Movable body

Abstract

Provided is a movable body having a display device that is capable of performing highly-visible display. The movable body has a display unit, an imaging unit, a calculation unit, and a control unit. The display unit has a function of displaying a display image. The imaging unit has a function of acquiring a first captured image including a display image and an outside scene superimposed with the display image. The calculation unit has a function of comparing the color of the display image and the color of the outside scene on the basis of the first captured image, and correcting the color of the display image on the basis of the comparison result. The control unit has a function of controlling travel of the movable body on the basis of the first captured image.

Description

Mobile

[0001] One aspect of the present invention relates to a moving object.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. The technical field of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification and the like include a semiconductor device, a display device, a light-emitting device, a power storage device, an imaging device, a memory device, a driving method thereof, or a manufacturing method thereof.

[0003] Development of in-vehicle displays, which are display devices mounted on moving bodies such as automobiles, is underway. For example, Patent Literature 1 discloses a head-up display, which is a type of in-vehicle display. The head-up display displays an image so as to be superimposed on an external scene viewed through a window such as a windshield. In other words, the head-up display can provide an augmented reality (AR) display.

[0004] JP 2021-36324 A

[0005] In an in-vehicle display that displays AR, such as a head-up display, the displayed image may be difficult to see depending on the external scenery. For example, if the displayed image and the external scenery in the area where the displayed image overlaps are of similar colors, the visibility of the displayed image may be lower than if the colors are of different colors.

[0006] An object of one embodiment of the present invention is to provide a mobile body having a display device capable of displaying a highly visible image. Another object of one embodiment of the present invention is to provide a mobile body having a highly visible image and an outside view. Another object of one embodiment of the present invention is to provide a mobile body having a display device capable of displaying an image based on a driver's state. Another object of one embodiment of the present invention is to provide a mobile body having a display device capable of displaying an image that alleviates the driver's drowsiness. Another object of one embodiment of the present invention is to provide a mobile body that can be controlled according to an outside situation. Another object of one embodiment of the present invention is to provide a mobile body that can suppress the occurrence of an accident. Another object of one embodiment of the present invention is to provide a multifunctional and low-cost mobile body. Another object of one embodiment of the present invention is to provide a highly convenient mobile body. Another object of one embodiment of the present invention is to provide a novel mobile body. Another object of one embodiment of the present invention is to provide a driving method or a control method for the mobile body. Another object of one embodiment of the present invention is to provide a display device included in the moving object and a driving method thereof.

[0007] The problems of one embodiment of the present invention are not limited to the problems listed above. The problems listed above do not preclude the existence of other problems. The other problems are problems not mentioned in this section, which will be described below. Problems not mentioned in this section can be derived by a person skilled in the art from the description in the specification or drawings, and can be appropriately extracted from these descriptions. One embodiment of the present invention solves at least one of the problems listed above and / or other problems.

[0008] One aspect of the present invention is a mobile body having a display unit, an imaging unit, a calculation unit, and a control unit, wherein the display unit has a function of displaying a display image, the imaging unit has a function of acquiring a first captured image including the display image and an external scene superimposed on the display image, the calculation unit has a function of comparing the color of the display image with the color of the external scene based on the first captured image, and correcting the color of the display image based on the result of the comparison, and the control unit has a function of controlling the movement of the mobile body based on the first captured image.

[0009] Alternatively, in the above aspect, the calculation unit may have a function of changing the color of the displayed image to a complementary color of the color of the external scenery.

[0010] Alternatively, in the above aspect, the imaging unit may have a function of acquiring a second captured image including the driver of the moving body, and the calculation unit may have a function of estimating the state of the driver based on the second captured image and correcting the display image based on the estimation result.

[0011] Alternatively, in the above aspect, the second captured image may include the face of the driver.

[0012] Alternatively, in the above aspect, the state of the driver may be drowsiness of the driver.

[0013] Alternatively, in the above aspect, the moving body may have an on-board light, the calculation unit may have a function of acquiring external illuminance based on the first captured image, and the control unit may have a function of controlling the brightness of the on-board light based on the external illuminance.

[0014] Alternatively, one aspect of the present invention is a mobile body having a display unit, an imaging unit, a driving data acquisition unit, and a calculation unit, wherein the display unit has a function of displaying a display image, the imaging unit has a function of acquiring a first captured image including the display image and an external scene superimposed on the display image, and a second captured image including a driver of the mobile body, the driving data acquisition unit has a function of acquiring driving data, the calculation unit has a function of estimating the driver's state based on the second captured image, the calculation unit has a function of estimating the cause of the driver's state based on the first captured image and the driving data, and the calculation unit has a function of correcting the display image based on the cause.

[0015] Alternatively, in the above aspect, the driving data may include at least a change over time in the traveling speed of the mobile object.

[0016] Alternatively, in the above aspect, the state of the driver may be drowsiness of the driver.

[0017] Alternatively, in the above aspect, the second captured image may include the face of the driver.

[0018] Alternatively, in the above aspect, the calculation unit may have a function of detecting an object included in the first captured image, and the calculation unit may have a function of correcting the display image based on the object and the driving data.

[0019] Alternatively, in the above aspect, the driving data may include at least one of an accelerator operation frequency or a brake operation frequency, and the calculation unit may have a function of changing the transmittance of the display image when the accelerator operation frequency or the brake operation frequency is equal to or greater than a specified value.

[0020] Alternatively, in the above aspect, the calculation unit may have a function of changing the transmittance of the display image when a specified number or more of people are detected as objects.

[0021] Alternatively, in the above aspect, the moving body may have a control unit, and the control unit may have a function of controlling the traveling of the moving body based on the first captured image.

[0022] According to one embodiment of the present invention, a mobile body having a display device capable of displaying a highly visible image can be provided. According to another embodiment of the present invention, a mobile body having a display device capable of displaying a display based on a driver's state can be provided. According to another embodiment of the present invention, a mobile body having a display device capable of displaying a display that alleviates drowsiness in a driver can be provided. According to another embodiment of the present invention, a mobile body capable of performing control according to an external situation can be provided. According to another embodiment of the present invention, a mobile body capable of suppressing the occurrence of an accident can be provided. According to another embodiment of the present invention, a multifunctional and low-cost mobile body can be provided. According to another embodiment of the present invention, a highly convenient mobile body can be provided. According to another embodiment of the present invention, a novel mobile body can be provided. According to another embodiment of the present invention, a driving method or a control method for the mobile body can be provided. According to another embodiment of the present invention, a display device included in the mobile body and a driving method thereof can be provided.

[0023] The effects of one embodiment of the present invention are not limited to the effects listed above. The effects listed above do not preclude the existence of other effects. The other effects are described below and are not mentioned in this section. Effects not mentioned in this section can be derived by a person skilled in the art from the description in the specification or drawings, and can be extracted as appropriate from these descriptions. One embodiment of the present invention has at least one of the effects listed above and / or other effects. Therefore, one embodiment of the present invention may not have the effects listed above in some cases.

[0024] FIG. 1A is a block diagram showing an example of the configuration of a moving body. FIG. 1B is a schematic diagram showing an example of the configuration of a moving body. FIGS. 2A and 2B are schematic diagrams showing an example of a display device provided in a moving body. FIGS. 3A and 3B are flowcharts showing an example of a method for driving a moving body. FIGS. 4A and 4B are schematic diagrams showing an example of correction of a display image. FIGS. 5A and 5B are flowcharts showing an example of a method for driving a moving body. FIGS. 6A and 6B are flowcharts showing an example of a method for driving a moving body. FIGS. 7A and 7B are schematic diagrams showing an example of a drowsiness estimation method. FIG. 8 is a flowchart showing an example of a method for driving a moving body. FIGS. 9A and 9B are flowcharts showing an example of a method for driving a moving body. FIGS. 10A and 10B are flowcharts showing an example of a method for driving a moving body. FIGS. 11A and 11B are schematic diagrams showing an example of correction of a display image. FIG. 12A is a block diagram showing an example of the configuration of a display device. FIGS. 12B1 to 12B8 are top views showing example pixel configurations. 13A to 13D are cross-sectional views showing configuration examples of a light-emitting element. FIG. 14A is a top view showing a configuration example of a display device. FIGS. 14B to 14D are cross-sectional views showing a configuration example of a display device. FIGS. 15A to 15D are cross-sectional views showing a configuration example of a display device. FIGS. 16A and 16B are perspective views showing a configuration example of a display device. FIG. 17 is a cross-sectional view showing a configuration example of a display device. FIG. 18 is a cross-sectional view showing a configuration example of a display device. FIG. 19 is a cross-sectional view showing a configuration example of a display device. FIG. 20 is a cross-sectional view showing a configuration example of a display device. FIG. 21A is a top view showing a configuration example of a transistor. FIGS. 21B and 21C are cross-sectional views showing configuration examples of a transistor. FIG. 22A is a diagram explaining classification of IGZO crystal structures. FIG. 22B is a diagram explaining an XRD spectrum of a CAAC-IGZO film. FIG. 22C is a diagram explaining a microelectron beam diffraction pattern of a CAAC-IGZO film. FIGS. 23A to 23E are diagrams showing an example of a moving object. Fig. 24A is a cross-sectional schematic diagram of a display device and a user's eye, Fig. 24B is a schematic diagram illustrating the user's eye and its vicinity, and Fig. 24C is a schematic diagram showing the retinal pattern of the user's eye.

[0025] Hereinafter, embodiments will be described with reference to the drawings. However, it will be readily understood by those skilled in the art that the embodiments can be implemented in many different ways and that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the following description of the embodiments.

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

[0027] In the drawings described in this specification, the size of each component, the thickness of a layer, or an area may be exaggerated for clarity, and therefore, the drawings are not necessarily limited to the scale.

[0028] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components and do not limit the number.

[0029] Furthermore, in this specification and the like, the terms "film" and "layer" can be interchangeable in some cases or depending on the situation. For example, the terms "conductive layer" and "insulating layer" can sometimes be interchangeable with the terms "conductive film" and "insulating film."

[0030] Furthermore, in this specification, "parallel" refers to a state in which two straight lines are arranged at an angle of -10 degrees or more and 10 degrees or less. Therefore, it also includes cases in which the angle is -5 degrees or more and 5 degrees or less. Furthermore, "substantially parallel" refers to a state in which two straight lines are arranged at an angle of -30 degrees or more and 30 degrees or less. Furthermore, "perpendicular" refers to a state in which two straight lines are arranged at an angle of 80 degrees or more and 100 degrees or less. Therefore, it also includes cases in which the angle is 85 degrees or more and 95 degrees or less. Furthermore, "substantially perpendicular" refers to a state in which two straight lines are arranged at an angle of 60 degrees or more and 120 degrees or less.

[0031] In this specification and the like, the EL layer refers to a layer provided between a pair of electrodes of a light-emitting element and containing at least a light-emitting substance (also referred to as a light-emitting layer), or a stack including a light-emitting layer.

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

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

[0034] Embodiment 1 In this embodiment, for example, a moving object which is one embodiment of the present invention will be described with reference to the drawings.

[0035] One aspect of the present invention relates to a mobile body having a display device. The display device may be, for example, a head-up display or a transparent display, and can display an image so as to be superimposed on an external view visible through a window such as a windshield. The mobile body of one aspect of the present invention first acquires a captured image including a display image, which is an image displayed by the display device, and an external view superimposed on the display image. Next, the display image and the external view are compared based on the captured image. Then, the display image is corrected based on the comparison result. This can improve the visibility of the display image. For example, the visibility of the display image can be improved by setting the color of the display image to a complementary color of the color of the external view in the area superimposed on the display image.

[0036] By correcting a display image based on a captured image including a display image and an external scene superimposed on the display image, the display image can be appropriately corrected, even if the display device deteriorates. For example, when a display device has light-emitting elements (also called light-emitting devices) such as organic EL elements as display elements (also called display devices) and the display image is corrected based on the amount of current flowing through the light-emitting elements and the external scene, the display image may not be appropriately corrected if the light-emitting elements deteriorate. This is because, even if the current flowing through the light-emitting elements before and after deterioration of the light-emitting elements is the same, the luminance of the light emitted by the light-emitting elements may differ, for example. On the other hand, when correcting a display image based on a captured image including the display image, the display image can be corrected taking into account changes in luminance due to deterioration of the light-emitting elements, for example. As described above, the display image can be appropriately corrected even if the display device deteriorates.

[0037] Furthermore, the travel of a mobile body of one embodiment of the present invention can be controlled based on the captured image. As a result, the mobile body of one embodiment of the present invention can perform, for example, autonomous driving. By using the same captured image for display image correction and the same captured image for travel control of the mobile body, the same imaging device can be used for correcting the display image and for travel control of the mobile body. This reduces the number of components required for the mobile body compared to when the imaging device used for display image correction and the imaging device used for travel control of the mobile body are different imaging devices. Therefore, the mobile body of one embodiment of the present invention can be a multifunctional and low-cost mobile body.

[0038] Furthermore, the imaging device included in the mobile body of one embodiment of the present invention can capture an image of, for example, the driver of the mobile body. This allows the mobile body of one embodiment of the present invention to estimate, for example, the state of the driver of the mobile body, and thus the drowsiness of the driver of the mobile body. Therefore, the mobile body of one embodiment of the present invention can correct a display image based on the state of the driver, for example, to correct the display image so as to reduce the driver's drowsiness. Here, for example, the imaging device capturing an image of the driver of the mobile body of one embodiment of the present invention can be the same imaging device as the imaging device used for correcting the display image and for controlling the traveling of the mobile body. For example, by using an omnidirectional camera as the imaging device, the imaging device capturing an image of the driver of the mobile body of one embodiment of the present invention and the imaging device used for correcting the display image and for controlling the traveling of the mobile body can be the same imaging device.

[0039] 1A is a block diagram showing an example of the configuration of a mobile body 10, which is a mobile body according to one aspect of the present invention. The mobile body 10 corresponds to a vehicle, for example, and specific examples include an automobile, a bus, and a train. In the following description, the mobile body will be described as an automobile unless otherwise specified.

[0040] The mobile body 10 includes an imaging unit 12, a driving data acquisition unit 14, a calculation unit 16, an image generation unit 18, a display unit 22, and a control unit 24. The configuration example shown in FIG. 1A can be said to be a configuration example of a mobile body system included in the mobile body 10.

[0041] The imaging unit 12 has a function of capturing an image and acquiring the captured image. The imaging unit 12 can be configured, for example, in such a manner that pixels each having a light receiving element (also referred to as a light receiving device) are arranged in a matrix, and can capture an image using the light receiving element.

[0042] The driving data acquisition unit 14 has a function of acquiring driving data that represents the driving state of the mobile object 10. The driving data may represent, for example, a change in the traveling speed of the mobile object 10 over time. The driving data may also represent, for example, the frequency of accelerator operation and the frequency of brake operation. In addition, the driving data may represent the traveling time, traveling distance, steering wheel rotation amount, engine speed, etc. of the mobile object 10. The driving data acquisition unit 14 may include, for example, a tachograph, such as a digital tachograph.

[0043] The calculation unit 16 has a function of performing calculations necessary to realize the functions of the moving body 10. The calculation unit 16 has a function of performing calculations based on, for example, captured images. The calculation unit 16 also has a function of performing calculations based on, for example, driving data. The calculation unit 16 can have, for example, a CPU (Central Processing Unit).

[0044] The calculation unit 16 may also have a function of performing calculations using machine learning. In this case, the calculation unit 16 preferably has a function of performing calculations using a neural network. For example, the calculation unit 16 preferably has a function of performing calculations using one or more neural networks selected from a feedforward neural network (FFNN), a convolutional neural network (CNN), a recurrent neural network (RNN), and a long short-term memory unit (LSTM).

[0045] When the calculation unit 16 has a function of performing calculations using machine learning, it is preferable that the calculation unit 16 has a GPU (Graphics Processing Unit). By having a GPU, the calculation unit 16 can perform parallel calculations at high speed, and therefore, for example, the calculation unit 16 can perform matrix calculations (product-sum calculations) required for machine learning at high speed.

[0046] The image generating unit 18 has a function of generating image data, for example, based on the calculation result by the calculation unit 16.

[0047] The display unit 22 has a function of displaying an image corresponding to the image data generated by the image generation unit 18. In this specification and the like, an image displayed on the display unit 22, for example, is referred to as a display image.

[0048] The display unit 22 may have a configuration in which pixels each having a display element are arranged in a matrix. Light-emitting elements, specifically, organic EL elements, for example, may be used as the display elements. Furthermore, inorganic EL elements, quantum dots, light-emitting diodes (LEDs), etc. may also be used as the light-emitting elements. When LEDs are used as the light-emitting elements, micro-LEDs are particularly preferred because they can display high-quality images on the display unit 22. Liquid crystal elements (also referred to as liquid crystal devices) or digital micromirror devices (DMDs) may also be used as the display elements. Furthermore, a laser display may also be used for the display unit 22.

[0049] The control unit 24 has a function of controlling the driving of the mobile body 10. For example, the control unit 24 has a function of accelerating and decelerating (braking) the mobile body 10. The control unit 24 also has a function of controlling the traveling direction of the mobile body 10, that is, a function of steering. The control unit 24 can control the driving of the mobile body 10 based on the calculation results by the calculation unit 16.

[0050] The mobile body 10 has the imaging unit 12, the calculation unit 16, and the control unit 24, and thus has the function of performing autonomous driving. For example, the calculation unit 16 performs calculation processing such as object recognition based on the captured image acquired by the imaging unit 12, and the control unit 24 controls the driving of the mobile body 10 based on the calculation results, thereby enabling the mobile body 10 to perform autonomous driving.

[0051] 1A illustrates an example of a configuration in which the moving object 10 includes an imaging unit 12, a driving data acquisition unit 14, a calculation unit 16, an image generation unit 18, a display unit 22, and a control unit 24. However, the present invention is not limited to this. For example, the moving object 10 may include a sensor unit in addition to the above configuration. The sensor unit may include, for example, a sensor (including a function for measuring force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared light). The sensor may preferably be, for example, a distance image sensor such as a LIDAR (Light Detection and Ranging) sensor or a sensor using a ToF (Time of Flight) system.

[0052] 1B is a schematic diagram showing an example of the configuration of the mobile object 10, and is an example of the appearance of the mobile object 10 including the mobile object system shown in FIG. 1A. The mobile object 10 has a window 31, a light 33, a display device 35, an imaging device 37, and a semiconductor device 39.

[0053] The window portion 31 may be, for example, a front window. Alternatively, for example, a side window or a rear window may be used as the window portion 31. A person riding in the vehicle 10, such as the driver of the vehicle 10, can view the outside scenery through the window portion 31.

[0054] The light 33 may be, for example, a headlight. It may also be, for example, a cornering light, a fog light, a backup light, or a backup fog light. By turning on the light 33, it is possible to ensure external illumination even in an environment with low external illumination, such as at night or in a tunnel. The light 33 may be referred to as an in-vehicle light.

[0055] The display device 35 includes, for example, the display unit 22 shown in Fig. 1A. Note that the display device 35 may include, for example, the image generating unit 18 shown in Fig. 1A.

[0056] The display image displayed by the display device 35 can be displayed so as to be superimposed on the outside scenery viewed through the window 31. Therefore, compared to when an image is displayed without being superimposed on the outside scenery, for example, the amount of eye movement of the driver of the mobile body 10 can be reduced, thereby reducing the burden on the driver of the mobile body 10.

[0057] The imaging device 37 has, for example, the imaging unit 12 shown in Fig. 1A. The imaging device 37 can capture an image of the outside world through, for example, the window 31. Here, when the display device 35 displays an image so as to be superimposed on the outside world view visible through the window 31, the imaging device 37 can acquire a captured image that includes the display image and the outside world view. Note that the captured image acquired by the imaging device 37 does not necessarily include either the display image or the outside world view.

[0058] 1B , the position of the image capturing device 37 may be located, for example, behind the rearview mirror of the vehicle 10. The image capturing device 37 may also be located outside the vehicle, for example, on the headlights, on the license plate, or in the vicinity thereof. Alternatively, the image capturing device 37 may be located on the steering wheel.

[0059] The imaging device 37 may have a function to acquire not only an image including the external scenery but also an image including, for example, the driver of the mobile body 10. Here, it is preferable that the imaging device 37 of the mobile body 10 is an imaging device capable of capturing images in all directions, such as an omnidirectional camera, because one imaging device 37 can acquire both an image including the external scenery and an image including the driver of the mobile body 10.

[0060] The semiconductor device 39 includes, for example, the driving data acquisition unit 14, the calculation unit 16, the image generation unit 18, and the control unit 24 shown in FIG. 1A. Note that if the display device 35 includes the image generation unit 18, the semiconductor device 39 may be configured without the image generation unit 18. The semiconductor device 39 may include, for example, a CPU. The semiconductor device 39 may also include, for example, a GPU.

[0061] 2A and 2B are schematic diagrams showing an example of the display device 35. The display device 35 shown in Fig. 2A is a head-up display, and projects an image onto the window portion 31 as indicated by an arrow 44. This causes a display image 42 to be displayed as a virtual image, and a person riding in the vehicle 10 can view the display image 42 as indicated by an arrow 46.

[0062] 2A may have a function of displaying an image displayed by a display device of an electronic device such as a smartphone or a tablet. For example, an image displayed by the electronic device such as a smartphone or a tablet may be reflected by the display device 35 and projected onto the window 31. Alternatively, image data representing an image displayed by the electronic device such as a smartphone or a tablet may be input to the display device 35, and the display device 35 may display an image corresponding to the image data. As described above, the display device 35 can change the display image 42 in conjunction with the electronic device.

[0063] 2B is a transparent display, and a person riding in the vehicle 10 can see the outside world even through the display device 35. Therefore, the display device 35 can display a display image 42 so as to be superimposed on the outside world seen through the window portion 31.

[0064] Furthermore, when the display device 35 is a transparent display, the display device 35 can be attached to the window portion 31. When attaching the display device 35 to the window portion 31, it is preferable that the display device 35 is flexible, because even if the window portion 31 has a curved portion, the display device 35 can be attached along the curved portion.

[0065] <Example of a driving method of a moving body -1> Fig. 3A is a flowchart showing an example of a driving method of the moving body 10 shown in Fig. 1A and Fig. 1B. The moving body 10 can correct a displayed image by the method shown in Fig. 3A.

[0066] First, the imaging unit 12 acquires a captured image including a display image and an external scene superimposed on the display image (step S01). Note that the captured image does not necessarily include either the display image or the external scene. Next, the calculation unit 16 compares the display image with the external scene based on the captured image (step S02). Note that if the captured image does not include the display image, the calculation unit 16 can compare the captured image with image data generated by the image generation unit 18, for example.

[0067] Thereafter, the calculation unit 16 corrects the display image based on the comparison result (step S03). For example, the display image is corrected so as to improve the visibility of the display image. The correction of the display image can be performed, for example, by the calculation unit 16 correcting the image data generated by the image generation unit 18. Note that the display image may also be corrected taking into account the location, season, weather, time, etc. After step S03, for example, the process returns to step S01. Alternatively, the operation shown in FIG. 3A is terminated.

[0068] FIG. 3B is a flowchart showing a more specific example of the driving method shown in FIG. 3A. First, the imaging unit 12 acquires a captured image including a display image displayed in the window 31 by the display unit 22 and an external scene superimposed on the display image (step S01a). As described above, the captured image does not necessarily include either the display image or the external scene. Next, the calculation unit 16 compares the color of the display image with the color of the external scene in the area superimposed on the display image based on the captured image (step S02a). As described above, if the captured image does not include a display image, the calculation unit 16 can compare the captured image with, for example, image data generated by the image generation unit 18. Then, based on the comparison result, the calculation unit 16 corrects the color of the display image (step S03a). After step S03a, the process returns to, for example, step S01a. Alternatively, the operation shown in FIG. 3B is terminated.

[0069] For example, when the color of the display image and the color of the external scenery in the area overlapping the display image are similar colors, the visibility of the display image may be lower than when the colors are different. Therefore, for example, the color of the display image is corrected to a color different from the color of the external scenery in the area overlapping the display image. For example, the color of the display image is made the complementary color of the color of the external scenery in the area overlapping the display image. For example, when the color of the external scenery in the area overlapping the display image is red, the color of the display image is made cyan. Furthermore, when the color of the external scenery in the area overlapping the display image is green, the color of the display image is made magenta. Furthermore, when the color of the external scenery in the area overlapping the display image is blue, the color of the display image is made yellow. As a result, the visibility of the display image can be improved.

[0070] The color of the displayed image can be corrected by changing at least one of the hue, brightness, and saturation. For example, if image data representing a full-color display image includes data representing a red image, data representing a green image, and data representing a blue image, the color of the displayed image can be corrected by interchanging these data.

[0071] The correction of the display image is not limited to color correction. For example, the calculation unit 16 may correct the luminance of the display image. Furthermore, the calculation unit 16 may correct the contrast of the display image. For example, the calculation unit 16 can correct the luminance of the display image according to the external illuminance acquired based on the captured image. For example, the visibility of the display image can be improved by increasing the luminance of the display image when the external illuminance is high and decreasing the luminance of the display image when the external illuminance is low. Furthermore, if the luminance of a specific area of ​​the external scenery included in the captured image is high due to, for example, direct sunlight, the visibility of the display image can be improved by correcting the display image so that the luminance of an area of ​​the display image that overlaps with the specific area is higher than the luminance of other areas.

[0072] Furthermore, the calculation unit 16 may change the display position of the display image. Furthermore, the calculation unit 16 may enlarge or reduce the size of characters or graphics included in the display image. Furthermore, the calculation unit 16 may change the font of characters included in the display image, or may add a border to the characters.

[0073] 4A and 4B are schematic diagrams showing an example of correction of a display image. In the example shown in FIG. 4A, the display image 42 is black, and in the example shown in FIG. 4B, the display image 42 is white. Here, for example, if the display image 42 is white in the example shown in FIG. 4A, the display image 42 blends in with the building 48a, and the visibility of the display image 42 is reduced. Also, for example, if the display image 42 is black in the example shown in FIG. 4B, the display image 42 blends in with the building 48b, and the visibility of the display image 42 is reduced. Therefore, for example, by making the display image 42 black in the example shown in FIG. 4A and making the display image 42 white in the example shown in FIG. 4B, the visibility of the display image 42 can be improved.

[0074] The display image may be corrected by machine learning. For example, the display image may be corrected by a neural network. For example, a feature of the captured image may be extracted by a CNN, and the display image may be corrected based on the feature to improve visibility.

[0075] As described above, the traveling of the mobile body 10 can be controlled using captured images, thereby enabling, for example, autonomous driving. Here, by using the same captured image for display image correction and the same captured image for traveling control of the mobile body 10, the same imaging device can be used for correcting the display image and for controlling the traveling of the mobile body. This reduces the number of components required for the mobile body 10 compared to when the imaging device used for display image correction and the imaging device used for traveling control of the mobile body are different imaging devices. Therefore, the mobile body 10 can be a multifunctional and low-cost mobile body.

[0076] <Example of driving method of moving body - 2> Fig. 5A is a flowchart showing an example of a driving method of the moving body 10 shown in Fig. 1A and Fig. 1B, which is different from the method shown in Fig. 3A. In the method shown in Fig. 5A, the displayed image can be corrected taking into account the state of the display unit 22.

[0077] First, the imaging unit 12 acquires a captured image including a display image and an external scene superimposed on the display image (step S11). Next, the calculation unit 16 compares the display image with the external scene based on the captured image (step S12). For example, as in the case where the moving object 10 is driven by the method shown in FIG. 3A, the captured image does not need to include the display image. In this case, the calculation unit 16 can compare the captured image with image data generated by the image generation unit 18, for example.

[0078] Next, the calculation unit 16 estimates the state of the display unit 22. For example, it estimates the state of deterioration or burn-in of the display unit 22 (step S13). After that, the calculation unit 16 corrects the display image based on the comparison result between the display image and the external view and the state of the display unit 22 (step S14). For example, the calculation unit 16 corrects the display image so as to improve the visibility of the display image while suppressing the occurrence of problems caused by the state of the display unit 22, such as the display image not being displayed. After step S14, for example, the process returns to step S11. Alternatively, the operation shown in FIG. 5A is terminated.

[0079] 5B is a flowchart showing a more specific method of the driving method shown in FIG. 5A. First, the imaging unit 12 acquires a captured image including a display image and an external scene superimposed on the display image (step S11a). Next, the calculation unit 16 compares the display image with the external scene in the area superimposed on the display image based on the captured image (step S12a). After that, the temperature of the display unit 22 is measured (step S13a-1). For example, the imaging unit 12 is provided with a temperature sensor such as an infrared sensor, and the temperature sensor measures the temperature of the display unit 22. Note that it is preferable that the temperature sensor measure not only the temperature of the display unit 22 but also, for example, the air temperature inside the moving object 10.

[0080] Next, the calculation unit 16 estimates the deterioration state of the display unit 22 based on the display image included in the captured image and the temperature of the display unit 22 (step S13a-2). For example, the calculation unit 16 can estimate the deterioration state of the display unit 22 based on the brightness of the display image included in the captured image and the temperature of the display unit 22. For example, if the temperature of the display unit 22 is high relative to the brightness of the display image, it can be estimated that the current flowing through the light-emitting elements provided in the display unit 22 is easily converted into heat, and the display unit 22 has deteriorated. Here, if the temperature inside the mobile body 10 is measured in step S13a-1, for example, the deterioration state of the display unit 22 can be estimated based on the measured temperature. For example, if the temperature inside the mobile body 10 is high, it can be estimated that the display unit 22 has not deteriorated, even if the temperature of the display unit 22 is high. Furthermore, the deterioration state of the display unit 22 may be estimated taking into account the external scenery included in the captured image. For example, when the display unit 22 is exposed to direct sunlight, it can be estimated that the display unit 22 has not deteriorated even if the temperature of the display unit 22 is high.

[0081] Thereafter, the calculation unit 16 corrects the displayed image based on the comparison result between the displayed image and the external scene and the deterioration state of the display unit 22 (step S14a). After step S14a, the process returns to step S11a, for example, or the operation shown in FIG. 5B is terminated.

[0082] In step S14a, the calculation unit 16 corrects the display image so as to enhance the visibility of the display image while suppressing deterioration of the display unit 22, similar to the examples shown in FIGS. 3A and 3B. For example, the luminance of the display image can be reduced within a range that does not reduce visibility. For example, the luminance can be reduced in areas of the display image where the luminance is equal to or greater than a specified value. The display image may also be corrected taking into account the hue, lightness, or saturation of the display image. For example, reducing the luminance of colors with low hue and saturation, such as achromatic colors such as white, can reduce deterioration of the display unit 22 while suppressing a significant reduction in visibility.

[0083] Furthermore, when deterioration of the display unit 22 is detected, for example, a message indicating that the display unit 22 has deteriorated can be displayed on the display unit 22. For example, when the engine of the mobile body 10 is started, a message indicating that the display unit 22 has deteriorated can be displayed on the display unit 22. This makes it possible to prevent problems such as the display unit 22 not displaying an image while the mobile body 10 is traveling.

[0084] As described above, by correcting the display image based on a captured image including the display image and the external scene, the display image can be appropriately corrected even if the display unit 22 has deteriorated. For example, if the display unit 22 has light-emitting elements and the display image is corrected based on the amount of current flowing through the light-emitting elements and the external scene, the display image may not be appropriately corrected if the light-emitting elements have deteriorated. This is because, for example, the luminance of light emitted by the light-emitting elements may differ even if the current flowing through the light-emitting elements before and after deterioration of the light-emitting elements is the same. On the other hand, when the display image is corrected based on a captured image including the display image, the display image can be corrected taking into account changes in luminance due to deterioration of the light-emitting elements, for example. As described above, the display image can be appropriately corrected even if the display unit 22 has deteriorated.

[0085] 5B , the calculation unit 16 may estimate, for example, the state of burn-in on the display unit 22. For example, the calculation unit 16 can estimate the state of burn-in on the display unit 22 based on the period during which an image is displayed on the display unit 22 and changes in the displayed image over time. When burn-in on the display unit 22 is detected, the calculation unit 16 can correct the hue of the displayed image so that the burn-in becomes less noticeable, for example.

[0086] <Example of driving method of moving body -3> Fig. 6A is a flowchart showing an example of a driving method of the moving body 10 shown in Fig. 1A and Fig. 1B, which is different from the methods shown in Fig. 3A and Fig. 5A, etc. In the method shown in Fig. 6A, it is possible to correct the displayed image based on the internal state of the moving body 10, for example, the state of the driver of the moving body 10.

[0087] First, the image capturing unit 12 captures a first captured image including a display image and an external scene superimposed on the display image. The image capturing unit 12 also captures a second captured image including the driver (step S21). Note that the first captured image does not necessarily include either the display image or the external scene.

[0088] Here, it is preferable that the imaging device 37 of the moving body 10 is an imaging device capable of capturing omnidirectional images, such as an omnidirectional camera, because the first captured image and the second captured image can be acquired by the same imaging device. By using an imaging device capable of capturing omnidirectional images as the imaging device 37, it is possible to capture images not only of the front of the moving body 10 but also of the sides and rear, for example. As a result, even if the moving body 10 has a display device that projects images not only on the front window but also on the side windows or rear window, the imaging device 37 can capture images projected by these display devices. Furthermore, the control unit 24 can control the operation of the moving body 10 based on, for example, not only the state of the front of the moving body 10 but also the state of the sides and rear.

[0089] Next, the calculation unit 16 compares the display image with the external view based on the first captured image. The calculation unit 16 also estimates the state of the driver of the vehicle 10 based on the second captured image (step S22). Note that if the first captured image does not include a display image, the calculation unit 16 can compare the captured image with image data generated by the image generation unit 18, for example.

[0090] Thereafter, the calculation unit 16 corrects the display image based on the comparison result between the display image and the external scene and the estimation result of the driver's state (step S23). For example, the display image is corrected to improve the visibility of the display image and to prevent accidents caused by the driver's state. After step S23, the process returns to step S21, for example. Alternatively, the operation shown in FIG. 6A is terminated.

[0091] 6B is a flowchart showing a more specific method of the driving method shown in FIG. 6A. First, the imaging unit 12 acquires a first captured image including a display image and an external scene superimposed on the display image. The imaging unit 12 also acquires a second captured image including the driver's face (step S21a). As described above, the first captured image does not necessarily include either the display image or the external scene.

[0092] Next, the calculation unit 16 compares the display image with the external view based on the first captured image. The calculation unit 16 also estimates the drowsiness of the driver of the vehicle 10 based on the second captured image (step S22a). As described above, if the first captured image does not include a display image, the calculation unit 16 can compare the captured image with, for example, image data generated by the image generation unit 18.

[0093] Thereafter, the calculation unit 16 corrects the display image based on the comparison result between the display image and the external scene and the estimation result of the driver's drowsiness (step S23a). For example, the display image is corrected to improve the visibility of the display image and relieve the driver's drowsiness. After step S23a, the process returns to step S21a, for example. Alternatively, the operation shown in FIG. 6B is terminated.

[0094] For example, when the driver of the mobile body 10 is estimated to be drowsy, the display image may be corrected by increasing the brightness of the display image, increasing the contrast of the display image, changing the color of the display image, for example, to a reddish color, or enlarging the display image. Furthermore, the mobile body 10 may perform processing such as blinking the display image, changing the display position of the display image, or displaying a message encouraging the driver to take a break. Furthermore, the mobile body 10 may perform, for example, emitting a warning sound, vibrating the seat in which the driver is seated or the seat belt worn by the driver, or emitting a gas with an odor intended to alleviate drowsiness. Furthermore, when the driver is estimated to be very drowsy, the control unit 24 may stop the mobile body 10. For example, the control unit 24 may blink the hazard lights of the mobile body 10 and stop the mobile body 10 to avoid contact with other mobile bodies. Here, when the control unit 24 stops the mobile body 10, it is preferable to move the mobile body 10 to, for example, the shoulder of the road so as not to obstruct the passage of other mobile bodies.

[0095] 7A and 7B are schematic diagrams showing an example of a method for estimating drowsiness. Drowsiness can be estimated based on the state of the eyes, for example.

[0096] FIG. 7A is a schematic diagram showing an example of the eye state of a person experiencing drowsiness, and FIG. 7B is a schematic diagram showing an example of the eye state of a person not experiencing drowsiness. As shown in FIGS. 7A and 7B , when a person experiences drowsiness, the eyelid opening degree may be lower than when the person does not experience drowsiness. For example, the distance x1 between the upper and lower eyelids shown in FIG. 7A is shorter than the distance x2 between the upper and lower eyelids shown in FIG. 7B . The eyelid opening degree can be calculated based on the distance between the upper and lower eyelids. For example, the distance between the upper and lower eyelids at the time of measuring the eyelid opening degree can be calculated by dividing the distance between the upper and lower eyelids by the maximum distance between the upper and lower eyelids. By using such a value as the eyelid opening degree, the calculation unit 16 can estimate the presence or absence of drowsiness with high accuracy, even if there are individual differences in the distances x1 and x2.

[0097] Furthermore, when a driver is drowsy, the eye closure time during blinking may be longer than when the driver is not drowsy, and the change in pupil diameter over time (pupil diameter fluctuation) may be greater. Based on the above-mentioned indices, the calculation unit 16 can estimate the driver's drowsiness using the second captured image including the face of the driver of the mobile object 10. For example, the calculation unit 16 can estimate the driver's drowsiness using multiple second captured images acquired by the imaging unit 12 at regular time intervals.

[0098] Note that drowsiness may be estimated based on the presence or absence of yawning, head movement, etc. Drowsiness may also be estimated based on driving data. For example, the calculation unit 16 may detect the meandering rate or steering amount of the mobile body 10 based on the driving data, and estimate the drowsiness of the driver of the mobile body 10.

[0099] The calculation unit 16 can estimate the drowsiness of the driver by machine learning, for example, by using a neural network. For example, the calculation unit 16 can estimate the drowsiness of the driver by using a neural network that can handle time-series data, such as an RNN or an LSTM.

[0100] Note that the state of the driver of the mobile body 10 that the calculation unit 16 can estimate is not limited to drowsiness, and the calculation unit 16 may have a function to estimate fatigue, emotions, illness, or the like of the driver of the mobile body 10. In this case, when the calculation unit 16 estimates that the driver is experiencing increased fatigue, emotional arousal, or symptoms of illness, for example, the display unit 22 can display a message urging the driver to take a break as a display image.

[0101] <Example of driving method of moving body -4> Fig. 8 is a flowchart showing an example of a driving method of the moving body 10 shown in Fig. 1A and Fig. 1B that is different from the methods shown in Fig. 3A, Fig. 5A, Fig. 6A, etc. In the method shown in Fig. 8, the brightness of the light 33 is adjusted based on the captured image.

[0102] First, the imaging unit 12 acquires a captured image including a display image and an external scene superimposed on the display image (step S31). Note that the captured image does not necessarily include either the display image or the external scene.

[0103] Next, the calculation unit 16 acquires the external illuminance based on the captured image (step S32). If an area with high illuminance is present in the external scenery included in the captured image, the calculation unit 16 estimates the cause of the high external illuminance (steps S33 and S34). If the area with high external illuminance is due to the high brightness of the light 33, the control unit 24 reduces the brightness of the light 33. If the area with high external illuminance is not due to the light 33, the process returns to step S31 (steps S35 and S36).

[0104] Here, in step S34, if the illuminance is low in many areas of the external scenery included in the captured image, for example, because it is nighttime or inside a tunnel, but the illuminance is high in some areas, and the high illuminance corresponds to the illuminance of the light 33, the calculation unit 16 can infer that the cause of the high illuminance is the light emitted by the light 33. Furthermore, the calculation unit 16 may perform object recognition based on the captured image, for example, and infer the cause of the existence of an area with high external illuminance based on the object recognition. For example, if the captured image includes a street light or other moving object and light emitted by these objects is irradiating the window portion 31, the calculation unit 16 can infer that the cause of the high illuminance is not the light emitted by the light 33.

[0105] The reason for the high external illuminance may be estimated by machine learning, for example, by using a neural network. For example, the reason for the high external illuminance may be estimated by using a CNN.

[0106] By reducing the brightness of the light 33 in step S36, it is possible to improve the visibility of the display image, for example, when the visibility of the display image is reduced due to light emitted by the light 33. On the other hand, by estimating the cause of high external illuminance in step S34, it is possible to prevent the light 33 from being operated, for example, during the day. Furthermore, it is possible to prevent the light 33 from being operated, for example, even at night, when there is an area where the external illuminance is high due to light emitted by something other than the light 33.

[0107] Next, similar to step S31, the imaging unit 12 acquires a captured image including a display image and an external scene superimposed on the display image (step S37). Then, similar to step S32, the calculation unit 16 acquires external illuminance based on the captured image (step S38). If the external illuminance is less than the specified value, the luminance of the light 33 is increased and the process returns to step S31. On the other hand, if the external illuminance is equal to or greater than the specified value, the luminance of the light 33 is not changed and the process returns to step S31 (steps S39 and S40). In step S39, for example, it is possible to determine whether the average luminance value of the entire captured image is less than or equal to the specified value. Note that if it is determined in step S33 that no area with high external illuminance exists, steps S34 to S38 can be omitted and step S39 can be performed. After step S40, the process returns to step S31, for example. Alternatively, the operation shown in FIG. 8 is terminated.

[0108] By performing steps S37 to S40, it is possible to prevent a situation in which sufficient external illumination cannot be ensured due to a decrease in the brightness of the light 33. As described above, by driving the moving body 10 in the method shown in FIG. 8 , it is possible to improve the visibility of both the displayed image and the external scenery. For example, if the light 33 is a headlight, the light emitted by the light 33 may be set to low beam in step S36 and the light emitted by the light 33 may be set to high beam in step S40. Here, it is preferable to take the external scenery into consideration, particularly when the light emitted by the light 33 is set to high beam. For example, if the captured image includes a moving body other than the moving body 10, it is preferable not to set the light emitted by the light 33 to high beam.

[0109] In addition, if the imaging unit 12 has a function of acquiring an image including, for example, the face of the driver of the mobile body 10, the calculation unit 16 may estimate the state of the driver of the mobile body 10 using the image and adjust the brightness of the light 33 according to the estimation result. For example, if it is estimated in step S34 that there is an area with high external illuminance due to high luminance of the light 33 and it is estimated that the driver of the mobile body 10 is feeling dazzled, for example, by squinting, the calculation unit 16 may reduce the brightness of the light 33 in step S36. Furthermore, if it is determined in step S39 that the external illuminance is less than a specified value and it is estimated that the driver of the mobile body 10 is leaning forward, for example, and therefore the visibility of the external scenery is not sufficiently ensured, the calculation unit 16 may increase the brightness of the light 33 in step S40. As described above, for example, the brightness of the light 33 can be adjusted based on the state of the driver of the mobile body 10, thereby improving the convenience of the mobile body 10.

[0110] The calculation unit 16 may also correct the display image. For example, the display image can be corrected by the same method as shown in Fig. 3A or 3B. Furthermore, if the imaging unit 12 has a function of acquiring an image including, for example, the driver of the vehicle 10, the display image can be corrected by the same method as shown in Fig. 6A or 6B.

[0111] <Example of driving method of moving body -5> Fig. 9A is a flowchart showing an example of a driving method for the moving body 10 shown in Fig. 1A and Fig. 1B, which is different from Fig. 3A, Fig. 5A, Fig. 6A, Fig. 8, etc. In the method shown in Fig. 9A, the display image can be corrected based on driving data.

[0112] First, the imaging unit 12 acquires a first captured image including a display image and an external scene superimposed on the display image. The imaging unit 12 also acquires a second captured image including the driver. Furthermore, the driving data acquisition unit 14 acquires driving data (step S51). Note that the first captured image does not necessarily include either the display image or the external scene.

[0113] Here, as in the case where the moving body 10 is driven by the method shown in FIG. 6A, it is preferable that the imaging device 37 possessed by the moving body 10 is an imaging device capable of omnidirectional imaging, such as an omnidirectional camera, because this allows the first captured image and the second captured image to be obtained by the same imaging device.

[0114] Next, the calculation unit 16 analyzes the first captured image, the second captured image, and the driving data (step S52). After that, the calculation unit 16 corrects the display image based on the analysis results (step S53). After step S53, the process returns to step S51, for example, or the operation shown in FIG. 9A is terminated.

[0115] 9B is a flowchart showing a more specific method of the driving method shown in FIG. 9A. First, the imaging unit 12 acquires a first captured image including a display image and an external scene superimposed on the display image. The imaging unit 12 also acquires a second captured image including the driver's face. Furthermore, the driving data acquisition unit 14 acquires driving data (step S51a). As described above, the first captured image does not necessarily include either the display image or the external scene.

[0116] Next, the calculation unit 16 estimates the drowsiness of the driver of the moving object 10 based on the second captured image (step S52a-1). The drowsiness estimation can use the method described with reference to Figs. 7A and 7B.

[0117] If it is estimated that the driver is not drowsy, for example, if the parameter indicating the driver's drowsiness is less than a specified value, the process returns to step S51a. On the other hand, if it is estimated that the driver is drowsy, for example, if the parameter indicating the driver's drowsiness is equal to or greater than a specified value, the calculation unit 16 estimates the cause of the drowsiness based on the first captured image and the driving data (steps S52a-2 and S52a-3).

[0118] Thereafter, the calculation unit 16 corrects the display image based on the cause of the drowsiness so as to eliminate the drowsiness (step S53a). After step S53a, the process returns to step S51a, for example, or the operation shown in FIG. 9B is ended.

[0119] In step S53a, for example, it is assumed that the driving data indicates that the travel speed of the mobile body 10 changes little over time or that the steering wheel rotation amount is small. Furthermore, it is assumed that the first captured image indicates that the external scenery changes little over time and has low contrast. In this case, it can be estimated that the cause of the drowsiness of the driver of the mobile body 10 is a monotonous and less stimulating external scenery. Therefore, the calculation unit 16 can alleviate the driver's drowsiness by, for example, continuously changing the display position, color, or size of the display image or increasing the contrast of the display image. On the other hand, if it is estimated that the cause of the drowsiness of the driver of the mobile body 10 is low external illuminance, it can alleviate the driver's drowsiness by increasing the luminance of the display image. Note that the cause of the drowsiness of the driver of the mobile body 10 may be estimated by machine learning, for example, using a neural network.

[0120] <Example 6 of a driving method for a moving body> FIG. 10A is a flowchart showing an example of a driving method for the moving body 10 shown in FIGS. 1A and 1B, which is different from the methods shown in FIGS. 3A, 5A, 6A, 8, and 9A.

[0121] First, the imaging unit 12 acquires a captured image including a display image and an external scene superimposed on the display image. The driving data acquisition unit 14 acquires driving data (step S61). Note that the captured image does not necessarily include either the display image or the external scene.

[0122] Next, the calculation unit 16 estimates the external environment based on the captured image and the driving data (step S62). After that, the calculation unit 16 corrects the display image based on the external environment (step S63). After step S63, the process returns to step S61, for example. Alternatively, the operation shown in FIG. 10A is terminated.

[0123] 10B is a flowchart showing a more specific method of the driving method shown in FIG. 10A. First, the imaging unit 12 acquires a captured image including a display image and an external scene superimposed on the display image. The driving data acquisition unit 14 also acquires driving data (step S61a). As described above, the captured image does not necessarily include either the display image or the external scene.

[0124] Next, the calculation unit 16 detects an object included in the captured image (step S62a-1). The object detection can be performed by, for example, pattern matching. Alternatively, the object detection can be performed by, for example, a neural network, specifically, a CNN.

[0125] Next, the calculation unit 16 estimates the external situation based on the detected object and the driving data (step S62a-2). After that, the calculation unit 16 corrects the display image based on the estimation result of the external situation (step S63a). For example, the display image is corrected to prevent the occurrence of an accident. After step S63a, the process returns to step S61a, for example. Alternatively, the operation shown in FIG. 10B is terminated.

[0126] 11A and 11B are schematic diagrams showing an example of display image correction. In the example shown in FIG. 11A, no objects such as people or moving bodies are detected in step S62a-1. In this case, even if the driver of the moving body 10 pays attention to the display image 42, the possibility of a serious accident such as a personal injury accident occurring is low. Therefore, the display unit 22 can display the display image 42 so that the display image 42 stands out.

[0127] On the other hand, in the example shown in FIG. 10B , many people 49 are detected in step S62a-1. Furthermore, the driving data indicates that the frequency of accelerator operation and braking operation of the mobile body 10 is high. In this case, it is estimated that the driver of the mobile body 10 is paying great attention to avoid contact with the person 49. If the display image 42 is prominently displayed in this situation, the driver's attention may be diverted to the display image 42, and the display image 42 may obstruct the driver's view. This may result in a serious accident, such as the mobile body 10 contacting the person 49.

[0128] Therefore, by making the display image 42 less noticeable, the occurrence of accidents can be reduced. For example, accidents can be reduced by increasing the transmittance of the display image 42, reducing the luminance of the display image 42, reducing the saturation or brightness of the display image 42, making the display image 42 a similar color to the background, reducing the size of the display image 42, making the display image 42 content that does not attract the driver's attention, or not displaying the display image 42. That is, the mobile body 10 can have one or more functions selected from a function to change the transmittance of the display image, a function to change the luminance of the display image, a function to change the saturation or brightness of the display image, etc.

[0129] Note that if the visibility of the display image 42 becomes too low, the driver of the mobile body 10 may instead turn his or her attention to the display image 42, and therefore, it is preferable that the calculation unit 16 take this into consideration when correcting the display image 42. For example, the imaging unit 12 may acquire an image including the driver of the mobile body 10, and the calculation unit 16 may then estimate the driver's condition, such as fatigue, and correct the display image 42 based on the estimated result of the driver's condition. For example, by estimating changes in the driver's fatigue over time, the display image 42 may be corrected so that the driver's fatigue is reduced as much as possible and the driver can continue to pay necessary attention.

[0130] As described above, when the frequency of accelerator operation or brake operation of the mobile object 10, which is represented by, for example, driving data, is equal to or greater than a specified value and a specified number of people are detected, the calculation unit 16 can correct the display image 42 to increase the transmittance of the display image 42. Note that the estimation of the external situation may be performed by machine learning, for example, by a neural network.

[0131] Furthermore, the estimation of the external environment does not necessarily require the use of either the detection results of objects included in the captured image or the driving data. For example, if the frequency of accelerator operation or brake operation of the mobile body 10 is equal to or greater than a specified value, the display image 42 may be corrected without considering the detection results of objects included in the captured image. Furthermore, if a specified number or more of people are detected in the captured image, the display image 42 may be corrected without considering the driving data. For example, if a specified number or more of people are detected ahead of the mobile body 10, the display image 42 may be corrected without considering the driving data.

[0132] At least part of the configuration examples described in this embodiment and the corresponding drawings, etc. can be appropriately combined with other configuration examples, drawings, etc. For example, a moving object of one embodiment of the present invention can adjust the luminance of an in-vehicle light while correcting a display image.

[0133] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0134] (Embodiment 2) In this embodiment, a detailed configuration example of the display device 35 shown in Embodiment 1 will be described. Fig. 12A is a block diagram illustrating the display device 35. The display device 35 has a display area 235, a first drive circuit unit 231, and a second drive circuit unit 232. The display area 235 has a plurality of pixels 230 arranged in a matrix. The pixels 230 have display elements, and the display elements can be light-emitting elements such as organic EL elements.

[0135] The circuit included in the first drive circuit unit 231 functions as, for example, a scanning line drive circuit. The circuit included in the second drive circuit unit 232 functions as, for example, a signal line drive circuit. Note that some kind of circuit may be provided at a position facing the first drive circuit unit 231 across the display area 235. Note that some kind of circuit may be provided at a position facing the second drive circuit unit 232 across the display area 235. Note that the circuits included in the first drive circuit unit 231 and the second drive circuit unit 232 may be collectively referred to as a "peripheral drive circuit."

[0136] The peripheral driving circuit can be made of various circuits such as a shift register, a level shifter, an inverter, a latch, an analog switch, a logic circuit, etc. The peripheral driving circuit can be made of transistors, capacitors, etc.

[0137] For example, a transistor having a metal oxide in a channel formation region (hereinafter referred to as an OS transistor) may be used as a transistor constituting the pixel 230, and a transistor having silicon in a channel formation region (hereinafter referred to as a Si transistor) may be used as a transistor constituting the peripheral driver circuit. OS transistors have a low off-state current, which allows for reduced power consumption. Furthermore, Si transistors have a higher operating speed than OS transistors, so they are suitable for use in the peripheral driver circuit. Note that, depending on the display device, OS transistors may be used for both the transistor constituting the pixel 230 and the transistors constituting the peripheral driver circuit and the peripheral driver circuit. Furthermore, depending on the display device, Si transistors may be used for both the transistor constituting the pixel 230 and the transistors constituting the peripheral driver circuit and the peripheral driver circuit. Furthermore, depending on the display device, Si transistors may be used for the transistor constituting the pixel 230, and OS transistors may be used for the transistors constituting the peripheral driver circuit and the peripheral driver circuit.

[0138] Both Si transistors and OS transistors may be used as transistors forming the pixel 230. Both Si transistors and OS transistors may be used as transistors forming the peripheral driver circuits.

[0139] Examples of materials used for Si transistors include single-crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, a transistor having low-temperature polysilicon (LTPS) in a semiconductor layer (hereinafter referred to as an LTPS transistor) can be used. The LTPS transistor has high field-effect mobility and good frequency characteristics.

[0140] By using Si transistors such as LTPS transistors, circuits that need to be driven at high frequencies (such as source driver circuits) can be built on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0141] An OS transistor has significantly higher field-effect mobility than a transistor using amorphous silicon. Furthermore, an OS transistor has significantly lower source-drain leakage current in an off state (hereinafter also referred to as off-state current), and can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display device.

[0142] The off-state current of the OS transistor per 1 μm of channel width at room temperature is 1 aA (1×10 −１８ A) Below, 1zA (1×10 −２１ A) or less, or 1yA (1 x 10 −２４ Note that the off-state current of a Si transistor per 1 μm of channel width at room temperature can be 1 fA (1×10 −１５ A) More than 1pA (1×10 −１２ Therefore, it can be said that the off-state current of an OS transistor is about 10 orders of magnitude lower than that of a Si transistor.

[0143] Furthermore, to increase the emission luminance of a light-emitting element included in a pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting element. To achieve this, it is necessary to increase the source-drain voltage of a driving transistor included in the pixel circuit. Since an OS transistor has a higher source-drain withstand voltage than a Si transistor, a high voltage can be applied between the source and drain of the OS transistor. Thus, by using an OS transistor as the driving transistor included in a pixel circuit, it is possible to increase the amount of current flowing through the light-emitting element and increase the emission luminance of the light-emitting element.

[0144] Furthermore, when a transistor operates in a saturation region, an OS transistor can reduce the change in source-drain current with respect to a change in gate-source voltage compared to a Si transistor. Therefore, by using an OS transistor as a driving transistor included in a pixel circuit, the current flowing between the source and drain can be precisely controlled by changing the gate-source voltage, thereby controlling the amount of current flowing to a light-emitting element. This allows for a larger gradation level in the pixel circuit.

[0145] Furthermore, in terms of saturation characteristics of the current that flows when a transistor operates in a saturation region, an OS transistor can pass a more stable current (saturation current) than a Si transistor, even when the source-drain voltage gradually increases. Therefore, by using an OS transistor as a driving transistor, a stable current can be passed to a light-emitting element, even when the current-voltage characteristics of the light-emitting element containing an EL material vary. In other words, when an OS transistor operates in a saturation region, the source-drain current hardly changes even when the source-drain voltage increases, thereby stabilizing the light-emitting luminance of the light-emitting element.

[0146] As described above, by using an OS transistor for a driving transistor included in a pixel circuit, it is possible to achieve "suppression of black floating," "increase in light-emitting luminance," "multiple gradations," "suppression of variations in light-emitting elements," and the like.

[0147] The display device 35 also has a plurality of wirings 236 that are arranged approximately parallel to each other and whose potential is controlled by a circuit included in the first drive circuit unit 231, and a plurality of wirings 237 that are arranged approximately parallel to each other and whose potential is controlled by a circuit included in the second drive circuit unit 232.

[0148] 12A shows an example in which the wiring 236 and the wiring 237 are connected to the pixel 230. However, the wiring 236 and the wiring 237 are just an example, and the wirings connected to the pixel 230 are not limited to the wiring 236 and the wiring 237.

[0149] 12B1 to 12B8 are top views showing exemplary configurations of pixels 240 including a pixel 230. For example, a pixel 230 that controls red light, a pixel 230 that controls green light, and a pixel 230 that controls blue light can be combined to function as a single pixel 240, and the light emission amount (light emission brightness) of each pixel 230 can be controlled to achieve a full-color display. Thus, each of the three pixels 230 functions as a subpixel. That is, each of the three subpixels controls the light emission amount, etc., of red light, green light, or blue light (see FIG. 12B1). The light colors controlled by each of the three subpixels are not limited to a combination of red (R), green (G), and blue (B), but may also be cyan (C), magenta (M), and yellow (Y) (see FIG. 12B2).

[0150] Furthermore, the three pixels 230 constituting one pixel 240 may be arranged in a delta arrangement (see FIG. 12B3). Specifically, the three pixels 230 constituting one pixel 240 may be arranged so that the lines connecting the center points of each pixel 230 form a triangle.

[0151] Furthermore, the areas of the three sub-pixels (pixels 230) do not have to be the same. If the luminous efficiency and reliability differ depending on the luminous color, the area of ​​the sub-pixel may be changed for each luminous color (see FIG. 12B4).

[0152] Alternatively, four subpixels may be combined to function as one pixel. For example, a subpixel that controls white light may be added to three subpixels that control red, green, and blue light, respectively (see FIG. 12B5). Adding a subpixel that controls white light can increase the brightness of the display area. Alternatively, a subpixel that controls yellow light may be added to three subpixels that control red, green, and blue light, respectively (see FIG. 12B6). Alternatively, a subpixel that controls white light may be added to three subpixels that control cyan, magenta, and yellow light, respectively (see FIG. 12B7).

[0153] By increasing the number of sub-pixels that function as one pixel and by appropriately combining sub-pixels that control red, green, blue, cyan, magenta, yellow, and other colors, it is possible to improve the reproducibility of intermediate tones, thereby improving display quality.

[0154] The pixels 240 may include, for example, pixels 230 that control red light, pixels 230 that control green light, and pixels 230 that control blue light, as well as pixels 230 that control infrared light (IR) and pixels 233 that detect light (see FIG. 12B8). The pixels 233 include light-receiving elements.

[0155] The pixel 230 that controls infrared light can be used as a light source, and the infrared light emitted by the pixel 230 can be detected by the pixel 233 .

[0156] 12B8 shows an example in which pixel 233 has the lowest aperture ratio among pixel 230 controlling red light, pixel 230 controlling green light, pixel 230 controlling blue light, pixel 230 controlling infrared light, and pixel 233. A narrow light-receiving area of ​​pixel 233 narrows the imaging range, making it possible to suppress blurring in the imaging result and improve resolution. This is preferable because it enables high-definition or high-resolution imaging. The aperture ratios of pixel 230 controlling red light, pixel 230 controlling green light, pixel 230 controlling blue light, pixel 230 controlling infrared light, and pixel 233 can each be determined appropriately.

[0157] 12B8 , the pixel 240 has a light-receiving function, and therefore, contact or proximity of an object can be detected while displaying an image. Furthermore, the display device of one embodiment of the present invention includes subpixels that emit infrared light, and therefore, the subpixels can be used to display an image while emitting infrared light as a light source. In other words, the display device of one embodiment of the present invention has a high affinity with functions other than the display function (here, the light-receiving function).

[0158] The light receiving element included in the pixel 240 shown in FIG. 12B8 may be used as a touch sensor, a non-contact sensor, or the like.

[0159] Here, a touch sensor or non-contact sensor can detect the proximity or contact of an object (such as a finger, hand, or pen). A touch sensor can detect an object when the electronic device and the object are in direct contact with each other. A non-contact sensor can detect an object even if the object does not come into contact with the electronic device. For example, a display device (or electronic device) is preferably configured to detect an object when the distance between the display device (or electronic device) and the object is between 0.1 mm and 300 mm, preferably between 3 mm and 50 mm. This configuration enables the electronic device to be operated without the object directly touching it, in other words, the display device can be operated in a non-contact (touchless) manner. This configuration reduces the risk of the electronic device becoming dirty or scratched. Alternatively, the electronic device can be operated without the object directly touching dirt (e.g., dust, viruses, etc.) attached to the electronic device.

[0160] The non-contact sensor function can also be called a hover sensor function, a hover-touch sensor function, a near-touch sensor function, a touchless sensor function, etc. The touch sensor function can also be called a direct touch sensor function, for example.

[0161] Furthermore, the display device of one embodiment of the present invention can have a variable refresh rate. For example, the refresh rate can be adjusted (for example, within a range of 0.01 Hz to 240 Hz) depending on the content displayed on the display device, thereby reducing power consumption. Furthermore, driving that reduces the power consumption of the display device by driving it at a reduced refresh rate may be called idling stop (IDS) driving.

[0162] The drive frequency of the touch sensor or near-touch sensor may be changed depending on the refresh rate. For example, if the refresh rate of the display device is 120 Hz, the drive frequency of the touch sensor or near-touch sensor may be set to a frequency higher than 120 Hz (typically 240 Hz). This configuration enables low power consumption and an increased response speed of the touch sensor or near-touch sensor.

[0163] The display device of one embodiment of the present invention can reproduce color gamuts of various standards, such as the Phase Alternating Line (PAL) standard and the National Television System Committee (NTSC) standard used in television broadcasting, the standard RGB (sRGB) standard and the Adobe RGB standard widely used in display devices used in electronic devices such as personal computers, digital cameras, and printers, and the ITU-R BT.2000 standard used in HDTV (High Definition Television, also called Hi-Vision). It is possible to reproduce the color gamut of standards such as the International Telecommunication Union Radiocommunication Sector Broadcasting Service (Television) 709 (International Telecommunication Union Radiocommunication Sector Broadcasting Service (Television) 709) standard, the Digital Cinema Initiatives P3 (DCI-P3) standard used in digital cinema projection, and the ITU-R BT. 2020 (REC. 2020 (Recommendation 2020)) standard used in UHDTV (Ultra High Definition Television, also known as Super Hi-Vision).

[0164] Furthermore, by arranging the pixels 240 in a 1920 x 1080 matrix, a display device 35 capable of full-color display at a resolution of so-called full high-definition (also referred to as "2K resolution," "2K1K," or "2K") can be realized. Furthermore, by arranging the pixels 240 in a 3840 x 2160 matrix, for example, a display device 35 capable of full-color display at a resolution of so-called ultra high-definition (also referred to as "4K resolution," "4K2K," or "4K") can be realized. Furthermore, by arranging the pixels 240 in a 7680 x 4320 matrix, for example, a display device 35 capable of full-color display at a resolution of so-called super high-definition (also referred to as "8K resolution," "8K4K," or "8K") can be realized. By increasing the number of pixels 240, a display device 35 capable of full-color display at a resolution of 16K or 32K can also be realized.

[0165] The pixel density of the display area 235 is preferably 100 ppi to 10,000 ppi, more preferably 1,000 ppi to 10,000 ppi. For example, it may be 2,000 ppi to 6,000 ppi, or 3,000 ppi to 5,000 ppi.

[0166] There is no particular limitation on the aspect ratio of the display area 235. The display area 235 of the display device 35 can accommodate various aspect ratios, such as 1:1 (square), 4:3, 16:9, and 16:10.

[0167] The diagonal size of the display area 235 may be 0.1 inches or more and 100 inches or less, and may be 100 inches or more.

[0168] The diagonal size of the display area 235 can be 0.1 inches or more and 5.0 inches or less, preferably 0.5 inches or more and 2.0 inches or less, and more preferably 1 inch or more and 1.7 inches or less. For example, the diagonal size of the display area 235 may be 1.5 inches or close to 1.5 inches. By setting the diagonal size of the display area 235 to 2.0 inches or less, preferably close to 1.5 inches, it becomes possible to process the display area 235 in a single exposure process using an exposure device (typically a scanner device), thereby improving the productivity of the manufacturing process.

[0169] <Configuration Example of Light-Emitting Element> The light-emitting element included in the pixel 230 will be described below.

[0170] 13A , the light-emitting element 161 included in the pixel 230 includes an EL layer 172 between a pair of electrodes (conductive layers 171 and 173). The EL layer 172 can be configured with a plurality of layers, such as a layer 4420, a light-emitting layer 4411, and a layer 4430. The layer 4420 can include, for example, a layer containing a substance with high electron-injection properties (electron-injection layer) and a layer containing a substance with high electron-transport properties (electron-transport layer). The light-emitting layer 4411 includes, for example, a light-emitting compound. The layer 4430 can include, for example, a layer containing a substance with high hole-injection properties (hole-injection layer) and a layer containing a substance with high hole-transport properties (hole-transport layer).

[0171] A structure including the layer 4420, the light-emitting layer 4411, and the layer 4430 provided between a pair of electrodes can function as a single light-emitting unit, and the structure of FIG. 13A is referred to as a single structure in this specification and the like.

[0172] 13B shows a modified example of the EL layer 172 included in the light-emitting element 161 shown in Fig. 13A. Specifically, the light-emitting element 161 shown in Fig. 13B includes a layer 4430-1 on the conductive layer 171, a layer 4430-2 on the layer 4430-1, a light-emitting layer 4411 on the layer 4430-2, a layer 4420-1 on the light-emitting layer 4411, a layer 4420-2 on the layer 4420-1, and a conductive layer 173 on the layer 4420-2. For example, when the conductive layer 171 is an anode and the conductive layer 173 is a cathode, the layer 4430-1 functions as a hole injection layer, the layer 4430-2 functions as a hole transport layer, the layer 4420-1 functions as an electron transport layer, and the layer 4420-2 functions as an electron injection layer. Alternatively, when the conductive layer 171 is a cathode and the conductive layer 173 is an anode, the layer 4430-1 functions as an electron injection layer, the layer 4430-2 functions as an electron transport layer, the layer 4420-1 functions as a hole transport layer, and the layer 4420-2 functions as a hole injection layer. With such a layer structure, carriers can be efficiently injected into the light-emitting layer 4411, and the efficiency of carrier recombination in the light-emitting layer 4411 can be increased.

[0173] Note that a structure in which a plurality of light-emitting layers (light-emitting layer 4411, light-emitting layer 4412, light-emitting layer 4413) are provided between the layer 4420 and the layer 4430 as shown in FIG. 13C is also an example of a single structure.

[0174] 13D , a configuration in which a plurality of light-emitting units (EL layers 172 a and 172 b) are connected in series via an intermediate layer (charge generation layer) 4440 is referred to as a tandem structure or a stack structure in this specification and the like. Note that the tandem structure makes it possible to realize a light-emitting element capable of emitting light with high brightness.

[0175] Furthermore, when the light-emitting element 161 has a tandem structure as shown in FIG. 13D , the EL layer 172 a and the EL layer 172 b may emit the same light. For example, the EL layer 172 a and the EL layer 172 b may both emit green light. When the display region 235 includes three subpixels, R, G, and B, each of which includes a light-emitting element, the light-emitting elements of the subpixels may be arranged in a tandem structure. Specifically, the EL layer 172 a and the EL layer 172 b of the R subpixel each include a material capable of emitting red light, the EL layer 172 a and the EL layer 172 b of the G subpixel each include a material capable of emitting green light, and the EL layer 172 a and the EL layer 172 b of the B subpixel each include a material capable of emitting blue light. In other words, the light-emitting layer 4411 and the light-emitting layer 4412 may be made of the same material. By making the EL layers 172a and 172b emit light of the same color, the current density per unit of emitted light luminance can be reduced, thereby improving the reliability of the light-emitting element 161.

[0176] The light-emitting color of the light-emitting element can be red, green, blue, cyan, magenta, yellow, white, or the like, depending on the material constituting the EL layer 172. Furthermore, the color purity can be further improved by providing the light-emitting element with a microcavity structure.

[0177] The light-emitting layer preferably contains two or more types of light-emitting materials that emit light such as R (red), G (green), B (blue), Y (yellow), or O (orange). A light-emitting element that emits white light preferably has a configuration in which the light-emitting layer contains two or more types of light-emitting materials. To obtain white light emission, light-emitting materials may be selected such that the respective emissions of the two or more light-emitting materials have a complementary color relationship. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary colors, a light-emitting element that emits white light as a whole can be obtained. The same applies to a light-emitting element having three or more light-emitting layers.

[0178] The light-emitting layer preferably contains two or more light-emitting materials that emit light of R (red), G (green), B (blue), Y (yellow), O (orange), or the like.

[0179] Examples of light-emitting materials include fluorescent materials, phosphorescent materials, inorganic compounds (e.g., quantum dot materials), and materials that exhibit thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) materials). As the TADF material, a material that is in thermal equilibrium between a singlet excited state and a triplet excited state may be used. Such TADF materials have a short emission lifetime (excitation lifetime), which can suppress a decrease in efficiency in a light-emitting element in a high-brightness region.

[0180] <Method of Forming Light-Emitting Element> An example of a method of forming the light-emitting element 161 will be described below.

[0181] FIG. 14A shows a schematic top view of the light-emitting element 161. The light-emitting element 161 includes a plurality of light-emitting elements 161R that exhibit red light, a plurality of light-emitting elements 161G that exhibit green light, and a plurality of light-emitting elements 161B that exhibit blue light. In FIG. 14A, the symbols R, G, and B are assigned within the light-emitting region of each light-emitting element to easily distinguish between the light-emitting elements. The configuration of the light-emitting element 161 shown in FIG. 14A may be referred to as an SBS (Side By Side) structure. The configuration shown in FIG. 14A illustrates a configuration having three colors, red (R), green (G), and blue (B), but is not limited to this. For example, a configuration having four or more colors may also be used.

[0182] The light emitting elements 161R, 161G, and 161B are arranged in a matrix. Fig. 14A shows a so-called stripe arrangement in which light emitting elements of the same color are arranged in one direction. Note that the arrangement of the light emitting elements is not limited to this, and arrangement methods such as a delta arrangement or a zigzag arrangement may also be applied, or a pentile arrangement may also be used.

[0183] 14B is a schematic cross-sectional view corresponding to the dashed-dotted line A1-A2 in FIG. 14A . FIG. 14B shows cross sections of the light-emitting elements 161R, 161G, and 161B. The light-emitting elements 161R, 161G, and 161B are each provided on an insulating layer 363 and include a conductive layer 171 functioning as a pixel electrode and a conductive layer 173 functioning as a common electrode. The insulating layer 363 can be an inorganic insulating film or an organic insulating film, or both. It is preferable to use an inorganic insulating film as the insulating layer 363. Examples of inorganic insulating films include oxide insulating films and nitride insulating films such as a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, an aluminum oxynitride film, and a hafnium oxide film.

[0184] In this specification, a nitride oxide refers to a compound containing more nitrogen than oxygen. An oxynitride refers to a compound containing more oxygen than nitrogen. The content of each element can be measured, for example, by Rutherford backscattering spectrometry (RBS).

[0185] The light-emitting element 161R has an EL layer 172R between a conductive layer 171 functioning as a pixel electrode and a conductive layer 173 functioning as a common electrode. The EL layer 172R contains a light-emitting organic compound that emits light having an intensity at least in the red wavelength range. The EL layer 172G of the light-emitting element 161G contains a light-emitting organic compound that emits light having an intensity at least in the green wavelength range. The EL layer 172B of the light-emitting element 161B contains a light-emitting organic compound that emits light having an intensity at least in the blue wavelength range.

[0186] The EL layer 172R, the EL layer 172G, and the EL layer 172B may each have one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer in addition to a layer containing a light-emitting organic compound (light-emitting layer).

[0187] The conductive layer 171 functioning as a pixel electrode is provided for each light-emitting element. The conductive layer 173 functioning as a common electrode is provided as a continuous layer common to each light-emitting element. A conductive film that is transparent to visible light is used for either the conductive layer 171 functioning as a pixel electrode or the conductive layer 173 functioning as a common electrode, and a conductive film that is reflective is used for the other. By making the conductive layer 171 functioning as a pixel electrode light-transmitting and the conductive layer 173 functioning as a common electrode light-reflective, a bottom-emission display device can be obtained. Conversely, by making the conductive layer 171 functioning as a pixel electrode reflective and the conductive layer 173 functioning as a common electrode light-transmitting, a top-emission display device can be obtained. Note that by making both the conductive layer 171 functioning as a pixel electrode and the conductive layer 173 functioning as a common electrode light-transmitting, a dual-emission display device can also be obtained.

[0188] An insulating layer 272 is provided to cover an end portion of the conductive layer 171 functioning as a pixel electrode. The end portion of the insulating layer 272 preferably has a tapered shape. The insulating layer 272 can be formed using a material similar to that of the insulating layer 363.

[0189] The EL layer 172R, the EL layer 172G, and the EL layer 172B each have a region in contact with the top surface of the conductive layer 171 that functions as a pixel electrode, and a region in contact with the surface of the insulating layer 272. Ends of the EL layer 172R, the EL layer 172G, and the EL layer 172B are located on the insulating layer 272.

[0190] 14B, a gap is provided between two EL layers between light-emitting elements of different colors. In this manner, it is preferable that the EL layer 172R, the EL layer 172G, and the EL layer 172B are not in contact with each other. This can effectively prevent current from flowing through two adjacent EL layers, thereby preventing unintended light emission (also known as crosstalk). This can improve contrast and realize a display device with high display quality.

[0191] The EL layer 172R, the EL layer 172G, and the EL layer 172B can be separately formed by a vacuum deposition method using a shadow mask such as a metal mask. Alternatively, they may be separately formed by a photolithography method. By using the photolithography method, it is possible to realize a high-definition display device that is difficult to achieve when using a metal mask.

[0192] In this specification etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. Also, in this specification etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure. Because a display device with an MML structure is fabricated without using a metal mask, it has a higher degree of design freedom in terms of pixel arrangement, pixel shape, and the like than a display device with an FMM structure or an MM structure.

[0193] In the manufacturing method of a display device with an MML structure, the island-shaped EL layer is not formed by a metal mask pattern, but is formed by forming the EL layer on the entire surface and then processing it. Therefore, it is possible to realize a high-definition display device or a display device with a high aperture ratio, which has been difficult to achieve until now. Furthermore, since the EL layer can be made separately for each color, it is possible to realize a display device with extremely vivid, high contrast, and high display quality. Furthermore, by providing a sacrificial layer (also called a mask layer) on the EL layer, damage to the EL layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting element.

[0194] Furthermore, the display device of one embodiment of the present invention can have a structure in which an insulator covering an edge of a pixel electrode is not provided. In other words, the display device of one embodiment of the present invention has a structure in which an insulator is not provided between the pixel electrode and the EL layer. With this structure, light emitted from the EL layer can be efficiently extracted, thereby significantly reducing viewing angle dependency. For example, in the display device of one embodiment of the present invention, the viewing angle (the maximum angle at which a certain contrast ratio is maintained when the screen is viewed from an oblique direction) can be set to a range of 100° to less than 180°, preferably 150° to 170°. Note that the above viewing angle can be applied to both the vertical and horizontal directions. The display device of one embodiment of the present invention can improve viewing angle dependency and image visibility.

[0195] When a display device is formed using a fine metal mask (FMM) structure, restrictions may be imposed on the pixel arrangement, for example. The FMM structure will now be described.

[0196] To fabricate an FMM structure, a metal mask (also referred to as an FMM) with openings is set opposite the substrate so that the EL material can be deposited in the desired area during EL deposition. Then, EL deposition is performed through the FMM, depositing the EL material in the desired area. As the substrate size increases during EL deposition, the FMM size and weight also increase. Furthermore, the FMM may be deformed during EL deposition, for example, due to heat applied to the FMM. Alternatively, a method of applying a certain tension to the FMM during EL deposition is also available, so the weight and strength of the FMM are important parameters.

[0197] Therefore, when designing the pixel arrangement of a device with an FMM structure, for example, the above parameters must be taken into consideration and certain limitations must be considered. On the other hand, a display device according to one embodiment of the present invention can have an MML structure, which provides excellent advantages, such as a higher degree of freedom in pixel arrangement configuration than an FMM structure. This configuration is also highly compatible with, for example, flexible devices, and allows various circuit arrangements for either or both of the pixels and the drive circuit.

[0198] In addition, a protective layer 271 is provided over the conductive layer 173 functioning as a common electrode to cover the light-emitting elements 161R, 161G, and 161B. The protective layer 271 has a function of preventing impurities such as water from diffusing from above to each light-emitting element.

[0199] The protective layer 271 may have, for example, a single-layer structure or a stacked structure including at least an inorganic insulating film. Examples of inorganic insulating films include oxide films or nitride films such as a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, an aluminum oxynitride film, and a hafnium oxide film. Alternatively, a semiconductor material such as indium gallium oxide or indium gallium zinc oxide (IGZO) may be used for the protective layer 271. Note that the protective layer 271 may be formed by an atomic layer deposition (ALD) method, a chemical vapor deposition (CVD) method, or a sputtering method. Note that, although a structure including an inorganic insulating film is exemplified as the protective layer 271, the present invention is not limited thereto. For example, the protective layer 271 may have a stacked structure of an inorganic insulating film and an organic insulating film.

[0200] When indium gallium zinc oxide is used as the protective layer 271, it can be processed by wet etching or dry etching. For example, when IGZO is used as the protective layer 271, a chemical solution such as oxalic acid, phosphoric acid, or a mixed chemical solution (for example, a mixed chemical solution of phosphoric acid, acetic acid, nitric acid, and water (also referred to as a mixed acid aluminum etching solution)) can be used. Note that the mixed acid aluminum etching solution can have a volume ratio of phosphoric acid:acetic acid:nitric acid:water of approximately 53.3:6.7:3.3:36.7.

[0201] 14C shows a different example. Specifically, Fig. 14C shows a light-emitting element 161W that emits white light. The light-emitting element 161W includes an EL layer 172W that emits white light between a conductive layer 171 that functions as a pixel electrode and a conductive layer 173 that functions as a common electrode.

[0202] The EL layer 172W may be configured by stacking two or more light-emitting layers selected so that the emitted light colors are complementary to each other. Alternatively, a stacked EL layer may be used in which a charge generating layer is sandwiched between the light-emitting layers.

[0203] 14C shows three light-emitting elements 161W lined up. A colored layer 264R is provided on the top of the left light-emitting element 161W. The colored layer 264R functions as a bandpass filter that transmits red light. Similarly, a colored layer 264G that transmits green light is provided on the top of the center light-emitting element 161W, and a colored layer 264B that transmits blue light is provided on the top of the right light-emitting element 161W. This allows the display device to display color images.

[0204] Here, the EL layer 172W and the conductive layer 173 functioning as a common electrode are separated between two adjacent light-emitting elements 161W. This prevents unintended light emission due to current flowing through the EL layer 172W between the two adjacent light-emitting elements 161W. In particular, when a stacked EL layer in which a charge generation layer is provided between two light-emitting layers is used as the EL layer 172W, the higher the resolution, i.e., the smaller the distance between adjacent pixels, the more pronounced the effect of crosstalk becomes, resulting in a decrease in contrast. Therefore, by using this configuration, a display device that combines high resolution and high contrast can be realized.

[0205] The EL layer 172W and the conductive layer 173 functioning as a common electrode are preferably separated by photolithography, which allows the distance between light-emitting elements to be narrowed, thereby realizing a display device with a higher aperture ratio than when a shadow mask such as a metal mask is used.

[0206] In the case of a bottom-emission light-emitting element, a colored layer may be provided between the conductive layer 171 functioning as a pixel electrode and the insulating layer 363 .

[0207] FIG. 14D shows an example different from the above. Specifically, FIG. 14D shows a configuration in which an insulating layer 272 is not provided between the light-emitting element 161R, the light-emitting element 161G, and the light-emitting element 161B. This configuration allows a display device with a high aperture ratio. Furthermore, by not providing the insulating layer 272, the unevenness of the light-emitting element 161 is reduced, thereby improving the viewing angle of the display device. Specifically, the viewing angle can be set to 150° or more and less than 180° degrees, preferably 160° or more and less than 180° degrees, and more preferably 160° or more and less than 180° degrees.

[0208] The protective layer 271 covers the side surfaces of the EL layer 172R, the EL layer 172G, and the EL layer 172B. This configuration can suppress impurities (typically, water, etc.) that can enter from the side surfaces of the EL layer 172R, the EL layer 172G, and the EL layer 172B. Furthermore, the leakage current between adjacent light-emitting elements 161 is reduced, thereby improving the color saturation and contrast ratio and reducing power consumption.

[0209] 14D , the top surfaces of the conductive layer 171, the EL layer 172R, and the conductive layer 173 are generally the same. This structure can be formed collectively using a resist mask or the like after the conductive layer 171, the EL layer 172R, and the conductive layer 173 are formed. This process can also be called self-aligned patterning, since the EL layer 172R and the conductive layer 173 are processed using the conductive layer 173 as a mask. While the EL layer 172R has been described here, the EL layer 172G and the EL layer 172B can also have a similar structure.

[0210] 14D shows a structure in which a protective layer 273 is further provided on the protective layer 271. For example, the protective layer 271 is formed using an apparatus (typically, an ALD apparatus) capable of depositing a film with high coverage, and the protective layer 273 is formed using an apparatus (typically, a sputtering apparatus) capable of depositing a film with lower coverage than the protective layer 271, thereby making it possible to provide a region 275 between the protective layer 271 and the protective layer 273. In other words, the region 275 is located between the EL layer 172R and the EL layer 172G, and between the EL layer 172G and the EL layer 172B.

[0211] The region 275 contains, for example, one or more elements selected from air, nitrogen, oxygen, carbon dioxide, and Group 18 elements (typically, helium, neon, argon, xenon, krypton, etc.). The region 275 may also contain, for example, a gas used when forming the protective layer 273. For example, when the protective layer 273 is formed by sputtering, the region 275 may contain one or more of the above Group 18 elements. When the region 275 contains a gas, the gas can be identified by, for example, gas chromatography. Alternatively, when the protective layer 273 is formed by sputtering, the gas used during sputtering may also be contained in the protective layer 273. In this case, when the protective layer 273 is analyzed by, for example, energy dispersive X-ray analysis (EDX analysis), elements such as argon may be detected.

[0212] Furthermore, when the refractive index of region 275 is lower than the refractive index of protective layer 271, light emitted from EL layer 172R, EL layer 172G, or EL layer 172B is reflected at the interface between protective layer 271 and region 275. This may prevent light emitted from EL layer 172R, EL layer 172G, or EL layer 172B from entering adjacent pixels. This prevents light of different colors from being mixed in with neighboring pixels, thereby improving the display quality of the display device.

[0213] 14D , the area between light-emitting element 161R and light-emitting element 161G or the area between light-emitting element 161G and light-emitting element 161B (hereinafter simply referred to as the distance between the light-emitting elements) can be narrowed. Specifically, the distance between the light-emitting elements can be set to 1 μm or less, preferably 500 nm or less, and more preferably 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less. In other words, the distance between the side surface of EL layer 172R and the side surface of EL layer 172G or the distance between the side surface of EL layer 172G and the side surface of EL layer 172B has an area of ​​1 μm or less, preferably an area of ​​0.5 μm (500 nm) or less, and more preferably an area of ​​100 nm or less.

[0214] Furthermore, for example, when the region 275 contains gas, it is possible to isolate the light emitting elements while suppressing color mixing or crosstalk of the light from each light emitting element.

[0215] Note that the region 275 may be filled with, for example, an insulating layer containing an organic material. For example, an acrylic resin, a polyimide resin, an epoxy resin, a polyamide resin, a polyimideamide resin, a siloxane resin, a benzocyclobutene-based resin, a phenolic resin, or precursors of these resins may be used as the insulating layer containing an organic material. Furthermore, a photosensitive resin may be used as the material to fill the region 275. The photosensitive resin may be a positive-type material or a negative-type material.

[0216] By using a photosensitive resin, the region 275 can be formed by only the steps of exposure and development. Alternatively, the region 275 may be formed using a negative photosensitive resin. Furthermore, when an insulating layer containing an organic material is used as the region 275, it is preferable to use a material that absorbs visible light. Using a material that absorbs visible light for the region 275 allows the region 275 to absorb light emitted from the EL layer, thereby suppressing light (stray light) that may leak into an adjacent EL layer. Therefore, a display device with high display quality can be provided.

[0217] Furthermore, when the above-described white light-emitting element (single structure or tandem structure) is compared with a light-emitting element having an SBS structure, the light-emitting element having an SBS structure can reduce power consumption compared to the white light-emitting element. When it is desired to reduce power consumption, it is preferable to use a light-emitting element having an SBS structure. On the other hand, the manufacturing process of the white light-emitting element is simpler than that of the light-emitting element having an SBS structure, and therefore the manufacturing cost can be reduced or the manufacturing yield can be increased, making it preferable.

[0218] FIG. 15A shows an example different from the above. Specifically, the configuration shown in FIG. 15A differs from the configuration shown in FIG. 14D in the configuration of the insulating layer 363. The insulating layer 363 has a recess formed by removing a portion of its upper surface during processing of the light-emitting elements 161R, 161G, and 161B. Furthermore, a protective layer 271 is formed in the recess. In other words, the insulating layer 363 has a region where the lower surface of the protective layer 271 is located lower than the lower surface of the conductive layer 171 in a cross-sectional view. By having this region, impurities (typically, water, etc.) that may enter the light-emitting elements 161R, 161G, and 161B from below can be suitably suppressed. The recess can be formed when impurities (also referred to as residue) that may adhere to the side surfaces of the light-emitting elements 161R, 161G, and 161B are removed by wet etching or the like during processing of the light-emitting elements 161R, 161G, and 161B. After removing the residue, the side surfaces of the light emitting elements are covered with a protective layer 271, thereby making it possible to provide a highly reliable display device.

[0219] FIG. 15B also shows a different example. Specifically, the configuration shown in FIG. 15B includes an insulating layer 276 and a microlens array 277 in addition to the configuration shown in FIG. 15A . The insulating layer 276 functions as an adhesive layer. If the refractive index of the insulating layer 276 is lower than that of the microlens array 277, the microlens array 277 may be able to focus the light emitted from the light-emitting elements 161R, 161G, and 161B. Focusing the light emitted from the light-emitting elements 161R, 161G, and 161B is advantageous because it allows a bright image to be viewed, especially when the user views the display surface from directly in front of the display device. Note that various curing adhesives, such as a photo-curing adhesive (e.g., an ultraviolet-curing adhesive), a reactive-curing adhesive, a thermosetting adhesive, or an anaerobic adhesive, can be used as the insulating layer 276. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. Materials with low moisture permeability, such as epoxy resin, are particularly preferred. Two-component resins may also be used. For example, adhesive sheets may also be used.

[0220] FIG. 15C also shows an example different from the above. Specifically, the configuration shown in FIG. 15C has three light-emitting elements 161W instead of the light-emitting elements 161R, 161G, and 161B in the configuration shown in FIG. 15A. An insulating layer 276 is provided above the three light-emitting elements 161W, and colored layers 264R, 264G, and 264B are provided above the insulating layer 276. The colored layers may also be referred to as color filters. Specifically, a colored layer 264R that transmits red light is provided at a position overlapping the left light-emitting element 161W, a colored layer 264G that transmits green light is provided at a position overlapping the center light-emitting element 161W, and a colored layer 264B that transmits blue light is provided at a position overlapping the right light-emitting element 161W. This allows the display device to display a color image. The configuration shown in FIG. 15C is also a variation of the configuration shown in FIG. 14C.

[0221] 15C can be configured as a single structure or a tandem structure capable of emitting white light as described above. The tandem structure is preferable because it can provide high-luminance light emission.

[0222] Furthermore, by combining the above-mentioned structure capable of emitting white light (either a single structure or a tandem structure, or both), a color filter, and the MML structure of one embodiment of the present invention, a display device having a high contrast ratio can be obtained.

[0223] 15D shows an example different from the above. Specifically, in the structure shown in FIG. 15D, a protective layer 271 is provided adjacent to the side surfaces of the conductive layer 171 and the EL layer 172. The conductive layer 173 is provided as a continuous layer common to each light-emitting element. In the structure shown in FIG. 15D, it is preferable that the region 275 is filled with a filler material.

[0224] The color purity of the emitted color can be increased by providing a micro-optical resonator (microcavity) structure to the light-emitting element 161. To provide the light-emitting element 161 with a microcavity structure, the product (optical path length) of the distance d between the conductive layer 171 and the conductive layer 173 and the refractive index n of the EL layer 172 should be configured to be m times half the wavelength λ (m is an integer of 1 or greater). The distance d can be calculated using Equation 1.

[0225] d = m × λ / (2 × n)... Equation 1.

[0226] According to Equation 1, the distance d of the light emitting element 161 having the microcavity structure is determined according to the wavelength of the emitted light (emission color). The distance d corresponds to the thickness of the EL layer 172. Therefore, the EL layer 172G may be provided thicker than the EL layer 172B, and the EL layer 172R may be provided thicker than the EL layer 172G.

[0227] Strictly speaking, the distance d is the distance from the reflective region of the conductive layer 171, which functions as a reflective electrode, to the reflective region of the conductive layer 173, which functions as a semi-transmissive and semi-reflective electrode. For example, if the conductive layer 171 is a laminate of silver and ITO, which is a transparent conductive film, and the ITO is on the EL layer 172 side, the distance d can be set according to the emitted color by adjusting the film thickness of the ITO. In other words, even if the thicknesses of the EL layers 172R, 172G, and 172B are the same, the distance d appropriate for the emitted color can be obtained by changing the thickness of the ITO.

[0228] However, it may be difficult to precisely determine the positions of the reflective regions in the conductive layers 171 and 173. In this case, it is assumed that the microcavity effect can be fully obtained by assuming that any position on the conductive layers 171 and 173 is the reflective region.

[0229] The light-emitting element 161 is composed of a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, etc. In order to increase the light extraction efficiency in the microcavity structure, it is preferable to set the optical distance from the conductive layer 171, which functions as a reflective electrode, to the light-emitting layer to an odd multiple of λ / 4. To achieve this optical distance, it is preferable to appropriately adjust the thickness of each layer that constitutes the light-emitting element 161.

[0230] Furthermore, when light is emitted from the conductive layer 173 side, it is preferable that the reflectance of the conductive layer 173 is higher than the transmittance. The light transmittance of the conductive layer 173 is preferably 2% to 50%, more preferably 2% to 30%, and even more preferably 2% to 10%. By reducing the transmittance of the conductive layer 173 (increasing the reflectance), the effect of the microcavity can be enhanced.

[0231] Fig. 16A shows a perspective view of display device 35. Display device 35 shown in Fig. 16A includes layer 160 stacked on layer 150. Layer 150 includes a plurality of pixel circuits 151 arranged in a matrix, a first drive circuit unit 231, a second drive circuit unit 232, and an input / output terminal unit 129. Layer 160 includes a plurality of light-emitting elements 161 arranged in a matrix.

[0232] One pixel circuit 151 and one light-emitting element 161 are electrically connected to each other to function as one pixel 230. Therefore, a region where the plurality of pixel circuits 151 included in the layer 150 and the plurality of light-emitting elements 161 included in the layer 160 overlap functions as a display region 235.

[0233] Power, signals, and the like required for the operation of the display device 35 are supplied to the display device 35 via an input / output terminal unit 129. In the display device 35 shown in Fig. 16A, the transistors included in the peripheral driving circuit and the transistors included in the pixels 230 can be formed in the same process.

[0234] 16B , the display device 35 may be configured such that a layer 140, a layer 150, and a layer 160 are stacked one on top of the other. In FIG. 16B , a plurality of pixel circuits 151 arranged in a matrix are provided on the layer 150, and a first drive circuit unit 231 and a second drive circuit unit 232 are provided on the layer 140. By providing the first drive circuit unit 231 and the second drive circuit unit 232 on a different layer from the pixel circuits 151, the width of the frame around the display area 235 can be narrowed, and the area occupied by the display area 235 can be expanded.

[0235] By increasing the occupied area of ​​the display region 235, the resolution of the display region 235 can be increased. When the resolution of the display region 235 is constant, the occupied area per pixel can be increased. Therefore, the luminance of the display region 235 can be increased. Furthermore, the ratio of the luminous area to the occupied area of ​​one pixel (also referred to as the "aperture ratio") can be increased. For example, the pixel aperture ratio can be set to 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, by increasing the occupied area per pixel, the current density supplied to the light-emitting element 161 can be reduced. Therefore, the load on the light-emitting element 161 is reduced, and the reliability of the display device 35 can be improved. Therefore, the reliability of the mobile object 10 including the display device 35 can be improved.

[0236] Furthermore, for example, by stacking the display area 235 and the peripheral drive circuit, the wiring electrically connecting them can be shortened, thereby reducing the wiring resistance and parasitic capacitance and increasing the operating speed of the display device 35. Furthermore, the power consumption of the display device 35 can be reduced.

[0237] Furthermore, the layer 140 may include not only the peripheral drive circuit but also the CPU 123, the GPU 124, and the memory circuit unit 125. In the present embodiment and the like, the peripheral drive circuit, the CPU 123, the GPU 124, and the memory circuit unit 125 may be collectively referred to as the "functional circuit."

[0238] For example, the CPU 123 has a function of controlling the operation of the circuits provided in the layer 140 in accordance with a program stored in the memory circuit unit 125. The GPU 124 has a function of performing arithmetic processing to form image data. Furthermore, the GPU 124 can perform many matrix operations (product-sum operations) in parallel, allowing it to perform arithmetic processing using, for example, a neural network at high speed. The GPU 124 has a function of correcting image data using correction data stored in the memory circuit unit 125. For example, the GPU 124 has a function of generating image data with corrections made to brightness, color, and / or contrast, etc.

[0239] The GPU 124 may be used to upconvert or downconvert image data. A super-resolution circuit may also be provided in the layer 140. The super-resolution circuit has a function of determining the potential of any pixel in the display area 235 by multiplying and accumulating the potentials and weights of the pixels surrounding the pixel. The super-resolution circuit has a function of upconverting image data having a resolution lower than that of the display area 235. The super-resolution circuit also has a function of downconverting image data having a resolution higher than that of the display area 235.

[0240] Providing a super-resolution circuit can reduce the load on the GPU 124. For example, the GPU 124 can process up to 2K resolution (or 4K resolution), and the super-resolution circuit can upconvert to 4K resolution (or 8K resolution), thereby reducing the load on the GPU 124. Downconversion can be performed in the same manner.

[0241] The functional circuit included in the layer 140 does not need to include all of these components, or may include other components. For example, the functional circuit may include a potential generating circuit that generates a plurality of different potentials, and / or a power management circuit that controls the supply and stop of power to each circuit included in the display device 35.

[0242] The supply and stopping of power may be performed for each circuit constituting the CPU 123. For example, power supply to a circuit constituting the CPU 123 that is determined not to be used for a while may be stopped, and power supply may be resumed when necessary, thereby reducing power consumption. Data required when power supply is resumed may be stored in a memory circuit within the CPU 123 or in the memory circuit unit 125 or the like before the circuit is stopped. Storing data required when the circuit is restored enables the stopped circuit to be restored quickly. Note that circuit operation may be stopped by stopping the supply of a clock signal.

[0243] Furthermore, the functional circuits may include a DSP (Demand Side Platform) circuit, a sensor circuit, a communication circuit, and / or an FPGA (Field Programmable Gate Array).

[0244] Furthermore, some of the transistors constituting the functional circuits included in the layer 140 may be provided in the layer 150. Furthermore, some of the transistors constituting the pixel circuits 151 included in the layer 150 may be provided in the layer 140. Therefore, the functional circuits may be configured to include Si transistors and OS transistors. Furthermore, the pixel circuits 151 may be configured to include Si transistors and OS transistors.

[0245] 17 shows an example of a cross-sectional configuration of a portion of the display device 35 shown in Fig. 16A. The display device 35 shown in Fig. 17 includes a layer 150 including a substrate 301, a capacitor 246, and a transistor 310, and a layer 160 including light-emitting elements 161R, 161G, and 161B. The layer 160 is provided on an insulating layer 363 included in the layer 150.

[0246] The light emitting element 161R can emit light 175R having an intensity in at least the red wavelength range, the light emitting element 161G can emit light 175G having an intensity in at least the green wavelength range, and the light emitting element 161B can emit light 175B having an intensity in at least the blue wavelength range.

[0247] The transistor 310 is a transistor including a channel formation region in a substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as a source or drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0248] An element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0249] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 246 is provided over the insulating layer 261 .

[0250] The capacitor 246 includes a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 246, the conductive layer 245 functions as the other electrode of the capacitor 246, and the insulating layer 243 functions as a dielectric of the capacitor 246.

[0251] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 by a plug 266 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0252] An insulating layer 255 is provided to cover the capacitor 246, an insulating layer 363 is provided on the insulating layer 255, and the light-emitting elements 161R, 161G, and 161B are provided on the insulating layer 363. A protective layer 415 is provided on the light-emitting elements 161R, 161G, and 161B, and a substrate 420 is provided on the upper surface of the protective layer 415 with a resin layer 419 interposed therebetween.

[0253] The pixel electrode of the light-emitting element is electrically connected to one of the source or drain of the transistor 310 by a plug 256 embedded in the insulating layer 243, the insulating layer 255, and the insulating layer 363, a conductive layer 241 embedded in the insulating layer 254, and a plug 266 embedded in the insulating layer 261.

[0254] Fig. 18 shows a modification of the cross-sectional configuration example shown in Fig. 17. The cross-sectional configuration example of the display device 35 shown in Fig. 18 differs from the cross-sectional configuration example shown in Fig. 17 mainly in that a transistor 320 is provided instead of the transistor 310. Note that descriptions of the same parts as in Fig. 17 may be omitted.

[0255] The transistor 320 is a transistor in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0256] The transistor 320 includes a semiconductor layer 321 , an insulating layer 323 , a conductive layer 324 , a pair of conductive layers 325 , an insulating layer 326 , and a conductive layer 327 .

[0257] The substrate 331 can be an insulating substrate or a semiconductor substrate.

[0258] An insulating layer 332 is provided over a substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320 and prevents oxygen from being released from the semiconductor layer 321 toward the insulating layer 332. The insulating layer 332 can be, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0259] A conductive layer 327 is provided over the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 functions as a first gate electrode of the transistor 320, and part of the insulating layer 326 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 326 that is in contact with the semiconductor layer 321. The top surface of the insulating layer 326 is preferably planarized.

[0260] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide film having semiconductor properties.

[0261] The pair of conductive layers 325 are provided over and in contact with the semiconductor layer 321 and function as a source electrode and a drain electrode.

[0262] An insulating layer 328 is provided to cover top surfaces and side surfaces of the pair of conductive layers 325 and side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided over the insulating layer 328. The insulating layer 328 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 264 or the like to the semiconductor layer 321 and prevents oxygen from being released from the semiconductor layer 321. The insulating layer 328 can be an insulating film similar to the insulating layer 332.

[0263] Openings reaching the semiconductor layer 321 are provided in the insulating layer 328 and the insulating layer 264. Inside the openings, an insulating layer 323 and a conductive layer 324 are buried, which are in contact with side surfaces of the insulating layer 264, the insulating layer 328, and the conductive layer 325 and an upper surface of the semiconductor layer 321. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0264] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0265] The insulating layer 264 and the insulating layer 265 function as interlayer insulating layers. The insulating layer 329 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 265 or the like to the transistor 320. The insulating layer 329 can be formed using an insulating film similar to the insulating layer 328 and the insulating layer 332.

[0266] The plug 274 electrically connected to one of the pair of conductive layers 325 is provided to be embedded in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328. Here, the plug 274 preferably includes a conductive layer 274a covering the side surfaces of the openings of the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328 and part of the top surface of the conductive layer 325, and a conductive layer 274b in contact with the top surface of the conductive layer 274a. In this case, the conductive layer 274a is preferably made of a conductive material through which hydrogen and oxygen do not easily diffuse.

[0267] The display device shown in FIG. 18 has an OS transistor and a light-emitting element with an MML (metal maskless) structure. This structure can significantly reduce leakage current that may flow through the transistor and leakage current that may flow between adjacent light-emitting elements (also referred to as lateral leakage current, side leakage current, etc.). Furthermore, when an image is displayed on the display device, the viewer can observe one or more of image clarity, image sharpness, high saturation, and a high contrast ratio. By using a structure in which the leakage current that may flow through the transistor and the lateral leakage current between light-emitting elements are extremely low, a display (also referred to as true black display) with extremely low light leakage (so-called white floating) that may occur during black display can be achieved.

[0268] In particular, among light-emitting elements having an MML structure, by applying the SBS structure shown above, the layer provided between the light-emitting elements (for example, an organic layer used in common between the light-emitting elements, also called a common layer) is configured to be separated, thereby making it possible to achieve a display with no side leakage or extremely little side leakage.

[0269] 19 shows an example of a cross-sectional structure of a portion of the display device 35 shown in Fig. 16B. The display device 35 shown in Fig. 19 has a stacked structure of a transistor 310A whose channel is formed in a substrate 301A included in the layer 140 and a transistor 310B whose channel is formed in the substrate 301A included in the layer 140. The same material as that of the substrate 301 can be used for the substrate 301A.

[0270] The display device 35 shown in Figure 19 has a configuration in which a layer 160 in which a light-emitting element 161 is provided, a layer 150 in which a substrate 301B, a transistor 310B, and a capacitor 246 are provided, and a layer 140 in which a substrate 301A and a transistor 310A are provided are bonded together.

[0271] The substrate 301B is provided with a plug 343 penetrating the substrate 301B. The plug 343 functions as a through silicon electrode (TSV: Through Silicon Via). The plug 343 is also electrically connected to a conductive layer 342 provided on the back surface of the substrate 301B (the surface on the substrate 301A side). On the other hand, the substrate 301A has a conductive layer 341 provided on an insulating layer 261.

[0272] The conductive layer 341 and the conductive layer 342 are joined together, thereby electrically connecting the layer 140 and the layer 150 .

[0273] The conductive layers 341 and 342 are preferably made of the same conductive material. For example, a metal film containing an element selected from Al, Cr, Cu, Ta, Sn, Zn, Au, Ag, Pt, Ti, Mo, and W, or a metal nitride film containing the above elements (titanium nitride film, molybdenum nitride film, tungsten nitride film), etc., can be used. In particular, copper is preferably used for the conductive layers 341 and 342. This allows for the application of Cu-Cu (copper-copper) direct bonding technology (a technology for achieving electrical conductivity by connecting Cu (copper) pads together). The conductive layers 341 and 342 may also be bonded via bumps.

[0274] Fig. 20 shows a modification of the cross-sectional configuration example shown in Fig. 19. The cross-sectional configuration example of a display device 35 shown in Fig. 20 includes a stack of a transistor 310A in which a channel is formed in a substrate 301A and a transistor 320 in which a channel is formed and a semiconductor layer containing metal oxide. Note that descriptions of the same parts as those in Figs. 17 to 19 may be omitted.

[0275] The layer 150 shown in FIG. 20 has a structure in which the substrate 331 is removed from the layer 150 shown in FIG. 18 . In the layer 140 shown in FIG. 20 , an insulating layer 261 is provided to cover the transistor 310A, and a conductive layer 251 is provided over the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and the conductive layer 252 is provided over the insulating layer 262. The conductive layer 251 and the conductive layer 252 each function as wirings. An insulating layer 263 and an insulating layer 332 are provided to cover the conductive layer 252, and the transistor 320 is provided over the insulating layer 332. An insulating layer 265 is provided to cover the transistor 320, and a capacitor 246 is provided over the insulating layer 265. The capacitor 246 and the transistor 320 are electrically connected by a plug 274. The layer 150 is provided to overlap the insulating layer 263 included in the layer 140.

[0276] The transistor 320 can be used as a transistor included in the pixel circuit 151. The transistor 310 can be used as a transistor included in the pixel circuit 151 or a transistor included in a peripheral driver circuit. The transistors 310 and 320 can be used as transistors included in a functional circuit such as an arithmetic circuit or a memory circuit.

[0277] With this structure, not only the pixel circuit 151 but also, for example, a peripheral driver circuit can be formed directly under the layer 160 including the light-emitting element 161. Therefore, the display device can be made smaller than when the driver circuit is provided on the periphery of the display region.

[0278] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0279] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0280] Embodiment 3 In this embodiment, a transistor that can be used in a moving object according to one embodiment of the present invention will be described.

[0281] 21A, 21B, and 21C are a top view and a cross-sectional view of a transistor 500 that can be used in a moving object of one embodiment of the present invention. The transistor 500 can be applied to the moving object of one embodiment of the present invention.

[0282] FIG. 21A is a top view of the transistor 500. Also, FIGS. 21B and 21C are cross-sectional views of the transistor 500. Here, FIG. 21B is a cross-sectional view of a portion indicated by a dashed dotted line A1-A2 in FIG. 21A and is also a cross-sectional view of the transistor 500 in the channel length direction. Also, FIG. 21C is a cross-sectional view of a portion indicated by a dashed dotted line A3-A4 in FIG. 21A and is also a cross-sectional view of the transistor 500 in the channel width direction. Note that in the top view of FIG. 21A, some elements are omitted for clarity.

[0283] 21A to 21C , the transistor 500 includes a metal oxide 531 a disposed on a substrate (not shown), a metal oxide 531 b disposed on the metal oxide 531 a, conductive layers 542 a and 542 b disposed spaced apart from each other on the metal oxide 531 b, an insulating layer 580 disposed on the conductive layers 542 a and 542 b and having an opening formed between the conductive layers 542 a and 542 b, a conductive layer 560 disposed in the opening, an insulating layer 550 disposed among the metal oxide 531 b, the conductive layers 542 a, the conductive layers 542 b, the insulating layer 580, and the conductive layer 560, and a metal oxide 531 c disposed among the metal oxide 531 b, the conductive layers 542 a, the conductive layers 542 b, the insulating layer 580, and the insulating layer 550. 21B and 21C , the top surface of the conductive layer 560 preferably substantially coincides with the top surfaces of the insulating layer 550, the metal oxide 531c, and the insulating layer 580. Note that hereinafter, the metal oxides 531a, 531b, and 531c may be collectively referred to as the metal oxide 531. The conductive layers 542a and 542b may be collectively referred to as the conductive layer 542.

[0284] 21B and 21C , the side surfaces of the conductive layers 542a and 542b facing the conductive layer 560 have a substantially perpendicular shape. Note that the transistor 500 shown in FIGS. 21B and 21C is not limited thereto, and the angle formed between the side surface and the bottom surface of the conductive layer 542a and the conductive layer 542b may be 10° to 80°, preferably 30° to 60°. Furthermore, the opposing side surfaces of the conductive layer 542a and the conductive layer 542b may have a plurality of surfaces.

[0285] 21B and 21C, an insulating layer 554 is preferably disposed between the insulating layer 524, the metal oxide 531a, the metal oxide 531b, the conductive layer 542a, and the conductive layer 542b and the insulating layer 580. Here, the insulating layer 554 is preferably in contact with the side surface of the metal oxide 531c, the top and side surfaces of the conductive layer 542a, the top and side surfaces of the conductive layer 542b, the side surfaces of the metal oxide 531a and the metal oxide 531b, and the top surface of the insulating layer 524, as shown in FIG.

[0286] Although the transistor 500 has a three-layer structure including the metal oxide 531a, the metal oxide 531b, and the metal oxide 531c in the channel formation region and its vicinity, the present invention is not limited to this structure. For example, a two-layer structure including the metal oxide 531b and the metal oxide 531c or a stacked structure of four or more layers may be provided. Although the conductive layer 560 in the transistor 500 has a two-layer structure, the present invention is not limited to this structure. For example, the conductive layer 560 may have a single-layer structure or a stacked structure of three or more layers. Furthermore, each of the metal oxide 531a, the metal oxide 531b, and the metal oxide 531c may have a stacked structure of two or more layers.

[0287] For example, when the metal oxide 531c has a layered structure consisting of a first metal oxide and a second metal oxide on the first metal oxide, it is preferable that the first metal oxide has a composition similar to that of the metal oxide 531b, and the second metal oxide has a composition similar to that of the metal oxide 531a.

[0288] Here, the conductive layer 560 functions as a gate electrode of the transistor, and the conductive layers 542a and 542b function as a source electrode and a drain electrode, respectively. As described above, the conductive layer 560 is formed to fill the opening of the insulating layer 580 and the region sandwiched between the conductive layers 542a and 542b. Here, the conductive layers 560, 542a, and 542b are arranged in a self-aligned manner with respect to the opening of the insulating layer 580. That is, in the transistor 500, the gate electrode can be arranged between the source electrode and the drain electrode in a self-aligned manner. Therefore, the conductive layer 560 can be formed without providing a margin for alignment, thereby reducing the area occupied by the transistor 500. This enables a high-resolution display device. Furthermore, the display device can have a narrow frame.

[0289] As shown in Figures 21B and 21C, it is preferable that the conductive layer 560 has a conductive layer 560a provided inside the insulating layer 550 and a conductive layer 560b provided so as to be embedded inside the conductive layer 560a.

[0290] The transistor 500 preferably includes an insulating layer 514 disposed over a substrate (not shown), an insulating layer 516 disposed over the insulating layer 514, a conductive layer 505 disposed so as to be embedded in the insulating layer 516, an insulating layer 522 disposed over the insulating layer 516 and the conductive layer 505, and an insulating layer 524 disposed over the insulating layer 522. A metal oxide 531a is preferably disposed over the insulating layer 524.

[0291] An insulating layer 574 functioning as an interlayer film and an insulating layer 581 are preferably provided over the transistor 500. Here, the insulating layer 574 is preferably provided in contact with top surfaces of the conductive layer 560, the insulating layer 550, the metal oxide 531c, and the insulating layer 580.

[0292] The insulating layer 522, the insulating layer 554, and the insulating layer 574 preferably have a function of suppressing diffusion of hydrogen (for example, at least one of hydrogen atoms, hydrogen molecules, and the like). For example, the insulating layer 522, the insulating layer 554, and the insulating layer 574 preferably have lower hydrogen permeability than the insulating layer 524, the insulating layer 550, and the insulating layer 580. The insulating layer 522 and the insulating layer 554 preferably have a function of suppressing diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, and the like). For example, the insulating layer 522 and the insulating layer 554 preferably have lower oxygen permeability than the insulating layer 524, the insulating layer 550, and the insulating layer 580.

[0293] Here, the insulating layer 524, the metal oxide 531, and the insulating layer 550 are separated from each other by the insulating layer 580 and the insulating layer 581, and the insulating layer 554 and the insulating layer 574. Therefore, impurities such as hydrogen contained in the insulating layer 580 and the insulating layer 581 and excess oxygen can be prevented from being mixed into the insulating layer 524, the metal oxide 531, and the insulating layer 550.

[0294] A conductive layer 545 (conductive layer 545a and conductive layer 545b) electrically connected to the transistor 500 and functioning as a plug is preferably provided. Note that the insulating layer 541 (insulating layer 541a and insulating layer 541b) is provided in contact with the side surface of the conductive layer 545 functioning as a plug. That is, the insulating layer 541 is provided in contact with the inner walls of the openings of the insulating layer 554, the insulating layer 580, the insulating layer 574, and the insulating layer 581. Alternatively, a first conductive layer of the conductive layer 545 may be provided in contact with the side surface of the insulating layer 541, and a second conductive layer of the conductive layer 545 may be provided further inside. Here, the height of the top surface of the conductive layer 545 and the height of the top surface of the insulating layer 581 can be made approximately the same. Note that the transistor 500 illustrates a structure in which the first conductive layer of the conductive layer 545 and the second conductive layer of the conductive layer 545 are stacked, but the present invention is not limited to this. For example, the conductive layer 545 may be provided as a single layer or a stacked structure of three or more layers. When the structure has a stacked structure, the layers may be distinguished by adding ordinal numbers to the order of formation.

[0295] In the transistor 500, a metal oxide that functions as an oxide semiconductor is preferably used for the metal oxide 531 (the metal oxide 531a, the metal oxide 531b, and the metal oxide 531c) including the channel formation region. For example, a metal oxide that serves as the channel formation region of the metal oxide 531 preferably has a band gap of 2 eV or more, preferably 2.5 eV or more.

[0296] The metal oxide preferably contains at least indium (In) or zinc (Zn). In particular, it is preferable that it contains indium (In) and zinc (Zn). In addition to these, it is preferable that it contains element M. As element M, one or more of aluminum (Al), gallium (Ga), yttrium (Y), tin (Sn), boron (B), titanium (Ti), iron (Fe), nickel (Ni), germanium (Ge), zirconium (Zr), molybdenum (Mo), lanthanum (La), cerium (Ce), neodymium (Nd), hafnium (Hf), tantalum (Ta), tungsten (W), magnesium (Mg), or cobalt (Co) can be used. In particular, element M is preferably one or more of aluminum (Al), gallium (Ga), yttrium (Y), or tin (Sn). Furthermore, it is more preferable that element M contains either one or both of Ga and Sn.

[0297] 21B , the thickness of the metal oxide 531b in a region that does not overlap with the conductive layer 542 may be thinner than the thickness of the region that overlaps with the conductive layer 542. This is formed by removing part of the top surface of the metal oxide 531b when forming the conductive layers 542a and 542b. When a conductive film that will become the conductive layer 542 is formed on the top surface of the metal oxide 531b, a low-resistance region may be formed near the interface with the conductive film. In this way, removing the low-resistance region located between the conductive layers 542a and 542b on the top surface of the metal oxide 531b can prevent a channel from being formed in the region.

[0298] According to one embodiment of the present invention, a display device having high definition and a small transistor can be provided. Alternatively, a display device having high luminance and a transistor with high on-state current can be provided. Alternatively, a display device having high-speed operation and a transistor with stable electrical characteristics can be provided. Alternatively, a display device having low power consumption and a transistor with low off-state current can be provided.

[0299] The detailed structure of the transistor 500 that can be used in a moving object of one embodiment of the present invention will be described.

[0300] The conductive layer 505 is arranged to have a region overlapping with the metal oxide 531 and the conductive layer 560. The conductive layer 505 is preferably embedded in the insulating layer 516.

[0301] The conductive layer 505 includes a conductive layer 505a, a conductive layer 505b, and a conductive layer 505c. The conductive layer 505a is provided in contact with the bottom surface and sidewalls of an opening provided in the insulating layer 516. The conductive layer 505b is provided so as to fill a recess formed in the conductive layer 505a. The top surface of the conductive layer 505b is lower than the top surfaces of the conductive layer 505a and the insulating layer 516. The conductive layer 505c is provided in contact with the top surface of the conductive layer 505b and the side surface of the conductive layer 505a. The height of the top surface of the conductive layer 505c is approximately the same as the height of the top surface of the conductive layer 505a and the top surface of the insulating layer 516. In other words, the conductive layer 505b is surrounded by the conductive layers 505a and 505c.

[0302] The conductive layer 505a and the conductive layer 505c are formed of hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules (N ２ O, NO, NO ２ It is preferable to use a conductive material that has a function of suppressing the diffusion of impurities such as copper atoms, etc. Alternatively, it is preferable to use a conductive material that has a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.).

[0303] By using a conductive material that can reduce hydrogen diffusion for the conductive layers 505a and 505c, impurities such as hydrogen contained in the conductive layer 505b can be prevented from diffusing into the metal oxide 531 through the insulating layer 524 or the like. Furthermore, by using a conductive material that can reduce oxygen diffusion for the conductive layers 505a and 505c, oxidation of the conductive layer 505b and a decrease in conductivity can be prevented. Examples of conductive materials that can reduce oxygen diffusion include titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, and ruthenium oxide. Therefore, the conductive layer 505a may be formed as a single layer or a stack of any of the above conductive materials. For example, titanium nitride may be used for the conductive layer 505a.

[0304] The conductive layer 505b is preferably formed using a conductive material containing tungsten, copper, or aluminum as a main component, for example, tungsten.

[0305] Here, the conductive layer 560 may function as a first gate (also referred to as a top gate) electrode. The conductive layer 505 may function as a second gate (also referred to as a bottom gate) electrode. In this case, the V of the transistor 500 can be controlled by changing the potential applied to the conductive layer 505 independently of the potential applied to the conductive layer 560. ｔｈ In particular, by applying a negative potential to the conductive layer 505, the V ｔｈ Therefore, when a negative potential is applied to the conductive layer 505, the drain current when the potential applied to the conductive layer 560 is 0 V can be made smaller than when no negative potential is applied.

[0306] The conductive layer 505 is preferably larger than the channel formation region of the metal oxide 531. In particular, as shown in Fig. 21C, the conductive layer 505 preferably extends also in a region outside the end portion intersecting with the channel width direction of the metal oxide 531. That is, outside the side surface of the metal oxide 531 in the channel width direction, the conductive layer 505 and the conductive layer 560 preferably overlap with each other with an insulating layer interposed therebetween.

[0307] With the above structure, the channel formation region of the metal oxide 531 can be electrically surrounded by the electric field of the conductive layer 560 functioning as a first gate electrode and the electric field of the conductive layer 505 functioning as a second gate electrode.

[0308] 21C, the conductive layer 505 is extended to function as a wiring. However, the present invention is not limited to this, and a conductive layer functioning as a wiring may be provided below the conductive layer 505.

[0309] The insulating layer 514 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the transistor 500 from the substrate side. Therefore, the insulating layer 514 is resistant to hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules (N ２ O, NO, or NO ２ It is preferable to use an insulating material that has a function of suppressing the diffusion of impurities such as copper atoms (e.g., copper atoms, copper molecules, etc.) or copper atoms (i.e., the impurities are less likely to permeate through the insulating material). It is also preferable to use an insulating material that has a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.) (i.e., the oxygen is less likely to permeate through the insulating material).

[0310] For example, aluminum oxide, silicon nitride, or the like is preferably used for the insulating layer 514. This can prevent impurities such as water or hydrogen from diffusing from the substrate side of the insulating layer 514 to the transistor 500 side. Alternatively, it can prevent oxygen contained in the insulating layer 524 or the like from diffusing to the substrate side of the insulating layer 514.

[0311] The insulating layer 516, the insulating layer 580, and the insulating layer 581, which function as interlayer films, preferably have a lower dielectric constant than the insulating layer 514. By using a material with a low dielectric constant as the interlayer film, parasitic capacitance generated between wirings can be reduced. For example, the insulating layer 516, the insulating layer 580, and the insulating layer 581 may be formed using silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide to which fluorine has been added, silicon oxide to which carbon has been added, silicon oxide to which carbon and nitrogen have been added, silicon oxide having vacancies, or the like as appropriate.

[0312] The insulating layers 522 and 524 function as gate insulating layers.

[0313] Here, the insulating layer 524 in contact with the metal oxide 531 preferably releases oxygen by heating. In this specification, oxygen released by heating is sometimes referred to as excess oxygen. For example, the insulating layer 524 may be formed using silicon oxide, silicon oxynitride, or the like as appropriate. By providing an insulating layer containing oxygen in contact with the metal oxide 531, oxygen vacancies in the metal oxide 531 can be reduced, and the reliability of the transistor 500 can be improved.

[0314] Specifically, an oxide material from which part of oxygen is released by heating is preferably used for the insulating layer 524. The oxide from which oxygen is released by heating is an oxide whose amount of released oxygen, converted into oxygen atoms, is 1.0×10 in thermal desorption spectroscopy (TDS) analysis. １８ atoms / cm ３ or more, preferably 1.0 × 10 １９ atoms / cm ３ More preferably, 2.0 × 10 １９ atoms / cm ３ or more, or 3.0 x 10 ２０ atoms / cm ３ The surface temperature of the film during the TDS analysis is preferably in the range of 100°C or higher and 700°C or lower, or 100°C or higher and 400°C or lower.

[0315] 21C , the thickness of the insulating layer 524 in a region that does not overlap with the insulating layer 554 and the metal oxide 531b may be thinner than the thickness of the other region. The thickness of the insulating layer 524 in a region that does not overlap with the insulating layer 554 and the metal oxide 531b is preferably a thickness that allows sufficient diffusion of the oxygen.

[0316] Like the insulating layer 514 and the like, the insulating layer 522 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the transistor 500 from the substrate side. For example, the insulating layer 522 preferably has lower hydrogen permeability than the insulating layer 524. By surrounding the insulating layer 524, the metal oxide 531, the insulating layer 550, and the like with the insulating layer 522, the insulating layer 554, and the insulating layer 574, impurities such as water or hydrogen can be prevented from entering the transistor 500 from the outside.

[0317] Furthermore, the insulating layer 522 preferably has a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms and oxygen molecules) (i.e., the oxygen is less likely to permeate). For example, the insulating layer 522 preferably has lower oxygen permeability than the insulating layer 524. The insulating layer 522 preferably has a function of suppressing the diffusion of oxygen and impurities, which can reduce the diffusion of oxygen contained in the metal oxide 531 toward the substrate. Furthermore, the conductive layer 505 can be prevented from reacting with oxygen contained in the insulating layer 524 and the metal oxide 531.

[0318] The insulating layer 522 may be an insulating layer containing an oxide of one or both of aluminum and hafnium, which are insulating materials. Aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), or the like is preferably used as the insulating layer containing an oxide of one or both of aluminum and hafnium. When the insulating layer 522 is formed using such a material, the insulating layer 522 functions as a layer that suppresses release of oxygen from the metal oxide 531 and the intrusion of impurities such as hydrogen into the metal oxide 531 from the periphery of the transistor 500.

[0319] 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 these insulating layers. Alternatively, these insulating layers may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be stacked on the above insulating layers.

[0320] The insulating layer 522 may be made of, for example, aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), or strontium titanate (SrTiO ３ ) or (Ba,Sr)TiO ３ An insulating layer containing a so-called high-k material such as BST may be used as a single layer or a laminate. As transistors become smaller and more highly integrated, problems such as leakage current may occur due to the thinning of the gate insulating layer. By using a high-k material for the insulating layer that functions as the gate insulating layer, it is possible to reduce the gate potential during transistor operation while maintaining the physical film thickness.

[0321] Note that the insulating layer 522 and the insulating layer 524 may have a stacked structure of two or more layers. In this case, the insulating layer 522 and the insulating layer 524 are not limited to a stacked structure made of the same material, and may have a stacked structure made of different materials. For example, an insulating layer similar to the insulating layer 524 may be provided under the insulating layer 522.

[0322] The metal oxide 531 includes a metal oxide 531a, a metal oxide 531b on the metal oxide 531a, and a metal oxide 531c on the metal oxide 531b. Having the metal oxide 531a below the metal oxide 531b can suppress the diffusion of impurities from structures formed below the metal oxide 531a to the metal oxide 531b. Having the metal oxide 531c on the metal oxide 531b can suppress the diffusion of impurities from structures formed above the metal oxide 531c to the metal oxide 531b.

[0323] The metal oxide 531 preferably has a stacked structure of multiple oxide layers with different atomic ratios of the metal atoms. For example, when the metal oxide 531 contains at least indium (In) and the element M, the ratio of the number of atoms of the element M contained in the metal oxide 531a to the number of atoms of all elements constituting the metal oxide 531a is preferably higher than the ratio of the number of atoms of the element M contained in the metal oxide 531b to the number of atoms of all elements constituting the metal oxide 531b. Furthermore, the atomic ratio of the element M contained in the metal oxide 531a to In is preferably higher than the atomic ratio of the element M contained in the metal oxide 531b to In. Here, the metal oxide 531c can be the same as the metal oxide 531a or the metal oxide 531b.

[0324] The energy of the conduction band minimum of the metal oxide 531a and the metal oxide 531c is preferably higher than the energy of the conduction band minimum of the metal oxide 531b. In other words, the electron affinity of the metal oxide 531a and the metal oxide 531c is preferably lower than the electron affinity of the metal oxide 531b. In this case, the metal oxide 531c is preferably a metal oxide that can be used for the metal oxide 531a. Specifically, the ratio of the number of atoms of the element M contained in the metal oxide 531c to the number of atoms of all elements constituting the metal oxide 531c is preferably higher than the ratio of the number of atoms of the element M contained in the metal oxide 531b to the number of atoms of all elements constituting the metal oxide 531b. Furthermore, the atomic ratio of the element M contained in the metal oxide 531c to In is preferably higher than the atomic ratio of the element M contained in the metal oxide 531b to In.

[0325] Here, the energy level of the conduction band minimum changes smoothly at the junction between the metal oxides 531a, 531b, and 531c. In other words, the energy level of the conduction band minimum at the junction between the metal oxides 531a, 531b, and 531c changes continuously or forms a continuous junction. To achieve this, it is advisable to reduce the defect level density of the mixed layers formed at the interface between the metal oxides 531a and 531b and at the interface between the metal oxides 531b and 531c.

[0326] Specifically, the metal oxide 531a and the metal oxide 531b, and the metal oxide 531b and the metal oxide 531c, have a common element other than oxygen (as a main component), thereby forming a mixed layer with a low density of defect levels. For example, when the metal oxide 531b is an In—Ga—Zn oxide, the metal oxide 531a and the metal oxide 531c may be made of an In—Ga—Zn oxide, a Ga—Zn oxide, gallium oxide, or the like. The metal oxide 531c may also have a stacked structure. For example, a stacked structure of an In—Ga—Zn oxide and a Ga—Zn oxide on the In—Ga—Zn oxide, or a stacked structure of an In—Ga—Zn oxide and a gallium oxide on the In—Ga—Zn oxide, may be used. In other words, a stacked structure of an In—Ga—Zn oxide and an oxide not containing In may be used as the metal oxide 531c.

[0327] Specifically, the metal oxide 531a may have an atomic ratio of In:Ga:Zn=1:3:4 or 1:1:0.5. The metal oxide 531b may have an atomic ratio of In:Ga:Zn=4:2:3 or 3:1:2. The metal oxide 531c may have 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. Specific examples of the metal oxide 531c having a stacked structure include 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], and a stacked structure of In:Ga:Zn=4:2:3 [atomic ratio] and gallium oxide.

[0328] In this case, the main carrier path is the metal oxide 531b. By configuring the metal oxide 531a and the metal oxide 531c as described above, the defect state density at the interface between the metal oxide 531a and the metal oxide 531b and at the interface between the metal oxide 531b and the metal oxide 531c can be reduced. This reduces the effect of interface scattering on carrier conduction, allowing the transistor 500 to achieve a high on-state current and high frequency characteristics. Note that when the metal oxide 531c has a stacked structure, in addition to the effect of reducing the defect state density at the interface between the metal oxide 531b and the metal oxide 531c, it is expected that the diffusion of constituent elements of the metal oxide 531c toward the insulating layer 550 can be suppressed. More specifically, since the metal oxide 531c has a stacked structure and an oxide not containing In is located above the stacked structure, In, which may diffuse toward the insulating layer 550, can be suppressed. The insulating layer 550 functions as a gate insulating layer, and diffusion of In leads to poor transistor characteristics. Therefore, by forming the metal oxide 531c into a layered structure, it is possible to provide a highly reliable moving body.

[0329] Conductive layers 542 (conductive layers 542a and 542b) functioning as a source electrode and a drain electrode are provided over the metal oxide 531b. For the conductive layer 542, 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 any of the above metal elements, an alloy combining any of the above metal elements, or the like, 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, or the like is preferably used. In addition, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are preferred because they are conductive materials that are resistant to oxidation or materials that maintain conductivity even when they absorb oxygen.

[0330] By providing the conductive layer 542 in contact with the metal oxide 531, the oxygen concentration may be reduced in the vicinity of the conductive layer 542 of the metal oxide 531. Furthermore, a metal compound layer containing a metal contained in the conductive layer 542 and a component of the metal oxide 531 may be formed in the vicinity of the conductive layer 542 of the metal oxide 531. In such a case, the carrier density increases in a region of the metal oxide 531 in the vicinity of the conductive layer 542, and the region becomes a low-resistance region.

[0331] Here, the region between the conductive layer 542a and the conductive layer 542b is formed to overlap the opening of the insulating layer 580. This allows the conductive layer 560 to be disposed in a self-aligned manner between the conductive layer 542a and the conductive layer 542b.

[0332] The insulating layer 550 functions as a gate insulating layer. The insulating layer 550 is preferably disposed in contact with the top surface of the metal oxide 531c. The insulating layer 550 can be formed using silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide to which fluorine has been added, silicon oxide to which carbon has been added, silicon oxide to which carbon and nitrogen have been added, or silicon oxide having vacancies. In particular, silicon oxide and silicon oxynitride are preferable because they are stable to heat.

[0333] The insulating layer 550 preferably has a reduced concentration of impurities such as water or hydrogen, similar to the insulating layer 524. The thickness of the insulating layer 550 is preferably greater than or equal to 1 nm and less than or equal to 20 nm.

[0334] A metal oxide may be provided between the insulating layer 550 and the conductive layer 560. The metal oxide preferably suppresses oxygen diffusion from the insulating layer 550 to the conductive layer 560. This can suppress oxidation of the conductive layer 560 due to oxygen in the insulating layer 550.

[0335] The metal oxide may function as part of the gate insulating layer. Therefore, when silicon oxide, silicon oxynitride, or the like is used for the insulating layer 550, the metal oxide is preferably a high-k material with a high dielectric constant. By forming the gate insulating layer with a stacked structure of the insulating layer 550 and the metal oxide, a stacked structure that is stable against heat and has a high dielectric constant can be obtained. Therefore, it is possible to reduce the gate potential applied during transistor operation while maintaining the physical thickness of the gate insulating layer. In addition, it is possible to reduce the equivalent oxide thickness (EOT) of the insulating layer that functions as the gate insulating layer.

[0336] Specifically, it is possible to use a metal oxide containing one or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, magnesium, etc. In particular, it is preferable to use an insulating layer containing an oxide of either or both of aluminum and hafnium, such as aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate).

[0337] Although the conductive layer 560 is shown as having a two-layer structure in FIGS. 21B and 21C, it may have a single-layer structure or a stacked structure of three or more layers.

[0338] The conductive layer 560a is formed of the above-mentioned hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules (N ２ O, NO, or NO ２ It is preferable to use a conductive layer having a function of suppressing the diffusion of impurities such as copper atoms or copper atoms, or a conductive material having a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.).

[0339] The conductive layer 560a has a function of suppressing oxygen diffusion, which can suppress a decrease in conductivity due to oxidation of the conductive layer 560b caused by oxygen contained in the insulating layer 550. As a conductive material having a function of suppressing oxygen diffusion, for example, tantalum, tantalum nitride, ruthenium, ruthenium oxide, or the like is preferably used.

[0340] The conductive layer 560b is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. Furthermore, since the conductive layer 560 also functions as a wiring, it is preferable to use a conductive layer with high conductivity. For example, a conductive material containing tungsten, copper, or aluminum as a main component can be used. Furthermore, the conductive layer 560b may have a layered structure, for example, a layered structure of titanium or titanium nitride and the above-mentioned conductive material.

[0341] 21A and 21C , in a region of the metal oxide 531b that does not overlap with the conductive layer 542, in other words, in a channel formation region of the metal oxide 531, the side surface of the metal oxide 531 is arranged to be covered with the conductive layer 560. This makes it easier for the electric field of the conductive layer 560, which functions as the first gate electrode, to act on the side surface of the metal oxide 531. Therefore, the on-state current of the transistor 500 can be increased, and the frequency characteristics can be improved.

[0342] Like the insulating layer 514, the insulating layer 554 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the transistor 500 from the insulating layer 580 side. For example, the insulating layer 554 preferably has lower hydrogen permeability than the insulating layer 524. Furthermore, as shown in FIGS. 21B and 21C , the insulating layer 554 preferably contacts the side surfaces of the metal oxide 531c, the top and side surfaces of the conductive layer 542a, the top and side surfaces of the conductive layer 542b, the side surfaces of the metal oxide 531a and the metal oxide 531b, and the top surface of the insulating layer 524. With this structure, hydrogen contained in the insulating layer 580 can be prevented from entering the metal oxide 531 from the top surfaces or side surfaces of the conductive layer 542a, the conductive layer 542b, the metal oxide 531a, the metal oxide 531b, and the insulating layer 524.

[0343] Furthermore, the insulating layer 554 preferably has a function of suppressing diffusion of oxygen (for example, at least one of oxygen atoms and oxygen molecules) (i.e., the insulating layer 554 is less likely to transmit oxygen). For example, the insulating layer 554 preferably has lower oxygen permeability than the insulating layer 580 or the insulating layer 524.

[0344] The insulating layer 554 is preferably formed by a sputtering method. By forming the insulating layer 554 by a sputtering method in an oxygen-containing atmosphere, oxygen can be added to the insulating layer 524 near a region in contact with the insulating layer 554. This allows oxygen to be supplied from this region to the metal oxide 531 through the insulating layer 524. Here, the insulating layer 554 has a function of suppressing upward oxygen diffusion, thereby preventing oxygen from diffusing from the metal oxide 531 to the insulating layer 580. Furthermore, the insulating layer 522 has a function of suppressing downward oxygen diffusion, thereby preventing oxygen from diffusing from the metal oxide 531 toward the substrate. In this manner, oxygen is supplied to the channel formation region of the metal oxide 531. This reduces oxygen vacancies in the metal oxide 531, and suppresses the transistor from becoming normally on.

[0345] For example, an insulating layer containing an oxide of one or both of aluminum and hafnium may be formed as the insulating layer 554. Note that as the insulating layer containing an oxide of one or both of aluminum and hafnium, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), or the like is preferably used.

[0346] The insulating layer 524, the insulating layer 550, and the metal oxide 531 are covered with the insulating layer 554 having a barrier property against hydrogen, and thus the insulating layer 580 is separated from the insulating layer 524, the metal oxide 531, and the insulating layer 550 by the insulating layer 554. This can prevent impurities such as hydrogen from entering the transistor 500 from the outside, thereby providing the transistor 500 with favorable electrical characteristics and reliability.

[0347] The insulating layer 580 is provided over the insulating layer 524, the metal oxide 531, and the conductive layer 542 with the insulating layer 554 interposed therebetween. For example, the insulating layer 580 preferably includes 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, silicon oxide having vacancies, or the like. In particular, silicon oxide and silicon oxynitride are preferable because they are thermally stable. In particular, materials such as silicon oxide, silicon oxynitride, and silicon oxide having vacancies are preferable because they can easily form a region containing oxygen that is released by heating.

[0348] The concentration of impurities such as water or hydrogen is preferably reduced in the insulating layer 580. The top surface of the insulating layer 580 may be planarized.

[0349] Similar to the insulating layer 514, the insulating layer 574 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the insulating layer 580 from above. As the insulating layer 574, for example, an insulating layer that can be used for the insulating layer 514, the insulating layer 554, or the like may be used.

[0350] An insulating layer 581 functioning as an interlayer film is preferably provided over the insulating layer 574. Like the insulating layer 524 and the like, the insulating layer 581 preferably has a reduced concentration of impurities such as water or hydrogen.

[0351] The conductive layers 545a and 545b are disposed in openings formed in the insulating layer 581, the insulating layer 574, the insulating layer 580, and the insulating layer 554. The conductive layers 545a and 545b are provided opposite to each other with the conductive layer 560 interposed therebetween. Note that the height of the top surfaces of the conductive layers 545a and 545b may be flush with the top surface of the insulating layer 581.

[0352] Note that an insulating layer 541a is provided in contact with the inner walls of the openings of the insulating layer 581, the insulating layer 574, the insulating layer 580, and the insulating layer 554, and a first conductive layer of the conductive layer 545a is formed in contact with the side surface of the insulating layer 541a. A conductive layer 542a is located in at least a part of the bottom of the opening, and the conductive layer 545a is in contact with the conductive layer 542a. Similarly, an insulating layer 541b is provided in contact with the inner walls of the openings of the insulating layer 581, the insulating layer 574, the insulating layer 580, and the insulating layer 554, and a first conductive layer of the conductive layer 545b is formed in contact with the side surface of the insulating layer 541b. A conductive layer 542b is located in at least a part of the bottom of the opening, and the conductive layer 545b is in contact with the conductive layer 542b.

[0353] The conductive layers 545a and 545b are preferably formed using a conductive material containing tungsten, copper, or aluminum as a main component. The conductive layers 545a and 545b may have a stacked structure.

[0354] When the conductive layer 545 has a stacked structure, the conductive layer having the function of suppressing the diffusion of impurities such as water or hydrogen is preferably used for the conductive layer in contact with the metal oxide 531a, the metal oxide 531b, the conductive layer 542, the insulating layer 554, the insulating layer 580, the insulating layer 574, and the insulating layer 581. For example, tantalum, tantalum nitride, titanium, titanium nitride, ruthenium, ruthenium oxide, or the like is preferably used. Furthermore, a conductive material having the function of suppressing the diffusion of impurities such as water or hydrogen may be used in a single layer or a stacked layer. The use of such a conductive material can suppress the absorption of oxygen added to the insulating layer 580 by the conductive layers 545a and 545b. Furthermore, impurities such as water or hydrogen from above the insulating layer 581 can be prevented from entering the metal oxide 531 through the conductive layers 545a and 545b.

[0355] The insulating layers 541a and 541b may be, for example, insulating layers that can be used for the insulating layer 554. The insulating layers 541a and 541b are provided in contact with the insulating layer 554, and therefore can prevent impurities such as water or hydrogen from the insulating layer 580 or the like from being mixed into the metal oxide 531 through the conductive layers 545a and 545b. Furthermore, oxygen contained in the insulating layer 580 can be prevented from being absorbed by the conductive layers 545a and 545b.

[0356] Although not shown, a conductive layer functioning as a wiring may be disposed in contact with the top surface of the conductive layer 545a and the top surface of the conductive layer 545b. The conductive layer functioning as a wiring is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. The conductive layer may have a stacked structure, for example, a stack of titanium or titanium nitride and the above-mentioned conductive material. The conductive layer may be formed so as to be embedded in an opening provided in the insulating layer.

[0357] <Constituent Materials of Transistor> Constituent materials that can be used for the transistor will be described.

[0358] [Substrate] The substrate on which the transistor 500 is formed may be, for example, an insulating substrate, a semiconductor substrate, or a conductive substrate. Examples of insulating substrates include a glass substrate, a quartz substrate, a sapphire substrate, a stabilized zirconia substrate (e.g., an yttria-stabilized zirconia substrate), or a resin substrate. Examples of semiconductor substrates include semiconductor substrates such as silicon or germanium, or compound semiconductor substrates made of silicon carbide, silicon germanium, gallium arsenide, indium phosphide, zinc oxide, or gallium oxide. Examples of semiconductor substrates include those having an insulating layer region within the semiconductor substrate, such as an SOI (Silicon-On-Insulator) substrate. Examples of conductive substrates include graphite substrates, metal substrates, alloy substrates, and conductive resin substrates. Examples of substrates include substrates having a metal nitride or a metal oxide. Examples of other substrates include a substrate having a conductive layer or a semiconductor layer provided on an insulating substrate, a substrate having a conductive layer or an insulating layer provided on a semiconductor substrate, and a substrate having a semiconductor layer or an insulating layer provided on a conductive substrate. Alternatively, a substrate provided with elements may be used. The elements provided on the substrate include a capacitor element, a resistor element, a switch element, a light-emitting element, a memory element, and the like.

[0359] [Insulating Layer] The insulating layer may be made of an insulating oxide, nitride, oxynitride, nitride oxide, metal oxide, metal oxynitride, or metal nitride oxide.

[0360] For example, as transistors become more miniaturized and highly integrated, problems such as leakage current may occur due to thinner gate insulating layers. Using a high-k material for the insulating layer that functions as the gate insulating layer allows for lower voltages during transistor operation while maintaining the physical film thickness. On the other hand, using a material with a low dielectric constant for the insulating layer that functions as the interlayer film can reduce the parasitic capacitance that occurs between wiring. Therefore, it is advisable to select materials according to the function of the insulating layer.

[0361] Examples of insulating layers with a high relative dielectric constant include 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, and nitrides containing silicon and hafnium.

[0362] Examples of insulating layers with a low dielectric constant include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide with fluorine added, silicon oxide with carbon added, silicon oxide with carbon and nitrogen added, silicon oxide with voids, or resin.

[0363] A transistor including an oxide semiconductor can have stable electrical characteristics by being surrounded by insulating layers (such as the insulating layer 514, the insulating layer 522, the insulating layer 554, and the insulating layer 574) that have a function of suppressing the permeation of impurities such as hydrogen and oxygen. As the insulating layer that has a function of suppressing the permeation of impurities such as hydrogen and oxygen, for example, a single insulating layer or a stacked insulating layer containing boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum, neodymium, hafnium, or tantalum can be used. Specifically, as the insulating layer that has a function of suppressing the permeation of impurities such as hydrogen and oxygen, a metal oxide such as aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, or tantalum oxide, or a metal nitride such as aluminum nitride, aluminum titanium nitride, titanium nitride, silicon nitride oxide, or silicon nitride can be used.

[0364] The insulating layer functioning as the gate insulating layer is preferably an insulating layer having a region containing oxygen that is released by heating. For example, by using 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 531, oxygen vacancies in the metal oxide 531 can be compensated for.

[0365] [Conductive Layer] For the conductive layer, it is preferable 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, or an alloy containing the above metal elements as a component, or an alloy combining the above metal elements. For example, it is preferable to use tantalum nitride, titanium nitride, tungsten, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, or oxides containing lanthanum and nickel. Furthermore, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are preferred because they are conductive materials that are resistant to oxidation or maintain conductivity even when absorbing oxygen. Alternatively, a semiconductor having high electrical conductivity, such as polycrystalline silicon containing an impurity element such as phosphorus, may be used, or a silicide such as nickel silicide may be used.

[0366] A plurality of conductive layers formed from the above materials may be stacked. For example, a stacked structure may be formed by combining the above-described material containing a metal element and a conductive material containing oxygen. A stacked structure may also be formed by combining the above-described material containing a metal element and a conductive material containing nitrogen. A stacked structure may also be formed by combining the above-described material containing a metal element, a conductive material containing oxygen, and a conductive material containing nitrogen.

[0367] When a metal oxide is used for the channel formation region of a transistor, the conductive layer that functions as a gate electrode preferably has a stacked structure that combines a material containing the metal element and a conductive material containing oxygen. In this case, the conductive material containing oxygen is preferably provided on the channel formation region side. By providing the conductive material containing oxygen on the channel formation region side, oxygen released from the conductive material is easily supplied to the channel formation region.

[0368] In particular, for the conductive layer functioning as a gate electrode, it is preferable to use a conductive material containing oxygen and a metal element contained in the metal oxide in which a channel is formed. Alternatively, the conductive material containing the above-mentioned metal element and nitrogen may be used. For example, a conductive material containing nitrogen, such as titanium nitride or tantalum nitride, may be used. Alternatively, 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, or indium tin oxide to which silicon is added may be used. Furthermore, indium gallium zinc oxide containing nitrogen may be used. By using such a material, hydrogen contained in the metal oxide in which a channel is formed may be captured. Alternatively, hydrogen mixed in from an outer insulating layer or the like may be captured.

[0369] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0370] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0371] Embodiment 4 In this embodiment, a metal oxide that can be used for the OS transistor described in the above embodiment will be described.

[0372] <Classification of Crystal Structures> First, classification of crystal structures in oxide semiconductors will be described with reference to Fig. 22A. Fig. 22A is a diagram illustrating classification of crystal structures of oxide semiconductors, typically IGZO (metal oxide containing In, Ga, and Zn).

[0373] As shown in FIG. 22A , oxide semiconductors are broadly classified into "amorphous," "crystalline," and "crystal." Furthermore, "amorphous" includes completely amorphous. Furthermore, "crystalline" includes c-axis-aligned crystalline (CAAC), nanocrystalline (nc), and cloud-aligned composite (CAC). The "crystalline" classification excludes single crystal, polycrystalline, and completely amorphous. Furthermore, "Crystal" includes single crystal and poly crystal.

[0374] The structure within the bold frame shown in Figure 22A is an intermediate state between "Amorphous" and "Crystal" and belongs to a new boundary region (New crystalline phase). In other words, this structure can be described as a structure that is completely different from "Crystal" or the energetically unstable "Amorphous."

[0375] The crystalline structure of the film or substrate can be evaluated using an X-ray diffraction (XRD) spectrum. Here, FIG. 22B shows an XRD spectrum obtained by GIXD (Grazing-Incidence XRD) measurement of a CAAC-IGZO film classified as "Crystalline." In FIG. 22B, the horizontal axis represents 2θ [deg.] and the vertical axis represents Intensity [a.u.]. The GIXD method is also called the thin film method or the Seemann-Bohlin method. Hereinafter, the XRD spectrum obtained by GIXD measurement shown in FIG. 22B will be simply referred to as the XRD spectrum. The composition of the CAAC-IGZO film shown in FIG. 22B is approximately In:Ga:Zn = 4:2:3 [atomic ratio]. The thickness of the CAAC-IGZO film shown in FIG. 22B is 500 nm.

[0376] As shown in Figure 22B, a peak indicating clear crystallinity is detected in the XRD spectrum of the CAAC-IGZO film. Specifically, a peak indicating c-axis orientation is detected near 2θ = 31° in the XRD spectrum of the CAAC-IGZO film. Note that, as shown in Figure 22B, the peak near 2θ = 31° is asymmetric with respect to the angle at which the peak intensity is detected.

[0377] The crystalline structure of the film or substrate can be evaluated by a diffraction pattern (also referred to as a nanobeam electron diffraction pattern) observed by nanobeam electron diffraction (NBED). The diffraction pattern of the CAAC-IGZO film is shown in FIG. 22C. FIG. 22C is a diffraction pattern observed by NBED, in which an electron beam is incident parallel to the substrate. The composition of the CAAC-IGZO film shown in FIG. 22C is near In:Ga:Zn = 4:2:3 [atomic ratio]. In the nanobeam electron diffraction method, electron beam diffraction is performed using a probe diameter of 1 nm.

[0378] As shown in FIG. 22C, multiple spots indicating c-axis orientation are observed in the diffraction pattern of the CAAC-IGZO film.

[0379] [Structure of Oxide Semiconductor] Note that oxide semiconductors may be classified differently from those shown in FIG. 22A when focusing on their crystal structures. For example, oxide semiconductors are classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, pseudo-amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0380] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0381] [CAAC-OS] A CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction refers to the thickness direction of the CAAC-OS film, the normal direction to the surface where the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region having periodic atomic arrangement. If the atomic arrangement is considered as a lattice arrangement, a crystalline region is also a region with a uniform lattice arrangement. Furthermore, a CAAC-OS has a region where multiple crystalline regions are connected in the a-b plane direction, and the region may have distortion. Note that distortion refers to a portion where the lattice arrangement changes between a region with a uniform lattice arrangement and a region with another uniform lattice arrangement in a region where multiple crystalline regions are connected. In other words, a CAAC-OS is an oxide semiconductor whose c-axes are aligned and whose orientation is not clearly aligned in the a-b plane direction.

[0382] Each of the multiple crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be several tens of nanometers.

[0383] In an In-M-Zn oxide (wherein the element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, and the like), the CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter referred to as an In layer) and a layer containing the element M, zinc (Zn), and oxygen (hereinafter referred to as an (M, Zn) layer) are stacked. Note that indium and the element M are mutually substituted. Therefore, the (M, Zn) layer may contain indium. The In layer may contain the element M. The In layer may contain Zn. The layered structure is observed as a lattice image in a high-resolution TEM image, for example.

[0384] When a CAAC-OS film is subjected to structural analysis using an XRD apparatus, for example, a peak indicating c-axis orientation is detected at or near 2θ = 31° in out-of-plane XRD measurement using θ / 2θ scanning. Note that the position of the peak indicating c-axis orientation (the value of 2θ) may vary depending on the type or composition of the metal elements constituting the CAAC-OS.

[0385] For example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film, and the observed spots are at positions that are point-symmetric with respect to a spot of an incident electron beam that has passed through the sample (also referred to as a direct spot).

[0386] When a crystalline region is observed from the specific direction, the lattice arrangement in the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be a non-regular hexagon. The distortion may have a pentagonal, heptagonal, or other lattice arrangement. In the CAAC-OS, no clear grain boundary can be identified even near the distortion. This indicates that the distortion in the lattice arrangement suppresses the formation of grain boundaries. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of a dense arrangement of oxygen atoms in the a-b plane and the change in interatomic bond distance caused by the substitution of metal atoms.

[0387] Note that a crystal structure in which clear grain boundaries are observed is called polycrystalline. The grain boundaries act as recombination centers, and are likely to trap carriers, resulting in a decrease in the on-state current of a transistor and a decrease in field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides having a crystal structure suitable for a semiconductor layer of a transistor. Note that a structure containing Zn is preferable for forming a CAAC-OS. For example, In—Zn oxide and In—Ga—Zn oxide are suitable because they can suppress the generation of grain boundaries more effectively than In oxide.

[0388] CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by the inclusion of impurities and / or the generation of defects, the CAAC-OS can also be said to be an oxide semiconductor with few impurities and defects (oxygen vacancies, etc.). Therefore, an oxide semiconductor having a CAAC-OS has stable physical properties. Therefore, an oxide semiconductor having a CAAC-OS is heat-resistant and highly reliable. Furthermore, the CAAC-OS is stable even against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, using a CAAC-OS for an OS transistor can increase the flexibility of the manufacturing process.

[0389] [nc-OS] The nc-OS has periodic atomic arrangement in a microscopic region (e.g., a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has microcrystals. Note that the size of the microcrystals is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore the microcrystals are also called nanocrystals. Furthermore, the nc-OS does not exhibit regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Therefore, depending on the analysis method, the nc-OS may be indistinguishable from an a-like OS and an amorphous oxide semiconductor. For example, when a structural analysis of an nc-OS film is performed using an XRD apparatus, no peak indicating crystallinity is detected in out-of-plane XRD measurement using θ / 2θ scanning. When an nc-OS film is subjected to electron diffraction (also referred to as selected-area electron diffraction) using an electron beam with a probe diameter larger than that of a nanocrystal (e.g., 50 nm or more), a diffraction pattern resembling a halo pattern is observed. On the other hand, when an nc-OS film is subjected to electron diffraction (also referred to as nanobeam electron diffraction) using an electron beam with a probe diameter close to or smaller than that of a nanocrystal (e.g., 1 nm to 30 nm), an electron diffraction pattern in which multiple spots are observed within a ring-shaped region centered on a direct spot may be obtained.

[0390] [a-Like OS] The a-like OS is an oxide semiconductor having a structure between the nc-OS and an amorphous oxide semiconductor. The a-like OS has pores or low-density regions. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. Furthermore, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and CAAC-OS.

[0391] [Structure of Oxide Semiconductor] Next, the above-described CAC-OS will be described in detail. Note that the CAC-OS relates to a material structure.

[0392] [CAC-OS] CAC-OS is, for example, a material in which elements constituting a metal oxide are unevenly distributed in a size of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof. Note that hereinafter, a state in which one or more metal elements are unevenly distributed in a metal oxide and regions containing the metal elements are mixed in a size of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof, is also referred to as a mosaic or patch state.

[0393] Furthermore, the CAC-OS has a mosaic structure in which a material is separated into a first region and a second region, and the first region is distributed throughout the film (hereinafter also referred to as a cloud structure). That is, the CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0394] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In—Ga—Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In—Ga—Zn oxide, the first region is a region where [In] is larger than [In] in the composition of the CAC-OS film. The second region is a region where [Ga] is larger than [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0395] Specifically, the first region is a region whose main component is indium oxide, indium zinc oxide, or the like. The second region is a region whose main component is gallium oxide, gallium zinc oxide, or the like. In other words, the first region can be rephrased as a region whose main component is In. The second region can be rephrased as a region whose main component is Ga.

[0396] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0397] For example, in the case of CAC-OS in an In—Ga—Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) can confirm that the CAC-OS has a structure in which a region containing In as a main component (first region) and a region containing Ga as a main component (second region) are unevenly distributed and mixed.

[0398] When a CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act complementarily, thereby providing the CAC-OS with a switching function (a function of turning on / off). That is, a CAC-OS has a conductive function in a part of the material and an insulating function in a part of the material, and functions as a semiconductor as a whole. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using a CAC-OS in a transistor, a high on-current (I ｏｎ ), high field-effect mobility (μ), and good switching behavior can be achieved.

[0399] Oxide semiconductors have a variety of structures, each of which has different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS.

[0400] <Transistor Having Oxide Semiconductor> Next, a case where the oxide semiconductor is used for a transistor will be described.

[0401] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0402] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as "IGZO") as the semiconductor layer in which the channel is formed. Alternatively, an oxide containing indium (In), aluminum (Al), and zinc (Zn) (also referred to as "IAZO") may be used as the semiconductor layer. Alternatively, an oxide containing indium (In), aluminum (Al), gallium (Ga), and zinc (Zn) (also referred to as "IAGZO") may be used as the semiconductor layer.

[0403] For the transistor, an oxide semiconductor having a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 １７ cm −３Below 1 × 10, preferably １５ cm −３ More preferably, 1×10 １３ cm −３ Less than 1×10, more preferably 1×10 １１ cm −３ More preferably, 1×10 １０ cm −３ is less than 1×10 −９ cm −３ The above is the case. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, a semiconductor having a low impurity concentration and a low density of defect states is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may also be referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor.

[0404] A highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore, the density of trap states may also be low.

[0405] Charges trapped in the trap states of an oxide semiconductor take a long time to dissipate and may behave like fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0406] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in a nearby film. The impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

[0407] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0408] When an oxide semiconductor contains silicon and / or carbon, which are elements of Group 14, defect levels are formed in the oxide semiconductor. Therefore, the concentrations of silicon and carbon in the oxide semiconductor and those in the vicinity of the interface with the oxide semiconductor (concentrations obtained by SIMS) are calculated to be 2×10 １８ atoms / cm ３ Below 2 × 10, preferably １７ atoms / cm ３ The following applies.

[0409] When an oxide semiconductor contains an alkali metal or an alkaline earth metal, defect levels are formed and carriers are generated in some cases. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal is likely to have normally-on characteristics. For this reason, when the concentration of the alkali metal or the alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 １８ atoms / cm ３ Below 2 × 10, preferably １６ atoms / cm ３ Do the following:

[0410] When nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the oxide semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen in a semiconductor layer is likely to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in the oxide semiconductor obtained by SIMS is set to 5×10 １９ atoms / cm ３ Less than 5×10 １８ atoms / cm ３ Less than 1×10, more preferably 1×10 １８ atoms / cm ３ or less, more preferably 5 × 10 １７ atoms / cm ３ Do the following:

[0411] Hydrogen contained in an oxide semiconductor reacts with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. Hydrogen entering the oxygen vacancy may generate electrons as carriers. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. Therefore, it is preferable to reduce the amount of hydrogen in the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in the oxide semiconductor measured by SIMS is 1×10 ２０ atoms / cm ３ less than 1×10 １９ atoms / cm ３ less than 5×10 １８ atoms / cm ３ less than 1×10 １８ atoms / cm ３ Make it less than.

[0412] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0413] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0414] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0415] Embodiment 5 In this embodiment, for example, a specific example of a moving object according to one embodiment of the present invention will be described with reference to drawings.

[0416] 23A illustrates an automobile 601. The automobile 601 has a window 611. A moving object of one embodiment of the present invention can be applied to the automobile 601. Thus, for example, it is possible to provide an automobile that can display an image with high visibility for the driver of the automobile 601 and can reduce the occurrence of accidents.

[0417] 23B shows a bus 602. The bus 602 has a window 611. A moving body of one embodiment of the present invention can be applied to the bus 602. This makes it possible to provide a bus that can display an image that is highly visible to, for example, the driver of the bus 602 and that can reduce the occurrence of accidents.

[0418] 23C shows a train 603. The train 603 has a window 611. A moving body according to one embodiment of the present invention can be applied to the train 603. This makes it possible to provide a train that can display an image that is highly visible to the driver of the train 603 and that can reduce the occurrence of accidents.

[0419] 23D illustrates an airplane 604. The airplane 604 has a window 611. A moving object of one embodiment of the present invention can be applied to the airplane 604. In this way, it is possible to provide an airplane that can display an image with high visibility for the driver of the airplane 604 and reduce the occurrence of accidents, for example.

[0420] 23E shows a helmet 605. The helmet 605 is worn by a rider for safety when driving, for example, a motorcycle, which is a moving body. The helmet 605 has a window 611. At least a part of the moving body system of one aspect of the present invention can be applied to the helmet 605. For example, the configuration of the moving body 10 shown in FIG. 1A , excluding the driving data acquisition unit 14 and the control unit 24, can be applied to the helmet 605. In other words, the helmet 605 can be provided with, for example, an imaging unit 12, a calculation unit 16, an image generation unit 18, and a display unit 22.

[0421] The driving data acquisition unit 14 and the control unit 24 may be provided, for example, on a motorcycle driven by a person wearing a helmet 605. The driving data output by the driving data acquisition unit 14 may be supplied, for example, from the motorcycle to the helmet 605. Furthermore, the captured images acquired by the imaging unit 12 and the results of calculations by the calculation unit 16 may be supplied from the helmet 605 to the motorcycle, for example, and the control unit 24 may control the running of the motorcycle based on these.

[0422] By applying at least a part of the system for a moving body according to one embodiment of the present invention to a helmet 605, it is possible to provide a helmet that can display an image with high visibility to, for example, a rider of a motorcycle wearing the helmet 605, and that can prevent accidents from occurring. Note that the configuration is not limited to a helmet, and any other eyeglass-type wearing device may be used.

[0423] The mobile object according to one embodiment of the present invention or the system for a mobile object according to one embodiment of the present invention can be applied to objects other than the automobile, bus, train, airplane, and helmet shown in Figures 23A to 23E. For example, the mobile object according to one embodiment of the present invention can be provided in a high-speed train, a helicopter, and a tank.

[0424] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0425] Embodiment 6 In this embodiment, a display device according to one embodiment of the present invention and an electronic device according to one embodiment of the present invention using the display device will be described.

[0426] 24A is a schematic cross-sectional view showing the positional relationship between the display device 980 and the user's eyes. The display device 980 has a plurality of light-emitting elements and a plurality of light-receiving elements.

[0427] Light emitted 951 from a light-emitting element included in the display device 980 is irradiated onto the eye via the optical system 950, and the light reflected by the eye is received by a light-receiving element. The display device 980 can capture images of the periphery of the eye, the surface of the eye, or the inside of the eye (such as the fundus).

[0428] For example, the display device 980 shown in Fig. 24A has a light-emitting element and a light-receiving element, and therefore can capture an image of the fundus via the optical system 950 to obtain image data of the retinal pattern. However, when the focus is adjusted by the optical system 950, it becomes difficult to capture images of other areas. For example, when the focus is set on the fundus, the periphery of the eye is out of focus and therefore almost impossible to capture images of.

[0429] A display device according to one embodiment of the present invention includes a pixel having a light-emitting element and a light-receiving element. Since the pixel has a light-receiving function, the display device according to one embodiment of the present invention can detect contact or proximity of an object while displaying an image. Furthermore, since the display device according to one embodiment of the present invention includes a subpixel that emits infrared light, the display device can also display an image while emitting infrared light as a light source using the subpixel.

[0430] Furthermore, in a display device according to one embodiment of the present invention, light-emitting elements are arranged in a matrix in a display portion, and an image can be displayed on the display portion. Furthermore, light-receiving elements are arranged in a matrix in the display portion, and the display portion has one or both of an imaging function and a sensing function in addition to an image display function. The display portion can be used as an image sensor. That is, an image can be captured by detecting light in the display portion, or an object (movement of an eye, eyelid, or eyeball) can be detected by periodically monitoring the image. Furthermore, in the display device according to one embodiment of the present invention, light-emitting elements can be used as a light source for a sensor. Therefore, a light-receiving portion and a light source are not required separately from the display device, and the number of components in an electronic device can be reduced.

[0431] First, a method for detecting the blinking and eyelid movement of a user will be described below with reference to FIGS. 24A and 24B.

[0432] <Blinking and Eyelid Movement> Near-infrared light is emitted from the display device 980. This near-infrared light is irradiated onto the user's eyes or the vicinity of the user's eyes through the optical system 950. The reflected light passes through the optical system 950 again and is incident on the display device 980. This makes it possible to detect the state of the object.

[0433] 24B is a schematic diagram illustrating the user's eyes and the vicinity of the user's eyes. Fig. 24B shows the user's eyebrows 960, the user's eyelids (upper eyelid 966 and lower eyelid 967), the user's eyelashes 961, the user's pupils 962, the user's cornea 963, and the user's sclera 965. The display device 980 has a function of capturing an image of one or more selected from the user's eyebrows 960, the user's eyelids (upper eyelid 966 and lower eyelid 967), the user's eyelashes 961, the user's pupils 962, the user's cornea 963, and the user's sclera 965 shown in Fig. 24B.

[0434] For example, an electronic device of one embodiment of the present invention can detect the state of the user's eyes or the vicinity of the user's eyes shown in FIG. 24B using the display device 980. For example, when the user's eyelids (upper eyelid 966 and lower eyelid 967) are closed, near-infrared light is irradiated onto the surfaces of the eyelids, i.e., onto the skin. When the eyelids are open, near-infrared light is irradiated onto the surface of the eyeball. Since the reflectance of the skin and the surface of the eyeball differs, the intensity of the reflected near-infrared light differs. By continuously monitoring this state, the display device 980 can detect one or both of the number of blinks and the time required for one blink.

[0435] When viewing a display for a long period of time, the number of times a person blinks may decrease. Also, when a user becomes tired, the interval between blinks may become longer and the duration of each blink may become longer.

[0436] In the electronic device of one embodiment of the present invention, the level of fatigue of a user can be estimated from one or both of the number of blinks of the user and the time taken for one blink.

[0437] <Movement of the pupil> When a circular spot of infrared light is applied to the boundary region between the cornea (e.g., cornea 963 shown in FIG. 24B ) and the sclera (e.g., sclera 965 shown in FIG. 24B ), the ratio of the area covering the cornea to the area covering the sclera changes as the eyeball moves within the irradiation range of the infrared light spot. Because the reflectance from the area covering the sclera is overwhelmingly greater than that from the area covering the cornea, the amount of reflected light changes as the eyeball moves. By measuring this change, it becomes possible to detect the direction in which the user is looking.

[0438] <Scleral Reflection Method> Next, the scleral reflection method will be described. Near-infrared light is emitted from the display device 980. This near-infrared light is irradiated onto the user's eyes through the optical system 950. The reflected light passes through the optical system 950 again and enters the display device 980. This makes it possible to detect the state of an object. When viewing a displayed image, the gaze shifts when viewing a fast-moving object. When the gaze shifts, the eyeball moves. When the eyeball moves, the ratio of the area irradiated with infrared light that covers the cornea to the area that covers the sclera changes, so it is possible to monitor the reflected light component and detect the movement of the eyeball. That is, an electronic device according to one embodiment of the present invention has an eye tracking function.

[0439] Eye tracking can detect the user's line of sight, making it possible to estimate the area the user is gazing at. Variable rate shading can then be used to reduce the resolution of areas other than the area the user is gazing at, thereby reducing the amount of calculations and power consumption of electronic devices.

[0440] The electronic device of one embodiment of the present invention includes both a light-emitting element and a sensor device in the display device 980, which enables the number of components to be reduced. In other words, the electronic device of one embodiment of the present invention includes both a light-emitting element and a sensor device, which eliminates the need for a fingerprint authentication device, a touch panel device, or the like. Therefore, one embodiment of the present invention can provide an electronic device with reduced manufacturing costs.

[0441] Next, fundus diagnosis of the user's eye will be described with reference to FIGS. 24A and 24C.

[0442] <Fundus Diagnosis> As shown in FIG. 24A , the user's eye is composed of a lens 942, a retina 941, an optic nerve 943, a vitreous body 947, a choroid 948, a cornea, and other components. The pupil is located between the cornea and the lens, but for simplicity, the cornea and pupil are not shown. The ciliary body is a tissue that continues from the iris, and the choroid 948 is a tissue that continues from the ciliary body. The iris and pupil function like a camera aperture to adjust the light irradiated onto the retina 941. The pattern of the retina 941, known as the retinal pattern, is said to remain essentially unchanged from birth to death, and the retinal pattern can be used for personal authentication, for example. The retinal pattern obtained by the display device 980 can be used to perform eye diagnoses even in remote locations.

[0443] By adjusting the optical system 950, the display device 980 can detect one or more of the blinking, the movement of the pupil, and the movement of the eyelid of the user without focusing on the fundus. That is, the electronic device of one embodiment of the present invention has a function of detecting eye strain.

[0444] Next, Figure 24C shows an example of the obtained retinal pattern for a right eye. In the retina 941, an optic disc 944, a vein 945, an artery 946, a macula, a fovea, and the like can be observed. The optic disc 944 refers to the boundary between the optic nerve 943 and the retina 941, and the vein 945 or the artery 946 is arranged so that it spreads out from the optic disc 944. The fundus refers to the part behind the eyeball and is a collective term for the retina 941, vitreous body 947, choroid 948, and optic disc 944. In the case of the left eye, the optic disc 944 is located on the left side of the retinal pattern, resulting in a retinal pattern that is a left-right inversion of the retinal pattern for the right eye in Figure 24C.

[0445] In order to acquire the retinal pattern of the fundus using the light receiving element of the display device 980, the pupil needs to be dilated. In order to dilate the pupil and capture an image of the fundus, the display is changed in the following procedure: The display screen of the display device 980 is gradually darkened to allow the user's eyes to dark adapt. The display screen is brightened for a short period of time, less than 16.7 ms, and then the image is captured. After that, the display screen is gradually returned to its original brightness.

[0446] Furthermore, the electronic device of one embodiment of the present invention can detect the degree of eye fatigue of a user by using the display device 980. When capturing an image with the display screen brightened for a certain period, if the user blinks, the image cannot be captured. Therefore, by detecting the number of blinks, the timing, or the length of time the eyes are closed, the degree of eye fatigue can be estimated from the number of blinks, the interval between blinks, the length of time the eyes are closed, or the like by using a system using AI (Artificial Intelligence).

[0447] Furthermore, while the display screen of the display device 980 is darkened, multiple images may be taken to detect the user's eye fatigue level. By taking multiple images, the pulsation of retinal blood vessels can be detected, and the user's state of rest or tension can be determined using an AI-based system. Furthermore, various data obtained by the display device 980 can be used to diagnose high blood pressure or diabetes using an AI-based system. When using an AI-based system, a control circuit is installed in the electronic device or the display device 980. The control circuit uses a CPU (Central Processor Unit) or a GPU (Graphics Processing Unit). The control circuit can also use an APU (Accelerated Processing Unit), which is a chip that integrates a CPU and a GPU. An IC (also called an inference chip) incorporating an AI system may also be used. An IC incorporating an AI system is sometimes called a circuit (microprocessor) that performs neural network calculations.

[0448] Furthermore, while the display screen of the display device 980 is darkened, a pattern that is easy to notice may be displayed on the display screen of the display device 980 to control the orientation of the eyeballs.

[0449] The distance between the display device 980 and the surface of the eye (for example, the cornea) is preferably 2 cm or less. To achieve this positional relationship, an optical system 950 with a short focal length is placed between the display device 980 and the eye.

[0450] When the screen is magnified 10 times by the optical system 950, for example, if the display screen of the display device 980 has a diagonal size of about 1 inch and a resolution (definition) of about 2450 ppi, the pitch of the sensor pixels is about 10.4 μm. Since the diameter of each of the retinal veins 945 and arteries 946 is smaller than about 100 μm, they can be imaged using the display device 980.

[0451] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0452] 10: moving body, 12: imaging unit, 14: driving data acquisition unit, 16: calculation unit, 18: image generation unit, 22: display unit, 24: control unit, 31: window unit, 33: light, 35: display device, 37: imaging device, 39: semiconductor device, 42: display image, 44: arrow, 46: arrow, 48a: building, 48b: building, 49: person, 123: CPU, 124: GPU, 125: memory circuit unit, 129: input / output terminal unit, 140: layer, 150: layer, 151: pixel circuit, 160: layer, 161: light-emitting element, 161B: light-emitting element, 161G: light-emitting element, 161R: light-emitting element, 161W: light-emitting element, 17 1: conductive layer, 172: EL layer, 172a: EL layer, 172b: EL layer, 172B: EL layer, 172G: EL layer, 172R: EL layer, 172W: EL layer, 173: conductive layer, 175B: light, 175G: light, 175R: light, 230: pixel, 231: drive circuit unit, 232: drive circuit unit, 233: pixel, 235: display area, 236: wiring, 237: wiring, 240: pixel, 241: conductive layer, 243: insulating layer, 245: conductive layer, 246: capacitance, 251: conductive layer, 252: conductive layer, 254: insulating layer, 255: insulating layer, 256: plug, 261: insulating layer, 262: insulating layer, 263: insulating layer, 264: insulating layer, 264B: colored layer, 264G: colored layer, 264R: colored layer, 265: insulating layer, 266: plug, 271: protective layer, 272: insulating layer, 273: protective layer, 274: plug, 274a: conductive layer, 274b: conductive layer, 275: region, 276: insulating layer, 277: microlens array, 301: substrate, 301A: substrate, 301B: substrate, 310: transistor, 310A: transistor, 310B: transistor, 311: conductive layer, 312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 320: transistor transistor, 321: semiconductor layer, 323: insulating layer, 324: conductive layer, 325: conductive layer, 326: insulating layer, 327: conductive layer, 328: insulating layer, 329: insulating layer, 331: substrate, 332: insulating layer, 341: conductive layer, 342: conductive layer, 343: plug, 363: insulating layer, 415: protective layer, 419: resin layer, 420: substrate, 500: transistor, 505: conductive layer, 505a: conductive layer, 505b: conductive layer, 505c: conductive layer, 514: insulating layer, 516: insulating layer, 522: insulating layer, 524: insulating layer, 531: metal oxide, 531a: metal oxide, 531b: metal oxide,531c: metal oxide, 541: insulating layer, 541a: insulating layer, 541b: insulating layer, 542: conductive layer, 542a: conductive layer, 542b: conductive layer, 545: conductive layer, 545a: conductive layer, 545b: conductive layer, 550: insulating layer, 554: insulating layer, 560: conductive layer, 560a: conductive layer, 560b: conductive layer, 574: insulating layer, 580: insulating layer, 581: insulating layer, 601: automobile, 602: bus, 603: train, 604: airplane, 605: helmet, 611: window, 941: retina , 942: lens, 943: optic nerve, 944: optic disc, 945: vein, 946: artery, 947: vitreous body, 948: choroid, 950: optical system, 951: light emission, 960: eyebrow, 961: hair, 962: pupil, 963: cornea, 965: sclera, 966: upper eyelid, 967: lower eyelid, 980: display device, 4411: light-emitting layer, 4412: light-emitting layer, 4413: light-emitting layer, 4420: layer, 4420-1: layer, 4420-2: layer, 4430: layer, 4430-1: layer, 4430-2: layer,

Claims

1. A moving body having a display unit, an imaging unit, a driving data acquisition unit, and a calculation unit, The display unit has a function of displaying a display image, the imaging unit has a function of acquiring a first captured image including the display image and an outside scene superimposed on the display image, and a second captured image including a driver of the moving object; The driving data acquisition unit has a function of acquiring driving data, The calculation unit has a function of estimating a state of the driver based on the second captured image, The calculation unit has a function of estimating a cause of the driver's state based on the first captured image and the driving data, The calculation unit is a moving body having a function of correcting the display image based on the cause.

2. In claim 1, The driving data includes at least a change in a traveling speed of the moving body over time.

3. In claim 2, A moving body, wherein the state of the driver is drowsiness of the driver.

4. In claim 1, The second captured image is of a moving object including the face of the driver.

5. In claim 1, the calculation unit has a function of detecting an object included in the first captured image, The calculation unit is a moving body having a function of correcting the display image based on the object and the driving data.

6. In claim 1, the calculation unit has a function of detecting an object included in the first captured image, The calculation unit has a function of correcting the display image based on the object and the driving data, The calculation unit is a moving body having a function of changing the transmittance of the display image when a specified number or more of people are detected as the object.

7. In claim 5, The driving data includes at least one of an accelerator operation frequency and a brake operation frequency, The calculation unit has a function of changing the transmittance of the display image when the frequency of operation of the accelerator or the frequency of operation of the brake is equal to or greater than a specified value.

8. In claim 6, The calculation unit is a moving body having a function of changing the transmittance of the display image when a specified number or more of people are detected as the object.

9. In claim 7, The moving body has a control unit, The control unit is a moving body having a function of controlling the traveling of the moving body based on the first captured image.