Display device, display module and electronic device

Abstract

To increase the definition of a display device with a light detecting function.SOLUTION: A display device includes a plurality of transistors and a light-receiving device in a subpixel. The light-receiving device has a function of emitting light in a first color and a function of receiving light in a second color. One of a source and a drain of a first transistor is electrically connected to a first wire while the other is electrically connected to a gate of a second transistor. One electrode of the light-receiving device is electrically connected to one of a source and a drain of the second transistor, to one of a source and a drain of a third transistor, and to one of a source and a drain of a fifth transistor. One of a source and a drain of a fourth transistor is electrically connected to a second wire while the other is electrically connected to the other of the source and the drain of the third transistor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] 1. Field of the Invention One embodiment of the present invention relates to a display device, a display module, and an electronic device. 1. Field of the Invention One embodiment of the present invention relates to a display device including a light-receiving and light-emitting device (also referred to as a light-emitting element) and a light-emitting device (also referred to as a light-emitting element).

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input / output device (e.g., a touch panel), a driving method thereof, or a manufacturing method thereof. [Background technology]

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

[0004] As a display device, for example, a light-emitting device having a light-emitting device has been developed. A light-emitting device (also called an EL device or an EL element) utilizing the electroluminescence (hereinafter referred to as EL) phenomenon has features such as being easily thin and lightweight, being capable of responding quickly to an input signal, and being capable of being driven by a low-voltage direct current power supply, and is applied to a display device. For example, Patent Document 1 discloses a flexible light-emitting device to which an organic EL device (also called an organic EL element) is applied. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-197522 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of one embodiment of the present invention is to provide a display device having a light detection function.An object of one embodiment of the present invention is to increase the resolution of a display device having a light detection function.An object of one embodiment of the present invention is to provide a highly convenient display device.An object of one embodiment of the present invention is to provide a multifunctional display device.An object of one embodiment of the present invention is to provide a display device with a high aperture ratio.An object of one embodiment of the present invention is to provide a novel display device.

[0007] An object of one embodiment of the present invention is to improve the manufacturing yield of a display device having a light detection function.An object of one embodiment of the present invention is to reduce the number of steps for manufacturing a display device having a light detection function.An object of one embodiment of the present invention is to reduce the manufacturing cost of a display device having a light detection function.

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

[0009] One embodiment of the present invention is a display device including a pixel, a first wiring, a second wiring, and a third wiring. The pixel includes a first subpixel. The first subpixel includes first to eighth transistors, a first capacitor, and a light receiving and emitting device. One of a source and a drain of the first transistor is electrically connected to a first wiring, and the other electrode of the first transistor is electrically connected to a gate of the second transistor and one electrode of the first capacitor. One electrode of the light receiving and emitting device is electrically connected to one of a source and a drain of the second transistor, one of a source and a drain of the third transistor, and one of a source and a drain of the fifth transistor. One of a source and a drain of the fourth transistor is electrically connected to a second wiring, and the other electrode of the source and the drain of the third transistor and the other electrode of the first capacitor. The other of the source and the drain of the fifth transistor is electrically connected to one of a source and a drain of the sixth transistor and a gate of the seventh transistor. One of the source and drain of the seventh transistor is electrically connected to one of the source and drain of the eighth transistor. The other of the source and drain of the eighth transistor is electrically connected to a third wiring. The light emitting and receiving device has a function of emitting light of a first color and a function of receiving light of a second color.

[0010] The first wiring is preferably supplied with a first data potential. The second wiring is preferably supplied with a second data potential during the first period and a reset potential during the second period. The third wiring is preferably supplied with a potential according to charges generated in the light emitting and receiving device.

[0011] The display device of one embodiment of the present invention preferably further includes fourth to eighth wirings. The gate of the first transistor and the gate of the third transistor are preferably electrically connected to the fourth wiring. The gate of the fourth transistor is preferably electrically connected to the fifth wiring. The gate of the fifth transistor is preferably electrically connected to the sixth wiring. The gate of the sixth transistor is preferably electrically connected to the seventh wiring. The gate of the eighth transistor is preferably electrically connected to the eighth wiring.

[0012] The first subpixel preferably further includes a second capacitor. One electrode of the second capacitor is preferably electrically connected to the other of the source and drain of the first transistor, the gate of the second transistor, and one electrode of the first capacitor. The other electrode of the second capacitor is preferably electrically connected to one electrode of the light emitting and receiving device, one of the source and drain of the second transistor, one of the source and drain of the third transistor, and one of the source and drain of the fifth transistor.

[0013] The display device according to one embodiment of the present invention preferably further includes a ninth wiring. The pixel preferably further includes a second subpixel. The second subpixel preferably includes ninth to eleventh transistors and a light-emitting device. One of a source and a drain of the ninth transistor is preferably electrically connected to the ninth wiring, and the other is preferably electrically connected to a gate of the tenth transistor. One electrode of the light-emitting device is preferably electrically connected to one of a source and a drain of the tenth transistor and one of a source and a drain of the eleventh transistor. The light-emitting device preferably has a function of emitting light of a second color.

[0014] The other of the source and drain of the eleventh transistor is preferably electrically connected to the second wiring. Alternatively, the second subpixel preferably further includes a twelfth transistor. It is preferable that one of the source and drain of the twelfth transistor is electrically connected to the second wiring, and the other is electrically connected to the other of the source and drain of the eleventh transistor.

[0015] The light-emitting device preferably has a hole injection layer, a light-emitting layer, and an electron transport layer. The hole injection layer preferably has a first compound and a second compound. The electron transport layer preferably has an electron transporting material. The first compound preferably has electron acceptance for the second compound. The HOMO level of the second compound is preferably -5.7 eV or more and -5.4 eV or less. The electron transporting material has a HOMO level of -6.0 eV or more and an electron mobility of 1 x 10 at a square root of an electric field strength [V / cm] of 600. -7 cm 2 / Vs or more 5×10 -5 cm 2 It is preferable that the value is equal to or less than / Vs.

[0016] Alternatively, the light-emitting device preferably has a light-emitting layer and an electron transport layer. The electron transport layer preferably has an electron transporting material and a first substance. The first substance is preferably a metal, a metal salt, a metal oxide, or an organometallic complex. The electron transport layer preferably has a first region and a second region. The first region and the second region preferably have different concentrations of the first substance.

[0017] The light emitting / receiving device and the light emitting device are preferably provided on the same surface.

[0018] The display device of one embodiment of the present invention is preferably flexible. For example, the first to eighth transistors are preferably provided over a flexible substrate.

[0019] One embodiment of the present invention is a module having a display device having any of the above configurations, and having a connector such as a flexible printed circuit (hereinafter referred to as FPC) or a TCP (Tape Carrier Package) attached, or a module having an integrated circuit (IC) mounted by a COG (Chip On Glass) method or a COF (Chip On Film) method, or the like.

[0020] One embodiment of the present invention is an electronic device including any of the above modules and at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button. Effect of the Invention

[0021] According to one embodiment of the present invention, a display device having a light detection function can be provided. According to one embodiment of the present invention, the resolution of a display device having a light detection function can be increased. According to one embodiment of the present invention, a highly convenient display device can be provided. According to one embodiment of the present invention, a multifunction display device can be provided. According to one embodiment of the present invention, a display device with a high aperture ratio can be provided. According to one embodiment of the present invention, a novel display device can be provided.

[0022] According to one embodiment of the present invention, the manufacturing yield of a display device having a light detection function can be improved. According to one embodiment of the present invention, the number of steps for manufacturing a display device having a light detection function can be reduced. According to one embodiment of the present invention, the manufacturing cost of a display device having a light detection function can be reduced.

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

[0024] [Figure 1] FIG. 1 is a circuit diagram showing an example of a pixel circuit. [Diagram 2]FIG. 2 is a circuit diagram showing an example of a pixel circuit. [Diagram 3] 3A and 3B are diagrams showing an example of a method for driving a display device. [Figure 4] 4A and 4B are timing charts showing an example of a method for driving a display device. [Diagram 5] 5A to 5D are timing charts showing an example of a method for driving a display device. [Figure 6] Figures 6A to 6D are cross-sectional views showing an example of a display device, and Figures 6E to 6G are top views showing an example of a pixel. [Figure 7] 7A to 7D are top views showing an example of a pixel. [Figure 8] 8A to 8E are cross-sectional views showing examples of light receiving and emitting devices. [Figure 9] 9A and 9B are cross-sectional views showing an example of a display device. [Figure 10] 10A and 10B are cross-sectional views showing an example of a display device. [Figure 11] 11A and 11B are cross-sectional views showing an example of a display device. [Figure 12] 12A and 12B are cross-sectional views showing an example of a display device. [Figure 13] 13A and 13B are cross-sectional views showing an example of a display device. [Figure 14] FIG. 14 is a perspective view showing an example of a display device. [Figure 15] FIG. 15 is a cross-sectional view showing an example of a display device. [Figure 16] FIG. 16 is a cross-sectional view showing an example of a display device. [Figure 17] Fig. 17A is a cross-sectional view illustrating an example of a display device, and Fig. 17B is a cross-sectional view illustrating an example of a transistor. [Figure 18] 18A to 18D are cross-sectional views showing an example of a light-emitting device. [Figure 19]19A to 19C are conceptual diagrams illustrating a light emission model of a light emitting device, and Fig. 19D is a diagram illustrating normalized luminance of a light emitting device over time. [Figure 20] 20A to 20D are diagrams illustrating the concentration of the first substance in the electron transport layer. [Figure 21] 21A and 21B are diagrams showing an example of an electronic device. [Figure 22] 22A to 22D are diagrams showing an example of an electronic device. [Diagram 23] 23A to 23F are diagrams showing an example of an electronic device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

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

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

[0028] In addition, the words "film" and "layer" can be interchanged depending on the case or situation. For example, the term "conductive layer" can be changed to the term "conductive film". Or, for example, the term "insulating film" can be changed to the term "insulating layer".

[0029] (Embodiment 1) In this embodiment, a display device and a driving method thereof according to one embodiment of the present invention will be described with reference to FIGS.

[0030] A display portion of a display device according to one embodiment of the present invention has a function of displaying an image using a light-emitting device, and further has one or both of an imaging function and a sensing function.

[0031] In a display device according to one embodiment of the present invention, a pixel has a plurality of subpixels that exhibit different colors. A subpixel that exhibits one of the colors has a light-receiving and light-emitting device instead of a light-emitting device, and a subpixel that exhibits the other colors has a light-emitting device. The light-receiving and light-emitting device has both a function of emitting light (light-emitting function) and a function of receiving light (light-receiving function). For example, when a pixel has three subpixels, that is, a red subpixel, a green subpixel, and a blue subpixel, at least one subpixel has a light-receiving and light-emitting device, and the other subpixels have a light-emitting device. Thus, a display portion of the display device according to one embodiment of the present invention has a function of displaying an image using both a light-receiving and light-emitting device and a light-emitting device.

[0032] When the light-receiving and light-emitting device serves as both a light-emitting device and a light-receiving device, a light-receiving function can be imparted to the pixel without increasing the number of subpixels included in the pixel. This makes it possible to add one or both of an imaging function and a sensing function to the display portion of the display device while maintaining the aperture ratio of the pixel (aperture ratio of each subpixel) and the resolution of the display device. Therefore, the display device of one embodiment of the present invention can have a higher aperture ratio of the pixel and can easily achieve high resolution, compared to the case where a subpixel having a light-receiving device is provided in addition to a subpixel having a light-emitting device.

[0033] In a display device according to one embodiment of the present invention, two types of data potentials (e.g., a potential of image data and a potential of correction data) can be combined to generate a potential to be supplied to a gate of a driving transistor of a light-emitting and receiving device. For example, gradation correction can be performed by combining two types of data potentials. In addition, a potential exceeding the maximum potential that can be supplied by a driving circuit (source driver circuit) that supplies the first data potential and the second data potential can be generated in a subpixel. This allows the power supply voltage of the driving circuit to be lowered, thereby reducing the power consumption of the driving circuit.

[0034] Note that in the display device of one embodiment of the present invention, a structure in which two types of data potentials are combined to generate a potential to be supplied to the gate of a driving transistor of the light-emitting device can also be applied to a subpixel having a light-emitting device.

[0035] [Pixel configuration example 1] FIG. 1 shows a circuit diagram representing one pixel of a display device.

[0036] The pixel shown in Fig. 1 has a subpixel (R·PD) that emits red light and has a light receiving function, a subpixel (G) that emits green light, and a subpixel (B) that emits blue light. The pixel shown in Fig. 1 is connected to wiring GL1, wiring GL2, wiring SE, wiring V0, wiring SLR, wiring SLG, wiring SLB, wiring WX, wiring RS, wiring TX, wiring VCP, wiring VRS, wiring VPI, wiring ANODE, and wiring CATHODE / VPD.

[0037] The sub-pixel (R·PD) that emits red light and has a light receiving function includes a transistor M1R, a transistor M2R, a transistor M3R, a transistor M4R, a transistor M11, a transistor M12, a transistor M13, a transistor M14, a capacitance C1r, a capacitance C2r, a capacitance Cf, and a light receiving / emitting device 190R·PD. The transistors M1R, M3R, M4R, M11, M12, and M14 each function as a switch.

[0038] The light emitting / receiving devices 190R·PD have a function of emitting red light and a function of receiving one or both of green and blue light. In this embodiment, an example is shown in which the sub-pixel that emits red light has an light emitting / receiving device, but the sub-pixel that emits green or blue light may have an light emitting / receiving device.

[0039] The transistor M1R has a gate electrically connected to the wiring GL1, one of the source and drain electrically connected to the wiring SLR, and the other electrically connected to the gate of the transistor M2R, one electrode of the capacitance C1r, and one electrode of the capacitance C2r. The transistor M2R has a source and drain electrically connected to one of the source and drain of the transistor M3R, one of the source and drain of the transistor M11, the other electrode of the capacitance C1r, and the anode of the light emitting and receiving device 190R·PD, and the other electrically connected to the wiring ANODE. The transistor M3R has a gate electrically connected to the wiring GL1, and the other of the source and drain electrically connected to one of the source and drain of the transistor M4R and the other electrode of the capacitance C2r. The transistor M4R has a gate electrically connected to the wiring GL2, and the other of the source and drain electrically connected to the wiring V0. The transistor M11 has a gate electrically connected to the wiring TX, and the other of its source and drain electrically connected to one of the source and drain of the transistor M12, the gate of the transistor M13, and one electrode of the capacitance Cf. The transistor M12 has a gate electrically connected to the wiring RS, and the other of its source and drain electrically connected to the wiring VRS. The transistor M13 has one of its source and drain electrically connected to one of the source and drain of the transistor M14, and the other electrically connected to the wiring VPI. The transistor M14 has a gate electrically connected to the wiring SE, and the other of its source and drain electrically connected to the wiring WX. The other electrode of the capacitance Cf is electrically connected to the wiring VCP. The cathode of the light emitting and receiving device 190R·PD is electrically connected to the wiring CATHODE / VPD.

[0040] The sub-pixel (G) that exhibits green light includes a transistor M1G, a transistor M2G, a transistor M3G, a capacitor C1g, and a light-emitting device 190G. The transistor M1G and the transistor M3G each function as a switch.

[0041] The transistor M1G has a gate electrically connected to the wiring GL1, one of its source and drain electrically connected to the wiring SLG, and the other electrically connected to the gate of the transistor M2G and one electrode of the capacitance C1g. The transistor M2G has a source and drain electrically connected to one of the source and drain of the transistor M3G, the other electrode of the capacitance C1g, and the anode of the light-emitting device 190G, and the other electrically connected to the wiring ANODE. The transistor M3G has a gate electrically connected to the wiring GL1, and the other of its source and drain electrically connected to the wiring V0. The cathode of the light-emitting device 190G is electrically connected to the wiring CATHODE / VPD.

[0042] The sub-pixel (B) that exhibits blue light includes a transistor M1B, a transistor M2B, a transistor M3B, a capacitor C1b, and a light-emitting device 190B. The transistor M1B and the transistor M3B each function as a switch.

[0043] The transistor M1B has a gate electrically connected to the wiring GL1, one of its source and drain electrically connected to the wiring SLB, and the other electrically connected to the gate of the transistor M2B and one electrode of the capacitance C1b. The transistor M2B has a source and drain electrically connected to one of the source and drain of the transistor M3B, the other electrode of the capacitance C1b, and the anode of the light-emitting device 190B, and the other electrically connected to the wiring ANODE. The transistor M3B has a gate electrically connected to the wiring GL1, and the other of its source and drain electrically connected to the wiring V0. The cathode of the light-emitting device 190B is electrically connected to the wiring CATHODE / VPD.

[0044] Selection signals for controlling the operation of the transistors are supplied to the wirings GL1, GL2, SE, TX, and RS. The selection signals each include a potential for turning the transistor on (also referred to as an on state) and a potential for turning the transistor off (also referred to as an off state).

[0045] An image signal is supplied to each of the wirings SLR, SLG, and SLB. For example, a first data potential D is supplied to the wiring SLR (see FIG. 4A).

[0046] The wiring V0 is connected to a second data potential D w and reset potential V R are provided at different times (see FIG. 4A).

[0047] A predetermined potential is supplied to the wiring VPI, the wiring VCP, the wiring VRS, the wiring ANODE, and the wiring CATHODE / VPD. A potential higher than the maximum potential applied to the gate of the transistor M13 is supplied to the wiring VPI. An arbitrary potential (for example, 0 V) ​​can be supplied to the wiring VCP. A potential lower than the wiring CATHODE / VPD is supplied to the wiring ANODE. A potential higher than the wiring CATHODE / VPD is supplied to the wiring ANODE.

[0048] The transistor M1R, the transistor M1G, the transistor M1B, the transistor M3R, the transistor M3G, and the transistor M3B are controlled by a signal supplied to the wiring GL1, and function as selection transistors for controlling the selection state of the pixel.

[0049] The transistor M2R functions as a drive transistor that controls the current flowing through the light receiving and emitting devices 190R and PD in response to the potential supplied to its gate. Similarly, the transistors M2G and M2B function as drive transistors that control the current flowing through the light emitting devices 190G and 190B in response to the potential supplied to their gates.

[0050] The transistor M1R functions as a switch that controls conduction / non-conduction between the wiring SLR and the gate of the transistor M2R. When the transistor M1R is in a conductive state, a first data potential D supplied to the wiring SLR is supplied to the gate of the transistor M2R.

[0051] When the transistor M1R is in a conductive state, the transistor M3R is also in a conductive state at the same time. The transistor M3R functions as a switch for supplying a reset potential to the anodes of the light emitting and receiving devices 190R and PD. When the transistors M1R and M3R are in a conductive state, the transistor M4R is also made conductive at the same time. At this time, a reset potential is supplied to the wiring V0. This makes it possible to supply a reset potential to the anodes of the light emitting and receiving devices 190R and PD.

[0052] By supplying the first data potential D and the reset potential during the same period, the voltage between the gate and source of the transistor M2R can be determined regardless of the electrical characteristics of the light emitting / receiving device 190R·PD, thereby improving the display quality of the display device.

[0053] One electrode of the capacitor C2r is electrically connected to the gate of the transistor M2R. The transistor M4R functions as a switch that controls conduction / non-conduction between the other electrode of the capacitor C2r and the wiring V0. When the second data potential is supplied to the wiring V0, the transistors M1R and M3R are brought into a non-conducting state, and the transistor M4R is brought into a conducting state. By bringing the transistor M4R into a conducting state, the second data potential can be supplied to the other electrode of the capacitor C2r via the transistor M4R.

[0054] After supplying the first data potential to the gate of transistor M2R, transistor M1R is turned off to put the gate of transistor M2R into a floating state, and a second data potential is supplied to the other electrode of capacitor C2r via transistor M4R. The potential of the gate of transistor M2R (potential of node GR) changes from the first data potential in response to the second data potential due to capacitive coupling via capacitor C2r. The light emitting and receiving device 190R·PD can emit light with a brightness corresponding to the potential of node GR.

[0055] The wiring V0 can serve as both the wiring for supplying the second data potential and the wiring for supplying the reset potential. Therefore, even in a multi-function display device, the number of wirings can be reduced, and high definition can be achieved.

[0056] Furthermore, the wiring V0 may be a wiring that supplies the second data potential and the reset potential to two or more subpixels, which is preferable because the number of wirings included in the display device can be further reduced.

[0057] When the transistor M1G is in a conductive state, the transistor M3G is also in a conductive state at the same time, the potential supplied to the wiring SLG is supplied to the gate of the transistor M2G, and the reset potential supplied to the wiring V0 is supplied to the source or drain of the transistor M3G. The light-emitting device 190G can emit light with a brightness corresponding to the gate potential of the transistor M2G. In addition, when the transistor M1B is in a conductive state, the transistor M3B is also in a conductive state at the same time, the potential supplied to the wiring SLB is supplied to the gate of the transistor M2B, and the reset potential supplied to the wiring V0 is supplied to the source or drain of the transistor M3B. The light-emitting device 190B can emit light with a brightness corresponding to the gate potential of the transistor M2B.

[0058] The transistor M11 is controlled by a signal supplied to the line TX, and has a function of controlling the timing at which the potential of the node FD changes in response to the current flowing through the light receiving and emitting devices 190R and PD. The transistor M12 is controlled by a signal supplied to the line RS, and has a function of resetting the potential of the node FD by setting the potential of the node FD connected to the gate of the transistor M13 to the potential supplied to the line VRS. The transistor M13 functions as an amplifying transistor that outputs according to the potential of the node FD. The transistor M14 is controlled by a signal supplied to the line SE, and functions as a selection transistor for reading out the output according to the potential of the node FD to an external circuit connected to the line WX.

[0059] In the display device of one embodiment of the present invention, it is preferable to use a transistor having a metal oxide (also referred to as an oxide semiconductor) in a semiconductor layer in which a channel is formed (hereinafter also referred to as an OS transistor) for all of the transistors included in the pixel shown in Fig. 1. The off-state current of an OS transistor is extremely small and charge accumulated in a capacitor connected in series to the transistor can be held for a long period of time. Furthermore, the use of an OS transistor can reduce power consumption of the display device.

[0060] Alternatively, in the display device of one embodiment of the present invention, it is preferable to use a transistor having silicon in a semiconductor layer in which a channel is formed (hereinafter also referred to as a Si transistor) for all the transistors included in the pixel shown in FIG. Examples of silicon include single crystal silicon, polycrystalline silicon, amorphous silicon, and the like. In particular, it is preferable to use a transistor having low temperature polysilicon (LTPS) in a semiconductor layer (hereinafter also referred to as an LTPS transistor). An LTPS transistor has high field-effect mobility and can operate at high speed.

[0061] Furthermore, by using Si transistors such as LTPS transistors, it becomes easier to fabricate various circuits consisting of CMOS circuits on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0062] Alternatively, in the display device according to one embodiment of the present invention, it is preferable to use two types of transistors in the subpixel (R·PD) having a light-receiving and light-emitting device. Specifically, it is preferable for the subpixel to have an OS transistor and an LTPS transistor. By changing the material of the semiconductor layer depending on the function required of the transistor, it is possible to improve the quality of the pixel circuit of the subpixel (R·PD) having a light-receiving and light-emitting device and to improve the accuracy of sensing and imaging. In this case, the subpixel (G) and the subpixel (B) having a light-emitting device may use either an OS transistor or an LTPS transistor, or both.

[0063] Furthermore, even when two types of transistors (for example, OS transistors and LTPS transistors) are used in a pixel, the use of LTPS transistors makes it easy to fabricate various circuits consisting of CMOS circuits on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0064] A transistor using a metal oxide having a wider band gap and a lower carrier density than silicon can realize an extremely small off-current. Therefore, the small off-current allows the charge stored in the capacitor connected in series with the transistor to be held for a long period of time. Therefore, it is preferable to use OS transistors for the transistors M1R, M1G, M1B, M3R, M3G, M3B, M4R, M11, and M12 connected in series with the capacitors C1r, C1g, C1b, C2r, and Cf.

[0065] Moreover, it is preferable to use a Si transistor for the transistor M13, which allows the image data to be read out at high speed.

[0066] Although the transistors are shown as n-channel transistors in FIG. 1, p-channel transistors can also be used.

[0067] Although FIG. 1 shows an example in which each transistor has one gate, at least one of the multiple transistors included in the subpixel may have a back gate. A pair of gates of the transistor may be electrically connected to each other. This can increase the on-state current of the transistor and improve the saturation characteristics, thereby realizing a display device with higher reliability. Alternatively, the back gate may be electrically connected to a wiring to which a constant potential is applied. This can stabilize the electrical characteristics of the transistor. Alternatively, the back gate may be electrically connected to a wiring to which a potential for controlling a threshold voltage of the transistor is applied.

[0068] It is preferable to provide one or more layers having transistors and / or capacitances at positions overlapping the light receiving and emitting devices 190R and PD, the light emitting device 190G, or the light emitting device 190B, thereby making it possible to reduce the effective area occupied by each pixel circuit and realize a high-definition display unit.

[0069] [Pixel configuration example 2] FIG. 2 shows a circuit diagram representing one pixel of the display device.

[0070] The subpixel (G) that emits green light shown in Figure 2 differs from the subpixel (G) shown in Figure 1 in that it has a transistor M4G and a capacitor C2g. Similarly, the subpixel (B) that emits blue light shown in Figure 2 differs from the subpixel (B) shown in Figure 1 in that it has a transistor M4B and a capacitor C2b. Note that the subpixel (R·PD) that emits red light and has a light receiving function shown in Figure 2 is similar to the subpixel (R·PD) shown in Figure 1.

[0071] 2, the other of the source and drain of the transistor M3G is electrically connected to one of the source and drain of the transistor M4G and the other electrode of the capacitor C2g, not to the wiring V0. The gate of the transistor M4G is electrically connected to the wiring GL2, and the other of the source and drain is electrically connected to the wiring V0. One electrode of the capacitor C2g is electrically connected to the other of the source and drain of the transistor M1G, the gate of the transistor M2G, and one electrode of the capacitor C1g.

[0072] 2, the other of the source and drain of the transistor M3B is electrically connected to one of the source and drain of the transistor M4B and the other electrode of the capacitor C2b, not to the wiring V0. The gate of the transistor M4B is electrically connected to the wiring GL2, and the other of the source and drain is electrically connected to the wiring V0. One electrode of the capacitor C2b is electrically connected to the other of the source and drain of the transistor M1B, the gate of the transistor M2B, and one electrode of the capacitor C1b.

[0073] With this configuration, in the subpixel (G) and the subpixel (B), the data potential supplied from the wiring SLG or the wiring SLB and the data potential supplied from the wiring V0 can be combined to generate a potential to be supplied to the gate of the driving transistor (transistor M2G, M2B) of the light-emitting device. Therefore, it is possible to perform gradation correction and to apply a voltage equal to or higher than the output voltage of the source driver as the gate voltage of the driving transistor.

[0074] [Display device driving method] Figures 3A and 3B show an example of a method for driving a display device, and Figures 4A, 4B, and 5A to 5D show timing charts of each operation.

[0075] As shown in Fig. 3A, when an image is displayed, an image signal is written for each row. As shown in Fig. 3A, writing is performed in the order of the first row, the second row, etc. Fig. 4A shows a timing chart of the image signal writing operation P1 for the pixels in the nth row shown in Fig. 3A.

[0076] In the following, a subpixel (R·PD) that emits red light and has a light receiving function, as shown in FIG. 1 and FIG. 2, will be described as an example. <n>, nth row wiring GL2 <n>13 also shows an example of the transition of signals input to the wirings SLR and V0 and the potential of the node GR.

[0077] It should be noted that image signals can be written in the same manner to the sub-pixel (G) that exhibits green light and the sub-pixel (B) that exhibits blue light, as shown in FIG.

[0078] In the following, for ease of explanation, the influences of the threshold voltage of a transistor, the resistance of a transistor in an on-state, the gate capacitance of a transistor, wiring resistance, parasitic capacitance, and the like are not taken into consideration.

[0079] Before time T0, wiring GL1 <n>, wiring GL2 <n>A potential (here, a low-level potential) that turns off the transistor is applied to the wiring SLR and the wiring V0. Data to be written to the pixels in the previous row is applied to the wiring SLR and the wiring V0. The node GR is connected to the potential V X is a given state.

[0080] At time T0, wiring GL1 <n>and wiring GL2 <n>A potential (here, a high-level potential) is applied to make the transistor conductive, a data potential D is applied to the wiring SLR, and a reset potential V R is given.

[0081] In the period T0-T1, the transistors M1R, M3R, and M4R are in a conductive state. The other electrode of the capacitor C2r is supplied with a reset potential V R Furthermore, a reset potential V R A data potential D is supplied to the node GR via the transistor M1R.

[0082] In this way, when writing the data potential D to the node GR, a reset potential V R By writing the reset potential V, the potential difference between the node SA and the node GR, i.e., the gate-source voltage of the transistor M2R, can be determined regardless of the electrical state of the light receiving and emitting devices 190R and PD. Specifically, the gate-source voltage of the transistor M2R is set to the reset potential V R Based on this, DV R It becomes.

[0083] The capacitance C2r is connected between the data potential D and the reset potential V R The charge state depends on the potential difference.

[0084] At this time, the anode of the light-receiving device 190R·PD is supplied with a reset potential V R The reset potential V R By setting the above, the light receiving and emitting device 190R·PD does not emit light.

[0085] Next, at time T1, the wiring GL1 <n>A low level potential is applied to the wiring GL2 <n>A high-level potential is applied to the line V0, and a data potential D W is given.

[0086] When the wiring GL1 is at a low potential, the transistors M1R and M3R are turned off, and the node GR is brought into a floating state.

[0087] The other electrode of the capacitor C2r is connected to a data potential D W The capacitance C2r is supplied with a voltage DV R is in a charged state, the potential of the other electrode is reset potential V R Data potential D W As a result, the potential of the node GR changes from potential D to potential V D+W Here, the change in the potential of the node GR (i.e., the potential V D+W The difference between the data potential D and the potential D is roughly determined by the capacitance value of the capacitance C2r and the capacitance value of the capacitance C1r. When the capacitance value of the capacitance C2r is sufficiently larger than the capacitance value of the capacitance C1r, the change in the potential of the node GR is W and the reset potential V R The value is close to the difference between

[0088] This causes the gate of transistor M2R to be connected to the potential V D+W A current according to this potential flows through the light emitting and receiving devices 190R and PD via the transistor M2R, thereby causing the light emitting and receiving devices 190R and PD to emit light.

[0089] For example, the data potential D W By supplying a high-level potential as the data potential D W By supplying a low-level potential as the luminance level, the luminescence brightness of the light receiving and emitting devices 190R and PD can be reduced.

[0090] This driving method allows the light emission luminance to be adjusted for each sub-pixel, thereby realizing so-called pixel dimming. By correcting the luminance to an optimum level according to the image to be displayed, a display with high display quality can be realized. In addition, since data for display and data for correction can be supplied to the pixels individually, it is not necessary to generate video data that is a combination of data for display and data for correction. This allows the configuration of the driving circuit, etc. to be simplified.

[0091] At time T2, wiring GL2 <n>A low-level potential is applied to the n-th row pixel. This completes the data writing operation to the sub-pixel (R·PD) that emits red light and has a light receiving function in the n-th row pixel. After time T2, the data writing operation moves to the next row.

[0092] Figure 3B shows the sequence for capturing an image using the global shutter method with the light receiving and emitting device 190R·PD. As shown in Figure 3B, when capturing an image using the light receiving and emitting device 190R·PD, first, a write operation of an image signal for capturing an image is performed for each row, then, while retaining the written data, an initialization (reset) operation, an exposure (accumulation) operation, and a transfer operation are performed in that order in the sub-pixels having a light receiving function, and then the image data is read out for each row to perform detection.

[0093] 4B shows a timing chart of a write operation P2 of an image signal for imaging in the pixels in the nth row. Here, an example is shown in which the light emitting device 190G is used as a light source in the pixel circuit shown in FIG. 1, and imaging is performed by the light emitting and receiving devices 190R and PD.

[0094] First, before time T3, wiring GL1 <n>potential and wiring GL2 <n>The potential of the wiring TX and wiring RS is set to a high level potential. <n>, and wiring SE <n>As a result, the transistors M1R, M3R, and M4R are turned on, and the potential Vb of the wiring SLR and the reset potential V R potential difference (voltage Vb-V R ) is stored in the capacitors C1r and C2r. In addition, the transistors M1G and M3G are turned on, and the potential Vem of the wiring SLG and the reset potential V R potential difference (voltage Vem-V R ) is stored in the capacitor C1g. Furthermore, the transistors M1B and M3B are turned on, and the potential Vb of the wiring SLB and the reset potential V R potential difference (voltage Vb-V R At this time, a charge corresponding to the line WX <m>The potential is a low-level potential.

[0095] Here, the potential Vb of the wiring SLR is such that the gate-source voltage (Vgs) and the threshold voltage (Vth) in the transistor M2R satisfy Vgs = Vb - V R < is a potential that satisfies <Vth. Thereby, the transistor M2R can be completely turned off.

[0096] The potential Vem of the wiring SLG is a potential for causing the light-emitting device 190G to emit light. As the potential Vem, it is preferable to supply a potential at which the light emission of the light-emitting device 190G has sufficient luminance for imaging.

[0097] To the wiring SLB, a potential at which the light-emitting device 190B does not emit light is supplied. In FIG. 4B, an example in which the potential Vb is supplied to the wiring SLB is shown, but it is not limited thereto. The potential supplied to the wiring SLB may be the same as or different from the potential supplied to the wiring SLR. Note that when the light-emitting device 190B is also used as a light source during imaging, a potential for causing the light-emitting device 190B to emit light is supplied to the wiring SLB.

[0098] Next, between time T3 and time T4, the wiring GL1 <n>potential and wiring GL2 <n>By setting the potential of the transistor M2G to a low level potential, the transistors M1R, M1G, M1B, M3R, M3G, M3B, and M4R become non-conductive, the charges stored in the capacitors C1r, C1g, C1b, and C2r are held, and the writing operation of the image signal for imaging is completed. The light-emitting device 190G emits light based on the gate potential of the transistor M2G.

[0099] FIG. 5A shows a timing chart of the initialization (reset) operation P3.

[0100] At time T5, the wiring TX and the wiring RS <n>By setting the potential of the wiring VRS to a high level potential, the transistors M11 and M12 become conductive. As a result, the potential of the anode of the light-receiving and light-emitting device 190R·PD and the potential of the node FD can be set to the potential supplied to the wiring VRS, and the potential of the node FD can be reset. Since the node GR is in a floating state, Vgs is preserved, and the transistor M2R remains off regardless of the potential of the node SA. By supplying a potential lower than that of the wiring CATHODE / VPD to the wiring VRS, a reverse bias can be applied to the light-receiving and light-emitting device 190R·PD.

[0101] At time T6, the wiring TX and the wiring RS <n>By setting the potential of the transistor M11 and the transistor M12 to a low-level potential, the initialization operation is completed.

[0102] FIG. 5B shows a timing chart of the exposure (accumulation) operation P4.

[0103] Between time T7 and time T8, the light receiving and emitting devices 190R and PD generate electric charges by receiving light emitted by the light emitting device 190G. As a result, electric charges are accumulated in the capacitance of the light receiving and emitting devices 190R and PD, and the potential of the node SA becomes a potential according to the electric charges generated in the light receiving and emitting devices 190R and PD.

[0104] In addition, between time T7 and time T8, the wiring SLR, the wiring SLG, the wiring SLB, and the wiring GL1 <n>, wiring GL2 <n>, wiring TX, wiring RS <n>, Wiring SE <n>, and wiring WX <m>can be a low level potential.

[0105] FIG. 5C shows a timing chart of the transfer operation P5.

[0106] At time T9, the potential of the line TX is set to a high level potential, which turns on the transistor M11. This causes charge to be transferred from the node SA to the node FD. In other words, the potential of the node FD becomes a potential that corresponds to the charge generated in the light receiving and emitting devices 190R and PD.

[0107] At time T10, the potential of the wiring TX is set to a low-level potential, so that the transistor M11 is turned off and the transfer operation ends.

[0108] FIG. 5D shows a timing chart of the sensing operation P6.

[0109] At time T11, wiring SE <n>By setting the potential of the line WX <m>The potential of the wiring WX can be set to a potential corresponding to the charge generated in the light receiving and emitting device 190R / PD. <m>The signal can be read out by an external circuit connected to the transistor M13. The transistor M13 can also be considered as a transistor included in a source follower circuit.

[0110] At time T12, wiring SE <n>The potential of the wiring RS remains high. <n>By setting the potential of the line WX <m>to a potential corresponding to the potential of the wiring VRS. This allows the background potential to be read out. Therefore, in the external circuit, fixed pattern noise caused by the transistor M13 can be removed from the output signal read out at time T11. This allows the effect of variations in the characteristics of the transistor M13 between pixels to be reduced.

[0111] At time T13, wiring RS <n>By setting the potential at the input terminal M11 to a low level potential, the transistor M12 is rendered non-conductive.

[0112] At time T14, wiring SE <n>By setting the potential at the input terminal of the transistor M14 to a low level potential, the transistor M14 becomes non-conductive, and the detection operation ends.

[0113] By repeating the operation from time T3 to time T14, imaging can be repeated. Furthermore, when OS transistors are used for the transistors M1R, M2R, M1G, M2G, M1B, and M2B, it is possible to hold an imaging image signal for a long time, so that the frequency of performing the write operation P2 of the imaging image signal can be reduced. Therefore, after performing the operation from time T3 to time T14 once, the operation from time T5 to time T14 may be repeated a predetermined number of times, and then the operation at time T3 may be resumed.

[0114] The display device of the present embodiment can be driven in any of an image display mode, an image capture mode, and a simultaneous image display and image capture mode. In the image display mode, for example, a full-color image can be displayed. In the image capture mode, for example, an image for image capture (for example, monochromatic green or monochromatic blue) can be displayed, and an image can be captured using a light receiving and emitting device. In the image capture mode, for example, fingerprint authentication can be performed. In the simultaneous image display and image capture mode, for example, some pixels can display an image for image capture using a light emitting device (light emitting device 190G or light emitting device 190B), capture an image using the light receiving and emitting devices 190R and PD, and a full-color image can be displayed using the light receiving and emitting devices and light emitting devices of the remaining pixels.

[0115] As described above, in the display device of this embodiment, the sub-pixel (R·PD) that emits red light and has a light receiving function can be used for both image display and light detection. Also, some of the multiple sub-pixels (R·PD) can be used for image display and the rest for light detection. This allows the display device of this embodiment to be driven in any of a mode for image display, a mode for capturing images, and a mode for simultaneously displaying and capturing images.

[0116] Furthermore, in the display device of the present embodiment, two types of data potentials (for example, a potential of image data and a potential of correction data) can be combined to generate a potential to be supplied to the gate of the driving transistor of the light emitting / receiving device. Therefore, gradation correction can be performed when the light emitting / receiving device is caused to emit light. Furthermore, a voltage equal to or higher than the output voltage of the source driver can be applied as the gate voltage of the driving transistor, so that the power consumption of the source driver can be reduced.

[0117] This embodiment mode can be combined with other embodiment modes as appropriate. In addition, in the case where a plurality of configuration examples are shown in one embodiment mode in this specification, the configuration examples can be combined as appropriate.

[0118] (Embodiment 2) In this embodiment, a display device according to one embodiment of the present invention will be described with reference to FIGS.

[0119] A display device according to one embodiment of the present invention includes a light-emitting device and a light-receiving and light-emitting device.

[0120] A light-receiving and light-emitting device can be fabricated by combining an organic EL device, which is a light-emitting device, with an organic photodiode, which is a light-receiving device. For example, a light-receiving and light-emitting device can be fabricated by adding an active layer of an organic photodiode to the layered structure of an organic EL device. Furthermore, a light-receiving and light-emitting device fabricated by combining an organic EL device and an organic photodiode can suppress an increase in the number of film formation steps by forming layers that can be in common with the organic EL device in a single step.

[0121] For example, one of the pair of electrodes (common electrode) can be a layer common to the light receiving / emitting device and the light emitting device. In addition, 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 layer common to the light receiving / emitting device and the light emitting device. In addition, the light receiving / emitting device and the light emitting device can have the same configuration, except for the presence or absence of the active layer of the light receiving device. In other words, the light receiving / emitting device can be manufactured by simply adding the active layer of the light receiving device to the light emitting device. In this way, by having the light receiving / emitting device and the light emitting device have a common layer, the number of film formations and the number of masks can be reduced, and the manufacturing process and manufacturing cost of the display device can be reduced. In addition, a display device having a light receiving / emitting device can be manufactured by using an existing manufacturing apparatus and manufacturing method for a display device.

[0122] In addition, the layers of the light-receiving and light-emitting device may have different functions when the light-receiving and light-emitting device functions as a light-receiving device and when the light-receiving and light-emitting device functions as a light-emitting device. In this specification, components are named based on their functions when the light-receiving and light-emitting device functions as a light-emitting device. For example, a hole injection layer functions as a hole injection layer when the light-receiving and light-emitting device functions as a light-emitting device, and functions as a hole transport layer when the light-receiving and light-emitting device functions as a light-receiving device. Similarly, an electron injection layer functions as an electron injection layer when the light-receiving and light-emitting device functions as a light-emitting device, and functions as an electron transport layer when the light-receiving and light-emitting device functions as a light-receiving device.

[0123] In this manner, the display device of this embodiment has a light-receiving and light-emitting device in a display portion. Specifically, the light-receiving and light-emitting devices are arranged in a matrix in the display portion. Therefore, the display portion has one or both of an imaging function and a sensing function in addition to a function of displaying an image.

[0124] The display unit can be used as an image sensor or a touch sensor. That is, by detecting light with the display unit, it is possible to capture an image or detect the proximity or contact of an object (such as a finger or a pen). Furthermore, the display device of this embodiment can use the light-emitting device as a light source for the sensor. Therefore, it is not necessary to provide a light-receiving unit and a light source separately from the display device, and the number of components of the electronic device can be reduced.

[0125] In the display device of this embodiment, when an object reflects the light emitted by the light-emitting device included in the display unit, the light-receiving device can detect the reflected light, making it possible to capture images and detect touch (contact or proximity) even in dark places.

[0126] The display device of this embodiment has a function of displaying an image using a light-emitting device and a light-receiving and light-emitting device, that is, the light-emitting device and the light-receiving and light-emitting device function as display devices (also referred to as display elements).

[0127] As the light-emitting device, it is preferable to use an EL device such as an OLED (Organic Light Emitting Diode) or a QLED (Quantum-dot Light Emitting Diode). Examples of light-emitting substances that the EL device has include substances that emit fluorescence (fluorescent materials), substances that emit phosphorescence (phosphorescent materials), inorganic compounds (quantum dot materials, etc.), and substances that exhibit thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) materials). Also, LEDs such as micro LEDs (Light Emitting Diodes) can be used as the light-emitting device.

[0128] The display device of this embodiment has a function of detecting light using a light-receiving and light-emitting device that can detect light having a shorter wavelength than light emitted by the light-receiving and light-emitting device itself.

[0129] When the light emitting and receiving device is used as an image sensor, the display device of this embodiment can capture an image using the light emitting and receiving device. For example, the display device of this embodiment can be used as a scanner.

[0130] For example, data such as fingerprints and palm prints can be acquired using an image sensor. That is, a biometric authentication sensor can be built into the display device of the present embodiment. By building a biometric authentication sensor into the display device, the number of components in the electronic device can be reduced, and the electronic device can be made smaller and lighter, compared to a case where a biometric authentication sensor is provided separately from the display device.

[0131] In addition, data such as the user's facial expression, eye movement, or change in pupil diameter can be obtained using an image sensor. By analyzing the data, the user's mental and physical information can be obtained. By changing the display and / or audio output content based on the information, it is possible to ensure that the user can use the device safely, for example, in a VR (Virtual Reality) device, an AR (Augmented Reality) device, or an MR (Mixed Reality) device.

[0132] Furthermore, when the light emitting and receiving device is used as a touch sensor, the display device of the present embodiment can detect the proximity or contact of an object by using the light emitting and receiving device.

[0133] The light emitting / receiving device functions as a photoelectric conversion device that detects light incident on the light emitting / receiving device and generates electric charges. The amount of electric charges generated is determined based on the amount of light incident on the device.

[0134] A light receiving and emitting device can be fabricated by adding an active layer of a light receiving device to the above-mentioned light emitting device structure.

[0135] For example, the active layer of a pn-type or pin-type photodiode can be used for the light receiving / emitting device.

[0136] In particular, it is preferable to use an active layer of an organic photodiode having a layer containing an organic compound for the light receiving and emitting device. Organic photodiodes can be easily made thin, lightweight, and large in area, and have a high degree of freedom in shape and design, making them applicable to a variety of display devices.

[0137] 6A to 6D each show a cross-sectional view of a display device according to one embodiment of the present invention.

[0138] A display device 50A shown in FIG. 6A has, between a substrate 51 and a substrate 59, a layer 53 having light-receiving and light-emitting devices, and a layer 57 having light-emitting devices.

[0139] A display device 50B shown in FIG. 6B includes, between a substrate 51 and a substrate 59, a layer 53 having light-receiving and light-emitting devices, a layer 55 having transistors, and a layer 57 having light-emitting devices.

[0140] The display device 50A and the display device 50B are configured such that green (G) light and blue (B) light are emitted from the layer 57 having the light-emitting devices, and red (R) light is emitted from the layer 53 having the light-receiving and light-emitting devices. Note that in the display device according to one embodiment of the present invention, the color of the light emitted from the layer 53 having the light-receiving and light-emitting devices is not limited to red.

[0141] The light emitting and receiving devices included in the layer 53 having the light emitting and receiving devices can detect light incident from the outside of the display device 50A or the display device 50B. The light emitting and receiving devices can detect, for example, one or both of green (G) light and blue (B) light.

[0142] A display device according to an embodiment of the present invention has a plurality of pixels arranged in a matrix. Each pixel has one or more sub-pixels. Each sub-pixel has one light-receiving / emitting device or one light-emitting device. For example, a pixel may have three sub-pixels (three colors: R, G, and B, or three colors: yellow (Y), cyan (C), and magenta (M)) or four sub-pixels (four colors: R, G, B, and white (W), or four colors: R, G, B, and Y). At least one sub-pixel of one color has a light-receiving / emitting device. The light-receiving / emitting device may be provided in all pixels or in some pixels. Also, one pixel may have multiple light-receiving / emitting devices.

[0143] The layer 55 having transistors includes, for example, a transistor electrically connected to a light receiving / emitting device and a transistor electrically connected to a light emitting device. The layer 55 having transistors may further include wiring, electrodes, terminals, capacitance, resistance, and the like.

[0144] The display device according to one embodiment of the present invention may have a function of detecting an object such as a finger in contact with the display device (FIG. 6C). Alternatively, the display device may have a function of detecting an object in proximity (not in contact) with the display device (FIG. 6D). For example, as shown in FIGS. 6C and 6D, light emitted by a light-emitting device in layer 57 having a light-emitting device is reflected by finger 52 in contact with or in proximity to display device 50B, and the light-receiving and light-emitting device in layer 53 having a light-receiving and light-emitting device detects the reflected light. This makes it possible to detect that finger 52 is in contact with or in proximity to display device 50B.

[0145] [Pixels] 6E to 6G and 7A to 7D show examples of pixels. Note that the arrangement of the sub-pixels is not limited to the order shown in the drawings. For example, the positions of the sub-pixels (B) and (G) may be reversed.

[0146] The pixel shown in Fig. 6E has a stripe arrangement and includes a subpixel (R PD) that emits red light and has a light-receiving function, a subpixel (G) that emits green light, and a subpixel (B) that emits blue light. In a display device in which a pixel is composed of three subpixels, R, G, and B, a light-emitting device used for the R subpixel can be replaced with a light-receiving / light-emitting device to fabricate a display device in which the pixel has a light-receiving function.

[0147] The pixel shown in Fig. 6F is arranged in a matrix and has a subpixel (R PD) that emits red light and has a light-receiving function, a subpixel (G) that emits green light, a subpixel (B) that emits blue light, and a subpixel (W) that emits white light. Even in a display device in which a pixel is composed of four subpixels, R, G, B, and W, it is possible to fabricate a display device in which the pixel has a light-receiving function by replacing the light-emitting device used in the R subpixel with a light-receiving / light-emitting device.

[0148] The pixel shown in FIG. 6G is arranged in a Pentile array and has sub-pixels that emit two colors of light, with the combinations differing depending on the pixel. The upper left pixel and lower right pixel shown in FIG. 6G have a sub-pixel (R PD) that emits red light and has a light receiving function, and a sub-pixel (G) that emits green light. The lower left pixel and upper right pixel shown in FIG. 6G have a sub-pixel (G) that emits green light, and a sub-pixel (B) that emits blue light. Note that the shape of the sub-pixels shown in FIG. 6G indicates the top shape of the light-emitting device or light-receiving / light-emitting device that the sub-pixels have.

[0149] The pixel shown in Fig. 7A has a subpixel (R·PD) that emits red light and has a light receiving function, a subpixel (G) that emits green light, and a subpixel (B) that emits blue light. The subpixel (R·PD) is arranged in a column different from the subpixels (G) and (B). The subpixels (G) and (B) are arranged alternately in the same column, with one provided in an odd-numbered row and the other provided in an even-numbered row. Note that the subpixels arranged in a column different from the subpixels of other colors are not limited to red (R) and may be green (G) or blue (B).

[0150] FIG. 7B shows two pixels, each of which is made up of three subpixels surrounded by dotted lines. The pixel shown in FIG. 7B has a subpixel (R·PD) that emits red light and has a light receiving function, a subpixel (G) that emits green light, and a subpixel (B) that emits blue light. In the left pixel shown in FIG. 7B, the subpixel (G) is arranged in the same row as the subpixel (R·PD), and the subpixel (B) is arranged in the same column as the subpixel (R·PD). In the right pixel shown in FIG. 7B, the subpixel (G) is arranged in the same row as the subpixel (R·PD), and the subpixel (B) is arranged in the same column as the subpixel (G). In the pixel layout shown in FIG. 7B, the subpixels (R·PD), (G), and (B) are arranged repeatedly in both odd and even rows, and in each column, subpixels of different colors are arranged in the odd and even rows.

[0151] Figure 7C is a modified example of the pixel array shown in Figure 6G. The upper left pixel and lower right pixel shown in Figure 7C have a sub-pixel (R·PD) that emits red light and has a light receiving function, and a sub-pixel (G) that emits green light. The lower left pixel and upper right pixel shown in Figure 7C have a sub-pixel (R·PD) that emits red light and has a light receiving function, and a sub-pixel (B) that emits blue light.

[0152] In FIG. 6G, each pixel is provided with a sub-pixel (G) that emits green light. On the other hand, in FIG. 7C, each pixel is provided with a sub-pixel (R·PD) that emits red light and has a light receiving function. Since each pixel is provided with a sub-pixel that has a light receiving function, the configuration shown in FIG. 7C can capture images with higher resolution than the configuration shown in FIG. 6G. This can improve the accuracy of biometric authentication, for example.

[0153] The top surface shapes of the light-emitting device and the light-receiving / light-emitting device are not particularly limited and may be a circle, an ellipse, a polygon, a polygon with rounded corners, etc. With respect to the top surface shape of the light-emitting device of the subpixel (G), Fig. 6G shows an example in which it is a circle, and Fig. 7C shows an example in which it is a square. The top surface shapes of the light-emitting device and the light-receiving / light-emitting device of each color may be different from each other, or may be the same for some or all of the colors.

[0154] 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 of the colors. For example, the aperture ratio of the sub-pixel (G in FIG. 6G, sub-pixel (R·PD) in FIG. 7C) provided in each pixel may be smaller than the aperture ratios of the sub-pixels of the other colors.

[0155] Fig. 7D is a modified example of the pixel array shown in Fig. 7C. Specifically, the configuration of Fig. 7D is obtained by rotating the configuration of Fig. 7C by 45°. Although Fig. 7C has been described as one pixel being composed of two sub-pixels, it can also be considered as one pixel being composed of four sub-pixels as shown in Fig. 7D.

[0156] In FIG. 7D, a description will be given assuming that one pixel is composed of four sub-pixels surrounded by dotted lines. One pixel has two sub-pixels (R PD), one sub-pixel (G), and one sub-pixel (B). In this way, one pixel has multiple sub-pixels with a light receiving function, so that imaging can be performed with high resolution. This can improve the accuracy of biometric authentication. For example, the resolution of the imaging can be set to the root double of the resolution of the display.

[0157] A display device to which the configuration shown in FIG. 7C or 7D is applied has p (p is an integer of 2 or more) first light-emitting devices, q (q is an integer of 2 or more) second light-emitting devices, and r (r is an integer greater than p and greater than q) light-receiving and light-emitting devices. p and r satisfy r=2p. Furthermore, p, q, and r satisfy r=p+q. One of the first light-emitting devices and the second light-emitting devices emits green light, and the other emits blue light. The light-receiving and light-emitting device emits red light and has a light-receiving function.

[0158] For example, when a light-emitting / receiving device is used to perform touch detection, it is preferable that light emitted from the light source is difficult for a user to see. Since blue light is less visible than green light, it is preferable to use a light-emitting device that emits blue light as the light source. Therefore, it is preferable that the light-emitting / receiving device has a function of receiving blue light.

[0159] As described above, pixels with various arrangements can be applied to the display device of one embodiment of the present invention.

[0160] In the display device of this embodiment, since there is no need to change the pixel arrangement in order to incorporate a light-receiving function into the pixel, it is possible to add an imaging function and / or a sensing function to the display portion without reducing the aperture ratio and the resolution.

[0161] [Light receiving and emitting devices] 8A to 8E show examples of the layered structure of the light emitting and receiving device.

[0162] The light emitting and receiving device has at least an active layer and a light emitting layer between a pair of electrodes.

[0163] The light-receiving and light-emitting device may further include a layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a substance with high hole-blocking properties, a substance with high electron-transport properties, a substance with high electron-injection properties, a substance with high electron-blocking properties, a bipolar substance (a substance with high electron-transport properties and high hole-transport properties), or the like, in addition to the active layer and the light-emitting layer.

[0164] Each of the light emitting and receiving devices shown in FIGS. 8A to 8C includes 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.

[0165] 8A to 8C can be considered to have a configuration in which an active layer 183 is added to a light-emitting device. Therefore, the light-emitting and receiving device can be formed in parallel with the formation of the light-emitting device by simply adding a process of forming the active layer 183 to the manufacturing process of the light-emitting device. In addition, the light-emitting device and the light-emitting and receiving device can be formed on the same substrate. Therefore, it is possible to provide the display section with one or both of an imaging function and a sensing function without significantly increasing the number of manufacturing processes.

[0166] The stacking order of the light emitting layer 193 and the active layer 183 is not limited. Fig. 8A shows an example in which the active layer 183 is provided on the hole transport layer 182, and the light emitting layer 193 is provided on the active layer 183. Fig. 8B shows an example in which the light emitting layer 193 is provided on the hole transport layer 182, and the active layer 183 is provided on the light emitting layer 193. The active layer 183 and the light emitting layer 193 may be in contact with each other as shown in Figs. 8A and 8B.

[0167] As shown in Fig. 8C, 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 selected from a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a hole blocking layer, an electron blocking layer, and the like can be used. Alternatively, as the buffer layer, a layer containing a bipolar material may be used. Fig. 8C shows an example in which a hole transport layer 182 is used as the buffer layer.

[0168] By providing a buffer layer between the active layer 183 and the light emitting layer 193, it is possible to suppress the transfer of excitation energy from the light emitting layer 193 to the active layer 183. In addition, the buffer layer can be used to adjust the optical path length (cavity length) of the microresonator (microcavity) structure. Therefore, a light emitting / receiving device having a buffer layer between the active layer 183 and the light emitting layer 193 can obtain high light emission efficiency.

[0169] 8A and 8C in that it does not have a hole transport layer 182. The light emitting and receiving device may not have at least one layer among the hole injection layer 181, the hole transport layer 182, the electron transport layer 184, and the electron injection layer 185. The light emitting and receiving device may also have other functional layers, such as a hole blocking layer or an electron blocking layer.

[0170] The light emitting and receiving device shown in FIG. 8E differs from the light emitting and receiving devices shown in FIGS. 8A to 8C in that it does not have the active layer 183 and the light emitting layer 193, but has a layer 186 that serves as both a light emitting layer and an active layer.

[0171] As the layer 186 serving as both the light-emitting layer and the active layer, for example, a layer containing three materials: an n-type semiconductor that can be used in the active layer 183, a p-type semiconductor that can be used in the active layer 183, and a light-emitting substance that can be used in the light-emitting layer 193 can be used.

[0172] Furthermore, it is preferable that the absorption band on the lowest energy side of the absorption spectrum of the mixed material of n-type semiconductor and p-type semiconductor does not overlap with the maximum peak of the emission spectrum (PL spectrum) of the luminescent substance, and it is more preferable that they are sufficiently separated from each other.

[0173] In a light receiving / emitting device, a conductive film that transmits visible light is used for an electrode from which light is extracted, and a conductive film that reflects visible light is preferably used for an electrode from which light is not extracted.

[0174] When the light-receiving device is operated as a light-emitting device, the hole injection layer is a layer that injects holes from the anode to the hole transport layer. The hole injection layer is a layer that contains a material with high hole injection properties. As the material with high hole injection properties, an aromatic amine compound or a composite material containing a hole transport material and an acceptor material (electron accepting material) can be used.

[0175] When the light emitting / receiving device is operated as a light emitting device, the hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light emitting layer. When the light emitting / receiving device is operated as a light receiving device, the hole transport layer is a layer that transports holes generated in the active layer based on incident light to the anode. The hole transport layer is a layer containing a hole transport material. The hole transport material is a material having a density of 1×10 -6 cm 2 A material having a hole mobility of 100 / Vs or more is preferable. Note that other materials can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a material having a high hole transporting property such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, a furan derivative, etc.) or an aromatic amine (a compound having an aromatic amine skeleton) is preferable.

[0176] When the light emitting / receiving device is operated as a light emitting device, the electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light emitting layer. When the light emitting / receiving device is operated as a light receiving device, the electron transport layer is a layer that transports electrons generated in the active layer based on incident light to the cathode. The electron transport layer is a layer containing an electron transporting material. The electron transporting material is, for example, 1×10 -6 cm 2 A substance having an electron mobility of 100 / Vs or more is preferable. Note that, other substances may be used as long as they have a higher electron transporting property than holes. As the electron transporting material, a metal complex having a quinoline skeleton, a metal complex having a benzoquinoline skeleton, a metal complex having an oxazole skeleton, a metal complex having a thiazole skeleton, and the like, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other materials having a high electron transporting property such as π-electron deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds may be used.

[0177] When the light emitting / receiving device is operated as a light emitting device, the electron injection layer is a layer that injects electrons from the cathode to the electron transport layer. The electron injection layer is a layer containing a material with high electron injection properties. As the material with high electron injection properties, an alkali metal, an alkaline earth metal, or a compound thereof can be used. As the material with high electron injection properties, a composite material containing an electron transport material and a donor material (electron donor material) can also be used.

[0178] The light-emitting layer 193 is a layer containing a light-emitting substance. The light-emitting layer 193 can have one or more types of light-emitting substances. As the light-emitting substance, a substance that emits light of a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. In addition, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0179] Examples of the light-emitting material include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0180] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0181] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton, organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand, platinum complexes, and rare earth metal complexes.

[0182] The light-emitting layer 193 may contain one or more organic compounds (host materials, assist materials, etc.) in addition to a light-emitting substance (guest material). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material may be used. In addition, as the one or more organic compounds, a bipolar material or a TADF material may be used.

[0183] The light-emitting layer 193 preferably includes, for example, a phosphorescent material, and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. With this configuration, light emission can be efficiently obtained using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from an exciplex to a light-emitting material (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest energy absorption band of the light-emitting material, energy transfer becomes smooth and light emission can be efficiently obtained. With this configuration, high efficiency, low voltage operation, and long life of the light-emitting device can be simultaneously achieved.

[0184] As a combination of materials that form an exciplex, it is preferable that the HOMO level (highest occupied molecular orbital level) of the hole transporting material is equal to or higher than the HOMO level of the electron transporting material. It is 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.

[0185] The formation of an exciplex can be confirmed, for example, by comparing the emission spectrum of a hole transport material, the emission spectrum of an electron transport material, and the emission spectrum of a mixed film obtained by mixing these materials, and observing the phenomenon that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectrum of each material (or has a new peak on the longer wavelength side). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole transport material, the transient PL of an electron transport material, and the transient PL of a mixed film obtained by mixing these materials, and observing the difference in transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component than the transient PL lifetime of each material, or the proportion of delayed components becoming larger. In addition, the above-mentioned transient PL may be read as transient electroluminescence (EL). In other words, the formation of an exciplex can also be confirmed by comparing the transient EL of a hole transport material, the transient EL of an electron transport material, and the transient EL of a mixed film obtained by mixing these materials, and observing the difference in transient response.

[0186] The active layer 183 includes a semiconductor. Examples of the semiconductor include an inorganic semiconductor such as silicon, and an organic semiconductor including an organic compound. In this embodiment, an example in which an organic semiconductor is used as the semiconductor of 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, a vacuum deposition method), which is preferable because a common manufacturing device can be used.

[0187] The active layer 183 is made of an n-type semiconductor material such as fullerene (e.g., C 60 , C 70 Examples of electron-accepting organic semiconductor materials include organic semiconductor materials such as fullerene derivatives, etc. Fullerenes have a shape like a soccer ball, and this shape is energetically stable. Fullerenes have deep (low) HOMO and LUMO levels. Fullerenes have extremely high electron-accepting (acceptor) properties because of their deep LUMO level. Normally, when π-electron conjugation (resonance) spreads on a plane, as in benzene, electron-donating (donor) properties are high, but fullerenes have a spherical shape, so they have high electron-accepting properties despite the large spread of π-electrons. High electron-accepting properties are useful as light-receiving devices because they cause charge separation quickly and efficiently. C 60 , C 70 Both have a wide absorption band in the visible light region, especially C 70 is C 60 It is preferred because it has a larger π-electron conjugated system and a broad absorption band in the long wavelength region as compared to the above.

[0188] Furthermore, examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0189] Examples of the p-type semiconductor material of the active layer 183 include electron-donating organic semiconductor materials such as copper (II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin phthalocyanine (SnPc), and quinacridone.

[0190] Examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, and compounds having an aromatic amine skeleton. Examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indolocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives.

[0191] The HOMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the HOMO level of the electron-accepting organic semiconductor material, and the LUMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the LUMO level of the electron-accepting organic semiconductor material.

[0192] It is preferable to use a spherical fullerene as the electron-accepting organic semiconductor material, and an organic semiconductor material with a nearly planar shape as the electron-donating organic semiconductor material. Molecules with similar shapes tend to gather together, and when molecules of the same type aggregate, the energy levels of the molecular orbitals are close to each other, which can increase the carrier transportability.

[0193] For example, the active layer 183 is preferably formed by co-evaporation of an n-type semiconductor and a p-type semiconductor.

[0194] The layer 186 serving as both a light emitting layer and an active layer is preferably formed using the above-mentioned light emitting material, n-type semiconductor, and p-type semiconductor.

[0195] The hole injection layer 181, the hole transport layer 182, the active layer 183, the light emitting layer 193, the electron transport layer 184, the electron injection layer 185, and the layer serving as both the light emitting layer and the active layer 186 may be made of either a low molecular weight compound or a high molecular weight compound, and may contain an inorganic compound. Each layer may be formed by a method such as a deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, or a coating method.

[0196] Below, detailed structures of a light-emitting and receiving device and a light-emitting device included in a display device of one embodiment of the present invention will be described with reference to FIGS.

[0197] The display device of one embodiment of the present invention may be any of a top emission type that emits light in a direction opposite to the substrate on which the light-emitting device is formed, a bottom emission type that emits light toward the substrate on which the light-emitting device is formed, and a dual emission type that emits light to both sides.

[0198] 9 to 11, a top emission type display device will be described as an example.

[0199] [Configuration example 1] The display device shown in Figures 9A and 9B has, on a substrate 151, a light-emitting device 47B that emits blue (B) light, a light-emitting device 47G that emits green (G) light, and a light-receiving device 47R (PD) that emits red (R) light and has a light-receiving function, via a layer 55 having transistors.

[0200] 9A shows a case where the light emitting / receiving device 47R (PD) functions as a light emitting device. In FIG. 9A, an example is shown in which the light emitting device 47B emits blue light, the light emitting device 47G emits green light, and the light emitting / receiving device 47R (PD) emits red light.

[0201] Fig. 9B shows a case where the light receiving and emitting device 47R (PD) functions as a light receiving device. Fig. 9B shows an example in which the light receiving and emitting device 47R (PD) detects blue light emitted by the light emitting device 47B and green light emitted by the light emitting device 47G.

[0202] Each of the light emitting device 47B, the light emitting device 47G, and the light receiving and emitting device 47R (PD) has a pixel electrode 191 and a common electrode 115. In this embodiment, a case will be described as an example in which the pixel electrode 191 functions as an anode and the common electrode 115 functions as a cathode.

[0203] In this embodiment, similarly to the light emitting device, the light receiving and emitting device 47R (PD) will be described as having the pixel electrode 191 function as an anode and the common electrode 115 function as a cathode. In other words, the light receiving and emitting device 47R (PD) can detect light incident on the light receiving and emitting device 47R (PD), generate charges, and extract them as a current by driving the light receiving and emitting device 47R (PD) with a reverse bias applied between the pixel electrode 191 and the common electrode 115.

[0204] The common electrode 115 is used in common by the light emitting device 47B, the light emitting device 47G, and the light emitting and receiving device 47R (PD). The pixel electrodes 191 of the light emitting device 47B, the light emitting device 47G, and the light emitting and receiving device 47R (PD) are electrically insulated from each other (also referred to as being electrically separated).

[0205] The materials and thicknesses of the pairs of electrodes of the light emitting device 47B, the light emitting device 47G, and the light receiving and emitting device 47R (PD) can be made the same, which can reduce the manufacturing cost of the display device and simplify the manufacturing process.

[0206] The configuration of the display device shown in FIGS. 9A and 9B will be specifically described.

[0207] The light emitting device 47B has a buffer layer 192B, a light emitting layer 193B, and a buffer layer 194B in this order on a pixel electrode 191. The light emitting layer 193B has a light emitting material that emits blue light. The light emitting device 47B has a function of emitting blue light.

[0208] The light emitting device 47G has a buffer layer 192G, a light emitting layer 193G, and a buffer layer 194G in this order on a pixel electrode 191. The light emitting layer 193G has a light emitting material that emits green light. The light emitting device 47G has a function of emitting green light.

[0209] The light-receiving and light-emitting device 47R (PD) has a buffer layer 192R, an active layer 183, a light-emitting layer 193R, and a buffer layer 194R in this order on a pixel electrode 191. The light-emitting layer 193R has a light-emitting material that emits red light. The active layer 183 has an organic compound that absorbs light of a shorter wavelength than red light (for example, one or both of green light and blue light). Note that the active layer 183 may use an organic compound that absorbs not only visible light but also ultraviolet light. The light-receiving and light-emitting device 47R (PD) has a function of emitting red light. The light-receiving and light-emitting device 47R (PD) has a function of detecting the emission of at least one of the light-emitting device 47G and the light-emitting device 47B, and preferably has a function of detecting the emission of both of them.

[0210] The active layer 183 preferably contains an organic compound that does not easily absorb red light and absorbs light with a shorter wavelength than red light. This allows the light receiving and emitting device 47R (PD) to have a function of efficiently emitting red light and a function of accurately detecting light with a shorter wavelength than red light.

[0211] 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 laminated structure.

[0212] In the display devices shown in FIGS. 9A and 9B, the buffer layer, active layer, and light-emitting layer are layers that are fabricated separately for each device.

[0213] Each of the buffer layers 192R, 192G, and 192B may have one or both of a hole injection layer and a hole transport layer. Furthermore, the buffer layers 192R, 192G, and 192B may have an electron blocking layer. Each of the buffer layers 194B, 194G, and 194R may have one or both of an electron injection layer and an electron transport layer. Furthermore, the buffer layers 194R, 194G, and 194B may have a hole blocking layer. Note that, for the materials of each layer constituting the light emitting device, the description of each layer constituting the light receiving and emitting device described above can be referred to.

[0214] [Configuration example 2] 10A and 10B, the light emitting device 47B, the light emitting device 47G, and the light receiving and emitting device 47R (PD) may have a common layer between a pair of electrodes, which allows the light receiving and emitting devices to be built into the display device without significantly increasing the number of manufacturing steps.

[0215] The light-emitting device 47B, the light-emitting device 47G, and the light-receiving device 47R (PD) shown in FIG. 10A have a common layer 112 and a common layer 114 in addition to the configurations shown in FIGS. 9A and 9B.

[0216] The light-emitting device 47B, the light-emitting device 47G, and the light-receiving device 47R (PD) shown in Figure 10B differ from the configurations shown in Figures 9A and 9B in that they do not have buffer layers 192R, 192G, 192B and buffer layers 194R, 194G, 194B, but have common layers 112 and 114.

[0217] The common layer 112 may include one or both of a hole injection layer and a hole transport layer, and the common layer 114 may include one or both of an electron injection layer and an electron transport layer.

[0218] Each of the common layer 112 and the common layer 114 may have a single-layer structure or a laminated structure.

[0219] [Configuration example 3] The display device shown in FIG. 11A is an example in which the laminated structure shown in FIG. 8C is applied to a light receiving and emitting device 47R (PD).

[0220] The light emitting / receiving device 47R (PD) has, on a pixel electrode 191, a hole injection layer 181, an active layer 183, a hole transport layer 182R, a light emitting layer 193R, an electron transport layer 184, an electron injection layer 185, and a common electrode 115 in this order.

[0221] Hole injection layer 181, electron transport layer 184, electron injection layer 185, and common electrode 115 are layers common to light-emitting device 47G and light-emitting device 47B.

[0222] The light emitting device 47G has, on a 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.

[0223] The light emitting device 47B has, on a 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.

[0224] It is preferable that a microcavity structure is applied to the light-emitting device of the display device of this embodiment. Therefore, it is preferable that one of a pair of electrodes of the light-emitting device has an electrode (semi-transmissive / semi-reflective electrode) that is transparent and reflective to visible light, and the other has an electrode (reflective electrode) that is reflective to visible light. When the light-emitting device has a microcavity structure, the light emitted from the light-emitting layer is resonated between both electrodes, and the light emitted from the light-emitting device can be intensified.

[0225] The semi-transmitting / semi-reflective electrode may have a laminated structure of a reflective electrode and an electrode that is transparent to visible light (also called a transparent electrode). In this specification, the reflective electrode, which functions as a part of the semi-transmitting / semi-reflective electrode, may be referred to as a pixel electrode or a common electrode, and the transparent electrode may be referred to as an optical adjustment layer, but the transparent electrode (optical adjustment layer) may also function as a pixel electrode or a common electrode.

[0226] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode with a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more for a light emitting device. The visible light reflectance of the semi-transmissive / semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes is 1×10 -2 When a light emitting device that emits near-infrared light is used in the display device, the transmittance and reflectance of these electrodes for near-infrared light (light with a wavelength of 750 nm or more and 1300 nm or less) are also preferably within the above numerical ranges.

[0227] Each of the hole transport layers 182B, 182G, and 182R may have a function as an optical adjustment layer. Specifically, in the light emitting device 47B, it is preferable to adjust the thickness of the hole transport layer 182B so that the optical distance between the pair of electrodes is an optical distance that strengthens blue light. Similarly, in the light emitting device 47G, it is preferable to adjust the thickness of the hole transport layer 182G so that the optical distance between the pair of electrodes is an optical distance that strengthens green light. And, in the light receiving / emitting device 47R (PD), it is preferable to adjust the thickness of the hole transport layer 182R so that the optical distance between the pair of electrodes is an optical distance that strengthens red light. The layer used as the optical adjustment layer is not limited to the hole transport layer. In addition, when the semi-transmitting / 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.

[0228] [Configuration example 4] The display device shown in FIG. 11B is an example in which the laminated structure shown in FIG. 8D is applied to a light receiving and emitting device 47R (PD).

[0229] The light emitting / receiving device 47R (PD) has, on a pixel electrode 191, a hole injection layer 181, an active layer 183, a light emitting layer 193R, an electron transport layer 184, an electron injection layer 185, and a common electrode 115 in this order.

[0230] Hole injection layer 181, electron transport layer 184, electron injection layer 185, and common electrode 115 are layers common to light-emitting device 47G and light-emitting device 47B.

[0231] The light emitting device 47G has, on a 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.

[0232] The light emitting device 47B has, on a 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.

[0233] The hole transport layer is provided in the light emitting device 47G and the light emitting device 47B, but not in the light receiving / emitting device 47R (PD). In this way, in addition to the active layer and the light emitting layer, a layer may be provided in only one of the light emitting device and the light emitting / receiving device.

[0234] A detailed configuration of a display device according to one embodiment of the present invention will be described below with reference to FIGS.

[0235] [Display device 10A] 12A and 12B show cross-sectional views of the display device 10A.

[0236] The display device 10A includes a light emitting device 190B, a light emitting device 190G, and light receiving and emitting devices 190R and 190PD.

[0237] The light emitting device 190B has a pixel electrode 191, a buffer layer 192B, a light emitting layer 193B, a buffer layer 194B, and a common electrode 115. The light emitting device 190B has a function of emitting blue light 21B.

[0238] The light emitting device 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 device 190G has a function of emitting green light 21G.

[0239] The light emitting and receiving devices 190R and PD each have 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 receiving devices 190R and PD each have a function of emitting red light 21R and a function of detecting light 22.

[0240] Fig. 12A shows a case where the light emitting and receiving devices 190R and PD function as light emitting devices. Fig. 12A shows an example where the light emitting device 190B emits blue light, the light emitting device 190G emits green light, and the light emitting and receiving devices 190R and PD emit red light.

[0241] Fig. 12B illustrates a case where the light receiving and emitting devices 190R and PD function as light receiving devices. Fig. 12B illustrates an example in which the light receiving and emitting devices 190R and PD detect blue light emitted by the light emitting device 190B and green light emitted by the light emitting device 190G.

[0242] The pixel electrode 191 is located on the insulating layer 214. Ends of the pixel electrode 191 are covered with partition walls 216. Two adjacent pixel electrodes 191 are electrically insulated from each other by the partition wall 216 (also referred to as being electrically separated).

[0243] An organic insulating film is suitable for the partition 216. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. The partition 216 is a layer that transmits visible light. Although the details will be described later, a partition 217 that blocks visible light may be provided instead of the partition 216.

[0244] The display device 10A has, between a pair of substrates (substrate 151 and substrate 152), light receiving and emitting devices 190R and PD, a light emitting device 190G, a light emitting device 190B, a transistor 42, and the like.

[0245] The light receiving and emitting devices 190R and PD have a function of detecting light. Specifically, the light receiving and emitting devices 190R and PD are photoelectric conversion devices that receive light 22 incident from outside the display device 10A and convert it into an electrical signal. The light 22 can also be said to be light emitted by one or both of the light emitting devices 190G and 190B and reflected by an object. The light 22 may also be incident on the light receiving and emitting devices 190R and PD via a lens.

[0246] The light emitting device 190 has a function of emitting visible light. Specifically, the light emitting device 190 is an electroluminescent device that emits light toward the substrate 152 side by applying a voltage between the pixel electrode 191 and the common electrode 115 (see light 21G and light 21B).

[0247] The buffer layer 192, the light-emitting layer 193, and the buffer layer 194 can also be called organic layers (layers containing an organic compound) or EL layers. The pixel electrode 191 preferably has a function of reflecting visible light. The common electrode 115 has a function of transmitting visible light.

[0248] The pixel electrode 191 is electrically connected to the source or drain of the transistor 42 through an opening provided in the insulating layer 214. The transistor 42 has a function of controlling the driving of a light-emitting device or a light-receiving and light-emitting device.

[0249] At least a part of the circuit electrically connected to the light receiving and emitting devices 190R and PD is preferably formed of the same material and in the same process as the circuit electrically connected to the light emitting devices 190 of each color. This allows the display device to be thinner and the manufacturing process to be simplified compared to the case where the two circuits are formed separately.

[0250] The light-receiving and light-emitting devices 190R and PD and the light-emitting devices 190 of each color are preferably covered with a protective layer 195. In Fig. 12A and other figures, the protective layer 195 is provided in contact with the common electrode 115. Providing the protective layer 195 can suppress impurities from entering the light-receiving and light-emitting devices 190R and PD and the light-emitting devices of each color, thereby improving the light-receiving and light-emitting devices 190R and PD and the light-emitting devices of each color. In addition, the protective layer 195 and the substrate 152 are bonded together by the adhesive layer 142.

[0251] A light-shielding layer BM is provided on the surface of the substrate 152 facing the substrate 151. The light-shielding layer BM has openings at positions overlapping the light-emitting devices 190 of each color and at positions overlapping the light-receiving and light-emitting devices 190R and PD. Note that in this specification and the like, the positions overlapping with the light-emitting devices 190 specifically refer to positions overlapping with the light-emitting regions of the light-emitting devices 190. Similarly, the positions overlapping with the light-receiving and light-emitting devices 190R and PD specifically refer to positions overlapping with the light-emitting regions and light-receiving regions of the light-receiving and light-emitting devices 190R and PD.

[0252] As shown in FIG. 12B, the light emitted by the light emitting device 190 is reflected by an object, and the light receiving and emitting devices 190R and PD can detect the reflected light. However, the light emitted by the light emitting device 190 may be reflected inside the display device 10A and may be incident on the light receiving and emitting devices 190R and PD without passing through the object. The light shielding layer BM can suppress the influence of such stray light. For example, if the light shielding layer BM is not provided, the light 23 emitted by the light emitting device 190G may be reflected by the substrate 152, and the reflected light 24 may be incident on the light receiving and emitting devices 190R and PD. By providing the light shielding layer BM, it is possible to suppress the reflected light 24 from being incident on the light receiving and emitting devices 190R and PD. This can reduce noise and increase the sensitivity of the sensor using the light receiving and emitting devices 190R and PD.

[0253] The light-shielding layer BM may be made of a material that blocks light emitted from the light-emitting device. The light-shielding layer BM preferably absorbs visible light. For example, the light-shielding layer BM may be made of a black matrix using a metal material or a resin material containing a pigment (such as carbon black) or a dye. The light-shielding layer BM may have a laminated structure of a red color filter, a green color filter, and a blue color filter.

[0254] [Display device 10B] 13A differs from the display device 10A in that the light emitting device 190 and the light receiving and emitting devices 190R and PD do not have the buffer layer 192 and the buffer layer 194, but have the common layer 112 and the common layer 114, respectively. In the following description of the display device, description of the same configuration as the display device described above may be omitted.

[0255] The layered structure of the light emitting device 190B, the light emitting device 190G, and the light receiving and emitting devices 190R and PD is not limited to the configuration shown in the display devices 10A and 10B. For example, the layered structures shown in FIGS. 8 to 11 may be appropriately applied to each device.

[0256] [Display device 10C] Display device 10C shown in FIG. 13B differs from display device 10B in that it does not have substrate 151 and substrate 152, but has substrate 153, substrate 154, adhesive layer 155, and insulating layer 212.

[0257] The substrate 153 and the insulating layer 212 are bonded together by an adhesive layer 155. The substrate 154 and the protective layer 195 are bonded together by an adhesive layer 142.

[0258] The display device 10C is fabricated by transposing, onto a substrate 153, an insulating layer 212, a transistor 42, light receiving and emitting devices 190R / PD, a light emitting device 190, and the like, which are formed on a fabrication substrate. Each of the substrates 153 and 154 is preferably flexible. This can increase the flexibility of the display device 10C. For example, each of the substrates 153 and 154 is preferably made of a resin.

[0259] The substrates 153 and 154 may each be made of polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. One or both of the substrates 153 and 154 may be made of glass having a thickness sufficient to provide flexibility.

[0260] A film having high optical isotropy may be used for the substrate of the display device of this embodiment. Examples of the film having high optical isotropy include a triacetyl cellulose (TAC, also called cellulose triacetate) film, a cycloolefin polymer (COP) film, a cycloolefin copolymer (COC) film, and an acrylic film.

[0261] A more detailed configuration of the display device according to one embodiment of the present invention will be described below with reference to FIGS.

[0262] [Display device 100A] FIG. 14 shows a perspective view of the display device 100A, and FIG. 15 shows a cross-sectional view of the display device 100A.

[0263] The display device 100A has a configuration in which a substrate 152 and a substrate 151 are bonded together. In Fig. 14, the substrate 152 is indicated by a dashed line.

[0264] The display device 100A has a display unit 162, a circuit 164, wiring 165, etc. Fig. 14 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. 14 can also be said to be a display module having the display device 100A, an IC, and an FPC.

[0265] The circuit 164 can be, for example, a scanning line driver circuit.

[0266] The wiring 165 has a function of supplying signals and power to the display portion 162 and the circuit 164. The signals and power are input to the wiring 165 from the outside via the FPC 172 or from the IC 173.

[0267] 14 shows an example in which an IC 173 is provided on a substrate 151 by a chip on glass (COG) method or a chip on film (COF) method. For example, an IC having a scanning line driving circuit or a signal line driving circuit can be used as the IC 173. Note that the display device 100A and the display module may be configured without an IC. Also, the IC may be mounted on an FPC by a COF method or the like.

[0268] Figure 15 shows an example of a cross section of the display device 100A shown in Figure 14, cutting a portion of the area including the FPC 172, a portion of the area including the circuit 164, a portion of the area including the display unit 162, and a portion of the area including the end portion.

[0269] A display device 100A shown in FIG. 15 includes, between a substrate 151 and a substrate 152, a transistor 201, a transistor 205, a transistor 206, a transistor 207, a light emitting device 190B, a light emitting device 190G, and light receiving and emitting devices 190R and PD.

[0270] The substrate 152 and the insulating layer 214 are bonded via an adhesive layer 142. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light emitting device 190B, the light emitting device 190G, and the light receiving and emitting devices 190R and PD. In FIG. 15, a 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 sealing structure is applied. The adhesive layer 142 may be provided overlapping the light emitting device 190B, the light emitting device 190G, and the light receiving and emitting devices 190R and PD. In addition, 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.

[0271] The light-emitting device 190B has a layered structure in which a pixel electrode 191, a common layer 112, a light-emitting layer 193B, a common layer 114, and a common electrode 115 are layered in this order from the insulating layer 214 side. The pixel electrode 191 is connected to a conductive layer 222b of the transistor 207 through an opening provided in the insulating layer 214. The transistor 207 has a function of controlling the driving of the light-emitting device 190B. An end of the pixel electrode 191 is covered with a partition wall 216. The pixel electrode 191 contains a material that reflects visible light, and the common electrode 115 contains a material that transmits visible light.

[0272] The light-emitting device 190G has a layered structure in which a pixel electrode 191, a common layer 112, a light-emitting layer 193G, a common layer 114, and a common electrode 115 are layered in this order from the insulating layer 214 side. The pixel electrode 191 is connected to a conductive layer 222b of the transistor 206 through an opening provided in the insulating layer 214. The transistor 206 has a function of controlling the driving of the light-emitting device 190G.

[0273] The light emitting and receiving devices 190R and PD have a layered structure in which a pixel electrode 191, a common layer 112, an active layer 183, a light emitting layer 193R, a common layer 114, and a common electrode 115 are layered in this order from the insulating layer 214 side. The pixel electrode 191 is electrically connected to a conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The transistor 205 has a function of controlling the driving of the light emitting and receiving devices 190R and PD.

[0274] Light emitted from the light emitting device 190B, the light emitting device 190G, and the light receiving and emitting devices 190R and PD is emitted towards the substrate 152. Light is incident on the light receiving and emitting devices 190R and PD via the substrate 152 and the space 143. It is preferable that the substrate 152 is made of a material that is highly transparent to visible light.

[0275] The pixel electrode 191 can be manufactured using the same material and in the same process. The common layer 112, the common layer 114, and the common electrode 115 are used in common for the light-emitting device 190B, the light-emitting device 190G, and the light-receiving and light-emitting devices 190R and PD. The light-emitting and light-receiving devices 190R and PD have a configuration in which an active layer 183 is added to the configuration of a light-emitting device that emits red light. The light-emitting device 190B, the light-emitting device 190G, and the light-receiving and light-emitting devices 190R and PD can all have a common configuration except for the configurations of the active layer 183 and the light-emitting layers 193 of each color. This makes it possible to add a light-receiving function to the display unit 162 of the display device 100A without significantly increasing the number of manufacturing processes.

[0276] A light-shielding layer BM is provided on the surface of the substrate 152 facing the substrate 151. The light-shielding layer BM has openings at positions overlapping with the light-emitting device 190B, the light-emitting device 190G, and the light-receiving and light-emitting devices 190R and PD. By providing the light-shielding layer BM, the range in which the light-receiving and light-emitting devices 190R and PD detect light can be controlled. Furthermore, by having the light-shielding layer BM, it is possible to prevent light from being directly incident on the light-emitting device 190 from the light-emitting device 190 to the light-receiving and light-emitting devices 190R and PD without passing through an object. Therefore, a sensor with low noise and high sensitivity can be realized.

[0277] A transistor 201, a transistor 205, a transistor 206, and a transistor 207 are all formed over a substrate 151. These transistors can be manufactured using the same material and through the same process.

[0278] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 151 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistors. The insulating layer 214 is provided to cover the transistors and functions as a planarizing layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0279] It is preferable that at least one of the insulating layers covering the transistors is made of a material that is difficult for impurities such as water and hydrogen to diffuse into. This allows the insulating layer to function as a barrier layer. With this structure, it is possible to effectively prevent impurities from diffusing into the transistors from the outside, thereby improving the reliability of the display device.

[0280] It is preferable to use an inorganic insulating film for each of the insulating layers 211, 213, and 215. As the inorganic insulating film, for example, a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, an aluminum nitride film, or the like can be used. In addition, a hafnium oxide film, a hafnium oxynitride film, a hafnium nitride oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, a neodymium oxide film, or the like may be used. In addition, two or more of the above insulating films may be stacked. Note that a base film may be provided between the substrate 151 and the transistor. The above inorganic insulating film may also be used for the base film.

[0281] Here, the organic insulating film often has a lower barrier property than the inorganic insulating film. Therefore, it is preferable that the organic insulating film has an opening near the end of the display device 100A. This makes it possible to suppress impurities from entering through the organic insulating film from the end of the display device 100A. Alternatively, the organic insulating film may be formed so that the end of the organic insulating film is located 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.

[0282] An organic insulating film is suitable for the insulating layer 214 that functions as a planarizing layer. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0283] 15, an opening is formed in the insulating layer 214. This makes it possible to prevent impurities from entering the display unit 162 from the outside through the insulating layer 214, even when an organic insulating film is used for the insulating layer 214. This makes it possible to improve the reliability of the display device 100A.

[0284] The transistor 201, the transistor 205, the transistor 206, and the transistor 207 each have a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a conductive layer 222a and a conductive layer 222b functioning as a source and a drain, a semiconductor layer 231, an insulating layer 213 functioning as a gate insulating layer, and a conductive layer 223 functioning as a gate. Here, the same hatched pattern is applied 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.

[0285] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. In addition, either a top-gate type or a bottom-gate type transistor may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0286] The transistors 201, 205, 206, and 207 each have a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected and supplied with the same signal to drive the transistor. Alternatively, the threshold voltage of the transistor may be controlled by supplying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0287] The crystallinity of a semiconductor material used in a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor partially having a crystalline region) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0288] The semiconductor layer of the transistor preferably contains a metal oxide (also referred to as an oxide semiconductor). Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single crystal silicon).

[0289] The semiconductor layer preferably contains, for example, indium, M (M is one or more 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 selected from aluminum, gallium, yttrium, and tin.

[0290] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) as the semiconductor layer.

[0291] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such In-M-Zn oxides include In:M:Zn=1:1:1 or a composition thereabout, In:M:Zn=1:1:1.2 or a composition thereabout, In:M:Zn=2:1:3 or a composition thereabout, In:M:Zn=3:1:2 or a composition thereabout, In:M:Zn=4:2:3 or a composition thereabout, In:M:Zn=4:2:4.1 or a composition thereabout, In:M:Zn=5:1:3 or a composition thereabout, In:M:Zn=5:1:6 or a composition thereabout, In:M:Zn=5:1:7 or a composition thereabout, In:M:Zn=5:1:8 or a composition thereabout, In:M:Zn=6:1:6 or a composition thereabout, In:M:Zn=5:2:5 or a composition thereabout, etc. The term "nearby composition" includes a range of ±30% of the desired atomic ratio.

[0292] For example, when describing a composition with an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, it includes the case where, when the atomic ratio of In is 4, 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. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, it includes the case where, when the atomic ratio of In is 5, the atomic ratio of Ga is more than 0.1 and 2 or less, and the atomic ratio of Zn is 5 or more and 7 or less. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, it includes the case where, when the atomic ratio of In is 1, the atomic ratio of Ga is more than 0.1 and 2 or less, and the atomic ratio of Zn is more than 0.1 and 2 or less.

[0293] The transistors included in the circuit 164 and the transistors included in the display portion 162 may have the same structure or different structures. The transistors included in the circuit 164 may all have the same structure or may have two or more types. Similarly, the transistors included in the display portion 162 may all have the same structure or may have two or more types.

[0294] A connection portion 204 is provided in an area of ​​the substrate 151 where the substrate 152 does not overlap. In the connection portion 204, the wiring 165 is electrically connected to the FPC 172 via a conductive layer 166 and a connection layer 242. On the upper surface of the connection portion 204, the conductive layer 166 obtained by processing the same conductive film as the pixel electrode 191 is exposed. This allows the connection portion 204 and the FPC 172 to be electrically connected via the connection layer 242.

[0295] Various optical members can be disposed on the outside of the substrate 152. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light collecting film. In addition, an antistatic film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses the occurrence of scratches due to use, an impact absorbing layer, and the like may be disposed on the outside of the substrate 152.

[0296] The substrate 151 and the substrate 152 can each be made of glass, quartz, ceramic, sapphire, resin, etc. When the substrate 151 and the substrate 152 are made of a flexible material, the flexibility of the display device can be increased.

[0297] As the adhesive layer, various curing adhesives such as a photo-curing adhesive such as an ultraviolet curing adhesive, a reaction curing adhesive, a heat curing adhesive, and an anaerobic adhesive can be used. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. In particular, a material with low moisture permeability such as epoxy resin is preferable. A two-liquid mixed resin may also be used. An adhesive sheet or the like may also be used.

[0298] The connection layer may be made of an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0299] Materials that can be used for the gate, source, and drain of a transistor as well as conductive layers such as various wirings and electrodes that constitute a display device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys containing such metals as main components, etc. Films containing these materials can be used as a single layer or a laminated structure.

[0300] As the conductive material having light transmitting properties, 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. Note that when using metal materials or alloy materials (or their nitrides), it is preferable to make them thin enough to have light transmitting properties. Also, a laminated film of the above materials can be used as the conductive layer. For example, it is preferable to use a laminated film of an alloy of silver and magnesium and indium tin oxide, because it can increase the conductivity. These can also be used for conductive layers such as various wirings and electrodes constituting a display device, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) of a light emitting device and a light receiving and emitting device.

[0301] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0302] [Display device 100B] FIG. 16 shows a cross-sectional view of the display device 100B.

[0303] The display device 100B differs from the display device 100A mainly in that it has a protective layer 195. Detailed descriptions of configurations similar to those of the display device 100A will be omitted.

[0304] By providing a protective layer 195 covering the light-emitting device 190B, the light-emitting device 190G, and the light-emitting and receiving devices 190R and PD, it is possible to prevent impurities such as water from entering the light-emitting device 190B, the light-emitting device 190G, and the light-emitting and receiving devices 190R and PD, and to improve the reliability of the light-emitting device 190B, the light-emitting device 190G, and the light-emitting and receiving devices 190R and PD.

[0305] In a region 228 near the end of the display device 100B, it is preferable that the insulating layer 215 and the protective layer 195 contact each other through the opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating film of the insulating layer 215 and the inorganic insulating film of the protective layer 195 contact each other. This makes it possible to suppress impurities from entering the display unit 162 from the outside through the organic insulating film. Therefore, it is possible to improve the reliability of the display device 100B.

[0306] The protective layer 195 may have a single layer or a laminated structure, and may have, for example, a three-layer structure having an inorganic insulating layer on the common electrode 115, an organic insulating layer on the inorganic insulating layer, and an inorganic insulating layer on the organic insulating layer. In this case, it is preferable that the end of the inorganic insulating layer extends outward beyond the end of the organic insulating layer.

[0307] Furthermore, a lens may be provided in the area overlapping with the light receiving and emitting devices 190R and PD, thereby improving the sensitivity and accuracy of the sensor using the light receiving and emitting devices 190R and PD.

[0308] 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.

[0309] Specifically, the lens may be made of a resin containing chlorine, bromine, or iodine, a resin containing a heavy metal atom, a resin containing an aromatic ring, or a resin containing sulfur. Alternatively, the lens may be made of a material containing a resin and nanoparticles of a material with a higher refractive index than the resin. Titanium oxide or zirconium oxide may be used for the nanoparticles.

[0310] In addition, cerium oxide, hafnium oxide, lanthanum oxide, magnesium oxide, niobium oxide, tantalum oxide, titanium oxide, yttrium oxide, zinc oxide, oxides containing indium and tin, or oxides containing indium, gallium, and zinc can be used for the lens. Alternatively, zinc sulfide can be used for the lens.

[0311] In the display device 100B, the protective layer 195 and the substrate 152 are bonded together by an adhesive layer 142. The adhesive layer 142 is provided so as to overlap the light-emitting device 190B, the light-emitting device 190G, and the light-receiving and light-emitting devices 190R and PD, respectively, and a solid sealing structure is applied to the display device 100B.

[0312] [Display device 100C] FIG. 17A shows a cross-sectional view of the display device 100C.

[0313] The display device 100C differs from the display device 100B in the structure of the transistors.

[0314] The display device 100C includes a transistor 208, a transistor 209, and a transistor 210 over a substrate 151.

[0315] The transistor 208, the transistor 209, and the transistor 210 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a semiconductor layer 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 functioning as a gate insulating layer, a conductive layer 223 functioning as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located between the conductive layer 223 and the channel formation region 231i.

[0316] The conductive layer 222a and the conductive layer 222b are connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215, respectively. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0317] The pixel electrode 191 of the light emitting device 190G is electrically connected to one of a pair of low resistance regions 231n of the transistor 208 via the conductive layer 222b.

[0318] The pixel electrodes 191 of the light emitting and receiving devices 190R and 190PD are electrically connected to the other of the pair of low resistance regions 231n of the transistor 209 via the conductive layer 222b.

[0319] 17A shows an example in which the insulating layer 225 covers the upper surface and side surface of the semiconductor layer. On the other hand, in FIG. 17B, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231, but does not overlap with the low-resistance region 231n. For example, the structure shown in FIG. 17B can be manufactured by processing the insulating layer 225 using the conductive layer 223 as a mask. In FIG. 17B, 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 connected to the low-resistance region 231n through the openings in the insulating layer 215. Furthermore, an insulating layer 218 covering the transistor may be provided on the conductive layer 222a and the conductive layer 222b.

[0320] Furthermore, the display device 100C differs from the display device 100B in that it does not have the substrate 151 and the substrate 152, but has the substrate 153, the substrate 154, the adhesive layer 155, and the insulating layer 212.

[0321] The substrate 153 and the insulating layer 212 are bonded together by an adhesive layer 155. The substrate 154 and the protective layer 195 are bonded together by an adhesive layer 142.

[0322] The display device 100C is fabricated by transferring, onto a substrate 153, an insulating layer 212, a transistor 208, a transistor 209, a transistor 210, light receiving and emitting devices 190R and PD, a light emitting device 190G, and the like, which are formed on a fabrication substrate. Each of the substrates 153 and 154 is preferably flexible. This can increase the flexibility of the display device 100C.

[0323] For the insulating layer 212, the inorganic insulating film that can be used for the insulating layers 211 and 215 can be used.

[0324] As described above, in the display device of the present embodiment, a light receiving / emitting device is provided in each subpixel that exhibits one of the colors instead of a light emitting device. The light receiving / emitting device functions as both a light emitting device and a light receiving device, so that a pixel can be given a light receiving function without increasing the number of subpixels included in the pixel. In addition, a light receiving function can be given to a pixel without reducing the resolution of the display device or the aperture ratio of each subpixel.

[0325] This embodiment mode can be combined with other embodiment modes as appropriate.

[0326] (Embodiment 3) In this embodiment, a light-emitting device that can be used for a display device of one embodiment of the present invention will be described with reference to FIGS.

[0327] The light-emitting device shown in Fig. 18A has an anode 101, an EL layer 103, and a cathode 102. The light-emitting device shown in Fig. 18A has a single structure in which one EL layer is sandwiched between a pair of electrodes. The EL layer 103 has, from the anode 101 side, a hole injection layer 121, a hole transport layer 122, a light-emitting layer 123, an electron transport layer 124, and an electron injection layer 125. Although not shown in Figs. 18A to 18D, the light-emitting device may have an optical adjustment layer.

[0328] The anode 101, the cathode 102, the hole injection layer 121, the hole transport layer 122, the light emitting layer 123, the electron transport layer 124, and the electron injection layer 125 may each have a single layer structure or a laminated structure.

[0329] The light-emitting device shown in Fig. 18B has an anode 101, an EL layer 103a, a charge generating layer 104, an EL layer 103b, and a cathode 102. The light-emitting device shown in Fig. 18B has a tandem structure having a charge generating layer 104 between two EL layers.

[0330] Each EL layer in a light-emitting device with a tandem structure can have the same structure as the EL layer in the light-emitting device with a single structure shown in FIG. 18A, FIG. 18C, FIG. 18D, etc.

[0331] The charge generation layer 104 has a function of injecting electrons into one of the EL layers 103a and 103b and injecting holes into the other when a voltage is applied between the anode 101 and the cathode 102. Therefore, in Fig. 18B, when a voltage is applied to the anode 101 so that the potential is higher than that of the cathode 102, electrons are injected from the charge generation layer 104 into the EL layer 103a and holes are injected into the EL layer 103b.

[0332] In a light-emitting device with a tandem structure, the light-emitting color of each EL layer is made different, so that the light-emitting device as a whole can emit light of a desired color. For example, in a light-emitting device having two EL layers, a light-emitting device that emits white light can be obtained by obtaining red and green light from one EL layer and blue light from the other EL layer. For example, in a light-emitting device having three EL layers, a light-emitting device that emits white light can be obtained by obtaining blue light from the first EL layer, green light from the second EL layer, and red light from the third EL layer. For example, in a light-emitting device having three EL layers, a light-emitting device that emits white light can be obtained by obtaining blue light from the first EL layer, yellow, yellow-green, or green and red light from the second EL layer on the first EL layer, and blue light from the third EL layer on the second EL layer. For example, in a light-emitting device having four EL layers, a light-emitting device that emits white light as a whole can be obtained by obtaining blue light emission from the first EL layer, yellow, yellow-green, or green light emission from one of the second EL layer and the third EL layer on the first EL layer, red light emission from the other, and blue light emission from the fourth EL layer on the second EL layer and the third EL layer.

[0333] The hole transport layer 122 of the light emitting device shown in FIGS. 18C and 18D has a two-layer structure including a hole transport layer 122a on the hole injection layer 121 side and a hole transport layer 122b on the light emitting layer 123 side.

[0334] The electron transport layer 124 of the light emitting device shown in FIG. 18D has a two-layer structure including an electron transport layer 124a on the light emitting layer 123 side and an electron transport layer 124b on the electron injection layer 125 side.

[0335] At least one of the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer of the light-emitting device of this embodiment can be a layer common to the light-receiving and light-emitting device. Therefore, the manufacturing process can be reduced compared to the case where the layers are formed separately, and the light-emitting device and the light-receiving and light-emitting device can be formed on the same surface.

[0336] Materials that can be used in light-emitting devices are described below.

[0337] <Electrode> As a material for forming a pair of electrodes of a light-emitting device, metals, alloys, electrically conductive compounds, and mixtures thereof can be appropriately used. Specifically, In-Sn oxide (also called ITO), In-Si-Sn oxide (also called ITSO), In-Zn oxide, and In-W-Zn oxide can be mentioned. In addition, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), and alloys containing these in appropriate combinations can also be used. In addition, elements belonging to Group 1 or 2 of the periodic table not exemplified above (e.g., lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu) and ytterbium (Yb), alloys containing appropriate combinations of these, graphene, etc. can be used.

[0338] When a light-emitting device having a microcavity structure is to be fabricated, a reflective electrode and a semi-transmissive / semi-reflective electrode are used. Therefore, a single or multiple desired conductive materials can be used to form a single layer or a multilayer structure. The electrodes can be fabricated by sputtering or vacuum deposition.

[0339] <Hole injection layer> The hole injection layer 121 preferably comprises a first compound and a second compound.

[0340] The first compound is an electron-accepting material (acceptor material) and has electron-accepting properties toward the second compound.

[0341] The second compound is a hole transporting material that has a higher ability to transport holes than electrons.

[0342] The highest occupied molecular orbital level (HOMO level) of the second compound is preferably relatively low (deep). Specifically, the HOMO level of the second compound is preferably -5.7 eV or more and -5.4 eV or less. The relatively low HOMO level of the second compound is preferable because it facilitates the injection of holes into the hole transport layer 122.

[0343] As the first compound, an organic compound having an electron-withdrawing group (particularly a halogen group such as a fluoro group or a cyano group) can be used.

[0344] As the first compound, for example, an organic acceptor such as a quinodimethane derivative, a chloranil derivative, or a hexaazatriphenylene derivative can be used.

[0345] The second compound preferably has a hole transporting skeleton, and the hole transporting skeleton is preferably a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton, which does not make the HOMO level of the hole transporting material too high (shallow).

[0346] The second compound preferably has at least one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. The second compound may be an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group.

[0347] It is preferable that the second compound has an N,N-bis(4-biphenyl)amino group, since a light-emitting device having a long life can be produced.

[0348] <Hole transport layer> The hole transport layer 122 is a layer that transports the holes injected by the hole injection layer 121 to the light emitting layer 123 .

[0349] The hole transport layer 122 preferably comprises a third compound.

[0350] The third compound is a hole transporting material. As the hole transporting material, the hole transporting material that can be used for the second compound can be used.

[0351] The HOMO level of the third compound is preferably equal to or lower than the HOMO level of the second compound, and the difference between the HOMO levels of the third compound and the second compound is preferably within 0.2 eV.

[0352] Each of the second compound and the third compound preferably has at least one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton.

[0353] It is preferable that the second compound and the third compound have the same hole transporting skeleton (particularly, a dibenzofuran skeleton) since this facilitates the injection of holes.

[0354] It is more preferable that the second compound and the third compound are the same, since this allows smooth hole injection.

[0355] When the hole transport layer 122 has a laminated structure, each layer constituting the hole transport layer 122 is a layer that transports holes to the light emitting layer 123 .

[0356] The hole transport layer 122a in FIGS. 18C and 18D may have a similar structure to the hole transport layer 122 in FIG. 18A.

[0357] It is preferable that the hole transport layer 122b in FIG. 18C and FIG. 18D (that is, the layer of the hole transport layer 122 located closest to the light emitting layer 123) has a function as an electron blocking layer.

[0358] The hole transport layer 122b preferably comprises a fourth compound.

[0359] The fourth compound is a hole transporting material. As the hole transporting material, the hole transporting material that can be used for the second compound can be used.

[0360] The HOMO level of the fourth compound is preferably lower than the HOMO level of the third compound, and the difference between the HOMO levels of the fourth compound and the third compound is preferably within 0.2 eV.

[0361] Each of the second compound, the third compound, and the fourth compound preferably has at least one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton.

[0362] It is preferable that the second compound, the third compound, and the fourth compound have the same hole transporting skeleton (particularly a dibenzofuran skeleton) because this facilitates the injection of holes.

[0363] As described above, when the second compound and the third compound (and further the fourth compound) have a small difference in HOMO level or have a hole-transporting skeleton (preferably the same hole-transporting skeleton), holes can be smoothly injected into the hole injection layer and the hole transport layer, and an increase in driving voltage and an insufficient state of holes in the light-emitting layer 123 can be prevented.

[0364] <Light-emitting layer> The light-emitting layer is a layer containing a light-emitting substance. The materials and structures that can be used for the light-emitting layer of the light-receiving and light-emitting device in Embodiment 1 can be applied to the light-emitting layer.

[0365] <Electron transport layer> The electron transport layer 124 is a layer that transports the electrons injected from the cathode 102 to the light emitting layer 123 .

[0366] The electron transport layer 124 includes an electron transport material and a first substance.

[0367] Electron transporting materials have a higher ability to transport electrons than holes.

[0368] The electron transporting material used in the electron transport layer 124 preferably has a highest occupied molecular orbital level (HOMO level) of −6.0 eV or higher.

[0369] The electron transport material used in the electron transport layer 124 has an electron mobility of 1×10 -7 cm 2 / Vs or more 1×10 -5 cm 2 / Vs or less, and 1×10 -7 cm 2 / Vs or more 5×10 -5 cm 2 It is more preferable that the Vs be equal to or less than / Vs.

[0370] It is preferable that the electron mobility of the electron transporting material used in the electron transporting layer 124 at a square root of the electric field strength [V / cm] of 600 is smaller than the electron mobility of the host material in the light-emitting layer 123 at a square root of the electric field strength [V / cm] of 600. By reducing the electron transporting property in the electron transporting layer 124, the amount of electrons injected into the light-emitting layer 123 can be controlled, and the light-emitting layer 123 can be prevented from becoming an electron excess state.

[0371] The electron transporting material used in the electron transport layer 124 preferably has an anthracene skeleton, and more preferably has an anthracene skeleton and a heterocyclic skeleton. The heterocyclic skeleton is preferably a nitrogen-containing five-membered ring skeleton. The nitrogen-containing five-membered ring skeleton is particularly preferably a nitrogen-containing five-membered ring skeleton containing two heteroatoms in the ring, such as a pyrazole ring, an imidazole ring, an oxazole ring, or a thiazole ring.

[0372] The first substance is a metal, a metal salt, a metal oxide, or an organometallic salt.

[0373] The metals include alkali metals, alkaline earth metals, and rare earth metals, such as Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba.

[0374] Examples of metal salts include halides of the above metals and carbonates of the above metals, specifically LiF, NaF, KF, RbF, CsF, MgF2, CaF2, SrF2, BaF2, LiCl, NaCl, KCl, RbCl, CsCl, MgCl2, CaCl2, SrCl2, BaCl2, Li2CO3, Cs2CO3, etc.

[0375] Examples of metal oxides include oxides of the above metals, specifically Li2O, Na2O, Cs2O, MgO, CaO, etc.

[0376] The organometallic salts include, for example, organometallic complexes.

[0377] The first substance is preferably an organometallic complex having an alkali metal or alkaline earth metal.

[0378] The first substance is preferably an organometallic complex having a nitrogen- and oxygen-containing ligand and an alkali metal or alkaline earth metal.

[0379] The first substance is preferably an organometallic complex having a quinolinol ligand and an alkali metal or alkaline earth metal.

[0380] Examples of the organometallic complex include 8-quinolinolato lithium (abbreviation: Liq), 8-quinolinolato sodium (abbreviation: Naq), 8-quinolinolato potassium (abbreviation: Kq), bis(8-quinolinolato) magnesium (abbreviation: Mgq2), and bis(8-quinolinolato) zinc (abbreviation: Znq2).

[0381] As the first substance, Liq is particularly preferable.

[0382] 18D, the electron transport layer 124 may have an electron transport layer 124a on the light-emitting layer 123 side and an electron transport layer 124b on the cathode 102 side. The electron transport layer 124a and the electron transport layer 124b preferably have different concentration ratios of the electron transport material and the first substance. For example, the electron transport layer 124a preferably has a higher concentration of the first substance than the electron transport layer 124b.

[0383] <Electron injection layer> The electron injection layer 125 is a layer that increases the efficiency of electron injection from the cathode 102. It is preferable that the difference between the work function value of the material of the cathode 102 and the LUMO level value of the material used in the electron injection layer 125 is small (within 0.5 eV).

[0384] <Charge generation layer> The charge generating layer 104 has a function of injecting electrons into the EL layer 103a and injecting holes into the EL layer 103b when a voltage is applied between the anode 101 and the cathode 102.

[0385] The charge generating layer 104 may be configured to contain a hole transport material and an acceptor material, or may be configured to contain an electron transport material and a donor material. By forming the charge generating layer 104 with such a configuration, it is possible to suppress an increase in driving voltage when an EL layer is laminated.

[0386] [Light-emitting model for light-emitting devices] A light emission model in the light emitting device of this embodiment will be described.

[0387] Here, a light emission model of a light emitting device will be described using the hole transport layer 122, the light emitting layer 123, and the electron transport layer 124 shown in Fig. 18A. The light emitting device is not limited to the configuration shown in Fig. 18A, and the light emission model can be applied to other configurations.

[0388] When the light-emitting layer 123 becomes in an electron excess state, as shown in FIG. 19A, a light-emitting region 123-1 is formed in a localized region in the light-emitting layer 123. In other words, the width of the light-emitting region 123-1 in the light-emitting layer 123 is narrow. Therefore, electrons (e - ) and Hall (h + ) and accelerates deterioration. Furthermore, electrons that cannot recombine in the light-emitting layer 123 pass through the light-emitting layer 123, which may reduce the lifetime or light-emitting efficiency.

[0389] On the other hand, in the light-emitting device of one embodiment of the present invention, the width of the light-emitting region 123-1 in the light-emitting layer 123 can be increased by reducing the electron-transport property of the electron-transport layer 124 (FIGS. 19B and 19C). By increasing the width of the light-emitting region 123-1, the recombination region of electrons and holes in the light-emitting layer 123 can be dispersed. Thus, a light-emitting device with a long lifetime and high light-emitting efficiency can be provided.

[0390] 19B, in the light-emitting device according to one embodiment of the present invention, the recombination region may extend to the electron transport layer 124 side in the early stage of driving. In FIG. 19B, the recombination region in the electron transport layer 124 is shown as region 124-1. Specifically, in the light-emitting device according to one embodiment of the present invention, the hole injection barrier is small in the early stage of driving and the electron transport property of the electron transport layer 124 is relatively low, so that the light-emitting region 123-1 (i.e., the recombination region) is formed throughout the light-emitting layer 123, and a recombination region may also be formed in the electron transport layer 124.

[0391] In addition, since the HOMO level of the electron transport material contained in the electron transport layer 124 is relatively high at −6.0 eV or higher, some of the holes may reach the electron transport layer 124 and recombine in the electron transport layer 124. This phenomenon may also occur when the difference in HOMO level between the host material (or assist material) contained in the light-emitting layer 123 and the electron transport material contained in the electron transport layer 124 is within 0.2 eV.

[0392] As shown in FIG. 19C, in the light-emitting device according to one embodiment of the present invention, as the driving time passes, the carrier balance changes, and recombination in the electron transport layer 124 is less likely to occur. By suppressing recombination in the electron transport layer 124 while the light-emitting region 123-1 is formed over the entire light-emitting layer 123, the energy of the recombined carriers can be effectively contributed to light emission. Therefore, the luminance can be increased compared to the initial driving stage. This increase in luminance offsets the rapid decrease in luminance that occurs in the initial driving stage of the light-emitting device, that is, the so-called initial deterioration, and thus a light-emitting device with small initial deterioration and long driving life can be provided. Note that in this specification and the like, the above-mentioned light-emitting device may be referred to as a Recombination-Site Tailoring Injection structure (ReSTI structure).

[0393] Here, the normalized luminance over time for the light-emitting device of the present embodiment and the comparative light-emitting device will be described with reference to Fig. 19D. In Fig. 19D, the thick solid line and the thick dashed line are degradation curves of the normalized luminance for the light-emitting device of the present embodiment, and the thick dashed line is the degradation curve of the normalized luminance for the comparative light-emitting device.

[0394] 19D, the light emitting device of the present embodiment and the comparative light emitting device have different slopes of the degradation curves of normalized luminance. Specifically, the slope θ2 of the degradation curve of the light emitting device of the present embodiment is smaller than the slope θ1 of the degradation curve of the comparative light emitting device.

[0395] As shown in FIG. 19D, the light-emitting device according to one embodiment of the present invention may have a maximum value (thick solid line) in a luminance deterioration curve obtained by a drive test under a constant current density condition. That is, the light-emitting device according to one embodiment of the present invention may exhibit a behavior in which the luminance increases with time. This behavior can offset the rapid deterioration at the beginning of drive (so-called initial deterioration). However, the light-emitting device according to one embodiment of the present invention is not limited to the above, and may, for example, not have a maximum value of luminance, in other words, the slope of the deterioration curve can be made small without causing an increase in luminance, as shown by the thick dashed dotted line in FIG. 19D. Therefore, by configuring the light-emitting device to exhibit this behavior, the initial deterioration of the light-emitting device can be reduced and the drive life can be made very long.

[0396] Note that when the degradation curve having a maximum value is differentiated, there is a portion where the value is 0. Therefore, a light-emitting device having a portion where the differential of the degradation curve is 0 can be rephrased as a light-emitting device according to one embodiment of the present invention.

[0397] In the light-emitting device according to one embodiment of the present invention, the electron-transport layer 124 preferably has a portion in which the mixture ratio (concentration) of the electron-transport material and the first substance is different in the thickness direction. Specifically, it preferably has a portion in which the mixture ratio (concentration) of the electron-transport material and the metal, the metal salt, the metal oxide, or the organometallic complex is different.

[0398] The concentration of the first substance in the electron transport layer 124 can be estimated from the amount of atoms or molecules detected by time-of-flight secondary ion mass spectrometry (ToF-SIMS). In a portion composed of the same two types of materials but with different mixing ratios, the magnitude of the values ​​detected by ToF-SIMS analysis corresponds to the amount of the atoms or molecules of interest present. Therefore, by comparing the detected amounts of the electron transport material and the organometallic complex, the magnitude of the mixing ratio can be estimated.

[0399] The content of the first substance in the electron transport layer 124 is preferably lower on the cathode 102 side than on the anode 101 side. In other words, the electron transport layer 124 is preferably formed so that the concentration of the first substance increases from the cathode 102 side toward the anode 101 side. That is, the electron transport layer 124 has a portion where the concentration of the electron transport material is lower on the light-emitting layer 123 side than on the portion where the concentration of the electron transport material is higher. In other words, the electron transport layer 124 has a portion where the concentration of the first substance is higher on the light-emitting layer 123 side than on the portion where the concentration of the first substance is lower.

[0400] In the electron transport layer 124, the electron mobility in a portion where the concentration of the electron transport material is high (a portion where the concentration of the first substance is low) is 1×10 -7 cm 2 / Vs or more 5×10 -5 cm 2 It is preferable that the value is equal to or less than / Vs.

[0401] For example, the content (concentration) of the first substance in the electron transport layer 124 can be configured as shown in Figures 20A to 20D. Note that Figures 20A and 20B show a case where there is no clear boundary in the electron transport layer 124, and Figures 20C and 20D show a case where there is a clear boundary in the electron transport layer 124.

[0402] When there is no clear boundary in the electron transport layer 124, the concentrations of the electron transport material and the first substance change continuously as shown in FIG. 20A and FIG. 20B. When there is a clear boundary in the electron transport layer 124, the concentrations of the electron transport material and the first substance change stepwise as shown in FIG. 20C and FIG. 20D. Note that when the concentrations of the electron transport material and the first substance change stepwise, it is suggested that the electron transport layer 124 is composed of multiple layers. For example, FIG. 20C shows a case where the electron transport layer 124 has a two-layer stacked structure, and FIG. 20D shows a case where the electron transport layer 124 has a three-layer stacked structure. Note that in FIG. 20C and FIG. 20D, the dashed lines show the boundary regions of multiple layers.

[0403] The change in carrier balance in the light-emitting device according to one embodiment of the present invention is believed to be brought about by a change in the electron mobility of the electron transport layer 124 .

[0404] In the light-emitting device of one embodiment of the present invention, a concentration difference of the first substance exists inside the electron-transport layer 124. The electron-transport layer 124 has a region where the concentration of the first substance is high between a region where the concentration of the first substance is low and the light-emitting layer 123. That is, the region where the concentration of the first substance is low is located closer to the cathode 102 than the region where the concentration of the first substance is high.

[0405] The light-emitting device according to one embodiment of the present invention having the above-described structure has a very long lifetime. In particular, when the initial luminance is set to 100%, the time until the luminance reaches 95% (also referred to as LT95) can be made extremely long.

[0406] This embodiment mode can be combined with other embodiment modes as appropriate.

[0407] (Embodiment 4) In this embodiment, a metal oxide (also referred to as an oxide semiconductor) which can be used for the OS transistor described in the above embodiment will be described.

[0408] The metal oxide preferably contains at least indium or zinc. In particular, it is preferable that the metal oxide contains indium and zinc. In addition to these, it is preferable that the metal oxide contains aluminum, gallium, yttrium, tin, etc. Furthermore, the metal oxide may contain one or more elements selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, etc.

[0409] Moreover, 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.

[0410] <Classification of crystal structures> Examples of the crystal structure of an oxide semiconductor include amorphous (including completely amorphous), c-axis-aligned crystalline (CAAC), nanocrystalline (nc), cloud-aligned composite (CAC), single crystal, and polycrystal.

[0411] 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 an XRD spectrum obtained by a GIXD (Grazing-Incidence XRD) measurement. The GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0412] For example, in the case of a quartz glass substrate, the peak shape of the XRD spectrum is almost symmetric. On the other hand, in the case of an IGZO film having a crystalline structure, the peak shape of the XRD spectrum is asymmetric. The asymmetric peak shape of the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetric, the film or substrate cannot be said to be in an amorphous state.

[0413] The crystal structure of a film or substrate can be evaluated by a diffraction pattern (also called a nanobeam electron diffraction pattern) observed by nanobeam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, and it can be confirmed that the quartz glass is in an amorphous state. In addition, a spot-like pattern is observed in the diffraction pattern of an IGZO film formed at room temperature, rather than a halo. For this reason, it is presumed that an IGZO film formed at room temperature is in an intermediate state that is neither crystalline nor amorphous, and therefore it cannot be concluded that it is in an amorphous state.

[0414] <<Structure of oxide semiconductor>> Note that oxide semiconductors may be classified differently from the above when focusing on their structures. For example, oxide semiconductors are classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0415] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0416] [CAAC-OS] CAAC-OS is an oxide semiconductor having a plurality of crystalline regions, each of which has a c-axis aligned in a specific direction. 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. The crystalline region is a region having periodic atomic arrangement. If the atomic arrangement is considered as a lattice arrangement, the crystalline region is also a region with a uniform lattice arrangement. CAAC-OS has a region in which a plurality of crystalline regions are connected in the ab-plane direction, and the region may have distortion. The distortion refers to a portion in which the direction of the lattice arrangement changes between a region with a uniform lattice arrangement and another region with a uniform lattice arrangement in the region in which the plurality of crystalline regions are connected. In other words, CAAC-OS is an oxide semiconductor having a c-axis aligned and no clear orientation in the ab-plane direction.

[0417] Each of the multiple crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be about several tens of nm.

[0418] In addition, in an In-M-Zn oxide (wherein element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), the CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter, In layer) and a layer containing element M, zinc (Zn), and oxygen (hereinafter, (M, Zn) layer) are stacked. Note that indium and element M are mutually substituted. Thus, the (M, Zn) layer may contain indium. Also, the In layer may contain element M. Note that the In layer may contain Zn. The layered structure is observed as a lattice image in a high-resolution transmission electron microscope (TEM) image, for example.

[0419] When the CAAC-OS film is subjected to structural analysis using, for example, an XRD device, a peak indicating c-axis orientation is detected at or near 2θ=31° in out-of-plane XRD measurement using θ / 2θ scan. Note that the position of the peak indicating c-axis orientation (2θ value) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0420] For example, a plurality of bright points (spots) are observed in the electron diffraction pattern of the CAAC-OS film, and the two spots are observed at positions symmetrical to each other with respect to the spot of the incident electron beam that has passed through the sample (also called the direct spot).

[0421] When the crystal region is observed from the specific direction, the lattice arrangement in 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. The above distortion may have a pentagonal or heptagonal lattice arrangement. In addition, no clear grain boundary can be confirmed in the CAAC-OS even in the vicinity of the distortion. That is, it is found that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is considered to be because the CAAC-OS can tolerate distortion due to the fact that the arrangement of oxygen atoms is not dense in the ab-plane direction and the bond distance between atoms changes due to the substitution of metal atoms.

[0422] A crystal structure in which clear grain boundaries are observed is called a polycrystal. The grain boundaries are likely to become recombination centers and capture carriers, causing a decrease in the on-current of a transistor and a decrease in field effect mobility. Therefore, CAAC-OS in which clear grain boundaries are not observed is one of the crystalline oxides having a crystal structure suitable for a semiconductor layer of a transistor. In order to form a CAAC-OS, a structure containing Zn is preferable. For example, In-Zn oxide and In-Ga-Zn oxide are suitable because they can suppress the occurrence of grain boundaries more than In oxide.

[0423] The CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. In addition, since the crystallinity of an oxide semiconductor can be decreased by the inclusion of impurities or the generation of defects, the CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Therefore, the physical properties of an oxide semiconductor having the CAAC-OS are stable. Therefore, an oxide semiconductor having the CAAC-OS is resistant to heat and has high reliability. In addition, the CAAC-OS is stable against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, the use of the CAAC-OS in an OS transistor can increase the degree of freedom in the manufacturing process.

[0424] [nc-OS] The nc-OS has periodic atomic arrangement in a minute region (for example, a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has minute crystals. Note that the size of the minute crystals is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore the minute crystals are also called nanocrystals. In addition, the nc-OS does not show regularity in crystal orientation between different nanocrystals. Therefore, no orientation is seen in the entire film. Therefore, depending on the analysis method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor. For example, when a structure analysis is performed on an nc-OS film using an XRD device, no peak indicating crystallinity is detected in out-of-plane XRD measurement using θ / 2θ scan. In addition, when an nc-OS film is subjected to electron diffraction (also called selected area electron diffraction) using an electron beam with a probe diameter larger than that of nanocrystals (for example, 50 nm or more), a diffraction pattern like a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter (e.g., 1 nm to 30 nm) that is close to the size of a nanocrystal or smaller than the nanocrystal, an electron diffraction pattern in which multiple spots are observed within a ring-shaped region centered on the direct spot may be obtained.

[0425] [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 void or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. Moreover, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and CAAC-OS.

[0426] <<Oxide semiconductor structure>> Next, the above-mentioned CAC-OS will be described in detail, with reference to its material composition.

[0427] [CAC-OS] CAC-OS is, for example, a material configuration in which elements constituting a metal oxide are unevenly distributed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof. In the following, a state in which one or more metal elements are unevenly distributed in a metal oxide and the regions having the metal elements are mixed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof, is also referred to as a mosaic or patch state.

[0428] Furthermore, CAC-OS is a composite metal oxide in which the material is separated into a first region and a second region, forming a mosaic structure, and the first region is distributed throughout the film (hereinafter, also referred to as a cloud structure). In other words, CAC-OS is a composite metal oxide in which the first region and the second region are mixed together.

[0429] 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.

[0430] 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.

[0431] In addition, there are cases where a clear boundary between the first region and the second region cannot be observed.

[0432] 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.

[0433] CAC-OS can be formed, for example, by a sputtering method under conditions where the substrate is not intentionally heated. When CAC-OS is formed by a sputtering method, any one or more selected from an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as a deposition gas. The lower the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition, the more preferable it is. For example, the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition is preferably 0% or more and less than 30%, and more preferably 0% or more and 10% or less.

[0434] Furthermore, for example, in the case of a CAC-OS of an In-Ga-Zn oxide, EDX mapping obtained using EDX (Energy Dispersive X-ray spectroscopy) can confirm that the CAC-OS has a structure in which a region mainly composed of In (first region) and a region mainly composed of Ga (second region) are unevenly distributed and mixed.

[0435] Here, the first region is a region with higher conductivity than the second region. In other words, the first region exhibits conductivity as a metal oxide when carriers flow through the first region. Therefore, the first region is distributed in a cloud-like shape in the metal oxide, thereby realizing a high field-effect mobility (μ).

[0436] On the other hand, the second region has higher insulating properties than the first region. That is, the second region is distributed in the metal oxide, so that leakage current can be suppressed.

[0437] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act in a complementary manner, giving the CAC-OS a switching function (On / Off function). In other words, CAC-OS has a conductive function in part of the material and an insulating function in part of the material, and the material as a whole functions as a semiconductor. By separating the conductive function from the insulating function, it is possible to maximize both functions. Therefore, by using CAC-OS in a transistor, it is possible to achieve a high on-current (I on ), high field effect mobility (μ), and good switching operation can be achieved.

[0438] In addition, a transistor using CAC-OS has high reliability, making it ideal for various semiconductor devices such as display devices.

[0439] Oxide semiconductors have a variety of structures and each structure has different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS.

[0440] <Transistor Having Oxide Semiconductor> Next, the case where the oxide semiconductor is used for a transistor will be described.

[0441] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0442] For the transistor, an oxide semiconductor having a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 Less than or equal to 1×10 15 cm -3 Less than 1×10, more preferably 13 cm -3 Less than or equal to 1×10 11 cm -3 Less than 1×10, more preferably 10 cm -3 Less than 1 x 10 -9 cm -3 The above is the case. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, an oxide semiconductor having a low impurity concentration and a low density of defect states is referred to as a high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may be referred to as a high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor.

[0443] In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore the density of trap states might also be low.

[0444] In addition, charges trapped in the trap states of an oxide semiconductor take a long time to disappear and may behave as if they are fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0445] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. In order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in a nearby film. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

[0446] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0447] When an oxide semiconductor contains silicon or carbon, which is one of the group 14 elements, defect levels are formed in the oxide semiconductor. For this reason, the concentrations of silicon or carbon in the oxide semiconductor and those near the interface with the oxide semiconductor (concentrations obtained by secondary ion mass spectrometry (SIMS)) are calculated as 2×10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0448] In addition, when an oxide semiconductor contains an alkali metal or an alkaline earth metal, defect levels are formed and carriers are generated in some cases. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal is likely to have normally-on characteristics. For this reason, when the concentration of an alkali metal or an alkaline earth metal in an oxide semiconductor obtained by SIMS is 1×10 18 atoms / cm 3 Less than or equal to 2 x 10 16 atoms / cm 3 To the following:

[0449] Furthermore, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor is likely to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in an oxide semiconductor obtained by SIMS is set to 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than or equal to 1×10 18 atoms / cm 3 Less than 5×10, more preferably 17 atoms / cm 3 To the following:

[0450] Furthermore, hydrogen contained in an oxide semiconductor reacts with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. When hydrogen enters the oxygen vacancy, electrons serving as carriers may be generated. In addition, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons serving as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. For this reason, it is preferable to reduce hydrogen in the oxide semiconductor as much as possible. Specifically, when the hydrogen concentration in an oxide semiconductor measured by SIMS is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5×10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 Make it less than.

[0451] When an oxide semiconductor in which impurities are sufficiently reduced is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0452] This embodiment mode can be combined with other embodiment modes as appropriate.

[0453] (Embodiment 5) In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0454] The electronic device of this embodiment includes the display device of one embodiment of the present invention. For example, the display device of one embodiment of the present invention can be applied to a display portion of an electronic device. The display device of one embodiment of the present invention has a function of detecting light, and therefore can perform biometric authentication or detect a touch operation (contact or proximity) in the display portion. This can improve the functionality, convenience, and the like of the electronic device.

[0455] Examples of electronic devices include electronic devices with relatively large screens, such as television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and audio playback devices.

[0456] The electronic device of this embodiment may have a sensor (including a function to measure force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0457] The electronic device of the present embodiment can have various functions, such as a function of displaying various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function of displaying a calendar, date, time, etc., a function of executing various software (programs), a wireless communication function, a function of reading out a program or data recorded on a recording medium, etc.

[0458] Electronic device 6500 shown in FIG. 21A is a portable information terminal that can be used as a smartphone.

[0459] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508. The display portion 6502 has a touch panel function.

[0460] The display device of one embodiment of the present invention can be applied to the display portion 6502.

[0461] FIG. 21B is a schematic cross-sectional view including the end portion of the housing 6501 on the microphone 6506 side.

[0462] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0463] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by an adhesive layer (not shown).

[0464] In an area outside the display unit 6502, a part of the display panel 6511 is folded back, and the folded back part is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0465] The flexible display of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while suppressing the thickness of the electronic device. In addition, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0466] When the display device of one embodiment of the present invention is used for the display panel 6511, an image can be captured in the display portion 6502. For example, a fingerprint can be captured on the display panel 6511 and fingerprint authentication can be performed.

[0467] The display portion 6502 can have a touch panel function by further including a touch sensor panel 6513. The touch sensor panel 6513 can be of any of various types, such as a capacitive type, a resistive film type, a surface acoustic wave type, an infrared type, an optical type, or a pressure-sensitive type. Alternatively, the display panel 6511 may function as a touch sensor, in which case the touch sensor panel 6513 is not necessarily provided.

[0468] 22A shows an example of a television device. In a television device 7100, a display unit 7000 is incorporated in a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0469] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0470] 22A can be operated using an operation switch provided on the housing 7101 or a separate remote control 7111. Alternatively, a touch sensor may be provided on the display unit 7000, and the television unit 7100 may be operated by touching the display unit 7000 with a finger or the like. The remote control 7111 may have a display unit that displays information output from the remote control 7111. Using an operation key or a touch panel provided on the remote control 7111, it is possible to operate the channel and the volume, and to operate the video displayed on the display unit 7000.

[0471] The television device 7100 includes a receiver and a modem. The receiver can receive general television broadcasts. By connecting to a wired or wireless communication network via the modem, one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers) information communication can be performed.

[0472] 22B shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. A display unit 7000 is incorporated in the housing 7211.

[0473] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0474] 22C and 22D show an example of digital signage.

[0475] 22C includes a housing 7301, a display unit 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, an operation key (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0476] 22D shows a digital signage 7400 attached to a cylindrical pole 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pole 7401.

[0477] 22C and 22D, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0478] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it catches people's attention, which can increase the advertising effect of, for example, advertisements.

[0479] Applying a touch panel to the display unit 7000 is preferable because it not only displays images or videos on the display unit 7000 but also allows the user to intuitively operate it. Furthermore, when used for providing information such as route information or traffic information, usability can be improved by intuitive operation.

[0480] 22C and 22D, it is preferable that the digital signage 7300 or the digital signage 7400 can be linked to an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user via wireless communication. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411. Furthermore, the display on the display unit 7000 can be switched by operating the information terminal 7311 or the information terminal 7411.

[0481] In addition, a game can be executed 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). This allows an unspecified number of users to participate in and enjoy the game at the same time.

[0482] The electronic device shown in Figures 23A to 23F has a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including a function to measure force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 9008, etc.

[0483] The electronic devices shown in Figs. 23A to 23F have various functions. For example, they may have a function of displaying various information (still images, videos, 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. The functions of the electronic devices are not limited to these, and they may have various functions. The electronic devices may have multiple display units. In addition, the electronic devices may have a function of providing a camera or the like in the electronic device, taking still images or videos, and storing them on a recording medium (external or built-in to the camera), a function of displaying the taken images on the display unit, etc.

[0484] The electronic devices shown in FIGS. 23A to 23F will be described in detail below.

[0485] FIG. 23A is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 can be used as, for example, a smartphone. Note that the mobile information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, and the like. The mobile information terminal 9101 can display text and image information on a plurality of surfaces. FIG. 23A shows an example in which three icons 9050 are displayed. Information 9051 shown in a dashed rectangle can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notifications of incoming e-mail, SNS, and phone calls, titles of e-mail and SNS, sender names, date and time, time, remaining battery level, and antenna reception strength. Alternatively, the icon 9050 or the like may be displayed at the position where the information 9051 is displayed.

[0486] 23B is a perspective view showing a mobile information terminal 9102. The mobile information terminal 9102 has a function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053 displayed in a position that can be observed from above the mobile information terminal 9102 while the mobile information terminal 9102 is stored in a breast pocket of a garment. The user can check the display without taking the mobile information terminal 9102 out of the pocket and decide, for example, whether or not to answer a call.

[0487] FIG. 23C is a perspective view showing a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch. The display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free conversation by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and charging with another information terminal through a connection terminal 9006. Note that charging may be performed by wireless power supply.

[0488] 23D to 23F are perspective views showing a foldable mobile information terminal 9201. FIG. 23D is a perspective view of the mobile information terminal 9201 in an unfolded state, FIG. 23F is a perspective view of the mobile information terminal 9201 in a folded state, and FIG. 23E is a perspective view of a state in the middle of changing from one of FIG. 23D and FIG. 23F 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.

[0489] This embodiment mode can be combined with other embodiment modes as appropriate. [Explanation of symbols]

[0490] C1b: capacitance, C1g: capacitance, C1r: capacitance, C2b: capacitance, C2g: capacitance, C2r: capacitance, Cf: capacitance, GL1: wiring, GL2: wiring, M1B: transistor, M1G: transistor, M1R: transistor, M2B: transistor, M2G: transistor, M2R: transistor, M3B: transistor, M3G: transistor, M3R: transistor, M4B: transistor, M4G: transistor, M4R: transistor, M11: transistor, M12: transistor, M13: transistor, M14: transistor, RS: wiring, SE: wiring ,SLB: wiring,SLG: wiring,SLR: wiring,TX: wiring,V0: wiring,VCP: wiring,VPI: wiring,VRS: wiring,WX: wiring,10A: display device,10B: display device,10C: display device,21B: light,21G: light,21R: light,22: light,23: light,24: reflected light,42: transistor,47B: light emitting device,47G: light emitting device,47R: light receiving / emitting device,50A: display device,50B: display device,51: substrate,52: finger,53: layer having light receiving / emitting device,55: layer having transistor,57: layer having light emitting device,59: substrate,10 0A: display device, 100B: display device, 100C: display device, 101: anode, 102: cathode, 103: EL layer, 103a: EL layer, 103b: EL layer, 104: charge generation layer, 112: common layer, 114: common layer, 115: common electrode, 121: hole injection layer, 122: hole transport layer, 122a: hole transport layer, 122b: hole transport layer, 123: light emitting layer, 123-1: light emitting region, 124: electron transport layer, 124-1: region, 124a: electron transport layer, 124b: electron transport layer, 125: electron injection layer, 142: adhesive layer, 143: space, 151: substrate, 152: substrate, 153: base plate, 154: substrate, 155: adhesive layer, 162: display unit, 164: circuit, 165: wiring, 166: conductive layer, 172: FPC, 173: IC, 180: first electrode, 181: hole injection layer, 182: hole transport layer, 182B: hole transport layer, 182G: hole transport layer, 182R: hole transport layer, 183: active layer, 184: electron transport layer, 185: electron injection layer, 186: layer serving as both light-emitting layer and active layer, 189: second electrode, 190: light-emitting device, 190B: light-emitting device, 190G: light-emitting device, 190R·PD: light-receiving / light-emitting device, 191: pixel electrode, 192: buffer layer,192B: buffer layer, 192G: buffer layer, 192R: buffer layer, 193: light-emitting layer, 193B: light-emitting layer, 193G: light-emitting layer, 193R: light-emitting layer, 194: buffer layer, 194B: buffer layer, 194G: buffer layer, 194R: buffer layer, 195: protective layer, 201: transistor, 204: connection portion, 205: transistor, 206: transistor, 207: transistor, 208: transistor, 209: transistor, 210: transistor, 211: insulating layer, 212: insulating layer, 213 : insulating layer, 214: insulating layer, 215: insulating layer, 216: partition wall, 217: partition wall, 218: insulating layer, 221: conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 225: insulating layer, 228: region, 231: semiconductor layer, 231i: channel formation region, 231n: low resistance region, 242: connection layer, 6500: electronic device, 6501: housing, 6502: display unit, 6503: power button, 6504: button, 6505: speaker, 6506: microphone, 6507: camera, 6508: light source, 6510: protection Component, 6511: display panel, 6512: optical component, 6513: touch sensor panel, 6515: FPC, 6516: IC, 6517: printed circuit board, 6518: battery, 7000: display unit, 7100: television device, 7101: housing, 7103: stand, 7111: remote control device, 7200: notebook personal computer, 7211: housing, 7212: keyboard, 7213: pointing device, 7214: external connection port, 7300: digital signage, 7301: housing Body, 7303: speaker, 7311: information terminal, 7400: digital signage, 7401: pillar, 7411: information terminal, 9000: housing, 9001: display unit, 9003: speaker, 9005: operation key, 9006: connection terminal, 9007: sensor, 9008: microphone, 9050: icon, 9051: information, 9052: information, 9053: information, 9054: information, 9055: hinge, 9101: portable information terminal, 9102: portable information terminal, 9200: portable information terminal, 9201: portable information terminal,< / n> < / n> < / m> < / n> < / n> < / m> < / m> < / n> < / m> < / n> < / n> < / n> < / n> < / n> < / n> < / n> < / n> < / m> < / n> < / n> < / n> < / n> < / n> < / n> < / n> < / n> < / n> < / n> < / n> < / n> < / n>

Claims

1. a pixel, a first wiring, a second wiring, and a third wiring; The pixel has a first subpixel, the first subpixel includes first to eighth transistors, a first capacitance, and a light emitting / receiving device; one of a source and a drain of the first transistor is electrically connected to the first wiring, and the other of the source and the drain is electrically connected to a gate of the second transistor and one electrode of the first capacitor; one electrode of the light emitting and receiving device is electrically connected to one of a source and a drain of the second transistor, one of a source and a drain of the third transistor, and one of a source and a drain of the fifth transistor; one of a source and a drain of the fourth transistor is electrically connected to the second wiring, and the other of the source and drain of the fourth transistor is electrically connected to the other of the source and drain of the third transistor and the other electrode of the first capacitor; the other of the source and the drain of the fifth transistor is electrically connected to one of the source and the drain of the sixth transistor and to a gate of the seventh transistor; one of a source and a drain of the seventh transistor is electrically connected to one of a source and a drain of the eighth transistor; the other of the source and the drain of the eighth transistor is electrically connected to the third wiring; the light emitting and receiving device has a first light emitting layer and an active layer between one electrode of the light emitting and receiving device and the other electrode of the light emitting and receiving device; the first light emitting layer has a region in contact with the active layer, the light receiving and emitting device has a function of emitting light of a first color and a function of receiving light of a second color; A display device, wherein the second color light has a shorter wavelength than the first color light.

2. In claim 1, a first data potential is supplied to the first wiring; a second data potential is supplied to the second wiring during a first period, and a reset potential is supplied to the second wiring during a second period; A display device, wherein a potential corresponding to the charge generated in the light emitting and receiving device is supplied to the third wiring.

3. In claim 1 or 2, Further, the semiconductor device has fourth to eighth wirings, a gate of the first transistor and a gate of the third transistor are electrically connected to the fourth wiring; a gate of the fourth transistor is electrically connected to the fifth wiring; a gate of the fifth transistor is electrically connected to the sixth wiring; a gate of the sixth transistor is electrically connected to the seventh wiring; a gate of the eighth transistor is electrically connected to the eighth wiring.

4. In any one of claims 1 to 3, The first subpixel further includes a second capacitance. one electrode of the second capacitor is electrically connected to the other of the source and the drain of the first transistor, the gate of the second transistor, and one electrode of the first capacitor; A display device, wherein the other electrode of the second capacitor is electrically connected to one electrode of the light receiving and emitting device, one of the source and drain of the second transistor, one of the source and drain of the third transistor, and one of the source and drain of the fifth transistor.

5. In any one of claims 1 to 4, Further, a ninth wiring is provided, The pixel further comprises a second subpixel, the second subpixel includes ninth to eleventh transistors and a light emitting device; one of a source and a drain of the ninth transistor is electrically connected to the ninth wiring, and the other is electrically connected to a gate of the tenth transistor; one electrode of the light emitting device is electrically connected to one of a source and a drain of the tenth transistor and one of a source and a drain of the eleventh transistor; The light emitting device is capable of emitting light of the second color.

6. In claim 5, the second subpixel further includes a twelfth transistor; one of a source and a drain of the twelfth transistor is electrically connected to the second wiring, and the other of the source and drain of the eleventh transistor is electrically connected to the other of the source and drain of the eleventh transistor.

7. In claim 5, the other of the source and the drain of the eleventh transistor is electrically connected to the second wiring.

8. In any one of claims 5 to 7, A display device, wherein the light emitting and receiving device and the light emitting device are provided on the same surface.

9. In any one of claims 5 to 8, the light emitting device comprises a hole injection layer, a second light emitting layer, and an electron transport layer; the hole injection layer comprises a first compound and a second compound; The electron transport layer comprises an electron transport material, the first compound has an electron accepting property for the second compound, the HOMO level of the second compound is −5.7 eV or more and −5.4 eV or less; The electron transporting material has a HOMO level of −6.0 eV or more and an electron mobility of 1×10 at a square root of an electric field strength [V / cm] of 600. －７ cm ２ / Vs or more 5×10 －５ cm ２ / Vs or less.

10. In any one of claims 5 to 8, the light emitting device comprises a second light emitting layer and an electron transport layer; The electron transport layer includes an electron transport material and a first substance, the first substance is a metal, a metal salt, a metal oxide, or an organometallic complex; the electron transport layer has a first region and a second region; A display device, wherein the first region and the second region have mutually different concentrations of the first substance.

11. In any one of claims 1 to 10, Further, the substrate has flexibility, The first to eighth transistors are located on the substrate.

12. A display module comprising the display device according to any one of claims 1 to 11 and a connector or an integrated circuit.

13. A display module according to claim 12; An electronic device having at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button.

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