Optical device

Abstract

An optical apparatus according to the present invention is provided with a display device (10) and an optical system (12). The display device (10) is provided with a display region (60) and a sensor region (52). The optical system (12) is provided with a first mirror (21) and a second mirror (22). The first mirror (21) is provided with a first surface and a second surface. The display region (60) is provided with a function of emitting first light (31). The first mirror (21) is provided on an optical path of the first light (31), and is provided with a function of enabling the first light (31) entering the first surface to pass through the second surface and a function of reflecting second light (33) entering the second surface. The second mirror (22) is provided on an optical path of the second light (33) and is provided with a function of reflecting the second light (33). The sensor region (52) is provided with a function of detecting the second light (33) via the first mirror (21) and the second mirror (22).

Description

optical device

[0001] One aspect of the present invention relates to an optical device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, a driving 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 semiconductor devices, display devices, light-emitting devices, power storage devices, optical devices, imaging devices, memory devices, signal processing devices, electronic devices, lighting devices, input devices, input / output devices, and driving methods thereof or manufacturing methods thereof.

[0003] In recent years, electronic devices for virtual reality (sometimes referred to as VR) or augmented reality (sometimes referred to as AR) have been attracting attention. Furthermore, electronic devices for VR or AR equipped with a gaze detection (eye tracking) function have been developed. Electronic devices for VR or AR equipped with a gaze detection function can be applied to, for example, consumer behavior analysis, image processing, avatar creation, or gaze-based operation.

[0004] For example, Patent Document 1 discloses an electronic device for VR or AR that has a line-of-sight detection function.

[0005] International Publication No. 2019 / 158709

[0006] Electronic devices for VR or AR equipped with a gaze detection function need to be provided with an imaging system (e.g., an image sensor or a control IC) in addition to a display system (e.g., a display or a driver). Also, the optical system needs to be appropriately adjusted to match the positional relationship between the eyes of the user of the electronic device and the display system and imaging system.

[0007] An object of one embodiment of the present invention is to provide a miniaturized optical device or electronic device.An object of one embodiment of the present invention is to provide a miniaturized optical device or electronic device with a line-of-sight detection function.An object of one embodiment of the present invention is to provide a novel optical device or electronic device.An object of one embodiment of the present invention is to provide a novel optical device or electronic device with a line-of-sight detection function.

[0008] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description of this specification, drawings, claims, etc.

[0009] (1) One aspect of the present invention is an optical device including a display device and an optical system, wherein the display device includes a display region and a sensor region, the optical system includes a first mirror and a second mirror, the first mirror includes a first surface and a second surface, the display region has a function of emitting first light, the first mirror is provided on an optical path of the first light and has a function of transmitting the first light incident on the first surface to the second surface and a function of reflecting second light incident on the second surface, the second mirror is provided on the optical path of the second light and has a function of reflecting the second light, and the sensor region has a function of detecting the second light via the first mirror and the second mirror.

[0010] (2) In addition, in the above (1), the optical system may be an optical device including a light source, the light source having a function of emitting third light, and the second light being reflected light from an object irradiated with the third light.

[0011] (3) In addition, in the above (1), the display device may be an optical device that includes a light source, the light source having a function of emitting third light, and the second light being reflected light from an object irradiated with the third light.

[0012] (4) In the above (2) or (3), the third light is preferably infrared light.

[0013] (5) In any one of (1) to (4) above, the sensor area may be provided so as to overlap the display area.

[0014] (6) In any one of (1) to (5) above, the optical system may include a first lens, and the first lens may be provided on an optical path of the first light and have a function of controlling the optical path of the first light.

[0015] (7) In any one of (1) to (6) above, the display device may further include a second lens, which is disposed between the second mirror and the sensor region and has a function of controlling the optical path of the second light.

[0016] (8) In addition, in any one of (1) to (6) above, the display device may include a pinhole, which is provided between the second mirror and the sensor area and has a function of controlling the optical path of the second light.

[0017] (9) In addition, in any one of (1) to (8) above, the display device may include a gaze detection unit, and the gaze detection unit may have a function of detecting the gaze of the user using imaging data acquired in the sensor area.

[0018] One embodiment of the present invention can provide a miniaturized optical device or electronic device. Alternatively, one embodiment of the present invention can provide a miniaturized optical device or electronic device having a line-of-sight detection function. Alternatively, one embodiment of the present invention can provide a novel optical device or electronic device. Alternatively, one embodiment of the present invention can provide a novel optical device or electronic device having a line-of-sight detection function.

[0019] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these can be extracted from the description in this specification, drawings, claims, etc.

[0020] FIGS. 1A and 1B are diagrams illustrating an example of the configuration of an electronic device. FIG. 2 is a diagram illustrating an example of the configuration of an optical device. FIG. 3 is a diagram illustrating an example of the configuration of an optical device. FIGS. 4A and 4B are diagrams illustrating an example of the configuration of a display device. FIG. 5 is a diagram illustrating an example of the configuration of an optical device. FIG. 6 is a diagram illustrating an example of the configuration of a display device. FIG. 7 is a diagram illustrating an example of the configuration of an optical device. FIGS. 8A and 8B are diagrams illustrating an example of the configuration of a display device. FIG. 9 is a diagram illustrating an example of the configuration of a display device. FIGS. 10A and 10B are diagrams illustrating an example of the configuration of a display device. FIG. 11 is a diagram illustrating an example of the configuration of a display device. FIGS. 12A and 12B are diagrams illustrating an example of the operation of an electronic device. FIG. 13 is a flowchart illustrating an example of the operation of an electronic device. FIGS. 14A and 14B are diagrams illustrating an example of the configuration of a display device. FIGS. 15A and 15B are diagrams illustrating an example of the configuration of a display device. FIGS. 16A and 16B are diagrams illustrating an example of the configuration of a display device. FIGS. 17A and 17B are diagrams illustrating an example of the configuration of a display device. FIGS. 18A and 18B are diagrams illustrating an example of the configuration of a display device. 19A and 19B are diagrams showing a configuration example of a display device. FIGS. 20A to 20E are diagrams showing a configuration example of a display device. FIGS. 21A and 21B are diagrams showing a configuration example of a display device. FIGS. 22A and 22B are diagrams showing a configuration example of a display device. FIGS. 23A and 23B are diagrams showing a configuration example of a display device. FIGS. 24A to 24D are diagrams showing a configuration example of a light-emitting element. FIG. 25 is a diagram showing a configuration example of a display device. FIG. 26 is a diagram showing a configuration example of a display device. FIG. 27A is a top view showing a configuration example of a transistor. FIGS. 27B and 27C are cross-sectional views showing configuration examples of a transistor.

[0021] In this specification, a semiconductor device is a device that utilizes semiconductor characteristics, and refers to, for example, a circuit including a semiconductor element (e.g., a transistor, a diode, or a photodiode), or a device having such a circuit. It also refers to any device that can function by utilizing semiconductor characteristics. For example, an integrated circuit, a chip including an integrated circuit, or an electronic component that houses a chip in a package are examples of semiconductor devices. Furthermore, for example, a memory device, a display device, a light-emitting device, a lighting device, or an electronic device may be a semiconductor device and may also include a semiconductor device.

[0022] Furthermore, when it is stated in this specification that X and Y are connected, it is understood that the following cases are disclosed in this specification: when X and Y are electrically connected, when X and Y are functionally connected, and when X and Y are directly connected. Therefore, it is not limited to a specific connection relationship, for example, a connection relationship shown in a figure or text, and it is understood that connections other than those shown in a figure or text are also disclosed in a figure or text. X and Y are each an object (e.g., a device, an element, a circuit, wiring, an electrode, a terminal, a conductive film, or a layer, etc.).

[0023] As an example of the case where X and Y are electrically connected, one or more elements (e.g., a switch, a transistor, a capacitance element, an inductor, a resistance element, a diode, a display device, a light-emitting device, or a load) that enable the electrical connection between X and Y can be connected between X and Y.

[0024] As an example of a case where X and Y are functionally connected, one or more circuits that enable the functional connection between X and Y (for example, a logic circuit (for example, an inverter, a NAND circuit, or a NOR circuit), a signal conversion circuit (for example, a digital-to-analog conversion circuit, an analog-to-digital conversion circuit, or a gamma correction circuit), a potential level conversion circuit (for example, a power supply circuit (for example, a step-up circuit or a step-down circuit), or a level shifter circuit that changes the potential level of a signal), a voltage source, a current source, a switching circuit, an amplifier circuit (for example, a circuit that can increase the signal amplitude or current amount, an operational amplifier, a differential amplifier circuit, a source follower circuit, or a buffer circuit), a signal generation circuit, a memory circuit, or a control circuit) can be connected between X and Y. As an example, even if another circuit is sandwiched between X and Y, X and Y are considered to be functionally connected if a signal output from X is transmitted to Y.

[0025] It should be noted that when it is explicitly stated that X and Y are electrically connected, this includes the case where X and Y are electrically connected (i.e., the case where X and Y are connected with another element or another circuit sandwiched between them) and the case where X and Y are directly connected (i.e., the case where X and Y are connected without another element or another circuit sandwiched between them).

[0026] Furthermore, for example, it can be expressed as follows: "X, Y, and the source (or first terminal, etc.) and drain (or second terminal, etc.) of the transistor are electrically connected to each other, and are electrically connected in the order of X, the source (or first terminal, etc.) of the transistor, the drain (or second terminal, etc.) of the transistor, and Y." Or, it can be expressed as follows: "The source (or first terminal, etc.) of the transistor is electrically connected to X, and the drain (or second terminal, etc.) of the transistor is electrically connected to Y, and X, the source (or first terminal, etc.) of the transistor, the drain (or second terminal, etc.) of the transistor, and Y are electrically connected in this order." Or, it can be expressed as follows: "X is electrically connected to Y via the source (or first terminal, etc.) and drain (or second terminal, etc.) of the transistor, and X, the source (or first terminal, etc.) of the transistor, the drain (or second terminal, etc.) of the transistor, and Y are provided in this connection order." By using expressions similar to these examples to define the order of connections in a circuit configuration, the source (or first terminal, etc.) and the drain (or second terminal, etc.) of a transistor can be distinguished and the technical scope can be determined. Note that these expressions are merely examples and are not limiting. Here, X and Y are assumed to be objects (e.g., a device, an element, a circuit, a wiring, an electrode, a terminal, a conductive film, or a layer, etc.).

[0027] Note that even when independent components are shown electrically connected in a circuit diagram, one component may have the functions of multiple components. For example, if part of a wiring also functions as an electrode, one conductive film has the functions of both the wiring and the electrode. Therefore, the term "electrically connected" in this specification also includes such cases where one conductive film has the functions of multiple components.

[0028] Furthermore, in this specification, the term "resistive element" may refer to, for example, a circuit element or wiring having a resistance value higher than 0 Ω. Therefore, in this specification, the term "resistive element" includes, for example, wiring having a resistance value, a transistor in which a current flows between the source and drain, a diode, or a coil. Therefore, the term "resistive element" may be replaced with, for example, terms such as "resistance," "load," or "region having a resistance value." Conversely, the terms "resistance," "load," or "region having a resistance value" may be replaced with, for example, terms such as "resistive element." The resistance value may be, for example, preferably 1 mΩ or more and 10 Ω or less, more preferably 5 mΩ or more and 5 Ω or less, and even more preferably 10 mΩ or more and 1 Ω or less. Furthermore, for example, the resistance value may be, for example, 1 Ω or more and 1×10 ９ It may be set to Ω or less.

[0029] When a wiring is used as a resistor, the resistance value of the resistor may be determined by the length of the wiring. Alternatively, the resistor may use a conductor having a different resistivity from the conductor used as the wiring. Alternatively, when a semiconductor is used as a resistor, the resistance value of the resistor may be determined by doping impurities into the semiconductor.

[0030] Furthermore, in this specification, the term "capacitive element" can refer to, for example, a circuit element having a capacitance value higher than 0 F, a region of wiring having a capacitance value higher than 0 F, a parasitic capacitance, or a gate capacitance of a transistor. Therefore, in this specification, the term "capacitive element" is not limited to a circuit element including a pair of electrodes and a dielectric between the electrodes. The term "capacitive element" also includes, for example, a parasitic capacitance occurring between wirings, or a gate capacitance occurring between one of the source or drain of a transistor and the gate. Furthermore, terms such as "capacitive element," "parasitic capacitance," and "gate capacitance" can be replaced with terms such as "capacitance." Conversely, the term "capacitance" can be replaced with terms such as "capacitive element," "parasitic capacitance," and "gate capacitance." Furthermore, the term "pair of electrodes" in "capacitance" can be replaced with, for example, a "pair of conductors," a "pair of conductive regions," or a "pair of regions." The capacitance value can be, for example, 0.05 fF or more and 10 pF or less. Alternatively, it may be set to, for example, 1 pF or more and 10 μF or less.

[0031] Furthermore, in this specification, a transistor has three terminals called a gate, a source, and a drain. The gate is a control terminal that controls the amount of current flowing between the source and the drain. The two terminals that function as a source or a drain are the input / output terminals of the transistor. One of the two input / output terminals serves as a source and the other as a drain depending on the transistor's conductivity type (n-channel or p-channel) and the level of the potential applied to the three terminals. Therefore, in this specification, the terms "source" and "drain" are interchangeable. Furthermore, when describing the connection relationship of a transistor, the terms "one of the source or drain" (or first electrode or first terminal) and "the other of the source or drain" (or second electrode or second terminal) are used. Note that, depending on the structure, a transistor may have a backgate in addition to the three terminals described above. In this case, in this specification, one of the gate or backgate of the transistor may be referred to as the first gate, and the other of the gate or backgate of the transistor may be referred to as the second gate. Furthermore, for the same transistor, the terms "gate" and "backgate" may be interchangeable. Furthermore, when a transistor has three or more gates, in this specification and the like, the respective gates may be referred to as, for example, a first gate, a second gate, a third gate, or the like.

[0032] Furthermore, in this specification and the like, a "node" can be rephrased as, for example, a "terminal," "wiring," "electrode," "conductive layer," "conductor," or "impurity region," depending on, for example, the circuit configuration or the device structure. Furthermore, for example, a "terminal" or "wiring" can be rephrased as a "node."

[0033] Furthermore, in this specification and the like, the terms "voltage" and "potential" can be interchanged as appropriate. "Voltage" refers to a potential difference from a reference potential. For example, if the reference potential is the ground potential (earth potential), then "voltage" can be interchanged with "potential." Note that ground potential does not necessarily mean 0 V. Furthermore, potential is relative. In other words, as the reference potential changes, for example, the potential applied to a wiring, the potential applied to a circuit, or the potential output from a circuit also changes.

[0034] Furthermore, in this specification and the like, the terms "high-level potential (also referred to as "high-level potential," "H potential," or "H")" and "low-level potential (also referred to as "low-level potential," "L potential," or "L")" do not refer to any particular potential. For example, when two wirings are both described as "functioning as wirings that supply a high-level potential," the high-level potentials provided by both wirings do not have to be equal to each other. Similarly, when two wirings are both described as "functioning as wirings that supply a low-level potential," the low-level potentials provided by both wirings do not have to be equal to each other.

[0035] Furthermore, in this specification, "electric current" refers to the phenomenon of charge transfer (electrical conduction). For example, the statement "electrical conduction of positively charged bodies is occurring" can be rephrased as "electrical conduction of negatively charged bodies is occurring in the opposite direction." Therefore, in this specification, unless otherwise specified, "electric current" refers to the phenomenon of charge transfer (electrical conduction) associated with the movement of carriers. Examples of carriers include electrons, holes, anions, cations, and complex ions. Note that carriers vary depending on the system through which the current flows (e.g., semiconductor, metal, electrolyte, vacuum, etc.). Furthermore, the "direction of current" in, for example, wiring, is the direction in which positive carriers move and is expressed as a positive current amount. In other words, the direction in which negative carriers move is opposite to the direction of current and is expressed as a negative current amount. Therefore, in this specification and the like, unless otherwise specified regarding the positive or negative sign (or direction of the current), a statement such as "current flows from element A to element B" can be rephrased as "current flows from element B to element A," etc. Furthermore, a statement such as "current is input to element A" can be rephrased as "current is output from element A," etc.

[0036] Furthermore, in this specification, the ordinal numbers "first," "second," and "third" are used to avoid confusion between components. Therefore, they do not limit the number of components. Furthermore, they do not limit the order of the components. For example, a component referred to as "first" in one embodiment of this specification may be referred to as "second" in another embodiment or in the claims. Furthermore, for example, a component referred to as "first" in one embodiment of this specification may be omitted in another embodiment or in the claims.

[0037] Furthermore, in this specification, terms indicating arrangement, such as "above," "below," "upward," or "belowward," may be used for convenience in describing the positional relationship between components with reference to drawings. Furthermore, the positional relationship between components changes as appropriate depending on the orientation in which each component is depicted. Therefore, terms indicating arrangement described in this specification are not limited to these terms and can be rephrased appropriately depending on the situation. For example, the expression "insulator located on the upper surface of a conductor" can be rephrased as "insulator located on the lower surface of a conductor" by rotating the orientation of the drawing by 180 degrees. Furthermore, the expression "insulator located on the upper surface of a conductor" can be rephrased as "insulator located on the left (or right) surface of a conductor" by rotating the orientation of the drawing by 90 degrees.

[0038] Furthermore, the terms "above" and "below" do not limit the positional relationship of components to being directly above or below and in direct contact with each other. For example, the expression "electrode B on insulating layer A" does not necessarily mean that electrode B is formed on insulating layer A in direct contact with it, and does not exclude the inclusion of other components between insulating layer A and electrode B.

[0039] Furthermore, in this specification and the like, the term "overlap" does not limit the state of, for example, the stacking order of components. For example, the expression "electrode B overlapping insulating layer A" is not limited to the state in which electrode B is formed on insulating layer A. The expression "electrode B overlapping insulating layer A" does not exclude, for example, the state in which electrode B is formed under insulating layer A, or the state in which electrode B is formed on the right (or left) side of insulating layer A.

[0040] Furthermore, in this specification and the like, the terms "adjacent" or "close to" do not limit components to being in direct contact with each other. For example, the expression "electrode B adjacent to insulating layer A" does not necessarily mean that insulating layer A and electrode B are formed in direct contact with each other, and does not exclude the inclusion of other components between insulating layer A and electrode B.

[0041] Furthermore, in this specification and the like, terms such as "film" or "layer" may be interchangeable depending on the situation. For example, the term "conductive layer" may be interchangeable with the term "conductive film." For example, the term "insulating film" may be interchangeable with the term "insulating layer." Furthermore, terms such as "film" or "layer" may be interchangeable with other terms depending on the situation without using those terms. For example, the term "conductive layer" or "conductive film" may be interchangeable with the term "conductor." Furthermore, the term "conductor" may be interchangeable with the term "conductive layer" or "conductive film." For example, the term "insulating layer" or "insulating film" may be interchangeable with the term "insulator." Furthermore, the term "insulator" may be interchangeable with the term "insulating layer" or "insulating film."

[0042] Furthermore, in this specification and the like, terms such as "electrode," "wiring," or "terminal" do not functionally limit these components. For example, an "electrode" may be used as part of a "wiring," and vice versa. Furthermore, the terms "electrode" or "wiring" include, for example, cases where multiple "electrodes" or "wirings" are integrally formed. Furthermore, for example, a "terminal" may be used as part of a "wiring" or "electrode," and vice versa. Furthermore, the term "terminal" includes, for example, cases where multiple "electrodes," "wirings," or "terminals" are integrally formed. Therefore, for example, an "electrode" can be part of a "wiring" or "terminal." Furthermore, for example, a "terminal" can be part of a "wiring" or "electrode." Furthermore, for example, terms such as "electrode," "wiring," or "terminal" may be replaced with, for example, a term such as "region."

[0043] Furthermore, in this specification and the like, terms such as "wiring," "signal line," or "power line" may be interchangeable depending on the situation. For example, the term "wiring" may be changed to the term "signal line." For example, the term "wiring" may be changed to the term "power line." The reverse is also true, for example, terms such as "signal line" or "power line" may be changed to the term "wiring." The term "power line" may be changed to the term "signal line." The reverse is also true, for example, terms such as "signal line" may be changed to the term "power line." The term "potential" applied to wiring may be changed to the term "signal" depending on the situation. The reverse is also true, for example, terms such as "signal" may be changed to the term "potential."

[0044] In addition, in this specification, a "switch" has multiple terminals and has the function of switching (selecting) conduction or non-conduction between the terminals. For example, if a switch has two terminals and both terminals are conductive, the switch is said to be in a "conductive state" or "on state." Also, if both terminals are non-conductive, the switch is said to be in a "non-conductive state" or "off state." Note that switching the switch to either the conductive state or the non-conductive state, or maintaining either the conductive state or the non-conductive state, may be referred to as "controlling the conduction state."

[0045] In other words, a switch is a device that has the function of controlling whether or not a current flows. Alternatively, a switch is a device that has the function of selecting and switching the path through which a current flows. For example, an electrical switch or a mechanical switch can be used as the switch. In other words, the switch is not limited to a specific one as long as it can control a current.

[0046] There are types of switches that are normally non-conductive but can be made conductive by controlling the conductive state, and these switches are sometimes called "contact A." There are also types of switches that are normally conductive but can be made non-conductive by controlling the conductive state, and these switches are sometimes called "contact B."

[0047] Examples of switches include transistors (e.g., bipolar transistors or MOS transistors), diodes (e.g., PN diodes, PIN diodes, Schottky diodes, MIM (Metal Insulator Metal) diodes, MIS (Metal Insulator Semiconductor) diodes, or diode-connected transistors), or logic circuits combining these. When a transistor is used as a switch, the "conductive state" or "on state" of the transistor refers to a state in which the source electrode and drain electrode of the transistor can be considered to be electrically short-circuited. Furthermore, the "non-conductive state" or "off state" of the transistor refers to a state in which the source electrode and drain electrode of the transistor can be considered to be electrically disconnected. When a transistor is operated simply as a switch, the polarity (conductivity type) of the transistor is not particularly limited.

[0048] An example of a mechanical switch is a switch that uses MEMS (microelectromechanical systems) technology. This switch has an electrode that can be mechanically moved, and the movement of the electrode selects a conductive state or a non-conductive state.

[0049] In this specification, "parallel" refers to a state in which two straight lines are arranged at an angle of -10° or more and 10° or less. Therefore, it also includes cases where the angle is -5° or more and 5° or less. Furthermore, "substantially parallel" or "roughly parallel" refers to a state in which two straight lines are arranged at an angle of -30° or more and 30° or less. Furthermore, "perpendicular" refers to a state in which two straight lines are arranged at an angle of 80° or more and 100° or less. Therefore, it also includes cases where the angle is 85° or more and 95° or less. Furthermore, "substantially perpendicular" or "approximately perpendicular" refers to a state in which two straight lines are arranged at an angle of 60° or more and 120° or less.

[0050] In this specification, when referring to counting values ​​and measurement values, or to objects, methods, and events that can be converted into counting values ​​or measurement values, terms such as "identical," "same," "equal," or "uniform" (including synonyms thereof) are used, these terms are considered to include an error of plus or minus 20%, unless otherwise specified.

[0051] In this specification and the like, the term "impurities" in a semiconductor refers to, for example, elements other than the main component constituting the semiconductor layer. For example, an element with a concentration of less than 0.1 atomic % is an impurity. The presence of impurities in a semiconductor may result in, for example, an increase in the defect level density of the semiconductor, a decrease in carrier mobility, or a decrease in crystallinity. When the semiconductor is an oxide semiconductor, examples of impurities that change the characteristics of the semiconductor include, for example, Group 1 elements, Group 2 elements, Group 13 elements, Group 14 elements, Group 15 elements, or transition metals other than the main component of the oxide semiconductor. In particular, examples of impurities include hydrogen (also contained in water), lithium, sodium, silicon, boron, phosphorus, carbon, and nitrogen. Furthermore, when the semiconductor is a silicon layer, examples of impurities that change the characteristics of the semiconductor include, for example, oxygen, Group 1 elements excluding hydrogen, Group 2 elements, Group 13 elements, and Group 15 elements.

[0052] In this specification and the like, a metal oxide refers to an oxide of a metal in a broad sense. Metal oxides are classified into, for example, oxide insulators, oxide conductors (including transparent oxide conductors), and oxide semiconductors (also referred to as oxide semiconductors or simply as OSs). For example, when a metal oxide is used for a semiconductor layer of a transistor, the metal oxide may be referred to as an oxide semiconductor. That is, when a metal oxide is used as a material capable of forming a channel formation region of a transistor having at least one of an amplifying function, a rectifying function, and a switching function, the metal oxide can be referred to as a metal oxide semiconductor. Furthermore, the term "OS transistor" can be rephrased as a transistor including a metal oxide or an oxide semiconductor.

[0053] In this specification and the like, nitrogen-containing metal oxides may also be collectively referred to as metal oxides. Nitrogen-containing metal oxides may also be referred to as metal oxynitrides.

[0054] In this specification and the like, the configurations shown in each embodiment can be combined as appropriate with the configurations shown in other embodiments to form one aspect of the present invention. Furthermore, when multiple configuration examples are shown in one embodiment, these configuration examples can be combined as appropriate.

[0055] The embodiments described herein will be described with reference to the drawings. However, the embodiments can be implemented in many different ways. Therefore, those skilled in the art will readily understand 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 construed as being limited to the description of the embodiments. In the drawings illustrating the embodiments, the same reference numerals may be used in different drawings to designate identical or similarly functional parts in the configuration of the invention, thereby avoiding repetitive description. Furthermore, in the drawings, the same hatching patterns may be used and no particular reference numerals may be used to indicate similar functions. Furthermore, for ease of understanding, the drawings may omit the illustration of some components, for example, in perspective views or top views. Furthermore, the drawings may omit notations such as hatching patterns.

[0056] In addition, in the drawings and the like relating to this specification, the size, layer thickness, or region may be exaggerated for clarity. Therefore, the drawings are not necessarily limited to, for example, their size or aspect ratio. Note that the drawings are schematic illustrations of ideal examples and are not limited to, for example, the shapes or values ​​shown in the drawings. For example, variations in signal, voltage, or current due to noise, or variations in signal, voltage, or current due to timing deviations, etc. may be included.

[0057] In addition, in drawings and the like relating to this specification, arrows indicating the X direction, Y direction, and Z direction may be used. In this specification and the like, the "X direction" refers to the direction along the X axis, and the forward direction and the reverse direction may not be distinguished unless explicitly stated. The same applies to the "Y direction" and the "Z direction." The X direction, Y direction, and Z direction are directions that intersect with each other. More specifically, the X direction, Y direction, and Z direction are directions that are perpendicular to each other. In this specification and the like, one of the X direction, Y direction, and Z direction may be referred to as the "first direction" or "first direction." The other may be referred to as the "second direction" or "second direction." The remaining one may be referred to as the "third direction" or "third direction."

[0058] In this specification and the like, when the same reference numeral is used for multiple elements, and particularly when it is necessary to distinguish between them, the reference numeral may be accompanied by an identifying symbol such as "A", "b", "_1", "[n]", or "[m, n]". For example, multiple light-emitting elements 61 may be referred to as light-emitting element 61R, light-emitting element 61G, or light-emitting element 61B. In other words, when describing matters common to light-emitting element 61R, light-emitting element 61G, and light-emitting element 61B, or when there is no need to distinguish between them, they may be simply referred to as "light-emitting element 61".

[0059] Embodiment 1 An electronic device 100 according to one embodiment of the present invention will be described.

[0060] <Configuration Example of Electronic Device> Fig. 1A is a perspective external view illustrating a configuration example of electronic device 100. Electronic device 100 may be applied to, for example, a goggle-type electronic device for virtual reality (VR) applications. Electronic device 100 includes a housing 101. Electronic device 100 also includes a belt-like attachment unit 103. The length of attachment unit 103 is adjustable as appropriate. A user of electronic device 100 can wear attachment unit 103 around and on the top of their head to look inside housing 101.

[0061] The electronic device 100 also includes an optical device 13 (optical device 13R and optical device 13L) inside the housing 101. The optical device 13 further includes a display device 10 (display device 10R and display device 10L), a light source 11 (light source 11R and light source 11L), and an optical system 12 (optical system 12R and optical system 12L). Detailed descriptions of configuration examples of the optical device 13, the display device 10, the light source 11, and the optical system 12 will be given later.

[0062] Electronic device 100 also includes sensor unit 50, sensor unit 51 (sensor unit 51R and sensor unit 51L), a power supply unit (battery 104 and voltage generation unit 105), control unit 106, communication unit 107, and antenna 108. For example, electronic device 100 includes sensor unit 50, sensor unit 51, battery 104, voltage generation unit 105, control unit 106, and communication unit 107 in housing 101, and antenna 108 in attachment unit 103.

[0063] The electronic device 100 also includes earphones 121 (earphones 121R and 121L). Instead of the earphones 121, a bone conduction acoustic device 122 (acoustic device 122R and 122L) may be included. The electronic device 100 may include either or both of the earphones 121 and the bone conduction acoustic device 122. For example, the electronic device 100 includes the bone conduction acoustic device 122 in the attachment unit 103. The use of the bone conduction acoustic device 122 allows the user to simultaneously hear the acoustic signal transmitted from the electronic device 100 and the surrounding sounds.

[0064] [Sensor Unit] The sensor units 50 and 51 have a function of acquiring information from, for example, one or more of the user's vision, hearing, touch, taste, and smell. More specifically, the sensor units 50 and 51 have a function of detecting or measuring, for example, one or more of force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, magnetism, temperature, sound, time, electric field, current, voltage, power, radiation, humidity, gradient, vibration, odor, and infrared light. The electronic device 100 may include one or more sensor units 50. The electronic device 100 may include one or more sensor units 51.

[0065] For example, an image sensor may be used as the sensor unit 50. By using an image sensor for the sensor unit 50, it is possible to capture, for example, a picture of the surrounding scenery. Furthermore, for example, a sensor that can measure one or more of the ambient temperature, humidity, illuminance, and odor may be used as the sensor unit 50.

[0066] Furthermore, for example, a biosensor may be used as the sensor unit 51. By using a biosensor as the sensor unit 51, for example, the user's body temperature, pulse rate, or oxygen saturation level in the blood can be measured, and the user's fatigue level or health condition can be detected.

[0067] Furthermore, at least one of the sensor unit 50 and the sensor unit 51 preferably has a function for measuring brain waves in addition to the above functions. For example, the sensor unit 50 or the sensor unit 51 may have a mechanism for measuring brain waves from a weak current flowing through a plurality of electrodes that contact the head. By providing the sensor unit 50 or the sensor unit 51 with the function for measuring brain waves, it is possible to realize an operation such as displaying an image or a portion of an image at a location on the display area where the user desires. Since the user does not need to use both hands to operate the electronic device 100, for example, the user can perform input operations without holding anything in their hands.

[0068] [Power Supply Unit] The battery 104 has a function of storing the power required for the operation of the electronic device 100 and a function of supplying the power required for the operation. The voltage generation unit 105 has a function of generating the voltage required for the operation of the electronic device 100 and a function of keeping the voltage constant. The battery 104 can be a primary battery or a secondary battery. Note that the secondary battery can be, for example, a lithium ion secondary battery. The battery 104 and the voltage generation unit 105 can be collectively referred to as a power supply unit.

[0069] 1A illustrates a configuration including the battery 104, but is not limited to this. The electronic device 100 may be configured to receive power directly from an external power source without being provided with the battery 104. Alternatively, the electronic device 100 may include the battery 104 and have a function to receive power from an external source.

[0070] [Control Unit] The control unit 106 has a function of controlling the operation of the electronic device 100. The control unit 106 can have, for example, a CPU or a memory. The memory has a function of storing, for example, various programs used by the electronic device 100 and data necessary for the operation of the electronic device 100.

[0071] The control unit 106 also has a function of supplying an image signal to the display device. The control unit 106 can also perform a process of increasing the resolution (up-conversion) or decreasing the resolution (down-conversion) of the image signal. This allows low-resolution image data to be up-converted to match the resolution of the display area (also referred to as the "display unit"), or high-resolution image data to be down-converted. This allows high-quality images to be displayed on the display device.

[0072] Furthermore, the control unit 106 may include, for example, a GPU, etc., as necessary. The control unit 106 can function as an application processor that has functions necessary for the operation of the electronic device 100.

[0073] The communication unit 107 has a function of communicating with, for example, another terminal wirelessly or via a wire. In particular, if the communication unit 107 has a function of communicating wirelessly, it is preferable because, for example, the number of components such as cables for connection can be reduced.

[0074] If the communication unit 107 has a function of wireless communication, the communication unit 107 can communicate via the antenna 108. Furthermore, as a communication protocol or communication technology, for example, a communication standard such as LTE (Long Term Evolution), or a communication specification standardized by IEEE, such as Wi-Fi (registered trademark), Bluetooth (registered trademark), or ZigBee (registered trademark), can be used. Furthermore, for example, a third-generation mobile communication system (3G), a fourth-generation mobile communication system (4G), or a fifth-generation mobile communication system (5G) defined by the International Telecommunication Union (ITU) can also be used.

[0075] The communication unit 107 can connect the electronic device 100 to other devices and input and output information via a computer network such as the Internet, an intranet, an extranet, a PAN (Personal Area Network), a LAN (Local Area Network), a CAN (Campus Area Network), a MAN (Metropolitan Area Network), a WAN (Wide Area Network), or a GAN (Global Area Network), which is the foundation of the World Wide Web (WWW).

[0076] 1A shows an example in which the electronic device 100 includes one antenna 108, but the present invention is not limited to this and the electronic device 100 may include multiple antennas. By including multiple antennas, the stability of wireless communication can be improved.

[0077] The communication unit 107 may also be electrically connected to an external port (not shown) provided on the electronic device 100. The external port may be configured to connect to an external device such as a computer or a printer via a cable. A typical example is a USB terminal. The external port may also include a terminal for connecting to a local area network (LAN), a terminal for receiving digital broadcasts, or a terminal for connecting an AC adapter. In addition to wired communication, the electronic device 100 may also be configured to include a transceiver for optical communication using, for example, infrared light, visible light, or ultraviolet light. The communication unit 107 may also be electrically connected to, for example, one or more buttons or switches (also referred to as "casing switches"; not shown) provided on the electronic device 100.

[0078] [Optical Device] A description will be given of an example of the internal configuration of the housing 101 provided in the electronic device 100. Fig. 1B is a schematic diagram of the inside of the housing 101 as viewed from above.

[0079] The electronic device 100 includes, inside a housing 101, an optical device 13R that can be used for the right eye and an optical device 13L that can be used for the left eye. The optical device 13R includes a display device 10R, a light source 11R, and an optical system 12R. The display device 10R includes a display region 60R and a sensor region 52R. The optical system 12R includes a mirror 21R, a mirror 22R, and a lens 23R. The optical device 13L includes a display device 10L, a light source 11L, and an optical system 12L. The display device 10L includes a display region 60L and a sensor region 52L. The optical system 12L includes a mirror 21L, a mirror 22L, and a lens 23L.

[0080] In this embodiment, the optical device 13R for the right eye and the optical device 13L for the left eye are separately provided inside the housing 101, but this is not limiting. For example, a portion of the display device may be used for the right eye and a portion for the left eye. Also, for example, a light source may be shared between the right eye and the left eye. Also, for example, a portion of the optical system may be shared between the right eye and the left eye. In this way, it may be difficult to separate the right eye and the left eye. Also, the display device, light source, and optical system may have the same configuration for the right eye and the left eye.

[0081] The electronic device 100 is configured to block external light from entering the housing 101, providing a highly immersive experience for the user. The electronic device 100 also includes a sensor unit 50 at the front of the housing 101. The sensor unit 50 may capture images of the surrounding scenery using an imaging element and display the images on one or both of the display devices 10R and 10L. The electronic device 100 can also display other information superimposed on the image of the surrounding scenery. Therefore, the electronic device 100 can also function as a wearable electronic device for augmented reality (AR) applications.

[0082] <Configuration Example of Optical Device> A configuration example of the optical device 13 will be described. Fig. 2 is a schematic diagram of the optical device 13 as seen from the side. The optical device 13 includes a display device 10, a light source 11, an optical system 12, and a housing 14. Note that Fig. 2 also illustrates an eyeball 20 of a user of the electronic device 100. The optical device 13 can be applied to both the optical device 13R for the right eye and the optical device 13L for the left eye provided in the electronic device 100.

[0083] The optical system 12 is covered by a housing 14 and is provided between the eyeball 20 and the display device 10. The housing 14 is provided with an opening 14a on the display device 10 side and an opening 14b on the eyeball 20 side. The housing 14 has a function of blocking light except for the openings 14a and 14b. The light source 11 may also be provided, for example, around the opening 14b of the housing 14.

[0084] The housing 14 is not limited to a truncated cone shape as shown in Fig. 2 as long as it has a function of blocking light from areas other than the openings 14a and 14b. The housing 14 can have an appropriate shape to match the display device 10 and the optical system 12. For example, the housing 14 may have a truncated cone shape, a truncated square pyramid shape, a cylinder shape, a square prism shape, or a combination of these shapes.

[0085] 3 is a schematic diagram for explaining an example of the configuration of the optical system 12. Note that an eyeball 20 of the user of the electronic device 100 is illustrated in FIG.

[0086] [Light Source] The light source 11 has a function of emitting light 32 and irradiating the eyeball 20. The light 32 is preferably other than visible light. Furthermore, the light 32 preferably includes infrared light. That is, the light source 11 has a function of emitting infrared light. Specifically, the light source 11 has a function of emitting light with a wavelength of 780 nm to 3000 nm, preferably 780 nm to 2500 nm. Light with such wavelengths is not visible to the user and is therefore preferable because it does not obstruct the visibility of images displayed on the display device. Note that light with a wavelength of 780 nm to 3000 nm may be referred to as infrared light, and light with a wavelength of 780 nm to 2500 nm may be referred to as near-infrared light. While it is often described that the light source 11 emits infrared light, near-infrared light may also be emitted. For example, a wavelength of 830 nm to 870 nm is preferable for line-of-sight detection. The light source 11 may be, for example, a light-emitting diode (sometimes referred to as LED).

[0087] [Display Device] The display device 10 includes a display area 60 and a sensor area 52. The display area 60 and the sensor area 52 are each provided so that, when the display device 10 and the housing 14 are overlapped, a part or all of the display area 60 and the sensor area 52 are included in an opening (corresponding to the opening 14a in FIG. 2 ) on the display device 10 side of the housing 14. Furthermore, the sensor area 52 is preferably provided so as to be located below the display area 60 when the user views the display device 10 through the optical system 12.

[0088] The display area 60 has a function of displaying an image. Specifically, the display area 60 has light-emitting elements, and the image is displayed by light 31 emitted by the light-emitting elements. Therefore, the light 31 emitted from the display area 60 includes visible light. The light 31 is irradiated onto the eyeball 20 via the optical system 12. This allows the user to view the image.

[0089] The sensor area 52 has a function of detecting, via the optical system 12, light incident from an opening (corresponding to the opening 14b in FIG. 2 ) on the eyeball 20 side of the housing 14. The light detected by the sensor area 52 is preferably, for example, infrared light. For example, the sensor area 52 can detect light 33 that is reflected by the eyeball 20 out of the light 32 emitted from the light source 11. In other words, it can capture an image of the eyeball 20 irradiated with infrared light emitted from the light source 11.

[0090] The object imaged by the sensor region 52 is not limited to the eyeball 20, but may be an area wider than the eyeball 20, including, for example, the user's eyeball or eyelid. The sensor region 52 may also be used to measure, for example, the number of blinks, eyelid behavior, changes in pupil size, or gaze behavior, to detect, for example, the user's fatigue level and health condition. Furthermore, by appropriately combining this information with information obtained from the sensor unit 51 described above, the detection accuracy can be improved.

[0091] Furthermore, by detecting the user's gaze, it is possible to know the user's focus point. For example, by combining the detection of the focus point and the measurement of the number of blinks per unit time, it is possible to select an icon displayed in the display area of ​​the display device 10. That is, it is possible to realize the operation of clicking an icon with a mouse by detecting the user's gaze and eyelid movements. That is, it is possible to control the operation of the electronic device 100 by detecting the user's gaze and eyelid movements. Because the user does not need to use both hands to operate the electronic device 100, for example, the user can perform input operations without holding anything in their hands.

[0092] The sensor region 52 may be provided separately from the display region 60, or may be provided overlapping the display region 60. For example, as shown in Fig. 4A , by providing the sensor region 52 and the display region 60 separately, the influence of light emitted from the display region 60 on the sensor region 52 can be reduced. Furthermore, as shown in Fig. 4B , by providing the sensor region 52 and the display region 60 overlapping each other, the sensor region 52 can function as the display region 60 except for the period when it is detecting the light 33 as the sensor region 52, thereby ensuring a wide image display region.

[0093] A more detailed configuration example of the display device 10 will be described later.

[0094] [Optical System] The optical system 12 has a function of appropriately controlling the optical path so that light 31 emitted from the display area 60 in the display device 10 is incident on the eyeball 20. It also has a function of appropriately controlling the optical path so that light 33 reflected by the eyeball 20 is incident on the sensor area 52 in the display device 10.

[0095] The optical system 12 includes one or more optical elements, such as one or more elements selected from a lens, a prism, a mirror, a filter, and a diffraction grating.

[0096] The optical system 12 includes, for example, a mirror 21 and a mirror 22. The mirror 21 can be provided on the optical path of the light 31. The mirror 21 preferably has the function of transmitting visible light and reflecting infrared light. Such a mirror is called a hot mirror. For example, in the present embodiment and the like, the light 31 includes visible light. Therefore, the light 31 incident on one surface (sometimes referred to as the first surface) of the mirror 21 is transmitted to the other surface (sometimes referred to as the second surface) of the mirror 21. Furthermore, in the present embodiment and the like, when the eyeball 20 is irradiated with light 32 including infrared light, the light 33 reflected by the eyeball 20 includes infrared light. Therefore, the light 33 incident on the other surface (the second surface) of the mirror 21 is reflected.

[0097] The mirror 21 is provided between the display area 60 and the eyeball 20. The optical system 12 may also include a lens 23. The lens 23 is provided between the mirror 21 and the eyeball 20. For example, the lens 23 may be provided in the opening 14b. Thus, light 31 emitted from the display area 60 passes through the mirror 21 and the lens 23 in this order, and reaches the eyeball 20.

[0098] Furthermore, mirror 22 can be provided on the optical path of light 33. Light 33 passes through lens 23, enters the other surface (second surface) of mirror 21, and is reflected. Light 33 reflected by the other surface (second surface) of mirror 21 is further reflected by mirror 22 and reaches sensor area 52. In other words, mirror 22 is provided so that light 33 is reflected by mirror 21 and then mirror 22 and enters sensor area 52.

[0099] Note that the optical system that can be used in the optical device according to one embodiment of the present invention is not limited to the configuration example shown in FIG. 3 . While FIG. 3 illustrates an example in which plane mirrors are used as the mirrors 21 and 22, the present invention is not limited thereto. For example, a concave mirror or a convex mirror may also be used. Furthermore, for example, a spherical lens, an aspherical lens, or a Fresnel lens may be used as the lens 23. By appropriately selecting these lenses, the optical path can be appropriately controlled so that light 31 emitted from the display region 60 forms an image on the eyeball 20 and light 33 reflected by the eyeball 20 forms an image on the sensor region 52.

[0100] Furthermore, in order to appropriately control the optical paths of the light 31 and the light 33, one or more optical elements can be used in appropriate combination. For example, as another configuration example of the optical system 12, as shown in FIG. 5 , the plane mirror 21 may be replaced with a concave mirror 24, and a lens 25 may be provided between the mirror 22 and the sensor area 52. The lens 25 may be provided in the optical system 12 or in the display device 10. As an example, FIG. 6 shows a schematic diagram in which the lens 25 is provided on the sensor area 52 of the display device 10. As the lens 25, for example, a microlens, a pinhole, or the like may be provided on the sensor area 52.

[0101] <Modifications of the Configuration of the Optical Device> The configuration of the optical device 13 is not limited to the example shown in FIG. 2 . For example, an optical element may be provided between the light source 11 and the eyeball 20. For example, by providing a filter that cuts visible light between the light source 11 and the eyeball 20, it is possible to irradiate the eyeball 20 with only infrared light even when the light 32 emitted by the light source 11 contains visible light components. This improves the visibility of the image. Furthermore, for example, by providing a lens between the light source 11 and the eyeball 20, it is possible to efficiently irradiate the light 32 emitted by the light source 11 onto the eyeball 20. This makes it possible to obtain clearer imaging data when imaging the eyeball 20 using the sensor area 52.

[0102] The position where the light source 11 is provided is not limited to the periphery of the opening 14b of the housing 14. For example, the light source 11 may be provided in the display device 10. Furthermore, other than an LED, a light-emitting element having a function of emitting infrared light (for example, an organic electroluminescence element) may be used as the light source 11.

[0103] For example, as shown in Figures 7 and 8, light sources 11 may be provided around the display area 60 and sensor area 52 of the display device 10. Note that Figure 8A is a schematic diagram of a case where the sensor area 52 and the display area 60 are provided separately, and Figure 8B is a schematic diagram of a case where the sensor area 52 is provided within the display area 60. By providing the light sources 11 in the display device 10, it is possible to reduce the space required for the electronic device 100. In other words, it is possible to reduce the size and weight of the electronic device 100.

[0104] Furthermore, an optical element may be provided between the light source 11 and the eyeball 20. For example, by providing a mirror between the light source 11 and the eyeball 20, the light 32 emitted by the light source 11 can be efficiently irradiated onto the eyeball 20.

[0105] <Configuration Example of Peripheral Circuits of Display Area and Sensor Area> A configuration example of the display device 10 will be described. Fig. 9 is a block diagram illustrating the display device 10. The display device 10 includes a display area 60, a sensor area 52, a peripheral circuit area 232, a peripheral circuit area 233, a peripheral circuit area 292, and a peripheral circuit area 293.

[0106] The circuits included in the peripheral circuit region 232 function, for example, as a scanning line driving circuit for the display region 60. The circuits included in the peripheral circuit region 233 function, for example, as a signal line driving circuit for the display region 60. The circuits included in the peripheral circuit region 292 function, for example, as a row signal line driving circuit for the sensor region 52. The circuits included in the peripheral circuit region 293 function, for example, as a readout circuit for the sensor region 52. The circuits included in the peripheral circuit region 232, the peripheral circuit region 233, the peripheral circuit region 292, and the peripheral circuit region 293 may be collectively referred to as a "peripheral driving circuit."

[0107] The peripheral driver circuit can be formed using various circuits such as a shift register, a level shifter, an inverter, a latch, an analog switch, a logic circuit, a source follower, an operational amplifier, or an amplifier circuit. The peripheral driver circuit can be formed using, for example, a transistor or a capacitor. The transistors included in the peripheral driver circuit can be formed using the same process as the transistors included in the pixel 230 and the pixel 290.

[0108] The display device 10 also has m (m is an integer of 1 or more) wirings 236 that are arranged substantially parallel to one another and whose potentials are controlled by circuits included in the peripheral circuit region 232, and n (n is an integer of 1 or more) wirings 237 that are arranged substantially parallel to one another and whose potentials are controlled by circuits included in the peripheral circuit region 233. The display device 10 also has p (p is an integer of 1 or more) wirings 296 that are arranged substantially parallel to one another and whose potentials are controlled by circuits included in the peripheral circuit region 292, and q (q is an integer of 1 or more) wirings 297 that are arranged substantially parallel to one another and whose potentials are controlled by circuits included in the peripheral circuit region 293.

[0109] The display region 60 has a plurality of pixels 230 arranged in a matrix. For example, a pixel 230 that controls the amount of red light emitted, a pixel 230 that controls the amount of green light emitted, and a pixel 230 that controls the amount of blue light emitted can be collectively configured to function as a single pixel, and the amount of light emitted (luminance) 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 amount of red light, green light, or blue light emitted. The color of light controlled by each of the three subpixels is not limited to a combination of red (R), green (G), and blue (B), but may also be cyan (C), magenta (M), and yellow (Y).

[0110] Furthermore, four subpixels may be combined to function as one pixel. For example, a subpixel that controls the amount of white light may be added to three subpixels that control the amount of red, green, and blue light emitted, respectively. By adding a subpixel that controls the amount of white light emitted, the luminance of the display area can be increased. Furthermore, a subpixel that controls the amount of yellow light may be added to three subpixels that control the amount of red, green, and blue light emitted, respectively. Furthermore, a subpixel that controls the amount of white light may be added to three subpixels that control the amount of cyan, magenta, and yellow light emitted, respectively.

[0111] By increasing the number of sub-pixels that function as one pixel and appropriately combining sub-pixels that control the amount of light emitted, such as red, green, blue, cyan, magenta, and yellow, it is possible to improve the reproducibility of intermediate tones and thus the display quality.

[0112] Furthermore, 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.21 standard used in high definition television (HDTV). It is possible to reproduce color gamuts such as those of 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).

[0113] The resolution of the display area 60 can be, for example, HD (1280 x 720 pixels), FHD (1920 x 1080 pixels), or WQHD (2560 x 1440 pixels). Furthermore, it is preferable to have an extremely high resolution such as WQXGA (2560 x 1600 pixels), 4K2K (3840 x 2160 pixels), or 8K4K (7680 x 4320 pixels). 4K2K, 8K4K, or higher resolutions are particularly preferable.

[0114] The pixel density (resolution) of the display area 60 is preferably 1000 ppi or more and 10000 ppi or less, but may be, for example, 2000 ppi or more and 6000 ppi or less, or 3000 ppi or more and 5000 ppi or less.

[0115] There are no particular limitations on the screen ratio (aspect ratio) of the display area 60. The display area 60 of the display device 10 can accommodate various screen ratios, such as 1:1 (square), 4:3, 16:9, or 16:10.

[0116] Furthermore, a display device according to one embodiment of the present invention can vary its 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. Driving the display device at a reduced refresh rate to reduce power consumption may be referred to as idling stop (IDS) driving.

[0117] The sensor region 52 has a plurality of pixels 290 arranged in a matrix. The pixels 290 have a function of outputting a signal according to the amount of light received.

[0118] The resolution of the sensor area 52 can be set appropriately according to the size of the eyeball 20. The resolution of the sensor area 52 may be, for example, 200×200 pixels, 400×400 pixels, or 640×480 pixels.

[0119] The sensor region 52 can also be provided within the display region 60 (see FIG. 4B ). That is, for example, the pixel 290 and the three pixels 230 can each be a sub-pixel, and the four sub-pixels can be combined into one pixel. In the display region 60, the three pixels 230 can be made to function to achieve full-color display. In the sensor region 52, the pixel 290 can be made to function to achieve the function of outputting a signal corresponding to the amount of received light.

[0120] Furthermore, in the sensor region 52, for example, during the period when the amount of received light is detected, the function of the three pixels 230 is stopped and light emission is stopped, thereby reducing the influence of the pixels 230 on the pixels 290.

[0121] 10A is a diagram showing an example of a circuit configuration of a pixel 230 included in the display region 60. The pixel 230 includes a pixel circuit 431 and a light-emitting element 432.

[0122] Each wiring 236 is electrically connected to n pixel circuits 431 arranged in any row among the pixel circuits 431 arranged in m rows and n columns in the display region 60. Furthermore, each wiring 237 is electrically connected to m pixel circuits 431 arranged in any column among the pixel circuits 431 arranged in m rows and n columns. Both m and n are integers of 1 or greater.

[0123] The pixel circuit 431 includes a transistor 436, a capacitor 433, a transistor 438, and a transistor 434. The pixel circuit 431 is electrically connected to a light-emitting element 432.

[0124] In this specification and elsewhere, the term “element” may be replaced with “device.” For example, a display element, a light-emitting element, and a liquid crystal element may be replaced with a display device, a light-emitting device, and a liquid crystal device.

[0125] One of the source and the drain of the transistor 436 is electrically connected to a wiring (hereinafter referred to as a signal line DL_n) to which a data signal (also referred to as a "video signal") is supplied. Furthermore, the gate of the transistor 436 is electrically connected to a wiring (hereinafter referred to as a scan line GL_m) to which a gate signal is supplied. The signal line DL_n and the scan line GL_m correspond to the wiring 237 and the wiring 236, respectively.

[0126] The transistor 436 has a function of controlling writing of a data signal to the wiring 435 .

[0127] One of a pair of electrodes of the capacitor 433 is electrically connected to a wiring 435, and the other is electrically connected to a wiring 437. The other of the source and the drain of the transistor 436 is electrically connected to the wiring 435.

[0128] The capacitor 433 functions as a storage capacitor that holds data written to the wiring 435 .

[0129] One of the source and the drain of the transistor 438 is electrically connected to the potential supply line VL_a, and the other is electrically connected to the wiring 437. Further, a gate of the transistor 438 is electrically connected to the wiring 435.

[0130] One of the source and the drain of the transistor 434 is electrically connected to the potential supply line V0, and the other is electrically connected to a wiring 437. Furthermore, a gate of the transistor 434 is electrically connected to the scan line GL_m.

[0131] One of the anode and the cathode of the light-emitting element 432 is electrically connected to the potential supply line VL_b, and the other is electrically connected to a wiring 437 .

[0132] For example, an organic electroluminescence element (also referred to as an organic EL element) can be used as the light-emitting element 432. However, the light-emitting element 432 is not limited to this, and for example, an inorganic EL element made of an inorganic material may also be used. Note that "organic EL elements" and "inorganic EL elements" may be collectively referred to as "EL elements."

[0133] The luminescent color of the EL element can be, for example, white, red, green, blue, cyan, magenta, or yellow, depending on the material that constitutes the EL element.

[0134] There are two methods for achieving color display: combining a light-emitting element 432 that emits white light with a colored layer, and providing light-emitting elements 432 that emit different colors for each pixel. The former method has higher productivity than the latter method. On the other hand, the latter method is less productive than the former method because it requires creating a different light-emitting element 432 for each pixel. However, the latter method can obtain an emitted color with higher color purity than the former method. In addition to the latter method, the color purity can be further improved by providing a microcavity structure to the light-emitting element 432.

[0135] Both low molecular weight compounds and high molecular weight compounds can be used for the light emitting element 432, and an inorganic compound may also be included. Each layer constituting the light emitting element 432 can be formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, or a coating method.

[0136] The light-emitting element 432 may include an inorganic compound (such as quantum dots). For example, quantum dots can be used in the light-emitting layer to function as a light-emitting material.

[0137] The power supply potential may be, for example, a relatively high power supply potential or a relatively low power supply potential. The high power supply potential may be referred to as a high power supply potential VDD1, and the low power supply potential may be referred to as a low power supply potential VSS1. For example, the high power supply potential VDD1 is applied to one of the potential supply line VL_a or the potential supply line VL_b, and the low power supply potential VSS1 is applied to the other.

[0138] For example, the ground potential can be used as the high power supply potential or the low power supply potential. For example, when the high power supply potential is the ground potential, the low power supply potential is a potential lower than the ground potential, and when the low power supply potential is the ground potential, the high power supply potential is a potential higher than the ground potential.

[0139] In a display device having the pixel circuits 431 , the pixel circuits 431 in each row are sequentially selected by a circuit included in a peripheral driver circuit, and the transistors 436 and 434 are turned on to write a data signal to the wiring 435 .

[0140] The pixel circuit 431 in which data is written to the wiring 435 is brought into a holding state by turning off the transistor 436 and the transistor 434. Furthermore, the amount of current flowing between the source and drain of the transistor 438 is controlled in accordance with the potential of the data written to the wiring 435, and the light-emitting element 432 emits light with a luminance corresponding to the amount of current flowing. By performing this process sequentially for each row, an image can be displayed.

[0141] 10B is a diagram showing an example of the circuit configuration of a pixel 290 included in the sensor region 52. The pixel 290 includes a pixel circuit 491 and a light receiving element 492.

[0142] Each wiring 296 is electrically connected to q pixel circuits 491 arranged in any row among the pixel circuits 491 arranged in p rows and q columns in the sensor region 52. Furthermore, each wiring 297 is electrically connected to p pixel circuits 491 arranged in any column among the pixel circuits 491 arranged in p rows and q columns. Both p and q are integers greater than or equal to 1.

[0143] The pixel circuit 491 includes a transistor 496, a transistor 493, a transistor 498, and a transistor 494. The pixel circuit 491 is electrically connected to a light-receiving element 492.

[0144] In this specification and the like, the term “element” may be replaced with “device.” For example, a light-receiving element may be replaced with a light-receiving device.

[0145] One of the source and the drain of the transistor 496 is electrically connected to a wiring 499, and the other is electrically connected to a wiring 495. Furthermore, a gate of the transistor 496 is electrically connected to a wiring to which a first row selection signal is applied (hereinafter referred to as a row selection line TX_p).

[0146] The transistor 496 has a function of controlling transfer of charge between the wiring 499 and the wiring 495 .

[0147] One of the source and the drain of the transistor 493 is electrically connected to the potential supply line VL_c, and the other is connected to a wiring 495. Furthermore, a gate of the transistor 493 is electrically connected to a wiring to which a second row selection signal is applied (hereinafter referred to as a row selection line RS_p).

[0148] One of the source and the drain of the transistor 498 is electrically connected to the potential supply line VL_e, and the other is connected to a wiring 497. A gate of the transistor 498 is electrically connected to a wiring 495.

[0149] One of the source and the drain of the transistor 494 is electrically connected to a wiring (hereinafter referred to as a signal line WX_q) that reads out a detection signal, and the other is connected to a wiring 497. Furthermore, a gate of the transistor 494 is electrically connected to a wiring (hereinafter referred to as a row selection line SE_p) that receives a third row selection signal.

[0150] The wiring group of the row selection line TX_p, the row selection line RS_p, and the row selection line SE_p corresponds to the wiring 296. The signal line WX_q corresponds to the wiring 297.

[0151] One of the anode and the cathode of the light-receiving element 492 is electrically connected to the potential supply line VL_d, and the other is electrically connected to a wiring 499 .

[0152] For example, a photoelectric conversion element (also called an organic photodiode, organic light receiving element, or OPD element) made of an organic material can be used as the light receiving element 492. However, the light receiving element 492 is not limited to this, and for example, a photoelectric conversion element (also called a photodiode or photodetector) made of an inorganic material may also be used.

[0153] The power supply potential may be, for example, a relatively high power supply potential or a relatively low power supply potential. The high power supply potential may be referred to as a high power supply potential VDD2, and the low power supply potential may be referred to as a low power supply potential VSS2. A power supply potential relatively higher than the high power supply potential VDD2 may be referred to as a high power supply potential VDD3. For example, the high power supply potential VDD2 is applied to one of the potential supply line VL_c or the potential supply line VL_d, and the low power supply potential VSS2 is applied to the other. For example, the high power supply potential VDD3 is applied to the potential supply line VL_e.

[0154] For example, the high power supply potential VDD2 or the low power supply potential VSS2 may be the same as the low power supply potential VSS1.

[0155] In a display device having the pixel circuits 491, one or more rows of pixel circuits 491 are sequentially selected by a circuit included in a peripheral driver circuit to perform imaging and readout.

[0156] When imaging, first, the transistor 493 and the transistor 496 are turned on, and the potential applied to the potential supply line VL_c is supplied to the wiring 499 (this is also referred to as initialization). Next, the transistor 493 and the transistor 496 are turned off, so that charges corresponding to the amount of light received by the light-receiving element 492 are gradually accumulated in the wiring 499 (this is also referred to as exposure). Next, after a given time (exposure time) has elapsed, the transistor 496 is turned on, so that the charges accumulated in the wiring 499 are transferred (this is also referred to as transfer) to the wiring 495. Then, the potential of the wiring 495 becomes a value corresponding to the amount of light received by the light-receiving element 492. Finally, the transistor 496 is turned off, so that imaging is completed.

[0157] When reading, the transistor 494 is turned on, and a current corresponding to the potential of the wiring 495 flows through the signal line WX_q. That is, a current corresponding to the amount of light received by the light-receiving element 492 flows. This current is detected by a circuit included in the peripheral circuit region 293. By performing this for each row, the captured signal can be read out.

[0158] Note that some or all of the transistors constituting the pixel circuits 431 and 491 may be transistors having back gates. For example, some or all of the transistors constituting the pixel circuits 431 and 491 may be transistors having back gates, and the back gates may be electrically connected to the gates. Alternatively, some or all of the transistors constituting the pixel circuits 431 and 491 may be transistors having back gates, and the back gates may be electrically connected to either the source or the drain of the transistors.

[0159] <Specific Configuration Example of Display Device> FIG. 11 is a block diagram showing a configuration example of the display device 10. In addition to the display area 60, sensor area 52, peripheral circuit area 232, peripheral circuit area 233, peripheral circuit area 292, and peripheral circuit area 293 described above, the display device 10 may also include a functional circuit area 234. By including the functional circuit area 234, the display device 10 can realize various functions, such as image data generation and gaze detection. The functional circuit area 234 includes, for example, a CPU, a GPU, and a memory circuit. Furthermore, the functional circuit area 234 can be provided with one or more functional circuits for each element that realizes a function. FIG. 11 shows the control unit 130, the calculation unit 140, the memory unit 150, the input / output unit 160, and the gaze detection unit 170 as examples of functional circuits provided in the functional circuit area 234. The control unit 130 , the calculation unit 140 , the storage unit 150 , the input / output unit 160 , and the line-of-sight detection unit 170 are electrically connected to each other via a bus line 131 .

[0160] [Control Unit] The control unit 130 has a function of controlling the overall operation of the display device 10. The control unit 130 controls the operation of each of the display area 60, the peripheral circuit area 232, the peripheral circuit area 233, the sensor area 52, the peripheral circuit area 292, the peripheral circuit area 293, the calculation unit 140, the memory unit 150, the input / output unit 160, and the line-of-sight detection unit 170.

[0161] The calculation unit 140 has a function of performing calculations related to the overall operation of the display device 10, and may be, for example, a central processing unit (CPU). The calculation unit 140 has a function of generating an image to be displayed in the display area 60.

[0162] In addition to a CPU, other microprocessors such as a DSP (Digital Signal Processor) or a GPU (Graphics Processing Unit) can be used alone or in combination as the calculation unit 140. These microprocessors may also be implemented as a PLD (Programmable Logic Device), such as an FPGA (Field Programmable Gate Array) or an FPAA (Field Programmable Analog Array).

[0163] The calculation unit 140 also includes a neural network 141. The neural network 141 may be configured using software. The neural network 141 may be one or more of a deep neural network, a convolutional neural network, a recurrent neural network, an autoencoder, a deep Boltzmann machine, and a deep belief network.

[0164] The calculation unit 140 performs various data processing and program control by interpreting and executing instructions from various programs using a processor. The programs that can be executed by the processor may be stored in a memory area of ​​the processor or may be stored in the storage unit 150.

[0165] The computing unit 140 may have a main memory, which may include a volatile memory such as a random access memory (RAM) or a non-volatile memory such as a read only memory (ROM).

[0166] The RAM provided in the main memory may be, for example, a dynamic random access memory (DRAM), and a virtual memory space is allocated to and used as a working space for the calculation unit 140. For example, an operating system, application programs, program modules, or program data stored in the storage unit 150 are loaded into the RAM for execution. The data, programs, and program modules loaded into the RAM are directly accessed and operated by the calculation unit 140.

[0167] On the other hand, the ROM can store data that does not need to be rewritten, such as a BIOS (Basic Input / Output System) and firmware. As the ROM, for example, a mask ROM, an OTPROM (One Time Programmable Read Only Memory), or an EPROM (Erasable Programmable Read Only Memory) can be used. Examples of EPROMs include UV-EPROMs (Ultra-Violet Erasable Programmable Read Only Memories), which allow stored data to be erased by exposure to ultraviolet light, EEPROMs (Electrically Erasable Programmable Read Only Memories), and flash memories.

[0168] [Storage Unit] The storage unit 150 may be, for example, a storage device using a non-volatile storage element such as a flash memory, a magnetoresistive random access memory (MRAM), a phase change RAM (PRAM), a resistive RAM (ReRAM), or a ferroelectric RAM (FeRAM), or a storage device using a volatile storage element such as a dynamic RAM (DRAM) or a static RAM (SRAM).

[0169] The storage unit 150 stores, for example, a plurality of algorithms for upconverting image data, weighting coefficients for each algorithm, etc. The storage unit 150 may also store an image source to be displayed in the display area 60.

[0170] [Input / Output Unit] The input / output unit 160 is electrically connected to the control unit 106 of the electronic device 100. The input / output unit 160 may be electrically connected to the communication unit 107 of the electronic device 100. Information necessary for the operation of the display device 10 is supplied to the display device 10 via the input / output unit 160. The input / output unit 160 may also be electrically connected to, for example, one or more buttons or switches (also referred to as "casing switches") provided on the electronic device 100. The input / output unit 160 may also be electrically connected to an external port to which other input components can be connected.

[0171] Note that, although the present embodiment and the like show an example of a configuration in which the display device 10 has the functional circuit region 234, the present invention is not limited to this. Some or all of the functional circuits of the functional circuit region 234 may be provided outside the display device 10. For example, the storage unit 150 may not be built into the display device 10, and a storage device placed outside the display device 10 may be used as the storage unit 150. In this case, the storage unit 150 is electrically connected to the functional circuits (e.g., the calculation unit 140, etc.) of the display device 10 via the input / output unit 160. Alternatively, a communication means may be provided to exchange data wirelessly.

[0172] The gaze detection unit 170 has a function of detecting the gaze of the user using information obtained from the sensor area 52. The gaze of the user can be detected by a known gaze measurement (eye tracking) method, such as the Pupil Center Corneal Reflection (PCCR) method or the Bright / Dark Pupil Effect method.

[0173] For example, the PCCR method is a method for detecting a user's gaze from the relative position of a corneal reflection image (Purkinje image) generated when light is irradiated onto the eyeball with respect to the center position of the user's pupil. When detecting a user's gaze using the PCCR method, the sensor area 52 is used to capture images of the user's pupil and Purkinje image, and the gaze of the user can be detected by the gaze detection unit 170. Note that the gaze detection method using the gaze detection unit 170 is not limited to the above detection method. For example, the gaze detection unit 170 may have a function for detecting one or more selected from the user's cornea, iris, crystalline lens, and retina.

[0174] <Example of Image Processing> An electronic device according to one aspect of the present invention may perform image processing using one or more functional circuits provided in the functional circuit area 234. For example, the control unit 130 may identify an area in the display area 60 that overlaps with the gaze based on information about the user's gaze detected by the gaze detection unit 170, and perform image processing according to the position of the gaze.

[0175] An example of image processing according to the user's line of sight will be described. Fig. 12A shows the user's gaze point G and a first area S1 including the gaze point G, superimposed on an image displayed in a display area 60. Furthermore, a second area S2 outside the first area S1 and a third area S3 outside the second area S2 are superimposed on the image in the display area 60.

[0176] Although there are individual differences, human visual fields are classified into discriminative visual field, useful visual field, stable fixation visual field, guided visual field, and auxiliary visual field. The discriminative visual field is the area where visual functions, such as visual acuity or color discrimination, are at their best. Considering the intersection line between the user and the display area 60, the discriminative visual field refers to the area within a horizontal angle θx1 of approximately 5° from the intersection line (see FIG. 12B for angle θx1). In other words, the discriminative visual field corresponds to the first area S1 in FIG. 12A.

[0177] The effective visual field is the region in which specific information can be instantly identified by eye movement alone, and refers to the region within a horizontal angle θx2 of approximately 30° from the intersection line as the center and a vertical angle of approximately 20° (see FIG. 12B for angle θx2). In other words, the effective visual field corresponds to the second region S2 in FIG. 12A.

[0178] The stable fixation field is a region in which specific information can be discerned effortlessly with head movement. The induced field is a region in which the presence of a specific object can be discerned but the discrimination ability is low. The auxiliary field is a region in which the discrimination ability of a specific object is significantly low and the presence of a stimulus can be discerned. One or more fields selected from the stable fixation field, the induced field, and the auxiliary field correspond to the third region S3 in Figure 12A.

[0179] From the above, it can be seen that the image quality from the discriminative visual field to the effective visual field is important for an image. It is particularly important to improve the image quality of the discriminative visual field. Therefore, it is recommended that the control unit 130 perform image processing to improve the image quality of the first region S1, or the first region S1 and the second region S2, as shown in FIG. 12A. In other words, it is recommended to enhance the image of the first region S1, or the first region S1 and the second region S2. Image processing includes increasing the resolution of the image by upconversion.

[0180] Even if the same color, for example, white, is displayed across the first area S1 to the third area S3, it is preferable to use image processing to enhance the image in the first area S1, or the image in the first area S1 and the second area S2.

[0181] Furthermore, the control unit 130 can generate image data to be displayed in the display area 60 based on, for example, information from software installed in the electronic device 100, information from the sensor unit 50, the sensor unit 51, and the sensor area 52, and information obtained by the image processing. The image data is sent to the peripheral circuit area 293 via the bus line 131 and displayed in the display area 60.

[0182] <Operation Example of Electronic Device> An operation example of the electronic device of one embodiment of the present invention will be described below with reference to a flowchart shown in FIG.

[0183] The flowchart shown in FIG. 13 includes steps S210 to S213. First, in step S210, infrared light 31 is emitted from light source 11 and irradiated onto the user's eyeball 20. Next, in step S211, light 33 reflected from the eyeball 20 is captured by sensor region 52. Furthermore, in step S212, the captured image data acquired by sensor region 52 is read out by peripheral circuit region 293, and the captured image data is used to detect the user's line of sight by line-of-sight detection unit 170. Then, in step S213, a gaze point G on display region 60 is determined based on the user's line of sight. Subsequently, in step S214, the displayed image is updated to match the user's line of sight.

[0184] For example, as shown in Fig. 12, image processing can be performed to increase the resolution in the first region S1. By increasing the resolution of only that region, it is possible to reduce the load on the GPU of the calculation unit 140, for example.

[0185] It is also possible to detect the user's line of sight. By detecting the user's line of sight, it is possible to understand, for example, what the user is paying attention to, and analyze the user's behavior. It is also possible to make the avatar reproduce the user's eye movements. It is also possible to perform operations or menu selections using line of sight.

[0186] At least a portion of the configuration examples illustrated in this embodiment and the corresponding drawings can be appropriately combined with other configuration examples, other drawings, and other embodiments described in this specification, etc.

[0187] Embodiment 2 In this embodiment, a structural example of a display device according to one embodiment of the present invention will be described.

[0188] [Structure Example of Display Device] A structure example of a display device included in an electronic device according to one embodiment of the present invention will be described using the display device 180 illustrated in FIGS. 14A and 14B as an example.

[0189] 14A includes a substrate 181, a substrate 182, a light-emitting element 190, and a light-receiving element 191. The light-emitting element 190 includes light-emitting elements (190(R), 190(G), and 190(B)) serving as display elements and a light-emitting element (190(IR)) serving as an infrared light source, and is located on a layer 186. The light-receiving element 191 is provided on a support plate 183, the substrate 181 is provided on the light-receiving element 191, the light-emitting element 190 is provided on the substrate 181, the substrate 182 is provided on the light-emitting element 190, and a protective member 185 is provided on the substrate 182.

[0190] The light-emitting elements 190 may be configured to include, for example, a light-emitting element 190(R) that emits red light, a light-emitting element 190(G) that emits green light, a light-emitting element 190(B) that emits blue light, and a light-emitting element 190(IR) that emits infrared light. In this case, the light-emitting elements 190(R), 190(G), and 190(B) function as display elements, and the light-emitting element 190(IR) functions as an infrared light source. The number of light-emitting elements 190(IR) is not particularly limited and may be one or more. The light-emitting element 190 is disposed in a region sandwiched between the substrates 181 and 182. The substrate 181 is disposed between the support plate 183 and the light-emitting element 190, and the substrate 182 is disposed between the light-emitting element 190 and the protective member 185.

[0191] The light emitted by the light-emitting element 190 (IR) preferably includes infrared light, preferably near-infrared light. For example, infrared light having a wavelength of 700 nm or more, preferably near-infrared light having one or more peaks in the range of 800 nm to 2500 nm, can be used.

[0192] The light receiving element 191 has a function of detecting infrared light. It is preferable that the light receiving element has optical sensitivity corresponding to the infrared light, preferably near-infrared light, emitted by the light emitting element 190 (IR).

[0193] As shown in FIG. 14A , an image is displayed by the light emitted by light-emitting element 190(R), light-emitting element 190(G), and light-emitting element 190(B). Furthermore, infrared light emitted from light-emitting element 190(IR) is reflected by the user's eyeball 188, and the reflected light is detected by the light-receiving element of light-receiving element 191, thereby detecting the line of sight. Therefore, substrate 182 and protective member 185 must transmit both the visible light of light-emitting element 190(R), light-emitting element 190(G), and light-emitting element 190(B) and the infrared light reflected by light-emitting element 190(IR) and eyeball 188. Therefore, substrate 182 and protective member 185 are preferably translucent for visible light and infrared light. Furthermore, infrared light reflected by eyeball 188 must pass through substrate 181. Therefore, substrate 181 is preferably translucent for at least infrared light.

[0194] Substrates 181 and 182 may each be made of an insulator such as glass, quartz, ceramics, sapphire, or stabilized zirconia (e.g., yttria-stabilized zirconia), a resin such as an insulating resin or a conductive resin, a semiconductor such as silicon, germanium, silicon carbide, silicon germanium, gallium arsenide, indium phosphide, or zinc oxide, a metal, or an alloy. The substrate on the side from which light from light-emitting element 190 is extracted is made of a material that transmits the light. Using flexible materials for substrates 181 and 182 can increase the flexibility of display device 180 and enable it to be lightweight and thin. A polarizing plate may also be used for substrate 181 or 182.

[0195] Substrates 181 and 182 may each be made of, for example, a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (e.g., nylon or aramid), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, or cellulose nanofiber. One or both of substrates 181 and 182 may be made of glass having a thickness sufficient to provide flexibility.

[0196] 14B 。 The display device shown in FIG. 14B is different from the display device shown in FIG. 14A in that a light-emitting element 190 (IR) serving as an infrared light source is provided in the pixel portion 189. The other components are the same as those of the display device shown in FIG. 14A , and therefore the above description of FIG. 14A can be referred to for details.

[0197] As described above, in the display device 180 shown in FIGS. 14A and 14B , the layer 186 in which the light-emitting element 190 (IR) is located overlaps the light-receiving element 191. In the layer 186 in which the light-emitting element 190 is located, the light-emitting element 190 may be electrically connected to a common electrode. Therefore, light can be irradiated onto the eyeball 188 and light reflected from the eyeball 188 can be received without using a complex optical system. Furthermore, the distance between the light-emitting element 190 (IR) and the light-receiving element 191 is relatively small. Therefore, the detection sensitivity of light reflected from the eyeball 188 can be improved. Furthermore, since the optical system configuration can be simplified, the display device can be miniaturized. Note that a portion of the light-emitting element 190 (IR) may or may not overlap with the light-receiving element 191.

[0198] 15A and 15B , the light-receiving element 191 may be provided together with the light-emitting element 190 between the substrate 181 and the substrate 182. Specifically, the display device 180 illustrated in FIG. 15A differs from the display device 180 illustrated in FIG. 14A in that the light-receiving element 191 and the light-emitting element 190 are provided between the substrate 181 and the substrate 182. The display device 180 illustrated in FIG. 15B differs from the display device 180 illustrated in FIG. 14B in that the light-receiving element 191 and the light-emitting element 190 are provided between the substrate 181 and the substrate 182. In each of the display devices 180 illustrated in FIGS. 15A and 15B , the light-receiving element 191 is provided over the substrate 181. Therefore, the substrate 181 may have a low light-transmitting property or may not transmit infrared light in some cases.

[0199] In one embodiment of the present invention, the light-receiving element 191 may be provided outside the pixel portion 189. Specifically, in the display device 180 shown in FIG. 16A , the light-receiving element 191 is provided outside the pixel portion 189 together with the light-emitting element 190 (IR). In the display device 180 shown in FIG. 16B , only the light-receiving element 191 is provided outside the pixel portion 189. In the display device 180 shown in FIG. 17A , the light-receiving element 191 is provided outside the pixel portion 189 together with the light-emitting element 190 (IR). In the display device 180 shown in FIG. 17B , only the light-receiving element 191 is provided outside the pixel portion 189.

[0200] Although the above describes a configuration in which a pixel is formed using four types of light-emitting elements, namely, the light-emitting element 190(R) that emits red light, the light-emitting element 190(G) that emits green light, the light-emitting element 190(B) that emits blue light, and the light-emitting element 190(IR) that emits infrared light, one embodiment of the present invention is not limited to this. For example, a pixel may be formed using three types of light-emitting elements, namely, the light-emitting element 190(R), the light-emitting element 190(G), and the light-emitting element 190(B), by configuring the light-emitting element 190(R) to emit light having peaks in both the red wavelength and the infrared wavelength.

[0201] In addition, in the display device 180 shown in each of FIGS. 15A, 15B, 17A, and 17B, there may be cases where the support plate 183 does not need to be provided.

[0202] 14A, 14B, 16A, and 16B, a substrate may be provided instead of the support plate 183, and an insulating layer may be provided instead of the substrate 181. In this case, the light-receiving element 191 may be provided on the substrate, or the light-receiving element 191 may be formed using the substrate. Alternatively, an insulating layer may be provided on the light-receiving element 191, and the light-emitting element 190 may be provided on the insulating layer. The insulating layer is preferably translucent to at least infrared light.

[0203] In addition, in each of the display devices 180 described above, there may be cases where the protective member 185 does not need to be provided.

[0204] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification and the like.

[0205] Embodiment 3 In this embodiment, a schematic top view and a schematic cross-sectional view of a light-emitting element and its periphery included in a display device, a configuration example of the light-emitting element, a configuration example of the light-emitting element and the light-receiving element, and a configuration example of the display device will be described.

[0206] 18A is a schematic top view illustrating a configuration example in which a light-emitting element and a light-receiving element are arranged in one pixel in a display device 70 of one embodiment of the present invention. The display device 70 includes a plurality of light-emitting elements 61R that emit red light, a plurality of light-emitting elements 61G that emit green light, a plurality of light-emitting elements 61B that emit blue light, a plurality of light-emitting elements 61IR that emit infrared light, and a plurality of light-receiving elements 62.

[0207] In the following, when describing matters common to the light-emitting element 61R, the light-emitting element 61G, the light-emitting element 61B, and the light-emitting element 61IR, the symbols attached to the reference numerals may be omitted and the light-emitting element may be described as the light-emitting element 61. Alternatively, when the light-emitting element 61 is described, it may refer to one or more of the light-emitting element 61R, the light-emitting element 61G, the light-emitting element 61B, and the light-emitting element 61IR.

[0208] 18A, in order to easily distinguish between the light-emitting elements 61, the light-emitting region of each light-emitting element 61 is marked with a symbol R, G, B, or IR. Also, the light-receiving region of each light-receiving element 62 is marked with a symbol PD.

[0209] The light-emitting elements 61R, 61G, 61B, 61IR, and the light-receiving elements 62 are arranged in a matrix. Fig. 18A shows an example in which the light-emitting elements 61R, 61G, 61B, and 61IR are arranged in the X direction, with the light-receiving elements 62 arranged below them. Fig. 18A also shows an example in which the light-emitting elements 61 emitting light of the same color are arranged in the Y direction intersecting the X direction. In the display device 70 shown in Fig. 18A , a pixel 80 can be configured, for example, by sub-pixels having the light-emitting elements 61R, 61G, 61B, and 61IR arranged in the X direction, and a sub-pixel having the light-receiving element 62 disposed below these sub-pixels. The light-receiving elements 62 have the function of detecting infrared light.

[0210] 18A shows a so-called stripe arrangement in which light-emitting elements that emit light of the same color are arranged in one direction. Note that the arrangement method 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.

[0211] As the light-emitting elements 61R, 61G, 61B, and 61IR, it is preferable to use EL elements such as organic light-emitting diodes (OLEDs) or quantum-dot light-emitting diodes (QLEDs). Examples of the light-emitting material included in the light-emitting elements 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).

[0212] For example, a pn-type or pin-type photodiode can be used as the light receiving element 62. The light receiving element 62 functions as a photoelectric conversion element that detects light incident on the light receiving element 62 and generates electric charges. The amount of electric charges generated by the light receiving element 62 is determined based on the amount of light incident thereon.

[0213] In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light receiving element 62. Organic photodiodes can be easily made thin, lightweight, and large in area, and have a high degree of freedom in shape and design, making them applicable to a variety of display devices.

[0214] In one embodiment of the present invention, an organic EL element is used as the light-emitting element 61, and an organic photodiode is used as the light-receiving element 62. The organic EL element and the organic photodiode can be formed on the same substrate. Therefore, the organic photodiode can be built into a display device using the organic EL element.

[0215] Incidentally, when forming separate light-emitting layers for light-emitting elements exhibiting two different colors, a method of forming the layers by vapor deposition using a shadow mask, such as a metal mask or an FMM (fine metal mask, high-resolution metal mask), is known. Note that in this specification, elements formed in this manner may be referred to as elements with an MM (metal mask) structure. However, in elements with an MM structure, deviations from the design occur in the shape and position of the island-shaped organic film due to various influences, such as the accuracy of the metal mask, misalignment between the metal mask and the substrate, deflection of the metal mask, and the spread of the contours of the deposited film due to, for example, vapor scattering, making it difficult to achieve high definition and a high aperture ratio. Therefore, measures have been taken to artificially increase the definition (also known as pixel density), such as by applying a special pixel arrangement method, such as a pentile arrangement.

[0216] For example, the light-emitting layer is processed into a fine pattern without using a metal mask or a shadow mask such as FMM. Specifically, the light-emitting layer is processed into a fine pattern using a photolithography method. In this specification, an element formed as described above may be referred to as an element having an MML (metal maskless) structure. By using an element having an MML structure, a display device with high definition and a large aperture ratio, which have been difficult to achieve until now, can be realized. Furthermore, since the light-emitting layer can be individually fabricated, a display device with extremely vivid images, high contrast, and high display quality can be realized.

[0217] For simplicity, a case where light-emitting layers of light-emitting elements emitting two different colors of light will be described. First, a first light-emitting film and a first sacrificial film are stacked to cover two pixel electrodes. Next, a resist mask is formed on the first sacrificial film at a position overlapping one of the pixel electrodes (first pixel electrode). Next, the resist mask, a portion of the first sacrificial film, and a portion of the first light-emitting film are etched. At this time, the etching is stopped when the other pixel electrode (second pixel electrode) is exposed. As a result, a portion of the first light-emitting film (also referred to as a first light-emitting layer) processed into a strip or island shape can be formed on the first pixel electrode, and a portion of the sacrificial film (also referred to as a first sacrificial layer) can be formed thereon.

[0218] Next, a second light-emitting film and a second sacrificial film are stacked and formed. Then, resist masks are formed at positions overlapping the first pixel electrode and at positions overlapping the second pixel electrode. Subsequently, the resist mask, a portion of the second sacrificial film, and a portion of the second light-emitting film are etched in the same manner as above. As a result, a first light-emitting layer and a first sacrificial layer are provided on the first pixel electrode, and a second light-emitting layer and a second sacrificial layer are provided on the second pixel electrode. In this manner, the first light-emitting layer and the second light-emitting layer can be separately formed. Finally, the first sacrificial layer and the second sacrificial layer are removed to expose the first light-emitting layer and the second light-emitting layer, and then a common electrode is formed, thereby separately forming light-emitting elements that emit light of two different colors.

[0219] Furthermore, by repeating the above steps, it is possible to form light-emitting layers for light-emitting elements of three or more colors, thereby realizing a display device having light-emitting elements of three or four or more colors.

[0220] Here, in order to supply a potential to the common electrode, an electrode (e.g., a first electrode or a connection electrode) can be provided on the same surface as the pixel electrode and electrically connected to the common electrode. The connection electrode is disposed outside the display region where the pixels are provided. Here, in order to prevent the upper surface of the connection electrode from being exposed to etching during etching of the first light-emitting film, it is preferable to provide a first sacrificial layer on the connection electrode. Similarly, it is preferable to provide a second sacrificial layer on the connection electrode during etching of the second light-emitting film. The first sacrificial layer and the second sacrificial layer provided on the connection electrode can be removed by etching simultaneously with the first sacrificial layer on the first light-emitting layer and the second sacrificial layer on the second light-emitting layer.

[0221] For example, while it is difficult to achieve a distance of less than 10 μm between light-emitting layers exhibiting two different colors with an MM structure, the distance can be reduced to 6 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, or even 1 μm or less with an MML structure. Furthermore, by using an exposure device for LSIs, for example, the distance can be reduced to 500 nm or less, 200 nm or less, 100 nm or less, or even 50 nm or less. This significantly reduces the area of ​​the non-light-emitting region that may exist between the two light-emitting elements, enabling the aperture ratio to approach 100%. For example, the aperture ratio can be 50% or more, 60% or more, 70% or more, 80% or more, or even 90% or more, and even less than 100%.

[0222] Furthermore, the pattern of the light-emitting layer itself can be made much smaller than when a metal mask is used. For example, when a metal mask is used to create separate light-emitting layers, thickness variations occur between the center and edges of the pattern, resulting in a smaller effective area that can be used as the light-emitting region relative to the overall area of ​​the pattern. On the other hand, with the above-described fabrication method, a pattern is formed by processing a film deposited to a uniform thickness, making it possible to achieve a uniform thickness within the pattern, and even with a fine pattern, almost the entire area can be used as the light-emitting region. Therefore, the above-described fabrication method can achieve both high definition and a high aperture ratio.

[0223] In this way, according to the above-described manufacturing method, a display device integrating minute light-emitting elements can be realized, and therefore there is no need to artificially increase the resolution by applying a special pixel arrangement method such as a pen tile method. Therefore, it is possible to realize a display device with a so-called stripe arrangement in which R, G, and B are each arranged in one direction, and with a resolution of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, or even 3000 ppi or more, or even 5000 ppi or more.

[0224] 18A shows a common electrode 81 and a connection electrode 82. Here, the connection electrode 82 is electrically connected to the common electrode 81. The connection electrode 82 is provided outside the display area where the light-emitting elements 61 and the light-receiving elements 62 are arranged. Also in FIG. 18A, the common electrode 81 having an area overlapping with the light-emitting elements 61, the light-receiving elements 62, and the connection electrode 82 is shown by a dashed line.

[0225] The connection electrodes 82 can be provided along the periphery of the display area. For example, they may be provided along one side of the periphery of the display area, or they may be provided over two or more sides of the periphery of the display area. That is, when the top surface of the display area has a rectangular shape, the top surface of the connection electrodes 82 can have a strip-like shape, an L-shape, a U-shape (square bracket shape), a square shape, or the like.

[0226] Fig. 18B is a schematic top view showing an example of the configuration of display device 70, which is a modified example of display device 70 shown in Fig. 18A. Display device 70 shown in Fig. 18B differs from display device 70 shown in Fig. 18A in that light receiving elements 62 and light emitting elements 61IR are arranged alternately in the X direction.

[0227] 18B , the light-emitting elements 61R, 61G, and 61B are arranged in different rows from the light-emitting element 61IR. This allows the widths (lengths in the X direction) of the light-emitting elements 61R, 61G, and 61B to be increased, thereby increasing the brightness of the light emitted by the pixel 80.

[0228] Fig. 19A is a schematic top view showing an example of the configuration of a display device 70, which is a modified example of the display device 70 shown in Fig. 18B. The display device 70 shown in Fig. 19A differs from the display device 70 shown in Fig. 18B in that the light-emitting elements 61 are arranged in the order G, B, R in the X direction instead of the order R, G, B. The display device 70 also differs from the display device 70 shown in Fig. 18B in that the light-receiving element 62 is provided below the light-emitting elements 61G and 61B, and the light-emitting element 61IR is provided below the light-emitting element 61R.

[0229] The area occupied by the light receiving element 62 in the display device 70 shown in Fig. 19A is larger than the area occupied by the light receiving element 62 in the display device 70 shown in Fig. 18B. This increases the sensitivity of light detection by the light receiving element 62. Therefore, for example, if the display device 70 has a line of sight detection function, it can detect the line of sight with high accuracy.

[0230] Fig. 19B is a schematic top view showing an example of the configuration of display device 70, which is a modified example of display device 70 shown in Fig. 19A. Display device 70 shown in Fig. 19B differs from display device 70 shown in Fig. 19A in that light receiving element 62 is provided below light emitting element 61G, and light emitting element 61IR is provided below light emitting elements 61B and 61R.

[0231] The area occupied by the light receiving elements 62 in the display device 70 shown in FIG. 19B is smaller than the area occupied by the light receiving elements 62 in the display device 70 shown in FIG. 19A . By narrowing the area occupied by the light receiving elements 62, the light receiving range of each light receiving element 62 can be narrowed. This reduces the overlap of the light receiving ranges between different light receiving elements 62, for example, between adjacent light receiving elements 62. This prevents the image captured using the light receiving elements 62 from becoming blurred, making it difficult to capture a clear image. For the above reasons, if the display device 70 has a line of sight detection function, for example, reducing the area occupied by the light receiving elements 62 is preferable because it allows for clear imaging of the eyeball, etc., and improves authentication accuracy.

[0232] Fig. 20A is a cross-sectional view corresponding to dashed dotted line A1-A2 in Fig. 18B, Fig. 20B is a cross-sectional view corresponding to dashed dotted line B1-B2 in Fig. 18B. Fig. 20C is a cross-sectional view corresponding to dashed dotted line C1-C2 in Fig. 18B, and Fig. 20D is a cross-sectional view corresponding to dashed dotted line D1-D2 in Fig. 18B. Light-emitting element 61R, light-emitting element 61G, light-emitting element 61B, light-emitting element 61IR, and light-receiving element 62 are provided on substrate 83.

[0233] The substrate 83 may be a substrate having heat resistance sufficient to withstand at least subsequent heat treatment. When an insulating substrate is used as the substrate 83, for example, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, or an organic resin substrate may be used. Alternatively, for example, a single-crystal semiconductor substrate made of silicon, silicon carbide, or the like, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, or a semiconductor substrate such as an SOI substrate may be used. However, it is preferable to use a light-transmitting material such as a glass substrate for the substrate 83.

[0234] In particular, it is preferable to use a substrate having a semiconductor circuit including semiconductor elements such as transistors formed on the semiconductor substrate or insulating substrate as the substrate 83. The semiconductor circuit preferably constitutes, for example, a pixel circuit, a gate line driving circuit (gate driver), or a source line driving circuit (source driver). In addition to the above, for example, an arithmetic circuit, a memory circuit, or the like may also be configured.

[0235] 20A shows an example of the cross-sectional configuration of light-emitting element 61R, light-emitting element 61G, and light-emitting element 61B. Light-emitting element 61R has a pixel electrode 84R, a hole injection layer 85R, a hole transport layer 86R, a light-emitting layer 87R, an electron transport layer 88R, a common layer 89, and a common electrode 81. Light-emitting element 61G has a pixel electrode 84G, a hole injection layer 85G, a hole transport layer 86G, a light-emitting layer 87G, an electron transport layer 88G, a common layer 89, and a common electrode 81. Light-emitting element 61B has a pixel electrode 84B, a hole injection layer 85B, a hole transport layer 86B, a light-emitting layer 87B, an electron transport layer 88B, a common layer 89, and a common electrode 81.

[0236] 20B shows an example of the cross-sectional configuration of the light-emitting element 61IR and the light-receiving element 62. The light-emitting element 61IR has a pixel electrode 84IR, a hole injection layer 85IR, a hole transport layer 86IR, a light-emitting layer 87IR, an electron transport layer 88IR, a common layer 89, and a common electrode 81. The light-receiving element 62 has a pixel electrode 84PD, a hole transport layer 86PD, a light-receiving layer 90, an electron transport layer 88PD, a common layer 89, and a common electrode 81.

[0237] In the following, when describing matters common to pixel electrode 84R, pixel electrode 84G, pixel electrode 84B, pixel electrode 84IR, and pixel electrode 84PD, the symbols attached to the reference numerals may be omitted and the description may be made as pixel electrode 84. Similarly, when describing matters common to hole injection layer 85R, hole injection layer 85G, hole injection layer 85B, and hole injection layer 85IR, the symbols attached to the reference numerals may be omitted and the description may be made as hole injection layer 85. Similarly, when describing matters common to hole transport layer 86R, hole transport layer 86G, hole transport layer 86B, hole transport layer 86IR, and hole transport layer 86PD, the symbols attached to the reference numerals may be omitted and the description may be made as hole transport layer 86. Similarly, when describing matters common to light-emitting layer 87R, light-emitting layer 87G, light-emitting layer 87B, and light-emitting layer 87IR, the symbols attached to the reference numerals may be omitted and the description may be written as light-emitting layer 87. Similarly, when describing matters common to electron transport layer 88R, electron transport layer 88G, electron transport layer 88B, electron transport layer 88IR, and electron transport layer 88PD, the symbols attached to the reference numerals may be omitted and the description may be written as electron transport layer 88.

[0238] The common layer 89 functions as an electron injection layer in the light-emitting element 61. On the other hand, the common layer 89 functions as an electron transport layer in the light-receiving element 62. For this reason, the light-receiving element 62 may not necessarily have the electron transport layer 88PD.

[0239] The hole injection layer 85, the hole transport layer 86, the electron transport layer 88, and the common layer 89 can also be referred to as functional layers. The light-emitting element has a light-emitting layer between a pair of electrodes. Therefore, for example, in the light-emitting element 61 shown in FIG. 20A , the hole injection layer 85, the hole transport layer 86, the light-emitting layer 87, the electron transport layer 88, and the common layer 89 can be collectively referred to as a light-emitting layer.

[0240] The pixel electrode 84, the hole injection layer 85, the hole transport layer 86, the light-emitting layer 87, and the electron transport layer 88 can be provided separately for each element. The common layer 89 and the common electrode 81 are provided in common to the light-emitting element 61R, the light-emitting element 61G, the light-emitting element 61B, the light-emitting element 61IR, and the light-receiving element 62.

[0241] 20A, etc. The light-emitting element 61 and the light-receiving element 62 may have a hole-blocking layer and an electron-blocking layer in addition to the layers shown in Fig. 20A, etc. The light-emitting element 61 and the light-receiving element 62 may also have a layer containing, for example, a bipolar substance (a substance with high electron-transporting and hole-transporting properties).

[0242] A gap is provided between the common layer 89 and the insulating layer 92. This prevents the common layer 89 from coming into contact with the side surfaces of the light-emitting layer 87, the light-receiving layer 90, the hole transport layer 86, and the hole injection layer 85. This prevents short circuits (electrical short circuits) in the light-emitting element 61 and the light-receiving element 62.

[0243] The voids are more easily formed, for example, as the distance between the light-emitting layers 87 becomes shorter. For example, the voids can be suitably formed when the distance is 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.

[0244] 20A and other figures illustrate a configuration in which, from bottom to top, the light-emitting element 61 is provided with a pixel electrode 84, a hole injection layer 85, a hole transport layer 86, a light-emitting layer 87, an electron transport layer 88, a common layer 89 (electron injection layer), and a common electrode 81, and the light-receiving element 62 is provided with a pixel electrode 84PD, a hole transport layer 86PD, a light-receiving layer 90, an electron transport layer 88PD, a common layer 89, and a common electrode 81, but this is not a limitation of the present invention. For example, the light-emitting element 61 may be provided with, from bottom to top, a pixel electrode, an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, a hole injection layer, and a common electrode, and the light-receiving element 62 may be provided with, from bottom to top, a pixel electrode, an electron transport layer, a light-receiving layer, a hole transport layer, and a common electrode. In this case, the hole injection layer of the light-emitting element 61 can be a common layer, and the common layer can be provided between the hole transport layer and the common electrode of the light-receiving element 62. Also, in the light-emitting element 61, the electron injection layer can be separated for each element.

[0245] By using an MML structure for the light-emitting element 61 and the light-receiving element 62, the light-emitting element 61 and the light-receiving element 62 can have different configurations. For example, the light-emitting element 61 may be configured to include, from bottom to top, a pixel electrode 84, a hole injection layer 85, a hole transport layer 86, a light-emitting layer 87, an electron transport layer 88, a common layer 89 (electron injection layer), and a common electrode 81, while the light-receiving element 62 may be configured to include, from bottom to top, a pixel electrode 84PD, an electron transport layer 88PD, a light-receiving layer 90, a hole transport layer 86PD, a common layer 89, and a common electrode 81. This configuration allows the light-emitting element 61 and the light-receiving element 62 to have the same driving voltage. In this configuration, the light-receiving element 62 may have a hole injection layer between the hole transport layer 86PD and the common layer 89.

[0246] In the following description, it is assumed that the electron transport layer is provided above the hole transport layer. However, the following description can also be applied to the case where the electron transport layer is provided below the hole transport layer, for example, by replacing "electrons" with "holes" and "holes" with "electrons."

[0247] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a material with high hole injection properties, such as an aromatic amine compound or a composite material containing a hole transport material and an acceptor material (electron acceptor material).

[0248] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light emitting layer. The hole transport layer is a layer that contains a hole transport material. The hole transport material is a material having a concentration of 1×10 −６ cm ２ A substance having a hole mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, for example, a material having a high hole transporting property, such as a π-electron-rich heteroaromatic compound (for example, a carbazole derivative, a thiophene derivative, or a furan derivative), or an aromatic amine (a compound having an aromatic amine skeleton), is preferred.

[0249] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light emitting layer. The electron transport layer is a layer that contains an electron transporting material. The electron transporting material is a material having a molecular weight of 1×10 −６ cm ２ A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher electron transporting property than holes. Examples of the electron-transporting material include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, and metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0250] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a material with high electron injection properties. Examples of the material with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the material with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0251] The electron injection layer may be formed of, for example, lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ２ ), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), lithium oxide (LiO ｘ ), or cesium carbonate, or alkali metals, alkaline earth metals, or compounds thereof can be used.

[0252] Alternatively, the electron injection layer may be formed using a material having electron transport properties. For example, a compound having an unshared electron pair and an electron-deficient heteroaromatic ring may be used as the material having electron transport properties. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, or pyridazine ring), and a triazine ring may be used.

[0253] The organic compound having an unshared electron pair preferably has a lowest unoccupied molecular orbital (LUMO) level of −3.6 eV to −2.3 eV. Generally, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by, for example, cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, or inverse photoelectron spectroscopy.

[0254] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), diquinoxalino[2,3-a:2′,3′-c]phenazine (abbreviation: HATNA), or 2,4,6-tris[3′-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz) can be used as the organic compound having an unshared electron pair. Note that NBPhen has a higher glass transition point (Tg) and is superior in heat resistance compared to BPhen.

[0255] The light-emitting layer is a layer containing a light-emitting substance. The light-emitting layer can have one or more light-emitting substances. As the light-emitting substance, for example, a substance that emits light of a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. Furthermore, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0256] Examples of the light-emitting material include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0257] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0258] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton; organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand; platinum complexes; and rare earth metal complexes.

[0259] The light-emitting layer may contain one or more organic compounds (e.g., a host material, an assist material, etc.) in addition to a light-emitting substance (guest material). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material can be used. Furthermore, as the one or more organic compounds, a bipolar material or a TADF material can be used.

[0260] The light-emitting layer preferably contains, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material, which are a combination that easily forms an exciplex. This configuration allows for efficient emission using Exciplex-Triple Energy Transfer (ExTET), which is energy transfer from the exciplex to the light-emitting material (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, the energy transfer becomes smooth and light emission can be achieved efficiently. This configuration allows for high efficiency, low-voltage operation, and a long lifetime of the light-emitting element to be achieved simultaneously.

[0261] As a combination of materials that form an exciplex, it is preferable that the HOMO level (highest occupied molecular orbital level) of the hole transporting material is equal to or higher than the HOMO level of the electron transporting material. It is also preferable that the LUMO level (lowest unoccupied molecular orbital level) of the hole transporting material is equal to or higher than the LUMO level of the electron transporting material. The LUMO level and HOMO level of the material can be derived from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV).

[0262] The formation of exciplexes can be confirmed, for example, by comparing the emission spectra of the hole-transporting material, the electron-transporting material, and a mixed film obtained by mixing these materials and observing the phenomenon that the emission spectrum of the mixed film is shifted to longer wavelengths than the emission spectra of each material (or has a new peak at longer wavelengths). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of the hole-transporting material, the transient PL of the electron-transporting material, and a mixed film obtained by mixing these materials and observing differences in transient response, such as the transient PL lifetime of the mixed film having a longer-lifetime component or a larger proportion of delayed components than the transient PL lifetimes of the individual materials. The above-mentioned transient PL may also be interpreted as transient electroluminescence (EL). That is, the formation of exciplexes can also be confirmed by comparing the transient EL of the hole-transporting material, the transient EL of the electron-transporting material, and a mixed film obtained by mixing these materials and observing differences in transient response.

[0263] The light-emitting layer 87R of the light-emitting element 61R contains a light-emitting organic compound that emits light having an intensity in at least the red wavelength range. The light-emitting layer 87G of the light-emitting element 61G contains a light-emitting organic compound that emits light having an intensity in at least the green wavelength range. The light-emitting layer 87B of the light-emitting element 61B contains a light-emitting organic compound that emits light having an intensity in at least the blue wavelength range. The light-emitting layer 87IR of the light-emitting element 61IR contains a light-emitting organic compound that emits light having an intensity in at least the infrared wavelength range. The light-receiving layer 90 of the light-receiving element 62 contains, for example, an organic compound that has detection sensitivity in the infrared wavelength range.

[0264] A conductive film that is translucent to visible light is used for either the pixel electrode 84 or the common electrode 81, and a conductive film that is reflective is used for the other. By making the pixel electrode 84 translucent and the common electrode 81 reflective, the display device 70 can be a bottom-emission type display device. On the other hand, by making the pixel electrode 84 reflective and the common electrode 81 translucent, the display device 70 can be a top-emission type display device. Note that by making both the pixel electrode 84 and the common electrode 81 translucent, the display device 70 can also be a dual-emission type display device.

[0265] Furthermore, the light-emitting element 61 preferably has a micro-optical resonator (microcavity) structure, which allows the light emitted from the light-emitting layer 87 to resonate between the pixel electrode 84 and the common electrode 81, thereby intensifying the light emitted from the light-emitting element 61.

[0266] When the light-emitting element 61 has a microcavity structure, it is preferable that one of the common electrode 81 or the pixel electrode 84 is an electrode that has both translucency and reflectivity (semi-transmissive / semi-reflective electrode), and the other of the common electrode 81 or the pixel electrode 84 is an electrode that has reflectivity (reflective electrode).

[0267] Alternatively, the light-emitting element 61 may have a microcavity structure by making the light-emitting layer 87IR of the light-emitting element 61IR that emits light with the longest wavelength the thickest, the light-emitting layer 87R of the light-emitting element 61R that emits light with the next longest wavelength the next thickest, the light-emitting layer 87G of the light-emitting element 61G that emits light with the next longest wavelength the next thickest, and the light-emitting layer 87B of the light-emitting element 61B that emits light with the shortest wavelength the thinnest. Note that this is not limiting, and the thickness of each light-emitting layer may be adjusted taking into consideration, for example, the wavelength of light emitted by each light-emitting element, the optical characteristics of the layers that make up the light-emitting element, and the electrical characteristics of the light-emitting element.

[0268] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode for the light emitting element 61 that has a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more. The visible light reflectance of the semi-transparent / semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes is 1×10 −２ When a light-emitting element that emits near-infrared light is used in the display device, the transmittance and reflectance of these electrodes for near-infrared light (light with a wavelength of 750 nm or more and 1300 nm or less) are preferably in the above-mentioned ranges.

[0269] An insulating layer 92 is provided to cover the end portions of the pixel electrodes 84R, 84G, 84B, 84IR, and 84PD. The end portions of the insulating layer 92 are preferably tapered. Note that the insulating layer 92 need not be provided if it is not necessary.

[0270] For example, hole injection layer 85R, hole injection layer 85G, hole injection layer 85B, hole injection layer 85IR, and hole transport layer 86PD each have a region in contact with the upper surface of pixel electrode 84 and a region in contact with the surface of insulating layer 92. Furthermore, an end of hole injection layer 85R, an end of hole injection layer 85G, an end of hole injection layer 85B, an end of hole injection layer 85IR, and an end of hole transport layer 86PD are located on insulating layer 92.

[0271] 20A , a gap is provided between, for example, two light-emitting layers 87 between light-emitting elements 61 that emit light of different colors. In this manner, it is preferable that, for example, light-emitting layer 87R, light-emitting layer 87G, and light-emitting layer 87B are arranged so that they do not contact each other. This makes it possible to preferably prevent current from flowing through two adjacent light-emitting layers 87, thereby preventing unintended light emission. This can increase the contrast of the display device 70, thereby improving the display quality of the display device 70.

[0272] A protective layer 91 is provided on the common electrode 81. The protective layer 91 has a function of preventing impurities such as water from diffusing from above to each light-emitting element.

[0273] The protective layer 91 may have, for example, a single-layer structure or a multilayer structure including at least an inorganic insulating film. Examples of the inorganic insulating film 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, or a hafnium oxide film. Alternatively, the protective layer 91 may be made of a semiconductor material such as indium gallium oxide or indium gallium zinc oxide.

[0274] In this specification and the like, a silicon oxynitride film refers to a film whose composition contains more oxygen than nitrogen, and a silicon nitride oxide film refers to a film whose composition contains more nitrogen than oxygen.

[0275] Alternatively, a laminated film of an inorganic insulating film and an organic insulating film may be used as the protective layer 91. For example, a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films is preferable. Furthermore, it is preferable that the organic insulating film functions as a planarizing film. This allows the upper surface of the organic insulating film to be flat, thereby improving the coverage of the inorganic insulating film thereon and enhancing the barrier properties. Furthermore, since the upper surface of the protective layer 91 is flat, when a structure (e.g., a color filter, a touch sensor electrode, a lens array, etc.) is provided above the protective layer 91, the influence of uneven shapes caused by the structure below can be reduced, which is preferable.

[0276] 20C shows an example of a cross-sectional configuration of the display device 70 in the Y direction, specifically showing an example of a cross-sectional configuration of the light-emitting element 61R and the light-receiving element 62. Note that the light-emitting elements 61G, 61B, and 61IR can also be arranged in the Y direction in the same manner as the light-emitting element 61R.

[0277] 20D shows a connection portion 93 where the connection electrode 82 and the common electrode 81 are electrically connected. In the connection portion 93, the common electrode 81 is provided in contact with the connection electrode 82, and a protective layer 91 is provided to cover the common electrode 81. In addition, an insulating layer 92 is provided to cover the end of the connection electrode 82.

[0278] 20A to 20C show a structure in which the insulating layer 92 is provided to cover the end portions of the pixel electrodes 84R, 84G, 84B, and 84PD, but one embodiment of the present invention is not limited to this. As shown in FIG. 20E, the insulating layer 92 does not have to be provided.

[0279] Furthermore, an insulating layer may be provided in the region between adjacent light-emitting elements 61 and in the region between adjacent light-emitting elements 61 and light-receiving elements 62. Fig. 20E is a cross-sectional view corresponding to the dashed dotted line A1-A2 in Fig. 18B. In Fig. 20E, insulating layers 94 and 96 are provided in the regions.

[0280] The side surfaces of pixel electrode 84R, pixel electrode 84G, pixel electrode 84B, hole injection layer 85R, hole injection layer 85G, hole injection layer 85B, hole transport layer 86R, hole transport layer 86G, hole transport layer 86B, light-emitting layer 87R, light-emitting layer 87G, light-emitting layer 87B, electron transport layer 88R, electron transport layer 88G, and electron transport layer 88B are covered with insulating layer 94 and insulating layer 96, respectively. A common layer 89 is provided on electron transport layer 88R, electron transport layer 88G, electron transport layer 88B, insulating layer 94, and insulating layer 96, and a common electrode 81 is provided on the common layer 89.

[0281] By adopting the above configuration, it is possible to prevent the common layer 89 (or the common electrode 81) from coming into contact with any of the sides of the pixel electrode 84R, the pixel electrode 84G, the pixel electrode 84B, the light-emitting layer 87R, the light-emitting layer 87G, and the light-emitting layer 87B, thereby preventing short circuits (electrical short circuits) of the light-emitting elements.

[0282] The insulating layer 94 preferably covers at least the side surfaces of the pixel electrodes 84R, 84G, and 84B. Furthermore, the insulating layer 94 preferably covers the side surfaces of the hole injection layer 85R, 85G, 85B, hole transport layer 86R, hole transport layer 86G, hole transport layer 86B, light-emitting layer 87R, light-emitting layer 87G, light-emitting layer 87B, electron transport layer 88R, electron transport layer 88G, and electron transport layer 88B. The insulating layer 94 can be configured to be in contact with each side surface of the pixel electrode 84R, pixel electrode 84G, pixel electrode 84B, hole injection layer 85R, hole injection layer 85G, hole injection layer 85B, hole transport layer 86R, hole transport layer 86G, hole transport layer 86B, light-emitting layer 87R, light-emitting layer 87G, light-emitting layer 87B, electron transport layer 88R, electron transport layer 88G, and electron transport layer 88B.

[0283] The insulating layer 96 is provided on the insulating layer 94 so as to fill recesses formed in the insulating layer 94. The insulating layer 96 can be configured to overlap with each side surface of the pixel electrode 84R, the pixel electrode 84G, the pixel electrode 84B, the hole injection layer 85R, the hole injection layer 85G, the hole injection layer 85B, the hole transport layer 86R, the hole transport layer 86G, the hole transport layer 86B, the light-emitting layer 87R, the light-emitting layer 87G, the light-emitting layer 87B, the electron transport layer 88R, the electron transport layer 88G, and the electron transport layer 88B, with the insulating layer 94 interposed therebetween.

[0284] Note that either insulating layer 94 or insulating layer 96 may not be provided. If insulating layer 94 is not provided, insulating layer 96 may be configured to contact the side surfaces of each of light-emitting layers 87R, 87G, and 87B. The display device may also have an insulating layer that covers the ends of the pixel electrodes. In this case, one or both of insulating layer 94 and insulating layer 96 may be provided on the insulating layer.

[0285] The common layer 89 and the common electrode 81 are provided over the electron transport layer 88R, the electron transport layer 88G, the electron transport layer 88B, the insulating layer 94, and the insulating layer 96. Before the insulating layer 94 and the insulating layer 96 are provided, a step is generated between a region where the pixel electrode and the light-emitting layer are provided and a region where the pixel electrode and the light-emitting layer are not provided (a region between light-emitting elements). By including the insulating layer 94 and the insulating layer 96, the display device of one embodiment of the present invention can flatten the step and improve the coverage of the common layer 89 and the common electrode 81. Therefore, poor connection due to disconnection can be suppressed. Alternatively, the step can be suppressed from locally thinning the common electrode 81, resulting in an increase in electrical resistance.

[0286] In order to improve the flatness of the surfaces on which the common layer 89 and the common electrode 81 are formed, it is preferable that the heights of the upper surfaces of the insulating layers 94 and 96 are the same or approximately the same as the height of the upper surface of at least one of the electron transport layers 88R, 88G, and 88B. The upper surface of the insulating layer 96 preferably has a flat shape, but may have protrusions or recesses.

[0287] The insulating layer 94 has an area in contact with the side surfaces of the light-emitting layers 87R, 87G, and 87B, and functions as a protective insulating layer for the light-emitting layers 87R, 87G, and 87B. Providing the insulating layer 94 can prevent impurities (e.g., oxygen or moisture) from entering the interior from the side surfaces of the light-emitting layers 87R, 87G, and 87B, thereby providing a highly reliable display device.

[0288] If the width (thickness) of the insulating layer 94 is large in a region in contact with the side surfaces of the light-emitting layers 87R, 87G, and 87B in a cross-sectional view, the spacing between the light-emitting layers 87R, 87G, and 87B will increase, which may result in a low aperture ratio. Also, if the width (thickness) of the insulating layer 94 is small in a region in contact with the side surfaces of the light-emitting layers 87R, 87G, and 87B in a cross-sectional view, the effect of suppressing impurities from penetrating into the interior from the side surfaces of the light-emitting layers 87R, 87G, and 87B may be reduced. In a cross-sectional view, the width (thickness) of insulating layer 94 in regions contacting the side surfaces of light-emitting layer 87R, light-emitting layer 87G, and light-emitting layer 87B is preferably 3 nm to 200 nm, more preferably 3 nm to 150 nm, even more preferably 5 nm to 150 nm, even more preferably 5 nm to 100 nm, even more preferably 10 nm to 100 nm, and even more preferably 10 nm to 50 nm. By setting the width (thickness) of insulating layer 94 within the above range, a display device having a high aperture ratio and high reliability can be obtained.

[0289] The insulating layer 94 may be an insulating layer containing an inorganic material. For example, inorganic insulating films such as an insulating oxide film, an insulating nitride film, an insulating oxynitride film, and an insulating nitride oxide film may be used for the insulating layer 94. The insulating layer 94 may have a single-layer structure or a multilayer structure. Examples of insulating oxide films include silicon oxide films, aluminum oxide films, magnesium oxide films, indium gallium zinc oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of insulating nitride films include silicon nitride films and aluminum nitride films. Examples of insulating oxynitride films include silicon oxynitride films and aluminum oxynitride films. Examples of insulating nitride films include silicon nitride oxide films and aluminum nitride oxide films. Aluminum oxide is particularly preferred because it has a high etching selectivity with respect to the light-emitting layer and protects the light-emitting layer during the formation of the insulating layer 96, which will be described later. In particular, by applying an inorganic insulating film such as an aluminum oxide film, a hafnium oxide film, or a silicon oxide film formed by the ALD method to the insulating layer 94, it is possible to form an insulating layer 94 with few pinholes and excellent function of protecting the light-emitting layer.

[0290] In this specification and the like, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0291] The insulating layer 94 can be formed by a sputtering method, a CVD method, a PLD method, an ALD method, or the like. The insulating layer 94 is preferably formed by an ALD method, which has good coverage.

[0292] The insulating layer 96 provided on the insulating layer 94 functions to flatten recesses formed in the insulating layer 94 between adjacent light-emitting devices. In other words, the insulating layer 96 improves the flatness of the surface on which the common electrode 81 is formed. An insulating layer containing an organic material can be suitably used as the insulating layer 96. Examples of suitable materials for the insulating layer 96 include acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene-based resin, phenolic resin, and precursors of these resins. Examples of suitable organic materials for the insulating layer 96 include polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, and alcohol-soluble polyamide resin. A photosensitive resin (also referred to as an organic resin) can be used as the insulating layer 96. Photoresist may be used as the photosensitive resin. The photosensitive resin may be a positive-tone material or a negative-tone material.

[0293] The difference in height between the upper surface of insulating layer 96 and the upper surface of any one of light-emitting layers 87R, 87G, and 87B is, for example, preferably 0.5 times or less, and more preferably 0.3 times or less, the thickness of insulating layer 96. Alternatively, for example, insulating layer 96 may be provided so that the upper surface of any one of light-emitting layers 87R, 87G, and 87B is higher than the upper surface of insulating layer 96. Alternatively, for example, insulating layer 96 may be provided so that the upper surface of any one of light-emitting layers 87R, 87G, and 87B is higher than the upper surface of insulating layer 96.

[0294] In the display device 70, the pixel 80 is configured with a subpixel having a light-emitting element 61R, a subpixel having a light-emitting element 61G, a subpixel having a light-emitting element 61B, a subpixel having a light-emitting element 61IR, and a subpixel having a light-receiving element 62, but one embodiment of the present invention is not limited to this. For example, display devices different from the display device 70 shown in FIG. 18A and the like are shown in FIGS. 21A, 21B, 22A, 22B, 23A, and 23B.

[0295] The display device 70 shown in Fig. 21A differs from the display device 70 shown in Fig. 18A in that the pixel 80 is composed of a sub-pixel having a light-emitting element 61R, a sub-pixel having a light-emitting element 61G, a sub-pixel having a light-emitting element 61B, and a sub-pixel having a light-receiving element 62. In this case, the light-emitting element 61IR may be provided between the display region 95 and the connection electrode 82. Alternatively, as shown in Fig. 21B, the light-emitting element 61IR may be provided on the periphery of the display region 95 and the connection electrode 82. In this way, the area occupied by the light-receiving element 62 in the display device 70 can be made larger, and the light detection sensitivity of the light-receiving element 62 can be improved.

[0296] 21A , the light-emitting elements 61IR can be provided along the periphery of the display area 95. For example, the light-emitting elements 61IR may be provided along one side of the periphery of the display area 95, or may be provided across two or more sides of the periphery of the display area 95. That is, when the top surface of the display area 95 has a rectangular shape, the arrangement of the light-emitting elements 61IR in top view can be, for example, a strip shape, an L-shape, a U-shape (square bracket shape), a square shape, or the like.

[0297] 21B , the light-emitting elements 61IR can be provided along the outer periphery of the connection electrode 82. For example, the light-emitting elements 61IR may be provided along one side of the outer periphery of the connection electrode 82, or may be provided over two or more sides of the outer periphery of the connection electrode 82. In other words, when the top surface shape of the connection electrode 82 is rectangular, the arrangement of the light-emitting elements 61IR in top view can be, for example, strip-shaped, L-shaped, U-shaped (square bracket-shaped), quadrangular, or the like.

[0298] 21A and 21B illustrate an example in which the Y-direction width of the light-emitting element 61IR is approximately the same as the Y-direction width of the pixel 80, but one embodiment of the present invention is not limited to this. The Y-direction width of the light-emitting element 61IR may be larger or smaller than the Y-direction width of the pixel 80. Also, FIGS. 21A and 21B illustrate an example in which the number of light-emitting elements 61IR in the Y direction is the same as the number of pixels 80, but one embodiment of the present invention is not limited to this. The number of light-emitting elements 61IR in the Y direction may be different from the number of pixels 80, and may be one or more. Also, FIGS. 21A and 21B illustrate an example in which one light-emitting element 61IR is provided in the X direction, but one embodiment of the present invention is not limited to this. The number of light-emitting elements 61IR in the X direction may be more than one.

[0299] The display device 70 shown in Fig. 22A differs from the display device 70 shown in Fig. 18A in that the pixel 80 is composed of a sub-pixel having a light-emitting element 61R, a sub-pixel having a light-emitting element 61G, a sub-pixel having a light-emitting element 61B, and a sub-pixel having a light-emitting element 61IR. In this case, the light-receiving element 62 may be provided between the display region 95 and the connection electrode 82. Alternatively, as shown in Fig. 22B, the light-receiving element 62 may be provided on the periphery of the display region 95 and the connection electrode 82. In this way, the area occupied by the light-receiving element 62 in the display device 70 can be made larger, and the light detection sensitivity of the light-receiving element 62 can be improved.

[0300] 22A , the light receiving elements 62 can be provided along the periphery of the display area 95. For example, the light receiving elements 62 can be provided along one side of the periphery of the display area 95, or can be provided across two or more sides of the periphery of the display area 95. That is, when the top surface of the display area 95 has a rectangular shape, the arrangement of the light receiving elements 62 in the top view can be, for example, a strip shape, an L-shape, a U-shape (square bracket shape), a square shape, or the like.

[0301] 22B , the light receiving elements 62 can be provided along the outer periphery of the connection electrode 82. For example, the light receiving elements 62 may be provided along one side of the outer periphery of the connection electrode 82, or may be provided over two or more sides of the outer periphery of the connection electrode 82. In other words, when the top surface shape of the connection electrode 82 is rectangular, the arrangement of the light receiving elements 62 in top view can be, for example, strip-shaped, L-shaped, U-shaped (square bracket-shaped), quadrangular, or the like.

[0302] 22A and 22B illustrate an example in which the width of the light receiving element 62 in the Y direction is approximately the same as the width of the pixel 80 in the Y direction, but this embodiment of the present invention is not limited to this. The width of the light receiving element 62 in the Y direction may be larger or smaller than the width of the pixel 80 in the Y direction. Also, FIGS. 22A and 22B illustrate an example in which the number of light receiving elements 62 in the Y direction is the same as the number of pixels 80, but this embodiment of the present invention is not limited to this. The number of light receiving elements 62 in the Y direction may be different from the number of pixels 80, and may be one or more. Also, FIGS. 22A and 22B illustrate an example in which one light receiving element 62 is provided in the X direction, but this embodiment of the present invention is not limited to this. The number of light receiving elements 62 in the X direction may be more than one.

[0303] The display device 70 shown in Fig. 23A differs from the display device 70 shown in Fig. 18A in that the pixel 80 is composed of a sub-pixel having a light-emitting element 61R, a sub-pixel having a light-emitting element 61G, and a sub-pixel having a light-emitting element 61B. In this case, the light-emitting element 61IR and the light-receiving element 62 may be provided between the display region 95 and the connection electrode 82. Alternatively, as shown in Fig. 23B, the light-emitting element 61IR and the light-receiving element 62 may be provided on the periphery of the display region 95 and the connection electrode 82. This allows the lengths of the light-emitting elements 61R, 61G, and 61B in the Y direction to be increased, thereby increasing the brightness of the light emitted by the pixel 80.

[0304] In the display device 70 shown in FIG. 23A , the light-emitting elements 61IR and the light-receiving elements 62 can be arranged along the periphery of the display area 95. For example, they may be arranged along one side of the periphery of the display area 95, or they may be arranged along two or more sides of the periphery of the display area 95. That is, when the top surface of the display area 95 is rectangular, the arrangement of the light-emitting elements 61IR and the light-receiving elements 62 in the top view can be, for example, strip-shaped, L-shaped, U-shaped (square bracket-shaped), or quadrangular. Furthermore, the arrangement of the light-emitting elements 61IR and the light-receiving elements 62 may be different. For example, the light-emitting elements 61IR in the top view may be arranged on two opposing sides of the display area 95, and the light-receiving elements 62 in the top view may be arranged on two other sides.

[0305] In the display device 70 shown in FIG. 23B , the light-emitting elements 61IR and the light-receiving elements 62 can be arranged along the outer periphery of the connection electrode 82. For example, they may be arranged along one side of the outer periphery of the connection electrode 82, or they may be arranged along two or more sides of the outer periphery of the connection electrode 82. That is, when the top surface shape of the connection electrode 82 is rectangular, the arrangement of the light-emitting elements 61IR and the light-receiving elements 62 in the top view can be, for example, strip-shaped, L-shaped, U-shaped (square bracket-shaped), or rectangular. Furthermore, the arrangement of the light-emitting elements 61IR and the light-receiving elements 62 may be different. For example, the light-emitting elements 61IR in the top view may be arranged on two opposing sides of the connection electrode 82, and the light-receiving elements 62 in the top view may be arranged on two other sides.

[0306] 23A and 23B illustrate an example in which the sum of the Y-direction width of the light-emitting element 61IR and the Y-direction width of the light-receiving element 62 is approximately the same as the Y-direction width of the pixel 80, but this aspect of the present invention is not limited to this. The Y-direction widths of the light-emitting element 61IR and the light-receiving element 62 may be greater or smaller than the Y-direction width of the pixel 80. Also, while FIGS. 23A and 23B illustrate an example in which the number of light-emitting elements 61IR, the number of light-receiving elements 62, and the number of pixels 80 in the Y direction are the same, this aspect of the present invention is not limited to this. The number of light-emitting elements 61IR and the number of light-receiving elements 62 in the Y direction may be different from the number of pixels 80, and may be one or more. Also, the number of light-emitting elements 61IR and the number of light-receiving elements 62 in the Y direction may be different. 23A and 23B show an example in which one light-emitting element 61IR and one light-receiving element 62 are provided in the X direction, but one embodiment of the present invention is not limited thereto. The number of each of the light-emitting element 61IR and the light-receiving element 62 in the X direction may be plural.

[0307] 24A , the light-emitting element has an EL layer 686 between a pair of electrodes (electrode 672 and electrode 688). The EL layer 686 can be formed of a plurality of layers, such as a layer 4420, a light-emitting layer 4411, and a layer 4430. The layer 4420 can have, 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 contains, for example, a light-emitting compound. The layer 4430 can have, 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).

[0308] A structure having 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. 24A is referred to as a single structure in this specification and the like.

[0309] 24B shows a modified example of an EL layer 686 included in the light-emitting element shown in Fig. 24A. Specifically, the light-emitting element shown in Fig. 24B includes a layer 4430-1 on an electrode 672, 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 an electrode 688 on the layer 4420-2. For example, when the electrode 672 is an anode and the electrode 688 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 electrode 672 is a cathode and the electrode 688 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. Such a layer structure enables carriers to be efficiently injected into the light-emitting layer 4411, and the efficiency of carrier recombination in the light-emitting layer 4411 to be increased.

[0310] Note that a structure in which a plurality of light-emitting layers (light-emitting layer 4411, light-emitting layer 4412, and light-emitting layer 4413) are provided between the layer 4420 and the layer 4430 as shown in FIG. 24C is also a variation of the single structure.

[0311] 24D , a configuration in which a plurality of light-emitting units (EL layer 686 a and EL layer 686 b) are connected in series via an intermediate layer (charge generating layer) 4440 is referred to as a tandem structure in this specification. Note that although the configuration shown in FIG. 24D is referred to as a tandem structure in this specification, the present invention is not limited to this, and for example, the tandem structure may also be referred to as a stack structure. Note that the tandem structure makes it possible to obtain a light-emitting element that can emit light with high brightness.

[0312] 24C and 24D, the layer 4420 and the layer 4430 may have a laminated structure consisting of two or more layers, as shown in FIG. 24B.

[0313] Furthermore, a structure in which each light-emitting element produces a different emission color (here, blue (B), green (G), and red (R)) is sometimes called an SBS (Side By Side) structure.

[0314] Furthermore, when comparing the above-mentioned single and tandem structures with the SBS structure, the order of decreasing power consumption is SBS, tandem, and single. The SBS structure is preferable for reducing power consumption. Meanwhile, the single and tandem structures are preferable because their manufacturing processes are simpler than those of the SBS structure, allowing for lower manufacturing costs and higher manufacturing yields.

[0315] The light-emitting color of the light-emitting element can be, for example, red, green, blue, cyan, magenta, yellow, or white, depending on the material constituting the EL layer 686. Furthermore, the color purity can be further improved by providing the light-emitting element with a microcavity structure.

[0316] A light-emitting element that emits white light preferably has a configuration in which two or more types of light-emitting materials are included in the light-emitting layer. When white light emission is obtained using two types of light-emitting materials, light-emitting materials may be selected such that the colors of light emitted by the two types of light-emitting materials are in a complementary color relationship. For example, by making the color of light emitted by the first light-emitting material and the color of light emitted by the second light-emitting material be in a complementary color relationship, a light-emitting element that emits white light as a whole can be obtained. Furthermore, when white light emission is obtained using three or more types of light-emitting materials, the colors of light emitted by the three or more light-emitting materials may be combined to form a light-emitting element that can emit white light as a whole.

[0317] The light-emitting layer preferably contains two or more light-emitting materials that emit light of, for example, R (red), G (green), B (blue), Y (yellow), or O (orange). Alternatively, the light-emitting layer preferably contains two or more light-emitting materials, and the light emitted by each of the light-emitting materials preferably contains spectral components of two or more colors of R, G, and B.

[0318] <Configuration Example of Light-Emitting Element and Light-Receiving Element> A display device according to one embodiment of the present invention is a top-emission type that emits light in a direction opposite to a substrate on which a light-emitting element is formed. In this embodiment, a display device including a top-emission light-emitting element and a light-receiving element will be described as an example.

[0319] In this specification and the like, unless otherwise specified, even when describing a configuration having a plurality of elements (e.g., light-emitting elements or light-emitting layers), when describing matters common to each element, the alphabet will be omitted. For example, when describing matters common to light-emitting layer 383R and light-emitting layer 383G, the light-emitting layer may be referred to as light-emitting layer 383.

[0320] The display device 380A shown in Figure 25 has a light receiving element 370PD, a light emitting element 370R that emits red (R) light, a light emitting element 370G that emits green (G) light, a light emitting element 370B that emits blue (B) light, and a light emitting element 370IR that emits infrared light (IR).

[0321] Each light-emitting element has a pixel electrode 371, a hole injection layer 381, a hole transport layer 382, ​​a light-emitting layer, an electron transport layer 384, an electron injection layer 385, and a common electrode 375 stacked in this order. Light-emitting element 370R has a light-emitting layer 383R, light-emitting element 370G has a light-emitting layer 383G, light-emitting element 370B has a light-emitting layer 383B, and light-emitting element 370IR has a light-emitting layer 383IR. Light-emitting layer 383R contains a light-emitting material that emits red light, light-emitting layer 383G contains a light-emitting material that emits green light, light-emitting layer 383B contains a light-emitting material that emits blue light, and light-emitting layer 383IR contains a light-emitting material that emits infrared light.

[0322] The light emitting element is an electroluminescent element that emits light toward the common electrode 375 when a voltage is applied between the pixel electrode 371 and the common electrode 375 .

[0323] The light receiving element 370PD has a pixel electrode 371, a hole injection layer 381, a hole transport layer 382, ​​an active layer 373, an electron transport layer 384, an electron injection layer 385, and a common electrode 375 stacked in this order.

[0324] The light receiving element 370PD is a photoelectric conversion element that receives light incident from outside the display device 380A and converts it into an electrical signal.

[0325] In this embodiment, in both the light-emitting element and the light-receiving element, the pixel electrode 371 functions as an anode and the common electrode 375 functions as a cathode. In other words, the light-receiving element is driven by applying a reverse bias between the pixel electrode 371 and the common electrode 375, so that the light incident on the light-receiving element can be detected, an electric charge can be generated, and the electric charge can be extracted as a current.

[0326] In the display device of this embodiment, an organic compound is used for the active layer 373 of the light-receiving element 370PD. The layers of the light-receiving element 370PD other than the active layer 373 can be configured in common with the light-emitting element. Therefore, by simply adding a step of forming the active layer 373 to the manufacturing process of the light-emitting element, the light-receiving element 370PD can be formed in parallel with the formation of the light-emitting element. Furthermore, the light-emitting element and the light-receiving element 370PD can be formed on the same substrate. Therefore, the light-receiving element 370PD can be built into the display device without significantly increasing the number of manufacturing steps.

[0327] The display device 380A shows an example in which the light receiving element 370PD and the light emitting element have a common configuration, except that the active layer 373 of the light receiving element 370PD and the light emitting layer 383 of the light emitting element are fabricated separately. However, the configuration of the light receiving element 370PD and the light emitting element is not limited to this. The light receiving element 370PD and the light emitting element may have layers fabricated separately from each other in addition to the active layer 373 and the light emitting layer 383. It is preferable that the light receiving element 370PD and the light emitting element have one or more layers used in common (common layers). This allows the light receiving element 370PD to be incorporated into the display device without significantly increasing the number of fabrication steps.

[0328] A conductive film that transmits visible light is used for the electrode from which light is extracted, either the pixel electrode 371 or the common electrode 375. It is preferable to use a conductive film that reflects visible light for the electrode from which light is not extracted.

[0329] The light-emitting element of the display device of this embodiment preferably has a micro-optical resonator (microcavity) structure. Therefore, one of a pair of electrodes of the light-emitting element preferably has an electrode that is transparent and reflective to visible light (semi-transmissive / semi-reflective electrode), and the other preferably has an electrode that is reflective to visible light (reflective electrode). When the light-emitting element has a microcavity structure, light emitted from the light-emitting layer can be resonated between both electrodes, thereby intensifying the light emitted from the light-emitting element.

[0330] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode with a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more for the light emitting element. The visible light reflectance of the semi-transparent / semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes is 1×10 −２ When the light-emitting element emits near-infrared light (light having a wavelength of 750 nm or more and 1300 nm or less), the transmittance or reflectance of these electrodes for near-infrared light preferably satisfies the above-mentioned numerical range, similar to the transmittance or reflectance for visible light.

[0331] The light-emitting element has at least a light-emitting layer 383. The light-emitting element may further have, as a layer other than the light-emitting layer 383, a layer containing, for example, a substance with high hole-injection properties, a substance with high hole-transport properties, a hole-blocking material, a substance with high electron-transport properties, a substance with high electron-injection properties, an electron-blocking material, or a bipolar substance (a substance with high electron-transport properties and high hole-transport properties).

[0332] For example, the light-emitting element and the light-receiving element may have one or more layers of the hole injection layer, hole transport layer, electron transport layer, and electron injection layer in common, or the light-emitting element and the light-receiving element may have one or more layers of the hole injection layer, hole transport layer, electron transport layer, and electron injection layer formed differently from each other.

[0333] In a light-receiving element, the hole transport layer is a layer that transports holes generated in the active layer based on incident light to the anode, and the electron transport layer is a layer that transports electrons generated in the active layer based on incident light to the cathode.

[0334] Note that for the hole injection layer, the hole transport layer, the electron transport layer, the electron injection layer, and the light-emitting layer, the contents described in <Top view and cross-sectional view of the light-emitting element and its periphery> can be referred to.

[0335] The active layer 373 includes a semiconductor. Examples of the semiconductor include an inorganic semiconductor such as silicon and an organic semiconductor including an organic compound. In this embodiment, an example is shown in which an organic semiconductor is used as the semiconductor included in the active layer 373. Using an organic semiconductor is preferable because the light-emitting layer 383 and the active layer 373 can be formed by the same method (for example, vacuum deposition), allowing the use of a common manufacturing device.

[0336] The n-type semiconductor material of the active layer 373 is, for example, fullerene (e.g., C ６０ , C ７０ Examples of suitable organic semiconductor materials include electron-accepting organic semiconductor materials such as fullerene derivatives, or fullerene derivatives. Fullerenes have a soccer ball-like shape, which is energetically stable. Fullerenes have deep (low) HOMO and LUMO levels. Because fullerenes have a deep LUMO level, they have extremely high electron-accepting (acceptor) properties. Normally, when π-electron conjugation (resonance) spreads across a plane, as in benzene, electron-donating (donor) properties increase, but fullerenes have a spherical shape, so they have high electron-accepting properties despite the wide spread π-electron conjugation. High electron-accepting properties allow charge separation to occur quickly and efficiently, making them useful as light-receiving elements. C ６０ , C ７０ Both have a wide absorption band in the visible light region, and C ７０ is C ６０

[0033] Other fullerene derivatives include, for example, [6,6]-Phenyl-C71-butylic acid methyl ester (abbreviation: PC70BM), [6,6]-Phenyl-C61-butylic acid methyl ester (abbreviation: PC60BM), and 1',1",4',4"-Tetrahydro-di[1,4]methanenaphthaleno[1,2:2',3',56,60:2",3"][5,6]fullerene-C60 (abbreviation: ICBA).

[0337] Examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0338] Examples of the p-type semiconductor material of the active layer 373 include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanethene (DBP), zinc phthalocyanine (ZnPc), tin phthalocyanine (SnPc), and quinacridone.

[0339] Examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, and compounds having an aromatic amine skeleton. Examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indolocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives.

[0340] The HOMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the HOMO level of the electron-accepting organic semiconductor material, and the LUMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the LUMO level of the electron-accepting organic semiconductor material.

[0341] It is preferable to use a spherical fullerene as the electron-accepting organic semiconductor material and a planar organic semiconductor material as the electron-donating organic semiconductor material. Molecules with similar shapes tend to aggregate together, and when molecules of the same type aggregate, the energy levels of their molecular orbitals become close, which can improve carrier transport properties.

[0342] For example, the active layer 373 is preferably formed by co-evaporating an n-type semiconductor and a p-type semiconductor, or alternatively, the active layer 373 may be formed by laminating an n-type semiconductor and a p-type semiconductor.

[0343] The light-emitting element and the light-receiving element can be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may further contain an inorganic compound. The layers constituting the light-emitting element and the light-receiving element can be formed by, for example, a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, a coating method, or the like.

[0344] For example, a polymer compound such as poly(3,4-ethylenedioxythiophene) / (polystyrene sulfonic acid) (abbreviated as PEDOT / PSS) can be used as the hole transport material, and an inorganic compound such as molybdenum oxide or copper iodide (CuI) can be used as the electron transport material.

[0345] Furthermore, for example, a polymer compound such as Poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c']dithiophene-1,3-diyl]] polymer (abbreviation: PBDB-T) or a PBDB-T derivative, which functions as a donor, can be used for the active layer 373. For example, a method of dispersing an acceptor material in PBDB-T or a PBDB-T derivative can be used.

[0346] Furthermore, three or more types of materials may be mixed in the active layer 373. For example, in order to expand the wavelength range, a third material may be mixed in addition to an n-type semiconductor material and a p-type semiconductor material. In this case, the third material may be a low-molecular-weight compound or a high-molecular-weight compound.

[0347] 26 is a cross-sectional view showing a configuration example of a display device 70. The display device 70 has a stacked structure of a transistor 310 having a channel formed in a substrate 301 and a transistor 320 having a channel formed in a semiconductor layer containing metal oxide.

[0348] An insulating layer 261 is provided to cover the transistor 310, and a conductive layer 251 is provided over the insulating layer 261. The conductive layer 251 is electrically connected to one of the source and drain of the transistor 310 through a plug 271 embedded in the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided over the insulating layer 262. The conductive layer 251 and the conductive layer 252 each function as a wiring. 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 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0349] The transistor 320 can be used as a transistor that constitutes a pixel circuit or a transistor that constitutes a memory cell. The transistor 310 can be used as a transistor that constitutes a memory cell, a transistor that constitutes a driver circuit for driving the pixel circuit, or a transistor that constitutes an arithmetic circuit. The transistors 310 and 320 can be used as transistors that constitute various circuits, such as an arithmetic circuit or a memory circuit.

[0350] The transistor 310 has 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 one of a source and a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311 and functions as an insulating layer.

[0351] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0352] 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.

[0353] 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 .

[0354] The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 301 side to the transistor 320 and prevents oxygen from being released from the semiconductor layer 321 toward the insulating layer 332. As the insulating layer 332, 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, can be used.

[0355] 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 second gate electrode of the transistor 320, and part of the insulating layer 326 functions as a second 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.

[0356] The conductive layer 327 may be a single layer or a stack of two or more conductive layers. When the conductive layer 327 has a structure in which two conductive layers are stacked, the conductive layer in contact with the bottom and sidewall of the opening in the insulating layer 326 is preferably made of a conductive material that has a function of suppressing the diffusion of impurities such as water or hydrogen, or oxygen. Examples of such conductive materials include titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, and ruthenium oxide. This structure can suppress the diffusion of impurities such as water or hydrogen into the semiconductor layer 321.

[0357] A single layer or a stack of two or more inorganic insulating films may be used as the insulating layer 326. When a stack of two or more inorganic insulating films is used as the insulating layer 326, one of the inorganic insulating films included in the insulating layer 326 preferably functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 301 side to the transistor 320. As the inorganic insulating film, an insulating film similar to the insulating layer 328 can be used.

[0358] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide (also referred to as an oxide semiconductor) film having semiconductor properties. The semiconductor layer 321 preferably includes a metal oxide containing at least one of indium, an element M (the element M is aluminum, gallium, yttrium, or tin), and zinc. An OS transistor using such a metal oxide for a channel formation region has a characteristic of extremely low off-state current. Therefore, an OS transistor is preferably used as a transistor provided in a pixel circuit because analog data written to the pixel circuit can be retained for a long period of time. Similarly, an OS transistor is preferably used as a transistor used in a memory cell because analog data written to the memory cell can be retained for a long period of time.

[0359] 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.

[0360] Furthermore, for example, an insulating layer 328 is provided to cover the top surfaces and side surfaces of the pair of conductive layers 325 and the 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 into 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.

[0361] 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, the insulating layer 323 being in contact with side surfaces of the insulating layer 264, the insulating layer 328, and the conductive layer 325 and the top surface of the semiconductor layer 321. The conductive layer 324 functions as a first gate electrode, and the insulating layer 323 functions as a first gate insulating layer.

[0362] The insulating layer 323 can be, for example, an inorganic insulating film such as a silicon oxide film or a silicon oxynitride film. Note that the insulating layer 323 is not limited to a single-layer inorganic insulating film, and a stack of two or more inorganic insulating films may be used. For example, an aluminum oxide film, a hafnium oxide film, a silicon nitride film, or the like may be provided as a single layer or a stack on the side in contact with the conductive layer 324. This can suppress oxidation of the conductive layer 324. Furthermore, for example, an aluminum oxide film or a hafnium oxide film may be provided on the side in contact with the insulating layer 264, the insulating layer 328, and the conductive layer 325. This can suppress, for example, desorption of oxygen from the semiconductor layer 321, excessive supply of oxygen to the semiconductor layer 321, oxidation of the conductive layer 325, and the like.

[0363] 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.

[0364] Note that the conductive layer 327 and the conductive layer 324 preferably overlap with each other through an insulator on the outer side of the side surface in the channel width direction of the semiconductor layer 321. With this structure, the channel formation region of the semiconductor layer 321 can be electrically surrounded by the electric field of the conductive layer 327 functioning as the second gate electrode and the electric field of the conductive layer 324 functioning as the first gate electrode. In this specification and the like, a transistor structure in which the channel formation region is electrically surrounded by the electric fields of the first gate electrode and the second gate electrode is referred to as a surrounded channel (S-channel) structure.

[0365] In this specification and the like, a transistor with an S-channel structure refers to a transistor structure in which a channel formation region is electrically surrounded by the electric fields of one and the other of a pair of gate electrodes. The S-channel structure disclosed in this specification and the like is different from a fin structure and a planar structure. By adopting the S-channel structure, it is possible to improve resistance to the short channel effect, in other words, to make the transistor less susceptible to the short channel effect.

[0366] By configuring the transistor 320 as a normally-off transistor and having the above-described S-channel structure, the channel formation region can be electrically surrounded. Therefore, the transistor 320 can also be regarded as having a Gate All Around (GAA) structure or a Lateral Gate All Around (LGAA) structure. By configuring the transistor 320 as an S-channel structure, a GAA structure, or an LGAA structure, the channel formation region formed at or near the interface between the semiconductor layer 321 and the gate insulating film can be the entire bulk of the semiconductor layer 321. Therefore, the current density flowing through the transistor can be improved, thereby improving the on-state current of the transistor or the field-effect mobility of the transistor.

[0367] 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 into 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.

[0368] The plug 274 electrically connected to one of the pair of conductive layers 325 is provided so as to be embedded in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328. The plug 274 has a structure in which the conductive layer is provided as a single layer or a stacked structure of two or more layers. When the plug 274 has a structure in which two conductive layers are stacked, it is preferable to use a conductive material that is difficult for hydrogen and oxygen to diffuse into the conductive layer that covers 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 a portion of the top surface of the conductive layer 325. This structure can prevent impurities such as water or hydrogen from the insulating layer 264 or the like from being mixed into the semiconductor layer 321 through the plug 274. Furthermore, it can prevent oxygen contained in the insulating layer 264 from being absorbed by the plug 274.

[0369] Furthermore, an insulating layer 275 is provided in contact with the side surface of the plug 274. That is, a configuration may be adopted in which the insulating layer 275 is provided in contact with the insulating layer 265, the insulating layer 329, and the inner wall of the opening of the insulating layer 264, and the plug 274 is provided in contact with the side surface of the insulating layer 275 and part of the upper surface of the conductive layer 325. Note that there may be cases in which the insulating layer 275 does not need to be provided.

[0370] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 245 functions as one electrode of the capacitor 240, the conductive layer 241 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0371] The conductive layer 245 is provided over the insulating layer 265 and is buried in the insulating layer 254. The conductive layer 245 is electrically connected to one of the source and drain of the transistor 320 by a plug 274 buried in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328. The insulating layer 243 is provided to cover the conductive layer 245. The conductive layer 241 is provided in a region overlapping with the conductive layer 245 with the insulating layer 243 interposed therebetween.

[0372] An insulating layer 255 is provided to cover the capacitor 240, and for example, a light-emitting element 61, a light-receiving element 62, etc. are provided on the insulating layer 255. A protective layer 91 is provided on the light-emitting element 61 and the light-receiving element 62, and a substrate 420 is bonded to the upper surface of the protective layer 91 by a resin layer 419. A light-transmitting substrate can be used as the substrate 420.

[0373] The pixel electrode 84 of the light-emitting element 61 and the pixel electrode 84PD of the light-receiving element 62 are electrically connected to either the source or drain of the transistor 320 by a plug 256 embedded in the insulating layer 255 and the insulating layer 243, a conductive layer 245 embedded in the insulating layer 254, and a plug 274 embedded in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328.

[0374] With this configuration, OS transistors that constitute pixel circuits and memory cells can be arranged directly below the light-receiving elements and light-emitting elements, and driver circuits and arithmetic circuits, for example, can also be arranged, making it possible to miniaturize a display device with high performance.

[0375] 26 illustrates a configuration in which the transistor 310 and the transistor 320 are stacked in the display device 70. Note that the configuration of the display device 70 is not limited to this, and the display device 70 may have a configuration including the transistor 310 but not the transistor 320, a configuration including the transistor 320 but not the transistor 310, a configuration in which multiple transistors 320 are stacked, or a configuration in which the transistor 310 and multiple transistors 320 are stacked over the transistor 310.

[0376] In addition, when a silicon substrate is used as the substrate 301, a photodiode having a photoelectric conversion layer formed thereon may be formed on the silicon substrate, and the photodiode can be used as a light-receiving element included in the display device of one embodiment of the present invention. In other words, the light-receiving element included in the display device of one embodiment of the present invention may be formed on a silicon substrate. In this case, the transistor 310 may or may not be formed.

[0377] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be appropriately combined with other configuration examples or drawings.

[0378] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification and the like.

[0379] Embodiment 4 In this embodiment, a transistor that can be used in a display device according to one embodiment of the present invention will be described.

[0380] 27A, 27B, and 27C are a top view and a cross-sectional view of a transistor 500 that can be used in a display device according to one embodiment of the present invention. The transistor 500 can be used in the display device according to one embodiment of the present invention.

[0381] 27A is a top view of the transistor 500. Also, FIGS. 27B and 27C are cross-sectional views of the transistor 500. Here, FIG. 27B is a cross-sectional view of a portion indicated by the dashed dotted line A1-A2 in FIG. 27A and is also a cross-sectional view of the transistor 500 in the channel length direction. Also, FIG. 27C is a cross-sectional view of a portion indicated by the dashed dotted line A3-A4 in FIG. 27A and is also a cross-sectional view of the transistor 500 in the channel width direction. Note that some elements are omitted from the top view of FIG. 27A for clarity.

[0382] 27 , the transistor 500 includes a metal oxide 531a disposed on a substrate (not shown), a metal oxide 531b disposed on the metal oxide 531a, conductors 542a and 542b disposed spaced apart from each other on the metal oxide 531b, an insulator 580 disposed on the conductors 542a and 542b and having an opening formed between the conductors 542a and 542b, a conductor 560 disposed in the opening, and an insulator 550 disposed between the metal oxide 531b, the conductors 542a and 542b, and the insulator 580 and the conductor 560. Here, as shown in FIGS. 27B and 27C , the top surface of the conductor 560 preferably substantially coincides with the top surfaces of the insulators 550 and 580. Hereinafter, the metal oxides 531a and 531b may be collectively referred to as the metal oxide 531. In addition, the conductor 542a and the conductor 542b may be collectively referred to as the conductor 542.

[0383] 27 , the side surfaces of the conductors 542a and 542b facing the conductor 560 have a substantially vertical shape. Note that the transistor 500 shown in FIG. 27 is not limited to this, and the angle formed between the side surface and the bottom surface of the conductors 542a and 542b may be 10° to 80°, preferably 30° to 60°. Furthermore, the opposing side surfaces of the conductors 542a and 542b may have multiple surfaces.

[0384] Note that the transistor 500 has a structure in which two layers of the metal oxide 531a and the metal oxide 531b are stacked in the region where a channel is formed (hereinafter also referred to as the channel formation region) and in the vicinity thereof; however, one embodiment of the present invention is not limited to this structure. For example, the metal oxide 531b may have a single-layer structure or a stacked structure of three or more layers. Furthermore, each of the metal oxide 531a and the metal oxide 531b may have a stacked structure of two or more layers.

[0385] Here, the conductor 560 functions as the gate electrode of the transistor, and the conductors 542a and 542b function as source and drain electrodes, respectively. As described above, the conductor 560 is formed so as to be embedded in the opening of the insulator 580 and in the region sandwiched between the conductors 542a and 542b. Here, the arrangements of the conductors 560, 542a, and 542b are selected in a self-aligned manner with respect to the opening of the insulator 580. That is, in the transistor 500, the gate electrode can be positioned between the source and drain electrodes in a self-aligned manner. Therefore, the conductor 560 can be formed without providing a margin for alignment, thereby reducing the area occupied by the transistor 500. This allows for a high-resolution display device. Furthermore, the display device can have a narrow frame.

[0386] 27 , the conductor 560 preferably includes a conductor 560a provided inside the insulator 550 and a conductor 560b provided so as to be embedded inside the conductor 560a. Although the conductor 560 has a two-layer structure in FIG. 27 , one embodiment of the present invention is not limited to this. For example, the conductor 560 may have a single-layer structure or a stacked structure of three or more layers.

[0387] The transistor 500 preferably includes an insulator 514 disposed on a substrate (not shown), an insulator 516 disposed on the insulator 514, a conductor 505 disposed so as to be embedded in the insulator 516, an insulator 522 disposed on the insulator 516 and the conductor 505, and an insulator 524 disposed on the insulator 522. A metal oxide 531a is preferably disposed on the insulator 524.

[0388] 27 , it is preferable that an insulator 554 be disposed between the insulator 522, the insulator 524, the metal oxide 531a, the metal oxide 531b, the conductor 542a, the conductor 542b, and the insulator 550 and the insulator 580. Here, it is preferable that the insulator 554 be in contact with the side surface of the insulator 550, the top and side surfaces of the conductor 542a, the top and side surfaces of the conductor 542b, the side surfaces of the metal oxide 531a, the metal oxide 531b, and the insulator 524, and the top surface of the insulator 522, as shown in FIGS.

[0389] An insulator 574 functioning as an interlayer film and an insulator 581 are preferably provided over the transistor 500. Here, the insulator 574 is preferably provided in contact with top surfaces of the conductor 560, the insulator 550, and the insulator 580.

[0390] The insulators 522, 554, and 574 preferably have the function of suppressing the diffusion of hydrogen (e.g., at least one of hydrogen atoms and hydrogen molecules). For example, the insulators 522, 554, and 574 preferably have lower hydrogen permeability than the insulators 524, 550, and 580. The insulators 522 and 554 preferably have the function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules). For example, the insulators 522 and 554 preferably have lower oxygen permeability than the insulators 524, 550, and 580.

[0391] A conductor 545 (conductor 545a and conductor 545b) that is electrically connected to the transistor 500 and functions as a plug is preferably provided. Note that the insulator 541 (insulator 541a and insulator 541b) is provided in contact with the side surface of the conductor 545 that functions as a plug. That is, the insulator 541 is provided in contact with the inner walls of the openings of the insulators 554, 580, 574, and 581. Alternatively, a first conductor of the conductor 545 may be provided in contact with the side surface of the insulator 541, and a second conductor of the conductor 545 may be provided further inward. Here, the height of the top surface of the conductor 545 can be made approximately the same as the height of the top surface of the insulator 581. Note that the transistor 500 illustrates a structure in which the first conductor of the conductor 545 and the second conductor of the conductor 545 are stacked; however, one embodiment of the present invention is not limited to this. For example, the conductor 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 an ordinal number to indicate the order of formation.

[0392] In the transistor 500, a metal oxide that functions as an oxide semiconductor (hereinafter also referred to as an oxide semiconductor) is preferably used for the metal oxide 531 (the metal oxide 531a and the metal oxide 531b) including the channel formation region. For example, the 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.

[0393] The metal oxide preferably contains at least indium (In) or zinc (Zn). In particular, it is preferable that indium (In) and zinc (Zn) are contained. Furthermore, it is preferable that the element M is contained in addition to these. The element M can be 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). In particular, it is preferable that the element M is one or more of aluminum (Al), gallium (Ga), yttrium (Y), or tin (Sn). Furthermore, it is more preferable that the element M contains either or both of Ga and Sn.

[0394] Furthermore, the thickness of the metal oxide 531b in a region that does not overlap with the conductor 542 may be thinner than the thickness of the region that overlaps with the conductor 542. This is formed by removing part of the top surface of the metal oxide 531b when forming the conductors 542a and 542b. When a conductive film that will become the conductor 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 conductors 542a and 542b on the top surface of the metal oxide 531b can prevent a channel from being formed in that region.

[0395] According to one embodiment of the present invention, a display device with high definition can be provided by using a small-sized transistor. Alternatively, a display device with high luminance can be provided by using a transistor with high on-state current. Alternatively, a display device with high speed operation can be provided by using a transistor with stable electrical characteristics. Alternatively, a display device with high reliability can be provided by using a transistor with low off-state current.

[0396] A detailed structure of a transistor 500 that can be used in a display device according to one embodiment of the present invention will be described.

[0397] The conductor 505 is arranged to have a region overlapping with the metal oxide 531 and the conductor 560. The conductor 505 is preferably embedded in the insulator 516.

[0398] The conductor 505 includes a conductor 505a and a conductor 505b. The conductor 505a is provided in contact with the bottom surface and sidewall of an opening provided in the insulator 516. The conductor 505b is provided so as to be embedded in a recess formed in the conductor 505a. Here, the height of the upper surface of the conductor 505b is approximately the same as the height of the upper surface of the conductor 505a and the height of the upper surface of the insulator 516.

[0399] The conductor 505a may be, for example, a hydrogen atom, a hydrogen molecule, a water molecule, a nitrogen atom, a nitrogen molecule, or a nitrogen oxide molecule (e.g., N ２ O, NO, or NO ２ It is preferable to use a conductive material that has a function of suppressing the diffusion of impurities such as copper atoms, 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 and oxygen molecules, etc.).

[0400] By using a conductive material that can reduce hydrogen diffusion for the conductor 505a, it is possible to prevent impurities such as hydrogen contained in the conductor 505b from diffusing into the metal oxide 531 via, for example, the insulator 524. Furthermore, by using a conductive material that can reduce oxygen diffusion for the conductor 505a, it is possible to prevent the conductor 505b from being oxidized and its conductivity from decreasing. Examples of conductive materials that can reduce oxygen diffusion include titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, and ruthenium oxide. Therefore, the conductor 505a may be formed as a single layer or a stack of the above conductive materials. For example, the conductor 505a may be made of titanium nitride.

[0401] The conductor 505b is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component, for example, tungsten.

[0402] Here, the conductor 560 may function as a first gate (also referred to as a top gate) electrode. The conductor 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 conductor 505 independently of the potential applied to the conductor 560. ｔｈ In particular, applying a negative potential to the conductor 505 can control the V ｔｈ Therefore, when a negative potential is applied to the conductor 505, the drain current when the potential applied to the conductor 560 is 0 V can be made smaller than when no negative potential is applied.

[0403] The conductor 505 is preferably larger than the channel formation region of the metal oxide 531. In particular, as shown in Fig. 27C, the conductor 505 preferably extends also in a region outside the end portion intersecting with the channel width direction of the metal oxide 531. In other words, the conductor 505 and the conductor 560 preferably overlap with each other with an insulator interposed therebetween on the outside of the side surface of the metal oxide 531 in the channel width direction.

[0404] With the above structure, the channel formation region of the metal oxide 531 can be electrically surrounded by the electric field of the conductor 560 that functions as a first gate electrode and the electric field of the conductor 505 that functions as a second gate electrode.

[0405] 27C, the conductor 505 is extended to function as wiring. However, without being limited to this, a conductor functioning as wiring may be provided below the conductor 505.

[0406] The insulator 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 insulator 514 is a barrier insulating film that prevents impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules (e.g., 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 (the impurities are less likely to permeate). Alternatively, it is preferable to use an insulating material that has a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules, etc.) (the oxygen is less likely to permeate).

[0407] For example, it is preferable to use aluminum oxide, silicon nitride, or the like as the insulator 514. This can prevent impurities such as water or hydrogen from diffusing from the substrate side of the insulator 514 to the transistor 500 side. Alternatively, it can prevent oxygen contained in the insulator 524 or the like from diffusing to the substrate side of the insulator 514.

[0408] The insulators 516, 580, and 581, which function as interlayer films, preferably have a lower dielectric constant than the insulator 514. Using a material with a low dielectric constant as the interlayer film can reduce parasitic capacitance between wirings. For example, the insulators 516, 580, and 581 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, silicon oxide having vacancies, or the like as appropriate.

[0409] The insulators 522 and 524 function as gate insulators.

[0410] Here, the insulator 524 in contact with the metal oxide 531 preferably releases oxygen by heating. In this specification and the like, oxygen released by heating is sometimes referred to as excess oxygen. The insulator 524 may be formed using, for example, silicon oxide or silicon oxynitride as appropriate. By providing an insulator 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.

[0411] Specifically, an oxide material from which some oxygen is released by heating is preferably used as the insulator 524. The oxide from which oxygen is released by heating is an oxide from which the amount of released oxygen converted into oxygen atoms obtained by thermal desorption spectroscopy (TDS) analysis is 1.0×10 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.

[0412] The insulator 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, similar to the insulator 514. For example, the insulator 522 preferably has lower hydrogen permeability than the insulator 524. By surrounding the insulator 524, the metal oxide 531, the insulator 550, etc. with the insulators 522, 554, and 574, for example, impurities such as water or hydrogen can be prevented from entering the transistor 500 from the outside.

[0413] Furthermore, the insulator 522 preferably has a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules) (i.e., the oxygen is less likely to permeate). For example, the insulator 522 preferably has lower oxygen permeability than the insulator 524. The insulator 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 conductor 505 can be prevented from reacting with oxygen contained in the insulator 524 and the metal oxide 531.

[0414] The insulator 522 may be an insulating material containing oxides of one or both of aluminum and hafnium. Examples of the insulator containing oxides of one or both of aluminum and hafnium include aluminum oxide, hafnium oxide, and oxides containing aluminum and hafnium (hafnium aluminate). When the insulator 522 is formed using such a material, the insulator 522 functions as a layer that suppresses oxygen release from the metal oxide 531 and the intrusion of impurities such as hydrogen from the periphery of the transistor 500 into the metal oxide 531.

[0415] 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 insulators. Alternatively, these insulators may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be stacked on the above insulators.

[0416] The insulator 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 ３Insulators containing so-called high-k materials such as BST may be used in a single layer or a multilayer configuration. As transistors become smaller and more highly integrated, problems such as leakage current may occur due to the thinning of the gate insulator. By using a high-k material as the insulator that functions as the gate insulator, it is possible to reduce the gate potential during transistor operation while maintaining the physical film thickness.

[0417] The insulator 522 and the insulator 524 may have a layered structure of two or more layers. In this case, the insulator 522 and the insulator 524 are not limited to having a layered structure made of the same material, and may have a layered structure made of different materials. For example, an insulator similar to the insulator 524 may be provided below the insulator 522.

[0418] The metal oxide 531 includes a metal oxide 531a and a metal oxide 531b on the metal oxide 531a. By providing the metal oxide 531a below the metal oxide 531b, it is possible to suppress diffusion of impurities from structures formed below the metal oxide 531a to the metal oxide 531b.

[0419] Note that the metal oxide 531 preferably has a stacked structure of multiple oxide layers with different atomic ratios of the respective 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.

[0420] The energy of the conduction band minimum of the metal oxide 531a 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 is preferably smaller than the electron affinity of the metal oxide 531b.

[0421] Here, the energy level of the conduction band minimum changes smoothly at the junction between the metal oxides 531a and 531b. In other words, the energy level of the conduction band minimum at the junction between the metal oxides 531a and 531b changes continuously or can be said to be a continuous junction. To achieve this, it is advisable to reduce the defect level density of the mixed layer formed at the interface between the metal oxides 531a and 531b.

[0422] Specifically, when the metal oxide 531a and the metal oxide 531b have a common element (main component) other than oxygen, a mixed layer with a low density of defect states can be formed. For example, when the metal oxide 531b is an In—Ga—Zn oxide, the metal oxide 531a may be, for example, an In—Ga—Zn oxide, a Ga—Zn oxide, or gallium oxide.

[0423] Specifically, the metal oxide 531a may have an atomic ratio of In:Ga:Zn=1:3:4 or 1:1:0.5, and the metal oxide 531b may have an atomic ratio of In:Ga:Zn=1:1:1, 4:2:3, or 3:1:2.

[0424] In this case, the main carrier path is the metal oxide 531b. By configuring the metal oxide 531a as described above, the defect state density at the interface between the metal oxide 531a and the metal oxide 531b can be reduced. Therefore, the influence of interface scattering on carrier conduction is reduced, and the transistor 500 can achieve high on-state current and high frequency characteristics.

[0425] Conductors 542 (conductors 542a and 542b) functioning as a source electrode and a drain electrode are provided on the metal oxide 531b. The conductor 542 is preferably made of 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, or an alloy combining any of the above metal elements. 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, or an oxide containing lanthanum and nickel 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, or 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.

[0426] By providing the conductor 542 so as to be in contact with the metal oxide 531, the oxygen concentration may be reduced in the vicinity of the conductor 542 of the metal oxide 531. Furthermore, a metal compound layer containing the metal contained in the conductor 542 and components of the metal oxide 531 may be formed in the vicinity of the conductor 542 of the metal oxide 531. In such a case, the carrier concentration increases in the region of the metal oxide 531 in the vicinity of the conductor 542, and the region becomes a low-resistance region.

[0427] Here, the region between the conductor 542a and the conductor 542b is formed to overlap the opening of the insulator 580. This allows the conductor 560 to be arranged in a self-aligned manner between the conductor 542a and the conductor 542b.

[0428] The insulator 550 functions as a gate insulator. The insulator 550 is preferably disposed in contact with the top surface of the metal oxide 531b. The insulator 550 can be 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 or silicon oxynitride is preferable because it is stable to heat.

[0429] The insulator 550 preferably has a reduced concentration of impurities such as water or hydrogen, similar to the insulator 524. The thickness of the insulator 550 is preferably greater than or equal to 1 nm and less than or equal to 20 nm.

[0430] An insulator may be provided between the insulator 580, the insulator 554, the conductor 542, and the metal oxide 531b and the insulator 550. For example, aluminum oxide or hafnium oxide is preferably used as the insulator. By providing the insulator, for example, desorption of oxygen from the metal oxide 531b, excessive supply of oxygen to the metal oxide 531b, and oxidation of the conductor 542 can be suppressed.

[0431] A metal oxide may be provided between the insulator 550 and the conductor 560. The metal oxide preferably suppresses oxygen diffusion from the insulator 550 to the conductor 560. This can suppress oxidation of the conductor 560 due to oxygen in the insulator 550.

[0432] The metal oxide may function as part of the gate insulator. Therefore, when using, for example, silicon oxide or silicon oxynitride for the insulator 550, the metal oxide is preferably a high-k material with a high dielectric constant. By forming the gate insulator into a stacked structure of the insulator 550 and the metal oxide, a stacked structure that is thermally stable and has a high dielectric constant can be achieved. This makes it possible to reduce the gate potential applied during transistor operation while maintaining the physical thickness of the gate insulator. Furthermore, it is possible to reduce the equivalent oxide thickness (EOT) of the insulator functioning as the gate insulator.

[0433] Specifically, for example, a metal oxide containing one or more elements selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, magnesium, etc. can be used as the insulator 550. In particular, it is preferable to use an insulator containing an oxide of one or both of aluminum and hafnium, such as aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate).

[0434] Although the conductor 560 is shown as having a two-layer structure in FIG. 27, it may have a single-layer structure or a laminated structure of three or more layers.

[0435] The conductor 560a is made of the above-mentioned, for example, hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules (e.g., N ２ O, NO, or NO ２ It is preferable to use a conductor 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 and oxygen molecules).

[0436] The conductor 560a has a function of suppressing oxygen diffusion, which can suppress a decrease in conductivity due to oxidation of the conductor 560b caused by oxygen contained in the insulator 550. As a conductive material having a function of suppressing oxygen diffusion, it is preferable to use, for example, tantalum, tantalum nitride, ruthenium, or ruthenium oxide.

[0437] The conductor 560b is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. Furthermore, since the conductor 560 also functions as wiring, it is preferable to use a conductor with high conductivity. For example, a conductive material containing tungsten, copper, or aluminum as a main component can be used. Furthermore, the conductor 560b may have a layered structure, for example, a layered structure of titanium or titanium nitride and the above-mentioned conductive material.

[0438] 27A and 27C , in a region of the metal oxide 531b that does not overlap with the conductor 542, in other words, in the channel formation region of the metal oxide 531, the side surface of the metal oxide 531 is arranged to be covered with the conductor 560. This makes it easier for the electric field of the conductor 560, which functions as the first gate electrode, to act on the side surface of the metal oxide 531. This increases the on-state current of the transistor 500 and improves its frequency characteristics.

[0439] The insulator 554 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the transistor 500 from the insulator 580 side, similar to the insulator 514. For example, the insulator 554 preferably has lower hydrogen permeability than the insulator 524. Furthermore, as shown in FIGS. 27B and 27C , the insulator 554 preferably contacts the side surface of the insulator 550, the top and side surfaces of the conductor 542a, the top and side surfaces of the conductor 542b, the metal oxide 531a, the metal oxide 531b, and the side surfaces of the insulator 524. This structure can prevent hydrogen contained in the insulator 580 from entering the metal oxide 531 from the top or side surfaces of the conductor 542a, the conductor 542b, the metal oxide 531a, the metal oxide 531b, and the insulator 524.

[0440] Furthermore, the insulator 554 preferably has a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules) (i.e., the oxygen is less likely to permeate). For example, the insulator 554 preferably has lower oxygen permeability than the insulator 580 or the insulator 524.

[0441] The insulator 554 is preferably formed by a sputtering method. By forming the insulator 554 by a sputtering method in an oxygen-containing atmosphere, oxygen can be added to the insulator 524 near a region in contact with the insulator 554. This allows oxygen to be supplied from the region to the metal oxide 531 through the insulator 524. The insulator 554 has a function of suppressing upward diffusion of oxygen, thereby preventing oxygen from diffusing from the metal oxide 531 to the insulator 580. The insulator 522 has a function of suppressing downward diffusion of oxygen, 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.

[0442] For example, an insulator containing an oxide of one or both of aluminum and hafnium may be formed as the insulator 554. Note that as the insulator containing an oxide of one or both of aluminum and hafnium, for example, aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate) is preferably used.

[0443] The insulator 580 is provided over the insulator 524, the metal oxide 531, and the conductor 542 with the insulator 554 interposed therebetween. The insulator 580 preferably includes, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, 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. Silicon oxide and silicon oxynitride are particularly preferred because they are thermally stable. Materials such as silicon oxide, silicon oxynitride, or silicon oxide having vacancies are particularly preferred because they can easily form a region containing oxygen that is released by heating.

[0444] The concentration of impurities such as water or hydrogen is preferably reduced in the insulator 580. The top surface of the insulator 580 may be planarized.

[0445] Similar to the insulator 514, the insulator 574 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the insulator 580 from above. As the insulator 574, for example, an insulator that can be used for the insulator 514, the insulator 554, or the like can be used.

[0446] An insulator 581 functioning as an interlayer film is preferably provided over the insulator 574. Like the insulator 524, the insulator 581 preferably has a reduced concentration of impurities such as water or hydrogen.

[0447] The conductor 545a and the conductor 545b are arranged in openings formed in the insulator 581, the insulator 574, the insulator 580, and the insulator 554. The conductor 545a and the conductor 545b are provided opposite each other with the conductor 560 interposed therebetween. Note that the height of the top surfaces of the conductor 545a and the conductor 545b may be flush with the top surface of the insulator 581.

[0448] Note that insulator 541a is provided in contact with the inner walls of the openings of insulators 581, 574, 580, and 554, and a first conductor of conductor 545a is formed in contact with the side surface of insulator 541a. Conductor 542a is located on at least a portion of the bottom of the openings, and conductor 545a is in contact with conductor 542a. Similarly, insulator 541b is provided in contact with the inner walls of the openings of insulators 581, 574, 580, and 554, and a first conductor of conductor 545b is formed in contact with the side surface of insulator 541b. Conductor 542b is located on at least a portion of the bottom of the openings, and conductor 545b is in contact with conductor 542b.

[0449] The conductors 545a and 545b are preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. The conductors 545a and 545b may have a layered structure.

[0450] When the conductor 545 has a layered structure, the conductors in contact with the conductor 542, the insulator 554, the insulator 580, the insulator 574, and the insulator 581 preferably have the above-described function of suppressing the diffusion of impurities such as water or hydrogen. For example, tantalum, tantalum nitride, titanium, titanium nitride, ruthenium, or ruthenium oxide is preferably used. Furthermore, a conductive material that suppresses the diffusion of impurities such as water or hydrogen may be used in a single layer or a layered structure. The use of such a conductive material can suppress the absorption of oxygen added to the insulator 580 by the conductors 545a and 545b. Furthermore, impurities such as water or hydrogen from layers above the insulator 581 can be suppressed from entering the metal oxide 531 through the conductors 545a and 545b.

[0451] The insulators 541a and 541b may be, for example, an insulator that can be used for the insulator 554. The insulators 541a and 541b are provided in contact with the insulator 554, and thus can prevent impurities such as water or hydrogen from the insulator 580 or the like from being mixed into the metal oxide 531 through the conductors 545a and 545b. Furthermore, oxygen contained in the insulator 580 can be prevented from being absorbed by the conductors 545a and 545b.

[0452] Although not shown, a conductor functioning as a wiring may be disposed in contact with the top surface of the conductor 545a and the top surface of the conductor 545b. The conductor functioning as a wiring is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. The conductor may also have a layered structure, for example, a layered structure of titanium or titanium nitride and the above-mentioned conductive material. The conductor may be formed so as to be embedded in an opening provided in an insulator.

[0453] <Constituent Materials of Transistor> Constituent materials that can be used for the transistor will be described.

[0454] [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 glass substrates, quartz substrates, sapphire substrates, stabilized zirconia substrates (e.g., yttria-stabilized zirconia substrates), and resin substrates. 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 region within the aforementioned 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 containing metal nitrides or metal oxides. Further, there are substrates in which a conductor or a semiconductor is provided on an insulating substrate, substrates in which a conductor or an insulator is provided on a semiconductor substrate, and substrates in which a semiconductor or an insulator is provided on a conductor substrate. Alternatively, these substrates may be provided with elements. Examples of elements provided on the substrate include a capacitance element, a resistance element, a switching element, a light-emitting element, and a memory element.

[0455] [Insulator] Examples of the insulator include oxides, nitrides, oxynitrides, nitride oxides, metal oxides, metal oxynitrides, and metal nitride oxides, all of which have insulating properties.

[0456] For example, as transistors become more miniaturized and highly integrated, thinner gate insulators can cause problems such as leakage current. Using a high-k material for the insulator that functions as the gate insulator 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 insulator 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 insulator's function.

[0457] Examples of insulators with a high relative dielectric constant include gallium oxide, hafnium oxide, zirconium oxide, oxides having aluminum and hafnium, oxynitrides having aluminum and hafnium, oxides having silicon and hafnium, oxynitrides having silicon and hafnium, and nitrides having silicon and hafnium.

[0458] Examples of insulators with a low dielectric constant include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide doped with fluorine, silicon oxide doped with carbon, silicon oxide doped with carbon and nitrogen, silicon oxide having voids, or resin.

[0459] The electrical characteristics of a transistor including an oxide semiconductor can be stabilized by surrounding the transistor with an insulator (e.g., the insulator 514, the insulator 522, the insulator 554, the insulator 574, etc.) that has a function of suppressing the permeation of impurities such as hydrogen and oxygen. For example, the insulator that has a function of suppressing the permeation of impurities such as hydrogen and oxygen can be a single layer or a stack of insulators containing boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum, neodymium, hafnium, or tantalum. Specifically, the insulator that has a function of suppressing the permeation of impurities such as hydrogen and oxygen can be 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.

[0460] The insulator functioning as the gate insulator is preferably an insulator 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.

[0461] [Conductor] As the conductor, it is preferable to use, for example, a metal element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, and lanthanum, an alloy containing the above-mentioned metal element as a component, or an alloy combining the above-mentioned metal elements, etc. For example, it is preferable to use tantalum nitride, titanium nitride, tungsten, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, or an oxide containing lanthanum and nickel, etc. 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, or oxides containing lanthanum and nickel are preferable because they are conductive materials that are resistant to oxidation or materials that maintain conductivity even when absorbing oxygen. Also, semiconductors with high electrical conductivity, such as polycrystalline silicon containing impurity elements such as phosphorus, or silicides such as nickel silicide may be used.

[0462] A plurality of conductors formed from the above materials may be stacked. For example, a stacked structure may be formed by combining the above-mentioned material containing a metal element and a conductive material containing oxygen. A stacked structure may also be formed by combining the above-mentioned material containing a metal element and a conductive material containing nitrogen. A stacked structure may also be formed by combining the above-mentioned material containing a metal element, a conductive material containing oxygen, and a conductive material containing nitrogen.

[0463] When a metal oxide is used for the channel formation region of a transistor, a conductor functioning as a gate electrode preferably has a stacked structure of a combination of 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.

[0464] In particular, it is preferable to use a conductive material containing oxygen and a metal element contained in the metal oxide in which the channel is formed as a conductor functioning as a gate electrode. Alternatively, a conductive material containing the aforementioned 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 doped with silicon may be used. Alternatively, indium gallium zinc oxide containing nitrogen may be used. Using such a material may allow hydrogen contained in the metal oxide in which the channel is formed to be captured. Alternatively, hydrogen introduced from an external insulator, for example, may be captured.

[0465] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification and the like.

[0466] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0467] Embodiment 5 In this embodiment, a metal oxide (hereinafter also referred to as an oxide semiconductor) that can be used for the OS transistor described in the above embodiment will be described.

[0468] The metal oxide used in the OS transistor preferably contains at least indium or zinc, and more preferably contains indium and zinc. For example, the metal oxide preferably contains indium, M (M is one or more selected from gallium, aluminum, yttrium, tin, silicon, boron, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt), and zinc. In particular, M is preferably one or more selected from gallium, aluminum, yttrium, and tin, and more preferably gallium.

[0469] The metal oxide can be formed by, for example, a sputtering method, a chemical vapor deposition (CVD) method such as a metal organic chemical vapor deposition (MOCVD) method, or an atomic layer deposition (ALD) method.

[0470] Hereinafter, an oxide containing indium (In), gallium (Ga), and zinc (Zn) will be described as an example of a metal oxide. Note that an oxide containing indium (In), gallium (Ga), and zinc (Zn) may be referred to as an In—Ga—Zn oxide.

[0471] <Classification of Crystal Structure> Examples of the crystal structure of an oxide semiconductor include amorphous (including completely amorphous), c-axis-aligned crystalline line (CAAC), nanocrystalline line (nc), cloud-aligned composite (CAC), single crystal, and polycrystalline.

[0472] The crystalline structure of a film or substrate can be evaluated using an X-ray diffraction (XRD) spectrum. For example, it can be evaluated using an XRD spectrum obtained by GIXD (Grazing-Incident XRD) measurement. The GIXD method is also called the thin film method or the Seemann-Bohlin method. In the following, the XRD spectrum obtained by GIXD measurement may be simply referred to as the XRD spectrum.

[0473] For example, in the case of a quartz glass substrate, the peak shape of the XRD spectrum is almost symmetrical. On the other hand, in the case of an In-Ga-Zn oxide film having a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical peak shape of the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0474] Furthermore, the crystalline structure of a film or substrate can be evaluated using a diffraction pattern (also called a nanobeam electron diffraction pattern) observed by nanobeam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. Furthermore, a spot-like pattern is observed in the diffraction pattern of an In—Ga—Zn oxide film formed at room temperature, rather than a halo. Therefore, an In—Ga—Zn oxide film formed at room temperature is neither single-crystal nor polycrystalline, nor in an amorphous state, but in an intermediate state. Therefore, it is difficult to conclude that it is in an amorphous state.

[0475] [Structure of Oxide Semiconductor] Note that oxide semiconductors may be classified differently from the above when focusing on their structure. For example, oxide semiconductors are divided 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. In addition, examples of non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, pseudo-amorphous-like oxide semiconductors (a-like OSs), and amorphous oxide semiconductors.

[0476] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0477] [CAAC-OS] A CAAC-OS is an oxide semiconductor having multiple crystalline regions, each of which has a c-axis aligned in a specific direction. The specific direction is the thickness direction of the CAAC-OS film, the normal direction 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.

[0478] 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 multiple minute crystals, the maximum diameter of the crystalline region may be several tens of nanometers.

[0479] In addition, in an In—Ga—Zn oxide, 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 gallium (Ga), zinc (Zn), and oxygen (hereinafter referred to as a (Ga, Zn) layer) are stacked. Note that indium and gallium are mutually substituted. Therefore, the (Ga, Zn) layer may contain indium. The In layer may contain gallium. The In layer may contain zinc. The layered structure is observed as a lattice image in a high-resolution transmission electron microscope (TEM) image, for example.

[0480] 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, for example, the type or composition of metal elements constituting the CAAC-OS.

[0481] 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).

[0482] 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 or heptagonal lattice arrangement, for example. It is difficult to identify clear grain boundaries in the CAAC-OS even near the distortion. This indicates that the distortion in the lattice arrangement suppresses the formation of grain boundaries. This may be because the CAAC-OS can tolerate distortion due to, for example, the lack of a dense arrangement of oxygen atoms in the a-b plane direction and the change in interatomic bond distance caused by metal atom substitution.

[0483] Note that a crystal structure in which clear grain boundaries are observed is called polycrystalline. The grain boundaries act as recombination centers, and carriers are likely to be captured, resulting in, for example, 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.

[0484] 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, for example, the inclusion of impurities or the generation of defects, the CAAC-OS can also be said to be an oxide semiconductor with few impurities and defects (e.g., oxygen vacancies). 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.

[0485] [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.

[0486] [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.

[0487] [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.

[0488] [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.

[0489] 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.

[0490] 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.

[0491] Specifically, the first region is a region whose main component is, for example, indium oxide or indium zinc oxide. The second region is a region whose main component is, for example, gallium oxide or gallium zinc oxide. 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.

[0492] It may be difficult to observe a clear boundary between the first region and the second region.

[0493] Furthermore, CAC-OS in In—Ga—Zn oxide refers to a structure in which a mosaic of regions containing Ga as the main component and regions containing In as the main component are randomly arranged in a material composition containing In, Ga, Zn, and O. Therefore, it is presumed that CAC-OS has a structure in which metal elements are distributed nonuniformly.

[0494] The CAC-OS can be formed by sputtering, for example, without intentionally heating the substrate. When forming the CAC-OS by sputtering, any one or more of an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. The lower the flow rate of oxygen gas relative to the total flow rate of deposition gas during deposition, the more preferable it is. For example, the flow rate of oxygen gas relative to the total flow rate of deposition gas during deposition is set to 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0495] Furthermore, 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.

[0496] Here, the first region has higher conductivity than the second region. That is, the flow of carriers through the first region causes the metal oxide to exhibit conductivity. Therefore, the first region is distributed in a cloud-like manner in the metal oxide, thereby achieving a high field-effect mobility (μ).

[0497] On the other hand, the second region has higher insulating properties than the first region. That is, the second region is distributed in the metal oxide, thereby suppressing leakage current.

[0498] Therefore, 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, so that the CAC-OS can be given a switching function (a function of turning on or off a transistor). In other words, a CAC-OS has a conductive function in a part of the material and an insulating function in a part of the material, and the entire material functions as a semiconductor. 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.

[0499] Furthermore, a transistor using the CAC-OS has high reliability, and therefore, the CAC-OS is ideal for various semiconductor devices such as display devices.

[0500] 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.

[0501] <Transistor Having Oxide Semiconductor> Next, a case where the oxide semiconductor is used for a transistor will be described.

[0502] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0503] 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.

[0504] For the transistor, an oxide semiconductor having a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 １７ cm −３ Below 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 That is all. Note that in order to reduce the carrier concentration in an oxide semiconductor, the density of defect states in the oxide semiconductor may be reduced by reducing the impurity concentration in the oxide semiconductor. 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.

[0505] A highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor has a low density of defect states, and therefore may also have a low density of trap states.

[0506] 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.

[0507] Therefore, reducing the impurity concentration in the oxide semiconductor is effective for stabilizing the electrical characteristics of a transistor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in adjacent films. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon. Note that the term "impurity" in an oxide semiconductor refers to, for example, any element other than the main component constituting the oxide semiconductor. For example, an element with a concentration of less than 0.1 atomic % can be considered an impurity.

[0508] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0509] When an oxide semiconductor contains silicon or carbon, which is one of Group 14 elements, defect levels are formed in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) is set to 2×10 １８ atoms / cm ３ Below 2 × 10, preferably １７ atoms / cm ３ The following applies.

[0510] When an oxide semiconductor contains an alkali metal or an alkaline earth metal, defect levels may be formed and carriers may be generated. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal 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:

[0511] When nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends 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 measured to be 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 １７atoms / cm ３ Do the following:

[0512] 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 obtained by SIMS is measured to be 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.

[0513] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0514] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0515] 10: display device, 11: light source, 12: optical system, 13: optical device, 14: housing, 14a: opening, 14b: opening, 20: eyeball, 21: mirror, 22: mirror, 23: lens, 24: mirror, 25: lens, 31: light, 32: light, 33: light, 50: sensor unit, 51: sensor unit, 52: sensor area, 60: display area, 61: light-emitting element, 61R: light-emitting element, 61G: light-emitting element, 61B: light-emitting element, 61IR: light-emitting element, 62: light-receiving element, 70: display device, 80: pixel, 95: display area, 100: electronic device, 101: housing, 103: wearing unit, 104: battery, 105: voltage generation unit, 106: control unit, 107: communication unit, 108: antenna, 121: earphone, 122: acoustic device, 130: control unit, 131: bus line, 140: calculation unit, 141: neural network, 150: memory unit, 160: input / output unit, 170: line of sight detection unit, 180: display device, 188: eyeball, 190: light emitting element, 191: light receiving element, 230: pixel, 232: peripheral circuit area, 233: peripheral circuit area, 234: functional circuit area, 236: wiring, 237: wiring, 240: capacitance, 290: pixel, 292: peripheral circuit region, 293: peripheral circuit region, 296: wiring, 297: wiring, 310: transistor, 320: transistor, 370R: light-emitting element, 370G: light-emitting element, 370B: light-emitting element, 370IR: light-emitting element, 370PD: light-receiving element, 380A: display device, 431: pixel circuit, 432: light-emitting element, 433: capacitor, 434: transistor, 435: wiring, 436: transistor, 437: wiring, 438: transistor, 491: pixel circuit, 492: light-receiving element, 493: transistor, 494: transistor, 495 : wiring, 496: transistor, 497: wiring, 498: transistor, 499: wiring, 500: transistor, DL_n: signal line, GL_m: scanning line, RS_p: row selection line, SE_p: row selection line, TX_p: row selection line, VL_a: potential supply line, VL_b: potential supply line, VL_c: potential supply line, VL_d: potential supply line, VL_e: potential supply line, WX_q: signal line, G: focus point, S1: area, S2: area, S3: area, S210: step, S211: step, S212: step, S213: step, S214: step

Claims

1. A display device and an optical system are provided, the display device includes a display area and a sensor area; the optical system includes a first mirror and a second mirror; the first mirror has a first surface and a second surface; the display area has a function of emitting a first light, the first mirror is provided on an optical path of the first light, and has a function of transmitting the first light incident on the first surface to the second surface, and a function of reflecting the second light incident on the second surface; the second mirror is provided on an optical path of the second light and has a function of reflecting the second light, the sensor region has a function of detecting the second light via the first mirror and the second mirror. optical equipment.

2. In claim 1, the optical system includes a light source; the light source has a function of emitting a third light, the second light is reflected light from an object irradiated with the third light; optical equipment.

3. In claim 1, The display device includes a light source; the light source has a function of emitting a third light, the second light is reflected light from an object irradiated with the third light; optical equipment.

4. In claim 2 or claim 3, the third light is infrared light; optical equipment.

5. In any one of claims 1 to 3, The sensor area is provided so as to overlap the display area. optical equipment.

6. In any one of claims 1 to 3, the optical system includes a first lens; the first lens is provided on an optical path of the first light and has a function of controlling the optical path of the first light. optical equipment.

7. In any one of claims 1 to 3, the display device includes a second lens; the second lens is provided between the second mirror and the sensor area and has a function of controlling an optical path of the second light. optical equipment.

8. In any one of claims 1 to 3, the display device comprises a pinhole; the pinhole is provided between the second mirror and the sensor area and has a function of controlling an optical path of the second light. optical equipment.

9. In any one of claims 1 to 3, the display device includes a line-of-sight detection unit, The line-of-sight detection unit has a function of detecting the line of sight of the user using image data acquired in the sensor area. optical equipment.