Indication device

Abstract

To provide a display device with an imaging function, and provide a high-definition imaging device or display device.SOLUTION: A display device has first to third switches, first and second transistors, a capacitor, first and second wires, and a light-receiving element. The first switch has one electrode electrically connected to the first wire and the other electrode electrically connected to a gate of the first transistor and one electrode of the capacitor. The second switch has one electrode electrically connected to one of a source and a drain of the first transistor, one electrode of the light-receiving element, and the other electrode of the capacitor, and has the other electrode electrically connected to a gate of the second transistor and one electrode of the third switch. The third switch has the other electrode electrically connected to the second wire. The light-receiving element has a function of emitting light with a first color and a function of receiving light with a second color.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] FIELD OF THE INVENTION One embodiment of the present invention relates to a display device having an imaging function.

[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, 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 required to have higher resolution in order to display high-resolution images. Furthermore, for information terminal devices such as smartphones, tablet devices, and notebook PCs (personal computers), display devices are required to have not only high resolution but also low power consumption. Furthermore, there is a demand for display devices that not only display images but also have various additional functions, such as touch panel functionality and the ability to capture fingerprints for authentication.

[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 an imaging function.An object of one embodiment of the present invention is to provide an imaging device or a display device having a high-definition display portion or an imaging portion.An object of one embodiment of the present invention is to provide an imaging device or a display device that can capture high-definition images.An object of one embodiment of the present invention is to provide an imaging device or a display device that can capture images with high sensitivity.An object of one embodiment of the present invention is to provide a display device that can acquire biometric information such as a fingerprint.An object of one embodiment of the present invention is to provide a display device that functions as a touch panel.

[0007] Another object of one embodiment of the present invention is to reduce the number of components in an electronic device.Another object of one embodiment of the present invention is to provide a display device, an imaging device, an electronic device, or the like having a novel structure.Another object of one embodiment of the present invention is to alleviate at least one of the problems of the prior art.

[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 first to third switches, a first transistor, a second transistor, a capacitor, a first wiring, a second wiring, and a light-emitting / receiving element. One electrode of the first switch is electrically connected to the first wiring, and the other electrode is electrically connected to a gate of the first transistor and one electrode of the capacitor. One electrode of the second switch is electrically connected to one of the source and drain of the first transistor, one electrode of the light-emitting / receiving element, and the other electrode of the capacitor, and the other electrode is electrically connected to a gate of the second transistor and one electrode of the third switch. The other electrode of the third switch is electrically connected to the second wiring. The light-emitting / receiving element has a function of emitting light of a first color and a function of receiving light of a second color.

[0010] In the above, it is preferable that during the first period, the first switch, the second switch, and the third switch are in a conductive state, a data potential is applied to the first wiring, and a first potential is applied to the second wiring. Furthermore, during the second period, it is preferable that the second switch and the third switch are in a conductive state, and a second potential is applied to the second wiring. Furthermore, it is preferable that the second potential is lower than the first potential.

[0011] In the above, it is preferable that the semiconductor device further includes a fourth switch. In this case, it is preferable that one electrode of the fourth switch is electrically connected to one electrode of the second switch and the other electrode is electrically connected to one electrode of the light emitting / receiving element. Alternatively, it is preferable that one electrode of the fourth switch is electrically connected to one of the source and drain of the first transistor and the other electrode is electrically connected to one electrode of the light emitting / receiving element.

[0012] Another embodiment of the present invention is a display device including first to sixth transistors, a capacitor, a light-emitting / receiving element, a first wiring, and a second wiring. One of a source and a drain of the first transistor is electrically connected to one electrode of the light-emitting / receiving element. One of a source and a drain of the third transistor is electrically connected to the first wiring and the other of the source and drain is electrically connected to the gate of the first transistor. One of a source and a drain of the fourth transistor is electrically connected to the gate of the second transistor and the other of the source and drain is electrically connected to the second wiring. One of a source and a drain of the fifth transistor is electrically connected to one of the source and drain of the second transistor. One of a source and a drain of the sixth transistor is electrically connected to one electrode of the light-emitting / receiving element and the other is electrically connected to the gate of the second transistor. One electrode of the capacitor is electrically connected to the gate of the first transistor and the other electrode is electrically connected to one of the source and drain of the first transistor. The light emitting / receiving element has a function of emitting light of a first color and a function of receiving light of a second color.

[0013] In the above, it is preferable that a seventh transistor be further included. In this case, it is preferable that the seventh transistor has a function of controlling conduction between one of a source and a drain of the first transistor and one electrode of the light emitting / receiving element.

[0014] Another embodiment of the present invention is a display device including first to fifth transistors, an eighth transistor, a capacitor, a light-emitting / receiving element, a first wiring, and a second wiring. One of a source and a drain of the first transistor is electrically connected to one of a source and a drain of the eighth transistor and a gate of the second transistor. One of a source and a drain of the third transistor is electrically connected to the first wiring and the other of the source and drain is electrically connected to the gate of the first transistor. One of a source and a drain of the fourth transistor is electrically connected to the gate of the second transistor and the other of the source and drain is electrically connected to the second wiring. One of a source and a drain of the fifth transistor is electrically connected to one of a source and a drain of the second transistor. The other of the source and drain of the eighth transistor is electrically connected to one electrode of the light-emitting / receiving element. One electrode of the capacitor is electrically connected to the gate of the first transistor and the other electrode is electrically connected to one of a source and a drain of the first transistor. The light emitting / receiving element has a function of emitting light of a first color and a function of receiving light of a second color.

[0015] In any of the above, it is preferable that the fifth transistor further includes a third wiring, and in this case, the other of the source and the drain of the fifth transistor is preferably electrically connected to the third wiring.

[0016] Alternatively, in any of the above, the other of the source and the drain of the fifth transistor is preferably electrically connected to the first wiring.

[0017] In any of the above, it is preferable that during the first period, a data potential is applied to the first wiring and a first potential is applied to the second wiring. Also, during the second period, it is preferable that a second potential is applied to the second wiring. In this case, it is preferable that the second potential is lower than the first potential.

[0018] In any of the above, it is preferable that the device further comprises a light-emitting element. In this case, it is preferable that the light-emitting element has a function of emitting light of a second color. Furthermore, it is preferable that the light-emitting / receiving element and the light-emitting element are provided on the same surface.

[0019] In the above, it is preferable that the light emitting / receiving element has a first pixel electrode, a first light emitting layer, an active layer, and a first electrode, and the light emitting element has a second pixel electrode, a second light emitting layer, and a first electrode. Furthermore, it is preferable that the first pixel electrode and the second pixel electrode are formed by processing the same conductive film.

[0020] Another embodiment of the present invention is a display module including any one of the display devices described above and a connector or an integrated circuit.

[0021] Another embodiment of the present invention is an electronic device including the above-described display module and at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, a touch sensor, and an operation button. [Effects of the Invention]

[0022] According to one embodiment of the present invention, a display device having an imaging function can be provided. Alternatively, an imaging device or display device having a high-definition display portion or imaging portion can be provided. Alternatively, an imaging device or display device capable of capturing high-definition images can be provided. Alternatively, an imaging device or display device capable of capturing high-sensitivity images can be provided. Alternatively, a display device capable of acquiring biometric information such as a fingerprint can be provided. Alternatively, a display device functioning as a touch panel can be provided.

[0023] According to one aspect of the present invention, the number of components in an electronic device can be reduced, or a display device, an imaging device, or an electronic device having a novel configuration can be provided, or at least one of the problems of the prior art can be alleviated.

[0024] 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]

[0025] [Figure 1] FIG. 1 is a circuit diagram showing an example of a pixel. [Figure 2] 2A and 2B are diagrams illustrating an example of a method for operating a pixel circuit. [Figure 3] 3A to 3C are diagrams illustrating an example of a method for operating a pixel circuit. [Figure 4] 4A to 4C are circuit diagrams showing examples of pixel circuits. [Figure 5] FIG. 5 is a diagram illustrating an example of a display device. [Figure 6] FIG. 6 is a circuit diagram showing an example of a pixel. [Figure 7] FIG. 7A is a circuit diagram showing an example of a pixel, and FIG. 7B is a circuit diagram of a transistor. [Figure 8] 8A and 8B are circuit diagrams showing an example of a pixel. [Figure 9] 9A and 9B are circuit diagrams showing an example of a pixel. [Figure 10] 10A and 10B are diagrams showing an example of a display device. [Figure 11] FIG. 11 is a circuit diagram showing an example of a pixel. [Figure 12] FIG. 12 is a diagram illustrating an example of a method of operating the display device. [Figure 13] FIG. 13 is a diagram illustrating an example of a method of operating the display device. [Figure 14] 14A and 14B are circuit diagrams showing an example of a pixel. [Figure 15] FIG. 15 is a circuit diagram showing an example of a pixel. [Figure 16] FIG. 16 is a circuit diagram showing an example of a pixel. [Figure 17] FIG. 17 is a diagram illustrating an example of a method of operating the display device. [Figure 18] 18A to 18D are cross-sectional views showing an example of a display device, and Fig. 18E to 18G are top views showing an example of a pixel. [Figure 19] 19A to 19D are top views showing examples of pixels. [Figure 20] 20A to 20E are cross-sectional views showing examples of light emitting and receiving elements. [Figure 21] 21A and 21B are cross-sectional views showing an example of a display device. [Figure 22] 22A and 22B are cross-sectional views showing an example of a display device. [Figure 23] 23A and 23B are cross-sectional views showing an example of a display device. [Figure 24] 24A and 24B are cross-sectional views showing an example of a display device. [Figure 25] 25A and 25B are cross-sectional views showing an example of a display device. [Figure 26] FIG. 26 is a perspective view showing an example of a display device. [Figure 27] FIG. 27 is a cross-sectional view showing an example of a display device. [Figure 28] FIG. 28 is a cross-sectional view showing an example of a display device. [Figure 29] 29A is a cross-sectional view showing an example of a display device, and FIG 29B is a cross-sectional view showing an example of a transistor. [Figure 30] 30A and 30B are diagrams showing an example of an electronic device. [Figure 31] 31A to 31D are diagrams showing examples of electronic devices. [Figure 32] 32A to 32F are diagrams showing examples of electronic devices. DETAILED DESCRIPTION OF THE INVENTION

[0026] 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.

[0027] 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.

[0028] 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.

[0029] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components and do not limit the number.

[0030] A transistor is a type of semiconductor element that can perform switching operations such as amplifying current or voltage and controlling conduction or non-conduction. In this specification, the term "transistor" includes an IGFET (Insulated Gate Field Effect Transistor) and a TFT (Thin Film Transistor).

[0031] Furthermore, the functions of "source" and "drain" may be interchangeable when transistors of different polarities are used, or when the direction of current flow changes during circuit operation, etc. For this reason, the terms "source" and "drain" may be used interchangeably in this specification.

[0032] Furthermore, in this specification, "electrically connected" includes connection via "something that has some kind of electrical action." Here, "something that has some kind of electrical action" is not particularly limited as long as it allows electrical signals to be transmitted and received between the connected objects. For example, "something that has some kind of electrical action" includes electrodes, wiring, switching elements such as transistors, resistive elements, coils, capacitive elements, and other elements with various functions.

[0033] In this specification, a node refers to an element (for example, a wiring) that allows electrical connection of elements that make up a circuit. Therefore, a "node to which A is connected" refers to a wiring that is electrically connected to A and can be considered to have the same potential as A. Even if one or more elements (for example, a switch, transistor, capacitance element, inductor, resistance element, diode, etc.) that allow electrical connection are placed along the wiring, the wiring is considered to be a node to which A is connected as long as it can be considered to have the same potential as A.

[0034] In this specification, the EL layer refers to a layer provided between a pair of electrodes of a light-emitting element and containing at least a light-emitting substance (also referred to as a light-emitting layer), or a stack including a light-emitting layer.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] (Embodiment 1) In this embodiment, a structural example of a display device according to one embodiment of the present invention and an example of a driving method thereof will be described.

[0041] One embodiment of the present invention is a display device having a plurality of pixels arranged in a matrix, each of which has one or more sub-pixels, and each of which has one or more light-emitting and light-emitting elements.

[0042] A light-emitting / receiving element (light-emitting / receiving device) is an element that has both the function of a light-emitting element (also called a light-emitting device) that emits light of a first color and the function of a photoelectric conversion element (also called a photoelectric conversion device) that receives light of a second color. A light-emitting / receiving element can also be called a multifunctional element, multifunctional diode, light-emitting photodiode, bidirectional photodiode, etc.

[0043] By arranging a plurality of sub-pixels, each having a light receiving / emitting element, in a matrix, the display device can have both the function of displaying an image and the function of capturing an image, and therefore the display device can also be called a composite device or a multi-function device.

[0044] [Configuration example 1] [Configuration Example 1-1] 1 shows a portion of a pixel circuit that can be applied to a subpixel having a light-emitting / receiving element. The pixel circuit includes switches SW1, SW2, and SW3, transistors Tr1 and Tr2, and a light-emitting / receiving element SA. The pixel circuit preferably also includes capacitors CS1 and CS2 for holding electric charges. The pixel circuit is also connected to wirings SL, VL1, AL, CL, VCP, VPI, and WX.

[0045] The switches SW1, SW2, and SW3 each have two terminals (electrodes) and are elements that can control the conduction and non-conduction between the terminals.

[0046] One terminal of the switch SW1 is electrically connected to the wiring SL, and the other terminal is electrically connected to the gate of the transistor Tr1 and one electrode of the capacitor CS1. One of the source and drain of the transistor Tr1 is electrically connected to the wiring AL, and the other terminal is electrically connected to one terminal of the switch SW2, one electrode of the light emitting / receiving element SA, and the other electrode of the capacitor CS1. The other terminal of the switch SW2 is electrically connected to the gate of the transistor Tr2, one terminal of the switch SW3, and one electrode of the capacitor CS2. The other terminal of the switch SW3 is electrically connected to the wiring VL1. The other electrode of the capacitor CS2 is electrically connected to the wiring VCP. One of the source and drain of the transistor Tr2 is electrically connected to the wiring WX, and the other terminal is electrically connected to the wiring VPI. The other electrode of the light emitting / receiving element SA is electrically connected to the wiring CL.

[0047] It is preferable that a constant potential be applied to the wiring VCP and the wiring VPI. The constant potential may be a potential VDD, a potential VSS, a ground potential, a reference potential, a common potential, or the like.

[0048] 1, the anode of the light emitting element SA is located on the transistor Tr1 side. In this case, the potential applied to the wiring CL can be lower than the potential applied to the wiring AL. Note that the cathode of the light emitting element SA may be located on the transistor Tr1 side, in which case the potential applied to the wiring CL can be higher than the potential applied to the wiring AL.

[0049] 1 and the like show examples in which n-channel transistors are used as the transistors, p-channel transistors can also be used for some or all of the transistors, in which case various potentials, signals, and the like can be changed as appropriate depending on the type of transistor.

[0050] The transistor Tr1 has a function of controlling the current flowing through the light emitting / receiving element SA. That is, the transistor Tr1 functions as a drive transistor. The transistor Tr1 can control the current flowing through the light emitting / receiving element SA in accordance with the potential (data potential) applied from the line SL via the switch SW1. The light emitting / receiving element SA can emit light with a brightness corresponding to the current.

[0051] The conduction state of the transistor Tr2 changes in response to the charge (potential) transferred from the light emitting / receiving element SA to a node to which the gate is connected. The transistor Tr2 functions as a readout transistor. The wiring WX also functions as a readout wiring.

[0052] At least two types of potentials are applied to the wiring VL1. One is a potential V0, which is applied to the source of the transistor Tr1 when writing a data potential to the gate of the transistor Tr1. The other is a potential V RSand is a potential for resetting (initializing) the potential of the node to which the anode of the light emitting / receiving element SA is connected. In this way, by supplying two types of potentials through a single wiring VL1, the number of wirings can be reduced and the circuit configuration can be simplified. This makes it possible to reduce the area occupied by the pixel and realize a display device with high resolution. Therefore, not only can high-quality images be displayed, but also high-resolution images can be captured.

[0053] The operation method of the pixel circuit illustrated in FIG. 1 will now be described.

[0054] First, an example of an operation method when the light emitting / receiving element SA is used as a light emitting element will be described with reference to FIGS. 2A and 2B.

[0055] FIG. 2A shows a case where a data potential V data 10A and 10B show the operation during the data write period (data write period). During the data write period, the switches SW1, SW2, and SW3 are all in a conductive state.

[0056] During the data write period, as shown by one dashed arrow, the gate of the transistor Tr1 is supplied with a data potential V data As shown by the other dashed arrow, the other of the source and drain of the transistor Tr1 is supplied with a potential V0 from the wiring VL1 via the switches SW2 and SW3. At this time, the capacitor CS1 is supplied with a data potential V data The potential difference between V0 and V1 is charged.

[0057] FIG. 2B shows a schematic diagram of the operation during the period (holding and light-emitting periods) in which the gate potential of transistor Tr1 is maintained and the light-emitting element SA emits light in response to the current flowing through transistor Tr1. During the holding and light-emitting periods, switches SW1, SW2, and SW3 are all in a non-conducting state. This causes almost all of the current flowing through transistor Tr1 to flow to the light-emitting element SA. In FIG. 2B, the current path is indicated by dashed arrows.

[0058] Next, an example of an operation method when the light emitting / receiving element SA is used as a light receiving element will be described with reference to FIGS. 3A to 3C.

[0059] 3A schematically shows the operation during a period (reset period) in which the potential of the anode of the light emitting / receiving element SA is initialized. During the reset period, the switches SW1, SW2, and SW3 are all in a conductive state.

[0060] During the reset period, as shown by one of the dashed arrows, the anode of the light emitting element SA is supplied with a potential V RS is given. The potential V RS The potential V is at least lower than the potential applied to the wiring CL. RS is preferably set to a potential lower than the potential V0.

[0061] In addition, when the cathode of the light emitting element SA is connected to the transistor Tr1 side, the potential V RS The potential V may be set to a potential higher than the potential applied to the wiring CL (the potential applied to the anode of the light emitting element SA). RS can be a potential higher than the potential V0.

[0062] During the reset period, the gate of the transistor Tr1 is supplied with a potential V off is given. The potential V offis set to a potential that turns off the transistor Tr1. This prevents the anode potential of the light emitting element SA from unintentionally changing due to the current that flows from the wiring AL to the light emitting element SA via the transistor Tr1 in the subsequent period. For example, the potential V off is the potential V RS The potential V can be set to a potential lower than the potential obtained by adding the threshold voltage of the transistor Tr1 to the potential V off is the potential V RS It is preferable that the potential is lower than

[0063] 3B shows a schematic diagram of the operation during the period (exposure period) in which the light receiving / emitting element SA receives light and charge is accumulated in the light receiving / emitting element SA. During the exposure period, charge is accumulated across the light receiving / emitting element SA, causing a change in the potential difference Vc between the anode and cathode of the light receiving / emitting element SA.

[0064] During the exposure period, the switches SW1, SW2, and SW3 are all in a non-conductive state. At this time, the gate of the transistor Tr1 is supplied with the potential V off Therefore, as shown in the figure, no current flows through transistor Tr1. Therefore, the charge stored on the anode side of the light emitting / receiving element SA can be prevented from flowing out to transistors Tr1 and Tr2. As a result, highly accurate imaging can be achieved.

[0065] FIG. 3C shows a schematic diagram of the operation during the period (transfer period) in which the charge accumulated in the light emitting / receiving element SA is transferred to the node connected to the gate of transistor Tr2. During the transfer period, switch SW2 is turned on, and switches SW1 and SW3 are turned off. As a result, as indicated by the dashed arrow, the charge accumulated in the light emitting / receiving element SA is transferred via switch SW2 to the node connected to the gate of transistor Tr2. After the charge transfer is complete, switch SW2 is turned off, thereby maintaining the gate potential of transistor Tr2. At this time, a current I according to the gate potential of transistor Tr2 flows.S flows from wiring VPI to wiring WX.

[0066] In this way, by switching the potential applied to the wiring VL1 between the data writing period for display and the reset period for imaging, the number of wirings can be reduced and the pixel circuit can be simplified. This makes it easier to achieve higher definition and higher resolution in the display device. Furthermore, the reduction in the number of wirings also reduces the power consumption of the display device.

[0067] [Configuration Example 1-2] Figure 4A shows an example of a pixel circuit configuration different from that shown in Figure 1. Figure 4A differs mainly from the above in that it has a switch SW4.

[0068] The switch SW4 is provided between the light emitting / receiving element SA and the transistor Tr1, and can control the conduction / non-conduction thereof. In Fig. 4A, one terminal (electrode) of the switch SW4 is electrically connected to the other of the source and drain of the transistor Tr1, one terminal of the switch SW2, and the other electrode of the capacitor CS1.

[0069] By turning off the switch SW4, the light emitting element SA and the transistor Tr1 can be electrically isolated. Therefore, the current flowing to the light emitting element SA via the transistor Tr1 can be cut off regardless of the gate potential of the transistor Tr1. As a result, during the reset period exemplified above, the gate of the transistor Tr1 is supplied with a potential V off Since it is not necessary to provide the driving method, the driving method can be simplified.

[0070] Moreover, the switch SW4 may be provided at a position shown in Fig. 4B. Specifically, one terminal of the switch SW2 is electrically connected between the light emitting / receiving element SA and the switch SW4.

[0071] At this time, during the exposure period and the transfer period, the gate of the transistor Tr1 can be set to a state in which the data potential is held. As a result, after the transfer period ends, the switch SW4 is switched from a non-conductive state to a conductive state, and the switch SW2 is switched from a conductive state to a non-conductive state, so that the light emitting / detecting element SA can immediately emit light without newly writing data. This eliminates the need for a data writing period between the end of the transfer period and the display of an image, thereby shortening the period in which an image is not displayed (non-display period), and preventing a loss of display quality.

[0072] Moreover, Fig. 4C shows an example in which the switch SW2 in the configuration of Fig. 4A is eliminated. By configuring the switch SW4 to also perform the function of the switch SW2, the pixel circuit can be simplified.

[0073] [Configuration example 2] [Display Device Configuration Example 2-1] A more specific example of the structure of the display device of one embodiment of the present invention will be described below.

[0074] 5 is a block diagram illustrating the configuration of the display device 10. The display device 10 includes a display unit 11, a drive circuit unit 12, a drive circuit unit 13, a drive circuit unit 14, a circuit unit 15, and the like.

[0075] The display unit 11 has a plurality of pixels 30 arranged in a matrix. Each pixel 30 has sub-pixels 20R, 20G, and 20B. The sub-pixel 20R has a light emitting / receiving element, and the sub-pixels 20G and 20B each have a light emitting element.

[0076] The subpixel 20R is electrically connected to the wiring SL1, the wiring GL, the wiring RS, the wiring SE, the wiring WX, etc. The subpixel 20G is electrically connected to the wiring SL2, the wiring GL, etc. The subpixel 20B is electrically connected to the wiring SL3, the wiring GL, etc.

[0077] The wiring SL1, the wiring SL2, and the wiring SL3 are each electrically connected to a driving circuit unit 12. The wiring GL is electrically connected to a driving circuit unit 13. The driving circuit unit 12 functions as a source line driving circuit (also referred to as a source driver) and supplies data signals (data potentials) to each subpixel via the wirings SL1, SL2, and SL3. The driving circuit unit 13 functions as a gate line driving circuit (also referred to as a gate driver) and supplies a selection signal to the wiring GL.

[0078] The wiring RS and the wiring SE are each electrically connected to the drive circuit unit 14. The wiring WX is electrically connected to the circuit unit 15. The drive circuit unit 14 has a function of generating signals to be supplied to the subpixel 20R and outputting them to the wiring SE, wiring RS, etc. The drive circuit unit 14 also has a function of generating and outputting signals to be supplied to the wiring REN and wiring TX described below. Note that the drive circuit unit 13 or the drive circuit unit 12 may have a function of generating signals to be supplied to one or both of the wiring REN and wiring TX. The circuit unit 15 has a function of receiving signals output from the subpixel 20R via the wiring WX and outputting them to the outside as imaging data. The circuit unit 15 functions as a readout circuit.

[0079] [Pixel configuration example 2-1] 6 shows an example of a circuit diagram of pixel 30. Pixel 30 has subpixels 20R, 20G, and 20B. Subpixel 20R has a circuit 21R, a circuit 22, a light-emitting element SR, and a transistor M10. Subpixel 20G has a circuit 21G and a light-emitting element ELG. Subpixel 20B has a circuit 21B and a light-emitting element ELB.

[0080] The circuit 21R includes a transistor M1, a transistor M2, a capacitor C1, etc. The circuit 22 includes a transistor M11, a transistor M12, a transistor M13, a transistor M14, a capacitor C2, etc.

[0081] The circuit 21R functions as a circuit for controlling the light emission of the light emitting element SR when the light emitting element SR is used as a light emitting element. The circuit 21R has a function of controlling the current flowing through the light emitting element SR in accordance with the data potential applied from the wiring SL1.

[0082] Furthermore, when the light emitting / receiving element SR is used as a light receiving element, the circuit 22 functions as a sensor circuit for controlling the operation of the light emitting / receiving element SR. The circuit 22 has functions such as applying a reverse bias voltage to the light emitting / receiving element SR, controlling the exposure period of the light emitting / receiving element SR, holding a potential based on the charge transferred from the light emitting / receiving element SR, and outputting a signal based on the potential to the wiring WX.

[0083] The subpixel 20R shown in Fig. 6 corresponds to the configuration illustrated in Fig. 4B. The transistor M2 corresponds to the transistor Tr1 in Fig. 4B, and the transistor M13 corresponds to the transistor Tr2. Similarly, the transistor M1 corresponds to the switch SW1, the transistor M11 corresponds to the switch SW2, the transistor M12 corresponds to the switch SW3, and the transistor M10 corresponds to the switch SW4.

[0084] The transistor M1 has a gate electrically connected to a wiring GL, one of a source and a drain electrically connected to a wiring SL1, and the other electrically connected to the gate of the transistor M2 and one electrode of the capacitor C1. The transistor M2 has one of a source and a drain electrically connected to a wiring AL, and the other electrically connected to one of a source and a drain of the transistor M10 and the other electrode of the capacitor C1. The transistor M10 has a gate electrically connected to a wiring REN, and the other of a source and a drain electrically connected to one electrode of the light emitting / receiving element SR. The other electrode of the light emitting / receiving element SR is electrically connected to a wiring CL.

[0085] A data potential is applied to the wiring SL1. An anode potential is applied to the wiring AL. A cathode potential is applied to the wiring CL. In the configuration shown in FIG. 6, the anode potential is higher than the cathode potential. A signal that controls the conduction / non-conduction of the transistor M10 is applied to the wiring REN.

[0086] The transistor M11 has a gate electrically connected to a wiring TX, one of a source and a drain electrically connected to one electrode of the light emitting / receiving element SR and the other of the source and drain of the transistor M10, and the other electrically connected to the gate of the transistor M13, one of a source and a drain of the transistor M12, and one electrode of the capacitor C2. The transistor M12 has a gate electrically connected to a wiring RS, and the other of a source and a drain electrically connected to a wiring VL1. The other electrode of the capacitor C2 is electrically connected to a wiring VCP. The transistor M13 has one of a source and a drain electrically connected to a wiring VPI, and the other electrically connected to one of a source and a drain of the transistor M14. The transistor M14 has a gate electrically connected to a wiring SE, and the other of a source and a drain electrically connected to a wiring WX.

[0087] A signal that controls the conduction / non-conduction of the transistor M11 is applied to the wiring TX. RS is applied for different periods. A constant potential is applied to the wiring VCP. A constant potential is applied to the wiring VPI. In the configuration shown in FIG. 6, the potential V applied to the wiring VL1 is RS is preferably a potential lower than the cathode potential applied to the wiring CL.

[0088] The transistor M14 functions as a selection transistor for reading. The transistor M14 is controlled to be conductive or non-conductive by a signal applied to the wiring SE. By turning the transistor M14 on, the transistor M13 and the wiring WX are electrically connected, and a current (or voltage) corresponding to the gate potential of the transistor M13 can be output to the wiring WX.

[0089] Here, it is preferable to use transistors with extremely low leakage current in a non-conducting state as the transistors M1, M10, M11, M12, and M14, which function as switches. In particular, transistors using an oxide semiconductor for a semiconductor layer in which a channel is formed can be suitably used. It is also preferable to use transistors using an oxide semiconductor for the transistors M2 and M13, because all transistors can be formed through a common manufacturing process. Silicon (including amorphous silicon, polycrystalline silicon, and single-crystal silicon) may be used for the semiconductor layer in which a channel is formed in the transistors M2 and M13. However, this is not a limitation, and transistors using silicon may be used for some or all of the transistors. Furthermore, transistors using inorganic semiconductors, compound semiconductors, organic semiconductors, or the like other than silicon may be used for some or all of the transistors.

[0090] The subpixel 20G has a circuit 21G and a light-emitting element ELG. The subpixel 20B has a circuit 21B and a light-emitting element ELB. The circuits 21G and 21B have the same configuration.

[0091] The circuit 21G and the circuit 21B include a transistor M1, a transistor M2, a transistor M3, and a capacitor C1. The circuit 21G and the circuit 21B are similar to the circuit 21R except for including the transistor M3. The transistor M3 has a gate electrically connected to a wiring GL, one of a source and a drain electrically connected to the other electrode of the capacitor C1, the other of the source and drain of the transistor M2, and the anode of the light-emitting element ELG or the light-emitting element ELB, and the other electrically connected to a wiring V0L.

[0092] A constant potential is applied to the wiring V0L. For example, the same potential as the potential V0 applied to the wiring VL1 may be applied to the wiring V0L. Alternatively, the wiring VL1 may be used instead of the wiring V0L.

[0093] Here, a configuration may be adopted in which each transistor has a back gate, as shown in Fig. 7A, in which a pair of gates are electrically connected.

[0094] Note that, in FIG. 7A, all transistors have a pair of gates electrically connected, but this is not limiting. The pixel 30 may have a transistor having one gate connected to another wiring. For example, connecting one of the pair of gates to a wiring to which a constant potential is applied can improve the stability of electrical characteristics. Alternatively, one of the pair of gates may be connected to a wiring to which a potential for controlling the threshold voltage of the transistor is applied. Alternatively, as shown in FIG. 7B, a transistor may be used in which one of the pair of gates is connected to one of the source and drain. In this case, it is preferable to connect one of the gates to the source. For example, the transistors shown in FIG. 7B can be suitably used as the transistors M2, M12, and M13 in the pixel 30.

[0095] In addition, although an example in which all the transistors have a back gate has been shown here, the present invention is not limited to this, and transistors with a back gate and transistors without a back gate may be mixed.

[0096] [Pixel configuration example 2-2] Fig. 8A shows an example in which the transistor M10 is omitted from the subpixel 20R illustrated in Fig. 6. The configuration shown in Fig. 8A corresponds to the configuration illustrated in Fig. 1.

[0097] 8B shows an example in which a transistor having a back gate is applied to each transistor in FIG. 8A. In this example, a transistor having a pair of gates connected to each other is applied to all transistors. As described above, the method of connecting the back gates is not limited to this. As described above, a mixture of transistors without a back gate and transistors with a back gate may be used.

[0098] [Pixel configuration example 2-3] FIG. 9A shows an example in which the wiring WX is omitted from the subpixel 20R illustrated in FIG.

[0099] In FIG. 9A, the other of the source and the drain of the transistor M14 is electrically connected to the wiring SL1.

[0100] The wiring SL1 can also serve as the wiring WX. Specifically, by turning on the transistor M14, a current (or voltage) corresponding to the gate potential of the transistor M13 can be output to the wiring SL1. In this case, the wiring SL1 can be configured to be connected to both the driver circuit unit 12 and the circuit unit 15.

[0101] FIG. 9B shows an example in which the transistor M10 in FIG. 9A is omitted.

[0102] [Display Device Configuration Example 2-2] While the example in which one pixel has three sub-pixels has been described above, the following will describe an example in which one pixel has two sub-pixels.

[0103] Fig. 10A shows an example of an arrangement method for 3 x 3 pixels, showing pixels from the i-th row and j-th column (i and j are each independently an integer of 1 or greater) to the i+2-th row and j+2-th column.

[0104] 10A, pixels 30G and 30B are arranged alternately in the row and column directions. Pixel 30G includes subpixels 20R and 20G. Pixel 30B includes subpixels 20R and 20B.

[0105] For example, pixel 30G located in the i-th row and j-th column is connected to wiring GL[i], wiring RS[i], and wiring SE[i] extending in the row direction, and wiring SL1[j], wiring SL2[j], and wiring WX[j] extending in the column direction.

[0106] 10B shows an example of an arrangement method of the light-emitting / receiving elements SR, the light-emitting elements ELG, and the light-emitting elements ELB. The light-emitting / receiving elements SR are arranged at equal intervals in the row and column directions. The light-emitting elements ELG and the light-emitting elements ELB are arranged alternately in the row and column directions. The light-emitting / receiving elements SR, the light-emitting elements ELG, and the light-emitting elements ELB each have a square shape tilted at approximately 45 degrees with respect to the arrangement direction. This allows for a large distance between adjacent elements, and allows for good production yield when separately manufacturing light-emitting elements and light-emitting / receiving elements.

[0107] 11 shows an example of a circuit diagram for pixel 30G in the i-th row and j-th column and pixel 30B in the (i+1)-th row and j-th column. The configurations of subpixel 20R, subpixel 20G, and subpixel 20B can be seen from FIG. 6 and the like.

[0108] [Driving method example 1] An example of a method for driving a display device will be described below, taking as an example the configuration in which one pixel has two sub-pixels, as illustrated in Figs.

[0109] In the following description, the display device is assumed to have a display unit having a plurality of pixels arranged in a matrix of M rows and N columns (M and N are each independently an integer of 2 or more).

[0110] 12 and 13 are schematic diagrams showing the operation of a display device. The operation of a display device can be broadly divided into a period (display period) during which an image is displayed using light-emitting and light-emitting elements, and a period (imaging period) during which an image is captured using light-emitting and light-receiving elements (also called sensors). The display period is a period during which image data is written to pixels and a display based on the image data is performed. The imaging period is a period during which an image is captured by the light-emitting and light-receiving elements and the captured image data is read out.

[0111] First, the operation during the display period will be described with reference to FIG.

[0112] During the display period, data is repeatedly written to the pixels. During this period, the sensor does not operate (referred to as blank). Note that imaging can also be performed during the display period.

[0113] One write operation writes one frame of image data. As shown in Figure 12, one write operation (denoted as "write") writes data to pixels sequentially from the first column to the Mth column.

[0114] 12 shows a timing chart for writing data to the i-th row and the i+1-th row. The diagram shows the transition of potentials in the wirings GL[i], GL[i+1], RS[i], RS[i+1], SE, REN, VL1, SL1[j], and SL2[j]. Regarding the wirings SE, the wirings from the first row to the M-th column are collectively referred to as wirings SE[1:M]. Regarding the connection relationship between each wiring and each pixel, see FIGS. 10 and 11.

[0115] In the writing period of the i-th row, the wiring GL[i] and the wiring RS[i] are set to a high-level potential, and the other wirings GL and RS are set to a low-level potential. R [i,j] is the image data D G [i, j] are respectively applied. During the write period, a high-level potential is applied to the wiring REN, and a potential V0 is applied to the wiring VL1.

[0116] Similarly to the above, writing to the (i+1)th row and thereafter can be performed row by row by setting the corresponding wirings GL and RS to a high potential and applying image data to the wirings SL1 and SL2.

[0117] By performing this write operation from row 1 to row M, data writing for one frame is completed. During the display period, the above operation is repeatedly performed to display a moving image.

[0118] Next, the operation during the imaging period will be described with reference to Fig. 13. Here, the imaging operation using the global shutter method will be described. Note that the driving method is not limited to the global shutter method, and a rolling shutter method can also be applied.

[0119] The imaging period is divided into a period in which imaging is performed simultaneously in each pixel (referred to as imaging; hereinafter, to distinguish it from the imaging period, it is also referred to as imaging operation period) and a period in which imaging data is read out sequentially (referred to as readout). The imaging operation period is divided into an initialization period, an exposure period, and a transfer period. Furthermore, during the readout period, imaging data is read out row by row from the 1st row to the Mth row.

[0120] 13 shows a timing chart for the imaging operation period and the readout period. Here, the transition of potentials is shown for the wiring TX, wiring SE[i], wiring RS[i], wiring SE[i+1], wiring RS[i+1], wiring VL1, wiring REN, wiring SL[1:N], wiring GL[1:M], and wiring WX[1:N]. Here, the wirings GL are collectively referred to as wiring GL[1:M], and the wirings WX are collectively referred to as wiring WX[1:N]. Furthermore, the wirings SL1 and SL2, etc., are collectively referred to as wiring SL[1:N].

[0121] During the initialization period, the line REN is set to a low potential, which causes the transistor M10 to be non-conductive in all pixels, thereby electrically isolating the light emitting / receiving element SR from the transistor M2.

[0122] The wiring TX and all wiring RS are set to a high level potential, and the wiring VL1 is set to a potential V RS By applying a potential V RS This causes the reset operation of all pixels to be performed.

[0123] Subsequently, during the exposure period, the wiring TX and the wiring RS are set to a low level potential, which causes charges corresponding to the irradiated light to be accumulated in the light emitting / receiving element SR.

[0124] Next, during the transfer period, the line TX is set to a high-level potential, which allows the charge accumulated in the light emitting element SR to be transferred to the node connected to the gate of the transistor M13. After that, the line TX is set to a low-level potential, thereby maintaining the potential of the node.

[0125] Next, the image data is read out for each row. During the readout period, a high-level potential is applied to the wirings SE[1] to SE[N] in order, thereby reading out data for all pixels. For example, in the readout of the i-th row, the wiring SE[i] is set to a high-level potential, and the data D of the i-th row is applied to the wirings WX[1:N]. W Specifically, data D in the i-th row and j-th column is output to one wiring WX[j]. W [i,j] is output.

[0126] In FIG. 13, in the data read operation of the i-th row, a high-level potential is applied to the wiring SE[i], and data D W After the signal RS[i] is output, a high-level potential is applied to the wiring RS[i]. This causes the gate of the transistor M13 to be supplied with a potential V RS The data in this state is output to the wiring WX[1:N]. The circuit unit 15 to which the wiring WX is connected can perform correlated double sampling (CDS) using these two output data, thereby reducing the influence of variations in electrical characteristics for each pixel.

[0127] During the imaging period, a low-level potential is always applied to the line REN. This electrically insulates the light emitting / receiving element SR from the transistor M2, particularly during the exposure and transfer periods. This reduces noise and enables highly accurate imaging.

[0128] Furthermore, during the imaging period, it is preferable that each pixel retains (referred to as retained) the image data written immediately before. As a result, when the imaging period ends and the potential of the line REN changes from low to high, an image corresponding to the retained image data can be displayed immediately. Furthermore, by retaining the image data written to the subpixel 20G or the subpixel 20B during the imaging period, crosstalk noise to the anode of the light emitting / receiving element SR in the subpixel 20R can be reduced.

[0129] This concludes the description of driving method example 1.

[0130] [Configuration example 3] Below, an example of the configuration of a display device having a different configuration from the above will be described.

[0131] [Pixel configuration example 3-1] The pixel circuit shown in FIG. 14A has the same configuration as that shown in FIG. 6 and the like, except that the transistor M11 and the capacitor C2 are omitted.

[0132] 14A, the other of the source and drain of the transistor M2 is electrically connected to one of the source and drain of the transistor M10, one of the source and drain of the transistor M12, and the gate of the transistor M13. The other of the source and drain of the transistor M10 is electrically connected to the anode of the light emitting / receiving element SR.

[0133] With this configuration, the transistor M10 can also function as the transistor M11 in the configuration shown in Figure 6 etc. Therefore, the transistor M11 and the wiring TX can be omitted, and the pixel configuration can be simplified.

[0134] 14A, the capacitor C1 can also function as the capacitor C2 in the configurations shown in FIG. 6 and other figures. That is, the capacitor C1 can also function as a storage capacitor that holds the potential of the node to which the gate of the transistor M13 is connected. This makes it possible to omit the capacitor C2 and the wiring VCP compared to the configurations shown in FIG. 6 and other figures, thereby further simplifying the pixel configuration.

[0135] Here, the capacitor C1 is not connected to a wiring that applies a constant potential. Therefore, when charging or discharging one of the pair of electrodes of the capacitor C1, it is preferable to apply a constant potential to the other. Specifically, a constant potential (for example, a potential V off ), or a constant potential (for example, potential V0 or potential V RS ) is preferably given.

[0136] 14B shows an example in which a transistor having a back gate is applied to each transistor in FIG. 14A. In this example, a transistor having a pair of gates connected to each other is applied to all transistors. As described above, the method of connecting the back gates is not limited to this. Also, as described above, a mixture of transistors without a back gate and transistors with a back gate may be used.

[0137] [Pixel configuration example 3-2] 15 shows an example in which the wiring WX is omitted from the configuration shown in FIG. 14A. The other of the source and drain of the transistor M14 is electrically connected to the wiring SL1. The wiring SL1 can also function as the wiring WX. This can further simplify the pixel configuration.

[0138] [Display Device Configuration Example 3] The pixel circuits illustrated in FIGS. 14A, 14B, and 15 can be applied to the subpixel 20R of the display devices illustrated in FIGS. 5, 10A, and the like.

[0139] Fig. 16 shows an example in which the pixel circuit illustrated in Fig. 14A is applied to the display device of Fig. 10. Here, as in Fig. 11, an example of a circuit diagram is shown for pixel 30G in the i-th row and j-th column and pixel 30B in the i+1-th row and j-th column.

[0140] [Driving method example 2] Another example of a method for driving a display device will be described below, taking the configuration shown in FIG.

[0141] Note that the same parts as those in the driving method example 1 above will be used, and the explanation may be omitted.

[0142] For the operation during the display period, the same method as the driving method example 1 and the method exemplified in FIG. 12 can be applied.

[0143] The operation during the imaging period will be described below with reference to Fig. 17. Here too, the case where imaging operation is performed using the global shutter method will be described.

[0144] Figure 17 shows the potential changes for wiring REN, wiring SE[i], wiring RS[i], wiring SE[i+1], wiring RS[i+1], wiring VL1, wiring SL1[1:N], wiring GL[1:M], and wiring WX.

[0145] In the initialization period, the wiring REN and all the wirings RS are set to a high-level potential. As a result, the potential V RS is given.

[0146] In addition, all the wirings GL[1:M] are set to a high level potential, and all the wirings SL1[1:N] are set to a potential V off As a result, the potential V off is applied, allowing transistor M2 to be non-conductive.

[0147] Subsequently, during the exposure period, the wirings REN, RS, GL, etc. are set to a low level potential, thereby accumulating charges according to the light irradiated to the light emitting / receiving elements SR.

[0148] Subsequently, in the transfer period, the line REN is set to a high level potential, which allows the charge stored in the light emitting / receiving element SR to be transferred to the node to which the gate of the transistor M13 is connected.

[0149] In this case, if the node to which the gate of the transistor M2 is connected is in a floating state, when the transistor M10 is turned on after exposure, the potential of the node to which the gate of the transistor M2 is connected may increase due to capacitive coupling by the capacitor C1. Therefore, as shown in FIG. 17, during the transfer period, a high-level potential is applied to the wiring GL[1:M] and a potential V off Preferably, by applying a voltage Vout of 1 V, transistor M2 is kept in an off state.

[0150] Next, the image data is read out row by row. During the readout period, data can be read out for all pixels by applying a high-level potential to the line SE, row by row, in the same manner as described above. Alternatively, during the readout period for one row, a high-level potential may be applied to the line RS, outputting two types of data to the line WX, and CDS may be performed by the circuit unit 15.

[0151] During the exposure period and the readout period, a low level potential is applied to all the wirings GL, and the transistor M1 is in a non-conducting state. As a result, the gate of the transistor M2 is supplied with a potential Voff Since the potential is maintained at the applied state, it is possible to suppress current flow through the transistor M2. As a result, it is possible to perform imaging with reduced noise. Note that, since the transistor M1 is in a non-conducting state at this time, it does not matter what potential is applied to the wiring SL1 (referred to as "don't care").

[0152] This concludes the description of the second driving method example.

[0153] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0154] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0155] (Embodiment 2) In this embodiment, a display device according to one embodiment of the present invention will be described.

[0156] A display device according to one embodiment of the present invention includes a light-emitting element and a light-emitting and receiving element.

[0157] The light-receiving and light-emitting element can be fabricated by combining an organic EL element, which is a light-emitting element, with an organic photodiode, which is a light-receiving element. For example, the light-receiving and light-emitting element can be fabricated by adding an active layer of an organic photodiode to the layered structure of the organic EL element. Furthermore, the light-receiving and light-emitting element fabricated by combining an organic EL element and an organic photodiode can suppress an increase in the number of film formation steps by simultaneously forming layers that can have a common configuration with the organic EL element.

[0158] 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.

[0159] Note that the layers of the light-emitting / receiving element may have different functions when the light-emitting / receiving element functions as a light-receiving element and when it functions as a light-emitting element. In this specification, components are named based on their functions when the light-emitting / receiving element functions as a light-emitting element. For example, a hole injection layer functions as a hole injection layer when the light-emitting / receiving element functions as a light-emitting element, and functions as a hole transport layer when the light-emitting / receiving element functions as a light-receiving element. Similarly, an electron injection layer functions as an electron injection layer when the light-emitting / receiving element functions as a light-emitting element, and functions as an electron transport layer when the light-emitting / receiving element functions as a light-receiving element.

[0160] As described above, the display device of this embodiment has a light-emitting / receiving element and a light-emitting element in a display portion. Specifically, the light-emitting / receiving element and the light-emitting element are arranged in a matrix in the display portion. Therefore, the display portion has one or both of an imaging function and a sensing function in addition to a function of displaying an image.

[0161] The display unit can be used as an image sensor, a touch sensor, or the like. That is, by detecting light in the display unit, it is possible to capture an image, detect the approach or contact of an object (a finger, a pen, or the like), and the like. Furthermore, in the display device of this embodiment, the light-emitting element can be used as a light source for the sensor. Therefore, it is not necessary to provide a light-receiving unit and a light source separately from the display device, and the number of components in the electronic device can be reduced.

[0162] In the display device of this embodiment, when an object reflects the light emitted from the light-emitting element of the display unit, the light-receiving and light-emitting element can detect the reflected light, so that imaging, touch (contact or approach) detection, and the like are possible even in dark places.

[0163] The display device of this embodiment mode has a function of displaying an image using a light-emitting element and a light-emitting and light-emitting element. That is, the light-emitting element and the light-emitting and light-emitting element function as display elements.

[0164] 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), an inorganic compound (such as a quantum dot material), and a material that exhibits thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) material). Furthermore, an LED such as a micro LED (Light Emitting Diode) can also be used as the light-emitting element.

[0165] 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.

[0166] When the light emitting / receiving elements are used in an image sensor, the display device of this embodiment can capture an image using the light emitting / receiving elements. For example, the display device of this embodiment can be used as a scanner.

[0167] For example, data such as fingerprints and palm prints can be acquired using an image sensor. That is, a biometric authentication sensor can be built into the display device of the present embodiment. By building a biometric authentication sensor into the display device, the number of components in the electronic device can be reduced compared to when a biometric authentication sensor is provided separately from the display device, and the electronic device can be made smaller and lighter.

[0168] In addition, an image sensor can be used to acquire data such as the user's facial expression, eye movement, or changes in pupil diameter. By analyzing this data, it is possible to acquire information about the user's mind and body. By changing the display and / or audio output content based on this information, it is possible to ensure the user's safe use of devices, for example, for virtual reality (VR), augmented reality (AR), or mixed reality (MR).

[0169] Furthermore, when the light emitting and receiving elements are used as a touch sensor, the display device of this embodiment can detect the approach or contact of an object by using the light emitting and receiving elements.

[0170] The light emitting / receiving element functions as a photoelectric conversion element that detects light incident on the light emitting / receiving element and generates electric charges. The amount of electric charges generated is determined based on the amount of incident light.

[0171] The light emitting / receiving element can be fabricated by adding an active layer of a light receiving element to the above-described light emitting element configuration.

[0172] The light emitting / receiving element may be, for example, an active layer of a pn-type or pin-type photodiode.

[0173] 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.

[0174] 18A to 18D show cross-sectional views of display devices according to embodiments of the present invention.

[0175] A display device 350A shown in FIG. 18A includes, between a substrate 351 and a substrate 359, a layer 353 having a light emitting / receiving element and a layer 357 having a light emitting element.

[0176] A display device 350B shown in FIG. 18B includes, between a substrate 351 and a substrate 359, a layer 353 having a light emitting / receiving element, a layer 355 having a transistor, and a layer 357 having a light emitting element.

[0177] The display devices 350A and 350B have a structure in which green (G) light and blue (B) light are emitted from the layer 357 having the light-emitting elements, and red (R) light is emitted from the layer 353 having the light-emitting and light-emitting elements. Note that in the display device of one embodiment of the present invention, the color of light emitted from the layer 353 having the light-emitting and light-emitting elements is not limited to red.

[0178] The light emitting / receiving elements included in the layer 353 having the light emitting / receiving elements can detect light incident from outside the display device 350A or the display device 350B. The light emitting / receiving elements can detect, for example, one or both of green (G) light and blue (B) light.

[0179] A display device according to one embodiment of the present invention has a plurality of pixels arranged in a matrix. Each pixel has one or more subpixels. Each subpixel has one light-emitting / receiving element or one light-emitting element. For example, a pixel may have three subpixels (e.g., three colors of R, G, and B, or three colors of yellow (Y), cyan (C), and magenta (M)) or four subpixels (e.g., four colors of R, G, B, and white (W), or four colors of R, G, B, and Y). At least one subpixel of one color has a light-emitting / receiving element. The light-emitting / receiving element may be provided in all or some of the pixels. Furthermore, one pixel may have multiple light-emitting / receiving elements.

[0180] The layer 355 having transistors includes, for example, a transistor electrically connected to a light-emitting / receiving element and a transistor electrically connected to a light-emitting element. The layer 355 having transistors may further include wirings, electrodes, terminals, capacitors, resistors, and the like.

[0181] The display device of one embodiment of the present invention may have a function to detect an object such as a finger in contact with the display device (FIG. 18C). Alternatively, it may have a function to detect an object approaching (not in contact with) the display device (FIG. 18D). For example, as shown in FIGS. 18C and 18D, light emitted from a light-emitting element in a layer 357 having a light-emitting element is reflected by a finger 352 that has come into contact with or approached the display device 350B, and the reflected light is detected by a light-emitting element in a layer 353 having a light-emitting element. This makes it possible to detect that the finger 352 has come into contact with or approached the display device 350B.

[0182] [Pixels] 18E to 18G and 19A to 19D show examples of pixels. Note that the arrangement of the subpixels is not limited to the order shown in the drawings. For example, the positions of the subpixels 311B and 311G may be reversed.

[0183] 18E is a striped arrangement, and includes a subpixel 311SR that emits red light and has a light-receiving function, a subpixel 311G that emits green light, and a subpixel 311B that emits blue light. In a display device in which a pixel is composed of three subpixels of R, G, and B, by replacing the light-emitting element used in the R subpixel with a light-receiving / light-emitting element, a display device in which the pixel has a light-receiving function can be manufactured.

[0184] 18F is arranged in a matrix and includes subpixel 311SR that emits red light and has a light-receiving function, subpixel 311G that emits green light, subpixel 311B that emits blue light, and subpixel 311W that emits white light. Even in a display device in which a pixel is composed of four subpixels of R, G, B, and W, a display device in which the pixel has a light-receiving function can be manufactured by replacing the light-emitting element used in the R subpixel with a light-receiving / light-emitting element.

[0185] The pixels shown in Figure 18G are arranged in a Pentile array and have sub-pixels that emit two different colors of light. The upper left and lower right pixels shown in Figure 18G have sub-pixel 311SR that emits red light and has a light-receiving function, and sub-pixel 311G that emits green light. The lower left and upper right pixels shown in Figure 18G have sub-pixel 311G that emits green light and sub-pixel 311B that emits blue light. The shapes of the sub-pixels shown in Figure 18G indicate the top shapes of the light-emitting or light-receiving elements of the sub-pixels.

[0186] 19A includes a subpixel 311SR that emits red light and has a light-receiving function, a subpixel 311G that emits green light, and a subpixel 311B that emits blue light. The subpixel 311SR is arranged in a column different from the subpixels 311G and 311B. The subpixels 311G and 311B are arranged alternately in the same column, with one being arranged in an odd-numbered row and the other being arranged in an even-numbered row. Note that the subpixel arranged in a column different from the subpixels of other colors is not limited to red (R) and may be green (G) or blue (B).

[0187] FIG. 19B shows two pixels, each consisting of three subpixels surrounded by dotted lines. The pixel shown in FIG. 19B has a subpixel 311SR that emits red light and has a light-receiving function, a subpixel 311G that emits green light, and a subpixel 311B that emits blue light. In the pixel on the left shown in FIG. 19B, the subpixel 311G is arranged in the same row as the subpixel 311SR, and the subpixel 311B is arranged in the same column as the subpixel 311SR. In the pixel on the right shown in FIG. 19B, the subpixel 311G is arranged in the same row as the subpixel 311SR, and the subpixel 311B is arranged in the same column as the subpixel 311G. In the pixel layout shown in FIG. 19B, the subpixels 311SR, 311G, and 311B are arranged repeatedly in both odd-numbered and even-numbered rows, and in each column, subpixels of different colors are arranged in the odd-numbered and even-numbered rows.

[0188] Figure 19C is a modification of the pixel array shown in Figure 18G. The upper left pixel and lower right pixel shown in Figure 19C have a sub-pixel 311SR that emits red light and has a light-receiving function, and a sub-pixel 311G that emits green light. The lower left pixel and upper right pixel shown in Figure 19C have a sub-pixel 311SR that emits red light and has a light-receiving function, and a sub-pixel 311B that emits blue light.

[0189] In FIG. 18G, each pixel is provided with a sub-pixel 311G that emits green light. On the other hand, in FIG. 19C, each pixel is provided with a sub-pixel 311SR that emits red light and has a light-receiving function. Because each pixel is provided with a sub-pixel that has a light-receiving function, the configuration shown in FIG. 19C can capture images with higher resolution than the configuration shown in FIG. 18G. This can, for example, improve the accuracy of biometric authentication.

[0190] Furthermore, 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. Fig. 18G shows an example of a circular top surface shape of the light-emitting element of the subpixel 311G, and Fig. 19C shows an example of a square top surface shape. 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.

[0191] The aperture ratios of the subpixels of each color may be different from each other, or may be the same for some or all of the colors. For example, the aperture ratio of the subpixel provided in each pixel (subpixel 311G in FIG. 18G, subpixel 311SR in FIG. 19C) may be smaller than the aperture ratios of the subpixels of other colors.

[0192] Fig. 19D is a modified example of the pixel array shown in Fig. 19C. Specifically, the configuration in Fig. 19D is obtained by rotating the configuration in Fig. 19C by 45°. In Fig. 19C, it has been described that one pixel is made up of two sub-pixels, but as shown in Fig. 19D, it can also be understood that one pixel is made up of four sub-pixels.

[0193] In FIG. 19D, a single pixel is described as being composed of four subpixels surrounded by dotted lines. One pixel has two subpixels 311SR, one subpixel 311G, and one subpixel 311B. By having a single pixel thus include multiple subpixels with light receiving functions, it is possible to capture images with high resolution. This can improve the accuracy of biometric authentication. For example, the resolution of the image can be set to the root double of the resolution of the display.

[0194] A display device to which the configuration shown in Figure 19C or 19D 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.

[0195] For example, when touch detection is performed using a light-emitting / receiving element, it is preferable that the light emitted from the light source is difficult for the user to see. 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.

[0196] As described above, pixels with various arrangements can be applied to the display device of one embodiment of the present invention.

[0197] In the display device of this embodiment, there is no need to change the pixel arrangement in order to incorporate a light-receiving function into the pixel, and therefore, one or both of an imaging function and a sensing function can be added to the display portion without reducing the aperture ratio and the resolution.

[0198] [Light emitting / receiving element] 20A to 20E show examples of the layered structure of the light emitting and receiving element.

[0199] The light emitting / receiving element has at least an active layer and a light emitting layer between a pair of electrodes.

[0200] The light-emitting / receiving element may further include a layer containing a substance with high hole-injecting property, a substance with high hole-transporting property, a substance with high hole-blocking property, a substance with high electron-transporting property, a substance with high electron-injecting property, a substance with high electron-blocking property, or a bipolar substance (a substance with high electron-transporting property and high hole-transporting property), as a layer other than the active layer and the light-emitting layer.

[0201] The light emitting and receiving elements shown in Figures 20A to 20C each have a first electrode 180, a hole injection layer 181, a hole transport layer 182, an active layer 183, a light emitting layer 193, an electron transport layer 184, an electron injection layer 185, and a second electrode 189.

[0202] 20A to 20C can be considered to have a configuration in which an active layer 183 is added to a light-emitting element. Therefore, by simply adding a step of forming the active layer 183 to the manufacturing process of the light-emitting element, the light-emitting / receiving element can be formed in parallel with the formation 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 number of manufacturing steps.

[0203] The stacking order of the light-emitting layer 193 and the active layer 183 is not limited. Fig. 20A shows an example in which the active layer 183 is provided on the hole-transport layer 182, and the light-emitting layer 193 is provided on the active layer 183. Fig. 20B shows an example in which the light-emitting layer 193 is provided on the hole-transport layer 182, and the active layer 183 is provided on the light-emitting layer 193. The active layer 183 and the light-emitting layer 193 may be in contact with each other, as shown in Figs. 20A and 20B.

[0204] As shown in Fig. 20C, it is preferable that a buffer layer is sandwiched between the active layer 183 and the light-emitting layer 193. The buffer layer can be at least one layer selected from the group consisting of 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. Fig. 20C shows an example in which a hole transport layer 182 is used as the buffer layer.

[0205] By providing a buffer layer between the active layer 183 and the light-emitting layer 193, it is possible to suppress the transfer of excitation energy from the light-emitting layer 193 to the active layer 183. In addition, the buffer layer can also be used to adjust the optical path length (cavity length) of the microresonance (microcavity) structure. Therefore, a light-emitting / receiving element having a buffer layer between the active layer 183 and the light-emitting layer 193 can obtain high light-emitting efficiency.

[0206] 20A and 20C in that it does not have the hole transport layer 182. The light emitting / receiving element may not have at least one layer selected from the hole injection layer 181, the hole transport layer 182, the electron transport layer 184, and the electron injection layer 185. The light emitting / receiving element may also have other functional layers such as a hole blocking layer and an electron blocking layer.

[0207] The light emitting / receiving device shown in FIG. 20E differs from the light emitting / receiving device shown in FIGS. 20A to 20C in that it does not have the active layer 183 and the light emitting layer 193, but has a layer 186 that serves as both the light emitting layer and the active layer.

[0208] The layer 186 serving as both the light-emitting layer and the active layer may be, for example, a layer containing three materials: an n-type semiconductor that can be used for the active layer 183, a p-type semiconductor that can be used for the active layer 183, and a light-emitting substance that can be used for the light-emitting layer 193.

[0209] 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.

[0210] 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.

[0211] When the light emitting / receiving element is operated as a light emitting element, the hole injection layer is a layer that injects holes from the anode into the hole transport layer. The hole injection layer is a layer containing a material with high hole injection properties. As the material with high hole injection properties, a composite material containing a hole transport material and an acceptor material (electron accepting material), an aromatic amine compound (a compound having an aromatic amine skeleton), or the like can be used.

[0212] When the light emitting / receiving element is operated as 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. When the light emitting / receiving element is operated as 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 compound, is preferred.

[0213] When the light emitting / receiving element is operated as 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. When the light emitting / receiving element is operated as 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 containing 1×10 -6 cm 2 A 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.

[0214] When the light emitting / receiving element is operated as a light emitting element, the electron injection layer is a layer that injects electrons from the cathode to the electron transport layer. The electron injection layer is a layer containing a material with high electron injection properties. As the material with high electron injection properties, alkali metals, alkaline earth metals, or compounds thereof can be used. As the material with high electron injection properties, a composite material containing an electron transport material and a donor material (electron donor material) can also be used.

[0215] The light-emitting layer 193 is a layer containing a light-emitting substance. The light-emitting layer 193 can contain 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.

[0216] Examples of light-emitting materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0217] 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.

[0218] 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.

[0219] The light-emitting layer 193 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.

[0220] The light-emitting layer 193 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, allowing efficient emission. This structure simultaneously enables high efficiency, low-voltage operation, and a long lifetime of the light-emitting element.

[0221] 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).

[0222] 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.

[0223] The active layer 183 includes a semiconductor. Examples of the semiconductor include an inorganic semiconductor such as silicon and an organic semiconductor including an organic compound. In this embodiment, an example in which an organic semiconductor is used as the semiconductor included in the active layer is shown. By using an organic semiconductor, the light-emitting layer 193 and the active layer 183 can be formed by the same method (for example, vacuum deposition), which is preferable because a common manufacturing device can be used.

[0224] The active layer 183 is made of 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.

[0225] 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.

[0226] Examples of the p-type semiconductor material of the active layer 183 include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin phthalocyanine (SnPc), and quinacridone.

[0227] Examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, aromatic amine compounds, 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.

[0228] 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.

[0229] 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.

[0230] For example, the active layer 183 is preferably formed by co-evaporating an n-type semiconductor and a p-type semiconductor.

[0231] The layer 186 that functions as both a light-emitting layer and an active layer is preferably formed using the above-mentioned light-emitting material, n-type semiconductor, and p-type semiconductor.

[0232] The hole injection layer 181, the hole transport layer 182, the active layer 183, the light-emitting layer 193, the electron transport layer 184, the electron injection layer 185, and the layer serving as both the light-emitting layer and the active layer 186 can be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound. Each layer can be formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, or a coating method.

[0233] Below, a detailed structure of a light-emitting and light-emitting element included in a display device of one embodiment of the present invention will be described with reference to FIGS.

[0234] 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.

[0235] 21 to 23, a top-emission display device will be described as an example.

[0236] [Configuration example 1] The display device shown in Figures 21A and 21B has, on a substrate 151, a light-emitting element 347B that emits blue (B) light, a light-emitting element 347G that emits green (G) light, and a light-receiving element 347SR that emits red (R) light and has a light-receiving function, via a layer 355 having a transistor.

[0237] 21A shows a case where the light emitting / receiving element 347SR functions as a light emitting element. In FIG. 21A, an example is shown in which the light emitting element 347B emits blue light, the light emitting element 347G emits green light, and the light emitting / receiving element 347SR emits red light.

[0238] Fig. 21B shows a case where the light receiving / emitting element 347SR functions as a light receiving element. Fig. 21B shows an example in which the light receiving / emitting element 347SR detects blue light emitted by the light emitting element 347B and green light emitted by the light emitting element 347G.

[0239] The light emitting element 347B, the light emitting element 347G, and the light emitting / receiving element 347SR each have a pixel electrode 191 and a common electrode 115. In this embodiment, a case will be described as an example in which the pixel electrode 191 functions as an anode and the common electrode 115 functions as a cathode.

[0240] In this embodiment, similarly to the light-emitting element, the light receiving / emitting element 347SR will be described as having the pixel electrode 191 function as an anode and the common electrode 115 function as a cathode. In other words, the light receiving / emitting element 347SR can be driven by applying a reverse bias between the pixel electrode 191 and the common electrode 115 to detect light incident on the light receiving / emitting element 347SR, generate electric charges, and extract the charges as a current.

[0241] The common electrode 115 is used in common by the light emitting element 347B, the light emitting element 347G, and the light emitting / receiving element 347SR.

[0242] The materials and thicknesses of the pairs of electrodes of the light-emitting element 347B, the light-emitting element 347G, and the light-emitting / receiving element 347SR can be made the same, which leads to a reduction in manufacturing costs and a simplification of the manufacturing process of the display device.

[0243] The configuration of the display device shown in FIGS. 21A and 21B will be specifically described.

[0244] The light-emitting element 347B has a buffer layer 192B, a light-emitting layer 193B, and a buffer layer 194B in this order over a pixel electrode 191. The light-emitting layer 193B contains a light-emitting material that emits blue light. The light-emitting element 347B has a function of emitting blue light.

[0245] The light-emitting element 347G has a buffer layer 192G, a light-emitting layer 193G, and a buffer layer 194G in this order on a pixel electrode 191. The light-emitting layer 193G contains a light-emitting material that emits green light. The light-emitting element 347G has a function of emitting green light.

[0246] The light emitting / receiving element 347SR has a buffer layer 192R, an active layer 183, a light emitting layer 193R, and a buffer layer 194R, in this order, on the pixel electrode 191. The light emitting layer 193R contains a light emitting material that emits red light. The active layer 183 contains an organic compound that absorbs light of a shorter wavelength than red light (for example, one or both of green light and blue light). Note that the active layer 183 may use an organic compound that absorbs not only visible light but also ultraviolet light. The light emitting / receiving element 347SR has a function of emitting red light. The light emitting / receiving element 347SR has a function of detecting the light emitted by at least one of the light emitting elements 347G and 347B, and preferably has a function of detecting the light emitted by both of them.

[0247] The active layer 183 preferably contains an organic compound that does not easily absorb red light and absorbs light with a shorter wavelength than red light, thereby enabling the light emitting / receiving element 347SR to efficiently emit red light and accurately detect light with a shorter wavelength than red light.

[0248] The pixel electrode 191, the buffer layer 192R, the buffer layer 192G, the buffer layer 192B, the active layer 183, the light-emitting layer 193R, the light-emitting layer 193G, the light-emitting layer 193B, the buffer layer 194R, the buffer layer 194G, the buffer layer 194B, and the common electrode 115 may each have a single-layer structure or a multilayer structure.

[0249] In the display devices shown in FIGS. 21A and 21B, the buffer layer, active layer, and light-emitting layer are layers that are fabricated separately for each device.

[0250] The buffer layers 192R, 192G, and 192B may each have one or both of a hole injection layer and a hole transport layer. Furthermore, the buffer layers 192R, 192G, and 192B may also have an electron blocking layer. The buffer layers 194B, 194G, and 194R may each have one or both of an electron injection layer and an electron transport layer. Furthermore, the buffer layers 194R, 194G, and 194B may also have a hole blocking layer. For the materials and the like of each layer constituting the light-emitting element, the above-mentioned description of each layer constituting the light-emitting element can be referred to.

[0251] [Configuration example 2] 22A and 22B, the light-emitting element 347B, the light-emitting element 347G, and the light-emitting / receiving element 347SR may have a common layer between a pair of electrodes, which allows the light-emitting / receiving elements to be incorporated into the display device without significantly increasing the number of manufacturing steps.

[0252] The light emitting element 347B, the light emitting element 347G, and the light emitting / receiving element 347SR shown in FIG. 22A have a common layer 112 and a common layer 114 in addition to the configuration shown in FIGS. 21A and 21B.

[0253] The light-emitting element 347B, light-emitting element 347G, and light-receiving element 347SR shown in Figure 22B differ from the configurations shown in Figures 21A and 21B in that they do not have buffer layers 192R, 192G, 192B and buffer layers 194R, 194G, 194B, but have common layers 112 and 114.

[0254] The common layer 112 may have one or both of a hole injection layer and a hole transport layer, and the common layer 114 may have one or both of an electron injection layer and an electron transport layer.

[0255] Each of the common layer 112 and the common layer 114 may have a single layer structure or a laminated structure.

[0256] [Configuration example 3] The display device shown in FIG. 23A is an example in which the laminated structure shown in FIG. 20C is applied to a light emitting / receiving element 347SR.

[0257] The light emitting / receiving element 347SR has, on a pixel electrode 191, a hole injection layer 181, an active layer 183, a hole transport layer 182R, a light emitting layer 193R, an electron transport layer 184, an electron injection layer 185, and a common electrode 115 in this order.

[0258] The hole injection layer 181, the electron transport layer 184, the electron injection layer 185, and the common electrode 115 are layers common to the light emitting element 347G and the light emitting element 347B.

[0259] The light emitting element 347G has a hole injection layer 181, a hole transport layer 182G, a light emitting layer 193G, an electron transport layer 184, an electron injection layer 185, and a common electrode 115 on a pixel electrode 191 in this order.

[0260] The light emitting element 347B has a hole injection layer 181, a hole transport layer 182B, a light emitting layer 193B, an electron transport layer 184, an electron injection layer 185, and a common electrode 115 on a pixel electrode 191 in this order.

[0261] The light-emitting element included in the display device of this embodiment preferably has a microcavity structure. Therefore, one of a pair of electrodes included in the light-emitting element is preferably an electrode that is transparent and reflective to visible light (semi-transmissive / semi-reflective electrode), and the other is preferably 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 the two electrodes, thereby intensifying the light emitted from the light-emitting element.

[0262] 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). In this specification, the reflective electrode, which functions as a part of the semi-transmitting / semi-reflective electrode, is sometimes referred to as a pixel electrode or a common electrode, and the transparent electrode is sometimes referred to as an optical adjustment layer, but it can also be said that the transparent electrode (optical adjustment layer) functions as a pixel electrode or a common electrode.

[0263] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode for the light emitting element that has a transmittance of 40% or more for both visible light (light with a wavelength of 400 nm or more and less than 750 nm) and near-infrared light (light with a wavelength of 750 nm or more and 1300 nm or less). The reflectance of the semi-transparent / semi-reflective electrode for both visible light and near-infrared light is 10% or more and 95% or less, preferably 30% or more and 80% or less. The reflectance of the reflective electrode for both visible light and near-infrared light is 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes is 1×10 -2 Ωcm or less is preferable.

[0264] The hole transport layers 182B, 182G, and 182R may each function as an optical adjustment layer. Specifically, in the light-emitting element 347B, it is preferable to adjust the film thickness of the hole transport layer 182B so that the optical distance between the pair of electrodes is an optical distance that intensifies blue light. Similarly, in the light-emitting element 347G, it is preferable to adjust the film thickness of the hole transport layer 182G so that the optical distance between the pair of electrodes is an optical distance that intensifies green light. And, in the light-receiving / light-emitting element 347SR, it is preferable to adjust the film thickness of the hole transport layer 182R so that the optical distance between the pair of electrodes is an optical distance that intensifies red light. The layer used as the optical adjustment layer is not limited to the hole transport layer. Note that, when the semi-transmitting / semi-reflective electrode has a stacked structure of a reflective electrode and a transparent electrode, the optical distance between the pair of electrodes refers to the optical distance between the pair of reflective electrodes.

[0265] [Configuration example 4] The display device shown in FIG. 23B is an example in which the laminated structure shown in FIG. 20D is applied to a light emitting / receiving element 347SR.

[0266] The light emitting / receiving element 347SR has, on a pixel electrode 191, a hole injection layer 181, an active layer 183, a light emitting layer 193R, an electron transport layer 184, an electron injection layer 185, and a common electrode 115 in this order.

[0267] The hole injection layer 181, the electron transport layer 184, the electron injection layer 185, and the common electrode 115 are layers common to the light emitting element 347G and the light emitting element 347B.

[0268] The light emitting element 347G has a hole injection layer 181, a hole transport layer 182G, a light emitting layer 193G, an electron transport layer 184, an electron injection layer 185, and a common electrode 115 on a pixel electrode 191 in this order.

[0269] The light emitting element 347B has a hole injection layer 181, a hole transport layer 182B, a light emitting layer 193B, an electron transport layer 184, an electron injection layer 185, and a common electrode 115 on a pixel electrode 191 in this order.

[0270] The hole transport layer is provided in the light-emitting element 347G and the light-emitting element 347B, but not in the light-receiving / light-emitting element 347SR. In this way, in addition to the active layer and the light-emitting layer, there may be a layer that is provided in only one of the light-emitting element and the light-receiving / light-emitting element.

[0271] A detailed configuration of a display device according to one embodiment of the present invention will be described below with reference to FIGS.

[0272] [Display device 310A] 24A and 24B show cross-sectional views of the display device 310A.

[0273] The display device 310A has a light emitting element 190B, a light emitting element 190G, and a light emitting / receiving element 190SR.

[0274] The light emitting element 190B has a pixel electrode 191, a buffer layer 192B, a light emitting layer 193B, a buffer layer 194B, and a common electrode 115. The light emitting element 190B has a function of emitting blue light 321B.

[0275] The light emitting element 190G has a pixel electrode 191, a buffer layer 192G, a light emitting layer 193G, a buffer layer 194G, and a common electrode 115. The light emitting element 190G has a function of emitting green light 321G.

[0276] The light emitting / receiving element 190SR has a pixel electrode 191, a buffer layer 192R, an active layer 183, a light emitting layer 193R, a buffer layer 194R, and a common electrode 115. The light emitting / receiving element 190SR has a function of emitting red light 321R and a function of detecting light 322.

[0277] 24A shows a case where the light emitting / receiving element 190SR functions as a light emitting element. In FIG. 24A, an example is shown in which the light emitting element 190B emits blue light, the light emitting element 190G emits green light, and the light emitting / receiving element 190SR emits red light.

[0278] Fig. 24B shows a case where the light emitting / receiving element 190SR functions as a light receiving element. Fig. 24B shows an example in which the light emitting / receiving element 190SR detects blue light emitted by the light emitting element 190B and green light emitted by the light emitting element 190G.

[0279] The pixel electrode 191 is located on the insulating layer 214. The ends of the pixel electrode 191 are covered with a partition wall 216. Two adjacent pixel electrodes 191 are electrically insulated from each other (also referred to as being electrically separated) by the partition wall 216.

[0280] An organic insulating film is suitable for the partition wall 216. 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 216 is a layer that transmits visible light. Instead of the partition wall 216, a partition wall that blocks visible light may be provided.

[0281] The display device 310A has a light emitting / receiving element 190SR, a light emitting element 190G, a light emitting element 190B, a transistor 342, and the like between a pair of substrates (substrate 151 and substrate 152).

[0282] The light receiving / emitting element 190SR has a function of detecting light. Specifically, the light receiving / emitting element 190SR is a photoelectric conversion element that receives light 322 incident from outside the display device 310A and converts it into an electrical signal. The light 322 can also be said to be light emitted by one or both of the light receiving / emitting elements 190G and 190B and reflected by an object. The light 322 may also be incident on the light receiving / emitting element 190SR via a lens.

[0283] The light emitting element 190G and the light emitting element 190B have a function of emitting visible light. Specifically, the light emitting element 190G and the light emitting element 190B are electroluminescent elements that emit light toward the substrate 152 by applying a voltage between the pixel electrode 191 and the common electrode 115 (see light 321G and light 321B).

[0284] The buffer layer 192 (buffer layer 192R, buffer layer 192G, buffer layer 192B), the light-emitting layer 193 (light-emitting layer 193R, light-emitting layer 193G, light-emitting layer 193B), and the buffer layer 194 (buffer layer 194R, buffer layer 194G, buffer layer 194B) can also be called organic layers (layers containing organic compounds) or EL layers. The pixel electrode 191 preferably has a function of reflecting visible light. The common electrode 115 has a function of transmitting visible light.

[0285] The pixel electrode 191 is electrically connected to the source or drain of the transistor 342 through an opening provided in the insulating layer 214. The transistor 342 has a function of controlling the driving of a light-emitting element or a light-emitting and receiving element.

[0286] At least a part of the circuit electrically connected to the light emitting / receiving element 190SR is preferably formed using the same material and in the same process as the circuit electrically connected to the light emitting element 190G and the light emitting element 190B, which allows the display device to be thinner and the manufacturing process to be simplified compared to when the two circuits are formed separately.

[0287] The light emitting / receiving element 190SR, the light emitting element 190G, and the light emitting element 190B are preferably each covered with a protective layer 195. In FIG. 24A and other figures, the protective layer 195 is provided on and in contact with the common electrode 115. Providing the protective layer 195 prevents impurities from entering the light emitting / receiving element 190SR and the light emitting elements of each color, thereby improving the reliability of the light emitting / receiving element 190SR and the light emitting elements of each color. In addition, the protective layer 195 and the substrate 152 are bonded together by the adhesive layer 142.

[0288] A light-shielding layer BM is provided on the surface of the substrate 152 facing the substrate 151. The light-shielding layer BM has openings at positions overlapping with the light-emitting element 190G and the light-emitting element 190B and at a position overlapping with the light-receiving / light-emitting element 190SR. In this specification and the like, the position overlapping with the light-emitting element 190G or the light-emitting element 190B specifically refers to a position overlapping with the light-emitting region of the light-emitting element 190G or the light-emitting element 190B. Similarly, the position overlapping with the light-receiving / light-emitting element 190SR specifically refers to a position overlapping with the light-emitting region and the light-receiving region of the light-receiving / light-emitting element 190SR.

[0289] As shown in FIG. 24B , the light receiving / emitting element 190SR can detect light emitted by the light emitting element 190G or the light emitting element 190B reflected by an object. However, there are cases where the light emitted by the light emitting element 190G or the light emitting element 190B is reflected within the display device 310A and enters the light receiving / emitting element 190SR without passing through the object. The light-shielding layer BM can suppress the influence of such stray light. For example, if the light-shielding layer BM were not provided, the light 323 emitted by the light emitting element 190G would be reflected by the substrate 152, and reflected light 324 would enter the light receiving / emitting element 190SR. By providing the light-shielding layer BM, it is possible to prevent the reflected light 324 from entering the light receiving / emitting element 190SR. This reduces noise and improves the sensitivity of the sensor using the light receiving / emitting element 190SR.

[0290] The light-shielding layer BM can be made of a material that blocks light emitted from the light-emitting element. The light-shielding layer BM preferably absorbs visible light. For example, the light-shielding layer BM 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 BM may have a laminated structure of a red color filter, a green color filter, and a blue color filter.

[0291] [Display device 310B] 25A differs from the display device 310A in that the light emitting element 190G, the light emitting element 190B, and the light emitting / receiving element 190SR do not have the buffer layer 192 and the buffer layer 194, but have the common layer 112 and the common layer 114. In the following description of the display device, description of the same configuration as the display device described above may be omitted.

[0292] The layered structure of the light emitting element 190B, the light emitting element 190G, and the light emitting / receiving element 190SR is not limited to the configuration shown in the display devices 310A and 310B. For example, the layered structures shown in Figures 20 to 23 can be applied to each element as appropriate.

[0293] [Display device 310C] Display device 310C in FIG. 25B differs from display device 310B in that it does not have substrate 151 and substrate 152, but has substrate 153, substrate 154, adhesive layer 155, and insulating layer 212.

[0294] The substrate 153 and the insulating layer 212 are bonded together by an adhesive layer 155. The substrate 154 and the protective layer 195 are bonded together by an adhesive layer 142.

[0295] The display device 310C is fabricated by transferring the insulating layer 212, the transistor 342, the light emitting / receiving element 190SR, the light emitting element 190G, and the light emitting element 190B, which are formed on a fabrication substrate, onto the substrate 153. The substrates 153 and 154 are preferably flexible, which can increase the flexibility of the display device 310C. For example, the substrates 153 and 154 are preferably made of resin.

[0296] Substrates 153 and 154 can be made of polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. One or both of substrates 153 and 154 may be made of glass having a thickness sufficient to provide flexibility.

[0297] The substrate of the display device of this embodiment may be a film having high optical isotropy, such as a triacetyl cellulose (TAC, also called cellulose triacetate) film, a cycloolefin polymer (COP) film, a cycloolefin copolymer (COC) film, or an acrylic film.

[0298] Below, a more detailed configuration of a display device according to one embodiment of the present invention will be described with reference to FIGS.

[0299] [Display device 100A] FIG. 26 shows a perspective view of the display device 100A, and FIG. 27 shows a cross-sectional view of the display device 100A.

[0300] The display device 100A has a configuration in which a substrate 152 and a substrate 151 are bonded together. In Fig. 26, the substrate 152 is indicated by a dashed line.

[0301] The display device 100A has a display unit 162, a circuit 164, wiring 165, etc. Fig. 26 shows an example in which an IC (integrated circuit) 173 and an FPC 172 are mounted on the display device 100A. Therefore, the configuration shown in Fig. 26 can also be said to be a display module having the display device 100A, an IC, and an FPC.

[0302] The circuit 164 can be, for example, a scanning line driver circuit.

[0303] The wiring 165 has a function of supplying signals and power to the display unit 162 and the circuit 164. The signals and power are input to the wiring 165 from the outside via the FPC 172 or input to the wiring 165 from the IC 173.

[0304] 26 shows an example in which an IC 173 is provided on a substrate 151 by a COG (Chip On Glass) method or a COF (Chip on Film) method. The IC 173 may be, for example, an IC having a scanning line driving circuit or a signal line driving circuit. The display device 100A and the display module may be configured without an IC. Alternatively, the IC may be mounted on an FPC by a COF method or the like.

[0305] Figure 27 shows an example of a cross section of the display device 100A shown in Figure 26, with a portion of the area including the FPC 172, a portion of the area including the circuit 164, a portion of the area including the display unit 162, and a portion of the area including the end portion cut away.

[0306] The display device 100A shown in FIG. 27 includes, between a substrate 151 and a substrate 152, a transistor 201, a transistor 205, a transistor 206, a transistor 207, a light-emitting element 190B, a light-emitting element 190G, a light-emitting element 190SR, and the like.

[0307] The substrate 152 and the insulating layer 214 are bonded via an adhesive layer 142. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light emitting element 190B, the light emitting element 190G, and the light receiving / emitting element 190SR. In FIG. 27, a space 143 surrounded by the substrate 152, the adhesive layer 142, and the insulating layer 214 is filled with an inert gas (nitrogen, argon, etc.), and a hollow sealing structure is applied. The adhesive layer 142 may be provided so as to overlap the light emitting element 190B, the light emitting element 190G, and the light receiving / emitting element 190SR. Furthermore, the space 143 surrounded by the substrate 152, the adhesive layer 142, and the insulating layer 214 may be filled with a resin different from the adhesive layer 142.

[0308] The light-emitting element 190B has a layered structure in which a pixel electrode 191, a common layer 112, a light-emitting layer 193B, a common layer 114, and a common electrode 115 are layered in this order from the insulating layer 214 side. The pixel electrode 191 is connected to a conductive layer 222b of the transistor 207 through an opening provided in the insulating layer 214. The transistor 207 has a function of controlling driving of the light-emitting element 190B. An end of the pixel electrode 191 is covered with a partition wall 216. The pixel electrode 191 contains a material that reflects visible light, and the common electrode 115 contains a material that transmits visible light.

[0309] The light-emitting element 190G has a layered structure in which a pixel electrode 191, a common layer 112, a light-emitting layer 193G, a common layer 114, and a common electrode 115 are stacked in this order from the insulating layer 214 side. The pixel electrode 191 is connected to a conductive layer 222b of the transistor 206 through an opening provided in the insulating layer 214. The transistor 206 has a function of controlling driving of the light-emitting element 190G.

[0310] The light emitting / receiving element 190SR has a layered structure in which a pixel electrode 191, a common layer 112, an active layer 183, a light emitting layer 193R, a common layer 114, and a common electrode 115 are layered in this order from the insulating layer 214 side. The pixel electrode 191 is electrically connected to a conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The transistor 205 has a function of controlling the driving of the light emitting / receiving element 190SR.

[0311] Light emitted by the light emitting element 190B, the light emitting element 190G, and the light receiving / emitting element 190SR is emitted toward the substrate 152. Furthermore, light is incident on the light receiving / emitting element 190SR via the substrate 152 and the space 143. It is preferable that the substrate 152 be made of a material that is highly transparent to visible light.

[0312] The pixel electrode 191 can be manufactured using the same material and the same process. The common layer 112, the common layer 114, and the common electrode 115 are commonly used for the light-emitting element 190B, the light-emitting element 190G, and the light-receiving / light-emitting element 190SR. The light-receiving / light-emitting element 190SR has a configuration in which an active layer 183 is added to the configuration of a light-emitting element that emits red light. Furthermore, the light-emitting element 190B, the light-emitting element 190G, and the light-receiving / light-emitting element 190SR can all have a common configuration except for the configurations of the active layer 183 and the light-emitting layers 193 of each color. This makes it possible to add a light-receiving function to the display unit 162 of the display device 100A without significantly increasing the number of manufacturing processes.

[0313] A light-shielding layer BM is provided on the surface of substrate 152 facing substrate 151. The light-shielding layer BM has openings at positions overlapping with light-emitting element 190B, light-emitting element 190G, and light-receiving / light-emitting element 190SR. By providing the light-shielding layer BM, it is possible to control the range in which light is detected by light-receiving / light-emitting element 190SR. Furthermore, by providing the light-shielding layer BM, it is possible to prevent light from being directly incident on light-receiving / light-emitting element 190SR from light-emitting element 190G or light-emitting element 190B without passing through an object. Therefore, a sensor with low noise and high sensitivity can be realized.

[0314] The transistor 201, the transistor 205, the transistor 206, and the transistor 207 are all formed over a substrate 151. These transistors can be manufactured using the same material and through the same process.

[0315] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 151 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 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.

[0316] It is preferable that at least one insulating layer covering the transistor is 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.

[0317] The insulating layer 211, the insulating layer 213, and the insulating layer 215 are preferably formed using an inorganic insulating film. Examples of inorganic insulating films 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. Alternatively, 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, a neodymium oxide film, or the like may be used. Two or more of the above insulating films may be stacked. A base film may be provided between the substrate 151 and the transistor. The above inorganic insulating film may also be used for the base film.

[0318] 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 100A. This can prevent impurities from entering from the edge of the display device 100A through 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 100A, so that the organic insulating film is not exposed at the edge of the display device 100A.

[0319] An organic insulating film is suitable for the insulating layer 214, 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.

[0320] 27, an opening is formed in the insulating layer 214. This makes it possible to prevent impurities from entering the display unit 162 from the outside through the insulating layer 214, even when an organic insulating film is used for the insulating layer 214. This makes it possible to improve the reliability of the display device 100A.

[0321] The transistor 201, the transistor 205, the transistor 206, and the transistor 207 each include a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as a source and a drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0322] 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.

[0323] The transistors 201, 205, 206, and 207 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 transistor. Alternatively, the threshold voltage of the transistor may be controlled by supplying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0324] The crystallinity of the semiconductor material used for the transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystal semiconductor, and a semiconductor having crystallinity other than single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single-crystal semiconductor or a crystalline semiconductor is preferable because it can suppress deterioration of the transistor characteristics.

[0325] 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).

[0326] The semiconductor layer preferably contains, for example, indium, M (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.

[0327] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) for the semiconductor layer. Alternatively, it is preferable to use an oxide containing indium, gallium, zinc, and tin. Alternatively, it is preferable to use an oxide containing indium and zinc.

[0328] 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 In:M:Zn=1:1:1 or a composition thereabout, In:M:Zn=1:1:1.2 or a composition thereabout, In:M:Zn=2:1:3 or a composition thereabout, In:M:Zn=3:1:2 or a composition thereabout, In:M:Zn=4:2:3 or a composition thereabout, In:M:Zn=4:2:4.1 or a composition thereabout, In:M:Zn=5:1:3 or a composition thereabout, In:M:Zn=5:1:6 or a composition thereabout, In:M:Zn=5:1:7 or a composition thereabout, In:M:Zn=5:1:8 or a composition thereabout, In:M:Zn=10:1:3 or a composition thereabout, In:M:Zn=6:1:6 or a composition thereabout, and In:M:Zn=5:2:5 or a composition thereabout. The term "nearby composition" includes a range of ±30% of the desired atomic ratio.

[0329] 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.

[0330] The transistors included in the circuit 164 may have the same structure as or different from the transistors included in the display portion 162. The transistors included in the circuit 164 may all have the same structure or may have two or more types of structures. Similarly, the transistors included in the display portion 162 may all have the same structure or may have two or more types of structures.

[0331] A connection section 204 is provided in an area of ​​the substrate 151 where the substrate 152 does not overlap. In the connection section 204, the wiring 165 is electrically connected to the FPC 172 via a conductive layer 166 and a connection layer 242. The conductive layer 166, which is obtained by processing the same conductive film as the pixel electrode 191, is exposed on the upper surface of the connection section 204. This allows the connection section 204 and the FPC 172 to be electrically connected via the connection layer 242.

[0332] Various optical members can be disposed on the outside of the substrate 152. 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 anti-static film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses scratches caused by use, an impact absorbing layer, etc. may be disposed on the outside of the substrate 152.

[0333] The substrate 151 and the substrate 152 can each be made of glass, quartz, ceramic, sapphire, resin, etc. Using a flexible material for the substrate 151 and the substrate 152 can increase the flexibility of the display device.

[0334] 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.

[0335] The connection layer may be made of an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0336] 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.

[0337] 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 for conductive layers such as various wirings and electrodes constituting a display device, conductive layers (conductive layers functioning as pixel electrodes or common electrodes) of light-emitting elements and light-emitting / receiving elements, and the like.

[0338] 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.

[0339] [Display device 100B] FIG. 28A shows a cross-sectional view of the display device 100B.

[0340] The display device 100B differs from the display device 100A mainly in that it has a protective layer 195. Detailed descriptions of the same configuration as the display device 100A will be omitted.

[0341] By providing a protective layer 195 that covers the light-emitting element 190B, the light-emitting element 190G, and the light-receiving / light-emitting element 190SR, it is possible to prevent impurities such as water from entering the light-emitting element 190B, the light-emitting element 190G, and the light-receiving / light-emitting element 190SR, thereby improving the reliability of the light-emitting element 190B, the light-emitting element 190G, and the light-receiving / light-emitting element 190SR.

[0342] In a region 228 near the edge of the display device 100B, it is preferable that the insulating layer 215 and the protective layer 195 contact each other through the opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating film of the insulating layer 215 and the inorganic insulating film of the protective layer 195 contact each other. This makes it possible to prevent impurities from entering the display unit 162 from the outside through the organic insulating film. This can therefore improve the reliability of the display device 100B.

[0343] The protective layer 195 may have a single layer or a multilayer structure, and may have, for example, a three-layer structure including an inorganic insulating layer on the common electrode 115, an organic insulating layer on the inorganic insulating layer, and an inorganic insulating layer on the organic insulating layer. In this case, it is preferable that the end of the inorganic insulating layer extends further outward than the end of the organic insulating layer.

[0344] Furthermore, a lens may be provided in the area overlapping with the light emitting / receiving element 190SR, thereby improving the sensitivity and accuracy of the sensor using the light emitting / receiving element 190SR.

[0345] The lens preferably has a refractive index of 1.3 or more and 2.5 or less. The lens can be formed using at least one of an inorganic material and an organic material. For example, a material containing a resin can be used for the lens. Also, a material containing at least one of an oxide and a sulfide can be used for the lens.

[0346] Specifically, resins containing chlorine, bromine, or iodine, resins containing heavy metal atoms, resins containing aromatic rings, resins containing sulfur, etc. can be used for the lenses. Alternatively, materials containing resin and nanoparticles of a material with a higher refractive index than the resin can be used for the lenses. Titanium oxide or zirconium oxide can be used for the nanoparticles.

[0347] In addition, cerium oxide, hafnium oxide, lanthanum oxide, magnesium oxide, niobium oxide, tantalum oxide, titanium oxide, yttrium oxide, zinc oxide, oxides containing indium and tin, or oxides containing indium, gallium, and zinc can be used for the lens. Alternatively, zinc sulfide can be used for the lens.

[0348] In the display device 100B, the protective layer 195 and the substrate 152 are bonded together by an adhesive layer 142. The adhesive layer 142 is provided to overlap the light-emitting element 190B, the light-emitting element 190G, and the light-receiving / light-emitting element 190SR, respectively, and a solid sealing structure is applied to the display device 100B.

[0349] [Display device 100C] FIG. 29A shows a cross-sectional view of the display device 100C.

[0350] The display device 100C differs from the display device 100B in the structure of the transistors.

[0351] The display device 100C includes a transistor 208, a transistor 209, and a transistor 210 over a substrate 151.

[0352] The transistor 208, the transistor 209, and the transistor 210 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a semiconductor layer including a channel formation region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 functioning as a gate insulating layer, a conductive layer 223 functioning as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located between the conductive layer 223 and the channel formation region 231i.

[0353] The conductive layer 222a and the conductive layer 222b are connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215, respectively. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0354] The pixel electrode 191 of the light emitting element 190G is electrically connected to one of a pair of low resistance regions 231n of the transistor 208 via the conductive layer 222b.

[0355] The pixel electrode 191 of the light emitting / receiving element 190SR is electrically connected to the other of the pair of low resistance regions 231n of the transistor 209 via the conductive layer 222b.

[0356] 29A shows an example in which the insulating layer 225 covers the top and side surfaces of the semiconductor layer. On the other hand, in the transistor 202 shown in FIG. 29B, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 but does not overlap with the low-resistance region 231n. For example, the structure shown in FIG. 29B can be manufactured by processing the insulating layer 225 using the conductive layer 223 as a mask. In FIG. 29B, the insulating layer 215 is provided to cover the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through openings in the insulating layer 215. Furthermore, an insulating layer 218 may be provided to cover the transistor.

[0357] The display device 100C also differs from the display device 100B in that it does not have the substrate 151 and the substrate 152, but has the substrate 153, the substrate 154, the adhesive layer 155, and the insulating layer 212.

[0358] The substrate 153 and the insulating layer 212 are bonded together by an adhesive layer 155. The substrate 154 and the protective layer 195 are bonded together by an adhesive layer 142.

[0359] The display device 100C is fabricated by transferring the insulating layer 212, the transistor 208, the transistor 209, the transistor 210, the light-emitting element 190SR, the light-emitting element 190G, and the like, which are formed on a fabrication substrate, onto a substrate 153. The substrate 153 and the substrate 154 are preferably flexible, which can increase the flexibility of the display device 100C.

[0360] The insulating layer 212 can be formed using the inorganic insulating film that can be used for the insulating layers 211, 213, and 215.

[0361] As described above, in the display device of this embodiment, a light-receiving / light-emitting element is provided in each sub-pixel that exhibits one of the colors instead of a light-emitting element. The light-receiving / light-emitting element functions as both a light-emitting element and a light-receiving element, so that the pixel can be given a light-receiving function without increasing the number of sub-pixels included in the pixel. Furthermore, the pixel can be given a light-receiving function without reducing the resolution of the display device or the aperture ratio of each sub-pixel.

[0362] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0363] (Embodiment 3) In this embodiment, a metal oxide (also referred to as an oxide semiconductor) that can be used for the OS transistor described in the above embodiment will be described.

[0364] 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.

[0365] 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.

[0366] <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.

[0367] 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.

[0368] 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.

[0369] 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.

[0370] <<Oxide semiconductor structure>> 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.

[0371] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0372] [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.

[0373] 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.

[0374] 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.

[0375] 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.

[0376] 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).

[0377] 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.

[0378] 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.

[0379] CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by impurities or defects, the CAAC-OS can 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 budgets) during the manufacturing process. Therefore, using a CAAC-OS for an OS transistor can increase the flexibility of the manufacturing process.

[0380] [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 system, 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.

[0381] [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.

[0382] <<Oxide semiconductor structure>> Next, the above-mentioned CAC-OS will be described in detail, which relates to the material composition.

[0383] [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.

[0384] 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.

[0385] 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.

[0386] 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.

[0387] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0388] 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.

[0389] The CAC-OS can be formed, for example, by a sputtering method under conditions where the substrate is not intentionally heated. When the CAC-OS is formed by a sputtering method, any 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.

[0390] 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.

[0391] 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).

[0392] 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.

[0393] 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.

[0394] Furthermore, a transistor using CAC-OS has high reliability, making it ideal for various semiconductor devices such as display devices.

[0395] 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.

[0396] <Transistors containing oxide semiconductors> Next, a case where the oxide semiconductor is used in a transistor will be described.

[0397] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0398] 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.

[0399] 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.

[0400] 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.

[0401] 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.

[0402] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0403] 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.

[0404] 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:

[0405] 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 or equal to 1×10 18 atoms / cm 3 Less than 5 × 10, more preferably 17 atoms / cm 3 Do the following:

[0406] 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.

[0407] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0408] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0409] (Fourth embodiment) In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0410] The electronic devices of this embodiment include the display device of one embodiment of the present invention. For example, the display device of one embodiment of the present invention can be applied to a display portion of an electronic device. The display device of one embodiment of the present invention has a function of detecting light, and therefore, can perform biometric authentication on the display portion, detect a touch operation (contact or approach), and the like. This can improve the functionality, convenience, and the like of the electronic device.

[0411] Examples of electronic devices include electronic devices with relatively large screens such as television sets, desktop or notebook personal computers, computer monitors, digital signage, 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 playback devices.

[0412] The electronic device of this embodiment may have a sensor (including a function to measure 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).

[0413] The electronic device of the present embodiment can have various functions, such as 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, time, etc., a function to execute various software (programs), a wireless communication function, a function to read out programs or data recorded on a recording medium, etc.

[0414] Electronic device 6500 shown in FIG. 30A is a portable information terminal that can be used as a smartphone.

[0415] 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.

[0416] The display device of one embodiment of the present invention can be applied to the display portion 6502.

[0417] FIG. 30B is a schematic cross-sectional view including the end of the housing 6501 on the microphone 6506 side.

[0418] 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.

[0419] 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).

[0420] 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.

[0421] 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.

[0422] When the display device of one embodiment of the present invention is used 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 and fingerprint authentication can be performed.

[0423] 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.

[0424] 31A 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.

[0425] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0426] 31A 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.

[0427] 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.

[0428] 31B 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.

[0429] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0430] 31C and 31D show an example of digital signage.

[0431] 31C 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.

[0432] 31D 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.

[0433] 31C and 31D, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0434] 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.

[0435] 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.

[0436] 31C and 31D, 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.

[0437] 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.

[0438] The electronic device shown in Figures 32A to 32F 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.

[0439] The electronic devices shown in Figures 32A to 32F 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 to capture still images, videos, etc. and store them on a recording medium (external or built-in to the camera), and may have a function to display the captured images on the display unit, etc.

[0440] The electronic devices shown in FIGS. 32A to 32F will be described in detail below.

[0441] FIG. 32A 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. 32A 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, and the like, the titles of emails, SNS messages, and the like, 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.

[0442] 32B 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.

[0443] 32C 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 charging with other information terminals through a connection terminal 9006. Charging may be performed by wireless power supply.

[0444] 32D to 32F are perspective views showing a foldable mobile information terminal 9201. FIG. 32D shows the mobile information terminal 9201 in an unfolded state, FIG. 32F shows it in a folded state, and FIG. 32E is a perspective view showing a state in the process of changing from one of FIG. 32D and FIG. 32F to the other. The mobile information terminal 9201 is highly portable when folded, and has a seamless, wide display area when unfolded, providing excellent viewability of the display. 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.

[0445] 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]

[0446] SA: Light-emitting / receiving element: Tr1-Tr2: Transistors: SW1-SW4: Switches: CS1-CS2: Capacitor: SL: Wiring: WX: Wiring: AL: Wiring: CL: Wiring: VCP: Wiring: VPI: Wiring: VL1: Wiring: SR: Light-emitting / receiving element: ELG: Light-emitting element: ELB: Light-emitting element: M1-M3: Transistors: M10-M14: Transistors: C1-C2: Capacitor: GL: Wiring: TX: Wiring: SE: Wiring: RS: Wiring: REN: Wiring: SL1-SL3: Wiring: V0L: Wiring: 10: Display device: 11: Display unit: 12: Drive circuit unit: 13: Drive circuit unit: 14: Drive circuit unit: 15: Circuit unit: 20B: Sub-pixel: 20G: Sub-pixel: 20R: Sub-pixel: 21B: Circuit: 21G: Circuit: 21R: Circuit: 22: Circuit: 30: Pixel: 30B: Pixel: 30G: Pixel

Claims

[Claim 1] a first to fourth switches, a first transistor, a second transistor, a capacitance, a first wiring, a second wiring, and a light emitting / receiving element; the first switch has one electrode electrically connected to the first wiring and the other electrode electrically connected to the gate of the first transistor and one electrode of the capacitor; the second switch has one electrode electrically connected to one of the source and drain of the first transistor, one electrode of the light emitting / receiving element, and the other electrode of the capacitor, and the other electrode electrically connected to the gate of the second transistor and one electrode of the third switch; the third switch has the other electrode electrically connected to the second wiring, the fourth switch has one electrode electrically connected to one electrode of the second switch and the other electrode electrically connected to one electrode of the light emitting / receiving element; The light emitting / receiving element has a function of emitting light of a first color and a function of receiving light of a second color.

Images