Display device, display module, and electronic device

Abstract

Provided is a display device having an imaging function. Further provided is a high-resolution imaging device or display device. The display device comprises first to fourth switches, a first transistor, a capacitor, and a light-receiving / emitting element. The first switch is connected to the gate of the first transistor. The second switch is connected to one of the source and drain of the first transistor. The light-receiving / emitting element has an anode that is connected to the other of the source and drain of the first transistor via a third switch. The fourth switch is connected to the other of the source and drain of the first transistor. The capacitor has one electrode connected to the gate of the first transistor, and another electrode connected to the other of the source and drain of the first transistor. The light-receiving / emitting element emits light of a first color and receives light of a second color, and converts the light to an electrical signal.

Description

Technical Field

[0001] One aspect of the present invention relates to a display device. One aspect of the present invention relates to an imaging device. One aspect of the present invention relates to a display device having an imaging function.

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

Background Art

[0003] In recent years, display devices have been required to have higher definition in order to display high-resolution images. In addition, in information terminal devices such as smartphones, tablet terminals, and notebook PCs (personal computers), display devices are required to consume less power in addition to higher definition. Furthermore, there is a demand for display devices with various functions added, such as a function as a touch panel and a function of imaging fingerprints for authentication, in addition to displaying images.

[0004] As a display device, for example, a light-emitting device having a light-emitting element has been developed. A light-emitting element (also referred to as an EL element) that utilizes the electroluminescence (hereinafter abbreviated as EL) phenomenon has characteristics such as being easily thinned and lightened, being able to respond quickly to an input signal, and being drivable using a DC constant voltage power supply, and has been applied to display devices. For example, Patent Document 1 discloses a flexible light-emitting device to which an organic EL element is applied.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] One aspect of the present invention is to provide a display device having an imaging function as one of the problems. One aspect of the present invention is to provide an imaging device or a display device having a high-definition display unit or imaging unit as one of the problems. One aspect of the present invention is to provide an imaging device or a display device capable of imaging a high-definition image as one of the problems. One aspect of the present invention is to provide an imaging device or a display device capable of performing high-sensitivity imaging as one of the problems. One aspect of the present invention is to provide a display device capable of acquiring biometric information such as fingerprints as one of the problems. One aspect of the present invention is to provide a display device that functions as a touch panel as one of the problems.

[0007] Also, one aspect of the present invention is to reduce the number of components of an electronic device as one of the problems. One aspect of the present invention is to provide a display device, an imaging device, or an electronic device having a novel configuration as one of the problems. One aspect of the present invention is to reduce at least one of the problems of the prior art as one of the problems.

[0008] Note that the description of these problems does not prevent the existence of other problems. Note that one aspect of the present invention does not need to solve all of these problems. Note that other problems can be extracted from the descriptions of the specification, drawings, claims, etc.

Means for Solving the Problems

[0009] One aspect of the present invention is a display device including a first to third switches, a first transistor, a capacitor, a light emitting and receiving element, and first to third wirings. The first wiring is electrically connected to the gate of the first transistor via the first switch. The second wiring is electrically connected to one of the source and drain of the first transistor via the second switch. The anode of the light emitting and receiving element is electrically connected to the other of the source and drain of the first transistor via the third switch, and the cathode is electrically connected to the third wiring. One electrode of the capacitor is electrically connected to the gate of the first transistor, and the other electrode is electrically connected to the other of the source and drain of the first transistor. A first potential is applied to the second wiring, a second potential lower than the first potential is applied to the third wiring, and the light emitting and receiving element has a function of emitting light of a first color and a function of receiving light of a second color and converting it into an electrical signal.

[0010] One aspect of the present invention is a display device including a first to fourth switches, a first transistor, a capacitor, a light emitting and receiving element, and first to fourth wirings. The first wiring is electrically connected to the gate of the first transistor via the first switch. The second wiring is electrically connected to one of the source and drain of the first transistor via the second switch. The anode of the light emitting and receiving element is electrically connected to the other of the source and drain of the first transistor via the third switch, and the cathode is electrically connected to the third wiring. The fourth wiring is electrically connected to the other of the source and drain of the first transistor via the fourth switch. One electrode of the capacitor is electrically connected to the gate of the first transistor, and the other electrode is electrically connected to the other of the source and drain of the first transistor. A first potential is applied to the second wiring, a second potential lower than the first potential is applied to the third wiring. The light emitting and receiving element has a function of emitting light of a first color and a function of receiving light of a second color and converting it into an electrical signal.

[0011] Also, in the above, in the first period, the first to fourth switches are in a conductive state, it is preferable that a data potential is applied to the first wiring, and a third potential is applied to the fourth wiring. Further, in the second period, the first to fourth switches are preferably in a non-conductive state.

[0012] Also, in any of the above, in the third period, the first switch, the third switch, and the fourth switch are in a conductive state, the second switch is in a non-conductive state, a fourth potential lower than the first potential is applied to the first wiring, and it is preferable that a fifth potential lower than the second potential is applied to the fourth wiring. Further, in the fourth period, the first switch and the third switch are in a conductive state, the second switch and the fourth switch are in a non-conductive state, and it is preferable that a sixth potential higher than the second potential is applied to the first wiring. Further, in the fifth period, the first switch and the third switch are preferably in a non-conductive state, and the second switch and the fourth switch are in a conductive state.

[0013] Another aspect of the present invention is a display device having a first to fifth transistors, a capacitor, a light-emitting and light-receiving element, and first to fourth wirings. One of the source and drain of the second 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 the source and drain of the third transistor is electrically connected to the second wiring, and the other of the source and drain is electrically connected to one of the source and drain of the first transistor. One of the source and drain of the fourth transistor is electrically connected to the other of the source and drain of the first transistor, and the other of the source and drain is electrically connected to the anode of the light-emitting and light-receiving element. The cathode of the light-emitting and light-receiving element is electrically connected to the third wiring. One of the source and drain of the fifth transistor is electrically connected to the other of the source and drain of the first transistor, and the other of the source and drain is electrically connected to the fourth wiring. One electrode of the capacitor is electrically connected to the gate of the first transistor, and the other electrode is electrically connected to the other of the source and drain of the first transistor. A first potential is applied to the second wiring, and a second potential lower than the first potential is applied to the third wiring. The light-emitting and light-receiving element has a function of emitting light of a first color and a function of receiving light of a second color and converting it into an electrical signal.

[0014] Also, in the above, it is preferable that one or more of the first to fifth transistors have a gate and a back gate, and the same potential is applied to the gate and the back gate.

[0015] Also, in the above, it is preferable to have a light-emitting element having a function of emitting light of a second color. At this time, it is more preferable that the light-emitting and light-receiving element and the light-emitting element are provided on the same plane.

[0016] In addition, in the above, it is preferable that the light-receiving and emitting element has a first pixel electrode, a first light-emitting layer, an active layer, and a first electrode. Further, it is preferable that the light-emitting element has a second pixel electrode, a second light-emitting layer, and a first electrode. At this time, the first pixel electrode and the second pixel electrode are preferably formed by processing the same conductive film.

[0017] Another aspect of the present invention is a display module including any one of the above display devices and a connector or an integrated circuit.

[0018] Another aspect of the present invention is an electronic device including the above 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.

Advantages of the Invention

[0019] According to one aspect of the present invention, a display device having an imaging function can be provided. Alternatively, an imaging device or a display device having a display unit or an imaging unit can be provided. Alternatively, an imaging device or a display device capable of capturing a high-definition image can be provided. Alternatively, an imaging device or a display device capable of performing high-sensitivity imaging can be provided. Alternatively, a display device capable of acquiring biometric information such as fingerprints can be provided. Alternatively, a display device functioning as a touch panel can be provided.

[0020] In addition, according to one aspect of the present invention, the number of components of an electronic device can be reduced. Alternatively, a display device, an imaging device, or an electronic device having a novel configuration can be provided. Alternatively, at least one of the problems of the prior art can be at least alleviated.

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

Brief Description of the Drawings

[0022] FIG. 1 is a circuit diagram showing an example of a pixel. FIGS. 2A and 2B are diagrams for explaining an example of an operation method of a pixel circuit. FIGS. 3A to 3D are diagrams for explaining an example of an operation method of a pixel circuit. FIG. 4A is a circuit diagram showing an example of a pixel. FIGS. 4B and 4C are diagrams for explaining an example of an operation method of a pixel circuit. FIGS. 5A to 5E are diagrams for explaining an example of an operation method of a pixel circuit. FIG. 6 is a diagram showing an example of a display device. FIG. 7 is a circuit diagram showing an example of a pixel. FIG. 8A is a circuit diagram showing an example of a pixel, and FIG. 8B is a circuit diagram of a transistor. FIG. 9 is a circuit diagram showing an example of a pixel. FIGS. 10A and 10B are diagrams showing an example of a display device. FIG. 11 is a circuit diagram showing an example of a pixel. FIG. 12 is a diagram for explaining an example of an operation method of a display device. FIG. 13 is a diagram for explaining an example of an operation method of a display device. FIGS. 14A to 14D are cross-sectional views showing an example of a display device. FIGS. 14E to 14G are top views showing an example of a pixel. FIGS. 15A to 15D are top views showing an example of a pixel. FIGS. 16A to 16E are cross-sectional views showing an example of a light-emitting and receiving element. FIGS. 17A and 17B are cross-sectional views showing an example of a display device. FIGS. 18A and 18B are cross-sectional views showing an example of a display device. FIGS. 19A and 19B are cross-sectional views showing an example of a display device. FIGS. 20A and 20B are cross-sectional views showing an example of a display device. FIGS. 21A and 21B are cross-sectional views showing an example of a display device. FIG. 22 is a perspective view showing an example of a display device. FIG. 23 is a cross-sectional view showing an example of a display device. FIG. 24 is a cross-sectional view showing an example of a display device. FIG. 25A is a cross-sectional view showing an example of a display device. FIG. 25B is a cross-sectional view showing an example of a transistor. FIGS. 26A and 26B are diagrams showing an example of an electronic device. FIGS. 27A to 27D are diagrams showing an example of an electronic device. FIGS. 28A to 28F are diagrams showing an example of an electronic device.

Embodiments for Carrying Out the Invention

[0023] Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments can be implemented in many different ways, and it will be easily understood by those skilled in the art that the forms and details can be variously changed without departing from the spirit and scope thereof. Therefore, the present invention should not be construed as being limited to the description of the following embodiments.

[0024] In the configuration of the invention described below, the same reference numerals are commonly used among different drawings for the same part or parts having the same function, and the repeated description thereof will be omitted. In addition, when referring to the same function, the hatch patterns may be the same, and there may be cases where no reference numerals are particularly assigned.

[0025] In each of the drawings described in this specification, the sizes of the respective components, the thicknesses of the layers, or the regions may be exaggerated for clarity. Therefore, it is not necessarily limited to that scale.

[0026] Note that the ordinal numbers such as "first" and "second" in this specification and the like are given to avoid confusion of the components, and are not numerically limiting.

[0027] A transistor is a type of semiconductor device and can realize operations such as amplification of current or voltage and switching operations for controlling conduction or non-conduction. The transistors in this specification include IGFETs (Insulated Gate Field Effect Transistors) and thin film transistors (TFTs: Thin Film Transistors).

[0028] In addition, the functions of the "source" and "drain" may be interchanged when transistors with different polarities are adopted, or when the direction of current changes during circuit operation. Therefore, in this specification, the terms "source" and "drain" are assumed to be interchangeable.

[0029] In addition, in this specification and the like, "electrically connected" includes cases where connection is made through "something having some electrical effect". Here, "something having some electrical effect" is not particularly limited as long as it enables the exchange of electrical signals between the connection targets. For example, "something having some electrical effect" includes electrodes, wirings, switching elements such as transistors, resistance elements, coils, capacitance elements, and other elements having various functions.

[0030] In this specification and the like, a node refers to an element (such as a wiring) that enables electrical connection of elements constituting a circuit. Therefore, the "node to which A is connected" refers to a wiring that is electrically connected to A and can be regarded as having the same potential as A. Note that even if one or more elements (such as switches, transistors, capacitance elements, inductors, resistance elements, diodes, etc.) that enable electrical connection are arranged in the middle of the wiring, if it can be regarded as having the same potential as A, that wiring is the node to which A is connected.

[0031] 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 laminate containing the light-emitting layer.

[0032] In this specification and the like, a display panel, which is one aspect of a display device, has a function of displaying (outputting) an image or the like on a display surface. Therefore, the display panel is one aspect of an output device.

[0033] In addition, in this specification and the like, a display panel substrate with a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) attached thereto, or a substrate with an IC mounted thereon by a COG (Chip On Glass) method or the like may be referred to as a display panel module, a display module, or simply a display panel.

[0034] Note that in this specification and the like, a touch panel, which is an 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, presses, or approaches a detection object such as a finger or a stylus on the display surface. Therefore, the touch panel is an aspect of an input / output device.

[0035] The touch panel can also be referred to as, for example, a display panel (or display device) with a touch sensor, or a display panel (or display device) with a touch sensor function. The touch panel can also be configured to include a display panel and a touch sensor panel. Alternatively, it can be configured to have a function as a touch sensor inside or on the surface of the display panel.

[0036] In addition, in this specification and the like, a touch panel substrate with a connector, an IC, etc. mounted thereon may be referred to as a touch panel module, a display module, or simply a touch panel.

[0037] (Embodiment 1) In this embodiment, a configuration example and a driving method example of a display device according to an aspect of the present invention will be described.

[0038] One aspect of the present invention is a display device having a plurality of pixels arranged in a matrix. Each pixel has one or more sub-pixels. Each sub-pixel has one or more light-emitting and receiving elements.

[0039] A light-emitting and light-receiving element (light-emitting and light-receiving device) is an element that combines the function of a light-emitting element (also referred to as a light-emitting device) that emits light of a first color and the function of a photoelectric conversion element (also referred to as a photoelectric conversion device) that receives light of a second color and converts it into an electrical signal. The light-emitting and light-receiving element can also be called a multifunctional element, a multifunctional diode, a light-emitting photodiode, or a bidirectional photodiode, etc.

[0040] By arranging a plurality of sub-pixels having light-emitting and light-receiving elements in a matrix, the display device can have both the function of displaying an image and the function of imaging. Therefore, the display device can also be called a composite device or a multifunctional device.

[0041] [Configuration Example 1] FIG. 1 shows a part of a pixel circuit applicable to a sub-pixel having a light-emitting and light-receiving element. The pixel circuit has switches SW1, SW2, SW3, SW4, a transistor Tr1, and a light-emitting and light-receiving element SA. The pixel circuit preferably has a capacitor CS as a capacitor for holding charges. Further, wirings SL, AL, CL, and WX are connected to the pixel circuit.

[0042] Switches SW1, SW2, SW3, and SW4 each have two terminals (electrodes) and are elements capable of controlling conduction and non-conduction between the terminals.

[0043] The wiring SL is electrically connected to the gate of the transistor Tr1 via the switch SW1. The wiring AL is electrically connected to one of the source and drain of the transistor Tr1 via the switch SW2. The anode of the light emitting and receiving element SA is electrically connected to the other of the source and drain of the transistor Tr1 via the switch SW3. The cathode of the light emitting and receiving element SA is electrically connected to the wiring CL. The wiring WX is electrically connected to the other of the source and drain of the transistor Tr1 via the switch SW4. One of the pair of electrodes of the capacitor CS is electrically connected to the gate of the transistor Tr1, and the other is electrically connected to the other of the source and drain of the transistor Tr1.

[0044] In FIG. 1, the anode of the light emitting and receiving element SA is configured to be located on the transistor Tr1 side. At this time, the potential applied to the wiring CL can be set lower than the potential applied to the wiring AL. Note that the cathode of the light emitting and receiving element SA may be configured to be located on the transistor Tr1 side, and in this case, the wiring CL can be configured to have a potential higher than that of the wiring AL.

[0045] In addition, in FIG. 1 and the like, an example in which an n-channel type transistor is used as the transistor is shown, but a p-channel type transistor can also be applied to part or all of them. At this time, various potentials, signals, etc. may be appropriately changed according to the type of the transistor.

[0046] The transistor Tr1 has a function of controlling the current flowing through the light emitting and receiving element SA. That is, the transistor Tr1 has a function as a driving transistor. The transistor Tr1 can control the current flowing through the light emitting and receiving element SA according to the potential (data potential) applied from the wiring SL via the switch SW1. The light emitting and receiving element SA can emit light with a luminance corresponding to the current.

[0047] Further, the transistor Tr1 has a function as a readout transistor that outputs a signal based on the exposure state of the light-emitting and light-receiving element SA. Specifically, a predetermined potential is applied to the gate of the transistor Tr1, and a potential based on the charge received and generated by the light-emitting and light-receiving element SA is applied to the source. Thus, the conductive state of the transistor Tr1 changes according to the voltage between the gate and the source. Information on the exposure state of the light-emitting and light-receiving element SA can be obtained from the wiring AL to the wiring WX by the current flowing through the transistor Tr1. The wiring WX also functions as a readout wiring.

[0048] In this way, by using a single transistor Tr1 to serve as both the drive transistor when the light-emitting and light-receiving element SA is a light-emitting element and the readout transistor when it is a light-receiving element, the circuit configuration of the pixel circuit can be simplified. Also, along with reducing one transistor, wirings for supplying signals to the transistor can be reduced.

[0049] Furthermore, the capacitor CS functions not only as a holding capacitor when the light-emitting and light-receiving element SA is a light-emitting element but also as a holding capacitor when it is a light-receiving element.

[0050] In this way, by configuring the transistor and the capacitor to have multiple functions, it becomes possible to reduce the occupied area of the pixel and realize a display device with high definition. Therefore, not only can an image with high display quality be displayed, but also a high-definition image can be captured.

[0051] Hereinafter, the operation method of the pixel circuit illustrated in FIG. 1 will be described.

[0052] First, with reference to FIGS. 2A and 2B, an example of the operation method when the light-emitting and light-receiving element SA is used as a light-emitting element will be described.

[0053] FIG. 2A shows that a data potential V is applied to the gate of the transistor Tr1 dataIt schematically shows the operation during the period of writing (data writing period). During the data writing period, all of switch SW1, switch SW2, switch SW3, and switch SW4 are set to the conducting state.

[0054] During the data writing period, as shown by one of the dashed arrows, the gate of transistor Tr1 is supplied with the data potential V from the wiring SL via switch SW1. data Also, as shown by the other dashed arrow, the other of the source and drain of transistor Tr1 is supplied with the potential V0 from the wiring WX via switch SW4. At this time, the capacitor CS1 is charged with a voltage corresponding to the potential difference between the data potential V data and the potential V0.

[0055] Figure 2B schematically shows the operation during the period (holding and light-emitting period) when the gate potential of transistor Tr1 is held and the light-emitting and receiving element SA emits light according to the current flowing through transistor Tr1. During the holding and light-emitting period, switch SW1 and switch SW4 are set to the non-conducting state, and switch SW2 and switch SW3 are set to the conducting state. As a result, almost all of the current flowing through transistor Tr1 flows through the light-emitting and receiving element SA. In Figure 2B, the current path is shown by a dashed arrow.

[0056] Subsequently, with reference to FIGS. 3A to 3D, an example of the operation method when the light-emitting and receiving element SA is used as a light-receiving element will be described.

[0057] Figure 3A schematically shows the operation during the period (reset period) of initializing the potential of the anode of the light-emitting and receiving element SA. During the reset period, switch SW1, switch SW3, and switch SW4 are set to the conducting state, and switch SW2 is set to the non-conducting state.

[0058] During the reset period, as shown by one of the dashed arrows, the anode of the light-emitting and receiving element SA is supplied with the potential V from the wiring WX via switch SW4 and switch SW3. RS Also, the other electrode of the capacitor CS is also supplied with the potential V via switch SW4. RSis applied. The potential V RS shall be lower than at least the potential applied to the wiring CL. The potential V RS is preferably lower than the potential V0.

[0059] In the case of a configuration in which the cathode of the light-emitting and receiving element SA is connected to the transistor Tr1 side, the potential V RS shall be higher than the potential applied to the wiring CL (the potential applied to the anode of the light-emitting and receiving element SA). Also, the potential V RS shall be higher than the potential V0.

[0060] Also, during the reset period, it is preferable that the node to which the gate of the transistor Tr1 is connected is not in a floating state but in a state where a predetermined potential is applied. For example, in FIG. 3A, to the gate of the transistor Tr1 and one electrode of the capacitor CS, the potential V off is applied via the switch SW1 from the wiring SL. The potential V off shall be lower than the potential applied to the wiring AL.

[0061] Also, the potential V off is preferably a potential that turns the transistor Tr1 off. For example, it can be a potential lower than the potential obtained by adding the threshold voltage of the transistor Tr1 to the potential V RS . In particular, the potential V off is preferably lower than the potential V RS .

[0062] FIG. 3B schematically shows the operation during the period (exposure period) in which the light-emitting and receiving element SA receives light and charges are accumulated in the light-emitting and receiving element. During the exposure period, as charges are accumulated in the light-emitting and receiving element SA, the potential difference Vc between the anode and cathode of the light-emitting and receiving element SA changes.

[0063] During the exposure period, all of the switches SW1, SW2, SW3, and SW4 are turned off. The switch SW2 is off, and further, to the gate of the transistor Tr1, the potential Voff Since the given state is maintained, transistor Tr1 also becomes non-conductive. Further, since switch SW3 is in the non-conductive state, there are two non-conductive switches and one non-conductive transistor between wiring AL and light-emitting and receiving element SA. Further, there are also two non-conductive switches (switch SW3 and switch SW4) between wiring WX and light-emitting and receiving element SA. As a result, it is possible to suitably prevent the charge accumulated on the anode side of light-emitting and receiving element SA from flowing out to wiring AL, wiring WX, etc. As a result, highly accurate imaging can be performed by light-emitting and receiving element SA.

[0064] FIG. 3C schematically shows the operation during the period (transfer period) in which the charge accumulated in light-emitting and receiving element SA is transferred to the node to which the source of transistor Tr1 is connected. During the transfer period, switch SW1 and switch SW3 are set to the conductive state, and switch SW2 and switch SW4 are set to the non-conductive state.

[0065] During the transfer period, as shown by one of the dashed arrows, the charge accumulated in light-emitting and receiving element SA is transferred via switch SW3 to the node to which the source of transistor Tr1 and the other electrode of capacitor CS are connected. Let the potential of the node when the transfer is completed be V sig be.

[0066] Also, during the transfer period, as shown by the other dashed arrow, a potential V is applied from wiring SL via switch SW1 to the node to which the gate of transistor Tr1 and one electrode of capacitor CS are connected. gp is applied.

[0067] After the charging of capacitor CS is completed, by setting switch SW1 and switch SW3 to the non-conductive state, the potential of the gate and the potential of the source of transistor Tr1 are maintained.

[0068] FIG. 3D schematically shows the operation during the period (readout period) when data is output from the pixel circuit to the wiring WX. During the readout period, the switches SW1 and SW3 are turned off, and the switches SW2 and SW4 are turned on.

[0069] During the readout period, the gate-source voltage V of the transistor Tr1 gs (indicated by the dotted arrow) is such that V gp and the potential V sig are used to obtain V gs = V gp - V sig . Since the gate-source voltage V of the transistor Tr1 gs is determined, the current flowing through the transistor Tr1 is also determined. For example, in the saturation region, a current I gs proportional to the square of the voltage obtained by subtracting the threshold voltage V th of the transistor Tr1 from the voltage V S flows between the source and drain of the transistor Tr1.

[0070] The potential V gp can be set to a potential such that the transistor Tr1 is turned on regardless of the value of the potential V sig . That is, regardless of the value of the potential V sig , the value of the potential V gs can be set so that V th - V is a positive value. gp

[0071] In this way, by adopting a configuration in which the driving transistor for display and the readout transistor for imaging are combined into one transistor, not only the number of transistors in the pixel circuit but also the wiring connected to the pixel circuit can be reduced, and the pixel circuit can be simplified. Therefore, it becomes easier to increase the definition and resolution of the display device. Also, since the number of wirings is reduced, the power consumption of the display device can be decreased.

[0072] [Modification Example] Hereinafter, a configuration example of a pixel circuit with a further reduced number of elements compared to the configuration exemplified above will be described.

[0073] FIG. 4A shows a part of the pixel circuit. The pixel circuit shown in FIG. 4A includes a switch SW1, a switch SW2, a switch SW3, a transistor Tr1, a capacitor CS, and a light-emitting / receiving element SA. The pixel circuit shown in FIG. 4A is mainly different from the configuration exemplified in FIG. 1 in that it does not have a switch SW4 and does not have a wiring WX.

[0074] The wiring AL serves as a wiring that also has the function of the above-mentioned wiring WX. That is, the wiring AL is given during a period when the anode potential and the potential V RS are different. Also, the wiring AL functions as a readout wiring.

[0075] Hereinafter, the operation method of the pixel circuit shown in FIG. 4A will be described.

[0076] First, the case where the light-emitting / receiving element SA is used as a light-emitting element will be described.

[0077] During the data writing period, as shown in FIG. 4B, all of the switch SW1, the switch SW2, and the switch SW3 are turned on. As a result, the data potential V data is given to the gate of the transistor Tr1 from the wiring SL via the switch SW1.

[0078] Subsequently, during the holding and light-emitting period, as shown in FIG. 4C, the switch SW1 is turned off. As a result, a current corresponding to the gate potential of the transistor Tr1 flows through the light-emitting / receiving element SA, and the light-emitting / receiving element SA emits light with a luminance corresponding to the magnitude of the current.

[0079] Subsequently, the case where the light-emitting / receiving element SA is used as a light-receiving element will be described.

[0080] During the reset period, as shown in Fig. 5A, all of switch SW1, switch SW2, and switch SW3 are turned on. Also, to the gate of transistor Tr1, a potential V H is applied from wiring SL via switch SW1. Also, to wiring AL, a potential V RS is applied.

[0081] The potential V H is a potential that turns transistor Tr1 on. The potential V H may be, for example, a potential higher than the potential V RS or a potential higher than the potential applied to wiring CL (cathode potential).

[0082] When transistor Tr1 is turned on, to the anode of light-emitting and receiving element SA, a potential V RS is applied from wiring AL via switch SW2, transistor Tr1, and switch SW3.

[0083] After the reset period, an operation period as shown in Fig. 5B may be provided.

[0084] Specifically, in Fig. 5B, after the above reset period, switch SW3 is turned off, and potentials V H are applied to wiring SL and wiring AL, respectively. Thereby, the same potential V H is applied to the pair of electrodes of capacitor CS, and a state where no potential difference occurs is obtained. Similarly, no potential difference occurs between the source and gate of transistor Tr1. When the threshold voltage of transistor Tr1 is positive, transistor Tr1 is turned off.

[0085] In this way, by discharging capacitor CS after the reset period and keeping it in a state where no charge is accumulated, noise in the imaging data can be reduced.

[0086] Subsequently, in the exposure period shown in Fig. 5C, switch SW1, switch SW2, and switch SW3 are turned off.

[0087] Subsequently, in the transfer period shown in FIG. 5D, while keeping the switch SW2 in the non-conductive state, the switches SW1 and SW3 are made conductive respectively. As a result, to one electrode of the gate of the transistor Tr1 and the capacitor CS, the potential V is applied from the wiring SL through the switch SW1. gp Also, the potential of the other of the source and drain of the transistor Tr1 after transfer and the other electrode of the capacitor CS becomes the potential V sig as described above.

[0088] After the transfer period and until the read period, the switches SW1 and SW3 may be made non-conductive.

[0089] Finally, in the read period shown in FIG. 5E, the switch SW1 is made non-conductive and the switches SW2 and SW3 are made conductive. Here, since the capacitor CS is charged with the voltage V gs a current I corresponding to the voltage V gs flows through the transistor Tr1. By detecting this current I S with a read circuit connected to the wiring AL, the data of the pixel can be read out. S The above is the description of the modified example.

[0090] The above is the description of the modified example.

[0091] [Configuration Example 2] [Configuration Example 1 of the Display Device] Hereinafter, a more specific configuration example of the display device according to one aspect of the present invention will be described.

[0092] FIG. 6 shows a block diagram for explaining 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.

[0093] The display unit 11 has a plurality of pixels 30 arranged in a matrix. The pixel 30 has a sub-pixel 20R, a sub-pixel 20G, and a sub-pixel 20B. The sub-pixel 20R has a light-emitting and receiving element, and the sub-pixels 20G and 20B each have a light-emitting element.

[0094] Wiring SL1, wiring GL, wiring SE, wiring WX, etc. are electrically connected to the sub-pixel 20R. Wiring SL2 and wiring GL, etc. are electrically connected to the sub-pixel 20G. Wiring SL3 and wiring GL, etc. are electrically connected to the sub-pixel 20B.

[0095] Wiring SL1, wiring SL2, and wiring SL3 are each electrically connected to the drive circuit unit 12. Wiring GL is electrically connected to the drive circuit unit 13. The drive circuit unit 12 functions as a source line drive circuit (also referred to as a source driver) and supplies a data signal (data potential) to each sub-pixel via wiring SL1, wiring SL2, and wiring SL3. The drive circuit unit 13 functions as a gate line drive circuit (also referred to as a gate driver) and supplies a selection signal to wiring GL.

[0096] Wiring SE is electrically connected to the drive circuit unit 14. The drive circuit unit 14 has a function of generating a signal for supplying to the sub-pixel 20R and outputting it to wiring SE, etc. Further, the drive circuit unit 14 has a function of generating and outputting a signal for supplying to wiring AEN, wiring REN, etc. described later. Note that the drive circuit unit 13 or the drive circuit unit 12 may have a function of generating a signal for supplying to wiring AEN, wiring REN, etc.

[0097] Wiring WX is electrically connected to the circuit unit 15. The circuit unit 15 has a function of receiving a signal output from the sub-pixel 20R via wiring WX and outputting it to the outside as imaging data. The circuit unit 15 functions as a readout circuit. Further, the circuit unit 15 has a function of generating and outputting a signal for supplying to wiring WX. Therefore, the circuit unit 15 also has a function as a drive circuit. Note that the drive circuit unit 13 or the drive circuit unit 12 may have a function of generating a signal for supplying to wiring WX and outputting it.

[0098] 〔Configuration Example of Pixel〕 FIG. 7 shows an example of the circuit diagram of pixel 30. Pixel 30 has sub-pixels 20R, 20G, and 20B. Sub-pixel 20R has circuit 21R and light-emitting and receiving element SR. Sub-pixel 20G has circuit 21G and light-emitting element ELG. Sub-pixel 20B has circuit 21B and light-emitting element ELB.

[0099] Circuit 21R has transistor M1, transistor M2, transistor M4, transistor M5, transistor M6, capacitor C1, etc.

[0100] When light-emitting and receiving element SR is used as a light-emitting element, circuit 21R functions as a circuit for controlling the light emission of light-emitting and receiving element SR. Circuit 21R has a function of controlling the current flowing through light-emitting and receiving element SR according to the data potential supplied from wiring SL1.

[0101] Also, when light-emitting and receiving element SR is used as a light-receiving element, circuit 21R functions as a sensor circuit for controlling the operation of light-emitting and receiving element SR. Circuit 21R has functions of applying a reverse bias voltage to light-emitting and receiving element SR, controlling the exposure period of light-emitting and receiving element SR, holding the potential based on the charge transferred from light-emitting and receiving element SR, and outputting a signal based on the potential to wiring WX.

[0102] Sub-pixel 20R shown in FIG. 7 corresponds to the configuration exemplified in FIG. 1. Transistor M2 corresponds to transistor Tr1 in FIG. 1. Similarly, transistor M1 corresponds to switch SW1, transistor M4 corresponds to switch SW2, transistor M5 corresponds to switch SW3, and transistor M6 corresponds to switch SW4, respectively.

[0103] Transistor M1 has its gate electrically connected to wiring GL, one of its source and drain electrically connected to wiring SL1, and the other electrically connected to the gate of transistor M2 and one electrode of capacitor C1. One of the source and drain of transistor M2 is electrically connected to the other of the source and drain of transistor M4, and the other is electrically connected to one of the source and drain of transistor M5, one of the source and drain of transistor M6, and the other electrode of capacitor C1. The gate of transistor M4 is electrically connected to wiring AEN, and one of its source and drain is electrically connected to wiring AL. The gate of transistor M5 is electrically connected to wiring REN, and the other of its source and drain is electrically connected to the anode of light-emitting and receiving element SR. The gate of transistor M6 is electrically connected to wiring SE, and the other of its source and drain is electrically connected to wiring WX. The cathode of light-emitting and receiving element SR is electrically connected to wiring CL.

[0104] To wiring SL1, data potentials V data , potential V off , potential V gp etc. are applied in different periods. An anode potential is applied to wiring AL. A cathode potential is applied to wiring CL. In the configuration shown in FIG. 7, the anode potential is set to a potential higher than the cathode potential. To wiring WX, potential V0, potential V RS etc. are applied in different periods. Also, wiring WX has a function as a readout line. To wiring AEN, wiring REN, wiring GL, and wiring SE, signals for controlling the conduction and non-conduction of transistor M4, transistor M5, transistor M1, and transistor M6 are respectively applied.

[0105] Transistor M6 functions as a selection transistor for reading. The conduction and non-conduction of transistor M6 are controlled by the signal applied to wiring SE. By setting transistor M6 and transistor M4 in the conduction state, transistor M2 and wiring WX are made conductive, and a current (or voltage) corresponding to the gate-source voltage V gs of transistor M2 can be output to wiring WX.

[0106] The sub-pixel 20G includes a circuit 21G and a light-emitting element ELG. The sub-pixel 20B includes a circuit 21B and a light-emitting element ELB. The circuit 21G and the circuit 21B have the same configuration.

[0107] The circuit 21G and the circuit 21B include a transistor M1, a transistor M2, a transistor M3, and a capacitor C1. The gate of the transistor M3 is electrically connected to the wiring GL, and one of the source and the drain is electrically connected to the other electrode of the capacitor C1, the other of the source and the drain of the transistor M2, and the anode of the light-emitting element ELG or the light-emitting element ELB, and the other is electrically connected to the wiring V0L.

[0108] A fixed potential is applied to the wiring V0L. For example, the same potential as the potential V0 applied to the wiring WX may be applied to the wiring V0L. Alternatively, the wiring WX may be used instead of the wiring V0L.

[0109] Here, when comparing the number of transistors between the circuit 21R and the circuit 21G or the circuit 21B, the difference is only two. Thus, in one aspect of the present invention, a circuit that can function as both a light-emitting element and a light-receiving element can be configured by adding only two transistors to the circuit that drives the light-emitting element. Therefore, an increase in the occupied area of the circuit 21R can be suppressed, and a display device with a high pixel density can be realized.

[0110] For the transistors M1, M3, M4, M5, and M6 that function as switches, it is preferable to apply transistors with an extremely small leakage current in the non-conductive state. In particular, transistors using an oxide semiconductor for the semiconductor layer where the channel is formed can be preferably used. Also, by applying a transistor using an oxide semiconductor to transistor M2 as well, all the transistors can be formed through a common manufacturing process, which is preferable. Note that for transistor M2, silicon (including amorphous silicon, polycrystalline silicon, and single-crystalline silicon) may be applied to the semiconductor layer where the channel is formed. Note that this is not limited thereto, and transistors using silicon can also be used for some or all of the transistors. Also, for some or all of the transistors, transistors using an inorganic semiconductor, a compound semiconductor, an organic semiconductor, or the like other than silicon may be used.

[0111] Also, as shown in FIG. 8A, each transistor may be configured to apply a transistor having a back gate. FIG. 8A shows a configuration in which a pair of gates are electrically connected.

[0112] Note that in FIG. 8A, all the transistors are configured such that a pair of gates are electrically connected, but this is not limited thereto. Pixel 30 may have a transistor that connects one of the gates to another wiring. For example, by connecting one of the pair of gates to a wiring to which a fixed potential is applied, the stability of the electrical characteristics can be improved. Also, 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. Also, as shown in FIG. 8B, for one of the pair of gates, a transistor in which one of the gates is connected to one of the source and the drain may be used. At this time, it is preferable to connect one of the gates to the source. For example, the transistors shown in FIG. 8B can be preferably used for transistors M2 and M4 in pixel 30.

[0113] Also, although an example in which all 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.

[0114] 〔Modification Example〕 Hereinafter, a configuration example of a pixel having a configuration partially different from the above will be described.

[0115] FIG. 9 shows a circuit diagram of a pixel 30A exemplified below. The configuration example exemplified in FIG. 9 has a different configuration of circuit 21R, circuit 21G, and circuit 21B compared to FIG. 7.

[0116] In circuit 21R, transistor M6, wiring WX, and wiring SE are omitted from circuit 21R exemplified in FIG. 7. Circuit 21R corresponds to the configuration exemplified in FIG. 4A above.

[0117] Also, in circuit 21G, transistor M3 and wiring V0L are omitted from circuit 21G exemplified in FIG. 7. Note that the same applies to circuit 21B.

[0118] With such a configuration, the number of transistors and wirings can be further reduced. Specifically, compared to the configuration exemplified in FIG. 7, three transistors and four wirings are reduced. With such a configuration, further high definition and high aperture ratio can be achieved.

[0119] The above is the description of the modification example.

[0120] 〔Configuration Example 2 of Display Device〕 In the above, an example in which one pixel has three sub-pixels has been shown. Hereinafter, an example in which one pixel has two sub-pixels will be described.

[0121] FIG. 10A shows an example of an arrangement method for 3×3 pixels. In FIG. 10A, pixels from the i-th row and j-th column (i and j are each independently an integer of 1 or more) to the (i + 2)-th row and (j + 2)-th column are shown.

[0122] In FIG. 10A, pixel 30G and pixel 30B are alternately arranged in the row direction and the column direction. Pixel 30G has sub-pixels 20R and 20G. Pixel 30B has sub-pixels 20R and 20B.

[0123] For example, for pixel 30G located at the i-th row and j-th column, wiring GL[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 are connected thereto.

[0124] FIG. 10B shows an example of the arrangement method of light emitting and receiving element SR, light emitting element ELG, and light emitting element ELB. Light emitting and receiving element SR is arranged at equal intervals in the row direction and the column direction. Also, light emitting element ELG and light emitting element ELB are alternately arranged in the row direction and the column direction, respectively. Further, the shapes of light emitting and receiving element SR, light emitting element ELG, and light emitting element ELB are each a shape in which a square is inclined by about 45 degrees with respect to the arrangement direction. Thereby, the distance between adjacent elements can be increased, and when manufacturing the light emitting element and the light emitting and receiving element separately, they can be manufactured with good yield.

[0125] [Example of driving method] Hereinafter, an example of a driving method of the display device will be described.

[0126] Here, a configuration having three sub-pixels in one pixel, which is exemplified in FIG. 6, will be described as an example. A more specific configuration is shown in FIG. 11. FIG. 11 shows circuit diagrams of two adjacent pixels 30 in the column direction. Here, circuit diagrams of pixels 30 for two rows, namely the i-th row and j-th column and the (i + 1)-th row and j-th column, are shown.

[0127] Hereinafter, as the display device, a display device having a configuration in which a plurality of pixels are arranged in a matrix in M rows and N columns (M and N are each independently an integer of 2 or more) in the display unit will be used.

[0128] Figures 12 and 13 schematically show the operation of the display device. The operation of the display device is roughly divided into a period (display period) in which an image is displayed using a light-emitting element and a light-receiving and emitting element, and a period (imaging period) in which imaging is performed using a light-receiving and emitting element (also referred to as a sensor). The display period is a period in which image data is written to a pixel and display based on the image data is performed. The imaging period is a period in which imaging by the light-receiving and emitting element and reading of imaging data are performed.

[0129] First, using FIG. 12, the operation during the display period will be described.

[0130] During the display period, the operation of writing data to the pixel is repeatedly performed. During that period, it is assumed that the operation of the sensor is not performed (referred to as blank). Note that imaging operation can also be performed during the display period.

[0131] In one write operation, image data for one frame is written. As shown in FIG. 12, in one write operation (referred to as write), data is sequentially written to the pixels from the first column to the M-th column.

[0132] FIG. 12 shows a timing chart of the write operations for the data of the i-th row and the (i + 1)-th row. Here, the potential transitions of the wirings GL[i], GL[i + 1], SE[i], SE[i + 1], AEN, REN, WX, SL1[j], SL2[j], and SL3[j] are shown. Regarding the connection relationship between each wiring and each pixel, FIGS. 6 and 11 can be referred to.

[0133] During the write period of the i-th row, high-level potentials are applied to the wirings GL[i], SE[i], AEN, and REN. Also, a potential V0 is applied to the wiring WX. Also, the data potential D R [i,j] is applied to the wiring SL2[j], and the data potential D G [i,j] is applied to the wiring SL3[j], and the data potential D B [i,j] are respectively applied.

[0134] For the writing from the (i + 1)-th row and below, similar to the above, by applying a high-level potential to the corresponding wiring GL and wiring SE and applying data potentials to wiring SL1, wiring SL2, and wiring SL3 respectively, writing can be performed line by line.

[0135] By performing such a writing operation from the first row to the M-th row, the data writing of one frame is completed. During the display period, by repeatedly executing the above operation, a video can be displayed.

[0136] Subsequently, with reference to FIG. 13, the operation during the imaging period will be described. Here, the case of performing the imaging operation in the global shutter method will be described. Note that the method is not limited to the global shutter method, and the driving method of the rolling shutter method can also be applied.

[0137] The imaging period is divided into a period of performing imaging simultaneously at each pixel (referred to as imaging. Hereinafter, in order to distinguish it from the imaging period, it is also called the imaging operation period) and a period of sequentially reading out the imaging data (referred to as readout). The imaging operation period is divided into an initialization period, an exposure period, and a transfer period. Also, during the readout period, the imaging data is read out line by line from the first row to the M-th row.

[0138] FIG. 13 shows the timing charts during the imaging operation period and the readout period. Here, the potential transitions of wiring GL[1:M], wiring SE[i], wiring SE[i + 1], wiring AEN, wiring REN, wiring SL1[1:N], wiring SL2[1:N], wiring SL3[1:N], and wiring WX[1:N] are shown. Here, the wiring GL is collectively denoted as wiring GL[1:M], and the wiring WX is collectively denoted as wiring WX[1:N]. Similarly, wiring SL1, wiring SL2, and wiring SL3 are also collectively denoted.

[0139] During the initialization period, a low-level potential is applied to wiring AEN. As a result, in all sub-pixels 20R, transistor M4 becomes non-conductive. This can electrically insulate the light-emitting and receiving element SR from wiring AL and prevent the light-emitting and receiving element SR from emitting light unintentionally.

[0140] Also, a high-level potential is applied to all wiring GL, all wiring SE, and wiring REN. As a result, transistors M1, M5, and M6 in the sub-pixel 20R become conductive. Then, potential V is applied to all wiring SL1, and potential V is applied to all wiring WX. This causes a reset operation to be performed in all sub-pixels 20R. off to all wiring SL1, and potential V is applied to all wiring WX. This causes a reset operation to be performed in all sub-pixels 20R. RS to all wiring SL1, and potential V is applied to all wiring WX. This causes a reset operation to be performed in all sub-pixels 20R.

[0141] Here, data potential D or data potential D may be applied to wiring SL2 and wiring SL3. This can cause one or both of the light-emitting elements ELG and ELB to emit light and be used as a light source during imaging. G or data potential D may be applied to wiring SL2 and wiring SL3. This can cause one or both of the light-emitting elements ELG and ELB to emit light and be used as a light source during imaging. B or data potential D may be applied to wiring SL2 and wiring SL3. This can cause one or both of the light-emitting elements ELG and ELB to emit light and be used as a light source during imaging.

[0142] Subsequently, during the exposure period, a low-level potential is applied to wiring GL, wiring SE, and wiring REN. As a result, charges corresponding to the amount of light irradiated are accumulated in the light-emitting and receiving element SR.

[0143] Subsequently, during the transfer period, a high-level potential is applied to wiring GL and wiring REN. As a result, transistors M1 and M5 in the sub-pixel 20R become conductive. At this time, the charges accumulated in the light-emitting and receiving element SR can be transferred to the node to which the source of transistor M2 is connected. Furthermore, potential V is applied from wiring SL1 to the node to which the gate of transistor M2 is connected via transistor M1. Then, by applying a low-level potential to wiring GL and wiring REN, the potentials of the above two nodes are maintained. gp Subsequently, during the transfer period, a high-level potential is applied to wiring GL and wiring REN. As a result, transistors M1 and M5 in the sub-pixel 20R become conductive. At this time, the charges accumulated in the light-emitting and receiving element SR can be transferred to the node to which the source of transistor M2 is connected. Furthermore, potential V is applied from wiring SL1 to the node to which the gate of transistor M2 is connected via transistor M1. Then, by applying a low-level potential to wiring GL and wiring REN, the potentials of the above two nodes are maintained.

[0144] Subsequently, the imaging data is read out row by row. During the read period, a high-level potential is applied to the wiring AEN. Further, during the read period, by sequentially applying a high-level potential from the wiring SE[1] to the wiring SE[N], data can be read out for all pixels. For example, in the read of the i-th row, by applying a high-level potential to the wiring SE[i], the data D W [i] of the i-th row is output to the wiring WX[1:N]. Specifically, for one wiring WX[j], the data D W [i,j] of the i-th row and j-th column is output.

[0145] Here, during the exposure period and the read 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 potential V gp is held applied to the gate of the transistor M2. Therefore, imaging with reduced noise can be executed. Since the transistor M1 is in a non-conducting state at this time, the potential applied to the wiring SL1 does not matter (denoted as don‘t care). Similarly, the potentials applied to the wiring SL2 and the wiring SL3 do not matter.

[0146] Note that here, an example where one data is output in the read of one row is shown, but two data may be output, and correlated double sampling (CDS) may be performed using these two output data. By performing CDS, the influence of variations in the electrical characteristics of each pixel can be reduced.

[0147] For example, during the read period of one row, by applying a high-level potential to the wiring GL and applying a predetermined potential from the wiring SL1, the second data can be output to the wiring WX.

[0148] The above is the description of the example of the driving method.

[0149] The configuration examples illustrated in this embodiment, and the corresponding drawings and the like can be appropriately combined with at least a part of other configuration examples, or drawings and the like.

[0150] This embodiment can be implemented by appropriately combining at least a part of it with other embodiments described in this specification.

[0151] (Embodiment 2) In this embodiment, a display device according to an aspect of the present invention will be described.

[0152] A display device according to an aspect of the present invention has a light-emitting element and a light-emitting and receiving element.

[0153] The light-emitting and receiving element can be manufactured by combining an organic EL element, which is a light-emitting element, and an organic photodiode, which is a light-receiving element. For example, a light-emitting and receiving element can be manufactured by adding an active layer of an organic photodiode to the stacked structure of the organic EL element. Furthermore, in the light-emitting and receiving element manufactured by combining an organic EL element and an organic photodiode, the layers that can be made into a common configuration with the light-emitting element can be formed in a batch, thereby suppressing an increase in the film-forming process.

[0154] For example, one of the pair of electrodes (common electrode) can be a common layer for the light-emitting and receiving element and the light-emitting element. Also, for example, it is preferable that at least one of the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer is a common layer for the light-emitting and receiving element and the light-emitting element. Also, for example, except for the presence or absence of the active layer of the light-receiving element, the light-emitting and receiving element and the light-emitting element can have the same configuration. That is, a light-emitting and receiving element can also be manufactured by simply adding the active layer of the light-receiving element to the light-emitting element. In this way, since the light-emitting and receiving element and the light-emitting element have a common layer, the number of film-forming times and the number of masks can be reduced, and the manufacturing process and manufacturing cost of the display device can be reduced. Also, a display device having a light-emitting and receiving element can be manufactured using the existing manufacturing equipment and manufacturing method of the display device.

[0155] Note that the layers of the light-emitting and light-receiving element may have different functions depending on whether the light-emitting and light-receiving element functions as a light-receiving element or as a light-emitting element. In this specification, components are named based on the functions when the light-emitting and light-receiving element functions as a light-emitting element. For example, the hole injection layer functions as a hole injection layer when the light-emitting and light-receiving element functions as a light-emitting element, and functions as a hole transport layer when the light-emitting and light-receiving element functions as a light-receiving element. Similarly, the electron injection layer functions as an electron injection layer when the light-emitting and light-receiving element functions as a light-emitting element, and functions as an electron transport layer when the light-emitting and light-receiving element functions as a light-receiving element.

[0156] As described above, the display device of this embodiment has a light-emitting and light-receiving element and a light-emitting element in the display unit. Specifically, in the display unit, the light-emitting and light-receiving elements and the light-emitting elements are each arranged in a matrix. Therefore, in addition to the function of displaying an image, the display unit also has one or both of an imaging function and a sensing function.

[0157] The display unit can be used for an image sensor, a touch sensor, etc. That is, by detecting light with the display unit, it is possible to capture an image, detect the approach or contact of an object (finger, pen, etc.). Further, the display device of this embodiment can use the light-emitting element as a light source of 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 parts of the electronic device can be reduced.

[0158] In the display device of this embodiment, when the light emitted from the light-emitting element of the display unit is reflected by an object, the light-emitting and light-receiving element can detect the reflected light. Therefore, imaging, touch (contact or approach) detection, etc. are possible even in a dark place.

[0159] The display device of this embodiment has a function of displaying an image using the light-emitting element and the light-emitting and light-receiving element. That is, the light-emitting element and the light-emitting and light-receiving element function as display elements.

[0160] 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 the light-emitting substance included in the EL element include a substance that emits fluorescence (fluorescent material), a substance that emits phosphorescence (phosphorescent material), an inorganic compound (such as a quantum dot material), and a substance that exhibits thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) material). Further, an LED such as a micro LED (Light Emitting Diode) can also be used as the light-emitting element.

[0161] The display device according to the present embodiment has a function of detecting light by using a light-emitting and receiving element. The light-emitting and receiving element can detect light having a shorter wavelength than the light emitted by the light-emitting and receiving element itself.

[0162] When the light-emitting and receiving element is used as an image sensor, the display device according to the present embodiment can capture an image by using the light-emitting and receiving element. For example, the display device according to the present embodiment can be used as a scanner.

[0163] For example, data such as fingerprints and palm prints can be acquired by using an image sensor. That is, a biometric authentication sensor can be incorporated in the display device according to the present embodiment. By incorporating the biometric authentication sensor in the display device, the number of components of the electronic device can be reduced compared to the case where a biometric authentication sensor is provided separately from the display device, and the electronic device can be miniaturized and lightened.

[0164] In addition, by using an image sensor, it is possible to acquire data such as a user's facial expression, eye movement, or change in pupil diameter. By analyzing the data, it is possible to obtain information about the user's physical and mental state. Based on this information, by changing the output content of one or both of the display and audio, for example, in a device for VR (Virtual Reality), AR (Augmented Reality), or MR (Mixed Reality), it is possible to ensure that the user can safely use the device.

[0165] In addition, when the light-emitting and light-receiving element is used as a touch sensor, the display device of the present embodiment can detect the approach or contact of an object by using the light-emitting and light-receiving element.

[0166] The light-emitting and light-receiving element functions as a photoelectric conversion element that detects light incident on the light-emitting and light-receiving element and generates electric charges. The amount of generated electric charges is determined based on the amount of incident light.

[0167] The light-emitting and light-receiving element can be manufactured by adding the active layer of the light-receiving element to the configuration of the above-described light-emitting element.

[0168] For the light-emitting and light-receiving element, for example, the active layer of a pn-type or pin-type photodiode can be used.

[0169] In particular, it is preferable to use the active layer of an organic photodiode having a layer containing an organic compound for the light-emitting and light-receiving element. Since organic photodiodes are easy to thin, lighten, and increase in area, and also have a high degree of freedom in shape and design, they can be applied to various display devices.

[0170] Cross-sectional views of a display device according to an aspect of the present invention are shown in FIGS. 14A to 14D.

[0171] The display device 350A shown in FIG. 14A has a layer 353 having a light-emitting and light-receiving element and a layer 357 having a light-emitting element between a substrate 351 and a substrate 359.

[0172] The display device 350B shown in Fig. 14B has a layer 353 having light-emitting and light-receiving elements, a layer 355 having transistors, and a layer 357 having light-emitting elements between a substrate 351 and a substrate 359.

[0173] The display devices 350A and 350B are configured such that green (G) light and blue (B) light are emitted from the layer 357 having light-emitting elements, and red (R) light is emitted from the layer 353 having light-emitting and light-receiving elements. Note that in the display device according to one aspect of the present invention, the color of the light emitted from the layer 353 having light-emitting and light-receiving elements is not limited to red.

[0174] The light-emitting and light-receiving elements included in the layer 353 having light-emitting and light-receiving elements can detect light incident from outside the display device 350A or the display device 350B. The light-emitting and light-receiving elements can detect, for example, one or both of green (G) light and blue (B) light.

[0175] The display device according to one aspect of the present invention has a plurality of pixels arranged in a matrix. One pixel has one or more sub-pixels. One sub-pixel has one light-emitting and light-receiving element or one light-emitting element. For example, a configuration in which a pixel has three sub-pixels (three colors of R, G, and B, or three colors of yellow (Y), cyan (C), and magenta (M), etc.) or a configuration in which a pixel has four sub-pixels (four colors of R, G, B, and white (W), or four colors of R, G, B, and Y, etc.) can be applied. At least one color sub-pixel has a light-emitting and light-receiving element. The light-emitting and light-receiving elements may be provided in all pixels or in some pixels. Also, one pixel may have a plurality of light-emitting and light-receiving elements.

[0176] The layer 355 having transistors has, for example, transistors electrically connected to light-emitting and light-receiving elements and transistors electrically connected to light-emitting elements. The layer 355 having transistors may further have wiring, electrodes, terminals, capacitors, resistors, and the like.

[0177] A display device according to an aspect of the present invention may have a function of detecting an object such as a finger in contact with the display device (FIG. 14C). Alternatively, it may have a function of detecting an object approaching (not in contact with) the display device (FIG. 14D). For example, as shown in FIGS. 14C and 14D, light emitted by a light-emitting element in a layer 357 having a light-emitting element is reflected by a finger 352 in contact with or approaching the display device 350B, and a light-receiving and emitting element in a layer 353 having a light-receiving and emitting element detects the reflected light. Thereby, it can be detected that the finger 352 has come into contact with or approached the display device 350B.

[0178] [Pixel] Examples of pixels are shown in FIGS. 14E to 14G and FIGS. 15A to 15D. Note that the arrangement order of the sub-pixels is not limited to the illustrated order. For example, the positions of the sub-pixel 311B and the sub-pixel 311G may be reversed.

[0179] The pixel shown in FIG. 14E has a stripe arrangement applied. The pixel has a sub-pixel 311SR that exhibits red light and has a light-receiving function, a sub-pixel 311G that exhibits green light, and a sub-pixel 311B that exhibits blue light. In a display device in which a pixel is composed of three sub-pixels of R, G, and B, by replacing the light-emitting element used for the R sub-pixel with a light-receiving and emitting element, a display device having a light-receiving function can be manufactured for the pixel.

[0180] The pixel shown in FIG. 14F has a matrix arrangement applied. The pixel has a sub-pixel 311SR that exhibits red light and has a light-receiving function, a sub-pixel 311G that exhibits green light, a sub-pixel 311B that exhibits blue light, and a sub-pixel 311W that exhibits white light. Even in a display device in which a pixel is composed of four sub-pixels of R, G, B, and W, by replacing the light-emitting element used for the R sub-pixel with a light-receiving and emitting element, a display device having a light-receiving function can be manufactured for the pixel.

[0181] The pixels shown in FIG. 14G have a pentile arrangement. In FIG. 14G, the pixels have sub-pixels that exhibit two different colors of light in combination. The upper left pixel and the lower right pixel shown in FIG. 14G exhibit red light and have a sub-pixel 311SR that has a light-receiving function and a sub-pixel 311G that exhibits green light. The lower left pixel and the upper right pixel shown in FIG. 14G have a sub-pixel 311G that exhibits green light and a sub-pixel 311B that exhibits blue light. Note that the shape of the sub-pixels shown in FIG. 14G indicates the upper surface shape of the light-emitting element or the light-emitting and light-receiving element that the sub-pixel has.

[0182] The pixels shown in FIG. 15A have a sub-pixel 311SR that exhibits red light and has a light-receiving function, a sub-pixel 311G that exhibits green light, and a sub-pixel 311B that exhibits blue light. The sub-pixel 311SR is arranged in a column different from the sub-pixels 311G and 311B. The sub-pixels 311G and 311B are alternately arranged in the same column, with one provided in odd rows and the other provided in even rows. Note that the sub-pixel arranged in a column different from the sub-pixels of other colors is not limited to red (R), and may be green (G) or blue (B).

[0183] FIG. 15B shows two pixels, and one pixel is composed of three sub-pixels surrounded by a dotted line. The pixels shown in FIG. 15B have a sub-pixel 311SR that exhibits red light and has a light-receiving function, a sub-pixel 311G that exhibits green light, and a sub-pixel 311B that exhibits blue light. In the left pixel shown in FIG. 15B, the sub-pixel 311G is arranged in the same row as the sub-pixel 311SR, and the sub-pixel 311B is arranged in the same column as the sub-pixel 311SR. In the right pixel shown in FIG. 15B, the sub-pixel 311G is arranged in the same row as the sub-pixel 311SR, and the sub-pixel 311B is arranged in the same column as the sub-pixel 311G. In the pixel layout shown in FIG. 15B, in both odd rows and even rows, the sub-pixels 311SR, 311G, and 311B are repeatedly arranged, and in each column, sub-pixels of different colors are arranged in odd rows and even rows.

[0184] FIG. 15C is a modified example of the pixel array shown in FIG. 14G. The upper left pixel and the lower right pixel shown in FIG. 15C exhibit red light and have sub-pixels 311SR that exhibit red light and have a light receiving function, and sub-pixels 311G that exhibit green light. The lower left pixel and the upper right pixel shown in FIG. 15C exhibit red light and have sub-pixels 311SR that exhibit red light and have a light receiving function, and sub-pixels 311B that exhibit blue light.

[0185] In FIG. 14G, sub-pixels 311G that exhibit green light are provided for each pixel. On the other hand, in FIG. 15C, sub-pixels 311SR that exhibit red light and have a light receiving function are provided for each pixel. Since sub-pixels having a light receiving function are provided for each pixel, in the configuration shown in FIG. 15C, imaging can be performed with higher resolution than the configuration shown in FIG. 14G. Thereby, for example, the accuracy of biometric authentication can be improved.

[0186] Further, the upper surface shape of the light emitting element and the light emitting and receiving element is not particularly limited, and can be a circle, an ellipse, a polygon, a rounded polygon, or the like. Regarding the upper surface shape of the light emitting element included in the sub-pixel 311G, an example of a circular shape is shown in FIG. 14G, and an example of a square shape is shown in FIG. 15C. The upper surface shapes of the light emitting elements and the light emitting and receiving elements of each color may be different from each other, or may be the same for some or all colors.

[0187] Also, the aperture ratios of the sub-pixels of each color may be different from each other, or may be the same for some or all colors. For example, the aperture ratio of the sub-pixel provided for each pixel (sub-pixel 311G in FIG. 14G, sub-pixel 311SR in FIG. 15C) may be made smaller than the aperture ratios of the sub-pixels of other colors.

[0188] FIG. 15D is a modified example of the pixel array shown in FIG. 15C. Specifically, the configuration of FIG. 15D is obtained by rotating the configuration of FIG. 15C by 45°. In FIG. 15C, it has been described that one pixel is constituted by two sub-pixels, but as shown in FIG. 15D, it can also be considered that one pixel is constituted by four sub-pixels.

[0189] In FIG. 15D, the description will be given assuming that one pixel is composed of four sub-pixels surrounded by a dotted line. One pixel has two sub-pixels 311SR, one sub-pixel 311G, and one sub-pixel 311B. In this way, by having a plurality of sub-pixels having a light receiving function in one pixel, imaging can be performed with high definition. Therefore, the accuracy of biometric authentication can be improved. For example, the imaging definition can be set to √2 times the display definition.

[0190] The display device to which the configuration shown in FIG. 15C or FIG. 15D is applied has p first light emitting elements (p is an integer of 2 or more), q second light emitting elements (q is an integer of 2 or more), and r light emitting and receiving elements (r is an integer larger than p and larger than q). p and r satisfy r = 2p. Also, p, q, and r satisfy r = p + q. One of the first light emitting element and the second light emitting element emits green light, and the other emits blue light. The light emitting and receiving element emits red light and has a light receiving function.

[0191] For example, when performing touch detection using the light emitting and receiving element, it is preferable that the light emission from the light source is difficult for the user to visually recognize. Since blue light has lower visibility than green light, it is preferable to use a light emitting element that emits blue light as the light source. Therefore, it is preferable that the light emitting and receiving element has a function of receiving blue light and converting it into an electrical signal.

[0192] As described above, various pixel arrays can be applied to the display device according to one aspect of the present invention.

[0193] In the display device of the present embodiment, since it is not necessary to change the pixel array in order to incorporate the light receiving function into the pixel, it is possible to add one or both of the imaging function and the sensing function to the display unit without reducing the aperture ratio and the definition.

[0194] [Light emitting and receiving element] Examples of the stacked structure of the light emitting and receiving element are shown in FIGS. 16A to 16E.

[0195] The light-emitting and light-receiving element has at least an active layer and a light-emitting layer between a pair of electrodes.

[0196] As layers other than the active layer and the light-emitting layer, the light-emitting and light-receiving element may further have a layer containing a substance with high hole injection property, a substance with high hole transport property, a substance with high hole blocking property, a substance with high electron transport property, a substance with high electron injection property, a substance with high electron blocking property, or a bipolar substance (a substance with high electron transport property and high hole transport property), etc.

[0197] The light-emitting and light-receiving elements shown in FIGS. 16A to 16C 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.

[0198] Note that the light-emitting and light-receiving elements shown in FIGS. 16A to 16C can each be said to have a configuration in which an active layer 183 is added to the light-emitting element. Therefore, by only adding a step of forming the active layer 183 to the manufacturing process of the light-emitting element, the light-emitting and light-receiving element can be formed in parallel with the formation of the light-emitting element. Also, the light-emitting element and the light-emitting and light-receiving element can be formed on the same substrate. Therefore, one or both of the imaging function and the sensing function can be imparted to the display unit without significantly increasing the manufacturing process.

[0199] The lamination order of the light-emitting layer 193 and the active layer 183 is not limited. FIG. 16A 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. Also, FIG. 16B 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. Also, as shown in FIGS. 16A and 16B, the active layer 183 and the light-emitting layer 193 may be in contact with each other.

[0200] As shown in Fig. 16C, it is preferable that a buffer layer is sandwiched between the active layer 183 and the light-emitting layer 193. As the buffer layer, at least one layer among a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a hole blocking layer, an electron blocking layer, etc. can be used. Fig. 16C shows an example in which a hole transport layer 182 is used as the buffer layer.

[0201] By providing a buffer layer between the active layer 183 and the light-emitting layer 193, the transfer of excitation energy from the light-emitting layer 193 to the active layer 183 can be suppressed. Also, the optical path length (cavity length) of the microcavity structure can be adjusted using the buffer layer. Therefore, high luminous efficiency can be obtained from the light-emitting and receiving element having a buffer layer between the active layer 183 and the light-emitting layer 193.

[0202] The light-emitting and receiving element shown in Fig. 16D is different from the light-emitting and receiving elements shown in Figs. 16A and 16C in that it does not have a hole transport layer 182. The light-emitting and receiving element may not have at least one layer among a hole injection layer 181, a hole transport layer 182, an electron transport layer 184, and an electron injection layer 185. Also, the light-emitting and receiving element may have other functional layers such as a hole blocking layer and an electron blocking layer.

[0203] The light-emitting and receiving element shown in Fig. 16E is different from the light-emitting and receiving elements shown in Figs. 16A to 16C in that it does not have an active layer 183 and a light-emitting layer 193, but has a layer 186 that serves as both a light-emitting layer and an active layer.

[0204] As the layer 186 that serves as both a light-emitting layer and an active layer, for example, a layer containing three materials, namely 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, can be used.

[0205] Note that it is preferable that the absorption band on the lowest energy side of the absorption spectrum of the mixed material of the n-type semiconductor and the p-type semiconductor does not overlap with the maximum peak of the emission spectrum (PL spectrum) of the light-emitting substance, and it is more preferable that they are sufficiently separated.

[0206] In a light-emitting and light-receiving element, a conductive film that transmits visible light is used for the electrode on the side where light is extracted. Further, it is preferable to use a conductive film that reflects visible light for the electrode on the side where light is not extracted.

[0207] When driving the light-emitting and light-receiving element 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 a material with high hole injection properties, a composite material containing a hole transport material and an acceptor material (electron-accepting material), or an aromatic amine compound (a compound having an aromatic amine skeleton) can be used.

[0208] When driving the light-emitting and light-receiving element 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 driving the light-emitting and light-receiving element as a light-receiving element, the hole transport layer is a layer that transports holes generated based on light incident on the active layer to the anode. The hole transport layer is a layer containing a hole transport material. As the hole transport material, a substance having a hole mobility of 1×10 -6 cm 2 / Vs or more is preferable. In addition, as long as the substance has higher hole transportability than electrons, other substances can also be used. As the hole transport material, a hole transport material with high hole transportability such as a π-electron-excessive heteroaromatic compound (for example, a carbazole derivative, a thiophene derivative, a furan derivative, etc.) or an aromatic amine compound is preferable.

[0209] When driving the light-emitting and light-receiving element 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 driving the light-emitting and light-receiving element as a light-receiving element, the electron transport layer is a layer that transports electrons generated based on light incident on the active layer to the cathode. The electron transport layer is a layer containing an electron transport material. As the electron transport material, a substance having a hole mobility of 1×10 -6 cm 2A substance having an electron mobility of 1 / Vs or higher is preferred. In addition, any other substance can be used as long as it has higher electron transportability than holes. As the electron transport material, in addition to metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, etc., 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 other highly electron-transporting materials such as π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds can be used.

[0210] When driving the light-emitting device using the light-emitting element as a light-emitting element, the electron injection layer is a layer that injects electrons from the cathode into the electron transport layer. The electron injection layer is a layer containing a material with high electron injection property. As the material with high electron injection property, an alkali metal, an alkaline earth metal, or a compound thereof can be used. As the material with high electron injection property, a composite material containing an electron transport material and a donor material (electron-donating material) can also be used.

[0211] The light-emitting layer 193 is a layer containing a light-emitting substance. The light-emitting layer 193 can have one or more kinds of light-emitting substances. As the light-emitting substance, substances exhibiting light-emitting colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red can be appropriately used. In addition, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0212] Examples of the light-emitting substance include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0213] Examples of the fluorescent material 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, naphthalene derivatives, and the like.

[0214] Examples of the phosphorescent material include organometallic complexes (especially 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 (especially iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand, platinum complexes, rare-earth metal complexes, and the like.

[0215] In addition to the light-emitting substance (guest material), the light-emitting layer 193 may contain one or more organic compounds (host materials, assist materials, etc.). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material can be used. Further, a bipolar material or a TADF material may be used as the one or more organic compounds.

[0216] Preferably, the light-emitting layer 193 contains, for example, a phosphorescent material, a hole-transporting material, and an electron-transporting material which are a combination likely to form an exciplex. With such a configuration, light emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the exciplex to the light-emitting substance (phosphorescent material), can be efficiently obtained. By selecting a combination that forms an exciplex that emits light overlapping the wavelength of the absorption band on the lowest energy side of the light-emitting substance, energy transfer becomes smooth and light emission can be efficiently obtained. With this configuration, high efficiency, low-voltage driving, and long life of the light-emitting element can be realized simultaneously.

[0217] As a combination of materials for forming 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) measurement.

[0218] The formation of the exciplex can be confirmed, for example, by comparing the emission spectrum of the hole transporting material, the emission spectrum of the electron transporting material, and the emission spectrum of a mixed film in which these materials are mixed, and observing the phenomenon that the emission spectrum of the mixed film is shifted to a longer wavelength (or has a new peak on the longer wavelength side) than the emission spectra of the respective materials. Alternatively, the transient photoluminescence (PL) of the hole transporting material, the transient PL of the electron transporting material, and the transient PL of a mixed film in which these materials are mixed are compared, and the difference in transient response such that the transient PL lifetime of the mixed film has a longer lifetime component or the ratio of the delayed component becomes larger than the transient PL lifetimes of the respective materials is observed to confirm. Also, the above-mentioned transient PL may be read as transient electroluminescence (EL). That is, the transient EL of the hole transporting material, the transient EL of the material having electron transporting properties, and the transient EL of a mixed film thereof are compared, and the formation of the exciplex can also be confirmed by observing the difference in transient response.

[0219] The active layer 183 contains a semiconductor. Examples of the semiconductor include inorganic semiconductors such as silicon and organic semiconductors containing organic compounds. In the present 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 evaporation method), and it is preferable because the manufacturing apparatus can be shared.

[0220] Examples of the material of the n-type semiconductor included in the active layer 183 include fullerenes (for example, C 60 , C 70Examples of the electron-accepting organic semiconductor materials include fullerene derivatives and the like. Fullerene has a soccer ball-like shape, which is energetically stable. For fullerene, both the HOMO level and the LUMO level are deep (low). Since the LUMO level of fullerene is deep, its electron-accepting (acceptor) property is extremely high. Usually, when π-electron conjugation (resonance) spreads in a plane like benzene, the electron-donating (donor) property increases. However, for fullerene, despite the large spread of π-electrons due to its spherical shape, its electron-accepting property is high. A high electron-accepting property is beneficial for a light-receiving element because it causes efficient charge separation at high speed. C 60 , C 70 both have a broad absorption band in the visible light region. In particular, C 70 is preferable because it has a larger π-electron conjugation system than C 60 and also has a broad absorption band in the long wavelength region.

[0221] Examples of the materials for the n-type semiconductor also 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, quinone derivatives, and the like.

[0222] Examples of the materials for the p-type semiconductor included in 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.

[0223] Examples of the p-type semiconductor material include carbazole derivatives, thiophene derivatives, furan derivatives, aromatic amine compounds, etc. Further examples of the p-type semiconductor material 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, polyphenylene vinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, polythiophene derivatives, etc.

[0224] 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. 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.

[0225] As the electron-accepting organic semiconductor material, it is preferable to use spherical fullerene, and as the electron-donating organic semiconductor material, it is preferable to use an organic semiconductor material having a shape close to a plane. Molecules with similar shapes tend to aggregate easily. When the same type of molecules aggregate, since the energy levels of the molecular orbitals are close, the carrier transport property can be enhanced.

[0226] For example, the active layer 183 is preferably formed by co-evaporating an n-type semiconductor and a p-type semiconductor.

[0227] The layer 186 that also serves as the light-emitting layer and the active layer is preferably formed using the above-described light-emitting substance, n-type semiconductor, and p-type semiconductor.

[0228] For the positive hole injection layer 181, the positive 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 186 that also serves as the light emitting layer and the active layer, either a low molecular compound or a high molecular compound can be used, and they may contain an inorganic compound. Each layer can be formed by methods such as vapor deposition (including vacuum vapor deposition), transfer method, printing method, inkjet method, coating method, etc.

[0229] Hereinafter, with reference to FIGS. 17 to 19, the detailed configurations of the light emitting element and the light receiving and emitting element included in the display device according to one aspect of the present invention will be described.

[0230] The display device according to one aspect of the present invention may be any of a top emission type that emits light in a direction opposite to the substrate on which the light emitting element is formed, a bottom emission type that emits light on the substrate side where the light emitting element is formed, and a dual emission type that emits light on both sides.

[0231] In FIGS. 17 to 19, a top emission type display device will be described as an example.

[0232] [Configuration Example 1] The display devices shown in FIGS. 17A and 17B include a light emitting element 347B that emits blue (B) light, a light emitting element 347G that emits green (G) light, and a light receiving and emitting element 347SR that emits red (R) light and has a light receiving function, via a layer 355 having a transistor on a substrate 151.

[0233] FIG. 17A shows a case where the light receiving and emitting element 347SR functions as a light emitting element. FIG. 17A shows an example in which the light emitting element 347B emits blue light, the light emitting element 347G emits green light, and the light receiving and emitting element 347SR emits red light.

[0234] FIG. 17B shows a case where the light receiving and emitting element 347SR functions as a light receiving element. FIG. 17B shows an example in which the light receiving and emitting element 347SR detects the blue light emitted by the light emitting element 347B and the green light emitted by the light emitting element 347G.

[0235] The light-emitting element 347B, the light-emitting element 347G, and the light-receiving and emitting element 347SR each have a pixel electrode 191 and a common electrode 115. In the present embodiment, a case where the pixel electrode 191 functions as an anode and the common electrode 115 functions as a cathode will be described as an example.

[0236] In the present embodiment, similar to the light-emitting element, in the light-receiving and emitting element 347SR as well, it will be described that the pixel electrode 191 functions as an anode and the common electrode 115 functions as a cathode. That is, the light-receiving and emitting element 347SR can detect the light incident on the light-receiving and emitting element 347SR by applying a reverse bias between the pixel electrode 191 and the common electrode 115 and driving it.

[0237] The common electrode 115 is commonly used for the light-emitting element 347B, the light-emitting element 347G, and the light-receiving and emitting element 347SR.

[0238] The materials, film thicknesses, etc. of the pair of electrodes of the light-emitting element 347B, the light-emitting element 347G, and the light-receiving and emitting element 347SR can be made equal. Thereby, the manufacturing cost of the display device can be reduced and the manufacturing process can be simplified.

[0239] The configuration of the display device shown in FIGS. 17A and 17B will be specifically described.

[0240] The light-emitting element 347B has a buffer layer 192B, a light-emitting layer 193B, and a buffer layer 194B in this order on the pixel electrode 191. The light-emitting layer 193B has a light-emitting substance that emits blue light. The light-emitting element 347B has a function of emitting blue light.

[0241] The light-emitting element 347G has a buffer layer 192G, a light-emitting layer 193G, and a buffer layer 194G in this order on the pixel electrode 191. The light-emitting layer 193G has a light-emitting substance that emits green light. The light-emitting element 347G has a function of emitting green light.

[0242] The light-emitting and light-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 has a light-emitting substance that emits red light. The active layer 183 has an organic compound that absorbs light with a shorter wavelength than red light (for example, one or both of green light and blue light). Note that an organic compound that absorbs not only visible light but also ultraviolet light may be used for the active layer 183. The light-emitting and light-receiving element 347SR has a function of emitting red light. The light-emitting and light-receiving element 347SR preferably has a function of detecting the light emission of at least one of the light-emitting element 347G and the light-emitting element 347B, and more preferably has a function of detecting the light emission of both of them.

[0243] The active layer 183 preferably has an organic compound that hardly absorbs red light and absorbs light with a shorter wavelength than red light. Thereby, the light-emitting and light-receiving element 347SR can have a function of efficiently emitting red light and a function of accurately detecting light with a shorter wavelength than red light.

[0244] 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 stacked structure.

[0245] In the display device shown in FIGS. 17A and 17B, the buffer layer, the active layer, and the light-emitting layer are layers that are separately formed for each element.

[0246] The buffer layers 192R, 192G, and 192B (hereinafter also collectively referred to as the buffer layer 192) can each have one or both of a hole injection layer and a hole transport layer. Further, the buffer layers 192R, 192G, and 192B may have an electron blocking layer. The buffer layers 194B, 194G, and 194R (hereinafter also collectively referred to as the buffer layer 194) can each have one or both of an electron injection layer and an electron transport layer. Further, the buffer layers 194R, 194G, and 194B may have a hole blocking layer. Note that for the materials and the like of each layer constituting the light-emitting element, reference can be made to the description of each layer constituting the above-described light-emitting and light-receiving element.

[0247] [Configuration Example 2] As shown in FIGS. 18A and 18B, the light-emitting elements 347B, 347G, and the light-emitting and light-receiving element 347SR may have a common layer between a pair of electrodes. Thereby, a light-emitting and light-receiving element can be incorporated into a display device without significantly increasing the manufacturing process.

[0248] The light-emitting elements 347B, 347G, and the light-emitting and light-receiving element 347SR shown in FIG. 18A have a common layer 112 and a common layer 114 in addition to the configuration shown in FIGS. 17A and 17B.

[0249] The light-emitting elements 347B, 347G, and the light-emitting and light-receiving element 347SR shown in FIG. 18B are different from the configuration shown in FIGS. 17A and 17B in that they do not have the buffer layers 192R, 192G, 192B and the buffer layers 194R, 194G, 194B, but have a common layer 112 and a common layer 114.

[0250] The common layer 112 can have one or both of a hole injection layer and a hole transport layer. The common layer 114 can have one or both of an electron injection layer and an electron transport layer.

[0251] The common layer 112 and the common layer 114 may each have a single-layer structure or a stacked structure.

[0252] [Configuration Example 3] The display device shown in FIG. 19A is an example in which the stacked structure shown in FIG. 16C is applied to the light-emitting and light-receiving element 347SR.

[0253] The light-emitting and light-receiving element 347SR has, on the 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.

[0254] 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.

[0255] The light-emitting element 347G has, on the pixel electrode 191, 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 in this order.

[0256] The light-emitting element 347B has, on the pixel electrode 191, 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 in this order.

[0257] It is preferable that a microcavity structure is applied to the light-emitting element included in the display device of the present embodiment. Therefore, one of the pair of electrodes included in the light-emitting element is preferably an electrode having transparency and reflectivity with respect to visible light (semi-transmissive / semi-reflective electrode), and the other is preferably an electrode having reflectivity with respect to visible light (reflective electrode). By having a microcavity structure, the light emitted from the light-emitting layer can be resonated between both electrodes, and the light emitted from the light-emitting element can be enhanced.

[0258] Note that the semi-transmissive / semi-reflective electrode can have a laminated structure of a reflective electrode and an electrode having transmissivity with respect to visible light (also referred to as a transparent electrode). In this specification and the like, the reflective electrode that functions as a part of the semi-transmissive / semi-reflective electrode may be described as a pixel electrode or a common electrode, and the transparent electrode may be described as an optical adjustment layer. However, it can sometimes be said that the transparent electrode (optical adjustment layer) also has a function as a pixel electrode or a common electrode.

[0259] The light transmittance of the transparent electrode shall be 40% or more. For example, for the light-emitting element, it is preferable to use an electrode having a transmittance of 40% or more for each of 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). Further, the reflectance of each of visible light and near-infrared light of the semi-transmissive / semi-reflective electrode shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The reflectance of each of visible light and near-infrared light of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. Further, the resistivity of these electrodes is preferably 1×10 -2 Ω·cm or less.

[0260] The hole transport layers 182B, 182G, and 182R may each have a function as an optical adjustment layer. Specifically, for 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 becomes an optical distance that enhances blue light. Similarly, for 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 becomes an optical distance that enhances green light. And for the light-emitting and receiving 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 becomes an optical distance that enhances red light. The layer used as the optical adjustment layer is not limited to the hole transport layer. Note that in the case where the semi-transmissive / semi-reflective electrode has a laminated structure of a reflective electrode and a transparent electrode, the optical distance between the pair of electrodes indicates the optical distance between the pair of reflective electrodes.

[0261] [Configuration Example 4] The display device shown in FIG. 19B is an example in which the laminated structure shown in FIG. 16D is applied to the light-emitting and receiving element 347SR.

[0262] The light-emitting element 347SR has 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 on the pixel electrode 191 in this order.

[0263] 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.

[0264] 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 the pixel electrode 191 in this order.

[0265] 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 the pixel electrode 191 in this order.

[0266] The hole transport layer is provided in the light-emitting element 347G and the light-emitting element 347B, and is not provided in the light-emitting and receiving element 347SR. Thus, in addition to the active layer and the light-emitting layer, there may be a layer provided only in one of the light-emitting element and the light-emitting and receiving element.

[0267] Hereinafter, with reference to FIGS. 20 to 25, the detailed configuration of the display device according to one aspect of the present invention will be described.

[0268] [Display device 310A] Cross-sectional views of the display device 310A are shown in FIGS. 20A and 20B.

[0269] The display device 310A includes a light-emitting element 190B, a light-emitting element 190G, and a light-emitting and receiving element 190SR.

[0270] The light-emitting element 190B includes 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.

[0271] The light-emitting element 190G includes 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.

[0272] The light-emitting and light-receiving element 190SR includes 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 and light-receiving element 190SR has a function of emitting red light 321R and a function of detecting light 322.

[0273] FIG. 20A shows a case where the light-emitting and light-receiving element 190SR functions as a light-emitting element. FIG. 20A shows an example in which the light-emitting element 190B emits blue light, the light-emitting element 190G emits green light, and the light-emitting and light-receiving element 190SR emits red light.

[0274] FIG. 20B shows a case where the light-emitting and light-receiving element 190SR functions as a light-receiving element. FIG. 20B shows an example in which the light-emitting and light-receiving element 190SR detects the blue light emitted by the light-emitting element 190B and the green light emitted by the light-emitting element 190G.

[0275] The pixel electrode 191 is located on the insulating layer 214. The end of the pixel electrode 191 is covered by the partition wall 216. Two adjacent pixel electrodes 191 are electrically insulated from each other by the partition wall 216 (also referred to as electrically separated).

[0276] As the partition wall 216, an organic insulating film is suitable. Examples of materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimide amide resin, siloxane resin, benzocyclobutene-based 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.

[0277] The light receiving and emitting element 310A has a light receiving and emitting element 190SR, a light emitting element 190G, a light emitting element 190B, a transistor 342, etc. between a pair of substrates (substrate 151 and substrate 152).

[0278] The light receiving and emitting element 190SR has a function of detecting light. Specifically, the light receiving and emitting element 190SR is a photoelectric conversion element that receives the light 322 incident from the outside of the display device 310A and converts it into an electrical signal. The light 322 can also be the light reflected by the object from the light emission of one or both of the light emitting elements 190G and 190B. Further, the light 322 may be incident on the light receiving and emitting element 190SR through a lens.

[0279] The light emitting elements 190G and 190B have a function of emitting visible light. Specifically, the light emitting elements 190G and 190B are electroluminescent elements that emit light toward the substrate 152 side by applying a voltage between the pixel electrode 191 and the common electrode 115 (see the light 321G and the light 321B).

[0280] The buffer layer 192, the light emitting layer 193, and the buffer layer 194 can also be referred to as an organic layer (a layer containing an organic compound) or an EL layer. The pixel electrode 191 preferably has a function of reflecting visible light. The common electrode 115 has a function of transmitting visible light.

[0281] 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 the light emitting element or the light receiving and emitting element.

[0282] It is preferable that at least a part of the circuit electrically connected to the light receiving and emitting element 190SR is formed of the same material and in the same process as the circuit electrically connected to the light emitting elements 190G and 190B. Thereby, compared with the case where the two circuits are formed separately, the thickness of the display device can be reduced, and the manufacturing process can be simplified.

[0283] The light-emitting element 190SR, the light-emitting element 190G, and the light-emitting element 190B are each preferably covered with a protective layer 195. In FIG. 20A and the like, the protective layer 195 is provided in contact with the common electrode 115. By providing the protective layer 195, the entry of impurities into the light-emitting and receiving element 190SR and the light-emitting elements of each color can be suppressed, and the reliability of the light-emitting and receiving element 190SR and the light-emitting elements of each color can be improved. Further, the protective layer 195 and the substrate 152 are bonded together by an adhesive layer 142.

[0284] A light-shielding layer BM is provided on the surface of the substrate 152 on the side of the substrate 151. The light-shielding layer BM has openings at positions overlapping the light-emitting element 190G and the light-emitting element 190B, and at positions overlapping the light-emitting and receiving element 190SR. In this specification and the like, the position overlapping the light-emitting element 190G or the light-emitting element 190B specifically refers to the position overlapping the light-emitting region of the light-emitting element 190G or the light-emitting element 190B. Similarly, the position overlapping the light-emitting and receiving element 190SR specifically refers to the position overlapping the light-emitting region and the light-receiving region of the light-emitting and receiving element 190SR.

[0285] As shown in FIG. 20B, the light-emitting and receiving element 190SR can detect the light reflected by the object from the light emission of the light-emitting element 190G or the light-emitting element 190B. However, the light emission of the light-emitting element 190G or the light-emitting element 190B may be reflected within the display device 310A and incident on the light-emitting and receiving element 190SR without passing through the object. The light-shielding layer BM can suppress the influence of such stray light. For example, when the light-shielding layer BM is not provided, the light 323 emitted from the light-emitting element 190G may be reflected by the substrate 152, and the reflected light 324 may be incident on the light-emitting and receiving element 190SR. By providing the light-shielding layer BM, the incidence of the reflected light 324 on the light-emitting and receiving element 190SR can be suppressed. Thereby, noise can be reduced and the sensitivity of the sensor using the light-emitting and receiving element 190SR can be increased.

[0286] As the light-shielding layer BM, a material that blocks light emission from the light-emitting element can be used. The light-shielding layer BM preferably absorbs visible light. As the light-shielding layer BM, for example, a black matrix can be formed 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.

[0287] [Display device 310B] The display device 310B shown in FIG. 21A is different from the display device 310A in that the light-emitting element 190G, the light-emitting element 190B, and the light-emitting and receiving element 190SR do not have the buffer layer 192 and the buffer layer 194 respectively, but have the common layer 112 and the common layer 114. In the description of the display device hereinafter, the description of the same configuration as the previously described display device may be omitted.

[0288] Note that the laminated structures of the light-emitting element 190B, the light-emitting element 190G, and the light-emitting and receiving element 190SR are not limited to the configurations shown in the display devices 310A and 310B. For each element, for example, the laminated structures shown in FIGS. 16 to 19 can be appropriately applied.

[0289] [Display device 310C] The display device 310C shown in FIG. 21B is different from the display device 310B 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.

[0290] The substrate 153 and the insulating layer 212 are bonded together by the adhesive layer 155. The substrate 154 and the protective layer 195 are bonded together by the adhesive layer 142.

[0291] The display device 310C is configured to be manufactured by transferring an insulating layer 212, a transistor 342, a light-emitting and receiving element 190SR, a light-emitting element 190G, a light-emitting element 190B, etc., formed on a manufacturing substrate onto a substrate 153. The substrate 153 and the substrate 154 preferably each have flexibility. Thereby, the flexibility of the display device 310C can be enhanced. For example, it is preferable to use resin for each of the substrate 153 and the substrate 154.

[0292] As the substrate 153 and the substrate 154, 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. can be used. Glass having a thickness sufficient to have flexibility may be used for one or both of the substrate 153 and the substrate 154.

[0293] For the substrate included in the display device of the present embodiment, a film having high optical isotropy may be used. Examples of the film having high optical isotropy include triacetyl cellulose (TAC, also referred to as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0294] Hereinafter, with reference to FIGS. 22 to 25, a more detailed configuration of the display device according to one aspect of the present invention will be described.

[0295] [Display device 100A] FIG. 22 shows a perspective view of the display device 100A, and FIG. 23 shows a cross-sectional view of the display device 100A.

[0296] The display device 100A has a configuration in which the substrate 152 and the substrate 151 are bonded together. In FIG. 22, the substrate 152 is indicated by a dashed line.

[0297] The display device 100A includes a display unit 162, a circuit 164, a wiring 165, etc. FIG. 22 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. 22 can also be referred to as a display module having the display device 100A, the IC, and the FPC.

[0298] As the circuit 164, for example, a scanning line driving circuit can be used.

[0299] 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 are input to the wiring 165 from the IC 173.

[0300] FIG. 22 shows an example in which an IC 173 is provided on the substrate 151 by a COG (Chip On Glass) method or a COF (Chip on Film) method, etc. As the IC 173, for example, an IC having a scanning line driving circuit or a signal line driving circuit can be applied. Note that the display device 100A and the display module may be configured without an IC. Also, the IC may be mounted on the FPC by a COF method or the like.

[0301] FIG. 23 shows an example of a cross section when a part of the region including the FPC 172, a part of the region including the circuit 164, a part of the region including the display unit 162, and a part of the region including the end portion of the display device 100A shown in FIG. 22 are each cut.

[0302] The display device 100A shown in FIG. 23 has 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 and receiving element 190SR, etc. between the substrate 151 and the substrate 152.

[0303] The substrate 152 and the insulating layer 214 are adhered via an adhesive layer 142. For encapsulating the light-emitting element 190B, the light-emitting element 190G, and the light-receiving and emitting element 190SR, a solid encapsulation structure, a hollow encapsulation structure, or the like can be applied. In FIG. 23, the space 143 surrounded by the substrate 152, the adhesive layer 142, and the insulating layer 214 is filled with an inert gas (such as nitrogen or argon), and a hollow encapsulation structure is applied. The adhesive layer 142 may be provided so as to overlap with the light-emitting element 190B, the light-emitting element 190G, and the light-receiving and emitting element 190SR. Further, 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.

[0304] The light-emitting element 190B has a stacked 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 stacked in this order from the insulating layer 214 side. The pixel electrode 191 is connected to a conductive layer 222b included in the transistor 207 through an opening provided in the insulating layer 214. The transistor 207 has a function of controlling the driving of the light-emitting element 190B. The end portion of the pixel electrode 191 is covered by 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.

[0305] The light-emitting element 190G has a stacked 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 included in the transistor 206 through an opening provided in the insulating layer 214. The transistor 206 has a function of controlling the driving of the light-emitting element 190G.

[0306] The light-receiving and emitting element 190SR has a stacked 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 stacked in this order from the insulating layer 214 side. The pixel electrode 191 is electrically connected to a conductive layer 222b included in 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-receiving and emitting element 190SR.

[0307] The light emitted by the light-emitting element 190B, the light-emitting element 190G, and the light-emitting and receiving element 190SR is emitted toward the substrate 152 side. Further, light is incident on the light-emitting and receiving element 190SR through the substrate 152 and the space 143. It is preferable to use a material having high transmittance for visible light for the substrate 152.

[0308] The pixel electrodes 191 can be manufactured using the same material and the same process. The common layers 112, 114, and the common electrode 115 are commonly used for the light-emitting element 190B, the light-emitting element 190G, and the light-emitting and receiving element 190SR. The light-emitting and receiving 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. Further, the light-emitting element 190B, the light-emitting element 190G, and the light-emitting and receiving element 190SR can have the same configuration except that the configurations of the active layer 183 and the light-emitting layers 193 of each color are different. Thereby, a light-receiving function can be added to the display unit 162 of the display device 100A without significantly increasing the manufacturing process.

[0309] A light-shielding layer BM is provided on the surface of the substrate 152 on the substrate 151 side. The light-shielding layer BM has openings at positions overlapping with the light-emitting element 190B, the light-emitting element 190G, and the light-emitting and receiving element 190SR, respectively. By providing the light-shielding layer BM, the range in which the light-emitting and receiving element 190SR detects light can be controlled. Further, by having the light-shielding layer BM, it is possible to suppress light from directly entering the light-emitting and receiving element 190SR from the light-emitting element 190G or the light-emitting element 190B without passing through an object. Therefore, a sensor with less noise and high sensitivity can be realized.

[0310] The transistors 201, 205, 206, and 207 are all formed on the substrate 151. These transistors can be manufactured using the same material and the same process.

[0311] On the substrate 151, an insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided in this order. A part of the insulating layer 211 functions as a gate insulating layer of each transistor. A part of the insulating layer 213 functions as a gate insulating layer of each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and has a function as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistor are not limited, and each may be a single layer or two or more layers.

[0312] It is preferable to use a material in which impurities such as water and hydrogen hardly diffuse in at least one of the insulating layers covering the transistor. Thereby, the insulating layer can function as a barrier layer. With such a configuration, diffusion of impurities from the outside into the transistor can be effectively suppressed, and the reliability of the display device can be improved.

[0313] As the insulating layer 211, the insulating layer 213, and the insulating layer 215, it is preferable to use an inorganic insulating film respectively. As the inorganic insulating film, for example, an inorganic insulating film such as a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, or an aluminum nitride film can be used. Further, an hafnium oxide film, a hafnium oxynitride film, a hafnium nitride oxide film, a 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, etc. may be used. Further, two or more of the above-described insulating films may be laminated and used. Note that an underlayer film may be provided between the substrate 151 and the transistor. The above-described inorganic insulating film can also be used for the underlayer film.

[0314] Here, the organic insulating film often has lower barrier properties than the inorganic insulating film. Therefore, the organic insulating film preferably has an opening near the end of the display device 100A. This can suppress the entry of impurities from the end of the display device 100A through the organic insulating film. Alternatively, the organic insulating film may be formed such that the end of the organic insulating film is inside the end of the display device 100A so that the organic insulating film is not exposed at the end of the display device 100A.

[0315] An organic insulating film is suitable for the insulating layer 214 that functions as a planarization layer. Examples of materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimide amide resin, siloxane resin, benzocyclobutene-based resin, phenol resin, and precursors of these resins.

[0316] In the region 228 shown in FIG. 23, an opening is formed in the insulating layer 214. This can suppress the entry of impurities from the outside into the display unit 162 through the insulating layer 214 even when an organic insulating film is used for the insulating layer 214. Therefore, the reliability of the display device 100A can be enhanced.

[0317] The transistor 201, the transistor 205, the transistor 206, and the transistor 207 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 given to a plurality of 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.

[0318] The structure of the transistor included in the display device of the present embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverse staggered transistor, or the like can be used. Also, either a top gate type or a bottom gate type transistor structure may be used. Alternatively, gates may be provided above and below the semiconductor layer in which the channel is formed.

[0319] For transistors 201, 205, 206, and 207, a configuration is applied in which the semiconductor layer in which the channel is formed is sandwiched between two gates. The transistor may be driven by connecting the two gates and supplying the same signal thereto. 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 supplying a potential for driving to the other.

[0320] The crystallinity of the semiconductor material used for the transistor is also not particularly limited, and any of an amorphous semiconductor, a single crystal semiconductor, or a semiconductor having crystallinity other than a single crystal (microcrystalline semiconductor, polycrystalline semiconductor, or semiconductor having a crystal region in part) may be used. It is preferable to use a single crystal semiconductor or a semiconductor having crystallinity because deterioration of transistor characteristics can be suppressed.

[0321] The semiconductor layer of the transistor preferably has a metal oxide (also referred to as an oxide semiconductor). Alternatively, the semiconductor layer of the transistor may have silicon. Examples of the silicon include amorphous silicon, crystalline silicon (such as low-temperature polysilicon, single crystal silicon, etc.).

[0322] The semiconductor layer preferably contains, for example, indium, one or more elements M (where M is 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.

[0323] In particular, as the semiconductor layer, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (IGZO). 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.

[0324] 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 the atomic ratio of the metal elements in such an In-M-Zn oxide include compositions such as In:M:Zn = 1:1:1 or in the vicinity thereof, In:M:Zn = 1:1:1.2 or in the vicinity thereof, In:M:Zn = 2:1:3 or in the vicinity thereof, In:M:Zn = 3:1:2 or in the vicinity thereof, In:M:Zn = 4:2:3 or in the vicinity thereof, In:M:Zn = 4:2:4.1 or in the vicinity thereof, In:M:Zn = 5:1:3 or in the vicinity thereof, In:M:Zn = 5:1:6 or in the vicinity thereof, In:M:Zn = 5:1:7 or in the vicinity thereof, In:M:Zn = 5:1:8 or in the vicinity thereof, In:M:Zn = 10:1:3 or in the vicinity thereof, In:M:Zn = 6:1:6 or in the vicinity thereof, In:M:Zn = 5:2:5 or in the vicinity thereof, etc. The composition in the vicinity means including a range of ±30% of the desired atomic ratio.

[0325] For example, when the atomic ratio is described as In:Ga:Zn = 4:2:3 or a composition in the vicinity thereof, when the atomic ratio of In is 4, it includes cases where the atomic ratio of Ga is 1 or more and 3 or less, and the atomic ratio of Zn is 2 or more and 4 or less. Further, when the atomic ratio is described as In:Ga:Zn = 5:1:6 or a composition in the vicinity thereof, when the atomic ratio of In is 5, it includes cases where the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is 5 or more and 7 or less. Further, when the atomic ratio is described as In:Ga:Zn = 1:1:1 or a composition in the vicinity thereof, when the atomic ratio of In is 1, it includes cases where the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is greater than 0.1 and 2 or less.

[0326] The transistors included in circuit 164 and the transistors included in display unit 162 may have the same structure or different structures. The structures of the plurality of transistors included in circuit 164 may all be the same or there may be two or more types. Similarly, the structures of the plurality of transistors included in display unit 162 may all be the same or there may be two or more types.

[0327] A connection portion 204 is provided in a region of substrate 151 where substrate 152 does not overlap. In connection portion 204, wiring 165 is electrically connected to FPC 172 via conductive layer 166 and connection layer 242. On the upper surface of connection portion 204, conductive layer 166 obtained by processing the same conductive film as pixel electrode 191 is exposed. Thereby, connection portion 204 and FPC 172 can be electrically connected via connection layer 242.

[0328] Various optical members can be arranged outside substrate 152. Examples of the optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an antireflection layer, and a condensing film. Further, outside substrate 152, an antistatic film for suppressing dust adhesion, a water-repellent film for making dirt less likely to adhere, a hard coat film for suppressing the occurrence of scratches during use, a shock absorption layer, etc. may be arranged.

[0329] For the substrate 151 and the substrate 152, glass, quartz, ceramic, sapphire, resin, etc. can be used respectively. When using a flexible material for the substrate 151 and the substrate 152, the flexibility of the display device can be enhanced.

[0330] As the adhesive layer, various curable adhesives such as photocurable adhesives such as ultraviolet curable type, reaction curable adhesives, thermosetting adhesives, anaerobic adhesives, etc. can be used. Examples of these adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, EVA (ethylene vinyl acetate) resin, etc. In particular, materials with low moisture permeability such as epoxy resin are preferred. Also, a two-component mixed resin may be used. Also, an adhesive sheet or the like may be used.

[0331] As the connection layer, an anisotropic conductive film (ACF: Anisotropic Conductive Film), an anisotropic conductive paste (ACP: Anisotropic Conductive Paste), etc. can be used.

[0332] As materials that can be used for the conductive layers such as various wirings and electrodes constituting the display device, in addition to the gate, source, and drain of the transistor, metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, and alloys mainly composed of the said metals, etc. can be mentioned. Films containing these materials can be used as a single layer or in a laminated structure.

[0333] As the conductive material having translucency, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, or graphene can be used. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing the metal materials can be used. Alternatively, nitrides of the metal materials (for example, titanium nitride) may be used. When using metal materials, alloy materials (or their nitrides), it is preferable to make them thin enough to have translucency. Further, a laminated film of the above materials can be used as the conductive layer. For example, using a laminated film of an alloy of silver and magnesium and indium tin oxide is preferable because the conductivity can be enhanced. These can also be used for conductive layers such as various wirings and electrodes constituting the display device, and conductive layers (conductive layers functioning as pixel electrodes, common electrodes, etc.) of light-emitting elements and light-emitting and receiving elements.

[0334] Examples of the insulating material 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.

[0335] [Display device 100B] FIG. 24 shows a cross-sectional view of the display device 100B.

[0336] The display device 100B mainly differs from the display device 100A in that it has a protective layer 195. Detailed description of the same configuration as that of the display device 100A will be omitted.

[0337] By providing the protective layer 195 that covers the light-emitting element 190B, the light-emitting element 190G, and the light-emitting and receiving element 190SR, it is possible to suppress the entry of impurities such as water into the light-emitting element 190B, the light-emitting element 190G, and the light-emitting and receiving element 190SR, and improve the reliability of the light-emitting element 190B, the light-emitting element 190G, and the light-emitting and receiving element 190SR.

[0338] In the region 228 near the end of the display device 100B, it is preferable that the insulating layer 215 and the protective layer 195 are in contact with each other through the opening of 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 are in contact with each other. Thereby, it is possible to suppress the entry of impurities into the display unit 162 from the outside through the organic insulating film. Therefore, the reliability of the display device 100B can be enhanced.

[0339] The protective layer 195 may be a single layer or a laminated structure. For example, the protective layer 195 may have 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. At this time, it is preferable that the end of the inorganic insulating film extends outside the end of the organic insulating film.

[0340] Furthermore, a lens may be provided in a region overlapping the light-emitting and light-receiving element 190SR. Thereby, the sensitivity and accuracy of the sensor using the light-emitting and light-receiving element 190SR can be enhanced.

[0341] 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.

[0342] Specifically, a resin containing chlorine, bromine, or iodine, a resin containing heavy metal atoms, a resin containing an aromatic ring, a resin containing sulfur, etc. can be used for the lens. Alternatively, a material containing a resin and nanoparticles of a material having a higher refractive index than the resin can be used for the lens. Titanium oxide or zirconium oxide, etc. can be used for the nanoparticles.

[0343] In addition, cerium oxide, hafnium oxide, lanthanum oxide, magnesium oxide, niobium oxide, tantalum oxide, titanium oxide, yttrium oxide, zinc oxide, an oxide containing indium and tin, or an oxide containing indium, gallium, and zinc can be used for the lens. Alternatively, zinc sulfide or the like can be used for the lens.

[0344] In addition, in 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 so as to overlap with the light-emitting element 190B, the light-emitting element 190G, and the light-emitting and receiving element 190SR, respectively, and a solid-sealing structure is applied to the display device 100B.

[0345] [Display device 100C] FIG. 25A shows a cross-sectional view of the display device 100C.

[0346] The structure of the transistors in the display device 100C is different from that of the display device 100B.

[0347] The display device 100C has transistors 208, 209, and 210 on a substrate 151.

[0348] The transistors 208, 209, and 210 include a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer having 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 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 that covers 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.

[0349] The conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215, respectively. Of the conductive layer 222a and the conductive layer 222b, one functions as a source and the other functions as a drain.

[0350] The pixel electrode 191 of the light-emitting element 190G is electrically connected to one of the pair of low-resistance regions 231n of the transistor 208 through the conductive layer 222b.

[0351] The pixel electrode 191 of the light-receiving and light-emitting element 190SR is electrically connected to the other of the pair of low-resistance regions 231n of the transistor 209 through the conductive layer 222b.

[0352] In FIG. 25A, an example is shown in which the insulating layer 225 covers the upper surface and the side surface of the semiconductor layer. On the other hand, in the transistor 202 shown in FIG. 25B, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 and does not overlap with the low-resistance region 231n. For example, the structure shown in FIG. 25B can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In FIG. 25B, 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 the opening of the insulating layer 215. Further, an insulating layer 218 covering the transistor may be provided.

[0353] Further, the display device 100C is different 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.

[0354] The substrate 153 and the insulating layer 212 are bonded together by the adhesive layer 155. The substrate 154 and the protective layer 195 are bonded together by the adhesive layer 142.

[0355] The display device 100C is configured to be manufactured by transferring an insulating layer 212, transistors 208, 209, 210, a light-emitting and receiving element 190SR, a light-emitting element 190G, etc., formed on a manufacturing substrate, onto a substrate 153. The substrate 153 and the substrate 154 preferably each have flexibility. Thereby, the flexibility of the display device 100C can be enhanced.

[0356] For the insulating layer 212, an inorganic insulating film that can be used for the insulating layer 211, the insulating layer 213, and the insulating layer 215 can be used.

[0357] As described above, in the display device of the present embodiment, a light-emitting and receiving element is provided as an alternative to the light-emitting element in a sub-pixel that exhibits any color. By the light-emitting and receiving element also serving as a light-emitting element and a light-receiving element, a light-receiving function can be imparted to a pixel without increasing the number of sub-pixels included in the pixel. Also, a light-receiving function can be imparted to a pixel without reducing the fineness of the display device, the aperture ratio of each sub-pixel, etc.

[0358] This embodiment can be implemented in appropriate combination with at least a part of other embodiments described in this specification.

[0359] (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.

[0360] The metal oxide preferably contains at least indium or zinc. Particularly preferably, it contains indium and zinc. In addition to those, it is preferably contained aluminum, gallium, yttrium, tin, etc. Also, one or more selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, etc. may be contained.

[0361] In addition, the metal oxide can be formed by a sputtering method, a chemical vapor deposition (CVD) method such as a metal organic chemical vapor deposition (MOCVD) method, an atomic layer deposition (ALD) method, or the like.

[0362] <Classification of crystal structures> Examples of the crystal structure of the oxide semiconductor include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and poly crystal.

[0363] The crystal structure of the film or substrate can be evaluated using an X-ray diffraction (XRD) spectrum. For example, it can be evaluated using the XRD spectrum obtained by grazing-incidence XRD (GIXD) measurement. Note that the GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0364] For example, in a quartz glass substrate, the shape of the peak in the XRD spectrum is almost symmetric about the left and right. On the other hand, in an IGZO film having a crystal structure, the shape of the peak in the XRD spectrum is asymmetric about the left and right. The fact that the shape of the peak in the XRD spectrum is asymmetric about the left and right indicates the presence of crystals in the film or substrate. In other words, if the shape of the peak in the XRD spectrum is not symmetric about the left and right, it cannot be said that the film or substrate is in an amorphous state.

[0365] In addition, the crystal structure of the film or substrate can be evaluated by the diffraction pattern (also referred to as the nano-beam electron diffraction pattern) observed by the nano-beam electron diffraction method (NBED). For example, in the diffraction pattern of a quartz glass substrate, a halo is observed, and it can be confirmed that the quartz glass is in an amorphous state. Also, in the diffraction pattern of an IGZO film formed at room temperature, a spot-like pattern is observed instead of a halo. Therefore, it is presumed that the IGZO film formed at room temperature is in an intermediate state that is neither crystalline nor amorphous, and it cannot be concluded that it is in an amorphous state.

[0366] [[Structure of Oxide Semiconductor]] Note that when focusing on the structure, the oxide semiconductor may be classified differently from the above. For example, the oxide semiconductor can be divided into a single-crystalline oxide semiconductor and other non-single-crystalline oxide semiconductors. Examples of non-single-crystalline oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. In addition, non-single-crystalline oxide semiconductors include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS: amorphous-like oxide semiconductor), amorphous oxide semiconductors, and the like.

[0367] Here, the details of the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described.

[0368] [CAAC-OS] CAAC-OS is an oxide semiconductor having a plurality of crystal regions, and the plurality of crystal regions are such that the c-axis is oriented in a specific direction. Here, the specific direction is the thickness direction of the CAAC-OS film, the normal direction of the surface on which the CAAC-OS film is formed, or the normal direction of the surface of the CAAC-OS film. Further, a crystal region is a region having periodicity in the atomic arrangement. When the atomic arrangement is regarded as a lattice arrangement, the crystal region is also a region where the lattice arrangements are aligned. Furthermore, CAAC-OS has a region where a plurality of crystal regions are connected in the a-b plane direction, and this region may have strain. Here, strain refers to a portion where the orientation of the lattice arrangement changes between a region where the lattice arrangements are aligned and another region where the lattice arrangements are aligned in a region where a plurality of crystal regions are connected. That is, CAAC-OS is an oxide semiconductor in which the c-axis is oriented and there is no obvious orientation in the a-b plane direction.

[0369] Each of the plurality of crystal regions is composed of one or a plurality of minute crystals (crystals having a maximum diameter of less than 10 nm). When a crystal region is composed of one minute crystal, the maximum diameter of the crystal region is less than 10 nm. Further, when a crystal region is composed of a number of minute crystals, the size of the crystal region may be on the order of several tens of nm.

[0370] Also, in an In-M-Zn oxide (the element M is one or more selected from aluminum, gallium, yttrium, tin, titanium, etc.), 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, In layer) and a layer containing the element M, zinc (Zn), and oxygen (hereinafter, (M,Zn) layer) are laminated. Here, indium and the element M are mutually substitutable. Therefore, the (M,Zn) layer may contain indium. Further, the In layer may contain the element M. Note that the In layer may also contain Zn. The layered structure is observed as a lattice image, for example, in a high-resolution TEM (Transmission Electron Microscope) image.

[0371] When performing structural analysis on a CAAC-OS film using, for example, an XRD apparatus, in out-of-plane XRD measurement using θ / 2θ scan, a peak indicating c-axis orientation is detected at 2θ = 31° or in its vicinity. Note that the position of the peak indicating c-axis orientation (the value of 2θ) may vary depending on the type and composition of the metal elements constituting CAAC-OS.

[0372] Also, for example, in the electron diffraction pattern of a CAAC-OS film, a plurality of bright spots (spots) are observed. Note that one spot and another spot are observed at point-symmetric positions with the spot of the incident electron beam transmitted through the sample (also called the direct spot) as the center of symmetry.

[0373] When observing the crystal region from the above specific direction, the lattice arrangement within the crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be a non-regular hexagon. Also, in the above distortion, there may be lattice arrangements such as pentagons and heptagons. Note that in CAAC-OS, even near the distortion, a clear grain boundary cannot be confirmed. That is, it can be seen that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is presumably because CAAC-OS can tolerate distortion due to the fact that the arrangement of oxygen atoms is not dense in the a-b plane direction and the interatomic bond distance changes due to the substitution of metal atoms, etc.

[0374] Note that a crystal structure in which a clear grain boundary is confirmed is called a so-called polycrystal. Grain boundaries can become recombination centers and are likely to cause a decrease in the on-current of a transistor and a decrease in the field-effect mobility due to the capture of carriers. Therefore, CAAC-OS in which a clear grain boundary is not confirmed is one of the crystalline oxides having a crystal structure suitable for the semiconductor layer of a transistor. Note that for forming CAAC-OS, a configuration having Zn is preferable. For example, In-Zn oxide and In-Ga-Zn oxide are preferable because they can suppress the generation of grain boundaries more than In oxide.

[0375] CAAC-OS is an oxide semiconductor with high crystallinity and no distinct grain boundaries being confirmed. Therefore, it can be said that in CAAC-OS, a decrease in electron mobility due to grain boundaries is less likely to occur. Also, since the crystallinity of an oxide semiconductor may decrease due to impurity incorporation, defect generation, etc., CAAC-OS can also be said to be an oxide semiconductor with few impurities and defects (such as oxygen deficiencies). Therefore, the physical properties of the oxide semiconductor having CAAC-OS are stable. For this reason, the oxide semiconductor having CAAC-OS is heat-resistant and highly reliable. Also, CAAC-OS is stable against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, when CAAC-OS is used for an OS transistor, it becomes possible to expand the degree of freedom in the manufacturing process.

[0376] [nc-OS] nc-OS has periodicity in the atomic arrangement in a minute region (for example, a region of 1 nm or more and 10 nm or less, particularly a region of 1 nm or more and 3 nm or less). In other words, nc-OS has minute crystals. Since the size of the minute crystals is, for example, 1 nm or more and 10 nm or less, particularly 1 nm or more and 3 nm or less, the minute crystals are also called nanocrystals. Also, nc-OS has no regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is observed in the entire film. Therefore, depending on the analysis method, nc-OS may not be distinguishable from a-like OS or an amorphous oxide semiconductor. For example, when structural analysis is performed on an nc-OS film using an XRD apparatus, no peak indicating crystallinity is detected in the Out-of-plane XRD measurement using θ / 2θ scan. Also, when electron beam diffraction (also called limited field electron beam diffraction) using an electron beam with a probe diameter larger than that of the nanocrystals (for example, 50 nm or more) is performed on an nc-OS film, a diffraction pattern like a halo pattern is observed. On the other hand, when electron beam diffraction (also called nanobeam electron beam diffraction) using an electron beam with a probe diameter close to or smaller than the size of the nanocrystals (for example, 1 nm or more and 30 nm or less) is performed on an nc-OS film, an electron beam diffraction pattern in which a plurality of spots are observed within a ring-shaped region centered on a direct spot may be obtained.

[0377] [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 loose or low-density region. That is, the a-like OS has lower crystallinity compared with the nc-OS and the CAAC-OS. Further, the a-like OS has a higher hydrogen concentration in the film compared with the nc-OS and the CAAC-OS.

[0378] [[Constitution of Oxide Semiconductor]] Next, the details of the above-described CAC-OS will be described. Note that the CAC-OS relates to the material constitution.

[0379] [CAC-OS] The CAC-OS is, for example, a configuration of a material in which elements constituting a metal oxide are unevenly distributed in a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or less, or in the vicinity thereof. In the following, in the metal oxide, a state in which one or more metal elements are unevenly distributed and regions having the metal element are mixed in a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or less, or in the vicinity thereof is also referred to as a mosaic state or a patch state.

[0380] Furthermore, the CAC-OS is a configuration in which materials are separated into a first region and a second region to form a mosaic state, and the first region is distributed in the film (hereinafter also referred to as a cloud state). That is, the CAC-OS is a composite metal oxide having a configuration in which the first region and the second region are mixed.

[0381] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In-Ga-Zn oxide are represented 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. Also, 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. Also, 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.

[0382] Specifically, the first region is a region mainly composed of indium oxide, indium zinc oxide, etc., and the second region is a region mainly composed of gallium oxide, gallium zinc oxide, etc. In other words, the first region can be rephrased as a region mainly composed of In, and the second region can be rephrased as a region mainly composed of Ga.

[0383] In addition, there are cases where a clear boundary between the first region and the second region cannot be observed.

[0384] In addition, the CAC-OS in In-Ga-Zn oxide refers to a structure in which some regions mainly composed of Ga and some regions mainly composed of In are arranged randomly in a mosaic pattern in a material structure containing In, Ga, Zn, and O. Therefore, it is presumed that the CAC-OS has a structure in which metal elements are distributed non-uniformly.

[0385] CAC-OS can be formed by a sputtering method, for example, under conditions where the substrate is not intentionally heated. Also, when forming CAC-OS by the sputtering method, any one or more selected from an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as the film-forming gas. Further, the lower the flow rate ratio of oxygen gas to the total flow rate of the film-forming gas during film formation, the more preferable it is. For example, it is preferable that the flow rate ratio of oxygen gas to the total flow rate of the film-forming gas during film formation is 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0386] Also, for example, in CAC-OS in In-Ga-Zn oxide, it can be confirmed by EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) that the region mainly composed of In (the first region) and the region mainly composed of Ga (the second region) are unevenly distributed and have a mixed structure.

[0387] Here, the first region is a region with higher conductivity compared to the second region. That is, when carriers flow through the first region, the conductivity as a metal oxide is exhibited. Therefore, when the first region is distributed in a cloud-like manner in the metal oxide, a high field-effect mobility (μ) can be realized.

[0388] On the other hand, the second region is a region with higher insulating properties compared to the first region. That is, by the second region being distributed in the metal oxide, the leakage current can be suppressed.

[0389] Therefore, when using CAC-OS in a transistor, the conductivity caused by the first region and the insulating property caused by the second region act complementarily, enabling the function of switching (turning on / off) to be imparted to the CAC-OS. That is, CAC-OS has a conductive function in part of the material and an insulating function in part of the material, and has a semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be enhanced to the maximum extent. Therefore, by using CAC-OS in a transistor, a high on-current (I on ) and a high field-effect mobility (μ), as well as a good switching operation, can be realized.

[0390] In addition, a transistor using CAC-OS has high reliability. Therefore, CAC-OS is optimal for various semiconductor devices including display devices.

[0391] Oxide semiconductors have various structures and each has different characteristics. The oxide semiconductor according to one aspect of the present invention may have two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0392] <Transistor having an oxide semiconductor> Subsequently, the case of using the above oxide semiconductor in a transistor will be described.

[0393] By using the above oxide semiconductor in a transistor, a transistor with a high field-effect mobility can be realized. In addition, a highly reliable transistor can be realized.

[0394] For a transistor, it is preferable to use an oxide semiconductor with a low carrier concentration. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 or less, preferably 1×10 15 cm -3 or less, and more preferably 1×10 13 cm -3Hereinafter, more preferably 1×10 11 cm -3 or less, and even more preferably 1×10 10 cm -3 or less, and 1×10 -9 cm -3 or more. When reducing the carrier concentration of the oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced and the density of defect levels may be reduced. In this specification and the like, a low impurity concentration and a low density of defect levels are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that an oxide semiconductor with a low carrier concentration may be referred to as a high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor.

[0395] In addition, an oxide semiconductor film that is high-purity intrinsic or substantially high-purity intrinsic may have a low trap level density because the density of defect levels is low.

[0396] In addition, the charge trapped in the trap levels of the oxide semiconductor may take a long time to disappear and may behave like a fixed charge. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high trap level density may have unstable electrical characteristics.

[0397] Therefore, in order to stabilize the electrical characteristics of the transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. In addition, 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.

[0398] <Impurity> Here, the influence of each impurity in the oxide semiconductor will be described.

[0399] In an oxide semiconductor, when silicon, carbon, which is one of the Group 14 elements, etc. are contained, 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 (the concentration obtained by secondary ion mass spectrometry (SIMS)) are 2×10 18 atoms / cm 3 or less, preferably 2×10 17 atoms / cm 3 or less.

[0400] In addition, when an alkali metal or an alkaline earth metal is contained in the oxide semiconductor, defect levels may be formed and carriers may be generated. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal tends to have normally-on characteristics. For this reason, the concentration of the alkali metal or the alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 18 atoms / cm 3 or less, preferably 2×10 16 atoms / cm 3 or less.

[0401] In addition, in an oxide semiconductor, when nitrogen is contained, electrons as carriers are generated, the carrier concentration increases, and it tends to be n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Or, when nitrogen is contained in the oxide semiconductor, trap levels 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 5×10 19 atoms / cm 3 less than, preferably 5×10 18 atoms / cm 3 or less, more preferably 1×10 18 atoms / cm 3 or less, even more preferably 5×10 17 atoms / cm 3 or less.

[0402] In addition, since hydrogen contained in the oxide semiconductor reacts with oxygen bonded to metal atoms to form water, oxygen vacancies may be formed. When hydrogen enters these oxygen vacancies, electrons, which are carriers, may be generated. Also, a part of the hydrogen may bond with oxygen bonded to metal atoms to generate electrons, which are carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen tends to have normally-on characteristics. For this reason, it is preferable that hydrogen in the oxide semiconductor is reduced as much as possible. Specifically, in the oxide semiconductor, the hydrogen concentration obtained by SIMS is less than 1×10 20 atoms / cm 3 less than, preferably less than 1×10 19 atoms / cm 3 less than, more preferably less than 5×10 18 atoms / cm 3 less than, even more preferably less than 1×10 18 atoms / cm 3 less than.

[0403] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be imparted.

[0404] This embodiment can be implemented in appropriate combination with at least some of the other embodiments described in this specification.

[0405] (Embodiment 4) In this embodiment, an electronic device according to an aspect of the present invention will be described with reference to FIGS. 26 to 28.

[0406] The electronic device of this embodiment has a display device according to an aspect of the present invention. For example, a display device according to an aspect of the present invention can be applied to the display unit of the electronic device. Since the display device according to an aspect of the present invention has a function of detecting light, biometric authentication can be performed at the display unit, a touch operation (contact or approach) can be detected, and the like. Thereby, the functionality and convenience of the electronic device can be enhanced.

[0407] Examples of electronic devices include, for example, relatively large-screen electronic devices such as television sets, desktop or notebook personal computers, monitors for computers, digital signage, and large game machines such as pachinko machines. In addition, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, portable information terminals, audio playback devices, and the like can be mentioned.

[0408] The electronic device of the present embodiment may have a sensor (including a 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).

[0409] The electronic device of the present embodiment can have various functions. For example, it can have a function of displaying various information (such as still images, moving images, text images, etc.) on a display unit, a touch panel function, a function of displaying a calendar, date, or time, a function of executing various software (programs), a wireless communication function, a function of reading programs or data recorded on a recording medium, and the like.

[0410] The electronic device 6500 shown in FIG. 26A is a portable information terminal that can be used as a smartphone.

[0411] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, buttons 6504, a speaker 6505, a microphone 6506, a camera 6507, a light source 6508, and the like. The display unit 6502 has a touch panel function.

[0412] The display device of one aspect of the present invention can be applied to the display unit 6502.

[0413] FIG. 26B is a schematic cross-sectional view including an end portion on the microphone 6506 side of the housing 6501.

[0414] A protective member 6510 having translucency is provided on the display surface side of the housing 6501, and a display panel 6511, an optical member 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.

[0415] On the protective member 6510, the display panel 6511, the optical member 6512, and the touch sensor panel 6513 are fixed by an adhesive layer (not shown).

[0416] In a region 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 portion. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on the printed circuit board 6517.

[0417] A flexible display according to an aspect of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. Further, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted while suppressing the thickness of the electronic device. Further, by folding back a part of the display panel 6511 and arranging the connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow bezel can be realized.

[0418] By using a display device according to an aspect of the present invention for the display panel 6511, imaging can be performed by the display unit 6502. For example, a fingerprint can be imaged by the display panel 6511 and fingerprint authentication can be performed.

[0419] Since the display unit 6502 further has a touch sensor panel 6513, a touch panel function can be imparted to the display unit 6502. As the touch sensor panel 6513, various methods such as a capacitance method, a resistive film method, a surface acoustic wave method, an infrared method, an optical method, and a pressure-sensitive method can be used. Alternatively, the display panel 6511 may function as a touch sensor, and in that case, the touch sensor panel 6513 may not be provided.

[0420] FIG. 27A shows an example of a television apparatus. In the television apparatus 7100, a display unit 7000 is incorporated in a housing 7101. Here, a configuration in which the housing 7101 is supported by a stand 7103 is shown.

[0421] The display device according to one aspect of the present invention can be applied to the display unit 7000.

[0422] The operation of the television apparatus 7100 shown in FIG. 27A can be performed by an operation switch provided in the housing 7101, a separate remote control operation unit 7111, or the like. Alternatively, the display unit 7000 may be provided with a touch sensor, and the television apparatus 7100 may be operated by touching the display unit 7000 with a finger or the like. The remote control operation unit 7111 may have a display unit for displaying information output from the remote control operation unit 7111. Channel and volume operations can be performed by operation keys or a touch panel provided in the remote control operation unit 7111, and the video displayed on the display unit 7000 can be operated.

[0423] Note that the television apparatus 7100 has a configuration including a receiver and a modem. The receiver can receive general television broadcasts. Also, by connecting to a communication network by wire or wirelessly via the modem, one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers) information communication is also possible.

[0424] FIG. 27B shows an example of a notebook personal computer. The notebook personal computer 7200 has a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. A display unit 7000 is incorporated in the housing 7211.

[0425] The display device according to one aspect of the present invention can be applied to the display unit 7000.

[0426] FIGS. 27C and 27D show an example of digital signage.

[0427] The digital signage 7300 shown in FIG. 27C includes a housing 7301, a display unit 7000, a speaker 7303, etc. Furthermore, it can have an LED lamp, operation keys (including a power switch or an operation switch), connection terminals, various sensors, a microphone, etc.

[0428] FIG. 27D 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.

[0429] In FIGS. 27C and 27D, the display device according to an aspect of the present invention can be applied to the display unit 7000.

[0430] The larger the display unit 7000 is, the more information can be provided at one time. Also, the larger the display unit 7000 is, the more easily it catches people's eyes, and for example, the advertising effect can be enhanced.

[0431] By applying a touch panel to the display unit 7000, not only can an image or a video be displayed on the display unit 7000, but also the user can operate it intuitively, which is preferable. Also, when used for applications such as providing route information or traffic information, the usability can be enhanced by intuitive operation.

[0432] Also, as shown in FIGS. 27C and 27D, it is preferable that the digital signage 7300 or the digital signage 7400 can be linked with an information terminal 7311 or an information terminal 7411 such as a smartphone held by the user through wireless communication. For example, the information of the advertisement displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411. Also, by operating the information terminal 7311 or the information terminal 7411, the display on the display unit 7000 can be switched.

[0433] In addition, it is also possible to execute 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). As a result, an unspecified number of users can participate in and enjoy the game simultaneously.

[0434] The electronic devices shown in FIGS. 28A to 28F include a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), connection terminals 9006, a sensor 9007 (including a function for 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.

[0435] The electronic devices shown in FIGS. 28A to 28F have various functions. For example, functions such as displaying various information (still images, moving images, text images, etc.) on the display unit, a touch panel function, a function of displaying a calendar, date or time, a function of controlling processing by various software (programs), a wireless communication function, a function of reading and processing programs or data recorded on a recording medium, etc. can be provided. Note that the functions of the electronic device are not limited to these, and it can have various functions. The electronic device may have a plurality of display units. In addition, a camera or the like may be provided in the electronic device, and it may have functions such as shooting still images, moving images, etc. and storing them in a recording medium (external or built-in to the camera), and displaying the shot images on the display unit.

[0436] Details of the electronic devices shown in FIGS. 28A to 28F will be described below.

[0437] FIG. 28A is a perspective view showing a portable information terminal 9101. The portable information terminal 9101 can be used, for example, as a smartphone. Note that the portable information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, etc. Also, the portable information terminal 9101 can display characters, image information, etc. on its multiple surfaces. FIG. 28A shows an example in which three icons 9050 are displayed. Also, information 9051 indicated by a dashed rectangle can be displayed on other surfaces of the display unit 9001. Examples of the information 9051 include notifications of incoming calls such as e-mail, SNS, and phone calls, titles of e-mail, SNS, etc., sender names, dates and times, battery remaining amounts, antenna reception strengths, etc. Alternatively, icons 9050 etc. may be displayed at the position where the information 9051 is displayed.

[0438] FIG. 28B is a perspective view showing a portable information terminal 9102. The portable information terminal 9102 has a function of displaying information on three or more surfaces of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are respectively displayed on different surfaces. For example, the user can also check the information 9053 displayed at a position where it can be observed from above the portable information terminal 9102 while the portable information terminal 9102 is stored in the breast pocket of a piece of clothing. The user can check the display without taking the portable information terminal 9102 out of the pocket and can, for example, determine whether to answer a call.

[0439] FIG. 28C is a perspective view showing a wristwatch-type portable information terminal 9200. Also, the display unit 9001 is provided with a curved display surface, and display can be performed along the curved display surface. Also, the portable information terminal 9200 can also make a hands-free call by communicating with, for example, a wirelessly communicable headset. Also, the portable information terminal 9200 can perform data transmission and charging mutually with other information terminals via the connection terminal 9006. Note that the charging operation may be performed by wireless power supply.

[0440] 28D to 28F are perspective views showing a foldable mobile information terminal 9201. FIG. 28D is a perspective view of the mobile information terminal 9201 in an unfolded state, FIG. 28F is a perspective view of the mobile information terminal 9201 in a folded state, and FIG. 28E is a perspective view of the mobile information terminal 9201 in a state in the middle of changing from one of FIG. 28D and FIG. 28F to the other. The mobile information terminal 9201 has excellent portability in a folded state, and has excellent viewability of the display due to a seamless wide display area in an unfolded state. 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 radius of curvature of 0.1 mm or more and 150 mm or less.

[0441] This embodiment mode can be implemented by appropriately combining at least a part of it with other embodiment modes described in this specification. [Explanation of symbols]

[0442] Tr1:Transistor:SW1:Switch:SW2:Switch:SW3:Switch:SW4:Switch:SA:Light emitting / receiving element:CS:Capacitor:AL:Wiring:CL:Wiring:WX:Wiring:SL:Wiring:V data : Data potential: V gp :Potential:V gs :Voltage:V off :Potential:V RS :Potential:V sig : Potential: SL1: Wiring: SL2: Wiring: SL3: Wiring: GL: Wiring: SE: Wiring: AEN: Wiring: REN: Wiring: SR: Light emitting element: ELB: Light emitting element: ELG: Light emitting element: M1: Transistor: M2: Transistor: M3: Transistor: M4: Transistor: M5: Transistor: M6: Transistor: 10: Display device: 11: Display unit: 12: Drive circuit unit: 13: Drive circuit unit: 14: Drive circuit unit: 15: Circuit unit: 20R: Pixel: 20B: Pixel: 20G: Pixel: 21R: Circuit: 21B: Circuit: 21G: Circuit: 30: Pixel: 30A: Pixel: 30B: Pixel: 30G: Pixel

Claims

1. comprising first to fourth switches, a first transistor, a capacitor, a light emitting and receiving element, and first to fourth wirings, the first wiring is electrically connected to the gate of the first transistor via the first switch, the second wiring is electrically connected to one of the source and drain of the first transistor via the second switch, the anode of the light emitting and receiving element is electrically connected to the other of the source and drain of the first transistor via the third switch, and the cathode is electrically connected to the third wiring, the fourth wiring is electrically connected to the other of the source and drain of the first transistor via the fourth switch, one electrode of the capacitor is electrically connected to the gate of the first transistor, and the other electrode is electrically connected to the other of the source and drain of the first transistor, a first potential is applied to the second wiring, a second potential lower than the first potential is applied to the third wiring, the light emitting and receiving element has a function of emitting light of a first color and a function of receiving light of a second color and converting it into an electrical signal, in a first period, the first to fourth switches are in a conductive state, a data potential is applied to the first wiring, and a third potential is applied to the fourth wiring, in a second period, the first switch and the fourth switch are in a non-conductive state, and the second switch and the third switch are in a conductive state, in a third period, the first switch, the third switch, and the fourth switch are in a conductive state, the second switch is in a non-conductive state, a fourth potential lower than the first potential is applied to the first wiring, and a fifth potential lower than the second potential is applied to the fourth wiring, in a fourth period, the first to fourth switches are in a non-conductive state, in a fifth period, the first switch and the third switch are in a conductive state, the second switch and the fourth switch are in a non-conductive state, and a sixth potential higher than the second potential is applied to the first wiring, in a sixth period, the first switch and the third switch are in a non-conductive state, and the second switch and the fourth switch are in a conductive state, a display device.

2. A display module having the display device according to claim 1 and a connector or an integrated circuit.

3. The display module according to claim 2, An electronic device having at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, a touch sensor, and an operation button.

Images