Semiconductor Devices

Abstract

To provide an inexpensive display device with a narrow frame.SOLUTION: A display device comprises a first pixel having a light emitting device, a second pixel having a light receiving device, and a readout circuit for reading out information acquired by the second pixel. The readout circuit has a first circuit included in a mounted IC chip, and a second circuit monolithically formed on a substrate on which a pixel circuit is formed. With this configuration, the circuit corresponding to the second circuit can be omitted from the IC chip, so that the IC chip can be miniaturized.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect of the present invention relates to a display device.

[0002] It should be noted that one aspect of the present invention is not limited to the above-mentioned technical field. Examples of technical fields of one aspect of the present invention include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), methods for driving them, or methods for manufacturing them. [Background technology]

[0003] In recent years, display devices have been applied to a wide variety of uses. Examples of large-scale display devices include home television systems, digital signage, and PID (Public Information Display). Display devices are also widely used in smartphones and tablet devices equipped with touch panels.

[0004] As a display device, light-emitting devices (also called light-emitting elements) have been developed. Light-emitting devices that utilize the electroluminescence (EL) phenomenon (also called EL devices or EL elements) have features such as being easy to make thin and light, being able to respond quickly to input signals, and being able to be driven using a DC constant voltage power supply.

[0005] Patent Document 1 discloses an example of a display device using an organic EL element. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2002-324673 [Overview of the project] [Problems that the invention aims to solve]

[0007] By equipping pixels with light-receiving devices, a display device can be given imaging capabilities. In a display device with imaging capabilities, images such as fingerprints or palm prints, applicable to personal authentication, can be obtained by touching a finger or palm to the panel surface. Furthermore, the imaging capabilities of the light-receiving device can also be used as a touch sensor.

[0008] Here, the display device is provided with drive circuits for driving pixels having light-emitting devices and pixels having light-receiving devices. The display device is also provided with readout circuits for reading data from pixels having light-receiving devices.

[0009] IC chips are used in some or all of these drive and read circuits. These IC chips are mounted on the bezel of the substrate on which the pixel circuits are formed, using technologies such as COG (Chip On Glass), COF (Chip On Film), or TCP (Tape Carrier Package).

[0010] As the number of IC chips implemented increases, the manufacturing cost of the display device also increases. Furthermore, it hinders the creation of narrower bezels. To address these challenges, it is desirable to reduce the number of IC chips by forming part of the drive and read circuits monolithically on the same substrate as the pixel circuit, or to miniaturize the IC chips themselves.

[0011] Therefore, one aspect of the present invention aims to provide an inexpensive display device with a narrow bezel. Alternatively, it aims to provide a display device in which part of the readout circuit is formed in a monolithic type. Alternatively, it aims to provide a display device with a narrow bezel. Alternatively, it aims to provide a display device with an authentication function. Alternatively, it aims to provide a highly reliable display device. Alternatively, it aims to provide an electronic device having the above-mentioned display device.

[0012] Furthermore, the description of these problems does not preclude the existence of other problems. One aspect of the present invention does not necessarily have to solve all of these problems. It is possible to extract other problems from the description in the specification, drawings, and claims. [Means for solving the problem]

[0013] One aspect of the present invention is a display device having a first pixel circuit and an A / D conversion circuit, wherein the A / D conversion circuit has a first circuit, the first pixel circuit and the first circuit are formed on the same substrate, the first circuit has a resistive voltage divider circuit, the resistive voltage divider circuit has a plurality of transistors whose drains and first gates are electrically connected, the transistors have a metal oxide in the semiconductor layer, and the transistors have a channel forming region provided along the side surface of the insulating layer.

[0014] Multiple transistors can be connected in series such that, in two adjacent transistors, the source of one transistor is electrically connected to the drain and first gate of the other transistor.

[0015] Multiple transistors each have a second gate, and in the first and second transistors included in the multiple transistors, the source potential of the second transistor is lower than the source potential of the first transistor, and the second gate of the first transistor can be electrically connected to the source of the second transistor.

[0016] The substrate has a first conductive layer, an insulating layer, and a second conductive layer, and openings can be provided in the insulating layer and the second conductive layer so as to reach the first conductive layer.

[0017] A transistor having a channel-forming region along the side surface of an insulating layer may have a semiconductor layer having a metal oxide that covers an opening, a second insulating layer provided on the semiconductor layer having a metal oxide and a second conductive layer that covers a recess originating from the opening, and a third conductive layer provided on the second insulating layer that covers a recess originating from the opening.

[0018] An offset region may be provided between the channel and the drain of the semiconductor layer in a transistor having a channel-forming region along the side surface of the insulating layer.

[0019] The A / D conversion circuit has a second circuit, which is provided on an IC chip mounted on a substrate, and the second circuit can be electrically connected to the first circuit.

[0020] The first pixel circuit has a light-receiving device. The display device also has a second pixel circuit, and the second pixel circuit has a light-emitting device.

[0021] Another aspect of the present invention is an electronic device having the above-mentioned display device, which acquires a fingerprint image with a first pixel circuit and performs fingerprint authentication. [Effects of the Invention]

[0022] According to one aspect of the present invention, a display device with a narrow bezel and low cost can be provided. Alternatively, a display device in which part of the reading circuit is formed in a monolithic type can be provided. Alternatively, a display device with a narrow bezel can be provided. Alternatively, a display device having an authentication function can be provided. Alternatively, a highly reliable display device can be provided. Alternatively, an electronic device having the above-mentioned display device can be provided.

[0023] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description, drawings, and claims. [Brief explanation of the drawing]

[0024] [Figure 1] Figure 1 is a block diagram illustrating the display device. [Figure 2] Figure 2 is a diagram illustrating an A / D conversion circuit. [Figure 3] Figure 3 is a diagram illustrating an A / D conversion circuit. [Figure 4] Figure 4 is a diagram illustrating an A / D conversion circuit. [Figure 5] Figure 5(A) illustrates a resistive voltage divider circuit. Figure 5(B) illustrates the potential supplied to the back gate of a transistor. Figure 5(C) illustrates the threshold voltage shift of a transistor. [Figure 6] Figures 6(A) and 6(B) illustrate a resistive voltage divider circuit. [Figure 7] Figures 7(A) and 7(B) illustrate a vertical transistor. [Figure 8] Figures 8(A) and 8(B) illustrate a vertical transistor. [Figure 9] Figures 9(A) and 9(B) illustrate the diode and series connections of transistors. [Figure 10] Figures 10(A) and 10(B) illustrate diode and series connections of transistors. [Figure 11] Figures 11(A) and 11(C) illustrate the diode and series connections of a transistor. Figure 11(B) illustrates the wiring connected to the back gate of a transistor. [Figure 12] Figures 12(A) and 12(C) illustrate the diode and series connections of a transistor. Figure 12(B) illustrates the wiring connected to the back gate of a transistor. [Figure 13] Figures 13(A) through 13(C) illustrate the offset region of a transistor. [Figure 14]Figures 14(A) to 14(C) illustrate a pixel circuit having a light-emitting device. Figure 14(D) illustrates a pixel circuit having a light-receiving device. [Figure 15] Figure 15(A) is a top view illustrating an example of a display device. Figures 15(B) and 15(C) are cross-sectional views illustrating an example of a display device. [Figure 16] Figure 16 is a cross-sectional view illustrating the elements of the display device. [Figure 17] Figures 17(A) to 17(K) illustrate an example of a pixel. [Figure 18] Figure 18 is a perspective view illustrating an example of a display device. [Figure 19] Figure 19(A) is a cross-sectional view illustrating an example of a display device. Figures 19(B) and 19(C) are cross-sectional views illustrating an example of a transistor. [Figure 20] Figures 20(A) to 20(F) illustrate examples of the configuration of a light-emitting device. [Figure 21] Figures 21(A) to 21(C) illustrate examples of the configuration of a light-emitting device. [Figure 22] Figures 22(A) and 22(B) illustrate examples of the configuration of a light-receiving device. Figures 22(C) through 22(E) illustrate examples of the configuration of a display device. [Figure 23] Figures 23(A) through 23(F) illustrate an example of an electronic device. [Figure 24] Figures 24(A) to 24(G) illustrate an example of an electronic device. [Modes for carrying out the invention]

[0025] Embodiments will be described in detail with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the invention. Therefore, the present invention is not to be interpreted as being limited to the descriptions of the embodiments shown below. In the configuration of the invention described below, the same reference numerals are used in common between different drawings for the same parts or parts having similar functions, and repeated descriptions may be omitted. In addition, hatching of the same elements constituting the figures may be omitted or changed as appropriate between different drawings.

[0026] Furthermore, even if an element is shown as a single element in a circuit diagram, it may be composed of multiple elements as long as there is no functional disadvantage. For example, multiple transistors that act as switches may be connected in series or parallel. Also, a capacitor may be divided and placed in multiple locations.

[0027] Furthermore, a single conductor may have multiple functions, such as wiring, electrodes, and terminals, and in this specification, multiple designations may be used for the same element. Also, even if elements are shown as directly connected in a circuit diagram, they may actually be connected via one or more conductors, and in this specification, such configurations are included in the category of direct connection.

[0028] (Embodiment 1) In this embodiment, a display device according to one aspect of the present invention will be described with reference to the drawings.

[0029] One aspect of the present invention is a display device having a first pixel having a light-emitting device, a second pixel having a light-receiving device, and a readout circuit for reading information acquired by the second pixel. The readout circuit has a first circuit on a mounted IC chip and a second circuit formed monolithically on a substrate on which the pixel circuit is formed.

[0030] The pixel circuit and the second circuit each have transistors with a metal oxide in the semiconductor layer. Furthermore, the transistors in the second circuit have a structure that is easier to miniaturize than the transistors in the pixel circuit. Therefore, the area occupied by the second circuit can be reduced, and it does not hinder the narrowing of the bezel.

[0031] This configuration allows for the elimination of a second circuit from the IC chip, thus enabling miniaturization of the IC chip. Consequently, the number of IC chips that can be extracted from a single semiconductor wafer during the manufacturing process can be increased, reducing the price of the IC chips. In other words, the manufacturing cost of the display device can be reduced. Furthermore, the area required for mounting the IC chip can be reduced, allowing for a narrower bezel on the display device.

[0032] Figure 1 is a block diagram illustrating a display device according to one aspect of the present invention. The display device 30 includes a pixel array 13, a circuit 14, a circuit 15, a circuit 16, and a circuit 20. The pixel array 13 has pixels 10 arranged in the column and row directions.

[0033] Pixel 10 may have sub-pixels 11 and 12. For example, sub-pixel 11 has the function of emitting light for display. Sub-pixel 12 has the function of detecting light irradiated onto the display device 30. Note that there may be multiple sub-pixels 11 and 12 in a single pixel 10.

[0034] In this specification, the smallest unit in which an independent operation takes place within a single "pixel" is conveniently defined as a "sub-pixel" for explanation purposes. However, "pixel" may be replaced with "region," and "sub-pixel" may be replaced with "pixel."

[0035] The sub-pixel 11 has a light-emitting device that emits visible light. Preferably, an EL element such as an OLED (Organic Light Emitting Diode) or QLED (Quantum-dot Light Emitting Diode) is used as the light-emitting device. Examples of light-emitting materials for EL elements include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and inorganic compounds (such as quantum dot materials). Alternatively, an LED such as a microLED (Light Emitting Diode) can be used as the light-emitting device.

[0036] The sub-pixel 12 has a photodetector that is sensitive to visible light or infrared light. For example, near-infrared light can be used as the infrared light. The photodetector can be a photoelectric conversion element that detects incident light and generates an electric charge. In the photodetector, the amount of charge generated is determined based on the amount of incident light. For example, a pn-type or pin-type photodiode can be used as the photodetector.

[0037] As the light-receiving device, it is preferable to use an organic photodiode having an organic compound in its photoelectric conversion layer. Organic photodiodes are easy to make thin, light, and large in area. Also, because they offer a high degree of freedom in shape and design, they can be applied to various display devices. Alternatively, a photodiode using crystalline silicon (single-crystal silicon, polycrystalline silicon, microcrystalline silicon, etc.) can also be used as the light-receiving device.

[0038] In one aspect of the present invention, an organic EL element is used as the light-emitting device, and an organic photodiode is used as the light-receiving device. The organic photodiode may have a configuration that shares elements with the organic EL element. Therefore, the light-receiving device can be incorporated into the display device 30 without significantly increasing the manufacturing process. For example, the photoelectric conversion layer of the light-receiving device and the light-emitting layer of the light-emitting device may be manufactured separately, while the remaining layers may include the same configuration for both the light-emitting and light-receiving devices.

[0039] Circuits 14 and 15 are driver circuits for driving the sub-pixels 11. Circuit 14 can function as a source driver, and circuit 15 can function as a gate driver. Circuits 14 and 15 can be, for example, shift register circuits.

[0040] Circuit 16 is a driver circuit for driving the sub-pixels 12. Circuit 16 can also function as a low driver. Circuit 16 and circuit 22, which will be described later, can be replaced with, for example, a shift register circuit or a decoder circuit.

[0041] Circuits 14, 15, and 16 can be provided by mounting IC chips on the substrate on which the pixels 10 are formed. Alternatively, one or more of circuits 14, 15, and 16, or a portion of the circuits constituting circuits 14, 15, and 16, can be formed monolithically on the substrate on which the pixels 10 are formed.

[0042] Circuit 20 is a data readout circuit for the output of sub-pixels 12. Circuit 20 includes a correlated double sampling (CDS) circuit 17 that performs correlated double sampling on the output data of sub-pixels 12, an analog-to-digital (A / D) conversion circuit 21 that converts the analog data output by the CDS circuit 17 into digital data, and a circuit 22 that functions as a column driver that outputs the generated digital data column by column to the outside.

[0043] The circuit 20 can be configured by combining the circuit of an IC chip mounted on the substrate on which the pixels 10 are formed with a monolithic circuit. Next, one embodiment of the present invention in which a part of the A / D conversion circuit 21 is formed in a monolithic manner will be described.

[0044] Figure 2 illustrates a conventional example of a flash-type A / D conversion circuit that can be used as the A / D conversion circuit 21.

[0045] The A / D conversion circuit 21 includes a circuit 18 corresponding to a voltage generation circuit, and a circuit 19 that has a comparator 23 and an encoder 24 and outputs 2-bit data in parallel. The circuit 19 receives the data (V) output from the CDS circuit 17. dat ) and reference voltage (V) in circuit 18 ref The voltage obtained by voltage division is compared with the voltage obtained by comparator 23, and n bits (corresponding to the number of gradations) of digital data can be output to circuit 22 according to the output of the comparator.

[0046] Here, the circuit 18 shown in Figure 2 is a resistor string (resistive voltage divider circuit), and resistor R(1) to resistor R(2) n Up to +1), the configuration consists of resistors connected in series for each gradation. Here, for 8-bit gradation, there are 257 resistors, and for 10-bit gradation, there are 1025 resistors.

[0047] Considering high-speed operation, the A / D conversion circuit 21, which has circuit 18, needs to be provided in quantities equal to the number of rows in the pixel array 13. In other words, if circuit 18 is provided inside the IC chip, the area it occupies will be very large. Conversely, if circuit 18 can be provided outside the IC chip, the area of ​​the IC chip can be reduced, and the price of the IC chip can be lowered. That is, the manufacturing cost of the display device can be reduced.

[0048] Therefore, in one aspect of the present invention, the circuit 18 is formed monolithically on the substrate on which the pixel circuit is formed. The CDS circuit 17 can also be formed monolithically.

[0049] Figure 3 illustrates an A / D conversion circuit 21 according to one embodiment of the present invention. When forming the circuit 18 in a monolithic form, it is possible to use thin-film semiconductors as resistive elements, but it is difficult to manufacture them so that the resistance values ​​are uniform across a very large number of resistive elements. Furthermore, if the resistance of the thin-film semiconductor cannot be sufficiently reduced, the occupied area will become large.

[0050] Therefore, in one aspect of the present invention, a diode-connected transistor in which the drain and gate are electrically connected is used instead of a resistive element. Furthermore, an n-type vertical transistor is used as the transistor.

[0051] A vertical transistor is a transistor in which a channel formation region is provided in a semiconductor layer formed along the side of an insulating layer, and the channel length can be determined by the thickness of the insulating layer. Because vertical transistors can be formed by overlapping either the source electrode or the drain electrode with the gate electrode, their size can be reduced and the area of ​​the resistor string can be reduced.

[0052] The semiconductor layer of the vertical transistor can be made of polycrystalline silicon, amorphous silicon, or a metal oxide. In particular, it is preferable to use a metal oxide, which does not require a crystallization process. In this embodiment, a vertical transistor using a metal oxide for the semiconductor layer is used.

[0053] The structure of the transistor that can be used in circuit 18 is not particularly limited. For example, planar transistors, finned transistors, staggered transistors, inverse staggered transistors, etc., can be used. Furthermore, either a top-gate or bottom-gate transistor structure may be used.

[0054] A diode-connected n-type transistor has a threshold voltage (V thBy applying a voltage above 250° to the gate, a current flows in proportion to the voltage (drain voltage and gate voltage). Therefore, it can be used as a resistor.

[0055] In the circuit configuration 18 shown in Figure 3, the desired resistor is a transistor (Tr(1) to Tr(2) n To operate (+1)), the transistor's structure and constituent materials should be appropriately selected so that its mobility, threshold voltage, and on-current are suitable.

[0056] Furthermore, in order to obtain the desired resistance value, as shown in Figure 4, transistors (Tr(1) to Tr(2) n A configuration in which a back gate is provided at +1)) is also possible. The back gate of each transistor is configured to have a potential smaller than the source potential of the same transistor, that is, a negative potential is applied when the source potential is 0V.

[0057] In a transistor, the term "back gate" refers to the other gate in a transistor with two gates, when one gate is called the "front gate." Furthermore, in a transistor with two gates, the front gate and back gate may be used reversibly. Also, one of the front gates and the other back gate may be called the "first gate," and the other the "second gate."

[0058] To apply a negative potential to the back gate, for example, as shown in Figure 4, the source of transistor Tr(2) can be electrically connected to the back gate of transistor Tr(1). This configuration eliminates the need for a negative potential generation circuit.

[0059] As shown in Figure 5(A), in a resistive voltage divider circuit, the voltage between resistor R(2) and resistor R(3) is (V OUT2 ) is the voltage (V) between resistor R(1) and resistor R(2). OUT1 It becomes smaller than ).

[0060] Here, as shown in FIG. 5(B), when the resistor is replaced with a transistor, V OUT1 corresponds to the source potential (V S1 ) of the transistor Tr(1), and V OUT2 corresponds to the source potential (V S2 ) of the transistor Tr(2).

[0061] From FIGS. 5(A) and (B), V OUT2 < V OUT1 , and since the source potential (V OUT2 ) of the transistor Tr(2) becomes the back gate potential (V BG1 ) of the transistor Tr(1), V BG1 < V S1 . That is, the back gate potential (V BG1 ) of the transistor Tr(1) becomes negative with respect to the source potential (V S1 ).

[0062] When a negative potential is applied to the back gate of a diode-connected n-type transistor, a high voltage needs to be applied to the gate to generate a channel. In other words, the threshold voltage (V th ) shifts in the positive direction. Therefore, as shown in the I d -V d (V g ) characteristics of FIG. 5(C), in the transistor Tr(1), V BG1 = V S1 is higher than V BG1 < V S1 . Increasing V th is equivalent to increasing the resistance value.

[0063] Note that, similar to the form in which the back gate of the transistor Tr(1) is connected to the source of the transistor Tr(2), the back gate of the transistor Tr(2 n ) is connected to the source of the transistor Tr(2 n +1).

[0064] At this time, the transistor Tr(2 n ​​To make the resistor (+1) the same as other transistors, use the transistor Tr(2 n A next-stage transistor is needed to generate the potential applied to the back gate of (+1). However, it is not appropriate to have more transistors than are required for grayscale control. Therefore, transistor Tr(2 n The back gate (+1) has an appropriate potential V b It is preferable to input this information from an external source.

[0065] Note that transistor Tr(2 n +2) is a resistor that does not contribute to gradation, so a back gate is not necessary in Figure 4, but a back gate may be provided. In this case, transistor Tr(2 n Similar to +1), the transistor Tr(2 n The back gate of (+2) can be supplied with an appropriate potential from an external source.

[0066] Furthermore, while the circuit 18 shown in Figure 4 shows a configuration in which the back gate of transistor Tr(1) is connected to the source of transistor Tr(2), the circuit is not limited to this configuration. For example, as shown in Figure 6(A), the back gate of transistor Tr(1) may be connected to the source of transistor Tr(3). In this case, the potential (V) of the back gate of transistor Tr(1) BG1 ) is the source potential of transistor Tr(3), V OUT3 It will become.

[0067] In the configuration shown in Figure 6(A), the source potential of the x-th transistor Tr(x) connected in series is V OUTx The potential of the back gate is V BGx When V BGx =V OUTx+2 This is the result. Also, V BGx =V OUTx+y In this case, y may be set to 3 or greater. The value of y can be appropriately set to a value smaller than 1 / 4, preferably 1 / 8, more preferably 1 / 16, and even more preferably 1 / 32 of the number of gradations, so that the transistor has an appropriate resistance.

[0068] Furthermore, while we have so far illustrated and explained a diode connection in which the front gate and drain of a transistor are electrically connected, a diode connection in which the back gate and drain of a transistor are electrically connected may also be used. Figure 6(B) shows an example in which the back gate and drain of a transistor are electrically connected.

[0069] In the configuration shown in Figure 6(B), which is the same as in Figure 6(A), the source potential of the x-th transistor Tr(x) connected in series is V OUTx The potential of the front gate is V FGx When V FGx =V OUTx+2 This is the result.

[0070] By manufacturing a display device using the above-described embodiment of the present invention, the circuit corresponding to the second circuit can be omitted from the IC chip, thereby enabling miniaturization of the IC chip. Consequently, the price of the IC chip can be reduced, and manufacturing costs can be lowered. Furthermore, the area required for mounting the IC chip can be reduced, allowing for a narrower bezel on the display device.

[0071] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0072] (Embodiment 2) This embodiment describes a vertical transistor that can be used in the circuit 18 shown in Embodiment 1. In this embodiment, the basic structure of the vertical transistor is described, while the configuration of diode connections and electrical connections between transistors will be described in Embodiment 3.

[0073] Figures 7(A) and 7(B) illustrate a vertical transistor. Figure 7(A) is a top view. Figure 7(B) is a cross-sectional perspective view showing the depth direction of region d, which is indicated by hatching in Figure 7(A). For clarity, some elements are omitted from the illustration in Figures 7(A) and (B).

[0074] A vertical transistor, transistor 100T, can be mounted on a substrate 102. Transistor 100T has a conductive layer 104, a conductive layer 104e, an insulating layer 106, a semiconductor layer 108, a conductive layer 112a, and a conductive layer 112b. Conductive layer 104 is a gate wiring and is electrically connected to conductive layer 104e, which functions as a gate electrode. A portion of the insulating layer 106 functions as a gate insulating layer. Conductive layer 112a functions as either a source electrode or a drain electrode. Conductive layer 112b functions as either a source electrode or a drain electrode.

[0075] Within the semiconductor layer 108, the entire region overlapping with the gate electrode via the gate insulating layer between the source electrode and the drain electrode functions as a channel formation region. Furthermore, within the semiconductor layer 108, the region in contact with the source electrode functions as the source region, and the region in contact with the drain electrode functions as the drain region.

[0076] A conductive layer 112a is provided on the substrate 102, an insulating layer 107 is provided on the conductive layer 112a, and a conductive layer 112b is provided on the insulating layer 107. The insulating layer 107 can be, for example, three layers: insulating layer 107a, insulating layer 107b, and insulating layer 107c, and has a region sandwiched between the conductive layers 112a and 112b. The conductive layer 112a has a region that overlaps with the conductive layer 112b via the insulating layer 107. The insulating layer 107 and the conductive layer 112b have an opening 141 that reaches the conductive layer 112a.

[0077] The conductive layer 112a and the conductive layer 112b may each have a laminated structure. Figure 7(B), etc., shows an example in which the conductive layer 112a has a laminated structure of conductive layer 112a_1 and conductive layer 112a_2. In Figure 7(B), there is a region on conductive layer 112a_1 in which conductive layer 112a_2 is not provided, and this region is in contact with the semiconductor layer 108, but it is also possible to have a configuration in which conductive layer 112a_2 and semiconductor layer 108 are in contact. Furthermore, it is also possible to have a configuration in which conductive layer 112a_2 is not provided.

[0078] The top surface shape of the opening 141 can be, for example, circular or elliptical. By making the top surface shape of the opening 141 circular, the processing accuracy when forming the opening 141 can be improved, and a fine-sized opening 141 can be formed. Alternatively, the top surface shape of the opening 141 may be a polygon such as a triangle, quadrilateral (including rectangles, rhombuses, and squares), or a polygon with rounded corners. The opening 141 can be formed, for example, using a resist mask.

[0079] The semiconductor layer 108 is provided so as to cover the inner wall and bottom of the opening 141. The semiconductor layer 108 has regions that are in contact with the upper and side surfaces of the conductive layer 112b, the side surfaces of the insulating layer 107, and the upper surface of the conductive layer 112a. The semiconductor layer 108 is electrically connected to the conductive layer 112a through the opening 141. The semiconductor layer 108 has a shape that conforms to the shape of the upper and side surfaces of the conductive layer 112b, the side surfaces of the insulating layer 107, and the upper surface of the conductive layer 112a.

[0080] Although Figure 7(B), etc., shows the semiconductor layer 108 as a single layer structure, the present invention is not limited to this. The semiconductor layer 108 may be a stacked structure of two or more layers.

[0081] The insulating layer 106, which functions as the gate insulating layer of transistor 100T, is provided on the semiconductor layer 108, the conductive layer 112b, and the insulating layer 107 so as to cover the recess derived from the opening 141.

[0082] The conductive layer 104e of transistor 100T is provided on the insulating layer 106 so as to cover a recess originating from the opening 141. Here, it is preferable that an insulating layer (not shown) is provided on both the conductive layer 104e and the insulating layer 106. An opening reaching the conductive layer 104e is provided in the insulating layer, and at this opening, the conductive layer 104, which functions as gate wiring, and the conductive layer 104e are electrically connected.

[0083] At the opening 141, the conductive layer 104e has a region that overlaps with the semiconductor layer 108 via the insulating layer 106. The conductive layer 104e also has a region that overlaps with the conductive layer 112a via the insulating layer 106 and the semiconductor layer 108, and a region that overlaps with the conductive layer 112b. Preferably, the conductive layer 104e covers the end of the conductive layer 112b on the opening 141 side. With this configuration, the entire region of the semiconductor layer 108 that overlaps with the gate electrode via the gate insulating layer between the source electrode and the drain electrode can function as a channel-forming region.

[0084] Transistor 100T is a so-called top-gate type transistor, having its gate electrode above semiconductor layer 108. Furthermore, since the lower surface of semiconductor layer 108 is in contact with the source electrode or drain electrode, it can be described as a TGBC (Top Gate Bottom Contact) type transistor.

[0085] Conductive layers 112a, 112b, and 104 can each function as wiring, and the transistor 100T can be placed in the region where these wirings overlap. In other words, in a circuit having the transistor 100T and the wiring, the area occupied by the transistor 100T and the wiring can be reduced. Therefore, the area occupied by the circuit can be reduced.

[0086] In a transistor according to one aspect of the present invention, the conductive layers 112a, 112b, and 104, which function as wiring, can each be provided by processing different conductive films. Therefore, one or more other conductive layers can be placed on top of any of the conductive layers, which increases the freedom of layout and reduces the circuit's occupied area.

[0087] Next, the channel length and channel width of transistor 100T will be described. In semiconductor layer 108, the region in contact with conductive layer 112a functions as either the source region or the drain region, the region in contact with conductive layer 112b functions as either the source region or the drain region, and the region between the source region and the drain region functions as the channel formation region.

[0088] The channel length of transistor 100T is the distance between the source region and the drain region. In Figure 7(B), the channel length L100 of transistor 100T is shown by a dashed double arrow. In a cross-sectional view, the channel length L100 is the distance between the edge of the region where semiconductor layer 108 and conductive layer 112a are in contact and the edge of the region where semiconductor layer 108 and conductive layer 112b are in contact.

[0089] In other words, the channel length L100 is determined by the thickness of the insulating layer 107 and the angle between the side surface of the insulating layer 107 on the opening 141 side and the upper surface of the conductive layer 112a, and is not affected by the performance of the exposure apparatus used to fabricate the transistor. Therefore, the channel length L100 can be set to a value smaller than the limiting resolution of the exposure apparatus, making it possible to realize transistors of a very small size.

[0090] By reducing the channel length L100, the on-current of transistor 100T can be increased. Using transistor 100T allows for the creation of high-speed circuits. Furthermore, the transistor can be miniaturized, reducing the circuit's footprint.

[0091] In addition, while Figure 7(B), etc., shows a configuration in which the shape of the side surface of the insulating layer 107 on the side of the opening 141 is straight in a cross-sectional view, the present invention is not limited to this. In a cross-sectional view, the shape of the side surface of the insulating layer 107 on the side of the opening 141 may be curved, and the side surface may have both a straight region and a curved region.

[0092] The channel width of transistor 100T is the width of the source region or the drain region in a direction perpendicular to the channel length. In other words, the channel width is the width of the region where semiconductor layer 108 and conductive layer 112a are in contact, or the width of the region where semiconductor layer 108 and conductive layer 112b are in contact, in a direction perpendicular to the channel length. Here, the channel width of transistor 100T is described as the width of the region where semiconductor layer 108 and conductive layer 112b are in contact, in a direction perpendicular to the channel length. In Figure 7(B), the channel width W100 of transistor 100T is shown by a solid double arrow. The channel width W100 is the length of the lower edge of conductive layer 112b on the opening 141 side when viewed from above.

[0093] The channel width W100 is determined by the shape of the top surface of the opening 141. If the top surface of the opening 141 is circular, and the diameter of the opening 141 is D141, and the thickness of the conductive layer 112b can be ignored, then the channel width W100 can be calculated as "D141 × π".

[0094] In other words, transistor 100T can be described as a transistor with a large channel width relative to its occupied area. By increasing the channel width W100, the on-current of transistor 100T can be increased, making it possible to create circuits capable of high-speed operation.

[0095] Figures 8(A) and 8(B) illustrate an example in which a back gate is added to the configuration shown in Figures 7(A) and 7(B). The conductive layer 115, which acts as the back gate electrode, is provided so as to be embedded in the insulating layer 107 (insulating layers 107a and 107c), and a portion of the insulating layer 107c provided between the semiconductor layer 108 and the conductive layer 115 functions as the gate insulating layer. Note that an insulating layer different from the insulating layer 107c may be used as the gate insulating layer.

[0096] The following describes the components included in the transistor 100T of this embodiment.

[0097] <Components of a transistor> [Semiconductor layer 108] The semiconductor material that can be used in the semiconductor layer 108 is not particularly limited. For example, a single-element semiconductor or a compound semiconductor can be used. As a single-element semiconductor, for example, silicon or germanium can be used. As a compound semiconductor, for example, gallium arsenide and silicon germanium can be used. As a compound semiconductor, an organic substance having semiconductor properties or a metal oxide (also called an oxide semiconductor) having semiconductor properties can be used. These semiconductor materials may contain impurities as dopants.

[0098] The crystallinity of the semiconductor material used in the semiconductor layer 108 is not particularly limited, and any amorphous semiconductor or a crystalline semiconductor (single-crystal semiconductor, polycrystalline semiconductor, microcrystalline semiconductor, or semiconductor having a crystalline region in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0099] The semiconductor layer 108 preferably has a metal oxide (oxide semiconductor). Examples of metal oxides that can be used in the semiconductor layer 108 include indium oxide, gallium oxide, and zinc oxide. The metal oxide preferably contains at least indium (In) or zinc (Zn). Furthermore, the metal oxide preferably has two or three elements selected from indium, element M, and zinc. Element M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, antimony, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, cobalt, and magnesium. In particular, element M is preferably one or more selected from aluminum, gallium, yttrium, and tin. Gallium is more preferred for element M.

[0100] The semiconductor layer 108 can be made of, for example, indium oxide, indium gallium oxide (In-Ga oxide), indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), gallium zinc oxide (Ga-Zn oxide), indium aluminum zinc oxide (In-Al-Zn oxide, also written as IAZO), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide, also written as IGZTO), indium gallium aluminum zinc oxide (In-Ga-Al-Zn oxide, also written as IGAZO or IAGZO), etc. Alternatively, silicon-containing indium tin oxide can be used.

[0101] Here, the composition of the metal oxide in the semiconductor layer 108 greatly affects the electrical characteristics and reliability of the transistor 100T. For example, by increasing the ratio of indium atoms to the sum of the total number of atoms of all metal elements contained in the metal oxide, a transistor with a large on-current can be realized.

[0102] When using an In-Zn oxide for the semiconductor layer 108, it is preferable to use a metal oxide in which the atomic ratio of indium is equal to or greater than the atomic ratio of zinc. For example, metal oxides with atomic ratios of metal elements of In:Zn=1:1, In:Zn=2:1, In:Zn=3:1, In:Zn=4:1, In:Zn=5:1, In:Zn=7:1, or In:Zn=10:1, or close to these, can be used.

[0103] When using an In-Sn oxide for the semiconductor layer 108, it is preferable to use a metal oxide in which the atomic ratio of indium is equal to or greater than that of tin. For example, metal oxides with atomic ratios of metal elements of In:Sn=1:1, In:Sn=2:1, In:Sn=3:1, In:Sn=4:1, In:Sn=5:1, In:Sn=7:1, or In:Sn=10:1, or close to these, can be used.

[0104] When using an In-Sn-Zn oxide for the semiconductor layer 108, a metal oxide with a higher atomic ratio of indium than that of tin can be applied. Furthermore, it is preferable to use a metal oxide with a higher atomic ratio of zinc than that of tin. For example, the atomic ratios of the metal elements can be In:Sn:Zn=2:1:3, In:Sn:Zn=3:1:2, In:Sn:Zn=4:2:3, In:Sn:Zn=4:2:4.1, In:Sn:Zn=5:1:3, In:Sn:Zn=5:1:6, In:Sn:Zn=5:1:7, In:Sn:Zn=5:1:8, In:Sn:Zn=6:1:6, In Metal oxides with the following ratios can be used: Sn:Zn=10:1:3, In:Sn:Zn=10:1:6, In:Sn:Zn=10:1:7, In:Sn:Zn=10:1:8, In:Sn:Zn=5:2:5, In:Sn:Zn=10:1:10, In:Sn:Zn=20:1:10, In:Sn:Zn=40:1:10, or near these ratios.

[0105] When using an In-Al-Zn oxide for the semiconductor layer 108, a metal oxide with a higher atomic ratio of indium than that of aluminum can be applied. Furthermore, it is preferable to use a metal oxide with a higher atomic ratio of zinc than that of aluminum. For example, metal oxides with atomic ratios of metal elements such as In:Al:Zn=2:1:3, In:Al:Zn=3:1:2, In:Al:Zn=4:2:3, In:Al:Zn=4:2:4.1, In:Al:Zn=5:1:3, In:Al:Zn=5:1:6, In:Al:Zn=5:1:7, In:Al:Zn=5:1:8, In:Al:Zn=6:1:6, In:Al:Zn=10:1:3, In:Al:Zn=10:1:6, In:Al:Zn=10:1:7, In:Al:Zn=10:1:8, In:Al:Zn=5:2:5, In:Al:Zn=10:1:10, In:Al:Zn=20:1:10, In:Al:Zn=40:1:10, or near these values ​​can be used.

[0106] When using an In-Ga-Zn oxide for the semiconductor layer 108, a metal oxide can be used in which the atomic ratio of indium to the sum of the atomic numbers of all contained metal elements is higher than the atomic ratio of gallium. Furthermore, it is even more preferable to use a metal oxide in which the atomic ratio of zinc is higher than the atomic ratio of gallium. For example, the semiconductor layer 108 can use metal oxides with atomic ratios of metal elements of In:Ga:Zn=2:1:3, In:Ga:Zn=3:1:2, In:Ga:Zn=4:2:3, In:Ga:Zn=4:2:4.1, In:Ga:Zn=5:1:3, In:Ga:Zn=5:1:6, In:Ga:Zn=5:1:7, In:Ga:Zn=5:1:8, In:Ga:Zn=6:1:6, In:Ga:Zn=10:1:3, In:Ga:Zn=10:1:6, In:Ga:Zn=10:1:7, In:Ga:Zn=10:1:8, In:Ga:Zn=5:2:5, In:Ga:Zn=10:1:10, In:Ga:Zn=20:1:10, In:Ga:Zn=40:1:10, or near these values.

[0107] When using an In-M-Zn oxide for the semiconductor layer 108, a metal oxide can be applied in which the atomic ratio of indium to the sum of the atomic numbers of all contained metal elements is higher than the atomic ratio of element M. Furthermore, it is even more preferable to use a metal oxide in which the atomic ratio of zinc is higher than the atomic ratio of element M. For example, the semiconductor layer 108 can use metal oxides with atomic ratios of metal elements of In:M:Zn=2:1:3, In:M:Zn=3:1:2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:3, In:M:Zn=5:1:6, In:M:Zn=5:1:7, In:M:Zn=5:1:8, In:M:Zn=6:1:6, In:M:Zn=10:1:3, In:M:Zn=10:1:6, In:M:Zn=10:1:7, In:M:Zn=10:1:8, In:M:Zn=5:2:5, In:M:Zn=10:1:10, In:M:Zn=20:1:10, In:M:Zn=40:1:10, or near these values.

[0108] By increasing the indium content of the metal oxide, a transistor with a high on-current can be created. Applying this transistor to a transistor requiring a high on-current allows for the formation of a circuit with excellent electrical characteristics.

[0109] For the analysis of the composition of metal oxides, for example, energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MS), or inductively coupled plasma atomic emission spectroscopy (ICP-AES) can be used. Alternatively, a combination of these methods may be used for the analysis. Note that for elements with low content, the actual content may differ from the content obtained by the analysis due to the effect of analytical accuracy. For example, if the content of element M is low, the content of element M obtained by the analysis may be lower than the actual content.

[0110] In this specification, a "nearby composition" includes a range of ±30% of the desired atomic ratio. For example, when describing an atomic ratio of In:M:Zn=4:2:3 or a composition near that ratio, it includes cases where the atomic ratio of indium is 4, the atomic ratio of M is 1 or more and 3 or less, and the atomic ratio of zinc is 2 or more and 4 or less. Also, when describing an atomic ratio of In:M:Zn=5:1:6 or a composition near that ratio, it includes cases where the atomic ratio of indium is 5, the atomic ratio of M is greater than 0.1 and 2 or less, and the atomic ratio of zinc is 5 or more and 7 or less. Furthermore, when describing an atomic ratio of In:M:Zn=1:1:1 or a composition near that ratio, it includes cases where the atomic ratio of indium is 1, the atomic ratio of M is greater than 0.1 and 2 or less, and the atomic ratio of zinc is greater than 0.1 and 2 or less.

[0111] Metal oxides can be suitably formed using sputtering or atomic layer deposition (ALD). However, when forming metal oxides by sputtering, the atomic ratio of the target material may differ from that of the metal oxide. In particular, with zinc, the atomic ratio of the metal oxide may be lower than that of the target material. Specifically, it may be between 40% and 90% of the zinc content in the target material.

[0112] The semiconductor layer 108 may be a laminated structure having two or more metal oxide layers. The two or more metal oxide layers of the semiconductor layer 108 may have the same or substantially the same composition. By using a laminated structure of metal oxide layers with the same composition, for example, the same sputtering target can be used for formation, thereby reducing manufacturing costs.

[0113] The two or more metal oxide layers of the semiconductor layer 108 may have different compositions. For example, a laminated structure can be suitably used in which a first metal oxide layer has a composition of In:M:Zn=1:3:4 [atomic ratio] or close to that, and a second metal oxide layer provided on the first metal oxide layer has a composition of In:M:Zn=1:1:1 [atomic ratio] or close to that. Furthermore, it is particularly preferable to use gallium or aluminum as element M. For example, a laminated structure can be used in which one selected from indium oxide, indium gallium oxide, and IGZO is used, and one selected from IAZO, IAGZO, and ITZO®.

[0114] The semiconductor layer 108 preferably uses a crystalline metal oxide layer. For example, a metal oxide layer having a CAAC (c-axis aligned crystal) structure, a polycrystalline structure, or a microcrystalline (nc: nano-crystal) structure can be used. By using a crystalline metal oxide layer for the semiconductor layer 108, the defect level density in the semiconductor layer 108 can be reduced, and a highly reliable transistor can be realized.

[0115] The higher the crystallinity of the metal oxide layer used in the semiconductor layer 108, the lower the defect level density in the semiconductor layer 108 can be. On the other hand, by using a metal oxide layer with low crystallinity, it is possible to realize a transistor that can carry a large current.

[0116] The semiconductor layer 108 may be a laminated structure of two or more metal oxide layers with different crystallinity. For example, it may be a laminated structure of a first metal oxide layer and a second metal oxide layer provided on the first metal oxide layer, wherein the second metal oxide layer may have regions with higher crystallinity than the first metal oxide layer. Alternatively, the second metal oxide layer may have regions with lower crystallinity than the first metal oxide layer. The two or more metal oxide layers of the semiconductor layer 108 may have the same or substantially the same composition. By using a laminated structure of metal oxide layers with the same composition, manufacturing costs can be reduced because, for example, they can be formed using the same sputtering target. For example, by using the same sputtering target and varying the oxygen flow rate ratio, a laminated structure of two or more metal oxide layers with different crystallinity can be formed. The two or more metal oxide layers of the semiconductor layer 108 may have different compositions.

[0117] When an oxide semiconductor is used for semiconductor layer 108, the carrier concentration of the oxide semiconductor in the region that functions as a channel formation region is 1 × 10⁻⁶ 18 cm -3 The following is preferable: 1 × 10 17 cm -3 It is more preferable that it be less than 1 × 10 16 cm -3 It is even more preferable that it be less than 1 × 10 13 cm -3 It is even more preferable that it be less than 1 × 10 12 cm -3 It is even more preferable that it be less than . There are no particular limitations on the lower limit of the carrier concentration of the oxide semiconductor in the region that functions as a channel-forming region, but for example, 1 × 10 -9 cm -3 It can be done this way.

[0118] Transistors using oxide semiconductors (hereinafter referred to as OS transistors) have extremely high field-effect mobility compared to transistors using amorphous silicon. Furthermore, OS transistors exhibit remarkably low source-drain leakage current (hereinafter also called off-current) in the off state, allowing them to retain charge stored in a capacitor connected in series with the transistor for extended periods. Additionally, the application of OS transistors can reduce the power consumption of semiconductor devices.

[0119] [Insulating layer 107] When an oxide semiconductor is used for the semiconductor layer 108, an inorganic insulating material can preferably be used for the insulating layer 107 (insulating layer 107a, insulating layer 107b, and insulating layer 107c). The insulating layer 107 may also have a laminated structure of an inorganic insulating material and an organic insulating material.

[0120] As the inorganic insulating material, one or more oxides, oxidized nitrides, nitride oxides, and nitrides can be used. The insulating layer 107 can be, for example, one or more silicon oxide, silicon oxidized nitride, aluminum oxide, hafnium oxide, yttrium oxide, zirconium oxide, gallium oxide, tantalum oxide, magnesium oxide, lanthanum oxide, cerium oxide, neodymium oxide, silicon nitride, silicon oxide nitride, and aluminum nitride.

[0121] In this specification, the term "oxide-nitride" refers to a material in which the oxygen content is greater than the nitrogen content. The term "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, silicon oxide-nitride refers to a material in which the oxygen content is greater than the nitrogen content, and silicon nitride oxide refers to a material in which the nitrogen content is greater than the oxygen content.

[0122] It is preferable to use an oxide or oxidized nitride for the insulating layer 107b. It is preferable to use a film that releases oxygen upon heating for the insulating layer 107b. For example, silicon oxide or silicon oxidized nitride can be suitably used for the insulating layer 107b.

[0123] By releasing oxygen from the insulating layer 107b, oxygen can be supplied from the insulating layer 107b to the semiconductor layer 108. By supplying oxygen from the insulating layer 107b to the semiconductor layer 108, particularly to the channel formation region of the semiconductor layer 108, oxygen vacancies (V) in the semiconductor layer 108 can be reduced. O ) and V O This reduces H (defects where hydrogen fills an oxygen vacancy), resulting in a transistor that exhibits good electrical characteristics and is highly reliable. It is preferable that the insulating layer 107b has a high oxygen diffusion coefficient. By increasing the oxygen diffusion coefficient of the insulating layer 107b, oxygen can diffuse more easily through the insulating layer 107b, efficiently supplying oxygen from the insulating layer 107b to the semiconductor layer 108. Other methods for supplying oxygen to the semiconductor layer 108 include heating in an oxygen-containing atmosphere or plasma treatment in an oxygen-containing atmosphere.

[0124] Oxygen deficiency (V) in the channel formation region of transistor 100T O ) and V O H is preferably low. In particular, when the channel length L100 is short, oxygen deficiency (V) in the channel formation region is preferable. O ) and V O The impact of H on the electrical properties and reliability becomes significant. For example, if V flows from the source region or drain region to the channel formation region... O When H diffuses, the carrier concentration in the channel formation region increases, which may cause fluctuations in the threshold voltage of transistor 100T or a decrease in reliability. O The effect of H diffusion on electrical properties and reliability increases as the channel length L100 of transistor 100T decreases. By supplying oxygen from the insulating layer 107b to the semiconductor layer 108, and especially to the channel formation region of the semiconductor layer 108, oxygen deficiency (V) can be reduced. O ) and V OH can be reduced. Therefore, it is possible to realize transistors with short channel lengths that have good electrical characteristics and high reliability.

[0125] It is preferable that insulating layer 107a and insulating layer 107c are impermeable to oxygen. Insulating layer 107a and insulating layer 107c function as blocking films that suppress the detachment of oxygen from insulating layer 107b. Furthermore, it is preferable that insulating layer 107a and insulating layer 107c are impermeable to hydrogen. Insulating layer 107a and insulating layer 107c function as blocking films that suppress the diffusion of hydrogen from outside the transistor through insulating layer 107 to semiconductor layer 108. It is preferable that insulating layer 107a and insulating layer 107c have high film densities. By increasing the film densities of insulating layer 107a and insulating layer 107c, the blocking properties of oxygen and hydrogen can be improved. It is preferable that the film densities of insulating layer 107a and insulating layer 107c are higher than the film densities of insulating layer 107b. When silicon oxide or silicon oxide-nitride is used for the insulating layer 107b, the insulating layer 107a and insulating layer 107c can preferably be, for example, silicon nitride, silicon oxide nitride, or aluminum oxide. It is preferable that the insulating layer 107a and insulating layer 107c each have a region with a higher nitrogen content than the insulating layer 107b. For example, materials with a higher nitrogen content than the insulating layer 107b can be used for the insulating layer 107a and insulating layer 107c. It is preferable that nitrides or oxide nitrides are used for the insulating layer 107a and insulating layer 107c. For example, silicon nitride or silicon oxide nitride can preferably be used for the insulating layer 107a and insulating layer 107c.

[0126] If oxygen contained in the insulating layer 107b diffuses upward from a region of the insulating layer 107b that does not come into contact with the semiconductor layer 108 (for example, the upper surface of the insulating layer 107b), the amount of oxygen supplied from the insulating layer 107b to the semiconductor layer 108 may decrease. By providing an insulating layer 107c on top of the insulating layer 107b, the diffusion of oxygen contained in the insulating layer 107b from a region of the insulating layer 107b that does not come into contact with the semiconductor layer 108 can be suppressed. Similarly, by providing an insulating layer 107a below the insulating layer 107b, the diffusion of oxygen from a region of the insulating layer 107b that does not come into contact with the semiconductor layer 108 can be suppressed. Therefore, the amount of oxygen supplied from the insulating layer 107b to the semiconductor layer 108 increases, and oxygen deficiencies (V) in the semiconductor layer 108 are reduced. O ) and V O The H value can be reduced. Therefore, a transistor with good electrical characteristics and high reliability can be produced.

[0127] Oxygen contained in the insulating layer 107b can oxidize the conductive layer 112a and conductive layer 112b, potentially increasing their resistance. Furthermore, the oxidation of the conductive layer 112a and conductive layer 112b by the oxygen in the insulating layer 107b can reduce the amount of oxygen supplied from the insulating layer 107b to the semiconductor layer 108. By providing an insulating layer 107a between the insulating layer 107b and the conductive layer 112a, the oxidation of the conductive layer 112a and the resulting increase in resistance can be suppressed. Similarly, by providing an insulating layer 107c between the insulating layer 107b and the conductive layer 112b, the oxidation of the conductive layer 112b and the resulting increase in resistance can be suppressed. In addition, the amount of oxygen supplied from the insulating layer 107b to the semiconductor layer 108 increases, reducing oxygen deficiencies (V) in the semiconductor layer 108. O ) and V O This allows for a reduction in H, resulting in a transistor that exhibits good electrical characteristics and is highly reliable.

[0128] When hydrogen diffuses into semiconductor layer 108, it reacts with oxygen atoms contained in the oxide semiconductor to form water, creating an oxygen vacancy (V O ) may be formed. Furthermore, V OH may be formed, leading to a high carrier density. By providing insulating layers 107a and 107c, oxygen vacancies (V) in the semiconductor layer 108 can be reduced. O ) and V O This allows for a reduction in H, resulting in a transistor that exhibits good electrical characteristics and is highly reliable.

[0129] The insulating layers 107a and 107c are preferably of a thickness that functions as an oxygen and hydrogen blocking film. If the insulating layers 107a and 107c are too thin, their blocking function may be reduced. On the other hand, if the insulating layers 107a and 107c are too thick, the area of ​​the semiconductor layer 108 in contact with the insulating layer 107b becomes smaller, which may reduce the amount of oxygen supplied from the insulating layer 107b to the semiconductor layer 108. The insulating layers 107a and 107c may each be thinner than the insulating layer 107b.

[0130] In transistor 100T, oxygen is supplied from the insulating layer 107 to the semiconductor layer 108, resulting in an oxygen deficiency (V) in the channel formation region. O ) and V O H is reduced. Therefore, it is possible to create a transistor that exhibits good electrical characteristics and is highly reliable.

[0131] Furthermore, the configuration may be one or both of the insulating layers 107a and 107c omitted.

[0132] [Conductive layer 112a, conductive layer 112b, conductive layer 104e, conductive layer 115] The conductive layers 112a, 112b, 104e, and 115, which function as source electrodes, drain electrodes, or gate electrodes, can each be formed using one or more of the following: chromium, copper, aluminum, gold, silver, zinc, tantalum, titanium, tungsten, manganese, nickel, iron, cobalt, molybdenum, and niobium, or an alloy containing one or more of the aforementioned metals. The conductive layers 112a, 112b, 104e, and 115 can each preferably be made from low-resistance conductive materials containing one or more of copper, silver, gold, or aluminum. Copper or aluminum are particularly preferred due to their excellent mass-producibility.

[0133] The conductive layers 112a, 112b, 104e, and 115 can each be made of a metal oxide film (also called an oxide conductor (OC)). Examples of oxide conductors include In-Sn oxide (ITO), In-W oxide, In-W-Zn oxide, In-Ti oxide, In-Ti-Sn oxide, In-Zn oxide, In-Sn-Si oxide (ITSO), and In-Ga-Zn oxide.

[0134] Here, we will explain oxide conductors. For example, when an oxygen vacancy is formed in a metal oxide having semiconductor properties, and hydrogen is added to the oxygen vacancy, a donor level is formed near the conduction band. As a result, the metal oxide becomes highly conductive and turns into a conductor. A metal oxide that has turned into a conductor can be called an oxide conductor.

[0135] The conductive layers 112a, 112b, 104e, and 115 may each be a laminated structure of a conductive film containing the aforementioned oxide conductor (metal oxide) and a conductive film containing a metal or alloy. By using a conductive film containing a metal or alloy, the wiring resistance can be reduced.

[0136] Conductive layers 112a, 112b, 104e, and 115 may each be coated with a Cu-X alloy film (where X is Mn, Ni, Cr, Fe, Co, Mo, Ta, or Ti). Using a Cu-X alloy film allows for processing using a wet etching process, thus reducing manufacturing costs.

[0137] The conductive layer 112a, conductive layer 112b, conductive layer 104e, and conductive layer 115 may each be made of the same material, or they may each be made of different materials.

[0138] Here, we will specifically explain the conductive layers 112a and 112b, using a configuration in which a metal oxide is used for the semiconductor layer 108 as an example.

[0139] When an oxide semiconductor is used for semiconductor layer 108, the oxygen contained in semiconductor layer 108 may oxidize conductive layer 112a and conductive layer 112b, potentially increasing their resistance. The oxygen contained in insulating layer 107b may also oxidize conductive layer 112a and conductive layer 112b, potentially increasing their resistance. Furthermore, the oxidation of conductive layer 112a and conductive layer 112b by the oxygen contained in semiconductor layer 108 can lead to oxygen vacancies (V) in semiconductor layer 108. O In some cases, the amount of oxygen supplied from the insulating layer 107b to the semiconductor layer 108 may increase due to oxidation of the conductive layer 112a and conductive layer 112b by the oxygen contained in the insulating layer 107b.

[0140] It is preferable that conductive layers 112a and 112b each use materials that are resistant to oxidation. It is preferable that conductive layers 112a and 112b each use oxide conductors. For example, In-Sn oxide (ITO) or In-Sn-Si oxide (ITSO) can be suitably used. A nitride conductor may also be used for conductive layer 112a. Examples of nitride conductors include tantalum nitride and titanium nitride. Conductive layer 112a may have a laminated structure of the aforementioned materials.

[0141] By using materials that are difficult to be oxidized for the conductive layer 112a and the conductive layer 112b, it is possible to suppress the oxidation by oxygen contained in the semiconductor layer 108 or oxygen contained in the insulating layer 107b, and prevent the increase in resistance. Also, an increase in oxygen vacancies (V O ) in the semiconductor layer 108 is suppressed, and the amount of oxygen supplied from the insulating layer 107b to the semiconductor layer 108 can be increased. Therefore, oxygen vacancies (V O ) and V O H in the semiconductor layer 108 can be reduced, and a transistor with good electrical characteristics and high reliability can be obtained.

[0142] Note that the same material may be used for each of the conductive layer 112a and the conductive layer 112b, or different materials may be used.

[0143] The conductive layer 112b has a region in contact with the transistor 100T. By using a material that is difficult to be oxidized for the conductive layer 112b, oxygen vacancies (V O ) and V O H in the semiconductor layer 108 can be reduced.

[0144] As described above, it is preferable to use materials that are difficult to be oxidized for the conductive layer 112a and the conductive layer 112b in contact with the semiconductor layer 108. However, when using materials that are difficult to be oxidized, the resistance may increase. Since the conductive layer 112a and the conductive layer 112b function as wiring, it is preferable that the resistance is low. Therefore, by using a material that is difficult to be oxidized for the conductive layer 112a_1 having a region in contact with the semiconductor layer 108 and using a material with low resistance for the conductive layer 112a_2 having no region in contact with the semiconductor layer 108, the resistance of the conductive layer 112a can be lowered. Furthermore, oxygen vacancies (V O ) and V O H in the semiconductor layer 108 can be reduced, and a transistor with good electrical characteristics and high reliability can be obtained.

[0145] As described above, particularly when the channel length L100 is short, oxygen vacancies (V O) and V O The impact on the electrical properties and reliability of H becomes significant. By using a material that is resistant to oxidation in the conductive layer 112a_1, oxygen vacancies (V) in the semiconductor layer 108 can be reduced. O ) and V O The increase in H can be suppressed. Therefore, it is possible to realize transistors with short channel lengths that have good electrical characteristics and high reliability.

[0146] The conductive layer 112a_1 can preferably use one or more oxide conductors and nitride conductors. The conductive layer 112a_2 preferably uses a material with lower resistance than the conductive layer 112a_1. The conductive layer 112a_2 can preferably use one or more of copper, aluminum, titanium, tungsten, and molybdenum, or an alloy comprising one or more of the aforementioned metals. Specifically, In-Sn-Si oxide (ITSO) can preferably be used for the conductive layer 112a_1, and tungsten for the conductive layer 112a_2.

[0147] The configuration of the conductive layer 112a can be determined according to the required wiring resistance of the conductive layer 112a. For example, if the length of the wiring (conductive layer 112a) is short and the required wiring resistance is relatively high, the conductive layer 112a may be a single-layer structure, and a material that is resistant to oxidation may be used. On the other hand, if the length of the wiring (conductive layer 112a) is long and the required wiring resistance is relatively low, it is preferable to apply a laminated structure of the conductive layer 112a consisting of a material that is resistant to oxidation and a material with low resistance.

[0148] Furthermore, the configuration of the conductive layer 112a can be applied to other conductive layers.

[0149] [Insulating layer 106] The insulating layer 106, which functions as a gate insulating layer, preferably has a low defect density. A low defect density in the insulating layer 106 allows for a transistor that exhibits good electrical characteristics. Furthermore, the insulating layer 106 preferably has a high dielectric breakdown voltage. A high dielectric breakdown voltage in the insulating layer 106 allows for a highly reliable transistor.

[0150] The insulating layer 106 can be, for example, one or more insulating oxides, oxidized nitrides, nitride oxides, and nitrides. The insulating layer 106 can be one or more silicon oxide, silicon oxidized nitride, silicon nitride, silicon oxide, aluminum oxide, aluminum oxidized nitride, aluminum nitride, hafnium oxide, hafnium oxidized nitride, gallium oxide, gallium oxidized nitride, yttrium oxide, yttrium oxidized nitride, and Ga-Zn oxide. The insulating layer 106 may be a single layer or a laminate. The insulating layer 106 may be, for example, a laminated structure of oxides and nitrides.

[0151] In the case of miniature transistors, if the thickness of the gate insulating layer becomes too thin, the leakage current may increase. By using a material with a high dielectric constant (also called a high-k material) for the gate insulating layer, it is possible to lower the voltage during transistor operation while maintaining the physical thickness. Examples of high-k materials include gallium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium, oxides containing aluminum and hafnium, oxides containing silicon and hafnium, oxides containing silicon and hafnium, or nitrides containing silicon and hafnium.

[0152] It is preferable that the insulating layer 106 releases little impurities (e.g., water and hydrogen) from itself. By reducing the release of impurities from the insulating layer 106, the diffusion of impurities into the semiconductor layer 108 is suppressed, resulting in a transistor that exhibits good electrical characteristics and is highly reliable.

[0153] Here, we will specifically explain the insulating layer 106, using a configuration in which a metal oxide is used for the semiconductor layer 108 as an example.

[0154] To improve the interfacial properties with the semiconductor layer 108, it is preferable to use an oxide material for at least the side of the insulating layer 106 that is in contact with the semiconductor layer 108. The insulating layer 106 can preferably be one or more of silicon oxide and silicon oxynitride. Furthermore, it is even more preferable to use a film for the insulating layer 106 that releases oxygen upon heating.

[0155] The insulating layer 106 may also have a laminated structure. The insulating layer 106 can have a laminated structure consisting of an oxide film on the side in contact with the semiconductor layer 108 and a nitride film on the side in contact with the conductive layer 104e. For example, silicon oxide and one or more silicon oxynitride can be suitably used as the oxide film. Silicon nitride can be suitably used as the nitride film.

[0156] [Circuit board 102] There are no major restrictions on the material of the substrate 102, but it must have at least enough heat resistance to withstand subsequent heat treatment. For example, single-crystal semiconductor substrates made of silicon or silicon carbide, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, SOI substrates, glass substrates, quartz substrates, sapphire substrates, ceramic substrates, or organic resin substrates may be used as the substrate 102. Alternatively, a substrate on which a semiconductor element is mounted may be used as the substrate 102. The shape of the semiconductor substrate and the insulating substrate may be circular or rectangular.

[0157] A flexible substrate may be used as the substrate 102, and transistors 100T, etc., may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate 102 and the transistors 100T, etc. The release layer can be used to separate the semiconductor device from the substrate 102 after it has been partially or completely completed on it, and to transfer it to another substrate. In this case, the transistors 100T, etc., can be transferred to a substrate with poor heat resistance or to a flexible substrate.

[0158] The above is a description of the components of the 100T transistor.

[0159] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0160] (Embodiment 3) This embodiment describes the configuration when the vertical transistor described in Embodiment 2 is connected by diodes and applied to the circuit 18 shown in Embodiment 1. The basic configuration of each transistor is the same as that of transistor 100T shown in Figures 7(A), (B) or 8(A), (B), and the explanation of each element is omitted. In addition, the drawings described in this embodiment use the same reference numerals as those used for transistor 100T shown in Figures 7(A), (B) and 8(A), (B).

[0161] Figure 9(A) is a cross-sectional view illustrating the connection configuration of the series-connected transistors in circuit 18 shown in Figure 3, specifically the (x-1)th transistor Tr(x), the xth transistor Tr(x), and the (x+1)th transistor Tr(x+1).

[0162] In the configuration shown in Figure 9(A), the conductive layer 112b is fixed to the drain (D) and the conductive layer 112a is fixed to the source (S) of each transistor. Furthermore, while the electrical connection configuration of the electrodes of transistor Tr(x) is described below as a representative example, the electrodes of other transistors can be connected in a similar manner.

[0163] In transistor Tr(x), the conductive layer 112b extends to the opening 142 provided in the insulating layer 106 and is electrically connected to the conductive layer 104e which acts as the gate (G) electrode. In this configuration, transistor Tr(x) is a diode connection in which the drain electrode and gate electrode are electrically connected.

[0164] Furthermore, the conductive layer 112b extends to the opening 141a provided in the insulating layer 107 and is electrically connected to the conductive layer 112a of transistor Tr(x-1). In this configuration, the drain and gate of transistor Tr(x) are electrically connected to the source of transistor Tr(x-1).

[0165] Furthermore, in transistor Tr(x), the conductive layer 112a extends to the opening 141b provided in the insulating layer 107 and is electrically connected to the conductive layer 112b and conductive layer 104e of transistor Tr(x+1). In this configuration, the source of transistor Tr(x) is electrically connected to the drain and gate of transistor Tr(x+1).

[0166] The above explains the diode connection and series connection of transistors Tr(x-1) to Tr(x+1).

[0167] In Figure 9(A), an example is shown in which openings 141a and 142 are spaced apart. However, as shown in Figure 9(B), opening 142 may be provided so as to have an overlapping area with opening 141a. By using the configuration shown in Figure 9(B), the area of ​​the contact portion (opening) can be reduced, thereby increasing the integration density of the circuit.

[0168] Figure 10(A) shows a configuration different from Figures 9(A) and (B). Figure 10(A) is a cross-sectional view illustrating the connection configuration of the series-connected transistors in circuit 18 shown in Figure 3, specifically the (x-1)th transistor Tr(x-1), the xth transistor Tr(x), the (x+1)th transistor Tr(x+1), and the (x+2)th transistor Tr(x+2).

[0169] In the configuration shown in Figure 10(A), a first transistor in which conductive layer 112b is the drain and conductive layer 112a is the source and a second transistor in which conductive layer 112b is the source and conductive layer 112a is the drain are alternately connected in series. In Figure 10(A), an example is shown in which transistors Tr(x) and Tr(x+2) are the first transistors and transistors Tr(x-1) and Tr(x+1) are the second transistors.

[0170] The electrical connection configuration of transistors Tr(x-1) through Tr(x+2) will be explained using Figure 10(B), which illustrates the source (S), gate (G), and drain (D) of each transistor.

[0171] In transistor Tr(x), the conductive layer 104e acting as the gate (G) electrode extends to the opening 144a provided in the insulating layer 106 and is electrically connected to the conductive layer 112b acting as the drain electrode (D). In this configuration, transistor Tr(x) is a diode connection in which the drain electrode and gate electrode are electrically connected.

[0172] Furthermore, the conductive layer 112b of transistor Tr(x) is shared with transistor Tr(x-1). In transistor Tr(x-1), the conductive layer 112b acts as the source electrode (S). In other words, with this configuration, the drain and gate of transistor Tr(x) are electrically connected to the source of transistor Tr(x-1).

[0173] Furthermore, in transistor Tr(x), the conductive layer 112a acting as the source electrode (S) is shared with transistor Tr(x+1). In transistor Tr(x+1), the conductive layer 112a acts as the drain electrode (D). Also, the conductive layer 112a is electrically connected to the conductive layer 104e acting as the gate electrode (G) of transistor Tr(x+1) through an opening 144b provided in the insulating layers 107 and 106. In this configuration, the source of transistor Tr(x) is electrically connected to the drain and gate of transistor Tr(x+1).

[0174] The above explains the diode connection and series connection of transistors Tr(x-1) to Tr(x+2).

[0175] Note that the connection configuration of transistor Tr(x+2), which acts as the first transistor just like transistor Tr(x), and the transistors before and after it is the same as described above. Also, the connection configuration of transistors Tr(x-1) and Tr(x+1), which act as the second transistors, and the transistors before and after them is the same as described above, but with the source and drain reversed.

[0176] Figure 11(A) is a cross-sectional view illustrating the connection configuration of the series-connected transistors in circuit 18 shown in Figure 4, specifically the (x-1)th transistor Tr(x-1), the xth transistor Tr(x), and the (x+1)th transistor Tr(x+1).

[0177] In the configuration shown in Figure 11(A), the conductive layer 112b is fixed to the drain (D) and the conductive layer 112a is fixed to the source (S) of each transistor. In transistors Tr(x-1) to Tr(x+1), the gate, source, and drain connection configuration of each transistor is the same as in Figure 9(A), except that there is a back gate and wiring that supplies potential to the back gate.

[0178] Transistor Tr(x-1) has a conductive layer 115(x-1) that acts as a back gate. Similar to transistor Tr(x-1), transistor Tr(x) has a conductive layer 115(x), and transistor Tr(x+1) has a conductive layer 115(x+1).

[0179] Furthermore, the conductive layer 116(x-1) is electrically connected to the source electrode (conductive layer 112a) of transistor Tr(x-1). In Figure 11(A), an example is shown in which the conductive layer 116(x-1) is electrically connected to the conductive layer 112a via the conductive layers 112b and 104e, but the conductive layer 116(x-1) may be connected to the conductive layer 112b without going through the conductive layer 104e. Alternatively, the conductive layer 116(x-1) may be connected to the conductive layer 112a without going through the conductive layers 112b and 104e.

[0180] Similar to transistor Tr(x-1), conductive layer 116(x) is electrically connected to the source electrode (conductive layer 112a) of transistor Tr(x). Similarly, conductive layer 116(x+1) is electrically connected to the source electrode (conductive layer 112a) of transistor Tr(x+1). Conductive layers 116(x) and 116(x+1) may also be connected to conductive layer 112b without going through conductive layer 104e, just like conductive layer 116(x-1). Alternatively, they may be connected to conductive layer 112a without going through conductive layer 112b and conductive layer 104e.

[0181] Here, the conductive layer 116(x) corresponds to the wiring connecting the back gate of transistor Tr(x-1) and the source of transistor Tr(x), as shown in the circuit diagram in Figure 11(B). In other words, the conductive layer 115(x-1), which acts as the back gate of transistor Tr(x-1), is electrically connected to the conductive layer 116(x), which is electrically connected to the source of transistor Tr(x).

[0182] Similarly, conductive layer 116(x-1) is electrically connected to the conductive layer that acts as the back gate of transistor Tr(x-2) (not shown). Also, conductive layer 116(x+1) is electrically connected to conductive layer 115(x) that acts as the back gate of transistor Tr(x).

[0183] Furthermore, as shown in Figure 11(C), the gate, source, and drain connections of each transistor can be configured in the same way as in Figure 9(B).

[0184] Figure 12(A) shows a configuration different from Figures 11(A) and (B). Figure 12(A) is a cross-sectional view illustrating the connection configuration of the series-connected transistors in circuit 18 shown in Figure 3, specifically the (x-1)th transistor Tr(x-1), the xth transistor Tr(x), the (x+1)th transistor Tr(x+1), and the (x+2)th transistor Tr(x+2).

[0185] In the configuration shown in Figure 12(A), a first transistor, in which conductive layer 112b is the drain and conductive layer 112a is the source, and a second transistor, in which conductive layer 112b is the source and conductive layer 112a is the drain, are alternately connected in series. In Figure 12(A), an example is shown where transistors Tr(x) and Tr(x+2) are the first transistors, and transistors Tr(x-1) and Tr(x+1) are the second transistors.

[0186] The electrical connection configuration of transistors Tr(x-1) through Tr(x+2) will be explained using Figure 12(C), which illustrates the source (S), gate (G), drain (D), and back gate (BG) of each transistor.

[0187] In transistors Tr(x-1) through Tr(x+2), the gate, source, and drain connection configurations of each transistor are the same as in Figure 10(A), except that they have a back gate and wiring that supplies potential to the back gate.

[0188] Transistor Tr(x-1) has a conductive layer 115(x-1) that acts as a back gate. Similar to transistor Tr(x-1), transistor Tr(x) has a conductive layer 115(x), transistor Tr(x+1) has a conductive layer 115(x+1), and transistor Tr(x+2) has a conductive layer 115(x+2).

[0189] Furthermore, the conductive layer 116(x-1) is electrically connected to the source electrode (conductive layer 112b) of transistor Tr(x-1). In Figure 12(A), an example is shown in which the conductive layer 116(x-1) is electrically connected to the conductive layer 112b via the conductive layer 104e, but the conductive layer 116(x-1) may also be connected to the conductive layer 112b without going through the conductive layer 104e.

[0190] Similar to transistor Tr(x-1), conductive layer 116(x+1) is electrically connected to the source electrode (conductive layer 112b) of transistor Tr(x+1) via conductive layer 104e. Alternatively, conductive layer 116(x+1) may be connected to conductive layer 112b without going through conductive layer 104e, similar to conductive layer 116(x-1).

[0191] Furthermore, the conductive layer 116(x) is electrically connected to the source electrode (conductive layer 112a) of transistor Tr(x) via conductive layer 104e. Similarly, the conductive layer 116(x+2) is electrically connected to the source electrode (conductive layer 112a) of transistor Tr(x+2) via conductive layer 104e. Note that conductive layers 116(x) and 116(x+2) may also be connected to conductive layer 112a without using conductive layer 104e.

[0192] Here, the conductive layer 116(x) corresponds to the wiring connecting the back gate of transistor Tr(x-1) and the source of transistor Tr(x), as shown in the circuit diagram in Figure 12(B). In other words, the conductive layer 115(x-1), which acts as the back gate of transistor Tr(x-1), is electrically connected to the conductive layer 116(x), which is electrically connected to the source of transistor Tr(x).

[0193] Similarly, conductive layer 116(x-1) is electrically connected to the conductive layer that acts as the back gate of transistor Tr(x-2) (not shown). Also, conductive layer 116(x+1) is electrically connected to conductive layer 115(x) that acts as the back gate of transistor Tr(x). Furthermore, conductive layer 116(x+2) is electrically connected to conductive layer 115(x+1) that acts as the back gate of transistor Tr(x+1).

[0194] Furthermore, in the transistor that can be used in circuit 18, an offset region may be provided between the channel region of the semiconductor layer and the source or drain region, where the gate's electric field is less likely to be applied.

[0195] For example, as shown in Figure 13(A), in the semiconductor layer 108, an offset region OF1 can be defined as a region that does not come into contact with the conductive layer 112b and does not overlap with the conductive layer 104e. This configuration can be formed using a lithography process.

[0196] Alternatively, as shown in Figure 13(B), an offset region OF2 can be defined as a region in the semiconductor layer 108 that does not come into contact with the conductive layer 112a and is located below the bottom B of the conductive layer 104e in the opening 141 (the interface between the conductive layer 104e and the insulating layer 106). This configuration can be formed by providing an insulating layer 109 on the semiconductor layer 108 located at the bottom of the opening 141. Note that an offset region OF2 can also be provided by making the insulating layer 106 thicker.

[0197] Alternatively, as shown in Figure 13(C), both offset region OF1 and offset region OF2 may be provided. Furthermore, the configurations in Figures 13(A) to (C) are examples, and the offset regions can be formed with other structures.

[0198] The offset region acts as a resistor connected in series with the channel. Therefore, it can be used to adjust the resistance value of the transistor. Alternatively, an oxide conductor with a higher resistance value than metal can be used for part or all of the conductive layers 112a and 112b as the resistor connected in series with the channel.

[0199] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0200] (Embodiment 4) In this embodiment, the pixel circuits of the display device 30 will be described.

[0201] As shown in Figure 1, the pixels of a display device according to one embodiment of the present invention have sub-pixels 11 and 12. The pixel circuit PIX1 of sub-pixel 11 has a light-emitting device that emits visible light. The pixel circuit PIX2 of sub-pixel 12 has a light-receiving device.

[0202] Figure 14(A) shows an example of the pixel circuit PIX1 of the sub-pixel 11. The pixel circuit PIX1 includes a light-emitting device EL1, transistors M1, M2, M3, and capacitor C1. Here, an example using a light-emitting diode as the light-emitting device EL1 is shown. It is preferable to use an organic EL element that emits visible light as the light-emitting device EL1.

[0203] Transistor M1 has its gate electrically connected to wiring G1, one of its source or drain electrically connected to wiring S1, and the other of its source or drain electrically connected to one electrode of capacitor C1 and the gate of transistor M2. One of the source or drain of transistor M2 is electrically connected to wiring V2, and the other is electrically connected to the anode of light-emitting device EL1 and one of the source or drain of transistor M3. Transistor M3 has its gate electrically connected to wiring G2, and the other of its source or drain electrically connected to wiring V0. The cathode of light-emitting device EL1 is electrically connected to wiring V1.

[0204] A constant potential is supplied to wiring V1 and wiring V2, respectively. Light emission can be achieved by setting the anode side of the light-emitting device EL1 to a high potential and the cathode side to a low potential. Transistor M1 is controlled by the signal supplied to wiring G1 and functions as a selection transistor to control the selected state of the pixel circuit PIX1. Transistor M2 functions as a drive transistor that controls the current flowing to the light-emitting device EL1 according to the potential supplied to the gate.

[0205] When transistor M1 is conducting, the potential supplied to wiring S1 is supplied to the gate of transistor M2, and the luminescence brightness of light-emitting device EL1 can be controlled according to that potential. Transistor M3 is controlled by a signal supplied to wiring G2. This allows the potential between transistor M2 and light-emitting device EL1 to be reset to a constant potential supplied from wiring V0, and the potential can be written to the gate of transistor M2 while the source potential of transistor M2 is stabilized.

[0206] Figure 14(B) shows an example of a pixel circuit PIX2, which is different from the pixel circuit PIX1. The pixel circuit PIX2 has a boost function. The pixel circuit PIX2 includes a light-emitting device EL2, transistors M4, M5, M6, M7, capacitors C2 and C3. Here, an example is shown in which a light-emitting diode is used as the light-emitting device EL2. The pixel circuit PIX2 can be used in one or more of the sub-pixels 11 of the pixel 10.

[0207] Transistor M4 has its gate electrically connected to wiring G1, one of its source or drain electrically connected to wiring S4, and the other of its source or drain electrically connected to one electrode of capacitor C2, one electrode of capacitor C3, and the gate of transistor M6. Transistor M5 has its gate electrically connected to wiring G6, one of its source or drain electrically connected to wiring S5, and the other of its source or drain electrically connected to the other electrode of capacitor C3.

[0208] One of the sources or drains of transistor M6 is electrically connected to wiring V2, and the other is electrically connected to the anode of light-emitting device EL2 and one of the sources or drains of transistor M7. Transistor M7 has its gate electrically connected to wiring G2, and the other of its source or drain is electrically connected to wiring V0. The cathode of light-emitting device EL2 is electrically connected to wiring V1.

[0209] Transistor M4 is controlled by a signal supplied to wiring G1, and transisttor M5 is controlled by a signal supplied to wiring G6. Transistor M6 functions as a drive transistor that controls the current flowing through light-emitting device EL2 according to the potential supplied to its gate.

[0210] The emission luminance of light-emitting device EL2 can be controlled according to the potential supplied to the gate of transisttor M6. Transistor M7 is controlled by a signal supplied to wiring G2. The potential between transisttor M6 and light-emitting device EL2 can be reset to a constant potential supplied from wiring V0, and the potential can be written to the gate of transisttor M6 while stabilizing the source potential of transisttor M6. Also, by setting the potential supplied from wiring V0 to the same potential as wiring V1 or a potential lower than wiring V1, the emission of light-emitting device EL2 can be suppressed.

[0211] The boosting function of pixel circuit PIX2 will be described below.

[0212] First, the potential "D1" of wiring S4 is supplied to the gate of transisttor M6 via transisttor M4, and the reference potential "V ref " is supplied to the other electrode of capacitor C3 via transisttor M5 at a timing overlapping this. At this time, "D1 - V ref " is held in capacitor C3. Next, the gate of transisttor M6 is set to floating, and the potential "D2" of wiring S5 is supplied to the other electrode of capacitor C3 via transisttor M5. Here, the potential "D2" is a potential for addition.

[0213] At this time, assuming the capacitance value of capacitor C3 is C3, the capacitance value of capacitor C2 is C2, and the capacitance value of the gate of transisttor M6 is C M6 , the potential of the gate of transisttor M6 is D1 + (C3 / (C3 + C2 + C M6 )) × (D2 - V ref )). Here, assuming that the value of C3 is sufficiently larger than the value of C2 + C M6 C3 / (C3 + C2 + CM6 ) approximates 1. Therefore, the gate potential of transistor M6 is “D1 + (D2 - V ref It can be said that this approximates )". And D1 = D2, V ref If = 0, then “D1+(D2-V ref ))” = “2D1”.

[0214] In other words, if the circuit is designed properly, it will be possible to supply a potential to the gate of transistor M6 that is approximately twice the potential that can be input from wiring S4 or S5.

[0215] This action allows for the generation of a high voltage within the pixel circuit. Therefore, the voltage input to the pixel circuit can be reduced, thereby lowering the power consumption of the drive circuit.

[0216] Furthermore, the pixel circuit PIX2 may have the configuration shown in Figure 14(C). The pixel circuit PIX2 shown in Figure 14(C) differs from the pixel circuit PIX2 shown in Figure 14(B) in that it has a transistor M8. The gate of transistor M8 is electrically connected to wiring G1, one of its source or drain is electrically connected to the other of its source or drain of transistor M5 and the other electrode of capacitor C3, and the other of its source or drain is electrically connected to wiring V0. In addition, one of its source or drain is connected to wiring S4.

[0217] In the pixel circuit PIX2 shown in Figure 14(B), as described above, the reference potential and the potential for addition are supplied to the other electrode of capacitor C3 via transistor M5. In this case, two wires S4 and S5 are required, and in wire S5, the reference potential and the potential for addition must be rewritten alternately.

[0218] In the pixel circuit PIX2 shown in Figure 14(C), although the number of transistors M8 increases, a dedicated path for supplying the reference potential is provided, thus reducing the wiring S5. Furthermore, the gate of transistor M8 can be connected to wiring G1, and wiring V0 can be used for supplying the reference potential, so the number of wires connected to transistor M8 does not increase. In addition, since the reference potential and the potential for addition are not alternately rewritten with a single wire, low power consumption and high-speed operation are possible.

[0219] Note that in Figures 14(B) and 14(C), the reference potential "V" is used. ref Alternatively, the inverted potential "D1B" of "D1" may be used. In this case, approximately three times the potential that can be input from wiring S4 or S5 can be supplied to the gate of transistor M6. Note that the inverted potential means a potential that is different from the original potential, but whose absolute difference from a certain reference potential is the same (or approximately the same). If the original potential is "D1", the inverted potential is "D1B", and the reference potential is V0, then the relationship V0 = (D1 + D1B) / 2 is sufficient.

[0220] In the display device of this embodiment, an image may be displayed by causing the light-emitting device to emit light in a pulsed manner. By shortening the driving time of the light-emitting device, the power consumption of the display device and the heat generation can be reduced. Organic EL elements are particularly suitable because they have excellent frequency characteristics. The frequency can be, for example, 1 kHz or more and 100 MHz or less.

[0221] Figure 14(D) shows an example of the pixel circuit PIX3 of sub-pixel 12. The pixel circuit PIX3 includes a light-receiving device PD, transistors M9, M10, M11, M12, and capacitor C4. Here, an example is shown in which a photodiode is used as the light-receiving device PD.

[0222] The photodetector PD has its cathode electrically connected to wiring V1 and its anode electrically connected to either the source or drain of transistor M9. Transistor M9 has its gate electrically connected to wiring G3 and its other source or drain electrically connected to one electrode of capacitor C4, either the source or drain of transistor M10, and the gate of transistor M11. Transistor M10 has its gate electrically connected to wiring G4 and its other source or drain electrically connected to wiring V3. Transistor M11 has its source or drain electrically connected to wiring V4 and its other source or drain electrically connected to either the source or drain of transistor M12. Transistor M12 has its gate electrically connected to wiring G5 and its other source or drain electrically connected to wiring OUT.

[0223] Constant potentials are supplied to wirings V1, V3, and V4, respectively. When the photodetector PD is driven with reverse bias, a potential lower than that of wiring V1 is supplied to wiring V3. Transistor M10 is controlled by a signal supplied to wiring G5 and has the function of resetting the potential of the node connected to the gate of transistor M11 to the potential supplied to wiring V3. Transistor M9 is controlled by a signal supplied to wiring G3 and has the function of controlling the timing at which the potential of the above node changes according to the current flowing through the photodetector PD. Transistor M11 functions as an amplifying transistor that provides an output according to the potential of the above node. Transistor M12 is controlled by a signal supplied to wiring G6 and functions as a selection transistor for reading the output according to the potential of the above node with an external circuit connected to wiring OUT.

[0224] Here, it is preferable to use transistors in which a metal oxide (oxide semiconductor) is used in the semiconductor layer where the channel is formed for each of the transistors M1 to M12 in the pixel circuits PIX1 to PIX3.

[0225] Transistors using metal oxides, which have a wider bandgap and lower carrier density than silicon, can achieve extremely low off-currents. Therefore, this low off-current allows the charge stored in a capacitor connected in series with the transistor to be retained for extended periods.

[0226] Therefore, it is preferable to use transistors with oxide semiconductors applied to transistors M1, M4, M5, M8, M9, and M10, which have one or both of their sources or drains connected to capacitors C1, C2, C3, or C4. By using transistors with oxide semiconductors applied to the sub-pixels 12, a global shutter method can be applied that performs charge accumulation operation simultaneously in all pixels without complicating the circuit configuration and operating method.

[0227] Furthermore, the manufacturing cost of other transistors can also be reduced by using transistors that utilize oxide semiconductors in a similar manner.

[0228] Furthermore, transistors M1 to M12 can also be transistors in which silicon is applied as the semiconductor in which the channel is formed. In particular, using highly crystalline silicon such as single-crystal silicon or polycrystalline silicon is preferable because it can achieve high field-effect mobility, enabling faster operation.

[0229] Alternatively, one or more of the transistors M1 to M12 may be made of oxide semiconductor material, while the others may be made of silicon.

[0230] Although Figures 14(A) to 14(D) illustrate an example using an n-channel transistor, a p-channel transistor can also be used.

[0231] The transistors included in pixel circuit PIX1, the transistors included in pixel circuit PIX2, and the transistors included in pixel circuit PIX3 are preferably formed side by side on the same substrate.

[0232] Also, it is preferable to provide one or more layers having one or both of a transistor and a capacitor at a position overlapping with the light receiving device PD, the light emitting device EL1, or the light emitting device EL2. Thereby, the effective occupation area of each pixel circuit can be reduced, and a high-definition light receiving portion or display portion can be realized.

[0233] This embodiment can be implemented in appropriate combination with at least a part of other embodiments described in this specification.

[0234] (Embodiment 5) In this embodiment, the configuration of the display portion in the display device of one aspect of the present invention will be described. Each of the pixel 110, the sub-pixel having the light emitting device, and the sub-pixel having the light receiving device described in this embodiment corresponds to the pixel 10, the sub-pixel 11, and the sub-pixel 12 in Embodiment 1.

[0235] FIG. 15(A) shows a top view of a display device 100 having a light emitting device and a light receiving device. The display device 100 has a display portion in which a plurality of pixels 110 are arranged. In FIG. 15(A), some sub-pixels are shown, and an example in which a pixel 110 is composed of a plurality of sub-pixels (sub-pixels 110a, 110b, 110c, 110d) arranged at equal intervals is shown.

[0236] In this specification and the like, the row direction may be referred to as the X direction, and the column direction may be referred to as the Y direction. The X direction and the Y direction intersect, and intersect perpendicularly or substantially perpendicularly (see FIG. 15(A)).

[0237] The top surface shape of the sub-pixel shown in FIG. 15(A) corresponds to the top surface shape of the light emitting region or the light receiving region. Note that the top surface shape of the sub-pixel may be a polygon such as a triangle, a quadrilateral (including a rectangle and a square), a pentagon, a shape in which the corners of these polygons are rounded, an ellipse, or a circle.

[0238] Furthermore, the layout of the circuitry in the subpixel is not limited to the subpixel range shown in Figure 15(A), and the circuit components may be located outside of it. For example, the transistor in subpixel 110a may be located within the range of subpixel 110b, or some or all of it may be located outside the range of subpixel 110a.

[0239] The aperture ratios of the sub-pixels 110a, 110b, 110c, and 110d can be determined as appropriate. The aperture ratios of the sub-pixels 110a, 110b, 110c, and 110d may be different, or two or more may be equal or approximately equal.

[0240] A display device according to one aspect of the present invention has a light-receiving device in each pixel. For example, of the four subpixels of the pixel 110 shown in Figure 15(A), three may have light-emitting devices and one may have a light-receiving device.

[0241] Each of the three subpixels can have a light-emitting device with a different emitted color. For example, there may be three subpixels with red (R), green (G), and blue (B), or three subpixels with yellow (Y), cyan (C), and magenta (M).

[0242] In the following explanation, we will describe an example where sub-pixels 110a, 110b, and 110c each have a light-emitting device, and sub-pixel 110d has a light-receiving device 150. Furthermore, while we will describe the light-emitting device 130c of sub-pixel 110c as an element constituting the light-emitting device, the common elements can also be applied to the light-emitting devices of sub-pixels 110a and 110b, respectively.

[0243] Figure 15(B) shows a cross-sectional view between the dashed line X1 and X2 in Figure 15(A). As shown in Figure 15(B), an insulating layer is provided on the layer 101 containing the transistor, and a light-emitting device 130c and a light-receiving device 150 are provided on the insulating layer. In addition, a protective layer 131 is provided so as to cover the light-emitting device 130c and the light-receiving device 150.

[0244] A light-shielding layer 135 is bonded to the protective layer 131 via an adhesive layer 122. The light-shielding layer 135 is provided between one adjacent subpixel and the other subpixel.

[0245] Figure 15(B) shows an example where light emitted from the light-emitting device 130c is emitted towards the substrate 120, and light entering from the substrate 120 is incident on the light-receiving device 150 (see optical Lem and optical Lin).

[0246] Furthermore, an insulating layer 125 and an insulating layer 127 on the insulating layer 125 are provided in the region between adjacent light-emitting devices 130c and light-receiving devices 150. Although not shown in Figure 15(B), insulating layers 125 and 127 are also provided in the region between adjacent light-emitting devices.

[0247] [Light-emitting devices] First, let's describe the light-emitting device. One embodiment of the present invention is a top-emission type display device that emits light in the direction opposite to the substrate on which the light-emitting device is formed.

[0248] The layer 101 containing the transistors can be a laminated structure having multiple transistors provided on a substrate and an insulating layer covering these transistors. The insulating layer on the transistors may be a single layer or a laminated structure. Figure 15(B) shows the insulating layer on the transistors: insulating layer 255a, insulating layer 255b on insulating layer 255a, and insulating layer 255c on insulating layer 255b.

[0249] Various inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride-oxide insulating films can be suitably used as insulating layers 255a, 255b, and 255c, respectively. For insulating layers 255a and 255c, it is preferable to use oxide insulating films or oxidative nitride insulating films such as silicon oxide films, silicon oxidative nitride films, and aluminum oxide films, respectively. For insulating layer 255b, it is preferable to use nitride insulating films or nitride-oxide insulating films such as silicon nitride films and silicon nitride-oxide films. More specifically, it is preferable to use silicon oxide films as insulating layers 255a and 255c, and silicon nitride films as insulating layer 255b. It is preferable that insulating layer 255b has the function of an etching protective film.

[0250] In this specification, "oxide nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, when "silicon oxynitride" is written, it refers to a material in which the oxygen content is greater than the nitrogen content, and when "silicon nitride oxide" is written, it refers to a material in which the nitrogen content is greater than the oxygen content.

[0251] The light-emitting device can emit light in the following colors: infrared, red, green, blue, cyan, magenta, yellow, or white. Furthermore, the color purity can be increased by adding a microcavity structure to the light-emitting device. For example, the light-emitting device 130c can emit light in one of three colors: red (R), green (G), or blue (B).

[0252] As the light-emitting device, it is preferable to use an OLED or a QLED. Examples of light-emitting materials for the light-emitting device include fluorescent materials, phosphorescent materials, and TADF materials. Not only organic compounds but also inorganic compounds (such as quantum dot materials) can be used as the light-emitting material for the light-emitting device. In addition, LEDs such as microLEDs can also be used as the light-emitting device.

[0253] Of the pair of electrodes included in the light-emitting device, one electrode functions as a cathode and the other functions as an anode. Hereinafter, there may be cases where the pixel electrode functions as an anode and the common electrode functions as a cathode are taken as examples for explanation.

[0254] The light-emitting device 130c has a pixel electrode 111c on an insulating layer 255c, an island-shaped layer 113c on the pixel electrode 111c, a common layer 114 on the layer 113c, and a common electrode 117 on the common layer 114. In the light-emitting device 130c, the layer 113c and the common layer 114 can be collectively referred to as an EL layer.

[0255] By providing the EL layer in an island shape for each light-emitting device, the leakage current between adjacent light-emitting devices can be suppressed. Thereby, crosstalk caused by unintended light emission can be prevented, and a display device with extremely high contrast can be realized. In particular, a display device with high current efficiency at low luminance can be realized.

[0256] A single structure (a structure having only one light-emitting unit) can be applied to the light-emitting device of the present embodiment.

[0257] When using a light-emitting device with a single structure, the layer 113c can have a light-emitting layer that emits red, green, or blue light.

[0258] In the light-emitting device with a single structure, the layer 113c may have one or more of a hole injection layer, a hole transport layer, a hole blocking layer, a charge generation layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0259] The layer 113c can, for example, have a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer in this order. Also, an electron blocking layer may be provided between the hole transport layer and the light-emitting layer. Also, a hole blocking layer may be provided between the electron transport layer and the light-emitting layer. Also, an electron injection layer may be provided on the electron transport layer.

[0260] Alternatively, layer 113c may have an electron injection layer, an electron transport layer, an emissive layer, and a hole transport layer in this order. Furthermore, a hole blocking layer may be present between the electron transport layer and the emissive layer. Also, an electron blocking layer may be present between the hole transport layer and the emissive layer. Furthermore, a hole injection layer may be present on the hole transport layer.

[0261] Furthermore, a tandem structure can be applied to the light-emitting device of this embodiment. The light-emitting device with a tandem structure has two or more light-emitting units in layer 113c, and each light-emitting unit may be configured to include one or more light-emitting layers. In addition, each light-emitting unit may have one or more of the following: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer. It is preferable to provide a charge generation layer between each light-emitting unit. The charge generation layer has at least a charge generation region.

[0262] For example, layer 113c can have a laminated structure consisting of light-emitting unit 113_1, charge generation layer 113_3, and light-emitting unit 113_2 (see enlarged view of layer 113c in Figure 16). Note that in the drawings used in this embodiment, the charge generation layer may be shown with a dashed line.

[0263] When using a tandem light-emitting device, layer 113c can have multiple light-emitting units that emit light of the same color. For example, in the configuration shown in Figure 16, both light-emitting unit 113_1 and light-emitting unit 113_2 can use the same type of light-emitting unit that emits red, green, or blue light.

[0264] Furthermore, to produce white light emission, a tandem structure can be used, combining light-emitting units of different colors. To obtain white light emission, a configuration is needed in which the light emitted by multiple light-emitting units is combined to produce white light emission. For example, in the configuration shown in Figure 16, one of the light-emitting units 113_1 and 113_2 can be a blue-emitting unit, and the other a yellow-emitting unit. Alternatively, a red-emitting unit and a cyan-emitting unit can be combined. Alternatively, a green-emitting unit and a magenta-emitting unit can be combined.

[0265] Alternatively, the configuration may consist of three light-emitting units combined together. For example, a configuration may be made by combining a red light-emitting unit, a green light-emitting unit, and a blue light-emitting unit. Alternatively, a configuration may be made by combining a blue light-emitting unit, a yellow or yellow-green light-emitting unit, and a blue light-emitting unit. Alternatively, a configuration may be made by combining a blue light-emitting unit, green and red light-emitting units, and a blue light-emitting unit.

[0266] The number of layers and the order of colors for the light-emitting unit can be, from the anode side, a two-layer structure of B (blue light-emitting unit) and Y (yellow light-emitting unit), a two-layer structure of B and light-emitting unit X, a three-layer structure of B, Y, B, or a three-layer structure of B, X, B. The number of layers and the order of colors for the light-emitting layer in light-emitting unit X can be, from the anode side, a two-layer structure of R (red light-emitting layer) and Y (yellow light-emitting layer), a two-layer structure of R and G (green light-emitting layer), a two-layer structure of G and R, a three-layer structure of G, R, G, or a three-layer structure of R, G, R. In addition, other layers may be provided between the two light-emitting layers.

[0267] Tandem light-emitting devices, which emit light from multiple light-emitting units, require a relatively high voltage for light emission, but the current required to achieve the same light intensity as a single light-emitting device (a configuration with one light-emitting unit) is smaller. Therefore, in a tandem structure, the current stress per light-emitting unit can be reduced, extending the device lifespan. In other words, a highly reliable display device can be formed by using a tandem light-emitting device.

[0268] In the configuration shown in Figure 16, it is preferable that the light-emitting unit 113_2 has a light-emitting layer and a carrier transport layer (electron transport layer or hole transport layer) on the light-emitting layer. Alternatively, it is preferable that the light-emitting unit 113_2 has a light-emitting layer and a carrier block layer (hole block layer or electron block layer) on the light-emitting layer. Alternatively, it is preferable that the light-emitting unit 113_2 has a light-emitting layer, a carrier block layer on the light-emitting layer, and a carrier transport layer on the carrier block layer. Since the surface of the light-emitting unit 113_2 is exposed during the manufacturing process of the display device, by providing one or both of the carrier transport layer and the carrier block layer on the light-emitting layer, it is possible to suppress the exposure of the light-emitting layer to the outermost surface and reduce the damage to the light-emitting layer. This can improve the reliability of the light-emitting device. If there are three or more light-emitting units, it is preferable that the light-emitting unit provided in the uppermost layer has a light-emitting layer and one or both of the carrier transport layer and the carrier block layer on the light-emitting layer.

[0269] The configuration and materials of the tandem light-emitting device will be described in detail in other embodiments.

[0270] The common layer 114 may have an electron injection layer or a hole injection layer. Alternatively, the common layer 114 may have an electron transport layer and an electron injection layer stacked together, or a hole transport layer and a hole injection layer stacked together. The common layer 114 and the common electrode 117 are shared by the light-emitting device of each subpixel.

[0271] In Figure 15(B), layer 113c is formed to cover the edge of the pixel electrode 111c. A mask layer 118c is located on layer 113c of the light-emitting device 130c. The mask layer 118c is a remnant of a mask layer that was prepared in contact with the upper surface of layer 113c during the processing of layer 113c.

[0272] In Figure 15(B), one end of the mask layer 118c is aligned with or approximately aligned with the end of layer 113c, and the other end of the mask layer 118c is located on layer 113c. Here, it is preferable that the other end of the mask layer 118c overlaps with layer 113c and the pixel electrode 111c.

[0273] The sides of layer 113c are covered by insulating layer 125. Insulating layer 127 overlaps with the sides of layer 113c via insulating layer 125.

[0274] Furthermore, a portion of the upper surface of layer 113c is covered by mask layer 118c. Insulating layers 125 and 127 overlap with a portion of the upper surface of layer 113c via mask layer 118c. Note that the upper surface of layer 113c is not limited to the upper surface of the flat portion that overlaps with the upper surface of the pixel electrode, but can also include the upper surfaces of the inclined portion and the flat portion located outside the upper surface of the pixel electrode.

[0275] By covering a portion of the top surface and sides of layer 113c with at least one of the insulating layer 125, insulating layer 127, and mask layer 118c, contact between the common layer 114 (or common electrode 117) and the pixel electrode 111c and the sides of layer 113c can be suppressed. Therefore, short circuits between the upper and lower layers of the light-emitting device can be suppressed.

[0276] The insulating layer 127 is provided on the insulating layer 125 so as to fill the recesses in which the insulating layer 125 is formed. The insulating layer 127 can be configured to overlap a portion of the upper surface and sides of the layer 113c via the insulating layer 125. Preferably, the insulating layer 127 covers at least a portion of the sides of the insulating layer 125.

[0277] By providing insulating layers 125 and 127, the gaps between adjacent island-shaped layers can be filled, thereby reducing extreme irregularities on the surface of layers formed on the island-shaped layers (e.g., carrier injection layers and common electrodes), making them flatter. Consequently, the coverage of the carrier injection layers and common electrodes can be improved.

[0278] The common layer 114 and the common electrode 117 are provided on layer 113c, the mask layer 118c, the insulating layer 125, and the insulating layer 127. Before the insulating layer 125 and the insulating layer 127 are provided, a step difference occurs due to the region where the pixel electrode and island-shaped EL layer are provided and the region where the pixel electrode and island-shaped EL layer are not provided (the region between light-emitting devices).

[0279] A display device according to one aspect of the present invention has insulating layers 125 and 127, which flatten the step and improve the coverage of the common layer 114 and the common electrode 117. Therefore, connection failures due to step breaks can be suppressed. In addition, it is possible to suppress the local thinning of the common electrode 117 due to the step and the resulting increase in electrical resistance.

[0280] The upper surface of the insulating layer 127 preferably has a shape that is more flat, but it may have convex portions, convex curved surfaces, concave curved surfaces, or recesses.

[0281] As shown in Figure 15(B), by providing the mask layer 118c, insulating layer 125, and insulating layer 127, the common layer 114 and common electrode 117 can be formed with high coverage. Furthermore, it is possible to prevent the formation of areas where the common layer 114 and common electrode 117 are divided, and areas where the film thickness is locally thin.

[0282] Therefore, it is possible to suppress connection failures caused by the divided portions and increases in electrical resistance caused by locally thin film thicknesses in the common layer 114 and common electrode 117 between each light-emitting device. As a result, the display device according to one aspect of the present invention can improve the display quality.

[0283] Next, we will describe examples of materials for insulating layer 125 and insulating layer 127.

[0284] The insulating layer 125 can be an insulating layer having an inorganic material. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used for the insulating layer 125. The insulating layer 125 may be a single layer or a laminated structure. Examples of oxide insulating films include silicon oxide film, aluminum oxide film, magnesium oxide film, indium gallium zinc oxide film, gallium oxide film, germanium oxide film, yttrium oxide film, zirconium oxide film, lanthanum oxide film, neodymium oxide film, hafnium oxide film, and tantalum oxide film. Examples of nitride insulating films include silicon nitride film and aluminum nitride film. Examples of oxidative nitride insulating films include silicon oxidative nitride film and aluminum oxidative nitride film. Examples of nitride oxide insulating films include silicon nitride oxide film and aluminum nitride oxide film. In particular, aluminum oxide is preferred because it has a high selectivity ratio with the EL layer during etching and has the function of protecting the EL layer during the formation of the insulating layer 127, which will be described later.

[0285] In particular, by applying an inorganic insulating film such as an aluminum oxide film, a hafnium oxide film, or a silicon oxide film formed by the ALD method to the insulating layer 125, it is possible to form an insulating layer 125 with fewer pinholes and excellent protection for the EL layer. Alternatively, the insulating layer 125 may have a laminated structure of a film formed by the ALD method and a film formed by the sputtering method. For example, the insulating layer 125 may have a laminated structure of an aluminum oxide film formed by the ALD method and a silicon nitride film formed by the sputtering method.

[0286] Preferably, the insulating layer 125 functions as a barrier insulating layer against at least one of water and oxygen. Furthermore, preferably, the insulating layer 125 has the function of suppressing the diffusion of at least one of water and oxygen. Also, preferably, the insulating layer 125 has the function of capturing or fixing (also known as gettering) at least one of water and oxygen.

[0287] In this specification, the term "barrier insulating layer" refers to an insulating layer that has barrier properties. Furthermore, in this specification, "barrier properties" refers to a function that suppresses the diffusion of the corresponding substance (also known as low permeability), or a function that captures or fixes the corresponding substance (also known as gettering).

[0288] The insulating layer 125 has the function of a barrier insulating layer or a gettering function, thereby suppressing the intrusion of impurities (typically at least one of water and oxygen) that could diffuse from the outside into each light-emitting device. This configuration makes it possible to provide a highly reliable light-emitting device, and furthermore, a highly reliable display device.

[0289] Furthermore, the same material can be used for the insulating layer 125 and the mask layer 118c. In this case, the boundary between the mask layer 118c and the insulating layer 125 becomes unclear, and the mask layer 118c and the insulating layer 125 may be perceived as a single layer.

[0290] The insulating layer 127 provided on the insulating layer 125 has the function of flattening the extreme irregularities in the insulating layer 125 formed between adjacent light-emitting devices.

[0291] As the insulating layer 127, an insulating layer having an organic material can be suitably used. Preferably, a photosensitive organic resin is used as the organic material; for example, a photosensitive resin composition containing an acrylic resin can be used. In this specification, the term "acrylic resin" does not refer only to polymethacrylate esters or methacrylic resins, but may refer to acrylic polymers in a broad sense.

[0292] Furthermore, as the insulating layer 127, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins may be used. Alternatively, as the insulating layer 127, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used. Additionally, a photoresist may be used as the photosensitive resin. Either a positive-type or negative-type material may be used as the photosensitive organic resin.

[0293] The insulating layer 127 may be made of a material that absorbs visible light. By absorbing the light emitted from the light-emitting device, the insulating layer 127 can suppress light leakage (stray light) from the light-emitting device to adjacent light-emitting or light-receiving devices via the insulating layer 127. This improves the display quality and imaging performance of the display device. Furthermore, since the display quality can be improved without using a polarizing plate in the display device, the display device can be made lighter and thinner.

[0294] Examples of materials that absorb visible light include materials containing pigments such as black, materials containing dyes, light-absorbing resin materials (e.g., polyimide), and resin materials that can be used as color filters (color filter materials). In particular, it is preferable to use a resin material which is made by laminating or mixing two or more color filter materials, as this can enhance the visible light shielding effect. In particular, by mixing three or more color filter materials, it is possible to create a black or near-black resin layer.

[0295] Furthermore, as shown in Figure 15(C), a colored layer 137, such as a color filter, may be provided in the region overlapping with the light-emitting device 130c. For example, if the light-emitting device 130c emits white light, a sub-pixel that emits red, green, or blue light can be configured by providing the colored layer 137. Alternatively, the color of the light emitted by the light-emitting device 130c and the color of the colored layer 137 may be the same. This configuration makes it possible to create a sub-pixel that emits light with improved color purity.

[0296] [Light receiving device] Next, the light-receiving device 150 will be described. Note that explanations of elements common to both the light-emitting device 130c and elements serving the same purpose will be omitted.

[0297] A pn-type or pin-type photodiode can be used as the light-receiving device. The light-receiving device functions as a photoelectric conversion device (also called a photoelectric conversion element) that detects light incident on it and generates an electric charge. The amount of charge generated from the light-receiving device is determined by the amount of light incident on it.

[0298] Light-receiving devices can detect either visible light, infrared light, or both. When detecting infrared light, it becomes possible to detect objects even in dark places.

[0299] As the light-receiving device, it is preferable to use an organic photodiode having a layer containing an organic compound. Organic photodiodes are easy to make thin, light, and large in area, and because they offer a high degree of freedom in shape and design, they can be applied to various display devices.

[0300] In one aspect of the present invention, an organic EL device is used as the light-emitting device, and an organic photodiode is used as the light-receiving device. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display device using an organic EL device.

[0301] A light-receiving device can detect light incident on it, generate an electric charge, and extract it as an electric current by driving it with a reverse bias applied between the pixel electrode and the common electrode.

[0302] The same manufacturing methods as for light-emitting devices can be applied to light-receiving devices. The island-shaped active layer (also called the photoelectric conversion layer) of the light-receiving device is not formed using a fine metal mask, but rather by processing after depositing a film that will become the active layer onto one surface, thus enabling the formation of an island-shaped active layer with a uniform thickness. Furthermore, by providing a mask layer on the active layer, damage to the active layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-receiving device.

[0303] The light-receiving device 150 includes a pixel electrode 111d on an insulating layer 255c, a layer 113d on the pixel electrode 111d, a common layer 114 on the layer 113d, and a common electrode 117 on the common layer 114.

[0304] Here, layer 113d includes at least an active layer and preferably has multiple functional layers. For example, functional layers include carrier transport layers (hole transport layers and electron transport layers) and carrier block layers (hole block layers and electron block layers). It is also preferable to have one or more layers on the active layer. By having other layers between the active layer and the mask layer, it is possible to suppress the exposure of the active layer to the outermost surface during the manufacturing process of the display device and reduce damage to the active layer. This can improve the reliability of the photodetector 150. Therefore, it is preferable that layer 113d includes an active layer and a carrier block layer (hole block layer or electron block layer) or a carrier transport layer (electron transport layer or hole transport layer) on the active layer.

[0305] Layer 113d is provided on the light-receiving device 150 but not on the light-emitting device 130c. However, functional layers other than the active layer included in layer 113d may have the same material as functional layers other than the light-emitting layer included in layer 113c. On the other hand, the common layer 114 is a continuous layer shared by the light-receiving device 150 and the light-emitting device 130c.

[0306] Here, layers common to both the light-receiving and light-emitting devices may have different functions in the light-emitting device and the light-receiving device. In this specification, components may be referred to based on their function in the light-emitting device. For example, a hole injection layer functions as a hole injection layer in the light-emitting device and as a hole transport layer in the light-receiving device. Similarly, an electron injection layer functions as an electron injection layer in the light-emitting device and as an electron transport layer in the light-receiving device. Furthermore, layers common to both the light-receiving and light-emitting devices may have the same function in the light-emitting device and the light-receiving device. For example, a hole transport layer functions as a hole transport layer in both the light-emitting and light-receiving devices, and an electron transport layer functions as an electron transport layer in both the light-emitting and light-receiving devices.

[0307] A mask layer 118c is located between layer 113c and the insulating layer 125, and a mask layer 118d is located between layer 113d and the insulating layer 125. Mask layer 118c is a portion of the mask layer that remained after processing layer 113c. Mask layer 118d is a portion of the mask layer that remained after processing layer 113d, which is a layer containing the active layer, by being in contact with the upper surface of layer 113d. Mask layer 118c and mask layer 118d may be made of the same material or different materials.

[0308] The sub-pixel 110d may have a higher aperture ratio than at least one of the sub-pixels 110a, 110b, and 110c. A larger light-receiving area for sub-pixel 110d may make object detection easier. For example, depending on the resolution of the display device and the circuit configuration of the sub-pixels, the aperture ratio of sub-pixel 110d may be higher than that of the other sub-pixels.

[0309] Furthermore, the aperture ratio of sub-pixel 110d may be lower than that of at least one of sub-pixels 110a, 110b, and 110c. By lowering the aperture ratio of sub-pixel 110d, the pinhole effect can be enhanced, resulting in a sharper image.

[0310] Thus, it is preferable to vary the detection wavelength, resolution, and aperture ratio of the sub-pixel 110d depending on the application.

[0311] The protective layer 131 provided on the light-emitting device 130c and the light-receiving device 150 may be a single-layer structure or a laminated structure of two or more layers. Providing the protective layer 131 can improve the reliability of the light-emitting device 130c and the light-receiving device 150.

[0312] The conductivity of the protective layer 131 is not required. The protective layer 131 can be at least one of an insulating film, a semiconductor film, and a conductive film.

[0313] The presence of an inorganic film in the protective layer 131 prevents oxidation of the common electrode 117, suppresses the intrusion of impurities (such as moisture and oxygen) into the light-emitting device and light-receiving device, thereby suppressing degradation of the light-emitting device and light-receiving device and improving the reliability of the display device.

[0314] For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidoxide-nitride insulating films, and nitride-oxide insulating films can be used for the protective layer 131. Specific examples of these inorganic insulating films are given in the description of the insulating layer 125. In particular, the protective layer 131 preferably has a nitride insulating film or a nitride-oxide insulating film, and more preferably a nitride insulating film.

[0315] Furthermore, the protective layer 131 may also be an inorganic film containing In-Sn oxide (also known as ITO), In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or indium gallium zinc oxide (In-Ga-Zn oxide, also known as IGZO). The inorganic film is preferably highly resistive, and more specifically, it is preferably more resistive than the common electrode 117. The inorganic film may further contain nitrogen.

[0316] The protective layer 131 is preferably highly transparent to visible light. ITO, IGZO, and aluminum oxide are preferred because they are inorganic materials that are each highly transparent to visible light.

[0317] As the protective layer 131, for example, a laminated structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a laminated structure of an aluminum oxide film and an IGZO film on the aluminum oxide film can be used. By using such a laminated structure, it is possible to suppress impurities (water, oxygen, etc.) from entering the EL layer.

[0318] Furthermore, the protective layer 131 may have an organic film. The protective layer 131 may have both an organic film and an inorganic film. Examples of organic materials that can be used for the protective layer 131 include organic insulating materials that can be used for the insulating layer 127.

[0319] The protective layer 131 may have a two-layer structure formed using different film deposition methods. Specifically, the first layer of the protective layer 131 may be formed using the ALD method, and the second layer of the protective layer 131 may be formed using the sputtering method.

[0320] As the adhesive layer 122, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0321] The substrate 120 can be made of glass, quartz, ceramics, sapphire, resin, metal, alloy, semiconductor, etc. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. Using a flexible material for the substrate 120 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used as the substrate 120.

[0322] As the substrate 120, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. may be used. Glass with a thickness sufficient to provide flexibility may also be used as the substrate 120.

[0323] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0324] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0325] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic resin film.

[0326] Furthermore, when a film is used as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display device. Therefore, it is preferable to use a film with a low water absorption rate as the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0327] Various optical components can be placed on the outside of the substrate 120. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (such as diffusion films), anti-reflective layers, and light-gathering films. In addition, surface protection layers such as an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and an impact-absorbing layer may be placed on the outside of the substrate 120.

[0328] As a surface protective layer, a glass layer or silica layer (SiO x By providing a protective layer, surface contamination and scratching can be suppressed, which is preferable. Also, as a surface protective layer, DLC (diamond-like carbon), aluminum oxide (AlO2) x ), polyester-based materials, or polycarbonate-based materials may be used. It is preferable to use a material with high transmittance to visible light for the surface protective layer. Furthermore, it is preferable to use a material with high hardness for the surface protective layer.

[0329] In one embodiment of the present invention, the display device has an EL layer arranged in an island-like configuration for each light-emitting device, thereby suppressing the generation of leakage current between sub-pixels. This prevents crosstalk caused by unintended light emission, enabling the realization of a display device with extremely high contrast. Furthermore, by providing an insulating layer with a tapered shape at its edges between adjacent island-like EL layers, it is possible to suppress the occurrence of step breaks during the formation of common electrodes. This suppresses connection failures caused by the divided portions in the common layer and common electrodes. Therefore, the display device in one embodiment of the present invention can achieve both high resolution and high display quality.

[0330] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0331] (Embodiment 6) This embodiment describes a pixel layout applicable to a display device according to one aspect of the present invention.

[0332] [Pixel layout] There are no particular limitations on the arrangement of subpixels, and various methods can be applied. Examples of subpixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements.

[0333] In this embodiment, the top surface shape of the sub-pixel shown in the figure corresponds to the top surface shape of the light-emitting region or the light-receiving region.

[0334] The top surface shape of the subpixel may include, for example, polygons such as triangles, quadrilaterals (including rectangles and squares), pentagons, polygons with rounded corners, ellipses, or circles.

[0335] Furthermore, the circuit layout constituting the subpixel is not limited to the subpixel range shown in the figure; the circuit components may be arranged outside of it.

[0336] Pixel 110, shown in Figures 17(A) to (C), has a stripe arrangement applied to it.

[0337] Figure 17(A) shows an example where each subpixel has a rectangular top surface shape, Figure 17(B) shows an example where each subpixel has a top surface shape formed by connecting two semicircles and a rectangle, and Figure 17(C) shows an example where each subpixel has an elliptical top surface shape.

[0338] The pixels 110 shown in Figures 17(D) to (F) have a matrix array applied to them.

[0339] Figure 17(D) shows an example where each subpixel has a square top surface shape, Figure 17(E) shows an example where each subpixel has a roughly square top surface shape with rounded corners, and Figure 17(F) shows an example where each subpixel has a circular top surface shape.

[0340] Figures 17(G) and (H) show an example where one pixel 110 is composed of 2 rows and 3 columns.

[0341] Pixel 110, shown in Figure 17(G), has three subpixels (subpixels 110a, 110b, and 110c) in the top row (row 1) and one subpixel (subpixel 110d) in the bottom row (row 2). In other words, pixel 110 has subpixel 110a in the left column (column 1), subpixel 110b in the middle column (column 2), subpixel 110c in the right column (column 3), and subpixel 110d across these three columns.

[0342] The pixel 110 shown in Figure 17(H) has three subpixels (subpixels 110a, 110b, and 110c) in the top row (1st row) and three subpixels 110d in the bottom row (2nd row). In other words, the pixel 110 has subpixels 110a and 110d in the left column (1st column), subpixels 110b and 110d in the middle column (2nd column), and subpixels 110c and 110d in the right column (3rd column). As shown in Figure 17(H), by aligning the arrangement of subpixels in the top row and the bottom row, it becomes possible to efficiently remove dust and other debris that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided.

[0343] Figure 17(I) shows an example where one pixel 110 is composed of 3 rows and 2 columns.

[0344] Pixel 110, shown in Figure 17(I), has a sub-pixel 110a in the top row (1st row), a sub-pixel 110b in the middle row (2nd row), a sub-pixel 110c spanning from the 1st to the 2nd row, and one sub-pixel (sub-pixel 110d) in the bottom row (3rd row). In other words, pixel 110 has sub-pixels 110a and 110b in the left column (1st column), a sub-pixel 110c in the right column (2nd column), and a sub-pixel 110d spanning these two columns.

[0345] The pixel 110 shown in Figures 17(A) to (I) is composed of four subpixels: subpixels 110a, 110b, 110c, and 110d. For example, a light-receiving device can be provided in one of the subpixels 110a to 110d, and light-emitting devices can be provided in the other three.

[0346] In each pixel 110 shown in Figures 17(A) to (I), it is preferable, for example, that sub-pixel 110a be a sub-pixel R that emits red light, sub-pixel 110b be a sub-pixel G that emits green light, sub-pixel 110c be a sub-pixel B that emits blue light, and sub-pixel 110d be a sub-pixel S having a light-receiving device. With such a configuration, in the pixel 110 shown in Figures 17(G) and (H), the layout of R, G, and B becomes a stripe arrangement, which can improve the display quality. Also, in the pixel 110 shown in Figure 17(I), the layout of R, G, and B becomes a so-called S-stripe arrangement, which can improve the display quality.

[0347] The wavelength of light detected by the sub-pixel S, which has a light-receiving device, is not particularly limited. The sub-pixel S can be configured to detect either visible light or infrared light, or both.

[0348] If a light-receiving device is not provided, the sub-pixels 110a, 110b, 110c, and 110d can be sub-pixels of four colors: R, G, B, and white (W); sub-pixels of four colors: R, G, B, and Y; or sub-pixels of R, G, B, and infrared (IR).

[0349] As shown in Figures 17(J) and (K), a pixel can be configured to have five types of subpixels.

[0350] Figure 17(J) shows an example where one pixel 110 is composed of 2 rows and 3 columns.

[0351] Pixel 110, shown in Figure 17(J), has three subpixels (subpixels 110a, 110b, and 110c) in the top row (1st row) and two subpixels (subpixels 110d and 110e) in the bottom row (2nd row). In other words, pixel 110 has subpixels 110a and 110d in the left column (1st column), subpixel 110b in the middle column (2nd column), subpixel 110c in the right column (3rd column), and subpixel 110e extending from the 2nd to the 3rd column.

[0352] Figure 17(K) shows an example where one pixel 110 is composed of 3 rows and 2 columns.

[0353] Pixel 110, shown in Figure 17(K), has subpixel 110a in the top row (1st row), subpixel 110b in the middle row (2nd row), subpixel 110c spanning from the 1st to the 2nd row, and two subpixels (subpixels 110d and 110e) in the bottom row (3rd row). In other words, pixel 110 has subpixels 110a, 110b, and 110d in the left column (1st column), and subpixels 110c and 110e in the right column (2nd column).

[0354] In each pixel 110 shown in Figures 17(J) and (K), it is preferable, for example, to set sub-pixel 110a as sub-pixel R that emits red light, sub-pixel 110b as sub-pixel G that emits green light, and sub-pixel 110c as sub-pixel B that emits blue light. With such a configuration, in the pixel 110 shown in Figure 17(J), the layout of R, G, and B becomes a stripe arrangement, which can improve the display quality. Also, in the pixel 110 shown in Figure 17(K), the layout of R, G, and B becomes a so-called S-stripe arrangement, which can improve the display quality.

[0355] Furthermore, in each pixel 110 shown in Figures 17(J) and (K), it is preferable to apply a sub-pixel S having a photodetector to at least one of the sub-pixels 110d and 110e. When photodetectors are used for both sub-pixels 110d and 110e, the configurations of the photodetectors may differ from each other. For example, at least a portion of the wavelength ranges of light detected by each may differ. Specifically, one of the sub-pixels 110d and 110e may have a photodetector that mainly detects visible light, and the other may have a photodetector that mainly detects infrared light.

[0356] Furthermore, in each pixel 110 shown in Figures 17(J) and (K), it is preferable to apply a sub-pixel S having a light-receiving device to one of the sub-pixels 110d and 110e, and a sub-pixel having a light-emitting device that can be used as a light source to the other. For example, it is preferable that one of the sub-pixels 110d and 110e is a sub-pixel IR that emits infrared light, and the other is a sub-pixel S having a light-receiving device that detects infrared light.

[0357] In pixels having sub-pixels R, G, B, IR, and S, an image can be displayed using sub-pixels R, G, and B, while sub-pixel IR is used as a light source to detect the reflected infrared light emitted by sub-pixel IR at sub-pixel S.

[0358] As described above, in one aspect of the present invention, a display device can be configured to have pixels having subpixels with light-emitting devices, and various layouts can be applied to these pixels. Furthermore, in one aspect of the present invention, a display device can be configured to have pixels having both light-emitting devices and light-receiving devices. In this case as well, various layouts can be applied.

[0359] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0360] (Embodiment 7) This embodiment describes a display device according to one aspect of the present invention.

[0361] A display device according to one aspect of the present invention can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television equipment, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal information terminals, and audio playback devices.

[0362] [Display device 100A] Figure 18 shows a perspective view of a display device 100A, which is a display device according to one embodiment of the present invention, and Figure 19(A) shows a cross-sectional view of the display device 100A.

[0363] The display device 100A has a configuration in which substrate 151 and substrate 152 are bonded together. In Figure 18, substrate 152 is shown with a dashed line.

[0364] The display device 100A includes a display unit 162, circuits 164a and 164b, wiring 165a and 165b, etc. Figure 18 also shows an example in which IC chips (integrated circuits) 173a, FPC 172a, IC chips 173b and FPC 172b are mounted on the display device 100A. Therefore, the configuration shown in Figure 18 can also be described as a display module having the display device 100A, IC chips, and FPCs.

[0365] Circuit 164a can be a gate driver for display purposes. Circuit 164b can be a low driver for imaging (light sensing).

[0366] Wiring 165a has the function of supplying signals and power to sub-pixels 11 and 12 and circuits 164a and 164b shown in Figure 1. These signals and power are input externally via FPC 172a or input to wiring 165a from IC chip 173a.

[0367] Figure 18 shows an example where IC chips 173a and 173b are mounted on substrate 151 using the COF method, but they may also be mounted using the TCP method or COG method.

[0368] IC chip 173a can be, for example, an IC chip having the function of a source driver connected to the sub-pixel 11 shown in Figure 1. IC chip 173b can be, for example, an IC chip having the function of a column driver and a readout circuit such as an A / D converter connected to the sub-pixel 12.

[0369] Furthermore, a circuit 167 having the same components as the transistors and other components that constitute the pixel circuit, as shown in Figure 1, is provided on the substrate 151, and is electrically connected to the IC chip 173b via wiring 165b. In addition, some or all of the circuits that constitute the source driver and column driver may be provided on the substrate 151.

[0370] Figure 19(A) shows an example of a cross-section of part of the region including the FPC 172a, part of the region including the circuit 164a, part of the region including the display unit 162, part of the region including the circuit 167, and part of the region including the end of the display device 100A shown in Figure 18.

[0371] The display device 100A shown in Figure 19(A) has transistors 201, 205, 206, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-receiving device 150P, etc., between substrates 151 and 152.

[0372] The light-emitting devices 130R and 130G, and the light-receiving device 150P, have the same stacked structure as the light-emitting device and light-receiving device shown in Figure 15(B), except that the pixel electrode configuration differs.

[0373] The light-emitting device 130R has a conductive layer 112a, a conductive layer 126a on the conductive layer 112a, and a conductive layer 129a on the conductive layer 126a. All of the conductive layers 112a, 126a, and 129a can be called pixel electrodes, or only a part of them can be called pixel electrodes.

[0374] The light-emitting device 130G has a conductive layer 112b, a conductive layer 126b on the conductive layer 112b, and a conductive layer 129b on the conductive layer 126b.

[0375] The light-receiving device 150P has a conductive layer 112d, a conductive layer 126d on the conductive layer 112d, and a conductive layer 129d on the conductive layer 126d.

[0376] The conductive layer 112a is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The edge of the conductive layer 126a is located outside the edge of the conductive layer 112a. The edges of the conductive layer 126a and the conductive layer 129a are aligned or approximately aligned. For example, conductive layers that function as reflective electrodes can be used for conductive layers 112a and 126a, and a conductive layer that functions as a transparent electrode can be used for conductive layer 129a.

[0377] The conductive layers 112b, 126b, and 129b in the light-emitting device 130G, and the conductive layers 112d, 126d, and 129d in the light-receiving device 150P are the same as the conductive layers 112a, 126a, and 129a in the light-emitting device 130R, so a detailed explanation is omitted.

[0378] The conductive layers 112a, 112b, and 112d have recesses formed to cover the openings provided in the insulating layer 214. Layer 128 is embedded in these recesses.

[0379] Layer 128 has the function of flattening the recesses of the conductive layers 112a, 112b, and 112d. Conductive layers 126a, 126b, and 126d are provided on conductive layers 112a, 112b, and 112d and on layer 128, and are electrically connected to conductive layers 112a, 112b, and 112d. Therefore, regions overlapping with the recesses of conductive layers 112a, 112b, and 112d can also be used as light-emitting or light-receiving regions, thereby increasing the aperture ratio of the pixels.

[0380] Layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used for layer 128 as appropriate. In particular, it is preferable that layer 128 be formed using an insulating material, and especially preferable that it be formed using an organic insulating material. For example, an organic insulating material that can be used for the insulating layer 127 described above can be applied to layer 128.

[0381] A protective layer 131 is provided on the light-emitting devices 130R and 130G, and the light-receiving device 150P. A solid encapsulation structure or a hollow encapsulation structure can be applied to seal the light-emitting devices and light-receiving devices. In Figure 19(A), the space between substrate 152 and substrate 151 is filled with an adhesive layer 122, indicating that a solid encapsulation structure is applied.

[0382] Alternatively, the space may be filled with an inert gas (such as nitrogen or argon) to apply a hollow sealing structure. In this case, the adhesive layer 122 may be provided so as not to overlap with the light-emitting device and the light-receiving device. Furthermore, the space may be filled with a resin different from the adhesive layer 122 provided in a frame shape.

[0383] The display device 100A is a top-emission type. The light emitted by the light-emitting device is emitted towards the substrate 152. It is preferable to use a material with high transmittance to visible light for the substrate 152. The pixel electrodes contain a material that reflects visible light, and the counter electrodes (common electrodes 117) contain a material that transmits visible light.

[0384] The laminated structure from the substrate 151 to the insulating layer 214 corresponds to the layer 101 containing the transistor in Embodiment 1.

[0385] Transistors 201, 205, and 206 are all formed on the substrate 151. Transistors 201 and 205 can be manufactured using the same materials and the same process.

[0386] Transistor 206 is a vertical transistor in circuit 167. Details of the vertical transistor can be found in Embodiment 2. In transistors 201, 205, and 206, common materials can be used for the semiconductor layer, insulating layer, and conductive layer.

[0387] On the substrate 151, insulating layers 211, 213, 215, and 214 are provided in this order. A portion of insulating layer 211 functions as a gate insulating layer for each transistor. A portion of insulating layer 213 functions as a gate insulating layer for each transistor. Insulating layer 215 is provided covering the transistors. Insulating layer 214 is provided covering the transistors and functions as a planarization layer. The number of gate insulating layers and insulating layers covering the transistors are not limited and may be a single layer or two or more layers, respectively.

[0388] It is preferable to use a material that does not easily allow impurities such as water and hydrogen to diffuse into at least one layer of the insulating layer covering the transistor. This allows the insulating layer to function as a barrier layer. With such a configuration, the diffusion of impurities from the outside into the transistor can be effectively suppressed, thereby improving the reliability of the display device.

[0389] It is preferable to use inorganic insulating films for insulating layer 211, insulating layer 213, and insulating layer 215. Examples of inorganic insulating films that can be used include silicon nitride film, silicon oxynitride film, silicon oxide film, silicon nitride oxide film, aluminum oxide film, and aluminum nitride film. Alternatively, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film may also be used. Furthermore, two or more of the above insulating films may be laminated together.

[0390] An organic insulating layer is preferred for the insulating layer 214, which functions as a planarizing layer. Examples of materials that can be used for the organic insulating layer include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. Alternatively, the insulating layer 214 may have a laminated structure of an organic insulating layer and an inorganic insulating layer. The outermost layer of the insulating layer 214 preferably functions as an etching protection layer. This makes it possible to suppress the formation of depressions in the insulating layer 214 during processing of conductive layers 112a, 126a, or 129a. Alternatively, depressions may be provided in the insulating layer 214 during processing of conductive layers 112a, 126a, or 129a.

[0391] Transistors 201 and 205 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0392] The transistor structure of the display device of this embodiment is not particularly limited. For example, vertical transistors, planar transistors, fin-type transistors, staggered transistors, inverse staggered transistors, etc., can be used. Furthermore, either a top-gate or bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below the semiconductor layer in which the channel is formed.

[0393] Transistors 201 and 205 are configured in which a semiconductor layer on which a channel is formed is sandwiched between two gates. The transistors may be driven by connecting the two gates and supplying them with the same signal. Alternatively, the threshold voltage of the transistors may be controlled by applying a potential to control the threshold voltage to one of the two gates and a potential to drive the other gate.

[0394] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, single-crystal semiconductors, or semiconductors with crystalline properties other than single crystals (microcrystalline semiconductors, polycrystalline semiconductors, or semiconductors with crystalline regions in part) may be used. Using a single-crystal semiconductor or a semiconductor with crystalline properties is preferable because it can suppress the degradation of transistor characteristics.

[0395] The semiconductor layer of the transistor preferably has a metal oxide (also called an oxide semiconductor). In other words, the display device of this embodiment preferably uses an OS transistor that uses a metal oxide in the channel formation region. For metal oxides that can be used in the OS transistor, refer to the description of Embodiment 2.

[0396] The transistors in circuit 164a and the transistors in the display unit 162 may have the same structure or different structures. The structures of the multiple transistors in circuit 164a may all be the same or there may be two or more different structures. Similarly, the structures of the multiple transistors in the display unit 162 may all be the same or there may be two or more different structures.

[0397] All of the transistors in the display unit 162 may be OS transistors, all of the transistors in the display unit 162 may be transistors using silicon in the channel formation region (hereinafter referred to as Si transistors), or some of the transistors in the display unit 162 may be OS transistors and the rest may be Si transistors.

[0398] Examples of silicon include single-crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, transistors having a low-temperature polysilicon (LTPS) semiconductor layer (hereinafter also referred to as LTPS transistors) can be used. LTPS transistors have high field-effect mobility and good frequency characteristics.

[0399] By using Si transistors such as LTPS transistors, circuits that need to be driven at high frequencies (e.g., source driver circuits) can be fabricated on the same board as the display unit. This simplifies the external circuits implemented in the display device, reducing component and mounting costs.

[0400] For example, by using both LTPS transistors and OS transistors in the display unit 162, a display device with low power consumption and high driving capability can be realized. Furthermore, a configuration combining LTPS transistors and OS transistors is sometimes referred to as LTPO. In a more preferable example, it is preferable to apply OS transistors to transistors that function as switches for controlling conduction and non-conduction between wiring, and LTPS transistors to transistors that control current.

[0401] For example, one of the transistors in the display unit 162 functions as a transistor for controlling the current flowing to the light-emitting device, and can also be called a drive transistor. One of the source and drain of the drive transistor is electrically connected to the pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor for this drive transistor. This makes it possible to increase the current flowing to the light-emitting device in the pixel circuit.

[0402] On the other hand, the other transistor in the display unit 162 functions as a switch for controlling the selection and deselection of pixels, and can also be called a selection transistor. The gate of the selection transistor is electrically connected to the gate line, and one of the source and drain is electrically connected to the source line (signal line). It is preferable to use an OS transistor for the selection transistor. This makes it possible to maintain the gradation of pixels even when the frame frequency is significantly reduced (e.g., 1 fps or less), and thus power consumption can be reduced by stopping the driver when displaying still images.

[0403] Thus, a display device according to one aspect of the present invention can combine a high aperture ratio, high resolution, high display quality, and low power consumption.

[0404] Furthermore, one embodiment of the present invention is a display device having an OS transistor and a light-emitting device with an MML (metal maskless) structure. This configuration makes it possible to extremely reduce the leakage current that can flow through the transistor and the leakage current that can flow between adjacent light-emitting devices (also called lateral leakage current or side leakage current). With this configuration, when an image is displayed on the display device, the observer can observe one or more of the following: image sharpness, image clarity, high saturation, and high contrast ratio. Moreover, by having an extremely low leakage current that can flow through the transistor and lateral leakage current between light-emitting devices, it is possible to achieve a display with as little light leakage (so-called black floating) that may occur when displaying black as possible.

[0405] In particular, among MML-structured light-emitting devices, applying the structure with subpixels of different emission colors as described above results in a configuration in which the layers provided between light-emitting devices (for example, an organic layer used in common between light-emitting devices, also called a common layer) are separated, thereby eliminating or significantly reducing side leakage current.

[0406] Figures 19(B) and (C) show other examples of transistor configurations that can be used for transistors 201 and 205.

[0407] Transistors 209 and 210 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer 231 having a channel forming region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel forming region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel forming region 231i. Furthermore, an insulating layer 218 covering the transistor may be provided.

[0408] In the transistor 209 shown in Figure 19(B), an example is shown where the insulating layer 225 covers the top and sides of the semiconductor layer 231. The conductive layers 222a and 222b are connected to the low-resistance region 231n through openings provided in the insulating layers 225 and 215, respectively. Of the conductive layers 222a and 222b, one functions as the source and the other as the drain.

[0409] On the other hand, in the transistor 210 shown in Figure 19(C), 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 Figure 19(C) can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In Figure 19(C), an insulating layer 215 is provided covering the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and conductive layer 222b are connected to the low-resistance region 231n, respectively, through openings in the insulating layer 215.

[0410] A connection portion 204 is provided in the region of substrate 151 where substrate 152 does not overlap. At the connection portion 204, wiring 165 is electrically connected to FPC 172a via conductive layer 166 and connection layer 242. The conductive layer 166 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as conductive layers 112a, 112b, and 112d, a conductive film obtained by processing the same conductive film as conductive layers 126a, 126b, and 126d, and a conductive film obtained by processing the same conductive film as conductive layers 129a, 129b, and 129d. On the upper surface of the connection portion 204, the conductive layer 166 is exposed. This allows the connection portion 204 and FPC 172a to be electrically connected via the connection layer 242.

[0411] It is preferable to provide a light-shielding layer 135 on the surface of the substrate 152 that faces the substrate 151. The light-shielding layer 135 can be provided between adjacent light-emitting devices and in the circuit 164a, etc. In addition, various optical components can be arranged on the outside of the substrate 152.

[0412] Materials that can be used for substrate 120 can be applied to substrate 151 and substrate 152, respectively.

[0413] As the connecting layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), etc., can be used.

[0414] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0415] (Embodiment 8) This embodiment describes a light-emitting device that can be used in a display device according to one aspect of the present invention.

[0416] As shown in Figure 20(A), the light-emitting device has an EL layer 763 between a pair of electrodes (lower electrode 761 and upper electrode 762). The EL layer 763 can be composed of multiple layers, such as layer 780, light-emitting layer 771, and layer 790.

[0417] The light-emitting layer 771 has at least a light-emitting substance (also called a light-emitting material).

[0418] When the lower electrode 761 is the anode and the upper electrode 762 is the cathode, layer 780 has one or more of the following: a layer containing a material with high hole injection properties (hole injection layer), a layer containing a material with high hole transport properties (hole transport layer), and a layer containing a material with high electron blocking properties (electron blocking layer). Similarly, layer 790 has one or more of the following: a layer containing a material with high electron injection properties (electron injection layer), a layer containing a material with high electron transport properties (electron transport layer), and a layer containing a material with high hole blocking properties (hole blocking layer). When the lower electrode 761 is the cathode and the upper electrode 762 is the anode, layers 780 and 790 have the opposite configurations to those described above.

[0419] A configuration having a layer 780, an emissive layer 771, and a layer 790 provided between a pair of electrodes can function as a single emissive unit, and in this specification, the configuration shown in Figure 20(A) is referred to as a single structure.

[0420] Furthermore, Figure 20(B) shows a modified example of the EL layer 763 of the light-emitting device shown in Figure 20(A). Specifically, the light-emitting device shown in Figure 20(B) has a layer 781 on the lower electrode 761, a layer 782 on the layer 781, a light-emitting layer 771 on the layer 782, a layer 791 on the light-emitting layer 771, a layer 792 on the layer 791, and an upper electrode 762 on the layer 792.

[0421] When the lower electrode 761 is the anode and the upper electrode 762 is the cathode, for example, layer 781 can be a hole injection layer, layer 782 a hole transport layer, layer 791 an electron transport layer, and layer 792 an electron injection layer. Also, when the lower electrode 761 is the cathode and the upper electrode 762 is the anode, layer 781 can be an electron injection layer, layer 782 an electron transport layer, layer 791 a hole transport layer, and layer 792 a hole injection layer. By using such a layer structure, carriers can be efficiently injected into the light-emitting layer 771, and the efficiency of carrier recombination within the light-emitting layer 771 can be increased.

[0422] As shown in Figures 20(C) and 20(D), a configuration in which multiple light-emitting layers (light-emitting layers 771, 772, and 773) are provided between layer 780 and layer 790 is also a variation of the single structure. Although Figures 20(C) and 20(D) show an example with three light-emitting layers, the light-emitting layers in a single-structure light-emitting device may be two layers or four or more layers. Furthermore, a single-structure light-emitting device may have a buffer layer between the two light-emitting layers.

[0423] Furthermore, as shown in Figures 20(E) and 20(F), a configuration in which multiple light-emitting units (light-emitting units 763a and 763b) are connected in series via a charge generation layer 785 (also called an intermediate layer) is referred to as a tandem structure in this specification. The tandem structure may also be called a stacked structure. By using a tandem structure, a light-emitting device capable of high-brightness emission can be created. In addition, compared to a single structure, the tandem structure can reduce the current required to obtain the same brightness, thereby improving reliability.

[0424] Figures 20(D) and 20(F) show examples in which the display device has a layer 764 that overlaps with the light-emitting device. Figure 20(D) shows an example in which layer 764 overlaps with the light-emitting device shown in Figure 20(C), and Figure 20(F) shows an example in which layer 764 overlaps with the light-emitting device shown in Figure 20(E).

[0425] Layer 764 can be either a color conversion layer or a color filter (coloring layer), or both.

[0426] In Figures 20(C) and 20(D), the light-emitting layers 771, 772, and 773 may be made of light-emitting materials that emit light of the same color, or even the same light-emitting material. For example, light-emitting materials that emit blue light may be used for the light-emitting layers 771, 772, and 773. In subpixels that emit blue light, the blue light emitted by the light-emitting device can be extracted. In subpixels that emit red light and subpixels that emit green light, a color conversion layer is provided as layer 764 as shown in Figure 20(D), which converts the blue light emitted by the light-emitting device into longer wavelength light, allowing for the extraction of red or green light.

[0427] Furthermore, different light-emitting materials with different emission colors may be used for each of the light-emitting layers 771, 772, and 773. When the light emitted by each of the light-emitting layers 771, 772, and 773 is complementary in color, white light emission is obtained. For example, a single-structure light-emitting device preferably has a light-emitting layer having a light-emitting material that emits blue light, and a light-emitting layer having a light-emitting material that emits visible light with a longer wavelength than blue.

[0428] For example, if a single-structure light-emitting device has three light-emitting layers, it is preferable that it has a light-emitting layer having a light-emitting material that emits red (R) light, a light-emitting layer having a light-emitting material that emits green (G) light, and a light-emitting layer having a light-emitting material that emits blue (B) light. The stacking order of the light-emitting layers can be R, G, B from the anode side, or R, B, G from the anode side, etc. In this case, a buffer layer may be provided between R and G or B.

[0429] Furthermore, for example, when a single-structure light-emitting device has two light-emitting layers, a configuration is preferred in which one light-emitting layer has a light-emitting material that emits blue (B) light, and the other light-emitting layer has a light-emitting material that emits yellow (Y) light. This configuration may be referred to as a BY single structure.

[0430] A color filter may be provided as layer 764, as shown in Figure 20(D). By passing white light through the color filter, light of the desired color can be obtained.

[0431] A light-emitting device that emits white light preferably contains two or more types of light-emitting materials. To obtain white light emission, one should select light-emitting materials such that the light emitted by each of the two or more materials is complementary in color. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary, a light-emitting device that emits white light as a whole can be obtained. The same applies to light-emitting devices that have three or more light-emitting layers.

[0432] Furthermore, in Figures 20(E) and 20(F), the light-emitting layer 771 and the light-emitting layer 772 may be made of light-emitting materials that emit light of the same color, or even the same light-emitting material.

[0433] For example, in a light-emitting device having subpixels that emit light of each color, light-emitting materials that emit blue light may be used in the light-emitting layer 771 and the light-emitting layer 772, respectively. In the subpixels that emit blue light, the blue light emitted by the light-emitting device can be extracted. In addition, in the subpixels that emit red light and the subpixels that emit green light, a color conversion layer is provided as layer 764 as shown in Figure 20(F), which converts the blue light emitted by the light-emitting device into longer wavelength light, allowing red or green light to be extracted.

[0434] Furthermore, when using light-emitting devices with the configuration shown in Figure 20(E) or Figure 20(F) for sub-pixels that emit light of each color, different light-emitting materials may be used for each sub-pixel. Specifically, in a light-emitting device for a sub-pixel that emits red light, light-emitting materials that emit red light may be used for both the light-emitting layer 771 and the light-emitting layer 772. Similarly, in a light-emitting device for a sub-pixel that emits green light, light-emitting materials that emit green light may be used for both the light-emitting layer 771 and the light-emitting layer 772. In a light-emitting device for a sub-pixel that emits blue light, light-emitting materials that emit blue light may be used for both the light-emitting layer 771 and the light-emitting layer 772. A display device with such a configuration employs a tandem structure of light-emitting devices, enabling high-brightness emission and achieving high reliability.

[0435] Furthermore, in Figures 20(E) and 20(F), different luminescent materials with different emission colors may be used for the luminescent layer 771 and the luminescent layer 772. When the light emitted by the luminescent layer 771 and the light emitted by the luminescent layer 772 are complementary colors, white light emission is obtained. A color filter may be provided as layer 764 as shown in Figure 20(F). By passing white light through the color filter, light of a desired color can be obtained.

[0436] In Figures 20(E) and 20(F), examples are shown in which the light-emitting unit 763a has one light-emitting layer 771 and the light-emitting unit 763b has one light-emitting layer 772, but the design is not limited to this. The light-emitting unit 763a and the light-emitting unit 763b may each have two or more light-emitting layers.

[0437] Furthermore, while Figures 20(E) and 20(F) illustrate a light-emitting device having two light-emitting units, the device is not limited to this. A light-emitting device may have three or more light-emitting units.

[0438] Specifically, the configuration of the light-emitting device shown in Figures 21(A) to 21(C) is an example.

[0439] Figure 21(A) shows a configuration with three light-emitting units. A configuration with two light-emitting units may also be referred to as a two-stage tandem structure, and a configuration with three light-emitting units may be referred to as a three-stage tandem structure.

[0440] Furthermore, as shown in Figure 21(A), the configuration is such that multiple light-emitting units (light-emitting unit 763a, light-emitting unit 763b, and light-emitting unit 763c) are connected in series via a charge generation layer 785. In addition, light-emitting unit 763a has layer 780a, light-emitting layer 771, and layer 790a, light-emitting unit 763b has layer 780b, light-emitting layer 772, and layer 790b, and light-emitting unit 763c has layer 780c, light-emitting layer 773, and layer 790c.

[0441] In the configuration shown in Figure 21(A), it is preferable that the light-emitting layers 771, 772, and 773 each have a light-emitting material that emits light of the same color. Specifically, the configuration can be such that the light-emitting layers 771, 772, and 773 each have a red (R) light-emitting material (a so-called R\R\R three-stage tandem structure), the light-emitting layers 771, 772, and 773 each have a green (G) light-emitting material (a so-called G\G\G three-stage tandem structure), or the light-emitting layers 771, 772, and 773 each have a blue (B) light-emitting material (a so-called B\B\B three-stage tandem structure).

[0442] The light-emitting materials that each emit light of the same color are not limited to the above configuration. For example, as shown in Figure 21(B), a tandem-type light-emitting device may be used in which multiple light-emitting units having multiple light-emitting materials are stacked. Figure 21(B) shows a configuration in which multiple light-emitting units (light-emitting unit 763a and light-emitting unit 763b) are connected in series via a charge generation layer 785. Light-emitting unit 763a has a layer 780a, light-emitting layers 771a, 771b, and 771c, and a layer 790a, while light-emitting unit 763b has a layer 780b, light-emitting layers 772a, 772b, and 772c, and a layer 790b.

[0443] In the configuration shown in Figure 21(B), the light-emitting layers 771a, 771b, and 771c are configured to emit white light (W) by selecting light-emitting materials that are complementary in color. Furthermore, the light-emitting layers 772a, 772b, and 772c are configured to emit white light (W) by selecting light-emitting materials that are complementary in color. That is, the configuration shown in Figure 21(C) is a two-stage tandem structure of W\W. There are no particular limitations on the stacking order of the complementary light-emitting materials in the light-emitting layers 771a, 771b, and 771c. The implementer can select the optimal stacking order as appropriate. Although not shown, a three-stage tandem structure of W\W\W, or a tandem structure of four or more stages, may also be used.

[0444] Furthermore, when using a tandem light-emitting device, there are two-stage tandem structures: B\Y having a light-emitting unit that emits yellow (Y) light and a light-emitting unit that emits blue (B) light; R·G\B having a light-emitting unit that emits red (R) and green (G) light and a light-emitting unit that emits blue (B) light; and a light-emitting unit that emits blue (B) light, a light-emitting unit that emits yellow (Y) light, and a light-emitting unit that emits blue (B) light. Examples include a B\Y\B three-stage tandem structure having a light-emitting unit that emits blue (B) light, a light-emitting unit that emits yellow-green (YG) light, and a light-emitting unit that emits blue (B) light in that order, and a B\YG\B three-stage tandem structure having a light-emitting unit that emits blue (B) light, a light-emitting unit that emits green (G) light, and a light-emitting unit that emits blue (B) light in that order.

[0445] Furthermore, as shown in Figure 21(C), a light-emitting unit having one light-emitting material and a light-emitting unit having multiple light-emitting materials may be combined.

[0446] Specifically, in the configuration shown in Figure 21(C), multiple light-emitting units (light-emitting units 763a, 763b, and 763c) are connected in series via a charge generation layer 785. Furthermore, light-emitting unit 763a has layer 780a, light-emitting layer 771, and layer 790a; light-emitting unit 763b has layer 780b, light-emitting layer 772a, light-emitting layer 772b, light-emitting layer 772c, and layer 790b; and light-emitting unit 763c has layer 780c, light-emitting layer 773, and layer 790c.

[0447] For example, in the configuration shown in Figure 21(C), a three-stage tandem structure of B\R·G·YG\B can be applied, where light-emitting unit 763a is a light-emitting unit that emits blue (B) light, light-emitting unit 763b is a light-emitting unit that emits red (R), green (G), and yellow-green (YG) light, and light-emitting unit 763c is a light-emitting unit that emits blue (B) light.

[0448] For example, the number of layers and color order of the light-emitting unit can be, from the anode side, a two-layer structure of B and Y, a two-layer structure of B and light-emitting unit X, a three-layer structure of B, Y, B, or a three-layer structure of B, X, B. The number of layers and color order of the light-emitting layers in light-emitting unit X can be, from the anode side, a two-layer structure of R and Y, a two-layer structure of R and G, a two-layer structure of G and R, a three-layer structure of G, R, G, or a three-layer structure of R, G, R. In addition, other layers may be provided between the two light-emitting layers.

[0449] In addition, in Figures 20(C) and 20(D), as shown in Figure 20(B), layer 780 and layer 790 may each be independently constructed as a laminated structure consisting of two or more layers.

[0450] Furthermore, in Figures 20(E) and 20(F), the light-emitting unit 763a has layer 780a, light-emitting layer 771, and layer 790a, and the light-emitting unit 763b has layer 780b, light-emitting layer 772, and layer 790b.

[0451] When the lower electrode 761 is the anode and the upper electrode 762 is the cathode, layers 780a and 780b each have one or more of the following: a hole injection layer, a hole transport layer, and an electron blocking layer. Similarly, layers 790a and 790b each have one or more of the following: an electron injection layer, an electron transport layer, and a hole blocking layer. When the lower electrode 761 is the cathode and the upper electrode 762 is the anode, layers 780a and 790a have the opposite configurations to those described above, and layers 780b and 790b also have the opposite configurations to those described above.

[0452] When the lower electrode 761 is the anode and the upper electrode 762 is the cathode, for example, layer 780a has a hole injection layer and a hole transport layer on the hole injection layer, and may further have an electron blocking layer on the hole transport layer. Also, layer 790a has an electron transport layer and may further have a hole blocking layer between the light-emitting layer 771 and the electron transport layer. Also, layer 780b has a hole transport layer and may further have an electron blocking layer on the hole transport layer. Also, layer 790b has an electron transport layer and an electron injection layer on the electron transport layer, and may further have a hole blocking layer between the light-emitting layer 772 and the electron transport layer. When the lower electrode 761 is the cathode and the upper electrode 762 is the anode, for example, layer 780a has an electron injection layer and an electron transport layer on the electron injection layer, and may further have a hole blocking layer on the electron transport layer. Furthermore, layer 790a may have a hole transport layer and an electron blocking layer between the light-emitting layer 771 and the hole transport layer. Also, layer 780b may have an electron transport layer and an electron blocking layer on the electron transport layer. Furthermore, layer 790b may have a hole transport layer and a hole injection layer on the hole transport layer, and an electron blocking layer between the light-emitting layer 772 and the hole transport layer.

[0453] Furthermore, when fabricating a tandem light-emitting device, the two light-emitting units are stacked with a charge generation layer 785 in between. The charge generation layer 785 has at least a charge generation region. The charge generation layer 785 has the function of injecting electrons into one of the two light-emitting units and holes into the other when a voltage is applied between the pair of electrodes.

[0454] Next, we will describe materials that can be used in light-emitting devices.

[0455] Of the lower electrode 761 and upper electrode 762, the electrode that extracts light preferably uses a conductive film that transmits visible light. Furthermore, it is preferable to use a conductive film that reflects visible light on the electrode that does not extract light. In addition, if the display device has a light-emitting device that emits infrared light, it is preferable to use a conductive film that transmits both visible light and infrared light on the electrode that extracts light, and a conductive film that reflects both visible light and infrared light on the electrode that does not extract light.

[0456] Furthermore, a conductive film that transmits visible light may also be used on the electrode that does not extract light. In this case, it is preferable to place the electrode between the reflective layer and the EL layer 763. In other words, the light emitted from the EL layer 763 may be reflected by the reflective layer and extracted from the display device.

[0457] As materials for forming a pair of electrodes in a light-emitting device, metals, alloys, electrically conductive compounds, and mixtures thereof can be used as appropriate. Specifically, such materials include metals such as aluminum, titanium, chromium, manganese, iron, cobalt, nickel, copper, gallium, zinc, indium, tin, molybdenum, tantalum, tungsten, palladium, gold, platinum, silver, yttrium, and neodymium, and alloys containing these in appropriate combinations. Other examples of such materials include indium tin oxide (In-Sn oxide, also called ITO), In-Si-Sn oxide (also called ITSO), indium zinc oxide (In-Zn oxide), and In-W-Zn oxide. Furthermore, examples of such materials include aluminum-containing alloys (aluminum alloys) such as aluminum, nickel, and lanthanum alloys (Al-Ni-La), and silver, palladium, and copper alloys (Ag-Pd-Cu, also written as APC). Other materials include elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (e.g., lithium, cesium, calcium, strontium), rare earth metals such as europium and ytterbium, alloys containing these in appropriate combinations, graphene, and the like.

[0458] It is preferable that the light-emitting device has a microcavity structure. Therefore, it is preferable that one of the pair of electrodes in the light-emitting device is a semitransmitting / semi-reflective electrode that is transparent to and reflective to visible light, and the other is a reflective electrode that is reflective to visible light. By having a microcavity structure in the light-emitting device, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby strengthening the light emitted from the light-emitting device.

[0459] Furthermore, the semi-transparent / semi-reflective electrode can have a laminated structure consisting of a conductive layer that can be used as a reflective electrode and a conductive layer that can be used as an electrode that transmits visible light (also called a transparent electrode).

[0460] The light transmittance of the transparent electrode shall be 40% or more. For example, it is preferable to use an electrode with a transmittance of 40% or more for visible light (light with a wavelength of 400 nm or more and less than 750 nm) for the transparent electrode of a light-emitting device. The visible light reflectance of the semi-transparent / semi-reflective electrode shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes shall be 1 × 10⁻⁶ -2 A value of Ωcm or less is preferable.

[0461] A light-emitting device has at least a light-emitting layer. Furthermore, a light-emitting device may have layers other than the light-emitting layer, including materials with high hole injection properties, materials with high hole transport properties, hole-blocking materials, materials with high electron transport properties, electron-blocking materials, materials with high electron injection properties, or bipolar materials (materials with high electron and hole transport properties). For example, a light-emitting device can have a configuration that includes, in addition to the light-emitting layer, one or more layers from among a hole injection layer, a hole transport layer, a hole-blocking layer, a charge generation layer, an electron-blocking layer, an electron transport layer, and an electron injection layer.

[0462] The light-emitting device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0463] The light-emitting layer contains one or more types of light-emitting materials. The light-emitting materials may include those exhibiting colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, or red. Furthermore, materials emitting near-infrared light may also be used as light-emitting materials.

[0464] Examples of luminescent materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0465] 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.

[0466] Examples of phosphorescent materials include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton; organometallic complexes (especially iridium complexes) using phenylpyridine derivatives having electron-withdrawing groups as ligands; platinum complexes; and rare earth metal complexes.

[0467] The light-emitting layer may contain one or more types of organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). One or more types of organic compounds may include materials with high hole transport properties (hole transport materials) and / or materials with high electron transport properties (electron transport materials). As the hole transport material, one of the materials with high hole transport properties that can be used in the hole transport layer, as described later, may be used. As the electron transport material, one of the materials with high electron transport properties that can be used in the electron transport layer, as described later, may be used. Furthermore, one or more types of organic compounds may include bipolar materials or TADF materials.

[0468] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting device.

[0469] The hole injection layer is a layer that injects holes from the anode into the hole transport layer, and is a layer containing a material with high hole injection capabilities. Examples of materials with high hole injection capabilities include aromatic amine compounds and composite materials containing hole transport materials and acceptor materials (electron-accepting materials).

[0470] As the hole-transporting material, a material with high hole-transporting properties that can be used in the hole-transporting layer, as described later, can be used.

[0471] As acceptor materials, for example, oxides of metals belonging to groups 4 through 8 of the periodic table can be used. Specifically, these include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is particularly preferred because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle. Organic acceptor materials containing fluorine can also be used. Furthermore, organic acceptor materials such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives can also be used.

[0472] For example, as a material with high hole injection properties, a material containing a hole transport material and an oxide of a metal belonging to Group 4 to Group 8 of the periodic table (typically molybdenum oxide) may be used.

[0473] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light-emitting layer. The hole transport layer is a layer containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having a hole mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport. Preferred hole transport materials include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.) and aromatic amines (compounds having an aromatic amine skeleton), which are materials with high hole transport capabilities.

[0474] The electron blocking layer is provided in contact with the light-emitting layer. The electron blocking layer is a layer containing a material that has hole-transporting properties and is capable of blocking electrons. Among the hole-transporting materials mentioned above, a material that has electron-blocking properties can be used for the electron blocking layer.

[0475] Because electron-blocking layers possess hole-transporting properties, they can also be called hole-transporting layers. Furthermore, among hole-transporting layers, those that exhibit electron-blocking properties can also be called electron-blocking layers.

[0476] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. The electron transport layer is a layer containing an electron-transporting material. The electron-transporting material is 1 × 10⁻¹⁶ -6 cm 2Materials having an electron mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes. Examples of electron-transporting 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, 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 π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds.

[0477] The hole-blocking layer is provided in contact with the light-emitting layer. The hole-blocking layer is a layer containing a material that has electron-transporting properties and is capable of blocking holes. Among the electron-transporting materials mentioned above, a material that has hole-blocking properties can be used for the hole-blocking layer.

[0478] Because hole-blocking layers possess electron-transporting properties, they can also be called electron-transporting layers. Furthermore, among electron-transporting layers, those that exhibit hole-blocking properties can also be called hole-blocking layers.

[0479] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer, and is a layer containing a material with high electron injection capabilities. Alkali metals, alkaline earth metals, or compounds thereof can be used as materials with high electron injection capabilities. Composite materials containing both electron transport materials and donor materials (electron-donating materials) can also be used as materials with high electron injection capabilities.

[0480] Furthermore, it is preferable that the LUMO level of a material with high electron injection capacity has a small difference (specifically, 0.5 eV or less) from the work function value of the material used as the cathode.

[0481] The electron injection layer contains, for example, lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), and calcium fluoride (CaF). x (where x is any number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatritium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatritium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatritium (abbreviation: LiPPP), lithium oxide (LiO x Alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. The electron injection layer may also be a multilayer structure of two or more layers. For example, a multilayer structure in which lithium fluoride is used as the first layer and ytterbium is provided as the second layer can be used.

[0482] The electron injection layer may contain an electron-transporting material. For example, a compound having a lone pair of electrons and an electron-deficient heteroaromatic ring can be used as the electron-transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), or a triazine ring can be used.

[0483] Furthermore, the lowest unoccupied molecular orbital (LUMO) level of organic compounds with lone pairs of electrons is preferably between -3.6 eV and -2.3 eV. In general, the highest occupied molecular orbital (HOMO) level and LUMO level of organic compounds can be estimated by methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy.

[0484] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds containing lone pairs of electrons. NBPhen has a higher glass transition temperature (Tg) and superior heat resistance compared to BPhen.

[0485] As described above, the charge generation layer has at least a charge generation region. The charge generation region preferably contains an acceptor material, and preferably contains, for example, a hole transport material and an acceptor material applicable to the hole injection layer described above.

[0486] Furthermore, the charge generation layer preferably includes a layer containing a material with high electron injection potential. This layer can also be called an electron injection buffer layer. The electron injection buffer layer is preferably provided between the charge generation region and the electron transport layer. By providing an electron injection buffer layer, the injection barrier between the charge generation region and the electron transport layer can be relaxed, allowing electrons generated in the charge generation region to be easily injected into the electron transport layer.

[0487] The electron injection buffer layer preferably contains an alkali metal or an alkaline earth metal, and can, for example, a compound of an alkali metal or an alkaline earth metal. Specifically, the electron injection buffer layer preferably has an inorganic compound containing an alkali metal and oxygen, or an inorganic compound containing an alkaline earth metal and oxygen, and more preferably has an inorganic compound containing lithium and oxygen (such as lithium oxide (Li2O)). In addition, any other material applicable to the electron injection layer can be suitably used for the electron injection buffer layer.

[0488] The charge generation layer preferably has a layer containing a material with high electron transport properties. This layer can also be called an electron relay layer. The electron relay layer is preferably provided between the charge generation region and the electron injection buffer layer. If the charge generation layer does not have an electron injection buffer layer, the electron relay layer is preferably provided between the charge generation region and the electron transport layer. The electron relay layer has the function of preventing interaction between the charge generation region and the electron injection buffer layer (or electron transport layer) and smoothly transferring electrons.

[0489] As the electron relay layer, it is preferable to use a phthalocyanine-based material such as copper(II) phthalocyanine (abbreviated as CuPc), or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0490] Furthermore, the charge generation region, electron injection buffer layer, and electron relay layer described above may not be clearly distinguishable depending on their cross-sectional shape or characteristics.

[0491] The charge generation layer may have a donor material instead of an acceptor material. For example, the charge generation layer may have a layer containing an electron transport material and a donor material, which is applicable to the electron injection layer described above.

[0492] When stacking light-emitting units, the rise in driving voltage can be suppressed by providing a charge generation layer between the two light-emitting units.

[0493] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0494] (Embodiment 9) This embodiment describes a light-receiving device and a display device having light-receiving and light-receiving functions that can be used in a display device according to one aspect of the present invention.

[0495] For example, a pn-type or pin-type photodiode can be used as the light-receiving device. The light-receiving device functions as a photoelectric conversion device (also called a photoelectric conversion element) that detects light incident on it and generates an electric charge. The amount of charge generated from the light-receiving device is determined by the amount of light incident on it.

[0496] In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light-receiving device. Organic photodiodes can be easily made thinner, lighter, and larger in area, and because they offer a high degree of freedom in shape and design, they can be applied to various display devices.

[0497] [Light receiving device] As shown in Figure 22(A), the photodetector has a layer 765 between a pair of electrodes (lower electrode 761 and upper electrode 762). The layer 765 has at least one active layer and may have other layers.

[0498] Furthermore, Figure 22(B) shows a modified example of the layer 765 of the photodetector shown in Figure 22(A). Specifically, the photodetector shown in Figure 22(B) has a layer 766 on the lower electrode 761, an active layer 767 on the layer 766, a layer 768 on the active layer 767, and an upper electrode 762 on the layer 768.

[0499] The active layer 767 functions as a photoelectric conversion layer.

[0500] When the lower electrode 761 is the anode and the upper electrode 762 is the cathode, layer 766 has one or both of a hole transport layer and an electron blocking layer. Similarly, layer 768 has one or both of an electron transport layer and a hole blocking layer. When the lower electrode 761 is the cathode and the upper electrode 762 is the anode, layers 766 and 768 have the opposite configurations to those described above.

[0501] In one embodiment of the present invention, there may be layers that are common to both the light-receiving device and the light-emitting device (which can also be described as a continuous layer shared by both the light-receiving device and the light-emitting device). Such layers may have different functions in the light-emitting device and the light-receiving device. In this specification, components may be referred to based on their function in the light-emitting device. For example, a hole injection layer functions as a hole injection layer in the light-emitting device and as a hole transport layer in the light-receiving device. Similarly, an electron injection layer functions as an electron injection layer in the light-emitting device and as an electron transport layer in the light-receiving device. Furthermore, layers common to both the light-receiving device and the light-emitting device may have the same function in both the light-receiving device and the light-receiving device. For example, a hole transport layer functions as a hole transport layer in both the light-receiving device and the light-receiving device, and an electron transport layer functions as an electron transport layer in both the light-receiving device and the light-receiving device.

[0502] Next, we will describe the materials that can be used in light-receiving devices.

[0503] The light-receiving device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-receiving device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0504] The active layer of a light-receiving device includes a semiconductor. Examples of such semiconductors include inorganic semiconductors such as silicon, and organic semiconductors containing organic compounds. In this embodiment, an example is shown in which an organic semiconductor is used as the semiconductor of the active layer. Using an organic semiconductor is preferable because the light-emitting layer and the active layer can be formed using the same method (for example, vacuum deposition), and the manufacturing equipment can be shared.

[0505] As for the n-type semiconductor material of the active layer, fullerene (for example, C 60 , C 70Examples include electron-accepting organic semiconductor materials such as fullerene derivatives. Examples of fullerene derivatives include [6,6]-Phenyl-C 71 -butyric acid methyl ester (abbreviation: PC70BM), [6,6]-Phenyl-C 61 -butyric acid methyl ester (abbreviation: PC60BM), 1',1'',4',4''-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2'',3''][5,6]fulrerene-C 60 Examples include (abbreviated as ICBA).

[0506] Furthermore, examples of n-type semiconductor materials include perylenetetracarboxylic acid derivatives such as N,N'-dimethyl-3,4,9,10-perylenetetracarboxylic acid diimide (abbreviated as Me-PTCDI), and 2,2'-(5,5'-(thieno[3,2-b]thiophene-2,5-diyl)bis(thiophene-5,2-diyl))bis(methane-1-yl-1-ylidene)dimalonitrile (abbreviated as FT2TDMN).

[0507] 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.

[0508] Examples of p-type semiconductor materials for the active layer include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin phthalocyanine (SnPc), quinacridone, and rubrene.

[0509] Furthermore, examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, and compounds having an aromatic amine skeleton. In addition, 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, rubrene derivatives, tetracene derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives.

[0510] The HOMO level of electron-donating organic semiconductor materials is preferably shallower (higher) than the HOMO level of electron-accepting organic semiconductor materials. The LUMO level of electron-donating organic semiconductor materials is preferably shallower (higher) than the LUMO level of electron-accepting organic semiconductor materials.

[0511] It is preferable to use spherical fullerenes as electron-accepting organic semiconductor materials and organic semiconductor materials with a near-planar shape as electron-donating organic semiconductor materials. Molecules with similar shapes tend to aggregate, and when molecules of the same type aggregate, their molecular orbital energy levels are close, which can improve carrier transport.

[0512] Furthermore, the active layer can use polymer compounds such as Poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c']dithiophene-1,3-diyl]]polymer (abbreviated as PBDB-T) or PBDB-T derivatives, which function as donors. For example, a method of dispersing the acceptor material in PBDB-T or a PBDB-T derivative can be used.

[0513] The active layer is preferably formed by co-depositing an n-type semiconductor and a p-type semiconductor. Alternatively, the active layer may be formed by stacking an n-type semiconductor and a p-type semiconductor.

[0514] Furthermore, the active layer may be a mixture of three or more materials. To broaden the wavelength range, a third material may be mixed in addition to the n-type semiconductor material and the p-type semiconductor material. In this case, the third material may be a low-molecular-weight compound or a high-molecular-weight compound.

[0515] The photodetector may further include layers other than the active layer, such as a material with high hole transport properties, a material with high electron transport properties, or a bipolar material (a material with high electron and hole transport properties). Furthermore, it may also further include layers containing a material with high hole injection properties, a hole blocking material, a material with high electron injection properties, or an electron blocking material. For example, the layers other than the active layer of the photodetector can be made of materials that can be used in the light-emitting devices described above.

[0516] Polymeric compounds such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS), and inorganic compounds such as molybdenum oxide and copper iodide (CuI) can be used as hole transporting materials or electron blocking materials. Furthermore, inorganic compounds such as zinc oxide (ZnO) and organic compounds such as polyethyleneimine ethoxylate (PEIE) can be used as electron transporting materials or hole blocking materials. The light-receiving device may, for example, have a mixed film of PEIE and ZnO.

[0517] [Display device with light detection function] A display device according to one aspect of the present invention has a display unit in which light-emitting devices are arranged in a matrix, and an image can be displayed on the display unit. Furthermore, light-receiving devices are arranged in a matrix on the display unit, and the display unit has an image display function, as well as one or both of an imaging function and a sensing function. The display unit can be used as an image sensor or a touch sensor. In other words, by detecting light on the display unit, an image can be captured, or the proximity or contact of an object (such as a finger, hand, or pen) can be detected. That is, a display device having a light-receiving device can function as a touch panel.

[0518] Furthermore, in one embodiment of the present invention, the light-emitting device can be used as the light source for the sensor. In one embodiment of the present invention, when an object reflects (or scatters) the light emitted by the light-emitting device of the display unit, the light-receiving device can detect the reflected light (or scattered light), thus enabling imaging or touch detection even in dark places.

[0519] Therefore, it is not necessary to provide a light receiving unit and a light source separately from the display device, and the number of components in the electronic device can be reduced. For example, there is no need to separately provide a biometric authentication device or a capacitive touch panel for scrolling, etc., which are provided in the electronic device. Therefore, by using a display device according to one aspect of the present invention, it is possible to provide an electronic device with reduced manufacturing costs.

[0520] Specifically, a display device according to one aspect of the present invention has a light-emitting device and a light-receiving device in each pixel. In a display device according to one aspect of the present invention, an organic EL device is used as the light-emitting device and an organic photodiode is used as the light-receiving device. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display device using an organic EL device.

[0521] In a display device having light-emitting and light-receiving devices in its pixels, the pixels have a light-receiving function, allowing for the detection of contact or proximity of an object while displaying an image. For example, not only can the display device display an image using all of its subpixels, but some subpixels can also emit light as a light source while the remaining subpixels display an image.

[0522] When a light-receiving device is used as an image sensor, the display device can capture an image using the light-receiving device. For example, the display device of this embodiment can be used as a scanner.

[0523] For example, an image sensor can be used to capture images for personal authentication, such as fingerprints, palm prints, irises, pulse patterns (including vein and artery patterns), or faces.

[0524] For example, an image sensor can be used to image the area around the eyes, the surface of the eyes, or the inside of the eyes (such as the fundus) of the wearable device user. Therefore, the wearable device can be equipped with the ability to detect one or more of the user's blinking, pupil movement, and eyelid movement.

[0525] Furthermore, the light-receiving device can be used as a touch sensor (also called a direct touch sensor) or a near-touch sensor (also called a hover sensor, hover-touch sensor, non-contact sensor, or touchless sensor).

[0526] Here, the touch sensor or near-touch sensor can detect the proximity or contact of an object (such as a finger, hand, or pen).

[0527] A touch sensor can detect an object by making direct contact with the display device. A near-touch sensor can detect an object even if the object does not touch the display device. For example, it is preferable that the display device can detect an object when the distance between the display device and the object is in the range of 0.1 mm to 300 mm, preferably 3 mm to 50 mm. With this configuration, it becomes possible to operate the display device without the object directly touching it, in other words, it becomes possible to operate the display device without contact (touchless). With the above configuration, the risk of the display device becoming dirty or scratched can be reduced, or it becomes possible to operate the display device without the object directly touching any dirt (e.g., dust or viruses) attached to the display device.

[0528] Furthermore, a display device according to one aspect of the present invention can have a variable refresh rate. For example, power consumption can be reduced by adjusting the refresh rate according to the content displayed on the display device (for example, within a range of 1 Hz to 240 Hz). In addition, the drive frequency of the touch sensor or near touch sensor may be changed according to the refresh rate. For example, if the refresh rate of the display device is 120 Hz, the drive frequency of the touch sensor or near touch sensor can be set to a frequency higher than 120 Hz (typically 240 Hz). This configuration makes it possible to achieve low power consumption and to increase the response speed of the touch sensor or near touch sensor.

[0529] Furthermore, in a display device according to one aspect of the present invention, a lens can be provided on the light-receiving device. By making the width of the lens larger than the width of the light-receiving portion, the light-collecting ability can be increased, and the light sensitivity of the light-receiving device can be improved.

[0530] The display device 100 shown in Figures 22(C) to (E) has a layer 353 having a light-receiving device, a functional layer 355, and a layer 357 having a light-emitting device between substrate 351 and substrate 359.

[0531] The functional layer 355 includes circuits for driving a light-receiving device and circuits for driving a light-emitting device. The functional layer 355 may include one or more of the following: switches, transistors, capacitors, resistors, wiring, and terminals. However, when the light-emitting device and light-receiving device are driven in a passive matrix manner, the configuration may be made without switches and transistors.

[0532] For example, as shown in Figure 22(C), in layer 357 which has a light-emitting device, the light emitted by the light-emitting device is reflected by the finger 352 that is in contact with the display device 100, and the light-receiving device in layer 353 which has a light-receiving device detects the reflected light. This makes it possible to detect that the finger 352 has come into contact with the display device 100.

[0533] Furthermore, as shown in Figures 22(D) and (E), the device may also have a function to detect or image objects that are close to (but not in contact with) the display device. Figure 22(D) shows an example of detecting a person's finger, and Figure 22(E) shows an example of detecting information around, on the surface of, or inside a person's eye (such as the number of blinks, eyeball movements, and eyelid movements).

[0534] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0535] (Embodiment 10) In this embodiment, an electronic device according to one aspect of the present invention will be described with reference to Figures 23(A) to 24(G).

[0536] The electronic device of this embodiment has a display device according to one aspect of the present invention in its display unit. The display device according to one aspect of the present invention is easily made high-definition and high-resolution. Therefore, it can be used in the display units of various electronic devices.

[0537] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as other electronic devices with relatively large screens, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, and audio playback devices.

[0538] A display device according to one aspect of the present invention preferably has an extremely high resolution such as HD (1280 x 720 pixels), FHD (1920 x 1080 pixels), WQHD (2560 x 1440 pixels), WQXGA (2560 x 1600 pixels), 4K (3840 x 2160 pixels), or 8K (7680 x 4320 pixels). A resolution of 4K, 8K, or higher is particularly preferred. Furthermore, there are no particular limitations on the aspect ratio of the display device according to one aspect of the present invention. For example, the display device can support various aspect ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0539] The electronic device of this embodiment may have sensors (including those with the function of detecting, detecting, or measuring force, displacement, position, velocity, acceleration, angular velocity, rotational 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 radiation).

[0540] The electronic device of this embodiment can have a variety of functions. For example, it can have a function to display various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function to display a calendar, date or time, a function to execute various software (programs), a wireless communication function, a function to read programs or data recorded on a recording medium, and so on.

[0541] The electronic device 6500 shown in Figure 23(A) is a portable information terminal that can be used as a smartphone.

[0542] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0543] A display device according to one embodiment of the present invention can be applied to the display unit 6502. Because the aperture ratio of the pixels can be increased, the light extraction efficiency is high and an extremely bright image can be displayed.

[0544] Figure 23(B) is a schematic cross-sectional view of the housing 6501 including the end on the microphone 6506 side.

[0545] A light-transmitting protective member 6510 is provided on the display side of the housing 6501, and the display panel 6511, optical component 6512, touch panel 6513, printed circuit board 6517, battery 6518, etc. are arranged in the space enclosed by the housing 6501 and the protective member 6510.

[0546] The protective member 6510 is fixed to the display panel 6511, the optical member 6512, and the touch panel 6513 by an adhesive layer (not shown). The function of the touch panel can also be performed by a light-receiving device in one embodiment of the present invention. The light-receiving device in one embodiment of the present invention has a configuration that detects light through a lens, has high light sensitivity, and has excellent touch position detection capability. Furthermore, the light-receiving device can also acquire images for fingerprint authentication.

[0547] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and the FPC 6515 is connected to this folded portion. IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on the printed circuit board 6517.

[0548] A flexible display according to one embodiment of the present invention can be applied to the display panel 6511. This makes it possible to realize an extremely lightweight electronic device. Furthermore, because the display panel 6511 is extremely thin, it is possible to incorporate a large-capacity battery 6518 while keeping the thickness of the electronic device low. In addition, by folding back a part of the display panel 6511 and placing the connection part with the FPC 6515 on the back of the pixel area, it is possible to realize an electronic device with a narrow bezel.

[0549] Figure 23(C) shows an example of a television system. The television system 7100 has a display unit 7000 incorporated into a housing 7101. Here, the housing 7101 is shown supported by a stand 7103.

[0550] A display device according to one embodiment of the present invention can be applied to the display unit 7000. Because the display device according to one embodiment of the present invention can increase the aperture ratio of the pixels, it has high light extraction efficiency and can display an extremely bright image.

[0551] The television device 7100 shown in Figure 23(C) can be operated using the operation switches on the housing 7101 and a separate remote control unit 7111. Alternatively, the display unit 7000 may be equipped with a touch sensor, and the television device 7100 can be operated by touching the display unit 7000 with a finger or the like. The remote control unit 7111 may have a display unit that displays information output from the remote control unit 7111. Channels and volume can be controlled and the image displayed on the display unit 7000 can be controlled using the operation keys or touch panel on the remote control unit 7111.

[0552] The television system 7100 is configured to include a receiver and a modem. The receiver can receive general television broadcasts. Furthermore, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0553] Figure 23(D) shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0554] A display device according to one embodiment of the present invention can be applied to the display unit 7000. Because the display device according to one embodiment of the present invention can increase the aperture ratio of the pixels, it has high light extraction efficiency and can display an extremely bright image.

[0555] Figures 23(E) and (F) show examples of digital signage.

[0556] The digital signage 7300 shown in Figure 23(E) comprises a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0557] Figure 23(F) shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 has a display unit 7000 that is provided along the curved surface of the column 7401.

[0558] In Figures 23(E) and (F), a display device according to one embodiment of the present invention can be applied to the display unit 7000. Because the display device according to one embodiment of the present invention can increase the aperture ratio of the pixels, it has high light extraction efficiency and can display an extremely bright image.

[0559] The larger the display area 7000, the more information can be provided at once. Furthermore, a larger display area 7000 is more eye-catching, which can, for example, enhance the effectiveness of advertising.

[0560] 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 operate it intuitively. Furthermore, when used for purposes such as providing route information or traffic information, intuitive operation can enhance usability. The touch panel can also be configured as a light-receiving device of a display device according to one aspect of the present invention. The light-receiving device of a display device according to one aspect of the present invention has a configuration that detects light through a lens and has high light sensitivity. Therefore, it is possible to create a touch panel with high sensitivity and excellent touch position detection capability.

[0561] Furthermore, as shown in Figures 23(E) and (F), it is preferable that the digital signage 7300 or digital signage 7400 can be linked wirelessly with an information terminal 7311 or information terminal 7411 such as a smartphone owned by the user. For example, the advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or information terminal 7411. In addition, the display on the display unit 7000 can be switched by operating the information terminal 7311 or information terminal 7411.

[0562] Furthermore, the digital signage 7300 or digital signage 7400 can be used to run games using the screen of the information terminal 7311 or information terminal 7411 as the control device (controller). This allows an unspecified number of users to participate in and enjoy the game simultaneously.

[0563] The electronic equipment shown in Figures 24(A) to (G) includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), connection terminals 9006, sensors 9007 (including functions for detecting, detecting, or measuring force, displacement, position, velocity, acceleration, angular velocity, rotational 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 radiation), a microphone 9008, etc.

[0564] The electronic devices shown in Figures 24(A) to (G) have various functions. For example, they may have functions to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date or time, a function to control processing by various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. However, the functions of electronic devices are not limited to these and can have various functions. Electronic devices may have multiple display units. Furthermore, electronic devices may be equipped with a camera, etc., and have functions to capture still images or videos and save them to a recording medium (external or built into the camera), a function to display the captured images on a display unit, etc.

[0565] Details of the electronic devices shown in Figures 24(A) to (G) will be described below. A display device according to one embodiment of the present invention can be applied to these electronic devices. Because the display device according to one embodiment of the present invention can have a high pixel aperture ratio, it has high light extraction efficiency and can display extremely bright images. Furthermore, these electronic devices can have touch panel functionality. This touch panel functionality can also be performed by a light-receiving device in the display device according to one embodiment of the present invention. The light-receiving device in the display device according to one embodiment of the present invention has a configuration that detects light through a lens, and is characterized by high light sensitivity and excellent touch position detection capability. Furthermore, the light-receiving device can also acquire images for fingerprint authentication.

[0566] Figure 24(A) is a perspective view showing a personal digital information terminal (PDI) 9101. The PDI 9101 can be used, for example, as a smartphone. The PDI 9101 may also be equipped with a speaker 9003, connection terminals 9006, sensors 9007, etc. The PDI 9101 can also display text and image information on multiple surfaces. Figure 24(A) shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the subject of an email or SNS message, the sender's name, date and time, time, battery level, signal strength, etc. Alternatively, icons 9050, etc., may be displayed in the position where the information 9051 is displayed.

[0567] Figure 24(B) is a perspective view showing the personal digital assistant (PDA) 9102. The PDA 9102 has the 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. The user can also check information 9053, which is displayed in a position that can be observed from above the PDA 9102, while the PDA 9102 is stored in the breast pocket of their clothing. The user can check the display and decide whether or not to answer a call without taking the PDA 9102 out of their pocket.

[0568] Figure 24(C) is a perspective view showing the tablet terminal 9103. The tablet terminal 9103 can run various applications, such as mobile phone calls, email, document viewing and creation, music playback, internet communication, and computer games. The tablet terminal 9103 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the housing 9000. The left side of the housing 9000 has operation keys 9005 as buttons for operation, and the bottom has connection terminals 9006.

[0569] Figure 24(D) is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can be used, for example, as a smartwatch (registered trademark). The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. The personal information terminal 9200 can also make hands-free calls by communicating with a wireless communication headset. Furthermore, the personal information terminal 9200 can transmit data to other information terminals and be charged via a connection terminal 9006. Charging may be performed by wireless power supply.

[0570] Figures 24(E) to (G) are perspective views showing a foldable portable information terminal 9201. Figure 24(E) shows the portable information terminal 9201 in an unfolded state, Figure 24(G) shows it in a folded state, and Figure 24(F) shows a state in between, transitioning from one of Figures 24(E) or 24(G) to the other. The portable information terminal 9201 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state. The display unit 9001 of the portable 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 to 150 mm.

[0571] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part. [Explanation of Symbols]

[0572] 10 pixels 11 subpixels 12 subpixels 13-pixel array 14 circuits 15 circuits 16 circuits 17 CDS circuit 18 circuits 19 circuits 20 circuits 21 A / D conversion circuit 22 circuits 23 Comparator 24 IOS 30 Display device 100A display device 100T transistor 100 display device 101 layers 102 circuit boards 104e conductive layer 104 Conductive layer 105 Conductive layer 106 Insulating layer 107a Insulating layer 107b Insulating layer 107c insulating layer 107 Insulating layer 108 Semiconductor layer 109 Insulating layer 110a subpixel 110b subpixel 110c sub-pixel 110d sub-pixel 110e subpixel 110 pixels 111c pixel electrode 111d Pixel electrode 112a conductive layer 112a_1 Conductive layer 112a_2 Conductive layer 112b Conductive layer 112d conductive layer 113_1 Light-emitting unit 113_2 Light-emitting unit 113_3 Charge generation layer 113c layer 113d layer 114 Common layer 115 Conductive layer 116 Conductive layer 117 Common electrode 118c mask layer 118d mask layer 120 circuit boards 122 Adhesive layer 125 Insulating layer 126a conductive layer 126b Conductive layer 126d conductive layer 127 Insulating layer 128 layers 129a conductive layer 129b Conductive layer 129d conductive layer 130c light-emitting device 130G Light-emitting Device 130R Light-emitting Device 131 Protective layer 135 Light blocking layer 137 Colored layer 141a aperture 141b Aperture 141 Aperture 142 Aperture 144a aperture 144b aperture 150P light receiving device 150 light receiving devices 151 circuit boards 152 circuit boards 162 Display section 164a Circuit 164b Circuit 164 circuits 165a Wiring 165b Wiring 165 Wiring 166 Conductive layer 167 circuits 172a FPC 172b FPC 173a IC chip 173b IC chip 201 Transistors 204 Connection part 205 transistors 206 transistors 209 transistors 210 transistors 211 Insulating layer 213 Insulating layer 214 Insulating layer 215 Insulating layer 218 Insulating layer 221 Conductive layer 222a conductive layer 222b Conductive layer 223 Conductive layer 225 Insulating layer 231i Channel formation region 231n Low resistance region 231 Semiconductor layer 242 Connecting Layers 255a Insulating layer 255b Insulating layer 255c insulating layer 351 circuit board 352 fingers 353 layers 355 Functional Layers 357 layers 359 circuit boards 761 Lower electrode 762 Upper electrode 763a Light-emitting unit 763b Light-emitting unit 763c Light-emitting unit 763 EL layer 764 layers 765 layers 766 layers 767 Active layer 768 layers 771a Light-emitting layer 771b Emitting layer 771c luminescent layer 771 Emitting layer 772a Light-emitting layer 772b Emitting layer 772c luminescent layer 772 Emitting layer 773 Emitting layer 780a layer 780b layer 780c layer 780 layers 781 layers 782 layers 785 Charge generation layer 790a layer 790b layer 790c layer 790 layers 791 layers 792 layers 6500 Electronic equipment 6501 enclosure 6502 Display section 6503 Power button 6504 button 6505 Speaker 6506 Mike 6507 Camera 6508 Light source 6510 Protective component 6511 Display Panel 6512 Optical components 6513 Touch Panel 6515 FPC 6516 IC 6517 Printed circuit board 6518 Battery 7000 Display 7100 Television equipment 7101 enclosure 7103 Stand 7111 Remote Control Unit 7200 Notebook Personal Computer 7211 enclosure 7212 Keyboard 7213 Pointing device 7214 External connection port 7300 Digital Signage 7301 enclosure 7303 Speaker 7311 Information terminal 7400 Digital Signage 7401 pillars 7411 Information terminal 9000 cabinets 9001 Display section 9002 Camera 9003 Speaker 9005 Operation Keys 9006 Connection terminal 9007 Sensor 9008 Microphone 9050 Icon 9051 Information 9052 Information 9053 Information 9054 Information 9055 Hinge 9101 Mobile Information Terminal 9102 Mobile Information Terminal 9103 Tablet device 9200 Mobile Information Terminal 9201 Mobile Information Terminal

Claims

1. A resistor voltage divider circuit is provided. The resistive voltage divider circuit is a semiconductor device having a transistor, a first conductive layer, a second conductive layer, a first insulating layer, a third conductive layer, a semiconductor layer, a second insulating layer, and a fourth conductive layer on a substrate; the second conductive layer has a region in contact with an upper surface of the first conductive layer and has a first opening; the first insulating layer has a region in contact with an upper surface of the second conductive layer and a region in contact with an upper surface of the first conductive layer, and has a second opening; the third conductive layer has a region in contact with an upper surface of the first insulating layer and has a third opening; the first opening, the second opening, and the third opening overlap each other; the semiconductor layer has a region in contact with the first conductive layer inside the first opening, a region along a sidewall of the second opening, and a region along a sidewall of the third opening; the second insulating layer has a region in contact with an upper surface of the semiconductor layer, the fourth conductive layer has a region in contact with an upper surface of the second insulating layer, an upper surface of the semiconductor layer has a first recess that reflects the second opening and the third opening; an upper surface of the second insulating layer has a second recess that reflects the first recess; the fourth conductive layer has a region embedded in the second recess, the first conductive layer and the second conductive layer function as one of a source electrode and a drain electrode of a transistor, the third conductive layer functions as the other of the source electrode and the drain electrode of the transistor, the semiconductor layer has a channel formation region of the transistor, the fourth conductive layer functions as a gate electrode of the transistor.

2. A resistor voltage divider circuit is provided. The resistive voltage divider circuit is a semiconductor device having a transistor, a first conductive layer, a second conductive layer, a first insulating layer, a third conductive layer, a semiconductor layer, a second insulating layer, and a fourth conductive layer on a substrate; the second conductive layer has a region in contact with an upper surface of the first conductive layer and has a first opening; the first insulating layer has a region in contact with an upper surface of the second conductive layer and a region in contact with an upper surface of the first conductive layer, and has a second opening; the third conductive layer has a region in contact with an upper surface of the first insulating layer and has a third opening; the first opening, the second opening, and the third opening overlap each other; the semiconductor layer has a region in contact with the first conductive layer inside the first opening, a region along a sidewall of the second opening, and a region along a sidewall of the third opening; the second insulating layer has a region in contact with an upper surface of the semiconductor layer, the fourth conductive layer has a region in contact with an upper surface of the second insulating layer, an upper surface of the semiconductor layer has a first recess that reflects the second opening and the third opening; an upper surface of the second insulating layer has a second recess that reflects the first recess; the fourth conductive layer has a region embedded in the second recess, the first conductive layer and the second conductive layer function as one of a source electrode and a drain electrode of a transistor, the third conductive layer functions as the other of the source electrode and the drain electrode of the transistor, the semiconductor layer has a channel formation region of the transistor, the fourth conductive layer functions as a gate electrode of the transistor, The semiconductor layer has a region that does not overlap with the fourth conductive layer and does not overlap with the third conductive layer.

3. A resistor voltage divider circuit is provided. The resistive voltage divider circuit is a semiconductor device having a transistor, a first conductive layer, a second conductive layer, a first insulating layer, a third conductive layer, a semiconductor layer, a second insulating layer, a fourth conductive layer, and a third insulating layer on a substrate; the second conductive layer has a region in contact with an upper surface of the first conductive layer and has a first opening; the first insulating layer has a region in contact with an upper surface of the second conductive layer and a region in contact with an upper surface of the first conductive layer, and has a second opening; the third conductive layer has a region in contact with an upper surface of the first insulating layer and has a third opening; the first opening, the second opening, and the third opening overlap each other; the semiconductor layer has a region in contact with the first conductive layer inside the first opening, a region along a sidewall of the second opening, and a region along a sidewall of the third opening; the third insulating layer has a region that contacts the top surface of the semiconductor layer inside the second opening, the second insulating layer has a region that contacts the top surface of the semiconductor layer inside the second opening, the fourth conductive layer has a region in contact with an upper surface of the second insulating layer, an upper surface of the semiconductor layer has a first recess that reflects the second opening and the third opening; an upper surface of the second insulating layer has a second recess that reflects the first recess; the fourth conductive layer has a region embedded in the second recess, the first conductive layer and the second conductive layer function as one of a source electrode and a drain electrode of a transistor, the third conductive layer functions as the other of the source electrode and the drain electrode of the transistor, the semiconductor layer has a channel formation region of the transistor, the fourth conductive layer functions as a gate electrode of the transistor.

4. A resistor voltage divider circuit is provided. The resistive voltage divider circuit is a semiconductor device having a transistor, a first conductive layer, a second conductive layer, a first insulating layer, a third conductive layer, a semiconductor layer, a second insulating layer, a fourth conductive layer, and a third insulating layer on a substrate; the second conductive layer has a region in contact with an upper surface of the first conductive layer and has a first opening; the first insulating layer has a region in contact with an upper surface of the second conductive layer and a region in contact with an upper surface of the first conductive layer, and has a second opening; the third conductive layer has a region in contact with an upper surface of the first insulating layer and has a third opening; the first opening, the second opening, and the third opening overlap each other; the semiconductor layer has a region in contact with the first conductive layer inside the first opening, a region along a sidewall of the second opening, and a region along a sidewall of the third opening; the third insulating layer has a region that contacts the top surface of the semiconductor layer inside the second opening, the second insulating layer has a region that contacts the top surface of the semiconductor layer inside the second opening, the fourth conductive layer has a region in contact with an upper surface of the second insulating layer, an upper surface of the semiconductor layer has a first recess that reflects the second opening and the third opening; an upper surface of the second insulating layer has a second recess that reflects the first recess; the fourth conductive layer has a region embedded in the second recess, the first conductive layer and the second conductive layer function as one of a source electrode and a drain electrode of a transistor, the third conductive layer functions as the other of the source electrode and the drain electrode of the transistor, the semiconductor layer has a channel formation region of the transistor, the fourth conductive layer functions as a gate electrode of the transistor, The semiconductor layer has a region that does not overlap with the fourth conductive layer and does not overlap with the third conductive layer.

5. In any one of claims 1 to 4, The semiconductor device, wherein the semiconductor layer comprises indium oxide.

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