Optical devices

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

[Technical Field]

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

[0002] It should be noted that one aspect of the present invention is not limited to the above-mentioned technical field. The technical field of one aspect of the invention disclosed herein relates to a product, a method, a driving method, or a manufacturing method. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. More specifically, examples of the technical fields of one aspect of the present invention disclosed herein include semiconductor devices, display devices, light-emitting devices, energy storage devices, optical devices, imaging devices, memory devices, signal processing devices, electronic devices, lighting devices, input devices, input / output devices, methods for driving them, or methods for manufacturing them. [Background technology]

[0003] In recent years, electronic devices for virtual reality (VR) or augmented reality (AR) have attracted attention. Furthermore, electronic devices for VR or AR equipped with eye-tracking capabilities are being developed. Electronic devices for VR or AR with eye-tracking capabilities can be applied to, for example, consumer behavior analysis, image processing, avatar creation, or eye-based manipulation.

[0004] For example, Patent Document 1 discloses an electronic device for VR or AR equipped with an eye-tracking function. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2019 / 158709 [Overview of the project] [Problems that the invention aims to solve]

[0006] In an electronic device for VR or AR provided with a line-of-sight detection function, it is necessary to provide an imaging system (e.g., an image sensor, a control IC, etc.) in addition to a display system (e.g., a display, a driver, etc.). Further, it is necessary to appropriately adjust the optical system in accordance with the positional relationship between the eyes of a user of the electronic device, and the display system and the imaging system.

[0007] One aspect of the present invention has as one of its objects to provide a miniaturized optical device or electronic device. Alternatively, one aspect of the present invention has as one of its objects to provide a miniaturized optical device or electronic device provided with a line-of-sight detection function. Alternatively, one aspect of the present invention has as one of its objects to provide a novel optical device or electronic device. Alternatively, one aspect of the present invention has as one of its objects to provide a novel optical device or electronic device provided with a line-of-sight detection function.

[0008] Note that the description of these problems does not preclude the existence of other problems. One aspect of the present invention is not required to solve all of these problems. Problems other than these can be extracted from the description of the present specification, the drawings, the claims, or the like. [Means for Solving the Problem]

[0009] (1) One aspect of the present invention is an optical device including a display device and an optical system, 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 an 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) Furthermore, in (1) above, the optical system may be an optical device that includes a light source, the light source has the function of emitting a third light, and the second light is reflected light from the object to which the third light was irradiated.

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

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

[0013] (5) Furthermore, in any one of the above (1) to (4), the sensor area may be provided overlapping with the display area.

[0014] (6) Furthermore, in any one of (1) to (5) above, the optical system may include a first lens, the first lens may be located on the optical path of the first light, and may have a function to control the optical path of the first light.

[0015] (7) Furthermore, in any one of (1) to (6) above, the display device may include a second lens, the second lens being provided between the second mirror and the sensor area, and having a function to control the optical path of the second light.

[0016] (8) Furthermore, in any one of (1) to (6) above, the display device may include a pinhole, the pinhole being located between the second mirror and the sensor area, and having a function to control the optical path of the second light.

[0017] (9) Furthermore, in any one of the above (1) to (8), the display device may include a gaze detection unit, and the gaze detection unit may have a function to detect the user's gaze using image data acquired in the sensor area. [Effects of the Invention]

[0018] One aspect of the present invention can provide a miniaturized optical device or electronic device. Alternatively, one aspect of the present invention can provide a miniaturized optical device or electronic device equipped with a gaze detection function. Alternatively, one aspect of the present invention can provide a novel optical device or electronic device. Alternatively, one aspect of the present invention can provide a novel optical device or electronic device equipped with a gaze detection function.

[0019] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from this specification, the drawings, or the claims. [Brief explanation of the drawing]

[0020] Figures 1A and 1B illustrate examples of electronic device configurations. Figure 2 illustrates an example of the configuration of an optical device. Figure 3 illustrates an example of the configuration of an optical device. Figures 4A and 4B illustrate examples of the configuration of a display device. Figure 5 illustrates an example of the configuration of an optical device. Figure 6 illustrates an example of a display device configuration. Figure 7 illustrates an example of the configuration of an optical device. Figures 8A and 8B illustrate examples of display device configurations. Figure 9 illustrates an example of a display device configuration. Figures 10A and 10B illustrate an example of the configuration of a display device. Figure 11 illustrates an example of a display device configuration. Figures 12A and 12B illustrate examples of the operation of electronic equipment. Figure 13 is a flowchart illustrating an example of the operation of an electronic device. Figures 14A and 14B show examples of display device configurations. Figures 15A and 15B show examples of display device configurations. Figures 16A and 16B show examples of display device configurations. Figures 17A and 17B show examples of display device configurations. Figures 18A and 18B show examples of display device configurations. Figures 19A and 19B show examples of display device configurations. Figures 20A to 20E show examples of display device configurations. Figures 21A and 21B show examples of display device configurations. Figures 22A and 22B show examples of display device configurations. Figures 23A and 23B show examples of display device configurations. Figures 24A to 24D show examples of the configuration of a light-emitting element. Figure 25 shows an example of a display device configuration. Figure 26 shows an example of a display device configuration. Figure 27A is a top view showing an example of a transistor configuration. Figures 27B and 27C are cross-sectional views showing an example of a transistor configuration. [Modes for carrying out the invention]

[0021] In this specification, a semiconductor device refers to a device that utilizes semiconductor properties, such as a circuit containing semiconductor elements (e.g., transistors, diodes, or photodiodes), or a device having such a circuit. It also refers to any device that can function by utilizing semiconductor properties. For example, integrated circuits, chips equipped with integrated circuits, or electronic components with chips housed in a package are examples of semiconductor devices. Furthermore, for example, memory devices, display devices, light-emitting devices, lighting devices, or electronic devices are themselves semiconductor devices and may also contain semiconductor devices.

[0022] Furthermore, where it is stated in this specification that X and Y are connected, this specification discloses the cases in which X and Y are electrically connected, functionally connected, and directly connected. Therefore, it is not limited to predetermined connection relationships, such as those shown in the figures or text, but also includes connection relationships other than those shown in the figures or text. X and Y are, respectively, objects (e.g., devices, elements, circuits, wiring, electrodes, terminals, conductive films, or layers).

[0023] One example of a case where X and Y are electrically connected is that one or more elements that enable the electrical connection between X and Y (e.g., switches, transistors, capacitive elements, inductors, resistors, diodes, display devices, light-emitting devices, or loads) can be connected between X and Y.

[0024] One example of a functional connection between X and Y is when one or more circuits that enable the functional connection between X and Y (e.g., logic circuits (e.g., inverters, NAND gates, or NOR gates), signal conversion circuits (e.g., digital-to-analog conversion circuits, analog-to-digital conversion circuits, or gamma correction circuits), potential level conversion circuits (e.g., power supply circuits (e.g., boost circuits, or buck circuits), or level shifter circuits that change the potential level of a signal), voltage sources, current sources, switching circuits, amplification circuits (e.g., circuits that can increase signal amplitude or current, such as operational amplifiers, differential amplifiers, source follower circuits, or buffer circuits), signal generation circuits, memory circuits, or control circuits) can be connected between X and Y.

[0025] Furthermore, when it is explicitly stated that X and Y are electrically connected, this includes both cases where X and Y are electrically connected (i.e., connected with another element or circuit in between) and cases where X and Y are directly connected (i.e., connected without another element or circuit in between).

[0026] Furthermore, it can be expressed as, for example, "X, Y, the source (or first terminal, etc.) and drain (or second terminal, etc.) of the transistor are electrically connected to each other, and the connection is 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." Alternatively, it can be expressed as, "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." Alternatively, it can be expressed as, "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 similar notation to these examples to define the order of connections in a circuit configuration, the source (or first terminal, etc.) and drain (or second terminal, etc.) of a transistor can be distinguished and their technical scope determined. Note that these notational methods are examples only and are not limited to them. Here, X and Y are objects (e.g., devices, elements, circuits, wiring, electrodes, terminals, conductive films, or layers, etc.).

[0027] Even if independent components are shown as electrically connected in a circuit diagram, a single component may possess the functions of multiple components. For example, if part of a wiring also functions as an electrode, a single conductive film possesses the functions of both the wiring and the electrode. Therefore, in this specification, "electrically connected" includes cases where a single conductive film possesses the functions of multiple components.

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

[0029] Furthermore, when wiring is used as a resistive element, the resistance value of the resistive element may be determined by the length of the wiring. Alternatively, the resistive element may use a conductor with a different resistivity than the conductor used as the wiring. Or, when a semiconductor is used as a resistive element, the resistance value of the resistive element may be determined by doping the semiconductor with impurities.

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

[0031] Furthermore, in this specification, a transistor has three terminals called the gate, source, and drain. The gate is a control terminal that controls the amount of current flowing between the source and drain. The two terminals that function as either the source or the drain are the input and output terminals of the transistor. Depending on the conductivity type of the transistor (n-channel or p-channel) and the potential difference between the three terminals of the transistor, one of the two input and output terminals becomes the source and the other becomes the drain. For this reason, in this specification, the terms "source" and "drain" can be used interchangeably. Also, in this specification, when describing the connection relationships of a transistor, the notation "one of the source or drain" (or the first electrode or first terminal) or "the other of the source or drain" (or the second electrode or second terminal) is used. Note that, depending on the structure, a transistor may have a back gate in addition to the three terminals described above. In this case, in this specification, one of the gate or back gate of the transistor may be called the first gate, and the other of the gate or back gate of the transistor may be called the second gate. Furthermore, in the same transistor, the terms "gate" and "back gate" may be interchangeable. Furthermore, if a transistor has three or more gates, in this specification, each gate may be referred to as, for example, the first gate, the second gate, or the third gate.

[0032] Furthermore, in this specification, the term "node" can be replaced with other terms such as "terminal," "wiring," "electrode," "conductive layer," "conductor," or "impurity region," depending on the circuit configuration or device structure. Also, terms such as "terminal" or "wiring" can be replaced with "node."

[0033] Furthermore, in this specification, "voltage" and "potential" may be used interchangeably as appropriate. "Voltage" is the potential difference from a reference potential. For example, if the reference potential is the ground potential (earth potential), then "voltage" can be replaced with "potential." Note that the ground potential does not necessarily mean 0V. Also, potential is relative. That is, when the reference potential changes, the potential applied to wiring, the potential applied to a circuit, or the potential output from a circuit also changes.

[0034] Furthermore, in this specification, the terms "high-level potential" (also referred to as "high-level potential," "H potential," or "H") or "low-level potential" (also referred to as "low-level potential," "L potential," or "L") do not mean specific potentials. For example, if two wires are both described as "functioning as wires that supply a high-level potential," the high-level potentials provided by each wire do not have to be equal. Similarly, if two wires are both described as "functioning as wires that supply a low-level potential," the low-level potentials provided by each wire do not have to be equal.

[0035] Furthermore, in this specification, "electric current" refers to the phenomenon of electric charge movement (electrical conduction). For example, the statement "electrical conduction of positively charged elements is occurring" can be rephrased as "electrical conduction of negatively charged elements is occurring in the opposite direction." Therefore, in this specification, unless otherwise specified, "electric current" refers to the phenomenon of electric charge movement (electrical conduction) associated with the movement of carriers. Carriers here include, for example, electrons, holes, anions, cations, or complex ions. Note that carriers differ depending on the system through which the current flows (for example, semiconductors, metals, electrolytes, or in a vacuum). Also, for example, the "direction of current" in wiring is the direction in which positive carriers move and is expressed as a positive current quantity. In other words, the direction in which negative carriers move is the opposite direction to the direction of current and is expressed as a negative current quantity. Therefore, in this specification, if there is no indication of the positive or negative (or direction) of the current, a statement such as "current flows from element A to element B" may be rephrased as, for example, "current flows from element B to element A." Similarly, a statement such as "current is input to element A" may be rephrased as "current is output from element A."

[0036] Furthermore, in this specification, the ordinal numbers "first," "second," or "third" are used to avoid confusion of constituent elements. Therefore, they do not limit the number of constituent elements, nor do they limit the order of the constituent elements. For example, a constituent element referred to as "first" in one embodiment of this specification may be referred to as "second" in another embodiment or in the claims. Also, for example, a constituent element 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, phrases indicating arrangement, such as "above," "below," "upward," or "downward," are sometimes used for convenience to explain the positional relationships between components with reference to the drawings. The positional relationships between components change as appropriate depending on the direction in which each component is depicted. Therefore, the phrases indicating arrangement described in this specification are not limited to those described and can be appropriately rephrased depending on the situation. For example, the expression "insulator located on the upper surface of the conductor" can be rephrased as "insulator located on the lower surface of the conductor" by rotating the orientation of the drawing by 180 degrees. Similarly, the expression "insulator located on the upper surface of the conductor" can be rephrased as "insulator located on the left (or right) side of the conductor" by rotating the orientation of the drawing by 90 degrees.

[0038] Furthermore, the terms "above" or "below" do not limit the positional relationship of the components to being directly above or below each other and in direct contact. For example, the expression "electrode B on insulating layer A" does not require that electrode B be formed in direct contact with insulating layer A, and does not exclude cases where other components are included between insulating layer A and electrode B.

[0039] Furthermore, in this specification, terms such as "overlapping" do not limit the state of the components, such as the stacking order. For example, the expression "electrode B overlapping insulating layer A" is not limited to a state in which electrode B is formed on top of insulating layer A. The expression "electrode B overlapping insulating layer A" does not exclude, for example, a state in which electrode B is formed below insulating layer A, or a state in which electrode B is formed to the right (or left) of insulating layer A.

[0040] Furthermore, in this specification, the terms "adjacent" or "proximity" are not limited to direct contact between components. For example, the expression "electrode B adjacent to insulating layer A" does not require that insulating layer A and electrode B be formed in direct contact, and does not exclude cases where other components are included between insulating layer A and electrode B.

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

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

[0043] Furthermore, in this specification, terms such as "wiring," "signal line," or "power line" may be interchangeable depending on the context. For example, the term "wiring" may be changed to the term "signal line." Similarly, the term "wiring" may be changed to the term "power line." The same applies in reverse; for example, terms such as "signal line" or "power line" may be changed to the term "wiring." Similarly, terms such as "power line" may be changed to the term "signal line." Similarly, the same applies in reverse; for example, terms such as "signal line" may be changed to the term "power line." Furthermore, the term "potential" applied to wiring may be changed to the term "signal," depending on the context. Similarly, the same applies in reverse; for example, terms such as "signal" may be changed to the term "potential."

[0044] Furthermore, in this specification, "switch" refers to a device having multiple terminals and a function to switch (select) between continuity and non-continuity between those terminals. For example, if a switch has two terminals and there is continuity between both terminals, the switch is said to be in a "conductive state" or "on state." If there is no continuity between both terminals, the switch is said to be in a "non-conductive state" or "off state." Note that the act of switching the switch to either a continuative or non-conductive state, or maintaining either a continuative or non-conductive state, may be referred to as "controlling the continuity state."

[0045] In short, a switch is a device that controls whether or not an electric current flows. Alternatively, a switch is a device that selects and switches the path through which an electric current flows. Examples of switches include electrical switches and mechanical switches. In other words, a switch can be anything that can control an electric current, and is not limited to any particular type.

[0046] Furthermore, there are types of switches that are normally non-conductive and can become conductive by controlling the conductive state; these switches are sometimes called "A-contacts." Also, there are types of switches that are normally conductive and can become non-conductive by controlling the conductive state; these switches are sometimes called "B-contacts."

[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 "conducting state" or "on state" of the transistor refers to a state in which the source and drain electrodes of the transistor can be considered to be electrically short-circuited. Conversely, the "non-conducting state" or "off state" of the transistor refers to a state in which the source and drain electrodes of the transistor can be considered to be electrically disconnected. When a transistor is used simply as a switch, the polarity (conductivity type) of the transistor is not particularly limited.

[0048] One example of a mechanical switch is a switch using MEMS (Micro-Electro-Mechanical Systems) technology. This switch has mechanically movable electrodes, and the movement of these electrodes selects between a conductive state and a non-conductive state.

[0049] In this specification, "parallel" means a state in which two lines are positioned at an angle of -10° or more and 10° or less. Therefore, the case of -5° or more and 5° or less is also included. Furthermore, "approximately parallel" or "roughly parallel" means a state in which two lines are positioned at an angle of -30° or more and 30° or less. Furthermore, "perpendicular" means a state in which two lines are positioned at an angle of 80° or more and 100° or less. Therefore, the case of 85° or more and 95° or less is also included. Furthermore, "approximately perpendicular" or "roughly perpendicular" means a state in which two lines are positioned at an angle of 60° or more and 120° or less.

[0050] In this specification, when referring to count values ​​and measured values, or to objects, methods, and events that can be converted to count values ​​or measured values, terms such as "identical," "same," "equal," or "uniform" (including synonyms thereof) shall include an error margin of plus or minus 20%, unless otherwise explicitly stated.

[0051] In this specification, semiconductor impurities refer to elements other than the main components constituting the semiconductor layer. For example, elements with a concentration of less than 0.1 atomic percent are impurities. The presence of impurities in a semiconductor can cause, for example, an increase in the defect level density, a decrease in carrier mobility, or a decrease in crystallinity. When the semiconductor is an oxide semiconductor, impurities that alter the properties 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 components of the oxide semiconductor. In particular, examples include hydrogen (which is also found in water), lithium, sodium, silicon, boron, phosphorus, carbon, or nitrogen. Furthermore, when the semiconductor is a silicon layer, impurities that alter the properties of the semiconductor include, for example, Group 1 elements (excluding oxygen and hydrogen), Group 2 elements, Group 13 elements, or Group 15 elements.

[0052] In this specification, "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), or oxide semiconductors (also called oxide semiconductors or simply OS). For example, when a metal oxide is used in the semiconductor layer of a transistor, the metal oxide may be referred to as an oxide semiconductor. In other words, when a metal oxide is used to constitute the channel-forming region of a transistor having at least one of amplification, rectification, and switching functions, the metal oxide can be referred to as a metal oxide semiconductor. Furthermore, the term "OS transistor" can be replaced with "a transistor having a metal oxide or oxide semiconductor."

[0053] Furthermore, in this specification, metal oxides containing nitrogen may also be collectively referred to as metal oxides. Additionally, metal oxides containing nitrogen may be called metal oxynitrides.

[0054] Furthermore, in this specification, the configurations shown in each embodiment can be appropriately combined with the configurations shown in other embodiments to form one aspect of the present invention. Also, if multiple configuration examples are shown within one embodiment, these configuration examples can be appropriately combined.

[0055] Embodiments described herein will be explained with reference to the drawings. However, embodiments can be implemented in many different ways. Therefore, it will be easily understood by those skilled in the art that their form and details can be changed in various ways without departing from the spirit and scope. Accordingly, the present invention is not to be construed as being limited to the contents of the embodiments. In addition, in drawings illustrating embodiments, the same reference numerals may be used in common across different drawings for parts that are the same or have similar functions in the configuration of the invention, thereby omitting repeated explanations. Also, in drawings, when referring to similar functions, the same hatching pattern may be used and reference numerals may not be assigned. Furthermore, in order to facilitate understanding, some components may be omitted in drawings, for example, in perspective views or top views. Also, notations such as hatching patterns may be omitted in drawings.

[0056] Furthermore, in the drawings and other illustrations relating to this specification, the size, layer thickness, or area may be exaggerated for clarity. Therefore, the drawings are not necessarily limited to, for example, their size or aspect ratio. Moreover, the drawings are schematic representations of ideal examples and are not limited to, for example, the shapes or values ​​shown in the drawings. For example, they may include variations in signals, voltages, or currents due to noise, or variations in signals, voltages, or currents due to timing differences.

[0057] Furthermore, in drawings and other illustrations relating to this specification, arrows indicating the X, Y, and Z directions may be included. In this specification, the "X direction" is the direction along the X-axis, and unless explicitly stated, forward and reverse directions may not be distinguished. The same applies to the "Y direction" and "Z direction." Also, the X, Y, and Z directions are directions that intersect each other. More specifically, the X, Y, and Z directions are directions that are orthogonal to each other. In this specification, one of the X, Y, or Z directions may be referred to as the "first direction" or "first direction." Another 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, when the same reference numeral is used for multiple elements, and especially when it is necessary to distinguish them, an identifying numeral such as "A", "b", "_1", "[n]", or "[m,n]" may be added to the reference numeral. 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 something common to light-emitting elements 61R, 61G, and 61B, or when it is not necessary to distinguish between them, they may simply be referred to as "light-emitting element 61".

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

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

[0061] Furthermore, the electronic device 100 includes an optical device 13 (optical device 13R and optical device 13L) inside the housing 101. In addition, the optical device 13 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). A detailed description of the configuration examples of the optical device 13, display device 10, light source 11, and optical system 12 will be given later.

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

[0063] Furthermore, the electronic device 100 includes earphones 121 (earphones 121R and 121L). Instead of earphones 121, it may also be equipped with bone conduction acoustic devices 122 (acoustic devices 122R and 122L). Either or both of the earphones 121 and the bone conduction acoustic devices 122 may be provided. For example, the electronic device 100 is equipped with bone conduction acoustic devices 122 on the mounting part 103. Using bone conduction acoustic devices 122, the user can hear the acoustic signals transmitted from the electronic device 100 and ambient sounds simultaneously.

[0064] [Sensor unit] Sensor units 50 and 51 have the function of acquiring one or more of the user's visual, auditory, tactile, gustatory, and olfactory information. More specifically, sensor units 50 and 51 have the function of detecting or measuring one or more of the following: force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, magnetism, temperature, sound, time, electric field, electric current, voltage, power, radiation, humidity, gradient, vibration, odor, and infrared radiation. 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 in the sensor unit 50, for example, the surrounding scenery can be captured. Alternatively, the sensor unit 50 may be a sensor capable of measuring one or more of the following: ambient temperature, humidity, illuminance, and odor.

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

[0067] Furthermore, it is preferable that at least one of the sensor unit 50 and sensor unit 51 has the function of measuring brain waves in addition to the above functions. For example, it may have a mechanism that has multiple electrodes that come into contact with the head and measures brain waves from the weak current flowing through these electrodes. By having the function of measuring brain waves in sensor unit 50 or sensor unit 51, it is possible to display an image or a part of an image wherever the user thinks on the display area. The user does not need to use both hands to operate the electronic device 100, so for example, input operations can be performed with nothing in both hands.

[0068] [Power supply section] The battery 104 has the function of storing the power necessary for the operation of the electronic device 100 and the function of supplying the power necessary for its operation. The voltage generation unit 105 has the function of generating the voltage necessary for the operation of the electronic device 100 and the function of maintaining the voltage at a constant level. The battery 104 can be a primary battery or a secondary battery. For example, a lithium-ion secondary battery can be used as the secondary battery. The battery 104 and the voltage generation unit 105 together can be called the power supply unit.

[0069] Although Figure 1A illustrates a configuration with a battery 104, the electronic device 100 is not limited to this. Alternatively, the electronic device 100 may be configured to receive power directly from an external power source without a battery 104. Furthermore, the electronic device 100 may be equipped with a battery 104 and also have a function for receiving power from an external source.

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

[0071] Furthermore, the control unit 106 has the function of supplying image signals to the display device. The control unit 106 can also perform high-resolution processing (upconversion) or low-resolution processing (downconversion) of image signals. This allows for upconversion of low-resolution image data to match the resolution of the display area (also called the "display unit"), or downconversion of high-resolution image data. Therefore, images with high display quality can be displayed on the display device.

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

[0073] [g section] The communication unit 107 has the function of communicating with other terminals, for example, wirelessly or via a wired connection. In particular, having the function of communicating wirelessly is preferable because it can eliminate the number of components such as cables for connection.

[0074] If the communication unit 107 has the function of communicating wirelessly, the communication unit 107 can communicate via the antenna 108. Furthermore, as a communication protocol or communication technology, communication standards such as LTE (Long Term Evolution) or specifications standardized by IEEE such as Wi-Fi (registered trademark), Bluetooth (registered trademark), or ZigBee (registered trademark) can be used. In addition, it is also possible to use third-generation mobile communication systems (3G), fourth-generation mobile communication systems (4G), or fifth-generation mobile communication systems (5G) as defined by the International Telecommunication Union (ITU).

[0075] The communication unit 107 can connect the electronic device 100 to other devices and perform information input and output via computer networks such as the Internet (which forms the basis of the World Wide Web), intranets, extranets, PANs (Personal Area Networks), LANs (Local Area Networks), CANs (Campus Area Networks), MANs (Metropolitan Area Networks), WANs (Wide Area Networks), or GANs (Global Area Networks), for example.

[0076] Furthermore, Figure 1A shows an example in which the electronic device 100 has one antenna 108, but it is not limited to this and may have multiple antennas. By having multiple antennas, the stability of wireless communication can be improved.

[0077] Furthermore, the communication unit 107 may be electrically connected to an external port (not shown) provided on the electronic device 100. The external port may be configured to allow connection to external devices such as computers and printers via cables. Typical examples include USB terminals. The external port may also include, for example, a terminal for LAN (Local Area Network) connection, a terminal for receiving digital broadcasts, or a terminal for connecting an AC adapter. In addition to wired connections, the device may also be configured to include transceivers for optical communication using, for example, infrared, visible light, or ultraviolet light. Furthermore, the communication unit 107 may be electrically connected to, for example, one or more buttons or switches (also called "housing switches," not shown) provided on the electronic device 100.

[0078] [Optical device] This section describes an example of the internal configuration of the housing 101 of the electronic device 100. Figure 1B is a schematic diagram of the inside of the housing 101 as viewed from above.

[0079] The electronic device 100 includes, inside the 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 area 60R and a sensor area 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 area 60L and a sensor area 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 provided separately inside the housing 101, but this is not limited to this. For example, the display device may be partially used for the right eye and partially used for the left eye. Also, for example, the light source may be shared between the right and left eyes. Also, for example, the optical system may be partially shared between the right and left eyes. Thus, there are cases where it is difficult to separate the right and left eye devices. Furthermore, the same configuration may be used for the display device, light source, and optical system for both the right and left eyes.

[0081] Furthermore, since the electronic device 100 is configured to prevent external light from entering the housing 101, the user can experience a high level of immersion. In addition, the electronic device 100 is equipped with a sensor unit 50 at the front of the housing 101, and the sensor unit 50 may use an image sensor to capture the surrounding scenery and display it on one or both of the display devices 10R and 10L. The electronic device 100 can also overlay other information 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] <Example of optical device configuration> An example configuration of the optical device 13 will be described. Figure 2 is a schematic diagram of the optical device 13 viewed from the side. The optical device 13 comprises a display device 10, a light source 11, an optical system 12, and a housing 14. Figure 2 also shows the eyeballs 20 of the user of the electronic device 100. The optical device 13 can be applied to the optical device 13R for the right eye and the optical device 13L for the left eye, respectively, which are provided in the electronic device 100.

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

[0084] Furthermore, the housing 14 only needs to have the function of shielding light from areas other than the openings 14a and 14b, and is not limited to the shape of a frustocone as shown in Figure 2. The housing 14 can be made into an appropriate shape to match the display device 10 and the optical system 12. For example, it may be a frustocone, a frustoconical pyramid, a cylinder, a rectangular prism, or a combination of these shapes.

[0085] Figure 3 is a schematic diagram illustrating an example configuration of the optical system 12. Figure 3 also shows the eyeball 20 of a user of the electronic device 100.

[0086] [light source] The light source 11 has the function of emitting light 32 to illuminate the eyeball 20. It is preferable that the light 32 is not visible light. Furthermore, it is preferable that the light 32 includes infrared light. In other words, it is preferable that the light source 11 has the function of emitting infrared light. Specifically, it has the function of emitting light with a wavelength of 780 nm to 3000 nm, preferably 780 nm to 2500 nm. Light of such wavelengths is preferable because it is not visible to the user and therefore does not interfere with the visibility of the image displayed on the display device. Note that light with a wavelength of 780 nm to 3000 nm is sometimes referred to as infrared light, and light with a wavelength of 780 nm to 2500 nm is sometimes referred to as near-infrared light. While it is often stated that the light source 11 emits infrared light, it may also emit near-infrared light; for example, when detecting gaze, a wavelength of 830 nm to 870 nm is preferable. As the light source 11, for example, a light-emitting diode (sometimes referred to as an LED) can be used.

[0087] [Display device] The display device 10 comprises a display area 60 and a sensor area 52. When the display device 10 and the housing 14 are stacked, the display area 60 and the sensor area 52 are positioned such that a portion or all of each is included in the opening on the display device 10 side of the housing 14 (corresponding to the opening 14a in Figure 2). Furthermore, it is preferable that the sensor area 52 is positioned below the display area 60 when the user views the display device 10 through the optical system 12.

[0088] The display area 60 has the function of displaying an image. Specifically, the display area 60 has a light-emitting element, and the image is represented by the light 31 emitted by the light-emitting element. Therefore, the light 31 emitted from the display area 60 includes visible light. The light 31 is shone onto the eyeball 20 via the optical system 12. As a result, the user can view the image.

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

[0090] Furthermore, the object imaged in the sensor area 52 is not limited to the eyeball 20; for example, a wider area than the eyeball 20 may be imaged, including the user's eyeball or eyelids. In addition, the sensor area 52 may be used to measure, for example, the number of blinks, eyelid movement, changes in pupil size, or gaze movement, in order to detect, for example, the user's fatigue level and health condition. Moreover, by appropriately combining this information with the information obtained from the aforementioned sensor unit 51, the detection accuracy can be improved.

[0091] Furthermore, by detecting the user's gaze, it is possible to determine where the user is focusing their attention. For example, by combining the detection of the area of ​​focus with the measurement of the number of blinks per unit time, it becomes possible to select an icon displayed in the display area of ​​the display device 10. In other words, by detecting the user's gaze and eyelid movements, it is possible to perform an action of clicking an icon with a mouse. That is, by detecting the user's gaze and eyelid movements, the operation of the electronic device 100 can be controlled. Since the user does not need to use both hands to operate the electronic device 100, for example, input operations can be performed with nothing in both hands.

[0092] The sensor area 52 may be provided separately from the display area 60, or it may be provided overlapping with the display area 60. For example, as shown in Figure 4A, by providing the sensor area 52 and the display area 60 separately, the influence of light emitted from the display area 60 on the sensor area 52 can be reduced. Alternatively, as shown in Figure 4B, by providing the sensor area 52 and the display area 60 overlapping, the sensor area 52 can function as the display area 60 when not detecting light 33, thereby providing a wider display area for the image.

[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 to appropriately control the optical path so that light 31 emitted from the display area 60 in the display device 10 enters the eyeball 20. It also has a function to appropriately control the optical path so that light 33 reflected by the eyeball 20 enters the sensor area 52 in the display device 10.

[0095] The optical system 12 comprises one or more optical elements. These optical elements can be, for example, one or more selected from lenses, prisms, mirrors, filters, and diffraction gratings.

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

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

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

[0099] It should be noted that the optical system that can be used in the optical device according to one aspect of the present invention is not limited to the configuration example shown in Figure 3. Figure 3 shows an example in which plane mirrors are used as mirrors 21 and 22, but it is not limited to this, and for example, concave mirrors and convex mirrors may be used. Also, for lens 23, for example, spherical lenses, aspherical lenses and Fresnel lenses can be used. By appropriately selecting these, the optical path can be appropriately controlled so that light 31 emitted from the display area 60 is imaged at the eyeball 20, and light 33 reflected at the eyeball 20 is imaged at the sensor area 52.

[0100] Furthermore, in order to appropriately control the optical paths of light 31 and light 33, one or more optical elements can be used in appropriate combinations. For example, as another example of the configuration of the optical system 12, as shown in Figure 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, Figure 6 shows a schematic diagram in which a lens 25 is provided on the sensor area 52 of the display device 10. As the lens 25, for example, a microlens and a pinhole may be provided on the sensor area 52.

[0101] <Variations in the configuration of an optical device> The configuration of the optical device 13 is not limited to the example shown in Figure 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 out visible light between the light source 11 and the eyeball 20, even if the light 32 emitted by the light source 11 contains a visible light component, only infrared light can be irradiated onto the eyeball 20. This improves the visibility of the image. Alternatively, by providing a lens 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. This allows for the acquisition of clearer imaging data when imaging the eyeball 20 with the sensor area 52.

[0102] Furthermore, the location of the light source 11 is not limited to the area around the opening 14b of the housing 14. For example, the light source 11 may be provided on the display device 10. In addition, a light-emitting element (for example, an organic electroluminescent element) that has the function of emitting infrared light may be used as the light source 11, rather than an LED.

[0103] For example, as shown in Figures 7 and 8, a light source 11 may be provided around the display area 60 and the sensor area 52 of the display device 10. Figure 8A is a schematic diagram showing the case where the sensor area 52 and the display area 60 are separated, and Figure 8B is a schematic diagram showing the case where the sensor area 52 is located within the display area 60. By providing the light source 11 in the display device 10, the electronic device 100 can be made more compact and lighter.

[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] <Example of peripheral circuit configuration for display area and sensor area> An example configuration of the display device 10 will be described. Figure 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 peripheral circuit area 232 function, for example, as scan line driving circuits for the display area 60. The circuits included in peripheral circuit area 233 function, for example, as signal line driving circuits for the display area 60. The circuits included in peripheral circuit area 292 function, for example, as row signal line driving circuits for the sensor area 52. The circuits included in peripheral circuit area 293 function, for example, as readout circuits for the sensor area 52. Note that the circuits included in peripheral circuit areas 232, 233, 292, and 293 are sometimes collectively referred to as "peripheral driving circuits."

[0107] Various types of peripheral drive circuits can be used, such as shift registers, level shifters, inverters, latches, analog switches, logic circuits, source followers, operational amplifiers, or amplification circuits. Transistors or capacitive elements can also be used in the peripheral drive circuits. The transistors in the peripheral drive circuits can be formed using the same process as the transistors included in pixels 230 and 290.

[0108] Furthermore, the display device 10 has m (m is an integer of 1 or more) wires 236, each arranged substantially parallel to the others and whose potential is controlled by circuits included in the peripheral circuit region 232, and n (n is an integer of 1 or more) wires 237, each arranged substantially parallel to the others and whose potential is controlled by circuits included in the peripheral circuit region 233. Furthermore, the display device 10 has p (p is an integer of 1 or more) wires 296, each arranged substantially parallel to the others and whose potential is controlled by circuits included in the peripheral circuit region 292, and q (q is an integer of 1 or more) wires 297, each arranged substantially parallel to the others and whose potential is controlled by circuits included in the peripheral circuit region 293.

[0109] The display area 60 has a plurality of pixels 230 arranged in a matrix. Furthermore, 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 combined and function as a single pixel, and full-color display can be achieved by controlling the amount of light emitted (luminance) of each pixel 230. Thus, each of these three pixels 230 functions as a sub-pixel. That is, each of the three sub-pixels controls the amount of red light, green light, or blue light emitted. Note that the color of light controlled by each of the three sub-pixels 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] Alternatively, the four subpixels may be combined and function as a single pixel. For example, a subpixel controlling the emission amount of white light may be added to the three subpixels that control the emission amounts of red, green, and blue light, respectively. By adding a subpixel that controls the emission amount of white light, the brightness of the display area can be increased. Alternatively, a subpixel that controls the emission amount of yellow light may be added to the three subpixels that control the emission amounts of red, green, and blue light, respectively. Alternatively, a subpixel that controls the emission amount of white light may be added to the three subpixels that control the emission amounts of cyan, magenta, and yellow light, respectively.

[0111] By increasing the number of subpixels that function as a single pixel, and by appropriately combining subpixels that control the amount of light emitted, such as red, green, blue, cyan, magenta, and yellow, the reproduction of midtones can be improved. Therefore, the display quality can be enhanced.

[0112] Furthermore, a display device according to one aspect of the present invention can reproduce a variety of color gamuts. For example, it can reproduce color gamuts such as the PAL (Phase Alternating Line) standard and NTSC (National Television System Committee) standard used in television broadcasting, the sRGB (standard RGB) standard and Adobe RGB standard widely used in display devices for electronic devices such as personal computers, digital cameras, and printers, the ITU-R BT.709 (International Telecommunication Union Radiocommunication Sector Broadcasting Service (Television) 709) standard used in HDTV (High Definition Television), the DCI-P3 (Digital Cinema Initiatives P3) standard used in digital cinema projection, or the ITU-R BT.2020 (REC.2020 (Recommendation 2020)) standard used in UHDTV (Ultra High Definition Television).

[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). In particular, a resolution of 4K2K, 8K4K, or higher is preferred.

[0114] Furthermore, the pixel density (resolution) of the display area 60 is preferably 1000 ppi or more and 10000 ppi or less. For example, it may be 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 aspect ratio of the display area 60. The display area 60 of the display device 10 can support various aspect ratios, such as 1:1 (square), 4:3, 16:9, or 16:10.

[0116] Furthermore, a display device according to one aspect of the present invention can have a variable refresh rate. For example, power consumption can be reduced by adjusting the refresh rate according to the content displayed on the display device (for example, adjusting within a range of 0.01 Hz to 240 Hz). In addition, a drive that reduces the power consumption of the display device by driving with a reduced refresh rate may be called an idling stop (IDS) drive.

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

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

[0119] Furthermore, the sensor area 52 can be provided within the display area 60 (see Figure 4B). That is, for example, pixel 290 and three pixels 230 can each be treated as sub-pixels, and the four sub-pixels can be grouped together as one pixel. In the display area 60, the three pixels 230 can be made functional to achieve full-color display. In addition, in the sensor area 52, pixel 290 can be made functional to realize the function of outputting a signal according to the amount of light received.

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

[0121] <Example of pixel circuit configuration> Figure 10A shows an example of the circuit configuration of a pixel 230 in the display area 60. The pixel 230 has a pixel circuit 431 and a light-emitting element 432.

[0122] Each wire 236 is electrically connected to n pixel circuits 431 located in any row of the m rows and n columns of the display area 60. Similarly, each wire 237 is electrically connected to m pixel circuits 431 located in any column of the m rows and n columns of the pixel circuits 431. m and n are both integers greater than or equal to 1.

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

[0124] In this specification and other documents, the term "element" may sometimes be replaced with "device." For example, display elements, light-emitting elements, and liquid crystal elements can be replaced with display devices, light-emitting devices, and liquid crystal devices.

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

[0126] Transistor 436 has the function of controlling the writing of data signals to wiring 435.

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

[0128] Capacity 433 functions as a holding capacity for data written to wiring 435.

[0129] One of the sources or drains of transistor 438 is electrically connected to the potential supply line VL_a, and the other is electrically connected to wiring 437. Furthermore, the gate of transistor 438 is electrically connected to wiring 435.

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

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

[0132] For example, an organic electroluminescent element (also called 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 inorganic material may be used. Note that "organic EL elements" and "inorganic EL elements" are sometimes collectively referred to as "EL elements".

[0133] The light-emitting color of an EL element can be, for example, white, red, green, blue, cyan, magenta, or yellow, depending on the materials that make up the EL element.

[0134] There are two methods for achieving color display: one involves combining a white-emitting light-emitting element 432 with a colored layer, and the other involves providing a different-colored light-emitting element 432 for each pixel. The former method is more productive than the latter. On the other hand, the latter method is less productive than the former because it requires the creation of a different light-emitting element 432 for each pixel. However, the latter method can produce a more color-pure emitted color than the former method. In addition to the latter method, the color purity can be further improved by adding a microcavity structure to the light-emitting element 432.

[0135] The light-emitting element 432 may be made of either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. Each layer constituting the light-emitting element 432 can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, or coating.

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

[0137] Furthermore, as the power supply potential, for example, the power supply potential on the relatively higher potential side or the power supply potential on the lower potential side can be used. The power supply potential on the higher potential side can be called the high power supply potential VDD1, and the power supply potential on the lower potential side can be called the low power supply potential VSS1. For example, the high power supply potential VDD1 is supplied to one of the potential supply lines VL_a or VL_b, and the low power supply potential VSS1 is supplied to the other.

[0138] Furthermore, for example, the ground potential can be used as either the high power potential or the low power potential. For instance, if the high power potential is the ground potential, the low power potential is lower than the ground potential, and if the low power potential is the ground potential, the high power potential is higher than the ground potential.

[0139] The display device having pixel circuits 431 sequentially selects each row of pixel circuits 431 using a circuit included in the peripheral drive circuit, turns on transistors 436 and 434, and writes a data signal to wiring 435.

[0140] When data is written to wiring 435, the pixel circuit 431 enters a holding state when transistors 436 and 434 are turned off. Furthermore, the amount of current flowing between the source and drain of transistor 438 is controlled according to the potential of the data written to wiring 435, and the light-emitting element 432 emits light with a brightness corresponding to the amount of current flowing. By performing this sequentially for each row, an image can be displayed.

[0141] Figure 10B shows an example of the circuit configuration of a pixel 290 in the sensor region 52. The pixel 290 has a pixel circuit 491 and a light-receiving element 492.

[0142] Each wire 296 is electrically connected to q pixel circuits 491 located in any row of the pixel circuits 491 arranged in p rows and q columns in the sensor area 52. Similarly, each wire 297 is electrically connected to p pixel circuits 491 located in any column of the pixel circuits 491 arranged in p rows and q columns. p and q are both integers greater than or equal to 1.

[0143] The pixel circuit 491 includes transistors 496, 493, 498, and 494. The pixel circuit 491 is also electrically connected to the photodetector 492.

[0144] In this specification and other documents, the term "element" may sometimes be replaced with "device." For example, a photodetector element can be replaced with a photodetector device.

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

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

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

[0148] One of the sources or drains of transistor 498 is electrically connected to the potential supply line VL_e, and the other is connected to wiring 497. Furthermore, the gate of transistor 498 is electrically connected to wiring 495.

[0149] One of the sources or drains of transistor 494 is electrically connected to the wiring that reads the detection signal (hereinafter referred to as signal line WX_q), and the other is connected to wiring 497. Furthermore, the gate of transistor 494 is electrically connected to the wiring to which the third row selection signal is supplied (hereinafter referred to as row selection line SE_p).

[0150] Note that the row selection lines TX_p, RS_p, and SE_p correspond to wiring 296. Also, the signal line WX_q corresponds to wiring 297.

[0151] One of the anodes or cathodes of the photodetector 492 is electrically connected to the potential supply line VL_d, and the other is electrically connected to the wiring 499.

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

[0153] Furthermore, the power supply potential can be, for example, a power supply potential on the relatively higher or lower side. The power supply potential on the higher side can be called the high power supply potential VDD2, and the power supply potential on the lower side can be called the low power supply potential VSS2. Also, a power supply potential that is relatively higher than the high power supply potential VDD2 can be called the high power supply potential VDD3. For example, one of the potential supply lines VL_c or VL_d is supplied with the high power supply potential VDD2, and the other is supplied with the low power supply potential VSS2. Also, for example, the potential supply line VL_e is supplied with the high power supply potential VDD3.

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

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

[0156] When imaging is performed, first, transistors 493 and 496 are turned on to supply the potential applied to the potential supply line VL_c to wiring 499 (also called initialization). Next, by turning off transistors 493 and 496, a charge corresponding to the amount of light received by the photodetector 492 is gradually accumulated in wiring 499 (also called exposure). Then, after a set time (exposure time) has elapsed, transistor 496 is turned on to transfer the charge accumulated in wiring 499 to wiring 495 (also called transfer). As a result, the potential of wiring 495 becomes a value corresponding to the amount of light received by the photodetector 492. Finally, imaging is completed by turning off transistor 496.

[0157] When reading out data, turning on transistor 494 causes a current to flow through the signal line WX_q, corresponding to the potential of wiring 495. In other words, a current flows through the signal corresponding to the amount of light received by photodetector 492. This current is detected by the circuitry included in the peripheral circuit region 293. By performing this for each row, the captured signal can be read out.

[0158] Furthermore, some or all of the transistors constituting the pixel circuit 431 and the pixel circuit 491 may be transistors having back gates. For example, some or all of the transistors constituting the pixel circuit 431 and the pixel circuit 491 may be transistors having back gates, and the back gate and the gate may be electrically connected. Alternatively, some or all of the transistors constituting the pixel circuit 431 and the pixel circuit 491 may be transistors having back gates, and the back gate and either the source or the drain of the transistor may be electrically connected.

[0159] <Specific example of display device configuration> Figure 11 is a block diagram showing an example configuration 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 may have one or more functional circuits for each element that realizes a function. In Figure 11, an example of a functional circuit provided in the functional circuit area 234 is shown: a control unit 130, an arithmetic unit 140, a memory unit 150, an input / output unit 160, and a gaze detection unit 170. The control unit 130, arithmetic unit 140, memory unit 150, input / output unit 160, and gaze detection unit 170 are each electrically connected via a bus line 131.

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

[0161] [Calculation section] The arithmetic unit 140 has the function of performing calculations related to the overall operation of the display device 10, and can use, for example, a central processing unit (CPU). The arithmetic unit 140 also has the function of generating images to be displayed in the display area 60.

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

[0163] Furthermore, the processing unit 140 includes a neural network 141. The neural network 141 may be configured in software. One or more of the following can be used as the neural network 141: deep neural networks, convolutional neural networks, recurrent neural networks, autoencoders, deep Boltzmann machines, and deep belief networks.

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

[0165] The arithmetic unit 140 may have main memory. The main memory may include volatile memory such as RAM (Random Access Memory) or non-volatile memory such as ROM (Read Only Memory).

[0166] For example, DRAM (Dynamic Random Access Memory) is used as the RAM provided in the main memory, and a virtual memory space is allocated and used as the workspace for the arithmetic unit 140. For example, the operating system, application programs, program modules, or program data stored in the storage unit 150 are loaded into RAM for execution. These data, programs, and program modules loaded into RAM are directly accessed and manipulated by the arithmetic unit 140.

[0167] On the other hand, ROM can store data that does not require rewriting, such as BIOS (Basic Input / Output System) and firmware. Examples of ROMs that can be used include mask ROM, OTPROM (One Time Programmable Read Only Memory), or EPROM (Erasable Programmable Read Only Memory). Examples of EPROMs include UV-EPROM (Ultra-Violet Erasable Programmable Read Only Memory), which allows data to be erased by ultraviolet irradiation, EEPROM (Electrically Erasable Programmable Read Only Memory), or flash memory.

[0168] [Storage section] The memory unit 150 may be a memory device using non-volatile memory elements such as flash memory, MRAM (Magnetoresistive Random Access Memory), PRAM (Phase Change RAM), ReRAM (Resistive RAM), or FeRAM (Ferroelectric RAM), or a memory device using volatile memory elements such as DRAM (Dynamic RAM) or SRAM (Static RAM).

[0169] The memory unit 150 stores, for example, multiple algorithms for upconverting image data, and weight coefficients for each algorithm. The memory unit 150 may also store image sources to be displayed in the display area 60.

[0170] [Input / output section] The input / output unit 160 is electrically connected to the control unit 106 of the electronic device 100. The input / output unit 160 may also 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 called "enclosure switches") provided on the electronic device 100. It may also be electrically connected to an external port to which other input components can be connected.

[0171] In this embodiment, the display device 10 is shown as having a functional circuit area 234, but it is not limited to this. Some or all of the functional circuits of the functional circuit area 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 that case, the storage unit 150 is electrically connected to the functional circuits of the display device 10 (for example, the arithmetic unit 140, etc.) via the input / output unit 160. Alternatively, a communication means may be provided to exchange data wirelessly.

[0172] [Eye-tracking unit] The gaze detection unit 170 has the function of detecting the user's gaze using information obtained from the sensor area 52. The user's gaze can be detected using known eye-tracking methods. For example, it can be detected by the Pupil Centre Corneal Reflection (PCCR) method or the Bright / Dark Pupil Effect method.

[0173] For example, the PCCR method is a method of detecting a user's gaze from the relative position of the corneal reflection image (Purkinje image) produced when light is shone on the eyeball, with respect to the center position of the user's pupil. When detecting a user's gaze using the PCCR method, the user's pupil and Purkinje image are captured using the sensor area 52, and the gaze detection unit 170 can detect the user's gaze. 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 only needs to have the function of detecting one or more of the user's cornea, iris, lens, and retina.

[0174] <An 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, based on the user's gaze information detected by the gaze detection unit 170, identify an area in the display area 60 that overlaps with the gaze and perform image processing according to the position of the gaze.

[0175] An example of image processing that responds to the user's gaze will be described. Figure 12A shows the user's gaze point G and a first region S1 containing the gaze point G, superimposed on the image displayed in the display area 60. Furthermore, a second region S2 is shown outside the first region S1, and a third region S3 is shown outside the second region S2, superimposed on the image in the display area 60.

[0176] Human vision, although varying from person to person, can be classified into the discriminative field of view, effective field of view, stable gaze field of view, guided field of view, and auxiliary field of view. The discriminative field of view is the area where visual function, such as visual acuity or color discrimination, is best. Considering the intersection line between the user and the display area 60, the discriminative field of view refers to the area within a horizontal angle θx1 = approximately 5° centered on the intersection line (see Figure 12B for angle θx1). In other words, the discriminative field of view corresponds to the first area S1 in Figure 12A.

[0177] The effective field of view is the area in which specific information can be instantly identified solely by eye movements. It is defined as the area within a horizontal angle θx2 = approximately 30° centered on the intersection line, and, although not shown in Figure 12B, within a vertical angle of approximately 20° (see Figure 12B for angle θx2). In other words, the effective field of view corresponds to the second region S2 in Figure 12A.

[0178] The stable field of view is the area in which specific information can be identified without strain while moving the head. The guided field of view is the area in which the presence of a specific object can be recognized, but the ability to identify it is low. The auxiliary field of view is the area in which the ability to identify a specific object is extremely low, and only the presence of a stimulus can be recognized. One or more fields of view selected from the stable field of view, guided field of view, and auxiliary field of view correspond to the third region S3 in Figure 12A.

[0179] From the above, it is clear that image quality from the discrimination field to the effective field of view is important in video. In particular, it is crucial to improve the image quality of the discrimination field. Therefore, it is advisable to perform image processing using the control unit 130 to improve the image quality of the first region S1, or the first region S1 and the second region S2, as shown in Figure 12A. That is, it is advisable 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 video by upconversion.

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

[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, sensor unit 51, and sensor area 52, and information obtained by the image processing described above. The image data is sent to the peripheral circuit area 293 via the bus line 131 and displayed in the display area 60.

[0182] <Examples of electronic device operation> An example of the operation of an electronic device according to one aspect of the present invention will be described below using the flowchart shown in Figure 13.

[0183] The flowchart shown in Figure 13 has steps S210 to S213. First, in step S210, infrared light 31 is emitted from the light source 11 to illuminate the user's eyeball 20. Next, in step S211, the light 33 reflected from the eyeball 20 is captured by the sensor area 52. Furthermore, in step S212, the captured data acquired by the sensor area 52 is read out by the peripheral circuit area 293, and the gaze detection unit 170 detects the user's gaze using this captured data. Then, in step S213, the point of focus G on the display area 60 is determined based on the user's gaze. Subsequently, in step S214, the image to be displayed is updated to match the user's gaze.

[0184] For example, as shown in Figure 12, image processing to increase the resolution can be performed in the first region S1. By processing to increase the resolution only in that region, the load on the GPU of the arithmetic unit 140 can be reduced, for example.

[0185] Furthermore, it can detect the user's gaze. By detecting the user's gaze, 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 reproduce the user's eye movements on an avatar. In addition, it is possible to perform operations or menu selections using gaze.

[0186] 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 herein, etc., at least in part.

[0187] (Embodiment 2) This embodiment describes an example of the configuration of a display device according to one aspect of the present invention.

[0188] [Example of a display device configuration] Using the display device 180 shown in Figures 14A and 14B as an example, an example of the configuration of a display device in an electronic device according to one aspect of the present invention will be explained.

[0189] The display device 180 shown in Figure 14A comprises 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)) as display elements and a light-emitting element (190(IR)) as an infrared light source, and is located on 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 element 190 can be configured to include, for example, a red-emitting element 190(R), a green-emitting element 190(G), a blue-emitting element 190(B), and an infrared-emitting element 190(IR). In this configuration, 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; there may be one or multiple. The light-emitting element 190 is placed in the region sandwiched between substrate 181 and substrate 182. Substrate 181 is placed between the support plate 183 and the light-emitting element 190, and substrate 182 is placed 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, and more preferably near-infrared light. For example, infrared light with a wavelength of 700 nm or more, and 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 the function of detecting infrared light. Preferably, the light-receiving element has a light sensitivity that corresponds to infrared light, preferably near-infrared light emission, emitted by the light-emitting element 190 (IR).

[0193] As shown in Figure 14A, an image is displayed by the light emitted from the light-emitting elements 190(R), 190(G), and 190(B). In addition, infrared light emitted from the light-emitting element 190(IR) is reflected by the user's eyeball 188, and gaze detection is performed when this reflected light is detected by the light-receiving element of the light-receiving element 191. For this reason, the substrate 182 and the protective member 185 need to transmit both the visible light from the light-emitting elements 190(R), 190(G), and 190(B), and the infrared light reflected by the light-emitting element 190(IR) and the eyeball 188. Therefore, it is preferable that the substrate 182 and the protective member 185 are translucent to both visible light and infrared light. Furthermore, the infrared light reflected by the eyeball 188 needs to pass through the substrate 181. Therefore, it is preferable that the substrate 181 is translucent to at least infrared light.

[0194] Substrates 181 and 182 can be made of various materials, such as an insulator like glass, quartz, ceramics, sapphire, or stabilized zirconia (e.g., yttria-stabilized zirconia), a resin like an insulating resin or conductive resin, a semiconductor like silicon, germanium, silicon carbide, silicon germanium, gallium arsenide, indium phosphide, or zinc oxide, a metal, or an alloy. The substrate on the side that extracts light from the light-emitting element 190 should be made of a material that transmits light. Using flexible materials for substrates 181 and 182 can increase the flexibility of the display device 180 and enable weight reduction and thinning. Polarizing plates may also be used as substrate 181 or substrate 182.

[0195] Substrates 181 and 182 may be, for example, polyester resins 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, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, or cellulose nanofiber, etc. One or both of substrates 181 and 182 may be made of glass of a thickness sufficient to provide flexibility.

[0196] Furthermore, one aspect of the present invention may be configured as shown in Figure 14B. The display device shown in Figure 14B differs from the display device shown in Figure 14A in that the light-emitting element 190 (IR), which serves as an infrared light source, is provided within the pixel section 189. The other configurations are the same as those of the display device shown in Figure 14A, so for details, please refer to the description of Figure 14A above.

[0197] As described above, in the display device 180 shown in Figures 14A and 14B, the layer 186 on which the light-emitting element 190 (IR) is located is superimposed on the light-receiving element 191. In the layer 186 on 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 reflected light from the eyeball 188 can be received without using a complex optical system. In addition, the distance between the light-emitting element 190 (IR) and the light-receiving element 191 becomes relatively small. Therefore, the detection sensitivity of reflected light from the eyeball 188 can be increased. Furthermore, since the configuration of the optical system 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] It should be noted that the present invention is not limited to this embodiment, and as shown in Figures 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 shown in Figure 15A differs from the display device 180 shown in Figure 14A in that the light-receiving element 191 and the light-emitting element 190 are provided between the substrate 181 and the substrate 182. Similarly, the display device 180 shown in Figure 15B differs from the display device 180 shown in Figure 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 the display devices 180 shown in Figures 15A and 15B, since the light-receiving element 191 is provided on the substrate 181, the substrate 181 may have low light transmittance to infrared light, or may not have light transmittance to infrared light at all.

[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 Figure 16A, the light-receiving element 191 is also provided outside the pixel portion 189 together with the light-emitting element 190(IR). In the display device 180 shown in Figure 16B, only the light-receiving element 191 is provided outside the pixel portion 189. In the display device 180 shown in Figure 17A, the light-receiving element 191 is also provided outside the pixel portion 189 together with the light-emitting element 190(IR). In the display device 180 shown in Figure 17B, only the light-receiving element 191 is provided outside the pixel portion 189.

[0200] Furthermore, while the above describes a configuration in which pixels are formed using four types of light-emitting elements: a red-emitting element 190(R), a green-emitting element 190(G), a blue-emitting element 190(B), and an infrared-emitting element 190(IR), the present invention is not limited to this. For example, the light-emitting element 190(R) may be configured to emit light with peaks at both red and infrared wavelengths, and the pixels may be formed using three types of light-emitting elements: light-emitting element 190(R), light-emitting element 190(G), and light-emitting element 190(B).

[0201] In addition, in the display devices 180 shown in Figures 15A, 15B, 17A, and 17B, it may not be necessary to provide the support plate 183.

[0202] Furthermore, in the display devices 180 shown in Figures 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. It is preferable that the insulating layer is transparent to at least infrared light.

[0203] Furthermore, in each of the display devices 180 described above, it may not be necessary to provide the protective member 185.

[0204] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0205] (Embodiment 3) This embodiment describes a schematic top view of the light-emitting element and its surroundings in the display device, a schematic cross-sectional view thereof, an example of the configuration of the light-emitting element, an example of the configuration of the light-emitting element and light-receiving element, and an example of the configuration of the display device.

[0206] <Schematic top view of the light-emitting element and its surroundings, and schematic cross-sectional view thereof> Figure 18A is a schematic top view showing an example configuration of a display device 70 according to one aspect of the present invention, in which a light-emitting element and a light-receiving element are arranged within a single pixel. The display device 70 has multiple red light-emitting elements 61R, green light-emitting elements 61G, blue light-emitting elements 61B, infrared light-emitting elements 61IR, and light-receiving elements 62.

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

[0208] In Figure 18A, to simplify the distinction between each light-emitting element 61, the symbols R, G, B, or IR are added within the light-emitting region of each light-emitting element 61. Additionally, the symbol PD is added within the light-receiving region of each photodetector 62.

[0209] The light-emitting elements 61R, 61G, 61B, 61IR, and light-receiving elements 62 are each arranged in a matrix. Figure 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. Figure 18A also shows an example configuration in which 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 Figure 18A, for example, a pixel 80 can be composed of sub-pixels having light-emitting elements 61R, sub-pixels having light-emitting elements 61G, sub-pixels having light-emitting elements 61B, and sub-pixels having light-emitting elements 61IR arranged in the X direction, and sub-pixels having light-receiving elements 62 provided below these sub-pixels. The light-receiving elements 62 have the function of detecting infrared light.

[0210] Figure 18A shows a so-called stripe array, in which light-emitting elements that emit light of the same color in one direction are arranged. However, the arrangement method of the light-emitting elements is not limited to this; other arrangement methods such as delta arrays and zigzag arrays may also be applied, and pentile arrays can also be used.

[0211] It is preferable to use EL elements such as OLED (Organic Light Emitting Diode) or QLED (Quantum-dot Light Emitting Diode) as the light-emitting elements 61R, 61G, 61B, and 61IR. The light-emitting material of the light-emitting element may be, for example, a fluorescent material, a phosphorescent material, an inorganic compound (e.g., a quantum dot material), or a thermally activated delayed fluorescence material. Examples include 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 it and generates an electric charge. In the light-receiving element 62, the amount of charge generated is determined based on the amount of incident light.

[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 thinner, lighter, and larger in area, and because they offer a high degree of freedom in shape and design, they can be applied to various display devices.

[0214] In one aspect 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, an organic photodiode can be incorporated into a display device using an organic EL element.

[0215] Incidentally, when creating different light-emitting layers between light-emitting elements exhibiting two different colors, a method is known to form them using a vapor deposition method with a shadow mask such as a metal mask or FMM (Fine Metal Mask, high-resolution metal mask). In this specification, such elements may be referred to as MM (metal mask) structure elements. However, with MM structure elements, deviations from the design occur in the shape and position of island-like organic films due to various influences such as the precision of the metal mask, the misalignment between the metal mask and the substrate, the deflection of the metal mask, and the spread of the contour of the deposited film due to vapor scattering, for example, making it difficult to achieve high resolution and high aperture ratio. For this reason, measures have been taken to artificially increase resolution (also called pixel density) by applying special pixel arrangement methods such as pentile arrangements.

[0216] For example, the light-emitting layer is processed into a fine pattern without using a metal mask or a shadow mask such as an FMM. Specifically, the light-emitting layer is processed into a fine pattern using photolithography. In this specification, elements formed in this manner may be referred to as MML (metal maskless) structure elements. By using MML structure elements, it is possible to realize display devices with high resolution and a large aperture ratio, which were previously difficult to achieve. Furthermore, because the light-emitting layer can be differentiated, it is possible to realize display devices that are extremely vivid, have high contrast, and high display quality.

[0217] Here, for simplicity, we will describe the case where two different colored light-emitting layers of a light-emitting element are created. First, a first light-emitting film and a first sacrificial film are laminated and formed covering the two pixel electrodes. Next, a resist mask is formed on the first sacrificial film at a position overlapping one of the pixel electrodes (the first pixel electrode). Then, the resist mask, a part of the first sacrificial film, and a part of the first light-emitting film are etched. At this point, the etching is stopped when the other pixel electrode (the second pixel electrode) is exposed. As a result, a strip-shaped or island-shaped portion of the first light-emitting film (also called the first light-emitting layer) and a part of the sacrificial film (also called the first sacrificial layer) can be formed on the first pixel electrode.

[0218] Next, the second light-emitting film and the second sacrificial film are laminated together. Then, a resist mask is formed at the position overlapping with the first pixel electrode and the position overlapping with 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, the first light-emitting layer and the first sacrificial layer are provided on the first pixel electrode, and the second light-emitting layer and the second sacrificial layer are provided on the second pixel electrode. In this way, the first light-emitting layer and the second light-emitting layer can be created separately. Finally, the first and second sacrificial layers are removed, exposing the first and second light-emitting layers, and then a common electrode is formed to create two light-emitting elements that emit light of different colors.

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

[0220] Here, in order to supply potential to the common electrode, an electrode (for example, also called a first electrode or connecting electrode) can be provided on the same plane as the pixel electrode and electrically connected to the common electrode. The connecting electrode is positioned outside the display area where the pixels are provided. Here, in order to prevent the upper surface of the connecting electrode from being exposed to etching when the first light-emitting film is etched, it is preferable to provide a first sacrificial layer on the connecting electrode as well. Similarly, when etching the second light-emitting film, it is preferable to provide a second sacrificial layer on the connecting electrode. The first and second sacrificial layers provided on the connecting 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] While it is difficult to reduce the distance between two light-emitting layers exhibiting different colors to less than 10 μm in an MM structure, for example, an MML structure can narrow it to less than 6 μm, less than 4 μm, less than 3 μm, less than 2 μm, or even less than 1 μm. Furthermore, by using exposure equipment designed for LSIs, for example, the gap can be narrowed to less than 500 nm, less than 200 nm, less than 100 nm, and even less than 50 nm. This significantly reduces the area of ​​the non-emitting region that can exist between the two light-emitting elements, making it possible to approach a 100% aperture ratio. For example, an aperture ratio of 50% or more, 60% or more, 70% or more, 80% or more, and even less than 90% can be achieved.

[0222] Furthermore, the pattern of the light-emitting layer itself can be made extremely small compared to when a metal mask is used. Also, for example, when a metal mask is used to create different types of light-emitting layers, variations in thickness occur between the center and edges of the pattern, so the effective area that can be used as a light-emitting region is small relative to the total area of ​​the pattern. On the other hand, in the above manufacturing method, the pattern is formed by processing a film deposited to a uniform thickness, so the thickness can be made uniform within the pattern, and even if the pattern is fine, almost the entire area can be used as a light-emitting region. Therefore, the above manufacturing method can achieve both high resolution and a high aperture ratio.

[0223] Thus, the above manufacturing method makes it possible to realize a display device that integrates fine light-emitting elements. Therefore, there is no need to apply a special pixel arrangement method such as the pentile method to artificially increase the resolution. Thus, it is possible to realize a display device with a resolution of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, 3000 ppi or more, or even 5000 ppi or more, using a so-called stripe arrangement in which R, G, and B are each arranged in one direction.

[0224] Figure 18A shows a common electrode 81 and a connecting electrode 82. Here, the connecting electrode 82 is electrically connected to the common electrode 81. The connecting electrode 82 is located outside the display area where the light-emitting element 61 and the light-receiving element 62 are arranged. Also in Figure 18A, the common electrode 81, which has an overlapping area with the light-emitting element 61, the light-receiving element 62, and the connecting electrode 82, is shown with a dashed line.

[0225] The connecting electrode 82 can be provided along the outer perimeter of the display area. For example, it may be provided along one side of the outer perimeter of the display area, or it may be provided across two or more sides of the outer perimeter of the display area. That is, if the top surface shape of the display area is rectangular, the top surface shape of the connecting electrode 82 can be, for example, a strip, an L-shape, a U-shape (angle bracket shape), or a square.

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

[0227] In the display device 70 shown in Figure 18B, the light-emitting elements 61R, 61G, and 61B are arranged in different rows from the light-emitting element 61IR. Therefore, the width (length in the X direction) of the light-emitting elements 61R, 61G, and 61B can be increased, thereby increasing the brightness of the light emitted by the pixels 80.

[0228] Figure 19A is a schematic top view showing an example configuration of the display device 70, and is a modified version of the display device 70 shown in Figure 18B. The display device 70 shown in Figure 19A differs from the display device 70 shown in Figure 18B in that the light-emitting elements 61 are arranged in the order G, B, R in the X direction, rather than in the order R, G, B. Also, 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, which is another difference from the display device 70 shown in Figure 18B.

[0229] The area occupied by the light-receiving element 62 in the display device 70 shown in Figure 19A is larger than the area occupied by the light-receiving element 62 in the display device 70 shown in Figure 18B. Therefore, the light detection sensitivity of the light-receiving element 62 can be increased. Consequently, for example, if the display device 70 has a gaze detection function, gaze can be detected with high accuracy.

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

[0231] The area occupied by the light-receiving element 62 in the display device 70 shown in Figure 19B is smaller than the area occupied by the light-receiving element 62 in the display device 70 shown in Figure 19A. By reducing the area occupied by the light-receiving element 62, the light-receiving range of each individual light-receiving element 62 can be reduced. This reduces the overlap of light-receiving ranges between different light-receiving elements 62, for example, between adjacent light-receiving elements 62. Therefore, blurring of images captured using the light-receiving element 62, which prevents clear imaging, can be suppressed. For example, if the display device 70 has a gaze detection function, reducing the area occupied by the light-receiving element 62 is preferable because it allows for clearer imaging of the eyeball, etc., and improves the accuracy of authentication.

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

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

[0234] In particular, it is preferable to use a substrate 83 on which a semiconductor circuit including semiconductor elements such as transistors is formed on the semiconductor substrate or insulating substrate. It is preferable that the semiconductor circuit 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, it may also contain, for example, an arithmetic circuit or a memory circuit.

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

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

[0237] In the following, when explaining matters common to pixel electrodes 84R, 84G, 84B, 84IR, and 84PD, the symbols attached to the reference numerals may be omitted, and they may be referred to simply as pixel electrode 84. Similarly, when explaining matters common to hole injection layers 85R, 85G, 85B, and 85IR, the symbols attached to the reference numerals may be omitted, and they may be referred to simply as hole injection layer 85. Similarly, when explaining matters common to hole transport layers 86R, 86G, 86B, 86IR, and 86PD, the symbols attached to the reference numerals may be omitted, and they may be referred to simply as hole transport layer 86. Similarly, when explaining matters common to light-emitting layers 87R, 87G, 87B, and 87IR, the symbols attached to the reference numerals may be omitted, and they may be referred to simply as light-emitting layer 87. Similarly, when explaining matters common to electron transport layers 88R, 88G, 88B, 88IR, and 88PD, the symbols attached to the reference numerals may be omitted, and the explanation may simply refer to it 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 photodetector 62. Therefore, the photodetector 62 may not need to have an electron transport layer 88PD.

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

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

[0241] Furthermore, the light-emitting element 61 and the light-receiving element 62 may have layers other than those shown in Figure 20A, for example, including a hole-blocking layer and an electron-blocking layer. In addition, the light-emitting element 61 and the light-receiving element 62 may have layers containing, for example, a bipolar material (a material with high electron-transport and hole-transport 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 sides 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 in the light-emitting element 61 and the light-receiving element 62.

[0243] The above-mentioned voids are more likely to form when, for example, the distance between the light-emitting layers 87 is shorter. For example, if 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, the above-mentioned voids can be suitably formed.

[0244] For example, Figure 20A shows a configuration in which the light-emitting element 61 is provided with, in order from the bottom layer, 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, in order from the bottom layer, 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. However, the present invention is not limited to this configuration. For example, the light-emitting element 61 may be provided with, in order from the bottom layer, 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, in order from the bottom layer, 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 this common layer can be provided between the hole transport layer of the photodetector 62 and the common electrode. Furthermore, in the light-emitting element 61, the electron injection layer can be separated for each element.

[0245] Furthermore, by using an MML structure for the light-emitting element 61 and the light-receiving element 62, the configurations of the light-emitting element 61 and the light-receiving element 62 can be made different. For example, the light-emitting element 61 may be provided with, in order from the bottom layer, 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 provided with, in order from the bottom layer, 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. With this configuration, the driving voltages of the light-emitting element 61 and the light-receiving element 62 can be made to be in the same direction. In this configuration, a hole injection layer may be provided between the hole transport layer 86PD and the common layer 89 in the light-receiving element 62.

[0246] In the following explanation, we will assume that the electron transport layer is located above the hole transport layer. However, by, for example, substituting "electron" with "hole" and "hole" with "electron," the following explanation can also be applied when the electron transport layer is located below the hole transport layer.

[0247] The hole injection layer is a layer that injects holes from the anode into the hole transport layer, and is a layer containing a material with high hole injection capabilities. Examples of materials with high hole injection capabilities include aromatic amine compounds, or composite materials containing a hole transport material and an acceptor material (electron-accepting 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 containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2 A material having a hole mobility of 1 / Vs or higher is preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport. Preferred hole transport materials include, for example, π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, or furan derivatives), or aromatic amines (compounds having an aromatic amine skeleton), which are materials with high hole transport capabilities.

[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 containing an electron-transporting material. The electron-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having an electron mobility of 1 / Vs or higher are preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes. Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, or metal complexes having a thiazole skeleton, as well as other highly electron-transporting materials such 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, or other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds.

[0250] The electron injection layer is a layer that injects electrons from the cathode into the electron transport layer, and is a layer containing a material with high electron injection property. As the material with high electron injection property, an alkali metal, an alkaline earth metal, or compounds thereof can be used. As the material with high electron injection property, a composite material including an electron transporting material and a donor material (electron donating material) can also be used.

[0251] Examples of materials for the electron injection layer include lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 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, an alkali metal, an alkaline earth metal, or compounds thereof can be used.

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

[0253] Note that it is preferable that the lowest unoccupied molecular orbital (LUMO) level of the organic compound having an unshared electron pair is not less than -3.6 eV and not more than -2.3 eV. In addition, in general, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by CV (cyclic voltammetry), photoelectron spectroscopy, light absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0254] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), or 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds containing lone pairs of electrons. NBPhen has a higher glass transition temperature (Tg) and superior heat resistance compared to BPhen.

[0255] The luminescent layer is a layer containing a luminescent material. The luminescent layer may contain one or more types of luminescent materials. As the luminescent material, for example, a material that emits light of a color such as blue, purple, blue-violet, green, yellow-green, yellow, orange, or red may be used as appropriate. In addition, a material that emits near-infrared light may also be used as the luminescent material.

[0256] Examples of luminescent materials include fluorescent materials, phosphorescent materials, TADF materials, or 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, or naphthalene derivatives.

[0258] Examples of phosphorescent materials include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton; organometallic complexes (especially iridium complexes) using phenylpyridine derivatives having electron-withdrawing groups as ligands; platinum complexes; or rare earth metal complexes.

[0259] The light-emitting layer may contain one or more types of organic compounds (e.g., a host material or an assist material) in addition to the light-emitting substance (guest material). One or more of these organic compounds may be hole-transporting materials and electron-transporting materials, or both. Alternatively, one or more of these organic compounds may be bipolar materials or TADF materials.

[0260] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that emits light overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting element.

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

[0262] The formation of excited complexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing that the emission spectrum of the mixed film shifts to longer wavelengths (or has a new peak on the longer wavelength side) compared to the emission spectra of each individual material. Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing differences in the transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component or a larger proportion of the delayed component than the transient PL lifetime of each individual material. Furthermore, the transient PL mentioned above may be replaced with transient electroluminescence (EL). That is, the formation of excited complexes can also be confirmed by comparing the transient EL of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing the differences in the transient response.

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

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

[0265] Furthermore, it is preferable that the light-emitting element 61 has a microcavity structure. This allows the light emitted from the light-emitting layer 87 to resonate between the pixel electrode 84 and the common electrode 81, thereby strengthening 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 light transmission and reflectivity (a semi-transparent / semi-reflective electrode), and the other of the common electrode 81 or the pixel electrode 84 is an electrode that has reflectivity (a reflective electrode).

[0267] Alternatively, the light-emitting element 61 can have a microcavity structure by making the light-emitting layer 87IR of the light-emitting element 61IR that emits the longest wavelength light the thickest, the light-emitting layer 87R of the light-emitting element 61R that emits the next longest wavelength light the next thickest, the light-emitting layer 87G of the light-emitting element 61G that emits the next longest wavelength light the next thickest, and the light-emitting layer 87B of the light-emitting element 61B that emits the shortest wavelength light the thinnest. However, it is not limited to this, and the thickness of each light-emitting layer can be adjusted by considering, for example, the wavelength of light emitted by each light-emitting element, the optical properties of the layers constituting the light-emitting element, and the electrical properties of the light-emitting element.

[0268] The light transmittance of the transparent electrode shall be 40% or more. For example, it is preferable to use an electrode for the light-emitting element 61 that has a transmittance of 40% or more for visible light (light with a wavelength of 400 nm or more and less than 750 nm). The visible light reflectance of the semi-transparent / semi-reflective electrode shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes shall be 1 × 10⁻⁶ -2 It is preferable that the value be Ωcm or less. Furthermore, when a light-emitting element that emits near-infrared light is used in the display device, it is preferable that the transmittance and reflectance of these electrodes for near-infrared light (light with a wavelength of 750 nm to 1300 nm) are also within the above numerical range.

[0269] An insulating layer 92 is provided to cover the ends of the pixel electrode 84R, the ends of the pixel electrode 84G, the ends of the pixel electrode 84B, the ends of the pixel electrode 84IR, and the ends of the pixel electrode 84PD. The ends of the insulating layer 92 are preferably tapered. The insulating layer 92 may be omitted if it is not needed.

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

[0271] As shown in Figure 20A, a gap is provided between light-emitting elements 61 that emit light of different colors, for example, between two light-emitting layers 87. In this way, it is preferable that light-emitting layers 87R, 87G, and 87B are provided so that they do not touch each other. This effectively prevents current from flowing through two adjacent light-emitting layers 87 and causing unintended light emission. As a result, the contrast of the display device 70 can be increased, and thus the display quality of the display device 70 can be improved.

[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 into each light-emitting element from above.

[0273] The protective layer 91 may have, for example, a single-layer structure or a stacked-layer 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, and a hafnium oxide film. Alternatively, a semiconductor material such as indium gallium oxide or indium gallium zinc oxide may be used as the protective layer 91, for example.

[0274] In this specification and the like, a silicon oxynitride film refers to a film having a composition in which the oxygen content is higher than the nitrogen content. Further, a silicon nitride oxide film refers to a film having a composition in which the nitrogen content is higher than the oxygen content.

[0275] Further, as the protective layer 91, a stacked film of an inorganic insulating film and an organic insulating film can also be used. For example, a structure 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 planarization film. This allows the upper surface of the organic insulating film to be flat, thereby improving the coverage of the inorganic insulating film provided thereover and enhancing the barrier property. In addition, since the upper surface of the protective layer 91 becomes flat, this is preferable when a structure (e.g., a color filter, an electrode of a touch sensor, a lens array, or the like) is provided above the protective layer 91, because the influence of uneven shapes caused by the underlying structure can be reduced.

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

[0277] Figure 20D shows a connection portion 93 where the connecting electrode 82 and the common electrode 81 are electrically connected. In the connection portion 93, the common electrode 81 is placed in contact with the connecting 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 connecting electrode 82.

[0278] Figures 20A to 20C show a configuration in which an insulating layer 92 is provided covering the ends of pixel electrode 84R, pixel electrode 84G, pixel electrode 84B, and pixel electrode 84PD, but the present invention is not limited to this. As shown in Figure 20E, the insulating layer 92 may not be provided.

[0279] Furthermore, insulating layers 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. Figure 20E is a cross-sectional view corresponding to the dashed line A1-A2 in Figure 18B. In Figure 20E, insulating layer 94 and insulating layer 96 are provided in the region.

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

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

[0282] It is preferable that the insulating layer 94 covers at least the sides of the pixel electrode 84R, pixel electrode 84G, and pixel electrode 84B. Furthermore, it is preferable that the insulating layer 94 covers the sides of the 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. The insulating layer 94 can be configured to be in contact with the respective sides 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 the recesses formed in the insulating layer 94. The insulating layer 96 can be configured to overlap with the sides of each of the pixel electrodes 84R, 84G, 84B, hole injection layer 85R, 85G, 85B, hole transport layer 86R, 86G, 86B, light-emitting layer 87R, 87G, 87B, electron transport layer 88R, 88G, and electron transport layer 88B via the insulating layer 94.

[0284] Furthermore, it is not necessary to provide either the insulating layer 94 or the insulating layer 96. If the insulating layer 94 is not provided, the insulating layer 96 can be configured to be in contact with the respective sides of the light-emitting layers 87R, 87G, and 87B. The display device may also have an insulating layer covering the ends of the pixel electrodes. In this case, one or both of the insulating layers 94 and 96 may be provided on the insulating layer.

[0285] The common layer 89 and common electrode 81 are provided on electron transport layers 88R, 88G, 88B, insulating layer 94, and insulating layer 96. Before the insulating layers 94 and 96 are provided, a step difference exists due to the region where the pixel electrode and light-emitting layer are provided and the region where the pixel electrode and light-emitting layer are not provided (the region between light-emitting elements). In one embodiment of the present invention, the display device has insulating layers 94 and 96, which can flatten this step difference and improve the coverage of the common layer 89 and common electrode 81. Therefore, connection failures due to step breaks can be suppressed. Alternatively, the increase in electrical resistance due to local thinning of the common electrode 81 caused by the step difference can be suppressed.

[0286] To improve the flatness of the formation surfaces of the common layer 89 and the common electrode 81, it is preferable that the heights of the upper surfaces of the insulating layer 94 and the upper surface of the insulating layer 96 match or approximately match the height of at least one of the upper surfaces of the electron transport layers 88R, 88G, and 88B, respectively. Furthermore, it is preferable that the upper surface of the insulating layer 96 has a flat shape, but it may have convex or concave portions.

[0287] The insulating layer 94 has regions that are in contact with the sides 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. By providing the insulating layer 94, it is possible to suppress the intrusion of impurities (such as oxygen or moisture) into the interior from the sides of the light-emitting layers 87R, 87G, and 87B, resulting in a highly reliable display device.

[0288] In a cross-sectional view, if the width (thickness) of the insulating layer 94 in the region in contact with the sides of the light-emitting layers 87R, 87G, and 87B is large, the spacing between the light-emitting layers 87R, 87G, and 87B may increase, resulting in a lower aperture ratio. Conversely, in a cross-sectional view, if the width (thickness) of the insulating layer 94 in the region in contact with the sides of the light-emitting layers 87R, 87G, and 87B is small, the effect of suppressing the intrusion of impurities into the interior from the sides of the light-emitting layers 87R, 87G, and 87B may be reduced. In a cross-sectional view, the width (thickness) of the insulating layer 94 in the region in contact with the sides of the 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, more preferably 5 nm to 150 nm, more preferably 5 nm to 100 nm, more preferably 10 nm to 100 nm, and more preferably 10 nm to 50 nm. By setting the width (thickness) of the insulating layer 94 within the above range, a display device with a high aperture ratio and high reliability can be obtained.

[0289] The insulating layer 94 can be an insulating layer having an inorganic material. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used for the insulating layer 94. The insulating layer 94 may be a single layer or a laminated structure. Examples of oxide insulating 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 nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxidative nitride insulating films include silicon oxidative nitride films and aluminum oxidative nitride films. Examples of nitride oxide insulating films include silicon nitride film and aluminum nitride film. In particular, aluminum oxide is preferred because it has a high selectivity ratio with the light-emitting layer during etching and has the function of protecting the light-emitting layer during the formation of the insulating layer 96, which will be described later. In particular, by applying inorganic insulating films such as aluminum oxide films, hafnium oxide films, and silicon oxide films, formed by the ALD method, to the insulating layer 94, it is possible to form an insulating layer 94 with fewer pinholes and excellent function in protecting the light-emitting layer.

[0290] In this specification, the term "oxide-nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and the term "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, when "silicon oxynitride" is written, it refers to a material in which the oxygen content is greater than the nitrogen content, and when "silicon nitride oxide" is written, it refers to a material in which the nitrogen content is greater than the oxygen content.

[0291] The insulating layer 94 can be formed using sputtering, CVD, PLD, ALD, or the like. It is preferable to form the insulating layer 94 using the ALD method, which provides good coverage.

[0292] The insulating layer 96 provided on the insulating layer 94 has the function of flattening the recess in the insulating layer 94 formed between adjacent light-emitting devices. In other words, the presence of the insulating layer 96 improves the flatness of the surface on which the common electrode 81 is formed. Suitable insulating layers 96 include those made of organic materials. Examples of insulating layers 96 include acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used as the insulating layer 96. Furthermore, a photosensitive resin (also referred to as an organic resin) can be used as the insulating layer 96. A photoresist may be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

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

[0294] In the display device 70, the pixels 80 are composed of sub-pixels having an light-emitting element 61R, sub-pixels having an light-emitting element 61G, sub-pixels having an light-emitting element 61B, sub-pixels having an light-emitting element 61IR, and sub-pixels having a light-receiving element 62, but the present invention is not limited to this. For example, a display device different from the display device 70 shown in Figure 18A, etc., is shown in Figures 21A, 21B, 22A, 22B, 23A, and 23B.

[0295] The display device 70 shown in Figure 21A differs from the display device 70 shown in Figure 18A in that the pixels 80 are composed of sub-pixels having light-emitting elements 61R, sub-pixels having light-emitting elements 61G, sub-pixels having light-emitting elements 61B, and sub-pixels having light-receiving elements 62. In this case, the light-emitting element 61IR may be provided between the display area 95 and the connecting electrode 82. Alternatively, as shown in Figure 21B, the light-emitting element 61IR may be provided on the outer periphery of the display area 95 and the connecting electrode 82. By doing so, 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 increased.

[0296] In the display device 70 shown in Figure 21A, the light-emitting element 61IR can be provided along the outer perimeter of the display area 95. For example, it may be provided along one side of the outer perimeter of the display area 95, or it may be provided across two or more sides of the outer perimeter of the display area 95. That is, if the top surface shape of the display area 95 is rectangular, the arrangement of the light-emitting element 61IR in a top view can be, for example, a strip, an L-shape, a U-shape (square bracket shape), or a rectangle.

[0297] In the display device 70 shown in Figure 21B, the light-emitting element 61IR can be provided along the outer circumference of the connecting electrode 82. For example, it may be provided along one side of the outer circumference of the connecting electrode 82, or it may be provided across two or more sides of the outer circumference of the connecting electrode 82. That is, if the top surface shape of the connecting electrode 82 is rectangular, the arrangement of the light-emitting element 61IR in a top view can be, for example, a strip, an L-shape, a U-shape (square bracket shape), or a rectangle.

[0298] Furthermore, while Figures 21A and 21B show an example where the width of the light-emitting element 61IR in the Y direction is approximately the same as the width of the pixel 80 in the Y direction, the present invention is not limited to this. The width of the light-emitting element 61IR in the Y direction may be greater than or less than the width of the pixel 80 in the Y direction. Also, while Figures 21A and 21B show an example where the number of light-emitting elements 61IR in the Y direction is the same as the number of pixels 80, 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, while Figures 21A and 21B show an example where there is one light-emitting element 61IR in the X direction, the present invention is not limited to this. The number of light-emitting elements 61IR in the X direction may be multiple.

[0299] The display device 70 shown in Figure 22A differs from the display device 70 shown in Figure 18A in that the pixels 80 are composed of sub-pixels having an light-emitting element 61R, sub-pixels having an light-emitting element 61G, sub-pixels having an light-emitting element 61B, and sub-pixels having an light-emitting element 61IR. In this case, the light-receiving element 62 may be provided between the display area 95 and the connecting electrode 82. Alternatively, as shown in Figure 22B, the light-receiving element 62 may be provided on the outer periphery of the display area 95 and the connecting electrode 82. By doing so, 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 increased.

[0300] In the display device 70 shown in Figure 22A, the light-receiving elements 62 can be provided along the outer periphery of the display area 95. For example, they may be provided along one side of the outer periphery of the display area 95, or they may be provided across two or more sides of the outer periphery of the display area 95. That is, if the top surface shape of the display area 95 is rectangular, the arrangement of the light-receiving elements 62 in a top view can be, for example, a strip, an L-shape, a U-shape (angle bracket shape), or a rectangle.

[0301] In the display device 70 shown in Figure 22B, the light-receiving elements 62 can be provided along the outer circumference of the connecting electrode 82. For example, they may be provided along one side of the outer circumference of the connecting electrode 82, or they may be provided across two or more sides of the outer circumference of the connecting electrode 82. That is, if the top surface shape of the connecting electrode 82 is rectangular, the arrangement of the light-receiving elements 62 in a top view can be, for example, a strip, an L-shape, a U-shape (angle bracket shape), or a square.

[0302] Furthermore, while Figures 22A and 22B show an example where 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, the present invention is not limited to this. The width of the light-receiving element 62 in the Y direction may be greater than or less than the width of the pixel 80 in the Y direction. Also, while Figures 22A and 22B show an example where the number of light-receiving elements 62 in the Y direction is the same as the number of pixels 80, 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, while Figures 22A and 22B show an example where there is one light-receiving element 62 in the X direction, the present invention is not limited to this. The number of light-receiving elements 62 in the X direction may be multiple.

[0303] The display device 70 shown in Figure 23A differs from the display device 70 shown in Figure 18A in that the pixels 80 are composed of sub-pixels having an element-emitting element 61R, sub-pixels having an element-emitting element 61G, and sub-pixels having an element-emitting element 61B. In this case, the element-emitting element 61IR and the light-receiving element 62 may be placed between the display area 95 and the connecting electrode 82. Alternatively, as shown in Figure 23B, the element-emitting element 61IR and the light-receiving element 62 may be placed on the outer periphery of the display area 95 and the connecting electrode 82. By doing so, the length in the Y direction of the element-emitting element 61R, element-emitting element 61G, and element-emitting element 61B can be increased, thereby increasing the brightness of the light emitted by the pixels 80.

[0304] In the display device 70 shown in Figure 23A, the light-emitting element 61IR and the light-receiving element 62 can be arranged along the outer perimeter of the display area 95. For example, they may be arranged along one side of the outer perimeter of the display area 95, or they may be arranged across two or more sides of the outer perimeter of the display area 95. That is, if the top surface shape of the display area 95 is rectangular, the arrangement of the light-emitting element 61IR and the light-receiving element 62 in a top view can be, for example, a strip, an L-shape, a U-shape (angle bracket shape), or a rectangle. Furthermore, the arrangement of the light-emitting element 61IR and the light-receiving element 62 may be different. For example, the light-emitting element 61IR in a top view may be arranged on two opposing sides of the display area 95, and the light-receiving element 62 in a top view may be arranged on two sides other than the two sides mentioned above.

[0305] In the display device 70 shown in Figure 23B, the light-emitting element 61IR and the light-receiving element 62 can be arranged along the outer circumference of the connecting electrode 82. For example, they may be arranged along one side of the outer circumference of the connecting electrode 82, or they may be arranged along two or more sides of the outer circumference of the connecting electrode 82. That is, if the top surface shape of the connecting electrode 82 is rectangular, the arrangement of the light-emitting element 61IR and the light-receiving element 62 in a top view can be, for example, a strip, an L-shape, a U-shape (angle bracket shape), or a square. Furthermore, the arrangement of the light-emitting element 61IR and the light-receiving element 62 may be different. For example, the light-emitting element 61IR in a top view may be arranged on two opposing sides of the connecting electrode 82, and the light-receiving element 62 in a top view may be arranged on two sides other than the two sides mentioned above.

[0306] Furthermore, Figures 23A and 23B show an example where 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 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 than or less than the Y-direction width of the pixel 80. Also, Figures 23A and 23B show an example where the number of light-emitting elements 61IR, the number of light-receiving elements 62, and the number of pixels 80 are the same in the Y-direction, but 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. Furthermore, the number of light-emitting elements 61IR and the number of light-receiving elements 62 may be different in the Y-direction. Furthermore, while Figures 23A and 23B show an example in which there is one light-emitting element 61IR and one photodetector 62 in the X direction, the present invention is not limited to this. The number of light-emitting elements 61IR and photodetectors 62 in the X direction may be multiple.

[0307] <Example of light-emitting element configuration> As shown in Figure 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 composed of multiple layers, such as layer 4420, light-emitting layer 4411, and layer 4430. Layer 4420 may include, for example, a layer containing a material with high electron injection properties (electron injection layer) and a layer containing a material with high electron transport properties (electron transport layer). Light-emitting layer 4411 may include, for example, a light-emitting compound. Layer 4430 may include, for example, a layer containing a material with high hole injection properties (hole injection layer) and a layer containing a material with high hole transport properties (hole transport layer).

[0308] A configuration having a layer 4420, an emissive layer 4411, and a layer 4430 provided between a pair of electrodes can function as a single emissive unit, and in this specification, the configuration shown in Figure 24A is referred to as a single structure.

[0309] Furthermore, Figure 24B shows a modified example of the EL layer 686 of the light-emitting element shown in Figure 24A. Specifically, the light-emitting element shown in Figure 24B has a layer 4430-1 on electrode 672, a layer 4430-2 on layer 4430-1, an emissive layer 4411 on layer 4430-2, a layer 4420-1 on emissive layer 4411, a layer 4420-2 on layer 4420-1, and an electrode 688 on layer 4420-2. For example, when electrode 672 is the anode and electrode 688 is the cathode, layer 4430-1 functions as a hole injection layer, layer 4430-2 functions as a hole transport layer, layer 4420-1 functions as an electron transport layer, and layer 4420-2 functions as an electron injection layer. Alternatively, when electrode 672 is used as the cathode and electrode 688 as the anode, layer 4430-1 functions as an electron injection layer, layer 4430-2 functions as an electron transport layer, layer 4420-1 functions as a hole transport layer, and layer 4420-2 functions as a hole injection layer. This layer structure allows for efficient injection of carriers into the light-emitting layer 4411 and improves the efficiency of carrier recombination within the light-emitting layer 4411.

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

[0311] Furthermore, as shown in Figure 24D, a configuration in which multiple light-emitting units (EL layer 686a and EL layer 686b) are connected in series via an intermediate layer (charge generation layer) 4440 is referred to as a tandem structure in this specification. In this specification, the configuration shown in Figure 24D is referred to as a tandem structure, but it is not limited to this, and for example, a tandem structure may also be called a stack structure. By using a tandem structure, a light-emitting element capable of high-brightness light emission can be made.

[0312] Furthermore, in Figures 24C and 24D, as shown in Figure 24B, layer 4420 and layer 4430 may be a laminated structure consisting of two or more layers.

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

[0314] Furthermore, when comparing the single structure, tandem structure, and SBS structure described above, power consumption can be reduced in the order of SBS structure, tandem structure, and single structure. If you want to keep power consumption low, the SBS structure is preferable. On the other hand, the single structure and tandem structure are preferable because their manufacturing process is simpler than that of the SBS structure, which can lead to lower manufacturing costs or 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 enhanced by adding a microcavity structure to the light-emitting element.

[0316] A light-emitting element that emits white light preferably has a configuration that includes two or more types of light-emitting materials in its light-emitting layer. When obtaining white light emission using two types of light-emitting materials, the light-emitting materials should be selected such that the colors of the light emitted by each of the two materials are complementary colors. For example, by making the light-emitting color of the first light-emitting material and the light-emitting color of the second light-emitting material complementary colors, a light-emitting element that emits white light as a whole can be obtained. Also, when obtaining white light emission using three or more types of light-emitting materials, the light-emitting element can be made to emit white light as a whole by combining the colors of the light emitted by each of the three or more types of light-emitting materials.

[0317] The light-emitting layer preferably contains two or more light-emitting materials that emit light, such as R (red), G (green), B (blue), Y (yellow), or O (orange). Alternatively, it is preferable to have two or more light-emitting materials, and the light emitted by each light-emitting material contains spectral components of two or more colors from R, G, and B.

[0318] <Example of light-emitting element and light-receiving element configuration> One embodiment of the present invention is a top-emission type display device that emits light in the direction opposite to the substrate on which the light-emitting element is formed. In this embodiment, a display device equipped with a top-emission type light-emitting element and a light-receiving element will be described as an example.

[0319] In this specification, unless otherwise specified, when describing a configuration having multiple elements (for example, light-emitting elements or light-emitting layers), the letters will be omitted when describing matters common to each element. For example, when describing matters common to light-emitting layers 383R and 383G, etc., it may be written as light-emitting layer 383.

[0320] The display device 380A shown in Figure 25 includes 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 (IR) light.

[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 has a light-emitting material that emits red light, light-emitting layer 383G has a light-emitting material that emits green light, light-emitting layer 383B has a light-emitting material that emits blue light, and light-emitting layer 383IR has a light-emitting material that emits infrared light.

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

[0323] The photodetector 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, both the light-emitting element and the light-receiving element are described as having a pixel electrode 371 functioning as the anode and a common electrode 375 functioning as the cathode. In other words, the light-receiving element can detect light incident on it, generate an electric charge, and extract it as an electric current by driving it with a reverse bias applied between the pixel electrode 371 and the common electrode 375.

[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 have the same configuration as those of 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. Thus, the light-receiving element 370PD can be incorporated into the display device without significantly increasing the manufacturing process.

[0327] In the display device 380A, an example is shown where 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 element 383 are manufactured separately. However, the configuration of the light-receiving element 370PD and the light-emitting element is not limited to this. In addition to the active layer 373 and the light-emitting layer 383, the light-receiving element 370PD and the light-emitting element may have layers that are manufactured separately from each other. It is preferable that the light-receiving element 370PD and the light-emitting element have one or more layers that are used in common (common layers). This makes it possible to incorporate the light-receiving element 370PD into the display device without significantly increasing the manufacturing process.

[0328] Of the pixel electrode 371 and the common electrode 375, the electrode that extracts light preferably uses a conductive film that transmits visible light. Furthermore, it is preferable to use a conductive film that reflects visible light on the electrode that does not extract light.

[0329] In this embodiment, it is preferable that the light-emitting element of the display device has a microcavity structure. Therefore, it is preferable that one of the pair of electrodes of the light-emitting element has an electrode that is transparent to and reflective to visible light (a semi-transmitting / semi-reflective electrode), and the other has an electrode that is reflective to visible light (a reflective electrode). By having a microcavity structure in the light-emitting element, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby strengthening the light emitted from the light-emitting element.

[0330] The light transmittance of the transparent electrode shall be 40% or more. For example, it is preferable to use an electrode with a visible light transmittance (light with a wavelength of 400 nm or more and less than 750 nm) of 40% or more in the light-emitting element. The visible light reflectance of the semi-transparent / semi-reflective electrode shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. Furthermore, the resistivity of these electrodes shall be 1 × 10⁻⁶ -2 It is preferable that the value be Ωcm or less. Furthermore, if the light-emitting element emits near-infrared light (light with a wavelength of 750 nm to 1300 nm), it is preferable that the transmittance or reflectance of these electrodes for near-infrared light satisfies the above numerical range, similar to the transmittance or reflectance for visible light.

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

[0332] For example, the light-emitting element and the light-receiving element may share one or more layers selected from among a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer. Further, the light-emitting element and the light-receiving element may have one or more layers separately formed from each other selected from among a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

[0333] In the light-receiving element, the hole transport layer is a layer that transports holes generated based on light incident on an active layer to an anode. Further, in the light-receiving element, the electron transport layer is a layer that transports electrons generated based on light incident on the active layer to a 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 content described in <Schematic top view of a light-emitting element and its periphery and schematic cross-sectional view thereof> can be referred to.

[0335] The active layer 373 contains a semiconductor. Examples of the semiconductor include inorganic semiconductors such as silicon, and organic semiconductors containing organic compounds. In the present embodiment, an example in which an organic semiconductor is used as the semiconductor included in the active layer 373 is described. Use of an organic semiconductor is preferable because the light-emitting layer 383 and the active layer 373 can be formed by the same method (e.g., vacuum vapor deposition) and manufacturing equipment can be shared.

[0336] Examples of the material of the n-type semiconductor included in the active layer 373 include fullerenes (e.g., C60, C 70Examples include electron-accepting organic semiconductor materials such as benzene, cellulose, or fullerene derivatives. Fullerenes have a shape like a soccer ball, and this shape is energetically stable. Fullerenes have deep (low) HOMO and LUMO levels. Because fullerenes have a deep LUMO level, they have extremely high electron-accepting properties. Normally, when π-electron conjugation (resonance) spreads out in a plane, as in benzene, electron-donating properties increase, but because fullerenes have a spherical shape, they have high electron-accepting properties despite the large spread of π-electron conjugation. High electron-accepting properties allow for fast and efficient charge separation, making them useful as photodetectors. 60 , C 70 Both have a broad absorption band in the visible light region, and especially C 70 is C 60 Compared to [another compound], it is preferable because it has a larger π-electron conjugation system and a broad absorption band in the long-wavelength region. Other examples of fullerene derivatives include [6,6]-Phenyl-C71-butyric acid methyl ester (abbreviated as PC70BM), [6,6]-Phenyl-C61-butyric acid methyl ester (abbreviated as PC60BM), or 1',1'',4',4''-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2'',3''][5,6]fullerene-C60 (abbreviated as ICBA).

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

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

[0339] Furthermore, examples of materials for p-type semiconductors include carbazole derivatives, thiophene derivatives, furan derivatives, or compounds having an aromatic amine skeleton. In addition, examples of materials for p-type semiconductors 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, or polythiophene derivatives.

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

[0341] It is preferable to use spherical fullerenes as electron-accepting organic semiconductor materials and organic semiconductor materials with a near-planar shape as electron-donating organic semiconductor materials. Molecules with similar shapes tend to aggregate, and when molecules of the same type aggregate, their molecular orbital energy levels are close, which can improve carrier transport.

[0342] For example, the active layer 373 is preferably formed by co-depositing an n-type semiconductor and a p-type semiconductor. Alternatively, the active layer 373 may be formed by stacking an n-type semiconductor and a p-type semiconductor.

[0343] The light-emitting element and the light-receiving element may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting element and the light-receiving element can be formed, for example, by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, or coating.

[0344] For example, as hole-transporting materials, polymer compounds such as poly(3,4-ethylenedioxythiophene) / (polystyrene sulfonic acid) (abbreviated as PEDOT / PSS), and inorganic compounds such as molybdenum oxide or copper iodide (CuI) can be used. Furthermore, as electron-transporting materials, inorganic compounds such as zinc oxide (ZnO) can be used.

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

[0346] Furthermore, the active layer 373 may contain a mixture of three or more materials. For example, to broaden the wavelength range, a third material may be mixed with 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] <Example of display device configuration> Figure 26 is a cross-sectional view showing an example of the configuration of the display device 70. The display device 70 has a configuration in which a transistor 310 with a channel formed on a substrate 301 and a transistor 320 containing a metal oxide in the semiconductor layer where the channel is formed are stacked.

[0348] An insulating layer 261 is provided covering the transistor 310, and a conductive layer 251 is provided on the insulating layer 261. The conductive layer 251 is electrically connected to either the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. An insulating layer 262 is provided covering the conductive layer 251, and a conductive layer 252 is provided on the insulating layer 262. The conductive layers 251 and 252 each function as wiring. An insulating layer 263 and an insulating layer 332 are provided covering the conductive layer 252, and a transistor 320 is provided on the insulating layer 332. An insulating layer 265 is provided covering the transistor 320, and a capacitor 240 is provided on the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0349] Transistor 320 can be used as a transistor constituting a pixel circuit or a transistor constituting a memory cell. Transistor 310 can be used as a transistor constituting a memory cell, a transistor constituting a drive circuit for driving the pixel circuit, or a transistor constituting an arithmetic circuit. Transistors 310 and 320 can also be used as transistors constituting various circuits, such as arithmetic circuits or memory circuits.

[0350] The transistor 310 is a transistor having a channel-forming region in the substrate 301. The substrate 301 can be a semiconductor substrate such as a single-crystal silicon substrate. The transistor 310 comprises a portion 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 of the substrate 301 doped with impurities and functions as either a source or a drain. The insulating layer 314 covers the 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] Transistor 320 is a transistor in which a metal oxide (also called an oxide semiconductor) is applied to the semiconductor layer where the channel is formed.

[0353] The transistor 320 has 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 into the transistor 320 from the substrate 301 side, and prevents oxygen from detaching from the semiconductor layer 321 to the insulating layer 332 side. As the insulating layer 332, a film that is less susceptible to hydrogen or oxygen diffusion than a silicon oxide film can be used, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0355] A conductive layer 327 is provided on an insulating layer 332, and an insulating layer 326 is provided covering the conductive layer 327. The conductive layer 327 functions as the second gate electrode of the transistor 320, and a portion of the insulating layer 326 functions as the second gate insulating layer. It is preferable to use an oxide insulating film, such as a silicon oxide film, for at least the portion of the insulating layer 326 that is in contact with the semiconductor layer 321. It is preferable that the upper surface of the insulating layer 326 is flattened.

[0356] The conductive layer 327 may be a single layer or a stack of two or more conductive layers. When the conductive layer 327 is configured as two stacked conductive layers, it is preferable that the conductive layer in contact with the bottom surface and side wall of the opening provided in the insulating layer 326 is made of a conductive material that has the 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, or ruthenium oxide. By using this configuration, it is possible to suppress the diffusion of impurities such as water or hydrogen into the semiconductor layer 321.

[0357] The insulating layer 326 may be an inorganic insulating film, either as a single layer or by stacking two or more layers. When two or more inorganic insulating films are stacked as the insulating layer 326, it is preferable that one of the inorganic insulating films of the insulating layer 326 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing from the substrate 301 to the transistor 320. The same insulating film as the insulating layer 328 can be used as the inorganic insulating film.

[0358] The semiconductor layer 321 is provided on the insulating layer 326. Preferably, the semiconductor layer 321 has a metal oxide (also called an oxide semiconductor) film having semiconductor properties. Preferably, the semiconductor layer 321 uses a metal oxide containing at least one of indium, element M (where element M is aluminum, gallium, yttrium, or tin), and zinc. OS transistors using such metal oxides in the channel formation region have the characteristic of having a very low off-current. Therefore, using an OS transistor as a transistor provided in a pixel circuit is preferable because it can retain analog data written to the pixel circuit for a long period of time. Similarly, using an OS transistor as a transistor used in a memory cell is preferable because it can retain analog data written to the memory cell for a long period of time.

[0359] A pair of conductive layers 325 are provided in contact with the semiconductor layer 321 and function as source and drain electrodes.

[0360] Furthermore, for example, an insulating layer 328 is provided covering the top and side surfaces of a pair of conductive layers 325, as well as the side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided on the insulating layer 328. The insulating layer 328 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing into the semiconductor layer 321 from, for example, the insulating layer 264, and prevents oxygen from detaching from the semiconductor layer 321. As the insulating layer 328, an insulating film similar to that of the insulating layer 332 can be used.

[0361] An opening is provided in the insulating layer 328 and the insulating layer 264 that reaches the semiconductor layer 321. Inside this opening, the insulating layer 323 and the conductive layer 324 are embedded, in contact with the sides of the insulating layer 264, the insulating layer 328, and the conductive layer 325, as well as the upper 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] As the insulating layer 323, for example, an inorganic insulating film such as a silicon oxide film or a silicon oxynitride film can be used. Note that the insulating layer 323 is not limited to a single layer of inorganic insulating film, but may be used by laminating two or more inorganic insulating films. For example, an aluminum oxide film, a hafnium oxide film, or a silicon nitride film may be provided as a single layer or in layers on the side in contact with the conductive layer 324. This can suppress oxidation of the conductive layer 324. Alternatively, for example, an aluminum oxide film or a hafnium oxide film may be provided on the side in contact with the insulating layer 264, insulating layer 328, and conductive layer 325. This can suppress, for example, the desorption of oxygen from the semiconductor layer 321, the excessive supply of oxygen to the semiconductor layer 321, and the oxidation of the conductive layer 325.

[0363] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are flattened so that their heights are roughly the same, and the insulating layers 329 and 265 are provided covering them.

[0364] Furthermore, it is preferable that the conductive layer 327 and the conductive layer 324 are superimposed on the outer side of the side surface in the channel width direction of the semiconductor layer 321, with an insulator in between. With this configuration, the channel formation region of the semiconductor layer 321 can be electrically surrounded by the electric field of the conductive layer 327, which functions as the second gate electrode, and the electric field of the conductive layer 324, which functions as the first gate electrode. In this specification and elsewhere, a transistor structure in which the channel formation region is electrically surrounded by the electric field of the first gate electrode and the electric field of the second gate electrode is called a surrounded channel (S-channel) structure.

[0365] In this specification, an S-channel transistor refers to a transistor structure in which the channel formation region is electrically surrounded by the electric fields of one and the other of a pair of gate electrodes. Furthermore, the S-channel structure disclosed in this specification is different from the Fin-type structure and the Planar-type structure. By adopting an S-channel structure, it is possible to create a transistor that has improved resistance to short-channel effects, or in other words, a transistor in which short-channel effects are less likely to occur.

[0366] By setting transistor 320 to normally off and adopting the above-described S-Channel structure, the channel formation region can be electrically surrounded. Therefore, transistor 320 can also be considered as having a GAA (Gate All Around) structure or an LGAA (Lateral Gate All Around) structure. By making transistor 320 an S-Channel, GAA, or LGAA structure, the channel formation region formed at or near the interface between the semiconductor layer 321 and the gate insulating film can be made to encompass the entire bulk of the semiconductor layer 321. Consequently, it becomes possible to improve the current density flowing through the transistor, thereby improving the on-current of the transistor or increasing the field-effect mobility of the transistor.

[0367] Insulating layers 264 and 265 function as interlayer insulating layers. Insulating layer 329 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the transistor 320 from, for example, insulating layer 265. As insulating layer 329, an insulating film similar to that used for insulating layers 328 and 332 can be used.

[0368] A plug 274, which is electrically connected to one of the pair of conductive layers 325, is provided so as to be embedded in the insulating layers 265, 329, 264, and 328. The plug 274 is configured such that the conductive layers are provided as a single layer or a laminated structure of two or more layers. When the plug 274 is configured as a laminated structure of two conductive layers, it is preferable to use a conductive material that does not easily allow hydrogen and oxygen to diffuse as the conductive layer that covers the sides of the openings of the insulating layers 265, 329, 264, and 328, and a part of the upper surface of the conductive layer 325. This configuration makes it possible to suppress the mixing of impurities such as water or hydrogen from, for example, the insulating layer 264, etc., into the semiconductor layer 321 through the plug 274. It also makes it possible to suppress the absorption of oxygen contained in the insulating layer 264 into the plug 274.

[0369] Furthermore, an insulating layer 275 is provided in contact with the side surface of the plug 274. In other words, the insulating layer 275 may be 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 may be provided in contact with the side surface of the insulating layer 275 and a part of the upper surface of the conductive layer 325. Note that the insulating layer 275 may not be provided in some cases.

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

[0371] The conductive layer 245 is provided on the insulating layer 265 and embedded in the insulating layer 254. The conductive layer 245 is electrically connected to either the source or drain of the transistor 320 by a plug 274 embedded in the insulating layer 265, insulating layer 329, insulating layer 264, and insulating layer 328. The insulating layer 243 is provided covering the conductive layer 245. The conductive layer 241 is provided in the region that overlaps with the conductive layer 245 via the insulating layer 243.

[0372] An insulating layer 255 is provided covering the capacitance 240, and on the insulating layer 255, for example, a light-emitting element 61 and a light-receiving element 62 are provided. 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 for 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 plugs 256 embedded in the insulating layer 255 and insulating layer 243, a conductive layer 245 embedded in the insulating layer 254, and plugs 274 embedded in the insulating layer 265, insulating layer 329, insulating layer 264, and insulating layer 328.

[0374] This configuration allows for the placement of OS transistors constituting the pixel circuit and memory cell directly beneath the light-receiving element and light-emitting element, as well as the placement of, for example, a drive circuit and an arithmetic circuit. This makes it possible to miniaturize a high-performance display device.

[0375] Figure 26 shows a configuration in which transistor 310 and transistor 320 are stacked in the display device 70. However, the configuration of the display device 70 is not limited to this. The display device 70 may have a configuration that includes transistor 310 but does not include transistor 320, or a configuration that does not include transistor 310 but includes transistor 320, or a configuration in which multiple transistors 320 are stacked, or a configuration in which transistor 310 and multiple transistors 320 are stacked on top of transistor 310.

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

[0377] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part.

[0378] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0379] (Embodiment 4) This embodiment describes a transistor that can be used in a display device according to one aspect of the present invention.

[0380] <Example of transistor configuration> Figures 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 aspect of the present invention. The transistor 500 can be applied to a display device according to one aspect of the present invention.

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

[0382] As shown in Figure 27, the transistor 500 includes a metal oxide 531a disposed on a substrate (not shown), a metal oxide 531b disposed on top of the metal oxide 531a, conductors 542a and 542b disposed on the metal oxide 531b at a distance from each other, an insulator 580 disposed on the conductors 542a and 542b with an opening formed between them, a conductor 560 disposed within the opening, and an insulator 550 disposed between the metal oxide 531b, conductors 542a, conductors 542b, insulator 580, and conductor 560. Here, as shown in Figures 27B and 27C, it is preferable that the upper surface of the conductor 560 substantially coincides with the upper surfaces of the insulators 550 and 580. In the following, metal oxides 531a and 531b may be collectively referred to as metal oxide 531. In addition, conductors 542a and 542b are sometimes collectively referred to as conductor 542.

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

[0384] In the transistor 500, a configuration is shown in which two layers of metal oxide 531a and metal oxide 531b are stacked in the region where the channel is formed (hereinafter also referred to as the channel formation region) and in its vicinity. However, the present invention is not limited to this configuration. For example, a single-layer structure of metal oxide 531b or a stacked structure of three or more layers may be provided. Furthermore, each of the metal oxide 531a and 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 the source electrode or drain electrode, respectively. As described above, the conductor 560 is formed to be embedded in the opening of the insulator 580 and in the region sandwiched between the conductors 542a and 542b. Here, the arrangement of the conductors 560, 542a, and 542b is selected in a self-aligned manner with respect to the opening of the insulator 580. In other words, in the transistor 500, the gate electrode can be positioned in a self-aligned manner between the source electrode and the drain electrode. Therefore, since the conductor 560 can be formed without providing a positional margin, the occupied area of ​​the transistor 500 can be reduced. This makes it possible to make the display device high-resolution. It also makes it possible to make the display device have a narrow bezel.

[0386] As shown in Figure 27, it is preferable that the conductor 560 has a conductor 560a provided inside the insulator 550 and a conductor 560b provided so as to be embedded inside the conductor 560a. In Figure 27, the conductor 560 is shown as a two-layer laminated structure, but the present invention is not limited to this. For example, the conductor 560 may be a single-layer structure or a laminated 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 top of the insulator 514, a conductor 505 disposed so as to be embedded in the insulator 516, an insulator 522 disposed on top of the insulator 516 and the conductor 505, and an insulator 524 disposed on top of the insulator 522. It is preferable that a metal oxide 531a is disposed on top of the insulator 524.

[0388] As shown in Figure 27, it is preferable that an insulator 554 is placed between insulator 522, insulator 524, metal oxide 531a, metal oxide 531b, conductor 542a, conductor 542b, and insulator 550 and insulator 580. Here, it is preferable that the insulator 554 is in contact with the side surface of insulator 550, the top and side surface of conductor 542a, the top and side surface of conductor 542b, the side surface of metal oxide 531a, metal oxide 531b, and insulator 524, and the top surface of insulator 522, as shown in Figures 27B and 27C.

[0389] It is preferable that insulators 574 and 581, which function as interlayer films, are placed on top of the transistor 500. Here, it is preferable that insulator 574 is placed in contact with the upper surfaces of the conductor 560, insulator 550, and insulator 580.

[0390] It is preferable that insulators 522, 554, and 574 have a function to suppress the diffusion of hydrogen (for example, at least one such as hydrogen atoms and hydrogen molecules). For example, it is preferable that insulators 522, 554, and 574 have lower hydrogen permeability than insulators 524, 550, and 580. It is also preferable that insulators 522 and 554 have a function to suppress the diffusion of oxygen (for example, at least one such as oxygen atoms and oxygen molecules). For example, it is preferable that insulators 522 and 554 have lower oxygen permeability than insulators 524, 550, and 580.

[0391] It is preferable that a conductor 545 (conductor 545a and conductor 545b) is provided that is electrically connected to the transistor 500 and functions as a plug. In addition, an 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 wall of the opening of the insulator 554, insulator 580, insulator 574, and insulator 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 inside. Here, the height of the upper surface of the conductor 545 and the height of the upper surface of the insulator 581 can be made to be approximately the same. Although the transistor 500 shows a configuration in which the first conductor and the second conductor of the conductor 545 are stacked, the present invention is not limited to this. For example, the conductor 545 may be provided as a single layer or as a laminated structure of three or more layers. When the structure has a laminated structure, an ordinal number may be assigned to distinguish it according to the order of formation.

[0392] In transistor 500, it is preferable to use a metal oxide that functions as an oxide semiconductor (hereinafter also referred to as an oxide semiconductor) for the metal oxide 531 (metal oxide 531a and metal oxide 531b) that includes the channel formation region. For example, it is preferable to use a metal oxide with a band gap of 2 eV or more, preferably 2.5 eV or more, as the metal oxide that forms the channel formation region of metal oxide 531.

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

[0394] Furthermore, the thickness of the metal oxide 531b in the region that does not overlap with the conductor 542 may be thinner than the thickness of the metal oxide 531b in the region that overlaps with the conductor 542. This is formed by removing a portion of the upper surface of the metal oxide 531b when forming the conductors 542a and 542b. When a conductive film that will become the conductor 542 is deposited on the upper surface of the metal oxide 531b, a region with low resistance may be formed near the interface with the conductive film. In this way, by removing the region with low resistance located between the conductors 542a and 542b on the upper surface of the metal oxide 531b, it is possible to prevent the formation of a channel in that region.

[0395] According to one aspect of the present invention, a display device with high resolution can be provided by having a small-sized transistor. Alternatively, a display device with high brightness can be provided by having a transistor with a large on-current. Alternatively, a display device with fast operation can be provided by having a fast-operating transistor. Alternatively, a display device with high reliability can be provided by having a transistor with stable electrical characteristics. Alternatively, a display device with low power consumption can be provided by having a transistor with a small off-current.

[0396] A detailed configuration of the transistor 500, which can be used in a display device according to one aspect of the present invention, will be described.

[0397] The conductor 505 is arranged to have an overlapping region with the metal oxide 531 and the conductor 560. Furthermore, it is preferable that the conductor 505 is embedded in the insulator 516.

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

[0399] It is preferable to use a conductive material for the conductor 505a that has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (e.g., N2O, NO, or NO2), or copper atoms. Alternatively, it is preferable to use a conductive material that has the function of suppressing the diffusion of oxygen (e.g., at least one such as oxygen atoms and oxygen molecules).

[0400] By using a conductive material that has the function of reducing hydrogen diffusion for the conductor 505a, it is possible to suppress the diffusion of impurities such as hydrogen contained in the conductor 505b into the metal oxide 531 via, for example, the insulator 524. Furthermore, by using a conductive material that has the function of suppressing oxygen diffusion for the conductor 505a, it is possible to suppress the oxidation of the conductor 505b and the resulting decrease in conductivity. As a conductive material that has the function of suppressing oxygen diffusion, it is preferable to use, for example, titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, or ruthenium oxide. Therefore, the conductor 505a can be made of the above conductive material in a single layer or a laminate. For example, titanium nitride can be used for the conductor 505a.

[0401] Furthermore, it is preferable to use a conductive material whose main component is tungsten, copper, or aluminum for the conductor 505b. For example, tungsten may be used for the conductor 505b.

[0402] Here, conductor 560 may function as the first gate (also called the top gate) electrode. Also, conductor 505 may function as the second gate (also called the bottom gate) electrode. In that case, by changing the potential applied to conductor 505 independently of the potential applied to conductor 560, the V of transistor 500 can be controlled. th This can be controlled. In particular, by applying a negative potential to the conductor 505, the V of transistor 500 can be controlled. t h This makes it possible to increase the voltage and reduce the off-current. Therefore, applying a negative potential to the conductor 505 reduces the drain current when the potential applied to the conductor 560 is 0V compared to when no potential is applied.

[0403] The conductor 505 should be larger than the channel-forming region in the metal oxide 531. In particular, as shown in Figure 27C, it is preferable that the conductor 505 extends beyond the end of the metal oxide 531 that intersects with the channel width direction. That is, it is preferable that the conductor 505 and the conductor 560 are superimposed on the outer side of the side surface in the channel width direction of the metal oxide 531, with an insulator in between.

[0404] With the above configuration, the channel-forming region of the metal oxide 531 can be electrically surrounded by the electric field of the conductor 560, which functions as the first gate electrode, and the electric field of the conductor 505, which functions as the second gate electrode.

[0405] As shown in Figure 27C, the conductor 505 is extended to function as wiring. However, the configuration is not limited to this, and a conductor that functions as wiring may be provided beneath the conductor 505.

[0406] The insulator 514 preferably functions as a barrier insulating film that suppresses the ingress of impurities such as water or hydrogen from the substrate side into the transistor 500. Therefore, it is preferable to use an insulating material for the insulator 514 that has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (e.g., N2O, NO, or NO2), or copper atoms (the above impurities are less permeable). Alternatively, it is preferable to use an insulating material that has the function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules) (the above oxygen is less permeable).

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

[0408] The insulators 516, 580, and 581, which function as interlayer films, preferably have a lower dielectric constant than insulator 514. By using a material with a low dielectric constant as the interlayer film, parasitic capacitance between wiring can be reduced. For example, as insulators 516, 580, and 581, appropriate materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, or silicon oxide with vacancies may be used.

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

[0410] Here, it is preferable that the insulator 524 in contact with the metal oxide 531 desorbs oxygen upon heating. In this specification, the oxygen that is desorbed upon heating is sometimes referred to as excess oxygen. The insulator 524 may be, for example, silicon oxide or silicon oxynitride. By providing an oxygen-containing insulator in contact with the metal oxide 531, the oxygen deficiency in the metal oxide 531 can be reduced, and the reliability of the transistor 500 can be improved.

[0411] Specifically, it is preferable to use an oxide material in which some oxygen is desorbed upon heating as the insulator 524. An oxide that desorbs oxygen upon heating is one in which the amount of oxygen desorbed, converted to oxygen atoms as obtained by TDS (Thermal Desorption Spectroscopy) analysis, is 1.0 × 10⁻⁶. 18 atoms / cm 3 Preferably 1.0 × 10 19 atoms / cm 3 More preferably 2.0 × 10 19 atoms / cm 3 Above, or 3.0 × 10 20 atoms / cm 3 The oxide film is as described above. The surface temperature of the film during the TDS analysis is preferably in the range of 100°C to 700°C, or 100°C to 400°C.

[0412] The insulator 522 preferably functions as a barrier insulating film that suppresses the ingress of impurities such as water or hydrogen into the transistor 500 from the substrate side, similar to, for example, the insulator 514. For example, the insulator 522 preferably has lower hydrogen permeability than the insulator 524. By surrounding, for example, the insulator 524, the metal oxide 531, and the insulator 550 with the insulator 522, the insulator 554, and the insulator 574, it is possible to suppress the ingress of impurities such as water or hydrogen into the transistor 500 from the outside.

[0413] Furthermore, it is preferable that the insulator 522 has a function to suppress the diffusion of oxygen (for example, at least one such as oxygen atoms and oxygen molecules) (i.e., it is difficult for the above-mentioned oxygen to permeate it). For example, it is preferable that the insulator 522 has lower oxygen permeability than the insulator 524. It is preferable that the insulator 522 has a function to suppress the diffusion of oxygen and impurities, thereby reducing the diffusion of oxygen contained in the metal oxide 531 to the substrate side. In addition, it is possible to suppress the reaction of the conductor 505 with the oxygen contained in the insulator 524 and the metal oxide 531.

[0414] The insulator 522 may be an insulator containing an oxide of one or both of aluminum and hafnium, which are insulating materials. For example, it is preferable to use aluminum oxide, hafnium oxide, or an oxide containing both aluminum and hafnium (hafnium aluminate) as the insulator containing one or both of aluminum and hafnium. When the insulator 522 is formed using such a material, the insulator 522 functions as a layer that suppresses the release of oxygen from the metal oxide 531 and the incorporation of impurities such as hydrogen from the periphery of the transistor 500 into the metal oxide 531.

[0415] Alternatively, these insulators may be to which, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, or zirconium oxide may be added. Alternatively, these insulators may be subjected to nitriding treatment. Silicon oxide, silicon oxide nitride, or silicon nitride may be laminated onto the above insulators.

[0416] The insulator 522 may be a single-layer or multi-layer insulator containing so-called high-k materials such as aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3), or (Ba,Sr)TiO3 (BST). As transistors become smaller and more integrated, thinning of the gate insulator can lead to problems such as leakage current. 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] Furthermore, the insulators 522 and 524 may have a laminated structure of two or more layers. In that case, the laminated structures of insulators 522 and 524 are not limited to those made of the same material, but may be made of different materials. For example, an insulator similar to that of insulator 524 may be provided below insulator 522.

[0418] The metal oxide 531 comprises a metal oxide 531a and a metal oxide 531b on the metal oxide 531a. By having the metal oxide 531a below the metal oxide 531b, the diffusion of impurities from structures formed below the metal oxide 531a to the metal oxide 531b can be suppressed.

[0419] Furthermore, it is preferable that the metal oxide 531 has a laminated structure of multiple oxide layers with different atomic ratios of each metal atom. For example, if the metal oxide 531 contains at least indium (In) and element M, it is preferable that the ratio of the number of atoms of element M contained in metal oxide 531a to the total number of atoms of all elements constituting metal oxide 531a is higher than the ratio of the number of atoms of element M contained in metal oxide 531b to the total number of atoms of all elements constituting metal oxide 531b. It is also preferable that the atomic ratio of element M contained in metal oxide 531a to In is higher than the atomic ratio of element M contained in metal oxide 531b to In.

[0420] It is preferable that the energy at the lower end of the conduction band of metal oxide 531a is higher than the energy at the lower end of the conduction band of metal oxide 531b. In other words, it is preferable that the electron affinity of metal oxide 531a is smaller than the electron affinity of metal oxide 531b.

[0421] Here, at the junction between metal oxide 531a and metal oxide 531b, the energy level at the lower end of the conduction band changes smoothly. In other words, the energy level at the lower end of the conduction band at the junction between metal oxide 531a and metal oxide 531b can be said to change continuously or be continuously joined. To achieve this, it is desirable to lower the defect level density of the mixed layer formed at the interface between metal oxide 531a and metal oxide 531b.

[0422] Specifically, a mixed layer with a low defect level density can be formed if metal oxide 531a and metal oxide 531b have a common element other than oxygen (which serves as the main component). For example, if metal oxide 531b is In-Ga-Zn oxide, then metal oxide 531a may be, for example, In-Ga-Zn oxide, Ga-Zn oxide, or gallium oxide.

[0423] Specifically, for metal oxide 531a, a metal oxide with an atomic ratio of In:Ga:Zn = 1:3:4 or 1:1:0.5 may be used. Similarly, for metal oxide 531b, a metal oxide with an atomic ratio of In:Ga:Zn = 1:1:1, 4:2:3, or 3:1:2 may be used.

[0424] In this case, the main carrier pathway is through the metal oxide 531b. By configuring the metal oxide 531a as described above, the defect level density at the interface between the metal oxide 531a and the metal oxide 531b can be reduced. As a result, the influence of interfacial scattering on carrier conduction is reduced, and the transistor 500 can obtain a high on-current and high frequency characteristics.

[0425] A conductor 542 (conductor 542a and conductor 542b) that functions as a source electrode and a drain electrode is provided on the metal oxide 531b. It is preferable to use a metal element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, and lanthanum as the conductor 542, an alloy composed of the above metal elements, or an alloy combining the above metal elements. For example, it is preferable to use tantalum nitride, titanium nitride, tungsten, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, or oxides containing lanthanum and nickel. Furthermore, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, or oxides containing lanthanum and nickel are preferred because they are conductive materials that are resistant to oxidation or maintain conductivity even when absorbing oxygen.

[0426] By providing the conductor 542 in contact with the metal oxide 531, the oxygen concentration in the vicinity of the conductor 542 on the metal oxide 531 may be reduced. Furthermore, a metal compound layer containing the metal in the conductor 542 and components of the metal oxide 531 may be formed in the vicinity of the conductor 542 on the metal oxide 531. In such cases, the carrier concentration increases in the region of the metal oxide 531 near the conductor 542, resulting in a low-resistance region.

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

[0428] The insulator 550 functions as a gate insulator. It is preferable that the insulator 550 be placed in contact with the upper surface of the metal oxide 531b. The insulator 550 can be silicon oxide, silicon oxynitride, silicon nitride, silicon nitride, fluorine-added silicon oxide, carbon-added silicon oxide, carbon and nitrogen-added silicon oxide, or porous silicon oxide. Silicon oxide or silicon oxynitride is particularly preferred because it is thermally stable.

[0429] Similar to the insulator 524, it is preferable that the insulator 550 has a reduced concentration of impurities such as water or hydrogen. The film thickness of the insulator 550 is preferably 1 nm or more and 20 nm or less.

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

[0431] A metal oxide may be provided between the insulator 550 and the conductor 560. It is preferable that the metal oxide suppresses oxygen diffusion from the insulator 550 to the conductor 560. This suppresses the oxidation of the conductor 560 by 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, it is preferable to use a metal oxide that is a high-k material with a high dielectric constant. By making the gate insulator a laminated structure of insulator 550 and the metal oxide, a laminated structure that is stable against heat and has a high dielectric constant can be made. Therefore, it becomes possible to reduce the gate potential applied during transistor operation while maintaining the physical film thickness of the gate insulator. In addition, it becomes possible to thin the equivalent oxide film thickness (EOT) of the insulator that functions as a gate insulator.

[0433] Specifically, as the insulator 550, one or more metal oxides selected from, for example, hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, or magnesium can be used. In particular, it is preferable to use an insulator that contains oxides of one or both 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 a two-layer structure in Figure 27, it may also be a single-layer structure or a multilayer structure of three or more layers.

[0435] It is preferable to use a conductor 560a that has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (e.g., N2O, NO, or NO2), or copper atoms. Alternatively, it is preferable to use a conductive material that has the function of suppressing the diffusion of oxygen (e.g., at least one such as oxygen atoms and oxygen molecules).

[0436] The conductor 560a has the function of suppressing oxygen diffusion, which prevents the conductor 560b from being oxidized by the oxygen contained in the insulator 550 and thus prevents a decrease in conductivity. It is preferable to use a conductive material that has the function of suppressing oxygen diffusion, such as tantalum, tantalum nitride, ruthenium, or ruthenium oxide.

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

[0438] As shown in Figures 27A and 27C, in the region of the metal oxide 531b that does not overlap with the conductor 542, in other words, in the channel-forming region of the metal oxide 531, the side surface of the metal oxide 531 is covered by the conductor 560. This makes it easier to apply the electric field of the conductor 560, which functions as the first gate electrode, to the side surface of the metal oxide 531. Therefore, the on-current of the transistor 500 can be increased and the frequency characteristics can be improved.

[0439] The insulator 554 preferably functions as a barrier insulating film that suppresses the ingress of impurities such as water or hydrogen into the transistor 500 from the insulator 580 side, similar to, for example, the insulator 514. For example, it is preferable that the insulator 554 has lower hydrogen permeability than the insulator 524. Furthermore, as shown in Figures 27B and 27C, it is preferable that the insulator 554 is 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 metal oxide 531a, the metal oxide 531b, and the side surface of the insulator 524. With this configuration, it is possible to suppress the ingress of hydrogen contained in the insulator 580 into 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, it is preferable that the insulator 554 has the function of suppressing the diffusion of oxygen (for example, at least one such as oxygen atoms and oxygen molecules) (i.e., it is difficult for the above-mentioned oxygen to permeate through it). For example, it is preferable that the insulator 554 has lower oxygen permeability than the insulator 580 or the insulator 524.

[0441] The insulator 554 is preferably deposited using a sputtering method. By depositing the insulator 554 using a sputtering method in an oxygen-containing atmosphere, oxygen can be added to the vicinity of the region of the insulator 524 that is in contact with the insulator 554. This allows oxygen to be supplied from this region to the metal oxide 531 via the insulator 524. Here, the insulator 554 has a function to suppress upward diffusion of oxygen, thereby preventing oxygen from diffusing from the metal oxide 531 to the insulator 580. In addition, the insulator 522 has a function to suppress downward diffusion of oxygen, thereby preventing oxygen from diffusing from the metal oxide 531 to the substrate side. In this way, oxygen is supplied to the channel formation region of the metal oxide 531. This reduces oxygen deficiency in the metal oxide 531 and suppresses normally-on formation of the transistor.

[0442] As the insulator 554, for example, an insulator containing an oxide of one or both of aluminum and hafnium may be formed as a film. It is preferable to use, for example, aluminum oxide, hafnium oxide, or an oxide containing both aluminum and hafnium (hafnium aluminate) as the insulator containing an oxide of one or both of aluminum and hafnium.

[0443] The insulator 580 is provided on the insulator 524, the metal oxide 531, and the conductor 542 via the insulator 554. The insulator 580 is preferably made of, for example, silicon oxide, silicon oxynitride, silicon nitride, fluorine-added silicon oxide, carbon-added silicon oxide, carbon and nitrogen-added silicon oxide, or porous silicon oxide. Silicon oxide and silicon oxynitride are particularly preferred because they are thermally stable. Materials such as silicon oxide, silicon oxynitride, or porous silicon oxide are particularly preferred because they can easily form regions containing oxygen that is desorbed by heating.

[0444] It is preferable that the concentration of impurities such as water or hydrogen in the insulator 580 is reduced. Furthermore, the upper surface of the insulator 580 may be flattened.

[0445] The insulator 574 preferably functions as a barrier insulating film that suppresses the incorporation of impurities such as water or hydrogen into the insulator 580 from above, similar to the insulator 514, for example. For the insulator 574, any insulator that can be used for insulator 514 or insulator 554, for example, may be used.

[0446] It is preferable to provide an insulator 581, which functions as an interlayer film, on top of the insulator 574. It is preferable that the insulator 581, like the insulator 524, has a reduced concentration of impurities such as water or hydrogen in the film.

[0447] Conductors 545a and 545b are placed in the openings formed in insulators 581, 574, 580, and 554. Conductors 545a and 545b are provided facing each other with conductor 560 in between. The height of the upper surfaces of conductors 545a and 545b may be on the same plane as the upper surface of insulator 581.

[0448] Furthermore, an insulator 541a is provided in contact with the inner wall of the opening of insulators 581, 574, 580, and 554, and a first conductive portion of conductor 545a is formed in contact with its side surface. Conductor 542a is located in at least a portion of the bottom of the opening, and conductor 545a is in contact with conductor 542a. Similarly, an insulator 541b is provided in contact with the inner wall of the opening of insulators 581, 574, 580, and 554, and a first conductive portion of conductor 545b is formed in contact with its side surface. Conductor 542b is located in at least a portion of the bottom of the opening, and conductor 545b is in contact with conductor 542b.

[0449] It is preferable that the conductors 545a and 545b are made of conductive materials mainly composed of tungsten, copper, or aluminum. Furthermore, the conductors 545a and 545b may be arranged in a laminated structure.

[0450] When the conductor 545 has a laminated structure, it is preferable to use a conductor that has the function of suppressing the diffusion of impurities such as water or hydrogen, as described above, for the conductors in contact with the conductor 542, insulator 554, insulator 580, insulator 574, and insulator 581. For example, it is preferable to use tantalum, tantalum nitride, titanium, titanium nitride, ruthenium, or ruthenium oxide. Furthermore, the conductive material that has the function of suppressing the diffusion of impurities such as water or hydrogen may be used in a single layer or a laminate. By using such a conductive material, it is possible to suppress the absorption of oxygen added to the insulator 580 by the conductors 545a and 545b. In addition, it is possible to suppress the mixing of impurities such as water or hydrogen from the layer above the insulator 581 into the metal oxide 531 through the conductors 545a and 545b.

[0451] For insulators 541a and 541b, any insulator that can be used for insulator 554, for example, may be used. Since insulators 541a and 541b are provided in contact with insulator 554, it is possible to suppress the mixing of impurities such as water or hydrogen from insulator 580, for example, into the metal oxide 531 through conductors 545a and 545b. Furthermore, it is possible to suppress the absorption of oxygen contained in insulator 580 into conductors 545a and 545b.

[0452] Although not shown in the figures, conductors that function as wiring may be placed in contact with the upper surfaces of conductor 545a and conductor 545b. The conductors that function as wiring are preferably made of a conductive material mainly composed of tungsten, copper, or aluminum. The conductors may also be in a laminated structure, for example, a laminate of titanium or titanium nitride and the conductive material. The conductors may be formed to be embedded in an opening provided in the insulator.

[0453] <Materials that make up a transistor> This section describes the constituent materials that can be used in transistors.

[0454] [substrate] As a substrate for forming the transistor 500, for example, an insulating substrate, a semiconductor substrate, or a conductive substrate may be used. Examples of insulating substrates include glass substrates, quartz substrates, sapphire substrates, stabilized zirconia substrates (e.g., yttria-stabilized zirconia substrates), or resin substrates. Examples of semiconductor substrates include silicon or germanium semiconductor substrates, or compound semiconductor substrates made of silicon carbide, silicon germanium, gallium arsenide, indium phosphide, zinc oxide, or gallium oxide. Furthermore, there are semiconductor substrates having insulating regions within the aforementioned semiconductor substrates, such as SOI (Silicon On Insulator) substrates. Examples of conductive substrates include graphite substrates, metal substrates, alloy substrates, or conductive resin substrates. Alternatively, for example, there are substrates having metal nitrides or metal oxides. Furthermore, there are substrates in which a conductor or semiconductor is provided on an insulating substrate, substrates in which a conductor or insulator is provided on a semiconductor substrate, or substrates in which a semiconductor or insulator is provided on a conductive substrate, and so on. Alternatively, substrates on which elements are provided may be used. Examples of elements provided on the substrate include capacitive elements, resistive elements, switch elements, light-emitting elements, or memory elements.

[0455] [Insulator] Examples of insulators include insulating oxides, nitrides, oxidized nitrides, nitride oxides, metal oxides, metal oxidized nitrides, or metal nitride oxides.

[0456] For example, as transistors become smaller and more integrated, the thinning of the gate insulator can lead to problems such as leakage current. By using a high-k material for the insulator that functions as the gate insulator, it is possible to lower the voltage during transistor operation while maintaining the physical film thickness. On the other hand, by using a material with a low dielectric constant for the insulator that functions as the interlayer film, parasitic capacitance between wiring can be reduced. Therefore, it is best to select the material according to the function of the insulator.

[0457] Examples of insulators with high dielectric constants include gallium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium, oxide nitrides containing aluminum and hafnium, oxides containing silicon and hafnium, oxide nitrides containing silicon and hafnium, or nitrides containing silicon and hafnium.

[0458] Examples of insulators with low dielectric constants include silicon oxide, silicon oxide nitride, silicon oxide nitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, silicon oxide with vacancies, or resins.

[0459] Transistors using oxide semiconductors can have their electrical characteristics stabilized by surrounding them with an insulator that has the function of suppressing the permeation of impurities such as hydrogen and oxygen (for example, insulators 514, 522, 554, and 574). For example, as an insulator that has the function of suppressing the permeation of impurities such as hydrogen and oxygen, an insulator containing boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum, neodymium, hafnium, or tantalum can be used in a single layer or multilayer configuration. Specifically, as an insulator that has the function of suppressing the permeation of impurities such as hydrogen and oxygen, for example, metal oxides such as aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, or tantalum oxide can be used, or metal nitrides such as aluminum nitride, titanium aluminum nitride, titanium nitride, silicon oxide nitride, or silicon nitride.

[0460] The insulator that functions as a gate insulator is preferably an insulator that has a region containing oxygen that is desorbed by heating. For example, by having a structure in which silicon oxide or silicon oxynitride having a region containing oxygen that is desorbed by heating is in contact with the metal oxide 531, the oxygen deficiency of the metal oxide 531 can be compensated for.

[0461] [conductor] As a conductor, it is preferable to use a metallic element selected from, for example, 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 composed of the above metallic elements, or an alloy combining the above metallic elements. For example, it is preferable to use tantalum nitride, titanium nitride, tungsten, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, or oxides containing lanthanum and nickel. Furthermore, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, or oxides containing lanthanum and nickel are preferred because they are conductive materials that are resistant to oxidation or maintain conductivity even when absorbing oxygen. Alternatively, semiconductors with high electrical conductivity, such as polycrystalline silicon containing impurity elements like phosphorus, or silicides such as nickel silicide may be used.

[0462] Multiple conductors formed from the above materials may be used in a laminated structure. For example, a laminated structure may be formed by combining a material containing the aforementioned metal element with a conductive material containing oxygen. Alternatively, a laminated structure may be formed by combining a material containing the aforementioned metal element with a conductive material containing nitrogen. Furthermore, a laminated structure may be formed by combining a material containing the aforementioned metal element with a conductive material containing oxygen and a conductive material containing nitrogen.

[0463] Furthermore, when using a metal oxide for the channel formation region of a transistor, it is preferable to use a laminated structure for the conductor functioning as the gate electrode, which combines a material containing the aforementioned metal element with a conductive material containing oxygen. In this case, it is preferable to place the conductive material containing oxygen on the channel formation region side. By placing the conductive material containing oxygen on the channel formation region side, oxygen released from the conductive material is more easily supplied to the channel formation region.

[0464] In particular, it is preferable to use a conductive material containing a metal element and oxygen in the metal oxide in which the channel is formed as the conductor that functions as the 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. In addition, indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, or silicon-doped indium tin oxide may be used. In addition, indium gallium zinc oxide containing nitrogen may be used. By using such materials, it may be possible to capture hydrogen contained in the metal oxide in which the channel is formed. Alternatively, it may be possible to capture hydrogen that is mixed in from, for example, an external insulator.

[0465] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0466] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

[0467] (Embodiment 5) This embodiment describes metal oxides (hereinafter also referred to as oxide semiconductors) that can be used in the OS transistor described in the above embodiment.

[0468] The metal oxide used in the OS transistor preferably contains at least indium or zinc, and more preferably indium and zinc. For example, the metal oxide preferably contains indium, M (where 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] Metal oxides can be formed, for example, by chemical vapor deposition (CVD) methods such as sputtering or metal-organic chemical vapor deposition (MOCVD), or by atomic layer deposition (ALD).

[0470] In the following sections, we will describe oxides containing indium (In), gallium (Ga), and zinc (Zn) as examples of metal oxides. Note that oxides containing indium (In), gallium (Ga), and zinc (Zn) are sometimes called In-Ga-Zn oxides.

[0471] <Classification of crystal structures> Examples of crystalline structures for oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystal.

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

[0473] For example, in a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, in an In-Ga-Zn oxide film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical shape of the XRD spectrum peaks 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 the diffraction pattern (also called the nano-beam electron diffraction pattern) observed by nano-beam 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. On the other hand, in the diffraction pattern of an In-Ga-Zn oxide film deposited at room temperature, a spot-like pattern is observed instead of a halo. Therefore, In-Ga-Zn oxide deposited at room temperature is in an intermediate state, neither single-crystal, polycrystalline, nor amorphous. For this reason, it is difficult to conclude that it is in an amorphous state.

[0475] [Structure of oxide semiconductors] It should be noted that oxide semiconductors may be classified differently from those described above when focusing on their structure. For example, oxide semiconductors can be divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the aforementioned CAAC-OS and nc-OS. Furthermore, non-single-crystal oxide semiconductors include, for example, polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0476] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0477] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, the c-axis of which is oriented in a specific direction. This specific direction is the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. If we consider the atomic arrangement as a lattice arrangement, then a crystalline region is also a region with a aligned lattice arrangement. Furthermore, CAAC-OS has regions where multiple crystalline regions are connected in the ab-plane direction, and these regions may exhibit distortion. Distortion refers to a point in the connected region where the orientation of the lattice arrangement changes between a region with a aligned lattice arrangement and another region with a aligned lattice arrangement. In short, CAAC-OS is an oxide semiconductor that is c-axis oriented and does not exhibit clear orientation in the ab-plane direction.

[0478] Each of the above-mentioned 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 that crystalline region is less than 10 nm. When a crystalline region is composed of multiple minute crystals, the maximum diameter of that crystalline region may be around several tens of nm.

[0479] Furthermore, in In-Ga-Zn oxides, CAAC-OS tends to have a layered crystalline structure (also called a layered structure) consisting of layers containing indium (In) and oxygen (hereinafter referred to as the In layer) and layers containing gallium (Ga), zinc (Zn), and oxygen (hereinafter referred to as the (Ga,Zn) layer). Note that indium and gallium are mutually substitutable. Therefore, the (Ga,Zn) layer may contain indium. Also, the In layer may contain gallium. Also, the In layer may contain zinc. This layered structure can be observed, for example, as a lattice image in high-resolution TEM (Transmission Electron Microscope) images.

[0480] When structural analysis of a CAAC-OS film is performed using, for example, an XRD instrument, out-of-plane XRD measurements using θ / 2θ scanning show a peak indicating c-axis orientation at 2θ = 31° or nearby. Note that the position of the peak indicating c-axis orientation (value of 2θ) may vary depending on, for example, the type of metal element or composition constituting the CAAC-OS.

[0481] Furthermore, for example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film. These spots are observed at point-symmetric positions with respect to the incident electron beam spot (also called the direct spot) that passed through the sample.

[0482] When observing the crystal region from the specific direction described above, the lattice arrangement within that crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, in the strained region, the lattice arrangement may be, for example, pentagonal or heptagonal. Moreover, in CAAC-OS, it is difficult to confirm clear grain boundaries even near the strain. In other words, it can be seen that the formation of grain boundaries is suppressed by the strain in the lattice arrangement. This may be because CAAC-OS can tolerate strain due to, for example, the sparse arrangement of oxygen atoms in the ab-plane direction, and the change in interatomic bond distances due to the substitution of metal atoms.

[0483] Furthermore, a crystal structure in which clear grain boundaries can be observed is called a polycrystalline material. Grain boundaries act as recombination centers, trapping carriers and potentially causing, for example, a decrease in the on-current of a transistor and a decrease in field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries cannot be observed, is one of the crystalline oxides with a crystal structure suitable for the semiconductor layer of a transistor. In addition, a structure containing Zn is preferred for the composition of CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are preferred 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 clearly defined grain boundaries. Therefore, CAAC-OS is less susceptible to the decrease in electron mobility caused by grain boundaries. Furthermore, since the crystallinity of oxide semiconductors can decrease due to impurities or defects, CAAC-OS can be considered an oxide semiconductor with few impurities and defects (e.g., oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat-resistant and highly reliable. In addition, CAAC-OS is stable even at high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using CAAC-OS in OS transistors allows for greater flexibility in the manufacturing process.

[0485] [nc-OS] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions between 1 nm and 10 nm, particularly between 1 nm and 3 nm). In other words, nc-OS contains minute crystals. These minute crystals are also called nanocrystals because their size is, for example, between 1 nm and 10 nm, particularly between 1 nm and 3 nm. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Consequently, depending on the analytical method, nc-OS may be indistinguishable from a-like OS and amorphous oxide semiconductors. For example, when structural analysis of an nc-OS film is performed using an XRD instrument, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Also, when electron diffraction (also called limited-field electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of the nanocrystals (e.g., 50 nm or larger), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystal (for example, 1 nm to 30 nm), an electron diffraction pattern may be obtained in which multiple spots are observed within a ring-shaped region centered on a direct spot.

[0486] [a-like OS] a-like OS is an oxide semiconductor having a structure between nc-OS and amorphous oxide semiconductors. a-like OS has porous or low-density regions. OS has lower crystallinity compared to nc-OS and CAAC-OS. Also, a-like OS has a higher hydrogen concentration in the membrane compared to nc-OS and CAAC-OS.

[0487] [Oxide semiconductor configuration] Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0488] [CAC-OS] CAC-OS is a material composition in which, for example, the elements constituting the metal oxide are unevenly distributed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size. In the following, a state in which one or more metal elements are unevenly distributed in a metal oxide, and the regions containing these metal elements are mixed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size, is also referred to as a mosaic or patchy pattern.

[0489] Furthermore, CAC-OS is a composite metal oxide having a mosaic-like structure formed by the separation of the material into a first region and a second region, with the first region distributed within the film (hereinafter also referred to as a cloud-like structure). In other words, 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 In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS of In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. The second region is the region where [Ga] is greater than the [Ga] in the first region, and [In] is smaller than the [In] in the first region.

[0491] Specifically, the first region described above is a region whose main component is, for example, indium oxide or indium zinc oxide. The second region described above 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] Furthermore, it may be difficult to observe a clear boundary between the first region and the second region described above.

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

[0494] CAC-OS can be formed, for example, by sputtering under conditions where the substrate is not intentionally heated. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. Furthermore, a lower ratio of the oxygen gas flow rate to the total deposition gas flow rate during deposition is preferable. For example, the ratio of the oxygen gas flow rate to the total deposition gas flow rate during deposition should be 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 In-Ga-Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) confirms that it has a structure in which regions mainly composed of In (first region) and regions mainly composed of Ga (second region) are unevenly distributed and mixed.

[0496] Here, the first region is a region with higher conductivity compared to the second region. In other words, the conductivity of the metal oxide is exhibited when carriers flow through the first region. Therefore, a high field-effect mobility (μ) can be achieved when the first region is distributed in a cloud-like manner within the metal oxide.

[0497] On the other hand, the second region is a region with higher insulating properties compared to the first region. In other words, the distribution of the second region within the metal oxide can suppress leakage current.

[0498] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulation due to the second region work complementaryly to give CAC-OS a switching function (the function of putting it into an on or off state). In other words, CAC-OS has conductive function in part of the material, insulating function in part of the material, and semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using CAC-OS in a transistor, a high on-current (I on This enables high field-effect mobility (μ) and good switching operation.

[0499] Furthermore, transistors using CAC-OS offer high reliability. Therefore, CAC-OS is ideal for various semiconductor devices, including display devices.

[0500] Oxide semiconductors can take on diverse structures, each possessing different properties. An oxide semiconductor according to one aspect of the present invention may comprise two or more of amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0501] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0502] By using the above-mentioned oxide semiconductor in transistors, it is possible to realize transistors with high field-effect mobility. Furthermore, it is possible to realize highly reliable transistors.

[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] It is preferable to use an oxide semiconductor with a low carrier concentration for the transistor. For example, the carrier concentration of an oxide semiconductor is 1 × 10⁻⁶. 17 cm -3 The following is preferably 1 × 10 15 cm -3 More preferably 1 × 10 13 cm -3 More preferably 1 × 10 11 cm -3 More preferably 1 × 10 10 cm -3 It is less than 1 × 10 -9 cm -3 This concludes the explanation. Furthermore, to lower the carrier concentration in an oxide semiconductor, the defect level density in the oxide semiconductor can be reduced by lowering the impurity concentration in the oxide semiconductor. In this specification, a low impurity concentration and low defect level density are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that an oxide semiconductor with a low carrier concentration may be referred to as a high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor.

[0505] High-purity intrinsic or substantially high-purity intrinsic oxide semiconductors have a low defect level density, which may result in a low trap level density.

[0506] Charges trapped in the trap levels of oxide semiconductors can take a long time to disappear and sometimes behave like fixed charges. Therefore, transistors in which channel formation regions are formed in oxide semiconductors with a high density of trap levels may exhibit unstable electrical properties.

[0507] Therefore, reducing the impurity concentration in the oxide semiconductor is effective in 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, or silicon. Note that impurities in an oxide semiconductor refer to elements other than the main components that make up the oxide semiconductor. For example, elements with a concentration of less than 0.1 atomic percent can be considered impurities.

[0508] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0509] In oxide semiconductors, the presence of silicon or carbon, which are Group 14 elements, leads to the formation of defect levels in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor (Secondary Ion Mass Spectrometry (SIMS)) The concentration obtained by spectrometry is 2 × 10 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0510] When alkali metals or alkaline earth metals are present in oxide semiconductors, they can form defect levels and generate carriers. Therefore, transistors using oxide semiconductors containing alkali metals or alkaline earth metals tend to exhibit normally-on characteristics. For this reason, the concentration of alkali metals or alkaline earth metals in the oxide semiconductor obtained by SIMS should be set to 1 × 10⁻⁶. 18 atoms / cm 3The following is preferably 2 × 10 16 atoms / cm 3 Do the following:

[0511] In oxide semiconductors, the presence of nitrogen generates electrons, which act as carriers, increasing the carrier concentration and making it easier for the semiconductor to become n-type. As a result, transistors using oxide semiconductors containing nitrogen tend to exhibit normally-on characteristics. Alternatively, the presence of nitrogen in oxide semiconductors can lead to the formation of trap levels. This can result in unstable electrical properties of the transistor. Therefore, the nitrogen concentration in oxide semiconductors obtained by SIMS should be set to 5 × 10⁻¹⁰. 19 atoms / cm 3 Less than 5 × 10 18 atoms / cm 3 More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0512] Hydrogen contained in oxide semiconductors can react with oxygen bonded to metal atoms to form water, potentially creating oxygen vacancies. When hydrogen fills these vacancies, electrons, which act as carriers, can be generated. Furthermore, some of the hydrogen can combine with oxygen bonded to metal atoms to generate electrons. Therefore, transistors using oxide semiconductors containing hydrogen tend to exhibit normally-on characteristics. For this reason, it is preferable to reduce the hydrogen content in oxide semiconductors as much as possible. Specifically, the hydrogen concentration in the oxide semiconductor obtained by SIMS should be 1 × 10⁻⁶. 20 atoms / cm 3 Less than 1 × 10 19 atoms / cm 3 Less than 5x10 18 atoms / cm 3 Less than 1 × 10 18 atoms / cm 3 Make it less than.

[0513] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be provided.

[0514] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments. [Explanation of Symbols]

[0515] 10: Display device, 11: Light source, 12: Optical system, 13: Optical device, 14: Housing, 14a: Aperture, 14b: Aperture, 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: Photodetector, 70: Display device, 80: Pixel, 95: Display area, 100: Electronic device, 101: Housing, 103: Mounted 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: Eye 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 area, 293: Peripheral circuit area, 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: Photodetector, 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: Photodetector, 493: Transistor, 494: Transistor, 495 :Wiring, 496:Transistor, 497:Wiring, 498:Transistor, 499:Wiring, 500:Transistor, DL_n:Signal line, GL_m:Scan 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:Point of focus, S1:Region, S2:Region, S3:Region, S210:Step, S211:Step, S212:Step, S213:Step, S214:Step

Claims

1. A device comprising a display device and an optical system, The display device comprises a display area and a sensor area. The optical system comprises a first mirror and a second mirror, The first mirror comprises a first surface and a second surface, The aforementioned display area is equipped with a function for emitting first light, The first mirror is provided on the optical path of the first light and has the function of transmitting the first light incident on the first surface to the second surface, and the function of reflecting the second light incident on the second surface. The second mirror is provided on the optical path of the second light and has the function of reflecting the second light. The sensor region has the function of detecting the second light that is incident after being reflected in the order of the first mirror and the second mirror. The second light is reflected light from the object to which the third light was irradiated. The third light mentioned above is emitted from the light source. optical equipment.

2. In claim 1, The display device comprises the light source, optical equipment.

3. In claim 1 or claim 2, The third light is infrared light. optical equipment.

4. In claim 1 or claim 2, The sensor area is provided overlapping with the display area. optical equipment.

5. In claim 1 or claim 2, The optical system comprises a first lens, The first lens is provided on the optical path of the first light and has a function to control the optical path of the first light. optical equipment.

6. In claim 1 or claim 2, The display device comprises a second lens, The second lens is provided between the second mirror and the sensor region and has a function of controlling the optical path of the second light. optical equipment.

7. In claim 1 or claim 2, The aforementioned display device is equipped with a pinhole, The pinhole is provided between the second mirror and the sensor region, and has the function of controlling the optical path of the second light. optical equipment.

8. In claim 1 or claim 2, The display device includes a gaze detection unit, The gaze detection unit has a function to detect the user's gaze using the image data acquired in the sensor area. optical equipment.

Images