting unit each preferably have an emitting layer and a carrier block layer (hole block layer or electron block layer) on the emitting layer. Alternatively, the first light-emitting unit and the second light-emitting unit each preferably have an emitting layer, a carrier block layer on the emitting layer, and a carrier transport layer on the carrier block layer. The layered structure of the second light-emitting unit may be different from the layered structure of the first light-emitting unit. Note that the surface of the second light-emitting unit is exposed during the manufacturing process of the display device. Therefore, by providing one or both of the carrier transport layer and the carrier block layer on the emitting layer, exposure of the emitting layer to the outermost surface can be suppressed, thereby reducing damage to the emitting layer. This can improve the reliability of the light-emitting device. When the light-emitting device has three or more light-emitting units, the uppermost light-emitting unit preferably has a light-emitting layer and one or both of a carrier transport layer and a carrier block layer on the light-emitting layer.

[0159] The common layer 114 may include, for example, an electron injection layer or a hole injection layer. Alternatively, the common layer 114 may include a stack of an electron transport layer and an electron injection layer, or a stack of a hole transport layer and a hole injection layer. The common layer 114 is shared by the light-emitting devices 130R, 130G, and 130B.

[0160] In the display device 100, a mask layer 118R is provided at the end of the EL layer 113R, a mask layer 118G is provided at the end of the EL layer 113G, and a mask layer 118B is provided at the end of the EL layer 113B. The mask layers 118R, 118G, and 118B are collectively referred to as mask layers 118. The mask layer 118 can reduce damage to the light-emitting layer during processing of the EL layer, thereby improving the reliability of the light-emitting device. It is preferable that the mask layer 118 contains an insulating material. The mask layer can be read as an insulating layer.

[0161] To explain the film thickness of the light-shielding layer 109, cross-sectional views of the EL layer 113R, the EL layer 113G, the light-shielding layer 109, and the vicinity thereof are shown in FIG. 6 . The light transmittance of the light-shielding layer 109 can be adjusted by the material used for the light-shielding layer 109 and the thickness T109 of the light-shielding layer 109. The thickness T109 is defined as the shortest distance from the surface on which the light-shielding layer 109 is formed (here, the upper surface of the insulating layer 104) to the upper surface of the light-shielding layer 109 in the cross-sectional view. However, if the thickness T109 of the light-shielding layer 109 is thin, the light transmittance increases, and if the thickness T109 is thick, the productivity of the display device may decrease. Therefore, the thickness T109 of the light-shielding layer 109 is preferably 200 nm or more and 2000 nm or less, more preferably 200 nm or more and 1500 nm or less, even more preferably 400 nm or more and 1500 nm or less, even more preferably 400 nm or more and 1200 nm or less, and even more preferably 600 nm or more and 1200 nm or less. By setting the thickness T109 within the above-mentioned range, it is possible to reduce the light transmittance and improve the productivity of the display device. Note that the thickness T109 is not limited to the above-mentioned range. For example, the thickness T109 can be reduced by using a material with low transmittance for the light-shielding layer 109.

[0162] Next, the height H109 of the light-shielding layer 109 will be described. The reference plane for the height H109 is the upper surface of the substrate 103 in the cross-sectional view. The height H109 is also the shortest distance, similar to the thickness T109.

[0163] Next, the thickness T111 of the pixel electrode 111 will be described. The thickness T111 is the shortest distance from the surface on which the pixel electrode 111 is formed (here, the upper surface of the insulating layer 104) to the upper surface of the pixel electrode 111 in a cross-sectional view. The thickness T111 of the pixel electrode 111 is preferably 20 nm or more and 200 nm or less, more preferably 20 nm or more and 150 nm or less, even more preferably 40 nm or more and 150 nm or less, even more preferably 40 nm or more and 120 nm or less, and even more preferably 60 nm or more and 120 nm or less. Note that the thickness T111 is not limited to the above-mentioned range. When the pixel electrode 111 is stacked, the film thickness of the stacked body can be the thickness T111 of the pixel electrode 111.

[0164] Next, the height H111 of the pixel electrode 111 will be described. The reference plane for the height H111 is the upper surface of the substrate 103 in the cross-sectional view. The height H111 is also the shortest distance, similar to the thickness T111.

[0165] Fig. 7 shows an enlarged view of a portion of the display device 100 shown in Fig. 4B. Fig. 7 is an enlarged view of a configuration in which, unlike Fig. 6, the insulating layer 104 has a recess, and the recess is filled with a light-shielding layer 109. The display device shown in Fig. 7 can have a thicker thickness T109 than the display device shown in Fig. 6, and the light-shielding properties of the light-shielding layer 109 can be improved.

[0166] In FIG. 7 , the thickness T109 of the light-shielding layer 109 is the shortest distance between the surface on which the light-shielding layer 109 is formed (here, the bottom surface of the recess in the insulating layer 104) and the top surface of the light-shielding layer 109 in the cross-sectional view. The thickness T109 of the light-shielding layer 109 is preferably 200 nm or more and 2000 nm or less, more preferably 200 nm or more and 1500 nm or less, even more preferably 400 nm or more and 1500 nm or less, even more preferably 400 nm or more and 1200 nm or less, and even more preferably 600 nm or more and 1200 nm or less. By setting the thickness T109 within the above-mentioned range, the light transmittance can be reduced and the productivity of the display device can be improved. Note that the thickness T109 is not limited to the above-mentioned range. For example, the thickness T109 can be reduced by using a material with low transmittance for the light-shielding layer 109.

[0167] Next, the height H109 of the light-shielding layer 109 will be described. The reference plane for the height H109 is the upper surface of the substrate 103 in the cross-sectional view. The height H109 is also the shortest distance, similar to the thickness T109.

[0168] Next, the thickness T111 of the pixel electrode 111 will be described. The thickness T111 is the shortest distance from the surface on which the pixel electrode 111 is formed (here, the upper surface of the insulating layer 104) to the upper surface of the pixel electrode 111 in a cross-sectional view. The thickness T111 of the pixel electrode 111 is preferably 20 nm or more and 200 nm or less, more preferably 20 nm or more and 150 nm or less, even more preferably 40 nm or more and 150 nm or less, even more preferably 40 nm or more and 120 nm or less, and even more preferably 60 nm or more and 120 nm or less. Note that the thickness T111 is not limited to the above-mentioned range. When the pixel electrode 111 is stacked, the film thickness of the stacked body can be the thickness T111 of the pixel electrode 111.

[0169] Next, the height H111 of the pixel electrode 111 will be described. The reference plane for the height H111 is the upper surface of the substrate 103 in the cross-sectional view. The height H111 is also the shortest distance, similar to the thickness T111.

[0170] 7 shows an example of a configuration in which the upper surface of the light-shielding layer 109 is flat, but this embodiment of the present invention is not limited to this. As shown in Fig. 8A, the upper surface of the light-shielding layer 109 can be a concave curved surface. Alternatively, as shown in Fig. 8B, the upper surface of the light-shielding layer 109 can be a convex curved surface. This can improve the coverage of layers (e.g., EL layer 113R and EL layer 113G) provided on the light-shielding layer 109, and can prevent discontinuities in these layers.

[0171] In FIG. 8A , the thickness T109 of the light-shielding layer 109 is the shortest distance from the surface where the light-shielding layer 109 is formed (here, the bottom surface of the recess in the insulating layer 104) to the upper surface of the periphery of the light-shielding layer 109 in the cross-sectional view. The thickness T109 of the light-shielding layer 109 is preferably 200 nm or more and 2000 nm or less, more preferably 200 nm or more and 1500 nm or less, even more preferably 400 nm or more and 1500 nm or less, even more preferably 400 nm or more and 1200 nm or less, and even more preferably 600 nm or more and 1200 nm or less. By setting the thickness T109 within the above-mentioned range, the light transmittance can be reduced and the productivity of the display device can be improved. Note that the thickness T109 is not limited to the above-mentioned range. For example, the thickness T109 can be reduced by using a material with low transmittance for the light-shielding layer 109.

[0172] Next, the height H109 of the light-shielding layer 109 will be described. The reference plane for the height H109 is the upper surface of the substrate 103 in the cross-sectional view. Like the thickness T109, the height H109 is also the shortest distance from the periphery of the light-shielding layer 109 to the upper surface.

[0173] In FIG. 8B , the thickness T109 of the light-shielding layer 109 is the shortest distance from the surface on which the light-shielding layer 109 is formed (here, the bottom surface of the recess in the insulating layer 104) to the upper surface of the periphery of the light-shielding layer 109 in the cross-sectional view. The thickness T109 of the light-shielding layer 109 is preferably 200 nm or more and 2000 nm or less, more preferably 200 nm or more and 1500 nm or less, even more preferably 400 nm or more and 1500 nm or less, even more preferably 400 nm or more and 1200 nm or less, and even more preferably 600 nm or more and 1200 nm or less. By setting the thickness T109 within the above-mentioned range, the light transmittance can be reduced and the productivity of the display device can be improved. Note that the thickness T109 is not limited to the above-mentioned range. For example, the thickness T109 can be reduced by using a material with low transmittance for the light-shielding layer 109.

[0174] Next, the height H109 of the light-shielding layer 109 will be described. The reference plane for the height H109 is the upper surface of the substrate 103 in the cross-sectional view. Like the thickness T109, the height H109 is also the shortest distance from the periphery of the light-shielding layer 109 to the upper surface.

[0175] 8A and 8B, the thickness T111 and height H111 of the pixel electrode 111 are the same as those in FIG.

[0176] 6 to 8B, the height H111 and the height H111 etc. have been described using the pixel electrode 111R, but the same applies to the pixel electrode 111G and the pixel electrode 111B. This allows the area of ​​the light-emitting region of the light-emitting device to be increased, resulting in a display device with a high aperture ratio. Note that, as long as the light-shielding layer 109 does not contact the upper surface of the pixel electrode, a display device with a high aperture ratio can be obtained, so the height H109 of the light-shielding layer 109 may be greater than the height H111 of the pixel electrode 111.

[0177] An EL layer 113R is provided on the pixel electrode 111R and the light-shielding layer 109. The EL layer 113R preferably has regions in contact with the upper surface of the pixel electrode 111R and the upper surface of the light-shielding layer 109. Furthermore, it is preferable that the edge of the EL layer 113R be in contact with the upper surface of the light-shielding layer 109. By providing the EL layer 113R not only on the pixel electrode 111R but also on the light-shielding layer 109, the area of ​​the EL layer 113R can be increased. This allows the area of ​​the light-emitting region of the light-emitting device 130R to be increased, resulting in a display device with a high aperture ratio.

[0178] An EL layer 113G is provided on the pixel electrode 111G and the light-shielding layer 109. The EL layer 113G preferably has regions in contact with the upper surface of the pixel electrode 111G and the upper surface of the light-shielding layer 109. In addition, an end portion of the EL layer 113G preferably contacts the upper surface of the light-shielding layer 109. By providing the EL layer 113G not only on the pixel electrode 111G but also on the light-shielding layer 109, the area of ​​the EL layer 113G can be increased. This allows the area of ​​the light-emitting region of the light-emitting device 130G to be increased, resulting in a display device with a high aperture ratio.

[0179] An EL layer 113B is provided on the pixel electrode 111B and the light-shielding layer 109. The EL layer 113B preferably has regions in contact with the upper surface of the pixel electrode 111B and the upper surface of the light-shielding layer 109. In addition, an end portion of the EL layer 113B preferably contacts the upper surface of the light-shielding layer 109. By providing the EL layer 113B not only on the pixel electrode 111B but also on the light-shielding layer 109, the area of ​​the EL layer 113B can be increased. This allows the area of ​​the light-emitting region of the light-emitting device 130B to be increased, resulting in a display device with a high aperture ratio.

[0180] The pixel electrodes 111R, 111G, and 111B may each have a tapered end portion, which may improve the coverage of the layers (e.g., the light-shielding layer 109) provided on the pixel electrodes 111R, 111G, and 111B, and may prevent the light-shielding layer 109 from being porous and reducing its light-shielding properties.

[0181] The conductivity of the plugs 256R, 256G, and 256B is not particularly limited, and they can be, for example, an insulating layer, a semiconductor layer, or a conductive layer.

[0182] As described above, the thickness of the light-shielding layer 109 is preferably thick, and the height of the upper surface of the pixel electrode 111 is preferably higher than that of the light-shielding layer 109. Here, if the plug 256 is not provided and the height of the upper surface of the pixel electrode 111 is made higher than that of the light-shielding layer 109, the thickness of the pixel electrode 111 must be increased. However, for example, increasing the thickness of the pixel electrode 111 increases the stress of the conductive film that will become the pixel electrode 111, which reduces adhesion to the surface on which it is formed and may cause the conductive film to peel off. Furthermore, it may become difficult to process the conductive film into the pixel electrode 111. Furthermore, as the crystallinity of the conductive film increases, the surface irregularities of the conductive film increase, which may reduce the coverage of a layer (e.g., the EL layer 113R) provided on the pixel electrode 111.

[0183] The island-shaped EL layers 113R, 113G, and 113B can be formed, for example, by photolithography without using a fine metal mask. A film to become the EL layer 113R is formed, and the film is then processed by photolithography to form the island-shaped EL layer 113R. The same applies to the EL layers 113G and 113B. This allows the EL layers 113R, 113G, and 113B to be formed with fine sizes, resulting in a high-resolution display device. In a display device according to one embodiment of the present invention, the resolution can be, for example, 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20,000 ppi or less, or 30,000 ppi or less.

[0184] When using a fine metal mask, it is difficult to reduce the spacing between adjacent light-emitting devices to less than 10 μm. However, by using photolithography, the spacing between adjacent light-emitting devices, adjacent EL layers, or adjacent pixel electrodes can be reduced to, for example, less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, 1.5 μm or less, 1 μm or less, or 0.5 μm or less in processes on glass substrates. Furthermore, by using an exposure device for LSIs, the spacing between adjacent light-emitting devices, adjacent EL layers, or adjacent pixel electrodes can be reduced to, for example, 500 nm or less, 200 nm or less, 100 nm or less, or even 50 nm or less in processes on Si wafers. This significantly reduces the area of ​​the non-light-emitting region that may exist between two light-emitting devices, enabling the aperture ratio to approach 100%. For example, in a display device according to one embodiment of the present invention, the aperture ratio can be 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or even 90% or more, but less than 100%.

[0185] Increasing the aperture ratio of a display device can improve the reliability of the display device. More specifically, when the lifetime of a display device using an organic EL device and having an aperture ratio of 10% is taken as the reference, the lifetime of a display device having an aperture ratio of 20% (i.e., an aperture ratio twice as high as the reference) is approximately 3.25 times longer, and the lifetime of a display device having an aperture ratio of 40% (i.e., an aperture ratio four times as high as the reference) is approximately 10.6 times longer. Thus, as the aperture ratio increases, the current density flowing through the organic EL device required to obtain the same display can be reduced, thereby improving the lifetime of the display device. In a display device according to one embodiment of the present invention, the aperture ratio can be increased, thereby improving the display quality of the display device. Furthermore, as the aperture ratio of the display device increases, the reliability (especially the lifetime) of the display device is significantly improved, which is an excellent effect.

[0186] 4A to 8B , a mask layer 118R is located on the EL layer 113R of the light-emitting device 130R, a mask layer 118G is located on the EL layer 113G of the light-emitting device 130G, and a mask layer 118B is located on the EL layer 113B of the light-emitting device 130B. The mask layer 118B is a mask layer formed on the upper surface of the EL layer 113B during processing, with a portion of the mask layer remaining. Similarly, the mask layer 118G is a mask layer formed during the formation of the EL layer 113G, and the mask layer 118R is a mask layer formed during the formation of the EL layer 113R, with a portion of the mask layer remaining. In this manner, a display device according to one embodiment of the present invention can be configured such that a portion of the mask layer used to protect the EL layer during fabrication remains. The mask layers 118R, 118G, and 118B can be made of the same material or different materials. In the following, the mask layer 118R, the mask layer 118G, and the mask layer 118B may be collectively referred to as the mask layer 118.

[0187] One end of the mask layer 118R (the end opposite the light-emitting region, the outer end) is aligned or approximately aligned with the end of the EL layer 113R, and the other end of the mask layer 118R is located on the EL layer 113R. Preferably, the other end of the mask layer 118R (the end on the light-emitting region side, the inner end) overlaps the area where the EL layer 113R and the pixel electrode 111R contact each other. In this case, the other end of the mask layer 118R is easily formed on a substantially flat surface of the EL layer 113R. The same applies to the mask layers 118G and 118B. Furthermore, the mask layer 118 remains between the top surface of the EL layer (EL layer 113R, EL layer 113G, or EL layer 113B) processed into an island shape and the insulating layer 125. The mask layer will be described in detail in Embodiment 2.

[0188] The side surfaces of the EL layer 113R, the EL layer 113G, and the EL layer 113B are covered with the insulating layer 125. The insulating layer 127 overlaps the side surfaces of the EL layer 113R, the EL layer 113G, and the EL layer 113B with the insulating layer 125 interposed therebetween.

[0189] By covering part of the top surface and the side surfaces of the EL layers 113R, 113G, and 113B with at least one of the insulating layer 125, the insulating layer 127, and the mask layer 118, the common layer 114 (or the common electrode 115) is prevented from contacting the side surfaces of the EL layers 113R, 113G, and 113B, thereby preventing short circuits in the light-emitting device, thereby improving the reliability of the light-emitting device.

[0190] The EL layer preferably has a first region, which is a light-emitting region (also referred to as a light-emitting area), and a second region located outside the first region. The second region can also be referred to as a dummy region or a dummy area. The first region is located between the pixel electrode and the common electrode. The first region is covered with a mask layer 118 during the manufacturing process of the display device, and is therefore minimally damaged. Therefore, a light-emitting device with high light-emitting efficiency and a long lifetime can be realized. On the other hand, the second region includes the edge of the EL layer and its vicinity, and may be damaged by exposure to plasma during the manufacturing process of the display device. By not using the second region as a light-emitting region, variation in the characteristics of the light-emitting device can be suppressed. For example, by providing the EL layer also on the light-shielding layer 109, the portion in contact with the light-shielding layer 109 is included in the second region. This suppresses variation in the characteristics of the light-emitting device.

[0191] Although the structure in which the island-shaped EL layers 113R, 113G, and 113B are formed by photolithography has been described here, one embodiment of the present invention is not limited to this. For example, the island-shaped EL layers 113R, 113G, and 113B can also be formed by using a fine metal mask.

[0192] 2A to 8B, the EL layers 113R, 113G, and 113B are all shown with the same thickness, but this is not a limitation of one embodiment of the present invention. The EL layers 113R, 113G, and 113B may have different thicknesses. For example, it is preferable to set the thicknesses so that the optical path length increases the intensity of light emitted from the EL layers 113R, 113G, and 113B. This allows a microcavity structure to be realized, and the color purity of each light-emitting device can be improved.

[0193] The insulating layer 125 preferably contacts the side surfaces of the EL layer 113R, the EL layer 113G, and the EL layer 113B. By configuring the insulating layer 125 to contact the EL layer 113R, the EL layer 113G, and the EL layer 113B, peeling of the EL layer 113R, the EL layer 113G, and the EL layer 113B can be prevented. The insulating layer 125 is in close contact with the EL layer 113B, the EL layer 113G, or the EL layer 113R, thereby achieving the effect of fixing or bonding the adjacent EL layer 113B, etc., by the insulating layer 125. This can improve the reliability of the light-emitting device. Furthermore, the manufacturing yield of the light-emitting device can be increased.

[0194] 4A to 8B , the insulating layer 125 and the insulating layer 127 cover part of the top surface and both the side surfaces of the EL layer 113R, the EL layer 113G, and the EL layer 113B, which can further prevent the EL layers from peeling off, improve the reliability of the light-emitting device, and further increase the manufacturing yield of the light-emitting device.

[0195] The insulating layer 127 is provided on the insulating layer 125 so as to fill recesses formed in the insulating layer 125. The insulating layer 127 can be configured to overlap with part of the top surface and side surfaces of the EL layer 113R, the EL layer 113G, and the EL layer 113B via the insulating layer 125. The insulating layer 127 preferably covers at least part of the side surface of the insulating layer 125.

[0196] By providing the insulating layers 125 and 127, the gaps between adjacent island-shaped layers can be filled, which reduces large unevenness in height on the surface on which layers (e.g., a carrier injection layer, a common electrode, etc.) are formed on the island-shaped layers, thereby making the surface flatter, thereby improving the coverage of the carrier injection layer, the common electrode, etc.

[0197] The common layer 114 and the common electrode 115 are provided on the EL layer 113R, the EL layer 113G, the EL layer 113B, the mask layer 118, the insulating layer 125, and the insulating layer 127. Before the insulating layer 125 and the insulating layer 127 are provided, a step is generated between the region where the pixel electrode and the island-shaped EL layer are provided and the region where the pixel electrode and the island-shaped EL layer are not provided (the region between the light-emitting devices). The display device according to one embodiment of the present invention includes the insulating layer 125 and the insulating layer 127, which can flatten the step and improve the coverage of the common layer 114 and the common electrode 115. Therefore, poor connection due to disconnection can be suppressed. Furthermore, the step can be suppressed from locally thinning the common electrode 115, which can increase electrical resistance.

[0198] The upper surface of the insulating layer 127 preferably has a highly flat shape, but may also have a convex portion, a convex curved surface, a concave curved surface, or a concave portion. For example, the upper surface of the insulating layer 127 preferably has a highly flat convex curved surface with a large radius of curvature.

[0199] Next, examples of materials for the insulating layer 125 and the insulating layer 127 will be described.

[0200] The insulating layer 125 can be an insulating layer containing an inorganic material. For example, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film can be used for the insulating layer 125. The insulating layer 125 can have a single-layer structure or a stacked-layer structure. Examples of oxide insulating films include a silicon oxide film, an aluminum oxide film, a magnesium oxide film, an indium gallium zinc oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of nitride insulating films include a silicon nitride film and an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film and an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film and an aluminum nitride oxide film. In particular, aluminum oxide is preferable because it has a high etching selectivity with respect to the EL layer and has a function of protecting the EL layer in the formation of the insulating layer 127 described later. In particular, by using an inorganic insulating film such as an aluminum oxide film, a hafnium oxide film, or a silicon oxide film formed by atomic layer deposition (ALD) as the insulating layer 125, it is possible to form an insulating layer 125 that has few pinholes and has an excellent function of protecting the EL layer. The insulating layer 125 may also have a stacked structure of a film formed by ALD and a film formed by sputtering. For example, the insulating layer 125 may have a stacked structure of an aluminum oxide film formed by ALD and a silicon nitride film formed by sputtering.

[0201] The insulating layer 125 preferably functions as a barrier insulating layer against at least one of water and oxygen. The insulating layer 125 preferably has a function of suppressing diffusion of at least one of water and oxygen. The insulating layer 125 preferably has a function of capturing or fixing (also referred to as gettering) at least one of water and oxygen.

[0202] In this specification and the like, a barrier insulating layer refers to an insulating layer having barrier properties. Furthermore, in this specification and the like, the barrier properties refer to a function of making it difficult for a target substance to diffuse, thereby suppressing the permeation of the substance through the film (also referred to as low permeability), or a function of capturing or fixing (also referred to as gettering) the target substance.

[0203] The insulating layer 125 has a function as a barrier insulating layer or a gettering function, which makes it possible to suppress the intrusion of impurities (typically, at least one of water and oxygen) that may diffuse into each light-emitting device from the outside. With this configuration, it is possible to provide a highly reliable light-emitting device and further a highly reliable display device.

[0204] The insulating layer 125 preferably has a low impurity concentration. This can prevent impurities from entering the EL layer from the insulating layer 125 and causing deterioration of the EL layer. Furthermore, by reducing the impurity concentration in the insulating layer 125, the barrier properties against at least one of water and oxygen can be improved. For example, it is desirable that the insulating layer 125 has a sufficiently low hydrogen concentration or a sufficiently low carbon concentration, or preferably both of them.

[0205] The same material can be used for the insulating layer 125 and the mask layers 118B, 118G, and 118R. In this case, the boundary between the insulating layer 125 and any of the mask layers 118B, 118G, and 118R may be unclear. Therefore, the insulating layer 125 and any of the mask layers 118B, 118G, and 118R may be recognized as a single layer. In other words, one layer may be provided in contact with a portion of the top surface and the side surface of each of the EL layers 113R, 113G, and 113B, and the insulating layer 127 may be observed to cover at least a portion of the side surface of the single layer.

[0206] The insulating layer 127 provided on the insulating layer 125 has the function of flattening large unevenness of the insulating layer 125 formed between adjacent light-emitting devices. In other words, the insulating layer 127 has the effect of improving the flatness of the surface on which the common electrode 115 is formed.

[0207] An insulating layer containing an organic material can be suitably used as the insulating layer 127. A photosensitive resin, for example, a photosensitive resin composition containing an acrylic resin, can be preferably used as the organic material. The insulating layer 127 can be made of any of the materials listed for the plugs 256R, 256G, and 256B.

[0208] The insulating layer 127 can also be made of a material that absorbs visible light. By having the insulating layer 127 absorb light emitted from the light-emitting device, it is possible to prevent light from leaking from the light-emitting device to an adjacent light-emitting device through the insulating layer 127. This can improve the display quality of the display device. Furthermore, since the display quality can be improved without using a polarizing plate in the display device, it is possible to reduce the weight and thickness of the display device. The insulating layer 127 can also be made of a material that can be used for the light-shielding layer 109.

[0209] A mask layer 118R is provided in contact with a portion of the upper surface of the EL layer 113R, a mask layer 118G is provided in contact with a portion of the upper surface of the EL layer 113G, and a mask layer 118B is provided in contact with a portion of the upper surface of the EL layer 113B. An insulating layer 125 is provided in contact with the upper and side surfaces of the mask layer 118R, the upper and side surfaces of the mask layer 118G, the upper and side surfaces of the mask layer 118B, and the upper surface of the light-shielding layer 109. An insulating layer 127 is provided in contact with the upper and side surfaces of the insulating layer 125. Furthermore, the insulating layer 127 overlaps, via the insulating layer 125, with a portion of the upper surface and side surfaces of the EL layer 113R, a portion of the upper surface and side surfaces of the EL layer 113G, and a portion of the upper surface and side surfaces of the EL layer 113B. A common layer 114 is provided to cover the EL layer 113R, the mask layer 118R, the EL layer 113G, the mask layer 118G, the EL layer 113B, the mask layer 118B, the insulating layer 125, and the insulating layer 127, and a common electrode 115 is provided on the common layer 114.

[0210] The insulating layer 127 is formed in a region between two island-shaped EL layers (for example, a region between the EL layer 113R and the EL layer 113G). At this time, at least a portion of the insulating layer 127 is located between adjacent EL layers. The provision of the insulating layer 127 improves coverage of the common layer 114 and the common electrode 115 formed on the island-shaped EL layers and the insulating layer 127, thereby preventing these layers from being separated and from having locally thin portions.

[0211] In a cross-sectional view, the upper surface of the insulating layer 127 preferably has a convex curved shape. The convex curved shape of the upper surface of the insulating layer 127 preferably has a shape that bulges gently toward the center. Furthermore, it is preferable that the convex curved portion in the center of the upper surface of the insulating layer 127 has a shape that is continuously connected toward the edge. By forming the insulating layer 127 in this shape, the common layer 114 and the common electrode 115 can be formed with high coverage over the entire insulating layer 127.

[0212] By providing the insulating layers 127 and 125, the common layer 114 and the common electrode 115 can be formed with high coverage. Furthermore, it is possible to prevent the common layer 114 and the common electrode 115 from being divided and from being locally thin. Therefore, it is possible to prevent poor connection between the light-emitting devices in the common layer 114 and the common electrode 115 due to the divided portions and an increase in electrical resistance due to the locally thin portions. This allows the display device according to one embodiment of the present invention to have improved display quality.

[0213] It is preferable to provide a protective layer 131 on the light emitting device 130R, the light emitting device 130G, and the light emitting device 130B. The reliability of the light emitting device can be improved by providing the protective layer 131. The protective layer 131 can have a single layer structure or a multilayer structure.

[0214] There is no limitation on the conductivity of the protective layer 131. The protective layer 131 can be formed using at least one of an insulating film, a semiconductor film, and a conductive film.

[0215] The protective layer 131 has an inorganic film, which prevents the common electrode 115 from being oxidized, suppresses impurities (moisture, oxygen, etc.) from entering the light-emitting device, and suppresses deterioration of the light-emitting device, thereby improving the reliability of the display device.

[0216] For the protective layer 131, for example, an inorganic insulating film such as an insulating oxide film, an insulating nitride film, an insulating oxynitride film, or an insulating nitride oxide film can be used. Specific examples of these inorganic insulating films are as given in the description of the insulating layer 125. In particular, the protective layer 131 preferably has an insulating nitride film or an insulating nitride oxide film, and more preferably has an insulating nitride film.

[0217] The protective layer 131 may be formed using an inorganic film containing In—Sn oxide (ITO), In—Zn oxide, Ga—Zn oxide, Al—Zn oxide, indium gallium zinc oxide (In—Ga—Zn oxide, also referred to as IGZO), or the like. The inorganic film preferably has high resistance, specifically, preferably has higher resistance than the common electrode 115. The inorganic film may further contain nitrogen.

[0218] When light emitted from the light-emitting device is extracted through the protective layer 131, it is preferable that the protective layer 131 has high transparency to visible light. For example, ITO, IGZO, and aluminum oxide are preferable because they are inorganic materials that have high transparency to visible light.

[0219] For example, a stacked structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a stacked structure of an aluminum oxide film and an IGZO film on the aluminum oxide film can be used as the protective layer 131. By using such a stacked structure, impurities (water, oxygen, etc.) can be prevented from entering the EL layer side.

[0220] Furthermore, the protective layer 131 may have an organic film. For example, the protective layer 131 may have both an organic film and an inorganic film. Examples of organic materials that can be used for the protective layer 131 include the organic insulating materials that can be used for the insulating layer 127.

[0221] The protective layer 131 may have a two-layer structure formed by using different film formation methods. Specifically, the first layer of the protective layer 131 may be formed by the ALD method, and the second layer of the protective layer 131 may be formed by the sputtering method.

[0222] Various optical members can be disposed on the outside of the substrate 120. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light-collecting film. In addition, a surface protection layer such as an anti-static film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses the occurrence of scratches during use, or an impact absorbing layer may be disposed on the outside of the substrate 120. For example, a glass layer or a silica layer (SiO ｘ The surface protection layer can be preferably formed of a material such as DLC (diamond-like carbon), aluminum oxide (AlO ｘ ), polyester-based materials, or polycarbonate-based materials may also be used. Note that it is preferable to use a material with high transmittance to visible light for the surface protection layer. It is also preferable to use a material with high hardness for the surface protection layer.

[0223] The substrate 120 can be a glass substrate, a quartz substrate, a ceramic substrate, a sapphire substrate, a resin substrate, a metal substrate, an alloy substrate, a semiconductor substrate, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting device is extracted. Using a flexible material for the substrate 120 can increase the flexibility of the display device and realize a flexible display. A polarizing plate may also be used as the substrate 120.

[0224] When a circularly polarizing plate is superimposed on a display device, it is preferable that the display device has a substrate with high optical isotropy. A substrate with high optical isotropy has small birefringence (or a small amount of birefringence).

[0225] The absolute value of the retardation (phase difference) of a substrate having high optical isotropy is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0226] Examples of films with high optical isotropy include triacetyl cellulose (TAC, also known as cellulose triacetate) films, cycloolefin polymer (COP) films, cycloolefin copolymer (COC) films, and acrylic films.

[0227] When a film is used as a substrate, the film may absorb water, which may cause changes in shape, such as wrinkles, in the display device. Therefore, it is preferable to use a film with low water absorption as the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferably 0.1% or less, and even more preferably 0.01% or less.

[0228] The resin layer 122 can be made of various curable adhesives, such as a photo-curable adhesive (e.g., an ultraviolet-curable adhesive), a reactive curable adhesive, a thermosetting adhesive, or an anaerobic adhesive. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. Materials with low moisture permeability, such as epoxy resin, are particularly preferred. Two-component resins may also be used. Adhesive sheets or the like may also be used.

[0229] 9A to 9D are cross-sectional views taken along dashed line Y1-Y2 in FIG. 1A . FIGS. 9A to 9D show the connection portion 140 and its vicinity. The common layer 114 and the common electrode 115 are shared by the light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B. As shown in FIG. 9A , the common layer 114 and the common electrode 115 are electrically connected to a conductive layer 123 provided in the connection portion 140. The conductive layer 123 can be formed, for example, in the same process as the pixel electrodes 111R, 111G, and 111B.

[0230] 9B , a configuration may be used in which the common electrode 115 is in contact with the conductive layer 123 without the common layer 114. For example, by using a mask for defining a film formation area (also called an area mask or a rough metal mask to distinguish it from a fine metal mask), the region where the common layer 114 is formed can be controlled, and therefore it is also possible to configure the common layer 114 not to be formed on the connection portion 140.

[0231] Similarly, by using a mask to define the film formation area, the common electrode 115 can be configured not to be formed on the connection portion 140. That is, in FIG. 9B , a configuration can be achieved in which only the common layer 114, instead of the common electrode 115, is in contact with the conductive layer 123.

[0232] A conductive layer 250p is provided on the substrate 103. The conductive layer 250p can be formed, for example, in the same process as the conductive layer 250. A conductive layer 123 is provided on the conductive layer 250p. A plug 256p is provided between the conductive layer 250p and the conductive layer 123. The plug 256p can be formed, for example, in the same process as the plug 256.

[0233] 9A to 9D correspond to cross-sectional views of the connection portion 140, and show a configuration in which the light-shielding layer 109 is also provided in the connection portion 140. Note that if no transistor is provided in the connection portion 140, the light-shielding layer 109 may not be provided. In that case, the connection portion 140 has a configuration in which the light-shielding layer 109 is removed from the configuration in FIGS. 9A to 9D.

[0234] Fig. 9C shows a configuration in which the light-shielding layer 109 in Fig. 9A is provided in a recess in the insulating layer 104. The other configurations are the same as those in Fig. 9A, and therefore descriptions thereof will be omitted. Fig. 9D shows a configuration in which the light-shielding layer 109 in Fig. 9B is provided in a recess in the insulating layer 104. The other configurations are the same as those in Fig. 9B, and therefore descriptions thereof will be omitted.

[0235] The configuration of the connection section 140 shown here can also be applied to other display devices.

[0236] [Specific Example 2] A modification of Fig. 3B is shown in Fig. 10A, and an enlarged view of light-emitting device 130R and its vicinity is shown in Fig. 10B.

[0237] The display device 100 shown in Fig. 10A has conductive layers 137R, 137G, and 137B, as shown in Fig. 3D. The conductive layers 137R, 137G, and 137B may be collectively referred to as conductive layer 137. The conductive layer 137 preferably has a region extending from the edge of the pixel electrode and an extended end. The extended region preferably overlaps with the light-shielding layer 109. Note that the connection portion 140 also preferably has a conductive layer formed in the same process as the conductive layer 137.

[0238] The light-emitting device 130R has a conductive layer 137R between the pixel electrode 111R and the EL layer 113R. The light-emitting device 130R has a pixel electrode 111R, a conductive layer 137R on the pixel electrode 111R, an island-shaped EL layer 113R on the conductive layer 137R, a common layer 114 on the EL layer 113R, and a common electrode 115 on the common layer 114.

[0239] The light-emitting devices 130G and 130B have the same configuration as the light-emitting device 130A. Specifically, the light-emitting device 130G has a conductive layer 135G between the pixel electrode 111G and the EL layer 113G. Furthermore, the light-emitting device 130B has a conductive layer 135B between the pixel electrode 111B and the EL layer 113B.

[0240] The conductive layer 137R, the conductive layer 137G, and the conductive layer 137B can be formed in the same process, for example.

[0241] Each of the conductive layers 137R, 137G, and 137B preferably has a region in contact with the upper surface of the light-shielding layer 109. An end of the conductive layer 137R, an end of the conductive layer 137G, and an end of the conductive layer 137B preferably contact the upper surface of the light-shielding layer 109.

[0242] The insulating layer 125 has regions in contact with the side surfaces of the conductive layer 137R, the side surfaces of the conductive layer 137G, the side surfaces of the conductive layer 137B, the side surfaces of the EL layer 113R, the side surfaces of the EL layer 113G, the side surfaces of the EL layer 113B, the side surfaces and top surfaces of the mask layer 118R, the side surfaces and top surfaces of the mask layer 118G, the side surfaces and top surfaces of the mask layer 118B, and the top surface of the light-shielding layer 109.

[0243] The conductive films that will become the conductive layers 137R, 137G, and 137B can function as etching stoppers when forming the EL layers 113R, 113G, and 113B, and the mask layers 118R, 118G, and 118B. The conductive films that will become the conductive layers 137R, 137G, and 137B may be referred to as first etching stoppers. For example, the first etching stoppers are formed on the light-shielding layer 109, the pixel electrodes 111R, 111G, and 111B. A film that will become the EL layer 113R and a mask film that will become the mask layer 118R are formed on the first etching stopper, and the film and the mask film are processed using photolithography to form the EL layer 113R and the mask layer 118R. When the EL layer 113R and the mask layer 118R are formed, the light-shielding layer 109 is covered with the first etching stopper, so that the light-shielding layer 109 is etched, and the thickness of the light-shielding layer 109 is prevented from becoming thin. This improves the light-shielding properties of the light-shielding layer 109. Similarly, when the EL layer 113B and the mask layer 118B are formed, and when the EL layer 113B and the mask layer 118B are formed, the first etching stopper prevents the thickness of the light-shielding layer 109 from becoming thin.

[0244] After forming the EL layer 113R, mask layer 118R, EL layer 113G, mask layer 118G, EL layer 113B, and mask layer 118B, a first etching stopper is processed using these as a mask, and conductive layer 137R, conductive layer 137G, and conductive layer 137B can be formed. This allows the edge of conductive layer 137R to coincide or approximately coincide with the edge of EL layer 113R. Similarly, the edge of conductive layer 137G can coincide or approximately coincide with the edge of EL layer 113G. The edge of conductive layer 137B can coincide or approximately coincide with the edge of EL layer 113B.

[0245] For the conductive layers 137R, 137G, and 137B, it is preferable to use a material that has high resistance in forming the EL layers 113R, 113G, and 113B, specifically, a material that has a high etching selectivity with respect to the EL layers 113R, 113G, and 113B. Dry etching or wet etching can be used to form the EL layers 113R, 113G, and 113B. In particular, anisotropic dry etching can be preferably used.

[0246] In forming the EL layers 113R, 113G, and 113B, it is preferable to set the thicknesses of the conductive layers 137R, 137G, and 137B so that the conductive films (first etching stoppers) that become the conductive layers 137R, 137G, and 137B cover the light-shielding layer 109 and do not expose the light-shielding layer 109. Here, if the conductive layers 137R, 137G, and 137B are too thin, their function as etching stoppers will be reduced, and if they are too thick, the productivity of the display device may be reduced.

[0247] 10B , the thickness T137 of the conductive layer 137R can be the shortest distance between the surface on which the conductive layer 137R is formed (here, the upper surface of the pixel electrode 111R in the region where the conductive layer 137R and the pixel electrode 111R contact each other) and the upper surface of the conductive layer 137R in the cross-sectional view. The thickness T137 is preferably 5 nm to 100 nm, more preferably 10 nm to 100 nm, even more preferably 10 nm to 60 nm, even more preferably 20 nm to 60 nm, and even more preferably 20 nm to 40 nm. By setting the thickness T137 within the above-mentioned range, it is possible to prevent the thickness of the light-shielding layer 109 from becoming thin and to improve the productivity of the display device. Note that the thickness T137 is not limited to the above-mentioned range.

[0248] The conductive layer 137R, the conductive layer 137G, and the conductive layer 137B can be formed using, for example, an oxide conductor. The above-described materials can be used as the oxide conductor. The conductive layer 137R, the conductive layer 137G, and the conductive layer 137B can be formed using, for example, one or more of In—Sn oxide (ITO), In—Si—Sn oxide (ITSO), In—Zn oxide (IZO (registered trademark)), In—Ga—Zn oxide (IGZO), and In—Sn—Zn oxide (ITZO (registered trademark)).

[0249] The conductive layers 137R, 137G, and 137B are preferably made of a material that is transparent to visible light. The pixel electrodes 111R, 111G, and 111B are preferably made of a material that is reflective to visible light. The conductive layers 137R, 137G, and 137B function as transmissive electrodes, while the pixel electrodes 111R, 111G, and 111B function as reflective electrodes. Furthermore, the common electrode 115 preferably functions as a semi-transmissive / semi-reflective electrode. This allows the light-emitting device to have a micro-optical resonator (microcavity) structure, causing light from the light-emitting layer to resonate between the two electrodes, thereby enhancing the light emitted from the light-emitting device. The conductive layers 137R, 137G, and 137B can be said to function as optical adjustment layers. In this case, it is preferable to set the thickness of these conductive layers so that the optical path length is such that the light emitted by the EL layers 113R, 113G, and 113B is intensified.

[0250] For example, the pixel electrode 111R, the pixel electrode 111G, and the pixel electrode 111B can each have a stacked structure of a first titanium film, an aluminum film on the first titanium film, and a second titanium film on the aluminum film. The conductive layer 137R, the conductive layer 137G, and the conductive layer 137B can each have a single-layer structure of an ITSO film. An aluminum film has high light reflectivity and is suitable as a reflective electrode. On the other hand, if an aluminum film comes into contact with an oxide conductor film (e.g., an ITSO film), electrolytic corrosion may occur. Therefore, it is preferable to provide a titanium film between the aluminum film and the oxide conductor film.

[0251] Note that the structures of the conductive layer 137R, the conductive layer 137G, and the conductive layer 137B shown here can also be applied to other display devices.

[0252] [Specific Example 3] A modification of Fig. 3B is shown in Fig. 11A, and an enlarged view of light-emitting device 130R and its vicinity is shown in Fig. 11B.

[0253] The display device 100 shown in Figure 11A is characterized by providing a conductive layer 135R on the pixel electrode 111R, a conductive layer 135G on the pixel electrode 111G, and a conductive layer 135B on the pixel electrode 111B. The conductive layers 135R, 135G, and 135B are sometimes collectively referred to as conductive layer 135. Unlike the conductive layer 137 in Figures 10A and 10B, it is preferable that the end of the conductive layer 135 in Figures 11A and 11B coincide or approximately coincide with the pixel electrode 111. It is also preferable that the connection portion 140 has a conductive layer formed in the same process as the conductive layer 135.

[0254] The light-emitting device 130R has a conductive layer 135R between the pixel electrode 111R and the EL layer 113R. The conductive layer 135R can be made of the same conductive material as the conductive layer 137R. However, the conductive layer 135R is processed in the same process as the pixel electrode 111R, and it is preferable that the edge of the conductive layer 135R has an area that coincides with the edge of the pixel electrode 111R in a cross-sectional view. The light-emitting device 130R has the pixel electrode 111R, the conductive layer 135R on the pixel electrode 111R, an island-shaped EL layer 113R on the conductive layer 135R, a common layer 114 on the EL layer 113R, and a common electrode 115 on the common layer 114.

[0255] The light-emitting devices 130G and 130B have the same configuration as the light-emitting device 130A. Specifically, the light-emitting device 130G has a conductive layer 135G between the pixel electrode 111G and the EL layer 113G. Furthermore, the light-emitting device 130B has a conductive layer 135B between the pixel electrode 111B and the EL layer 113B.

[0256] The conductive layer 135R, the conductive layer 135G, and the conductive layer 135B can be formed in the same process, for example.

[0257] It is preferable that the conductive layer 135R, the conductive layer 135G, and the conductive layer 135B do not contact the upper surface of the light-shielding layer 109. It is preferable that the end of the conductive layer 135R, the end of the conductive layer 135G, and the end of the conductive layer 135B do not contact the upper surface of the light-shielding layer 109.

[0258] The insulating layer 125 does not contact the side surfaces of the conductive layer 135R, the side surfaces of the conductive layer 135G, or the side surfaces of the conductive layer 135B, but has regions that contact the side surfaces of the EL layer 113R, the side surfaces of the EL layer 113G, the side surfaces of the EL layer 113B, the side surfaces and top surfaces of the mask layer 118R, the side surfaces and top surfaces of the mask layer 118G, the side surfaces and top surfaces of the mask layer 118B, and the top surface of the light-shielding layer 109.

[0259] The conductive films that become the conductive layers 135R, 135G, and 135B can function as optical adjustment layers.

[0260] 11B , the thickness T135 of the conductive layer 135R can be the shortest distance between the surface on which the conductive layer 135R is formed in the cross-sectional view (here, the upper surface of the pixel electrode 111R in the region where the conductive layer 135R and the pixel electrode 111R contact each other) and the upper surface of the conductive layer 135R. The thickness T135 is preferably 5 nm to 100 nm, more preferably 10 nm to 100 nm, even more preferably 10 nm to 60 nm, even more preferably 20 nm to 60 nm, and even more preferably 20 nm to 40 nm. By setting the thickness T135 within the aforementioned range, it is possible to prevent the thickness of the light-shielding layer 109 from becoming thin and to improve the productivity of the display device. Note that the thickness T135 is not limited to the aforementioned range.

[0261] The conductive layer 135R, the conductive layer 135G, and the conductive layer 135B can be formed using, for example, an oxide conductor. The above-mentioned materials can be used as the oxide conductor. The conductive layer 135R, the conductive layer 135G, and the conductive layer 135B can be formed using, for example, one or more of In—Sn oxide (ITO), In—Si—Sn oxide (ITSO), In—Zn oxide (IZO (registered trademark)), In—Ga—Zn oxide (IGZO), and In—Sn—Zn oxide (ITZO (registered trademark)).

[0262] The conductive layers 135R, 135G, and 135B are preferably made of a material that is transparent to visible light. The pixel electrodes 111R, 111G, and 111B are preferably made of a material that is reflective to visible light. The conductive layers 135R, 135G, and 135B function as transmissive electrodes, while the pixel electrodes 111R, 111G, and 111B function as reflective electrodes. Furthermore, the common electrode 115 preferably functions as a semi-transmissive / semi-reflective electrode. This allows the light-emitting device to have a micro-optical resonator (microcavity) structure, causing light from the light-emitting layer to resonate between the two electrodes, thereby enhancing the light emitted from the light-emitting device. The conductive layers 135R, 135G, and 135B can be said to function as optical adjustment layers. In this case, it is preferable to set the thickness of these conductive layers so that the optical path length is such that the light emitted by the EL layers 113R, 113G, and 113B is intensified.

[0263] For example, the pixel electrode 111R, the pixel electrode 111G, and the pixel electrode 111B can each have a stacked structure of a first titanium film, an aluminum film on the first titanium film, and a second titanium film on the aluminum film. The conductive layer 135R, the conductive layer 135G, and the conductive layer 135B can each have a single-layer structure of an ITSO film. An aluminum film has high light reflectivity and is suitable as a reflective electrode. On the other hand, if an aluminum film comes into contact with an oxide conductor film (e.g., an ITSO film), electrolytic corrosion may occur. Therefore, it is preferable to provide a titanium film between the aluminum film and the oxide conductor film.

[0264] The configurations of the conductive layer 135R, the conductive layer 135G, and the conductive layer 135B shown here can also be applied to other display devices.

[0265] [Specific Example 4] A modification of Fig. 3B is shown in Fig. 12A. An enlarged view of light-emitting device 130R and its vicinity is shown in Fig. 12B. Display device 100 shown in Figs. 12A and 12B is characterized by having conductive layer 137 of specific example 2 and conductive layer 135 of specific example 3.

[0266] Note that the connection portion 140 also preferably has a conductive layer formed in the same process as the conductive layer 135. Furthermore, the connection portion 140 also preferably has a conductive layer formed in the same process as the conductive layer 137.

[0267] The light-emitting device 130R has a conductive layer 135R and a conductive layer 137R between the pixel electrode 111R and the EL layer 113R. However, the conductive layer 135R is processed in the same process as the pixel electrode 111R, and it is preferable that an edge of the conductive layer 135R has an area that coincides with an edge of the pixel electrode 111R in a cross-sectional view. The light-emitting device 130R has the pixel electrode 111R, a conductive layer 135R on the pixel electrode 111R, a conductive layer 137R on the conductive layer 135R, an island-shaped EL layer 113R on the conductive layer 137R, a common layer 114 on the EL layer 113R, and a common electrode 115 on the common layer 114.

[0268] The light-emitting devices 130G and 130B have the same configuration as the light-emitting device 130A. Specifically, the light-emitting device 130G has a conductive layer 135G and a conductive layer 137G between the pixel electrode 111G and the EL layer 113G. Furthermore, the light-emitting device 130B has a conductive layer 135B and a conductive layer 137B between the pixel electrode 111B and the EL layer 113B.

[0269] The conductive layer 135R, the conductive layer 135G, and the conductive layer 135B can be formed, for example, in the same process. The conductive layer 137R, the conductive layer 137G, and the conductive layer 137B can be formed, for example, in the same process.

[0270] As shown in FIG. 12B , the thickness T135 of the conductive layer 135R can be the shortest distance between the surface on which the conductive layer 135R is formed (here, the upper surface of the pixel electrode 111R in the region where the conductive layer 135R and the pixel electrode 111R contact each other) and the upper surface of the conductive layer 135R in the cross-sectional view. The thickness T135 is preferably 5 nm to 100 nm, more preferably 10 nm to 100 nm, even more preferably 10 nm to 60 nm, even more preferably 20 nm to 60 nm, and even more preferably 20 nm to 40 nm. By setting the thickness T135 within the aforementioned range, it is possible to prevent the thickness of the light-shielding layer 109 from becoming thin and to improve the productivity of the display device. Note that the thickness T135 is not limited to the aforementioned range.

[0271] The conductive layer 135R, the conductive layer 135G, and the conductive layer 135B can be formed using, for example, an oxide conductor. The above-mentioned materials can be used as the oxide conductor. The conductive layer 135R, the conductive layer 135G, and the conductive layer 135B can be formed using, for example, one or more of In—Sn oxide (ITO), In—Si—Sn oxide (ITSO), In—Zn oxide (IZO (registered trademark)), In—Ga—Zn oxide (IGZO), and In—Sn—Zn oxide (ITZO (registered trademark)).

[0272] The conductive layers 135R, 135G, and 135B are preferably made of a material that is transparent to visible light. The pixel electrodes 111R, 111G, and 111B are preferably made of a material that is reflective to visible light. The conductive layers 135R, 135G, and 135B function as transmissive electrodes, while the pixel electrodes 111R, 111G, and 111B function as reflective electrodes. Furthermore, the common electrode 115 preferably functions as a semi-transmissive / semi-reflective electrode. This allows the light-emitting device to have a micro-optical resonator (microcavity) structure, causing light from the light-emitting layer to resonate between the two electrodes, thereby enhancing the light emitted from the light-emitting device. The conductive layers 135R, 135G, and 135B can be said to function as optical adjustment layers. In this case, it is preferable to set the thickness of these conductive layers so that the optical path length is such that the light emitted by the EL layers 113R, 113G, and 113B is intensified.

[0273] For example, the pixel electrode 111R, the pixel electrode 111G, and the pixel electrode 111B can each have a stacked structure of a first titanium film, an aluminum film on the first titanium film, and a second titanium film on the aluminum film. The conductive layer 135R, the conductive layer 135G, and the conductive layer 135B can each have a single-layer structure of an ITSO film. An aluminum film has high light reflectivity and is suitable as a reflective electrode. On the other hand, if an aluminum film comes into contact with an oxide conductor film (e.g., an ITSO film), electrolytic corrosion may occur. Therefore, it is preferable to provide a titanium film between the aluminum film and the oxide conductor film.

[0274] The configurations of the conductive layer 135R, the conductive layer 135G, and the conductive layer 135B shown here can also be applied to other configuration examples.

[0275] The conductive films that will become the conductive layers 137R, 137G, and 137B can function as etching stoppers when forming the EL layers 113R, 113G, and 113B, and the mask layers 118R, 118G, and 118B. The conductive films that will become the conductive layers 137R, 137G, and 137B may be referred to as first etching stoppers. For example, the first etching stoppers are formed on the light-shielding layer 109, the pixel electrodes 111R, 111G, and 111B. A film that will become the EL layer 113R and a mask film that will become the mask layer 118R are formed on the first etching stopper, and the film and the mask film are processed using photolithography to form the EL layer 113R and the mask layer 118R. When the EL layer 113R and the mask layer 118R are formed, the light-shielding layer 109 is covered with the first etching stopper, so that the light-shielding layer 109 is etched, and the thickness of the light-shielding layer 109 is prevented from becoming thin. This improves the light-shielding properties of the light-shielding layer 109. Similarly, when the EL layer 113B and the mask layer 118B are formed, and when the EL layer 113B and the mask layer 118B are formed, the first etching stopper prevents the thickness of the light-shielding layer 109 from becoming thin.

[0276] After forming the EL layer 113R, mask layer 118R, EL layer 113G, mask layer 118G, EL layer 113B, and mask layer 118B, a first etching stopper is processed using these as a mask, and conductive layer 137R, conductive layer 137G, and conductive layer 137B can be formed. This allows the edge of conductive layer 137R to coincide or approximately coincide with the edge of EL layer 113R. Similarly, the edge of conductive layer 137G can coincide or approximately coincide with the edge of EL layer 113G. The edge of conductive layer 137B can coincide or approximately coincide with the edge of EL layer 113B.

[0277] For the conductive layers 137R, 137G, and 137B, it is preferable to use a material that has high resistance in forming the EL layers 113R, 113G, and 113B, specifically, a material that has a high etching selectivity with respect to the EL layers 113R, 113G, and 113B. Dry etching or wet etching can be used to form the EL layers 113R, 113G, and 113B. In particular, anisotropic dry etching can be preferably used.

[0278] In forming the EL layers 113R, 113G, and 113B, it is preferable to set the thicknesses of the conductive layers 137R, 137G, and 137B so that the conductive films (first etching stoppers) that will become the conductive layers 137R, 137G, and 137B cover the light-shielding layer 109 and prevent the light-shielding layer 109 from being exposed. Here, if the conductive layers 137R, 137G, and 137B are too thin, their function as etching stoppers may be reduced, while if they are too thick, productivity of the display device may be reduced. As shown in FIG. 12B , the thickness T137 of the conductive layer 137R can be set to the shortest distance between the surface on which the conductive layer 137R is formed in the cross-sectional view (here, the upper surface of the pixel electrode 111R in the region where the conductive layer 137R and the pixel electrode 111R contact each other) and the upper surface of the conductive layer 137R. The thickness T137 is preferably 5 nm or more and 100 nm or less, more preferably 10 nm or more and 100 nm or less, even more preferably 10 nm or more and 60 nm or less, even more preferably 20 nm or more and 60 nm or less, and even more preferably 20 nm or more and 40 nm or less. By setting the thickness T137 within the above range, it is possible to prevent the thickness of the light-shielding layer 109 from becoming thin and to improve the productivity of the display device. Note that the thickness T137 is not limited to the above range.

[0279] The conductive layer 137R, the conductive layer 137G, and the conductive layer 137B can be formed using, for example, an oxide conductor. The above-described materials can be used as the oxide conductor. The conductive layer 137R, the conductive layer 137G, and the conductive layer 137B can be formed using, for example, one or more of In—Sn oxide (ITO), In—Si—Sn oxide (ITSO), In—Zn oxide (IZO (registered trademark)), In—Ga—Zn oxide (IGZO), and In—Sn—Zn oxide (ITZO (registered trademark)).

[0280] The conductive layers 137R, 137G, and 137B are preferably made of a material that is transparent to visible light. The pixel electrodes 111R, 111G, and 111B are preferably made of a material that is reflective to visible light. The conductive layers 137R, 137G, and 137B function as transmissive electrodes, while the pixel electrodes 111R, 111G, and 111B function as reflective electrodes. Furthermore, the common electrode 115 preferably functions as a semi-transmissive / semi-reflective electrode. This allows the light-emitting device to have a micro-optical resonator (microcavity) structure, causing light from the light-emitting layer to resonate between the two electrodes, thereby enhancing the light emitted from the light-emitting device. The conductive layers 137R, 137G, and 137B can be said to function as optical adjustment layers. In this case, it is preferable to set the thickness of these conductive layers so that the optical path length is such that the light emitted by the EL layers 113R, 113G, and 113B is intensified.

[0281] For example, the pixel electrode 111R, the pixel electrode 111G, and the pixel electrode 111B can each have a stacked structure of a first titanium film, an aluminum film on the first titanium film, and a second titanium film on the aluminum film. The conductive layer 137R, the conductive layer 137G, and the conductive layer 137B can each have a single-layer structure of an ITSO film. An aluminum film has high light reflectivity and is suitable as a reflective electrode. On the other hand, if an aluminum film comes into contact with an oxide conductor film (e.g., an ITSO film), electrolytic corrosion may occur. Therefore, it is preferable to provide a titanium film between the aluminum film and the oxide conductor film.

[0282] Note that the structures of the conductive layer 135R, the conductive layer 135G, the conductive layer 135B, the conductive layer 137R, the conductive layer 137G, and the conductive layer 137B shown here can also be applied to other display devices.

[0283] [Specific Example 5] A modification of Fig. 3B is shown in Fig. 13A. An enlarged view of a light-emitting device 130R and its vicinity is shown in Fig. 13B. In Fig. 13A and Fig. 13B, a feature is that an upper portion (109u) of the light-shielding layer 109 in the cross-sectional view has a tapered shape.

[0284] Since the end of the pixel electrode 111R has a tapered shape, it is preferable that the end of the region corresponding to the upper part (109u) of the light-shielding layer 109 also has a tapered shape. It is also preferable that the end of the conductive layer 135R has a tapered shape, and that the tapered shape is continuous with the end of the pixel electrode 111R.

[0285] The lower portion (109b) of the light-shielding layer 109 has the same shape as the side surface of the recess in the insulating layer 104. That is, if the recess in the insulating layer 104 has a tapered shape, the lower portion of the light-shielding layer 109 also has a tapered shape.

[0286] The configuration in which the light-shielding layer has a tapered shape shown here can also be applied to other display devices.

[0287] [Specific Example 6] A modification of Fig. 3B is shown in Fig. 14A and Fig. 14B. As shown in Fig. 14A and Fig. 14B, the display device 100 is characterized by the use of a lens array 133. The lens array 133 can be provided overlapping the light-emitting device. By providing the lens array at a position overlapping the light-emitting device, the light emitted from the light-emitting device can be used efficiently. This makes it possible to realize a highly reliable display device.

[0288] 14A and 14B show an example in which a lens array 133 is provided on the light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B via a protective layer 131. By forming the lens array 133 directly on the substrate on which the light-emitting devices are formed, it is possible to improve the accuracy of alignment between the light-emitting devices and the lens array.

[0289] The display device 100 shown in FIG. 14A is an example in which a substrate 120 provided with a lens array 133 is bonded to a protective layer 131 by a resin layer 122. The protective layer 131 can be made of, for example, an inorganic material. The refractive index of the resin layer 122 is preferably smaller than the refractive index of the lens array 133. This can increase the light-emitting efficiency of the light-emitting device. By providing the lens array 133 on the substrate 120, the temperature of the heat treatment in the formation process can be increased.

[0290] The display device 100 shown in FIG. 14B includes a resin layer 122b and a protective layer 131 on the resin layer 122b. Because the top surface of the resin layer 122b is planarized, the top surface of the protective layer 131 is also planarized. The resin layer 122b and the protective layer 131 planarize the surface on which the lens array 133 is formed. This configuration is referred to as the protective layer 131 having a planarizing function. The refractive index of the resin layer 122b and the refractive index of the lens array 133 are preferably equal, and the refractive index of the resin layer 122b is preferably smaller than the refractive index of the lens array 133. This can increase the luminous efficiency of the light-emitting device. Meanwhile, the protective layer 131 shown in FIG. 14A can be referred to as having no planarizing function. However, it is also possible to flatten the top surface of the protective layer 131 by using an organic film for the protective layer 131, for example.

[0291] The convex surface of the lens array 133 may be configured to face the substrate 120. Alternatively, the convex surface of the lens array 133 may be configured to face the light-emitting device.

[0292] The lens array 133 can be formed using at least one of an inorganic material and an organic material. For example, a material containing a resin can be used for the lenses. Also, a material containing at least one of an oxide and a sulfide can be used for the lenses. For example, a microlens array can be used as the lens array 133. The lens array 133 can be formed directly on a substrate or a light-emitting device. Alternatively, a separately formed lens array can be attached to the light-emitting device.

[0293] The configuration of the lens array 133 shown here can also be applied to other display devices.

[0294] [Specific Example 7] A modified example of FIG. 3B is shown in FIGS. 15 to 16B. For a top view of the display device 100, see FIG. 1A. As shown in FIGS. 15 to 16B, the display device 100 is characterized by having colored layers. A colored layer 132R that transmits red light can be provided over the red light-emitting device 130R, a colored layer 132G that transmits green light can be provided over the green light-emitting device 130G, and a colored layer 132B that transmits blue light can be provided over the blue light-emitting device 130B. The colored layers 132R, 132G, and 132B may be collectively referred to as colored layers 132.

[0295] The colored layer 132R, which transmits red light, can block light of unnecessary wavelengths emitted from the red light-emitting device 130R. This configuration can further improve the color purity of the light emitted from each light-emitting device. Although the above description focuses on a red light-emitting device, the same effect can be achieved with the combination of the green light-emitting device 130G and the colored layer 132G, and the combination of the blue light-emitting device 130B and the colored layer 132B.

[0296] By providing a colored layer overlapping the light-emitting device, external light reflection can be significantly reduced, which is preferable. Furthermore, by having a light-emitting device with a microcavity structure, external light reflection can be further reduced. Thus, by applying either a colored layer or a microcavity structure, or preferably both, external light reflection can be sufficiently suppressed without using an optical component such as a circular polarizer in the display device. By not using a circular polarizer in the display device, attenuation of the light emitted from the light-emitting device can be suppressed, and the light extraction efficiency of the light-emitting device can be increased. This allows the power consumption of the display device to be reduced.

[0297] It is preferable that the colored layers of different colors have overlapping portions. The overlapping portions of the colored layers of different colors can function as light-blocking layers, thereby further reducing the reflection of external light.

[0298] 15 shows an example in which colored layers 132R, 132G, and 132B are provided on light-emitting devices 130R, 130G, and 130B via a protective layer 131. By forming the colored layers 132R, 132G, and 132B directly on the substrate on which the light-emitting devices are formed, the accuracy of alignment between the light-emitting devices and the colored layers can be improved. Furthermore, by positioning the light-emitting devices and the colored layers closer to each other, color mixing can be suppressed and viewing angle characteristics can be improved, which is preferable.

[0299] As shown in Figure 16A, the colored layer is preferably provided on a protective layer 131 having a planarizing function. By forming the colored layer on a highly flat surface, it is possible to prevent the colored layer from having irregularities depending on the surface on which it is formed. This prevents a portion of the light emitted from the light-emitting device from being diffused by the irregularities of the colored layer, thereby improving the display quality of the display device. For example, it is preferable that the protective layer 131 has an inorganic insulating film on the common electrode 115 and an organic insulating film on the inorganic insulating film.

[0300] 16B shows an example in which a substrate 120 provided with colored layers 132R, 132G, and 132B is attached to a protective layer 131 by a resin layer 122. By providing the colored layers 132R, 132G, and 132B on the substrate 120, the temperature of the heat treatment in the formation process of these layers can be increased.

[0301] Although not shown, the display device may be provided with both a colored layer and a lens array.

[0302] The colored layer configuration shown here can also be applied to other display devices.

[0303] [Specific Example 8] Fig. 17 shows a top view of a display device 100 different from that shown in Fig. 1A. A pixel 110 shown in Fig. 17 is composed of four types of subpixels: subpixel 11R, subpixel 11G, subpixel 11B, and subpixel 11S.

[0304] The subpixels 11R, 11G, 11B, and 11S may each have a light-emitting device that emits a different color light. For example, the subpixels 11R, 11G, 11B, and 11S may be subpixels of four colors R, G, B, and W, subpixels of four colors R, G, B, and B, subpixels of four colors R, G, B, and Y, or subpixels of R, G, B, and IR.

[0305] A display device according to an embodiment of the present invention can have a light receiving device in a pixel.

[0306] Of the four sub-pixels included in the pixel 110 shown in FIG. 17, three may have a light-emitting device and the remaining one may have a light-receiving device.

[0307] The light receiving device may be, for example, a pn-type or pin-type photodiode. The light receiving device functions as a photoelectric conversion device (also called a photoelectric conversion element) that detects light incident on the light receiving device and generates electric charges. The amount of electric charges generated by the light receiving device is determined based on the amount of light incident on the light receiving device.

[0308] The light-receiving device can detect either or both of visible light and infrared light. When detecting visible light, it can detect one or more of colors such as blue, purple, blue-purple, green, yellow-green, yellow, orange, and red. When detecting infrared light, it is preferable because it enables detection of an object even in a dark place.

[0309] In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light-receiving device. Organic photodiodes can be easily made thin, lightweight, and large in area, and have a high degree of freedom in shape and design, making them applicable to a variety of display devices.

[0310] In one embodiment of the present invention, an organic EL device is used as the light-emitting device, and an organic photodiode is used as the light-receiving device. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, the organic photodiode can be built into a display device using the organic EL device.

[0311] The light-receiving device is driven by applying a reverse bias between the pixel electrode and the common electrode, so that it can detect light incident on the light-receiving device, generate electric charges, and extract them as a current.

[0312] The same manufacturing method as for the light-emitting device can be applied to the light-receiving device. The island-shaped active layer (also called a photoelectric conversion layer) of the light-receiving device is not formed using a fine metal mask, but is formed by depositing a film that will become the active layer on the entire surface and processing the film. Therefore, the island-shaped active layer can be formed with a uniform thickness. Furthermore, by providing a mask layer on the active layer, damage to the active layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-receiving device.

[0313] The sixth embodiment can be referred to for the configuration and materials of the light receiving device.

[0314] 17 shows an example in which the aperture ratio (which can also be referred to as the size, the size of the light-emitting region, or the size of the light-receiving region) of subpixel 11S is larger than that of subpixels 11R, 11G, and 11B, but this embodiment of the present invention is not limited to this. The aperture ratios of subpixels 11R, 11G, 11B, and 11S can each be determined appropriately. The aperture ratios of subpixels 11R, 11G, 11B, and 11S can be configured to be different from each other, or any two or more of subpixels 11R, 11G, 11B, and 11S can be configured to be equal or approximately equal.

[0315] The subpixel 11S may have a higher aperture ratio than at least one of the subpixels 11R, 11G, and 11B. A larger light-receiving area of ​​the subpixel 11S may make it easier to detect an object. For example, depending on the resolution of the display device and the circuit configuration of the subpixels, the aperture ratio of the subpixel 11S may be higher than the aperture ratios of the other subpixels.

[0316] The subpixel 11S may have a lower aperture ratio than at least one of the subpixels 11R, 11G, and 11B. If the light-receiving area of ​​the subpixel 11S is small, the imaging range is narrowed, which makes it possible to suppress blurring in the imaging result and improve the resolution. This is preferable because it enables high-definition or high-resolution imaging.

[0317] In this way, the sub-pixel 11S can have a detection wavelength, resolution, and aperture ratio suited to the application.

[0318] The configuration of the sub-pixel 11S shown here can also be applied to other display devices.

[0319] In a display device according to one embodiment of the present invention, a light-shielding layer is provided between pixel electrodes, thereby preventing light from entering the transistor. This prevents light-induced changes in the electrical characteristics of the transistor. Therefore, a highly reliable transistor can be obtained, leading to a highly reliable display device. Furthermore, since light is prevented from entering a layer including a transistor, generation of stray light due to wiring or the like included in the layer can be suppressed. This allows a display device with high contrast. Furthermore, a display device with high visibility can be obtained.

[0320] This embodiment mode can be combined with other embodiment modes as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0321] Embodiment 2 In this embodiment, a manufacturing method of a display device according to one embodiment of the present invention will be described with reference to Figures 18A to 25. Note that with regard to materials and formation methods of elements, descriptions of parts similar to those described in Embodiment 1 may be omitted.

[0322] Here, an example of a method for manufacturing the display device shown in Fig. 3B will be described with reference to Fig. 18A to Fig. 25. Fig. 18A to Fig. 25 show a cross-sectional view taken along dashed dotted line X1-X2 and a cross-sectional view taken along dashed dotted line Y1-Y2 shown in Fig. 1A side by side.

[0323] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting display devices can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an atomic layer deposition (ALD) method, etc. CVD methods include a plasma enhanced chemical vapor deposition (PECVD) method and a thermal CVD method. One type of thermal CVD method is a metal organic chemical vapor deposition (MOCVD) method.

[0324] The thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by a wet film formation method such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0325] In particular, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet printing can be used to fabricate light-emitting devices. Vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, and chemical vapor deposition (CVD). In particular, functional layers included in the EL layer (hole injection layer, hole transport layer, hole blocking layer, light-emitting layer, electron blocking layer, electron transport layer, electron injection layer, charge generation layer, etc.) can be formed by vapor deposition (vacuum deposition, etc.), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), printing methods (inkjet printing, screen (stencil printing), offset (lithographic printing), flexography (relief printing), gravure, microcontact printing, etc.), etc.

[0326] When processing the thin film that constitutes the display device, a photolithography method or the like can be used. Alternatively, the thin film can be processed by a nanoimprint method, a sandblasting method, a lift-off method, or the like. Furthermore, an island-shaped thin film can be directly formed by a film formation method using a shielding mask such as a metal mask.

[0327] There are two typical photolithography methods: one is to form a resist mask on the thin film to be processed, process the thin film by etching or the like, and then remove the resist mask; the other is to form a photosensitive thin film, and then process the thin film into the desired shape by exposure and development.

[0328] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. Other examples include ultraviolet light, KrF laser light, and ArF laser light. Exposure can also be performed by immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays can also be used as the light used for exposure. An electron beam can also be used instead of the light used for exposure. Extreme ultraviolet light, X-rays, or an electron beam are preferred because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0329] For etching the thin film, dry etching, wet etching, sandblasting, or the like can be used.

[0330] First, a conductive film is formed on the substrate 103 and processed to form plugs 256R, 256G, and 256B ( FIG. 18A ). Note that a plug need not be provided in the connection portion 140. The conductive film can have a single-layer structure or a multilayer structure. A multilayer structure preferably includes a first titanium film, a first titanium nitride film on the first titanium film, an aluminum film on the first titanium nitride film, a second titanium film on the aluminum film, and a second titanium nitride film on the second titanium film. The thickness of the aluminum film is preferably thicker than the thicknesses of the first titanium film and the second titanium film. The thickness of the aluminum film is preferably thicker than the thicknesses of the first titanium nitride film and the second titanium nitride film. Increasing the thickness of the aluminum film can reduce the sheet resistance of the plug 256.

[0331] Subsequently, an insulating layer 104 is formed (FIG. 18B). As the insulating layer 104, a silicon oxide layer can be formed by a CVD method using an organic silane gas. The organic silane gas is tetraethyl ethoxysilane (TEOS: chemical formula Si(OC ２ H ５ ) ４ ), tetramethylsilane (TMS: chemical formula Si(CH ３ ) ４ ), tetramethylcyclotetrasiloxane (TMCTS), octamethylcyclotetrasiloxane (OMCTS), hexamethyldisilazane (HMDS), triethoxysilane (SiH(OC ２ H ５ ) ３ ), trisdimethylaminosilane (SiH(N(CH ３ ) ２ ) ３ Silicon-containing compounds such as tetrahydrofuran, ...

[0332] Next, a conductive film 111f that becomes the pixel electrode 111 is formed ( FIG. 18C ). The pixel electrode 111 preferably has a single-layer structure, or preferably has a stacked structure. In the case of a stacked structure, a stacked structure of a first titanium film, an aluminum film on the first titanium film, and a second titanium film on the aluminum film is preferably used. The thickness of the aluminum film is preferably thicker than the thicknesses of the first titanium film and the second titanium film. Increasing the thickness of the aluminum film can reduce the sheet resistance of the pixel electrode 111. Furthermore, after forming the second titanium film, heating is preferably performed at a temperature between 200°C and 400°C, preferably between 250°C and 320°C. Heating is preferably performed in an atmosphere containing oxygen and nitrogen, typically in the air. Because the surface and upper layer of the second titanium film are oxidized, a new titanium oxide film may be formed on the second titanium film. The thickness of the titanium oxide film is preferably 10 nm or less, more preferably 8 nm or less, and even more preferably 6 nm or less, so as not to impair the function as a pixel electrode. In addition, it is preferable to form a conductive film with high visible light reflectivity, such as an aluminum film, between the first titanium film and the second titanium film.

[0333] Furthermore, the pixel electrode 111 preferably has an oxide conductive film on the second titanium film. It is preferable to form an ITSO film as the oxide conductive film. If an ITSO film is formed on the second titanium film, the surface and upper layer of the second titanium film may be oxidized, and a new titanium oxide film may be formed on the second titanium film. It is preferable to set the thickness of the titanium oxide film to 10 nm or less, preferably 8 nm or less, and more preferably 6 nm or less, so as not to impair the function as a pixel electrode.

[0334] Subsequently, a resist mask 195R, a resist mask 195G, a resist mask 195B, and a resist mask 195p are formed over the conductive film 111f (FIG. 18D). The resist mask 195R, the resist mask 195G, the resist mask 195B, and the resist mask 195p are formed at positions overlapping with regions where the plugs 256R, the plugs 256G, the plugs 256B, and the connection portion 140 are to be provided.

[0335] The conductive film 111f is processed using the resist masks 195R, 195G, 195B, and 195p as masks to form the pixel electrodes 111R, 111G, and 111B, and the conductive layer 123 ( FIG. 19A ). The pixel electrodes 111R, 111G, and 111B may be collectively referred to as the pixel electrodes 111. The end of the pixel electrode 111 preferably has a tapered shape (with a taper angle of 60 degrees or more and less than 85 degrees). Furthermore, it is preferable that the end of the pixel electrode 111 be perpendicular or approximately perpendicular to the substrate 103 (with a taper angle of 85 degrees or more and 95 degrees or less), because this will also result in the side surfaces of the recess 112 in the process described below being perpendicular or approximately perpendicular. When the pixel electrode 111 has a stacked structure, the same processing method may be used for all the layers, or different processing methods may be used for each layer. The processing method may be selected from wet etching, dry etching, and other etching methods.

[0336] Next, a recess 112 is formed in the insulating layer 104 using resist masks 195R, 195G, 195B, and 195p ( FIG. 19B ). The processing method for forming the recess 112 is preferably the same as the processing method for the pixel electrode 111. When the pixel electrode 111 has a stacked structure, and when the underlying conductive film is processed by dry etching, it is preferable to process the recess 112 by dry etching as well. The depth of the recess can be determined taking into account the film thickness of the light-shielding layer 109. Alternatively, an opening may be formed in the insulating layer 104 instead of the recess. Next, the resist masks 195R, 195G, 195B, and 195p are removed.

[0337] Next, an organic material is applied to fill the recess 112, and the surface or surface layer of the organic material is removed to form the light-shielding layer 109 ( FIG. 19C ). Dry etching or chemical mechanical polishing (CMP) can be used to remove the organic material. Typically, dry etching is performed using etch-back with a controlled oxygen flow rate. The surface or surface layer of the organic material is preferably removed so that the top surface of the light-shielding layer 109 is lower than the top surface of the pixel electrode 111. Heat treatment is then preferably performed to release impurities such as gas from the light-shielding layer 109.

[0338] Next, an insulating film 139f is formed on the pixel electrode 111 and the light-shielding layer 109 ( FIG. 20A ). The insulating film 139f preferably contains an inorganic material. In this specification and the like, examples of inorganic materials include oxides, nitrides, oxynitrides, and nitride oxides. Examples of oxides include silicon oxide, aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, tantalum oxide, cerium oxide, gallium zinc oxide, and hafnium aluminate. Examples of nitrides include silicon nitride and aluminum nitride. Examples of oxynitrides include silicon oxynitride, aluminum oxynitride, gallium oxynitride, yttrium oxynitride, and hafnium oxynitride. Examples of nitride oxides include silicon nitride oxide and aluminum nitride oxide.

[0339] Next, a mask layer 196 is formed on the insulating film 139f (FIG. 20B). After that, the mask layer is used to process the insulating film 139f to form an insulating layer 139 (FIG. 20C). The insulating layer 139 can suppress diffusion of impurities from the light-shielding layer 109.

[0340] Next, film 113b is formed (FIG. 21A). Film 113b contains a compound containing a light-emitting material that emits blue light, and may also contain compounds that exhibit other functions. After processing, film 113b is called EL layer 113B. A connection section 140 may be added as a formation area of ​​film 113b. Furthermore, if film 113b is not formed in connection section 140, evaporation can be performed while covering connection section 140 with a mask layer. An area mask can be used as the mask layer.

[0341] In a display device according to one embodiment of the present invention, a material with high heat resistance is used for the light-emitting device. Specifically, the heat-resistant temperature of the compound contained in the film 113b is preferably 100° C. or higher and 180° C. or lower, more preferably 120° C. or higher and 180° C. or lower, and more preferably 140° C. or higher and 180° C. or lower. This can improve the reliability of the light-emitting device. Furthermore, the upper limit of the heating temperature during the manufacturing process of the display device can be increased. Therefore, the range of choices for materials and formation methods used for the display device can be expanded, and the manufacturing yield and reliability can be improved.

[0342] The film 113b can be formed by, for example, a vapor deposition method, specifically a vacuum deposition method, or by a transfer method, a printing method, an inkjet method, a coating method, or the like.

[0343] Next, a mask film 118b that will become the mask layer 118B is formed on the film 113b, and then a mask film 119b is formed on the mask film 118b (FIG. 21A). Note that in this embodiment, an example is shown in which the mask film is formed with a two-layer structure of the mask film 118b and the mask film 119b, but the mask film may have a single-layer structure or a laminated structure of three or more layers. The mask films 118b and 119b are also formed on the connection portion 140.

[0344] By providing the mask layer 118B over the film 113b, damage to the film 113b during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0345] The mask film 118b is made of a film that is highly resistant to the processing conditions of the film 113b, specifically, a film that has a high etching selectivity with respect to the film 113b.The mask film 119b is made of a film that has a high etching selectivity with respect to the mask film 118b.

[0346] The mask films 118b and 119b are formed at a temperature lower than the heat-resistant temperature of the film 113b. The substrate temperature when forming the mask films 118b and 119b is typically 200°C or lower, preferably 150°C or lower, more preferably 120°C or lower, more preferably 100°C or lower, and even more preferably 80°C or lower.

[0347] Examples of heat resistance temperature indicators include the glass transition point (Tg), softening point, melting point, thermal decomposition temperature, and 5% weight loss temperature. For example, the glass transition point (Tg) of the material contained in each layer constituting the EL layer can be used as an indicator of the heat resistance temperature. Furthermore, when the layer is a mixed layer made of multiple materials, for example, the glass transition point of the material contained in the largest amount can be used. Alternatively, the lowest temperature among the glass transition points of the multiple materials can be used.

[0348] In a display device according to one embodiment of the present invention, a material with high heat resistance is used for the light-emitting device. Therefore, the substrate temperature during the formation of the mask film can be set to 100° C. or higher, 120° C. or higher, or 140° C. or higher. The inorganic insulating film used for the mask film can be made denser and have a higher barrier property as the film formation temperature increases. Therefore, by forming the mask film at such a temperature, damage to the film 113b can be further reduced, and the reliability of the light-emitting device can be improved.

[0349] The mask films 118b and 119b can be formed by, for example, sputtering, ALD (including thermal ALD and PEALD), CVD, or vacuum deposition, or by the wet film formation method described above.

[0350] It is preferable that the mask film 118b formed on and in contact with the film 113b be formed using a formation method that causes less damage to the film 113b than the mask film 119b. For example, it is preferable to form the mask film 118b using the ALD method or the vacuum deposition method rather than the sputtering method.

[0351] It is preferable to use a film that can be removed by wet etching for each of the mask films 118b and 119b, since wet etching can reduce damage to the film 113b during processing of the mask films 118b and 119b compared to dry etching.

[0352] For each of the mask films 118b and 119b, for example, one or more of a metal film, an alloy film, a metal oxide film, a semiconductor film, an organic insulating film, an inorganic insulating film, and the like can be used.

[0353] The mask films 118b and 119b can each be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, or tantalum, or an alloy material containing such a metal material. It is particularly preferable to use a low-melting-point material such as aluminum or silver. Using a metal material capable of blocking ultraviolet rays for one or both of the mask films 118b and 119b is preferable because it can prevent ultraviolet rays from irradiating the film 113b and thereby prevent deterioration of the film 113b.

[0354] Using a metal film or an alloy film for one or both of the mask films 118b and 119b is preferable because plasma damage to the film 113b can be suppressed and deterioration of the film 113b can be suppressed. Specifically, plasma damage to the film 113b can be suppressed in processes using a dry etching method and ashing processes. In particular, using a metal film or an alloy film such as a tungsten film as the mask film 119b is preferable.

[0355] The mask film 118b and the mask film 119b can be made of a metal oxide such as In—Ga—Zn oxide, indium oxide, In—Zn oxide, In—Sn oxide, indium titanium oxide (In—Ti oxide), indium tin zinc oxide (In—Sn—Zn oxide), indium titanium zinc oxide (In—Ti—Zn oxide), indium gallium tin zinc oxide (In—Ga—Sn—Zn oxide), or indium tin oxide containing silicon.

[0356] In addition, instead of the above gallium, an element M (M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) can be used.

[0357] As the mask film, a film containing a material having light-shielding properties, particularly against ultraviolet light, can be used. For example, a film having reflectivity to ultraviolet light or a film absorbing ultraviolet light can be used. As the light-shielding material, various materials such as metals, insulators, semiconductors, and semimetals having light-shielding properties against ultraviolet light can be used. However, since part or all of the mask film will be removed in a later process, it is preferable that the mask film be a film that can be processed by etching, and particularly preferable that the processability is good.

[0358] For example, semiconductor materials such as silicon or germanium can be used as materials that are highly compatible with semiconductor manufacturing processes. Alternatively, oxides or nitrides of the above semiconductor materials can be used. Alternatively, non-metallic materials such as carbon or compounds thereof can be used. Alternatively, metals such as titanium, tantalum, tungsten, chromium, and aluminum, or alloys containing one or more of these, can be used. Alternatively, oxides containing the above metals, such as titanium oxide or chromium oxide, or nitrides such as titanium nitride, chromium nitride, or tantalum nitride can be used.

[0359] By using a film containing a material having ultraviolet light blocking properties as the mask film, it is possible to prevent the EL layer from being exposed to ultraviolet light during the exposure process, etc. By preventing the EL layer from being damaged by ultraviolet light, the reliability of the light-emitting device can be improved.

[0360] The same effect can be achieved when a film containing a material that blocks ultraviolet light is used as the material for the insulating film 125f described later.

[0361] The mask films 118b and 119b can each be made of an inorganic insulating film. In particular, an oxide insulating film is preferable because it has higher adhesion to the film 113b than a nitride insulating film. For example, the mask films 118b and 119b can each be made of an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide. For example, an aluminum oxide film can be formed as the mask films 118b and 119b by the ALD method. Using the ALD method is preferable because it can reduce damage to the underlying layer (particularly the EL layer).

[0362] For example, an inorganic insulating film (e.g., an aluminum oxide film) formed using the ALD method can be used as the mask film 118b, and an inorganic film (e.g., an In-Ga-Zn oxide film, a silicon film, or a tungsten film) formed using the sputtering method can be used as the mask film 119b.

[0363] The same inorganic insulating film can be used for both the mask film 118b and the insulating layer 125 to be formed later. For example, an aluminum oxide film formed using an ALD method can be used for both the mask film 118b and the insulating layer 125. The same deposition conditions can be applied to the mask film 118b and the insulating layer 125. Alternatively, different deposition conditions can be applied to the mask film 118b and the insulating layer 125. For example, by depositing the mask film 118b under the same conditions as the insulating layer 125, the mask film 118b can be an insulating layer with high barrier properties against at least one of water and oxygen. On the other hand, since the mask film 118b is a layer that is removed mostly or entirely in a later process, it is preferable that it be easily processed. Therefore, it is preferable that the mask film 118b be deposited under conditions where the substrate temperature during deposition is lower than that of the insulating layer 125.

[0364] An organic material can be used for one or both of the mask films 118b and 119b. For example, the organic material can be a material that is soluble in a solvent that is chemically stable with respect to at least the film located at the top of the film 113b. In particular, a material that dissolves in water or alcohol can be preferably used. When forming a film of such a material, it is preferable to apply the material dissolved in a solvent such as water or alcohol by a wet film formation method, and then perform a heat treatment to evaporate the solvent. In this case, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the film 113b.

[0365] The mask film 118b may be made of a material that is more water-soluble than the film 113b. For example, the mask film 118b may be made of a material that dissolves in an aqueous solution containing hydrogen fluoride (HF). Alternatively, the mask film 118b may be made of a material that dissolves in an aqueous solution containing tetramethylammonium hydroxide (TMAH).

[0366] Specifically, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq ３ ), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq ２), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), or other metal complexes can be used for the mask film 118b.

[0367] It is preferable that the mask film 118b is made of a water-soluble material and the mask film 119b is made of an inorganic film.

[0368] For example, the mask film 118b may be Alq ３ The mask film 119b may be an In-Ga-Zn oxide film, a silicon film, or a tungsten film.

[0369] By forming a water-soluble material as the mask film 118b on the EL layer 113B, even if the properties of the mask film 118b change during the manufacturing process, the light-emitting device 130B can be formed by removing the mask film 118b from the EL layer 113B. Furthermore, the mask film 118b exposed to plasma or the like during the manufacturing process can be removed. Furthermore, the mask film 118b can mitigate the effect of plasma or the like during the manufacturing process on the configuration located closer to the layer 101 than the mask film 118b. Furthermore, the EL layer 113B can be protected from damage during the manufacturing process. As a result, a novel display device with excellent convenience, usefulness, and reliability can be provided.

[0370] The mask membrane 118b and the mask membrane 119b can each be made of a resin such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, alcohol-soluble polyamide resin, or a fluororesin such as a perfluoropolymer.

[0371] For example, the mask film 118b can be an organic film (e.g., a PVA film) formed using either a vapor deposition method or the above-mentioned wet film formation method, and the mask film 119b can be an inorganic film (e.g., a silicon nitride film) formed using a sputtering method.

[0372] As described in the first embodiment, in the display device according to one embodiment of the present invention, a part of the mask film may remain as a mask layer.

[0373] Subsequently, a resist mask 190B is formed on the mask film 119b (FIG. 21B). The resist mask 190B can be formed by applying a photosensitive resin (photoresist) and then performing exposure and development.

[0374] The resist mask 190B can be made of a positive resist material or a negative resist material.

[0375] The resist mask 190B is provided at a position overlapping with the pixel electrode 111B. This can prevent damage to the conductive layer 123 during the manufacturing process of the display device. Note that no resist mask is provided on the connection portion 140.

[0376] Subsequently, a part of the mask film 119b is removed using the resist mask 190B to form a mask layer 119B (FIG. 21C). The mask layer 119B remains on the pixel electrode 111B.

[0377] Next, the resist mask 190B is removed. The resist mask 190B can be removed by, for example, ashing using oxygen plasma. Alternatively, the resist mask 190B can be removed by ashing using oxygen gas and CF ４ , C ４ F ８ , S.F. ６ , CHF ３ , Cl ２ , H ２ O, BCl ３, or a noble gas such as He. Alternatively, the resist mask 190B can be removed by wet etching. At this time, the mask film 118b is located on the outermost surface and the film 113b is not exposed, so that damage to the film 113b can be suppressed in the process of removing the resist mask 190B. Furthermore, the range of options for the method of removing the resist mask 190B can be expanded.

[0378] Subsequently, the mask film 118b and the film 113b are partially removed using the mask layer 119B as a mask, thereby forming the mask layer 118B and the EL layer 113B (FIG. 22A).

[0379] The mask films 118b and 119b can be processed by wet etching or dry etching, respectively, and are preferably processed by anisotropic etching.

[0380] By using the wet etching method, damage to the film 113b during processing of the mask films 118b and 119b can be reduced compared to when using the dry etching method. When using the wet etching method, it is preferable to use, for example, a developer, a tetramethylammonium hydroxide (abbreviated as TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed solution containing two or more of these. Note that the chemical solution used in the wet etching process may be alkaline or acidic.

[0381] In processing the mask film 119b, the film 113b is not exposed, and therefore the range of processing methods to be selected is wider than in processing the mask film 118b. Specifically, even when a gas containing oxygen is used as an etching gas in processing the mask film 119b, deterioration of the film 113b can be further suppressed.

[0382] When dry etching is used to process the mask film 118b, deterioration of the film 113b can be suppressed by not using a gas containing oxygen as the etching gas. ４ , C ４F ８ , SF ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ It is preferable to use a gas containing a noble gas such as He as the etching gas.

[0383] For example, when an aluminum oxide film formed by the ALD method is used as the mask film 118b, CHF ３ and He or CHF ３ and He and CH ４ The mask film 118b can be processed by dry etching using a diluted phosphoric acid. When an In-Ga-Zn oxide film formed by sputtering is used as the mask film 119b, the mask film 119b can be processed by wet etching using a diluted phosphoric acid. ４ The mask film 119b can be processed by dry etching using diluted phosphoric acid and Ar. Alternatively, the mask film 119b can be processed by wet etching using diluted phosphoric acid. When a tungsten film formed by sputtering is used as the mask film 119b, SF ６ , C.F. ４ and O ２ , or CF ４ and Cl ２ and O ２ The mask film 119b can be processed by dry etching using the above method.

[0384] As a result, a laminated structure of the EL layer 113B, the mask layer 118B, and the mask layer 119B remains on the pixel electrode 111B (FIG. 22A). Also, a part of the insulating layer 139 is exposed.

[0385] The insulating layer 139 functions as an etching stopper when the EL layer 113B is formed. For the insulating film 139f, it is preferable to use a material that is highly resistant to the formation of the EL layer 113B, specifically, a material that has a large etching selectivity with respect to the EL layer 113B. When processing the film 113b, the light-shielding layer 109 is covered with the insulating layer 139, and the surface of the light-shielding layer 109 is not exposed to etching gas or etching solution, etc. This makes it possible to prevent the thickness of the light-shielding layer 109 from becoming thin.

[0386] The film 113b is preferably processed by anisotropic etching, particularly anisotropic dry etching, or alternatively, wet etching.

[0387] When the film 113b is processed by dry etching, the surface of the display device being manufactured is exposed to plasma. Using a metal film or an alloy film for one or both of the mask layers 118B and 119B is preferable because it can prevent damage caused by plasma to the remaining portion of the film 113b (the portion that will become the EL layer 113B) and therefore prevent deterioration of the EL layer 113B. In particular, it is preferable to use a metal film or an alloy film for the mask layer 119B, and a tungsten film or a molybdenum film can be suitably used.

[0388] When dry etching is used to process the film 113b, deterioration of the film 113b can be suppressed by not using a gas containing oxygen as an etching gas.

[0389] A gas containing oxygen can also be used as the etching gas. When the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching rate. This can suppress damage to the film 113b. Furthermore, problems such as adhesion of reaction products that occur during etching can be suppressed.

[0390] When dry etching is used, for example, H ２ , C.F. ４ , C ４ F ８ , S.F. ６, CHF ３ , Cl ２ , H ２ O, BCl ３ It is preferable to use a gas containing one or more of the noble gases such as He and Ar as the etching gas. Alternatively, it is preferable to use a gas containing one or more of these and oxygen as the etching gas. Alternatively, oxygen gas can be used as the etching gas. Specifically, for example, H ２ and a gas containing Ar, or CF ４ A gas containing CF and He can be used as an etching gas. ４ A gas containing H, He, and oxygen can be used as the etching gas. ２ A gas containing Ar and a gas containing oxygen can be used as the etching gas.

[0391] The dry etching apparatus may be a dry etching apparatus having a high-density plasma source. Examples of the dry etching apparatus having a high-density plasma source include an inductively coupled plasma (ICP) etching apparatus. Alternatively, a capacitively coupled plasma (CCP) etching apparatus having parallel-plate electrodes may be used. The capacitively coupled plasma etching apparatus having parallel-plate electrodes may be configured to apply a high-frequency voltage to one of the parallel-plate electrodes. Alternatively, it may be configured to apply a plurality of different high-frequency voltages to one of the parallel-plate electrodes. Alternatively, it may be configured to apply a high-frequency voltage of the same frequency to each of the parallel-plate electrodes. Alternatively, it may be configured to apply high-frequency voltages of different frequencies to each of the parallel-plate electrodes.

[0392] Because the insulating layer 139 covers the edges of the pixel electrodes 111R, 111G, and 111B, corrosion may occur during an etching process or the like for these edges. The products resulting from corrosion of the pixel electrodes 111R, 111G, and 111B may be unstable. For example, in wet etching, they may dissolve in the solution, and in dry etching, they may scatter into the atmosphere. When the products dissolve in the solution or scatter into the atmosphere, they may adhere to the processed surface and the side surfaces of the EL layer 113B, for example, which may adversely affect the characteristics of the light-emitting devices or form leak paths between multiple light-emitting devices. Furthermore, in areas where the edges of the pixel electrode 111B are exposed, the adhesion between adjacent layers may be reduced, potentially making the EL layer 113B or the pixel electrode 111B more susceptible to peeling. Therefore, by configuring the insulating layer 139 to cover the pixel electrodes 111R, 111G, and 111B, it is possible to improve, for example, the yield and characteristics of the light-emitting device.

[0393] At the connection portion 140 and its vicinity, the laminated structure of the mask layer 118B and the mask layer 119B remains on the conductive layer 123.

[0394] 20C to 22A, a stacked structure of the EL layer 113G, the mask layer 118G, and the mask layer 119G remains on the pixel electrode 111G. Also, a part of the insulating layer 139 is exposed (FIG. 22B). At the connection portion 140, the conductive layer 123 is exposed.

[0395] 20C to 22A, a stacked structure of the EL layer 113R, the mask layer 118R, and the mask layer 119R remains on the pixel electrode 111R. Also, a part of the insulating layer 139 is exposed (FIG. 22C). At the connection portion 140, the conductive layer 123 is exposed.

[0396] Note that the side surfaces of the EL layers 113B, 113G, and 113R are preferably perpendicular or approximately perpendicular to the surface where they are formed (here, a part of the top surface of the insulating layer 139). For example, the angle between the surface where they are formed and these side surfaces is preferably 60 degrees or more and 90 degrees or less. Furthermore, it is preferable that adjacent layers among the EL layers 113B, 113G, and 113R have side surfaces facing each other.

[0397] As described above, the distance between any two adjacent ones of the EL layers 113B, 113G, and 113R formed using photolithography can be narrowed to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Here, the distance can be defined, for example, as the distance between the opposing ends of any two adjacent ones of the EL layers 113B, 113G, and 113R. By narrowing the distance between the island-shaped EL layers in this way, a display device with high definition and a large aperture ratio can be provided.

[0398] Next, the mask layers 119B, 119G, and 119R are removed ( FIG. 23A ). For example, when the mask layers 119B, 119G, and 119R are made of a conductive material, removing the mask layers 119B, 119G, and 119R can suppress the generation of leakage current and the formation of capacitance due to the remaining mask layers 119B, 119G, and 119R.

[0399] Here, a manufacturing method in which the mask layers 119B, 119G, and 119R are removed will be described as an example, but a configuration in which parts of the mask layers 119B, 119G, and 119R are left may also be used. For example, if the mask layers 119B, 119G, and 119R contain a material that has the above-mentioned ultraviolet light blocking properties, proceeding to the next step without removing them is preferable because the island-shaped EL layer can be protected from ultraviolet light.

[0400] The mask layers 119B, 119G, and 119R can be removed using the same method as that used to form the mask layers 119B, 119G, and 119R. In particular, by using the wet etching method, damage to the EL layers 113B, 113G, and 113R can be reduced compared to when using the dry etching method when removing the mask layers 119B, 119G, and 119R.

[0401] When a metal film or an alloy film is used for the mask layers 119B, 119G, and 119R, the presence of the mask layers 119B, 119G, and 119R can prevent plasma damage to the EL layer. Therefore, the film can be processed using a dry etching method in the steps up to the removal of the mask layers 119B, 119G, and 119R. On the other hand, in the steps of removing the mask layers 119B, 119G, and 119R and in the steps thereafter, the film that prevents plasma damage to the EL layer is lost, so it is preferable to process the film using a method that does not use plasma, such as a wet etching method.

[0402] The mask layers 119B, 119G, and 119R can be removed by dissolving them in a solvent such as water or alcohol. Examples of alcohol include ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), and glycerin.

[0403] Next, an insulating film 125f that will become the insulating layer 125 is formed so as to cover the insulating layer 139, the light-shielding layer 109, the EL layer 113B, the EL layer 113G, the EL layer 113R, the mask layer 118B, the mask layer 118G, and the mask layer 118R (FIG. 23B).

[0404] Thereafter, an insulating film 127f, which will become the insulating layer 127, is formed in contact with the upper surface of the insulating film 125f. Therefore, it is preferable that the upper surface of the insulating film 125f has high adhesion to the resin composition (e.g., a photosensitive resin composition containing an acrylic resin) used for the insulating film 127f. To improve this adhesion, it is preferable to hydrophobize (or increase the hydrophobicity of) the upper surface of the insulating film 125f by performing a surface treatment. For example, it is preferable to perform the treatment using a silylating agent such as hexamethyldisilazane (HMDS). By hydrophobizing the upper surface of the insulating film 125f in this manner, the insulating film 127f can be formed with high adhesion.

[0405] Subsequently, an insulating film 127f is formed on the insulating film 125f (FIG. 23B).

[0406] The insulating films 125f and 127f are preferably formed by a formation method that causes less damage to the EL layer 113B, the EL layer 113G, and the EL layer 113R. In particular, since the insulating film 125f is formed in contact with the side surfaces of the EL layer 113B, the EL layer 113G, and the EL layer 113R, it is preferably formed by a formation method that causes less damage to the EL layer 113B, the EL layer 113G, and the EL layer 113R than the insulating film 127f.

[0407] The insulating films 125f and 127f are formed at a temperature lower than the heat resistance temperatures of the EL layers 113B, 113G, and 113R, respectively. By increasing the substrate temperature during film formation, the insulating film 125f can have a low impurity concentration and a high barrier property against at least one of water and oxygen, even if it is thin.

[0408] The substrate temperature when forming the insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher, and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower, respectively.

[0409] As described above, in a display device according to one embodiment of the present invention, a material with high heat resistance is used for the light-emitting device. Therefore, the substrate temperature during the formation of the insulating film 125f and the insulating film 127f can be set to 100°C or higher, 120°C or higher, or 140°C or higher, respectively. For example, the higher the deposition temperature of an inorganic insulating film, the denser the film can be and the higher the barrier properties can be. Therefore, by depositing the insulating film 125f at such a temperature, damage to the EL layer 113B, the EL layer 113G, and the EL layer 113R can be further reduced, thereby improving the reliability of the light-emitting device.

[0410] The insulating film 125f is preferably formed to a thickness of 3 nm or more, 5 nm or more, or 10 nm or more, and 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less, within the above substrate temperature range.

[0411] The insulating film 125f is preferably formed by, for example, an ALD method. The ALD method is preferable because it can reduce film formation damage and form a film with high coverage. For example, an aluminum oxide film is preferably formed as the insulating film 125f by the ALD method.

[0412] The insulating film 125f can also be formed by a sputtering method, a CVD method, or a PECVD method, which have a faster film formation rate than an ALD method, thereby enabling a highly reliable display device to be manufactured with high productivity.

[0413] The insulating film 127f is preferably formed by the wet film formation method described above. The insulating film 127f is preferably formed by, for example, spin coating using a photosensitive resin, more specifically, using a photosensitive resin composition containing an acrylic resin.

[0414] Heat treatment (also referred to as pre-baking) is preferably performed after the insulating film 127f is formed. The temperature of the heat treatment is set to be lower than the upper temperature limit of the EL layers 113B, 113G, and 113R. The substrate temperature during the heat treatment is preferably 50° C. or higher and 200° C. or lower, more preferably 60° C. or higher and 150° C. or lower, and further preferably 70° C. or higher and 120° C. or lower. This allows the solvent contained in the insulating film 127f to be removed.

[0415] Next, visible light or ultraviolet light is irradiated onto a portion of the insulating film 127f to expose that portion. For example, when a positive photosensitive resin composition containing an acrylic resin is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto an area where the insulating layer 127 will not be formed in a later step. Note that the width of the insulating layer 127 can be controlled by the area to be exposed to light.

[0416] The light used for exposure preferably contains i-line (wavelength 365 nm), and may contain at least one of g-line (wavelength 436 nm) and h-line (wavelength 405 nm).

[0417] Subsequently, development is performed to form an insulating layer 127 ( FIG. 23C ). The insulating layer 127 is formed in the region surrounding the EL layer 113R, the region surrounding the EL layer 113G, and the region surrounding the EL layer 113B. When an acrylic resin is used for the insulating film 127f, it is preferable to use an alkaline solution as the developer, such as an aqueous solution of tetramethylammonium hydroxide (abbreviated as TMAH).

[0418] After development, a step of removing residues (so-called scum) remaining after development can be carried out. For example, the residues can be removed by ashing using oxygen plasma. After each of the development steps described below, a step of removing the residues can also be carried out.

[0419] Etching can also be performed to adjust the height of the surface of the insulating layer 127. The insulating layer 127 can be processed by ashing using oxygen plasma, for example.

[0420] After development, heat treatment (also referred to as post-baking) is preferably performed. Heat treatment can form tapered side surfaces of the insulating layer 127. The heat treatment is performed at a temperature lower than the heat resistance temperature of the EL layer. The heat treatment can be performed at a substrate temperature of 50° C. to 200° C., preferably 60° C. to 150° C., and more preferably 70° C. to 130° C. The heating atmosphere can be, for example, an air atmosphere or an inert gas atmosphere. The heating atmosphere can be an atmospheric pressure atmosphere or a reduced-pressure atmosphere. A reduced-pressure atmosphere is preferable because drying can be performed at a lower temperature. The substrate temperature in this heat treatment step is preferably higher than that in the heat treatment (pre-baking) performed after the formation of the insulating film 127f. This can improve adhesion between the insulating layer 127 and the insulating layer 125 and also improve the corrosion resistance of the insulating layer 127.

[0421] Next, using the insulating layer 127 as a mask, the insulating film 125f, and portions of the mask layer 118B, the mask layer 118G, and the mask layer 118R are removed, thereby forming the insulating layer 125, and openings are formed in the mask layer 118B, the mask layer 118G, and the mask layer 118R, respectively, exposing the upper surfaces of the EL layers 113G, 113G, and 113R ( FIG. 24A ).

[0422] The insulating film 125f, the mask layer 118B, the mask layer 118G, and the mask layer 118R can be processed by dry etching or wet etching. Note that it is preferable to use the same material as the mask layer 118B, the mask layer 118G, and the mask layer 118R for the insulating film 125f because the processing can be performed all at once.

[0423] When dry etching is used, it is preferable to use a chlorine-based gas. ２ , BCl ３ , SiCl ４ , and CCl ４The above-mentioned chlorine-based gases may be used alone or in combination of two or more thereof. Furthermore, the above-mentioned chlorine-based gases may be used alone or in combination of two or more thereof. By using dry etching, thin regions of the mask layers 118B, 118G, and 118R can be formed with good in-plane uniformity.

[0424] When dry etching is used, by-products generated by the dry etching may be deposited on the upper surface and side surfaces of the insulating layer 127. Therefore, the insulating layer 127 may contain components contained in the etching gas, components contained in the insulating film 125f, and components contained in the mask layers 118B, 118G, and 118R.

[0425] It is preferable to use a wet etching method for processing the insulating film 125f, the mask layer 118B, the mask layer 118G, and the mask layer 118R. By using the wet etching method, damage to the EL layer 113B, the EL layer 113G, and the EL layer 113R can be reduced compared to when using a dry etching method. For example, an alkaline solution can be used as an etchant for the wet etching. For example, an aqueous solution of tetramethylammonium hydroxide (abbreviated as TMAH), which is an alkaline solution, can be suitably used for wet etching of an aluminum oxide film.

[0426] As described above, by providing the insulating layer 127, the insulating layer 125, the mask layer 118B, the mask layer 118G, and the mask layer 118R, it is possible to prevent connection failures caused by disconnected portions and increases in electrical resistance caused by locally thin portions in the common layer 114 and the common electrode 115 between the light-emitting devices. As a result, the display device according to one embodiment of the present invention can improve the display quality.

[0427] After exposing portions of the EL layer 113B, the EL layer 113G, and the EL layer 113R, further heat treatment can be performed. This heat treatment can remove water contained in the EL layer and water adsorbed to the surface of the EL layer. Furthermore, this heat treatment may change the shape of the insulating layer 127. Specifically, the insulating layer 127 may expand to cover at least one of the ends of the insulating layer 125, the ends of the mask layers 118B, 118G, and 118R, and the top surfaces of the EL layer 113B, the EL layer 113G, and the EL layer 113R. For example, heat treatment can be performed in an inert gas atmosphere or a reduced-pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50° C. to 200° C., preferably 60° C. to 150° C., and more preferably 70° C. to 120° C. A reduced-pressure atmosphere is preferable because dehydration can be achieved at lower temperatures. However, the temperature range of the heat treatment is preferably set appropriately, taking into account the heat resistance temperature of the EL layer. In addition, when the heat resistance temperature of the EL layer is taken into consideration, a temperature of 70° C. or more and 120° C. or less is particularly suitable within the above temperature range.

[0428] Here, if the insulating layer 125 and the mask layer are etched together after post-baking, side etching may cause the insulating layer 125 and the mask layer below the edge of the insulating layer 127 to disappear, forming a cavity. Such a cavity may cause unevenness on the surface on which the common layer 114 and the common electrode 115 are formed, making it more likely that discontinuities will occur in the common layer 114 and the common electrode 115. Therefore, it is preferable to perform the etching of the insulating layer 125 and the mask layer separately, before and after post-baking.

[0429] Next, the common layer 114 and the common electrode 115 are formed in this order on the insulating layer 127, the EL layer 113B, the EL layer 113G, and the EL layer 113R, and further a protective layer 131 is formed (FIG. 24B).

[0430] The common layer 114 can be formed by, for example, a vapor deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, or a coating method.

[0431] The common electrode 115 can be formed by, for example, sputtering or vacuum deposition, or by stacking a film formed by deposition and a film formed by sputtering.

[0432] The protective layer 131 can be formed by, for example, vacuum deposition, sputtering, CVD, or ALD.

[0433] Subsequently, the substrate 120 is attached onto the protective layer 131 using the resin layer 122, whereby a display device can be manufactured (FIG. 25).

[0434] As described above, in the manufacturing method of the display device of this embodiment, the island-shaped EL layers 113B, 113G, and 113R are formed by depositing and processing a film over the entire surface rather than using a fine metal mask. This allows the island-shaped layers to be formed with a uniform thickness. This allows a high-resolution display device or a display device with a high aperture ratio to be realized. Furthermore, even if the resolution or aperture ratio is high and the distance between subpixels is extremely short, the EL layers 113B, 113G, and 113R can be prevented from contacting each other in adjacent subpixels. Therefore, leakage current between subpixels can be suppressed. This prevents unintended light emission due to crosstalk, thereby realizing a display device with extremely high contrast.

[0435] Although an example in which the EL layer 113B, the EL layer 113G, and the EL layer 113R are formed in this order has been described, the order in which these layers are formed is not particularly limited.

[0436] By providing the insulating layer 127 having a tapered edge between adjacent island-shaped EL layers, it is possible to suppress the occurrence of a step during the formation of the common electrode 115 and also to prevent the formation of a locally thin portion in the common electrode 115. This makes it possible to suppress the occurrence of a connection failure due to the disconnected portion in the common layer 114 and the common electrode 115 and an increase in electrical resistance due to the locally thin portion. Therefore, a display device according to one embodiment of the present invention can achieve both high definition and high display quality.

[0437] This embodiment mode can be combined with other embodiment modes as appropriate.

[0438] Embodiment 3 [Pixel Circuit] In this embodiment, a structural example of a pixel circuit that can be used for a subpixel included in a display device according to one embodiment of the present invention will be described with reference to FIGS.

[0439] 26, the subpixel 11A includes a pixel circuit 12A and a light-emitting device 130A. The pixel circuit 12A includes a transistor M51, a transistor M52, a transistor M53, and a capacitor C51. The transistor M52 can correspond to the transistor 253 described in the above embodiment.

[0440] The gate of the transistor M52 is connected to one of the source or drain of the transistor M51 and one terminal of the capacitor C51 via a wiring NL52. The one of the source or drain of the transistor M52 is electrically connected to the other terminal of the capacitor C51, one of the source or drain of the transistor M53, and one terminal (e.g., the anode terminal) of the light-emitting device 130A via a wiring NL51.

[0441] The other of the source and the drain of the transistor M52 is electrically connected to the wiring ANO. The other terminal (e.g., the cathode terminal) of the light-emitting device 130A is electrically connected to the wiring CATHO. The other of the source and the drain of the transistor M51 is electrically connected to the wiring DL. The other of the source and the drain of the transistor M53 is electrically connected to the wiring VL0. The gates of the transistors M51 and M53 are electrically connected to the wiring GLa.

[0442] The light emitting device 130A emits light with an intensity that corresponds to the amount of current flowing through the light emitting device 130A. For example, an organic EL element can be used as the light emitting device 130A.

[0443] The transistor M52 can change its drain current depending on the potential applied to its gate. Therefore, in the pixel circuit 12A, the transistor M52 has the function of controlling the amount of current flowing through the light-emitting device 130A. In other words, the transistor M52 has the function of controlling the light emission intensity of the light-emitting device 130A. In this specification and the like, a transistor having a function similar to that of the transistor M52 may be referred to as a "drive transistor."

[0444] The transistor M51 has a function of turning on or off the gate of the transistor M52 and the wiring DL (functioning as a switch). The transistor M53 has a function of turning on or off the source or drain of the transistor M52 and the wiring VL0 (functioning as a switch). The capacitor C51 has a function of holding a potential difference (voltage) between the gate of the transistor M52 and the source or drain of the transistor M52 when the wiring NL52 is floating, for example.

[0445] The wiring GLa may be referred to as, for example, a gate line, a scan line, or a selection line, etc. The wiring DL may be referred to as, for example, a source line, a data line, or a signal line, etc.

[0446] In the subpixel 11A, the current flowing through the transistor M52 or the current flowing through the light-emitting device 130A can be output to the line VL0 via the transistor M53. Therefore, the line VL0 may be referred to as a monitor line.

[0447] In one embodiment of the present invention, various transistors can be used as transistors (transistors M51 to M53) included in the pixel circuit 12A. For example, n-channel transistors can be used for some or all of the transistors included in the pixel circuit 12A. Alternatively, for example, p-channel transistors can be used.

[0448] Furthermore, for example, transistors having a back gate can be used for some or all of the transistors that configure the pixel circuit 12A.

[0449] This embodiment mode can be combined with other embodiment modes as appropriate.

[0450] Embodiment 4 In this embodiment, a display device according to one embodiment of the present invention will be described with reference to FIGS. 27 and 28. FIG.

[0451] [Pixel Layout] In this embodiment, pixel layouts different from that shown in FIG. 1A will be mainly described. There are no particular limitations on the arrangement of sub-pixels, and various methods can be applied. Examples of sub-pixel arrangements include a stripe arrangement, an S-stripe arrangement, a matrix arrangement, a delta arrangement, a Bayer arrangement, and a pentile arrangement.

[0452] The top surface shape of the sub-pixels shown in the drawings in this embodiment corresponds to the top surface shape of the light-emitting region (or light-receiving region).

[0453] The top surface shape of the subpixel may be, for example, a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, or a circle.

[0454] The layout of the circuits constituting the sub-pixels is not limited to the range of the sub-pixels shown in the figure, and can also be arranged outside of the sub-pixels.

[0455] An S-stripe arrangement is applied to the pixel 110 shown in Fig. 27A. The pixel 110 shown in Fig. 27A is composed of three subpixels: a subpixel 110a, a subpixel 110b, and a subpixel 110c.

[0456] 27B includes a subpixel 110a having a generally trapezoidal or triangular top surface shape with rounded corners, a subpixel 110b having a generally triangular or triangular top surface shape with rounded corners, and a subpixel 110c having a generally rectangular or hexagonal top surface shape with rounded corners. Furthermore, the subpixel 110b has a larger light-emitting region than the subpixel 110a. In this manner, the shape and size of each subpixel can be determined independently. For example, the more reliable the light-emitting device, the smaller the size of the subpixel.

[0457] The Pentile arrangement is applied to the pixels 124a and 124b shown in Fig. 27C. Fig. 27C shows an example in which the pixel 124a having the subpixels 110a and 110b and the pixel 124b having the subpixels 110b and 110c are arranged alternately.

[0458] 27D to 27F are arranged in a delta configuration. Pixel 124a has two subpixels (subpixel 110a and subpixel 110b) in the top row (first row) and one subpixel (subpixel 110c) in the bottom row (second row). Pixel 124b has one subpixel (subpixel 110c) in the top row (first row) and two subpixels (subpixel 110a and subpixel 110b) in the bottom row (second row).

[0459] Figure 27D is an example in which each subpixel has an approximately rectangular top surface shape with rounded corners, Figure 27E is an example in which each subpixel has a circular top surface shape, and Figure 27F is an example in which each subpixel has an approximately hexagonal top surface shape with rounded corners.

[0460] In Figure 27F, each subpixel is arranged inside a densely arranged hexagonal region. When focusing on one subpixel, it is arranged so that it is surrounded by six other subpixels. Furthermore, subpixels that emit light of the same color are arranged so that they are not adjacent to each other. For example, when focusing on subpixel 110a, three subpixels 110b and three subpixels 110c are arranged alternately so as to surround it.

[0461] 27G shows an example in which subpixels of each color are arranged in a zigzag pattern. Specifically, in the top view, the positions of the upper sides of two subpixels aligned in the row direction (for example, subpixels 110a and 110b, or subpixels 110b and 110c) are misaligned.

[0462] 27A to 27G, it is preferable that the subpixel 110a be the subpixel R that emits red light, the subpixel 110b be the subpixel G that emits green light, and the subpixel 110c be the subpixel B that emits blue light. Note that the configuration of the subpixels is not limited to this, and the colors that the subpixels emit and their order of arrangement can be determined appropriately. For example, the subpixel 110b can be the subpixel R that emits red light, and the subpixel 110a can be the subpixel G that emits green light.

[0463] In photolithography, the finer the pattern to be processed, the more significant the effect of light diffraction becomes. This reduces the fidelity of the photomask pattern when it is transferred by exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, it is likely to have rounded corners. As a result, the top surface shape of the subpixel may become a polygon with rounded corners, an ellipse, a circle, or the like.

[0464] Furthermore, in a method for manufacturing a display device according to one embodiment of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the EL layer material and the curing temperature of the resist material, the resist film may not be cured sufficiently. A resist film that is not cured sufficiently may take a shape that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer may become a polygon with rounded corners, an ellipse, a circle, or the like. For example, when attempting to form a resist mask with a square top surface shape, a resist mask with a circular top surface shape may be formed, resulting in a circular top surface shape of the EL layer.

[0465] In order to form the top surface of the EL layer into a desired shape, a technique for correcting the mask pattern in advance (OPC (Optical Proximity Correction) technique) can be used so that the design pattern and the transfer pattern coincide with each other. Specifically, the OPC technique adds a correction pattern to the corners of figures on the mask pattern.

[0466] As shown in Figures 28A to 28I, a pixel can be configured to have four types of sub-pixels.

[0467] The pixels 110 shown in FIGS. 28A to 28C are arranged in a stripe pattern.

[0468] Figure 28A is an example in which each subpixel has a rectangular top surface shape, Figure 28B is an example in which each subpixel has a top surface shape that is a combination of two semicircles and a rectangle, and Figure 28C is an example in which each subpixel has an elliptical top surface shape.

[0469] The pixels 110 shown in FIGS. 28D to 28F are arranged in a matrix.

[0470] Figure 28D is an example in which each sub-pixel has a square top surface shape, Figure 28E is an example in which each sub-pixel has an approximately square top surface shape with rounded corners, and Figure 28F is an example in which each sub-pixel has a circular top surface shape.

[0471] 28G and 28H show an example in which one pixel 110 is configured in two rows and three columns.

[0472] 28G has three subpixels (subpixels 110a, 110b, and 110c) in the top row (first row) and one subpixel (subpixel 110d) in the bottom row (second row). In other words, pixel 110 has subpixel 110a in the left column (first column), subpixel 110b in the center column (second column), subpixel 110c in the right column (third column), and subpixel 110d across these three columns.

[0473] The pixel 110 shown in FIG. 28H has three subpixels (subpixels 110a, 110b, and 110c) in the top row (first row) and three subpixels 110d in the bottom row (second row). In other words, the pixel 110 has subpixels 110a and 110d in the left column (first column), subpixels 110b and 110d in the center column (second column), and subpixels 110c and 110d in the right column (third column). By aligning the subpixels in the top and bottom rows as shown in FIG. 28H, it is possible to efficiently remove dust and other particles that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided.

[0474] FIG. 28I shows an example in which one pixel 110 is configured in three rows and two columns.

[0475] 28I has subpixel 110a in the top row (first row), subpixel 110b in the middle row (second row), subpixel 110c across the first and second rows, and one subpixel (subpixel 110d) in the bottom row (third row). In other words, pixel 110 has subpixels 110a and 110b in the left column (first column), subpixel 110c in the right column (second column), and subpixel 110d across these two columns.

[0476] The pixel 110 shown in FIGS. 28A to 28I is composed of four subpixels: a subpixel 110a, a subpixel 110b, a subpixel 110c, and a subpixel 110d.

[0477] The subpixels 110a, 110b, 110c, and 110d may each have a light-emitting device that emits a different color light, such as subpixels of four colors R, G, B, and white (W), subpixels of four colors R, G, B, and Y, or subpixels of R, G, B, and infrared (IR).

[0478] 28A to 28I , it is preferable that, for example, the subpixel 110a be the subpixel R that emits red light, the subpixel 110b be the subpixel G that emits green light, the subpixel 110c be the subpixel B that emits blue light, and the subpixel 110d be any one of the subpixels W that emit white light, Y that emit yellow light, and IR that emit near-infrared light. With such a configuration, the pixel 110 shown in FIGS. 28G and 28H has a stripe layout of R, G, and B, thereby improving display quality. Furthermore, the pixel 110 shown in FIG. 28I has a so-called S-stripe layout of R, G, and B, thereby improving display quality.

[0479] The pixel 110 can have sub-pixels that have light receiving devices.

[0480] In each pixel 110 shown in FIGS. 28A to 28I, any one of the subpixels 110a to 110d can be a subpixel having a light-receiving device.

[0481] 28A to 28I , it is preferable that, for example, the subpixel 110a be the subpixel R that emits red light, the subpixel 110b be the subpixel G that emits green light, the subpixel 110c be the subpixel B that emits blue light, and the subpixel 110d be the subpixel S that has a light-receiving device. With this configuration, the pixels 110 shown in FIGS. 28G and 28H have a stripe layout of R, G, and B, which can improve display quality. Furthermore, the pixel 110 shown in FIG. 28I has a so-called S-stripe layout of R, G, and B, which can improve display quality.

[0482] The wavelength of light detected by the subpixel S having the light receiving device is not particularly limited. The subpixel S can be configured to detect either or both of visible light and infrared light.

[0483] As shown in Figures 28J and 28K, a pixel can be configured to have five types of sub-pixels.

[0484] FIG. 28J shows an example in which one pixel 110 is configured in two rows and three columns.

[0485] 28J has three subpixels (subpixels 110a, 110b, and 110c) in the top row (first row) and two subpixels (subpixels 110d and 110e) in the bottom row (second row). In other words, pixel 110 has subpixels 110a and 110d in the left column (first column), subpixel 110b in the center column (second column), subpixel 110c in the right column (third column), and subpixel 110e from the second column to the third column.

[0486] FIG. 28K shows an example in which one pixel 110 is configured in three rows and two columns.

[0487] 28K has subpixel 110a in the top row (first row), subpixel 110b in the middle row (second row), subpixel 110c across the first and second rows, and two subpixels (subpixels 110d and 110e) in the bottom row (third row). In other words, pixel 110 has subpixels 110a, 110b, and 110d in the left column (first column), and subpixels 110c and 110e in the right column (second column).

[0488] 28J and 28K, it is preferable that the subpixel 110a be the subpixel R that emits red light, the subpixel 110b be the subpixel G that emits green light, and the subpixel 110c be the subpixel B that emits blue light. With this configuration, the pixel 110 shown in FIG. 28J has a stripe layout of R, G, and B, which can improve display quality. Furthermore, the pixel 110 shown in FIG. 28K has a so-called S-stripe layout of R, G, and B, which can improve display quality.

[0489] 28J and 28K, it is preferable to use a subpixel S having a light-receiving device in at least one of the subpixels 110d and 110e. When a light-receiving device is used in both the subpixels 110d and 110e, the configurations of the light-receiving devices may be different from each other. For example, the wavelength ranges of light detected may be at least partially different from each other. Specifically, one of the subpixels 110d and 110e may have a light-receiving device that mainly detects visible light, and the other may have a light-receiving device that mainly detects infrared light.

[0490] 28J and 28K, it is preferable that one of the subpixels 110d and 110e is a subpixel S having a light-receiving device, and the other is a subpixel having a light-emitting device that can be used as a light source. For example, it is preferable that one of the subpixels 110d and 110e is a subpixel IR that emits infrared light, and the other is a subpixel S having a light-receiving device that detects infrared light.

[0491] In a pixel having sub-pixels R, G, B, IR, and S, an image can be displayed using the sub-pixels R, G, and B, while the sub-pixel IR can be used as a light source to detect reflected infrared light emitted by the sub-pixel IR at the sub-pixel S.

[0492] As described above, in a display device according to one embodiment of the present invention, various layouts can be applied to pixels configured with subpixels each having a light-emitting device. Furthermore, in a display device according to one embodiment of the present invention, a pixel can have both a light-emitting device and a light-receiving device. Even in this case, various layouts can be applied.

[0493] This embodiment mode can be combined with other embodiment modes as appropriate.

[0494] Embodiment 5 In this embodiment, a display device according to one embodiment of the present invention will be described with reference to FIGS. 29A and 29B.

[0495] The display device of the present embodiment can be a high-definition display device, and can therefore be used, for example, as a display unit for a wristwatch-type or bracelet-type information terminal (wearable device), as well as a display unit for a wearable device that can be worn on the head, such as a head-mounted display (HMD) for VR, or a glasses-type AR device.

[0496] The display device of this embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of this embodiment can be used in electronic devices having relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[0497] 29A shows a perspective view of a display module 280. The display module 280 includes a display device 100A (described later) and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100A.

[0498] The display module 280 includes a substrate 291, a substrate 292, and a display portion 281. The display portion 281 is a region in the display module 280 where an image is displayed, and where light from pixels provided in a pixel portion 284 (described later) can be viewed.

[0499] 29B is a perspective view schematically illustrating the configuration on the substrate 291 side. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked on the substrate 291. A terminal portion 285 for connecting to the FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 may have a connection portion. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0500] The pixel portion 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of Fig. 29B. The pixel 284a in Fig. 29B is illustrated as having a configuration similar to that of the pixel 110 shown in Fig. 1A. Note that the various configurations described in the previous embodiments can be applied to the pixel 284a in Fig. 29B.

[0501] The pixel circuit portion 283 has a plurality of pixel circuits 283a arranged periodically. The pixel circuits 283a are exemplified as having the same configuration as the pixel circuit described in Embodiment 3. For example, the pixel circuit 283a can have at least one selection transistor, one current control transistor (drive transistor), and a capacitor per light-emitting device. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to the source. This realizes an active matrix display device.

[0502] The circuit portion 282 includes a circuit for driving each pixel circuit 283 a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0503] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit portion 282. In addition, an IC can be mounted on the FPC 290.

[0504] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are provided overlapping below the pixel unit 284, thereby enabling the aperture ratio (effective display area ratio) of the display unit 281 to be extremely high. For example, the aperture ratio of the display unit 281 can be 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, the pixels 284a can be arranged at an extremely high density, enabling the resolution of the display unit 281 to be extremely high. For example, it is preferable that the pixels 284a be arranged in the display unit 281 at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20,000 ppi or less, or 30,000 ppi or less.

[0505] Because such a display module 280 has extremely high resolution, it can be suitably used in VR devices such as HMDs or eyeglass-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display unit 281, so even when the display unit is enlarged with lenses, the pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices with relatively small displays. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0506] 30A and 30B can be applied to the display module of Fig. 29A. The display device 100A shown in Fig. 30A and 30B includes a substrate 301, a light-emitting device 130R, a light-emitting device 130G, a light-emitting device 130B, a capacitor 240, a transistor 310, and a transistor 253.

[0507] 29A and 29B. The laminated structure from the substrate 301 to the insulating layer 104 corresponds to the layer 101 in the first embodiment.

[0508] The transistor 310 has a channel formation region in a substrate 301. The substrate 301 can be a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as one of a source and a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0509] An isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0510] An insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0511] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0512] The use of a material with low light transmittance for the conductive layer 241 and the conductive layer 245 can prevent light from entering the transistor 310. When the conductive layer 241 and the conductive layer 245 function as light-shielding layers in addition to the light-shielding layer 109, fluctuations in the electrical characteristics of the transistor 310 are suppressed, and a highly reliable display device can be obtained. It is more preferable that one or both of the conductive layer 241 and the conductive layer 245 have a region overlapping with the transistor 310 (particularly, a channel formation region).

[0513] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 by a plug 271 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0514] Note that at least one of the conductive layers included in the layer 101 preferably includes a conductive layer surrounding the outside of the pixel portion 284. The conductive layer may also be called a guard ring. By providing the conductive layer, it is possible to prevent elements such as transistors and light-emitting devices from being damaged by a high voltage applied to these elements due to charging caused by electrostatic discharge (ESD) or a process using plasma.

[0515] An insulating layer 255 is provided to cover the capacitor 240, and transistors 253R, 253G, and 253H are provided on the insulating layer 255. Plugs 256R, 256G, and 256B are provided on the transistors 253R, 253G, and 253H. Light-emitting devices 130R, 130G, and 130B are provided on the plugs 256R, 256G, and 256B. A light-shielding layer 109 is provided between adjacent pixel electrodes 111.

[0516] 30A and 30B show an example in which the configurations of the pixel electrodes 111R, 111G, 111B, transistors 253R, 253G, 253B, plugs 256R, 256G, and plugs 256B shown in FIG. 1B are applied.

[0517] An inorganic insulating film such as an insulating oxide film, an insulating nitride film, an insulating oxynitride film, or an insulating nitride oxide film can be preferably used for the insulating layer 255. For example, one or more selected from a silicon oxide film, a silicon oxynitride film, and an aluminum oxide film can be preferably used.

[0518] In FIG. 30B , insulating layers 255a, 255b, and 255c are provided over the insulating layer 255. For the insulating layers 255a, 255b, and 255c, inorganic insulating films such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film can be preferably used. For the insulating layers 255a and 255c, an oxide insulating film or an oxynitride insulating film can be preferably used. For the insulating layers 255a and 255c, one or more of a silicon oxide film, a silicon oxynitride film, and an aluminum oxide film can be preferably used. For the insulating layer 255b, a nitride insulating film or a nitride oxide insulating film can be preferably used. For the insulating layer 255b, one or more of a silicon nitride film and a silicon nitride oxide film can be preferably used. More specifically, for the insulating layers 255a and 255c, silicon oxide films are preferably used, and for the insulating layer 255b, a silicon nitride film can be preferably used. The inorganic insulating film, such as silicon nitride, can suppress moisture transfer. An insulating layer containing silicon nitride may be disposed near the pixel electrode 111, but in order to form the light-shielding layer 109, it is preferable to use silicon nitride for the insulating layer 255b or the like below the insulating layer 104.

[0519] A mask layer 118R is located on the EL layer 113R of the light-emitting device 130R, a mask layer 118G is located on the EL layer 113G of the light-emitting device 130G, and a mask layer 118B is located on the EL layer 113B of the light-emitting device 130B.

[0520] The transistor 253R, the transistor 253G, and the transistor 253B are electrically connected to one of the source and drain of the transistor 310 via an insulating layer 243, a plug 256 embedded in the insulating layer 255, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. The height of the top surface of the insulating layer 255 and the height of the top surface of the plug 256 are the same or approximately the same. Various conductive materials can be used for the plug.

[0521] A protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. A substrate 120 is bonded to the protective layer 131 with a resin layer 122. For details of the components from the light-emitting devices to the substrate 120, refer to Embodiment 1. The substrate 120 corresponds to the substrate 292 in FIG. 29A .

[0522] [Display Device 100B] A display device 100B shown in FIG. 31 can be applied to the display module of FIG. 29A.

[0523] 31, the display device 100B can be provided with a lens array 133. The lens array 133 can be provided so as to overlap the light-emitting device 130. Light from the light-emitting device 130 passes through the lens array 133 and is extracted to the outside of the display device.

[0524] 31 shows an example in which a resin layer 122 is formed on the light-emitting devices 130R, 130G, and 130G, a protective layer 131b is formed thereon, and a lens array 133 is provided on the protective layer 131b. By forming the lens array 133 directly on the substrate on which the light-emitting devices are formed, it is possible to improve the accuracy of alignment between the light-emitting devices and the lens array.

[0525] The substrate 120 can be attached onto the lens array 133 via the resin layer 122b. By providing the lens array 133 on the substrate 120, the temperature of the heat treatment in the process of forming the lens array 133 can be increased.

[0526] The other configurations are the same as those in FIG. 30A, and therefore will not be described.

[0527] [Display Device 100C] A display device 100B shown in FIG. 32 can be applied to the display module of FIG. 29A.

[0528] 32 has a configuration in which a transistor 310A and a transistor 310B, each having a channel formed in a semiconductor substrate, are stacked. Note that in the following description of the display device, description of parts that are the same as those of the display device described above may be omitted.

[0529] The display device 100B has a configuration in which a substrate 301B on which a transistor 310B, a capacitor 240, and a light-emitting device are provided and a substrate 301A on which a transistor 310A is provided are bonded together.

[0530] Here, it is preferable to provide an insulating layer 345 on the lower surface of the substrate 301B. It is also preferable to provide an insulating layer 346 on the insulating layer 261 provided on the substrate 301A. The insulating layers 345 and 346 are insulating layers that function as protective layers and can suppress the diffusion of impurities into the substrates 301B and 301A. The insulating layers 345 and 346 can be made of an inorganic insulating film that can be used for the protective layer 131.

[0531] The substrate 301B is provided with a plug 343 that penetrates the substrate 301B and an insulating layer 345. Here, it is preferable to provide an insulating layer 344 to cover the side surface of the plug 343. The insulating layer 344 is an insulating layer that functions as a protective layer and can suppress the diffusion of impurities into the substrate 301B. The insulating layer 344 can be made of an inorganic insulating film that can be used for the protective layer 131.

[0532] A conductive layer 342 is provided on the back surface (surface opposite to the substrate 120 side) of the substrate 301B, below the insulating layer 345. The conductive layer 342 is preferably provided so as to be embedded in the insulating layer 335. The lower surfaces of the conductive layer 342 and the insulating layer 335 are preferably flattened. Here, the conductive layer 342 is electrically connected to the plug 343.

[0533] On the other hand, in the substrate 301A, a conductive layer 341 is provided on an insulating layer 346. The conductive layer 341 is preferably provided so as to be embedded in the insulating layer 336. In addition, the upper surfaces of the conductive layer 341 and the insulating layer 336 are preferably flattened.

[0534] The substrate 301A and the substrate 301B are electrically connected by bonding the conductive layer 341 and the conductive layer 342. Here, by improving the flatness of the surface formed by the conductive layer 342 and the insulating layer 335 and the surface formed by the conductive layer 341 and the insulating layer 336, the conductive layer 341 and the conductive layer 342 can be favorably bonded to each other.

[0535] It is preferable that the conductive layers 341 and 342 be made of the same conductive material. For example, a metal film containing an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, or a metal nitride film containing the above elements (titanium nitride film, molybdenum nitride film, tungsten nitride film), etc., can be used. In particular, it is preferable that copper be used for the conductive layers 341 and 342. This allows the application of Cu-Cu direct bonding technology (technology that achieves electrical conductivity by connecting Cu (copper) pads together).

[0536] The other configurations are the same as those in FIG. 30A, and therefore will not be described.

[0537] [Transistor] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate or bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0538] A transistor has a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The transistor can be driven by connecting the two gates and supplying the same signal to them. Alternatively, the threshold voltage of the transistor can be controlled by applying a potential to one of the two gates for controlling the threshold voltage and a potential to the other for driving.

[0539] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystal semiconductor, and a semiconductor having crystallinity other than a single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single-crystal semiconductor or a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0540] The semiconductor layer of the transistor preferably includes a metal oxide (oxide semiconductor). That is, the display device of this embodiment preferably includes a transistor using a metal oxide for a channel formation region (hereinafter referred to as an OS transistor).

[0541] Examples of crystalline oxide semiconductors include c-axis-aligned crystalline (CAAC)-OS and nanocrystalline (nc)-OS.

[0542] Alternatively, a transistor using silicon for a channel formation region (Si transistor) can be used. Examples of silicon include single crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, a transistor having low temperature polysilicon (LTPS) in a semiconductor layer (hereinafter also referred to as an LTPS transistor) can be used. An LTPS transistor has high field-effect mobility and favorable frequency characteristics.

[0543] By using Si transistors such as LTPS transistors, circuits that need to be driven at high frequencies (such as source driver circuits) can be built on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0544] An OS transistor has significantly higher field-effect mobility than a transistor using amorphous silicon. Furthermore, an OS transistor has significantly lower source-drain leakage current (also referred to as off-state current) in an off state and can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display device.

[0545] To increase the light emission luminance of a light-emitting device included in a pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, it is necessary to increase the source-drain voltage of a driving transistor included in the pixel circuit. Since an OS transistor has a higher source-drain breakdown voltage than a Si transistor, a high voltage can be applied between the source and drain of the OS transistor. Therefore, by using an OS transistor as the driving transistor included in the pixel circuit, it is possible to increase the amount of current flowing through the light-emitting device and increase the light emission luminance of the light-emitting device.

[0546] When a transistor operates in the saturation region, an OS transistor can reduce the change in source-drain current with respect to a change in gate-source voltage compared to a Si transistor. Therefore, by using an OS transistor as a driving transistor included in a pixel circuit, the current flowing between the source and drain can be precisely controlled by changing the gate-source voltage, thereby controlling the amount of current flowing through the light-emitting device. This allows for a larger number of gray levels to be displayed in the pixel circuit.

[0547] In terms of the saturation of the current that flows when a transistor operates in the saturation region, an OS transistor can pass a more stable current (saturation current) than a Si transistor, even when the source-drain voltage gradually increases. Therefore, by using an OS transistor as a driving transistor, a stable current can be passed through a light-emitting device, even when the current-voltage characteristics of the EL device vary. In other words, when an OS transistor operates in the saturation region, the source-drain current of the OS transistor remains almost unchanged even when the source-drain voltage increases, thereby stabilizing the light-emitting luminance of the light-emitting device.

[0548] As described above, by using an OS transistor for a driving transistor included in a pixel circuit, it is possible to achieve "suppression of black floating," "increase in light emission luminance," "multiple gradations," "suppression of variations in light-emitting devices," and the like.

[0549] Examples of metal oxides used in the semiconductor layer include indium oxide, gallium oxide, and zinc oxide. The metal oxide preferably contains at least indium or zinc. The metal oxide preferably contains one or more elements selected from indium, element M, and zinc. The element M is a metal element or semimetal element having a high bond energy with oxygen, for example, a metal element or semimetal element having a bond energy with oxygen higher than that of indium. Specific examples of the element M include aluminum, gallium, tin, yttrium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, zirconium, molybdenum, hafnium, tantalum, tungsten, lanthanum, cerium, neodymium, magnesium, calcium, strontium, barium, boron, silicon, germanium, and antimony. The element M contained in the metal oxide is preferably one or more of the above elements, more preferably one or more selected from gallium, aluminum, tin, and yttrium, and even more preferably one or more of gallium, aluminum, and tin. These elements are more preferred because they have a high bond energy with oxygen and an ionic radius similar to that of indium or zinc. Furthermore, tin is more preferred because it is tetravalent and can increase carrier mobility. In this specification, metal elements and metalloid elements may be collectively referred to as "metal elements," and the "metal elements" described in this specification may also include metalloid elements.

[0550] The semiconductor layer may be formed of, for example, indium zinc oxide (In-Zn oxide, also referred to as IZO (registered trademark)), indium tin oxide (In-Sn oxide, also referred to as ITO), indium titanium oxide (In-Ti oxide), indium gallium oxide (In-Ga oxide), indium tungsten oxide (In-W oxide, also referred to as IWO), indium gallium aluminum oxide (In-Ga-Al oxide), indium gallium tin oxide (In-Ga-Sn oxide, also referred to as IGTO), gallium zinc oxide (Ga-Zn oxide, also referred to as GZO), aluminum zinc oxide (Al-Zn oxide, Examples of usable materials include indium aluminum zinc oxide (In-Al-Zn oxide, also referred to as IAZO), indium tin zinc oxide (In-Sn-Zn oxide, also referred to as ITZO (registered trademark)), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium zinc oxide (In-Ga-Zn oxide, also referred to as IGZO), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide, also referred to as IGZTO), and indium gallium aluminum zinc oxide (In-Ga-Al-Zn oxide, also referred to as IGAZO, IGZAO, or IAGZO). Alternatively, examples of usable materials include indium tin oxide containing silicon (ITSO), gallium tin oxide (Ga-Sn oxide), and aluminum tin oxide (Al-Sn oxide).

[0551] Note that the metal oxide may contain one or more metal elements having a higher period number in the periodic table instead of or in addition to indium. The greater the overlap of the orbitals of metal elements, the greater the carrier conduction in the metal oxide. Therefore, the presence of a metal element having a higher period number may improve the field-effect mobility of a transistor. Examples of metal elements having a higher period number include metal elements belonging to the fifth period and the sixth period. Specific examples of such metal elements include yttrium, zirconium, silver, cadmium, tin, antimony, barium, lead, bismuth, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and europium. Lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and europium are called light rare earth elements.

[0552] By increasing the ratio of the number of indium atoms to the total number of atoms of all metal elements contained in the metal oxide, the field-effect mobility of the transistor can be increased, and a transistor with a large on-state current can be realized.

[0553] In this specification and the like, the ratio of the number of indium atoms to the sum of the numbers of atoms of all contained metal elements may be referred to as the indium content. The same applies to other metal elements. When a plurality of elements are contained as the element M, the sum of the ratios of the number of atoms of the element M to the sum of the numbers of atoms of all contained metal elements can be referred to as the content of the element M.

[0554] By increasing the zinc content in the metal oxide, the metal oxide can be made highly crystalline, which can suppress the diffusion of impurities in the metal oxide, thereby suppressing fluctuations in the electrical characteristics of the transistor and improving its reliability.

[0555] By increasing the content of element M in the metal oxide, it is possible to obtain a metal oxide with a large band gap. Ｏ ) is suppressed, the formation of oxygen vacancies (V Ｏ) can be suppressed, and a shift in the threshold voltage of the transistor can be suppressed. As a result, the cutoff current can be reduced, resulting in a normally-off transistor. Furthermore, the transistor can have a small off-state current. Furthermore, fluctuations in the electrical characteristics of the transistor can be suppressed, resulting in improved reliability.

[0556] The electrical characteristics and reliability of a transistor vary depending on the composition of the metal oxide used in the semiconductor layer. Therefore, by varying the composition of the metal oxide depending on the electrical characteristics and reliability required of the transistor, a semiconductor device that has both excellent electrical characteristics and high reliability can be obtained.

[0557] When the metal oxide is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of the element M. Examples of atomic ratios of metal elements in such In-M-Zn oxides include In:M:Zn = 1:1:1, In:M:Zn = 1:1:1.2, In:M:Zn = 2:1:3, In:M:Zn = 3:1:1, In:M:Zn = 3:1:2, In:M:Zn = 4:2:3, In:M:Zn = 4:2:4.1, In:M:Zn = 5:1:3, In:M:Zn = 5:1:6, In:M:Zn = 5:1:7, In:M:Zn = 5:1:8, In:M Examples of the composition include In:M:Zn = 5:1:9, In:M:Zn = 6:1:6, In:M:Zn = 10:1:1, In:M:Zn = 10:1:3, In:M:Zn = 10:1:4, In:M:Zn = 10:1:6, In:M:Zn = 10:1:7, In:M:Zn = 10:1:8, In:M:Zn = 5:2:5, In:M:Zn = 10:1:10, In:M:Zn = 20:1:10, In:M:Zn = 40:1:10, and compositions in the vicinity thereof. Note that in this specification, a composition in the vicinity includes a range of ±30% of the desired atomic ratio. Increasing the atomic ratio of indium in the metal oxide can increase the on-current or field-effect mobility of the transistor.

[0558] The atomic ratio of In in the In-M-Zn oxide can be less than the atomic ratio of the element M. Examples of atomic ratios of metal elements in such In-M-Zn oxide include In:M:Zn=1:3:2, In:M:Zn=1:3:3, In:M:Zn=1:3:4, In:M:Zn=1:3:6, and compositions close to these. By increasing the ratio of the number of M atoms in the metal oxide, oxygen deficiency (V Ｏ ) can be suppressed.

[0559] When the element M contains a plurality of elements, the atomic ratio of the element M can be the sum of the atomic ratios of these elements.

[0560] By using a material with a high indium content for the semiconductor layer, the on-state current or field-effect mobility of the transistor can be increased. Furthermore, by containing the element M, oxygen vacancies (V Ｏ ) can be suppressed. The content of element M in the metal oxide of the semiconductor layer is preferably 0.1% to 25% inclusive, more preferably 0.1% to 20% inclusive, even more preferably 0.1% to 10% inclusive, even more preferably 0.1% to 8% inclusive, even more preferably 0.1% to 6% inclusive, and even more preferably 0.1% to 4% inclusive. This allows for a transistor with excellent electrical characteristics. For example, it is preferable to use a metal oxide having a composition of In:M:Zn = 40:1:10 or thereabouts. The element M is preferably one or more of the above elements, and more preferably one or more selected from aluminum, gallium, tin, and yttrium. Specifically, a metal oxide having a composition of In:Sn:Zn = 40:1:10 or thereabouts can be suitably used. Alternatively, a metal oxide having a composition of In:Al:Zn = 40:1:10 or thereabouts can be suitably used.

[0561] Here, when a polycrystalline metal oxide is used for the semiconductor layer, crystal grain boundaries become recombination centers, which may capture carriers and reduce the on-state current of the transistor. Furthermore, when a polycrystalline metal oxide is used for the semiconductor layer, the surface of the semiconductor layer may become uneven. This may increase the step on the surface on which a layer formed on the semiconductor layer is formed, which may cause defects such as discontinuities or voids in the layer. When a metal oxide having a composition that easily forms a polycrystalline structure is used for the semiconductor layer, it is preferable to include an element that inhibits crystallization. This prevents the semiconductor layer from becoming a polycrystalline structure, resulting in a transistor with a large on-state current. Furthermore, the coverage of a layer formed on the semiconductor layer can be improved, which may prevent defects such as discontinuities or voids in the layer.

[0562] For example, compared with indium tin oxide (ITO), indium tin oxide containing silicon (ITSO) is less likely to form a polycrystalline structure, and therefore is suitable for use in the semiconductor layer. When ITSO is used, the silicon content is preferably 1% or more and 20% or less, more preferably 3% or more and 20% or less, even more preferably 3% or more and 15% or less, and even more preferably 5% or more and 15% or less. Specifically, metal oxides having compositions of In:Sn:Si=45:5:4, In:Sn:Si=95:5:8, or similar compositions can be suitably used. When indium tin oxide containing silicon (ITSO) is used in the semiconductor layer, it is preferable that it has crystallinity. Note that the semiconductor layer may have an amorphous region or may be amorphous.

[0563] A metal oxide that does not contain element M can be used for the semiconductor layer. When the metal oxide is an In-Zn oxide, the atomic ratio of the metal elements can be, for example, In:Zn = 1:1, In:Zn = 2:1, In:Zn = 1:2, In:Zn = 3:1, In:Zn = 3:2, In:Zn = 2:3, In:Zn = 4:1, In:Zn = 4:3, In:Zn = 5:1, In:Zn = 5:2, In:Zn = 5:3, In:Zn = 5:4, In:Zn = 5:6, In:Zn = 5:7, In:Zn = 5:8, In:Zn = 5:9, In:Zn = 7:1, In:Zn = 10:1, In:Zn = 10:3, In:Zn = 10:7, or compositions close to these. Furthermore, it is more preferable that the atomic ratio of In is equal to or greater than the atomic ratio of Zn. By increasing the atomic ratio of indium in the metal oxide, the on-state current or field-effect mobility of the transistor can be increased.

[0564] The composition of the semiconductor layer can be analyzed using, for example, energy dispersive X-ray spectrometry (EDX), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MS), or inductively coupled plasma atomic emission spectrometry (ICP-AES). Alternatively, a combination of these techniques can be used for analysis. It is preferable to separate the peaks of the spectrum obtained by the analysis and identify and quantify the elements. Note that for elements with low content, the actual content may differ from the content obtained by analysis due to the influence of analytical accuracy. For example, if the content of element M is low, the content of element M obtained by analysis may be lower than the actual content, it may be difficult to quantify the content of element M, or element M may not be detected.

[0565] The metal oxide can be preferably formed by sputtering or atomic layer deposition (ALD). Thermal ALD or PEALD can be used as the ALD. When forming a metal oxide by sputtering, the composition of the formed metal oxide may differ from that of the sputtering target. In particular, the zinc content in the formed metal oxide may be reduced to about 50% of that of the sputtering target. Alternatively, the PECVD method can be used to form the metal oxide.

[0566] The semiconductor layer is preferably made of a crystalline metal oxide. Examples of the structure of the crystalline metal oxide include a c-axis aligned crystal (CAAC) structure, a polycrystalline structure, and a nanocrystalline (nc) structure. By using a crystalline metal oxide, the density of defect states in the semiconductor layer can be reduced, and a highly reliable semiconductor device can be realized.

[0567] The semiconductor layer is preferably formed using a CAAC-OS or an nc-OS.

[0568] The CAAC-OS has multiple layered crystals whose c-axes are oriented in the normal direction to the surface where the semiconductor layer is formed. The semiconductor layer preferably has layered crystals that are parallel or substantially parallel to the surface where the semiconductor layer is formed. This allows the layered crystals of the semiconductor layer to be formed substantially parallel to the channel length direction of the transistor, thereby enabling the transistor to have a large on-state current.

[0569] By using a metal oxide with high crystallinity for the channel formation region, the density of defect states in the channel formation region can be reduced, while by using a metal oxide with low crystallinity, a transistor capable of passing a large current can be realized.

[0570] As described above, a display device according to one embodiment of the present invention can have a high aperture ratio, high definition, high display quality, and low power consumption.

[0571] A display device according to one embodiment of the present invention includes an OS transistor and a light-emitting device with a metal maskless (MML) structure. This structure can significantly reduce leakage current that may flow through the transistor and leakage current that may flow between adjacent light-emitting devices (also referred to as lateral leakage current or side leakage current). Furthermore, when an image is displayed on the display device, the viewer can observe one or more of image clarity, image sharpness, high saturation, and a high contrast ratio. The extremely low leakage current that may flow through the transistor and lateral leakage current between the light-emitting devices can minimize light leakage during black display (so-called floating black).

[0572] In particular, among light-emitting devices with an MML structure, by applying the SBS structure described above, the layers provided between the light-emitting devices (for example, organic layers shared between the light-emitting devices, also called common layers) are configured to be separated, thereby eliminating side leakage or making it possible to greatly reduce side leakage.

[0573] This embodiment mode can be combined with other embodiment modes as appropriate.

[0574] Embodiment 6 In this embodiment, a light-emitting device that can be used for a display device according to one embodiment of the present invention will be described.

[0575] 33A, the light-emitting device has an EL layer 763 between a pair of electrodes (a lower electrode 761 and an upper electrode 762). The EL layer 763 can be composed of multiple layers, such as a layer 780, a light-emitting layer 771, and a layer 790.

[0576] The light-emitting layer 771 contains at least a light-emitting substance (also referred to as a light-emitting material).

[0577] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, the layer 780 includes one or more of a layer containing a substance with high hole-injecting properties (hole-injecting layer), a layer containing a substance with high hole-transporting properties (hole-transporting layer), and a layer containing a substance with high electron-blocking properties (electron-blocking layer). The layer 790 also includes one or more of a layer containing a substance with high electron-injecting properties (electron-injecting layer), a layer containing a substance with high electron-transporting properties (electron-transporting layer), and a layer containing a substance with high hole-blocking properties (hole-blocking layer). When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, the layers 780 and 790 have the opposite structures to those described above.

[0578] A structure including the layer 780, the light-emitting layer 771, and the layer 790 provided between a pair of electrodes can function as a single light-emitting unit, and the structure of FIG. 33A is referred to as a single structure in this specification.

[0579] Fig. 33B shows a modified example of the EL layer 763 included in the light-emitting device shown in Fig. 33A. Specifically, the light-emitting device shown in Fig. 33B has a layer 781 on a lower electrode 761, a layer 782 on the layer 781, a light-emitting layer 771 on the layer 782, a layer 791 on the light-emitting layer 771, a layer 792 on the layer 791, and an upper electrode 762 on the layer 792.

[0580] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, for example, the layer 781 can be a hole injection layer, the layer 782 can be a hole transport layer, the layer 791 can be an electron transport layer, and the layer 792 can be an electron injection layer. When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, the layer 781 can be an electron injection layer, the layer 782 can be an electron transport layer, the layer 791 can be a hole transport layer, and the layer 792 can be a hole injection layer. Such a layer structure allows carriers to be efficiently injected into the light-emitting layer 771, and the efficiency of carrier recombination in the light-emitting layer 771 can be increased.

[0581] 33C and 33D, a variation of the single structure is a configuration in which multiple light-emitting layers (light-emitting layers 771, 772, and 773) are provided between layer 780 and layer 790. While an example having three light-emitting layers is shown in FIGS. 33C and 33D, the number of light-emitting layers in a single-structure light-emitting device may be two, or may be four or more. Furthermore, a light-emitting device with a single structure may have a buffer layer between the two light-emitting layers.

[0582] As shown in Figures 33E and 33F, a structure in which a plurality of light-emitting units (light-emitting unit 763a and light-emitting unit 763b) are connected in series via a charge generation layer 785 (also referred to as an intermediate layer) is referred to as a tandem structure in this specification. Note that a tandem structure can also be referred to as a stack structure. By using a tandem structure, a light-emitting device capable of emitting high-luminance light can be obtained. Furthermore, compared to a single structure, a tandem structure can reduce the current required to obtain the same luminance, thereby improving reliability.

[0583] 33D and 33F show examples of a display device having a layer 764 overlapping with the light-emitting device. Fig. 33D shows an example in which the layer 764 overlaps with the light-emitting device shown in Fig. 33C, and Fig. 33F shows an example in which the layer 764 overlaps with the light-emitting device shown in Fig. 33E. In Fig. 33D and 33F, a conductive film that transmits visible light is used for the upper electrode 762 in order to extract light to the upper electrode 762 side.

[0584] As the layer 764, one or both of a color conversion layer and a color filter (coloring layer) can be used.

[0585] 33C and 33D , the light-emitting layers 771, 772, and 773 may be made of light-emitting materials that emit light of the same color, or even the same light-emitting material. For example, the light-emitting layers 771, 772, and 773 may be made of a light-emitting material that emits blue light. In the subpixel that emits blue light, blue light emitted by the light-emitting device can be extracted. In the subpixel that emits red light and the subpixel that emits green light, a color conversion layer is provided as the layer 764 shown in FIG. 33D to convert blue light emitted by the light-emitting device into light with a longer wavelength, thereby allowing red or green light to be extracted.

[0586] The light-emitting layer 771, the light-emitting layer 772, and the light-emitting layer 773 may each include a light-emitting substance emitting light of a different color. A structure can be obtained in which white light is emitted by mixing the lights emitted by the light-emitting layer 771, the light-emitting layer 772, and the light-emitting layer 773. For example, a light-emitting device with a single structure preferably includes a light-emitting layer having a light-emitting substance that emits blue light and a light-emitting layer having a light-emitting substance that emits visible light with a wavelength longer than blue.

[0587] For example, when a light-emitting device with a single structure has three light-emitting layers, it preferably has a light-emitting layer containing a light-emitting material that emits red (R) light, a light-emitting layer containing a light-emitting material that emits green (G) light, and a light-emitting layer containing a light-emitting material that emits blue (B) light. The stacking order of the light-emitting layers may be R, G, B from the anode side, or R, B, G from the anode side, etc. In this case, a buffer layer may be provided between R and G or B.

[0588] For example, when a light-emitting device with a single structure has two light-emitting layers, it is preferable to have one light-emitting layer containing a light-emitting material that emits blue light and another light-emitting layer containing a light-emitting material that emits yellow light.

[0589] A color filter may be provided as layer 764 shown in Figure 33D. When white light passes through the color filter, light of a desired color can be obtained.

[0590] A light-emitting device that emits white light preferably contains two or more types of light-emitting materials. To obtain white light emission, it is preferable to select light-emitting materials such that the light emitted by the two light-emitting materials has a complementary color relationship, or to select light-emitting materials such that the light emitted by the two or more light-emitting materials combine to produce white light. For example, when white light emission is obtained using two light-emitting layers, a light-emitting device that emits white light as a whole can be obtained by making the emission colors of the two light-emitting layers complementary to each other. Furthermore, when white light emission is obtained using three or more light-emitting layers, it is preferable to configure the light-emitting device so that the emission colors of the three or more light-emitting layers combine to produce white light as a whole.

[0591] 33E and 33F, the light-emitting layer 771 and the light-emitting layer 772 may be made of a light-emitting material that emits light of the same color, or even the same light-emitting material.

[0592] For example, in the light-emitting devices included in the subpixels emitting light of each color, a light-emitting material emitting blue light may be used for the light-emitting layers 771 and 772. In the subpixel emitting blue light, the blue light emitted by the light-emitting device can be extracted. In the subpixels emitting red light and the subpixels emitting green light, a color conversion layer is provided as the layer 764 shown in FIG. 33F to convert the blue light emitted by the light-emitting device into light with a longer wavelength, thereby allowing red or green light to be extracted.

[0593] When the light-emitting devices having the configurations shown in FIG. 33E or 33F are used for the subpixels emitting light of each color, different light-emitting materials may be used for each subpixel. Specifically, in a light-emitting device included in a subpixel emitting red light, light-emitting layers 771 and 772 may each contain a light-emitting material that emits red light. Similarly, in a light-emitting device included in a subpixel emitting green light, light-emitting layers 771 and 772 may each contain a light-emitting material that emits green light. In a light-emitting device included in a subpixel emitting blue light, light-emitting layers 771 and 772 may each contain a light-emitting material that emits blue light. A display device having such a configuration can be said to employ a tandem-structure light-emitting device and also have an SBS structure. Therefore, it can have the advantages of both the tandem structure and the SBS structure. This allows for a highly reliable light-emitting device capable of emitting high-brightness light.

[0594] 33E and 33F, light-emitting layers 771 and 772 may be made of light-emitting materials that emit light of different colors. When the light emitted by light-emitting layer 771 and the light emitted by light-emitting layer 772 are complementary colors, white light can be obtained. A color filter may be provided as layer 764 shown in FIG. 33F. When white light passes through the color filter, light of a desired color can be obtained.

[0595] 33E and 33F show an example in which the light-emitting unit 763a has one light-emitting layer 771 and the light-emitting unit 763b has one light-emitting layer 772, but this is not limiting. Each of the light-emitting unit 763a and the light-emitting unit 763b may have two or more light-emitting layers.

[0596] 33E and 33F show examples of light emitting devices having two light emitting units, but the light emitting device is not limited to this and may have three or more light emitting units.

[0597] Specifically, when a light-emitting device with a tandem structure is used, a two-stage tandem structure having a light-emitting unit that emits yellow light and a light-emitting unit that emits blue light, a two-stage tandem structure having a light-emitting unit that emits red and green light and a light-emitting unit that emits blue light, a three-stage tandem structure having a light-emitting unit that emits blue light, a light-emitting unit that emits yellow, yellow-green, or green light, and a light-emitting unit that emits blue light, in this order, or a three-stage tandem structure having a light-emitting unit that emits blue light, a light-emitting unit that emits yellow, yellow-green, or green light, and red light, and a light-emitting unit that emits blue light, in this order, or the like can be applied. For example, the number of stacked light-emitting units and the order of colors can be, from the anode side, a two-layer structure of B and Y, a two-layer structure of B and light-emitting unit X, a three-layer structure of B, Y, and B, and the number of stacked light-emitting layers in light-emitting unit X and the order of colors can be, from the anode side, a two-layer structure of R and Y, a two-layer structure of R and G, a two-layer structure of G and R, a three-layer structure of G, R, and G, or a three-layer structure of R, G, and R. Furthermore, another layer can be provided between the two light-emitting layers.

[0598] 33C and 33D, the layer 780 and the layer 790 may each independently have a laminated structure made up of two or more layers, as shown in FIG. 33B.

[0599] 33E and 33F, light-emitting unit 763a includes layer 780a, light-emitting layer 771, and layer 790a, and light-em...

Claims

a first light-emitting device, a first transistor electrically connected to the first light-emitting device, a second light-emitting device adjacent to the first light-emitting device, a second transistor electrically connected to the second light-emitting device, and a light-shielding layer on a substrate; the first light-emitting device has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer; the second light-emitting device has a second pixel electrode, a second EL layer on the second pixel electrode, and the common electrode on the second EL layer; A display device, wherein, in a cross-sectional view, the light-shielding layer has a region located between the first pixel electrode and the second pixel electrode, and an upper surface of the light-shielding layer is lower than an upper surface of the first pixel electrode. 　 a first light-emitting device, a first transistor electrically connected to the first light-emitting device, a second light-emitting device adjacent to the first light-emitting device, a second transistor electrically connected to the second light-emitting device, and a light-shielding layer on a substrate; the first light-emitting device has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer; the second light-emitting device has a second pixel electrode, a second EL layer on the second pixel electrode, and the common electrode on the second EL layer; a display device, wherein, in a cross-sectional view, the light-shielding layer has a region located between the first pixel electrode and the second pixel electrode, and a height from the substrate to an upper surface of the light-shielding layer is lower than a height from the substrate to an upper surface of the first pixel electrode. 　 a first light-emitting device, a first transistor electrically connected to the first light-emitting device, a second light-emitting device adjacent to the first light-emitting device, a second transistor electrically connected to the second light-emitting device, and a light-shielding layer on a substrate; the first light-emitting device has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer; the second light-emitting device has a second pixel electrode, a second EL layer on the second pixel electrode, and the common electrode on the second EL layer; a display device, wherein, in a cross-sectional view, the light-shielding layer has a region located between the first pixel electrode and the second pixel electrode, an upper surface of the light-shielding layer is lower than an upper surface of the first pixel electrode, and a film thickness of the light-shielding layer is thicker than a film thickness of the first pixel electrode. 　 a first light-emitting device, a first transistor electrically connected to the first light-emitting device, a second light-emitting device adjacent to the first light-emitting device, a second transistor electrically connected to the second light-emitting device, and a light-shielding layer on a substrate; the first light-emitting device has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer; the second light-emitting device has a second pixel electrode, a second EL layer on the second pixel electrode, and the common electrode on the second EL layer; a display device, wherein, in a cross-sectional view, the light-shielding layer has a region located between the first pixel electrode and the second pixel electrode, the height from the substrate to an upper surface of the light-shielding layer is lower than the height from the substrate to an upper surface of the first pixel electrode, and the film thickness of the light-shielding layer is thicker than the film thickness of the first pixel electrode. 　 In any one of claims 1 to 4, A display device, wherein, in a cross-sectional view, the light-shielding layer has an area in contact with a side surface of the first pixel electrode, but does not have an area in contact with a top surface of the first pixel electrode. 　 In any one of claims 1 to 4, The display device, wherein the light-shielding layer comprises an organic material. 　 In any one of claims 1 to 4, The display device, wherein the light-shielding layer has a transmittance of 50% or less for light having a wavelength of 300 nm or more and 550 nm or less. 　 In any one of claims 1 to 4, The display device, wherein the light-shielding layer has a region between the first pixel electrode and the second pixel electrode, the region having a thickness of 200 nm or more and 2000 nm or less. 　 In any one of claims 1 to 4, The display device, wherein the first pixel electrode has a function of reflecting visible light. 　 In any one of claims 1 to 4, The common electrode has a function of transmitting visible light. 　 In any one of claims 1 to 4, A display device, wherein, in a cross-sectional view, a side surface of the first EL layer has an area facing a side surface of the second EL layer. 　 A head-mounted display equipped with the display device according to any one of claims 1 to 4.

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