Display apparatus

Abstract

To provide: a display apparatus with a light sensing function; and a display apparatus with high light sensitivity.SOLUTION: The display apparatus includes a light-receiving element, a light-emitting element, a conductive layer, and a first wiring. The light-receiving element includes a first pixel electrode, a common layer, an active layer, and a common electrode. The light-emitting element includes a second pixel electrode, the common layer, a light-emitting layer, and the common electrode. The conductive layer is provided over the same surface as the first and second pixel electrodes, is positioned between the first and second pixel electrodes, is electrically connected to the common layer, and is electrically connected to the first wiring to which a first potential is supplied. The common layer includes a portion overlapping with the first pixel electrode, a portion overlapping with the second pixel electrode, and a portion overlapping with the conductive layer. The common electrode includes a portion overlapping with the first pixel electrode and a portion overlapping with the second pixel electrode. The first wiring is provided over a surface different from the surface where the conductive layer is provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect of the present invention relates to a display device, a display module, and an electronic device. One aspect of the present invention relates to a display device including a light-emitting element (also referred to as a light-emitting device) and a light-receiving element (also referred to as a light-receiving device). One aspect of the present invention relates to a display device having an authentication function. One aspect of the present invention relates to a touch panel. One aspect of the present invention relates to a system including a display device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention disclosed in this specification and the like include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, imaging devices, driving methods thereof, and manufacturing methods thereof. A semiconductor device refers to any device that can function by utilizing semiconductor characteristics. [Background technology]

[0003] In recent years, display devices have been expected to be used in a variety of applications. For example, large display devices are used in home television devices (also called televisions or television receivers), digital signage, public information displays (PIDs), etc. Furthermore, smartphones and tablet devices equipped with touch panels are being developed as mobile information terminals.

[0004] As a display device, for example, a light-emitting device having a light-emitting element has been developed. Light-emitting elements (also referred to as EL elements) that utilize the electroluminescence (hereinafter referred to as EL) phenomenon have features such as being easily made thin and lightweight, being capable of responding quickly to input signals, and being able to be driven using a DC constant voltage power supply, and are therefore applied to display devices. For example, Patent Document 1 discloses a flexible light-emitting device that uses an organic EL element. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-197522 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of one embodiment of the present invention is to provide a display device having a light detection function. Another object is to provide a highly reliable display device having a light detection function. Another object is to provide a multifunctional display device. Another object is to provide a display device with high display quality. Another object is to provide a display device with high light detection sensitivity. Another object is to provide a novel display device.

[0007] Another object of one embodiment of the present invention is to provide a display device with high light detection accuracy, a display device capable of capturing a clear image, or a display device having a function as a touch panel.

[0008] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description of the specification, drawings, claims, etc. [Means for solving the problem]

[0009] One embodiment of the present invention is a display device including a light-receiving element, a light-emitting element, a conductive layer, and a first wiring. The light-receiving element includes a first pixel electrode, a common layer over the first pixel electrode, an active layer over the common layer, and a common electrode over the active layer. The light-emitting element includes a second pixel electrode, a common layer over the second pixel electrode, a light-emitting layer over the common layer, and a common electrode over the light-emitting layer. The conductive layer is provided on the same plane as the first pixel electrode and the second pixel electrode, is positioned between the first pixel electrode and the second pixel electrode, and is electrically connected to the common layer and to a first wiring to which a first potential is applied. The common layer has a portion overlapping with the first pixel electrode, a portion overlapping with the second pixel electrode, and a portion overlapping with the conductive layer. The common electrode has a portion overlapping with the first pixel electrode and a portion overlapping with the second pixel electrode. The first wiring is provided on a different plane from the conductive layer.

[0010] In the above, it is preferable to have a first transistor and a second transistor. It is also preferable that a second potential lower than the first potential is applied to the first pixel electrode via the first transistor. It is also preferable that a third potential higher than the first potential is applied to the second pixel electrode via the second transistor. It is also preferable that the first potential is applied to the common electrode.

[0011] Alternatively, in the above, a fourth potential equal to or higher than the first potential is preferably applied to the first pixel electrode via the first transistor, and a fifth potential equal to or higher than the first potential is preferably applied to the second pixel electrode via the second transistor, and the fifth potential is preferably higher than the fourth potential.

[0012] In the above, the conductive layer preferably has a ring-shaped first portion. In this case, the first pixel electrode is preferably located inside the first portion in a plan view. Alternatively, the second pixel electrode is preferably located inside the first portion.

[0013] Furthermore, in the above, when the liquid crystal display device has a plurality of first pixel electrodes and a plurality of second pixel electrodes, the conductive layer preferably has an annular first portion, an annular second portion, and a third portion. In this case, it is preferable that one of the plurality of first pixel electrodes is located inside the first portion in a planar view. It is also preferable that another of the plurality of first pixel electrodes is located inside the second portion in a planar view. It is also preferable that the third portion is located between the first portion and the second portion in a planar view. Alternatively, it is preferable that one of the plurality of second pixel electrodes is located inside the first portion in a planar view. It is also preferable that another of the plurality of second pixel electrodes is located inside the second portion in a planar view. It is also preferable that the third portion is located between the first portion and the second portion in a planar view.

[0014] In the above, when the liquid crystal display device has a plurality of first pixel electrodes and a plurality of second pixel electrodes, it is preferable that the plurality of first pixel electrodes are arranged in a first direction and the plurality of second pixel electrodes are arranged in the second direction. It is also preferable that the conductive layer extends in the first direction and has a portion located between the plurality of first pixel electrodes and the plurality of second pixel electrodes.

[0015] In the above, it is preferable that the display device has a display region and a non-display region. The plurality of first pixel electrodes and the plurality of second pixel electrodes are preferably provided in the display region. In this case, it is preferable that the conductive layer is provided across the display region and the non-display region and is electrically connected to the first wiring in the non-display region. It is more preferable that the conductive layer is electrically connected to the first wiring in the display region. Alternatively, it is preferable that the conductive layer is provided in the display region and is electrically connected to the first wiring in the display region.

[0016] In the above, the first wiring preferably has a portion overlapping with the first pixel electrode and a portion overlapping with the second pixel electrode, or the first wiring preferably has a portion located between the first pixel electrode and the second pixel electrode.

[0017] One aspect of the present invention is a module having a display device having any of the above configurations, and having a connector such as a flexible printed circuit (hereinafter referred to as FPC) or a TCP (Tape Carrier Package) attached, or a module having an integrated circuit (IC) mounted by a COG (Chip On Glass) method or a COF (Chip On Film) method, etc.

[0018] One embodiment of the present invention is an electronic device including the above-described module and at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button. [Effects of the Invention]

[0019] According to one embodiment of the present invention, a display device having a light detection function can be provided. Alternatively, a display device having a light detection function and high reliability can be provided. Alternatively, a multifunctional display device can be provided. Alternatively, a display device with high display quality can be provided. Alternatively, a display device with high light detection sensitivity can be provided. Alternatively, a novel display device can be provided.

[0020] According to one embodiment of the present invention, a display device with high light detection accuracy, a display device capable of capturing a clear image, or a display device having a function as a touch panel can be provided.

[0021] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these can be extracted from the description in the specification, drawings, claims, etc. [Brief explanation of the drawings]

[0022] [Figure 1] 1A and 1B are diagrams showing an example of the configuration of a display device. [Figure 2]Fig. 2A is a schematic diagram showing the relationship between voltage and current density, and Fig. 2B is a diagram illustrating the potential applied to the display device. [Figure 3] 3A to 3D are diagrams showing configuration examples of a display device. [Figure 4] 4A to 4C are diagrams showing configuration examples of a display device. [Figure 5] 5A and 5B are diagrams showing configuration examples of a display device. [Figure 6] 6A to 6C are diagrams showing configuration examples of a display device. [Figure 7] 7A and 7B are diagrams showing configuration examples of a display device. [Figure 8] 8A and 8B are cross-sectional views showing an example of the configuration of a display device. [Figure 9] 9A and 9B are diagrams showing configuration examples of a display device. [Figure 10] 10A and 10B are cross-sectional views showing configuration examples of a display device. [Figure 11] 11A and 11B are cross-sectional views showing configuration examples of a display device. [Figure 12] FIG. 12 is a diagram illustrating an example of the configuration of a display device. [Figure 13] 13A and 13B are diagrams showing configuration examples of a display device. [Figure 14] 14A, 14B, and 14D are cross-sectional views showing an example of a display device, 14C and 14E are diagrams showing examples of images captured by the display device, and 14F to 14H are top views showing examples of pixels. [Figure 15] 15A is a cross-sectional view showing an example of the configuration of a display device, and FIGS. 15B to 15D are top views showing an example of a pixel. [Figure 16] 16A is a cross-sectional view showing an example of the configuration of a display device, and FIGS. 16B to 16I are top views showing an example of a pixel. [Figure 17] 17A and 17B are diagrams showing configuration examples of a display device. [Figure 18]18A to 18G are diagrams showing configuration examples of the display device. [Figure 19] 19A to 19C are diagrams showing configuration examples of a display device. [Figure 20] 20A and 20B are diagrams showing configuration examples of a display device. [Figure 21] 21A and 21B are diagrams showing configuration examples of a display device. [Figure 22] FIG. 22 is a diagram showing an example of the configuration of a display device. [Figure 23] Fig. 23A is a diagram showing a configuration example of a display device, Fig. 23B and Fig. 23C are diagrams showing configuration examples of a transistor. [Figure 24] 24A and 24B are diagrams showing examples of pixel configurations, and Fig. 24C to Fig. 24E are diagrams showing examples of pixel circuit configurations. [Figure 25] 25A and 25B are diagrams showing configuration examples of electronic devices. [Figure 26] 26A to 26D are diagrams showing configuration examples of electronic devices. [Figure 27] 27A to 27F are diagrams showing configuration examples of electronic devices. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments will be described with reference to the drawings. However, it will be readily understood by those skilled in the art that the embodiments can be implemented in many different ways and that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the following description of the embodiments.

[0024] 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. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be assigned.

[0025] In the drawings described in this specification, the size of each component, the thickness of a layer, or an area may be exaggerated for clarity, and therefore, the drawings are not necessarily limited to the scale.

[0026] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components and do not limit the number.

[0027] In this specification and the like, a display panel, which is one aspect of a display device, has a function of displaying (outputting) images etc. on a display surface, and therefore the display panel is one aspect of an output device.

[0028] In addition, in this specification, a display panel having a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) attached to the substrate, or having an IC mounted on the substrate using a COG (Chip On Glass) method or the like, may be referred to as a display panel module, display module, or simply a display panel.

[0029] In this specification and the like, a touch panel, which is one aspect of a display device, has a function of displaying an image or the like on a display surface and a function as a touch sensor that detects that a detectable object such as a finger or a stylus touches, presses, or approaches the display surface. Thus, the touch panel is one aspect of an input / output device.

[0030] A touch panel can also be called, for example, a display panel (or display device) with a touch sensor or a display panel (or display device) with a touch sensor function. A touch panel can have a configuration including a display panel and a touch sensor panel. Alternatively, the touch panel can have a touch sensor function inside or on the surface of the display panel.

[0031] In addition, in this specification and the like, a touch panel substrate on which a connector, an IC, etc. are mounted may be called a touch panel module, a display module, or simply a touch panel.

[0032] (Embodiment 1) In this embodiment, a configuration example of one embodiment of the present invention will be described.

[0033] A device according to one embodiment of the present invention includes a plurality of light-receiving elements and a plurality of light-emitting elements. The light-receiving elements function as photoelectric conversion elements that detect light incident on the light-receiving elements and generate electric charges.

[0034] A device according to one embodiment of the present invention can capture an image using a plurality of light-receiving elements and therefore functions as an imaging device. In this case, the light-emitting elements can be used as a light source for capturing an image. Furthermore, a device according to one embodiment of the present invention can display an image using a plurality of light-emitting elements and therefore functions as a display device. Therefore, one embodiment of the present invention can be referred to as a display device having an imaging function or an imaging device having a display function.

[0035] For example, in a display device according to one embodiment of the present invention, light-emitting elements are arranged in a matrix in the display portion, and light-receiving elements are also arranged in a matrix in the display portion. Therefore, the display portion has a function of displaying an image and a function as a light-receiving portion. Since images can be captured by the light-receiving elements provided in the display portion, the display device can function as an image sensor, a touch panel, or the like. That is, the display portion can capture an image, detect the approach or contact of an object, and the like. For example, the display device can be used as an image scanner. Furthermore, since the light-emitting elements provided in the display portion can be used as a light source for receiving light, there is no need to provide a light source separately from the display device, and a highly functional display device can be realized without increasing the number of electronic components.

[0036] In the display device of one embodiment of the present invention, not only external light but also light emitted from a light-emitting element included in a display portion can be detected by a light-receiving element when the light is reflected (or scattered) by an object; therefore, imaging and detection of touch operations (including non-contact operations) are possible even in a dark place.

[0037] Furthermore, the display device of one embodiment of the present invention can capture an image of a fingerprint or palm print when a finger, palm, or the like is placed in contact with the display unit. Therefore, an electronic device equipped with the display device of one embodiment of the present invention can perform personal authentication using the captured image of a fingerprint, palm print, or the like. This eliminates the need for a separate imaging device for fingerprint authentication, palm print authentication, or the like, thereby reducing the number of components in the electronic device. Furthermore, since the light-receiving elements are arranged in a matrix on the display unit, an image of a fingerprint, palm print, or the like can be captured anywhere on the display unit, thereby realizing an electronic device with excellent convenience.

[0038] As the light-emitting element, it is preferable to use an EL element such as an OLED (Organic Light Emitting Diode) or a QLED (Quantum-dot Light Emitting Diode). Examples of light-emitting materials that the EL element has include a material that emits fluorescence (fluorescent material), a material that emits phosphorescence (phosphorescent material), a material that exhibits thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) material), and an inorganic compound (such as a quantum dot material).

[0039] As the light receiving element, for example, a pn-type or pin-type photodiode can be used. The light receiving element functions as a photoelectric conversion element that detects light incident on the light receiving element and generates an electric charge. The amount of electric charge generated by the photoelectric conversion element is determined according to the amount of incident light. In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light receiving element. Organic photodiodes can be easily made thin, lightweight, and large in area, and have a high degree of freedom in shape and design, so they can be applied to various display devices.

[0040] It is also preferable to use an organic compound for the active layer of the light-receiving element. In this case, it is preferable to provide one electrode of the light-emitting element and one electrode of the light-receiving element (each of which is also called a pixel electrode) on the same surface. Furthermore, it is more preferable that the other electrode of the light-emitting element and the other electrode of the light-receiving element be electrodes (also called a common electrode) formed of a continuous (continuous) conductive layer. Furthermore, it is more preferable that the light-emitting element and the light-receiving element have a common layer. The common layer is a layer used in common by both the light-emitting element and the light-receiving element. It is more preferable that the common layer is provided continuously (continuously) across both the light-emitting element and the light-receiving element.

[0041] For example, it is preferable that at least one of the hole injection layer, hole transport layer, electron transport layer, and electron injection layer be a common layer between the light receiving element and the light emitting element. Furthermore, the light receiving element and the light emitting element may have the same configuration, except that the light receiving element has an active layer and the light emitting element has an emitting layer. In other words, a light receiving element can be fabricated simply by replacing the emitting layer of the light emitting element with an active layer. By having the light receiving element and the light emitting element share a common layer, the number of film formations and the number of masks can be reduced, thereby reducing the manufacturing process and manufacturing costs of the display device. Furthermore, a display device having a light receiving element can be fabricated using existing manufacturing equipment and methods for display devices.

[0042] On the other hand, when a common layer is provided between the pixel electrode (also referred to as the first pixel electrode) of the light-receiving element and the active layer, and between the pixel electrode (also referred to as the second pixel electrode) of the light-emitting element and the light-emitting layer, and the light-emitting element and the light-receiving element share a common electrode, a current may flow from the second pixel electrode to the first pixel electrode via the common layer due to differences in the potentials applied to the respective pixel electrodes. Hereinafter, this current flowing between the pixel electrodes via the common layer is referred to as a side leakage current. Because the light-receiving element converts received light into an electrical signal and outputs it, the side leakage current becomes noise in the light-receiving element and reduces the signal-to-noise ratio (S / N). Therefore, the side leakage current may prevent clear image capture. Therefore, it is desirable to suppress side leakage while reducing the number of separate coatings by providing a common layer.

[0043] The light-emitting element and the light-receiving element each have diode characteristics. When a forward bias voltage is applied to the light-emitting element, a current flows through it and it emits light. On the other hand, when a reverse bias voltage is applied to the light-receiving element, an electric charge is generated according to the intensity of the light received through photoelectric conversion. Therefore, when a common electrode is used for the light-emitting element and the light-receiving element, the potential applied to the first pixel electrode when photoelectric conversion is performed by the light-receiving element and the potential applied to the second pixel electrode when the light-emitting element emits light may be higher and lower than the potential applied to the common electrode, resulting in a large potential difference. This potential difference may cause side leakage current between the first pixel electrode and the second pixel electrode.

[0044] For example, if the common electrode serves as the cathode of the light-receiving element and the light-emitting element, a potential lower than that of the common electrode is applied to the first pixel electrode of the light-receiving element, and a potential higher than that of the common electrode is applied to the second pixel electrode of the light-emitting element. In this case, side leakage current flows from the second pixel electrode to the first pixel electrode through the common layer. It is preferable that a different transistor is connected to each pixel electrode. In this case, any potential can be applied to the pixel electrode via the transistor.

[0045] Therefore, one embodiment of the present invention provides a structure in which a conductive layer electrically connected to the common layer is provided between the first pixel electrode and the second pixel electrode. The conductive layer is located on a path of a side leakage current flowing from the second pixel electrode to the first pixel electrode, and is provided so that the side leakage current flows into the conductive layer. This makes it possible to block the side leakage current.

[0046] The conductive layer is preferably provided on the same plane as the first pixel electrode and the second pixel electrode. The conductive layer is preferably electrically connected to a wiring (also referred to as a first wiring) and a first potential is applied to the conductive layer through the wiring. By setting the first potential lower than the potential applied to the second pixel electrode, a side leakage current flowing from the second pixel to the first pixel can be made to flow through the conductive layer. As a result, the side leakage current can be effectively suppressed, noise in the light-receiving element can be reduced, and detection accuracy can be improved.

[0047] The first potential is preferably as close as possible to the potential applied to the first pixel electrode. This reduces the potential difference between the first pixel electrode and the conductive layer, thereby sufficiently suppressing side leakage current flowing through the common layer between the first pixel electrode and the conductive layer. Furthermore, it is preferable to apply the same first potential to the common electrode as to the conductive layer. This allows a common circuit to apply a potential to the common electrode and a common circuit to apply a potential to the conductive layer, thereby simplifying the circuit configuration.

[0048] The conductive layer may be provided between the first pixel electrode and the second pixel electrode in a plan view. Specifically, the conductive layer can be provided on the shortest straight line connecting the first pixel electrode and the second pixel electrode. If the common layer, which causes side leakage current, is an ideally uniform film, the side leakage current tends to flow along the shortest straight line connecting the pixel electrodes. Therefore, by arranging the conductive layer in such a position, it is possible to effectively block side leakage current that may flow between the first pixel electrode and the second pixel electrode.

[0049] Preferably, the conductive layer has a ring-shaped portion, and the first pixel electrode is located inside the ring-shaped portion. Preferably, the conductive layer is electrically connected to wiring in the display area. With this configuration, the first pixel electrode is surrounded by the conductive layer, thereby blocking the current path from the second pixel electrode. Therefore, side leakage current can be effectively suppressed. Alternatively, the conductive layer may have a ring-shaped first portion, a ring-shaped second portion, and a third portion, with the third portion located between the first and second portions. In this case, one of the multiple first pixel electrodes may be located inside the first portion, and another may be located inside the second portion. Preferably, the conductive layer is provided across the display area or the display and non-display areas, and is electrically connected to wiring in the display area or the non-display area. With this configuration, the first pixel electrode is surrounded by the conductive layer, thereby effectively suppressing side leakage current, as described above. Furthermore, the wiring in the display area can be reduced, enabling pixel miniaturization.

[0050] The first pixel electrode located inside the annular conductive layer may be replaced with a second pixel electrode. This allows the second pixel electrode to be surrounded by the conductive layer, blocking the current path from the second pixel electrode. This effectively suppresses side leakage current.

[0051] In one embodiment of the present invention, a liquid crystal display device includes a plurality of first pixel electrodes and a plurality of second pixel electrodes, each of which is arranged in a first direction. The conductive layer preferably extends in the first direction and is provided between the plurality of first pixel electrodes and the plurality of second pixel electrodes. The conductive layer preferably is electrically connected to wiring in the display area or the non-display area. This configuration allows the plurality of first pixel electrodes and the plurality of second pixel electrodes to be separated by a single continuous conductive layer, simplifying the layout on the substrate.

[0052] The conductive layer is preferably made of a conductive material with high conductivity. The conductive layer and the pixel electrode can be made of the same material. The conductive layer, the first pixel electrode, and the second pixel electrode can be formed using the same film in the same process, thereby simplifying the manufacturing process. The conductive layer, the first pixel electrode, and the second pixel electrode are preferably made of a conductive material with high visible light reflectance and high conductivity, such as aluminum or silver. An alloy containing aluminum and one or more elements selected from titanium, neodymium, nickel, and lanthanum can also be used. Alternatively, an alloy containing silver and one or more elements selected from yttrium, magnesium, ytterbium, aluminum, titanium, gallium, zinc, indium, tungsten, manganese, tin, iron, nickel, copper, palladium, iridium, and gold can also be used.

[0053] The wiring is provided on a surface different from the conductive layer. Examples of conductive materials that can be used for the wiring include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys containing these metals as their main components. Furthermore, the wiring can be formed using a film containing these materials in a single layer or a multilayer structure.

[0054] The display device of one embodiment of the present invention will be described in more detail below with reference to the drawings.

[0055] [Display device configuration example 1] FIG. 1A is a schematic cross-sectional view of a display portion of a display device 10A according to one embodiment of the present invention.

[0056] The display device 10A includes a light receiving element 20, a light emitting element 30, a conductive layer 40, wiring 50, and the like.

[0057] The light receiving element 20, the light emitting element 30, and the conductive layer 40 are provided on the same surface between the substrate 11 and the substrate 12. The light receiving element 20, the light emitting element 30, and the conductive layer 40 are each located on the insulating layer 13. The wiring 50 is provided on the substrate 11, and is provided on a different surface from the light receiving element 20, the light emitting element 30, and the conductive layer 40. As shown in FIG. 1A, the wiring 50 is preferably provided below (on the substrate 11 side) the light receiving element 20, the light emitting element 30, and the conductive layer 40.

[0058] The light receiving element 20 has a function of receiving light 90 incident from the substrate 12 side and converting it into an electrical signal. The light receiving element 20 functions as a photoelectric conversion element.

[0059] The light-receiving element 20 has a structure in which a pixel electrode 41, a common layer 61, a light-receiving layer 21, and a common electrode 60 are stacked. A transistor 51 electrically connected to the pixel electrode 41 is preferably provided on the substrate 11. The pixel electrode 41 is electrically connected to the source or drain of the transistor 51 through an opening provided in the insulating layer 13. A common layer 62 is preferably provided between the light-receiving layer 21 and the common electrode 60. The common electrode 60 is preferably covered with a protective layer 63.

[0060] The light emitting element 30 has a function of emitting light 80 toward the substrate 12 side.

[0061] The light-emitting element 30 has a stacked structure of a pixel electrode 42, a common layer 61, a light-emitting layer 31, and a common electrode 60. A transistor 52 electrically connected to the pixel electrode 42 is preferably provided on the substrate 11. The pixel electrode 42 is electrically connected to the source or drain of the transistor 52 through an opening provided in the insulating layer 13. The common layer 62 is preferably provided between the light-emitting layer 31 and the common electrode 60. The common electrode 60 is preferably covered with a protective layer 63.

[0062] The light-emitting element 30 may be a light-emitting element that emits light of any one of red (R), green (G), or blue (B), or may be a light-emitting element that emits light of white (W), yellow (Y), or the like. The light-emitting element 30 may have two or more peaks in its emission spectrum.

[0063] The conductive layer 40 has a function of preventing side leakage current from flowing into the pixel electrode 41. The conductive layer 40 is electrically connected to the common layer 61. In addition, the common layer 61 and the common electrode 60 are stacked on the conductive layer 40. In addition, the conductive layer 40 is electrically connected to the wiring 50 in the display area or the non-display area, and a first potential is applied to the wiring 50. As described above, the wiring 50 is provided on the substrate 11, and is provided on a different surface from the light receiving element 20, the light emitting element 30, and the conductive layer 40.

[0064] The partition wall 14 has a function of electrically insulating (also referred to as electrically separating) the pixel electrode 41, the pixel electrode 42, and the conductive layer 40 from each other. Ends of the pixel electrode 41, the pixel electrode 42, and the conductive layer 40 are covered with the partition wall 14.

[0065] An organic insulating film is suitable for the partition wall 14. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. The partition wall 14 is a layer that transmits visible light. Instead of the partition wall 14, a partition wall that blocks visible light may be provided.

[0066] Here, the pixel electrode 41, the pixel electrode 42, and the conductive layer 40 are preferably formed by processing the same conductive film. The common layer 61 has portions that overlap with the pixel electrode 41, the pixel electrode 42, and the conductive layer 40, respectively. The common layer 62 and the common electrode 60 have portions that overlap with the pixel electrode 41 via the light-receiving layer 21 and the common layer 61, portions that overlap with the pixel electrode 42 via the light-emitting layer 31 and the common layer 61, and portions that overlap with the conductive layer 40 via the common layer 61. With this configuration, the light-receiving element 20 and the light-emitting element 30 can be manufactured using a common process except for the light-receiving layer 21 and the light-emitting layer 31, thereby reducing manufacturing costs.

[0067] 1B shows a cross-sectional view of the display unit of the display device 10B. In this way, the wiring 50 does not necessarily have to be provided in the display unit.

[0068] The wiring 50 is preferably formed using the same conductive film as the electrodes of the transistors 51 and 52. For example, the wiring 50 is preferably formed by processing the same conductive film as the gate electrodes, back gate electrodes, source electrodes, drain electrodes, or other electrodes or wirings of the transistors 51 and 52. This allows the wiring 50 to be formed without increasing the number of steps.

[0069] [Potential setting] As mentioned above, the difference in potential applied to the pixel electrodes 41 and 42 can cause side leakage current from the pixel electrode 42 to the pixel electrode 41 through the common layer 61. Figure 2A shows a schematic diagram of the relationship between the current density (J) and voltage (V) of the current flowing through the organic thin film. At voltages lower than a certain voltage A, an ohmic current proportional to the voltage (current that flows primarily according to Ohm's law) flows. However, above a certain voltage A, a current proportional to the square of the voltage flows according to Child's law. Because the organic thin film used in the common layer 61 has a low carrier density, the current flowing through the layer exhibits the voltage dependence shown in Figure 2A. Because the light-receiving element is negatively biased and the light-emitting element is positively biased, the potential difference between the pixel electrodes becomes very large, and Child's law may apply to the side leakage current flowing between the pixel electrodes through the common layer 61. In other words, a large amount of side leakage current can occur between the pixel electrodes 41 and 42.

[0070] Therefore, one embodiment of the present invention has a structure in which a conductive layer 40 is disposed between the pixel electrode 41 and the pixel electrode 42. By applying an appropriate potential to the conductive layer 40, a side leakage current generated between the pixel electrode 41 and the pixel electrode 42 can be made to flow to the conductive layer 40.

[0071] At this time, the potential of the conductive layer 40 is set so that the side leakage current occurring between the pixel electrode 41 and the conductive layer 40 is extremely small compared to the side leakage current that may occur between the pixel electrode 41 and the pixel electrode 42. As shown in FIG. 2A, by setting the potential difference between the pixel electrode 41 and the conductive layer 40 of the light-receiving element 20 to a range equal to or less than voltage A, the magnitude of the side leakage current between the pixel electrode 41 and the conductive layer 40 can be kept within the range of ohmic current. Therefore, the side leakage current can be effectively suppressed.

[0072] The voltage A can be estimated by measuring the current-voltage characteristics between the pixel electrode 41 and the conductive layer 40. For example, the voltage A is a value determined by the material of the common layer 61, the stacking configuration of the common layer 61, the thickness of the common layer 61, the distance between the two electrodes, and the like.

[0073] 2B is a schematic diagram showing an example of potentials applied to pixel electrode 41, pixel electrode 42, and conductive layer 40. In FIG. 2B, the vertical axis indicates potential (V), and the vertical arrows indicate the range of potentials that each pixel electrode or conductive layer 40 can take.

[0074] A potential 100 is applied to the common electrode 60. Furthermore, potential 101 is a potential that can be applied to the conductive layer 40 and can take values ​​ranging from potential 101L to potential 101H. Potential 102 is a potential that can be applied to the pixel electrode 41 of the light-receiving element 20 and can take values ​​ranging from potential 102L to potential 102H. Potential 103 is a potential that can be applied to the pixel electrode 42 of the light-emitting element 30 and can take values ​​ranging from potential 103L to potential 103H.

[0075] Since the light-receiving element 20 is reverse-bias driven, when the common electrode 60 is the cathode, the potential 102H is set to a potential of 100 or less. Since the light-emitting element 30 is forward-bias driven, the potential 103L is set to a potential of 100 or more. Furthermore, in order to suppress side leakage current from the pixel electrode 42 to the pixel electrode 41, the potential 101H is set to a potential of 103H or less. With this configuration, the side leakage current flowing from the conductive layer 40 to the pixel electrode 41 is smaller than the side leakage current flowing from the pixel electrode 42 to the pixel electrode 41 when the conductive layer 40 is not provided. In other words, the side leakage current flowing from the pixel electrode 42 to the pixel electrode 41 can be blocked by the conductive layer 40.

[0076] Furthermore, it is preferable that the potential 101 applied to the conductive layer 40 is the same as the potential 100. By applying the same potential to the common electrode 60 and the conductive layer 40, the number of circuits required to generate the potential can be reduced. It is also more preferable that the potential 101 applied to the conductive layer 40 be set within a range of potential 102 plus or minus A, with potential 102 as the reference. Within this range, the side leakage current flowing to the first pixel electrode can be kept within the ohmic current range. This effectively reduces noise in the light-receiving element, enabling clear imaging.

[0077] [Pixel electrode and conductive layer arrangement] As described above, one embodiment of the present invention can capture an image using a plurality of light-receiving elements. Furthermore, an image can be displayed using a plurality of light-emitting elements. A full-color display device can be realized by arranging light-emitting elements of three colors, for example, red (R), green (G), and blue (B), in one pixel of the display device. An example of a method for arranging pixel electrodes and conductive layers of a display device will be described below.

[0078] 3A to 8A, 9A and 9B, and 12 to 13B show examples of planar layouts of pixel electrodes 41, 42, conductive layer 40, etc. Pixel electrode 41 is a pixel electrode of a light receiving element, pixel electrode 42R is a pixel electrode of a red light emitting element, pixel electrode 42G is a pixel electrode of a green light emitting element, and pixel electrode 42B is a pixel electrode of a blue light emitting element. Note that hereinafter, when there is no need to distinguish between pixel electrodes 42R, 42G, and 42B, they may be referred to as pixel electrode 42.

[0079] The configuration examples shown in FIGS. 3A to 4C are examples in which three light-emitting elements and one light-receiving element are arranged in a row.

[0080] FIG. 3A shows a display device 110A. In a plan view, the display device 110A has a pixel electrode 41 located inside a ring-shaped conductive layer 40. The display device 110A also has wiring 50 below the pixel electrodes 41 and 42. The conductive layer 40 is electrically connected to the wiring 50 via a connection portion 55 that overlaps the conductive layer 40. A potential 101 is applied to the conductive layer 40 via the wiring 50. With this configuration, the pixel electrode 41 is separated from the pixel electrode 42 by the conductive layer 40, and the conductive layer 40 effectively blocks side leakage current flowing from the pixel electrode 42 to the pixel electrode 41. This reduces noise in the light-receiving element, enabling clearer imaging. Furthermore, because the wiring 50 overlaps the pixel electrodes 41 and 42, the display space can be effectively utilized. This allows for finer pixel size and a higher aperture ratio for the pixel electrodes.

[0081] 3B differs from the display device 110A mainly in that the wiring 50 does not overlap the pixel electrodes 41 and 42. This reduces the parasitic capacitance between the wiring 50 and each pixel electrode, thereby enabling high-speed driving.

[0082] 3C is different from the display device 110A mainly in that the display device 110C has a rod-shaped (also called strip-shaped) conductive layer 40. The conductive layer 40 is located between the pixel electrode 41 and the pixel electrode 42. The shape of the rod-shaped conductive layer 40 may be linear or curved.

[0083] Furthermore, as in a display device 110D shown in FIG. 3D, the wiring 50 may be configured not to overlap the pixel electrodes 41 and .

[0084] 4A differs from the display device 110A mainly in that pixel electrodes 42R, 42G, and 42B are located inside the annular conductive layer 40. Even in this configuration in which the pixel electrode 42 of the light-emitting element is surrounded by the conductive layer 40, the pixel electrode 41 is separated from the pixel electrode 42 by the conductive layer 40, so that side leakage current flowing from the pixel electrode 42 to the pixel electrode 41 can be effectively blocked. This reduces noise in the light-receiving element, enabling clearer imaging.

[0085] Furthermore, although FIG. 4A shows an example in which the wiring 50 overlaps the pixel electrode 41 and the pixel electrode 42, they may be configured not to overlap, as in a display device 110F shown in FIG. 4B.

[0086] Although the above example shows that the wiring 50 is disposed in the display section, the wiring 50 can also be disposed in an area outside the display section (non-display section). The dashed-dotted line shown in Fig. 4C indicates the boundary between the display section 120 and the non-display section 121 of the display device 110G. The pixel electrodes 41 and 42 are located in the display section 120.

[0087] 4C shows a display device 110G in which three light-emitting elements and one light-receiving element are arranged in a row, repeatedly arranged in the vertical direction. Furthermore, the conductive layer 40 is electrically connected to the wiring 50 via a connection portion 55 located in the non-display portion 121. Furthermore, the conductive layer 40 is located between adjacent pixel electrodes 41 and 42, and is provided across the display portion 120 and the non-display portion 121. Furthermore, the wiring 50 is provided in the non-display portion 121 without overlapping the pixel electrodes 41 and 42.

[0088] In the display device 110G, pixel electrodes 41 and 42 are separated by conductive layer 40, enabling clear imaging. Furthermore, since wiring 50 is arranged in non-display area 121, the pixels of display area 120 can be miniaturized, allowing for higher-resolution images to be displayed. Furthermore, since connection portions 55 for multiple conductive layers 40 can be provided on one wiring 50, the circuit can be simplified.

[0089] Although not shown here, non-display section 121 is preferably provided so as to surround display section 120. Furthermore, it is preferable that wiring 50 is provided in each of a pair of sections of non-display section 121 that sandwich display section 120. In this case, FIG. 4C corresponds to one of the pair of sections of non-display section 121. Furthermore, in this case, the other of the pair of sections can have a configuration in which FIG. 4C is upside down.

[0090] The configuration examples shown in FIGS. 5A to 6C are examples in which three light-emitting elements are arranged in a row, and one horizontally long light-receiving element is arranged below them.

[0091] 5A shows a display device 110H. Similar to the display device 110A, the pixel electrodes 41 of the display device 110H are located inside the annular conductive layer 40. Alternatively, the wiring 50 may not overlap the pixel electrodes 41, as in the display device 110J shown in FIG. 5B.

[0092] 6A shows a display device 110K. Similar to the display device 110E, the pixel electrodes 42R, 42G, and 42B of the display device 110K are located inside the annular conductive layer 49. Also, as in the display device 110L shown in FIG. 6B, the wiring 50 may not overlap the pixel electrodes 42.

[0093] Display device 110M shown in FIG. 6C differs from display device 110G mainly in that it has three light-emitting elements arranged in a row and one horizontally elongated light-receiving element arranged below them.

[0094] The configuration example shown in FIGS. 7A and 7B is an example in which green light-emitting elements, red light-emitting elements, and light-receiving elements are arranged in a vertical line, and a vertically elongated blue light-emitting element is arranged to the side thereof.

[0095] 7A shows a display device 110N. The pixel electrodes 41 of the display device 110N are located inside the annular conductive layer 40, similar to the display device 110A.

[0096] Figure 7B shows display device 110P. The dashed dotted line shown in Figure 7B indicates the boundary between display section 120 and non-display section 121 of display device 110P.

[0097] In comparison with the display device 110N, the display device 110P has the conductive layer 40 electrically connected to the wiring 50 via a connection portion 55 that overlaps with the conductive layer 40 in the non-display portion 121. Furthermore, the conductive layer 40 has an annular first portion 40a and a second portion 40b, and is provided across the display portion 120 and the non-display portion 121. The main difference is that the wiring 50 is located in the non-display portion 121.

[0098] The first portion 40a has a ring-shaped portion, inside which the pixel electrode 41 is located. The second portion 40b is located between the pair of first portions 40a and connects them. Furthermore, the conductive layer 40 is provided across the display portion 120 and the non-display portion 121, and is electrically connected to the wiring 50 via a connection portion 55 that overlaps with the conductive layer 40 in the non-display portion 121.

[0099] With this configuration, pixel electrode 41 is separated from pixel electrode 42 by conductive layer 40, enabling clear imaging. Furthermore, since wiring 50 is arranged in the non-display area, the pixels in the display area can be miniaturized, allowing for higher-resolution images to be displayed. Furthermore, since connection portions 55 for multiple conductive layers 40 can be provided on one wiring 50, the circuit can be simplified, which is preferable.

[0100] 8A, 9, 12, and 13 show examples in which three light-emitting elements and one light-receiving element are repeatedly arranged in a matrix. The dashed-dotted lines in the figures indicate the boundary between the display area 120 and the non-display area 121 of each display device.

[0101] 8A shows a display device 110Q. The pixel electrodes 41 of the display device 110Q are located inside the annular conductive layer 40, similar to the display device 110A.

[0102] FIG. 8B corresponds to a cross-sectional view taken along the two-dot chain line AB shown in FIG. 8A.

[0103] In the above cross-sectional view, the wiring 50 is located between the substrate 11, the pixel electrode 41, and the conductive layer 40. The wiring 50 is provided on the substrate 11 from one non-display section 121 through the display section 120 to the other non-display section 121, and has portions that overlap with the pixel electrode 41, the conductive layer 40, and the light-receiving layer 21. The conductive layer 40 is electrically connected to the wiring 50 via a connection section 55. The transistors connected to the pixel electrode 41 and the pixel electrode 42, respectively, and the wiring 50 are located on the same plane, but are arranged so as not to interfere with each other.

[0104] The display device 110R shown in FIG. 9A differs from the display device 110Q shown in FIG. 8A mainly in that the conductive layer 40 has a first portion 40a and a second portion 40b.

[0105] The first portion 40a has a ring-shaped portion, and the pixel electrode 41 is located inside the ring-shaped portion. The second portion 40b is located between the pair of first portions 40a and connects them. With this configuration, the number of wirings 50 in the display unit 120 can be reduced by more than half compared to when the first portions 40a are not connected by the second portions 40b, allowing for more effective use of the space in the display unit. This makes it possible to miniaturize pixels or increase the aperture ratio of pixel electrodes.

[0106] 9B shows a display device 110S. The pixel electrode 41 of the display device 110S is located inside the annular first portion 40a of the conductive layer 40, similar to the display device 110P.

[0107] Figures 10A and 10B correspond to cross-sectional views taken along the two-dot chain line CD in Figure 9A. In the cross-sectional views of Figures 10A and 10B, the second portion 40b is located between a pair of first portions 40a.

[0108] 10A shows an example in which the partition wall 14 is not provided on the second portion 40b of the conductive layer 40, and FIG. 10B shows an example in which the partition wall 14 is provided on the second portion 40b. As shown in FIG. 10B, the partition wall 14 may be configured to cover not only the end portion of the first portion 40a but also a part of the upper portion of the second portion 40b. In other words, the first portion 40a or the second portion 40b may be electrically connected to the common layer 61 at two or more locations.

[0109] 11A and 11B correspond to cross-sectional views taken along the dashed two-dot line EF in Fig. 9B. The cross-sectional view of Fig. 11A differs from Fig. 10A, and the cross-sectional view of Fig. 11B differs from Fig. 10B mainly in that wiring 50 is not provided in display unit 120.

[0110] The display device 110T shown in FIG. 12 differs from the display device 110S mainly in that the pixel electrode 42G is located inside the annular first portion 40a.

[0111] The light-emitting elements provided in the display unit 120 can be used as light sources during imaging. When a green light-emitting element is used as the light source, side leakage current may occur from the pixel electrode 42G to the pixel electrode 41. Therefore, as in the display device 110T, the pixel electrode 42G may be located inside the annular first portion 40a. By surrounding the pixel electrode 42G with the conductive layer 40, the above-mentioned side leakage current can be suppressed. Furthermore, when a red light-emitting element is used as the light source, the pixel electrode 42R may be located inside the first portion 40a. Similarly, when a blue light-emitting element is used as the light source, the pixel electrode 42B may be located inside the first portion 40a.

[0112] The display device 110U shown in FIG. 13A is an example in which the shape of the second portion 40b of the display device 110S is modified. The second portion 40b is provided so as not to contact the pixel electrode 41 or the pixel electrode 42. For example, the second portion 40b may have a shape with one or more inflection points, as in the display device 110U. For example, the second portion 40b may have a part of its top surface shape that is V-shaped, L-shaped, or U-shaped.

[0113] The display device 110W shown in FIG. 13B is a configuration example that combines the arrangements of the display devices 110Q and 110S. In the display device 110W, a pixel electrode 41 is located inside an annular conductive layer 40X. Furthermore, the conductive layer 40Y has a first portion 40a and a second portion 40b. The first portion 40a has an annular portion, and the pixel electrode 41 is located inside the annular portion. Furthermore, the second portion 40b is located between the pair of first portions 40a.

[0114] Furthermore, the conductive layer 40X is electrically connected to the wiring 50X via a connection portion 55a located in the display portion 120. The conductive layer 40Y is electrically connected to the wiring 50 via a connection portion 55b located in the non-display portion 121. Furthermore, a potential 101 is applied to the conductive layer 40X via the wiring 50X, and to the conductive layer 40Y via the wiring 50Y. With this configuration, the pixel electrode 41 is separated from the pixel electrode 42 by the conductive layer 40, and therefore the conductive layer 40 can block side leakage current from the pixel electrode 42 to the pixel electrode 41.

[0115] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0116] (Embodiment 2) In this embodiment, a more specific structural example of a display device according to one embodiment of the present invention will be described. Note that the following description partially overlaps with Embodiment 1.

[0117] A display portion of a display device according to one embodiment of the present invention includes a light-receiving element and a light-emitting element. The display portion has a function of displaying an image using the light-emitting element. Furthermore, the display portion has one or both of an imaging function and a sensing function using the light-receiving element.

[0118] Alternatively, the display device of one embodiment of the present invention may have a structure including a light-emitting and light-emitting element (also referred to as a light-emitting and light-receiving device) and a light-emitting element.

[0119] The first embodiment can be applied to the outline of the display device having a light receiving element and a light emitting element.

[0120] For example, when the light receiving element is used as an image sensor, the display device can capture an image using the light receiving element, and can be used as, for example, a scanner.

[0121] An electronic device to which the display device of one embodiment of the present invention is applied can acquire data related to biometric information such as a fingerprint or palm print by using a function as an image sensor. That is, a biometric authentication sensor can be built into the display device. The built-in biometric authentication sensor in the display device reduces the number of components in the electronic device compared to a case in which a biometric authentication sensor is provided separately from the display device, and the electronic device can be made smaller and lighter.

[0122] Furthermore, when the light receiving element is used as a touch sensor, the display device can detect a touch operation of an object using the light receiving element.

[0123] In one embodiment of the present invention, an organic EL element (also referred to as an organic EL device) is used as a light-emitting element, and an organic photodiode is used as a light-receiving element. The organic EL element 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 element.

[0124] If all the layers constituting the organic EL element and the organic photodiode were to be fabricated separately, the number of film formation processes would be enormous. However, since the organic photodiode has many layers that can be configured in common with the organic EL element, the layers that can be configured in common can be formed in one go, thereby suppressing the increase in film formation processes.

[0125] For example, one of the pair of electrodes (common electrode) can be a layer common to the light-receiving element and the light-emitting element. It is also preferable that at least one of the hole injection layer, hole transport layer, electron transport layer, and electron injection layer be a layer common to the light-receiving element and the light-emitting element. Furthermore, the light-receiving element and the light-emitting element can have the same configuration, except that the light-receiving element has an active layer and the light-emitting element has an emitting layer. That is, a light-receiving element can be fabricated simply by replacing the emitting layer of the light-emitting element with an active layer. By having a common layer between the light-receiving element and the light-emitting element, the number of film formations and the number of masks can be reduced, thereby reducing the manufacturing process and manufacturing costs of the display device. Furthermore, a display device having a light-receiving element can be fabricated using existing display device manufacturing equipment and manufacturing methods.

[0126] Note that a layer common to a light-receiving element and a light-emitting element may have different functions in the light-emitting element and the light-receiving element. In this specification, components are named based on their functions in the light-emitting element. For example, a hole injection layer functions as a hole injection layer in the light-emitting element and functions as a hole transport layer in the light-receiving element. Similarly, an electron injection layer functions as an electron injection layer in the light-emitting element and functions as an electron transport layer in the light-receiving element. Furthermore, a layer common to a light-receiving element and a light-emitting element may have the same function in the light-emitting element and the light-receiving element. A hole transport layer functions as a hole transport layer in both the light-emitting element and the light-receiving element, and an electron transport layer functions as an electron transport layer in both the light-emitting element and the light-receiving element.

[0127] Next, a display device having light emitting and receiving elements and a light emitting element will be described. Note that the description of the same functions, actions, effects, etc. as those described above may be omitted.

[0128] In a display device according to one embodiment of the present invention, a subpixel that exhibits one of the colors has a light-receiving and light-emitting element instead of a light-emitting element, and a subpixel that exhibits the other color has a light-emitting element. The light-receiving and light-emitting element has both a function of emitting light (light-emitting function) and a function of receiving light (light-receiving function). For example, when a pixel has three subpixels, namely, a red subpixel, a green subpixel, and a blue subpixel, at least one subpixel has a light-receiving and light-emitting element, and the other subpixels have light-emitting elements. Therefore, the display portion of the display device according to one embodiment of the present invention has a function of displaying an image using both the light-receiving and light-emitting elements and the light-emitting elements.

[0129] By using a light-receiving / light-emitting element that serves as both a light-emitting element and a light-receiving element, a pixel can be given a light-receiving function without increasing the number of subpixels included in the pixel. This allows one or both of an imaging function and a sensing function to be added to the display portion of the display device while maintaining the aperture ratio of the pixel (aperture ratio of each subpixel) and the resolution of the display device. Therefore, the display device of one embodiment of the present invention can have a higher aperture ratio of the pixel and can easily achieve higher resolution than a display device in which a subpixel having a light-receiving element is provided separately from a subpixel having a light-emitting element.

[0130] In a display device according to one embodiment of the present invention, light-emitting and light-emitting elements are arranged in a matrix in a display portion, and an image can be displayed on the display portion. The display portion can also be used as an image sensor, a touch sensor, or the like. In the display device according to one embodiment of the present invention, the light-emitting elements can be used as a light source for the sensor. Therefore, imaging and detection of touch operations are possible even in a dark place.

[0131] Light-emitting and receiving elements can be fabricated by combining an organic EL element and an organic photodiode. For example, light-emitting and receiving elements can be fabricated by adding the active layer of an organic photodiode to the layered structure of an organic EL element. Furthermore, light-emitting and receiving elements fabricated by combining an organic EL element and an organic photodiode can suppress an increase in the number of film-forming steps by forming layers that can be configured in common with the organic EL element in a single step.

[0132] For example, one of the pair of electrodes (common electrode) can be a layer common to the light-emitting and receiving elements and the light-emitting element. It is also preferable that at least one of the hole injection layer, hole transport layer, electron transport layer, and electron injection layer be a layer common to the light-emitting and receiving elements and the light-emitting element. Furthermore, the light-emitting and receiving elements and the light-emitting element can have the same configuration, except for the presence or absence of an active layer of the light-receiving element. In other words, the light-emitting and receiving elements can be fabricated simply by adding the active layer of the light-receiving element to the light-emitting element. Having a common layer between the light-emitting and receiving elements and the light-emitting element in this way can reduce the number of film formations and masks, thereby reducing the manufacturing process and manufacturing costs of the display device. Furthermore, a display device having a light-emitting and receiving element can be fabricated using existing display device manufacturing equipment and manufacturing methods.

[0133] Note that the layers of the light emitting / receiving element may have different functions depending on whether the light emitting / receiving element functions as a light receiving element or a light emitting element. In this specification, the components are referred to based on their functions when the light emitting / receiving element functions as a light emitting element.

[0134] The display device of this embodiment mode has a function of displaying an image using a light-emitting element and a light-emitting / light-emitting element. That is, the light-emitting element and the light-emitting / light-emitting element function as display elements.

[0135] The display device of this embodiment has a function of detecting light using a light receiving and emitting element, which can detect light having a shorter wavelength than light emitted by the light receiving and emitting element itself.

[0136] When the light-emitting / receiving elements are used as an image sensor, the display device of this embodiment can capture an image using the light-emitting / receiving elements. When the light-emitting / receiving elements are used as a touch sensor, the display device of this embodiment can detect a touch operation of an object using the light-emitting / receiving elements.

[0137] The light-receiving / light-emitting element functions as a photoelectric conversion element. The light-receiving / light-emitting element can be fabricated by adding an active layer of a light-receiving element to the configuration of the light-emitting element. For example, the active layer of a pn-type or pin-type photodiode can be used for the light-receiving / light-emitting element.

[0138] In particular, it is preferable to use an organic photodiode active layer having a layer containing an organic compound as the light-receiving / light-emitting element. 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.

[0139] Here, a side leakage current may occur between the light-receiving and light-emitting elements through the common layer. Therefore, a conductive layer electrically connected to the common layer is provided between the light-receiving and light-emitting elements and the light-emitting element in a plan view. The arrangement and shape of the conductive layer may be the same as in the case of using a light-receiving element, and various structures exemplified in the above embodiment 1 may be applied.

[0140] The display device of one embodiment of the present invention will be described in more detail below with reference to the drawings.

[0141] [Display device configuration example 1] [Configuration Example 1-1] 14A is a schematic diagram of a display panel 200. The display panel 200 includes a substrate 201, a substrate 202, a light receiving element 212, a light emitting element 211R, a light emitting element 211G, a light emitting element 211B, a functional layer 203, and the like.

[0142] The light-emitting element 211R, the light-emitting element 211G, the light-emitting element 211B, and the light-receiving element 212 are provided between the substrate 201 and the substrate 202. The light-emitting element 211R, the light-emitting element 211G, and the light-emitting element 211B emit red (R), green (G), or blue (B) light, respectively. Note that hereinafter, when there is no need to distinguish between the light-emitting element 211R, the light-emitting element 211G, and the light-emitting element 211B, they may be referred to as the light-emitting element 211.

[0143] The display panel 200 has a plurality of pixels arranged in a matrix. Each pixel has one or more sub-pixels. Each sub-pixel has one light-emitting element. For example, a pixel may have three sub-pixels (e.g., three colors of R, G, and B, or three colors of yellow (Y), cyan (C), and magenta (M)), or four sub-pixels (e.g., four colors of R, G, B, and white (W), or four colors of R, G, B, and Y). Each pixel also has a light-receiving element 212. The light-receiving element 212 may be provided in all pixels or in some of the pixels. Alternatively, one pixel may have multiple light-receiving elements 212.

[0144] 14A shows a state in which finger 220 is approaching the surface of substrate 202. A part of the light emitted by light emitting element 211G is reflected by finger 220. Then, a part of the reflected light is incident on light receiving element 212, and it is possible to detect that finger 220 is approaching above substrate 202. In other words, display panel 200 can function as a non-contact type touch panel. Note that, since it can detect even when finger 220 touches substrate 202, display panel 200 can also function as a contact type touch panel (also simply referred to as a touch panel).

[0145] The functional layer 203 has a circuit for driving the light-emitting element 211R, the light-emitting element 211G, and the light-emitting element 211B, and a circuit for driving the light-receiving element 212. The functional layer 203 is provided with switches, transistors, capacitors, wiring, and the like. Note that when the light-emitting element 211R, the light-emitting element 211G, the light-emitting element 211B, and the light-receiving element 212 are driven by a passive matrix method, a configuration may be adopted in which switches, transistors, and the like are not provided.

[0146] It is preferable that the display panel 200 has a function of capturing an image of a fingerprint of a finger 220. Fig. 14B is a schematic enlarged view of a contact portion when the finger 220 is in contact with the substrate 202. Fig. 14B also shows light emitting elements 211 and light receiving elements 212 arranged alternately.

[0147] A fingerprint is formed by concave and convex portions of finger 220. Therefore, the convex portions of the fingerprint are in contact with substrate 202 as shown in FIG.

[0148] Light reflected from a surface or interface can be classified as specular or diffuse. Specular reflected light is highly directional, with the angle of incidence and the angle of reflection matching, while diffuse reflected light is less directional, with its intensity less dependent on the angle. The diffuse reflection component is dominant in the light reflected from the surface of the finger 220. On the other hand, the specular reflection component is dominant in the light reflected from the interface between the substrate 202 and the atmosphere.

[0149] The intensity of light reflected by the contact or non-contact surface between finger 220 and substrate 202 and incident on light receiving element 212 located directly below them is the sum of specularly reflected light and diffusely reflected light. As described above, at the concave portions of finger 220, substrate 202 and finger 220 do not come into contact, so specularly reflected light (indicated by solid arrows) is dominant, whereas at the convex portions, they come into contact, so diffusely reflected light (indicated by dashed arrows) from finger 220 is dominant. Therefore, the intensity of light received by light receiving element 212 located directly below the concave portions is higher than that of light receiving element 212 located directly below the convex portions. This makes it possible to capture an image of the fingerprint of finger 220.

[0150] A clear fingerprint image can be obtained by arranging the light receiving elements 212 at an interval smaller than the distance between two convex portions of a fingerprint, preferably the distance between adjacent concave and convex portions. Since the distance between concave and convex portions of a human fingerprint is approximately 200 μm, for example, the interval between the light receiving elements 212 is 400 μm or less, preferably 200 μm or less, more preferably 150 μm or less, even more preferably 100 μm or less, and even more preferably 50 μm or less, and is 1 μm or more, preferably 10 μm or more, and more preferably 20 μm or more.

[0151] Fig. 14C shows an example of a fingerprint image captured by display panel 200. In Fig. 14C, the outline of finger 220 is indicated by a dashed line and the outline of contact area 221 is indicated by a dashed line within imaging range 223. Within contact area 221, a fingerprint 222 with high contrast can be captured due to differences in the amount of light incident on light receiving element 212.

[0152] Even when the finger 220 and the substrate 202 are not in contact with each other, the fingerprint can be imaged by capturing an image of the uneven shape of the fingerprint of the finger 220.

[0153] The display panel 200 can also function as a touch panel or a pen tablet, etc. Fig. 14D shows a state in which the tip of a stylus 225 is brought close to the substrate 202 and slid in the direction of the dashed arrow.

[0154] As shown in FIG. 14D, the diffused reflected light diffused by the tip of the stylus 225 is incident on the light receiving element 212 located at the part overlapping with the tip, thereby enabling the position of the tip of the stylus 225 to be detected with high accuracy.

[0155] 14E shows an example of a trajectory 226 of the stylus 225 detected by the display panel 200. The display panel 200 is capable of detecting the position of a detectable object such as the stylus 225 with high positional accuracy, and therefore is also capable of performing high-resolution drawing in drawing applications and the like. Furthermore, unlike when a capacitance-type touch sensor or an electromagnetic induction-type touch pen is used, the position of even a highly insulating detectable object can be detected, and therefore the material of the tip of the stylus 225 is not a factor, and various writing implements (for example, a brush, a glass pen, a feather pen, etc.) can be used.

[0156] 14F to 14H show an example of a pixel that can be applied to the display panel 200. FIG.

[0157] 14F and 14G each have a red (R) light-emitting element 211R, a green (G) light-emitting element 211G, a blue (B) light-emitting element 211B, and a light-receiving element 212. The pixel has a pixel circuit for driving the light-emitting element 211R, the light-emitting element 211G, the light-emitting element 211B, and the light-receiving element 212, respectively.

[0158] Fig. 14F shows an example in which three light-emitting elements and one light-receiving element are arranged in a 2 x 2 matrix. Fig. 14G shows an example in which three light-emitting elements are arranged in a row, and one horizontally elongated light-receiving element 212 is arranged below them.

[0159] 14H is an example of a pixel having a white (W) light-emitting element 211W. Here, four light-emitting elements are arranged in a row, and a light-receiving element 212 is arranged below them.

[0160] The pixel configuration is not limited to the above, and various arrangement methods can be adopted.

[0161] [Configuration Example 1-2] In the following, an example of a configuration including a light-emitting element that emits visible light, a light-emitting element that emits infrared light, and a light-receiving element will be described.

[0162] The display panel 200A shown in Fig. 15A includes a light-emitting element 211IR in addition to the configuration illustrated in Fig. 14A. The light-emitting element 211IR is a light-emitting element that emits infrared light IR. In this case, it is preferable to use an element that can receive at least the infrared light IR emitted by the light-emitting element 211IR as the light-receiving element 212. It is more preferable to use an element that can receive both visible light and infrared light as the light-receiving element 212.

[0163] As shown in FIG. 15A, when a finger 220 approaches the substrate 202, infrared light IR emitted from the light-emitting element 211IR is reflected by the finger 220, and a portion of the reflected light is incident on the light-receiving element 212, thereby obtaining position information of the finger 220.

[0164] 15B to 15D show examples of pixels applicable to the display panel 200A.

[0165] Fig. 15B shows an example in which three light-emitting elements are arranged in a row, and below them, light-emitting element 211IR and light-receiving element 212 are arranged side by side. Fig. 15C shows an example in which four light-emitting elements including light-emitting element 211IR are arranged in a row, and below them, light-receiving element 212 is arranged.

[0166] FIG. 15D shows an example in which three light emitting elements and a light receiving element 212 are arranged on all four sides with a light emitting element 211IR at the center.

[0167] In the pixels shown in FIGS. 15B to 15D, the positions of the light-emitting elements and the light-emitting elements and the light-receiving elements can be interchanged.

[0168] [Configuration Example 1-3] In the following, an example of a configuration including a light-emitting element that emits visible light and a light-receiving / light-emitting element that emits visible light and receives visible light will be described.

[0169] The display panel 200B shown in FIG. 16A includes a light-emitting element 211B, a light-emitting element 211G, and a light-receiving / light-emitting element 213R. The light-receiving / light-emitting element 213R functions as a light-emitting element that emits red (R) light and as a photoelectric conversion element that receives visible light. FIG. 16A shows an example in which the light-receiving / light-emitting element 213R receives green (G) light emitted by the light-emitting element 211G. The light-receiving / light-emitting element 213R may also receive blue (B) light emitted by the light-emitting element 211B. The light-receiving / light-emitting element 213R may also receive both green light and blue light.

[0170] For example, it is preferable that the light receiving / emitting element 213R receives light with a shorter wavelength than the light it emits. Alternatively, the light receiving / emitting element 213R may be configured to receive light with a longer wavelength than the light it emits (for example, infrared light). The light receiving / emitting element 213R may be configured to receive light with a wavelength similar to the light it emits, but in that case, it may also receive the light it emits, which could reduce the light emission efficiency. Therefore, it is preferable that the light receiving / emitting element 213R is configured so that the peak of the emission spectrum and the peak of the absorption spectrum do not overlap as much as possible.

[0171] In addition, the light emitted by the light emitting / receiving element is not limited to red light. Furthermore, the light emitted by the light emitting element is not limited to a combination of green light and blue light. For example, the light emitting / receiving element may be an element that emits green or blue light and receives light of a wavelength different from the light it emits.

[0172] In this way, by having the light emitting / receiving element 213R function as both a light emitting element and a light receiving element, the number of elements arranged in one pixel can be reduced, which makes it easier to achieve higher definition, a higher aperture ratio, and higher resolution.

[0173] 16B to 16I show an example of a pixel that can be applied to the display panel 200B.

[0174] Fig. 16B shows an example in which the light emitting / receiving element 213R, the light emitting element 211G, and the light emitting element 211B are arranged in a row. Fig. 16C shows an example in which the light emitting element 211G and the light emitting element 211B are arranged alternately in the vertical direction, and the light emitting / receiving element 213R is arranged next to them.

[0175] FIG. 16D shows an example in which three light-emitting elements (light-emitting element 211G, light-emitting element 211B, and light-emitting element 211X) and one light-receiving / light-emitting element are arranged in a 2×2 matrix. Light-emitting element 211X is an element that emits light other than R, G, and B. Examples of light other than R, G, and B include white (W), yellow (Y), cyan (C), magenta (M), infrared light (IR), and ultraviolet light (UV). When light-emitting element 211X emits infrared light, it is preferable that the light-receiving / light-emitting element has a function of detecting infrared light or a function of detecting both visible light and infrared light. The wavelength of light detected by the light-receiving / light-emitting element can be determined depending on the application of the sensor.

[0176] FIG. 16E shows two pixels. An area including three elements surrounded by dotted lines corresponds to one pixel. Each pixel has a light-emitting element 211G, a light-emitting element 211B, and an optical element 213R. In the left pixel shown in FIG. 16E, the light-emitting element 211G is arranged in the same row as the optical element 213R, and the light-emitting element 211B is arranged in the same column as the optical element 213R. In the right pixel shown in FIG. 16E, the light-emitting element 211G is arranged in the same row as the optical element 213R, and the light-emitting element 211B is arranged in the same column as the optical element 211G. In the pixel layout shown in FIG. 16E, the optical element 213R, the light-emitting element 211G, and the light-emitting element 211B are arranged repeatedly in both odd-numbered and even-numbered rows, and in each column, light-emitting elements or optical elements of different colors are arranged in the odd-numbered and even-numbered rows.

[0177] Figure 16F shows four pixels in a Pentile arrangement, with adjacent pixels each having a light-emitting or light-receiving element that emits two different colors of light. Figure 16F also shows the top view of the light-emitting or light-receiving element.

[0178] The upper left pixel and lower right pixel shown in Fig. 16F have a light emitting / receiving element 213R and a light emitting element 211G. The upper right pixel and lower left pixel have a light emitting element 211G and a light emitting element 211B. That is, in the example shown in Fig. 16F, a light emitting element 211G is provided in each pixel.

[0179] The top surface shapes of the light-emitting element and light-receiving / light-emitting element are not particularly limited and may be circular, elliptical, polygonal, polygonal with rounded corners, etc. Figure 16F etc. shows an example in which the top surface shapes of the light-emitting element and light-receiving / light-emitting element are squares (diamonds) tilted at approximately 45 degrees. Note that the top surface shapes of the light-emitting element and light-receiving / light-emitting element for each color may be different from each other, or may be the same for some or all of the colors.

[0180] Furthermore, the sizes of the light-emitting regions (or light-receiving and light-emitting regions) of the light-emitting elements and light-receiving and light-emitting elements of each color may be different from each other, or may be the same for some or all colors. For example, in FIG. 16F, the area of ​​the light-emitting region of the light-emitting element 211G provided in each pixel may be smaller than the light-emitting regions (or light-receiving and light-emitting regions) of the other elements.

[0181] Fig. 16G is a modified example of the pixel array shown in Fig. 16F. Specifically, the configuration in Fig. 16G is obtained by rotating the configuration in Fig. 16F by 45 degrees. Although Fig. 16F has been described as having two elements per pixel, it can also be understood that one pixel is made up of four elements, as shown in Fig. 16G.

[0182] Fig. 16H is a modified example of the pixel array shown in Fig. 16F. The upper left pixel and lower right pixel shown in Fig. 16H have light emitting / receiving elements 213R and light emitting elements 211G. The upper right pixel and lower left pixel have light emitting / receiving elements 213R and light emitting elements 211B. That is, in the example shown in Fig. 16H, each pixel is provided with a light emitting / receiving element 213R. Because each pixel is provided with a light emitting / receiving element 213R, the configuration shown in Fig. 16H can capture images with higher resolution than the configuration shown in Fig. 16F. This can improve the accuracy of biometric authentication, for example.

[0183] FIG. 16I is a modified example of the pixel array shown in FIG. 16H, and is obtained by rotating the pixel array by 45 degrees.

[0184] In FIG. 16I, a description will be given assuming that one pixel is composed of four elements (two light-emitting elements and two light-receiving and light-emitting elements). In this way, one pixel has multiple light-receiving and light-emitting elements with a light-receiving function, allowing for imaging with high resolution. This can improve the accuracy of biometric authentication. For example, the resolution of imaging can be set to the root double of the resolution of display.

[0185] A display device to which the configuration shown in Figure 16H or Figure 16I is applied has p (p is an integer of 2 or more) first light-emitting elements, q (q is an integer of 2 or more) second light-emitting elements, and r (r is an integer greater than p and greater than q) light-receiving and light-emitting elements. p and r satisfy r = 2p. Furthermore, p, q, and r satisfy r = p + q. One of the first light-emitting elements and the second light-emitting element emits green light, and the other emits blue light. The light-receiving and light-emitting element emits red light and has a light-receiving function.

[0186] For example, when detecting a touch operation using a light-emitting / receiving element, it is preferable that the light emitted from the light source is less visible to the user. Because blue light is less visible than green light, it is preferable that a light-emitting element that emits blue light be used as the light source. Therefore, it is preferable that the light-emitting / receiving element has a function of receiving blue light. However, this is not limited to this, and the light-emitting element used as the light source can be appropriately selected depending on the sensitivity of the light-emitting / receiving element.

[0187] As described above, pixels with various arrangements can be applied to the display device of this embodiment mode.

[0188] [Device Structure] Next, detailed structures of a light-emitting element, a light-receiving element, and a light-emitting and light-emitting element that can be used in the display device of one embodiment of the present invention will be described.

[0189] The display device of one embodiment of the present invention may be any of a top emission type that emits light in a direction opposite to a substrate on which a light-emitting element is formed, a bottom emission type that emits light toward a substrate on which a light-emitting element is formed, and a dual emission type that emits light to both sides.

[0190] In this embodiment, a top-emission display device will be described as an example.

[0191] In this specification, unless otherwise specified, even when describing a configuration having a plurality of elements (light-emitting elements, light-emitting layers, etc.), when describing matters common to each element, the alphabet will be omitted. For example, when describing matters common to light-emitting layer 283R and light-emitting layer 283G, etc., they may be referred to as light-emitting layer 283.

[0192] A display device 280A shown in FIG. 17A has a light receiving element 270PD, a light emitting element 270R that emits red (R) light, a light emitting element 270G that emits green (G) light, and a light emitting element 270B that emits blue (B) light.

[0193] Each light-emitting element has a pixel electrode 271, a hole injection layer 281, a hole transport layer 282, a light-emitting layer, an electron transport layer 284, an electron injection layer 285, and a common electrode 275 stacked in this order. Light-emitting element 270R has a light-emitting layer 283R, light-emitting element 270G has a light-emitting layer 283G, and light-emitting element 270B has a light-emitting layer 283B. Light-emitting layer 283R contains a light-emitting material that emits red light, light-emitting layer 283G contains a light-emitting material that emits green light, and light-emitting layer 283B contains a light-emitting material that emits blue light.

[0194] The light emitting element is an electroluminescent element that emits light toward the common electrode 275 when a voltage is applied between the pixel electrode 271 and the common electrode 275 .

[0195] The light receiving element 270PD has a pixel electrode 271, a hole injection layer 281, a hole transport layer 282, an active layer 273, an electron transport layer 284, an electron injection layer 285, and a common electrode 275 stacked in this order.

[0196] The light receiving element 270PD is a photoelectric conversion element that receives light incident from outside the display device 280A and converts it into an electrical signal.

[0197] In this embodiment, in both the light-emitting element and the light-receiving element, the pixel electrode 271 functions as an anode, and the common electrode 275 functions as a cathode. In other words, by applying a reverse bias between the pixel electrode 271 and the common electrode 275 and driving the light-receiving element, the light incident on the light-receiving element can be detected, an electric charge can be generated, and the electric charge can be extracted as a current.

[0198] In the display device of this embodiment, an organic compound is used for the active layer 273 of the light-receiving element 270PD. The layers of the light-receiving element 270PD other than the active layer 273 can be configured in common with the light-emitting element. Therefore, by simply adding a step of forming the active layer 273 to the manufacturing process of the light-emitting element, the light-receiving element 270PD can be formed in parallel with the formation of the light-emitting element. Furthermore, the light-emitting element and the light-receiving element 270PD can be formed on the same substrate. Therefore, the light-receiving element 270PD can be incorporated into the display device without significantly increasing the number of manufacturing steps.

[0199] The display device 280A shows an example in which the light receiving element 270PD and the light emitting element have a common configuration, except that the active layer 273 of the light receiving element 270PD and the light emitting layer 283 of the light emitting element are fabricated separately. However, the configuration of the light receiving element 270PD and the light emitting element is not limited to this. The light receiving element 270PD and the light emitting element may have layers fabricated separately from each other, in addition to the active layer 273 and the light emitting layer 283. It is preferable that the light receiving element 270PD and the light emitting element have one or more layers used in common (common layers). This allows the light receiving element 270PD to be incorporated into the display device without significantly increasing the number of manufacturing steps.

[0200] A conductive film that transmits visible light is used for the electrode from which light is extracted, between the pixel electrode 271 and the common electrode 275. It is preferable to use a conductive film that reflects visible light for the electrode from which light is not extracted.

[0201] The light-emitting element included in the display device of this embodiment preferably has a micro-optical resonator (microcavity) structure. Therefore, one of a pair of electrodes included in the light-emitting element preferably has an electrode that is transparent and reflective to visible light (semi-transmissive / semi-reflective electrode), and the other preferably has an electrode that is reflective to visible light (reflective electrode). When the light-emitting element has a microcavity structure, light emitted from the light-emitting layer can be resonated between both electrodes, thereby intensifying the light emitted from the light-emitting element.

[0202] The semi-transmitting / semi-reflective electrode can have a laminated structure of a reflective electrode and an electrode that is transparent to visible light (also called a transparent electrode).

[0203] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode with a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more for the light emitting element. The visible light reflectance of the semi-transmissive / semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. In addition, the resistivity of these electrodes is 1×10 -2 When the light-emitting element emits near-infrared light (light with a wavelength of 750 nm or more and 1300 nm or less), the transmittance or reflectance of these electrodes for near-infrared light preferably satisfies the above-mentioned numerical range, similar to the transmittance or reflectance for visible light.

[0204] The light-emitting element has at least the light-emitting layer 283. The light-emitting element may further have, in addition to the light-emitting layer 283, a layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a hole-blocking material, a substance with high electron-transport properties, a substance with high electron-injection properties, an electron-blocking material, a bipolar substance (a substance with high electron-transport properties and high hole-transport properties), or the like.

[0205] For example, the light-emitting element and the light-receiving element may have one or more layers of the hole injection layer, hole transport layer, electron transport layer, and electron injection layer in common, or the light-emitting element and the light-receiving element may have one or more layers of the hole injection layer, hole transport layer, electron transport layer, and electron injection layer formed differently from each other.

[0206] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a material with high hole injection properties, such as a composite material containing a hole transport material and an acceptor material (electron acceptor material), or an aromatic amine compound.

[0207] In a light-emitting element, the hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light-emitting layer. In a light-receiving element, the hole transport layer is a layer that transports holes generated in the active layer based on incident light to the anode. The hole transport layer is a layer that contains a hole transport material. The hole transport material is a material having a concentration of 1×10 -6 cm 2 A material having a hole mobility of 1 / Vs or more is preferred. Note that other materials can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a material having a high hole transporting property, such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, a furan derivative, etc.) or an aromatic amine (a compound having an aromatic amine skeleton), is preferred.

[0208] In a light-emitting element, the electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. In a light-receiving element, the electron transport layer is a layer that transports electrons generated in the active layer based on incident light to the cathode. The electron transport layer is a layer that contains an electron transporting material. The electron transporting material is a material having a 1×10 -6 cm 2A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher electron transporting property than holes. Examples of electron-transporting materials that can be used include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, and metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and π-electron-deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0209] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a material with high electron injection properties. Examples of the material with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the material with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0210] The light-emitting layer 283 is a layer containing a light-emitting substance. The light-emitting layer 283 can have one or more types of light-emitting substances. As the light-emitting substance, a substance that emits light of a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. Furthermore, as the light-emitting substance, a substance that emits near-infrared light can also be used.

[0211] Examples of light-emitting materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0212] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0213] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton; organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand; platinum complexes; and rare earth metal complexes.

[0214] The light-emitting layer 283 may contain one or more organic compounds (host materials, assist materials, etc.) in addition to a light-emitting substance (guest material). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material can be used. Furthermore, as the one or more organic compounds, a bipolar material or a TADF material can be used.

[0215] The light-emitting layer 283 preferably includes, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. This structure allows efficient emission using Exciplex-Triplet Energy Transfer (ExTET), which is energy transfer from an exciplex to a light-emitting substance (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting substance, the energy transfer becomes smooth and light emission can be achieved efficiently. This structure simultaneously enables high efficiency, low-voltage operation, and long life of the light-emitting element.

[0216] As a combination of materials that form an exciplex, it is preferable that the HOMO level (highest occupied molecular orbital level) of the hole-transporting material is equal to or higher than the HOMO level of the electron-transporting material. It is also preferable that the LUMO level (lowest unoccupied molecular orbital level) of the hole-transporting material is equal to or higher than the LUMO level of the electron-transporting material. The LUMO level and HOMO level of the material can be derived from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV).

[0217] The formation of exciplexes can be confirmed, for example, by comparing the emission spectra of the hole-transporting material, the electron-transporting material, and the mixed film of these materials and observing the phenomenon that the emission spectrum of the mixed film is shifted to longer wavelengths than the emission spectra of each material (or has a new peak at longer wavelengths). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of the hole-transporting material, the transient PL of the electron-transporting material, and the mixed film of these materials and observing differences in transient response, such as the transient PL lifetime of the mixed film having a longer-lived component or a larger proportion of delayed components than the transient PL lifetimes of the individual materials. The above-mentioned transient PL can also be interpreted as transient electroluminescence (EL). In other words, the formation of exciplexes can also be confirmed by comparing the transient EL of the hole-transporting material, the transient EL of the electron-transporting material, and the mixed film of these materials and observing differences in transient response.

[0218] The active layer 273 includes a semiconductor. Examples of the semiconductor include inorganic semiconductors such as silicon and organic semiconductors including organic compounds. In this embodiment, an example in which an organic semiconductor is used as the semiconductor included in the active layer 273 is shown. By using an organic semiconductor, the light-emitting layer 283 and the active layer 273 can be formed by the same method (for example, vacuum deposition), which is preferable because it allows the use of a common manufacturing device.

[0219] The active layer 273 has an n-type semiconductor material, such as fullerene (e.g., C 60 , C 70Examples of electron-accepting organic semiconductor materials include fullerene derivatives and other fullerenes. Fullerenes have a soccer ball-like shape, which is energetically stable. Fullerenes have deep (low) HOMO and LUMO levels. Because fullerenes have a deep LUMO level, they have extremely high electron-accepting (acceptor) properties. Normally, when the π-electron conjugation (resonance) spreads on a plane, as in benzene, the electron-donating (donor) properties increase, but fullerenes have a spherical shape, so they have high electron-accepting properties despite the large spread of π-electrons. High electron-accepting properties allow charge separation to occur quickly and efficiently, making them useful as light-receiving elements. C 60 , C 70 Both have a wide absorption band in the visible light region, especially C 70 is C 60 It is preferred because it has a larger π-electron conjugated system and a wide absorption band in the long wavelength region compared to the above.

[0220] Furthermore, examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0221] Examples of the p-type semiconductor material of the active layer 273 include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin phthalocyanine (SnPc), and quinacridone.

[0222] Examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, compounds having an aromatic amine skeleton, etc. Examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indolocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, polythiophene derivatives, etc.

[0223] The HOMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the HOMO level of the electron-accepting organic semiconductor material, and the LUMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the LUMO level of the electron-accepting organic semiconductor material.

[0224] It is preferable to use a spherical fullerene as the electron-accepting organic semiconductor material and a planar organic semiconductor material as the electron-donating organic semiconductor material. Molecules with similar shapes tend to aggregate together, and when molecules of the same type aggregate, the energy levels of their molecular orbitals become close, which can improve carrier transport properties.

[0225] For example, the active layer 273 is preferably formed by co-evaporating an n-type semiconductor and a p-type semiconductor, or alternatively, the active layer 273 may be formed by laminating an n-type semiconductor and a p-type semiconductor.

[0226] The light-emitting element and the light-receiving element can be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound. The layers constituting the light-emitting element and the light-receiving element can be formed by a method such as vapor deposition (including vacuum vapor deposition), a transfer method, a printing method, an inkjet method, or a coating method.

[0227] Display device 280B shown in FIG. 17B differs from display device 280A in that light receiving element 270PD and light emitting element 270R have the same configuration.

[0228] The light receiving element 270PD and the light emitting element 270R have the active layer 273 and the light emitting layer 283R in common.

[0229] Here, it is preferable that light receiving element 270PD has a common configuration with a light emitting element that emits light of a longer wavelength than the light to be detected. For example, light receiving element 270PD configured to detect blue light can have the same configuration as one or both of light emitting element 270R and light emitting element 270G. For example, light receiving element 270PD configured to detect green light can have the same configuration as light emitting element 270R.

[0230] By using a common configuration for the light receiving element 270PD and the light emitting element 270R, the number of film formation steps and the number of masks can be reduced compared to a configuration in which the light receiving element 270PD and the light emitting element 270R have separate layers, thereby reducing the manufacturing steps and manufacturing costs of the display device.

[0231] Furthermore, by using a common configuration for the light receiving element 270PD and the light emitting element 270R, the margin for misalignment can be narrowed compared to a configuration in which the light receiving element 270PD and the light emitting element 270R have separate layers. This allows for an increased pixel aperture ratio, improving the light extraction efficiency of the display device. This also extends the life of the light emitting element. Furthermore, the display device can display high brightness. Furthermore, it also allows for higher resolution display devices.

[0232] Light-emitting layer 283R includes a light-emitting material that emits red light. Active layer 273 includes an organic compound that absorbs light with a wavelength shorter than red (for example, one or both of green light and blue light). Active layer 273 preferably includes an organic compound that does not easily absorb red light and absorbs light with a wavelength shorter than red. This allows red light to be extracted efficiently from light-emitting element 270R, and light-receiving element 270PD to detect light with a wavelength shorter than red with high accuracy.

[0233] Furthermore, in the display device 280B, an example is shown in which the light emitting element 270R and the light receiving element 270PD have the same configuration, but the light emitting element 270R and the light receiving element 270PD may have optical adjustment layers of different thicknesses.

[0234] 18A and 18B includes a light receiving / emitting element 270SR that emits red (R) light and has a light receiving function, a light emitting element 270G, and a light emitting element 270B. The configuration of the light emitting element 270G and the light emitting element 270B can be based on the configuration of the above-described display device 280A, etc.

[0235] The light emitting / receiving element 270SR has, stacked in this order, a pixel electrode 271, a hole injection layer 281, a hole transport layer 282, an active layer 273, a light emitting layer 283R, an electron transport layer 284, an electron injection layer 285, and a common electrode 275. The light emitting / receiving element 270SR has the same configuration as the light emitting element 270R and the light receiving element 270PD exemplified in the display device 280B.

[0236] 18A shows a case where the light emitting / receiving element 270SR functions as a light emitting element. In FIG. 18A, an example is shown in which the light emitting element 270B emits blue light, the light emitting element 270G emits green light, and the light emitting / receiving element 270SR emits red light.

[0237] Fig. 18B shows a case where the light receiving / emitting element 270SR functions as a light receiving element. Fig. 18B shows an example where the light receiving / emitting element 270SR receives blue light emitted by the light emitting element 270B and green light emitted by the light emitting element 270G.

[0238] The light emitting element 270B, the light emitting element 270G, and the light emitting / receiving element 270SR each have a pixel electrode 271 and a common electrode 275. In the present embodiment, a case will be described as an example in which the pixel electrode 271 functions as an anode and the common electrode 275 functions as a cathode. The light emitting / receiving element 270SR is driven by applying a reverse bias between the pixel electrode 271 and the common electrode 275, whereby it can detect light incident on the light emitting / receiving element 270SR, generate electric charges, and extract the charges as a current.

[0239] The light emitting / receiving element 270SR can be said to have a configuration in which the active layer 273 is added to the light emitting element. In other words, the light emitting / receiving element 270SR can be formed in parallel with the formation of the light emitting element by simply adding a process for forming the active layer 273 to the manufacturing process of the light emitting element. Furthermore, the light emitting element and the light emitting / receiving element can be formed on the same substrate. Therefore, it is possible to provide the display unit with either or both of an imaging function and a sensing function without significantly increasing the manufacturing process.

[0240] There are no limitations on the stacking order of the light-emitting layer 283R and the active layer 273. Figures 18A and 18B show an example in which the active layer 273 is provided on the hole transport layer 282, and the light-emitting layer 283R is provided on the active layer 273. The stacking order of the light-emitting layer 283R and the active layer 273 may be reversed.

[0241] Furthermore, the light emitting / receiving element may not have at least one layer selected from the hole injection layer 281, the hole transport layer 282, the electron transport layer 284, and the electron injection layer 285. The light emitting / receiving element may also have other functional layers such as a hole blocking layer and an electron blocking layer.

[0242] In the light emitting / receiving element, a conductive film that transmits visible light is used for the electrode on the light extraction side, and a conductive film that reflects visible light is preferably used for the electrode on the non-light extraction side.

[0243] The functions and materials of the layers constituting the light emitting / receiving element are similar to those of the layers constituting the light emitting element and the light receiving element, and therefore detailed description thereof will be omitted.

[0244] 18C to 18G show examples of the stacked structure of the light emitting and receiving element.

[0245] The light emitting / receiving element shown in FIG. 18C has a first electrode 277, a hole injection layer 281, a hole transport layer 282, a light emitting layer 283R, an active layer 273, an electron transport layer 284, an electron injection layer 285, and a second electrode 278.

[0246] FIG. 18C shows an example in which a light-emitting layer 283R is provided on a hole-transporting layer 282, and an active layer 273 is laminated on the light-emitting layer 283R.

[0247] As shown in FIGS. 18A to 18C, the active layer 273 and the light emitting layer 283R may be in contact with each other.

[0248] Furthermore, a buffer layer is preferably provided between the active layer 273 and the light-emitting layer 283R. In this case, the buffer layer preferably has hole transport properties and electron transport properties. For example, a bipolar substance is preferably used for the buffer layer. Alternatively, at least one layer selected from a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a hole blocking layer, and an electron blocking layer can be used as the buffer layer. FIG. 18D shows an example in which a hole transport layer 282 is used as the buffer layer.

[0249] By providing a buffer layer between the active layer 273 and the light-emitting layer 283R, it is possible to suppress the transfer of excitation energy from the light-emitting layer 283R to the active layer 273. In addition, the buffer layer can also be used to adjust the optical path length (cavity length) of the microcavity structure. Therefore, a light-emitting / receiving element having a buffer layer between the active layer 273 and the light-emitting layer 283R can obtain high light-emitting efficiency.

[0250] FIG. 18E shows an example of a laminated structure in which a hole transport layer 282-1, an active layer 273, a hole transport layer 282-2, and an emitting layer 283R are laminated in this order on a hole injection layer 281. The hole transport layer 282-2 functions as a buffer layer. The hole transport layer 282-1 and the hole transport layer 281-2 may contain the same material or different materials. Alternatively, a layer that can be used as the buffer layer described above may be used instead of the hole transport layer 281-2. Alternatively, the positions of the active layer 273 and the emitting layer 283R may be interchanged.

[0251] 18F differs from the light emitting / receiving element shown in Fig. 18A in that it does not have the hole transport layer 282. In this way, the light emitting / receiving element may not have at least one layer among the hole injection layer 281, the hole transport layer 282, the electron transport layer 284, and the electron injection layer 285. The light emitting / receiving element may also have other functional layers such as a hole blocking layer or an electron blocking layer.

[0252] The light emitting / receiving device shown in FIG. 18G differs from the light emitting / receiving device shown in FIG. 18A in that it does not have the active layer 273 and the light emitting layer 283R, but has a layer 289 that serves as both the light emitting layer and the active layer.

[0253] As a layer that serves as both a light-emitting layer and an active layer, for example, a layer containing three materials: an n-type semiconductor that can be used for the active layer 273, a p-type semiconductor that can be used for the active layer 273, and a light-emitting substance that can be used for the light-emitting layer 283R can be used.

[0254] It is preferable that the lowest energy absorption band in the absorption spectrum of the mixed material of n-type and p-type semiconductors does not overlap with the maximum peak in the emission spectrum (PL spectrum) of the luminescent substance, and it is more preferable that they are sufficiently separated from each other.

[0255] [Display device configuration example 2] A detailed structure of a display device according to one embodiment of the present invention will be described below, particularly an example of a display device including a light-receiving element and a light-emitting element.

[0256] [Configuration Example 2-1] 19A shows a cross-sectional view of the display device 300 A. The display device 300 A includes a substrate 351, a substrate 352, a light receiving element 310, a conductive layer 360, and a light emitting element 390.

[0257] The light-emitting element 390 has a pixel electrode 391, a buffer layer 312, a light-emitting layer 393, a buffer layer 314, and a common electrode 315 stacked in this order. The buffer layer 312 can have one or both of a hole injection layer and a hole transport layer. The light-emitting layer 393 contains an organic compound. The buffer layer 314 can have one or both of an electron injection layer and an electron transport layer. The light-emitting element 390 has a function of emitting visible light 321. Note that the display device 300A may further have a light-emitting element that has a function of emitting infrared light.

[0258] The light receiving element 310 has a pixel electrode 311, a buffer layer 312, an active layer 313, a buffer layer 314, and a common electrode 315 stacked in this order. The active layer 313 contains an organic compound. The light receiving element 310 has a function of detecting visible light. The light receiving element 310 may also have a function of detecting infrared light.

[0259] The buffer layer 312, the buffer layer 314, and the common electrode 315 are layers common to the light-emitting element 390 and the light-receiving element 310, and are provided across these elements. The buffer layer 312, the buffer layer 314, and the common electrode 315 have portions that overlap with the active layer 313 and the pixel electrode 311, portions that overlap with the light-emitting layer 393 and the pixel electrode 391, and portions that do not overlap with either of them.

[0260] In the present embodiment, the pixel electrode functions as an anode and the common electrode 315 functions as a cathode in both the light-emitting element 390 and the light-receiving element 310. In other words, by driving the light-receiving element 310 by applying a reverse bias between the pixel electrode 311 and the common electrode 315, the display device 300A can detect light incident on the light-receiving element 310, generate charges, and extract them as a current.

[0261] The pixel electrode 311, the pixel electrode 391, the buffer layer 312, the active layer 313, the buffer layer 314, the light-emitting layer 393, and the common electrode 315 may each have a single-layer structure or a multilayer structure.

[0262] The pixel electrode 311 and the pixel electrode 391 are each located on an insulating layer 414. Each pixel electrode can be formed using the same material and in the same process. Ends of the pixel electrode 311 and the pixel electrode 391 are covered with an insulating layer 416. Two adjacent pixel electrodes are electrically insulated (or electrically separated) from each other by the insulating layer 416.

[0263] An organic insulating film is suitable for the insulating layer 416. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. The insulating layer 416 is a layer that transmits visible light. Instead of the insulating layer 416, a partition wall that blocks visible light may be provided.

[0264] The common electrode 315 is a layer that is used in common by the light receiving element 310 and the light emitting element 390 .

[0265] The materials and film thicknesses of the pair of electrodes of the light-receiving element 310 and the light-emitting element 390 can be made the same, which leads to a reduction in manufacturing cost and simplification of the manufacturing process of the display device.

[0266] The conductive layer 360 is located between the pixel electrode 391 and the pixel electrode 311 in a plan view. The conductive layer 360 is formed by processing the same conductive film as either or both of the pixel electrode 391 and the pixel electrode 311. The conductive layer 360 has a region in contact with the buffer layer 312 in the opening of the insulating layer 416. Furthermore, the conductive layer 360 is electrically connected to a wiring to which a predetermined potential is applied in a region not shown.

[0267] The display device 300A includes a light receiving element 310, a light emitting element 390, a transistor 331, a transistor 332, and the like between a pair of substrates (substrate 351 and substrate 352).

[0268] In the light-receiving element 310, the buffer layer 312, active layer 313, and buffer layer 314 located between the pixel electrode 311 and the common electrode 315 can also be called organic layers (layers containing an organic compound). The pixel electrode 311 preferably has a function of reflecting visible light. The common electrode 315 has a function of transmitting visible light. Note that, when the light-receiving element 310 is configured to detect infrared light, the common electrode 315 has a function of transmitting infrared light. Furthermore, the pixel electrode 311 preferably has a function of reflecting infrared light.

[0269] The light receiving element 310 has a function of detecting light. Specifically, the light receiving element 310 is a photoelectric conversion element that receives light 322 incident from outside the display device 300A and converts the received light into an electrical signal. The light 322 can also be said to be light emitted by the light emitting element 390 and reflected by an object. The light 322 may also be incident on the light receiving element 310 via a lens or the like provided in the display device 300A.

[0270] In the light-emitting element 390, the buffer layer 312, the light-emitting layer 393, and the buffer layer 314 located between the pixel electrode 391 and the common electrode 315 can be collectively referred to as an EL layer. The EL layer has at least the light-emitting layer 393. As described above, the pixel electrode 391 preferably has a function of reflecting visible light. Furthermore, the common electrode 315 has a function of transmitting visible light. Note that, when the display device 300A has a configuration including a light-emitting element that emits infrared light, the common electrode 315 has a function of transmitting infrared light. Furthermore, the pixel electrode 391 preferably has a function of reflecting infrared light.

[0271] It is preferable that a micro-optical resonator (microcavity) structure is applied to the light-emitting element included in the display device of this embodiment. The light-emitting element 390 may have an optical adjustment layer between the pixel electrode 391 and the common electrode 315. By applying the micro-resonator structure, it is possible to intensify and extract light of a specific color from each light-emitting element.

[0272] The light-emitting element 390 has a function of emitting visible light. Specifically, the light-emitting element 390 is an electroluminescent element that emits light (here, visible light 321) toward the substrate 352 by applying a voltage between the pixel electrode 391 and the common electrode 315.

[0273] The pixel electrode 311 of the light-receiving element 310 is electrically connected to the source or drain of the transistor 331 through an opening provided in the insulating layer 414. The pixel electrode 391 of the light-emitting element 390 is electrically connected to the source or drain of the transistor 332 through an opening provided in the insulating layer 414.

[0274] The transistor 331 and the transistor 332 are adjacent to each other on the same layer (substrate 351 in FIG. 19A).

[0275] At least a part of the circuit electrically connected to the light receiving element 310 is preferably formed using the same material and in the same process as the circuit electrically connected to the light emitting element 390. This allows the display device to be thinner and the manufacturing process to be simplified compared to when the two circuits are formed separately.

[0276] Preferably, the light receiving element 310 and the light emitting element 390 are each covered with a protective layer 395. In Fig. 19A, the protective layer 395 is provided on and in contact with the common electrode 315. By providing the protective layer 395, it is possible to prevent impurities such as water from entering the light receiving element 310 and the light emitting element 390, thereby improving the reliability of the light receiving element 310 and the light emitting element 390. In addition, the protective layer 395 and the substrate 352 are bonded together by an adhesive layer 342.

[0277] A light-shielding layer 358 is provided on the surface of the substrate 352 facing the substrate 351. The light-shielding layer 358 has openings at positions overlapping the light-emitting element 390 and the light-receiving element 310.

[0278] Here, the light receiving element 310 detects light emitted by the light emitting element 390 and reflected by the object. However, there is a case where the light emitted by the light emitting element 390 is reflected within the display device 300A and enters the light receiving element 310 without passing through the object. The light blocking layer 358 can suppress the influence of such stray light. For example, if the light blocking layer 358 is not provided, the light 323 emitted by the light emitting element 390 may be reflected by the substrate 352, and the reflected light 324 may enter the light receiving element 310. By providing the light blocking layer 358, it is possible to prevent the reflected light 324 from entering the light receiving element 310. This reduces noise and improves the sensitivity of the sensor using the light receiving element 310.

[0279] The light-shielding layer 358 can be made of a material that blocks light emitted from the light-emitting elements. The light-shielding layer 358 preferably absorbs visible light. For example, the light-shielding layer 358 can be made of a black matrix using a metal material or a resin material containing a pigment (such as carbon black) or a dye. The light-shielding layer 358 may have a laminated structure of red, green, and blue color filters.

[0280] [Configuration Example 2-2] The display device 300B shown in FIG. 19B differs from the display device 300A described above mainly in that it has a lens 349.

[0281] Lens 349 is provided on the substrate 351 side of substrate 352. Light 322 incident from the outside is incident on light receiving element 310 via lens 349. It is preferable that lens 349 and substrate 352 are made of a material that is highly transparent to visible light.

[0282] Light is incident on the light receiving element 310 via the lens 349, thereby narrowing the range of light incident on the light receiving element 310. This makes it possible to prevent the imaging ranges of the multiple light receiving elements 310 from overlapping, and to capture clear images with little blur.

[0283] Furthermore, the lens 349 can condense the incident light, thereby increasing the amount of light incident on the light receiving element 310. This increases the photoelectric conversion efficiency of the light receiving element 310.

[0284] [Configuration Example 2-3] A display device 300C shown in FIG. 19C differs from the display device 300A described above mainly in that the shape of the light-shielding layer 358 is different.

[0285] The light-shielding layer 358 is provided such that, in a plan view, the opening overlapping the light-receiving element 310 is located inside the light-receiving region of the light-receiving element 310. The smaller the diameter of the opening of the light-shielding layer 358 overlapping with the light-receiving element 310, the narrower the range of light incident on the light-receiving element 310 can be. This makes it possible to prevent the imaging ranges of the multiple light-receiving elements 310 from overlapping, allowing for the capture of clear images with little blur.

[0286] For example, the area of ​​the opening in the light-shielding layer 358 can be 80% or less, 70% or less, 60% or less, 50% or less, or 40% or less of the area of ​​the light-receiving region of the light-receiving element 310, and can be 1% or more, 5% or more, or 10% or more. The smaller the area of ​​the opening in the light-shielding layer 358, the clearer the image can be captured. On the other hand, if the area of ​​the opening is too small, the amount of light reaching the light-receiving element 310 may decrease, resulting in a decrease in light-receiving sensitivity. Therefore, it is preferable to set the area appropriately within the above-mentioned range. Note that the above-mentioned upper and lower limits can be combined arbitrarily. Furthermore, the light-receiving region of the light-receiving element 310 can be rephrased as the opening in the insulating layer 416.

[0287] The center of the opening of the light-shielding layer 358 that overlaps with the light-receiving element 310 may be offset from the center of the light-receiving region of the light-receiving element 310 in a planar view. Furthermore, the opening of the light-shielding layer 358 may not overlap with the light-receiving region of the light-receiving element 310 in a planar view. This allows the light-receiving element 310 to receive only obliquely directed light that has passed through the opening of the light-shielding layer 358. This makes it possible to more effectively limit the range of light that enters the light-receiving element 310, thereby enabling a clear image to be captured.

[0288] [Configuration Example 2-4] The display device 300D shown in FIG. 20A differs from the display device 300A described above mainly in that the buffer layer 312 is not a common layer.

[0289] The light receiving element 310 has a pixel electrode 311, a buffer layer 312, an active layer 313, a buffer layer 314, and a common electrode 315. The light emitting element 390 has a pixel electrode 391, a buffer layer 392, a light emitting layer 393, a buffer layer 314, and a common electrode 315. The active layer 313, the buffer layer 312, the light emitting layer 393, and the buffer layer 392 each have an island-shaped top surface.

[0290] Buffer layer 312 and buffer layer 392 may comprise different materials or the same materials.

[0291] In this way, by forming separate buffer layers for the light-emitting element 390 and the light-receiving element 310, the degree of freedom in selecting materials for the buffer layers used for the light-emitting element 390 and the light-receiving element 310 is increased, making optimization easier. Furthermore, by using the buffer layer 314 and the common electrode 315 as a common layer, the manufacturing process is simplified and manufacturing costs can be reduced compared to when the light-emitting element 390 and the light-receiving element 310 are manufactured separately.

[0292] The conductive layer 360 has a region in contact with the buffer layer 314 in the opening of the insulating layer 416. This makes it possible to block side leakage current that may flow between the pixel electrode 311 and the pixel electrode 391 via the buffer layer 314.

[0293] [Configuration Example 2-5] A display device 300E shown in FIG. 20B differs from the display device 300A described above mainly in that the buffer layer 314 is not a common layer.

[0294] The light-receiving element 310 has a pixel electrode 311, a buffer layer 312, an active layer 313, a buffer layer 314, and a common electrode 315. The light-emitting element 390 has a pixel electrode 391, a buffer layer 312, a light-emitting layer 393, a buffer layer 394, and a common electrode 315. The active layer 313, the buffer layer 314, the light-emitting layer 393, and the buffer layer 394 each have an island-shaped top surface.

[0295] Buffer layer 314 and buffer layer 394 may comprise different materials or the same materials.

[0296] In this way, by forming separate buffer layers for the light-emitting element 390 and the light-receiving element 310, the degree of freedom in selecting the materials for the buffer layers used for the light-emitting element 390 and the light-receiving element 310 is increased, making optimization easier. Furthermore, by using the buffer layer 312 and the common electrode 315 as a common layer, the manufacturing process is simplified and manufacturing costs can be reduced compared to when the light-emitting element 390 and the light-receiving element 310 are manufactured separately.

[0297] [Display device configuration example 3] A detailed structure of a display device according to one embodiment of the present invention will be described below, particularly an example of a display device including a light-emitting and light-emitting element.

[0298] In the following, the same parts as those described above will be referred to and explanations thereof may be omitted.

[0299] [Configuration Example 3-1] 21A shows a cross-sectional view of a display device 300G. The display device 300G includes a light emitting / receiving element 390SR, a light emitting element 390G, a light emitting element 390B, and a conductive layer 360.

[0300] The light emitting / receiving element 390SR functions as a light emitting element that emits red light 321R and as a photoelectric conversion element that receives light 322. The light emitting element 390G can emit green light 321G. The light emitting element 390B can emit blue light 321B.

[0301] The light emitting / receiving element 390SR has a pixel electrode 311, a buffer layer 312, an active layer 313, a light emitting layer 393R, a buffer layer 314, and a common electrode 315. The light emitting element 390G has a pixel electrode 391G, a buffer layer 312, a light emitting layer 393G, a buffer layer 314, and a common electrode 315. The light emitting element 390B has a pixel electrode 391B, a buffer layer 312, a light emitting layer 393B, a buffer layer 314, and a common electrode 315.

[0302] The buffer layer 312, the buffer layer 314, and the common electrode 315 are layers (common layers) common to the light emitting / receiving element 390SR, the light emitting element 390G, and the light emitting element 390B, and are provided across these elements. The active layer 313, the light emitting layer 393R, the light emitting layer 393G, and the light emitting layer 393B each have an island-like upper surface. Note that, although FIG. 21 shows an example in which the stack of the active layer 313 and the light emitting layer 393R, the light emitting layer 393G, and the light emitting layer 393B are provided separately from each other, they may have an overlapping area between adjacent layers.

[0303] As in the display device 300D or 300E, one of the buffer layer 312 and the buffer layer 314 may not be used as a common layer.

[0304] The pixel electrode 311 is electrically connected to one of the source and drain of the transistor 331. The pixel electrode 391G is electrically connected to one of the source and drain of the transistor 332G. The pixel electrode 391B is electrically connected to one of the source and drain of the transistor 332B.

[0305] In a plan view, the conductive layer 360 is located between the pixel electrode 391G and the pixel electrode 311. Although not shown here, the conductive layer 360 can also be disposed between the pixel electrode 391B and the pixel electrode 311. The conductive layer 360 is formed by processing the same conductive film as any one, two, or all of the pixel electrode 311, the pixel electrode 391G, and the pixel electrode 391B.

[0306] With this configuration, a display device with higher resolution can be realized.

[0307] [Configuration Example 3-2] A display device 300H shown in FIG. 21B differs from the display device 300G described above mainly in that the configuration of the light emitting / receiving element 390SR is different.

[0308] The light emitting / receiving element 390SR has a light emitting / receiving layer 318R in place of the active layer 313 and the light emitting layer 393R.

[0309] The light emitting / receiving layer 318R functions both as a light emitting layer and an active layer. For example, a layer containing the above-mentioned light emitting material, an n-type semiconductor, and a p-type semiconductor can be used.

[0310] By adopting such a structure, the manufacturing process can be further simplified, which facilitates cost reduction.

[0311] [Display device configuration example 4] A more specific structure of the display device of one embodiment of the present invention will be described below.

[0312] FIG. 22 shows a perspective view of display device 400, and FIG. 23A shows a cross-sectional view of display device 400.

[0313] The display device 400 has a configuration in which a substrate 353 and a substrate 354 are bonded together. In Fig. 22, the substrate 354 is clearly indicated by a dashed line.

[0314] The display device 400 includes a display unit 362, a circuit 364, wiring 365, etc. Fig. 22 shows an example in which an IC (integrated circuit) 373 and an FPC 372 are mounted on the display device 400. Therefore, the configuration shown in Fig. 22 can also be said to be a display module including the display device 400, an IC, and an FPC.

[0315] The circuit 364 can be, for example, a scanning line driver circuit.

[0316] The wiring 365 has a function of supplying signals and power to the display unit 362 and the circuit 364. The signals and power are input to the wiring 365 from the outside via the FPC 372 or input to the wiring 365 from the IC 373.

[0317] 22 shows an example in which an IC 373 is provided on a substrate 353 by a COG (Chip On Glass) method or a COF (Chip On Film) method. The IC 373 may be, for example, an IC having a scanning line driver circuit or a signal line driver circuit. The display device 400 and the display module may not include an IC. Alternatively, the IC may be mounted on an FPC by a COF method or the like.

[0318] Figure 23A shows an example of a cross section of the display device 400 shown in Figure 22, with a portion of the area including the FPC 372, a portion of the area including the circuit 364, a portion of the area including the display unit 362, and a portion of the area including the end portion cut away.

[0319] A display device 400 shown in FIG. 23A includes a transistor 408, a transistor 409, a transistor 410, a light-emitting element 390, a light-receiving element 310, a conductive layer 360, and the like between a substrate 353 and a substrate 354.

[0320] The substrate 354 and the protective layer 395 are bonded together via an adhesive layer 342, and a solid sealing structure is applied to the display device 400.

[0321] The substrate 353 and the insulating layer 412 are bonded together by an adhesive layer 355 .

[0322] The display device 400 is manufactured by first bonding a fabrication substrate provided with an insulating layer 412, each transistor, the light-receiving element 310, the light-emitting element 390, and the like to a substrate 354 provided with a light-shielding layer 358 and the like with an adhesive layer 342. Then, the fabrication substrate is peeled off, and a substrate 353 is bonded to the exposed surface using an adhesive layer 355, thereby transferring each component formed on the fabrication substrate to the substrate 353. The substrate 353 and the substrate 354 are preferably flexible. This can increase the flexibility of the display device 400.

[0323] The light-emitting element 390 has a layered structure in which a pixel electrode 391, a buffer layer 312, a light-emitting layer 393, a buffer layer 314, and a common electrode 315 are stacked in this order from the insulating layer 414 side. The pixel electrode 391 is connected to one of the source and the drain of the transistor 408 through an opening provided in the insulating layer 414. The transistor 408 has a function of controlling current flowing in the light-emitting element 390.

[0324] The light-receiving element 310 has a layered structure in which a pixel electrode 311, a buffer layer 312, an active layer 313, a buffer layer 314, and a common electrode 315 are stacked in this order from the insulating layer 414 side. The pixel electrode 311 is connected to one of the source and drain of the transistor 409 through an opening provided in the insulating layer 414. The transistor 409 has a function of controlling transfer of charges accumulated in the light-receiving element 310.

[0325] Light emitted by light emitting element 390 is emitted toward substrate 354. Light is incident on light receiving element 310 via substrate 354 and adhesive layer 342. It is preferable that substrate 354 be made of a material that is highly transparent to visible light.

[0326] The conductive layer 360 is located between the pixel electrode 391 and the pixel electrode 311 in a plan view. The conductive layer 360 has a region that is in contact with the buffer layer 312 in the opening of the insulating layer 416. The conductive layer 360 is also electrically connected to a wiring to which a predetermined potential is applied in a region not shown.

[0327] The pixel electrode 311, the pixel electrode 391, and the conductive layer 360 can be manufactured using the same material and in the same process. The buffer layer 312, the buffer layer 314, and the common electrode 315 are used in common for the light receiving element 310 and the light emitting element 390. The light receiving element 310 and the light emitting element 390 can have the same configuration except for the configurations of the active layer 313 and the light emitting layer 393. This allows the light receiving element 310 and the conductive layer 360 to be built into the display device 400 without significantly increasing the number of manufacturing processes.

[0328] A light-shielding layer 358 is provided on the surface of substrate 354 facing substrate 353. Light-shielding layer 358 has openings at positions overlapping with light-emitting element 390 and light-receiving element 310. By providing light-shielding layer 358, the range in which light is detected by light-receiving element 310 can be controlled. As described above, it is preferable to control the light incident on light-receiving element 310 by adjusting the position and area of ​​the opening in the light-shielding layer provided at a position overlapping with light-receiving element 310. Furthermore, by providing light-shielding layer 358, it is possible to prevent light from being directly incident on light-receiving element 310 from light-emitting element 390 without passing through an object. Therefore, a sensor with low noise and high sensitivity can be realized.

[0329] The edges of the pixel electrode 311 and the pixel electrode 391 are covered with an insulating layer 416. The pixel electrode 311 and the pixel electrode 391 contain a material that reflects visible light, and the common electrode 315 contains a material that transmits visible light.

[0330] The transistor 408, the transistor 409, and the transistor 410 are all formed over a substrate 353. These transistors can be manufactured using the same material and the same process.

[0331] An insulating layer 412, an insulating layer 411, an insulating layer 425, an insulating layer 415, an insulating layer 418, and an insulating layer 414 are provided over a substrate 353 with an adhesive layer 355 interposed therebetween. Parts of the insulating layer 411 and the insulating layer 425 each function as a gate insulating layer of each transistor. The insulating layer 415 and the insulating layer 418 are provided to cover the transistor. The insulating layer 414 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0332] At least one insulating layer covering the transistor is preferably made of a material that is resistant to the diffusion of impurities such as water and hydrogen. This allows the insulating layer to function as a barrier layer. With this structure, it is possible to effectively prevent impurities from diffusing into the transistor from the outside, thereby improving the reliability of the display device.

[0333] The insulating layer 411, the insulating layer 412, the insulating layer 425, the insulating layer 415, and the insulating layer 418 are preferably formed using an inorganic insulating film. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. A hafnium oxide film, a hafnium oxynitride film, a hafnium nitride oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used. Two or more of the above insulating films may be stacked.

[0334] Here, organic insulating films often have lower barrier properties than inorganic insulating films. Therefore, it is preferable that the organic insulating film has an opening near the edge of the display device 400. In region 428 shown in FIG. 23A, an opening is formed in insulating layer 414. This makes it possible to prevent impurities from entering from the edge of the display device 400 via the organic insulating film. Alternatively, the organic insulating film may be formed so that the edge of the organic insulating film is located inside the edge of the display device 400, so that the organic insulating film is not exposed at the edge of the display device 400.

[0335] In a region 428 near the edge of the display device 400, the insulating layer 418 and the protective layer 395 preferably contact each other through the opening in the insulating layer 414. In particular, it is preferable that the inorganic insulating film of the insulating layer 418 and the inorganic insulating film of the protective layer 395 contact each other. This makes it possible to prevent impurities from entering the display unit 362 from the outside through the organic insulating film. Therefore, the reliability of the display device 400 can be improved.

[0336] An organic insulating film is suitable for the insulating layer 414, which functions as a planarizing layer. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0337] By providing the protective layer 395 that covers the light emitting element 390 and the light receiving element 310, it is possible to prevent impurities such as water from entering the light emitting element 390 and the light receiving element 310, thereby improving their reliability.

[0338] The protective layer 395 may have a single layer or a laminated structure. For example, the protective layer 395 may have a laminated structure of an organic insulating film and an inorganic insulating film. In this case, it is preferable that the end of the inorganic insulating film extends further outward than the end of the organic insulating film.

[0339] FIG. 23B is a cross-sectional view of a transistor 401a that can be used for the transistor 408, the transistor 409, and the transistor 410.

[0340] The transistor 401a is provided over an insulating layer 412 (not shown) and includes a conductive layer 421 functioning as a first gate, an insulating layer 411 functioning as a first gate insulating layer, a semiconductor layer 431, an insulating layer 425 functioning as a second gate insulating layer, and a conductive layer 423 functioning as a second gate. The insulating layer 411 is located between the conductive layer 421 and the semiconductor layer 431. The insulating layer 425 is located between the conductive layer 423 and the semiconductor layer 431.

[0341] The semiconductor layer 431 has a region 431i and a pair of regions 431n. The region 431i functions as a channel formation region. One of the pair of regions 431n functions as a source and the other functions as a drain. The region 431n has a higher carrier concentration and higher conductivity than the region 431i. The conductive layer 422a and the conductive layer 422b are connected to the region 431n through openings provided in the insulating layer 418, the insulating layer 415, and the insulating layer 425.

[0342] 23C is a cross-sectional view of a transistor 401b that can be used for the transistor 408, the transistor 409, and the transistor 410. Also, Fig. 23C shows an example in which the insulating layer 415 is not provided. In the transistor 401b, the insulating layer 425 is processed in a similar manner to the conductive layer 423, and the insulating layer 418 and the region 431n are in contact with each other.

[0343] Note that 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 transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0344] The transistors 408, 409, and 410 each have a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected and supplied with the same signal to drive the transistors. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0345] 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 crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0346] The semiconductor layer of the transistor preferably contains a metal oxide (also referred to as an oxide semiconductor). Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

[0347] The semiconductor layer preferably contains, for example, indium, M (wherein M is one or more elements selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more elements selected from aluminum, gallium, yttrium, and tin.

[0348] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) as the semiconductor layer.

[0349] When the semiconductor layer 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 M. Examples of atomic ratios of metal elements in such In-M-Zn oxides include compositions in which In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:1.2 or thereabouts, In:M:Zn=2:1:3 or thereabouts, In:M:Zn=3:1:2 or thereabouts, In:M:Zn=4:2:3 or thereabouts, In:M:Zn=4:2:4.1 or thereabouts, In:M:Zn=5:1:3 or thereabouts, In:M:Zn=5:1:6 or thereabouts, In:M:Zn=5:1:7 or thereabouts, In:M:Zn=5:1:8 or thereabouts, In:M:Zn=6:1:6 or thereabouts, and In:M:Zn=5:2:5 or thereabouts, etc. Note that "nearby compositions" includes a range of ±30% of the desired atomic ratio.

[0350] For example, when describing a composition with an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, this includes a case where, when the atomic ratio of In is 4, the atomic ratio of Ga is 1 to 3 and the atomic ratio of Zn is 2 to 4. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, this includes a case where, when the atomic ratio of In is 5, the atomic ratio of Ga is greater than 0.1 and less than 2 and the atomic ratio of Zn is greater than 5 and less than 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, this includes a case where, when the atomic ratio of In is 1, the atomic ratio of Ga is greater than 0.1 and less than 2 and the atomic ratio of Zn is greater than 0.1 and less than 2.

[0351] The transistor 410 included in the circuit 364 may have the same structure as the transistors 408 and 409 included in the display portion 362 or may have different structures. The transistors included in the circuit 364 may all have the same structure or may have two or more types of structures. Similarly, the transistors included in the display portion 362 may all have the same structure or may have two or more types of structures.

[0352] A connection portion 404 is provided in an area of ​​the substrate 353 where the substrate 354 does not overlap. In the connection portion 404, the wiring 365 is electrically connected to the FPC 372 via a conductive layer 366 and a connection layer 442. The conductive layer 366, which is obtained by processing the same conductive film as the pixel electrodes 311 and 391, is exposed on the upper surface of the connection portion 404. This allows the connection portion 404 and the FPC 372 to be electrically connected via the connection layer 442.

[0353] Various optical members can be disposed on the outside of substrate 354. 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, an antistatic 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 scratches caused by use, an impact absorbing layer, etc. may be disposed on the outside of substrate 354.

[0354] The flexibility of the display device can be increased by using a flexible material for the substrate 353 and the substrate 354. Furthermore, without being limited thereto, the substrate 353 and the substrate 354 can be made of glass, quartz, ceramic, sapphire, resin, or the like.

[0355] The adhesive layer can be made of various curable adhesives, such as photo-curable adhesives (e.g., ultraviolet curable), reactive curable adhesives, thermosetting adhesives, and anaerobic adhesives. 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, etc., may also be used.

[0356] The connection layer may be made of an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0357] Materials that can be used for conductive layers such as the gate, source, and drain of a transistor, as well as various wirings and electrodes that constitute a display device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, and alloys containing these metals as main components, etc. Films containing these materials can be used as a single layer or a stacked layer structure.

[0358] Examples of light-transmitting conductive materials include conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metal materials, can be used. Alternatively, nitrides of such metal materials (e.g., titanium nitride) can be used. When using metal materials or alloy materials (or their nitrides), it is preferable to thin them sufficiently to ensure light-transmitting properties. A stacked film of the above materials can also be used as the conductive layer. For example, a stacked film of an alloy of silver and magnesium and indium tin oxide is preferable because it can enhance conductivity. These can also be used as conductive layers such as various wirings and electrodes constituting a display device, or conductive layers (conductive layers functioning as pixel electrodes, common electrodes, etc.) of light-emitting elements and light-receiving elements (or light-emitting / receiving elements).

[0359] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0360] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0361] (Embodiment 3) In this embodiment, a circuit that can be used in a display device of one embodiment of the present invention will be described.

[0362] FIG. 24A is a block diagram of a pixel of a display device of one embodiment of the present invention.

[0363] The pixel includes an OLED, an OPD (organic photo diode), a sensor circuit (referred to as a sensing circuit), a driving transistor (referred to as a driving transistor), and a selection transistor (referred to as a switching transistor).

[0364] Light emitted from the OLED is reflected by an object (hereinafter referred to as "Object"), and the reflected light is received by the OPD, thereby capturing an image of the object. One embodiment of the present invention can function as a touch sensor, an image sensor, an image scanner, etc. One embodiment of the present invention can be applied to biometric authentication by capturing an image of a fingerprint, palm print, blood vessels (veins, etc.), etc. It can also capture an image of a printed matter with photographs, text, etc., or the surface of an object, and acquire the image information.

[0365] The drive transistor and selection transistor constitute a drive circuit for driving the OLED. The drive transistor has the function of controlling the current flowing through the OLED, allowing the OLED to emit light at a brightness corresponding to that current. The selection transistor has the function of controlling the selection and non-selection of pixels. The value (e.g., voltage value) of video data (referred to as Video Data) input from outside via the selection transistor controls the magnitude of the current flowing through the drive transistor and OLED, allowing the OLED to emit light at the desired brightness.

[0366] The sensor circuit corresponds to a drive circuit for controlling the operation of the OPD, and can control operations such as a reset operation that resets the potential of the OPD electrodes, an exposure operation that accumulates charge in the OPD according to the amount of light irradiated, a transfer operation that transfers the charge accumulated in the OPD to a node in the sensor circuit, and a readout operation that outputs a signal (e.g., voltage or current) according to the magnitude of the charge to an external readout circuit as sensing data (referred to as "Sensing Data").

[0367] The pixel shown in FIG. 24B differs from the above mainly in that it has a memory section connected to the drive transistor.

[0368] Weight data is provided to the memory unit. Data obtained by adding together the video data input via the selection transistor and the weight data stored in the memory unit is provided to the drive transistor. The weight data stored in the memory unit can change the brightness of the OLED from the brightness when only video data is provided. Specifically, it is possible to increase or decrease the brightness of the OLED. For example, increasing the brightness of the OLED can increase the light receiving sensitivity of the sensor.

[0369] FIG. 24C shows an example of a pixel circuit that can be used in the sensor circuit.

[0370] 24C includes a light receiving element PD, a transistor M1, a transistor M2, a transistor M3, a transistor M4, and a capacitor C1. Here, an example is shown in which a photodiode is used as the light receiving element PD.

[0371] The cathode of the light-receiving element PD is electrically connected to the wiring V1, and the anode is electrically connected to one of the source and drain of the transistor M1. The gate of the transistor M1 is electrically connected to the wiring TX, and the other of the source and drain is electrically connected to one electrode of the capacitor C1, one of the source and drain of the transistor M2, and the gate of the transistor M3. The gate of the transistor M2 is electrically connected to the wiring RES, and the other of the source and drain is electrically connected to the wiring V2. The source and drain of the transistor M3 is electrically connected to the wiring V3, and the other of the source and drain is electrically connected to one of the source and drain of the transistor M4. The gate of the transistor M4 is electrically connected to the wiring SE, and the other of the source and drain is electrically connected to the wiring OUT1.

[0372] A constant potential is supplied to the wiring V1, wiring V2, and wiring V3. When the light-receiving element PD is driven with a reverse bias, a potential lower than the potential of the wiring V1 is supplied to the wiring V2. The transistor M2 is controlled by a signal supplied to the wiring RES and has the function of resetting the potential of the node connected to the gate of the transistor M3 to the potential supplied to the wiring V2. The transistor M1 is controlled by a signal supplied to the wiring TX and has the function of controlling the timing of transferring the charge accumulated in the light-receiving element PD to the node. The transistor M3 functions as an amplifying transistor that outputs according to the potential of the node. The transistor M4 is controlled by a signal supplied to the wiring SE and functions as a selection transistor that reads out the output according to the potential of the node to an external circuit connected to the wiring OUT1.

[0373] Here, the light receiving element PD corresponds to the OPD, and the potential or current output from the wiring OUT1 corresponds to the sensing data.

[0374] FIG. 24D shows an example of a pixel circuit for driving the OLED.

[0375] 24D includes a light-emitting element EL, transistors M5, M6, and M7, and a capacitor C2. Here, an example is shown in which a light-emitting diode is used as the light-emitting element EL. In particular, it is preferable to use an organic EL element as the light-emitting element EL.

[0376] The light-emitting element EL corresponds to the OLED, the transistor M5 corresponds to the selection transistor, the transistor M6 corresponds to the drive transistor, and the wiring VS corresponds to the wiring to which the video data is input.

[0377] The transistor M5 has a gate electrically connected to the wiring VG, one of its source and drain electrically connected to the wiring VS, and the other of its source and drain electrically connected to one electrode of the capacitor C2 and the gate of the transistor M6. One of the source and drain of the transistor M6 is electrically connected to the wiring V4, and the other is electrically connected to the anode of the light-emitting element EL and one of the source and drain of the transistor M7. The transistor M7 has a gate electrically connected to the wiring MS, and the other of its source and drain electrically connected to the wiring OUT2. The cathode of the light-emitting element EL is electrically connected to the wiring V5.

[0378] A constant potential is supplied to the wiring V4 and the wiring V5. The anode side of the light-emitting element EL can be set to a high potential, and the cathode side can be set to a lower potential than the anode side. The transistor M5 is controlled by a signal supplied to the wiring VG and functions as a selection transistor for controlling the selection state of the pixel circuit PIX2. The transistor M6 also functions as a drive transistor for controlling the current flowing through the light-emitting element EL according to the potential supplied to its gate. When the transistor M5 is in a conductive state, the potential supplied to the wiring VS is supplied to the gate of the transistor M6, and the light emission brightness of the light-emitting element EL can be controlled according to the potential. The transistor M7 is controlled by a signal supplied to the wiring MS and has one or both of the following functions: setting the potential between the transistor M6 and the light-emitting element EL to the potential supplied to the wiring OUT2, and outputting the potential between the transistor M6 and the light-emitting element EL to the outside via the wiring OUT2.

[0379] FIG. 24E shows an example of a pixel circuit including a memory unit that can be applied to the configuration shown in FIG. 24B.

[0380] 24E has a configuration in which a transistor M8 and a capacitor C3 are added to the pixel circuit PIX2. In addition, in the pixel circuit PIX3, the line VS in the pixel circuit PIX2 is changed to a line VS1, and the line VG is changed to a line VG1.

[0381] The transistor M8 has a gate electrically connected to the wiring VG2, one of a source and a drain electrically connected to the wiring VS2, and the other electrically connected to one electrode of the capacitor C3. The other electrode of the capacitor C3 is electrically connected to the gate of the transistor M6, one electrode of the capacitor C2, and the other of the source and drain of the transistor M5.

[0382] The wiring VS1 corresponds to the wiring to which the video data is supplied. The wiring VS2 corresponds to the wiring to which the weight data is supplied. The node to which the gate of the transistor M6 is connected corresponds to the memory unit.

[0383] An example of the operation method of the pixel circuit PIX3 will be described. First, a first potential is written from the wiring VS1 to a node connected to the gate of the transistor M6 via the transistor M5. Then, the transistor M5 is turned off, bringing the node into a floating state. Next, a second potential is written from the wiring VS2 to one electrode of the capacitor C3 via the transistor M8. As a result, the potential of the node changes from the first potential to a third potential in response to the second potential due to capacitive coupling of the capacitor C3. Then, a current corresponding to the third potential flows through the transistor M6 and the light-emitting element EL, causing the light-emitting element EL to emit light at a luminance corresponding to the third potential.

[0384] In the display device of this embodiment, an image may be displayed by causing the light-emitting element to emit light in a pulsed manner. By shortening the driving time of the light-emitting element, it is possible to reduce the power consumption of the display panel and suppress heat generation. In particular, organic EL elements are suitable because of their excellent frequency characteristics. The frequency can be, for example, 1 kHz or more and 100 MHz or less. Also, a driving method (also called duty driving) in which light is emitted by changing the pulse width may be used.

[0385] Here, it is preferable to use transistors that use a metal oxide (oxide semiconductor) in the semiconductor layer in which the channel is formed for the transistors M1, M2, M3, and M4 of the pixel circuit PIX1, the transistors M5, M6, and M7 of the pixel circuit PIX2, and the transistor M8 of the pixel circuit PIX3.

[0386] Alternatively, the transistors M1 to M8 may be transistors in which silicon is used as a semiconductor in which a channel is formed. In particular, using silicon with high crystallinity, such as single crystal silicon or polycrystalline silicon, is preferable because high field-effect mobility can be achieved and higher-speed operation can be achieved.

[0387] Alternatively, a structure may be used in which at least one of the transistors M1 to M8 includes an oxide semiconductor and the remaining transistors include silicon.

[0388] For example, transistors including an oxide semiconductor and having extremely low off-state current are preferably used as the transistors M1, M2, M5, M7, and M8, which function as switches for retaining charge. In this case, a transistor including silicon may be used as one or more of the other transistors.

[0389] Although the transistors in the pixel circuits PIX1, PIX2, and PIX3 are represented as n-channel transistors, p-channel transistors may also be used, or a configuration in which n-channel transistors and p-channel transistors are mixed may be used.

[0390] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0391] (Fourth embodiment) In this embodiment, a metal oxide (also referred to as an oxide semiconductor) that can be used for the transistor described in the above embodiment will be described.

[0392] The metal oxide preferably contains at least indium or zinc. It is particularly preferable that it contains indium and zinc. It is also preferable that it contains aluminum, gallium, yttrium, tin, or the like in addition to these. It may also contain one or more elements selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, and the like.

[0393] Furthermore, metal oxides can be formed by sputtering, chemical vapor deposition (CVD) such as metal organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), or the like.

[0394] <Classification of crystal structures> Examples of the crystalline structure of oxide semiconductors include amorphous (including completely amorphous), c-axis-aligned crystalline (CAAC), nanocrystalline (nc), cloud-aligned composite (CAC), single crystal, and polycrystal.

[0395] The crystalline structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectra. For example, it can be evaluated using XRD spectra obtained by GIXD (Grazing-Incidence XRD) measurements. The GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0396] For example, for a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, for an IGZO film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical peak shape of the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0397] The crystalline structure of a film or substrate can also be evaluated by the diffraction pattern (also called the nanobeam electron diffraction pattern) observed using nanobeam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. Furthermore, a spot-like pattern is observed in the diffraction pattern of an IGZO film deposited at room temperature, rather than a halo. For this reason, it is estimated that an IGZO film deposited at room temperature is neither crystalline nor amorphous, but is in an intermediate state, and it cannot be concluded that it is in an amorphous state.

[0398] <<Structure of oxide semiconductor>> Note that oxide semiconductors may be classified differently from the above when focusing on their structures. For example, oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0399] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0400] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction can be the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. If the atomic arrangement is considered as a lattice arrangement, a crystalline region can also be a region with a uniform lattice arrangement. Furthermore, CAAC-OS has a region where multiple crystalline regions are connected in the ab-plane direction, and the region may have distortion. Note that distortion refers to a location where the lattice arrangement changes between a region with a uniform lattice arrangement and a region with a different uniform lattice arrangement in the region where multiple crystalline regions are connected. In other words, CAAC-OS is an oxide semiconductor with a c-axis aligned but no clear orientation in the ab-plane direction.

[0401] Each of the multiple crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be several tens of nm.

[0402] In an In-M-Zn oxide (wherein M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), the CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter referred to as an In layer) and a layer containing M, zinc (Zn), and oxygen (hereinafter referred to as an (M, Zn) layer) are stacked. Note that indium and the element M are mutually substituted. Therefore, the (M, Zn) layer may contain indium. The In layer may contain M. The In layer may contain Zn. The layered structure is observed as a lattice image in a high-resolution transmission electron microscope (TEM) image, for example.

[0403] When the CAAC-OS film is subjected to structural analysis using, for example, an XRD apparatus, a peak indicating c-axis orientation is detected at or near 2θ=31° in out-of-plane XRD measurement using θ / 2θ scan. Note that the position of the peak indicating c-axis orientation (2θ value) may vary depending on the type and composition of the metallic elements constituting the CAAC-OS.

[0404] For example, in the electron diffraction pattern of a CAAC-OS film, multiple bright spots are observed, and the spots are observed at positions that are point-symmetric with respect to the spot of the incident electron beam that has passed through the sample (also called the direct spot).

[0405] When the crystalline region is observed from the specific direction, the lattice arrangement within the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the distortion may have a pentagonal, heptagonal, or other lattice arrangement. In the CAAC-OS, no clear grain boundaries are observed even near the distortion. This indicates that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of close-packed oxygen atom arrangement in the ab-plane direction and the change in interatomic bond distance caused by metal atom substitution.

[0406] A crystal structure with clear grain boundaries is called polycrystalline. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in the on-state current and field-effect mobility of a transistor. Therefore, CAAC-OS, which lacks clear grain boundaries, is one of the crystalline oxides with a crystal structure suitable for use in the semiconductor layer of a transistor. Zn is preferred for use in CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are suitable because they can suppress the generation of grain boundaries more effectively than In oxide.

[0407] CAAC-OS is an oxide semiconductor with high crystallinity and no clear grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to grain boundaries. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by the inclusion of impurities or the generation of defects, the CAAC-OS can also be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Therefore, oxide semiconductors with CAAC-OS have stable physical properties. Therefore, oxide semiconductors with CAAC-OS are heat-resistant and highly reliable. Furthermore, the CAAC-OS is stable even under high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using a CAAC-OS for an OS transistor can increase the flexibility of the manufacturing process.

[0408] [nc-OS] The nc-OS has periodic atomic arrangement in a microscopic region (e.g., a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has microcrystalline structures. The size of the microcrystalline structures is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore these microcrystalline structures are also called nanocrystalline structures. Furthermore, the nc-OS exhibits no regularity in the crystal orientation between different nanocrystalline structures. Therefore, the entire film lacks orientation. Therefore, depending on the analytical method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor. For example, when a structural analysis of an nc-OS film is performed using an XRD apparatus, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Furthermore, when an nc-OS film is subjected to electron diffraction (also known as selected-area electron diffraction) using an electron beam with a probe diameter larger than that of nanocrystalline structures (e.g., 50 nm or larger), a halo-like diffraction pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystals (for example, 1 nm to 30 nm), an electron diffraction pattern can be obtained in which multiple spots are observed within a ring-shaped region centered on the direct spot.

[0409] [a-like OS] The a-like OS is an oxide semiconductor having a structure between the nc-OS and the amorphous oxide semiconductor. The a-like OS has a pore or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. Furthermore, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and CAAC-OS.

[0410] <<Oxide semiconductor structure>> Next, the above-mentioned CAC-OS will be described in detail, which relates to the material composition.

[0411] [CAC-OS] CAC-OS is a material structure in which elements constituting a metal oxide are unevenly distributed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or a similar size range. Hereinafter, a metal oxide in which one or more metal elements are unevenly distributed and the regions containing the metal elements are mixed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or a similar size range, is also referred to as a mosaic or patch state.

[0412] Furthermore, CAC-OS has a mosaic structure in which the material is separated into first and second regions, and the first regions are distributed throughout the film (hereinafter also referred to as a cloud structure). That is, CAC-OS is a composite metal oxide having a structure in which the first and second regions are mixed.

[0413] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In-Ga-Zn oxide, the first region is a region where [In] is larger than [In] in the composition of the CAC-OS film. The second region is a region where [Ga] is larger than [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0414] Specifically, the first region is a region whose main component is indium oxide, indium zinc oxide, or the like. The second region is a region whose main component is gallium oxide, gallium zinc oxide, or the like. In other words, the first region can be rephrased as a region whose main component is In. The second region can be rephrased as a region whose main component is Ga.

[0415] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0416] In addition, CAC-OS in In-Ga-Zn oxide refers to a material structure containing In, Ga, Zn, and O, in which some regions primarily composed of Ga and other regions primarily composed of In are randomly arranged in a mosaic pattern. Therefore, it is presumed that CAC-OS has a structure in which metal elements are distributed nonuniformly.

[0417] The CAC-OS can be formed, for example, by a sputtering method without heating the substrate. When the CAC-OS is formed by a sputtering method, one or more of an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. The lower the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition, the better. For example, the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition is preferably 0% or more and less than 30%, and more preferably 0% or more and 10% or less.

[0418] Furthermore, for example, in the case of CAC-OS in an In-Ga-Zn oxide, EDX mapping obtained using EDX (Energy Dispersive X-ray spectroscopy) confirms that the CAC-OS has a structure in which a region containing In as a main component (first region) and a region containing Ga as a main component (second region) are unevenly distributed and mixed.

[0419] Here, the first region has higher conductivity than the second region. That is, the flow of carriers through the first region causes the metal oxide to exhibit conductivity. Therefore, the first region is distributed in a cloud-like manner in the metal oxide, thereby achieving a high field-effect mobility (μ).

[0420] On the other hand, the second region has higher insulating properties than the first region. That is, the second region is distributed in the metal oxide, thereby suppressing leakage current.

[0421] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act complementarily, thereby providing the CAC-OS with a switching function (the ability to turn on and off). In other words, CAC-OS has a conductive function in part of the material and an insulating function in part of the material, and the material as a whole functions as a semiconductor. By separating the conductive function from the insulating function, both functions can be maximized. Therefore, by using CAC-OS in a transistor, a high on-current (I on ), high field-effect mobility (μ), and good switching behavior can be achieved.

[0422] Furthermore, a transistor using CAC-OS has high reliability, making it ideal for various semiconductor devices such as display devices.

[0423] Oxide semiconductors have a variety of structures, each with different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS.

[0424] <Transistors containing oxide semiconductors> Next, a case where the oxide semiconductor is used in a transistor will be described.

[0425] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0426] For the transistor, an oxide semiconductor with a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 Less than 1 × 10 15 cm -3 or less, more preferably 1 × 10 13 cm -3Less than or equal to 1×10 11 cm -3 or less, more preferably 1 × 10 10 cm -3 Less than 1 x 10 -9 cm -3 That is all. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, a semiconductor having a low impurity concentration and a low density of defect states is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may also be referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor.

[0427] Furthermore, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore the density of trap states may also be low.

[0428] Furthermore, charges trapped in the trap states of an oxide semiconductor take a long time to disappear and may behave like fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0429] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in the adjacent film. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon.

[0430] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0431] When an oxide semiconductor contains silicon or carbon, which is one of the Group 14 elements, defect levels are formed in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are calculated to be 2×10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0432] Furthermore, when an oxide semiconductor contains an alkali metal or alkaline earth metal, defect levels may be formed and carriers may be generated. Therefore, a transistor using an oxide semiconductor containing an alkali metal or alkaline earth metal is likely to have normally-on characteristics. Therefore, when the concentration of the alkali metal or alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 18 atoms / cm 3 Less than or equal to 2 x 10 16 atoms / cm 3 Do the following:

[0433] Furthermore, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in the oxide semiconductor obtained by SIMS is set to 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than 1×10, more preferably 18 atoms / cm 3 Less than 5 × 10, more preferably 17 atoms / cm 3 Do the following:

[0434] Furthermore, hydrogen contained in an oxide semiconductor may react with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. When hydrogen enters the oxygen vacancy, electrons serving as carriers may be generated. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons serving as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. For this reason, it is preferable to reduce the amount of hydrogen in the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in an oxide semiconductor measured by SIMS is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5 × 10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 Make it less than.

[0435] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0436] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0437] (Embodiment 5) In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0438] An electronic device of one embodiment of the present invention can capture an image with a display portion, detect a touch operation, etc. This can improve the functionality and convenience of the electronic device.

[0439] Examples of electronic devices according to one embodiment of the present invention include electronic devices with relatively large screens, such as television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproduction devices.

[0440] An electronic device according to one embodiment of the present invention may have a sensor (including a function for measuring force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0441] The electronic device of one embodiment of the present invention can have various functions, such as a function to display various information (still images, videos, text images, etc.) on a display portion, a touch panel function, a function to display a calendar, date, time, etc., a function to execute various software (programs), a wireless communication function, a function to read programs or data recorded on a recording medium, etc.

[0442] Electronic device 6500 shown in FIG. 25A is a portable information terminal that can be used as a smartphone.

[0443] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508. The display portion 6502 has a touch panel function.

[0444] The display device described in Embodiment 1 or 2 can be applied to the display portion 6502.

[0445] FIG. 25B is a schematic cross-sectional view including the end of the housing 6501 on the microphone 6506 side.

[0446] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0447] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by adhesive layers (not shown).

[0448] In an area outside the display unit 6502, a part of the display panel 6511 is folded back, and an FPC 6515 is connected to the folded back part. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0449] The flexible display of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while keeping the thickness of the electronic device small. Furthermore, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0450] By using the display device described in Embodiment 1 or 2 for the display panel 6511, an image can be captured in the display portion 6502. For example, a fingerprint can be captured on the display panel 6511 for fingerprint authentication.

[0451] The display portion 6502 further includes a touch sensor panel 6513, which allows the display portion 6502 to have a touch panel function. The touch sensor panel 6513 can be of any of various types, such as a capacitive type, a resistive type, a surface acoustic wave type, an infrared type, an optical type, or a pressure-sensitive type. Alternatively, the display panel 6511 may function as a touch sensor, in which case the touch sensor panel 6513 is not necessarily provided.

[0452] 26A shows an example of a television device. A television device 7100 has a display unit 7000 built into a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0453] The display device described in Embodiment 1 or 2 can be applied to the display portion 7000.

[0454] 26A can be operated using an operation switch provided on the housing 7101 or a separate remote control 7111. Alternatively, a touch sensor may be provided in the display unit 7000, and the television 7100 may be operated by touching the display unit 7000 with a finger or the like. The remote control 7111 may have a display unit that displays information output from the remote control 7111. The channel and volume can be controlled using the operation keys or touch panel provided on the remote control 7111, and the video displayed on the display unit 7000 can be controlled.

[0455] The television device 7100 is configured to include a receiver, a modem, and the like. The receiver can receive general television broadcasts. In addition, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0456] 26B shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. A display portion 7000 is incorporated in the housing 7211.

[0457] The display device described in Embodiment 1 or 2 can be applied to the display portion 7000.

[0458] 26C and 26D show an example of digital signage.

[0459] 26C includes a housing 7301, a display unit 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0460] 26D shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0461] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it will attract people's attention, which can increase the advertising effectiveness of, for example, advertisements.

[0462] Applying a touch panel to the display unit 7000 is preferable because it not only displays images or videos on the display unit 7000 but also allows the user to intuitively operate it. Furthermore, when used to provide information such as route information or traffic information, intuitive operation can improve usability.

[0463] 26C and 26D, it is preferable that digital signage 7300 or digital signage 7400 can wirelessly link with information terminal 7311 or information terminal 7411, such as a smartphone carried by a user. For example, advertising information displayed on display unit 7000 can be displayed on the screen of information terminal 7311 or information terminal 7411. Furthermore, by operating information terminal 7311 or information terminal 7411, the display on display unit 7000 can be switched.

[0464] 26C and 26D, the display device described in Embodiment Mode 1 or 2 can be applied to the display portion of the information terminal 7311 or the information terminal 7411.

[0465] Furthermore, it is also possible to run a game on the digital signage 7300 or the digital signage 7400 using the screen of the information terminal 7311 or the information terminal 7411 as an operation means (controller), thereby allowing an unspecified number of users to simultaneously participate in and enjoy the game.

[0466] The electronic device shown in Figures 27A to 27F has a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including the function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 9008, etc.

[0467] The electronic devices shown in Figures 27A to 27F have various functions. For example, they may have a function to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date, or time, a function to control processing using various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. Note that the functions of the electronic devices are not limited to these, and they may have various other functions. The electronic devices may have multiple display units. Furthermore, the electronic devices may be provided with a camera or the like, and may have a function to capture still images or videos and store them on a recording medium (external or built-in to the camera), a function to display the captured images on the display unit, etc.

[0468] The electronic devices shown in FIGS. 27A to 27F will be described in detail below.

[0469] FIG. 27A is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 can be used as, for example, a smartphone. The mobile information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, and the like. The mobile information terminal 9101 can display text, image information, and the like on multiple surfaces thereof. FIG. 27A shows an example in which three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the title of the email or SNS message, the sender's name, the date and time, the remaining battery level, and the strength of antenna reception. Alternatively, the icon 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0470] 27B is a perspective view showing mobile information terminal 9102. Mobile information terminal 9102 has a function of displaying information on three or more sides of display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, while carrying mobile information terminal 9102 in a breast pocket of clothes, the user can check information 9053 displayed in a position that can be observed from above mobile information terminal 9102. The user can check the display without taking mobile information terminal 9102 out of their pocket and decide, for example, whether to answer a call.

[0471] 27C is a perspective view showing a wristwatch-type mobile information terminal 9200. The display surface of the display unit 9001 is curved, and a display can be displayed along the curved display surface. The mobile information terminal 9200 can also perform hands-free conversations by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and reception with other information terminals or charge itself via a connection terminal 9006. Charging may be performed by wireless power supply.

[0472] 27D to 27F are perspective views showing a foldable mobile information terminal 9201. FIG. 27D shows the mobile information terminal 9201 in an unfolded state, FIG. 27F shows it in a folded state, and FIG. 27E is a perspective view showing a state in the process of changing from one of FIG. 27D and FIG. 27F to the other. The mobile information terminal 9201 is highly portable when folded, and has a seamless, wide display area when unfolded, allowing for excellent display visibility. The display unit 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a curvature radius of 0.1 mm or more and 150 mm or less.

[0473] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification. [Explanation of symbols]

[0474] 10A, 10B, 110A, 110B, 110C, 110D, 110E, 110F, 110G, 110H, 110J, 110K, 110L, 110M, 11 0N, 110P, 110Q, 110R, 110S, 110T, 110U, 110W: Display device, 11, 12: Substrate, 13: Insulating layer, 14: Partition wall, 20: Photodetector element, 21: light-receiving layer, 30: light-emitting element, 31: light-emitting layer, 40, 40a, 40b, 40X, 40Y: conductive layer, 41, 42: pixel electrode, 50, 50X, 50Y: wiring, 51, 52: transistor, 55: connection portion, 60: common electrode, 61, 62: common layer, 63: protective layer, 80, 90: light, 120: display portion, 121: non-display portion

Claims

[Claim 1] a light receiving element, a light emitting element, a conductive layer, and a first wiring; the light receiving element has a first pixel electrode, a common layer on the first pixel electrode, an active layer on the common layer, and a common electrode on the active layer; the light-emitting element has a second pixel electrode, the common layer on the second pixel electrode, a light-emitting layer on the common layer, and the common electrode on the light-emitting layer; the conductive layer is provided on the same surface as the first pixel electrode and the second pixel electrode, is located between the first pixel electrode and the second pixel electrode, is electrically connected to the common layer, and is electrically connected to the first wiring to which a first potential is applied; the common layer has a portion overlapping the first pixel electrode, a portion overlapping the second pixel electrode, and a portion overlapping the conductive layer; the common electrode has a portion overlapping the first pixel electrode and a portion overlapping the second pixel electrode; The display device, wherein the first wiring is provided on a surface different from the conductive layer.

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