Correction method for display device

Abstract

Provided is a new correction method for a display device. One aspect of the present invention is a correction method for a display device, the correction method involving: performing a process in which the voltage for correcting the threshold voltage of a transistor is acquired and the voltage is maintained at a capacity; in a first circuit, performing a process in which electric current flowing to a pixel is measured and a second signal based on the electric current is generated; in a second circuit, performing a process in which a first signal obtained by correcting image data is generated by using the second signal; and performing a process in which the first signal is supplied to the pixel.

Description

Display device correction method

[0001] One embodiment of the present invention relates to a method for correcting a display device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention disclosed in this specification and the like include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device, an input / output device, a driving method thereof, or a manufacturing method thereof.

[0003] In this specification, a semiconductor device is a device that utilizes semiconductor characteristics, and refers to a circuit including a semiconductor element (transistor, diode, photodiode, etc.), a device having such a circuit, etc. It also refers to any device that can function by utilizing semiconductor characteristics. For example, an integrated circuit, a chip including an integrated circuit, and an electronic component that houses a chip in a package are examples of semiconductor devices. Furthermore, memory devices, display devices, light-emitting devices, lighting devices, electronic devices, etc. may themselves be semiconductor devices and may also include semiconductor devices.

[0004] In recent years, electronic devices equipped with display devices, such as smartphones and tablet terminals, have become widespread. Typical examples of display devices include liquid crystal display devices, organic electroluminescence (EL) elements, light-emitting devices equipped with light-emitting elements such as light-emitting diodes (LEDs), and electronic paper that displays images using an electrophoretic method.

[0005] For example, the basic structure of an organic EL element is a layer containing a light-emitting organic compound sandwiched between a pair of electrodes. By applying a voltage to this element, light can be emitted from the light-emitting organic compound. A display device using such an organic EL element does not require a backlight, which is necessary in liquid crystal display devices and the like, and therefore can realize a thin, lightweight, high-contrast, and low-power display device. Furthermore, since the response speed of organic EL elements is fast, a display device suitable for displaying fast-moving images can be realized. For example, an example of a display device using an organic EL element is described in Patent Document 1.

[0006] Furthermore, Patent Document 2 discloses a circuit configuration that corrects variations in threshold voltage of transistors for each pixel in a pixel circuit that controls the light emission brightness of an organic EL element, thereby improving the display quality of a display device.

[0007] JP 2002-324673 A JP 2015-132816 A

[0008] On the other hand, variations in the characteristics of organic EL elements from pixel to pixel can cause display unevenness. Furthermore, moisture, oxygen, light, and heat can accelerate the degradation of organic EL element characteristics, resulting in a decrease in brightness. Furthermore, the rate at which organic EL element characteristics deteriorate depends on factors such as the device structure, material characteristics, manufacturing process conditions, and display device driving method. For example, in a color display system using three types of organic EL elements corresponding to R (red), G (green), and B (blue), the organic EL elements may deteriorate at different rates for each corresponding color. In this case, the brightness of the organic EL elements varies over time, resulting in a problem in which the display device cannot display the desired color.

[0009] An object of one embodiment of the present invention is to provide a display device with improved display quality, a novel display device, or a novel correction method for a display device.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description of the specification, drawings, claims, etc.

[0011] (1) One aspect of the present invention is a method for correcting a display device including a pixel, a first circuit, and a second circuit, wherein the pixel includes a light-emitting element, a transistor, and a capacitor, and the transistor has a function of controlling a current supplied to the light-emitting element based on a first signal supplied to the pixel. The method for correcting a display device includes: performing a first process of acquiring a voltage for correcting a threshold voltage of the transistor and storing the voltage in the capacitor; measuring a current flowing through the pixel in the first circuit after the first process is completed and generating a second signal based on the measured current; performing a second process; generating a first signal by correcting image data using the second signal in the second circuit after the second process is completed; performing a third process; and supplying the first signal to the pixel after the third process is completed.

[0012] (2) One aspect of the present invention is a method for correcting a display device including a pixel, a first circuit, and a second circuit, wherein the pixel includes a light-emitting element, a transistor, and a capacitor, and the transistor has a function of controlling a current supplied to the light-emitting element based on a first signal supplied to the pixel, the method comprising: measuring a current flowing through the pixel in the first circuit and generating a second signal based on the current; performing a second process; obtaining a voltage for correcting a threshold voltage of the transistor after the second process is completed and storing the voltage in the capacitor; performing the first process; after the second process is completed, generating a first signal by correcting image data using the second signal in the second circuit; performing a third process; and supplying the first signal to the pixel after the first process and the third process are completed.

[0013] (3) In the above (2), the first process and the third process may be carried out simultaneously.

[0014] (4) In any one of (1) to (3) above, the second process may measure a current flowing through the light-emitting element.

[0015] (5) In any one of (1) to (4), the transistor may include a back gate, the transistor may have a function of controlling a threshold voltage of the transistor based on a potential supplied to the back gate, and the first process may obtain a voltage between the back gate and a source of the transistor.

[0016] (6) In any one of (1) to (5) above, the fourth process may supply the first signal to a gate of the transistor.

[0017] According to one embodiment of the present invention, a display device with improved display quality can be provided, or a novel display device can be provided, or a novel method for correcting a display device can be provided.

[0018] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these can be extracted from the description in the specification, drawings, claims, etc.

[0019] FIG. 1 is a diagram illustrating an example of a display device. FIG. 2 is a diagram illustrating an example of a display device. FIG. 3 is a diagram illustrating an example of a display device. FIGS. 4A to 4C are diagrams illustrating circuit symbols of transistors. FIG. 5 is a flowchart illustrating an example of a correction method for a display device. FIG. 6 is a timing chart illustrating an example of the operation of a display device. FIG. 7 is a diagram illustrating an example of the operation of a display device. FIG. 8 is a diagram illustrating an example of the operation of a display device. FIG. 9 is a diagram illustrating an example of the operation of a display device. FIG. 10 is a diagram illustrating an example of the operation of a display device. FIG. 11 is a diagram illustrating an example of the operation of a display device. FIG. 12 is a diagram illustrating an example of the operation of a display device. FIG. 13 is a diagram illustrating an example of the operation of a display device. FIG. 14 is a flowchart illustrating an example of a correction method for a display device. FIG. 15 is a diagram illustrating an example of a specific configuration of a display device. FIGS. 16A to 16C are diagrams illustrating an example of the configuration of a display device. FIGS. 17A to 17F are diagrams illustrating an example of the configuration of a pixel. FIG. 18 is a diagram illustrating an example of the configuration of a display device. FIGS. 19A and 19B are diagrams illustrating an example of the configuration of a display device. FIGS. 20A to 20F are diagrams illustrating an example of the configuration of a light-emitting device. 21A to 21F are diagrams illustrating an example of an electronic device. FIGS. 22A to 22F are diagrams illustrating an example of an electronic device. FIGS. 23A and 23B are diagrams illustrating an example of an electronic device. FIG. 24 is a diagram illustrating an example of an electronic device.

[0020] Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments can be implemented in many different ways. Therefore, it will be readily understood by those skilled in the art that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the following embodiments.

[0021] Furthermore, when it is stated in this specification that X and Y are connected, it is understood that the following cases are disclosed in this specification: when X and Y are electrically connected, when X and Y are functionally connected, and when X and Y are directly connected. Therefore, it is not limited to a specific connection relationship, for example, a connection relationship shown in a figure or text, and it is understood that connections other than those shown in a figure or text are also disclosed in a figure or text. X and Y are understood to be objects (e.g., devices, elements, circuits, wiring, electrodes, terminals, conductive films, layers, etc.).

[0022] As an example of the case where X and Y are electrically connected, one or more elements (e.g., switches, transistors, capacitance elements, inductors, resistance elements, diodes, display devices, light-emitting devices, loads, etc.) that enable the electrical connection between X and Y can be connected between X and Y.

[0023] As an example of a case where X and Y are functionally connected, one or more circuits that enable the functional connection between X and Y (for example, logic circuits (inverters, NAND circuits, NOR circuits, etc.), signal conversion circuits (digital-analog conversion circuits, analog-digital conversion circuits, gamma correction circuits, etc.), potential level conversion circuits (power supply circuits (boosting circuits, step-down circuits, etc.), level shifter circuits that change the potential level of a signal, etc.), voltage sources, current sources, switching circuits, amplifier circuits (circuits that can increase the signal amplitude or amount of current, operational amplifiers, differential amplifier circuits, source follower circuits, buffer circuits, etc.), signal generation circuits, memory circuits, control circuits, etc.) can be connected between X and Y. As an example, even if another circuit is sandwiched between X and Y, if a signal output from X is transmitted to Y, X and Y are considered to be functionally connected.

[0024] It should be noted that when it is explicitly stated that X and Y are electrically connected, this includes the case where X and Y are electrically connected (i.e., the case where X and Y are connected with another element or another circuit sandwiched between them) and the case where X and Y are directly connected (i.e., the case where X and Y are connected without another element or another circuit sandwiched between them).

[0025] Furthermore, for example, it can be expressed as follows: "X, Y, and the source (or first terminal, etc.) and drain (or second terminal, etc.) of the transistor are electrically connected to each other, and are electrically connected in the order of X, the source (or first terminal, etc.) of the transistor, the drain (or second terminal, etc.) of the transistor, and Y." Or, it can be expressed as follows: "The source (or first terminal, etc.) of the transistor is electrically connected to X, and the drain (or second terminal, etc.) of the transistor is electrically connected to Y, and X, the source (or first terminal, etc.) of the transistor, the drain (or second terminal, etc.) of the transistor, and Y are electrically connected in this order." Or, it can be expressed as follows: "X is electrically connected to Y via the source (or first terminal, etc.) and drain (or second terminal, etc.) of the transistor, and X, the source (or first terminal, etc.) of the transistor, the drain (or second terminal, etc.) of the transistor, and Y are provided in this connection order." By using expressions similar to these examples to define the order of connections in a circuit configuration, the source (or first terminal, etc.) and drain (or second terminal, etc.) of a transistor can be distinguished and the technical scope can be determined. Note that these expressions are merely examples and are not limiting. Here, X and Y represent objects (e.g., devices, elements, circuits, wiring, electrodes, terminals, conductive films, layers, etc.).

[0026] Note that even when independent components are shown electrically connected in a circuit diagram, one component may have the functions of multiple components. For example, if part of a wiring also functions as an electrode, one conductive film has the functions of both components: the wiring function and the electrode function. Therefore, in this specification, the term "electrically connected" also includes such cases where one conductive film has the functions of multiple components.

[0027] Furthermore, in this specification, the term "capacitive element" can refer to, for example, a circuit element having a capacitance value higher than 0 F, a region of wiring having a capacitance value higher than 0 F, parasitic capacitance, or the gate capacitance of a transistor. Therefore, in this specification, the term "capacitive element" includes not only a circuit element including a pair of electrodes and a dielectric between the electrodes, but also parasitic capacitance occurring between wiring and one of the source or drain of a transistor and the gate, and the like. Furthermore, terms such as "capacitive element," "parasitic capacitance," and "gate capacitance" can be replaced with terms such as "capacitance," and conversely, the term "capacitance" can be replaced with terms such as "capacitive element," "parasitic capacitance," and "gate capacitance." Furthermore, the term "pair of electrodes" in "capacitance" can be replaced with "pair of conductors," "pair of conductive regions," "pair of regions," and the like. The capacitance value can be, for example, 0.05 fF or more and 10 pF or less. It may also be, for example, 1 pF or more and 10 μF or less.

[0028] Furthermore, in this specification, a transistor has three terminals called a gate, a source, and a drain. The gate is a control terminal that controls the amount of current flowing between the source and the drain. The two terminals that function as a source or a drain are the input / output terminals of the transistor. One of the two input / output terminals becomes a source and the other becomes a drain depending on the transistor's conductivity type (n-channel or p-channel) and the level of the potential applied to the three terminals of the transistor. Therefore, in this specification, the terms source and drain are interchangeable. Furthermore, in this specification, when describing the connection relationship of a transistor, the terms "one of the source or drain" (or first electrode or first terminal) and "the other of the source or drain" (or second electrode or second terminal) are used. Note that, depending on the transistor structure, a backgate may be included in addition to the three terminals described above. In this case, in this specification, one of the gate or backgate of the transistor may be referred to as the first gate, and the other of the gate or backgate of the transistor may be referred to as the second gate. Furthermore, for the same transistor, the terms "gate" and "backgate" may be interchangeable. Furthermore, when a transistor has three or more gates, the gates may be referred to as a first gate, a second gate, a third gate, and so on in this specification.

[0029] Furthermore, in this specification and the like, the term "node" can be rephrased as a terminal, wiring, electrode, conductive layer, conductor, impurity region, etc., depending on the circuit configuration, device structure, etc. Furthermore, the term "node" can be rephrased as a terminal, wiring, etc.

[0030] Furthermore, in this specification, the ordinal numbers "first," "second," and "third" are used to avoid confusion between components. Therefore, they do not limit the number of components. Furthermore, they do not limit the order of the components. For example, a component referred to as "first" in one embodiment of this specification may be a component referred to as "second" in another embodiment, in the claims, etc. Furthermore, for example, a component referred to as "first" in one embodiment of this specification, etc. may be omitted in another embodiment, in the claims, etc.

[0031] Furthermore, in this specification, terms indicating position, such as "above," "below," "upward," or "belowward," may be used for convenience in describing the positional relationship between components with reference to the drawings. Furthermore, the positional relationship between components changes as appropriate depending on the direction in which each configuration is depicted. Therefore, the terms are not limited to those described in the specification, and can be rephrased appropriately depending on the situation. For example, the expression "insulator located on the upper surface of a conductor" can be rephrased as "insulator located on the lower surface of a conductor" by rotating the orientation of the drawing 180 degrees.

[0032] Furthermore, the terms "above" and "below" do not limit the positional relationship of components to being directly above or below and in direct contact with each other. For example, the expression "electrode B on insulating layer A" does not require that electrode B be formed on insulating layer A in direct contact with it, and does not exclude the inclusion of other components between insulating layer A and electrode B.

[0033] Furthermore, in this specification and the like, the term "overlap" does not limit the state of the stacking order of components, etc. For example, the expression "electrode B overlapping insulating layer A" does not limit the state in which electrode B is formed on insulating layer A, but does not exclude the state in which electrode B is formed under insulating layer A or the state in which electrode B is formed on the right (or left) side of insulating layer A, etc.

[0034] Furthermore, in this specification and the like, the terms "adjacent" and "close to" do not necessarily mean that components are in direct contact with each other. For example, the expression "electrode B adjacent to insulating layer A" does not require that insulating layer A and electrode B are formed in direct contact with each other, and does not exclude the inclusion of other components between insulating layer A and electrode B.

[0035] Furthermore, in this specification and the like, terms such as "film" and "layer" can be interchanged depending on the situation. For example, the term "conductive layer" may be changed to the term "conductive film." Or, for example, the term "insulating film" may be changed to the term "insulating layer." Or, depending on the situation, terms such as "film" and "layer" may be replaced with other terms without using terms such as "film" and "layer." For example, the term "conductive layer" or "conductive film" may be changed to the term "conductor." Or, the term "conductor" may be changed to the term "conductive layer" or "conductive film." Or, for example, the term "insulating layer" or "insulating film" may be changed to the term "insulator." Or, the term "insulator" may be changed to the term "insulating layer" or "insulating film."

[0036] Furthermore, in this specification and the like, terms such as "electrode," "wiring," or "terminal" do not functionally limit these components. For example, an "electrode" may be used as part of a "wiring," and vice versa. Furthermore, the terms "electrode" or "wiring" include, for example, cases where multiple "electrodes" or "wirings" are integrally formed. Furthermore, for example, a "terminal" may be used as part of a "wiring" or "electrode," and vice versa. Furthermore, the term "terminal" includes, for example, cases where multiple "electrodes," "wirings," or "terminals" are integrally formed. Therefore, for example, an "electrode" can be part of a "wiring" or "terminal." Furthermore, for example, a "terminal" can be part of a "wiring" or "electrode." Furthermore, terms such as "electrode," "wiring," or "terminal" may be replaced with, for example, a term such as "region."

[0037] Furthermore, in this specification and the like, terms such as "wiring," "signal line," and "power line" may be interchangeable depending on the circumstances. For example, the term "wiring" may be changed to the term "signal line." For example, the term "wiring" may be changed to the term "power line." Vice versa, terms such as "signal line" and "power line" may be changed to the term "wiring." A term such as "power line" may be changed to the term "signal line." Vice versa, terms such as "signal line" may be changed to the term "power line." Furthermore, the term "potential" applied to a wiring may be changed to the term "signal" depending on the circumstances. Vice versa, terms such as "signal" may be changed to the term "potential."

[0038] In addition, in this specification, a "switch" has multiple terminals and has the function of switching (selecting) conduction or non-conduction between the terminals. For example, when a switch has two terminals and both terminals are conductive, the switch is said to be in a "conductive state" or "on state." When both terminals are non-conductive, the switch is said to be in a "non-conductive state" or "off state." Note that switching to either a conductive state or a non-conductive state, or maintaining either a conductive state or a non-conductive state, is sometimes referred to as "controlling the conductive state."

[0039] In other words, a switch is a device that has the function of controlling whether or not a current flows. Alternatively, a switch is a device that has the function of selecting and switching the path through which a current flows. As an example, an electrical switch, a mechanical switch, etc. can be used. In other words, a switch is not limited to a specific type as long as it can control a current.

[0040] Examples of switches include transistors (e.g., bipolar transistors, MOS transistors, etc.), diodes (e.g., PN diodes, PIN diodes, Schottky diodes, MIM (Metal Insulator Metal) diodes, MIS (Metal Insulator Semiconductor) diodes, diode-connected transistors, etc.), and logic circuits combining these. When a transistor is used as a switch, the "conductive state" or "on state" of the transistor refers to a state in which the source electrode and drain electrode of the transistor can be considered to be electrically short-circuited. Furthermore, the "non-conductive state" or "off state" of the transistor refers to a state in which the source electrode and drain electrode of the transistor can be considered to be electrically disconnected. When a transistor is operated simply as a switch, the polarity (conductivity type) of the transistor is not particularly limited.

[0041] An example of a mechanical switch is a switch that uses MEMS (microelectromechanical systems) technology. This switch has a mechanically movable electrode, and the movement of the electrode selects a conductive state or a non-conductive state.

[0042] In this specification, "parallel" refers to a state in which two straight lines are arranged at an angle of -10° or more and 10° or less. Therefore, it also includes cases where the angle is -5° or more and 5° or less. Furthermore, "substantially parallel" or "roughly parallel" refers to a state in which two straight lines are arranged at an angle of -30° or more and 30° or less. Furthermore, "perpendicular" refers to a state in which two straight lines are arranged at an angle of 80° or more and 100° or less. Therefore, it also includes cases where the angle is 85° or more and 95° or less. Furthermore, "substantially perpendicular" or "approximately perpendicular" refers to a state in which two straight lines are arranged at an angle of 60° or more and 120° or less.

[0043] In this specification and elsewhere, when referring to counting values ​​and measurement values, terms such as "identical," "same," "equal," or "uniform" (including synonyms thereof) are used, unless otherwise specified, and include an error of plus or minus 20%.

[0044] The embodiments described in this specification will be described with reference to the drawings. However, the embodiments can be implemented in many different ways. Therefore, those skilled in the art will readily understand that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments. Note that in the configuration of the invention of the embodiments, the same reference numerals are used in different drawings for the same parts or parts having similar functions, and repeated description may be omitted. Furthermore, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be assigned. Furthermore, to make the drawings easier to understand, the illustration of some components may be omitted in perspective views, top views, etc.

[0045] In addition, in the drawings and the like relating to this specification, the size, layer thickness, or region may be exaggerated for clarity. Therefore, the size or aspect ratio is not necessarily limited. Note that the drawings are schematic illustrations of ideal examples and are not limited to the shapes or values ​​shown in the drawings. For example, variations in signal, voltage, or current due to noise, or variations in signal, voltage, or current due to timing deviations, etc. may be included.

[0046] In addition, in drawings and the like relating to this specification, arrows indicating the X direction, Y direction, and Z direction may be used. In this specification and the like, the "X direction" refers to the direction along the X axis, and the forward direction and the reverse direction may not be distinguished unless explicitly stated. The same applies to the "Y direction" and the "Z direction." The X direction, Y direction, and Z direction are directions that intersect with each other. More specifically, the X direction, Y direction, and Z direction are directions that are perpendicular to each other. In this specification and the like, one of the X direction, Y direction, and Z direction may be referred to as the "first direction" or "first direction." The other may be referred to as the "second direction" or "second direction." The remaining one may be referred to as the "third direction" or "third direction."

[0047] In this specification, when the same symbol is used for multiple elements, and particularly when it is necessary to distinguish between them, an identifying symbol such as “A”, “b”, “_1”, "[n]”, or "[m, n]” may be added to the symbol.

[0048] Embodiment 1 In this embodiment, a structural example of a display device according to one embodiment of the present invention and a method for correcting the display device will be described.

[0049] 1 shows a structural example of a display device according to one embodiment of the present invention. The display device 10 includes a pixel 11, a monitor circuit 12, and an image processing circuit 13. The pixel 11 also includes a light-emitting element 61, transistors M1 to M6, and capacitors C1 and C2.

[0050] The monitor circuit 12 has a function of supplying an arbitrary potential to the wiring ML. The monitor circuit 12 also has a function of measuring a current flowing through the pixel 11 through the wiring ML. The monitor circuit 12 also has a function of generating arbitrary data based on the measured current. For example, data on current-voltage characteristics may be generated by acquiring, as the arbitrary data, multiple values ​​of an arbitrary potential supplied to the wiring ML and values ​​of a current flowing through the wiring ML at that time.

[0051] The image processing circuit 13 has a function of correcting image data by using the arbitrary data generated by the monitor circuit 12 and generating display data. Note that in this embodiment and the like, the display data refers to the corrected image data. The image processing circuit 13 also has a function of supplying the display data or an arbitrary potential to the wiring DL. For example, the arbitrary potential may be a potential that can turn off the transistor M2.

[0052] The gate of the transistor M1 is electrically connected to the wiring GLa. One of the source and the drain of the transistor M1 is electrically connected to the wiring DL. The other of the source and the drain of the transistor M1 is electrically connected to the gate of the transistor M2. The transistor M1 has a function of bringing the gate of the transistor M2 and the wiring DL into a conductive state or a non-conductive state.

[0053] The gate of the transistor M2 is electrically connected to one terminal of the capacitor C1. One of the source and the drain of the transistor M2 is electrically connected to the wiring 51. The other of the source and the drain of the transistor M2 is electrically connected to the other terminal of the capacitor C1. The transistor M2 also has a backgate. The backgate of the transistor M2 is electrically connected to one terminal of the capacitor C2. The other terminal of the capacitor C2 is electrically connected to the other of the source and the drain of the transistor M2.

[0054] The gate of the transistor M3 is electrically connected to the wiring GLb. One of the source and the drain of the transistor M3 is electrically connected to one terminal of the capacitor C1. The other of the source and the drain of the transistor M3 is electrically connected to the other terminal of the capacitor C1. The transistor M3 has a function of bringing the gate of the transistor M2 and the other of the source and the drain of the transistor M2 into a conductive state or a non-conductive state.

[0055] The gate of the transistor M4 is electrically connected to the wiring GLb. One of the source and the drain of the transistor M4 is electrically connected to the wiring 53. The other of the source and the drain of the transistor M4 is electrically connected to one terminal of the capacitor C2. The transistor M4 has a function of bringing the wiring 53 and the one terminal of the capacitor C2 into a conductive state or a non-conductive state.

[0056] The gate of the transistor M5 is electrically connected to the wiring GLc. One of the source and the drain of the transistor M5 is electrically connected to the other of the source and the drain of the transistor M2. The other of the source and the drain of the transistor M5 is electrically connected to one terminal (e.g., an anode terminal) of the light-emitting element 61. The transistor M5 has a function of bringing the other of the source and the drain of the transistor M2 and the one terminal of the light-emitting element 61 into a conductive state or a non-conductive state.

[0057] The gate of the transistor M6 is electrically connected to the wiring GLa. One of the source and the drain of the transistor M6 is electrically connected to the other of the source and the drain of the transistor M2. The other of the source and the drain of the transistor M6 is electrically connected to the wiring ML. The transistor M6 has a function of bringing the other of the source and the drain of the transistor M2 into a conductive state or a non-conductive state with the wiring ML.

[0058] The other terminal (for example, the cathode terminal) of the light emitting element 61 is electrically connected to the wiring 52 .

[0059] The light-emitting element 61 emits light with a light emission intensity according to the amount of current flowing through the light-emitting element 61. As the light-emitting element 61, various display elements can be used, such as an EL element (an EL element including an organic material and an inorganic material, an organic EL element, or an inorganic EL element), an LED (for example, a white LED, a red LED, a green LED, or a blue LED), a micro LED (for example, an LED with one side less than 0.1 mm), a QLED (Quantum-dot Light Emitting Diode), or an electron-emitting element.

[0060] The transistor M2 has a function of controlling the amount of current flowing through the light-emitting element 61. That is, the transistor M2 has a function of controlling the light-emitting intensity of the light-emitting element 61. Therefore, in this specification, the transistor M2 may be referred to as a "drive transistor."

[0061] In addition, the region where the other terminals of the capacitors C1 and C2, the other of the source or drain of the transistor M2, the other of the source or drain of the transistor M3, one of the source or drain of the transistor M5, and one of the source or drain of the transistor M6 are electrically connected to each other is also referred to as node ND1.

[0062] A region where one terminal of the capacitor C2, the back gate of the transistor M2, and the other of the source and the drain of the transistor M4 are electrically connected to each other is also referred to as a node ND2.

[0063] A region where the other of the source and the drain of the transistor M1, one of the source and the drain of the transistor M3, one terminal of the capacitor C1, and the gate of the transistor M2 are electrically connected to each other is also referred to as a node ND3.

[0064] The capacitor C1 has a function of holding the potential difference (voltage) between the other of the source or drain of the transistor M2 and the gate of the transistor M2 when the node ND3 is in a floating state, for example.

[0065] The capacitor C2 has a function of holding the potential difference (voltage) between the other of the source or drain of the transistor M2 and the back gate of the transistor M2 when the node ND2 is in a floating state, for example.

[0066] In this embodiment and the like, the transistors M1 to M6 are enhancement-type (normally-off) n-channel field-effect transistors unless otherwise specified, and therefore, their threshold voltages (also referred to as "Vth") are assumed to be greater than 0 V.

[0067] The pixel 11 according to one embodiment of the present invention can include transistors containing various semiconductors. For example, a transistor including a single crystal semiconductor, a polycrystalline semiconductor, a microcrystalline semiconductor, or an amorphous semiconductor in a channel formation region can be used. Furthermore, the semiconductor is not limited to a single element semiconductor (e.g., silicon (Si) or germanium (Ge)) whose main component is a single element. For example, a compound semiconductor (e.g., silicon germanium (SiGe) or gallium arsenide (GaAs)), an oxide semiconductor, or the like can also be used.

[0068] Although an example in which the display device 10 is formed using n-channel transistors is shown in this embodiment and the like, one embodiment of the present invention is not limited thereto. Some or all of the transistors forming the display device 10 may be p-channel transistors.

[0069] Furthermore, the pixel 11 according to one embodiment of the present invention can use transistors with various structures. For example, transistors with various structures such as a planar type, a fin type, a tri-gate type, a top-gate type, a bottom-gate type, or a dual-gate type (a structure in which gates are arranged above and below a channel) can be used. Furthermore, as the transistor according to one embodiment of the present invention, for example, a MOS transistor, a junction transistor, or a bipolar transistor can be used.

[0070] For example, an OS transistor (a transistor including an oxide semiconductor in a semiconductor layer in which a channel is formed) may be used as a transistor included in the pixel 11. An oxide semiconductor has a band gap of 2 eV or more and therefore has a significantly low off-state current. Therefore, it is preferable to use an OS transistor as a transistor that functions as a switch. For example, the transistor M1 and the transistors M3 to M6 can be OS transistors.

[0071] The off-state current of an OS transistor per 1 μm of channel width at room temperature is 1 aA (1×10 −１８ A) Below, 1zA (1×10 −２１ A) or less, or 1 yA (1 x 10 −２４ The off-state current value of a Si transistor (a transistor including silicon in a semiconductor layer in which a channel is formed) per 1 μm of channel width at room temperature can be 1 fA (1×10 −１５ A) More than 1pA (1×10 −１２ Therefore, it can be said that the off-state current of an OS transistor is about 10 orders of magnitude lower than that of a Si transistor.

[0072] When an OS transistor is used as a transistor constituting the pixel 11, charge written to each node can be retained for a long period of time. For example, when displaying a still image that does not require rewriting for each frame, the image display can be continued even if the operation of the peripheral driver circuit is stopped. Such a driving method of stopping the operation of the peripheral driver circuit while displaying a still image is also called "idling stop driving." By performing idling stop driving, the power consumption of the display device can be reduced.

[0073] Furthermore, the off-state current of an OS transistor hardly increases even in a high-temperature environment. Specifically, the off-state current of an OS transistor hardly increases even in an environmental temperature range of room temperature or higher and 200° C. or lower. Furthermore, the on-state current is unlikely to decrease even in a high-temperature environment. A display device including an OS transistor can operate stably and achieve high reliability even in a high-temperature environment.

[0074] In addition, an OS transistor has a high withstand voltage between its source and drain. By using an OS transistor as a transistor constituting the pixel 11, operation is stable even when there is a large potential difference (voltage) between the potential supplied to the wiring 51 (also referred to as an anode potential) and the potential supplied to the wiring 52 (also referred to as a cathode potential), thereby realizing a highly reliable display device. In particular, it is preferable to use an OS transistor as one or both of the transistors M2 and M5.

[0075] The semiconductor layer of the OS transistor preferably contains, for example, indium, M (M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

[0076] 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. 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.

[0077] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such an In-M-Zn oxide include a composition of In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:3:2 or thereabouts, In:M:Zn=1:3:4 or thereabouts, In:M:Zn=2:1:3 or thereabouts, In:M:Zn=3:1:2 or thereabouts, and In:M:Zn=4:2:3. or a composition in the vicinity thereof, In:M:Zn = 4:2:4.1 or a composition in the vicinity thereof, In:M:Zn = 5:1:3 or a composition in the vicinity thereof, In:M:Zn = 5:1:6 or a composition in the vicinity thereof, In:M:Zn = 5:1:7 or a composition in the vicinity thereof, In:M:Zn = 5:1:8 or a composition in the vicinity thereof, In:M:Zn = 6:1:6 or a composition in the vicinity thereof, or In:M:Zn = 5:2:5 or a composition in the vicinity thereof, etc. Note that a composition in the vicinity thereof includes a range of plus or minus 30% of the desired atomic ratio.

[0078] For example, when describing a composition having an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, this includes a case where, when the atomic ratio of In is 4, the atomic ratio of Ga is 1 or more and 3 or less, and the atomic ratio of Zn is 2 or more and 4 or less. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, this includes a case where, when the atomic ratio of In is 5, the atomic ratio of Ga is more than 0.1 and 2 or less, and the atomic ratio of Zn is 5 or more and 7 or less. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, this includes a case where, when the atomic ratio of In is 1, the atomic ratio of Ga is more than 0.1 and 2 or less, and the atomic ratio of Zn is more than 0.1 and 2 or less.

[0079] The pixel 11 may also be configured with multiple types of transistors using different semiconductor materials. For example, the pixel 11 may be configured with a transistor having low temperature polysilicon (LTPS) in a semiconductor layer (hereinafter also referred to as an LTPS transistor) and an OS transistor. The LTPS transistor has high field-effect mobility and favorable frequency characteristics. A configuration in which an LTPS transistor and an OS transistor are combined may be referred to as LTPO.

[0080] For example, among the transistors included in the pixel 11, it is preferable to use OS transistors for the transistors M1 and M3 to M6 and an LTPS transistor for the transistor M2. In other words, it is preferable to use an OS transistor as a transistor that functions as a switch for controlling the conduction state or non-conduction state between wirings and an LTPS transistor as a transistor for controlling current. By using both an LTPO transistor, that is, an LTPS transistor and an OS transistor, in the pixel 11, a display device with low power consumption and high driving capability can be realized. As described above, the correction method for a display device according to one embodiment of the present invention is not limited to the structure of the transistor and can be applied to transistors with various structures.

[0081] When the pixel 11 is configured with multiple types of transistors using different semiconductor materials, the transistors may be provided in different layers for each type of transistor. For example, when the pixel 11 is configured with Si transistors and OS transistors, a layer including the Si transistors and a layer including the OS transistors may be provided in an overlapping manner. This configuration reduces the area occupied by the pixel 11.

[0082] Among the transistors constituting the pixel 11, the transistor M1 and the transistors M3 to M6 function as switches. Therefore, the display device 10 can be shown as in Figure 2. The transistor M1 and the transistors M3 to M6 can be replaced with elements that can implement the function of switches.

[0083] All or some of the transistors constituting the pixel 11 may be transistors having a back gate. Providing a back gate in a transistor makes it difficult for an electric field generated outside the transistor to act on a channel formation region, thereby stabilizing the operation of the display device and improving the reliability of the display device. Furthermore, applying the same potential to the back gate of a transistor as to its gate can reduce the on-resistance of the transistor. Furthermore, independently controlling the potential of the back gate of a transistor, separately from the potential of its gate, can change the threshold voltage of the transistor.

[0084] 3 shows an example of a circuit configuration of a display device 10 in which not only the transistor M2 but also the transistor M1 and the transistors M3 to M6 are configured as transistors having back gates. In FIG. 3, the gate and the back gate are electrically connected in each of the transistors M1 and the transistors M3 to M6. However, it is not necessary to provide a back gate in all of the transistors constituting the display device.

[0085] Alternatively, the gate and the back gate may not be electrically connected, and an arbitrary potential may be supplied to the back gate. Note that the potential supplied to the back gate is not limited to a fixed potential. The potential supplied to the back gate of each transistor included in the display device may be different or the same for each transistor.

[0086] The transistors constituting the pixel 11 may be single-gate transistors having one gate between the source and drain, or may be double-gate transistors. Fig. 4A shows an example of a circuit symbol for a double-gate transistor 180A.

[0087] The transistor 180A has a configuration in which a transistor Tr1 and a transistor Tr2 are connected in series. In the transistor 180A shown in FIG. 4A , one of the source or the drain of the transistor Tr1 is electrically connected to a terminal S. The other of the source or the drain of the transistor Tr1 is electrically connected to one of the source or the drain of the transistor Tr2. The other of the source or the drain of the transistor Tr2 is electrically connected to a terminal D. In the transistor 180A shown in FIG. 4A , the gates of the transistor Tr1 and the transistor Tr2 are electrically connected and also electrically connected to a terminal G.

[0088] 4A has a function of switching the conductive state between the terminal S and the terminal D and the non-conductive state by changing the potential of the terminal G. Therefore, the transistor 180A, which is a double-gate transistor, includes a transistor Tr1 and a transistor Tr2 and functions as a single transistor. That is, in FIG. 4A , one of the source and the drain of the transistor 180A is electrically connected to the terminal S, the other of the source and the drain is electrically connected to the terminal D, and the gate is electrically connected to the terminal G.

[0089] The transistor constituting the pixel 11 may be a triple-gate transistor. Fig. 4B shows an example of a circuit symbol for a triple-gate transistor 180B.

[0090] The transistor 180B has a configuration in which a transistor Tr1, a transistor Tr2, and a transistor Tr3 are connected in series. In the transistor 180B shown in FIG. 4B , one of the source or the drain of the transistor Tr1 is electrically connected to the terminal S. The other of the source or the drain of the transistor Tr1 is electrically connected to one of the source or the drain of the transistor Tr2. The other of the source or the drain of the transistor Tr2 is electrically connected to one of the source or the drain of the transistor Tr3. The other of the source or the drain of the transistor Tr3 is electrically connected to the terminal D. In the transistor 180B shown in FIG. 4B , the gates of the transistor Tr1, the transistor Tr2, and the transistor Tr3 are electrically connected and also electrically connected to the terminal G.

[0091] 4B has a function of switching the conductive state between the terminal S and the terminal D and the non-conductive state by changing the potential of the terminal G. Therefore, the transistor 180B, which is a triple-gate transistor, includes the transistors Tr1, Tr2, and Tr3 and functions as a single transistor. That is, in FIG. 4B, one of the source and the drain of the transistor 180B is electrically connected to the terminal S, the other of the source and the drain is electrically connected to the terminal D, and the gate is electrically connected to the terminal G.

[0092] The transistors constituting the pixel 11 may also be configured such that four or more transistors are connected in series. The transistor 180C shown in Fig. 4C has a configuration in which six transistors (transistors Tr1 to Tr6) are connected in series. In the transistor 180C shown in Fig. 4C, the gates of the six transistors are electrically connected to each other and are also electrically connected to the terminal G.

[0093] 4C has a function of switching the conduction state between the terminal S and the terminal D and the non-conduction state by changing the potential of the terminal G. Thus, the transistor 180C includes transistors Tr1 to Tr6 and functions as a single transistor. That is, in FIG. 4C , one of the source and the drain of the transistor 180C is electrically connected to the terminal S, the other of the source and the drain is electrically connected to the terminal D, and the gate is electrically connected to the terminal G.

[0094] A transistor having multiple gates electrically connected to each other, such as transistor 180A, transistor 180B, and transistor 180C, may be referred to as a "multi-gate transistor" or a "multi-gate transistor."

[0095] For example, when a transistor is operated in a saturation region, the channel length of the transistor may be increased to improve electrical characteristics in the saturation region. A multi-gate transistor may be used to realize a transistor with a long channel length.

[0096] <Example 1 of Correction Operation of Display Device> FIG. 5 is a flowchart illustrating an example of a correction method for the display device 10. FIG. 5 shows steps S01 to S05. First, step S01 is started. In step S01, the threshold voltage of the drive transistor (transistor M2) is corrected. After step S01 is completed, step S02 is started. In step S02, the current-voltage characteristics of the light-emitting element 61 are acquired. After step S02 is completed, step S03 is started. In step S03, the image data is corrected. After step S03 is completed, step S04 is started. In step S04, display data (corrected image data) is written. After step S04 is completed, step S05 is started. In step S05, the light-emitting element 61 is caused to emit light.

[0097] The specific operations of the display device 10 in steps S01 to S05 will be described below with reference to the drawings. Fig. 6 is a timing chart for explaining an example of the operation of the display device 10. Figs. 7 to 13 are circuit diagrams for explaining an example of the operation of the display device 10.

[0098] The wiring DL is supplied with display data Vdata generated by the image processing circuit 13 or a potential V0. The wiring ML is supplied with a potential V0 or potentials Ve1 to Ve4. The wiring 51 is supplied with a potential Va, the wiring 52 is supplied with a potential Vc, and the wiring 53 is supplied with a potential V1. The wirings GLa, GLb, and GLc are each supplied with either a potential H or a potential L. The potential H is preferably higher than the potential L. Note that in this specification and elsewhere, a "potential H" refers to a potential that is input to the gate of an n-channel transistor to turn the transistor on. A "potential L" refers to a potential that is input to the gate of an n-channel transistor to turn the transistor off.

[0099] The potential Va is an anode potential, and the potential Vc is a cathode potential. The potential V1 is preferably higher than the potential V0. The potential V1 may be a potential that, when applied to the back gate of the transistor M2, can shift the threshold voltage of the transistor M2 negatively until the transistor M2 is normally on. The potential V0 may be a potential that, when applied to the gate of the transistor M2, can turn the transistor M2 off. For example, the potential V0 can be 0 V or a potential L. The potential H is preferably higher than the potential V1.

[0100] The light emission intensity of the light emitting element 61 included in the pixel 11 is controlled by the magnitude of the current Ie (see FIG. 13 ) flowing through the light emitting element 61. The pixel 11 has a function of controlling the magnitude of the current Ie in accordance with the display data Vdata supplied from the image processing circuit 13 via the wiring DL.

[0101] In this embodiment and the like, the potential difference (voltage) between the gate and source of a transistor may be referred to as the "gate voltage." That is, "gate voltage of a transistor" = "potential of the gate of the transistor" - "potential of the source of the transistor." In addition, in this embodiment and the like, the potential difference (voltage) between the back gate and source of a transistor may be referred to as the "back gate voltage." That is, "back gate voltage of a transistor" = "potential of the back gate of the transistor" - "potential of the source of the transistor."

[0102] In the drawings, a symbol indicating a potential, such as "H", "L", "V0", or "V1" (also referred to as a "potential symbol"), may be written adjacent to, for example, a terminal or a wiring. To facilitate understanding of a potential change in, for example, a terminal or a wiring, a potential symbol attached to, for example, a terminal or a wiring that has experienced a potential change may be enclosed in letters. An "x" symbol may be added to a transistor in an off state.

[0103] Note that in this specification and elsewhere, a series of operations that change the conductive or non-conductive state of a transistor, supply charge to a node electrically connected to the transistor, and change the potential of the node may be referred to as "processing."

[0104] [Correction of Threshold Voltage of Driving Transistor] First, in step S01, a voltage for correcting the threshold voltage of the transistor M2 is obtained, and processing is performed to hold this voltage in the capacitor C2.

[0105] The current Ie flowing through the light-emitting element 61 is determined mainly by the display data Vdata and the threshold voltage of the transistor M2. Therefore, even if the same display data Vdata is supplied to multiple pixels, if the threshold voltage of the transistor M2 provided in each pixel is different, a different current Ie will flow for each pixel. Therefore, variations in the threshold voltage of the transistor M2 are one factor that cause a deterioration in the display quality of the display device.

[0106] Therefore, by correcting the threshold voltage of the transistor M2 for each pixel so that it has the same value, it is possible to reduce the variation in the current Ie. Note that in this embodiment, as an example, a method of correcting the threshold voltage of the transistor M2 so that it becomes 0 V by changing the potential applied to the back gate of the transistor M2 will be described.

[0107] First, in a period T11, a reset operation is performed. Specifically, a potential H is supplied to the wirings GLb and GLc, and a potential L is supplied to the wiring GLa (see FIG. 7).

[0108] Therefore, the transistors M3, M4, and M5 are turned on, and the transistors M1 and M6 are turned off.

[0109] Also, assume that the potential of node ND1 becomes potential Ve0. Furthermore, the potential of node ND3 also becomes potential Ve0 via transistor M3. Potential Ve0 is higher than potential Vc by the amount of voltage drop in light-emitting element 61. Furthermore, potential V1 is supplied to node ND2 via transistor M4. Assume that potential V1-potential Ve0 is applied as the back gate voltage of transistor M2, causing transistor M2 to enter a normally-on state.

[0110] Next, in a period T12, the potential L is supplied to the wiring GLc (see FIG. 8), which turns off the transistor M5.

[0111] Immediately after transistor M5 turns off, the back-gate voltage of transistor M2 is at potential V1-potential Ve0, so that transistor M2 is in a normally-on state. Therefore, charge is supplied to node ND1 from wiring 51 via transistor M2, and the potential of node ND1 rises over time. Furthermore, because transistor M3 is on, the potential of node ND3 also rises. Here, as the potential of node ND1 gradually rises, the back-gate voltage of transistor M2 gradually decreases. That is, the threshold voltage of transistor M2 gradually shifts in a positive direction. Finally, when the threshold voltage of transistor M2 approaches 0 V, transistor M2 turns off, and the rise in the potential of node ND1 stops. At this time, the back-gate voltage at which the threshold voltage of transistor M2 becomes 0 V is defined as Vb. That is, when the rise in the potential of node ND1 stops, the potential of node ND1 becomes potential V1-Vb.

[0112] Next, in a period T13, a potential L is supplied to the wiring GLb (see FIG. 9). As a result, the transistors M3 and M4 are turned off. Therefore, the nodes ND2 and ND3 are brought into a floating state, and the charges of the respective nodes are retained. In other words, the state in which Vb obtained in the period T12 is applied as the back-gate voltage of the transistor M2 is maintained.

[0113] By performing the processes in the periods T11 to T13, the threshold voltage of the transistor M2 is corrected to 0 V, and the corrected state can be maintained. Note that in the present embodiment and the like, such a correction method for a display device may be referred to as "internal correction."

[0114] [Obtaining Current-Voltage Characteristics of Light-Emitting Element] Next, in step S02, the monitor circuit 12 measures the current flowing through the light-emitting element 61, and a process for obtaining the current-voltage characteristics of the light-emitting element 61 is performed.

[0115] The light emission intensity of the light emitting element 61 is determined by the current Ie flowing through the light emitting element 61. The current Ie flowing through the light emitting element 61 is determined by the potential difference (voltage) between the anode terminal and the cathode terminal of the light emitting element 61. Furthermore, the characteristics of the light emitting element 61 for each pixel may vary or deteriorate over time, for example. Therefore, even if the threshold voltage of the drive transistor is corrected as described above, the final light emission intensity of the light emitting element 61 may vary, which may result in a decrease in the display quality of the display device, such as display unevenness.

[0116] Therefore, by acquiring the current-voltage characteristics of the light-emitting element 61 and correcting the image data using the acquired current-voltage characteristics, it is possible to reduce the degradation of the display quality of the display device due to, for example, characteristic variations or characteristic degradation of the light-emitting element 61.

[0117] An example of a process for acquiring the current-voltage characteristics of the light-emitting element 61 will be described. First, in a period T21, a potential H is supplied to the wiring GLa and the wiring GLc, and a potential L is supplied to the wiring GLb (see FIG. 10). As a result, the transistors M1, M5, and M6 are turned on, and the transistors M3 and M4 are turned off. Furthermore, a potential V0 is supplied to the wiring DL, so that the transistor M2 is turned off.

[0118] A potential Ve1 is supplied from the monitor circuit 12 to the wiring ML. Note that the potential Ve1 is preferably higher than the potential V0. As a result, the potential Ve1 is supplied to the anode terminal of the light-emitting element 61 via the transistors M6 and M5. Then, a voltage of potential Ve1-potential Vc is applied across both ends of the light-emitting element 61 (between the anode terminal and the cathode terminal), and a current Ie1 corresponding to the applied voltage flows through the light-emitting element 61. The current Ie1 flows from the monitor circuit 12 to the light-emitting element 61 via the wiring ML, transistor M6, node ND1, and transistor M5. Therefore, the current Ie1 can be measured by the monitor circuit 12. In other words, the current Ie1 that flows when a voltage of potential Ve1-potential Vc is applied across the light-emitting element 61 can be obtained.

[0119] Next, in period T22, a potential Ve2 is supplied from the monitor circuit 12 to the wiring ML while the potentials of the wiring GLa, the wiring GLb, the wiring GLc, and the wiring DL are maintained. Then, as in period T21, the current Ie2 that flows when a voltage of potential Ve2 minus potential Vc is applied to both ends of the light-emitting element 61 can be obtained. Similarly, in period T23, a potential Ve3 is supplied to the wiring ML, so that the current Ie3 that flows when a voltage of potential Ve3 minus potential Vc is applied to both ends of the light-emitting element 61 can be obtained. Similarly, in period T24, a potential Ve4 is supplied to the wiring ML, so that the current Ie4 that flows when a voltage of potential Ve4 minus potential Vc is applied to both ends of the light-emitting element 61 can be obtained. Note that after the end of period T24, a potential L is supplied to the wiring GLa and the wiring GLc, so that the transistors M1, M5, and M6 are turned off.

[0120] By performing the processes in the periods T21 to T24, it is possible to measure the currents Ie1 to Ie4 flowing through the light-emitting element 61 when the potentials Ve1 to Ve4 are supplied to the anode terminal of the light-emitting element 61. In other words, it is possible to obtain the current-voltage characteristics of the light-emitting element 61.

[0121] Here, an example has been shown in which four pieces of characteristic data are acquired when one piece of characteristic data is a pair of a voltage value applied across the light-emitting element 61 and a corresponding current value flowing through the light-emitting element 61, but this is not limiting. The number of pieces of characteristic data to be acquired may be two, three, or five or more. By acquiring a larger number of pieces of characteristic data, it is possible to acquire more accurate current-voltage characteristics of the light-emitting element 61.

[0122] [Image Data Correction] Next, in step S03, the image data is corrected using the current-voltage characteristics of the light-emitting elements 61 acquired in step S02, and display data Vdata is generated.

[0123] For example, the current-voltage characteristics of the light-emitting element 61 may be obtained for each pixel, and the image data may be corrected to cancel out the variations. For example, the correction amount ΔVthO of the image data may be obtained for each pixel, and the image data may be corrected using the formula: display data Vdata=image data+ΔVthO, thereby generating the display data Vdata.

[0124] By performing the processes of steps S02 and S03, it is possible to correct image data using the current-voltage characteristics of the light-emitting element 61. Note that in the present embodiment and the like, such a correction method for a display device may be referred to as "external correction."

[0125] In addition, in the present embodiment, an example of external correction in which the current-voltage characteristics of the light-emitting element 61 are acquired and the image data is corrected has been shown, but the present invention is not limited to this. For example, the image data may be corrected by acquiring the characteristics of the drive transistor, or the image data may be corrected by acquiring the characteristics of both the light-emitting element 61 and the drive transistor.

[0126] [Writing Display Data] Next, in step S04, processing for writing the display data Vdata to the pixels 11 is performed.

[0127] In the period T31, a potential H is supplied to the wiring GLa, and a potential L is supplied to the wirings GLb and GLc (see FIG. 11). Then, the transistor M1 is turned on, and the display data Vdata is supplied to the node ND3. The transistor M6 is turned on, and the potential V0 is supplied to the node ND1. That is, the display data Vdata -potential V0 is applied to the gate voltage of the transistor M2.

[0128] Because the nodes ND1 and ND2 are capacitively coupled via the capacitor C2, when the potential of the node ND1 changes to the potential V0, the potential of the node ND2 also changes to the potential V0+Vb. That is, Vb is applied to the back gate voltage of the transistor M2, and the display data Vdata can be written while maintaining the state in which the threshold voltage of the transistor M2 is corrected to 0 V.

[0129] Next, in a period T32, a potential L is supplied to the wiring GLa (see FIG. 12). Then, the transistor M1 is turned off, and the node ND3 is brought into a floating state. In addition, the transistor M6 is turned off, and charge is supplied to the node ND1 from the wiring 51 through the transistor M2, so that the potential of the node ND1 gradually increases.

[0130] Here, node ND3 is floating, and nodes ND1 and ND3 are capacitively coupled via capacitor C1. Therefore, the potential of node ND3 also rises following the rise in the potential of node ND1. That is, the gate voltage of transistor M2 is maintained at display data Vdata - potential V0. Similarly, node ND2 is floating, and nodes ND1 and ND2 are capacitively coupled via capacitor C2. Therefore, the potential of node ND2 also rises following the rise in the potential of node ND1. That is, the back gate voltage of transistor M2 is maintained at Vb.

[0131] [Light Emission of Light-Emitting Element] Next, in period T33, a potential H is supplied to the wiring GLc (see FIG. 13). This turns on the transistor M5, causing a current to flow from the wiring 51 to the wiring 52. That is, a current Ie flows through the light-emitting element 61, and the light-emitting element 61 emits light with an intensity corresponding to the current Ie.

[0132] The current flowing from the wiring 51 to the wiring 52 changes the potential of the node ND1. As in the period T32 described above, the nodes ND2 and ND3 are floating. Therefore, the gate voltage of the transistor M2 is maintained at the display data Vdata-potential V0, and the back gate voltage of the transistor M2 is maintained at Vb.

[0133] Here, the current Ie is determined by the gate voltage and back gate voltage of transistor M2. That is, the current Ie is proportional to the square of ("gate voltage of transistor M2" - "threshold voltage of transistor M2"). A state in which the display data Vdata - potential V0 is applied as the gate voltage of transistor M2 is maintained. Also, a state in which Vb is applied as the back gate voltage of transistor M2 is maintained. In other words, a state in which the threshold voltage of transistor M2 is corrected to 0 V is maintained. That is, the current Ie is proportional to the square of (display data Vdata - potential V0), and a state in which a current amount that does not depend on the threshold voltage of transistor M2 flows is maintained.

[0134] In the display device 10 according to one embodiment of the present invention, the threshold voltage of the transistor M2 is corrected by internal correction, and the current-voltage characteristics of the light-emitting element 61 are corrected by external correction, thereby improving the display quality of the display device 10.

[0135] <Example 2 of Correction Operation of Display Device> Note that the correction method of the display device of one embodiment of the present invention is not limited to the above description. In the correction method of the display device of one embodiment of the present invention, it is sufficient that both the correction of the threshold voltage of the driving transistor in step S01 and the correction of the image data in step S03 are completed before starting writing of the display data in step S04.

[0136] 14 is a flowchart illustrating another example of a method for correcting the display device 10. The method for correcting the display device illustrated in FIG. 14 differs from the method for correcting the display device illustrated in FIG. 5 in the order in which steps S01 to S05 are performed. First, step S02 is started. After step S02 is completed, steps S01 and S03 are started. After step S01 and step S03 are completed, step S04 is started. After step S04 is completed, step S05 is started. Note that the operation of the display device 10 in each of steps S01 to S05 can be understood from the above description.

[0137] Note that step S01 is processing in the pixel 11, and step S03 is processing in the image processing circuit 13. Therefore, step S01 and step S03 can be performed simultaneously. That is, step S01 and step S03 may be started simultaneously after step S02 is completed. By performing step S01 and step S03 simultaneously, the time required for correction of the display device 10 can be shortened. That is, the operating speed of the display device 10 can be increased.

[0138] <Specific Configuration Example of Display Device> Next, a more detailed configuration example of the display device 10 shown in Fig. 1 will be described. Fig. 15 shows an example of the configuration of the display device 10 according to one embodiment of the present invention in a block diagram. Note that in the block diagram, components are classified by function and shown as independent blocks, but in reality, it is difficult to completely separate the components by function, and one component may be involved in multiple functions.

[0139] 15 includes a panel 25 having a plurality of pixels 11 in a pixel section 24, a controller 26, a CPU 27, an image processing circuit 13, an image memory 28, a memory 29, and a monitor circuit 12. The display device 10 shown in FIG. 15 also includes a drive circuit 30 and a drive circuit 31 in the panel 25.

[0140] The CPU 27 has the function of comprehensively controlling the operation of various circuits in the display device 10, decoding commands input from the outside or commands stored in memory provided within the CPU 27, and executing those commands.

[0141] The monitor circuit 12 has a function of supplying an arbitrary potential to the pixel 11 and measuring the current flowing through the pixel 11 at that time. It also has a function of generating arbitrary data (e.g., current-voltage characteristics of the light-emitting element 61) based on the measured current. The memory 29 has a function of storing information contained in the signal. The memory 29 may be a volatile memory such as a DRAM or an SRAM, or a nonvolatile memory such as a flash memory, an MRAM, a magnetic memory, a magnetic disk, or a magneto-optical disk. For example, by using a nonvolatile memory as the memory 29, information about each pixel can be stored even after the power supply is stopped. This eliminates the need to constantly measure the current flowing through the pixel 11. For example, the current flowing through the pixel 11 can be measured only before shipping the product, immediately before the power supply is stopped, or immediately after the power supply is started, and the measured information can be stored in the memory 29.

[0142] The image memory 28 has a function of storing image data 32 input to the display device 10. Although Fig. 15 illustrates an example in which only one image memory 28 is provided in the display device 10, a plurality of image memories 28 may be provided in the display device 10. For example, when a full-color image is displayed in the pixel unit 24 using three pieces of image data 32 each corresponding to a hue such as red, blue, or green, three image memories 28 corresponding to the three pieces of image data 32 may be provided.

[0143] The image memory 28 may be implemented using a storage circuit such as a dynamic random access memory (DRAM) or a static random access memory (SRAM). Alternatively, the image memory 28 may be implemented using a video random access memory (VRAM).

[0144] The image processing circuit 13 has a function of writing image data 32 to an image memory 28 and reading image data 32 from the image memory 28 in accordance with instructions from the CPU 27, and generating display data Vdata from the image data 32. The image processing circuit 13 also has a function of reading information stored in a memory 29 in accordance with instructions from the CPU 27, and correcting the image data using the information. The memory 29 stores arbitrary data (e.g., current-voltage characteristics of the light-emitting elements 61) generated in the monitor circuit 12. That is, for example, the image data 32 can be corrected using the current-voltage characteristics of the light-emitting elements 61.

[0145] When display data Vdata having image information is input, the controller 26 performs signal processing on the display data Vdata in accordance with the specifications of the panel 25 and then supplies the processed data to the panel 25 .

[0146] The drive circuit 31 has a function of selecting, for each row, the plurality of pixels 11 included in the pixel unit 24. The drive circuit 30 also has a function of supplying display data Vdata provided from the controller 26 to the pixels 11 in the row selected by the drive circuit 31.

[0147] The controller 26 has a function of supplying various drive signals used to drive the drive circuit 30, the drive circuit 31, etc. to the panel 25. The drive signals include, for example, a start pulse signal SSP, a clock signal SCK, and a latch signal LP that control the operation of the drive circuit 30, a start pulse signal GSP that controls the operation of the drive circuit 31, and a clock signal GCK.

[0148] The display device 10 may also have an input device that has a function of providing, for example, information or commands to the CPU 27 of the display device 10. For example, a keyboard, a pointing device, a touch panel, or a sensor can be used as the input device.

[0149] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0150] In this embodiment, a configuration example of a display device to which the correction method for a display device according to one embodiment of the present invention can be applied will be described. The display device exemplified below can be applied to, for example, the pixel 11 in Embodiment 1.

[0151] One embodiment of the present invention is a display device having a light-emitting element (also referred to as a light-emitting device). The display device has two or more light-emitting elements that emit light of different colors. Each light-emitting element has a pair of electrodes and an EL layer therebetween. The light-emitting element is preferably an organic EL element (organic electroluminescent element). The two or more light-emitting elements that emit light of different colors each have an EL layer containing a different light-emitting material. For example, a full-color display device can be realized by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light.

[0152] When fabricating a display device having multiple light-emitting elements each emitting different colors, it is necessary to form at least layers (light-emitting layers) containing light-emitting materials emitting different colors in an island shape. When partially or entirely fabricating an EL layer, a method of forming island-shaped organic films by vapor deposition using a shadow mask such as a metal mask is known. However, with this method, deviations in the shape and position of the island-shaped organic films from the design occur due to various factors, such as the accuracy of the metal mask, misalignment between the metal mask and the substrate, deflection of the metal mask, and the spread of the contours of the deposited film due to, for example, vapor scattering, making it difficult to achieve high definition and a high aperture ratio. Furthermore, during vapor deposition, the contours of the layer may become blurred, resulting in a thin edge. In other words, the thickness of the island-shaped light-emitting layer may vary depending on the location. Furthermore, when fabricating large, high-resolution, or high-definition display devices, there is a concern that the manufacturing yield may be low due to, for example, low dimensional accuracy of the metal mask and deformation due to heat. Therefore, measures have been taken to artificially increase the resolution (also called pixel density) by adopting special pixel arrangement methods such as a pentile arrangement.

[0153] In this specification, the term "island-like" refers to a state in which two or more layers formed using the same material in the same process are physically separated. For example, an island-like light-emitting layer refers to a state in which the light-emitting layer is physically separated from an adjacent light-emitting layer.

[0154] In one embodiment of the present invention, an EL layer is processed into a fine pattern by photolithography without using a shadow mask such as a fine metal mask (FMM). This makes it possible to realize a display device with high definition and a large aperture ratio, which have been difficult to achieve until now. Furthermore, because the EL layer can be individually fabricated, a display device with extremely vivid images, high contrast, and high display quality can be realized. For example, the EL layer may be processed into a fine pattern by using both a metal mask and photolithography.

[0155] Furthermore, the EL layer can be partially or entirely separated physically. This can suppress leakage current between adjacent light-emitting elements through a layer shared between the light-emitting elements (also referred to as a common layer). This can prevent crosstalk caused by unintended light emission, thereby realizing a display device with extremely high contrast. In particular, a display device with high current efficiency at low luminance can be realized.

[0156] One embodiment of the present invention can also be a display device that combines a white-emitting light-emitting element and a color filter. In this case, light-emitting elements provided in pixels (subpixels) that emit light of different colors can have the same configuration, and all layers can be common layers. Furthermore, part or all of each EL layer is separated by photolithography. This suppresses leakage current through the common layer, thereby realizing a display device with high contrast. In particular, in an element having a tandem structure in which multiple light-emitting layers are stacked via a highly conductive intermediate layer, leakage current through the intermediate layer can be effectively prevented, thereby realizing a display device that combines high brightness, high definition, and high contrast.

[0157] Furthermore, it is preferable to provide an insulating layer that covers at least the side surfaces of the island-shaped light-emitting layers. The insulating layer may be configured to cover a portion of the top surface of the island-shaped EL layer. The insulating layer is preferably made of a material that has barrier properties against water and oxygen. For example, an inorganic insulating film that is difficult for water or oxygen to diffuse can be used. This suppresses deterioration of the EL layer and realizes a highly reliable display device.

[0158] Furthermore, there is a region (recess) between two adjacent light-emitting elements where the EL layer of either light-emitting element is not provided. When a common electrode, or a common electrode and a common layer, is formed to cover the recess, a phenomenon in which the common electrode is separated by a step at the edge of the EL layer (also called a step discontinuity) may occur, resulting in insulation of the common electrode on the EL layer. Therefore, it is preferable to use a configuration in which the local step located between two adjacent light-emitting elements is filled with a resin layer functioning as a planarization film (also called LFP: Local Filling Planarization). The resin layer functions as a planarization film. This suppresses step discontinuity of the common layer or common electrode, thereby achieving a highly reliable display device.

[0159] A more specific example of the structure of the display device of one embodiment of the present invention will be described below with reference to the drawings.

[0160] 16A is a schematic top view of a display device 100 of one embodiment of the present invention. The display device 100 includes a plurality of light-emitting elements 110R that exhibit red light, a plurality of light-emitting elements 110G that exhibit green light, and a plurality of light-emitting elements 110B that exhibit blue light over a substrate 101. In FIG. 16A , the light-emitting regions of the light-emitting elements are labeled with R, G, or B to easily distinguish the light-emitting elements from one another.

[0161] The light-emitting elements 110R, 110G, and 110B are arranged in a matrix. Fig. 16A shows a so-called stripe arrangement in which light-emitting elements emitting light of the same color are arranged in one direction. Note that the arrangement method of the light-emitting elements is not limited to this, and arrangement methods such as an S-stripe arrangement, a delta arrangement, a Bayer arrangement, or a zigzag arrangement may also be applied, or for example, a pentile arrangement or a diamond arrangement may also be used.

[0162] As the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B, for example, an OLED (organic light-emitting diode) or a QLED (quantum-dot light-emitting diode) is preferably used. Examples of the light-emitting material contained in the EL element include a fluorescent material, a phosphorescent material, an inorganic compound (e.g., a quantum dot material), and a material that exhibits thermally activated delayed fluorescence (TADF material).

[0163] 16A also shows a connection electrode 111C that is electrically connected to the common electrode 113. The connection electrode 111C is given a potential (e.g., an anode potential or a cathode potential) to be supplied to the common electrode 113. The connection electrode 111C is provided outside the display area where, for example, the light-emitting elements 110R and the like are arranged.

[0164] The connection electrode 111C can be provided along the periphery of the display area. For example, it may be provided along one side of the periphery of the display area, or it may be provided over two or more sides of the periphery of the display area. That is, when the top surface shape of the display area is rectangular, the top surface shape of the connection electrode 111C can be, for example, a strip shape (rectangle), an L-shape, a U-shape (square bracket shape), or a square shape.

[0165] 16B and 16C are schematic cross-sectional views corresponding to dashed dotted lines A1-A2 and A3-A4 in Fig. 16A, respectively. Fig. 16B shows a schematic cross-sectional view of light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B, and Fig. 16C shows a schematic cross-sectional view of connection portion 140 where connection electrode 111C and common electrode 113 are connected.

[0166] The light-emitting element 110R has a pixel electrode 111R, an organic layer 112R, a common layer 114, and a common electrode 113. The light-emitting element 110G has a pixel electrode 111G, an organic layer 112G, a common layer 114, and a common electrode 113. The light-emitting element 110B has a pixel electrode 111B, an organic layer 112B, a common layer 114, and a common electrode 113. The common layer 114 and the common electrode 113 are provided in common to the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B.

[0167] The organic layer 112R of the light-emitting element 110R contains a light-emitting organic compound that emits light having an intensity in at least the red wavelength range. The organic layer 112G of the light-emitting element 110G contains a light-emitting organic compound that emits light having an intensity in at least the green wavelength range. The organic layer 112B of the light-emitting element 110B contains a light-emitting organic compound that emits light having an intensity in at least the blue wavelength range. The organic layer 112R, the organic layer 112G, and the organic layer 112B can also be referred to as an EL layer, and each contains at least a layer (light-emitting layer) containing a light-emitting organic compound.

[0168] Hereinafter, when describing matters common to light emitting element 110R, light emitting element 110G, and light emitting element 110B, they may be referred to as light emitting element 110. Similarly, when describing matters common to components distinguished by alphabets, such as organic layer 112R, organic layer 112G, and organic layer 112B, they may be described using symbols without the alphabets.

[0169] The organic layer 112 and the common layer 114 may each independently include one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. For example, the organic layer 112 may have a stacked structure of a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer in this order from the pixel electrode 111 side, and the common layer 114 may have an electron injection layer.

[0170] The pixel electrode 111R, the pixel electrode 111G, and the pixel electrode 111B are each provided for each light-emitting element. The common layer 114 and the common electrode 113 are provided as a continuous layer common to each light-emitting element. A conductive film that is translucent to visible light is used for either the pixel electrode or the common electrode 113, and a conductive film that is reflective is used for the other. By making each pixel electrode translucent and the common electrode 113 reflective, a bottom-emission display device can be obtained. Conversely, by making each pixel electrode reflective and the common electrode 113 translucent, a top-emission display device can be obtained. Note that by making both the pixel electrodes and the common electrode 113 translucent, a dual-emission display device can also be obtained.

[0171] A protective layer 121 is provided on the common electrode 113 to cover the light emitting elements 110R, 110G, and 110B. The protective layer 121 has a function of preventing impurities such as water from diffusing from above to each light emitting element.

[0172] The edge of the pixel electrode 111 preferably has a tapered shape. When the edge of the pixel electrode has a tapered shape, the organic layer 112 provided along the side surface of the pixel electrode also has a tapered shape. By tapering the side surface of the pixel electrode, the coverage of the EL layer provided along the side surface of the pixel electrode can be improved. Furthermore, by tapering the side surface of the pixel electrode, foreign matter (for example, dust or particles) during the manufacturing process can be easily removed by a process such as cleaning, which is preferable.

[0173] In this specification and the like, the term "tapered shape" refers to a shape in which at least a part of a side surface of a structure is inclined with respect to a substrate surface. For example, it is preferable that the structure has a region in which the angle between the inclined side surface and the substrate surface (also referred to as the taper angle) is less than 90°.

[0174] The organic layer 112 is processed into an island shape by photolithography. As a result, the angle between the top surface and the side surface of the organic layer 112 at its edge is close to 90 degrees. On the other hand, an organic film formed using, for example, a fine metal mask (FMM) tends to become gradually thinner toward the edge, and the top surface is formed in a sloped shape over a range of, for example, 1 μm to 10 μm, making it difficult to distinguish between the top surface and the side surface.

[0175] Between two adjacent light emitting elements, an insulating layer 125, a resin layer 126, and a layer 128 are provided.

[0176] Between two adjacent light-emitting elements, the side surfaces of the organic layers 112 face each other with the resin layer 126 interposed therebetween. The resin layer 126 is located between the two adjacent light-emitting elements and is provided so as to fill the ends of each organic layer 112 and the region between the two organic layers 112. The resin layer 126 has a smooth, convex upper surface, and a common layer 114 and a common electrode 113 are provided covering the upper surface of the resin layer 126.

[0177] The resin layer 126 functions as a planarization film that fills in a step located between two adjacent light-emitting elements. By providing the resin layer 126, it is possible to prevent a phenomenon (also called step disconnection) in which the common electrode 113 is divided by a step at the end of the organic layer 112, and the common electrode on the organic layer 112 is isolated. The resin layer 126 can also be called LFP (Local Filling Planarization).

[0178] An insulating layer containing an organic material can be suitably used as the resin layer 126. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, or precursors of these resins can be used as the resin layer 126. 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 resin layer 126.

[0179] Furthermore, a photosensitive resin can be used as the resin layer 126. A photoresist can be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0180] The resin layer 126 may contain a material that absorbs visible light. For example, the resin layer 126 itself may be made of a material that absorbs visible light, or the resin layer 126 may contain a pigment that absorbs visible light. For example, the resin layer 126 may be a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and functions as a black matrix.

[0181] The insulating layer 125 is provided in contact with the side surface of the organic layer 112. The insulating layer 125 is also provided to cover the upper end portion of the organic layer 112. A portion of the insulating layer 125 is provided in contact with the upper surface of the substrate 101.

[0182] The insulating layer 125 is located between the resin layer 126 and the organic layer 112, and functions as a protective film for preventing the resin layer 126 from contacting the organic layer 112. If the organic layer 112 and the resin layer 126 come into contact with each other, the organic layer 112 may be dissolved by an organic solvent or the like used when forming the resin layer 126. Therefore, as shown in this embodiment, by providing the insulating layer 125 between the organic layer 112 and the resin layer 126, it is possible to protect the side surfaces of the organic layer.

[0183] The insulating layer 125 can be an insulating layer containing an inorganic material. For example, an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film can be used for the insulating layer 125. The insulating layer 125 may have a single-layer structure or a stacked-layer structure. Examples of oxide insulating films include a silicon oxide film, an aluminum oxide film, a magnesium oxide film, an indium gallium zinc oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, or a tantalum oxide film. Examples of nitride insulating films include a silicon nitride film or an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film or an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film or an aluminum nitride oxide film. In particular, by applying a metal oxide film such as an aluminum oxide film or a hafnium oxide film, or an inorganic insulating film such as a silicon oxide film, formed by the ALD method, to the insulating layer 125, it is possible to form an insulating layer 125 with few pinholes and excellent function of protecting the EL layer.

[0184] In this specification and elsewhere, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0185] The insulating layer 125 can be formed by, for example, a sputtering method, a CVD method, a PLD method, an ALD method, or the like. The insulating layer 125 is preferably formed by an ALD method because it has good coverage.

[0186] Furthermore, a reflective film (e.g., a metal film containing one or more selected from silver, palladium, copper, titanium, aluminum, etc.) may be provided between the insulating layer 125 and the resin layer 126, so that the light emitted from the light-emitting layer is reflected by the reflective film, thereby improving the light extraction efficiency.

[0187] The layer 128 is a remaining portion of a protective layer (also referred to as a mask layer or a sacrificial layer) for protecting the organic layer 112 during etching of the organic layer 112. The layer 128 can be made of a material that can be used for the insulating layer 125. In particular, it is preferable to use the same material for the layer 128 and the insulating layer 125 because, for example, a common processing device or the like can be used for both layers.

[0188] In particular, metal oxide films such as aluminum oxide films or hafnium oxide films, or inorganic insulating films such as silicon oxide films formed by the ALD method have few pinholes and are therefore excellent in the function of protecting the EL layer, and can be suitably used for the insulating layer 125 and the layer 128.

[0189] A protective layer 121 is provided to cover the common electrode 113 .

[0190] The protective layer 121 may have, for example, a single-layer structure or a multilayer structure including at least an inorganic insulating film. Examples of the inorganic insulating film include oxide films or nitride films such as a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, an aluminum oxynitride film, or a hafnium oxide film. Alternatively, the protective layer 121 may be made of a semiconductor material or a conductive material such as indium gallium oxide, indium zinc oxide, indium tin oxide, or indium gallium zinc oxide.

[0191] The protective layer 121 may also be a laminated film of an inorganic insulating film and an organic insulating film. For example, a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films is preferable. Furthermore, it is preferable that the organic insulating film functions as a planarizing film. This allows the upper surface of the organic insulating film to be flat, thereby improving the coverage of the inorganic insulating film thereon and enhancing the barrier properties. Furthermore, since the upper surface of the protective layer 121 is flat, when a structure (e.g., a color filter, a touch sensor electrode, a lens array, etc.) is provided above the protective layer 121, the influence of uneven shapes caused by the structure below can be reduced, which is preferable.

[0192] 16C shows a connection portion 140 where the connection electrode 111C and the common electrode 113 are electrically connected. In the connection portion 140, an opening is provided in the insulating layer 125 and the resin layer 126 above the connection electrode 111C. The connection electrode 111C and the common electrode 113 are electrically connected in the opening.

[0193] 16C shows a connection portion 140 where the connection electrode 111C and the common electrode 113 are electrically connected, but the common electrode 113 may be provided on the connection electrode 111C via the common layer 114. In particular, for example, when a carrier injection layer is used for the common layer 114, the electrical resistivity of the material used for the common layer 114 is sufficiently low and the common layer 114 can be formed thin, so that there is often no problem even if the common layer 114 is located at the connection portion 140. This allows the common electrode 113 and the common layer 114 to be formed using the same masking mask, thereby reducing manufacturing costs.

[0194] The above is a description of an example of the configuration of the display device.

[0195] [Pixel Layout] The following mainly describes pixel layouts that are different from that shown in Fig. 16A. There are no particular limitations on the arrangement of light-emitting elements (sub-pixels), and various methods can be applied.

[0196] Examples of the top surface shape of the sub-pixel include a triangle, a quadrangle (including a rectangle or a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, a circle, etc. Here, the top surface shape of the sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting element.

[0197] An S-stripe arrangement is applied to the pixel 150 shown in Fig. 17A. The pixel 150 shown in Fig. 17A is composed of three sub-pixels: a light-emitting element 110a, a light-emitting element 110b, and a light-emitting element 110c. For example, the light-emitting element 110a may be a light-emitting element that emits blue light, the light-emitting element 110b may be a light-emitting element that emits red light, and the light-emitting element 110c may be a light-emitting element that emits green light.

[0198] The pixel 150 shown in FIG. 17B includes a light-emitting element 110a having a generally trapezoidal top surface shape with rounded corners, a light-emitting element 110b having a generally triangular top surface shape with rounded corners, and a light-emitting element 110c having a generally rectangular or hexagonal top surface shape with rounded corners. Furthermore, the light-emitting element 110a has a larger light-emitting area than the light-emitting element 110b. In this manner, the shape and size of each light-emitting element can be determined independently. For example, the more reliable the light-emitting element, the smaller the size can be. For example, the light-emitting element 110a may emit green light, the light-emitting element 110b may emit red light, and the light-emitting element 110c may emit blue light.

[0199] The pixel 124a and the pixel 124b shown in Fig. 17C are arranged in a Pentile arrangement. Fig. 17C shows an example in which the pixel 124a having the light-emitting element 110a and the light-emitting element 110b and the pixel 124b having the light-emitting element 110b and the light-emitting element 110c are arranged alternately. For example, the light-emitting element 110a may be an light-emitting element that emits red light, the light-emitting element 110b may be an light-emitting element that emits green light, and the light-emitting element 110c may be an light-emitting element that emits blue light.

[0200] 17D and 17E are arranged in a delta configuration. The pixel 124a has two light-emitting elements (light-emitting elements 110a and 110b) in the top row (first row) and one light-emitting element (light-emitting element 110c) in the bottom row (second row). The pixel 124b has one light-emitting element (light-emitting element 110c) in the top row (first row) and two light-emitting elements (light-emitting element 110a and light-emitting element 110b) in the bottom row (second row). For example, the light-emitting element 110a may be a light-emitting element that emits red light, the light-emitting element 110b may be a light-emitting element that emits green light, and the light-emitting element 110c may be a light-emitting element that emits blue light.

[0201] FIG. 17D shows an example in which each light-emitting element has a substantially rectangular top surface shape with rounded corners, and FIG. 17E shows an example in which each light-emitting element has a circular top surface shape.

[0202] 17F shows an example in which light-emitting elements emitting light of each color are arranged in a zigzag pattern. Specifically, when viewed from above, the positions of the upper edges of two light-emitting elements arranged in a column direction (e.g., light-emitting elements 110a and 110b, or light-emitting elements 110b and 110c) are offset. For example, light-emitting element 110a may be a light-emitting element that emits red light, light-emitting element 110b may be a light-emitting element that emits green light, and light-emitting element 110c may be a light-emitting element that emits blue light.

[0203] In photolithography, the finer the pattern to be processed, the more significant the effect of light diffraction becomes. This reduces the fidelity of the photomask pattern when it is transferred by exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, it is likely to have rounded corners. Therefore, the top surface shape of the light-emitting element may be, for example, a polygon with rounded corners, an ellipse, or a circle.

[0204] Furthermore, in a manufacturing method of a display panel according to one embodiment of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, the resist film may not be cured sufficiently depending on the heat resistance temperature of the material for the EL layer and the curing temperature of the resist material. A resist film that is not cured sufficiently may have a shape that is different from the desired shape during processing. As a result, the top surface shape of the EL layer may be, for example, a polygon with rounded corners, an ellipse, or a circle. For example, when a resist mask with a square top surface shape is formed, a resist mask with a circular top surface shape is formed, resulting in a circular top surface shape of the EL layer.

[0205] In order to form the top surface of the EL layer into a desired shape, a technique for correcting a mask pattern in advance (OPC (Optical Proximity Correction) technique) may be used so that the design pattern and the transfer pattern coincide with each other. Specifically, in the OPC technique, a correction pattern is added to, for example, the corners of figures on the mask pattern.

[0206] This concludes the description of the pixel layout.

[0207] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0208] Embodiment 3 In this embodiment, a structural example of a display device that can be used for a method for correcting a display device according to one embodiment of the present invention will be described.

[0209] The display device of this embodiment can be used in electronic devices with relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, or large game machines such as pachinko machines, as well as in the display section of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, smartphones, wristwatch-type terminals, tablet terminals, personal digital assistants, or sound playback devices.

[0210] [Display Device 400] FIG. 18 shows a perspective view of display device 400, and FIG. 19A shows a cross-sectional view of display device 400.

[0211] The display device 400 has a configuration in which a substrate 452 and a substrate 451 are bonded together. In Fig. 18, the substrate 452 is clearly indicated by a dashed line.

[0212] The display device 400 includes, for example, a display portion 462, a circuit 464, and wiring 465. Fig. 18 shows an example in which an IC 473 and an FPC 472 are mounted on the display device 400. Therefore, the configuration shown in Fig. 18 can also be considered as a display module including the display device 400, an IC (integrated circuit), and an FPC.

[0213] The circuit 464 can be, for example, a scanning line driver circuit.

[0214] The wiring 465 has a function of supplying signals and power to the display portion 462 and the circuit 464. The signals and power are input to the wiring 465 from the outside of the display device 400 via the FPC 472 or are input to the wiring 465 from the IC 473.

[0215] 18 shows an example in which an IC 473 is provided on a substrate 451 by, for example, a chip-on-glass (COG) method or a chip-on-film (COF) method. The IC 473 can be, for example, an IC having a scanning line driver circuit or a signal line driver circuit. The display device 400 or the display module may not include an IC. Alternatively, the IC may be mounted on an FPC by, for example, a COF method.

[0216] 19A shows an example of a cross section of a part of a region including an FPC 472, a part of a circuit 464, a part of a display portion 462, and a part of a region including a connection portion of the display device 400. In FIG. 19A, an example of a cross section of the display portion 462 is shown, in particular, when a region including a light-emitting element 430b that emits green light and a light-emitting element 430c that emits blue light is cut.

[0217] The display device 400 shown in FIG. 19A includes, for example, the transistor 202, the transistor 210, the light-emitting element 430b, and the light-emitting element 430c between a substrate 453 and a substrate 454.

[0218] The light-emitting element described as an example in Embodiment 1 can be applied to the light-emitting element 430b and the light-emitting element 430c.

[0219] Here, when a pixel of a display device has three types of subpixels having light-emitting elements that emit different colors, the three subpixels may be, for example, subpixels that emit light of three colors: red (R), green (G), and blue (B), or subpixels that emit light of three colors: yellow (Y), cyan (C), and magenta (M). When a pixel of a display device has four such subpixels, the four subpixels may be, for example, subpixels that emit light of four colors: R, G, B, and white (W), or subpixels that emit light of four colors: R, G, B, and Y.

[0220] The substrate 454 and the protective layer 416 are bonded to each other via an adhesive layer 442. The adhesive layer 442 is provided to overlap the light-emitting element 430b and the light-emitting element 430c, and a solid sealing structure is applied to the display device 400.

[0221] The light-emitting element 430b and the light-emitting element 430c each have a conductive layer 411a, a conductive layer 411b, and a conductive layer 411c as pixel electrodes. The conductive layer 411b is reflective to visible light and functions as a reflective electrode. The conductive layer 411c is transparent to visible light and functions as an optical adjustment layer.

[0222] The conductive layer 411a is connected to a conductive layer 222b of the transistor 210 through an opening provided in the insulating layer 214. The transistor 210 has a function of controlling the driving of a light-emitting element.

[0223] An EL layer 412G or an EL layer 412B is provided to cover the pixel electrode. An insulating layer 421 is provided in contact with the side surfaces of the EL layer 412G and the EL layer 412B, and a resin layer 422 is provided to fill the recesses in the insulating layer 421. A layer 424 is provided between the EL layer 412G and the insulating layer 421, and between the EL layer 412B and the insulating layer 421, respectively. A common layer 414, a common electrode 413, and a protective layer 416 are provided to cover the EL layer 412G and the EL layer 412B.

[0224] Light emitted from the light-emitting element is emitted toward the substrate 452. The substrate 452 is preferably made of a material that is highly transparent to visible light.

[0225] The transistor 202 and the transistor 210 are both formed over a substrate 451. These transistors can be manufactured using the same material and through the same process.

[0226] The substrate 453 and the insulating layer 212 are bonded together by an adhesive layer 455 .

[0227] In a method for manufacturing the display device 400, for example, a formation substrate provided with the insulating layer 212, the transistors, the light-emitting elements, and the like is first bonded to a substrate 454 with an adhesive layer 442. Then, the formation substrate is peeled off, and a substrate 453 is attached to the exposed surface, so that the components formed on the formation substrate are transferred to the substrate 453. The substrate 453 and the substrate 454 each preferably have flexibility. This can increase the flexibility of the display device 400.

[0228] The insulating layer 212 can be formed using the inorganic insulating film that can be used for the insulating layer 211 and the insulating layer 215 .

[0229] A connection portion 204 is provided in a region of the substrate 453 where the substrate 454 does not overlap. In the connection portion 204, a wiring 465 is electrically connected to an FPC 472 via a conductive layer 466 and a connection layer 242. The conductive layer 466 can be obtained by processing the same conductive film as the pixel electrode. This allows the connection portion 204 and the FPC 472 to be electrically connected via the connection layer 242.

[0230] The transistor 202 and the transistor 210 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a semiconductor layer 231 including a channel formation region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 functioning as a gate insulating layer, a conductive layer 223 functioning as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located between the conductive layer 223 and the channel formation region 231i.

[0231] The conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through an opening provided in the insulating layer 215. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0232] 19A shows an example in which the top surface and side surfaces of the semiconductor layer are covered with an insulating layer 225. The conductive layer 222a and the conductive layer 222b are connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215, respectively.

[0233] 19B , the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 but does not overlap with the low-resistance region 231n. For example, the insulating layer 225 is processed using the conductive layer 223 as a mask, thereby manufacturing the structure shown in FIG. 19B . In FIG. 19B , the insulating layer 215 is provided to cover the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and the conductive layer 222b are connected to the low-resistance region 231n through openings in the insulating layer 215. Furthermore, an insulating layer 218 may be provided to cover the transistor 209.

[0234] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0235] The transistor 202 and the transistor 210 have a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected to a transistor and the same signal may be supplied to the two gates to drive the transistor. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential for controlling the threshold voltage to one of the two gates and a potential for driving the other.

[0236] The crystallinity of a semiconductor material used for a semiconductor layer of a transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystal semiconductor, and a semiconductor having crystallinity other than single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single-crystal semiconductor or a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0237] The semiconductor layer of the transistor preferably includes a metal oxide (also referred to as an oxide semiconductor). That is, the display device of this embodiment preferably includes a transistor using a metal oxide for a channel formation region (hereinafter referred to as an OS transistor).

[0238] The band gap of the metal oxide used for the semiconductor layer of the transistor is preferably 2 eV or more, more preferably 2.5 eV or more. Use of a metal oxide with a wide band gap can reduce the off-state current of the OS transistor.

[0239] The metal oxide preferably contains at least indium or zinc, and more preferably contains indium and zinc. For example, the metal oxide preferably contains indium, M (wherein 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.

[0240] Alternatively, the semiconductor layer of the transistor may include silicon, such as amorphous silicon or crystalline silicon (e.g., low-temperature polysilicon or single-crystal silicon).

[0241] The transistors included in the circuit 464 may have the same structure as or different from the transistors included in the display portion 462. The transistors included in the circuit 464 may all have the same structure or may have two or more types of structures. Similarly, the transistors included in the display portion 462 may all have the same structure or may have two or more types of structures.

[0242] At least one insulating layer covering the transistor is preferably made of a material that is resistant to the diffusion of impurities such as water and hydrogen. This allows the insulating layer to function as a barrier layer. With this structure, it is possible to effectively prevent impurities from diffusing into the transistor from the outside, thereby improving the reliability of the display device.

[0243] It is preferable to use an inorganic insulating film for each of the insulating layers 211, 212, 215, 218, and 225. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Alternatively, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used. Two or more of the above-described inorganic insulating films may be stacked.

[0244] An organic insulating film is suitable for the insulating layer 214 that functions as a planarizing layer. Examples of materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0245] Various optical members can be disposed along the inner or outer surface of substrate 454. Examples of optical members include a light-shielding layer, a polarizing plate, a retardation plate, a light-diffusing layer (such as a diffusion film), an anti-reflection layer, a microlens array, and a light-collecting film. In addition, the outer surface of substrate 454 may be provided with, for example, an antistatic film that prevents dust from adhering, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that prevents scratches from occurring during use, or an impact-absorbing layer.

[0246] By providing the protective layer 416 that covers the light-emitting element, impurities such as water can be prevented from entering the light-emitting element, and the reliability of the light-emitting element can be improved.

[0247] 19A shows a connection portion 228. The common electrode 413 and the wiring are electrically connected at the connection portion 228. FIG. 19A shows an example in which the same layered structure as that of the pixel electrode is applied to the wiring.

[0248] The substrate 453 and the substrate 454 can each be made of, for example, glass, quartz, ceramics, sapphire, resin, metal, alloy, or semiconductor. A material that transmits light is used for the substrate on the side from which light from the light-emitting element is extracted. Using a flexible material for the substrate 453 and the substrate 454 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used for the substrate 453 or the substrate 454.

[0249] The substrates 453 and 454 may each be made of, for example, a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), a polyacrylonitrile resin, an acrylic resin, a polyimide resin, a polymethyl methacrylate resin, a polycarbonate (PC) resin, a polyethersulfone (PES) resin, a polyamide resin (for example, nylon or aramid), a polysiloxane resin, a cycloolefin resin, a polystyrene resin, a polyamideimide resin, a polyurethane resin, a polyvinyl chloride resin, a polyvinylidene chloride resin, a polypropylene resin, a polytetrafluoroethylene (PTFE) resin, an ABS resin, or a cellulose nanofiber. One or both of the substrates 453 and 454 may be made of glass having a thickness sufficient to provide flexibility.

[0250] The adhesive layer may be made of various curable adhesives, such as a photo-curable adhesive (e.g., an ultraviolet-curable adhesive), a reactive curable adhesive, a thermosetting adhesive, or an anaerobic adhesive. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. Materials with low moisture permeability, such as epoxy resin, are particularly preferred. Two-component resins may also be used. Alternatively, adhesive sheets may also be used.

[0251] The connection layer 242 may be, for example, an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP).

[0252] Materials that can be used for the gate, source, and drain of a transistor as well as conductive layers such as various wirings and electrodes that constitute a display device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys containing these metals as main components, etc. Films containing these materials can be used as a single layer or a stacked layer structure.

[0253] Examples of light-transmitting conductive materials include conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, as well as graphene. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metal materials, may be used. Alternatively, nitrides of such metal materials (e.g., titanium nitride) may be used. When using metal materials or alloy materials (or their nitrides), it is preferable to thin the metal materials thin enough to have light-transmitting properties. A stacked film of the above materials may also be used as the conductive layer. For example, a stacked film of an alloy of silver and magnesium and indium tin oxide is preferable because it can enhance conductivity. These materials may also be used for conductive layers, such as various wirings and electrodes, constituting display devices, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) of light-emitting elements.

[0254] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resins and epoxy resins, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0255] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0256] Embodiment 4 In this embodiment, a light-emitting element (also referred to as a light-emitting device) that can be used for a display device that is one embodiment of the present invention will be described.

[0257] In this specification, etc., a device fabricated using a metal mask or FMM (fine metal mask or high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in this specification, etc., a device fabricated without using a metal mask or FMM may be referred to as a device with an MML (metal maskless) structure.

[0258] In this specification and the like, a structure in which light-emitting layers are separately formed for light-emitting devices that emit light of each color (here, blue (B), green (G), and red (R)), or a structure in which light-emitting layers are separately painted, may be referred to as an SBS (Side By Side) structure. In this specification and the like, a light-emitting device that can emit white light may be referred to as a white light-emitting device. In addition, a white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0259] [Light-Emitting Device] Light-emitting devices can be broadly divided into single structures and tandem structures. A single-structure device has one light-emitting unit between a pair of electrodes. The light-emitting unit includes one or more light-emitting layers. To obtain white light emission with a single structure, two light-emitting layers may be selected so that the colors of light emitted by each of the two light-emitting layers are complementary to each other. For example, by making the color of light emitted by the first light-emitting layer and the color of light emitted by the second light-emitting layer complementary to each other, a configuration that emits white light as a whole can be obtained. Furthermore, when white light emission is obtained using three or more light-emitting layers, the colors of light emitted by the three or more light-emitting layers may be combined to form a configuration that allows the light-emitting device as a whole to emit white light.

[0260] A tandem-structure device has multiple light-emitting units between a pair of electrodes. Each light-emitting unit includes one or more light-emitting layers. By using light-emitting layers that emit light of the same color in each light-emitting unit, the brightness per given current can be increased, and the device can be made more reliable than a single-structure light-emitting device. To obtain white light emission in a tandem structure, the light from the light-emitting layers of the multiple light-emitting units can be combined to obtain white light emission. The combination of light-emitting colors that can produce white light emission is the same as in the single-structure configuration. In a tandem-structure device, it is preferable to provide an intermediate layer, such as a charge-generating layer, between the multiple light-emitting units.

[0261] When comparing a white light-emitting device with a light-emitting device having an SBS structure, the light-emitting device with an SBS structure can consume less power than the white light-emitting device, and the manufacturing process of the white light-emitting device is simpler than that of the light-emitting device having an SBS structure, so the manufacturing cost can be lower and the manufacturing yield can be higher.

[0262] 20A , the light-emitting device includes an EL layer 790 between a pair of electrodes (a lower electrode 791 and an upper electrode 792). The EL layer 790 can be configured with a plurality of layers, such as a layer 720, a light-emitting layer 711, and a layer 730. The layer 720 can include, for example, a layer containing a substance with high electron injection properties (electron injection layer) and a layer containing a substance with high electron transport properties (electron transport layer). The light-emitting layer 711 includes, for example, a light-emitting compound. The layer 730 can include, for example, a layer containing a substance with high hole injection properties (hole injection layer) and a layer containing a substance with high hole transport properties (hole transport layer).

[0263] A structure including the layer 720, the light-emitting layer 711, and the layer 730 provided between a pair of electrodes can function as a single light-emitting unit. In this specification and the like, the structure of Fig. 20A is called a single structure.

[0264] Specifically, the light-emitting device shown in FIG. 20B has layers 730-1 and 730-2, a light-emitting layer 711, layers 720-1 and 720-2, and an upper electrode 792 on a lower electrode 791. For example, the lower electrode 791 is an anode, and the upper electrode 792 is a cathode. In this case, the layer 730-1 functions as a hole injection layer, the layer 730-2 functions as a hole transport layer, the layer 720-1 functions as an electron transport layer, and the layer 720-2 functions as an electron injection layer. On the other hand, when the lower electrode 791 is a cathode and the upper electrode 792 is an anode, the layer 730-1 functions as an electron injection layer, the layer 730-2 functions as an electron transport layer, the layer 720-1 functions as a hole transport layer, and the layer 720-2 functions as a hole injection layer. This layer structure allows carriers to be efficiently injected into the light-emitting layer 711, thereby increasing the efficiency of carrier recombination within the light-emitting layer 711.

[0265] As shown in FIGS. 20C and 20D, a configuration in which multiple light-emitting layers (light-emitting layer 711, light-emitting layer 712, and light-emitting layer 713) are provided between layer 720 and layer 730 is also a variation of the single structure.

[0266] As shown in Figures 20E and 20F, a configuration in which a plurality of light-emitting units (EL layers 790a, 790b) are connected in series via an intermediate layer (charge generating layer) 740 is referred to as a tandem structure in this specification. The tandem structure may also be referred to as a stack structure. Note that the tandem structure makes it possible to obtain a light-emitting device capable of emitting light with high brightness.

[0267] 20C, light-emitting materials that emit light of the same color, or even the same light-emitting material, may be used for the light-emitting layers 711, 712, and 713. Stacking the light-emitting layers can increase the luminance of emitted light.

[0268] Different light-emitting materials may be used for the light-emitting layer 711, the light-emitting layer 712, and the light-emitting layer 713. Light-emitting materials may be used that can obtain white light by combining the colors of light emitted from the light-emitting layer 711, the light-emitting layer 712, and the light-emitting layer 713. Fig. 20D shows an example in which a colored layer 795 that functions as a color filter is provided. When white light passes through the color filter, light of a desired color can be obtained.

[0269] 20E, the light-emitting layer 711 and the light-emitting layer 712 may be made of light-emitting materials that emit light of the same color. Alternatively, the light-emitting layer 711 and the light-emitting layer 712 may be made of light-emitting materials that emit light of different colors. When the color of light emitted by the light-emitting layer 711 and the color of light emitted by the light-emitting layer 712 are complementary colors, white light is obtained. FIG. 20F shows an example in which a colored layer 795 is further provided.

[0270] 20C, 20D, 20E, and 20F, the layer 720 and the layer 730 may have a laminated structure consisting of two or more layers, as shown in FIG. 20B.

[0271] 20D, light-emitting layers 711, 712, and 713 may be made of light-emitting materials that emit the same color. Similarly, in FIG. 20F, light-emitting layers 711 and 712 may be made of light-emitting materials that emit the same color. In this case, by applying a color conversion layer instead of colored layer 795, light of a desired color different from the color of light emitted by the light-emitting material can be obtained. For example, by using a light-emitting material that emits blue light in each light-emitting layer and transmitting the blue light through the color conversion layer, light with a wavelength longer than blue (e.g., red or green) can be obtained. For example, a fluorescent material, a phosphorescent material, or quantum dots can be used as the color conversion layer.

[0272] The light-emitting device can emit light of, for example, red, green, blue, cyan, magenta, yellow, or white, depending on the material that makes up the EL layer 790. Furthermore, the color purity can be further improved by providing the light-emitting device with a microcavity structure.

[0273] A light-emitting device that emits white light may have a structure in which two or more types of light-emitting materials are contained in the light-emitting layer, or two or more light-emitting layers each containing a different light-emitting material may be stacked. In this case, light-emitting materials may be selected so that the colors of light emitted by the light-emitting materials are combined to produce a white light emission from the light-emitting device as a whole.

[0274] [Light-Emitting Device] Here, a specific example of the configuration of the light-emitting device will be described.

[0275] The light-emitting device has at least a light-emitting layer. The light-emitting device may further have, as a layer other than the light-emitting layer, a layer containing, for example, a substance with high hole-injection property, a substance with high hole-transport property, a hole-blocking material, a substance with high electron-transport property, an electron-blocking material, a substance with high electron-injection property, an electron-blocking material, or a bipolar substance (a substance with high electron-transport property and high hole-transport property).

[0276] The light-emitting device can be made of either a low-molecular-weight compound or a high-molecular-weight compound. The light-emitting device may also contain an inorganic compound. The layers constituting the light-emitting device can be formed by, for example, a vapor deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, or a coating method.

[0277] For example, a light emitting device can include one or more of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0278] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a material with high hole injection properties, such as an aromatic amine compound and a composite material containing a hole transport material and an acceptor material (electron acceptor material).

[0279] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light emitting layer. The hole transport layer is a layer that contains a hole transport material. The hole transport material is a material having a concentration of 1×10 −６ cm ２ A substance having a hole mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, for example, a material having a high hole transporting property, such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, or a furan derivative), or an aromatic amine (a compound having an aromatic amine skeleton), is preferred.

[0280] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light emitting layer. The electron transport layer is a layer that contains an electron transporting material. The electron transporting material is a material having a molecular weight of 1×10 −６ cm ２ / Vs or more is preferred. Note that other materials can also be used as long as they have a higher electron transporting property than holes. Examples of the electron-transporting material include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, and metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0281] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a material with high electron injection properties. Examples of the material with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the material with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0282] The electron injection layer may be formed of, for example, lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ２ ), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), lithium oxide (LiO ｘ), alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. The electron injection layer may have a stacked structure of two or more layers. For example, the stacked structure may have a structure in which lithium fluoride is used in the first layer and ytterbium is provided in the second layer.

[0283] Alternatively, a material having electron transport properties may be used for the electron injection layer. For example, a compound having an unshared electron pair and an electron-deficient heteroaromatic ring may be used as the material having electron transport properties. Specifically, a compound having at least one of a pyridine ring, a diazine ring (a pyrimidine ring, a pyrazine ring, or a pyridazine ring), and a triazine ring may be used.

[0284] The organic compound having an unshared electron pair preferably has a lowest unoccupied molecular orbital (LUMO) level of −3.6 eV to −2.3 eV. Generally, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by, for example, cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, or inverse photoelectron spectroscopy.

[0285] Examples of organic compounds having unshared electron pairs include 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), diquinoxalino[2,3-a:2′,3′-c]phenazine (abbreviation: HATNA), and 2,4,6-tris[3′-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz). NBPhen has a higher glass transition point (Tg) and is more heat resistant than BPhen.

[0286] The light-emitting layer is a layer containing a light-emitting substance. The light-emitting layer can contain one or more light-emitting substances. As the light-emitting substance, for example, a substance that emits light of blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. Furthermore, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0287] Examples of the light-emitting material include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0288] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0289] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton; organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand; platinum complexes; and rare earth metal complexes.

[0290] The light-emitting layer may contain one or more organic compounds (e.g., a host material, an assist material, etc.) in addition to a light-emitting substance (guest material). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material can be used. Furthermore, as the one or more organic compounds, a bipolar material or a TADF material can be used.

[0291] The light-emitting layer preferably includes, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. This configuration allows for efficient emission using Exciplex-Triple Energy Transfer (ExTET), which is energy transfer from the exciplex to the light-emitting material (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, the energy transfer becomes smooth, allowing for efficient emission. This configuration allows for high efficiency, low-voltage operation, and a long life of the light-emitting device to be achieved simultaneously.

[0292] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0293] Embodiment 5 In this embodiment, electronic devices to which a display device according to one embodiment of the present invention can be applied will be described.

[0294] A display device according to one embodiment of the present invention can be applied to a display portion of an electronic device. Therefore, one embodiment of the present invention can realize an electronic device with high display quality. Alternatively, one embodiment of the present invention can realize an electronic device with extremely high resolution. Alternatively, one embodiment of the present invention can realize an electronic device with high reliability.

[0295] Examples of electronic devices using a display device or the like according to one embodiment of the present invention include display devices such as televisions and monitors, lighting devices, desktop or notebook personal computers, word processors, and DVD (Digital Versatile Examples of the equipment include image playback devices that play back still images or videos stored on recording media such as a portable CD player, a radio, a tape recorder, a headphone stereo, a stereo, a table clock, a wall clock, a cordless telephone handset, a transceiver, a car telephone, a mobile phone, a personal digital assistant, a tablet terminal, a portable game machine, a fixed game machine such as a pachinko machine, a calculator, an electronic organizer, an electronic book terminal, an electronic translator, a voice input device, a video camera, a digital still camera, an electric shaver, a high-frequency heating device such as a microwave oven, an electric rice cooker, an electric washing machine, an electric vacuum cleaner, a water heater, an electric fan, a hair dryer, an air conditioning equipment such as an air conditioner, a humidifier, a dehumidifier, a dishwasher, a dish dryer, a clothes dryer, a futon dryer, an electric refrigerator, an electric freezer, an electric refrigerator-freezer, a DNA storage freezer, a flashlight, a tool such as a chainsaw, a smoke detector, and a medical device such as a dialysis machine. Further examples include industrial equipment such as emergency lights, traffic lights, conveyor belts, elevators, escalators, industrial robots, power storage systems, and power storage devices for power leveling and smart grids. Furthermore, mobile objects propelled by fuel-powered engines or electric motors powered by power from power storage devices may also be included in the category of electronic devices. Examples of such mobile objects include electric vehicles (EVs), hybrid vehicles (HVs) equipped with both internal combustion engines and electric motors, plug-in hybrid vehicles (PHVs), tracked vehicles in which the tires and wheels of these vehicles are replaced with tracks, mopeds including electrically assisted bicycles, motorcycles, electric wheelchairs, golf carts, small or large ships, submarines, helicopters, aircraft, rockets, artificial satellites, space probes, planetary probes, and spaceships.

[0296] An electronic device according to one embodiment of the present invention may include a secondary battery. Preferably, the secondary battery can be charged using contactless power transmission.

[0297] Examples of secondary batteries include lithium ion secondary batteries, nickel-metal hydride batteries, nickel-cadmium batteries, organic radical batteries, lead-acid batteries, air secondary batteries, nickel-zinc batteries, and silver-zinc batteries.

[0298] An electronic device according to one embodiment of the present invention may include an antenna. By receiving a signal through the antenna, images, information, and the like can be displayed on a display portion. When the electronic device includes an antenna and a secondary battery, the antenna may be used for contactless power transmission.

[0299] An electronic device according to one embodiment of the present invention may have a sensor (e.g., a sensor having the function of measuring force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared light, etc.).

[0300] An electronic device according to one embodiment of the present invention can have various functions, such as a function to display various information (e.g., still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date, time, etc., a function to execute various software (programs), a wireless communication function, or a function to read out programs or data recorded on a recording medium.

[0301] Furthermore, electronic devices having multiple display units can have a function of mainly displaying image information on some of the display units and mainly displaying text information on other display units, or a function of displaying a stereoscopic image by displaying images taking parallax into account on the multiple display units. Furthermore, electronic devices having an image receiving unit can have a function of capturing still images or videos, a function of automatically or manually correcting the captured images, a function of saving the captured images in a recording medium (external or built into the electronic device), or a function of displaying the captured images on the display unit. Note that the functions of the electronic device according to one embodiment of the present invention are not limited to these. The electronic device according to one embodiment of the present invention can have various functions.

[0302] A display device according to one embodiment of the present invention can display high-resolution images. Therefore, the display device can be particularly suitably used in portable electronic devices, wearable electronic devices, e-book readers, etc. For example, the display device can be suitably used in xR devices such as VR devices and AR devices.

[0303] FIG. 21A is a diagram showing the appearance of the camera 8000 with the viewfinder 8100 attached.

[0304] The camera 8000 includes a housing 8001, a display unit 8002, operation buttons 8003, a shutter button 8004, and the like. A detachable lens 8006 is attached to the camera 8000. Note that the lens 8006 and the housing of the camera 8000 may be integrated together.

[0305] The camera 8000 can capture an image by pressing a shutter button 8004 or touching a display portion 8002 that functions as a touch panel.

[0306] The housing 8001 has a mount with electrodes, and can be connected to a finder 8100 as well as, for example, a strobe device.

[0307] The finder 8100 includes a housing 8101, a display portion 8102, a button 8103, and the like.

[0308] The housing 8101 is attached to the camera 8000 by a mount that engages with the mount of the camera 8000. The viewfinder 8100 can display, for example, an image received from the camera 8000 on a display portion 8102.

[0309] The button 8103 has a function as, for example, a power button.

[0310] A display device according to one embodiment of the present invention can be applied to a display portion 8002 of a camera 8000 and a display portion 8102 of a finder 8100. Note that the finder 8100 may be built in the camera 8000.

[0311] FIG. 21B is a diagram showing the appearance of the head-mounted display 8200.

[0312] The head-mounted display 8200 includes a mounting portion 8201, a lens 8202, a main body 8203, a display portion 8204, and a cable 8205. The mounting portion 8201 has a built-in battery 8206.

[0313] The cable 8205 has a function of supplying power from a battery 8206 to the main body 8203. The main body 8203 includes, for example, a wireless receiver or the like and can display received video information on a display portion 8204. The main body 8203 also includes, for example, a camera and can use information on the movement of the user's eyeballs or eyelids as an input means.

[0314] The wearing unit 8201 may have a function of recognizing the line of sight by providing a plurality of electrodes at positions that come into contact with the user, the electrodes being capable of detecting a current that flows in association with the movement of the user's eyeballs. The wearing unit 8201 may also have a function of monitoring the user's pulse rate based on the current that flows through the electrodes. The wearing unit 8201 may also have various sensors, such as a temperature sensor, a pressure sensor, or an acceleration sensor. The head-mounted display 8200 may have a function of displaying biometric information of the user on the display unit 8204 or a function of changing an image displayed on the display unit 8204 in accordance with the movement of the user's head.

[0315] A display device according to one embodiment of the present invention can be applied to the display portion 8204.

[0316] 21C to 21E are diagrams showing the appearance of a head mounted display 8300. The head mounted display 8300 includes a housing 8301, a display portion 8302, a band-shaped fixture 8304, and a pair of lenses 8305.

[0317] The user can view the display on the display portion 8302 through the lens 8305. Note that the head-mounted display 8300 is preferably configured such that the display portion 8302 is curved, for example, because the user can feel a high sense of presence. Furthermore, for example, by viewing different images displayed in different regions of the display portion 8302 through the lens 8305, it is possible to perform, for example, three-dimensional display using parallax. Note that the present invention is not limited to a configuration in which one display portion 8302 is provided, and for example, two display portions 8302 may be provided, with one display portion being provided for each eye of the user.

[0318] A display device according to one embodiment of the present invention can be applied to the display portion 8302. The display device according to one embodiment of the present invention can also achieve extremely high resolution. For example, even when the display is enlarged and viewed using the lens 8305 as shown in FIG. 21E , the pixels are hardly visible to the user. That is, the display portion 8302 can be used to allow the user to view a highly realistic image.

[0319] 21F is a diagram showing the appearance of a goggle-type head-mounted display 8400. The head-mounted display 8400 includes a pair of housings 8401, an attachment portion 8402, and a cushioning member 8403. A display portion 8404 and a lens 8405 are provided in each of the pair of housings 8401. The pair of display portions 8404 can display different images from each other, thereby enabling 3D display using parallax.

[0320] A user can view the display on the display portion 8404 through the lens 8405. The lens 8405 has a focus adjustment mechanism, and the position of the lens 8405 can be adjusted according to the user's eyesight. The display portion 8404 is preferably a square or a horizontally long rectangle. This can enhance the sense of realism.

[0321] The wearing portion 8402 preferably has plasticity and elasticity so that it can be adjusted according to the size of the user's face and does not slip off. Furthermore, a portion of the wearing portion 8402 preferably has a vibration mechanism that functions as a bone conduction earphone, for example. This allows the user to enjoy video and audio simply by wearing the device, without the need for separate earphones or audio equipment such as a speaker. The housing 8401 may also have a function for outputting audio data via wireless communication, for example.

[0322] The mounting portion 8402 and the buffer member 8403 are portions that come into contact with the user's face (forehead, cheek, etc.). The close contact of the buffer member 8403 with the user's face can prevent light leakage and enhance the sense of immersion. The buffer member 8403 is preferably made of a soft material so that it can be in close contact with the user's face when the user wears the head-mounted display 8400. For example, materials such as rubber, silicone rubber, urethane, or sponge can be used. Furthermore, for example, using a sponge or the like with a surface covered with cloth or leather (natural leather or synthetic leather) can prevent gaps from forming between the user's face and the buffer member 8403, thereby effectively preventing light leakage. Furthermore, using such materials is preferable because they are pleasant to the touch and do not cause the user to feel cold when worn, for example, in cold seasons. It is preferable that components that come into contact with the user's skin, such as the buffer member 8403 or the mounting portion 8402, be removable for easy cleaning or replacement.

[0323] 22A is a diagram showing an example of a television device. A television device 7100 has a display unit 7000 built into a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0324] In FIG. 22A , a display device according to one embodiment of the present invention can be applied to a display portion 7000 .

[0325] 22A can be operated using an operation switch provided on the housing 7101 or a separate remote control 7111. Alternatively, a touch sensor may be provided on the display portion 7000, so that the television set 7100 can be operated by touching the display portion 7000 with a finger or the like. The remote control 7111 may have a display portion that displays information output from the remote control 7111. The television set 7100 can be operated to change channels or change volume using operation keys or a touch panel provided on the remote control 7111. Furthermore, an image displayed on the display portion 7000 can be operated.

[0326] The television device 7100 may be configured to include, for example, a receiver and a modem. The receiver can receive general television broadcasts. By connecting to a wired or wireless communication network via the modem, information communication can be performed in one direction (from a sender to a receiver) or two directions (for example, between a sender and a receiver, or between receivers).

[0327] 22B is a diagram showing an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214. The housing 7211 includes a display portion 7000.

[0328] In FIG. 22B , a display device according to one embodiment of the present invention can be applied to the display portion 7000 .

[0329] 22C and 22D are diagrams showing an example of digital signage.

[0330] 22C includes a housing 7301, a display portion 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, or the like.

[0331] 22D is a diagram showing a digital signage device attached to a cylindrical pole. The digital signage device 7400 has a display unit 7000 provided along the curved surface of the pole 7401.

[0332] 22C and 22D, a display device according to one embodiment of the present invention can be applied to the display portion 7000.

[0333] The larger the display unit 7000 of the digital signage 7300 or the digital signage 7400, the more information can be provided at one time. Furthermore, the larger the display unit 7000, the more easily it attracts people's attention, which can increase the advertising effectiveness of, for example, advertisements.

[0334] Furthermore, it is preferable that the digital signage 7300 or the digital signage 7400 has a touch panel applied to the display unit 7000. This not only allows images or videos to be displayed on the display unit 7000 but also allows the user to intuitively operate it. Furthermore, when used to provide information such as route information or traffic information, intuitive operation can improve usability.

[0335] 22C and 22D , the digital signage 7300 or the digital signage 7400 is preferably capable of wirelessly linking with, for example, an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411. Furthermore, the display on the display unit 7000 can be switched by operating the information terminal 7311 or the information terminal 7411.

[0336] Furthermore, the digital signage 7300 or the digital signage 7400 can also run a game using the screen of the information terminal 7311 or the information terminal 7411 as an operation means (controller), thereby allowing an unspecified number of users to simultaneously participate in and enjoy the game.

[0337] 22E illustrates an example of an information terminal. The information terminal 7550 includes a housing 7551, a display portion 7552, a microphone 7557, a speaker portion 7554, a camera 7553, an operation switch 7555, and the like. A display device according to one embodiment of the present invention can be used for the display portion 7552. The display portion 7552 can function as a touch panel. The information terminal 7550 can include an antenna, a battery, and the like inside the housing 7551. The information terminal 7550 can be used as, for example, a smartphone, a mobile phone, a tablet information terminal, a tablet personal computer, an e-book reader, or the like.

[0338] 22F is a diagram showing an example of a wristwatch-type information terminal. The information terminal 7660 includes a housing 7661, a display portion 7662, a band 7663, a buckle 7664, operation switches 7665, and an input / output terminal 7666. The information terminal 7660 may also include, for example, an antenna and a battery inside the housing 7661. The information terminal 7660 can execute various applications such as mobile phone calls, e-mail, text browsing and creation, music playback, internet communication, and computer games.

[0339] The information terminal 7660 also includes a touch sensor on the display portion 7662, allowing it to be operated by touching the screen with a finger or a stylus, for example. For example, an application can be started by touching an icon 7667 displayed on the display portion 7662. The operation switch 7665 can have various functions, such as time setting, power on / off operation, wireless communication on / off operation, silent mode activation / deactivation, or power saving mode activation / deactivation. For example, the functions of the operation switch 7665 can be set by an operating system incorporated in the information terminal 7660.

[0340] The information terminal 7660 can also perform short-range wireless communication according to a communication standard. For example, hands-free conversation is also possible by mutual communication with a wireless headset. The information terminal 7660 can also transmit and receive data to and from other information terminals via the input / output terminal 7666. Charging can also be performed via the input / output terminal 7666. Note that charging may also be performed by wireless power supply without using the input / output terminal 7666.

[0341] 23A is a diagram illustrating the appearance of an automobile 9700. FIG. 23B is a diagram illustrating a driver's seat of the automobile 9700. The automobile 9700 includes a body 9701, wheels 9702, a dashboard 9703, and lights 9704. A display device according to one embodiment of the present invention can be used for the display portion of the automobile 9700, for example. For example, the display device according to one embodiment of the present invention can be applied to each of display portions 9710 to 9715 illustrated in FIG. 23B.

[0342] The display portion 9710 and the display portion 9711 are display devices provided on a windshield of an automobile. The display device according to one embodiment of the present invention can be a so-called see-through display device, in which the other side can be seen through, by forming electrodes of the display device using a light-transmitting conductive material. A see-through display device does not obstruct visibility even when driving the automobile 9700. Therefore, the display device according to one embodiment of the present invention can be installed on the windshield of the automobile 9700. Note that when the display device includes a transistor for driving the display device, for example, the transistor may be a light-transmitting transistor, such as an organic transistor using an organic semiconductor material or a transistor using an oxide semiconductor.

[0343] The display portion 9712 is a display device provided at a pillar portion. For example, by displaying an image from an imaging means provided in the vehicle body 9701 on the display portion 9712, the view blocked by the pillar can be complemented. The display portion 9713 is a display device provided at the dashboard 9703. For example, by displaying an image from an imaging means provided in the vehicle body 9701 on the display portion 9713, the view blocked by the dashboard 9703 can be complemented. That is, the automobile 9700 can complement blind spots and improve safety by displaying images from an imaging means provided in the vehicle body 9701 on the display portions 9712 and 9713. Furthermore, by displaying an image that complements the invisible parts, safety can be confirmed more naturally and without discomfort.

[0344] 24 is a diagram showing the interior of an automobile 9700 that employs bench seats for the driver's seat and passenger seat. The display unit 9721 is a display device provided in the door. For example, by displaying an image from an imaging means provided in the vehicle body 9701 on the display unit 9721, it is possible to complement the view blocked by the door. The display unit 9722 is a display device provided in the steering wheel. The display unit 9723 is a display device provided in the center of the seat surface of the bench seat.

[0345] The display unit 9714, the display unit 9715, or the display unit 9722 can provide the user with various information by displaying, for example, navigation information, driving speed, engine RPM, mileage, remaining fuel, gear status, or air conditioning settings. The display items and layout displayed on the display unit can be changed as appropriate to suit the user's preferences. The information can also be displayed on one or more of the display units 9710 to 9713, the display unit 9721, and the display unit 9723. One or more of the display units 9710 to 9715 and the display units 9721 to 9723 can also be used as lighting devices.

[0346] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0347] 10: display device, 11: pixel, 12: monitor circuit, 13: image processing circuit, 51: wiring, 52: wiring, 53: wiring, 61: light-emitting element, 180A: transistor, 180B: transistor, 180C: transistor, M1: transistor, M2: transistor, M3: transistor, M4: transistor, M5: transistor, M6: transistor, C1: capacitor, C2: capacitor, DL: wiring, ML: wiring, GLa: wiring, GLb: wiring, GLc: wiring, ND1: Node, ND2: node, ND3: node, Vdata: display data, V0: potential, V1: potential, Va: potential, Vc: potential, Ve0: potential, Ve1: potential, Ve2: potential, Ve3: potential, Ve4: potential, T11: period, T12: period, T13: period, T21: period, T22: period, T23: period, T24: period, T31: period, T32: period, T33: period, S01: step, S02: step, S03: step, S04: step, S05: step

Claims

1. A display device correction method comprising a pixel, a first circuit, and a second circuit, wherein the pixel includes a light emitting element, a transistor, and a capacitor, and the transistor has a function of controlling a current supplied to the light emitting element based on a first signal supplied to the pixel. The method includes: performing a first process of obtaining a voltage for correcting a threshold voltage of the transistor and holding the voltage in the capacitor; after completion of the first process, performing a second process in the first circuit of measuring a current flowing through the pixel and generating a second signal based on the current; after completion of the second process, performing a third process in the second circuit of generating the first signal obtained by correcting image data using the second signal; after completion of the third process, performing a fourth process of supplying the first signal to the pixel. A display device correction method.

2. A display device correction method comprising a pixel, a first circuit, and a second circuit, wherein the pixel includes a light emitting element, a transistor, and a capacitor, and the transistor has a function of controlling a current supplied to the light emitting element based on a first signal supplied to the pixel. The method includes: performing a second process in the first circuit of measuring a current flowing through the pixel and generating a second signal based on the current; after completion of the second process, performing a first process of obtaining a voltage for correcting a threshold voltage of the transistor and holding the voltage in the capacitor; after completion of the second process, performing a third process in the second circuit of generating the first signal obtained by correcting image data using the second signal; after completion of the first process and the third process, performing a fourth process of supplying the first signal to the pixel. A display device correction method.

3. In Claim 2, the first process and the third process are performed simultaneously. A display device correction method.

4. In Claim 3, the second process measures a current flowing through the light emitting element. A display device correction method.

5. In Claim 4, the transistor includes a back gate, and the transistor has a function of controlling a threshold voltage of the transistor based on a potential supplied to the back gate, and the first process obtains a voltage between the back gate and a source of the transistor. A display device correction method.

6. In any one of Claims 1 to 5, The fourth process supplies the first signal to the gate of the transistor. Correction method for a display device.