Display device and electronic equipment

Abstract

A display device with high definition is provided. A small display device is provided. A display device having a first layer and a second layer stacked thereon. The first layer includes a gate drive circuit and a source drive circuit, and the second layer includes a display unit. The gate drive circuit and the source drive circuit are arranged in a manner having an area overlapping the display unit. In addition, the gate drive circuit and the source drive circuit are not clearly separated and have areas overlapping each other. Five or more gate drive circuits and source drive circuits can be arranged.

Description

Technical Field

[0001] One embodiment of the present invention relates to a display device, an operating method thereof, and an electronic device. One embodiment of the present invention relates to a method for manufacturing a display device. One embodiment of the present invention relates to a transistor and a method for manufacturing a transistor.

[0002] Note that one embodiment of the present invention is not limited to the above-mentioned technical field. Examples of the technical field of one embodiment of the present invention disclosed in this specification and the like include semiconductor devices, display devices, light-emitting devices, power storage devices, storage devices, electronic devices, lighting devices, input devices, input-output devices, and methods for driving or manufacturing these devices. Semiconductor devices refer to all devices that can work by utilizing semiconductor characteristics. Background Art

[0003] As a semiconductor material that can be used for transistors, oxide semiconductors using metal oxides have attracted attention. For example, Patent Document 1 discloses a semiconductor device in which a plurality of oxide semiconductor layers are stacked, in which an oxide semiconductor layer used as a channel contains indium and gallium, and the content ratio of indium is higher than the content ratio of gallium, so that field effect mobility (sometimes referred to as mobility or μFE) is improved.

[0004] Since the metal oxide that can be used for the semiconductor layer can be formed by sputtering or the like, it can be used for the semiconductor layer of the transistor constituting the large display device. In addition, since part of the production equipment of the transistor using polycrystalline silicon or amorphous silicon can be improved and used, the equipment investment can also be suppressed. In addition, compared with the transistor using amorphous silicon, the transistor using metal oxide has a high field effect mobility, so a high-function display device provided with a driver circuit can be realized.

[0005] In addition, as display devices for augmented reality (AR) or virtual reality (VR), wearable display devices and fixed display devices are becoming increasingly popular. As wearable display devices, for example, there are head mounted displays (HMD) or glasses-type display devices. As fixed display devices, for example, there are head-up displays (HUD).

[0006] Furthermore, a digital camera or the like, which is an electronic device having an image pickup device, is provided with a viewfinder for checking an image to be taken before shooting, and the viewfinder uses an electronic viewfinder. The electronic viewfinder is provided with a display unit, and the image taken by the image pickup device can be displayed as an image on the display unit. For example, Patent Document 2 discloses an electronic viewfinder that can continuously obtain good visibility from the center of the image to the edge of the image.

[0007] [Prior technical literature]

[0008] [Patent Document]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2014-7399

[0010] [Patent Document 2] Japanese Patent Application Publication No. 2012-42569 Summary of the invention

[0011] Technical problem to be solved by the invention

[0012] Display devices whose display surfaces are close to the user, such as head-mounted displays (HMDs), have the following problems: users can more easily see pixels and may feel a strong sense of graininess, which sometimes weakens the immersion or presence of AR or VR. In addition, like the optical viewfinder, the electronic viewfinder includes an eyepiece portion, and the user's eyes approach the eyepiece portion to confirm the image displayed on the display portion of the electronic viewfinder. Therefore, the display portion of the electronic viewfinder is close to the user. As a result, the user can easily see the pixels set in the display portion and may feel a strong sense of graininess. In view of this, as HMDs and electronic viewfinders, display devices with fine pixels are required. For example, the pixel density is preferably greater than 1000ppi, more preferably greater than 5000ppi, and further preferably greater than 10000ppi. In addition, for example, a display device particularly provided in an electronic viewfinder is preferably capable of displaying images with a resolution of 4K (3840×2160 pixels), 5K (5120×2880 pixels) or higher.

[0013] One of the purposes of one embodiment of the present invention is to provide a display device with a large number of pixels. Another purpose of one embodiment of the present invention is to provide a display device with high definition. Another purpose of one embodiment of the present invention is to provide a display device capable of displaying high-resolution images. Another purpose of one embodiment of the present invention is to provide a display device capable of displaying high-quality images. Another purpose of one embodiment of the present invention is to provide a display device capable of displaying images with a sense of presence. Another purpose of one embodiment of the present invention is to provide a display device capable of displaying high-brightness images. Another purpose of one embodiment of the present invention is to provide a display device with a high dynamic range. Another purpose of one embodiment of the present invention is to provide a display device with a narrow frame. Another purpose of one embodiment of the present invention is to provide a small display device. Another purpose of one embodiment of the present invention is to provide a display device operating at high speed. Another purpose of one embodiment of the present invention is to provide a display device with low power consumption. Another purpose of one embodiment of the present invention is to provide an inexpensive display device. Another purpose of one embodiment of the present invention is to provide a display device with high reliability. Another purpose of one embodiment of the present invention is to provide a novel display device. Another purpose of one embodiment of the present invention is to provide a novel method for operating a display device. Another purpose of one embodiment of the present invention is to provide a novel electronic device.

[0014] Note that the description of these purposes does not prevent the existence of other purposes. Note that one embodiment of the present invention does not necessarily achieve all of the above purposes. In addition, purposes other than the above may be derived from the description of the specification, drawings, claims, etc.

[0015] Solutions to technical problems

[0016] One embodiment of the present invention is a display device having a first layer and a second layer stacked thereon, wherein the first layer includes a gate driving circuit and a source driving circuit, and the second layer includes a display unit, in which pixels are arranged in a matrix, the gate driving circuit and the source driving circuit have areas overlapping with the pixels, and the gate driving circuit has an area overlapping with the source driving circuit.

[0017] In addition, in the above-mentioned manner, the display device may further include a DA conversion circuit, the DA conversion circuit including a potential generating circuit and a transfer transistor logic circuit, the potential generating circuit being arranged outside the source driving circuit, the transfer transistor logic circuit being arranged in the source driving circuit, the potential generating circuit having a function of generating a plurality of potentials of different sizes from each other, and the transfer transistor logic circuit having a function of receiving image data and outputting any one of the potentials generated by the potential generating circuit according to the digital value of the image data.

[0018] In the above embodiment, the pixel may include a transistor including a metal oxide in the channel formation region, and the metal oxide may include an element M (M is Al, Ga, Y, or Sn) and Zn.

[0019] In addition, one embodiment of the present invention is a display device having a first layer and a second layer stacked thereon, the first layer including a gate driving circuit, a first source driving circuit, a second source driving circuit, a third source driving circuit, a fourth source driving circuit and a fifth source driving circuit, the second layer including a first display unit, a second display unit, a third display unit, a fourth display unit and a fifth display unit, in the first display unit, the first pixels are arranged in a matrix, in the second display unit, the second pixels are arranged in a matrix, in the third display unit, the third pixels are arranged in a matrix, in the fourth display unit, the fourth pixels are arranged in a matrix, and in the fifth display unit, the fifth pixels are arranged in a matrix, the gate driving circuit and the first source driving circuit have an area overlapping with the first pixel, the second source driving circuit has an area overlapping with the second pixel, the third source driving circuit has an area overlapping with the third pixel, the fourth source driving circuit has an area overlapping with the fourth pixel, the fifth source driving circuit has an area overlapping with the fifth pixel, and the gate driving circuit has an area overlapping with the first source driving circuit.

[0020] In addition, in the above manner, the display device may also include a DA conversion circuit, the DA conversion circuit includes a potential generating circuit, a first transfer transistor logic circuit, a second transfer transistor logic circuit, a third transfer transistor logic circuit, a fourth transfer transistor logic circuit and a fifth transfer transistor logic circuit, the potential generating circuit is arranged outside the first to fifth source driving circuits, the first transfer transistor logic circuit is arranged in the first source driving circuit, the second transfer transistor logic circuit is arranged in the second source driving circuit, the third transfer transistor logic circuit is arranged in the third source driving circuit, the fourth transfer transistor logic circuit is arranged in the fourth source driving circuit, and the fifth transfer transistor logic circuit is arranged in the fifth source driving circuit, the potential generating circuit has a function of generating multiple potentials of different sizes, and the first to fifth transfer transistor logic circuits have a function of receiving image data and outputting any one of the potentials generated by the potential generating circuit according to the digital value of the image data.

[0021] In the above embodiment, the first to fifth pixels may include transistors including a metal oxide in the channel formation region, and the metal oxide may include an element M (M is Al, Ga, Y, or Sn) and Zn.

[0022] In addition, one embodiment of the present invention is a display device having a first layer and a second layer stacked thereon, the first layer including a gate driving circuit and a source driving circuit, the second layer including a display unit, in which pixels are arranged in a matrix, the gate driving circuit and the source driving circuit have areas overlapping with the pixels, the gate driving circuit has an area overlapping with the source driving circuit, the source driving circuit is electrically connected to the pixel via a first data line, the source driving circuit is electrically connected to the pixel via a second data line, the source driving circuit has a function of generating a first image signal and supplying it to the pixel via the first data line, the source driving circuit has a function of generating a second image signal and supplying it to the pixel via the second data line, and the pixel has a function of displaying an image in which an image corresponding to the first image signal overlaps an image corresponding to the second image signal.

[0023] In addition, in the above-mentioned manner, the display device may further include a DA conversion circuit, the DA conversion circuit including a potential generating circuit and a transfer transistor logic circuit, the potential generating circuit being arranged outside the source driving circuit, the transfer transistor logic circuit being arranged in the source driving circuit, the potential generating circuit having a function of generating a plurality of potentials of different sizes from each other, and the transfer transistor logic circuit having a function of receiving image data and outputting any one of the potentials generated by the potential generating circuit according to the digital value of the image data.

[0024] Furthermore, in the above embodiment, the pixel may include a display element, and the display element may be a light-emitting element.

[0025] In the above embodiment, the display element may be an organic EL element.

[0026] In the above embodiment, the organic EL element may have a tandem structure.

[0027] In addition, in the above manner, the pixel includes a display element, a first transistor, a second transistor, a third transistor and a capacitor, one of the source and the drain of the first transistor is electrically connected to an electrode in the capacitor, the other of the source and the drain of the first transistor is electrically connected to the first data line, one of the source and the drain of the second transistor is electrically connected to the other electrode in the capacitor, the other of the source and the drain of the second transistor is electrically connected to the second data line, the other electrode in the capacitor is electrically connected to the gate of the third transistor, and one of the source and the drain of the third transistor is electrically connected to an electrode in the display element.

[0028] In the above embodiment, the first and second transistors may include a metal oxide in the channel formation region, and the metal oxide may include an element M (M is Al, Ga, Y, or Sn) and Zn.

[0029] Furthermore, an electronic device including the display device according to one embodiment of the present invention and a lens is also one embodiment of the present invention.

[0030] Effects of the Invention

[0031] According to one embodiment of the present invention, a display device having a large number of pixels can be provided. According to one embodiment of the present invention, a display device having high definition can be provided. According to one embodiment of the present invention, a display device capable of displaying a high-resolution image can be provided. According to one embodiment of the present invention, a display device capable of displaying a high-quality image can be provided. According to one embodiment of the present invention, a display device capable of displaying an image having a sense of presence can be provided. According to one embodiment of the present invention, a display device capable of displaying a high-brightness image can be provided. According to one embodiment of the present invention, a display device having a high dynamic range can be provided. According to one embodiment of the present invention, a display device having a narrow frame can be provided. According to one embodiment of the present invention, a small display device can be provided. According to one embodiment of the present invention, a display device operating at a high speed can be provided. According to one embodiment of the present invention, a display device having low power consumption can be provided. According to one embodiment of the present invention, an inexpensive display device can be provided. According to one embodiment of the present invention, a display device having high reliability can be provided. According to one embodiment of the present invention, a novel display device can be provided. According to one embodiment of the present invention, a novel operating method can be provided. According to one embodiment of the present invention, a novel electronic device can be provided.

[0032] Note that the description of these effects does not prevent the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of the above effects. In addition, effects other than the above can be derived from the description of the specification, drawings, claims, etc.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] [ Figure 1 ]A block diagram showing a structural example of a display device.

[0035] [ Figure 2 ]A block diagram showing a structural example of a display device.

[0036] [ Figure 3 ]A block diagram showing a structural example of a display device.

[0037] [ Figure 4 ]A block diagram showing a structural example of a display device.

[0038] [ Figure 5]A block diagram showing a structural example of a display device.

[0039] [ Figure 6 ]A block diagram showing a structural example of a display device.

[0040] [ Figure 7 ]A block diagram showing a structural example of a display device.

[0041] [ Figure 8 ]A block diagram showing a structural example of a display device.

[0042] [ Fig. 9 ]A circuit diagram showing a structural example of a DA conversion circuit.

[0043] [ Fig.10 ] is a block diagram showing a structural example of a shift register.

[0044] [Fig. 11] (A) A block diagram showing a structural example of a shift register. (B) A circuit diagram showing a structural example of a shift register.

[0045] [ Fig.12 ] shows a schematic diagram of the configuration of the gate drive circuit and the source drive circuit.

[0046] [ Fig.13 ] shows a top view of a structural example of a gate drive circuit and a source drive circuit.

[0047] [Figure 14] (A), (B), (C), (D), (E) are diagrams showing structural examples of pixels.

[0048] [Figure 15] (A), (B), (C) are circuit diagrams showing structural examples of pixels.

[0049] [Fig. 16] (A) A circuit diagram showing a structural example of a pixel. (B) A timing diagram showing an example of a method of operating a pixel. (C) and (D) Circuit diagrams showing structural examples of a pixel.

[0050] [Figure 17] (A), (B), (C), and (D) are circuit diagrams showing structural examples of pixels.

[0051] [ Fig.18 ]A block diagram showing a structural example of a display device.

[0052] [ Fig.19 ]A diagram illustrating an example of the operation of the display device.

[0053] [ Fig. 20 ]A cross-sectional view showing a structural example of a display device.

[0054] [ Fig.21 ]A cross-sectional view showing a structural example of a display device.

[0055] [ Fig. 22 ]A cross-sectional view showing a structural example of a display device.

[0056] [ Fig.23 ]A cross-sectional view showing a structural example of a display device.

[0057] [ Fig.24 ]A cross-sectional view showing a structural example of a display device.

[0058] [ Fig.25 ]A cross-sectional view showing a structural example of a display device.

[0059] [Figure 26] (A), (B), (C), (D), and (E) are diagrams showing structural examples of light-emitting elements.

[0060] [Fig. 27] (A) is a top view showing a structural example of a transistor. (B) and (C) are cross-sectional views showing a structural example of a transistor.

[0061] [Fig. 28] (A) is a top view showing a structural example of a transistor. (B) and (C) are cross-sectional views showing a structural example of a transistor.

[0062] [Fig. 29] (A) is a top view showing a structural example of a transistor. (B) and (C) are cross-sectional views showing a structural example of a transistor.

[0063] [Figure 30] (A), (B), (C), (D), and (E) are perspective views showing examples of electronic devices.

[0064] [Figure 31] (A), (B), (C), (D), (E), (F), and (G) are stereoscopic views showing examples of electronic devices.

[0065] [ Fig.32 ] is a diagram showing the measurement results of Id-Vd characteristics according to an embodiment.

[0066] [ Fig.33 ]A diagram showing the structure of a pixel according to an embodiment.

[0067] [ Fig.34 ]STEM image of a transistor according to an embodiment.

[0068] [Fig. 35] (A) and (B) are diagrams showing the measurement results of Id-Vd characteristics according to the embodiment.

[0069] Modes for Carrying Out the Invention

[0070] The following describes the embodiments with reference to the accompanying drawings. However, the embodiments can be implemented in a number of different ways, and a person skilled in the art can easily understand that the methods and details can be transformed into various forms without departing from the purpose and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the contents described in the embodiments shown below.

[0071] Note that in each of the drawings described in this specification, the size of each component, the thickness of a layer, and a region may be exaggerated for easy understanding.

[0072] The ordinal numbers such as “first”, “second” and “third” used in the present specification are provided to avoid confusion among constituent elements and are not intended to limit the number of constituent elements.

[0073] In this specification, for the sake of convenience, words and phrases indicating configuration such as "upper" and "lower" are used to describe the positional relationship of the components with reference to the drawings. In addition, the positional relationship of the components is appropriately changed according to the direction in which each component is described. Therefore, the words and phrases described in the specification are not limited, and the words and phrases can be appropriately changed according to the situation.

[0074] In addition, in this specification, the functions of the source and drain included in the transistor may be interchanged when the polarity of the transistor or the direction of current in circuit operation changes. Therefore, the terms "source" and "drain" may be interchanged.

[0075] In this specification, etc., "electrical connection" includes connection through "an element having some kind of electrical function". Here, "an element having some kind of electrical function" is not particularly limited as long as it can transmit and receive electrical signals between the connected objects. For example, "an element having some kind of electrical function" includes not only electrodes and wiring, but also switching elements such as transistors, resistors, inductors, capacitors, and other elements having various functions.

[0076] In addition, in this specification, the words "film" and "layer" may be interchanged. For example, the words "conductive layer" and "insulating layer" may be replaced with "conductive film" and "insulating film".

[0077] In addition, in this specification, etc., unless otherwise specified, the off-state current refers to the drain current when the transistor is in the off state (also called the non-conducting state or the blocking state). Unless otherwise specified, in an n-channel transistor, the off state refers to the voltage V between the gate and the source. gs Below the threshold voltage V th (In a p-channel transistor, V gsHigher than V th ) status.

[0078] In the accompanying drawings, the size, thickness of the layer or the area are sometimes exaggerated for the sake of clarity. Therefore, the present invention is not necessarily limited to the above-mentioned dimensions. In addition, in the accompanying drawings, ideal examples are schematically shown, so the present invention is not limited to the shapes or numerical values ​​shown in the accompanying drawings. For example, in the actual manufacturing process, layers or resist masks are sometimes unintentionally thinned due to treatments such as etching, but illustrations are sometimes omitted for ease of understanding. In addition, in the accompanying drawings, the same reference numerals are sometimes used in common between different drawings to represent the same parts or parts with the same functions and materials, etc., and their repeated descriptions are omitted. In addition, when representing parts with the same functions and materials, etc., the same hatching is sometimes used without adding special reference numerals.

[0079] In this specification, etc., metal oxide refers to an oxide of a metal in a broad sense. Metal oxides are classified into oxide insulators, oxide conductors (including transparent oxide conductors), and oxide semiconductors (also called oxide semiconductors or simply OS). For example, when a metal oxide is used in the active layer of a transistor, the metal oxide is sometimes referred to as an oxide semiconductor. In other words, an OS FET can be referred to as a transistor containing an oxide or an oxide semiconductor.

[0080] (Implementation Method 1)

[0081] In this embodiment, a display device which is one embodiment of the present invention is described.

[0082] One embodiment of the present invention relates to a display device having a first layer and a second layer stacked thereon. The first layer includes a gate drive circuit and a source drive circuit, and the second layer includes a display unit. The gate drive circuit and the source drive circuit are arranged in a manner having an area overlapping with the display unit. Thus, a display device of one embodiment of the present invention can be narrowed in frame and miniaturized.

[0083] In addition, the gate driving circuit and the source driving circuit are not clearly separated and have an overlapping area, thereby achieving a further narrow frame and miniaturization of the display device compared to a case where there is no overlapping area.

[0084] Here, in the case where the gate drive circuit and the source drive circuit do not overlap with the display unit, for example, the gate drive circuit and the source drive circuit are arranged in the periphery of the display unit. In this case, from the perspective of the location of the source drive circuit, etc., it is difficult to arrange a display unit with more than two rows and two columns. On the other hand, in a display device of one embodiment of the present invention, by arranging the gate drive circuit and the source drive circuit in a layer different from the layer in which the display unit is arranged, they can have an area overlapping with the display unit, thereby arranging a display unit with more than two rows and two columns. That is, more than five gate drive circuits and source drive circuits can be arranged in a display device of one embodiment of the present invention.

[0085] As described above, by means of a gate drive circuit and a source drive circuit having an area overlapping with the display portion, the display device can, for example, operate at a higher speed than a display device in which the gate drive circuit and the source drive circuit do not overlap with the display portion. Thus, the clarity of a display device of one embodiment of the present invention can be further improved compared to a display device in which the gate drive circuit and the source drive circuit do not overlap with the display portion. For example, the pixel density of a display device of one embodiment of the present invention can be set to more than 1000ppi, more than 5000ppi, or 10000ppi. In addition, the resolution of an image that can be displayed by a display device of one embodiment of the present invention can be further improved compared to a display device in which the gate drive circuit and the source drive circuit do not overlap with the display portion.

[0086] <Structural Example 1 of Display Device>

[0087] Figure 1 1 is a block diagram showing a structural example of a display device 10 as a display device of one embodiment of the present invention. The display device 10 includes a layer 20 and a layer 30 stacked on the layer 20. The layer 20 includes a gate drive circuit 21, a source drive circuit 22, and a circuit 40. The layer 30 includes a display unit 33, in which pixels 34 are arranged in a matrix. An interlayer insulating layer may be provided between the layer 20 and the layer 30. In addition, the layer 20 may be stacked on the layer 30.

[0088] The circuit 40 is electrically connected to the source driving circuit 22. In addition, the circuit 40 may be electrically connected to other circuits.

[0089] The pixels 34 in the same row are electrically connected to the gate driving circuit 21 through the wiring 31, and the pixels 34 in the same column are electrically connected to the source driving circuit 22 through the wiring 32. The wiring 31 functions as a scanning line, and the wiring 32 functions as a data line.

[0090] Although in Figure 1, a structure in which pixels 34 in a row are electrically connected via a wiring 31 and pixels 34 in a column are electrically connected via a wiring 32 is shown, but one embodiment of the present invention is not limited thereto. For example, pixels 34 in a row may be electrically connected via two or more wirings 31, and pixels 34 in a column may be electrically connected via two or more wirings 32. That is, for example, one pixel 34 may be electrically connected to two or more scan lines, and may be electrically connected to two or more data lines. In addition, for example, one wiring 31 may be electrically connected to pixels 34 in more than two rows, and one wiring 32 may be electrically connected to pixels 34 in more than two columns. That is, for example, one wiring 31 may be shared by pixels 34 in more than two rows, and one wiring 32 may be shared by pixels 34 in more than two columns.

[0091] The gate drive circuit 21 has a function of generating a signal for controlling the operation of the pixel 34 and supplying the signal to the pixel 34 through the wiring 31. The source drive circuit 22 has a function of generating an image signal and supplying the signal to the pixel 34 through the wiring 32. The circuit 40, for example, has a function of receiving image data as a basis for the image signal generated by the source drive circuit 22 and supplying the received image data to the source drive circuit 22. In addition, the circuit 40 has a function of a control circuit that generates a start pulse signal, a clock signal, etc. In addition, the circuit 40 may be a circuit having functions different from those of the gate drive circuit 21 and the source drive circuit 22.

[0092] The display unit 33 has a function of displaying an image corresponding to an image signal supplied from the source driving circuit 22 to the pixel 34. Specifically, the image is displayed on the display unit 33 by emitting light having a brightness corresponding to the image signal from the pixel 34.

[0093] exist Figure 1 In FIG. 1 , the positional relationship between the layer 20 and the layer 30 is indicated by a dashed line and a white circle, and the white circle of the layer 20 and the white circle of the layer 30 connected by the dashed line overlap each other. The same is also indicated in other drawings.

[0094] The display device 10 includes a region where the gate driver circuit 21 and the source driver circuit 22 provided in the layer 20 overlap with the display unit 33. For example, the gate driver circuit 21 and the source driver circuit 22 have a region overlapping with the pixel 34. By stacking the gate driver circuit 21 and the source driver circuit 22 and the display unit 33 in such a manner that the regions overlap with each other, the display device 10 can be made narrower in frame and smaller in size.

[0095] In addition, the gate drive circuit 21 and the source drive circuit 22 are not clearly separated and have an area that overlaps with each other. This area is the area 23. By having the area 23, the area occupied by the gate drive circuit 21 and the source drive circuit 22 can be reduced. Thus, even if the area of ​​the display portion 33 is small, the gate drive circuit 21 and the source drive circuit 22 can be set in a manner that does not exceed the display portion 33. In addition, the area where the gate drive circuit 21 and the source drive circuit 22 do not overlap with the display portion 33 can also be reduced. As described above, compared with the case where there is no area 23, narrow frame and miniaturization can be further achieved.

[0096] The circuit 40 may not overlap with the display portion 33 . Alternatively, the circuit 40 may have a region overlapping with the display portion 33 .

[0097] Figure 1 Although the structure example in which one gate driver circuit 21 and one source driver circuit 22 are provided in layer 20 and one display unit 33 is provided in layer 30 is shown, a plurality of display units 33 may be provided in layer 30. That is, the display unit provided in layer 30 may be divided. Figure 2 yes Figure 1 1 and 2. The structure of the display device 10 is modified as shown in FIG. 1 , and a structure example of the display device 10 is shown in which the display unit 33 is provided in three rows and three columns in the layer 30. In addition, the display unit 33 may be provided in two rows and two columns, or in four rows and four columns or more. In addition, the number of rows and columns of the display unit 33 provided in the layer 30 may be different from each other. Figure 2 In the display device 10 having the structure shown, for example, all the display units 33 can be used to display one image.

[0098] For easy understanding, Figure 2 Although the wiring 31 and the wiring 32 are omitted in the figure, in fact Figure 2 The display device 10 of the structure shown in the figure is provided with wiring 31 and wiring 32. Figure 2 Although the electrical connection relationship of the circuit 40 is omitted, the circuit 40 is actually electrically connected to the source driver circuit 22. Figure 2 Similarly, in other drawings, part of components and the like may be omitted.

[0099] For example, the same number of gate driver circuits 21 and source driver circuits 22 as the display unit 33 may be provided in the layer 20. In this case, the gate driver circuit 21 may be provided so as to overlap with the display unit 33 provided with the pixels 34 to which the gate driver circuit 21 supplies the signals. In addition, the source driver circuit 22 may be provided so as to overlap with the display unit 33 provided with the pixels 34 to which the source driver circuit 22 supplies the image signals.

[0100] By providing a plurality of display units 33, and providing a gate drive circuit 21 and a source drive circuit 22 according to the plurality of display units 33, the number of pixels 34 provided in one display unit 33 can be reduced. A plurality of gate drive circuits 21 can work in parallel, and a plurality of source drive circuits 22 can work in parallel, so that, for example, the time required to write an image signal corresponding to one frame of an image into a pixel 34 can be shortened. Thus, a frame period can be shortened, and high-speed operation of the display device 10 can be achieved. Therefore, the number of pixels 34 contained in the display device 10 can be increased to improve the resolution of the display device 10. In addition, the resolution of the image that can be displayed by the display device of one embodiment of the present invention can be further improved compared to a display device in which the gate drive circuit and the source drive circuit do not overlap with the display unit. Furthermore, the clock frequency can be reduced, thereby reducing the power consumption of the display device 10.

[0101] Here, in the case where the gate driver circuit and the source driver circuit do not overlap with the display unit, for example, the gate driver circuit and the source driver circuit are disposed at the periphery of the display unit. In this case, it is difficult to provide a display unit with more than two rows and two columns from the perspective of the location of the source driver circuit. On the other hand, in the display device 10, by providing the gate driver circuit and the source driver circuit in a layer different from the layer in which the display unit is provided, they can have an area overlapping with the display unit, thereby Figure 2 As shown in the figure, a display unit with more than two rows and two columns can be provided. In other words, more than five gate driving circuits and source driving circuits can be provided in the display device 10, respectively.

[0102] In summary, the display device 10 can operate at a higher speed, for example, than a display device in which the gate drive circuit and the source drive circuit do not overlap with the display portion. Thus, the clarity of the display device 10 can be further improved compared to a display device in which the gate drive circuit and the source drive circuit do not overlap with the display portion. For example, the pixel density of the display device 10 can be set to more than 1000ppi, more than 5000ppi, or 10000ppi. Therefore, the display device 10 can display high-quality images without graininess, and can display images with a sense of presence. Therefore, the display device 10 is particularly suitable for use in devices in which the display surface is close to the user, especially portable electronic devices, wearable electronic devices (wearable devices), and e-book reader terminals. In addition, it is suitable for use in VR devices and AR devices, etc. Furthermore, it is also suitable for use in viewfinders such as electronic viewfinders provided in digital cameras, etc., which are electronic devices having a camera device.

[0103] In addition, the resolution of the image that can be displayed by the display device 10 can be further improved compared to a display device in which the gate driving circuit and the source driving circuit do not overlap with the display portion. For example, when the display device 10 is applied to a viewfinder, the display device 10 can display images with a resolution of 4K, 5K or higher.

[0104] In addition, when a plurality of source driver circuits 22 and the like are provided in the layer 20 and a plurality of display units 33 are provided in the layer 30, Figure 1 The same is true for the case shown in FIG. 1 , where only one circuit 40 is provided in the display device 10. Figure 2 As shown, the circuit 40 may not overlap with any of the display portions 33. Alternatively, the circuit 40 may have a region overlapping with any of the display portions 33.

[0105] Although Figure 2 Although the configuration example in which the same number of gate driving circuits 21 as the number of display units 33 is provided is shown, one embodiment of the present invention is not limited to this. Figure 3 yes Figure 2 1 and 12 , and shows a configuration example of a display device 10 in which the same number of gate drive circuits 21 as the number of columns of the display unit 33 is provided. Figure 3 The display device 10 of the structure shown has three columns of display units 33, and therefore has three gate drive circuits 21. In addition, three rows of display units 33 are provided, and one gate drive circuit 21 is shared by the display units 33 in three rows and one column.

[0106] Figure 4 yes Figure 2 1 and 2. In addition, a modification example of the structure shown in FIG. 1 is shown, and a structural example of a display device 10 having a plurality of display units 33 and a gate drive circuit 21 is shown. Figure 4 In the display device 10 of the structure shown in FIG. 1 , the display units 33 of three rows and three columns share one gate drive circuit 21. Figure 4 In the display device 10 having the structure shown, the gate driving circuit 21 does not necessarily need to overlap with the display portion 33 .

[0107] In addition, although not shown, the number of source driver circuits 22 may not be the same as the number of display units 33. The number of source driver circuits 22 included in the display device 10 may be greater than the number of display units 33 provided in the display device 10, or may be less than the number of display units 33 provided in the display device 10.

[0108] Although Figure 1 Although the structural example in which the circuit 40 is provided in the layer 20 is shown, the circuit 40 may not be provided in the layer 20 . Figure 5 yes Figure 1The above is a modification of the structure shown, and shows an example of the structure of the display device 10 in which the circuit 40 is provided in the layer 30. Alternatively, the components of the circuit 40 may be provided in the layer 20 and the layer 30, respectively.

[0109] Although Figure 1 Although the configuration example in which one display unit 33 and one gate driving circuit are provided is shown, more gate driving circuits than the display unit 33 may be provided. Figure 6 yes Figure 1 The configuration shown is a modified example of the configuration, and shows an example of the configuration of the display device 10 in which two gate drive circuits (gate drive circuit 21a and gate drive circuit 21b) are provided for one display portion 33.

[0110] exist Figure 6 In the display device 10 of the structure shown, the pixels 34 in the odd rows are electrically connected to the gate drive circuit 21a through the wiring 31a, and the pixels 34 in the even rows are electrically connected to the gate drive circuit 21b through the wiring 31b. Like the wiring 31, the wiring 31a and the wiring 31b have the function of scanning lines.

[0111] The gate drive circuit 21a has a function of generating a signal for controlling the operation of the pixels 34 in the odd-numbered rows and supplying the signal to the pixels 34 through the wiring 31a. The gate drive circuit 21b has a function of generating a signal for controlling the operation of the pixels 34 in the even-numbered rows and supplying the signal to the pixels 34 through the wiring 31b.

[0112] Similar to the gate drive circuit 21, the gate drive circuit 21a and the gate drive circuit 21b have an area overlapping with the display unit 33. For example, similar to the gate drive circuit 21, the gate drive circuit 21a and the gate drive circuit 21b have an area overlapping with the pixel 34. In addition, the gate drive circuit 21a and the source drive circuit 22 are not clearly separated and have an area 23a where they overlap with each other. In addition, the gate drive circuit 21b and the source drive circuit 22 are not clearly separated and have an area 23b where they overlap with each other.

[0113] exist Figure 6 In the display device 10 of the structure shown, after writing image signals to all pixels 34 in the odd-numbered rows by operating the gate drive circuit 21a, image signals can be written to all pixels 34 in the even-numbered rows by operating the gate drive circuit 21b. That is, Figure 6The display device 10 of the structure shown can operate in an interlaced scanning mode. By operating the display device 10 in an interlaced scanning mode, high-speed operation can be achieved and the frame rate can be increased. In addition, compared with the case where the display device 10 is operated in a progressive scanning mode, the number of pixels 34 to which image signals are written during one frame can be reduced to half. Therefore, when the display device 10 is operated in an interlaced scanning mode, the clock frequency can be reduced compared with the case where the display device 10 is operated in a progressive scanning mode, thereby reducing the power consumption of the display device 10.

[0114] Although Figure 1 Although the structural example in which only one end of the wiring 32 is connected to the source driver circuit 22 is shown, a plurality of portions of the wiring 32 may be connected to the source driver circuit 22 . Figure 7 The structure example of the display device 10 in which the source driver circuit 22 is connected to both ends of the wiring 32 is shown. By connecting multiple parts of the wiring 32 to the source driver circuit 22, signal delays caused by wiring resistance, parasitic capacitance, etc. can be suppressed. As a result, high-speed operation of the display device 10 can be achieved.

[0115] In addition, one end and other parts of the wiring 32 other than the other end may be connected to the source driver circuit 22. For example, the center of the wiring 32 may be connected to the source driver circuit 22. By increasing the connection between the wiring 32 and the source driver circuit 22, signal delays and the like may be further suppressed, and high-speed operation of the display device 10 may be further achieved. In addition, for example, one end of the wiring 32 and the center of the wiring 32 may be connected to the source driver circuit 22, while the other end of the wiring 32 may not be connected to the source driver circuit 22.

[0116] In addition, in the case where one source driver circuit 22 is connected to a plurality of portions of the wiring 32, as shown in FIG. Figure 7 As shown in FIG. 1 , the area occupied by the source driver circuit 22 becomes larger. In this case as well, since the source driver circuit 22 is stacked in a manner having an area overlapping with the display unit 33, it is possible to suppress the display device 10 from being enlarged. Figure 7 The entire gate driving circuit 21 and the source driving circuit 22 are not clearly separated and overlap with each other, but in the case where a source driving circuit 22 is connected to multiple parts of the wiring 32, only a part of the gate driving circuit 21 may overlap with the source driving circuit 22.

[0117] In addition, multiple portions of the wiring 31 may be connected to one gate drive circuit 21. In this way, signal delays and the like can be suppressed, and high-speed operation of the display device 10 can be achieved. Figure 7The source driver circuit 22 shown in the figure occupies a larger area, but the gate driver circuit 21 is stacked so as to have a region overlapping with the display unit 33 , thereby suppressing an increase in size of the display device 10 .

[0118] Figures 1 to 7 The structures of the display device 10 shown in the figure can be combined appropriately. For example, Figure 2 The structure shown and Figure 6 In this case, in the display device 10, for example, a plurality of display units 33 may be provided, and the gate driving circuits 21 may be provided in twice the number of the display units 33, and the source driving circuits 22 may be provided in the same number as the display units 33.

[0119] <Configuration Example of Circuit 40 and Source Driver Circuit 22>

[0120] Figure 8 40 and the source driver circuit 22. Figure 8 Only one source driver circuit 22 is shown in the figure, but the circuit 40 can also be electrically connected to multiple source driver circuits 22.

[0121] The circuit 40 includes a receiving circuit 41, a serial-parallel conversion circuit 42, and a potential generating circuit 46a. The source driving circuit 22 includes a buffer circuit 43, a shift register circuit 44, a latch circuit 45, a transmission transistor logic circuit 46b, and an amplifier circuit 47. Here, the potential generating circuit 46a and the transmission transistor logic circuit 46b constitute a digital analog conversion circuit (DA conversion circuit) 46.

[0122] The receiving circuit 41 is electrically connected to the serial-parallel conversion circuit 42, the serial-parallel conversion circuit 42 is electrically connected to the buffer circuit 43, and the buffer circuit 43 is electrically connected to the shift register circuit 44 and the latch circuit 45. The shift register circuit 44 is electrically connected to the latch circuit 45, and the latch circuit 45 and the potential generating circuit 46a are electrically connected to the transmission transistor logic circuit 46b. The transmission transistor logic circuit 46b is electrically connected to the input terminal of the amplifier circuit 47, and the output terminal of the amplifier circuit 47 is electrically connected to the wiring 32.

[0123] The receiving circuit 41 has a function of receiving image data as a basis for the image signal generated by the source driving circuit 22. The image data may be single-ended image data. When receiving image data using a data transmission signal such as LVDS (Low Voltage Differential Signaling), the receiving circuit 41 may also have a function of converting the signal into a signal specification that can be processed internally.

[0124] The serial-to-parallel conversion circuit 42 has a function of converting the single-ended image data output by the receiving circuit 41 into parallel. By providing the serial-to-parallel conversion circuit 42 in the circuit 40, the image data etc. can be transmitted from the circuit 40 to the source driving circuit 22 etc. even if the load when transmitting the image data etc. from the circuit 40 to the source driving circuit 22 etc. is large.

[0125] The buffer circuit 43 may be, for example, a unit gain buffer. The buffer circuit 43 has a function of outputting data identical to the image data output from the serial-parallel conversion circuit 42. By providing the buffer circuit 43 in the source driver circuit 22, even if the potential corresponding to the image data output from the serial-parallel conversion circuit 42 decreases due to wiring resistance or the like when the potential is transmitted from the circuit 40 to the source driver circuit 22, the decrease can be compensated. Thus, even if the load when transmitting the image data or the like from the circuit 40 to the source driver circuit 22 or the like is large, the decrease in the driving capability of the source driver circuit 22 or the like can be suppressed.

[0126] The shift register circuit 44 has a function of generating a signal for controlling the operation of the latch circuit 45. The latch circuit 45 has a function of storing or outputting the image data output from the buffer circuit 43. In the latch circuit 45, either the storage or the output of the image data is selected according to the signal supplied from the shift register circuit 44.

[0127] The DA conversion circuit 46 has a function of converting the digital image data output by the latch circuit 45 into an analog image signal. The potential generating circuit 46a has a function of generating a type of potential corresponding to the number of bits of the image data that can be DA-converted and supplying the potential to the transfer transistor logic circuit 46b. For example, when the DA conversion circuit 46 has a function of converting 8-bit image data into an analog image signal, the potential generating circuit 46a can generate 256 types of potentials with different levels.

[0128] The transfer transistor logic circuit 46b has a function of receiving the image data from the latch circuit 45 and outputting any potential generated by the potential generating circuit 46a according to the digital value of the image data. For example, the larger the digital value of the image data, the higher the potential output by the transfer transistor logic circuit 46b. The potential output by the transfer transistor logic circuit 46b may be an image signal.

[0129] like Figure 8As shown, in the display device 10, the circuits constituting the DA conversion circuit 46 can be respectively provided in the source driver circuit 22 and the circuit 40. Specifically, circuits such as the transfer transistor logic circuit 46b, which are preferably provided in each source driver circuit, can be provided in the source driver circuit 22, and circuits such as the potential generation circuit 46a, which do not necessarily need to be provided in each source driver circuit, can be provided in the circuit 40. Thus, for example, compared with the case where all the circuits constituting the DA conversion circuit 46 are provided in the source driver circuit 22, the occupied area of the source driver circuit 22 can be reduced, and thus the number of source driver circuits 22 provided in the layer 20 can be increased. As a result, the number of display units 33 provided in the layer 30 can be increased, and high-speed operation, reduction in power consumption, improvement in clarity, and improvement in the resolution of the image that can be displayed of the display device 10 can be achieved. Here, the constituent elements of circuits other than the DA conversion circuit 46 can also be respectively provided in the source driver circuit 22 and the circuit 40.

[0130] In addition, as Figure 8 shown, in the case where the circuits constituting the DA conversion circuit 46 are respectively provided in the source driver circuit 22 and the circuit 40, the display device 10 can have, for example, one potential generation circuit 46a and the same number of transfer transistor logic circuits 46b as the source driver circuit 22.

[0131] The amplifier circuit 47 has a function of amplifying the image signal output from the transfer transistor logic circuit 46b and outputting the image signal to the wiring 32 serving as a data line. By providing the amplifier circuit 47, the image signal can be stably supplied to the pixel 34. As the amplifier circuit 47, a voltage follower circuit having an operational amplifier or the like can be appropriately used. In addition, in the case where a circuit having a differential input circuit is used as the amplifier circuit, the offset voltage of the differential input circuit is preferably as close to 0V as possible.

[0132] In addition, the circuit 40 can include various circuits in addition to the reception circuit 41, the serial-parallel conversion circuit 42, and the potential generation circuit 46a. For example, the circuit 40 can include a control circuit having functions of generating a start pulse signal, a clock signal, and the like.

[0133] <Structural Example of DA Conversion Circuit 46>

[0134] Fig. 9 is a circuit diagram showing a structural example of the potential generation circuit 46a and the transfer transistor logic circuit 46b constituting the DA conversion circuit 46. The DA conversion circuit 46 having the Fig. 9 shown structure can convert 8-bit image data D<1> to image data D<8> into an analog image signal IS.

[0135] In this specification and the like, for example, image data D <1> The image data D represents the first bit. <2> represents the second image data D, and the image data D <8> Indicates the image data D of the eighth bit.

[0136] Fig. 9 The potential generating circuit 46a of the structure shown includes resistors 48[1] to 48

[256] , which are connected in series. That is, the DA conversion circuit 46 may be a resistor series type DA conversion circuit.

[0137] One terminal of resistor 48[1] can be supplied with potential VDD. One terminal of resistor 48

[256] can be supplied with potential VSS. Thus, potentials V at different levels can be output from each terminal of resistors 48[1] to 48

[256] . 1 To V 256 In addition, although Fig. 9 The potential V 1 The potential generating circuit 46a is an example of a structure when the potential is VDD, but the potential V 256 The structure is a potential VSS. In addition, the resistor 48

[256] may not be provided and the potential V 1 is the potential VDD and the potential V 256 The structure has a potential of VSS.

[0138] In this specification, for example, the potential VDD may be a high potential, and the potential VSS may be a low potential. Here, the low potential may be, for example, a ground potential. In addition, the high potential is a potential higher than the low potential, and when the low potential is a ground potential, the high potential may be a positive potential.

[0139] Fig. 9 The transfer transistor logic circuit 46b of the structure shown is composed of eight stages of transfer transistors 49. Specifically, the circuit of each stage is branched into two paths, and the transfer transistor logic circuit 46b has a total of 256 paths. That is, the transfer transistors 49 are electrically connected in a knockout diagram. The analog image signal IS can be output from one of the source and drain of the eighth stage transfer transistor 49 as the last stage.

[0140] For example, the image data D <1> Supplied to the first stage transfer transistor 49, the image data D <2> Supplied to the second stage transfer transistor 49, and the image data D <8> Supplied to the eighth-stage transfer transistor 49. With the above structure, the potential of the image signal IS can be the potential V according to the image data D. 1 To V 256 Therefore, the digital image data can be converted into an analog image signal IS.

[0141] also, Fig. 9 The transfer transistor logic circuit 46b shown in the figure includes both the n-channel transfer transistor 49 and the p-channel transfer transistor 49, but only the n-channel transfer transistor 49 may be provided. <1> To image data D <8> In addition, its complementary data can also be supplied to the gate of the transfer transistor 49 to set all the transfer transistors 49 provided in the transfer transistor logic circuit 46b to n-channel transistors.

[0142] Fig. 9 The structure shown can also be applied to the DA conversion circuit 46 having the function of DA conversion of image data D having a bit number other than 8 bits. For example, by providing 1024 or 1023 resistors 48 in the potential generation circuit 46a and providing 10 stages of transfer transistors 49 in the transfer transistor logic circuit 46b, the DA conversion circuit 46 can have the function of DA conversion of image data D having 10 bits.

[0143] <Configuration Example of Gate Drive Circuit 21>

[0144] Fig.10 2 is a block diagram showing a configuration example of the gate drive circuit 21. The gate drive circuit 21 includes a shift register circuit SR composed of a plurality of set-reset flip-flops. The shift register circuit SR is electrically connected to the wiring 31 used as a scan line and has a function of outputting a signal to the wiring 31.

[0145] The signal RES is a reset signal. For example, by setting the signal RES to a high potential, all outputs of the shift register circuit SR can be set to a low potential. The signal SP is a start pulse signal. By inputting this signal to the gate drive circuit 21, the shift operation of the shift register circuit SR can be started. The signal PWC is a pulse width control signal and has a function of controlling the pulse width of the signal output by the shift register circuit SR to the wiring 31. The signals CLK[1], CLK[2], CLK[3], and CLK[4] are clock signals, and, for example, two of the signals CLK[1] to CLK[4] can be input to one shift register circuit SR.

[0146] In addition, Fig.10 In the illustrated structure, by setting the wiring 31 electrically connected to the shift register circuit SR to other wirings, etc., it is possible to apply to the shift register circuit 44 included in the source driver circuit 22.

[0147] Fig.11A is a diagram showing a signal input to the shift register circuit SR and a signal output from the shift register circuit SR. Fig.11AThe case where a signal CLK[1] and a signal CLK[3] are input as clock signals is shown.

[0148] The signal FO is an output signal, for example, a signal output to the wiring 31. The signal SROUT is a shift signal, which may be a signal LIN input to the next stage shift register circuit SR. Fig.11A Among the signals shown, the signal RES, the signal PWC, the signal CLK[1], the signal CLK[3], and the signal LIN are signals input to the shift register circuit SR, and the signal FO and the signal SROUT are signals output from the shift register circuit SR.

[0149] Fig. 11B The input and output signals are shown as Fig.11A 1 is a circuit diagram of a structural example of a shift register circuit SR for shifting signals of FIG. Shift register circuit SR includes transistors 51 to 63 and capacitors 64 to 66.

[0150] One of the source and the drain of the transistor 51 is electrically connected to one of the source and the drain of the transistor 52, one of the source and the drain of the transistor 56, and one of the source and the drain of the transistor 59. The gate of the transistor 52 is electrically connected to one of the source and the drain of the transistor 53, one of the source and the drain of the transistor 54, one of the source and the drain of the transistor 55, the gate of the transistor 58, the gate of the transistor 61, and one of the electrodes of the capacitor 64. The other of the source and the drain of the transistor 56 is electrically connected to the gate of the transistor 57 and one of the electrodes of the capacitor 65. The other of the source and the drain of the transistor 59 is electrically connected to the gate of the transistor 60 and one of the electrodes of the capacitor 66. One of the source and the drain of the transistor 60 is electrically connected to one of the source and the drain of the transistor 61, the gate of the transistor 62, and the other of the electrodes of the capacitor 66.

[0151] The gates of transistor 51 and transistor 55 receive the signal LIN. The gate of transistor 53 receives the signal CLK[3]. The gate of transistor 54 receives the signal RES. The source and drain of transistor 57 receive the signal CLK[1]. The other of the source and drain of transistor 60 receives the signal PWC.

[0152] One of the source and drain of the transistor 62 and one of the source and drain of the transistor 63 are electrically connected to one wiring 31, and as described above, the signal FO is output from the wiring 31. The signal SROUT is output from the other of the source and drain of the transistor 57, one of the source and drain of the transistor 58, and the other electrode of the capacitor 65.

[0153] The potential VDD is supplied to the other of the source and drain of the transistor 51, the other of the source and drain of the transistor 53, the other of the source and drain of the transistor 54, the gate of the transistor 56, the gate of the transistor 59, and the other of the source and drain of the transistor 62. The potential VSS is supplied to the other of the source and drain of the transistor 52, the other of the source and drain of the transistor 55, the other of the source and drain of the transistor 58, the other of the source and drain of the transistor 61, the other of the source and drain of the transistor 63, and the other electrode of the capacitor 64.

[0154] The transistor 63 is a bias transistor and has a function of a constant current source. A potential Vbias serving as a bias potential can be supplied to the gate of the transistor 63.

[0155] The source follower circuit 67 is composed of the transistor 62 and the transistor 63. By providing the source follower circuit 67 in the shift register circuit SR, even if the attenuation of the signal due to wiring resistance, parasitic capacitance, etc. occurs inside the shift register circuit SR, the potential drop of the signal FO due to the attenuation can be suppressed. As a result, the operation of the display device 10 can be accelerated. In addition, the source follower circuit 67 can be a circuit other than a source follower circuit as long as it has a function as a buffer.

[0156] <Structural Example of Region 23>

[0157] Fig.12 2 is a diagram showing a structural example of a region 23 which is a region where the gate driver circuit 21 and the source driver circuit 22 overlap. Fig.12 As shown, in the region 23, a region including elements constituting the gate drive circuit 21 and a region including elements constituting the source drive circuit 22 are regularly arranged. Fig.12 In the embodiment, transistor 71 is used as an element constituting the gate driving circuit 21, and transistor 72 is used as an element constituting the source driving circuit 22.

[0158] Fig.12 The case where the region including the elements constituting the gate driver circuit 21 is arranged in the first and third rows and the region including the elements constituting the source driver circuit 22 is arranged in the second and fourth rows is shown. In the region 23, dummy elements are arranged between the regions including the elements constituting the gate driver circuit 21. In addition, dummy elements are arranged between the regions including the elements constituting the source driver circuit 22. Fig.12 An example of the structure of the region 23 is shown in which dummy transistors 73 as dummy elements are provided on the sides of the transistors 71 and 72 .

[0159] By providing a dummy element such as a dummy transistor 73 in the region 23 and allowing the dummy element to absorb impurities, it is possible to suppress the diffusion of impurities into the transistors 71 and 72. Thus, the reliability of the transistors 71 and 72 can be improved, thereby improving the reliability of the display device 10. Fig.12 In the embodiment, the transistor 71, the transistor 72, and the dummy transistor 73 are arranged in a matrix shape, but they do not have to be arranged in a matrix shape.

[0160] Fig.13 FIG. 2 is a top view showing a structural example of region 70 as a part of region 23. Fig.12 and Fig.13 As shown, region 70 includes a transistor 71, a transistor 72, and two dummy transistors 73. Fig.13 As shown, the transistor 71 includes a channel formation region 110, a source region 111, and a drain region 112. In addition, a gate electrode 113 having a region overlapping with the channel formation region 110 is also included.

[0161] exist Fig.13 The components such as the gate insulator are omitted. Fig.13 The channel formation region, the source region, and the drain region are not clearly shown separately.

[0162] An opening 114 is provided in the source region 111, and the source region 111 is electrically connected to a wiring 115 through the opening 114. An opening 116 is provided in the drain region 112, and the drain region 112 is electrically connected to a wiring 117 through the opening 116.

[0163] An opening 118 is provided in the gate electrode 113, and the gate electrode 113 is electrically connected to the wiring 121 through the opening 118. An opening 119 is provided in the wiring 115, and the wiring 115 is electrically connected to the wiring 122 through the opening 119. An opening 120 is provided in the wiring 117, and the wiring 117 is electrically connected to the wiring 123 through the opening 120. That is, the source region 111 is electrically connected to the wiring 122 through the wiring 115, and the drain region 112 is electrically connected to the wiring 123 through the wiring 117.

[0164] The transistor 72 includes a channel formation region 130, a source region 131, and a drain region 132. In addition, a gate electrode 133 having a region overlapping with the channel formation region 130 is included.

[0165] An opening 134 is provided in the source region 131 , and the source region 131 is electrically connected to the wiring 135 through the opening 134 . An opening 136 is provided in the drain region 132 , and the drain region 132 is electrically connected to the wiring 137 through the opening 136 .

[0166] An opening 138 is provided in the gate electrode 133, and the gate electrode 133 is electrically connected to the wiring 141 through the opening 138. An opening 139 is provided in the wiring 135, and the wiring 135 is electrically connected to the wiring 142 through the opening 139. An opening 140 is provided in the wiring 137, and the wiring 137 is electrically connected to the wiring 143 through the opening 140. That is, the source region 131 is electrically connected to the wiring 142 through the wiring 135, and the drain region 132 is electrically connected to the wiring 143 through the wiring 137.

[0167] In addition, the channel formation region 110 and the channel formation region 130 may be arranged in the same layer. In addition, the source region 111 and the drain region 112 and the source region 131 and the drain region 132 may be arranged in the same layer. In addition, the gate electrode 113 and the gate electrode 133 may be arranged in the same layer. In addition, the wiring 115 and the wiring 117 and the wiring 135 and the wiring 137 may be arranged in the same layer. In other words, the transistor 71 and the transistor 72 may be arranged in the same layer. Thus, compared with the case where the transistor 71 and the transistor 72 are respectively arranged in layers different from each other, the manufacturing process of the display device 10 can be simplified, so that an inexpensive display device 10 can be provided.

[0168] Wiring 121 to wiring 123 electrically connected to transistor 71 constituting gate drive circuit 21 are arranged in the same layer. In addition, wiring 141 to wiring 143 electrically connected to transistor 72 constituting source drive circuit 22 are arranged in the same layer. Furthermore, wiring 121 to wiring 123 are arranged in a layer different from wiring 141 to wiring 143. With the aid of the above structure, electrical short circuit of transistor 71 as an element constituting gate drive circuit 21 and transistor 72 as an element constituting source drive circuit 22 can be suppressed. Thus, even if gate drive circuit 21 and source drive circuit 22 are not clearly separated and have overlapping areas, malfunction of gate drive circuit 21 and source drive circuit 22 can be suppressed. Thus, the reliability of display device 10 can be improved.

[0169] In this specification and the like, “the same layer as A” refers to, for example, a layer formed in the same process as A and containing the same material.

[0170] Although in Fig.13 2 shows a structure in which the wirings 141 to 143 are provided above the wirings 121 to 123 , but the wirings 141 to 143 may be provided below the wirings 121 to 123 .

[0171] In addition, although Fig.13, the wiring 121 to the wiring 123 extends in the horizontal direction and the wiring 141 to the wiring 143 extends in the vertical direction, but one embodiment of the present invention is not limited to this. For example, a structure in which the wiring 121 to the wiring 123 extends in the vertical direction and the wiring 141 to the wiring 143 extends in the horizontal direction may be adopted. Alternatively, the wiring 121 to the wiring 123 and the wiring 141 to the wiring 143 may both extend in the horizontal direction or the vertical direction.

[0172] The pseudo transistor 73 includes a semiconductor 151 and a conductor 152. The conductor 152 has a region overlapping with the semiconductor 151. The semiconductor 151 can be formed in the same layer as the channel formation region of the transistor 71 and the transistor 72. In addition, the conductor 152 can be formed in the same layer as the gate electrode of the transistor 71 and the transistor 72. In addition, the pseudo transistor 73 may not have one of the semiconductor 151 and the conductor 152.

[0173] The semiconductor 151 and the conductor 152 may not be electrically connected to other wirings, etc. A constant potential may be supplied to the semiconductor 151 and / or the conductor 152. For example, a ground potential may be supplied to the semiconductor 151 and / or the conductor 152.

[0174] <Structural Example of Pixel 34>

[0175] FIG. 14A to FIG. 14E 3 is a diagram for explaining the colors presented by the pixels 34 provided in the display device 10. Fig.14A As shown in FIG. 1 , a pixel 34 emitting red (R), a pixel 34 emitting green (G), and a pixel 34 emitting blue (B) may be provided in a display device according to one embodiment of the present invention. Fig. 14B As shown, a pixel 34 emitting cyan (C), a pixel 34 emitting magenta (M), and a pixel 34 emitting yellow (Y) may be provided in the display device 10 .

[0176] Or, if Fig. 14C As shown, a pixel 34 emitting red (R), a pixel 34 emitting green (G), a pixel 34 emitting blue (B), and a pixel 34 emitting white (W) may be provided in the display device 10. Alternatively, as Fig.14D As shown, a pixel 34 emitting red (R), a pixel 34 emitting green (G), a pixel 34 emitting blue (B), and a pixel 34 emitting yellow (Y) may be provided in the display device 10. Alternatively, as Fig.14E As shown, a pixel 34 emitting cyan (C), a pixel 34 emitting magenta (M), a pixel 34 emitting yellow (Y), and a pixel 34 emitting white (W) may be provided in the display device 10 .

[0177] like Fig. 14C and Fig.14EAs shown in FIG. 1 , by providing the pixel 34 emitting white light in the display device 10, the brightness of the displayed image can be increased. Fig.14D As shown in FIG. 1 , by increasing the number of colors emitted by the pixel 34, the reproducibility of intermediate colors can be improved, thereby improving the display quality.

[0178] Fig.15A and Fig. 15B is a circuit diagram showing a structural example of the pixel 34. Fig.15A The pixel 34 of the structure shown includes a liquid crystal element 570, a transistor 550, and a capacitor 560. In addition, in addition to the wiring 31 and the wiring 32, the pixel 34 is also electrically connected to the wiring 35 and the like.

[0179] The potential of one electrode in the liquid crystal element 570 is appropriately set according to the specification of the pixel 34. The alignment state of the liquid crystal element 570 is set according to the image signal written to the pixel 34. In addition, a common potential may be supplied to one electrode in the liquid crystal element 570 of each of the plurality of pixels 34. In addition, a different potential may be supplied to one electrode in the liquid crystal element 570 of each of the pixels 34 of each row.

[0180] In addition, Fig. 15B The pixel 34 of the structure shown includes a transistor 552, a transistor 554, a capacitor 562, and a light-emitting element 572. As the light-emitting element 572, an EL element using electroluminescence can be used. The EL element has a layer containing a light-emitting compound between a pair of electrodes (hereinafter referred to as an EL layer). When a potential difference higher than the threshold voltage of the EL element is generated between the pair of electrodes, holes are injected into the EL layer from the anode side, and electrons are injected into the EL layer from the cathode side. The injected electrons and holes recombine in the EL layer, whereby the light-emitting substance contained in the EL layer emits light.

[0181] EL elements are distinguished depending on whether the light-emitting material is an organic compound or an inorganic compound. Generally, the former is called an organic EL element, and the latter is called an inorganic EL element.

[0182] In an organic EL element, electrons are injected into the EL layer from one electrode and holes are injected into the EL layer from the other electrode by applying voltage. The light-emitting organic compound forms an excited state by the recombination of these carriers (electrons and holes), and emits light when returning from the excited state to the ground state. Due to this mechanism, this light-emitting element is called a current-excitation light-emitting element.

[0183] The EL layer may include, in addition to the light-emitting compound, a substance with high hole injection property, a substance with high hole transport property, a hole blocking material, a substance with high electron transport property, a substance with high electron injection property, or a bipolar substance (a substance with high electron transport property and hole transport property).

[0184] The EL layer can be formed by a method such as an evaporation method (including a vacuum evaporation method), a transfer method, a printing method, an inkjet method, or a coating method.

[0185] Inorganic EL elements are classified into dispersed-type inorganic EL elements and thin-film-type inorganic EL elements according to their element structures. Dispersed-type inorganic EL elements include a light-emitting layer in which particles of a light-emitting material are dispersed in a binder, and its light-emitting mechanism is donor-acceptor recombination-type light-emitting using donor energy levels and acceptor energy levels. Thin-film-type inorganic EL elements are structures in which a light-emitting layer is sandwiched between dielectric layers, and the dielectric layers sandwiching the light-emitting layer are sandwiched between electrodes, and its light-emitting mechanism is localized light-emitting using inner shell electron transitions of metal ions.

[0186] In order to extract the light, at least one of the pair of electrodes of the light-emitting element can be made transparent. A transistor and a light-emitting element are formed on a substrate, and the light-emitting element can adopt a top emission structure that extracts light from the surface on the opposite side of the substrate, a bottom emission structure that extracts light from the surface on one side of the substrate, and a double-sided emission structure that extracts light from both surfaces.

[0187] As light-emitting elements other than the light-emitting element 572 , the same elements as the light-emitting element 572 can be used.

[0188] One of the source and the drain of the transistor 552 is electrically connected to the wiring 32. The other of the source and the drain of the transistor 552 is electrically connected to one electrode of the capacitor 562 and the gate of the transistor 554. The other electrode of the capacitor 562 is electrically connected to the wiring 35a. The gate of the transistor 552 is electrically connected to the wiring 31. One of the source and the drain of the transistor 554 is electrically connected to the wiring 35a. The other of the source and the drain of the transistor 554 is electrically connected to one electrode of the light emitting element 572. The other electrode of the light emitting element 572 is electrically connected to the wiring 35b. The wiring 35a is supplied with the potential VSS, and the wiring 35b is supplied with the potential VDD.

[0189] exist Fig. 15B In the pixel 34 having the structure shown, the current flowing through the light-emitting element 572 is controlled according to the potential supplied to the gate of the transistor 554, so that the brightness of light emitted from the light-emitting element 572 is controlled.

[0190] Fig. 15C Shown with Fig. 15B The structure of the pixel 34 shown in the figure is different from that of the pixel 34. Fig. 15C In the pixel 34 of the structure shown, one of the source and the drain of the transistor 552 is electrically connected to the wiring 32. The other of the source and the drain of the transistor 552 is electrically connected to one electrode of the capacitor 562 and the gate of the transistor 554. The gate of the transistor 552 is electrically connected to the wiring 31. One of the source and the drain of the transistor 554 is electrically connected to the wiring 35a. The other of the source and the drain of the transistor 554 is electrically connected to the other electrode of the capacitor 562 and one electrode of the light-emitting element 572. The other electrode of the light-emitting element 572 is electrically connected to the wiring 35b. The wiring 35a is supplied with a potential VDD, and the wiring 35b is supplied with a potential VSS.

[0191] Fig.16A An example of the structure of the pixel 34 is shown. FIG. 15A to FIG. 15C The pixel 34 of the illustrated structure differs in that it includes a memory. Fig.16A The pixel 34 of the structure shown includes a transistor 511, a transistor 513, a capacitor 515, and a circuit 401. The pixel 34 is electrically connected to wirings 31_1 and 31_2 as the wirings 31 used as scan lines, and to wirings 32_1 and 32_2 as the wirings 32 used as data lines.

[0192] One of the source and the drain of the transistor 511 is electrically connected to the wiring 32_1. The other of the source and the drain of the transistor 511 is electrically connected to one electrode of the capacitor 515. The gate of the transistor 511 is electrically connected to the wiring 31_1. One of the source and the drain of the transistor 513 is electrically connected to the wiring 32_2. The other of the source and the drain of the transistor 513 is electrically connected to the other electrode of the capacitor 515 and the circuit 401. The gate of the transistor 513 is electrically connected to the wiring 31_2.

[0193] The circuit 401 includes at least one display element. Various elements can be used as the display element, and typical examples include light-emitting elements such as organic light-emitting elements and LED elements, liquid crystal elements, and MEMS (Micro Electro Mechanical Systems) elements.

[0194] In this specification and the like, a voltage supplied to a display element such as a light-emitting element or a liquid crystal element refers to a difference between a potential applied to one electrode in the display element and a potential applied to the other electrode in the display element.

[0195] A node connecting the transistor 511 and the capacitor 515 is denoted as N1, and a node connecting the transistor 513 and the circuit 401 is denoted as N2.

[0196] The pixel 34 can maintain the potential of the node N1 by turning off the transistor 511. In addition, the potential of the node N2 can be maintained by turning off the transistor 513. In addition, by writing a predetermined potential to the node N1 through the transistor 511 when the transistor 513 is in the off state, the potential of the node N2 can be changed in accordance with the potential change of the node N1 due to the capacitive coupling through the capacitor 515.

[0197] Here, as the transistor 511 and the transistor 513, a transistor containing a metal oxide in the channel formation region (hereinafter also referred to as an OS transistor) can be used. The band gap of the metal oxide can be greater than 2 eV or greater than 2.5 eV. Therefore, the leakage current (off-state current) of the OS transistor in the non-conducting state is extremely small. Therefore, by using OS transistors as the transistor 511 and the transistor 513, the potentials of the node N1 and the node N2 can be maintained for a long time.

[0198] As the metal oxide, it is preferred to use a metal oxide such as In-M-Zn oxide (the element M is one or more selected from aluminum, gallium, yttrium, tin, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten and magnesium). In particular, aluminum, gallium, yttrium or tin can be used as the element M. In addition, as the metal oxide, indium oxide, zinc oxide, In-Ga oxide, In-Zn oxide, Ga-Zn oxide or gallium oxide can also be used.

[0199] [An example of the operation method of pixel 34]

[0200] Next, refer to Fig. 16B right Fig.16A An example of the operation method of the pixel 34 having the structure shown will be described. Fig. 16B is based on Fig.16A The timing chart of the operation of the pixel 34 having the structure shown is shown. Note that for the sake of convenience, the influence of various resistances such as wiring resistance, parasitic capacitance of transistors and wiring, and threshold voltage of transistors are not considered here.

[0201] exist Fig. 16B In the operation shown, one frame period is divided into a period T1 and a period T2. The period T1 is a period for writing a potential to the node N2, and the period T2 is a period for writing a potential to the node N1.

[0202] In the period T1, a potential that turns on the transistor is supplied to both the wiring 31_1 and the wiring 31_2. In addition, a fixed potential V is supplied to the wiring 32_1. ref , supplying a potential V to the wiring 32_2 w .

[0203] The node N1 is supplied with a potential V from the wiring 32_1 via the transistor 511. ref In addition, the node N2 is supplied with a potential V from the wiring 32_2 via the transistor 513. w Therefore, capacitor 515 maintains the potential difference V w -V ref status.

[0204] Next, in period T2, a potential for turning on the transistor 511 is supplied to the wiring 31_1, and a potential for turning off the transistor 513 is supplied to the wiring 31_2. data , a predetermined constant potential is supplied to the wiring 32_2. Alternatively, the potential of the wiring 32_2 may be a floating potential.

[0205] The node N1 is supplied with a potential V via the transistor 511. data At this time, due to the capacitive coupling through capacitor 515, the corresponding potential V data The potential of the node N2 changes by a potential dV. That is, the circuit 401 receives the potential V w The potential added to the potential dV. Note that although Fig. 16B The potential dV is shown as a positive value, but it can also be a negative value. data It can also be compared with the potential V ref Low.

[0206] Here, the potential dV is basically determined by the capacitance value of the capacitor 515 and the capacitance value of the circuit 401. When the capacitance value of the capacitor 515 is sufficiently larger than the capacitance value of the circuit 401, the potential dV becomes close to the potential difference V data -V ref The potential.

[0207] As described above, since the pixel 34 can combine the two data signals to generate a potential supplied to the circuit 401 including the display element, the image displayed on the display unit 33 can be corrected in the pixel 34. Here, one of the two data signals can be the above-mentioned image signal, and the other of the two data signals can be, for example, a correction signal. For example, by increasing the potential V corresponding to the correction signal during the period T1 w After being supplied to the node N2, the potential V corresponding to the image signal is increased during the period T2. data The image signal supplied to the node N1 and displayed on the display unit 33 is an image whose image signal has been corrected by the correction signal. The source driver circuit 22 included in the display device 10 can generate not only the image signal but also the correction signal and the like.

[0208] In addition, the pixel 34 can generate a potential exceeding the maximum potential that can be supplied to the wiring 32_1 and the wiring 32_2. For example, when a light-emitting element is used, high dynamic range (HDR) display can be performed. In addition, when a liquid crystal element is used, overdrive can be performed.

[0209] [Configuration Example of Circuit 401]

[0210] Fig. 16C and Fig.16D An example of the structure of the pixel 34 including a specific example of the structure of the circuit 401 is shown. Fig. 16C The circuit 401 in the pixel 34 of the illustrated structure includes a liquid crystal element 519 and a capacitor 517 .

[0211] One electrode of the liquid crystal element 519 is electrically connected to the node N2. The other electrode of the liquid crystal element 519 is electrically connected to the wiring 533. One electrode of the capacitor 517 is electrically connected to the node N2. The other electrode of the capacitor 517 is electrically connected to the wiring 531. The wiring 531 and the wiring 533 may be common wirings for all pixels 34 provided in the display device 10. In this case, the potential supplied to the wiring 531 and the wiring 533 is a common potential.

[0212] The capacitor 517 is used as a storage capacitor. The capacitor 517 may also be omitted.

[0213] Fig. 16C The pixel 34 of the structure shown can supply a potential higher than the potential that can be generated by the source driver circuit 22, etc. to one electrode in the liquid crystal element 519. Thus, even if the source driver circuit 22 is not made to have a high withstand voltage, a high voltage can be supplied to the liquid crystal element 519, and an inexpensive display device 10 can be provided. In addition, the increase in power consumption of the display device 10 is suppressed, and at the same time, for example, high-speed display can be achieved by overdriving or liquid crystal materials with high driving voltage can be used. In addition, by providing a correction signal to the wiring 32_1 or the wiring 32_2, the image signal can be corrected according to the use temperature or the degradation state of the liquid crystal element 519.

[0214] Set in Fig.16D The circuit 401 in the pixel 34 of the illustrated structure includes a light emitting element 523 , a transistor 521 , and a capacitor 517 .

[0215] One of the source and the drain of the transistor 521 is electrically connected to the wiring 537. The other of the source and the drain of the transistor 521 is electrically connected to one electrode of the light-emitting element 523. The gate of the transistor 521 is electrically connected to the node N2. One electrode of the capacitor 517 is electrically connected to the node N2. The other electrode of the capacitor 517 is electrically connected to the wiring 535. The other electrode of the light-emitting element 523 is electrically connected to the wiring 539.

[0216] The wiring 535 may be, for example, a common wiring for all pixels 34 provided in the display device 10. In this case, the potential supplied to the wiring 535 is a common potential. In addition, a constant potential may be supplied to the wiring 537 and the wiring 539. For example, the wiring 537 and the wiring 539 may be supplied with a high potential and a low potential, respectively.

[0217] The transistor 521 has a function of controlling a current supplied to the light emitting element 523. The capacitor 517 is used as a storage capacitor. The capacitor 517 may also be omitted.

[0218] also, Fig.16D Although the anode side of the light-emitting element 523 is electrically connected to the transistor 521, the cathode side of the light-emitting element 523 may be electrically connected to the transistor 521. In this case, the potential value of the wiring 537 and the potential value of the wiring 539 can be changed as appropriate.

[0219] Fig.16D The pixel 34 of the structure shown can supply a potential higher than the potential that can be generated by the source driver circuit 22 to one electrode in the light emitting element 523. Thus, even if the source driver circuit 22 is not made to have a high withstand voltage, a high voltage can be supplied to the gate of the transistor 521, and an inexpensive display device 10 can be provided. By supplying a high potential to the gate of the transistor 521, a large current can flow through the light emitting element 523, so in Fig.16D In the pixel 34 having the structure shown, for example, HDR display can be realized. In addition, by supplying a correction signal to the wiring 32_1 or the wiring 32_2, variations in the electrical characteristics of the transistor 521 and the light-emitting element 523 can be corrected.

[0220] In addition, by supplying a high potential to the gate of the transistor 521, a high voltage can be supplied to the light-emitting element 523. Specifically, for example, the potential of the wiring 537 can be set to a high potential. Thus, in the case where the light-emitting element 523 is an organic EL element, the light-emitting element can have a series structure described later. Thus, the current efficiency and external quantum efficiency of the light-emitting element 523 can be improved. Therefore, the display device 10 can display a high-brightness image. In addition, the power consumption of the display device 10 can be reduced.

[0221] In addition, not limited to Fig. 16C and Fig.16D The circuit shown in FIG. 1 may also adopt a structure with additional transistors or capacitors. Fig. 16C and Fig.16D In the structure shown in FIG. 1 , a transistor and a capacitor are added to set three nodes for holding potential. That is, in pixel 34, in addition to node N1 and node N2, a node for holding potential can be set. Thus, the potential of node N2 can be further increased. Therefore, in pixel 34 having Fig. 16C In the case of the structure shown in FIG. 5 , a higher voltage can be supplied to the liquid crystal element 519. Fig.16D In the case of the structure shown, a larger current can be supplied to the light emitting element 523.

[0222] 17A to 17D 4 is a diagram showing a configuration example of the circuit 401 when the light-emitting element 523 is used as a display element. Fig.16D The circuit 401 shown in the structure also has Fig.17A The circuit 401 of the structure shown includes a capacitor 517 , a transistor 521 , and a light emitting element 523 .

[0223] exist Fig.17A In the circuit 401 shown, the node N2 is electrically connected to the gate of the transistor 521 and one electrode of the capacitor 517. One of the source and the drain of the transistor 521 is electrically connected to the wiring 537. The other of the source and the drain of the transistor 521 is electrically connected to the other electrode of the capacitor 517. The other electrode of the capacitor 517 is electrically connected to one electrode of the light emitting element 523. The other electrode of the light emitting element 523 is electrically connected to the wiring 539.

[0224] and Fig.16D The circuit 401 shown in the structure is similar, Fig. 17B The circuit 401 of the structure shown includes a capacitor 517 , a transistor 521 , and a light emitting element 523 .

[0225] exist Fig. 17B In the circuit 401 shown, the node N2 is electrically connected to the gate of the transistor 521 and one electrode of the capacitor 517. One electrode of the light emitting element 523 is electrically connected to the wiring 537. The other electrode of the light emitting element 523 is electrically connected to one of the source and the drain of the transistor 521. The other of the source and the drain of the transistor 521 is electrically connected to the other electrode of the capacitor 517. The other electrode of the capacitor 517 is electrically connected to the wiring 539.

[0226] Fig. 17C Show Fig.17AThe circuit 401 shown is a configuration example of the circuit 401 in which a transistor 525 is added. One of the source and the drain of the transistor 525 is electrically connected to the other of the source and the drain of the transistor 521 and the other of the capacitor 517. The other of the source and the drain of the transistor 525 is electrically connected to one electrode of the light emitting element 523. The gate of the transistor 525 is electrically connected to the wiring 541. The wiring 541 is used as a scanning line for controlling the conduction of the transistor 525.

[0227] In having Fig. 17C In the pixel 34 of the circuit 401 having the structure shown, even if the potential of the node N2 becomes equal to or higher than the threshold voltage of the transistor 521, current can flow through the light emitting element 523 only by turning on the transistor 525. This can prevent the display device 10 from malfunctioning.

[0228] Fig.17D Show Fig. 17C The circuit 401 shown is a configuration example of the circuit 401 in which a transistor 527 is added. One of the source and the drain of the transistor 527 is electrically connected to the other of the source and the drain of the transistor 521. The other of the source and the drain of the transistor 527 is electrically connected to a wiring 543. The gate of the transistor 527 is electrically connected to a wiring 545. The wiring 545 is used as a scanning line for controlling conduction of the transistor 527.

[0229] The wiring 543 can be electrically connected to a supply source of a specific potential such as a reference potential. By supplying the specific potential from the wiring 543 to the other of the source and the drain of the transistor 521 , writing of the image signal to the pixel 34 can be stabilized.

[0230] In addition, the wiring 543 can be electrically connected to the circuit 520. The circuit 520 can have one or more of a function of a supply source of the above-mentioned specific potential, a function of obtaining the electrical characteristics of the transistor 521, and a function of generating a correction signal.

[0231] <Structural Example 2 of Display Device>

[0232] Fig.18 It is shown that the pixel 34 has Fig.16A , Fig. 16C and Fig.16D The structure shown is a block diagram of an example of the structure of the display device 10. Fig.18 The display device 10 shown in the structure includes Figure 1 The display device 10 shown in FIG. 1 also includes a demultiplexing circuit 24. Fig.18 As shown, the demultiplexing circuit may be provided in the layer 20, for example. In addition, the number of the demultiplexing circuits 24 may be the same as the number of columns of the pixels 34 provided on the display unit 33, for example.

[0233] The gate driving circuit 21 is electrically connected to the pixel 34 via the wiring 31_1. The gate driving circuit 21 is electrically connected to the pixel 34 via the wiring 31_2. The wiring 31_1 and the wiring 31_2 are used as scanning lines.

[0234] The source driver circuit 22 is electrically connected to the input terminal of the demultiplexing circuit 24. The first output terminal of the demultiplexing circuit 24 is electrically connected to the pixel 34 through the wiring 32_1. The second output terminal of the demultiplexing circuit 24 is electrically connected to the pixel 34 through the wiring 32_2. The wiring 32_1 and the wiring 32_2 are used as data lines.

[0235] In addition, the source driving circuit 22 and the demultiplexing circuit 24 may be collectively referred to as a source driving circuit. In other words, the demultiplexing circuit 24 may also be included in the source driving circuit 22.

[0236] exist Fig.18 In the display device 10 of the structure shown in FIG. 1 , the source driver circuit 22 has a function of generating an image signal S1 and an image signal S2. The demultiplexer circuit 24 has a function of supplying the image signal S1 to the pixel 34 through the wiring 32_1 and a function of supplying the image signal S2 to the pixel 34 through the wiring 32_2. Fig. 16B The method shown makes Fig.18 The display device 10 with the structure shown in the figure can operate by making the potential V data becomes a potential equivalent to the image signal S1, and V w This becomes a potential equivalent to the image signal S2.

[0237] like Fig. 16B As shown, by setting the potential V w After being supplied to the node N2, the potential V data Supplied to node N1, making the potential of node N2 become “V w +dV". Here, as described above, the potential dV corresponds to the potential V data Thus, the image signal S1 can be added to the image signal S2. That is, the image signal S2 can be overlapped with the image signal S1.

[0238] The potential V corresponding to the image signal S1 data and the potential V corresponding to the image signal S2 wThe size of is limited by the withstand voltage of the source driving circuit 22, etc. Therefore, by overlapping the image signal S2 with the image signal S1, an image corresponding to an image signal whose potential is higher than the potential that the source driving circuit 22 can output can be displayed on the display unit 33. As a result, a high-brightness image can be displayed on the display unit 33. In particular, when the pixel 34 includes a light-emitting element 523 as a display element, a high-brightness image can be displayed on the display unit 33 because a large current can flow through the light-emitting element 523. In addition, the dynamic range of the brightness amplitude of the image that can be displayed by the display unit 33 can be expanded.

[0239] The image corresponding to the image signal S1 and the image corresponding to the image signal S2 may be the same or different. When the image corresponding to the image signal S1 and the image corresponding to the image signal S2 are the same, an image having a brightness higher than that of the image corresponding to the image signal S1 and the image corresponding to the image signal S2 may be displayed on the display unit 33.

[0240] Fig.19 The example in which the image P1 corresponding to the image signal S1 is an image including only text, and the image P2 corresponding to the image signal S2 is an image including a picture and text. In this case, by overlapping the image P1 and the image P2, the brightness of the text can be increased, for example, the text can be emphasized. Fig. 16B As shown, since the potential V is written to the node N2 w After that, the potential of the node N2 changes according to the potential V data Therefore, when rewriting the potential V corresponding to the image signal S2, w In this case, it is necessary to rewrite the potential V of the image signal S1. data On the other hand, when rewriting the potential V data In the case of Fig. 16B The charge written to the node N2 at the time T1 shown is retained without leaking from the transistor 513 and the like, and there is no need to rewrite the potential V w Therefore, in Fig.19 In the case shown, by adjusting the potential V data The value can adjust the brightness of the text.

[0241] Here, as described above, when rewriting the potential V corresponding to the image signal S2 w In this case, it is necessary to rewrite the potential V corresponding to the image signal S1. data On the other hand, when rewriting the potential V data No need to rewrite the potential V w Therefore, the rewriting frequency of the image P2 is preferably lower than the rewriting frequency of the image P1. Note that the image P1 is not limited to an image including only text, and the image P2 is not limited to an image including a picture and text.

[0242] <Cross-sectional structure example of display device>

[0243] Fig. 20 701 and 705 are cross-sectional views showing a structural example of the display device 10. The display device 10 includes a substrate 701 and a substrate 705, and the substrate 701 and the substrate 705 are bonded together using a sealant 712.

[0244] A single crystal semiconductor substrate such as a single crystal silicon substrate can be used as the substrate 701. Alternatively, a semiconductor substrate other than a single crystal semiconductor substrate can be used as the substrate 701.

[0245] A transistor 441 and a transistor 601 are disposed on the substrate 701. The transistor 441 may be a transistor disposed in the circuit 40. The transistor 601 may be a transistor disposed in the gate drive circuit 21 or a transistor disposed in the source drive circuit 22. That is, the transistor 441 and the transistor 601 may be disposed in Figure 1 In layer 20 shown in the above figure.

[0246] The transistor 441 is composed of a conductor 443 serving as a gate electrode, an insulator 445 serving as a gate insulator, and a portion of the substrate 701, and includes a semiconductor region 447 including a channel formation region, a low resistance region 449a serving as one of a source region and a drain region, and a low resistance region 449b serving as the other of the source region and the drain region. The transistor 441 may be a p-channel type or an n-channel type.

[0247] The transistor 441 is electrically isolated from other transistors by the element isolation layer 403 . Fig. 20 The transistor 441 and the transistor 601 are electrically isolated from each other via the element isolation layer 403. The element isolation layer 403 can be formed by a LOCOS (LOCal Oxidation of Silicon) method, an STI (Shallow Trench Isolation) method, or the like.

[0248] Here, in Fig. 20 In the transistor 441 shown in FIG. 1 , the semiconductor region 447 has a convex shape. In addition, the side surface and the top surface of the semiconductor region 447 are covered by the conductor 443 via the insulator 445. Note that Fig. 20 The conductor 443 is not shown in the figure, and covers the side surface of the semiconductor region 447. Alternatively, the conductor 443 may be made of a material that adjusts the work function.

[0249] A transistor in which the semiconductor region has a convex shape, such as transistor 441, can be called a fin-type transistor because the convex portion of the semiconductor substrate is used. In addition, an insulator used as a mask for forming the convex portion may be provided in a manner that contacts the top surface of the convex portion. Fig. 20 7 shows a case where a portion of the substrate 701 is processed to form a protrusion, but an SOI substrate may be processed to form a semiconductor having a protrusion.

[0250] also, Fig. 20 The structure of the transistor 441 shown is only an example and is not limited to this structure, and an appropriate structure may be adopted according to a circuit structure or a circuit operation method, etc. For example, the transistor 441 may be a planar transistor.

[0251] The transistor 601 can have the same structure as the transistor 441 .

[0252] In addition to the element isolation layer 403, the transistor 441, and the transistor 601, the insulator 405, the insulator 407, the insulator 409, and the insulator 411 are provided over the substrate 701. The conductor 451 is embedded in the insulator 405, the insulator 407, the insulator 409, and the insulator 411. Here, the height of the top surface of the conductor 451 and the height of the top surface of the insulator 411 can be made substantially the same.

[0253] Insulator 413 and insulator 415 are provided on conductor 451 and insulator 411. Conductor 457 is embedded in insulator 413 and insulator 415. Conductor 457 may be provided at Fig.13 The wiring 121 and the wiring 123 are shown in the same layer. Here, the height of the top surface of the conductor 457 and the height of the top surface of the insulator 415 can be made substantially the same.

[0254] Insulator 417 and insulator 419 are provided on conductor 457 and insulator 415. Conductor 459 is embedded in insulator 417 and insulator 419. Conductor 459 may be provided at Fig.13 The wiring 141 and the wiring 143 are shown in the same layer. Here, the height of the top surface of the conductor 459 and the height of the top surface of the insulator 419 can be made substantially the same.

[0255] The insulator 421 and the insulator 214 are provided on the conductor 459 and the insulator 419. The conductor 453 is embedded in the insulator 421 and the insulator 214. Here, the height of the top surface of the conductor 453 and the height of the top surface of the insulator 214 can be made substantially the same.

[0256] An insulator 216 is provided on the conductor 453 and the insulator 214. The conductor 455 is embedded in the insulator 216. Here, the height of the top surface of the conductor 455 and the height of the top surface of the insulator 216 can be made substantially the same.

[0257] Insulator 222, insulator 224, insulator 254, insulator 244, insulator 280, insulator 274, and insulator 281 are provided on conductor 455 and insulator 216. Conductor 305 is embedded in insulator 222, insulator 224, insulator 254, insulator 244, insulator 280, insulator 274, and insulator 281. Here, the height of the top surface of conductor 305 and the height of the top surface of insulator 281 can be made substantially the same.

[0258] An insulator 361 is provided on the conductor 305 and the insulator 281. The conductor 317 and the conductor 337 are embedded in the insulator 361. Here, the height of the top surface of the conductor 337 and the height of the top surface of the insulator 361 can be made substantially the same.

[0259] An insulator 363 is provided on the conductor 337 and the insulator 361. The conductors 347, 353, 355, and 357 are embedded in the insulator 363. Here, the height of the top surface of the conductors 353, 355, and 357 can be made substantially the same as the height of the top surface of the insulator 363.

[0260] A connection electrode 760 is provided on the conductor 353, the conductor 355, the conductor 357, and the insulator 363. In addition, an anisotropic conductor 780 is provided so as to be electrically connected to the connection electrode 760, and an FPC (Flexible Printed Circuit) 716 is provided so as to be electrically connected to the anisotropic conductor 780. By using the FPC 716, various signals and the like can be supplied to the display device 10 from the outside of the display device 10.

[0261] like Fig. 20 As shown, the low resistance region 449b serving as the other of the source region and the drain region of the transistor 441 is electrically connected to the FPC 716 through the conductor 451, the conductor 457, the conductor 459, the conductor 453, the conductor 455, the conductor 305, the conductor 317, the conductor 337, the conductor 347, the conductor 353, the conductor 355, the conductor 357, the connection electrode 760 and the anisotropic conductor 780. Fig. 20, three conductors, conductor 353, conductor 355, and conductor 357, are shown as conductors having the function of electrically connecting connection electrode 760 and conductor 347, but one embodiment of the present invention is not limited thereto. The number of conductors having the function of electrically connecting connection electrode 760 and conductor 347 may be one, two, or four or more. By providing a plurality of conductors having the function of electrically connecting connection electrode 760 and conductor 347, contact resistance can be reduced.

[0262] A transistor 750 is disposed on the insulator 214. The transistor 750 may be a transistor disposed in the pixel 34. That is, the transistor 750 may be disposed in Figure 1 In the layer 30 shown in the figure, an OS transistor can be used as the transistor 750. The OS transistor has a characteristic of extremely low off-state current. Thus, the image signal can be maintained for a long time, thereby reducing the refresh frequency. Thus, the power consumption of the display device 10 can be reduced.

[0263] Conductors 301a and 301b are embedded in insulators 254, 244, 280, 274, and 281. Conductor 301a is electrically connected to one of the source and drain of transistor 750, and conductor 301b is electrically connected to the other of the source and drain of transistor 750. Here, the height of the top surface of conductors 301a and 301b can be made substantially the same as the height of the top surface of insulator 281.

[0264] The conductor 311, the conductor 313, the conductor 331, the capacitor 790, the conductor 333, and the conductor 335 are embedded in the insulator 361. The conductors 311 and 313 are electrically connected to the transistor 750 and serve as wiring. The conductors 333 and 335 are electrically connected to the capacitor 790. Here, the height of the top surface of the conductor 331, the conductor 333, and the conductor 335 can be made substantially the same as the height of the top surface of the insulator 361.

[0265] The conductors 341, 343, and 351 are embedded in the insulator 363. Here, the height of the top surface of the conductor 351 and the height of the top surface of the insulator 363 can be made substantially the same.

[0266] Insulators 405, 407, 409, 411, 413, 415, 417, 419, 421, 214, 280, 274, 281, 361, and 363 may be used as interlayer films or as planarization films that cover the concave and convex shapes thereunder. For example, in order to improve the planarity of the top surface of insulator 363, its surface may be planarized by planarization treatment such as chemical mechanical polishing (CMP).

[0267] like Fig. 20 As shown, capacitor 790 includes a lower electrode 321 and an upper electrode 325. In addition, an insulator 323 is provided between the lower electrode 321 and the upper electrode 325. That is, capacitor 790 has a stacked structure in which an insulator 323 serving as a dielectric is sandwiched between a pair of electrodes. In addition, although Fig. 20 Although an example in which the capacitor 790 is provided on the insulator 281 is shown, the capacitor 790 may be provided on an insulator different from the insulator 281 .

[0268] Fig. 20 An example is shown in which conductor 301a, conductor 301b, and conductor 305 are formed in the same layer. In addition, an example is shown in which conductor 311, conductor 313, conductor 317, and lower electrode 321 are formed in the same layer. In addition, an example is shown in which conductor 331, conductor 333, conductor 335, and conductor 337 are formed in the same layer. In addition, an example is shown in which conductor 341, conductor 343, and conductor 347 are formed in the same layer. In addition, an example is shown in which conductor 351, conductor 353, conductor 355, and conductor 357 are formed in the same layer. In this way, by forming a plurality of conductors in the same layer, the manufacturing process of display device 10 can be simplified, thereby providing inexpensive display device 10. In addition, they can also be formed in different layers and contain different kinds of materials.

[0269] Fig. 20 The display device 10 shown includes a liquid crystal element 775. The liquid crystal element 775 includes a conductor 772, a conductor 774, and a liquid crystal layer 776 between the conductor 772 and the conductor 774. The conductor 774 is arranged on one side of the substrate 705 and is used as a common electrode. In addition, the conductor 772 is electrically connected to the other of the source and the drain of the transistor 750 through the conductor 351, the conductor 341, the conductor 331, the conductor 313, and the conductor 301b. The conductor 772 is formed on the insulator 363 and is used as a pixel electrode.

[0270] A material that is translucent to visible light or a material that is reflective can be used as the conductor 772. As the translucent material, for example, an oxide material containing indium, zinc, tin, etc. can be used. As the reflective material, for example, a material containing aluminum, silver, etc. can be used.

[0271] When a reflective material is used as the conductor 772, the display device 10 is a reflective liquid crystal display device. In addition, when a light-transmitting material is used as the conductor 772 and a light-transmitting material is used as the substrate 701, etc., the display device 10 is a transmissive liquid crystal display device. When the display device 10 is a reflective liquid crystal display device, a polarizing plate is provided on the viewing side. In addition, when the display device 10 is a transmissive liquid crystal display device, a pair of polarizing plates are provided in a manner of sandwiching a liquid crystal element.

[0272] Although Fig. 20 Although not shown in the figure, an alignment film may be provided in contact with the liquid crystal layer 776. In addition, an optical member (optical substrate) such as a polarizing member, a phase difference member, an antireflection member, and a light source such as a backlight or a sidelight may be provided as appropriate.

[0273] A structure 778 is provided between the insulator 363 and the conductor 774. The structure 778 is a columnar spacer and is provided to control the distance (cell gap) between the substrate 701 and the substrate 705. Alternatively, a spherical spacer can be used as the structure 778.

[0274] A light shielding layer 738, a coloring layer 736, and an insulator 734 in contact with the light shielding layer 738 are provided on one side of the substrate 705. The light shielding layer 738 has a function of shielding light emitted from an adjacent region. Alternatively, the light shielding layer 738 has a function of preventing external light from reaching the transistor 750 and the like. In addition, the coloring layer 736 has a region overlapping with the liquid crystal element 775.

[0275] The liquid crystal layer 776 may use thermotropic liquid crystal, low molecular liquid crystal, polymer liquid crystal, polymer dispersed liquid crystal (PDLC: Polymer Dispersed Liquid Crystal), polymer network liquid crystal (PNLC: Polymer Network Liquid Crystal), ferroelectric liquid crystal, antiferroelectric liquid crystal, etc. In addition, when the horizontal electric field method is adopted, liquid crystal exhibiting a blue phase that does not require an alignment film may also be used.

[0276] As the mode of the liquid crystal device, a TN (Twisted Nematic) mode, a VA (Vertical Alignment) mode, an IPS (In-Plane-Switching) mode, an FFS (Fringe Field Switching) mode, an ASM (Axially Symmetric aligned Micro-cell) mode, an OCB (Optically Compensated Birefringence) mode, an ECB (Electrically Controlled Birefringence) mode, a guest-host mode, or the like can be used.

[0277] The liquid crystal layer 776 may be a dispersed liquid crystal such as a polymer dispersed liquid crystal or a polymer network liquid crystal. In this case, a structure may be used for black and white display without providing the coloring layer 736, or a structure may be used for color display with the coloring layer 736.

[0278] As a driving method of the liquid crystal device, a time-sharing display method (also called a field sequential driving method) that uses a sequential additive color mixing method to perform color display can be applied. In this case, a structure without a coloring layer 736 can be adopted. When the time-sharing display method is adopted, for example, there is no need to set sub-pixels that respectively present R (red), G (green), and B (blue), so there is an advantage that the aperture ratio and clarity of the pixel can be improved.

[0279] Although Fig. 20 The display device 10 shown uses a liquid crystal element as a display element, but one embodiment of the present invention is not limited to this. Fig.21 yes Fig. 20 A modified example of the display device 10 shown in FIG. Fig.21 and Fig. 20 The display device 10 shown is different in that a light-emitting element is used as a display element.

[0280] Fig.21 The display device 10 shown includes a light-emitting element 782. The light-emitting element 782 includes a conductor 772, an EL layer 786, and a conductor 788. The EL layer 786 includes an organic compound or an inorganic compound such as quantum dots.

[0281] Examples of materials that can be used for the organic compound include fluorescent materials and phosphorescent materials, etc. Examples of materials that can be used for quantum dots include colloidal quantum dots, alloy quantum dots, core-shell quantum dots, and core-type quantum dots.

[0282] Fig.21 The display device 10 shown in the figure has an insulator 730 disposed on the insulator 363. Here, the insulator 730 may cover a portion of the conductor 772. In addition, the light emitting element 782 may include a light-transmitting conductor 788 and be a top-emitting light emitting element. In addition, the light emitting element 782 may also adopt a bottom-emitting structure that emits light to one side of the conductor 772 or a double-sided emission structure that emits light to both sides of the conductor 772 and the conductor 788.

[0283] The light-emitting element 782 may have a microcavity structure, which will be described in detail later. Thus, light of a specified color (e.g., RGB) can be extracted even without a coloring layer, so that the display device 10 can display in color. By adopting a structure in which a coloring layer is not provided, absorption of light by the coloring layer can be suppressed. Thus, the display device 10 can display a high-brightness image, and the power consumption of the display device 10 can be reduced. In addition, when the EL layer 786 is formed into an island shape in each pixel or the EL layer 786 is formed into a strip shape in each pixel column, that is, when the EL layer 786 is formed by coating separately, a structure in which a coloring layer is not provided can also be adopted.

[0284] In addition, the light shielding layer 738 includes a region overlapping with the insulator 730. In addition, the light shielding layer 738 is covered with the insulator 734. In addition, the sealing layer 732 fills a space between the light emitting element 782 and the insulator 734.

[0285] Furthermore, a structure 778 is provided between the insulator 730 and the EL layer 786. Furthermore, a structure 778 is provided between the insulator 730 and the insulator 734.

[0286] Fig. 22 yes Fig.21 The modified example of the display device 10 shown in FIG. Fig.21 The display device 10 shown is different in that a coloring layer 736 is provided. By providing the coloring layer 736, the color purity of light extracted from the light-emitting element 782 can be improved. Therefore, the display device 10 can display a high-quality image. In addition, since all the light-emitting elements 782 in the display device 10 can be, for example, light-emitting elements that emit white light, it is not necessary to form the EL layer 786 by coating separately, and a high-definition display device 10 can be realized.

[0287] Although in Figure 20 to Figure 22 7 shows a structure in which a transistor 441 and a transistor 601 are provided in which a channel formation region is formed inside a substrate 701 and an OS transistor is stacked over the transistor 441 and the transistor 601 ; however, one embodiment of the present invention is not limited to this. Fig.23 , Fig.24 and Fig.25 They are Fig. 20 , Fig.21 and Fig. 22 A deformation example, and with Figure 20 to Figure 22 The display device 10 shown in the figure is different in that the transistor 750 is stacked not on the transistor 441 and the transistor 601 but on the transistor 602 and the transistor 603 which are OS transistors. That is, Figure 23 to Figure 25 The display device 10 having the structure shown has OS transistors stacked.

[0288] An insulator 613 and an insulator 614 are provided over the substrate 701, and a transistor 602 and a transistor 603 are provided over the insulator 614. Alternatively, a transistor or the like may be provided between the substrate 701 and the insulator 613. For example, a transistor 602 and a transistor 603 may be provided between the substrate 701 and the insulator 613. Figure 20 to Figure 22 The transistor 441 and the transistor 601 shown are the same transistors.

[0289] The transistor 602 may be a transistor provided in the circuit 40. The transistor 603 may be a transistor provided in the gate drive circuit 21 or a transistor provided in the source drive circuit 22. That is, the transistor 602 and the transistor 603 may be provided in Figure 1 In the layer 20 shown in the above. Figure 5 As shown, in the case where the circuit 40 is arranged in the layer 30 , the transistor 602 may be arranged in the layer 30 .

[0290] The transistor 602 and the transistor 603 may be transistors having the same structure as the transistor 750. Alternatively, the transistor 602 and the transistor 603 may be OS transistors having a structure different from that of the transistor 750.

[0291] In addition to the transistor 602 and the transistor 603, an insulator 616, an insulator 622, an insulator 624, an insulator 654, an insulator 644, an insulator 680, an insulator 674, and an insulator 681 are provided on the insulator 614. The conductor 461 is embedded in the insulator 654, the insulator 644, the insulator 680, the insulator 674, and the insulator 681. Here, the height of the top surface of the conductor 461 and the height of the top surface of the insulator 681 can be made substantially the same.

[0292] An insulator 501 is provided on the conductor 461 and the insulator 681. The conductor 463 is embedded in the insulator 501. Here, the height of the top surface of the conductor 463 and the height of the top surface of the insulator 501 can be made substantially the same.

[0293] An insulator 503 is provided on the conductor 463 and the insulator 501. The conductor 465 is embedded in the insulator 503. Here, the height of the top surface of the conductor 465 and the height of the top surface of the insulator 503 can be made substantially the same.

[0294] An insulator 505 is provided on the conductor 465 and the insulator 503. The conductor 467 is embedded in the insulator 505. The conductor 467 can be provided at Fig.13 The wiring 121 and the wiring 123 are shown in the same layer. Here, the height of the top surface of the conductor 467 and the height of the top surface of the insulator 505 can be made substantially the same.

[0295] An insulator 507 is provided on the conductor 467 and the insulator 505. The conductor 469 is embedded in the insulator 507. Here, the height of the top surface of the conductor 469 and the height of the top surface of the insulator 507 can be made substantially the same.

[0296] An insulator 509 is provided on the conductor 469 and the insulator 507. A conductor 471 is embedded in the insulator 509. The conductor 471 may be provided at a position similar to Fig.13 The wiring 141 and the wiring 143 are shown in the same layer. Here, the height of the top surface of the conductor 471 and the height of the top surface of the insulator 509 can be made substantially the same.

[0297] The insulator 421 and the insulator 214 are provided on the conductor 471 and the insulator 509. The conductor 453 is embedded in the insulator 421 and the insulator 214. Here, the height of the top surface of the conductor 453 and the height of the top surface of the insulator 214 can be made substantially the same.

[0298] like Figure 23 to Figure 25 As shown, one of the source and drain of transistor 602 is electrically connected to FPC716 through conductor 461, conductor 463, conductor 465, conductor 467, conductor 469, conductor 471, conductor 453, conductor 455, conductor 305, conductor 317, conductor 337, conductor 347, conductor 353, conductor 355, conductor 357, connecting electrode 760 and anisotropic conductor 780.

[0299] Insulator 613 , insulator 614 , insulator 680 , insulator 674 , insulator 681 , insulator 501 , insulator 503 , insulator 505 , insulator 507 , and insulator 509 are used as interlayer films, and can also be used as planarization films that cover the concave and convex shapes thereunder.

[0300] By adopting Figure 23 to Figure 25The structure of the display device 10 shown can use OS transistors as all transistors in the display device 10 while achieving narrow frame and miniaturization of the display device 10. Thus, for example, the transistors provided in the layer 20 and the transistors provided in the layer 30 can be manufactured using the same equipment. Thus, the manufacturing cost of the display device 10 can be reduced, and an inexpensive display device 10 can be provided.

[0301] <Structural Example of Light Emitting Element>

[0302] FIG. 26A to FIG. 26E A structural example of the light-emitting element 782 is shown. Fig.26A A structure (single-layer structure) is shown in which an EL layer 786 is sandwiched between a conductor 772 and a conductor 788. As described above, the EL layer 786 contains a light-emitting material, for example, a light-emitting material containing an organic compound.

[0303] Fig.26B is a diagram showing a stacked structure of the EL layer 786. Fig.26B In the light-emitting element 782 having the structure shown, the conductor 772 serves as an anode and the conductor 788 serves as a cathode.

[0304] The EL layer 786 has a structure in which a hole injection layer 721, a hole transport layer 722, a light-emitting layer 723, an electron transport layer 724, and an electron injection layer 725 are stacked in this order over the conductor 772. When the conductor 772 is used as a cathode and the conductor 788 is used as an anode, the stacking order is reversed.

[0305] The light-emitting layer 723 may have a structure capable of obtaining fluorescent light and phosphorescent light of a desired light color by appropriately combining light-emitting materials and a plurality of materials. In addition, the light-emitting layer 723 may also have a stacked structure with different light-emitting colors. In this case, the light-emitting substances or other substances used for each stacked light-emitting layer may be different materials.

[0306] In the light emitting element 782, for example, by using Fig.26B The conductor 772 shown is a reflective electrode, the conductor 788 is a transflective electrode, and an optical microcavity resonator (microcavity) structure is adopted, so that the light obtained from the light-emitting layer 723 in the EL layer 786 can resonate between the above-mentioned electrodes, thereby enhancing the light emitted through the conductor 788.

[0307] In the case where the conductor 772 of the light emitting element 782 is a reflective electrode composed of a laminated structure of a reflective conductive material and a light-transmitting conductive material (transparent conductive film), optical adjustment can be performed by adjusting the thickness of the transparent conductive film. Specifically, it is preferable to adjust in the following manner: relative to the wavelength λ of the light obtained from the light emitting layer 723, the inter-electrode distance between the conductor 772 and the conductor 788 is about mλ / 2 (note that m is a natural number).

[0308] In order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 723, it is preferable to adjust the optical distance from the conductor 772 to the region (light-emitting region) where the desired light of the light-emitting layer can be obtained and the optical distance from the conductor 788 to the region (light-emitting region) where the desired light of the light-emitting layer 723 can be obtained to about (2m'+1)λ / 4 (note that m' is a natural number). Note that the "light-emitting region" described here refers to the region where holes and electrons in the light-emitting layer 723 recombine.

[0309] By performing the above optical adjustment, the spectrum of specific monochromatic light that can be obtained from the light-emitting layer 723 can be narrowed, thereby obtaining light emission with good color purity.

[0310] Note that in the above case, strictly speaking, the optical distance between the conductor 772 and the conductor 788 can be said to be the total thickness from the reflection area in the conductor 772 to the reflection area in the conductor 788. However, since it is difficult to accurately determine the position of the reflection area in the conductor 772 or the conductor 788, the above effect can be fully obtained by assuming that an arbitrary position in the conductor 772 and the conductor 788 is a reflection area. In addition, strictly speaking, the optical distance between the conductor 772 and the light-emitting layer capable of obtaining the desired light can be said to be the optical distance between the reflection area in the conductor 772 and the light-emitting area in the light-emitting layer capable of obtaining the desired light. However, since it is difficult to accurately determine the position of the reflection area in the conductor 772 or the light-emitting area in the light-emitting layer capable of obtaining the desired light, the above effect can be fully obtained by assuming that an arbitrary position in the conductor 772 is a reflection area and an arbitrary position in the light-emitting layer capable of obtaining the desired light is a light-emitting area.

[0311] Fig.26B The light-emitting element 782 shown has a microcavity structure, so even with the same EL layer, light of different wavelengths (monochromatic light) can be extracted. Thus, in order to obtain different luminous colors, it is not necessary to apply them separately (for example, apply them as R, G, B). Thus, high definition is easily achieved. In addition, it can be combined with a coloring layer. In addition, the luminous intensity in the front direction with a specific wavelength can be enhanced, thereby achieving low power consumption.

[0312] Fig.26B The light-emitting element 782 shown may not have a microcavity structure. In this case, by making the light-emitting layer 723 emit white light and providing a coloring layer, light of a predetermined color (such as RGB) can be extracted. In addition, when the EL layer 786 is formed, by coating separately to obtain different luminescent colors, light of a predetermined color can be extracted without providing a coloring layer.

[0313] At least one of the conductor 772 and the conductor 788 may be a light-transmitting electrode (transparent electrode, transflective electrode, etc.). When the light-transmitting electrode is a transparent electrode, the visible light transmittance of the transparent electrode is 40% or more. In addition, when the electrode is a transflective electrode, the visible light reflectance of the transflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. In addition, the resistivity of these electrodes is preferably 1×10 -2 Ωcm or less.

[0314] When the conductor 772 or the conductor 788 is a reflective electrode (reflective electrode), the reflectivity of the reflective electrode for visible light is 40% or more and 100% or less, preferably 70% or more and 100% or less. In addition, the resistivity of the electrode is preferably 1×10 -2 Ωcm or less.

[0315] The structure of the light emitting element 782 can be Fig.26C The structure shown. Fig.26C A light-emitting element 782 having a stacked structure (tandem structure) is shown in which two EL layers (EL layer 786a and EL layer 786b) are provided between a conductor 772 and a conductor 788 and a charge generation layer 792 is provided between the EL layer 786a and the EL layer 786b. By making the light-emitting element 782 have a tandem structure, the current efficiency and external quantum efficiency of the light-emitting element 782 can be improved. Thus, a high-brightness image can be displayed on the display device 10. In addition, the power consumption of the display device 10 can be reduced. Here, the EL layer 786a and the EL layer 786b can have the same Fig.26B The EL layer 786 has the same structure as shown.

[0316] The charge generation layer 792 has a function of injecting electrons into one of the EL layer 786a and the EL layer 786b and injecting holes into the other when a voltage is applied to the conductor 772 and the conductor 788. Therefore, when a voltage is applied so that the potential of the conductor 772 is higher than that of the conductor 788, electrons are injected from the charge generation layer 792 into the EL layer 786a and holes are injected into the EL layer 786b.

[0317] In terms of light extraction efficiency, the charge generation layer 792 preferably transmits visible light (specifically, the visible light transmittance of the charge generation layer 792 is 40% or more). The charge generation layer 792 may have lower conductivity than the conductor 772 or the conductor 788 .

[0318] The structure of the light emitting element 782 can be Fig.26D The structure shown. Fig.26D The light-emitting element 782 having a tandem structure is shown in which three EL layers (EL layer 786a, EL layer 786b, and EL layer 786c) are provided between the conductor 772 and the conductor 788, and a charge generation layer 792 is provided between the EL layer 786a and the EL layer 786b and between the EL layer 786b and the EL layer 786c. Here, the EL layer 786a, the EL layer 786b, and the EL layer 786c may have the same Fig.26B The EL layer 786 shown in FIG. 7 is similar in structure to the EL layer 786 shown in FIG. Fig.26D The structure shown can further improve the current efficiency and external quantum efficiency of the light-emitting element 782. As a result, a higher brightness image can be displayed on the display device 10. In addition, the power consumption of the display device 10 can be further reduced.

[0319] The structure of the light emitting element 782 can be Fig.26E The structure shown. Fig.26E The light-emitting element 782 having a tandem structure is shown in which n EL layers (EL layers 786(1) to 786(n)) are provided between the conductor 772 and the conductor 788, and a charge generation layer 792 is provided between each EL layer 786. Here, the EL layers 786(1) to 786(n) may have the same Fig.26B The EL layer 786 has the same structure as shown. Fig.26E EL layer 786 (1), EL layer 786 (m), and EL layer 786 (n) in EL layer 786 are shown. Here, m is an integer greater than 2 and less than n, and n is an integer greater than m. As the value of n increases, the current efficiency and external quantum efficiency of light-emitting element 782 can be improved. As a result, a high-brightness image can be displayed on display device 10. In addition, power consumption of display device 10 can be reduced.

[0320] <Materials for Light Emitting Element>

[0321] Next, constituent materials that can be used for the light-emitting element 782 are described.

[0322] 《Conductor 772 and Conductor 788》

[0323] As the conductor 772 and the conductor 788, if the functions of the anode and the cathode can be satisfied, the following materials can be appropriately combined. For example, metals, alloys, conductive compounds and mixtures thereof can be appropriately used. Specifically, In-Sn oxide (also called ITO), In-Si-Sn oxide (also called ITSO), In-Zn oxide, and In-W-Zn oxide can be cited. In addition to the above, aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd) and other metals and alloys appropriately combined therewith can also be cited. In addition to the above, elements belonging to Group 1 or Group 2 of the periodic table (for example, lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu), ytterbium (Yb), alloys appropriately combined therefrom, and graphene, etc. can be used.

[0324] 《Hole injection layer 721 and hole transport layer 722》

[0325] The hole injection layer 721 is a layer that injects holes from the anode conductor 772 or the charge generation layer 792 into the EL layer 786, and contains a material with high hole injection properties. Here, the EL layer 786 includes an EL layer 786a, an EL layer 786b, an EL layer 786c, and an EL layer 786(1) to an EL layer 786(n).

[0326] As materials with high hole injection properties, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can be cited. In addition to the above, phthalocyanine compounds such as phthalocyanine (abbreviated as: H 2 Pc), copper phthalocyanine (CuPC), etc.; aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as: DNTPD), etc.; or polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrene sulfonic acid) (abbreviated as: PEDOT / PSS), etc.

[0327] As a material with high hole injection properties, a composite material containing a hole transport material and an acceptor material (electron acceptor material) can also be used. In this case, the acceptor material extracts electrons from the hole transport material and generates holes in the hole injection layer 721, and the holes are injected into the light-emitting layer 723 through the hole transport layer 722. In addition, the hole injection layer 721 can be a single layer composed of a composite material containing a hole transport material and an acceptor material (electron acceptor material), or a stack of layers formed using hole transport materials and acceptor materials (electron acceptor materials) respectively.

[0328] The hole transport layer 722 is a layer that transports holes injected from the conductor 772 through the hole injection layer 721 to the light-emitting layer 723. The hole transport layer 722 is a layer containing a hole transport material. As the hole transport material used for the hole transport layer 722, it is particularly preferred to use a material having a HOMO energy level that is the same as or close to the HOMO energy level of the hole injection layer 721.

[0329] As an acceptor material for the hole injection layer 721, an oxide of a metal belonging to Group 4 to Group 8 of the periodic table can be used. Specifically, molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide can be mentioned. Molybdenum oxide is particularly preferably used because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle. In addition to the above, organic acceptors such as quinone dimethane derivatives, tetrachlorobenzoquinone derivatives, and hexaazatriphenylene derivatives can be mentioned. Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as: F 4 -TCNQ), tetrachlorobenzoquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as: HAT-CN), etc.

[0330] As the hole transport material used for the hole injection layer 721 and the hole transport layer 722, it is preferable to have 10 - 6 cm 2 In addition, any substance other than the above may be used as long as the hole transport property is higher than the electron transport property.

[0331] As hole transport materials, it is preferred to use π-electron-rich heteroaromatic compounds (for example, carbazole derivatives or indole derivatives) or aromatic amine compounds, and specific examples are as follows: 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as: NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as: TPD), 4,4'-bis[N-(spiro-9,9'-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviated as: BSPB), 4-phenyl-4'-(9-phenylfluorene)- -9-yl) triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl) triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl) triphenylamine (abbreviation: PCBA1BP), 3-[4-(9-phenanthrenyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9-phenyl-9H-carbazole-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N- [4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9 Compounds having an aromatic amine skeleton such as 4-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)spiro-9,9'-difluoren-2-amine (PCBAF), 4,4',4"-tris(carbazol-9-yl)triphenylamine (TCTA), 4,4',4"-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4"-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (MTDATA);1,3-Bis(N-carbazolyl)benzene (mCP), 4,4'-bis(N-carbazolyl)biphenyl (CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (PCCP), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (PCz PCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviated as PCzPCN1), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), 9-[4-(10-phenyl-9- compounds having a carbazole skeleton, such as 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III), Compounds having a thiophene skeleton such as 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II).

[0332] Furthermore, high molecular weight compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used.

[0333] Note that the hole transport material is not limited to the above materials, and one or more known various materials can be combined and used as the hole transport material for the hole injection layer 721 and the hole transport layer 722. In addition, the hole transport layer 722 can also be composed of a plurality of layers. That is, for example, a first hole transport layer and a second hole transport layer can also be stacked.

[0334] 《Luminous Layer 723》

[0335] The light-emitting layer 723 is a layer containing a light-emitting substance. In addition, as the light-emitting substance, a substance that emits light of a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. Fig.26C , Fig.26D and Fig.26E As shown in FIG. 1 , when the light-emitting element 782 has a plurality of EL layers, by using different light-emitting substances in the light-emitting layers 723 provided in each EL layer, a structure showing different luminescent colors can be achieved (for example, luminescent colors in a complementary color relationship can be combined to obtain white luminescence). Fig.26C In the case of the structure shown in FIG. 1 , by using different light-emitting materials between the light-emitting layer 723 provided in the EL layer 786a and the light-emitting layer 723 provided in the EL layer 786b, the light-emitting color of the EL layer 786a can be made different from the light-emitting color of the EL layer 786b. Alternatively, a stacked structure in which one light-emitting layer has different light-emitting materials may be used.

[0336] The light-emitting layer 723 may contain one or more organic compounds (host material, auxiliary material) in addition to the light-emitting substance (guest material). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material can be used.

[0337] The light emitting element 782 has Fig.26C In the case of the structure shown, it is preferred that a light-emitting substance that emits blue light (blue light-emitting substance) is used as a guest material in either the EL layer 786a or the EL layer 786b, and a substance that emits green light (green light-emitting substance) and a substance that emits red light (red light-emitting substance) are used in the other. This method is effective when the luminous efficiency and service life of the blue light-emitting substance (blue light-emitting layer) are lower or shorter than those of other colors. In addition, here, when a light-emitting substance that converts singlet excitation energy into light in the visible light region is used as the blue light-emitting substance and a light-emitting substance that converts triplet excitation energy into light in the visible light region is used as the green and red light-emitting substances, the spectrum balance of RGB is well exerted, so it is preferred.

[0338] There are no particular limitations on the light-emitting material that can be used for the light-emitting layer 723, and a light-emitting material that converts singlet excitation energy into light in the visible light region or a light-emitting material that converts triplet excitation energy into light in the visible light region can be used. Examples of the light-emitting material include the following.

[0339] As the luminescent substance that converts the singlet excitation energy into luminescence, there can be mentioned substances that emit fluorescence (fluorescent materials), for example, pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, naphthalene derivatives, etc. In particular, pyrene derivatives are preferred because of their high luminescence quantum yield. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N'-bis(dibenzothiophene-2-yl)-N,N' -diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), etc. In addition, pyrene derivatives are a group of compounds that are effective for achieving the blue chromaticity in one embodiment of the present invention.

[0340] In addition to the above, 5,6-bis[4-(10-phenyl-9-anthracenyl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthracenyl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: Y GA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthracenyl)triphenylamine (abbreviated as: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthracenyl)triphenylamine (abbreviated as: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole-3-amine (abbreviated as: PCAPA), 4-(10-phenyl triphenylamine (PCBAPA), 4-[4-(10-phenyl-9-anthracenyl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (PCBAPBA), perylene, 2,5,8,11-tetra(tert-butyl) perylene (TBP), N,N"-(2-tert-butylanthracene-9,10-diyldi- 4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviated as DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthracenyl)phenyl]-9H-carbazole-3-amine (abbreviated as 2PCAPPA), N-[4-(9,10-diphenyl-2-anthracenyl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as 2DPAPPA), etc.

[0341] Examples of the light-emitting substance that converts triplet excitation energy into light emission include substances that emit phosphorescence (phosphorescent materials) and thermally activated delayed fluorescence (TADF) materials that exhibit thermally activated delayed fluorescence.

[0342] Examples of phosphorescent materials include organic metal complexes, metal complexes (platinum complexes), rare earth metal complexes, etc. Since each of these substances exhibits different emission colors (emission peaks), they are appropriately selected and used as required.

[0343] Examples of phosphorescent materials that exhibit blue or green color and have an emission spectrum with a peak wavelength of 450 nm to 570 nm include the following.

[0344] For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviated as [Ir(mpptz-dmp) 3 ]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviated as: [Ir(Mptz) 3 ]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviated as: [Ir(iPrptz-3b) 3 ]), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviated as: [Ir(iPr5btz) 3 ]) and other organic metal complexes with a 4H-triazole skeleton; tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviated as: [Ir(Mptz1-mp) 3 ]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviated as: [Ir(Prptz1-Me) 3 ]) and other organic metal complexes with a 1H-triazole skeleton; fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviated as: [Ir(iPrpmi) 3 ]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviated as [Ir(dmpimpt-Me) 3 ]) and other organic metal complexes having an imidazole skeleton; and bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2 '] iridium (III) tetrakis (1-pyrazolyl) borate (abbreviated as FIr6), bis [2-(4', 6'-difluorophenyl) pyridinium-N, C 2 '] iridium (III) picolinate (abbreviated as FIrpic), bis[2-(3,5-bistrifluoromethylphenyl)-pyridinium-N,C 2 '] iridium (III) picolinate (abbreviated as: [Ir(CF 3 ppy) 2 (pic)]), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2'] iridium (III) acetylacetonate (abbreviated as FIr (acac)) and other organic metal complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands.

[0345] Examples of phosphorescent materials that exhibit green or yellow color and have an emission spectrum with a peak wavelength of 495 nm to 590 nm include the following.

[0346] For example, tris(4-methyl-6-phenylpyrimidine)iridium(III) (abbreviated as [Ir(mppm) 3 ]), tri(4-tert-butyl-6-phenylpyrimidine)iridium(III) (abbreviated as: [Ir(tBuppm) 3 ]), (acetylacetonate)bis(6-methyl-4-phenylpyrimidinyl)iridium(III) (abbreviated as: [Ir(mppm) 2 (acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinyl)iridium(III) (abbreviated as: [Ir(tBuppm) 2 (acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidine]iridium(III) (abbreviated as: [Ir(nbppm) 2 (acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinyl]iridium(III) (abbreviated as: [Ir(mpmppm) 2 (acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviated as: [Ir(dmppm-dmp) 2 (acac)]), (acetylacetonate)bis(4,6-diphenylpyrimidine)iridium(III) (abbreviated as: [Ir(dppm) 2 (acac)]) and other organometallic iridium complexes with a pyrimidine skeleton, (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine)iridium(III) (abbreviated as [Ir(mppr-Me) 2 (acac)]), (acetylacetonate)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium(III) (abbreviated as: [Ir(mppr-iPr) 2 (acac)]) and other organic metal iridium complexes with pyrazine skeletons, tris(2-phenylpyridinium-N,C 2 ') Iridium (III) (abbreviated as: [Ir(ppy) 3 ]), bis(2-phenylpyridinium-N,C 2 ') Iridium (III) acetylacetonate (abbreviated as: [Ir(ppy) 2(acac)]), bis(benzo[h]quinoline)iridium(III)acetylacetonate (abbreviated as: [Ir(bzq) 2 (acac)]), tris(benzo[h]quinoline)iridium(III) (abbreviated as: [Ir(bzq) 3 ]), tris(2-phenylquinoline-N,C 2′ )iridium(III) (abbreviation: [Ir(pq) 3 ]), bis(2-phenylquinoline-N,C 2 ') Iridium(III) acetylacetonate (abbreviated as: [Ir(pq) 2 (acac)]) and other organic metal iridium complexes with a pyridine skeleton, bis(2,4-diphenyl-1,3-oxazol-N,C 2 ') Iridium(III) acetylacetonate (abbreviated as: [Ir(dpo) 2 (acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridine-N,C 2 '}Iridium(III) acetylacetonate (abbreviated as: [Ir(p-PF-ph) 2 (acac)]), bis(2-phenylbenzothiazole-N,C 2 ') Iridium (III) acetylacetonate (abbreviated as: [Ir(bt) 2 (acac)]) and other organic metal complexes, tris(acetylacetonato)(monophanate)terbium(III) (abbreviated as: [Tb(acac) 3 (Phen)]) and other rare earth metal complexes.

[0347] Among the above substances, an organometallic iridium complex having a pyridine skeleton (particularly a phenylpyridine skeleton) or a pyrimidine skeleton is an effective compound group for achieving green chromaticity in one embodiment of the present invention.

[0348] Examples of phosphorescent materials that exhibit yellow or red color and have an emission spectrum with a peak wavelength of 570 nm to 750 nm include the following.

[0349] For example, (diisobutyrylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinyl]iridium(III) (abbreviated as [Ir(5mdppm) 2 (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinyl](dipivaloylmethane)iridium(III) (abbreviated as: [Ir(5mdppm) 2 (dpm)]), (dipivaloylmethane)bis[4,6-di(naphthalene-1-yl)pyrimidinyl]iridium(III) (abbreviated as: [Ir(d1npm) 2(dpm)]) and other organic metal complexes with pyrimidine skeletons; (acetylacetonato)bis(2,3,5-triphenylpyrazine)iridium(III) (abbreviated as: [Ir(tppr) 2 (acac)]), bis(2,3,5-triphenylpyrazine)(dipivaloylmethane)iridium(III) (abbreviated as: [Ir(tppr) 2 (dpm)]), bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedione-κ 2 O,O')iridium(III) (abbreviation: [Ir(dmdppr-P) 2 (dibm)]), bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedione-κ 2 O,O')iridium(III) (abbreviation: [Ir(dmdppr-dmCP) 2 (dpm)]), (acetylacetonato)bis[2-methyl-3-phenylquinoxalinato]-N,C 2’ ]iridium(III) (abbreviation: [Ir(mpq) 2 (acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C 2’ ]iridium(III) (abbreviation: [Ir(dpq) 2 (acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviated as [Ir(Fdpq) 2 (acac)]) and other organic metal complexes with pyrazine skeletons; tris(1-phenylisoquinoline-N,C 2’ )iridium(III) (abbreviation: [Ir(piq) 3 ]), bis(1-phenylisoquinoline-N,C 2 ') Iridium(III) acetylacetonate (abbreviated as: [Ir(piq) 2 (acac)]) and other organic metal complexes with a pyridine skeleton; platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum (II) (abbreviated as [PtOEP]); and tris(1,3-diphenyl-1,3-propanedione (propanedionato))(monophanation)europium(III) (abbreviated as [Eu(DBM) 3(Phen)]), tris[1-(2-thenoyl)-3,3,3-trifluoroacetone](monophanate)europium(III) (abbreviated as: [Eu(TTA) 3 (Phen)]) and other rare earth metal complexes.

[0350] Among the above substances, an organometallic iridium complex having a pyrazine skeleton is an effective compound group for achieving the red chromaticity in one embodiment of the present invention. In particular, an organometallic iridium complex having a cyano group such as [Ir(dmdppr-dmCP) 2 (dpm)] etc. are preferred because of their high stability.

[0351] In addition, as a blue light-emitting substance, a substance having a peak wavelength of photoluminescence of 430 nm or more and 470 nm or less, preferably 430 nm or more and 460 nm or less can be used. In addition, as a green light-emitting substance, a substance having a peak wavelength of photoluminescence of 500 nm or more and 540 nm or less, preferably 500 nm or more and 530 nm or less can be used. In addition, as a red light-emitting substance, a substance having a peak wavelength of photoluminescence of 610 nm or more and 680 nm or less, preferably 620 nm or more and 680 nm or less can be used. In addition, the measurement of photoluminescence can use a solution or a film.

[0352] By using the above-mentioned compound and the microcavity effect at the same time, the above-mentioned chromaticity can be more easily achieved. At this time, the thickness of the transflective electrode (metal film part) required to obtain the microcavity effect is preferably greater than 20nm and less than 40nm, more preferably greater than 25nm and less than 40nm. When the thickness exceeds 40nm, the efficiency may be reduced.

[0353] As the organic compound (host material, auxiliary material) used for the light-emitting layer 723, one or more substances having a larger energy gap than the light-emitting substance (guest material) can be used. In addition, the above-mentioned hole transport material and the electron transport material described later can be used as the host material or the auxiliary material.

[0354] When the luminescent material is a fluorescent material, it is preferred to use an organic compound with a large energy level of a singlet excited state and a small energy level of a triplet excited state as a host material. For example, an anthracene derivative or a tetracene derivative is preferably used. Specifically, 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as: CzPA), 7-[4-(10-phenyl-9-anthracenyl)phenyl]-7H-dibenzo[ c,g] carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthracenyl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluorene-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA), 5,12-diphenyl tetracene, 5,12-bis(biphenyl-2-yl) tetracene, etc.

[0355] In the case where the luminescent material is a phosphorescent material, an organic compound whose triplet excitation energy is larger than the triplet excitation energy (energy difference between the ground state and the triplet excited state) of the luminescent material is selected as the host material. In this case, zinc or aluminum metal complexes, oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, pyrimidine derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, phenanthroline derivatives, etc. or aromatic amines, carbazole derivatives, etc. can be used.

[0356] Specifically, there are tris(8-hydroxyquinoline)aluminum(III) (abbreviated as Alq), tris(4-methyl-8-hydroxyquinoline)aluminum(III) (abbreviated as Almq 3 ), bis(10-hydroxybenzo[h]quinolinolato)beryllium(II) (abbreviated as: BeBq 2), bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviated as ZnPBO), bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ), etc.; 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as OXD-7), 3-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole-2-yl)benzene (abbreviated as OXD-7), etc. heterocyclic compounds such as 2-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2"-(1,3,5-benzenetriyl)-tri(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11); and aromatic amine compounds such as NPB, TPD, and BSPB.

[0357] In addition, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, (chrysene) derivatives, dibenzo[g,p] Condensed polycyclic aromatic compounds such as derivatives. Specifically, 9,10-diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthracenyl)triphenylamine (abbreviation: DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthracenyl)phenyl]phenyl}-9H-carbazole-3-amine (abbreviation: PCAPBA), 9,10-diphenyl-2-[N-phenyl-N-(9-phenyl-9H-carbazole-3-yl)amino]anthracene (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenyl N,N,N',N',N",N",N"',N"'-octaphenyldibenzo[g,p] -2,7,10,15-tetramine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9'-bianthracene (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)phenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)phenanthrene (abbreviation: DPNS2) and 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3), etc.

[0358] In addition, when a plurality of organic compounds are used for the light-emitting layer 723, it is preferred to use a compound that forms an exciplex and a light-emitting substance in combination. In this case, various organic compounds can be appropriately combined for use, but in order to efficiently form an exciplex, it is particularly preferred to combine a compound that easily receives holes (hole transport material) and a compound that easily receives electrons (electron transport material). In addition, as specific examples of hole transport materials and electron transport materials, the materials described in this embodiment can be used.

[0359] TADF material refers to a material that can use tiny thermal energy to up-convert the triplet excited state to the singlet excited state (reverse intersystem crossing) and efficiently present luminescence (fluorescence) from the singlet excited state. The conditions for efficiently obtaining thermally activated delayed fluorescence are as follows: the energy difference between the triplet excited energy level and the singlet excited energy level is greater than 0eV and less than 0.2eV, preferably greater than 0eV and less than 0.1eV. The delayed fluorescence presented by the TADF material refers to luminescence whose spectrum is the same as that of general fluorescence but whose lifetime is very long. The lifetime is 10 -6 More than 10 seconds, preferably 10 -3 seconds or more.

[0360] As TADF materials, for example, fullerene or its derivatives, acridine derivatives such as prussicin, eosin, etc. can be cited. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In) or palladium (Pd) can be cited. As metal-containing porphyrins, for example, protoporphyrin-tin fluoride complex (SnF 2 (Proto IX)), mesoporphyrin-tin fluoride complex (SnF 2 (Meso IX)), hematoporphyrin-tin fluoride complex (SnF 2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF 2 (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF 2 (OEP)), protoporphyrin-tin fluoride complex (SnF 2 (Etio I)) and octaethylporphyrin-platinum chloride complex (PtCl 2 OEP) etc.

[0361] In addition to the above, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazole-11-yl)-1,3,5-triazine (PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (PXZ-TRZ), 3-[4-(5-phenyl)-1,3,5-triazine (PXZ-TRZ), 3-[4-(5-phenyl)-1,3,5-triazine (PXZ-TRZ), 3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl ... The invention relates to heterocyclic compounds having π-electron-rich heteroaromatic rings and π-electron-deficient heteroaromatic rings, such as 1,4-dihydro-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-oxanthene-9-one (ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridinium)phenyl]sulfone (DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (ACRSA). In addition, in a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded, the donor property of the π-electron-rich heteroaromatic ring and the acceptor property of the π-electron-deficient heteroaromatic ring are both strong, and the energy difference between the singlet excited state and the triplet excited state becomes small, so it is particularly preferred.

[0362] Furthermore, when a TADF material is used, it may be used in combination with other organic compounds.

[0363] 《Electron Transport Layer 724》

[0364] The electron transport layer 724 is a layer that transports electrons injected from the conductor 788 through the electron injection layer 725 to the light-emitting layer 723. The electron transport layer 724 is a layer containing an electron transport material. The electron transport material used for the electron transport layer 724 preferably has a 1×10 -6 cm 2 In addition, any substance other than the above may be used as long as the electron transport property is higher than the hole transport property.

[0365] Examples of electron transporting materials include metal complexes having quinoline ligands, benzoquinoline ligands, oxazole ligands, thiazole ligands, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, etc. In addition to the above, π-electron-deficient heteroaromatic compounds such as nitrogen-containing heteroaromatic compounds can also be used.

[0366] Specifically, Alq 3 、Tris(4-methyl-8-hydroxyquinoline)aluminum (abbreviated as: Almq 3 ), bis(10-hydroxybenzo[h]-quinolinolato)beryllium (abbreviated as: BeBq 2 )、BAlq、Zn(BOX) 2 、Bis[2-(2-hydroxyphenyl)-benzothiazole]zinc (abbreviated as: Zn(BTZ) 2 ), metal complexes such as 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), 3-(4'-tert-butylphenyl)-4-phenyl-5-(4"-biphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: Bphen), bathocuproin (abbreviation: BCP), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and the like, heteroaromatic compounds such as 2-[3- Quinoxaline derivatives or dibenzoquinoxaline derivatives such as 2-[(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II) and 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II).

[0367] In addition, polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can also be used.

[0368] The electron-transport layer 724 may have a single-layer structure or a structure in which two or more layers composed of the above-mentioned substances are stacked.

[0369] 《Electron Injection Layer 725》

[0370] The electron injection layer 725 is a layer containing a substance with high electron injection properties. As the electron injection layer 725, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF 2 ) and lithium oxide (LiO x ) or other alkali metals, alkaline earth metals, or compounds of these metals. In addition, erbium fluoride (ErF 3 ) and other rare earth metal compounds. In addition, an electron salt may be used for the electron injection layer 725. As the electron salt, for example, a substance in which electrons are added to a mixed oxide of calcium and aluminum at a high concentration may be cited. In addition, the substance constituting the electron transport layer 724 as described above may also be used.

[0371] In addition, a composite material formed by mixing an organic compound with an electron donor (donor) can also be used for the electron injection layer 725. This composite material has excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material with excellent performance in transporting the generated electrons. Specifically, for example, an electron transport material (metal complex, heteroaromatic compound, etc.) for the electron transport layer 724 as described above can be used. As an electron donor, any substance that exhibits electron donor properties to organic compounds can be used. Specifically, alkali metals, alkaline earth metals and rare earth metals are preferably used, and lithium, cesium, magnesium, calcium, erbium, ytterbium, etc. can be cited. In addition, alkali metal oxides or alkaline earth metal oxides are preferably used, and lithium oxide, calcium oxide, barium oxide, etc. can be cited. In addition, Lewis bases such as magnesium oxide can also be used. In addition, organic compounds such as tetrathiafulvalene (abbreviated as: TTF) can also be used.

[0372] 《Charge Generation Layer 792》

[0373] The charge generation layer 792 has a function of injecting electrons into the EL layer 786 closer to the conductor 772 and injecting holes into the EL layer 786 closer to the conductor 788 of the two EL layers 786 in contact with the charge generation layer 792 when a voltage is applied to the conductor 772 and the conductor 788. Fig.26CIn the light-emitting element 782 of the structure shown, the charge generation layer 792 has the function of injecting electrons into the EL layer 786a and injecting holes into the EL layer 786b. The charge generation layer 792 may have a structure in which an electron acceptor (acceptor) is added to the hole transport material, or may have a structure in which an electron donor (donor) is added to the electron transport material. Alternatively, these two structures may be stacked. In addition, by using the above-mentioned material to form the charge generation layer 792, the increase in the driving voltage of the display device 10 when the EL layer is stacked can be suppressed.

[0374] When the charge generation layer 792 has a structure in which an electron acceptor is added to a hole transport material, the electron acceptor can be 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F 4 -TCNQ), chloranil, etc. In addition, oxides of metals belonging to Groups 4 to 8 of the periodic table can be cited. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, etc. can be cited.

[0375] In the case where the charge generation layer 792 has a structure in which an electron donor is added to an electron transport material, an alkali metal, an alkaline earth metal, a rare earth metal, or a metal belonging to Group 2 or Group 13 in the periodic table and their oxides or carbonates can be used as the electron donor. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, etc. are preferably used. In addition, organic compounds such as tetrathianaphthacene can also be used as electron donors.

[0376] In addition, when manufacturing the light-emitting element 782, a vacuum process such as evaporation or a solution process such as spin coating or inkjet can be used. As an evaporation method, a physical evaporation method (PVD method) or chemical vapor deposition method (CVD method) such as sputtering, ion plating, ion beam evaporation, molecular beam evaporation, vacuum evaporation can be used. In particular, a functional layer (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer) and a charge generation layer included in the EL layer of the light-emitting element can be formed by a method such as evaporation (vacuum evaporation), coating (dip coating, dye coating, rod coating, spin coating, spray coating, etc.), printing (inkjet, screen printing (porcelain printing), offset printing (lithography), flexographic printing (letterpress printing), gravure printing, micro-contact printing, etc.)

[0377] In addition, the materials of the functional layers (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer) and the charge generation layer constituting the EL layer of the light-emitting element shown in this embodiment are not limited thereto, and even materials other than the above can be used in combination as long as the functions of each layer can be satisfied. As an example, polymer compounds (oligomers, dendrimers, polymers, etc.), medium molecular compounds (compounds between low molecules and polymers: molecular weight of 400 to 4000), inorganic compounds (quantum dot materials, etc.), etc. can be used. As quantum dot materials, colloidal quantum dot materials, alloy quantum dot materials, core-shell quantum dot materials, core-type quantum dot materials, etc. can be used.

[0378] At least a part of the structural examples described in this embodiment mode and the drawings and the like corresponding to these examples can be implemented in combination with other structural examples or drawings and the like as appropriate.

[0379] At least a part of this embodiment mode can be implemented in combination with other embodiment modes described in this specification as appropriate.

[0380] (Implementation Method 2)

[0381] In this embodiment, a transistor that can be used for a display device which is one embodiment of the present invention is described.

[0382] <Structural Example 1 of Transistor>

[0383] Fig.27A , Fig.27B and Fig.27C 1 and 2 are top views and cross-sectional views of a transistor 200A and its surroundings that can be used in a display device of one embodiment of the present invention. The transistor 200A can be used as a transistor included in the display portion 33, the gate driver circuit 21, the source driver circuit 22, and the circuit 40 described in Embodiment Mode 1 and the like.

[0384] Fig.27A is a top view of transistor 200A. Fig.27B and Fig.27C is a cross-sectional view of transistor 200A. Fig.27B It is along Fig.27A The cross-sectional view taken along the dashed line A1-A2 in FIG. 1 is equivalent to a cross-sectional view of the transistor 200A in the channel length direction. Fig.27C It is along Fig.27A The cross-sectional view along the dotted line A3-A4 in FIG. 1 is equivalent to the cross-sectional view along the channel width direction of the transistor 200A. Note that for ease of understanding, Fig.27A Some components are omitted in the top view.

[0385] The transistor 200A includes: a metal oxide 230a disposed on a substrate (not shown); a metal oxide 230b disposed on the metal oxide 230a; a conductor 242a and a conductor 242b separated from each other disposed on the metal oxide 230b; an insulator 280 disposed on the conductors 242a and 242b and having an opening formed between the conductors 242a and 242b; a conductor 260 disposed in the opening; an insulator 250 disposed between the metal oxide 230b, the conductor 242a, the conductor 242b, and the insulator 280 and the conductor 260; and a metal oxide 230c disposed between the metal oxide 230b, the conductor 242a, the conductor 242b, and the insulator 280 and the insulator 250. Here, as shown in FIG. Fig.27B and Fig.27C As shown, the top surface of the conductor 260 is preferably substantially consistent with the top surfaces of the insulator 250, the insulator 254, the metal oxide 230c, and the insulator 280. Hereinafter, the metal oxide 230a, the metal oxide 230b, and the metal oxide 230c are sometimes collectively referred to as oxide 230. In addition, the conductor 242a and the conductor 242b are sometimes collectively referred to as conductor 242.

[0386] like Fig.27B As shown, in the transistor 200A, the side surfaces of the conductor 242a and the conductor 242b on the side of the conductor 260 have a substantially vertical shape. In addition, the transistor 200A shown in FIG. 27 is not limited thereto, and a structure in which the angle formed by the side surfaces and the bottom surfaces of the conductors 242a and 242b is greater than 10° and less than 80°, preferably greater than 30° and less than 60° may be adopted. In addition, a structure in which the opposing side surfaces of the conductors 242a and 242b have a plurality of faces may be adopted.

[0387] In addition, if Fig.27B and Fig.27C As shown in FIG. 1 , an insulator 254 is preferably disposed between the insulator 224, the metal oxide 230a, the metal oxide 230b, the conductor 242a, the conductor 242b, the metal oxide 230c, and the insulator 280. Fig.27B , Fig.27C As shown, the insulator 254 preferably has an area in contact with the side of the metal oxide 230c, the top and side of the conductor 242a, the top and side of the conductor 242b, the side of the metal oxide 230a, the side of the metal oxide 230b, and the top surface of the insulator 224.

[0388] Note that in transistor 200A, three layers of metal oxide 230a, metal oxide 230b, and metal oxide 230c are stacked in the region where the channel is formed (hereinafter also referred to as the channel formation region) and its vicinity, but the present invention is not limited to this. For example, a two-layer structure of metal oxide 230b and metal oxide 230c or a stacked structure of four or more layers can be adopted. In addition, in transistor 200A, conductor 260 has a two-layer structure, but the present invention is not limited to this. For example, conductor 260 may also have a single-layer structure or a stacked structure of three or more layers. In addition, metal oxide 230a, metal oxide 230b, and metal oxide 230c may each have a stacked structure of two or more layers.

[0389] For example, when the metal oxide 230c has a stacked structure consisting of a first metal oxide and a second metal oxide on the first metal oxide, the first metal oxide may have the same composition as the metal oxide 230b, and the second metal oxide preferably has the same composition as the metal oxide 230a.

[0390] Here, the conductor 260 is used as the gate electrode of the transistor, and the conductor 242a and the conductor 242b are each used as the source electrode or the drain electrode. As described above, the conductor 260 is formed in a manner that is embedded in the opening of the insulator 280 and is sandwiched between the conductor 242a and the conductor 242b. Here, the configuration of the conductor 260, the conductor 242a, and the conductor 242b is formed in a self-aligned manner relative to the opening of the insulator 280. That is, in the transistor 200A, the gate electrode can be self-aligned between the source electrode and the drain electrode. Thus, the conductor 260 can be formed in a manner that does not provide room for alignment, so the occupied area of ​​the transistor 200A can be reduced. Thus, the high definition of the display device can be achieved. In addition, a display device with a narrow frame can be achieved.

[0391] Furthermore, as shown in FIG. 27 , the conductor 260 preferably includes a conductor 260 a disposed inside the insulator 250 , and a conductor 260 b disposed so as to be embedded inside the conductor 260 a .

[0392] In addition, if Fig.27A , Fig.27B and Fig.27C As shown, the transistor 200A preferably includes an insulator 214 disposed on a substrate (not shown), an insulator 216 disposed on the insulator 214, a conductor 205 disposed in a manner embedded in the insulator 216, an insulator 222 disposed on the insulator 216 and the conductor 205, and an insulator 224 disposed on the insulator 222. A metal oxide 230a is preferably disposed on the insulator 224.

[0393] Insulators 274 and 281 serving as interlayer films are preferably provided over the transistor 200A. Here, the insulator 274 is preferably in contact with the top surfaces of the conductor 260 , the insulator 250 , the insulator 254 , the metal oxide 230 c , and the insulator 280 .

[0394] In addition, the insulator 222, the insulator 254, and the insulator 274 preferably have a function of suppressing the diffusion of at least one of hydrogen (e.g., hydrogen atoms, hydrogen molecules, etc.). For example, the hydrogen permeability of the insulator 222, the insulator 254, and the insulator 274 is preferably lower than that of the insulator 224, the insulator 250, and the insulator 280. In addition, the insulator 222 and the insulator 254 preferably have a function of suppressing the diffusion of at least one of oxygen (e.g., oxygen atoms, oxygen molecules, etc.). For example, the oxygen permeability of the insulator 222 and the insulator 254 is preferably lower than that of the insulator 224, the insulator 250, and the insulator 280.

[0395] Here, the insulator 224, the oxide 230, and the insulator 250 are separated from the insulators 280 and 281 by the insulators 254 and 274. Thus, impurities such as hydrogen and excess oxygen contained in the insulators 280 and 281 can be prevented from being mixed into the insulator 224, the metal oxide 230a, the metal oxide 230b, and the insulator 250.

[0396] In addition, it is preferred to provide a conductor 240 (conductor 240a and conductor 240b) electrically connected to the transistor 200A and used as a plug. In addition, an insulator 241 (insulator 241a and insulator 241b) in contact with the side of the conductor 240 used as a plug is also provided. That is, the insulator 241 is provided in a manner in contact with the inner wall of the opening of the insulator 254, the insulator 280, the insulator 274, and the insulator 281. In addition, a first conductor of the conductor 240 may be provided in contact with the side of the insulator 241 and a second conductor of the conductor 240 may be provided inside the conductor 240. Here, the height of the top surface of the conductor 240 may be substantially the same as the height of the top surface of the insulator 281. In addition, a structure in which the first conductor of the conductor 240 and the second conductor of the conductor 240 are stacked in the transistor 200A is shown, but the present invention is not limited thereto. For example, the conductor 240 may also have a single-layer structure or a stacked structure of three or more layers. When a structure has a stacked structure, it is sometimes distinguished by assigning an ordinal number according to the order of formation.

[0397] In addition, in the transistor 200A, a metal oxide used as an oxide semiconductor (hereinafter also referred to as an oxide semiconductor) is preferably used for the oxide 230 (metal oxide 230a, metal oxide 230b, and metal oxide 230c) including the channel formation region. For example, as the metal oxide that becomes the channel formation region of the oxide 230, a metal oxide having a band gap of 2 eV or more, preferably 2.5 eV or more is preferably used.

[0398] In addition, if Fig.27B As shown, the thickness of the region of the metal oxide 230b that does not overlap with the conductor 242 is sometimes thinner than the thickness of the region that overlaps with the conductor 242. This is because a portion of the top surface of the metal oxide 230b is removed when the conductor 242a and the conductor 242b are formed. When a conductive film that becomes the conductor 242 is formed, a low resistance region is sometimes formed near the interface between the top surface of the metal oxide 230b and the conductive film. In this way, by removing the low resistance region between the conductor 242a and the conductor 242b on the top surface of the metal oxide 230b, the formation of a channel in this region can be suppressed.

[0399] By one embodiment of the present invention, a display device including a small-sized transistor and having high definition can be provided. In addition, a display device including a transistor with a large on-state current and having high brightness can be provided. In addition, a display device including a transistor with a fast operating speed and having a fast operating speed can be provided. In addition, a display device including a transistor with stable electrical characteristics and having high reliability can be provided. In addition, a display device including a transistor with a small off-state current and having low power consumption can be provided.

[0400] A detailed structure of a transistor 200A that can be used in a display device according to one embodiment of the present invention will be described.

[0401] The conductor 205 is configured to include an area overlapping with the oxide 230 and the conductor 260. In addition, the conductor 205 is preferably provided in a manner embedded in the insulator 216. Here, the flatness of the top surface of the conductor 205 is preferably high. For example, the average surface roughness (Ra) of the top surface of the conductor 205 is 1 nm or less, preferably 0.5 nm or less, and more preferably 0.3 nm or less. Thus, the flatness of the insulator 224 formed on the conductor 205 can be improved, and the crystallinity of the metal oxide 230b and the metal oxide 230c can be improved.

[0402] Here, the conductor 260 is sometimes used as a first gate (also called a top gate) electrode. In addition, the conductor 205 is sometimes used as a second gate (also called a bottom gate) electrode. In this case, the V of the transistor 200A can be controlled by independently changing the potential supplied to the conductor 205 without linking it with the potential supplied to the conductor 260. th In particular, by supplying a negative potential to the conductor 205, the V of the transistor 200A can be increased. th Therefore, when a negative potential is applied to the conductor 205 , the drain current of the transistor 200A when the potential supplied to the conductor 260 is 0 V can be reduced compared to when no negative potential is applied to the conductor 205 .

[0403] Furthermore, the conductor 205 is preferably larger than the channel formation region in the metal oxide 230. In particular, Fig.27C As shown, the conductor 205 preferably extends to the region outside the end portion intersecting the metal oxide 230 in the channel width direction. That is, the conductor 205 and the conductor 260 preferably overlap with the insulator outside the side surface of the metal oxide 230 in the channel width direction.

[0404] With the above structure, the channel formation region of the metal oxide 230 can be electrically surrounded by the electric field of the conductor 260 used as the first gate electrode and the electric field of the conductor 205 used as the second gate electrode.

[0405] In addition, if Fig.27C As shown in FIG. 1 , the conductor 205 is extended to be used as wiring. However, the present invention is not limited to this, and a conductor used as wiring may be provided under the conductor 205 .

[0406] A conductive material mainly composed of tungsten, copper, or aluminum is preferably used as the conductor 205. Note that although the conductor 205 is shown as a single layer, the conductor 205 may have a stacked structure, for example, a stacked structure of titanium, titanium nitride, and the above conductive materials.

[0407] Alternatively, a conductive layer having a function of suppressing hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules (N 2 O, NO, NO 2 It is also preferable to use a conductor having a function of inhibiting the diffusion of impurities such as copper atoms, etc. (not allowing the above impurities to pass through easily). In addition, it is preferable to use a conductor having a function of inhibiting the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.) (not allowing the above oxygen to pass through easily). In this specification, "the function of inhibiting the diffusion of impurities or oxygen" means the function of inhibiting the diffusion of any one or all of the above impurities and the above oxygen.

[0408] When a conductor having a function of suppressing the diffusion of oxygen is used under the conductor 205, it is possible to suppress the decrease in conductivity caused by oxidation of the conductor 205. As the conductor having a function of suppressing the diffusion of oxygen, for example, tantalum, tantalum nitride, ruthenium, or ruthenium oxide is preferably used. Therefore, as the first conductor of the conductor 205, a single layer or a stack of the above conductive materials can be used.

[0409] The insulator 214 is preferably used as a blocking insulating film for inhibiting impurities such as water and hydrogen from entering the transistor 200A from the substrate side. Therefore, as the insulator 214, it is preferable to use a film having a property of inhibiting hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules (N 2 O, NO, NO 2 Insulating materials having the function of inhibiting the diffusion of impurities such as copper atoms, etc. (not allowing the impurities to pass through easily). In addition, it is preferred to use insulating materials having the function of inhibiting the diffusion of at least one of oxygen (e.g., oxygen atoms, oxygen molecules, etc.) (not allowing the oxygen to pass through easily).

[0410] For example, aluminum oxide or silicon nitride is preferably used as the insulator 214. This can suppress diffusion of impurities such as water and hydrogen from the substrate side closer to the insulator 214 to the transistor 200A side. In addition, diffusion of oxygen contained in the insulator 224 or the like to the substrate side closer to the insulator 214 can be suppressed.

[0411] In addition, the dielectric constant of the insulator 216, the insulator 280, and the insulator 281 used as the interlayer film is preferably lower than that of the insulator 214. By using a material with a low dielectric constant as the interlayer film, the parasitic capacitance generated between the wirings can be reduced. For example, as the insulator 216, the insulator 280, and the insulator 281, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, or silicon oxide having pores, etc. are appropriately used.

[0412] Insulator 222 and insulator 224 are used as gate insulators.

[0413] Here, in the insulator 224 in contact with the metal oxide 230, oxygen is preferably removed by heating. In this specification, etc., oxygen removed by heating is sometimes referred to as excess oxygen. For example, silicon oxide or silicon oxynitride can be appropriately used as the insulator 224. By providing an insulator containing oxygen in contact with the metal oxide 230, oxygen vacancies in the metal oxide 230 can be reduced, thereby improving the reliability of the transistor 200A.

[0414] Specifically, an oxide material from which a part of oxygen is released by heating is preferably used as the insulator 224. The oxide from which oxygen is released by heating means that the amount of oxygen released in terms of oxygen atoms in TDS (Thermal Desorption Spectroscopy) analysis is 1.0×10 18 atoms / cm 3 Above, preferably 1.0×10 19 atoms / cm 3 More preferably, 2.0×10 19 atoms / cm 3 Above, or 3.0×10 20 atoms / cm 3 Furthermore, the surface temperature of the film when performing the above-mentioned TDS analysis is preferably in the range of 100° C. to 700° C., or 100° C. to 400° C.

[0415] In addition, if Fig.27C As shown, the thickness of the region that does not overlap with the insulator 254 and the metal oxide 230b in the insulator 224 is sometimes thinner than the thickness of other regions. In the insulator 224, the region that does not overlap with the insulator 254 and the metal oxide 230b preferably has a thickness sufficient to diffuse the oxygen.

[0416] The insulator 222 is preferably used as a blocking insulating film for suppressing impurities such as water and hydrogen from entering the transistor 200A from the substrate side, similarly to the insulator 214. For example, the hydrogen permeability of the insulator 222 is preferably lower than that of the insulator 224. By surrounding the insulator 224, the metal oxide 230, and the insulator 250 with the insulator 222, the insulator 254, and the insulator 274, impurities such as water and hydrogen can be suppressed from entering the transistor 200A from the outside.

[0417] Furthermore, the insulator 222 preferably has a function of suppressing the diffusion of at least one of oxygen (e.g., oxygen atoms, oxygen molecules, etc.) (not allowing the oxygen to pass through easily). For example, the oxygen permeability of the insulator 222 is preferably lower than that of the insulator 224. By making the insulator 222 have a function of suppressing the diffusion of oxygen or impurities, it is preferable because the diffusion of oxygen contained in the metal oxide 230 to the substrate side can be reduced. In addition, the conductor 205 can be suppressed from reacting with oxygen contained in the insulator 224 and the metal oxide 230.

[0418] The insulator 222 preferably uses an insulator containing an oxide of one or both of aluminum and hafnium as an insulating material. As the insulator containing an oxide of one or both of aluminum and hafnium, aluminum oxide and hafnium oxide are preferably used. Alternatively, an oxide containing aluminum and hafnium (hafnium aluminate) is preferably used. When the insulator 222 is formed using such a material, the insulator 222 is used as a layer that suppresses the release of oxygen from the metal oxide 230 and the entry of impurities such as hydrogen into the metal oxide 230 from the surrounding portion of the transistor 200A.

[0419] Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, or zirconium oxide may be added to the insulator. In addition, the insulator may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be stacked on the insulator.

[0420] In addition, as the insulator 222, for example, aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO 3 ) or (Ba, Sr)TiO 3 (BST) and other so-called high-k insulators. When miniaturization and high integration of transistors are carried out, problems such as leakage current may occur due to the thinning of the gate insulator. By using a high-k material as an insulator used as a gate insulator, the gate potential during transistor operation can be reduced while maintaining the physical thickness.

[0421] In addition, the insulator 222 and the insulator 224 may also have a laminated structure of two or more layers. In this case, it is not limited to a laminated structure composed of the same material, and may also be a laminated structure composed of different materials. For example, an insulator similar to the insulator 224 may be provided under the insulator 222.

[0422] The metal oxide 230 includes a metal oxide 230a, a metal oxide 230b on the metal oxide 230a, and a metal oxide 230c on the metal oxide 230b. When the metal oxide 230a is provided under the metal oxide 230b, it is possible to suppress the diffusion of impurities from the structure formed under the metal oxide 230a to the metal oxide 230b. When the metal oxide 230c is provided on the metal oxide 230b, it is possible to suppress the diffusion of impurities from the structure formed above the metal oxide 230c to the metal oxide 230b.

[0423] In addition, the metal oxide 230 preferably has a laminated structure of oxides in which the atomic number ratios of the metal atoms are different from each other. Specifically, in the metal oxide used for the metal oxide 230a, the atomic number ratio of the element M in the constituent elements is preferably greater than the atomic number ratio of the element M in the constituent elements of the metal oxide used for the metal oxide 230b. In addition, in the metal oxide used for the metal oxide 230a, the atomic number ratio of the element M to In is preferably greater than the atomic number ratio of the element M to In in the metal oxide used for the metal oxide 230b. In addition, in the metal oxide used for the metal oxide 230b, the atomic number ratio of In to the element M is preferably greater than the atomic number ratio of In to the element M in the metal oxide used for the metal oxide 230a. In addition, the metal oxide 230c can use a metal oxide that can be used for the metal oxide 230a or the metal oxide 230b.

[0424] The metal oxide 230a, the metal oxide 230b, and the metal oxide 230c are preferably crystalline, and in particular, CAAC-OS (c-axis aligned crystalline oxide semiconductor) is preferably used. Crystalline oxides such as CAAC-OS have a highly crystalline and dense structure with few impurities and defects (oxygen vacancies, etc.). Therefore, it is possible to suppress the source electrode or the drain electrode from extracting oxygen from the metal oxide 230b. Therefore, even if heat treatment is performed, the oxygen extracted from the metal oxide 230b can be reduced. Therefore, the transistor 200A is also stable to the high temperature (so-called thermal budget) in the manufacturing process.

[0425] It is preferred that the energy of the conduction band bottom of the metal oxide 230a and the metal oxide 230c is higher than the energy of the conduction band bottom of the metal oxide 230b. In other words, the electron affinity of the metal oxide 230a and the metal oxide 230c is preferably less than the electron affinity of the metal oxide 230b. In this case, the metal oxide 230c preferably uses a metal oxide that can be used for the metal oxide 230a. Specifically, in the metal oxide used for the metal oxide 230c, the atomic number ratio of the element M in the constituent elements is preferably greater than the atomic number ratio of the element M in the constituent elements of the metal oxide used for the metal oxide 230b. In addition, in the metal oxide used for the metal oxide 230c, the atomic number ratio of the element M to In is preferably greater than the atomic number ratio of the element M to In in the metal oxide used for the metal oxide 230b. In addition, in the metal oxide used for the metal oxide 230b, the atomic number ratio of In to the element M is preferably greater than the atomic number ratio of In to the element M in the metal oxide used for the metal oxide 230c.

[0426] Here, in the junction of the metal oxide 230a, the metal oxide 230b and the metal oxide 230c, the energy level of the conduction band bottom changes smoothly. In other words, the above situation can also be expressed as the energy level of the conduction band bottom of the junction of the metal oxide 230a, the metal oxide 230b and the metal oxide 230c continuously changing or continuously joining. For this reason, it is preferred to reduce the defect state density of the mixed layer formed at the interface between the metal oxide 230a and the metal oxide 230b and the interface between the metal oxide 230b and the metal oxide 230c.

[0427] Specifically, by making the metal oxide 230a and the metal oxide 230b, and the metal oxide 230b and the metal oxide 230c contain a common element (as a main component) in addition to oxygen, a mixed layer with a low defect state density can be formed. For example, in the case where the metal oxide 230b is an In-Ga-Zn oxide, In-Ga-Zn oxide, Ga-Zn oxide, and gallium oxide can be used as the metal oxide 230a and the metal oxide 230c. In addition, the metal oxide 230c can have a stacked structure. For example, a stacked structure of In-Ga-Zn oxide and Ga-Zn oxide on the In-Ga-Zn oxide can be used, or a stacked structure of In-Ga-Zn oxide and gallium oxide on the In-Ga-Zn oxide can be used. In other words, as the metal oxide 230c, a stacked structure of In-Ga-Zn oxide and an oxide that does not contain In can also be used.

[0428] Specifically, as the metal oxide 230a, a metal oxide having an atomic ratio of In:Ga:Zn=1:3:4 or 1:1:0.5 may be used. Furthermore, as the metal oxide 230b, a metal oxide having an atomic ratio of In:Ga:Zn=4:2:3 or 3:1:2 may be used. Furthermore, as the metal oxide 230c, a metal oxide having an atomic ratio of In:Ga:Zn=1:3:4, In:Ga:Zn=4:2:3, Ga:Zn=2:1 or Ga:Zn=2:5 may be used. In addition, as specific examples of the case where the metal oxide 230c has a stacked structure, there can be cited a stacked structure of In:Ga:Zn=4:2:3 [atomic ratio] and Ga:Zn=2:1 [atomic ratio], a stacked structure of In:Ga:Zn=4:2:3 [atomic ratio] and Ga:Zn=2:5 [atomic ratio], a stacked structure of In:Ga:Zn=4:2:3 [atomic ratio] and gallium oxide, and the like.

[0429] At this time, the main path of the carrier is the metal oxide 230b. By making the metal oxide 230a and the metal oxide 230c have the above structure, the defect state density of the interface between the metal oxide 230a and the metal oxide 230b and the interface between the metal oxide 230b and the metal oxide 230c can be reduced. Therefore, the influence of interface scattering on carrier conduction is reduced, so that the transistor 200A can obtain high on-state current and high frequency characteristics. In addition, when the metal oxide 230c has a stacked structure, it is expected to reduce the effect of the defect state density of the interface between the above-mentioned metal oxide 230b and the metal oxide 230c and the effect of suppressing the diffusion of the constituent elements of the metal oxide 230c to the side of the insulator 250. More specifically, because the metal oxide 230c has a stacked structure and the oxide that does not contain In is located above the stacked structure, it is possible to suppress In that will diffuse to the side of the insulator 250. Since the insulator 250 is used as a gate insulator, the characteristics of the transistor are poor when In is diffused therein. Thus, by making the metal oxide 230c have a stacked structure, a display device with high reliability can be provided.

[0430] As the metal oxide 230, a metal oxide used as an oxide semiconductor is preferably used. For example, as the metal oxide that becomes the channel formation region of the metal oxide 230, it is preferable to use a metal oxide whose band gap is 2 eV or more, preferably 2.5 eV or more. In this way, by using a metal oxide with a wider band gap, the off-state current of the transistor can be reduced. By using such a transistor, a low-power display device can be provided.

[0431] A conductor 242 (conductor 242a and conductor 242b) used as a source electrode and a drain electrode is provided on the metal oxide 230b. As the conductor 242, a metal element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium and lanthanum, an alloy containing the above metal elements as a component, or an alloy combining the above metal elements is preferably used. For example, tantalum nitride, titanium nitride, tungsten, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, an oxide containing lanthanum and nickel, etc. are preferably used. In addition, tantalum nitride, titanium nitride, nitride containing titanium and aluminum, nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxide containing strontium and ruthenium, and oxide containing lanthanum and nickel are conductive materials that are not easily oxidized or materials that maintain conductivity even when absorbing oxygen, and therefore are preferred.

[0432] By forming the above-mentioned conductor 242 in contact with the metal oxide 230, the oxygen concentration near the conductor 242 in the metal oxide 230 may be reduced. In addition, a metal compound layer including a metal contained in the conductor 242 and a component of the metal oxide 230 may be formed near the conductor 242 in the metal oxide 230. In this case, the carrier density in the region near the conductor 242 of the metal oxide 230 increases, and the resistance of the region decreases.

[0433] Here, the region between the conductor 242a and the conductor 242b is formed so as to overlap with the opening of the insulator 280. Therefore, the conductor 260 can be arranged in a self-aligned manner between the conductor 242a and the conductor 242b.

[0434] The insulator 250 is used as a gate insulator. The insulator 250 is preferably arranged in contact with the top surface of the metal oxide 230c. The insulator 250 can be made of silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, or silicon oxide with pores. In particular, silicon oxide and silicon oxynitride are preferred because they have thermal stability.

[0435] As with the insulator 224, it is preferable to reduce the concentration of impurities such as water and hydrogen in the insulator 250. The thickness of the insulator 250 is preferably not less than 1 nm and not more than 20 nm.

[0436] Furthermore, a metal oxide may be provided between the insulator 250 and the conductor 260. The metal oxide preferably suppresses oxygen from diffusing from the insulator 250 to the conductor 260. Thus, oxidation of the conductor 260 due to oxygen in the insulator 250 can be suppressed.

[0437] In addition, the metal oxide is sometimes used as a part of the gate insulator. Therefore, when silicon oxide or silicon oxynitride is used for the insulator 250, it is preferable to use a metal oxide that is a high-k material with a high relative dielectric constant as the metal oxide. By making the gate insulator have a stacked structure of the insulator 250 and the metal oxide, a transistor 200A with thermal stability and a high relative dielectric constant can be formed. Therefore, the gate potential applied when the transistor is operating can be reduced while maintaining the physical thickness of the gate insulator. In addition, the equivalent oxide thickness (EOT: Equivalent Oxide Thickness) of the insulator used as the gate insulator can be reduced.

[0438] Specifically, metal oxides containing one or more metals selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, and magnesium can be used. In particular, aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate), which is an insulator containing one or both oxides of aluminum and hafnium, is preferably used.

[0439] Although the conductor 260 has a two-layer structure in FIG. 27 , it may have a single-layer structure or a stacked-layer structure of three or more layers.

[0440] As the conductor 260a, it is preferable to use the above-mentioned conductor having the function of inhibiting hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N 2 O, NO, NO 2 In addition, it is preferable to use a conductive material having a function of inhibiting the diffusion of at least one of oxygen (for example, oxygen atoms, oxygen molecules, etc.).

[0441] In addition, when the conductor 260a has a function of suppressing the diffusion of oxygen, it is possible to suppress the decrease in the conductivity of the conductor 260b caused by oxidation of the conductor 260b by the oxygen contained in the insulator 250. As a conductive material having a function of suppressing the diffusion of oxygen, for example, tantalum, tantalum nitride, ruthenium, or ruthenium oxide is preferably used.

[0442] In addition, as the conductor 260b, it is preferable to use a conductive material with tungsten, copper or aluminum as a main component. In addition, since the conductor 260 is also used as wiring, it is preferable to use a conductor with high conductivity. For example, a conductive material with tungsten, copper or aluminum as a main component can be used. In addition, the conductor 260b can have a laminated structure, for example, it can have a laminated structure of titanium, titanium nitride and the above conductive materials.

[0443] In addition, if Fig.27A and Fig.27C As shown, in the region of the metal oxide 230b that does not overlap with the conductor 242, that is, in the channel formation region of the metal oxide 230, the side surface of the metal oxide 230 is covered by the conductor 260. Thus, the electric field of the conductor 260 used as the first gate electrode can be easily affected on the side surface of the metal oxide 230. Thus, the on-state current and frequency characteristics of the transistor 200A can be improved.

[0444] The insulator 254 is preferably used as a blocking insulating film for suppressing impurities such as water and hydrogen from entering the transistor 200A from the insulator 280 side, similarly to the insulator 214. For example, the hydrogen permeability of the insulator 254 is preferably lower than that of the insulator 224. Fig.27B , Fig.27CAs shown, the insulator 254 is preferably in contact with the side surface of the metal oxide 230c, the top surface and side surface of the conductor 242a, the top surface and side surface of the conductor 242b, the side surface of the metal oxide 230a, the side surface of the metal oxide 230b, and the top surface of the insulator 224. By adopting such a structure, hydrogen contained in the insulator 280 can be suppressed from entering the metal oxide 230 from the top surface or side surface of the conductor 242a, the conductor 242b, the metal oxide 230a, the metal oxide 230b, and the insulator 224.

[0445] Furthermore, the insulator 254 has a function of inhibiting diffusion of at least one of oxygen (eg, oxygen atoms, oxygen molecules, etc.) (ie, preventing the oxygen from penetrating). For example, the oxygen permeability of the insulator 254 is preferably lower than that of the insulator 280 or the insulator 224 .

[0446] The insulator 254 is preferably formed by a sputtering method. By forming the insulator 254 by a sputtering method in an atmosphere containing oxygen, oxygen can be added to the vicinity of the region where the insulator 224 contacts the insulator 254. Thus, oxygen can be supplied from the region to the metal oxide 230 through the insulator 224. Here, by making the insulator 254 have a function of suppressing oxygen diffusion to the upper side, oxygen can be prevented from diffusing from the metal oxide 230 to the insulator 280. In addition, by making the insulator 222 have a function of suppressing oxygen diffusion to the lower side, oxygen can be prevented from diffusing from the metal oxide 230 to the substrate side. In this way, oxygen is supplied to the channel formation region in the metal oxide 230. Thus, oxygen vacancies in the metal oxide 230 can be reduced and the normally-on state of the transistor can be suppressed.

[0447] For example, an insulator including an oxide of one or both of aluminum and hafnium can be formed as the insulator 254. Note that as the insulator including an oxide of one or both of aluminum and hafnium, aluminum oxide, hafnium oxide, an oxide including aluminum and hafnium (hafnium aluminate), or the like is preferably used.

[0448] By covering the insulator 224, the insulator 250, and the metal oxide 230 with the insulator 254 having a barrier property against hydrogen, the insulator 280 is separated from the insulator 224, the metal oxide 230, and the insulator 250 by the insulator 254. Thus, entry of impurities such as hydrogen from the outside of the transistor 200A can be suppressed, thereby providing the transistor 200A with good electrical characteristics and reliability.

[0449] The insulator 280 is preferably provided on the insulator 224, the metal oxide 230, and the conductor 242 via the insulator 254. For example, as the insulator 280, it is preferable to have silicon oxide, silicon oxynitride, silicon nitride oxide, silicon oxide to which fluorine is added, silicon oxide to which carbon is added, silicon oxide to which carbon and nitrogen are added, or silicon oxide having pores. In particular, silicon oxide and silicon oxynitride are preferred because they have thermal stability. In particular, materials such as silicon oxide, silicon oxynitride, and silicon oxide having pores are preferred because they easily form a region containing oxygen that is released by heating.

[0450] It is preferable that the concentration of impurities such as water and hydrogen is reduced in the insulator 280. In addition, the top surface of the insulator 280 may be planarized.

[0451] The insulator 274 is preferably used as a barrier insulating film for suppressing the intrusion of impurities such as water and hydrogen into the insulator 280 from above, similarly to the insulator 214. For example, the insulator 274 can be any insulator that can be used for the insulator 214 or the insulator 254.

[0452] In addition, an insulator 281 used as an interlayer film is preferably provided on the insulator 274. As with the insulator 224 and the like, the concentration of impurities such as water and hydrogen in the insulator 281 is preferably reduced.

[0453] In addition, the conductors 240a and 240b are arranged in the openings formed in the insulators 281, 274, 280, and 254. The conductors 240a and 240b are provided so as to sandwich the conductor 260. In addition, the height of the top surface of the conductors 240a and 240b and the top surface of the insulator 281 may be located on the same plane.

[0454] In addition, insulator 241a is provided in contact with the inner wall of the opening of insulator 281, insulator 274, insulator 280, and insulator 254, and the first conductor of conductor 240a is formed in contact with the side thereof. Conductor 242a is located at least a portion of the bottom of the opening, and conductor 240a is in contact with conductor 242a. Similarly, insulator 241b is provided in contact with the inner wall of the opening of insulator 281, insulator 274, insulator 280, and insulator 254, and the first conductor of conductor 240b is formed in contact with the side thereof. Conductor 242b is located at least a portion of the bottom of the opening, and conductor 240b is in contact with conductor 242b.

[0455] The conductors 240a and 240b are preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. The conductors 240a and 240b may have a stacked structure.

[0456] When a laminated structure is used as the conductor 240, the conductor having the function of inhibiting the diffusion of impurities such as water or hydrogen is preferably used as the conductor in contact with the metal oxide 230a, the metal oxide 230b, the conductor 242, the insulator 254, the insulator 280, the insulator 274 and the insulator 281. For example, tantalum, tantalum nitride, titanium, titanium nitride, ruthenium or ruthenium oxide is preferably used. A conductive material having the function of inhibiting the diffusion of impurities such as water or hydrogen can be used in a single layer or a laminated layer. By using this conductive material, it is possible to prevent oxygen added to the insulator 280 from being absorbed by the conductor 240a and the conductor 240b. In addition, it is possible to prevent impurities such as water or hydrogen from being mixed into the metal oxide 230 through the conductor 240a and the conductor 240b from the layer above the insulator 281.

[0457] As the insulator 241a and the insulator 241b, for example, an insulator that can be used for the insulator 254 or the like may be used. Since the insulator 241a and the insulator 241b are provided in contact with the insulator 254, it is possible to suppress impurities such as water or hydrogen from the insulator 280 from entering the metal oxide 230 through the conductors 240a and 240b. In addition, it is possible to prevent oxygen contained in the insulator 280 from being absorbed by the conductors 240a and 240b.

[0458] Although not shown, the conductor used as wiring can be arranged in a manner of contacting the top surface of the conductor 240a and the top surface of the conductor 240b. The conductor used as wiring preferably uses a conductive material with tungsten, copper or aluminum as a main component. In addition, the conductor can have a laminated structure, for example, a laminated structure of titanium, titanium nitride and the above conductive materials. In addition, the conductor can also be formed in a manner of being embedded in the opening of the insulator.

[0459] <Structural Example 2 of Transistor>

[0460] Fig.28A , Fig.28B and Fig.28C 1 and 2 are a plan view and a cross-sectional view of a transistor 200B and its surroundings that can be used in a display device according to one embodiment of the present invention. The transistor 200B is a modified example of the transistor 200A.

[0461] Fig.28A is a top view of transistor 200B. In addition, Fig.28B and Fig.28C is a cross-sectional view of transistor 200B. Here, Fig.28B It is along Fig.28A The cross-sectional view taken along the dotted line B1-B2 in FIG. 1 is equivalent to a cross-sectional view of the transistor 200B in the channel length direction. Fig.28C It is along Fig.28AThe cross-sectional view along the dotted line B3-B4 in FIG. 1 is equivalent to the cross-sectional view along the channel width direction of the transistor 200B. Note that for ease of understanding, Fig.28A Some components are omitted in the top view.

[0462] In the transistor 200B, the conductors 242a and 242b have regions overlapping with the metal oxide 230c, the insulator 250, and the conductor 260. Thus, the transistor 200B can be a transistor with a high on-state current. In addition, the transistor 200B can be a transistor that is easily controlled.

[0463] The conductor 260 used as the gate electrode includes a conductor 260a and a conductor 260b on the conductor 260a. The conductor 260a is preferably made of a conductive material having a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms. In addition, it is preferable to use a conductive material having a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms and oxygen molecules).

[0464] By providing the conductor 260a with a function of suppressing oxygen diffusion, the material selectivity of the conductor 260b can be improved. That is, by including the conductor 260a, oxidation of the conductor 260b can be suppressed, thereby suppressing a decrease in conductivity.

[0465] Insulator 254 is preferably provided to cover the top and side surfaces of conductor 260, the side surfaces of insulator 250, and the side surfaces of metal oxide 230c. Insulator 254 is preferably made of an insulating material having a function of suppressing diffusion of impurities such as water and hydrogen and oxygen.

[0466] The insulator 254 can be provided to suppress oxidation of the conductor 260. In addition, the insulator 254 can be provided to suppress diffusion of impurities such as water and hydrogen contained in the insulator 280 into the transistor 200B.

[0467] <Structural Example 3 of Transistor>

[0468] Fig.29A , Fig.29B and Fig.29C 1 and 2 are a plan view and a cross-sectional view of a transistor 200C and its surroundings that can be used in a display device according to one embodiment of the present invention. The transistor 200C is a modified example of the transistor 200A.

[0469] Fig.29A is a top view of transistor 200C. In addition, Fig.29B and Fig.29C is a cross-sectional view of transistor 200C. Here, Fig.29B It is along Fig.29AThe cross-sectional view taken along the dotted line C1-C2 in FIG. 1 is equivalent to a cross-sectional view of the transistor 200C in the channel length direction. Fig.29C It is along Fig.29A The cross-sectional view along the dotted line C3-C4 in FIG. 1 is equivalent to the cross-sectional view along the channel width direction of the transistor 200C. Note that for ease of understanding, Fig.29A Some components are omitted in the top view.

[0470] In the transistor 200C, an insulator 250 is included on the metal oxide 230c, and a metal oxide 252 is included on the insulator 250. In addition, a conductor 260 is included on the metal oxide 252, and an insulator 270 is included on the conductor 260. In addition, an insulator 271 is included on the insulator 270.

[0471] The metal oxide 252 preferably has a function of suppressing oxygen diffusion. By providing the metal oxide 252 that suppresses oxygen diffusion between the insulator 250 and the conductor 260, oxygen diffusion to the conductor 260 is suppressed. In other words, the reduction in the amount of oxygen supplied to the metal oxide 230 can be suppressed. In addition, oxidation of the conductor 260 can be suppressed.

[0472] In addition, the metal oxide 252 can be used as a part of the gate electrode. For example, an oxide semiconductor that can be used as the metal oxide 230 can be used as the metal oxide 252. In this case, by forming the conductor 260 by sputtering, the resistance value of the metal oxide 252 can be reduced to make it a conductor. This can be called an OC (Oxide Conductor) electrode.

[0473] In addition, the metal oxide 252 is sometimes used as a part of the gate insulator. Therefore, when silicon oxide or silicon oxynitride, which is a material with high thermal stability, is used for the insulator 250, it is preferable to use a metal oxide, which is a high-k material with a high relative dielectric constant, as the metal oxide 252. By adopting this stacked structure, a transistor 200C with thermal stability and a high relative dielectric constant can be formed. Therefore, the gate potential applied when the transistor is operating can be reduced while maintaining the physical thickness. In addition, the equivalent oxide thickness (EOT) of the insulating layer used as the gate insulator can be reduced.

[0474] Although the metal oxide 252 in the transistor 200C is shown as a single-layer structure, a stacked structure of two or more layers may be adopted. For example, a metal oxide used as a part of the gate electrode and a metal oxide used as a part of the gate insulator may be stacked.

[0475] When the transistor 200C has the metal oxide 252 and uses the metal oxide 252 as a gate electrode, the on-state current of the transistor 200C can be increased without weakening the influence of the electric field from the conductor 260. In addition, when the metal oxide 252 is used as a gate insulator, the distance between the conductor 260 and the metal oxide 230 can be maintained by utilizing the physical thickness of the insulator 250 and the metal oxide 252. Thus, the leakage current between the conductor 260 and the metal oxide 230 can be suppressed. Thus, by making the transistor 200C have a stacked structure of the insulator 250 and the metal oxide 252, the physical distance between the conductor 260 and the metal oxide 230 and the electric field strength applied from the conductor 260 to the metal oxide 230 can be easily adjusted.

[0476] Specifically, an oxide semiconductor that can be used for the metal oxide 230 can be used as the metal oxide 252 by reducing its resistance. Alternatively, a metal oxide containing one or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, and magnesium can be used.

[0477] In particular, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), etc. are preferably used as an insulating layer containing an oxide of one or both of aluminum and hafnium. In particular, hafnium aluminate has higher heat resistance than hafnium oxide film. Therefore, it is not easy to crystallize in the heat treatment of the subsequent process, so it is preferred. Note that the metal oxide 252 is not an essential component and can be appropriately designed according to the desired transistor characteristics.

[0478] An insulating material having a function of inhibiting the permeation of impurities such as water or hydrogen and oxygen is preferably used as the insulator 270. For example, aluminum oxide or hafnium oxide is preferably used. Thus, the conductor 260 can be prevented from being oxidized by oxygen from above the insulator 270. In addition, impurities such as water or hydrogen from above the insulator 270 can be inhibited from entering the metal oxide 230 through the conductor 260 and the insulator 250.

[0479] Insulator 271 is used as a hard mask. By providing insulator 271, when processing conductor 260, the side surface of conductor 260 can be made substantially vertical, specifically, the angle formed by the side surface of conductor 260 and the substrate surface can be made greater than 75 degrees and less than 100 degrees, preferably greater than 80 degrees and less than 95 degrees.

[0480] Alternatively, the insulator 271 may also function as a barrier layer by using an insulating material having a function of suppressing the permeation of impurities such as water and hydrogen and oxygen as the insulator 271. In this case, the insulator 270 may not be provided.

[0481] By using the insulator 271 as a hard mask, the insulator 270, the conductor 260, the metal oxide 252, the insulator 250, and a portion of the metal oxide 230c are selectively removed, so that their side surfaces can be roughly aligned and a portion of the surface of the metal oxide 230b can be exposed.

[0482] In addition, the transistor 200C has a region 243a and a region 243b in a portion of the surface of the exposed metal oxide 230b. One of the region 243a and the region 243b is used as a source region, and the other is used as a drain region.

[0483] For example, the regions 243a and 243b can be formed by introducing an impurity element such as phosphorus or boron into the surface of the exposed metal oxide 230b by ion implantation, ion doping, plasma immersion ion implantation, plasma treatment, etc. Note that in this embodiment, "impurity element" refers to an element other than a main component element.

[0484] Alternatively, after a portion of the surface of the metal oxide 230 b is exposed, a metal film may be formed, and then heat treatment may be performed to diffuse elements included in the metal film into the metal oxide 230 b , thereby forming the regions 243 a and 243 b .

[0485] The resistivity of the region into which the impurity element is introduced in the metal oxide 230b decreases. Therefore, the region 243a and the region 243b are sometimes referred to as “impurity regions” or “low resistance regions”.

[0486] By using the insulator 271 and / or the conductor 260 as a mask, the region 243a and the region 243b can be formed in a self-aligned manner. Therefore, the region 243a and / or the region 243b do not overlap with the conductor 260, and the parasitic capacitance can be reduced. In addition, the bias region is not formed between the channel formation region and the source and drain region (region 243a or region 243b). By forming the region 243a and the region 243b in a self-aligned manner, an increase in on-state current, a decrease in threshold voltage, an increase in operating frequency, etc. can be achieved.

[0487] The transistor 200C includes an insulator 272 on the side of the insulator 271, the insulator 270, the conductor 260, the metal oxide 252, the insulator 250, and the metal oxide 230c. The insulator 272 is preferably an insulator with a low relative dielectric constant. For example, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, silicon oxide with pores, or resin is preferably used. In particular, when silicon oxide, silicon oxynitride, silicon nitride oxide, or silicon oxide with pores is used for the insulator 272, it is preferred because an excess oxygen region can be easily formed in the insulator 272 in the subsequent process. In addition, silicon oxide and silicon oxynitride have thermal stability, so they are preferred. In addition, the insulator 272 preferably has a function of diffusing oxygen.

[0488] In addition, in order to further reduce the off-state current, a bias region may be provided between the channel formation region and the source / drain region. The bias region is a region with high resistivity and is a region where the above-mentioned impurity element is not introduced. The bias region can be formed by introducing the above-mentioned impurity element after forming the insulator 272. In this case, the insulator 272 is also used as a mask as the insulator 271. Therefore, the region of the metal oxide 230b overlapping with the insulator 272 is not introduced with the impurity element, thereby maintaining the resistivity of the region high.

[0489] Furthermore, the transistor 200C includes an insulator 254 on the insulator 272 and the metal oxide 230. The insulator 254 is preferably formed by sputtering. By using the sputtering method, an insulator with less impurities such as water and hydrogen can be formed.

[0490] Sometimes, an oxide film formed by sputtering extracts hydrogen from the formed structure. Therefore, when the insulator 254 is formed by sputtering, the insulator 254 extracts hydrogen and water from the metal oxide 230 and the insulator 272. Thus, the hydrogen concentration of the metal oxide 230 and the insulator 272 can be reduced.

[0491] <Materials Constituting Transistors>

[0492] Hereinafter, constituent materials that can be used for the transistor will be described.

[0493] Substrate

[0494] As a substrate for forming the transistor 200, for example, an insulator substrate, a semiconductor substrate, or a conductor substrate can be used. As an insulator substrate, for example, a glass substrate, a quartz substrate, a sapphire substrate, a stabilized zirconia substrate (yttria stabilized zirconia substrate, etc.), a resin substrate, etc. can be cited. In addition, as a semiconductor substrate, for example, a semiconductor substrate composed of silicon or germanium, or a compound semiconductor substrate composed of silicon carbide, silicon germanium, gallium arsenide, indium phosphide, zinc oxide, or gallium oxide can be cited. Furthermore, a semiconductor substrate having an insulator region inside the above-mentioned semiconductor substrate can also be cited, such as an SOI (Silicon On Insulator) substrate, etc. As a conductor substrate, a graphite substrate, a metal substrate, an alloy substrate, a conductive resin substrate, etc. can be cited. Alternatively, a substrate containing a metal nitride, a substrate containing a metal oxide, etc. can be cited. Furthermore, an insulator substrate provided with a conductor or a semiconductor, a semiconductor substrate provided with a conductor or an insulator, a conductor substrate provided with a semiconductor or an insulator, etc. can also be cited. Alternatively, a substrate having an element provided on these substrates can also be used. Examples of the element provided over the substrate include a capacitor, a resistor, a switching element, and a memory element.

[0495] Insulator

[0496] Examples of the insulator include oxides, nitrides, oxynitrides, oxynitrides, metal oxides, metal oxynitrides, and metal oxynitrides having insulating properties.

[0497] For example, when miniaturization and high integration of transistors are being carried out, problems such as leakage current may occur due to the thin filming of the gate insulator. By using a high-k material as an insulator used as a gate insulator, it is possible to achieve low voltage when the transistor is operating while maintaining the physical thickness. On the other hand, by using a material with a low relative dielectric constant for an insulator used as an interlayer film, it is possible to reduce the parasitic capacitance generated between wirings. Therefore, it is preferable to select a material according to the function of the insulator.

[0498] In addition, as insulators with a relatively high dielectric constant, gallium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium, oxynitrides containing aluminum and hafnium, oxides containing silicon and hafnium, oxynitrides containing silicon and hafnium, or nitrides containing silicon and hafnium can be cited.

[0499] Insulators having a relatively low dielectric constant include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, silicon oxide having pores, and resins.

[0500] In addition, by surrounding a transistor using an oxide semiconductor with an insulator having a function of suppressing the permeation of impurities such as hydrogen and oxygen (insulator 214, insulator 222, insulator 254, insulator 274, etc.), the electrical characteristics of the transistor can be stabilized. As an insulator having a function of suppressing the permeation of impurities such as hydrogen and oxygen, for example, an insulator containing boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum, neodymium, hafnium or tantalum can be used in a single layer or a stacked layer. Specifically, as an insulator having a function of suppressing the permeation of impurities such as hydrogen and oxygen, metal oxides such as aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide or tantalum oxide, and metal nitrides such as aluminum nitride, aluminum titanium nitride, titanium nitride, silicon oxynitride or silicon nitride can be used.

[0501] In addition, the insulator used as the gate insulator is preferably an insulator having a region containing oxygen that is released by heating. For example, by adopting a structure in which silicon oxide or silicon oxynitride having a region containing oxygen that is released by heating is in contact with the metal oxide 230, oxygen vacancies contained in the metal oxide 230 can be filled.

[0502] Conductors

[0503] As the conductor, it is preferred to use a metal element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium and lanthanum, an alloy containing the above metal elements as a component, or an alloy combining the above metal elements, etc. For example, it is preferred to use tantalum nitride, titanium nitride, tungsten, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, an oxide containing lanthanum and nickel, etc. In addition, tantalum nitride, titanium nitride, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, and an oxide containing lanthanum and nickel are conductive materials that are not easily oxidized or materials that maintain conductivity even when absorbing oxygen, so they are preferred. Alternatively, a semiconductor having high conductivity, such as polycrystalline silicon containing an impurity element such as phosphorus, or silicide such as nickel silicide may be used.

[0504] In addition, a plurality of conductors formed of the above-mentioned materials may be stacked. For example, a laminated structure in which a material containing the above-mentioned metal element and a conductive material containing oxygen are combined may be used. In addition, a laminated structure in which a material containing the above-mentioned metal element and a conductive material containing nitrogen are combined may be used. In addition, a laminated structure in which a material containing the above-mentioned metal element, a conductive material containing oxygen, and a conductive material containing nitrogen are combined may be used.

[0505] In addition, when a metal oxide is used in the channel formation region of a transistor, a laminated structure of a material containing the above-mentioned metal element and a conductive material containing oxygen is preferably used as a conductor used as a gate electrode. In this case, the conductive material containing oxygen is preferably arranged on one side of the channel formation region. By arranging the conductive material containing oxygen on one side of the channel formation region, oxygen separated from the conductive material is easily supplied to the channel formation region.

[0506] In particular, as a conductor used as a gate electrode, it is preferable to use a conductive material containing a metal element and oxygen contained in a metal oxide forming a channel. In addition, a conductive material containing the above-mentioned metal element and nitrogen can also be used. For example, a conductive material containing nitrogen such as titanium nitride and tantalum nitride can also be used. In addition, indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, and indium tin oxide added with silicon can be used. In addition, indium gallium zinc oxide containing nitrogen can also be used. By using the above-mentioned materials, hydrogen contained in the metal oxide forming the channel can sometimes be captured. Alternatively, hydrogen entering from an external insulator can sometimes be captured.

[0507] 《Metal Oxides》

[0508] The metal oxide preferably contains at least indium or zinc. In particular, it preferably contains indium and zinc. In addition, it preferably contains aluminum, gallium, yttrium or tin. Alternatively, it may contain one or more of boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten and magnesium.

[0509] Here, the case where the metal oxide is an In-M-Zn oxide containing indium, element M and zinc is considered. Note that element M is aluminum, gallium, yttrium or tin, etc. Other elements that can be used as element M include boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc. Note that as element M, a plurality of the above elements may be combined.

[0510] Note that in this specification and the like, a metal oxide containing nitrogen may also be referred to as a metal oxide. Alternatively, a metal oxide containing nitrogen may also be referred to as a metal oxynitride.

[0511] [Structure of Metal Oxide]

[0512] Oxide semiconductors (metal oxides) are classified into single crystal oxide semiconductors and non-single crystal oxide semiconductors. Examples of non-single crystal oxide semiconductors include CAAC-OS, polycrystalline oxide semiconductors, nc-OS (nanocrystalline oxide semiconductor), a-like OS (amorphous-like oxide semiconductor), and amorphous oxide semiconductors.

[0513] [Impurities]

[0514] The influence of each impurity in the metal oxide is described. When the metal oxide contains an alkali metal or an alkaline earth metal, a defect state is sometimes formed to form a carrier. Therefore, a transistor using a metal oxide containing an alkali metal or an alkaline earth metal as a channel formation region tends to have a normally-on characteristic. Therefore, it is preferred to reduce the concentration of the alkali metal or alkaline earth metal in the metal oxide. Specifically, the concentration of the alkali metal or alkaline earth metal in the metal oxide measured by secondary ion mass spectrometry (SIMS) is 1×10 18 atoms / cm 3 Below, preferably 2×10 16 atoms / cm 3 the following.

[0515] The hydrogen contained in the metal oxide reacts with the oxygen bonded to the metal atom to generate water. Therefore, the hydrogen contained in the metal oxide sometimes causes the formation of oxygen vacancies in the metal oxide. When hydrogen enters the oxygen vacancies, electrons as carriers are sometimes generated. In addition, sometimes electrons as carriers are generated due to the bonding of a part of the hydrogen with the oxygen bonded to the metal atom. Therefore, a transistor using a metal oxide containing hydrogen tends to have a normally-on characteristic.

[0516] Therefore, it is preferable to reduce the hydrogen in the metal oxide as much as possible. Specifically, the hydrogen concentration in the metal oxide measured by SIMS analysis is set to less than 1×10 20 atoms / cm 3 , preferably less than 1×10 19 atoms / cm 3 , more preferably less than 5×10 18 atoms / cm 3 , and more preferably less than 1×10 18 atoms / cm 3 By using a metal oxide in which impurities are sufficiently reduced for a channel formation region of a transistor, the transistor can have stable electrical characteristics.

[0517] As a metal oxide for a semiconductor of a transistor, a thin film with high crystallinity is preferably used. By using this thin film, the stability or reliability of the transistor can be improved. As the thin film, for example, a single crystal metal oxide thin film or a polycrystalline metal oxide thin film can be cited. However, in order to form a single crystal metal oxide thin film or a polycrystalline metal oxide thin film on a substrate, a high temperature or laser heating process is required. Therefore, the cost of the manufacturing process becomes high and the throughput decreases.

[0518] At least a part of the structural examples described in this embodiment mode and the drawings and the like corresponding to these examples can be implemented in combination with other structural examples or drawings and the like as appropriate.

[0519] At least a part of this embodiment mode can be implemented in combination with other embodiment modes described in this specification as appropriate.

[0520] (Implementation 3)

[0521] In this embodiment, an electronic device including a display device according to one embodiment of the present invention is described.

[0522] Fig. 30A FIG. 8 is an external view of a camera 8000 equipped with a viewfinder 8100. The camera 8000 is provided with an imaging device. The camera 8000 may be, for example, a digital camera. Fig. 30A In the embodiment, the camera 8000 and the viewfinder 8100 are separate and detachable electronic devices, but a viewfinder having a display device may be built into the housing 8001 of the camera 8000.

[0523] The camera 8000 includes a housing 8001 , a display portion 8002 , operation buttons 8003 , a shutter button 8004 , etc. In addition, the camera 8000 is equipped with a detachable lens 8006 .

[0524] Here, the camera 8000 has a structure in which the lens 8006 can be removed from the housing 8001 and replaced, but the lens 8006 and the housing 8001 may be formed integrally.

[0525] The camera 8000 can perform imaging by pressing a shutter button 8004. In addition, the display portion 8002 is used as a touch screen, and imaging can also be performed by touching the display portion 8002.

[0526] The housing 8001 of the camera 8000 includes an embedder having electrodes, and can be connected to a flash device or the like in addition to the viewfinder 8100 .

[0527] The viewfinder 8100 includes a housing 8101, a display portion 8102, a button 8103, etc. The viewfinder 8100 may be an electronic viewfinder.

[0528] The housing 8101 includes an inserter that is fitted into the inserter of the camera 8000, and the viewfinder 8100 can be mounted on the camera 8000. In addition, the inserter includes electrodes, and an image or the like received from the camera 8000 by the electrodes can be displayed on the display portion 8102.

[0529] The button 8103 is used as a power button. By using the button 8103, display or non-display of the display portion 8102 can be switched.

[0530] The display device of one embodiment of the present invention can be used for the display unit 8002 of the camera 8000 and the display unit 8102 of the viewfinder 8100. The display device of one embodiment of the present invention has extremely high definition, and thus, even if the display unit 8002 or the display unit 8102 is close to the user, a more realistic image can be displayed on the display unit 8002 or the display unit 8102 without the user confirming the pixels. In particular, since the user's eyes are close to the eyepiece part of the viewfinder 8100 to confirm the image displayed on the display unit 8102 of the viewfinder 8100, the distance between the user and the display unit 8102 is very close. Therefore, it is particularly preferable to use the display device of one embodiment of the present invention for the display unit 8102. In addition, when the display unit 8102 uses the display device of one embodiment of the present invention, the resolution of the image that can be displayed on the display unit 8102 can be 4K, 5K or higher.

[0531] Furthermore, the resolution of an image that can be captured by the image pickup device provided in the camera 8000 is preferably equal to or higher than the resolution of an image that can be displayed by the display unit 8002 or the display unit 8102. For example, in the case where the display unit 8102 can display an image with a resolution of 4K, it is preferable to provide an image pickup device that can capture images of 4K or higher in the camera 8000. Furthermore, in the case where the display unit 8102 can display an image with a resolution of 5K, it is preferable to provide an image pickup device that can capture images of 5K or higher in the camera 8000.

[0532] Fig. 30B This is an appearance diagram of the head mounted display 8200.

[0533] The head mounted display 8200 includes a mounting portion 8201 , a lens 8202 , a main body 8203 , a display portion 8204 , a cable 8205 , etc. In addition, a battery 8206 is built in the mounting portion 8201 .

[0534] Power is supplied from a battery 8206 to a main body 8203 via a cable 8205. The main body 8203 is provided with a wireless receiver and the like, and can display an image corresponding to received image data and the like on a display portion 8204. In addition, by capturing the movement of the user's eyeballs and eyelids with a camera provided in the main body 8203 and calculating the coordinates of the user's line of sight based on the data, the user's line of sight can be used as an input method.

[0535] In addition, a plurality of electrodes may be provided at the position of the mounting portion 8201 that is touched by the user. The main body 8203 may also have a function of recognizing the user's line of sight by detecting the current flowing through the electrodes according to the movement of the user's eyeballs. In addition, the main body 8203 may have a function of monitoring the user's pulse by detecting the current flowing through the electrodes. The mounting portion 8201 may have various sensors such as a temperature sensor, a pressure sensor, and an acceleration sensor, and may also have a function of displaying the user's biological data on the display portion 8204. In addition, the main body 8203 may also detect the movement of the user's head, etc., and change the image displayed on the display portion 8204 in synchronization with the movement of the user's head, etc.

[0536] The display device of one embodiment of the present invention can be used for the display portion 8204. Thus, the frame of the head mounted display 8200 can be narrowed, and the display portion 8204 can display high-quality images and images with a sense of reality.

[0537] Fig. 30C , Fig.30D and Fig.30E 8300 is an external view of a head mounted display 8300. The head mounted display 8300 includes a housing 8301, a display portion 8302, a belt-shaped fixing tool 8304, and a pair of lenses 8305.

[0538] The user can see the display on the display unit 8302 through the lens 8305. Preferably, the display unit 8302 is arranged in a curved manner. By arranging the display unit 8302 in a curved manner, the user can experience a high sense of presence. Note that in this embodiment, a structure in which one display unit 8302 is provided is exemplified, but the present invention is not limited thereto. For example, a structure in which two display units 8302 are provided may also be adopted. In this case, when each display unit is arranged on one side of each eye of the user, a three-dimensional display using parallax or the like can be performed.

[0539] A display device according to one embodiment of the present invention can be used for the display portion 8302. Since a display device according to one embodiment of the present invention has extremely high resolution, even if Fig.30E By using lens 8305 to enlarge in this way, it is possible to display an image with a higher sense of presence without causing the user to see the pixels.

[0540] then, FIG. 31A to FIG. 31G Shown with FIG. 30A to FIG. 30E The electronic devices shown are examples of different electronic devices.

[0541] FIG. 31A to FIG. 31G The electronic device shown includes a housing 9000, a display portion 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connecting terminal 9006, a sensor 9007 (the sensor has the function of measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared), a microphone 9008, etc.

[0542] FIG. 31A to FIG. 31G The electronic device shown has various functions. For example, it may have the following functions: the function of displaying various information (static images, dynamic images, text images, etc.) on the display unit; the function of a touch panel; the function of displaying a calendar, date, or time, etc.; the function of controlling processing by using various software (programs); the function of wireless communication; the function of connecting to various computer networks by using the wireless communication function; the function of sending or receiving various data by using the wireless communication function; the function of reading programs or data stored in a storage medium and displaying them on the display unit; etc. Note that FIG. 31A to FIG. 31G The functions that the electronic device shown may have are not limited to the above functions, but may have various functions. FIG. 31A to FIG. 31G Although not shown in the figure, the electronic device may include a plurality of display units. In addition, a camera or the like may be provided in the electronic device so as to have the following functions: a function of taking a still image; a function of taking a moving image; a function of storing the taken image in a storage medium (an external storage medium or a storage medium built into the camera); a function of displaying the taken image on the display unit; etc.

[0543] Below, we explain in detail FIG. 31A to FIG. 31G Electronic equipment shown.

[0544] Fig.31A 1 is a perspective view showing a television set 9100. The television set 9100 can be incorporated with a large display portion 9001 having a size of, for example, 50 inches or more or 100 inches or more.

[0545] The display device of one embodiment of the present invention can be used for the display portion 9001 of the television set 9100. Thus, the frame of the television set 9100 can be narrowed, and the display portion 9001 can display high-quality images and images with a sense of reality.

[0546] Fig.31B 9101 is a stereoscopic diagram showing a portable information terminal 9101. The portable information terminal 9101 has one or more functions of, for example, a telephone, an electronic notebook, and an information reading device. Specifically, it can be used as a smart phone. The portable information terminal 9101 can also be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, etc. In addition, the portable information terminal 9101 can display text or image information on its multiple faces. For example, three operation buttons 9050 (also referred to as operation icons or simply icons) can be displayed on one face of the display unit 9001. In addition, information 9051 represented by a dotted rectangle can be displayed on another face of the display unit 9001. In addition, as an example of information 9051, a display prompting the receipt of information from an email, SNS (Social Networking Services) or a phone call, etc.; a title of an email or SNS, etc.; a sender name of an email or SNS, etc.; a date; a time; a battery remaining amount; and a display of antenna reception strength, etc. can be cited. Alternatively, an operation button 9050 or the like may be displayed in place of information 9051 at a position where information 9051 is displayed.

[0547] The display device of one embodiment of the present invention can be used for the display portion 9001 of the portable information terminal 9101. Thus, the frame of the portable information terminal 9101 can be narrowed, and the display portion 9001 can display high-quality images and images with a sense of reality.

[0548] Fig.31C is a stereoscopic diagram showing a portable information terminal 9102. The portable information terminal 9102 has a function of displaying information on three or more surfaces of the display unit 9001. Here, an example is shown where information 9052, information 9053, and information 9054 are displayed on different surfaces, respectively. For example, a user of the portable information terminal 9102 can confirm its display (here, information 9053) while placing the portable information terminal 9102 in a jacket pocket. Specifically, the phone number or name of the person calling is displayed at a position where such information can be viewed from above the portable information terminal 9102. The user can confirm the display without taking the portable information terminal 9102 out of his pocket, thereby being able to determine whether to answer the call.

[0549] The display device of one embodiment of the present invention can be used for the display portion 9001 included in the portable information terminal 9102. Thus, the portable information terminal 9101 can be miniaturized, and the display portion 9001 can display high-quality images and images with a sense of reality.

[0550] Fig.31D: is a stereoscopic diagram showing a watch-type portable information terminal 9200. The portable information terminal 9200 can execute various applications such as mobile phones, e-mails, reading and editing of articles, music playback, network communications, computer games, etc. In addition, the display surface of the display unit 9001 is curved, and display can be performed on the curved display surface. In addition, the portable information terminal 9200 can perform short-range wireless communications that are standardized by communication. For example, by communicating with a headset that can perform wireless communication, a hands-free call can be made. In addition, the portable information terminal 9200 includes a connection terminal 9006, and data can be exchanged directly with other information terminals through a connector. In addition, charging can also be performed through the connection terminal 9006. In addition, the charging work can also be performed using wireless power supply instead of through the connection terminal 9006.

[0551] The display device of one embodiment of the present invention can be used for the display portion 9001 of the portable information terminal 9200. Thus, the frame of the portable information terminal 9200 can be narrowed, and the display portion 9001 can display high-quality images and images with a sense of reality.

[0552] Fig.31E , Fig.31F and Figure 31G 1 is a perspective view showing a foldable portable information terminal 9201. Fig.31E is a perspective view of the portable information terminal 9201 in the unfolded state. Fig.31F is a perspective view of a portable information terminal 9201 in a state halfway between an unfolded state and a folded state, Figure 31G 9055. The portable information terminal 9201 is a three-dimensional diagram of a portable information terminal 9201 in a folded state. The portable information terminal 9201 has good portability in the folded state, and has excellent display overview in the unfolded state because it has a large display area that is seamlessly spliced. The display unit 9001 included in the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. By bending the two housings 9000 through the hinges 9055, the portable information terminal 9201 can be reversibly changed from the unfolded state to the folded state. For example, the portable information terminal 9201 can be bent with a curvature radius of more than 1 mm and less than 150 mm.

[0553] The display device of one embodiment of the present invention can be used for the display portion 9001 of the portable information terminal 9201. Thus, the frame of the portable information terminal 9201 can be narrowed, and the display portion 9001 can display high-quality images and images with a sense of reality.

[0554] At least a part of the structural examples described in this embodiment mode and the drawings and the like corresponding to these examples can be implemented in combination with other structural examples or drawings and the like as appropriate.

[0555] At least a part of this embodiment mode can be implemented in combination with other embodiment modes described in this specification as appropriate.

[0556] [Example 1]

[0557] In this embodiment, the results of measuring the drain current-drain voltage characteristics (Id-Vd characteristics) of a transistor provided in a pixel included in a display device are described.

[0558] In this embodiment, for Fig. 15C The Id-Vd characteristics of the transistor 554 provided in the pixel having the structure shown in the figure were measured. Table 1 shows the specifications of the display device provided with the transistor whose Id-Vg characteristics were measured in this embodiment.

[0559] [Table 1]

[0560]

[0561] Fig.32 The measurement results of the Id-Vd characteristics of the transistor are shown. In addition, in this embodiment, three conditions of 1.0V, 1.5V and 2.0V are set as the gate voltage (Vg) applied to the transistor. Fig.32 As shown, it can be confirmed that the transistor is saturated under the gate voltage conditions of the three conditions.

[0562] [Example 2]

[0563] In this embodiment, a scanning transmission electron microscope (STEM) is used to measure the Figure 1 The results of measuring a cross section of a transistor in the display device 10 having the structure shown and the results of measuring the drain current-gate voltage characteristics (Id-Vg characteristics) of the transistor.

[0564] Fig.33 : is a diagram showing the structure of a pixel 34 provided in the display device 10 according to the present embodiment. The pixel 34 includes a transistor M1, a transistor M2, a transistor M3, a transistor M4, a capacitor C1, a capacitor C2, and a light emitting element EL.

[0565] One of the source and drain of the transistor M1 is electrically connected to one of the electrodes of the capacitor C1. The other electrode of the capacitor C1 is electrically connected to one of the source and drain of the transistor M2. One of the source and drain of the transistor M2 is electrically connected to the gate of the transistor M3. The gate of the transistor M3 is electrically connected to one of the electrodes of the capacitor C2. The other electrode of the capacitor C2 is electrically connected to one of the source and drain of the transistor M3. One of the source and drain of the transistor M3 is electrically connected to one of the source and drain of the transistor M4. One of the source and drain of the transistor M4 is electrically connected to the anode of the light emitting element EL.

[0566] The gate of the transistor M1 and the gate of the transistor M4 are electrically connected to the wiring 31_1 used as a scan line. The gate of the transistor M2 is electrically connected to the wiring 31_2 used as a scan line. The other of the source and the drain of the transistor M1 is electrically connected to the wiring 32_1 used as a data line. The other of the source and the drain of the transistor M2 is electrically connected to the wiring 32_2 used as a data line. The other of the source and the drain of the transistor M3 is electrically connected to the supply potential V H The other of the source and drain of the transistor M4 is electrically connected to the wiring supplied with the potential V com The cathode of the light emitting element EL is electrically connected to the wiring supplied with the potential V L Wiring electrical connections.

[0567] The transistors M1 to M4 include back gates in addition to the gates. In the transistors M1, M2 and M4, the back gates are electrically connected to the gates. In addition, the back gate of the transistor M3 is electrically connected to one of the source and the drain of the transistor M3.

[0568] In transistors M1, M2, and M4, the channel length (L) is set to 360 nm, and the channel width (W) is set to 360 nm. In transistor M3, the channel length (L) is set to 1000 nm, and the channel width is set to 360 nm. Furthermore, the capacitance of capacitor C1 is set to 36 fF, and the capacitance of capacitor C2 is set to 33 fF.

[0569] Table 2 shows the specifications of the display device 10 provided with the transistor whose cross section and Id-Vg characteristics were measured in this embodiment.

[0570] [Table 2]

[0571]

[0572] Fig.34 is a STEM image showing a cross section of a transistor. Fig.34 As shown, it can be confirmed that a stacked OS transistor can be formed.

[0573] Fig.35A The measurement results of the Id-Vg characteristics of the transistor provided in the lower layer are shown. Fig.35B The measurement results of the Id-Vg characteristics of the transistors provided in the upper layer are shown. In addition, the channel length (L) of the transistor for measuring the Id-Vg characteristics is set to 360nm, and the channel width (W) of the transistor is set to 360nm. In addition, the drain voltage (Vd) applied to the transistor provided in layer 20 and the transistor provided in layer 30 is set to 0.1V and 3.3V, respectively.

[0574] like Fig.35A and Fig.35B As shown, it can be confirmed that the off-state current of the OS transistor provided in the layer 20 and the OS transistor provided in the layer 30 are both lower than the detection lower limit regardless of the applied drain voltage.

[0575] [Explanation of symbols]

[0576] 10: Display device, 20: Layer, 21: Gate driving circuit, 21a: Gate driving circuit, 21b: Gate driving circuit, 22: Source driving circuit, 23: Region, 23a: Region, 23b: Region, 24: Demultiplexing circuit, 30: Layer, 31: Wiring, 31-1: Wiring, 31-2: Wiring, 31_1: Wiring, 31_2: Wiring, 31a: Wiring, 31b: Wiring, 32: Wiring, 32-1: Wiring, 32-2: Wiring, 32_1: Wiring, 32_2: Wiring, 33: Display unit, 34: Pixel, 35: Wiring, 35a: Wiring, 35b: Wiring, 40: Circuit, 41: Receiving circuit, 42: Serial-parallel conversion circuit, 43: Buffer circuit, 44: Shift Register circuit, 45: latch circuit, 46: DA conversion circuit, 46a: potential generation circuit, 46b: transfer transistor logic circuit, 47: amplifier circuit, 48: resistor, 49: transfer transistor, 51: transistor, 52: transistor, 53: transistor, 54: transistor, 55: transistor, 56: transistor, 57: transistor, 58: transistor, 59: transistor, 60: transistor, 61: transistor, 62: transistor, 63: transistor, 64: capacitor, 65: capacitor, 66: capacitor, 67: source follower circuit, 70: region, 71: transistor, 72: transistor, 73: pseudo transistor, 110: channel formation region, 111: source region, 112: drain region, 11 3: gate electrode, 114: opening, 115: wiring, 116: opening, 117: wiring, 118: opening, 119: opening, 120: opening, 121: wiring, 122: wiring, 123: wiring, 130: channel formation region, 131: source region, 132: drain region, 133: gate electrode, 134: opening, 135: wiring, 136: opening, 137: wiring, 138: opening, 139: opening, 140: opening, 141: wiring, 142: wiring, 143: wiring, 151: semiconductor, 152: conductor, 200: transistor, 200A: transistor, 200B: transistor, 200C: transistor, 205: conductor, 214 : Insulator, 216: Insulator, 222: Insulator, 224: Insulator, 230: Metal Oxide, 230a: Metal Oxide, 230b: Metal Oxide, 230c: Metal Oxide, 240: Conductor, 240a: Conductor, 240b: Conductor, 241: Insulator, 241a: Insulator, 241b: Insulator, 242: Conductor, 242a: Conductor, 242b: Conductor, 243a: Region, 243b: Region, 244: Insulator, 250: Insulator, 252: Metal Oxide, 254: Insulator, 260: Conductor, 260a: Conductor, 260b: Conductor, 270: Insulator, 271: Insulator, 272: Insulator,274: Insulator, 280: Insulator, 281: Insulator, 301a: Conductor, 301b: Conductor, 305: Conductor, 311: Conductor, 313: Conductor, 317: Conductor, 321: Lower electrode, 323: Insulator, 325: Upper electrode, 331: Conductor, 333: Conductor, 335: Conductor, 337: Conductor, 341: Conductor, 343: Conductor, 347: Conductor, 351: Conductor, 353: Conductor, 355: Conductor, 357: Conductor, 361: Insulator, 363: Insulator, 401: Circuit, 403: Element separation layer, 405: Insulator, 407: Insulator, 409: Insulator, 411: Insulator, 413: Insulator, 415: Insulator, 417: Insulator, 419: Insulator, 421: Insulator, 441: Transistor, 443: Conductor, 445: Insulator, 447: Semiconductor region, 449a: Low resistance region, 449b: Low resistance region, 451: Conductor, 453: Conductor, 455: Conductor, 457: Conductor, 459: Conductor, 461: Conductor, 463: Conductor, 465: Conductor, 467: Conductor, 469: Conductor, 471: Conductor, 501: Insulator, 503: Insulator, 505: Insulator, 507: Insulator, 509: Insulator, 511: Transistor, 513: Transistor, 515: Capacitor , 517: capacitor, 519: liquid crystal element, 520: circuit, 521: transistor, 523: light emitting element, 525: transistor, 527: transistor, 531: wiring, 533: wiring, 535: wiring, 537: wiring, 539: wiring, 541: wiring, 543: wiring, 545: wiring, 550: transistor, 552: transistor, 554: transistor, 560: capacitor, 562: capacitor, 570: liquid crystal element, 572: light emitting element, 601: transistor, 602: transistor, 603: transistor, 613: insulator, 614: insulator, 616: insulator, 622: insulator, 624: insulator, 644: insulator, 654: insulator insulator, 674: insulator, 680: insulator, 681: insulator, 701: substrate, 705: substrate, 712: sealant, 716: FPC, 721: hole injection layer, 722: hole transport layer, 723: light emitting layer, 724: electron transport layer, 725: electron injection layer, 730: insulator, 732: sealing layer, 734: insulator, 736: coloring layer, 738: light shielding layer, 750: transistor, 760: connecting electrode, 772: conductor, 774: conductor, 775: liquid crystal element, 776: liquid crystal layer, 778: structure, 780: anisotropic conductor, 782: light emitting element, 786: EL layer, 786a: EL layer, 786b: EL layer,786c: EL layer, 788: conductor, 790: capacitor, 792: charge generation layer, 8000: camera, 8001: housing, 8002: display unit, 8003: operation button, 8004: shutter button, 8006: lens, 8100: viewfinder, 8101: housing, 8102: display unit, 8103: button, 8200: head-mounted display, 8201: mounting portion, 8202: lens, 8203: main body, 8204: display unit, 8205: cable, 8206: battery, 8300: head-mounted display, 8301: housing, 8302: display unit, 8304: fixing tool, 8305: lens, 9000: housing, 9001: display unit, 9003: speaker, 9005: operation key, 9006: connection terminal, 9007: sensor, 9008: microphone, 9050: operation button, 9051: information, 9052: information, 9053: information, 9054: information, 9055: hinge, 9100: television device, 9101: portable information terminal, 9102: portable information terminal, 9200: portable information terminal, 9201: portable information terminal,

Claims

1. A display device comprising a first layer and a second layer stacked together, in, The first layer includes a gate driving circuit and a source driving circuit, The second layer includes a display portion, In the display unit, pixels are arranged in a matrix. The gate driving circuit and the source driving circuit have an area overlapping with the pixel, The gate driving circuit has an area overlapping with the source driving circuit, The source driving circuit is electrically connected to the pixel through a first data line. The source driving circuit is electrically connected to the pixel through a second data line, The source driving circuit has a function of generating a first image signal and supplying the first image signal to the pixel through the first data line. The source driving circuit has a function of generating a second image signal and supplying the second image signal to the pixel through the second data line. Furthermore, the pixel has a function of displaying an image in which an image corresponding to the first image signal and an image corresponding to the second image signal are overlapped.

2. The display device according to claim 1, The display device includes a DA conversion circuit. The DA conversion circuit includes a potential generation circuit and a transmission transistor logic circuit. The potential generating circuit is arranged outside the source driving circuit. The transmission transistor logic circuit is arranged in the source driving circuit, The potential generating circuit has a function of generating a plurality of potentials of different magnitudes. And the transfer transistor logic circuit has a function of receiving image data and outputting any one of the potentials generated by the potential generating circuit according to the digital value of the image data.

3. The display device according to claim 1 or 2, wherein the pixel comprises a display element, And the display element is a light-emitting element.

4. The display device according to claim 3, The display element is an organic EL element.

5. The display device according to claim 4, The organic EL element has a tandem structure.

6. The display device according to claim 1, The pixel includes a display element, a first transistor, a second transistor, a third transistor and a capacitor, One of the source and the drain of the first transistor is electrically connected to one electrode of the capacitor, The other of the source and the drain of the first transistor is electrically connected to the first data line, One of the source and the drain of the second transistor is electrically connected to the other electrode of the capacitor, The other of the source and the drain of the second transistor is electrically connected to the second data line, The other electrode of the capacitor is electrically connected to the gate of the third transistor, And one of the source and the drain of the third transistor is electrically connected to one electrode in the display element.

7. The display device according to claim 6, wherein the first and second transistors include metal oxide in the channel formation region, The metal oxide comprises elements M and Zn, And the element M is Al, Ga, Y or Sn.

8. An electronic device, comprising: The display device according to claim 1; as well as lens.

Images