Display device

Abstract

To provide a driving method for a semiconductor device, in which the influence of variation in threshold voltage and variation in mobility of transistors can be reduced.SOLUTION: In a driving method for a semiconductor device including a transistor of an n-channel conductivity type, a switch for controlling the electric connection between a first terminal and a gate of the transistor, a capacitor element electrically connected between a second terminal and the gate of the transistor, and a display element, a first period for holding the sum of a video signal voltage and a voltage according to a threshold voltage of the transistor in the capacitor element, a second period for discharging, through the transistor, charges held in the capacitor element in accordance with the sum of the video signal voltage and the threshold voltage by making the switch conductive, and a third period for supplying current to the display element through the transistor after the second period are provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device, a display device, a light-emitting device, or a driving method thereof. [Background technology]

[0002] In recent years, flat panel displays such as liquid crystal displays (LCDs) have become widely used. However, LCDs have drawbacks such as a narrow viewing angle, a narrow color range, and a slow response time. Therefore, as a display that overcomes these drawbacks, Organic EL (electroluminescence, organic light-emitting diode, or OLED) Research into displays is being actively conducted (Patent Document 1).

[0003] However, organic EL displays require a device to control the current flowing through the organic EL element. The problem was that the current characteristics of the transistors varied from pixel to pixel. If the current flowing through the EL element (i.e., the current flowing through the transistor) varies, the OLED element The brightness of the screen also varies, resulting in an uneven display. Methods for correcting variations in low voltages have been studied (Patent Documents 2 to 6).

[0004] However, even if the variation in the threshold voltage of the transistor is corrected, the mobility of the transistor If there is variation, the current flowing through the organic EL element will also vary, resulting in image unevenness. Therefore, a method to correct not only the variation in the threshold voltage of the transistor but also the variation in mobility was investigated. This has been investigated (Patent Documents 7 to 8). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-216110 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-202833 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-31630 [Patent Document 4] Japanese Patent Application Laid-Open No. 2005-345722 [Patent Document 5] Japanese Patent Application Laid-Open No. 2007-148129 [Patent Document 6] International Publication No. 2006 / 060902 Pamphlet [Patent Document 7] JP 2007-148128 A (paragraph

[0098] ) [Patent Document 8] JP 2007-310311 A (paragraph

[0026] ) Summary of the Invention [Problem to be solved by the invention]

[0006] In the techniques disclosed in Patent Documents 7 and 8, a video signal is input to a pixel. However, the compensation for the variation in the mobility of the transistors is performed, which causes problems.

[0007] For example, to correct the mobility variation while inputting a video signal, a different image signal can be displayed during that time. It is usually impossible to input a video signal directly. Once the size and other factors are determined, the period during which the video signal is input to each pixel (the so-called one gate selection period or The maximum value of the mobility variation during one gate selection period is also determined. As the correction period increases, other processing (such as inputting video signals and obtaining threshold voltages) can be performed more efficiently. Therefore, in a pixel, various processes are performed during one gate selection period. As a result, the processing time is insufficient and accurate processing cannot be performed. Or, the mobility variation may be reduced due to the insufficient time for correction. The correction of the above will be insufficient.

[0008] Furthermore, as the number of pixels and frame frequency increase, or as the screen size increases, Therefore, the time required for inputting a video signal to a pixel becomes shorter. This means that there is no longer enough time to ensure the accuracy of the calculations and to correct the variations in mobility. cormorant.

[0009] Alternatively, when correcting the mobility variation while inputting a video signal, the mobility variation The correction of the video signal waveform is easily affected by distortion. When the margin is large or small, the degree of mobility correction varies. , accurate correction is not possible.

[0010] Alternatively, when correcting the mobility variation while inputting a video signal to the pixel, the pixel is driven in a dot sequential manner. In point-sequential driving, a video signal is input to the pixels of a certain row. When this is done, the video signal is not input to all pixels in that row at the same time, but is input one pixel at a time. Therefore, the length of the period during which the video signal is input varies for each pixel. Therefore, when correcting the mobility variation while inputting a video signal, Since the correction period for the mobility variation differs for each pixel, the amount of correction also differs for each pixel. Therefore, it is not possible to perform the correction correctly. When correcting for variations in pixel density, the signal is sent to all pixels in the row at the same time, rather than being driven point-sequentially. It is necessary to perform line sequential driving to input the signal.

[0011] Furthermore, when line sequential driving is performed, the source signal line driving circuit (also called video signal line driver, source driver, or data driver) has a complex configuration For example, the source signal line driver circuit for line sequential driving is composed of a DA converter, an analog In many cases, circuits such as buffers and latch circuits are required. However, analog buffers are It is often composed of an operational amplifier or a source follower circuit, and the current characteristics of the transistor Therefore, the circuit is made using TFT (thin film transistor). When configuring a transistor, a circuit is required to correct the variations in the current characteristics. The scale of the system becomes larger and the power consumption increases. When TFTs are used as transistors in the pixel area, the pixel area and the signal line driver Therefore, it may be difficult to form the signal line driving circuit on the same substrate. The path must be created using a method separate from the pixel part, which may increase costs. Furthermore, the pixel section and the signal line driver circuit can be mounted on a COG (chip on glass) or or TAB (Tape Automated Bonding) etc. This can cause poor contact and reduce reliability.

[0012] In view of this, one embodiment of the present invention is to reduce the influence of variations in threshold voltage of transistors. Another object of one embodiment of the present invention is to reduce the influence of variations in mobility of transistors. Another object of one embodiment of the present invention is to reduce variations in current characteristics of transistors. Another object of the present invention is to reduce the influence of noise. Another object of one embodiment of the present invention is to reduce variations in threshold voltage. Another object of the present invention is to provide a long correction period to reduce the influence of the noise. One aspect of the present invention aims to secure a long correction period for reducing the influence of variations in mobility. Another embodiment of the present invention is to make the video signal less susceptible to distortion of the waveform of the video signal. Another object of one embodiment of the present invention is to realize a method for manufacturing a liquid crystal display device using not only line-sequential driving but also point-sequential driving. Another object of one embodiment of the present invention is to provide a pixel and a driver circuit in the same device. Another object of one embodiment of the present invention is to form a semiconductor device over a substrate. Another object of one embodiment of the present invention is to reduce manufacturing costs. Another aspect of the present invention is to reduce the possibility of poor contact at a connection portion of a wiring. The description of these issues does not preclude the existence of other issues. However, it is not necessary for one embodiment of the present invention to solve all of the above problems. [Means for solving the problem]

[0013] One embodiment of the present invention is a transistor having n-channel conductivity and a gate electrode of the transistor. a switch for controlling a conductive state between the first terminal of the transistor and the second terminal of the transistor; a capacitor electrically connected between the gate of the display element and the second terminal of the transistor; a driving method of a semiconductor device having a capacitance element, a first period in which the sum of the voltage according to the voltage and the video signal voltage is maintained; and a second period in which the switch is in a conductive state. By this, the charge held in the capacitance element is changed according to the sum of the video signal voltage and the threshold voltage. a second period of time during which the transistor discharges; and after the second period of time, the transistor discharges. and a third period in which a current is supplied to the display element.

[0014] One embodiment of the present invention is a transistor having n-channel conductivity and a gate electrode of the transistor. a switch for controlling a conductive state between the first terminal of the transistor and the second terminal of the transistor; a capacitor electrically connected between the gate of the display element and the second terminal of the transistor; a driving method of a semiconductor device having a capacitance element, a first period in which a voltage according to the threshold voltage of the transistor is held; a second period in which the sum of the voltage and the video signal voltage is maintained; and a second period in which the switch is in a conducting state. The charge held in the capacitance element is transferred to the transistor in accordance with the sum of the video signal voltage and the threshold voltage. A third period of time in which the transistor discharges, and after the third period of time, the transistor discharges, and a fourth period in which a current is supplied to the element.

[0015] One embodiment of the present invention is a transistor having n-channel conductivity and a gate electrode of the transistor. a switch for controlling a conductive state between the first terminal of the transistor and the second terminal of the transistor; a capacitor electrically connected between the gate of the display element and the second terminal of the transistor; and a driving method of a semiconductor device having the above-mentioned. a first period for holding a voltage corresponding to the threshold voltage of the transistor in the capacitor; 2, and the voltage corresponding to the threshold voltage of the transistor and the video signal voltage are applied to the capacitor. The third period is for holding the sum of the video signal voltage and the The charge held in the capacitance element is discharged through the transistor according to the sum of the threshold voltages. After the fourth period, a fourth period is generated to supply a current to the display element through the transistor. and a driving method of a semiconductor device having the period.

[0016] The switch may take various forms, for example, an electrical switch. There are various types of switches, such as switches and mechanical switches. In other words, anything that can control the flow of current is sufficient. There is no particular limitation. For example, a transistor (e.g., a bipolar transistor) can be used as a switch. transistors, MOS transistors, etc.), diodes (e.g., PN diodes, P IN diode, Schottky diode, MIM (Metal Insulator Metal diode, MIS (Metal Insulator Semiconductor) diodes, diode-connected transistors, etc. Alternatively, a logic circuit that combines these can be used as a switch.

[0017] Examples of mechanical switches include digital micromirror devices (DMDs), There are switches that use MEMS (microelectromechanical systems) technology. The switch has an electrode that can be moved mechanically, and the movement of the electrode The transistor operates by controlling conduction and non-conduction.

[0018] In addition, CMOS transistors are used to implement both N-channel and P-channel transistors. A switch of the type may be used as the switch.

[0019] When it is explicitly stated that A and B are connected, it means that A and B are electrically connected. A and B are functionally connected, A and B are directly connected, Here, A and B are objects (e.g., devices, elements, circuits) , wiring, electrodes, terminals, conductive films, layers, etc.). Therefore, a predetermined connection relationship, For example, the present invention is not limited to the connection relationships shown in the drawings or text, but may be modified to include the connection relationships shown in the drawings or text. This also includes matters other than those in charge.

[0020] For example, if A and B are electrically connected, the electrical connection between A and B can be The elements to be considered (e.g., switches, transistors, capacitance elements, inductors, resistance elements, One or more electrodes (such as a diode) may be connected between A and B. Alternatively, A and B may In the case of functional connection, a circuit that allows the functional connection between A and B (e.g. , logic circuits (inverters, NAND circuits, NOR circuits, etc.), signal conversion circuits (DA conversion circuits circuits, AD conversion circuits, gamma correction circuits, etc.), potential level conversion circuits (power supply circuits (boosting circuits, voltage sources, current sources, Switching circuits, amplifier circuits (circuits that can increase signal amplitude or current, etc.), operational amplifiers, differential amplifier circuits, source follower circuits, buffer circuits, signal generation circuits, memory circuits, control One or more control circuits may be connected between A and B. For example, Even if there is another circuit between them, if the signal output from A is transmitted to B, then A and B are It is assumed that they are functionally connected.

[0021] In addition, when it is explicitly stated that A and B are electrically connected, it means that A and B are electrically When A and B are directly connected (i.e., when another element or circuit is placed between A and B), A and B are functionally connected (i.e., there is another When A and B are connected functionally across a circuit, and when A and B are connected directly ( (i.e., when A and B are connected without any other element or circuit between them) In other words, when explicitly stating that something is electrically connected, it simply means that it is connected. is the same as if it were expressly stated only that the

[0022] Note that the term "display element," "display device having a display element," "light-emitting element," and "device having a light-emitting element" may be used interchangeably. The light emitting device can have various forms and various elements. , display element, display device, light-emitting element or light-emitting device is EL (electroluminescence) Elements (EL elements including organic and inorganic materials, organic EL elements, inorganic EL elements), LEDs (white LED, red LED, green LED, blue LED, etc.), transistor (lights up depending on the current) transistors), electron emission devices, liquid crystal devices, electronic ink, electrophoretic devices, gratings Bright light bulb (GLV), plasma display panel (PDP), digital microphone mirror device (DMD), piezoelectric ceramic display, carbon nanotube, etc. A display medium whose contrast, brightness, reflectance, transmittance, etc. change due to electromagnetic effects. The display device using the EL element may be an EL display, A display device using electron-emitting elements is a field emission display (FED). and SED flat panel displays (SED: Surface-conduction E As a display device using liquid crystal elements, such as a LC-emitter display LCDs (transmissive LCDs, semi-transmissive LCDs, reflective LCDs) LCDs, direct-view LCDs, projection LCDs), electronic ink and An example of a display device using electrophoretic elements is electronic paper.

[0023] A liquid crystal element is a device that controls the transmission or non-transmission of light by the optical modulation action of liquid crystals. It is composed of a pair of electrodes and liquid crystal. Controlled by the electric field applied to the crystal (including the horizontal electric field, the vertical electric field, or the diagonal electric field) The liquid crystal elements include nematic liquid crystal, cholesteric liquid crystal, smectic Liquid crystal, discotic liquid crystal, thermotropic liquid crystal, lyotropic liquid crystal, low molecular weight liquid crystal, Polymer liquid crystal, polymer dispersed liquid crystal (PDLC), ferroelectric liquid crystal, antiferroelectric liquid crystal, main chain liquid crystal, Examples include side-chain polymer liquid crystals, plasma-addressed liquid crystals (PALCs), and banana-shaped liquid crystals. The liquid crystal driving method is Twisted Nematic (TN). mode, STN (Super Twisted Nematic) mode, IPS (In- Plane-Switching mode, FFS (Fringe Field Switching) mode tching) mode, MVA (Multi-domain Vertical Alignment gnment) mode, PVA(Patterned Vertical Alignm) ent) mode, ASV (Advanced Super View) mode, ASM ( Axially Symmetrically aligned Micro-cell) mode , OCB (Optically Compensated Birefringence) ) mode, ECB (Electrically Controlled Birefringence ngence) mode, FLC (Ferroelectric Liquid Crystal tal) mode, AFLC(AntiFerroelectric Liquid Cr systal mode, PDLC (Polymer Dispersed Liquid Crystal Crystal mode, guest host mode, Blue Phase mode However, the present invention is not limited to this, and the liquid crystal element and its driving method can be used. A variety of different types can be used.

[0024] Note that various types of transistors can be used as the transistor. There is no limitation on the type of transistor used. For example, amorphous silicon, polycrystalline silicon, microcrystalline silicon, Crystalline (also called microcrystalline, nanocrystalline, or semi-amorphous) silicon, etc. It is possible to use thin film transistors (TFTs) having non-single crystal semiconductor films, such as Yes, it is possible.

[0025] When producing polycrystalline silicon, a catalyst (such as nickel) is used to This further improves the crystallinity, making it possible to manufacture a transistor with good electrical characteristics. When producing microcrystalline silicon, the crystallinity can be improved by using a catalyst (such as nickel). This further improves the electrical characteristics of the transistors, making it possible to manufacture transistors with good electrical characteristics. It is possible to produce polycrystalline silicon and microcrystalline silicon without using a catalyst (such as nickel). It is Noh.

[0026] In addition, improving the crystallinity of silicon to polycrystalline or microcrystalline can improve the overall panel performance. It is desirable to do this on the whole body, but it is not limited to this. The crystallinity of the silicon may be improved.

[0027] Alternatively, a transistor can be formed using a semiconductor substrate, an SOI substrate, or the like.

[0028] Or ZnO, a-InGaZnO, SiGe, GaAs, IZO, ITO, SnO , TiO, AlZnSnO (AZTO), or other compound semiconductors or oxide semiconductors Transistors and thin film transistors made by thinning these compound semiconductors or oxide semiconductors It is possible to use a compound semiconductor or an oxide semiconductor. It can be used not only for the channel part of a transistor but also for other purposes. For example, these compound semiconductors or oxide semiconductors can be used as resistor elements, pixel electrodes, transparent Furthermore, they can be formed as a film or as an electrode having a transistor. can be formed, thereby reducing costs.

[0029] Alternatively, a transistor formed by inkjet or printing can be used. come.

[0030] Alternatively, transistors having organic semiconductors or carbon nanotubes can be used. This allows transistors to be formed on a flexible substrate. A semiconductor device using such a substrate can be made resistant to shocks.

[0031] Furthermore, transistors of various structures can be used. For example, MOS transistors The transistors used may be junction transistors, bipolar transistors, etc. This can be done.

[0032] In addition, MOS transistors, bipolar transistors, etc. can be mixed on one substrate. It may be formed.

[0033] In addition, various other transistors can be used.

[0034] Note that a transistor can be formed using various substrates. The substrate is not limited to a specific one. For example, the substrate may be a single crystal substrate (e.g., silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate, metal substrate, stainless steel Substrate with stainless steel foil, tungsten substrate, tungsten A substrate having a glass foil, a flexible substrate, etc. can be used. Examples include barium borosilicate glass and aluminoborosilicate glass. Examples of substrates include polyethylene terephthalate (PET) and polyethylene naphthalate. Plastics such as polyethersulfone (PEN) and polyethersulfone (PES) or acrylic Other examples include laminated films (polypropylene, etc.) polyethylene, polyester, vinyl, polyvinyl fluoride, polyvinyl chloride, etc.), including fibrous materials Paper, base film (polyester, polyamide, polyimide, inorganic vapor deposition film, paper Or, a transistor is formed on one substrate, and then transferred to another substrate. The transistors may be transposed and placed on a different substrate. The substrates that can be placed include single crystal substrates, SOI substrates, glass substrates, quartz substrates, and plastic substrates. Substrate, paper substrate, cellophane substrate, stone substrate, wood substrate, fabric substrate (natural fiber (silk, cotton, linen) , synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate, (including cupra, rayon, recycled polyester, etc.), leather substrate, rubber substrate, stainless steel A stainless steel substrate, a substrate with stainless steel foil, etc. can be used. Alternatively, the skin (epidermis, dermis) or subcutaneous tissue of an animal such as a human may be used as the substrate. Alternatively, a substrate may be used to form the transistors, and the substrate may be polished to make it thinner. The substrates that can be polished include single crystal substrates, SOI substrates, glass substrates, quartz substrates, and plastic substrates. The substrates used are stainless steel substrates, stainless steel foil substrates, etc. By using these substrates, it is possible to form transistors with good characteristics and to Formation of low-power transistors, manufacturing of durable devices, imparting heat resistance, weight reduction, This allows for a thinner design.

[0035] The structure of the transistor can take various forms and is not limited to a specific structure. For example, a multi-gate structure having two or more gate electrodes can be applied.

[0036] As another example, a structure in which gate electrodes are arranged above and below the channel can be applied. In addition, by arranging gate electrodes above and below the channel, multiple transistors can be formed. The configuration is like that of transistors connected in parallel.

[0037] A structure in which a gate electrode is disposed above a channel region, and a structure in which a gate electrode is disposed below a channel region The structure in which the channel region is divided into multiple regions is also available. a structure in which the channel regions are connected in parallel, or a structure in which the channel regions are connected in series Furthermore, the channel region (or a part thereof) can be provided with a source electrode or a drain electrode. A structure in which the two are overlapped can also be applied.

[0038] Note that various types of transistors can be used and can be formed using various substrates. Therefore, all the circuits required to realize a given function can be simultaneously For example, it is possible to form the circuit necessary to realize a predetermined function on a single substrate. All of the circuits are made on various substrates such as glass, plastic, single crystal, or SOI. Alternatively, it may be formed using a substrate that is necessary to realize a predetermined function. A part of the essential circuit is formed on a certain substrate, and a part of the circuit necessary to realize a predetermined function is formed on the substrate. It is also possible for a part of the semiconductor device to be formed on a separate substrate. All of the circuits required for the above may not be formed using the same substrate. Part of the circuitry required to realize this function is formed by transistors on a glass substrate. Another part of the circuitry required to realize a predetermined function is formed on the single crystal substrate, An IC chip consisting of transistors formed on a single crystal substrate is called COG (Chip On Glass). On Glass) and place the IC chip on the glass substrate. Alternatively, the IC chip can be inserted into a TAB (Tape Automate) It is also possible to connect it to the glass substrate using a printed circuit board or a bonding method.

[0039] A transistor is defined as a transistor having at least three terminals including a gate, a drain, and a source. The element has a channel region between a drain region and a source region. A current can flow through the drain region, the channel region, and the source region. The source and drain depend on the transistor structure and operating conditions, so it is difficult to know which is the source and which is the drain. Therefore, it is difficult to determine whether the source or drain is the source or drain. The region that functions as a source or drain is sometimes not called a source or drain. In some cases, they are referred to as the first terminal and the second terminal. They may be referred to as the first electrode and the second electrode. Alternatively, they may be referred to as the first region and the second region. There is a match.

[0040] The transistor has at least three terminals including a base, an emitter, and a collector. In this case, the emitter and the collector may be connected to the first terminal and the second terminal. It may be written as 2 terminals, etc.

[0041] Note that it is not explicitly stated that B is formed on A, or that B is formed on A. In the case of the above, it is not limited to B being formed on A in direct contact with it. This also includes cases where A and B are not in agreement, i.e., where another object is present between A and B. Here, A and B are objects (e.g., devices, elements, circuits, wiring, electrodes, terminals, conductive films, layers, etc.). , etc.).

[0042] Therefore, for example, it is not possible to explicitly state that layer B is formed on top of layer A (or on top of layer A). When described, it means that layer B is formed directly on layer A, and layer A is formed on layer B. Another layer (such as layer C or layer D) is formed directly on top of it, and layer B is formed directly on top of it. It should be noted that other layers (such as layers C and D) may be formed as follows: It may be a single layer or multiple layers.

[0043] Furthermore, the same applies to cases where it is explicitly stated that B is formed above A. It is not limited to B being directly on A, and there is another object between A and B. For example, if layer B is formed above layer A, In this case, there are two cases: when layer B is formed directly on top of layer A, and when layer B is formed directly on top of layer A. Another layer (such as layer C or layer D) is formed on top of it, and layer B is formed directly on top of it. It should be noted that other layers (such as layers C and D) may be used as single layers. It may be a multi-layer structure.

[0044] In addition, B is formed on A, B is formed on A, or B is formed above A. When explicitly stating that "B" is formed, this also includes the case where B is formed diagonally above. .

[0045] The same applies to the case where B is below A, or B is below A.

[0046] In addition, it is preferable that anything explicitly stated as singular be in the singular. However, it is not limited to this, and plurals are also possible. It is preferable that the items described in the table be plural. However, this is not limited to this. It is also possible for the term to be singular.

[0047] In the drawings, the size, thickness of layers, or areas may be exaggerated for clarity. Therefore, it is not necessarily limited to that scale.

[0048] The diagrams are merely diagrams showing ideal examples, and are not limited to the shapes or values ​​shown in the diagrams. For example, variations in shape due to manufacturing technology, variations in shape due to errors, and noise Variations in signals, voltages, or currents due to timing differences, or variations in signals, voltages, Alternatively, it is possible to include variations in current.

[0049] Note that technical terms may be used to describe specific embodiments or examples. However, one aspect of the invention should not be interpreted as being limited by technical terms.

[0050] In addition, undefined terms (including scientific and technical terms such as technical terms or academic terms) are generally It can be used as a meaning equivalent to the general meaning understood by a person of ordinary skill in the art. The terms defined herein shall be construed in a manner consistent with the background of the relevant art. is preferred.

[0051] It should be noted that the terms first, second, third, etc., refer to various elements, members, regions, layers, and sections as distinct from one another. Therefore, the words "first," "second," "third," etc. are used to distinguish between elements, parts, etc. It is not intended to limit the number of materials, regions, layers, areas, etc. It is possible to replace "second" or "third" etc.

[0052] In addition, "up," "upward," "down," "downward," "sideways," "right," "left," Spatial arrangement such as "diagonally," "in the back," "in front," "inside," "outside," or "inside" The location phrases should be used to easily illustrate the relationship of one element or feature to another. However, it is not limited to this and is often used to indicate the spatial arrangement of these. The phrase "above A" can include other directions in addition to the direction shown in the drawing. For example, When explicitly indicated as B, B is not limited to being above A. can be flipped or rotated 180 degrees, so it can include B being below A. In this way, the word "upon" can be used to refer to the direction of "up" as well as the direction of "down." The devices shown may include, but are not limited to, various orientations. Since it is possible to rotate the word "on" in addition to the directions "on" and "under" "Sideways", "Right", "Left", "Diagonally", "Back", "Front", "Inside", "Outside" It is possible to include other directions such as "into" or "into"; It is possible to interpret this as: [Effects of the Invention]

[0053] One embodiment of the present invention can reduce the influence of variations in threshold voltage of a transistor. Another embodiment of the present invention is to reduce the influence of variations in mobility of transistors. Alternatively, one embodiment of the present invention can reduce the influence of variations in current characteristics of transistors. Alternatively, one embodiment of the present invention can secure a long input period of a video signal. Alternatively, one embodiment of the present invention is a method for reducing the influence of variations in threshold voltage. Alternatively, one embodiment of the present invention can provide a method for reducing the variation in mobility. A long correction period can be ensured to reduce the influence. In this case, the influence of the distortion of the waveform of the video signal can be reduced. In this case, not only line sequential driving but also point sequential driving can be used. In this embodiment, the pixel and the driver circuit can be formed over the same substrate. In addition, one embodiment of the present invention can reduce costs. Alternatively, one embodiment of the present invention can reduce poor contact at a connection portion of a wiring. come. [Brief explanation of the drawings]

[0054] [Figure 1] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 2] 1A to 1C illustrate a circuit or a driving method described in an embodiment. [Figure 3] 1A to 1C are diagrams illustrating operations described in an embodiment; [Figure 4] 1A to 1C illustrate a circuit or a driving method described in an embodiment. [Figure 5] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 6] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 7] 1A to 1C illustrate a circuit or a driving method described in an embodiment. [Figure 8] 1A to 1C illustrate a circuit or a driving method described in an embodiment. [Figure 9] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 10] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 11] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 12] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 13] 1A to 1C illustrate a circuit or a driving method described in an embodiment. [Figure 14] 1A to 1C illustrate a circuit or a driving method described in an embodiment. [Figure 15]1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 16] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 17] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 18] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 19] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 20] 1A to 1C are cross-sectional views illustrating a driving method described in an embodiment. [Figure 21] 1A to 1C are cross-sectional views illustrating block diagrams shown in embodiments. [Figure 22] 1A to 1C are cross-sectional views illustrating block diagrams shown in embodiments. [Figure 23] 1A to 1C are cross-sectional views illustrating a transistor described in an embodiment. [Figure 24] 1A to 1C are cross-sectional views illustrating a transistor described in an embodiment. [Figure 25] 1A to 1C illustrate a circuit or a driving method described in an embodiment; [Figure 26] 1A to 1C illustrate electronic devices described in embodiments. [Figure 27] 1A to 1C illustrate electronic devices described in embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0055] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention may be embodied in many different ways without departing from the spirit and scope thereof. It will be readily understood by those skilled in the art that various modifications can be made to the modes and details of the present invention. It should not be construed as being limited to the description of the embodiment. In the drawings, the same reference numerals are used to indicate the same parts or the same components. A detailed description of the parts having various functions will be omitted.

[0056] Note that the content (or even a part of the content) described in one embodiment may be used in conjunction with that embodiment. Other content (or even part of content) described in the above, and / or one or more other implementations The content (or part of the content) described in the form of You can do things like:

[0057] The contents described in the embodiments are explained in detail in each embodiment using various drawings. This refers to the content that is stated or the content that is stated using the text in the specification.

[0058] In addition, a drawing (or a part thereof) described in one embodiment may be different from another part of the drawing, Another figure (or a part thereof) described in the embodiment, and / or one or more By combining with the figure (or a part thereof) described in another embodiment of the present invention, , and many more diagrams can be constructed.

[0059] In addition, in a drawing or a sentence described in a certain embodiment, a part thereof may be extracted. Therefore, the drawings and drawings that illustrate certain parts of the invention may be omitted. If a part of a drawing or text is included in the invention, the part of the drawing or text may also be included in the invention. It is disclosed as an embodiment and may constitute an embodiment of the invention. Therefore, for example, active elements (transistors, diodes, etc.), wiring, passive elements (capacitive elements, resistive elements, etc.), conductive layers, insulating layers, semiconductor layers, organic materials, inorganic materials, components, Substrate, module, device, solid, liquid, gas, method of operation, method of manufacture, etc. The drawings (cross-section, plan view, circuit diagram, block diagram, flow chart, process chart, perspective view) , elevation view, layout diagram, timing chart, structural diagram, schematic diagram, graph, table, optical path diagram, vector diagram, state diagram, waveform diagram, photograph, chemical formula, etc.) or in a text, a part thereof is extracted and is assumed to be capable of constituting one aspect of the invention. As an example, from a circuit diagram composed of N (N is an integer) circuit elements (transistors, capacitor elements, etc.), M (M is an integer and M < N) circuit elements (transistors, capacitor elements, etc.) are extracted to constitute one aspect of the invention. Another example is that from a cross-sectional view composed of N (N is an integer) layers, M (M is an integer and M < N) layers are extracted to constitute one aspect of the invention. Another example is that from a flowchart composed of N (N is an integer) elements, M (M is an integer and M < N) elements are extracted to constitute one aspect of the invention. is possible. Another example is that from a flowchart composed of N (N is an integer) elements, M (M is an integer and M < N) elements are extracted to constitute one aspect of the invention. is possible. is possible.

[0060] (Embodiment 1) FIG. 1 shows an example of a driving method, driving timing, and circuit configuration at that time when correcting variations in current characteristics such as the mobility of a transistor. Note that in this embodiment, an example of an n-channel type transistor in terms of conductivity type will be described.

[0061] FIG. 1(A) shows a circuit configuration during a period in which variations in current characteristics such as the mobility of transistor 101 are corrected. The circuit configuration shown in FIG. 1(A) is a circuit configuration for discharging the charge held in the gate of the transistor in order to correct variations in current characteristics such as the mobility of transistor 101. Actually, the connection relationship of the circuit configuration is realized by controlling on or off of a plurality of switches provided between wirings. Note that FIG. ​ In the figure, the solid lines represent the conductive state between elements, and the dotted lines represent the non-conductive state between elements. do.

[0062] In FIG. 1A, one of the source and drain of the transistor 101 (hereinafter referred to as the first The first terminal (also referred to as a first electrode) of the capacitor 102 and the The source or drain of transistor 101 is in a conductive state. The other terminal (hereinafter referred to as the second terminal) is connected to the second terminal (or the second electrode) of the capacitor 102. The first terminal of the capacitor 102 is electrically connected to the gate of the transistor 101. The first electrode (or first electrode) of the transistor 101 is connected to the gate of the transistor 101 and the first terminals and is in a state of continuity.

[0063] The first terminal (or first electrode) of the display element 105 is connected to the second terminal of the transistor 101. The second terminal of the transistor 101 is in a non-conductive state with the second terminal of the capacitor 102. and a terminal, wiring, or electrode other than the second terminal of the capacitor 102 and the first terminal of the display element 105. It is desirable that the first terminal (or first electrode) of the display element 105 is in a non-conductive state. The second terminal (or second electrode) is preferably in a state of electrical continuity with the wiring 106.

[0064] Note that when the first terminal of the display element 105 and the second terminal of the transistor 101 are not in a conductive state, Instead, the potential of the wiring 106 is high, and the display element 105 is reverse biased. Since the display element 105 is in the asymmetric state, almost no current flows through the display element 105. Good too.

[0065] The wiring 104 is not electrically connected to the first terminal of the transistor 101. 04 is in a non-conductive state with the first terminal (or the first electrode) of the capacitor 102. As shown in FIG. 1A, the wiring 104 is connected to the first terminal of the transistor 101 and the capacitor The terminals, wirings, or electrodes other than the first terminal (or first electrode) of 102 are in a non-conductive state. It is desirable that it be in.

[0066] Note that a video signal or a Therefore, the wiring 104 is connected to the source signal line, the image These may be called signal lines or video signal lines.

[0067] Before the connection configuration shown in FIG. 1A is established, the mobility of the transistor 101, etc. Before correcting the variation in the current characteristics of the transistor 101, the capacitance element 102 is It is desirable that the voltage corresponding to the threshold voltage is maintained. It is desirable that the signal be input to the capacitor 102 via the wiring 104. The capacitor 102 receives a voltage corresponding to the threshold voltage of the transistor 101 and a video signal. It is desirable that the sum of the voltages is maintained. Therefore, in the state before FIG. 1(A), That is, before correcting the variations in the current characteristics such as the mobility of the transistor 101, The wiring 104 is connected to the drain, source, and gate of the transistor 101 and the capacitor 102. The first terminal, the second terminal, etc. are in a conductive state with at least one of the terminals, and the video signal is already It is desirable that an input operation is being performed.

[0068] Note that the capacitor 102 generates a voltage and a It is desirable that the voltage of the sum of the video signal voltages is held in the capacitor element 102. The voltage corresponding to the threshold voltage of the resistor 101 is not held, and only the video signal voltage is held. It is also possible that

[0069] When the voltage is held by the capacitor 102, the voltage may be increased by switching noise or the like. However, this is within a range that does not affect actual operation. Therefore, for example, the threshold voltage of the transistor 101 is When the sum of the voltage according to the voltage and the video signal voltage is input to the capacitance element 102, The voltage held in the capacitance element 102 at this time does not completely match the input voltage. However, there may be slight differences due to noise and other factors. It's okay if the timing is a little off as long as it doesn't cause any disturbance.

[0070] Next, in FIG. 1B, a current is supplied to the display element 105 through the transistor 101. The circuit configuration shown in FIG. 1(B) is a circuit configuration in which a transistor This is a circuit configuration for supplying current from the capacitor 101 to the display element 105, and in reality, By controlling the on / off of the multiple switches provided, the connection relationship of the circuit configuration is It will be realized.

[0071] The first terminal of the transistor 101 is electrically connected to the wiring 103. The second terminal of the capacitor 102 is electrically connected to the first terminal of the display element 105 and the second terminal of the capacitor 102. The first terminal of the transistor 101 is in a non-conductive state with the gate of the transistor 101. The first terminal of the capacitor 102 is electrically connected to the gate of the transistor 101. The second terminal of the capacitor 102 is connected to the second terminal of the transistor 101 and the second terminal of the display element 10. The second terminal of the display element 105 is electrically connected to the wiring 106. It is in this state.

[0072] The wiring 104 is not electrically connected to the first terminal of the transistor 101. The wiring 104 is not electrically connected to the first terminal of the capacitor 102. As shown in (B), the first terminal of the transistor 101 and the first terminal of the capacitor element 102 are connected to each other. It is desirable that the external terminals, wiring or electrodes are in a non-conductive state.

[0073] That is, the period during which the variations in current characteristics such as the mobility of the transistor 101 are corrected (see FIG. 1(A)) supplies current to the display element 105 via the transistor 101. When the transition to the period (FIG. 1B) occurs, at least the first terminal of the transistor 101 and the gate of the transistor 101, and the second terminal of the transistor 101. The conduction state with the first terminal of the element 105 changes, but the invention is not limited to this. The conduction state of the portion can be changed. And, the conduction state can be controlled as described above. It is desirable to arrange elements such as switches, transistors, or diodes in this manner. Then, the conductive state is controlled using the element, and the connection state shown in Figure 1(A) and Figure 1(B) is realized. Therefore, it is possible to realize a circuit configuration such as shown in Fig. 1(A) and Fig. 1(B). If the connection state can be realized, elements such as switches, transistors, or diodes can be automatically The number of the electrodes and the connecting structure are not limited.

[0074] As an example, as shown in FIG. 2A, the first terminal of the switch 201 is connected to the transistor 1 The gate of the switch 201 is electrically connected to the first terminal of the capacitor 102. The terminal of the switch 202 is electrically connected to the first terminal of the transistor 101. The first terminal of the transistor 101 is electrically connected to the second terminal of the capacitor 102. and electrically connects the second terminal of the switch 202 to the first terminal of the display element 105. Then, the first terminal of the switch 203 is electrically connected to the wiring 103, and the switch 2 The second terminal of the transistor 101 is connected to the second terminal of the switch 201 and the first terminal of the transistor 101. Then, the first terminal of the switch 204 is electrically connected to the first terminal of the switch 201. , the gate of the transistor 101 and the first terminal of the capacitor 102 are electrically connected to each other. The second terminal of the switch 204 is electrically connected to the wiring 104. In this way, the four switches By placing the switches, the circuit configuration can be realized as shown in Figure 1(A) and Figure 1(B). This can be achieved.

[0075] Examples other than that shown in Figure 2(A) are shown in Figures 2(B), 2(C), and 2(D). In Figure 2(B), 2A, a switch 205 is newly provided to control the connection with the wiring 206. The configuration shown in FIG. 2C controls the potential of the second terminal of the transistor 101. In FIG. 2A, a switch 207 is newly provided to control the connection with the wiring 208. The structure shown in FIG. 2D is for controlling the gate potential of the transistor 101. 2B, a switch 207 is newly provided to control the connection with the wiring 208. The potential of the gate of the transistor 101 and the potential of the second terminal of the transistor 101 are controlled. For example, the potential of the wiring 206 or the wiring 208 is changed. By doing so, it is possible to realize the same operation as in FIG. 1(A) or FIG. 1(B). If further switches, transistors, etc. are required, they are placed as appropriate.

[0076] Although it is stated that A is in a conductive state with B, in this case, there are various It is possible for various elements to be connected. For example, resistors, capacitors, transistors, etc. , diodes, etc. are connected in series or parallel between A and B. Similarly, it is stated that A is in a non-conductive state with B, but in that case, A and B It is possible that various elements are connected between A and B. It is possible for various elements to be connected in other parts. For example, resistors, capacitors, transistors, diodes, and other elements are connected in series. Alternatively, they may be connected in parallel.

[0077] Next, we will explain the operation method. Here, we will use the circuit in Figure 2(A), but A similar method of operation can be used for other circuits.

[0078] First, as shown in FIG. 6A, initialization is performed. This is performed by setting the gate of the transistor 101, Alternatively, it is an operation of setting the drain (or source) potential to a predetermined potential. As a result, the transistor 101 can be turned on. A predetermined voltage is supplied to the capacitor 102. Therefore, a charge is held in the capacitor 102. The switches 201, 202, and 203 are in a conducting state. As for switch 204, it is in a non-conducting state and is therefore off. However, it is not limited to this. However, it is also preferable that no current flows through the display element 105. Therefore, it is desirable to be in a position where this can be realized. At least one of the switches 201, 202, and 203 Preferably, one of the resistors is non-conducting and off.

[0079] In Figures 6(A) to 6(E), the dotted arrows indicate the movement of the charges. However, the present invention is not limited to this, and the potential If it's a relationship, there's no problem.

[0080] Next, as shown in FIG. 6B, the threshold voltage of the transistor 101 is obtained. Switch 201 and switch 203 are in a conductive state and are turned on. The switch 204 is preferably in a non-conductive state and is turned off. Since the charge stored in the capacitor 102 during the period shown in FIG. 6(A) is released, Therefore, the potential of the gate of the transistor 101 is The threshold voltage (positive value) of the transistor 101 is increased from the potential due to the charge stored in the transistor 101. In other words, the absolute value of the threshold voltage of the transistor 101 approaches At this time, the potential between the gate and source of the transistor 101 approaches a potential that is higher by a factor of 1. The voltage approaches the threshold voltage of the transistor 101. The threshold voltage can be obtained between the electrodes at both ends of the element 102.

[0081] During this period, when the charge of the capacitor element 102 is discharged, the period may differ. However, this is not a big problem because after a certain amount of time has passed, the battery will be almost completely discharged. Therefore, even if the length of the period differs, the effect on the operation is small. This operation can be driven using point sequence rather than line sequence. The drive circuit can be realized with a simple configuration. Therefore, the circuit shown in Figure 2(A) can be When the pixel is a single pixel, the pixel section is arranged in a matrix and the signal is supplied to the pixel section. The driving circuit section that supplies the signal to the driving circuit section is configured using the same type of transistors. Alternatively, they can be formed on the same substrate. However, this is not limited to this, and they can be formed by using line sequential driving. Alternatively, the pixel portion and the driver circuit portion may be formed on different substrates.

[0082] Next, as shown in FIG. 6(C), a video signal is input. Switch 4 is in a conducting state and is turned on. Switch 201 and switch 203 are in a non-conducting state. The video signal is supplied from the wiring 104. At this time, the charge stored in the capacitor 102 during the period of FIG. Therefore, the charge on the gate of the transistor 101 is further accumulated. The potential is determined by the threshold voltage (positive) of the transistor 101 from the video signal supplied from the wiring 104. That is, the potential of the video signal supplied from the wiring 104 approaches the potential obtained by adding the values ​​of the video signals (the value of the video signal) The potential approaches a potential higher by the absolute value of the threshold voltage of the transistor 101 than the potential at the threshold voltage of the transistor 101. By the operations of FIG. 6(B) and FIG. 6(C), the video signal is input and the threshold voltage is acquired. It is possible.

[0083] 25(A) and 25(B), a capacitance element 250 is electrically connected in parallel with the display element 105. 25(A) and 25(B), a capacitor element 1 may be arranged. The first terminal of the capacitor 2501 is connected to the first terminal of the display element 105, and the second terminal of the capacitor 2501 is connected to the first terminal of the display element 105. The transistor 101 is connected to the second terminal of the display element 105. During the period when the variations in current characteristics such as the mobility of 25(B) is a diagram showing the conductive and non-conductive states in the same way as FIG. 1(A). During the period when current is supplied to the display element 105 via the transistor 101, This figure shows the conductive and non-conductive states between the elements, similar to FIG. 1(B). By configuring the circuits in (A) and (B), the voltage obtained by adding the threshold voltage and the video signal voltage is It can be made close to.

[0084] Next, as shown in FIG. 6(D), the variation in current characteristics such as the mobility of the transistor 101 is This corresponds to the period shown in FIG. 1(A). Switches 202, 203, and 204 are in the on state and are turned on. It is desirable that the transistor is in a non-conducting state and turned off. As a result, the charge stored in the capacitor 102 is discharged through the transistor 101 . In this way, a small discharge through transistor 101 This can reduce the influence of variations in the current of the starter 101.

[0085] Next, as shown in FIG. 6(E), a current is applied to the display element 105 via the transistor 101. This corresponds to the period shown in FIG. 1B. Switch 203 is in a conductive state and is turned on. It is desirable that the transistor 101 is in a non-conducting state and is off. The voltage between the gate and source is the sum of the voltage according to the threshold voltage and the video signal voltage. The voltage obtained by subtracting a voltage according to the current characteristics of the transistor 101 from the voltage obtained by the Therefore, the influence of variations in the current characteristics of the transistor 101 can be reduced, and the display element The terminal 105 can be supplied with a current of an appropriate magnitude.

[0086] As shown in FIGS. 6A to 6E, the current characteristics of the transistor 101, such as the mobility, vary. During the period when the charge is corrected (FIG. 1A), the voltage such as the mobility of the transistor 101 is Since the variation in current characteristics is reduced, the period during which current is supplied to the display element 105 (FIG. 1 In (B), the variation in the current supplied to the display element 105 is also reduced. This reduces variations in the display state of the display element 105, making it possible to perform high-quality display. come.

[0087] During the period when a current is supplied to the display element 105 (FIG. 1B), the transistor 10 The period when the variation in the current characteristics such as the mobility of 1 is corrected (Fig. 1(A)) appears immediately after the correction period. This is because, during the period when a current is supplied to the display element 105 (FIG. 1(B)), )) the gate potential of the transistor 101 (the potential held in the capacitor 102) During the period when current is supplied to the display element 105 (FIG. 1(B)), However, the current characteristics of the transistor 101, such as the mobility, The current is supplied to the display element 105 immediately after the period in which the fluctuation is corrected (FIG. 1(A)). The present invention is not limited to the appearance of the period (FIG. 1B) in which the mobility of the transistor 101 is increased. During the period when the variation in the current characteristics is being corrected (FIG. 1A), The amount of charge changes, and the amount of charge of the capacitance element 102 determined at the end of the period is When there is no significant change during the period when current is supplied to O5 (Fig. 1(B)), The period during which the variation in current characteristics such as the mobility of the transistor 101 is corrected (see FIG. 1) Between the period in which a current is supplied to the display element 105 (FIG. 1(A)) and the period in which a current is supplied to the display element 105 (FIG. 1(B)), another A period during which the process is performed may be set.

[0088] Therefore, during the period in which the variations in current characteristics such as the mobility of the transistor 101 are corrected, When the charge held in the capacitor element 102 is discharged, the current supplied to the display element 105 is The charge stored in the capacitor 102 at the time when the period of time during which the current is applied is approximately the same as that at the time when the current is applied. However, due to the influence of noise, etc., the amount of charge on both sides may differ slightly. Specifically, the difference in the amount of charge between the two should be within 10%, and more preferably If the difference in charge amount is within 3%, the display element will reflect that difference. This is more desirable because the difference is not visible to the human eye.

[0089] Therefore, the period during which the variations in current characteristics such as the mobility of the transistor 101 are corrected (Fig. FIG. 3(A) shows how the voltage-current characteristics change in the case of the voltage-current characteristic (1(A)). The charge stored in the capacitor 102 is transferred to the transistor 101 through the current characteristics such as the mobility. During the period when the variation is being corrected (FIG. 1(A)), the source and drain of the transistor 101 As a result, the charge held in the capacitance element 102 is discharged. The amount of current decreases, and the voltage held in the capacitance element 102 also decreases. The absolute value of the voltage between the gate and source of the transistor 101 also decreases. The stored charge is discharged through the transistor 101, so the amount of discharged charge is depends on the current characteristics of the transistor 101. That is, the mobility of the transistor 101 If the voltage V is higher, more charge is discharged. If the ratio (W / L) of the channel length L is large, more charges are discharged. If the absolute value of the voltage between the gate and source of the transistor 101 is large (i.e., the capacitance element 1 The greater the absolute value of the voltage held at O2, the more charge is discharged. If the parasitic resistance in the source and drain regions of the transistor 101 is small, more Alternatively, if the resistance in the LDD region of the transistor 101 is small, Alternatively, the capacitor electrically connected to the transistor 101 is discharged. If the contact resistance in the contact hole is small, more charge is discharged.

[0090] Therefore, before discharging, that is, to compensate for variations in current characteristics such as the mobility of the transistor 101, The voltage-current characteristic graph for the period before the correcting period (Fig. 1(A)) shows that the During the period when the variations in the current characteristics such as the mobility of the transistor 101 are corrected (Fig. 1(A)), As a result of a part of the charge stored in the capacitor 102 being discharged, a curve with a small slope is formed. For example, the difference between the voltage-current characteristic graphs before and after discharge is The larger the mobility of the transistor 101, the larger the When the mobility of ions is high (i.e., when the slope of the graph is steep), the change in the slope after discharge When the amount of charge is large and the mobility of the transistor 101 is low (i.e., the slope of the graph is small), As a result, after discharge, the amount of change in the slope becomes smaller. The difference in the voltage-current characteristics graph becomes smaller when the mobility of the sintered body is high or low. In this way, the influence of variations in mobility can be reduced. If the absolute value of the voltage between the gate and the source is large (i.e., the voltage held by the capacitance element 102 The larger the absolute value of , the more charge is discharged and the If the absolute value of the voltage between the capacitors is small (i.e., the absolute value of the voltage held by the capacitor 102 value), the amount of charge discharged is smaller, so the mobility variation is more appropriately It is possible to reduce

[0091] The graph in Figure 3(A) shows the results after the influence of the threshold voltage variation has already been reduced. Therefore, as shown in FIG. 3B, the mobility of the transistor 101 Before the compensation period (Fig. 1(A)), the influence of the threshold voltage variation is The voltage-current characteristic graph is is translated by the threshold voltage. The voltage supplied is the sum of the video signal voltage and the threshold voltage. The influence of the variation is reduced. After reducing the variation of the threshold voltage, As shown in the figure, by reducing the mobility variation, the current of the transistor 101 The variation in characteristics can be significantly reduced.

[0092] The current characteristics of the transistor 101 that can correct the variations are Not only mobility, but also threshold voltage, parasitic resistance in the source or drain region, and the resistor, the contact in the contact hole electrically connected to the transistor 101 These current characteristics are also determined by the fact that the charge is discharged through the transistor 101. Therefore, the variation can be reduced in the same way as in the case of mobility.

[0093] Therefore, before discharging, the variation in the current characteristics such as the mobility of the transistor 101 is corrected. The charge amount of the capacitor 102 in the period before the transition period (FIG. 1A) is At the end of the period (Fig. 1(A)) during which the variations in the current characteristics such as the mobility of the transistor 101 are corrected, This is because the amount of charge in the capacitor 102 at the time of the transfer of the transistor 101 is larger than the amount of charge in the capacitor 102 at the time of the transfer of the transistor 101. During the period when the variations in current characteristics such as mobility are corrected (FIG. 1(A)), the capacitance element 102 Since the charge stored in the capacitor 102 is discharged, the charge stored in the capacitor 102 decreases. is.

[0094] It should be noted that once the charge held in the capacitance element 102 is partially discharged, the discharge immediately stops. If the battery is completely discharged, that is, if the current stops flowing, If the discharge is complete, most of the video signal information will be lost. It is desirable to stop the discharge before the current flows through transistor 101. It is desirable to stop the discharge while the current is flowing.

[0095] Therefore, one gate selection period (or one horizontal period, or one frame period) is divided by the number of pixel rows. The calculated value is used to correct for variations in the current characteristics such as the mobility of the transistor 101. When comparing the length of one gate selection period (or one horizontal period, 1 It is desirable that the pixel period (e.g., the frame period divided by the number of pixel rows) is longer because This is because discharging for longer than one gate selection period may result in over-discharging. However, it is not limited to this.

[0096] Alternatively, the period during which a video signal is input to the pixel and the current such as the mobility of the transistor 101 may be Comparing the period during which the characteristic variations are corrected (Fig. 1(A)), the video signal is It is desirable that the period during which the image signal is input is longer than the period during which the image signal is input to the pixel. If the discharge is continued for a period longer than the specified time, there is a possibility that the battery will be over-discharged. , but is not limited to this.

[0097] Alternatively, the period during which the threshold voltage of the transistor is acquired and the movement of the transistor 101 Comparing the length of the period during which the variation in current characteristics such as the current flow rate is corrected (Fig. 1(A)), It is desirable that the period during which the threshold voltage of the transistor is acquired is longer because If the discharge is continued for a period longer than the period during which the transistor threshold voltage is acquired, the discharge will be too long. However, this is not limited to this.

[0098] Note that during the period when variations in current characteristics such as the mobility of the transistor 101 are corrected (see FIG. 1 In (A), the length of the period during which the charge held in the capacitance element 102 is discharged is, for example, For example, the amount of variation in the mobility of the transistor 101, the size of the capacitance element 102, It is desirable to determine this based on W / L of 101, etc.

[0099] For example, consider the case where there are multiple circuits shown in Figures 1 and 2. For example, a first pixel for displaying a second color and a second pixel for displaying a second color, Each pixel has a transistor corresponding to transistor 101, and the first pixel has a transistor The first pixel has transistor 101A and the second pixel has transistor 101B. The first pixel uses a capacitor element 102A as a capacitive element corresponding to the capacitor element 102, and the second pixel uses a capacitor element 102B as a capacitive element corresponding to the capacitor element 102. The element has a capacitance element 102B.

[0100] The W / L of the transistor 101A is greater than the W / L of the transistor 101B. In this case, the capacitance value of the capacitive element 102A is larger than the capacitance value of the capacitive element 102B. This is because the transistor 101A discharges more charge than the capacitance element. The voltage of the capacitor 102A also changes more significantly. It is desirable that the capacitance value of element 102A is large. When the channel width W of the transistor 101B is larger than the channel width W of the capacitor 102A, It is desirable that the capacitance value of the capacitor 102B is larger than the capacitance value of the capacitor 102B. The channel length L of the transistor 101A is smaller than the channel length L of the transistor 101B. In this case, the capacitance value of the capacitive element 102A is larger than the capacitance value of the capacitive element 102B. However, it is not limited to this.

[0101] In order to control the amount of discharge of the charge held in the capacitor 102, a capacitor For example, as shown in Figures 25(A) and 25(B), A capacitor element 2501 may be added electrically in parallel with the element 105. A capacitance element 2502 is electrically connected in parallel between the first terminal and the second terminal of the transistor 101. 25(C) and 25(D) show the first and second terminals of the transistor 101. 2. The circuit configuration shown in FIG. 2 is such that a capacitor 2502 is electrically connected in parallel between the 5(C) is a period during which variations in current characteristics such as the mobility of the transistor 101 are corrected. The conductive and non-conductive states between the wirings and elements are shown in the same manner as in FIG. 1(A). 25(D) shows a state in which a current is supplied to the display element 105 through the transistor 101. The conduction and non-conduction states between each wiring and each element during the period shown in Figure 1(B) are shown. 25(A) to 25(D). The magnitude of the quantity value may vary from pixel to pixel.

[0102] The circuit connection structure is not limited to that shown in FIG. 1(A) and FIG. 1(B). In A), the first terminal of the transistor 101 and the first terminal of the capacitor 102 are connected to the wiring 10 3 is in a non-conductive state, and the second terminal of the transistor 101 is in a non-conductive state with the first terminal of the display element 105. In addition, as an example, in FIG. 1(B), a constant potential is applied. The wiring 103 having the function of supplying current is in electrical continuity with the first terminal of the transistor 101. It is sufficient that the second terminal of the transistor 101 and the first terminal of the display element are in a conductive state. As a connection configuration of other circuits, for example, the first terminal of the transistor 101 is connected to the wiring 103. 1C and 1D show examples of the case where the transistor 10 is connected to the The first terminal of the transistor 101 compensates for variations in current characteristics such as mobility of the transistor 101. An example in which the signal is connected to the wiring 103 via the circuit element 107 during the period is shown in FIG. 1(E). 1F. The first terminal of the transistor 101 is connected to the The period during which the variations in current characteristics such as mobility are corrected and the period during which current is supplied to the display element 105 4 shows an example in which the circuit element 107 is connected to the wiring 103 during the period in which the 4A and 4B. Also, the current characteristics of the transistor 101, such as the mobility, vary. During the period when the voltage is being corrected, the wiring 108 having the function of supplying a constant potential is connected to the transistor. An example in which the second terminal of the first terminal 101 is connected to the second terminal of the first terminal 102 so as to be in a conductive state is shown in FIG. 4D. The second terminal of the transistor 101 is connected to the The period during which the variations in current characteristics such as mobility are corrected and the period during which current is supplied to the display element 105 4 shows an example in which the circuit element 109 is connected to the wiring 108 during the period in which the power supply is in a non-volatile memory. 4(E) and 4(F). The second terminal of the transistor 101 is connected to the During the period when the variations in current characteristics such as the mobility of O1 are being corrected, An example of the case where the transistor is connected to the wiring 106 is shown in FIG. 5(A) and FIG. 5(B). During the period when the variation in the current characteristics such as the mobility of the transistor 101 is corrected, A first terminal of the transistor 101 is connected to a wiring 103, and a second terminal of the transistor 101 is connected to a display element An example of the case where the wiring 106 is connected via the wiring 105 is shown in FIG. 5(C) and FIG. 5(D). .

[0103] In addition, in Figs. 1(C) to 1(F), as in Figs. 2(A) to 2(D), A switch can be placed.

[0104] The circuit elements 107 and 109 may include a capacitance element, a resistance element, a diode element, and the like. A device that can combine electrical elements such as resistors and switches to achieve a desired electrical connection state. It is possible to use a child.

[0105] The operations of FIG. 1(C) and FIG. 1(D) are specifically shown in FIGS. 6(A) to 6(E) and Similarly, it can be realized through operations such as initialization.

[0106] The operations of FIGS. 1(C) and 1(D) are shown in FIGS. 9(A) to 9(E). As for the specific operation, it is executed through the operations such as initialization as shown in FIG. 6(A) to FIG. 6(E). It can be realized.

[0107] The configurations shown in Figures 4(C) and 4(D) can be realized by the circuit configuration shown in Figure 2(B). This can be done.

[0108] 1(A) to 1(F), 2(A) to 2(D), and 4(A) to 4(F) ) and the like, the capacitor 102 is described by being expressed as a single element. Alternatively, multiple capacitive elements can be arranged by connecting them in parallel.

[0109] 1 to 5, the transistor 101 is described as an n-channel transistor. It is possible to use a p-channel type. The case where 1 is a p-channel type is shown in Figures 25(E) and (F). During the period when the variations in the current characteristics such as the mobility of the transistor 101 are corrected, 1(A) is a diagram similar to FIG. 1(A) showing the conductive and non-conductive states between the lines and the elements; FIG. 25(F) shows a state in which a current is supplied to the display element 105 via the transistor 101. The conductive and non-conductive states between each wiring and each element during this period are shown in the same manner as in FIG. 1(B). As shown in FIGS. 25(E) and 25(F), a p-channel transistor 101 is used. When an EL element is used as the display element 105, an n-channel transistor is used. It is desirable to connect in the opposite direction to when a transistor is used.

[0110] The transistor 101 controls the magnitude of the current flowing through the display element 105. They often have the ability to drive 105.

[0111] In many cases, the wiring 103 has the ability to supply power to the display element 105. Alternatively, the wiring 103 may have the ability to supply a current to the transistor 101. There are many matches.

[0112] Note that the voltage according to the threshold voltage of the transistor 101 is A voltage of the same magnitude as the low voltage or a voltage close to the threshold voltage of transistor 101 For example, if the threshold voltage of the transistor 101 is large, , the voltage according to the threshold voltage is also large, and when the threshold voltage of the transistor 101 is small, In this way, the magnitude is determined according to the threshold voltage. The voltage that appears to be present is called the voltage corresponding to the threshold voltage. The voltage that is slightly different due to the influence of the above is also called the voltage according to the threshold voltage. It is possible.

[0113] The display element 105 has a function of changing the luminance, brightness, reflectance, transmittance, etc. Therefore, examples of the display element 105 include a liquid crystal element, a light emitting element, It is possible to use a device such as an organic EL element, an electrophoretic element, etc. In the explanation and accompanying drawings, the explanation will be made assuming a light emitting element such as an organic EL element. Let's say.

[0114] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0115] (Embodiment 2) Next, in this embodiment, an application example of the circuit and driving method described in the first embodiment will be described. vinegar.

[0116] FIG. 7A shows a specific example of FIG. 1A and FIG. 1B. The terminal is electrically connected to the gate of the transistor 101 and the first terminal of the capacitor 102. The second terminal of the switch 201 is electrically connected to the first terminal of the transistor 101. The first terminal of the switch 202 is connected to the second terminal of the transistor 101 and the capacitance element 10 2, and the second terminal of the switch 202 is electrically connected to the first terminal of the display element 105. The first terminal of the switch 203 is electrically connected to the wiring 103. , and the second terminal of switch 203 is connected to the first terminal of switch 201, transistor 1 The gate of the switch 101 and the first terminal of the capacitor 102 are electrically connected to each other. The first terminal of switch 204 is connected to the first terminal of switch 201, the second terminal of switch 203, and the The gate of the transistor 101 and the first terminal of the capacitor element 102 are electrically connected to each other. The second terminal of 204 is electrically connected to the wiring 104. In this way, four switches are arranged. By placing the connector as shown in Figure 1(A) and Figure 1(B) (or Figure 4(C) and Figure 4(D)), It is possible to realize a circuit configuration that realizes this situation.

[0117] Examples other than that shown in FIG. 7(A) are shown in FIG. 7(B), FIG. 7(C), and FIG. 7(D). In FIG. 7(B), 7A, a switch 205 is newly provided to control the connection with the wiring 206. The configuration shown in FIG. 7C controls the potential of the second terminal of the transistor 101. 7A, a switch 207 is newly provided to control the connection with the wiring 208. The structure shown in FIG. 7D controls the gate potential of the transistor 101. 7B, a switch 207 is newly provided to control the connection with the wiring 208. The potential of the gate of the transistor 101 and the potential of the second terminal of the transistor 101 are controlled. For example, the potential of the wiring 206 or the wiring 208 is changed. 1(A) or 1(B) (or FIG. 4(C) or 4(D)). Furthermore, switches and transistors are not required. If necessary, they will be arranged appropriately.

[0118] 7A to 7D show some examples of the configuration described in the first embodiment. However, other examples can also be configured in the same way.

[0119] Next, the operation method will be described. Here, the circuit shown in Figure 7(A) will be used. A similar method of operation can be used for other circuits.

[0120] First, as shown in FIG. 8A, initialization is performed. This is performed by setting the gate of the transistor 101, Alternatively, it is an operation of setting the drain (or source) potential to a predetermined potential. As a result, the transistor 101 can be turned on. A predetermined voltage is supplied to the capacitor 102. Therefore, a charge is held in the capacitor 102. The switches 201, 202, and 203 are in a conducting state. As for switch 204, it is in a non-conducting state and is therefore off. However, it is not limited to this. However, it is also preferable that no current flows through the display element 105. Therefore, it is desirable to be in a position where this can be realized. At least one of the switches 201, 202, and 203 Preferably, one of the resistors is non-conducting and off.

[0121] In Figures 8(A) to 8(E), the dotted arrows indicate the movement of the charges. However, the present invention is not limited to this, and the potential If it's a relationship, there's no problem.

[0122] Next, as shown in FIG. 8B, the threshold voltage of the transistor 101 is obtained. Switch 201 and switch 203 are in a conductive state and are turned on. The switch 204 is preferably in a non-conductive state and is turned off. Since the charge stored in the capacitor 102 during the period shown in FIG. 8(A) is released, Therefore, the potential of the gate of the transistor 101 is The threshold voltage (positive value) of the transistor 101 is increased from the potential due to the charge stored in the transistor 101. In other words, the absolute value of the threshold voltage of the transistor 101 approaches At this time, the potential between the gate and source of the transistor 101 approaches a potential that is higher by a factor of 1. The voltage approaches the threshold voltage of the transistor 101. The threshold voltage can be obtained between the electrodes at both ends of the element 102.

[0123] During this period, when the charge of the capacitor element 102 is discharged, the period may differ. However, this is not a big problem because after a certain amount of time has passed, the battery will be almost completely discharged. Therefore, even if the length of the period differs, the effect on the operation is small. This operation can be driven using point sequence rather than line sequence. The drive circuit can be realized with a simple configuration. When the pixel is a single pixel, the pixel section is arranged in a matrix and the signal is supplied to the pixel section. The driving circuit section that supplies the signal to the driving circuit section is configured using the same type of transistors. Alternatively, they can be formed on the same substrate. However, this is not limited to this, and they can be formed by using line sequential driving. Alternatively, the pixel portion and the driver circuit portion may be formed on different substrates.

[0124] Next, as shown in FIG. 8(C), a video signal is input. Switch 4 is in a conducting state and is turned on. Switch 201 and switch 203 are in a non-conducting state. The video signal is supplied from the wiring 104. At this time, the charge stored in the capacitor 102 during the period of FIG. Therefore, the charge on the gate of the transistor 101 is further accumulated. The potential is determined by the threshold voltage (positive) of the transistor 101 from the video signal supplied from the wiring 104. That is, the potential of the video signal supplied from the wiring 104 approaches the potential obtained by adding the values ​​of the video signals (the value of the video signal) The potential approaches a potential higher by the absolute value of the threshold voltage of the transistor 101 than the potential at the threshold voltage of the transistor 101. By the operations of FIG. 8(B) and FIG. 8(C), the video signal is input and the threshold voltage is acquired. It is possible.

[0125] Next, as shown in FIG. 8(D), the variation in current characteristics such as the mobility of the transistor 101 is This corresponds to the period shown in Fig. 1(A) and Fig. 4(C). Switch 201 is in a conducting state and is turned on. Preferably, switch 204 is in a non-conducting state and is turned off. By this, the charge stored in the capacitor 102 is discharged through the transistor 101. In this way, by slightly discharging through transistor 101, This makes it possible to reduce the influence of variations in the current of the transistor 101.

[0126] Next, as shown in FIG. 8(E), a current is applied to the display element 105 via the transistor 101. This corresponds to the period shown in Fig. 1(B) and Fig. 4(D). Switch 201, switch 202, is in a conducting state and is turned on. Preferably, transistor 204 is in a non-conducting state and is turned off. The voltage between the gate and source of the transistor 101 is a voltage corresponding to the threshold voltage and a video signal voltage. The voltage obtained by subtracting the voltage according to the current characteristics of the transistor 101 from the sum of the voltages Therefore, the influence of variations in the current characteristics of the transistor 101 can be reduced. The display element 105 can be supplied with a current of an appropriate magnitude.

[0127] As shown in FIGS. 8A to 8E, the variation in current characteristics such as the mobility of the transistor 101 During the period when the charge is corrected (FIG. 1A), the voltage such as the mobility of the transistor 101 is Since the variation in current characteristics is reduced, the period during which current is supplied to the display element 105 (FIG. 1 4(B) and 4(D)), the variation in the current supplied to the display element 105 is also reduced. As a result, the variation in the display state of the display element 105 is reduced, and a high-quality display is achieved. It can be done.

[0128] In the case of the circuit configuration of FIG. 7(B), during the initialization period shown in FIG. 8(A), The potential of the second terminal of the resistor 101 can be controlled. Preferably, the switches 203 and 205 are in a conductive state and are turned on. The switches 202 and 204 are in a non-conducting state and are turned off. It is desirable that the operations from FIG. 8(B) onward are performed in the same manner.

[0129] In the case of the circuit configuration of FIG. 7(C), during the initialization period shown in FIG. 8(A), The potential of the gate of the switch 201 can be controlled. It is desirable that the switches 202 and 207 are in a conductive state and are turned on. The switches 203 and 204 are in a non-conducting state and are turned off. It is desirable that the operations from FIG. 8(B) onward are performed in the same manner.

[0130] In the case of the circuit configuration of FIG. 7(D), during the initialization period shown in FIG. 8(A), It is possible to control the potential of the gate and / or the second terminal of the transistor 101. Therefore, the switches 201, 205, and 207 are in a conductive state and are turned on. Regarding the switches 202, 203, and 204, In this case, it is desirable that the transistor is in a non-conductive state and is turned off. In this case, the same operation can be performed.

[0131] In addition, in FIG. 8(A) to FIG. 8(E), when switching to each operation, It is also possible to provide another operation or another period between the two. For example, in FIG. A state as shown in FIG. 8(A) and FIG. 8(B) may be provided between these periods. However, there is no problem as it does not cause any problems.

[0132] The operations of FIG. 1(C) and FIG. 1(D) are shown in FIG. 10(A) to FIG. 10(E). As for specific operations, the same as in Figures 8(A) to 8(E), the operation is performed after initialization and the like. This can be achieved by:

[0133] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0134] (Embodiment 3) Next, in this embodiment, an application example of the circuit and driving method described in the first embodiment will be described. vinegar.

[0135] FIG. 11A shows a specific example of FIG. 1C and FIG. 1D. The first terminal of the switch 301 is electrically connected to the wiring 103, and the second terminal of the switch 301 is electrically connected to the transistor 10 The gate of the switch 20 is electrically connected to the first terminal of the capacitor 102. 2 is connected to the second terminal of the transistor 101 and the second terminal of the capacitor 102. and electrically connects the second terminal of the switch 202 to the first terminal of the display element 105. Then, the first terminal of the switch 303 is electrically connected to the wiring 103, and the switch The second terminal of the transistor 303 is electrically connected to the first terminal of the transistor 101. The first terminal of switch 204 is connected to the second terminal of switch 301, and the gate of transistor 101 is connected to the , and the first terminal of the capacitor 102, and the second terminal of the switch 204. The four switches are electrically connected to the line 104. It is possible to realize a circuit configuration that realizes the connection state of Figure 1(C) and Figure 1(D).

[0136] Examples other than that shown in FIG. 11(A) are shown in FIG. 11(B), FIG. 11(C), and FIG. 11(D). In (B), a switch 305 is newly provided in FIG. 11(A) to control the connection with the wiring 306. 10 shows a structure in which the potential of the second terminal of the transistor 101 is controlled by using the transistor 102 . In FIG. 11C, a switch 307 is newly provided in FIG. 11A, and the connection with the wiring 308 is 1 shows a configuration in which the potential of the gate of the transistor 101 is controlled by controlling the In FIG. 11(D), a switch 307 is newly provided in FIG. 11(B), and the connection with the wiring 308 is By controlling For example, the wiring 306 or the wiring 307 is By changing the potential of O8, the same operation as in Figure 1(C) or Figure 1(D) can be achieved. If more switches or transistors are needed, they can be arranged appropriately. It will be placed.

[0137] 11A to 11D show an example of the configuration described in the first embodiment. However, other examples can be configured in the same way.

[0138] Next, the operation method will be described. Here, the circuit shown in Figure 11(A) will be used. A similar operation method can be used for circuits other than those described above.

[0139] First, as shown in FIG. 12A, initialization is performed. This is performed by Or, it is an operation of setting the drain (or source) potential to a predetermined potential. This allows the transistor 101 to be turned on. A predetermined voltage is supplied to the capacitor 102. Therefore, a charge is held in the capacitor 102. The switches 301, 202, and 303 are in a conducting state. , is turned on. As for switch 204, it is in a non-conducting state and is turned off. However, it is not limited to this. However, it is also possible to prevent a current from flowing through the display element 105. It is desirable to have a system in place that allows this to happen. , at least one of the switches 301, 202, and 303 One is preferably in a non-conducting state and turned off.

[0140] In Figures 12(A) to 12(E), the dotted arrows indicate the movement of the charges. However, the present invention is not limited to this, and may be applied to any other type of device that performs a predetermined drive. There is no problem if it is a rank relationship, etc.

[0141] Next, as shown in FIG. 12(B), the threshold voltage of the transistor 101 is obtained. Switch 301 and switch 303 are in a conductive state and are turned on. , the switch 204 is preferably in a non-conductive state and is turned off. Since the capacitor 102 has charges accumulated during the period shown in FIG. 12(A), the charges Therefore, the potential of the gate of the transistor 101 becomes The threshold voltage (positive value) of the transistor 101 is determined from the potential due to the charge stored between the ) approaches the sum of the threshold voltages of the transistor 101. At this time, the gate and source of the transistor 101 The voltage between the transistors 101 and 102 approaches the threshold voltage of the transistor 101. The threshold voltage can be obtained between the electrodes at both ends of the capacitor 102 .

[0142] During this period, when the charge of the capacitor element 102 is discharged, the period may differ. However, this is not a big problem because after a certain amount of time has passed, the battery will be almost completely discharged. Therefore, even if the length of the period differs, the effect on the operation is small. This operation can be driven using point sequence rather than line sequence. The drive circuit can be realized with a simple configuration. Therefore, the circuit shown in FIG. When a pixel is considered as one, the pixel part is arranged in a matrix and a signal is sent to the pixel part. The driving circuit unit that supplies the signal is configured using the same type of transistors. Alternatively, it is possible to form the display devices on the same substrate. However, this is not limitative, and the display devices may be driven line by line. Alternatively, the pixel portion and the driver circuit portion may be formed on different substrates.

[0143] Next, as shown in FIG. 12(C), a video signal is input. Switch 301 and switch 303 are in a non-conductive state. It is desirable that the image signal is turned off. At this time, the capacitance element 102 receives the charge stored in the period of FIG. Therefore, the gate of transistor 101 The potential of the transistor 101 is determined by the threshold voltage of the transistor 101 from the video signal supplied from the wiring 104. In other words, the potential of the image supplied from the wiring 104 approaches the potential obtained by adding the The potential approaches a potential higher than the signal by the absolute value of the threshold voltage of the transistor 101. The operation of Figure 12(B) and Figure 12(C) inputs the video signal and acquires the threshold voltage. It is possible to do the following.

[0144] Next, as shown in FIG. 12(D), the variation in current characteristics such as the mobility of the transistor 101 is This corresponds to the period shown in FIG. 1(C). Switch 303 is in a conducting state and is turned on. It is desirable that the transistor is in a non-conducting state and is turned off. As a result, the charge stored in the capacitor 102 is discharged through the transistor 101. In this way, a small discharge through transistor 101 This can reduce the influence of variations in the current of the resistor 101.

[0145] Next, as shown in FIG. 12(E), a current is supplied to the display element 105 via the transistor 101. This corresponds to the period shown in FIG. 1(D). Switch 303 is in a conductive state and is turned on. At this time, the transistor 101 is in a non-conducting state and is preferably off. The voltage between the gate and source of the transistor is the sum of the voltage corresponding to the threshold voltage and the video signal voltage. The voltage obtained by subtracting a voltage according to the current characteristics of the transistor 101 from the Therefore, the influence of variations in the current characteristics of the transistor 101 can be reduced, and the display The element 105 can be supplied with a current of any suitable magnitude.

[0146] As shown in FIGS. 12A to 12E, the current characteristics such as the mobility of the transistor 101 are During the period when the fluctuation is corrected (FIG. 1C), the mobility of the transistor 101, etc. Since the variation in the current characteristics is reduced, the period during which the current is supplied to the display element 105 (FIG. 1(D)), the variation in the current supplied to the display element 105 is also reduced. As a result, the variation in the display state of the display element 105 is reduced, and high-quality display can be achieved. Yes, it is possible.

[0147] In the case of the circuit configuration of FIG. 11(B), during the initialization period shown in FIG. 12(A), It is possible to control the potential of the second terminal of the transistor 101. 01, switch 303, and switch 305 are in a conductive state and are turned on. The switches 202 and 204 are in a non-conducting state and are turned off. It is desirable that the operation is the same as that of Figure 12(B) onwards. stomach.

[0148] In the case of the circuit configuration of FIG. 11(C), during the initialization period shown in FIG. 12(A), It is possible to control the potential of the gate of the transistor 101. It is desirable that the switches 303 and 307 are in a conductive state and turned on. The switches 301 and 204 are in a non-conducting state and are turned off. It is desirable that the operations from FIG. 12(B) onward are performed in the same manner.

[0149] In the case of the circuit configuration of FIG. 11(D), during the initialization period shown in FIG. 12(A), The potential of the gate and / or the second terminal of the transistor 101 can be controlled. The switches 303, 305, and 307 are in a conductive state. It is desirable that the switches 202, 203, and 204 are turned on. It is desirable that the transistors are in a non-conducting state and are turned off. The subsequent operations may be performed in the same manner.

[0150] In addition, in Fig. 12(A) to Fig. 12(E), when switching to each operation, It is also possible to provide another operation or another period between the operations. For example, as shown in FIG. A state as shown in C) may be provided between FIG. 12(A) and FIG. 12(B). There is no problem with setting a period, as it will not cause any problems.

[0151] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0152] (Fourth embodiment) Next, in this embodiment, an application example of the circuit and driving method described in the first embodiment will be described. vinegar.

[0153] FIG. 13A shows a specific example of FIG. 5A and FIG. 5B. The terminal of the transistor 101 is electrically connected to the gate of the transistor 101 and the first terminal of the capacitor 102. , the second terminal of the switch 401 is connected to the first terminal of the transistor 101 and the The first terminal of the switch 403 is electrically connected to the wiring 103. 403 is electrically connected to the first terminal of the transistor 101 and the second terminal of the switch 403 is electrically connected to the first terminal of the transistor 101. The first terminal of the switch 204 is electrically connected to the second terminal of the switch 401. The first terminal of the switch 401, the gate of the transistor 101, and the first terminal of the capacitor 102 and electrically connects the second terminal of the switch 204 to the wiring 104. In this way, by placing four switches, the connection state of Fig. 5(A) and Fig. 5(B) can be realized. It is possible to realize a circuit configuration that realizes this situation.

[0154] Examples other than that shown in FIG. 13(A) are shown in FIG. 13(B), FIG. 13(C), and FIG. 13(D). In (B), a switch 405 is newly provided in FIG. 13(A) to control the connection with the wiring 406. 10 shows a structure in which the potential of the second terminal of the transistor 101 is controlled by using the transistor 102 . In FIG. 13C, a switch 407 is newly provided in FIG. 13A, and the connection with the wiring 408 is 1 shows a configuration in which the potential of the gate of the transistor 101 is controlled by controlling the In FIG. 13(D), a switch 407 is newly provided in FIG. 13(B), and the connection with the wiring 408 is By controlling For example, the wiring 406 or the wiring 4 By changing the potential of O8, the same operation as in Figure 5(A) or Figure 5(B) can be realized. If more switches or transistors are needed, they can be arranged appropriately. It will be placed.

[0155] 13A to 13D show an example of the configuration described in the first embodiment. However, other examples can be configured in the same way.

[0156] Next, the operation method will be described. Here, the circuit shown in Figure 13(A) will be used. A similar operation method can be used for circuits other than those described above.

[0157] First, as shown in FIG. 14A, initialization is performed. This is performed by Or, it is an operation of setting the drain (or source) potential to a predetermined potential. This allows the transistor 101 to be turned on. A predetermined voltage is supplied to the capacitor 102. Therefore, a charge is held in the capacitor 102. The switches 401 and 403 are in a conductive state and are turned on. It is desirable that the switch 204 is in a non-conducting state and is turned off. In addition, during the initialization period in FIG. 14A, the potential of the wiring 103 is lower than that of the other wirings. However, it is not limited to this. However, when a current flows through the display element 105, It is desirable that this does not happen, so it is desirable that the situation be such that this can be realized. Therefore, it is desirable that at least the voltage applied to the light emitting element is reverse bias. .

[0158] In Figures 14(A) to 14(E), the dotted arrows indicate the movement of the charges. However, the present invention is not limited to this, and may be applied to any other type of device that performs a predetermined drive. There is no problem if it is a rank relationship, etc.

[0159] Next, as shown in FIG. 14B, the threshold voltage of the transistor 101 is obtained. Switch 401 and switch 403 are in a conductive state and are turned on. It is desirable that the transistor in FIG. 14(B) is in a non-conducting state and is turned off. During the period in which the threshold voltage of the transistor 101 is acquired, the potential of the wiring 103 is the potential of the initialization period. At this time, the capacitor 102 has a capacitance in the period shown in FIG. There is a charge stored in the transistor, and that charge is discharged. The potential of the gate of 101 is determined by the potential due to the charge accumulated during the period of FIG. 14(A), as follows: The potential approaches the sum of the threshold voltages (positive values) of the transistors 101. Therefore, the potential approaches a potential higher by the absolute value of the threshold voltage of the transistor 101. When the voltage between the gate and source of transistor 101 is equal to the threshold voltage of transistor 101, These operations cause a voltage between the electrodes at both ends of the capacitance element 102 to approach the threshold voltage. It is possible to obtain the voltage value.

[0160] During this period, when the charge of the capacitor element 102 is discharged, the period may differ. However, this is not a big problem because after a certain amount of time has passed, the battery will be almost completely discharged. Therefore, even if the length of the period differs, the effect on the operation is small. This operation can be driven using point sequence rather than line sequence. The drive circuit can be realized with a simple configuration. Therefore, the circuit shown in FIG. When a pixel is considered as one, the pixel part is arranged in a matrix and a signal is sent to the pixel part. The driving circuit unit that supplies the signal is configured using the same type of transistors. Alternatively, it is possible to form the display devices on the same substrate. However, this is not limitative, and the display devices may be driven line by line. Alternatively, the pixel portion and the driver circuit portion may be formed on different substrates.

[0161] Next, as shown in Fig. 14(C), a video signal is input. The switch 204 is in a conductive state. The switches 401 and 403 are in a non-conducting state and are turned on. In addition, during the video signal input period shown in FIG. 14(C), It is desirable that the potential of the wiring 103 is higher than the potential input to the other wirings. A video signal is supplied from 104. At this time, the capacitor 102 has the voltage as shown in FIG. Since there is a charge accumulated between them, the charge is further accumulated. The potential of the gate of the transistor 101 is determined by the video signal supplied from the wiring 104. The potential approaches the sum of the threshold voltages (positive values) of the wiring 101 and the The absolute value of the threshold voltage of transistor 101 is larger than the video signal supplied by 04. The operation of Figure 14(B) and Figure 14(C) causes the input of the video signal and obtaining the threshold voltage.

[0162] Next, as shown in FIG. 14(D), the variation in current characteristics such as the mobility of the transistor 101 is This corresponds to the period shown in FIG. 5(A). Switch 403 is in a conducting state and is turned on. Switch 204 is in a non-conducting state. It is desirable that the transistor 101 is turned off. During the period when the variations in current characteristics such as the voltage are corrected, the potential of the wiring 103 is not input to other wirings. It is desirable to set the potential higher than the potential applied to the capacitor. The charge stored in the capacitor 102 is discharged through the transistor 101. By discharging a small amount through transistor 101, This can reduce the influence of current variations.

[0163] Next, as shown in FIG. 14(E), a current is supplied to the display element 105 via the transistor 101. This corresponds to the period shown in FIG. 5(B). The switches 401 and 204 are in a non-conducting state. It is desirable that the transistor 101 in FIG. During the period when a current is supplied to the display element 105, the potential of the wiring 103 is input to another wiring. At this time, the potential between the gate and source of the transistor 101 is preferably higher than the potential at which the transistor 101 is turned on. The voltage between the transistors is determined by the sum of the voltage according to the threshold voltage and the video signal voltage. This voltage is the voltage from which the voltage according to the current characteristics of the transistor 101 is subtracted. The influence of variations in the current characteristics of the transistor 101 can be reduced, and the display element 105 , it is possible to supply a current of an appropriate magnitude.

[0164] As shown in FIGS. 14A to 14E, the current characteristics such as the mobility of the transistor 101 are During the period when the fluctuation is corrected (FIG. 5A), the mobility of the transistor 101, etc. Since the variation in the current characteristics is reduced, the period during which the current is supplied to the display element 105 (FIG. 5(B)), the variation in the current supplied to the display element 105 is also reduced. As a result, the variation in the display state of the display element 105 is reduced, and high-quality display can be achieved. Yes, it is possible.

[0165] In the case of the circuit configuration of FIG. 13(B), during the initialization period shown in FIG. 14(A), It is possible to control the potential of the second terminal of the transistor 101. 01, switch 403, and switch 405 are in a conductive state and are turned on. It is desirable that the switch 204 is in a non-conducting state and is turned off. It is preferable that the operations from FIG. 14(B) onward are performed in the same manner.

[0166] In the case of the circuit configuration of FIG. 13(C), during the initialization period shown in FIG. 14(A), It is possible to control the potential of the gate of the transistor 101. Switch 407 is preferably in a conductive state and turned on. It is desirable that the switch 201 and the switch 204 are in a non-conducting state and are turned off. Note that the operations from FIG. 14(B) onward can be performed in the same manner.

[0167] In the case of the circuit configuration of FIG. 13(D), during the initialization period shown in FIG. 14(A), The potential of the gate and / or the second terminal of the transistor 101 can be controlled. The switches 403, 405, and 407 are in a conductive state. It is desirable that the switches 401 and 204 are non-conductive. It is desirable that the power is on and the power is off. It should operate in the same way.

[0168] In addition, in Fig. 14(A) to Fig. 14(E), when switching to each operation, It is also possible to provide another operation or another period between the operations. For example, as shown in FIG. A state as shown in C) may be provided between FIG. 14(A) and FIG. 14(B). There is no problem with setting a period, as it will not cause any problems.

[0169] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0170] (Embodiment 5) Next, in this embodiment, an application example of the circuit and driving method described in the first embodiment will be described. vinegar.

[0171] FIG. 15(A) shows a specific example different from that of the fourth embodiment shown in FIGS. 5(A) and 5(B). The first terminal of the switch 501 is connected to the gate of the transistor 101 and the first terminal of the capacitor 102. the second terminal of the switch 501 and the second terminal of the switch 503. is electrically connected to the first terminal of the transistor 101. The first terminal of the switch 503 is electrically connected to the wiring 103, and the second terminal of the switch 503 is electrically connected to the transistor 10 1, the first terminal of the capacitor 102, and the first terminal of the switch 501. Then, the first terminal of the switch 204 is connected to the first terminal of the switch 501, The gate of the transistor 101 and the first terminal of the capacitor element 102 are electrically connected to the switch 2. The second terminal of switch 04 is electrically connected to wiring 104. In this way, four switches are arranged. By doing so, a circuit configuration that realizes the connection status of Figure 5(A) and Figure 5(B) can be realized. It is possible to do this.

[0172] Examples other than that shown in FIG. 15(A) are shown in FIG. 15(B), FIG. 15(C), and FIG. 15(D). In (B), a switch 505 is newly provided in FIG. 15(A) to control the connection with a wiring 506. 10 shows a structure in which the potential of the second terminal of the transistor 101 is controlled by using the transistor 102 . In FIG. 15(C), a switch 507 is newly provided in FIG. 15(A) and the connection with the wiring 508 is 1 shows a configuration in which the potential of the gate of the transistor 101 is controlled by controlling the In FIG. 15(D), a switch 507 is newly provided in FIG. 15(B), and a connection with a wiring 508 is made. By controlling For example, the wiring 506 or the wiring 507 is By changing the potential of O8, the same operation as in Figure 5(A) or Figure 5(B) can be realized. If more switches or transistors are needed, they can be arranged appropriately. It will be placed.

[0173] 15(A) to 15(D) show an example of the configuration described in the first embodiment. However, other examples can be configured in the same way.

[0174] Next, the operation method will be described. Here, the circuit shown in Figure 15(A) will be used. A similar operation method can be used for circuits other than those described above.

[0175] First, as shown in FIG. 16A, initialization is performed. This is performed by Or, it is an operation of setting the drain (or source) potential to a predetermined potential. This allows the transistor 101 to be turned on. A predetermined voltage is supplied to the capacitor 102. Therefore, a charge is held in the capacitor 102. The switches 501 and 503 are in a conductive state and are turned on. It is desirable that the switch 204 is in a non-conducting state and is turned off. In addition, during the initialization period in FIG. 16A, the potential of the wiring 103 is lower than that of the other wirings. However, it is not limited to this. However, when a current flows through the display element 105, It is desirable that this does not happen, so it is desirable that the situation be such that this can be realized. Therefore, it is desirable that at least the voltage applied to the light emitting element is reverse bias. .

[0176] In Figures 16(A) to 16(E), the dotted arrows indicate the movement of the charges. However, the present invention is not limited to this, and may be applied to any other type of device that performs a predetermined drive. There is no problem if it is a rank relationship, etc.

[0177] Next, as shown in FIG. 16(B), the threshold voltage of the transistor 101 is obtained. Switch 501 and switch 503 are in a conductive state and are turned on. It is desirable that the transistor in FIG. 16(B) is in a non-conducting state and is turned off. During the period in which the threshold voltage of the transistor 101 is acquired, the potential of the wiring 103 is the potential of the initialization period. At this time, the capacitor 102 has a capacitance in the period shown in FIG. There is a charge stored in the transistor, and that charge is discharged. The potential of the gate of 101 is determined by the potential due to the charge accumulated during the period of FIG. 16(A), as follows: The potential approaches the sum of the threshold voltages (positive values) of the transistors 101. Therefore, the potential approaches a potential higher by the absolute value of the threshold voltage of the transistor 101. When the voltage between the gate and source of transistor 101 is equal to the threshold voltage of transistor 101, These operations cause a voltage between the electrodes at both ends of the capacitance element 102 to approach the threshold voltage. It is possible to obtain the voltage value.

[0178] During this period, when the charge of the capacitor element 102 is discharged, the period may differ. However, this is not a big problem because after a certain amount of time has passed, the battery will be almost completely discharged. Therefore, even if the length of the period differs, the effect on the operation is small. This operation can be driven using point sequence rather than line sequence. The drive circuit can be realized with a simple configuration. Therefore, the circuit shown in FIG. When a pixel is considered as one, the pixel part is arranged in a matrix and a signal is sent to the pixel part. The driving circuit unit that supplies the signal is configured using the same type of transistors. Alternatively, it is possible to form the display devices on the same substrate. However, this is not limitative, and the display devices may be driven line by line. Alternatively, the pixel portion and the driver circuit portion may be formed on different substrates.

[0179] Next, as shown in Fig. 16(C), a video signal is input. The switch 204 is in a conductive state. The switches 501 and 503 are in a non-conducting state and are turned on. In addition, during the video signal input period shown in FIG. 16(C), It is desirable that the potential of the wiring 103 is higher than the potential input to the other wirings. A video signal is supplied from 104. At this time, the capacitor 102 has the voltage as shown in FIG. Since there is a charge accumulated between them, the charge is further accumulated. The potential of the gate of the transistor 101 is determined by the video signal supplied from the wiring 104. The potential approaches the sum of the threshold voltages (positive values) of the wiring 101 and the The absolute value of the threshold voltage of transistor 101 is larger than the video signal supplied by 04. The operation of Figure 16(B) and Figure 16(C) causes the input of the video signal and obtaining the threshold voltage.

[0180] Next, as shown in FIG. 16(D), the variation in current characteristics such as the mobility of the transistor 101 is This corresponds to the period shown in FIG. 5(A). Switch 503 is in a conducting state and is turned on. Switch 204 is in a non-conducting state. It is desirable that the transistor 101 is turned off. During the period when the variations in current characteristics such as the voltage are corrected, the potential of the wiring 103 is not input to other wirings. It is desirable to set the potential higher than the potential applied to the capacitor. The charge stored in the capacitor 102 is discharged through the transistor 101. By discharging a small amount through transistor 101, This can reduce the influence of current variations.

[0181] Next, as shown in FIG. 16(E), a current is supplied to the display element 105 via the transistor 101. This corresponds to the period shown in FIG. 5B. Switch 503 is in a conducting state and is turned on. Switch 204 is in a non-conducting state and is turned on. It is desirable that the transistor 101 in FIG. During the period when a current is supplied to the display element 105, the potential of the wiring 103 is input to another wiring. At this time, the potential between the gate and source of the transistor 101 is preferably higher than the potential at which the transistor 101 is turned on. The voltage between the transistors is determined by the sum of the voltage according to the threshold voltage and the video signal voltage. This voltage is the voltage from which the voltage according to the current characteristics of the transistor 101 is subtracted. The influence of variations in the current characteristics of the transistor 101 can be reduced, and the display element 105 , it is possible to supply a current of an appropriate magnitude.

[0182] As shown in FIGS. 16A to 16E, the current characteristics such as the mobility of the transistor 101 are During the period when the fluctuation is corrected (FIG. 5A), the mobility of the transistor 101, etc. Since the variation in the current characteristics is reduced, the period during which the current is supplied to the display element 105 (FIG. 5(B)), the variation in the current supplied to the display element 105 is also reduced. As a result, the variation in the display state of the display element 105 is reduced, and high-quality display can be achieved. Yes, it is possible.

[0183] In the case of the circuit configuration of FIG. 15(B), during the initialization period shown in FIG. 16(A), It is possible to control the potential of the second terminal of the transistor 101. 01, switch 503, and switch 505 are in a conductive state and are turned on. It is desirable that the switch 204 is in a non-conducting state and is turned off. It is preferable that the operations from FIG. 16(B) onward are performed in the same manner.

[0184] In the case of the circuit configuration of FIG. 15(C), during the initialization period shown in FIG. 16(A), It is possible to control the potential of the gate of the transistor 101. It is desirable that the switches 503 and 507 are in a conductive state and turned on. It is preferable that the switch 204 is in a non-conducting state and is turned off. Note that the operations from FIG. 16(B) onward can be performed in the same manner.

[0185] In the case of the circuit configuration of FIG. 15(D), during the initialization period shown in FIG. 16(A), The potential of the gate and / or the second terminal of the transistor 101 can be controlled. The switches 501, 503, 505, and 407 are As for switch 204, it is desirable that it is in a non-conducting state. It is desirable that the power is turned off. Just operate it as follows.

[0186] In addition, in Fig. 16(A) to Fig. 16(E), when switching to each operation, It is also possible to provide another operation or another period between the operations. For example, as shown in FIG. A state as shown in C) may be provided between FIG. 16(A) and FIG. 16(B). There is no problem with setting a period, as it will not cause any problems.

[0187] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0188] (Sixth embodiment) Next, in this embodiment, an application example of the circuit and driving method described in the first embodiment will be described. vinegar.

[0189] FIG. 17A shows a specific example of FIG. 5C and FIG. 5D. The first terminal of the switch 601 is electrically connected to the wiring 103, and the second terminal of the switch 601 is electrically connected to the transistor 10 The gate of the switch 60 is electrically connected to the first terminal of the capacitor 102. The first terminal of the switch 603 is electrically connected to the wiring 103, and the second terminal of the switch 603 is connected to the transistor The first terminal of the switch 204 is electrically connected to the first terminal of the switch 101. The first terminal of the switch 601, the gate of the transistor 101, and the first terminal of the capacitor 102 are connected to each other. The second terminal of the switch 204 is electrically connected to the wiring 104 . In this way, by placing four switches, the connection status of Fig. 5(C) and Fig. 5(D) can be realized. It is possible to realize a circuit configuration that realizes the above.

[0190] Examples other than that shown in Figure 17(A) are shown in Figures 17(B), 17(C), and 17(D). In (B), a switch 605 is newly provided in FIG. 17(A) to control the connection with a wiring 606. 10 shows a structure in which the potential of the second terminal of the transistor 101 is controlled by using the transistor 102 . In FIG. 17C, a switch 607 is newly provided in FIG. 17A, and the connection with the wiring 608 is 1 shows a configuration in which the potential of the gate of the transistor 101 is controlled by controlling the In FIG. 17(D), a switch 607 is newly provided in FIG. 17(B), and the connection with the wiring 608 is By controlling For example, the wiring 606 or the wiring 6 By changing the potential of O8, the same operation as in Figure 5(C) or Figure 5(D) can be realized. If more switches or transistors are needed, they can be arranged appropriately. It will be placed.

[0191] 17(A) to 17(D) show an example of the configuration described in the first embodiment. However, other examples can be configured in the same way.

[0192] Next, the operation method will be described. Here, the circuit shown in Figure 17(A) will be used. A similar operation method can be used for circuits other than those described above.

[0193] First, as shown in FIG. 18A, initialization is performed. This is performed by Or, it is an operation of setting the drain (or source) potential to a predetermined potential. This allows the transistor 101 to be turned on. A predetermined voltage is supplied to the capacitor 102. Therefore, a charge is held in the capacitor 102. The switches 601 and 603 are in a conductive state and are turned on. It is desirable that the switch 204 is in a non-conducting state and is turned off. In addition, during the initialization period in FIG. 18A, the potential of the wiring 103 is lower than that of the other wirings. However, it is not limited to this. However, when a current flows through the display element 105, It is desirable that this does not happen, so it is desirable that the situation be such that this can be realized. Therefore, it is desirable that at least the voltage applied to the light emitting element is reverse bias. .

[0194] In Figures 18(A) to 18(E), the dotted arrows indicate the movement of the charges. However, the present invention is not limited to this, and may be applied to any other type of device that performs a predetermined drive. There is no problem if it is a rank relationship, etc.

[0195] Next, as shown in FIG. 18B, the threshold voltage of the transistor 101 is obtained. Switch 601 and switch 603 are in a conductive state and are turned on. It is desirable that the transistor in FIG. 18(B) is in a non-conducting state and is turned off. During the period in which the threshold voltage of the transistor 101 is acquired, the potential of the wiring 103 is the potential of the initialization period. At this time, the capacitor 102 has a capacitance in the period shown in FIG. There is a charge stored in the transistor, and that charge is discharged. The potential of the gate of 101 is determined by the potential due to the charge accumulated during the period of FIG. 18(A), as follows: The potential approaches the sum of the threshold voltages (positive values) of the transistors 101. Therefore, the potential approaches a potential higher by the absolute value of the threshold voltage of the transistor 101. When the voltage between the gate and source of transistor 101 is equal to the threshold voltage of transistor 101, These operations cause a voltage between the electrodes at both ends of the capacitance element 102 to approach the threshold voltage. It is possible to obtain the voltage value.

[0196] During this period, when the charge of the capacitor element 102 is discharged, the period may differ. However, this is not a big problem because after a certain amount of time has passed, the battery will be almost completely discharged. Therefore, even if the length of the period differs, the effect on the operation is small. This operation can be driven using point sequence rather than line sequence. The drive circuit can be realized with a simple configuration. Therefore, the circuit shown in FIG. When a pixel is considered as one, the pixel part is arranged in a matrix and a signal is sent to the pixel part. The driving circuit unit that supplies the signal is configured using the same type of transistors. Alternatively, it is possible to form the display devices on the same substrate. However, this is not limitative, and the display devices may be driven line by line. Alternatively, the pixel portion and the driver circuit portion may be formed on different substrates.

[0197] Next, as shown in Fig. 18(C), a video signal is input. The switch 204 is in a conductive state. The switches 601 and 603 are in a non-conducting state and are turned on. In addition, during the video signal input period shown in FIG. 18(C), It is desirable that the potential of the wiring 103 is higher than the potential input to the other wirings. A video signal is supplied from 104. At this time, the capacitor 102 has the voltage as shown in FIG. Since there is a charge accumulated between them, the charge is further accumulated. The potential of the gate of the transistor 101 is determined by the video signal supplied from the wiring 104. The potential approaches the sum of the threshold voltages (positive values) of the wiring 101 and the The absolute value of the threshold voltage of transistor 101 is larger than the video signal supplied by 04. The operation of Figure 18(B) and Figure 18(C) causes the input of the video signal and obtaining the threshold voltage.

[0198] Next, as shown in FIG. 18(D), the variation in current characteristics such as the mobility of the transistor 101 is This corresponds to the period shown in FIG. 5(C). Switch 603 is in a conducting state and is turned on. Switch 204 is in a non-conducting state. It is desirable that the transistor 101 is turned off. During the period when the variations in current characteristics such as the voltage are corrected, the potential of the wiring 103 is not input to other wirings. It is desirable to set the potential higher than the potential applied to the capacitor. The charge stored in the capacitor 102 is discharged through the transistor 101. By discharging a small amount through transistor 101, This can reduce the influence of current variations.

[0199] Next, as shown in FIG. 18(E), a current is supplied to the display element 105 via the transistor 101. This corresponds to the period shown in FIG. 5(D). Switch 603 is in a conducting state and is turned on. Switch 204 is in a non-conducting state and is turned on. It is desirable that the transistor 101 in FIG. During the period when a current is supplied to the display element 105, the potential of the wiring 103 is input to another wiring. At this time, the potential between the gate and source of the transistor 101 is preferably higher than the potential at which the transistor 101 is turned on. The voltage between the transistors is determined by the sum of the voltage according to the threshold voltage and the video signal voltage. This voltage is the voltage from which the voltage according to the current characteristics of the transistor 101 is subtracted. The influence of variations in the current characteristics of the transistor 101 can be reduced, and the display element 105 , it is possible to supply a current of an appropriate magnitude.

[0200] As shown in FIGS. 18A to 18E, the current characteristics such as the mobility of the transistor 101 are During the period when the fluctuation is corrected (FIG. 5C), the mobility of the transistor 101, etc. Since the variation in the current characteristics is reduced, the period during which the current is supplied to the display element 105 (FIG. 5(D)), the variation in the current supplied to the display element 105 is also reduced. As a result, the variation in the display state of the display element 105 is reduced, and high-quality display can be achieved. Yes, it is possible.

[0201] In the case of the circuit configuration of FIG. 17(B), during the initialization period shown in FIG. 18(A), It is possible to control the potential of the second terminal of the transistor 101. 01, switch 603, and switch 605 are in a conductive state and are turned on. It is desirable that the switch 204 is in a non-conducting state and is turned off. It is preferable that the operations from FIG. 18(B) onward are performed in the same manner.

[0202] In the case of the circuit configuration of FIG. 17(C), during the initialization period shown in FIG. 18(A), It is possible to control the potential of the gate of the transistor 101. It is desirable that the switches 603 and 607 are in a conductive state and turned on. It is preferable that the switch 204 is in a non-conducting state and is turned off. Note that the operations from FIG. 18(B) onward can be performed in the same manner.

[0203] In the case of the circuit configuration of FIG. 17(D), during the initialization period shown in FIG. 18(A), The potential of the gate and / or the second terminal of the transistor 101 can be controlled. Switch 601, switch 603, switch 605, and switch 607 are As for switch 204, it is desirable that it is in a non-conducting state. It is desirable that the power is turned off. Just operate it as follows.

[0204] In addition, in Figures 18(A) to 18(E), when switching to each operation, It is also possible to provide another operation or another period between the operations. For example, as shown in FIG. A state as shown in C) may be provided between FIG. 18(A) and FIG. 18(B). There is no problem with setting a period, as it will not cause any problems.

[0205] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0206] (Embodiment 7) In this embodiment mode, specific examples of the circuits described in Embodiment Modes 1 to 6 will be described. .

[0207] For example, the circuit shown in Figure 2(A) constitutes one pixel, and the pixels are arranged in a matrix. An example in which the switch is configured as an n-channel However, this is not limited to this, and transistors of other polarities may also be used. transistors, transistors of both polarities, diodes or diodes It is also possible to use a hard-connected transistor.

[0208] The circuit shown in FIG. 2A constitutes one pixel, pixel 1200M. Pixels with the same configuration as 00M are pixel 1200N, pixel 1200P, and pixel 1200Q. , arranged in a matrix. Each pixel is connected to the same wiring depending on the top / bottom and left / right arrangement. It may be connected.

[0209] Next, the correspondence between each element in FIG. 2(A) and each element in pixel 1200M is shown below. The wiring 104 corresponds to the wiring 104M, the wiring 103 corresponds to the wiring 103M, and the switch 201 corresponds to transistor 201M, and switch 202 corresponds to transistor 202M. The transistor 101 corresponds to the transistor 101M, and the switch 203 corresponds to the transistor 101M. The switch 204 corresponds to a transistor 204M, and the capacitance The element 102 corresponds to a capacitive element 102M, and the display element 105 corresponds to a light-emitting element 105M. , the wiring 106 corresponds to the wiring 106M.

[0210] The gate of the transistor 201M is connected to the wiring 1204M. The gate of transistor 203M is connected to wiring 1203M. The gate of the transistor 204M is connected to the wiring 1201M. is connected.

[0211] The wiring connected to the gate of each transistor is a wiring of another pixel or the same It is possible to connect it to another wire of the pixel.

[0212] The wiring 106M may be connected to the wiring 106P, the wiring 106N, and the wiring 106Q. It is possible.

[0213] As with FIG. 19, various circuits can be configured.

[0214] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0215] (Embodiment 8) Next, another example of the configuration of the display device and a method of driving the same will be described. In this case, an image that interpolates the movement of an image (input image) input from outside the display device is generated by multiple The image is generated inside the display device based on the input image, and the generated image (generated image) and the input The generated image is displayed by compensating for the movement of the input image. By creating an image that looks like it's moving between the two, you can make the movement of the video smoother, and This can improve the problem of video quality being reduced by afterimages caused by video drive. The display of moving images ideally involves changing the brightness of each pixel in real time. This is achieved by controlling the pixels in real time, but the real-time individual control of the pixels is The problem of the huge number of paths, the problem of wiring space, and the huge amount of input image data Therefore, it is difficult to realize the display of moving images on a display device. The display is made to look like a moving image by displaying multiple still images in sequence at a regular interval. This period (called the input image signal period in this embodiment, T in and For example, the NTSC standard is 1 / 60 seconds, and the PAL standard is 1 Even with this period, the CRT, which is an impulse type display device, shows no movement. However, there were no problems with the image display. If a video conforming to this standard is displayed as is, it may be displayed incorrectly due to afterimages caused by the fact that it is a hold type. This causes a problem called hold blur. Blurred images are caused by the inconsistency between the human eye's unconscious movement interpolation and the hold-type display. Since it is recognized by discrepancy, it is easier to recognize input image signals than conventional standards. This can be reduced by shortening the signal cycle (approaching real-time individual control of pixels). However, shortening the input image signal cycle will require changes to the standard and will also increase the amount of data. However, it is difficult to do this based on a standardized input image signal. An image that interpolates the movement of the input image is generated inside the display device, and the generated image By interpolating the input image and displaying it, it is possible to hold the image without changing the standard or increasing the amount of data. In this way, the image signal is generated inside the display device based on the input image signal. The process of interpolating the motion of the input image is called video interpolation.

[0216] The moving image interpolation method according to this embodiment can reduce the blurring of the moving image. The moving image interpolation method in the embodiment can be divided into an image generation method and an image display method. And, for specific patterns of movement, different image generation methods and / or image display methods are used. By using this method, motion blur can be effectively reduced. FIG. 10B is a schematic diagram illustrating an example of a moving image interpolation method according to the present embodiment. In Figures 20(A) and (B), the horizontal axis represents time, and the horizontal position represents The part marked "Input" indicates the timing at which each image is handled. Here, the two images that are adjacent in time are The focus is on the image 5121 and the image 5122. The input image has a period T in Enter at intervals of In addition, the period T in The length of one frame is referred to as one frame period. The part marked "Generation" indicates the timing at which a new image is generated from the input image signal. Here, the generated image is based on the image 5121 and the image 5122. The part marked "display" indicates that the image is displayed on the display device. This shows the timing when the image is displayed. Although it is only indicated by a dashed line, by treating it in the same way as the image of interest, This is an example of a method for interpolating moving images in this form.

[0217] An example of a moving image interpolation method in this embodiment is shown in FIG. The generated image is generated based on two adjacent input images. By displaying the video in the gap between the two, it is possible to interpolate the video. Preferably, the display period of the display image is half the input period of the input image. However, the display period is not limited to this, and various display periods can be used. For example, the display period can be set to the input period By setting it shorter than half, you can display the video more smoothly. By making it longer than half the period, power consumption can be reduced. The image is generated based on two adjacent input images, but the number of input images is limited to two. For example, three (or more than three) temporally adjacent If you generate an image based on an input image (good), it will be easier than if you generate an image based on two input images. It is possible to obtain a generated image with high accuracy. The same time as the input timing of 5122, that is, the display timing relative to the input timing Although it is delayed by one frame, the display timing in the video interpolation method of this embodiment is The timing is not limited to this, and various display timings can be used. For example, You can delay the display timing by one or more frames. Therefore, the timing of displaying the generated image 5123 can be delayed, so the image 5 This allows for ample time for the generation of 123, and reduces power consumption and manufacturing costs. If the display timing is too slow relative to the input timing, the input This increases the time period for storing the force image, and increases the memory capacity required for storage. The display timing relative to the input timing should preferably be delayed by 1 to 2 frames. I wish.

[0218] Here, the specific image 5123 generated based on the image 5121 and the image 5122 is In order to interpolate the moving image, the motion of the input image is detected. In this embodiment, a block map is used to detect the motion of the input image. However, there are various methods that can be used without being limited to this. (Methods such as taking the difference between image data and using Fourier transform) can be used. In the block matching method, first, the image data of one input image (here, the image 5121) into a data storage means (semiconductor memory, RAM, or other storage circuit, etc.) Then, the image in the next frame (image 5122 in this example) is stored in memory. The divided areas are rectangular with the same shape, as shown in Figure 20(A). It can be, but is not limited to, various things (shape or size depending on the image) Then, for each divided area, the data stored in the data storage means can be The data is compared with the image data of the previous frame (here, the image data of image 5121). In the example of FIG. 20(A), the image 5122 has a similar image data. A region similar in data to the region 5124 in the image 5121 is searched for, and the region 512 6 is searched. When searching within image 5121, the search range is limited. In the example of FIG. 20(A), the search range is set to area 5124. The area 5125 is set to be about four times the area of ​​the By increasing the size, it is possible to improve the detection accuracy even in fast-moving videos. However, if the search is too broad, the search time will be enormous, and the detection of movement will be difficult. Therefore, the area of ​​the region 5125 is set to be about two to six times the area of ​​the region 5124. Then, the searched region 5126 and the region in the image 5122 are compared. The difference in position between the area 5124 and the area 5125 is calculated as a motion vector 5127. 7 represents the movement of image data in the region 5124 during one frame period. To generate an image that represents the intermediate state of motion, the direction of the motion vector is kept the same but the size is changed. A modified image generation vector 5128 is created, and the vector 5128 is included in the region 5126 in the image 5121. The image data is moved according to the image generation vector 5128 to generate the image 5123. This series of processes is called image 512 By performing this for all regions in 2, image 5123 can be generated. Then, by sequentially displaying the input image 5121, the generated image 5123, and the input image 5122, 5121 and 5122. The position is different (i.e., moving) in the image 5123, but the generated image 512 3 is the midpoint of the object in the image 5121 and the image 5122. By displaying an image, the movement of the video can be made smoother, and blurred video caused by afterimages etc. can be prevented. The clarity can be improved.

[0219] The size of the image generation vector 5128 is determined according to the display timing of the image 5123. In the example of FIG. 20(A), the display timing of the image 5123 can be determined. is set to the midpoint (1 / 2) of the display timing of image 5121 and image 5122. The size of the image generation vector 5128 is half that of the motion vector 5127. For example, if the display timing is 1 / 3, the size is set to 1 / 3 and the display time is set to If the timing is 2 / 3, the size can be set to 2 / 3.

[0220] In this way, multiple regions with various motion vectors can be moved to create a new image. When creating an image, it is necessary to consider whether there are overlapping areas within the destination area where other areas have already been moved, or whether there are any overlapping areas within the destination area. There may be some blank areas that are not moved from the area. As a method for correcting the overlapping portion, for example, the overlapping data can be corrected by Priority is assigned based on the average method, the direction of the motion vector, etc., and high-priority data is generated. The method of using the data in the generated image, color (or brightness) is given priority, but brightness (or For example, the average of the number of pixels (or color) can be used. The image data at the corresponding position of the image 5121 or 5122 is directly used as the data in the generated image. The method of taking the average of the image data at the position of the image 5121 or the image 5122 Then, the generated image 5123 can be used as an image generation method. By displaying the timing according to the size of the vector 5128, the movement of the video becomes smoother. Furthermore, the problem of image retention caused by hold drive can be eliminated. You can improve the problem.

[0221] Another example of the moving image interpolation method in this embodiment is a time interpolation method as shown in FIG. A generated image generated based on two input images that are adjacent to each other is generated based on the two input images. When displaying the images in the gaps between the displayed images, each image is further divided into multiple sub-images. By dividing the image into multiple images and displaying them, it is possible to interpolate moving images. In addition to the benefits of shorter time, dark images are periodically displayed (the display method is This also provides the advantage of the image display period being closer to the image input period. This reduces blurring of the video due to afterimages, etc., compared to when the length is only half the power cycle. In the example of FIG. 20(B), the “input” and “generation” can be further improved. Since the same processing as in the example of 0(A) can be performed, the explanation will be omitted. In the example, "display" means dividing one input image and / or generated image into multiple sub-images. Specifically, as shown in FIG. 20(B), an image 5121 can be displayed as By dividing the image into sub-images 5121a and 5121b and displaying them sequentially, the image appears to the human eye as 5121 is perceived as being displayed, and image 5123 is perceived as being displayed as sub-images 5123a and 512 By dividing the image into 3b and displaying them sequentially, the human eye perceives it as if image 5123 is displayed. The image 5122 is divided into sub-images 5122a and 5122b and displayed sequentially. The human eye perceives the image 5122 as being displayed. The image to be perceived is the same as the example in FIG. 20(A), but the display method is impulse type. Since the image can be made closer to the original image, blurring of moving images due to afterimages and the like can be further improved. The number of divided sub-images is two in FIG. 20(B), but is not limited to this and may be various. The timing at which the sub-image is displayed is as shown in Figure 20 (B ) are set at equal intervals (1 / 2), but it is not limited to this and various display timings can be used. For example, the dark sub-images (5121b, 5122b, 5123b) By speeding up the display timing (specifically, from 1 / 4 to 1 / 2), the display Since the method can be made closer to the impulse type, blurring of moving images due to afterimages etc. can be reduced. Or, you can delay the timing of displaying the dark sub-image (specifically, 1 / 2 to 3 / 4 of the time), the period during which the bright image is displayed can be extended. , the display efficiency can be improved and the power consumption can be reduced.

[0222] Another example of the video interpolation method according to the present embodiment is to detect the shape of an object moving in an image. This is an example in which different processing is performed depending on the shape of the moving object. indicates the timing of display, similar to the example in Figure 20(B), but the displayed content is , and moving text (also called scrolling text, subtitles, tickers, etc.) Note that "input" and "generation" may be the same as in Figure 20(B). The blurring of moving images during hold driving is due to the nature of the moving object. This is especially noticeable when the characters are moving. This is because when reading moving text, your eyes inevitably follow the text, This is because hold blurring is likely to occur. Furthermore, characters should have clear outlines. This can further accentuate the blur caused by the hold blur. That is, it determines whether an object moving in the image is a character, and if so, performs further special processing. This is effective for reducing hold blur. Contour detection and / or pattern detection are performed on the object to determine whether the object is a character. If it is determined that there is a motion error, motion interpolation is performed even for sub-images divided from the same image. By displaying intermediate states of the movement, the movement can be made smoother. If it is determined that the character is not a character, it is divided into two parts from the same image, as shown in Figure 20(B). If the sub-image is a moving object, the position of the moving object can be displayed without changing. In the example shown in Figure 1, the area 5131 that is determined to be a character is moving upward. However, the position of the region 5131 is different between the image 5121a and the image 5121b. The same applies to images 5123a and 5123b, and images 5122a and 5122b. This allows for the blurring of moving characters, which is particularly noticeable, to be reduced to the normal motion blur. This makes the movement even smoother than with the double speed drive, so it can reduce the image lag and other problems that can occur with moving images. The blur can be further improved.

[0223] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0224] (Embodiment 9) In this embodiment, an example of a display device will be described.

[0225] First, an example of a system block of a liquid crystal display device will be described with reference to FIG. 21(A). The liquid crystal display device includes a circuit 5361, a circuit 5362, a circuit 5363_1, a circuit 5363_2, a circuit 5363_3, a circuit 5363_4, a circuit 5363_5, a circuit 5363_6, a circuit 5363_7, a circuit 5363_8, a circuit 5363_9, a circuit 5363_10, a circuit 5 2, a pixel portion 5364, a circuit 5365, and a lighting device 5366. In the figure, a plurality of wirings 5371 are arranged extending from a circuit 5362, and a plurality of wirings 5372 are arranged in a circuit. The wiring 5363_1 and the wiring 5363_2 are arranged to extend from each other. The intersections of the line 5371 and the wirings 5372 each have a display element such as a liquid crystal element. Pixels 5367 corresponding to the pixel area are arranged in a matrix.

[0226] The circuit 5361 is connected to the circuit 5362, the circuit 5363_1, the circuit 5364, the circuit 5365, and the circuit 5366 in response to the video signal 5360. 363_2 and the circuit 5365, and has a function of supplying a signal, a voltage, a current, or the like to the controller, control circuit, timing generator, power supply circuit, regulator, etc. In this embodiment, as an example, the circuit 5361 can function as a 362, a start signal for the signal line driver circuit (SSP), a clock signal for the signal line driver circuit ( SCK), inverted clock signal for signal line driver circuit (SCKB), data for video signal (DA TA), and a latch signal (LAT). Then, a start signal for the scanning line driving circuit (G SP), a clock signal for the scanning line driving circuit (GCK), and an inverted clock for the scanning line driving circuit Alternatively, the circuit 5361 may supply a signal (GCKB) to the circuit 5365. The circuit is intended to provide a backlight control signal (BLC), but is not limited to this. 5361 also transmits various other signals, various voltages, or various currents to a circuit 5362, a circuit The signal can be supplied to a circuit 5363_1, a circuit 5363_2, and a circuit 5365.

[0227] The circuit 5362 receives signals (e.g., SSP, SCK, SCKB) supplied from the circuit 5361. , DATA, LAT) to output video signals to multiple wirings 5371. The circuit 5363_1 and the circuit 536_2 can function as a signal line driver circuit. 3_2 runs in response to the signals (GSP, GCK, GCKB) supplied from the circuit 5361. It has a function of outputting scanning signals to a plurality of wirings 5372 and functions as a scanning line driver circuit. The circuit 5365 performs the following in response to the signal (BLC) supplied from the circuit 5361: By controlling the amount of power supplied to the lighting device 5366 or the time, the lighting device It has the function of controlling the brightness (or average brightness) of 5366 and can function as a power supply circuit. It is possible.

[0228] When video signals are input to the multiple wirings 5371, the multiple wirings 5371 The wirings 53 can function as lines, video signal lines, source lines, or the like. When a scanning signal is input to 72, the plurality of wirings 5372 are signal lines, scanning lines, or gate lines. It can function as a line, etc., but is not limited to this.

[0229] Note that the same signal is input from the circuit 5361 to the circuits 5363_1 and 5363_2. In this case, the circuit 5363_1 outputs scan signals to the wirings 5372 and the circuit 5363 The timing of the scanning signals output from the _2 to the multiple wirings 5372 is approximately the same. Therefore, the loads driven by the circuits 5363_1 and 5363_2 are reduced. Therefore, the display device can be made larger. Alternatively, the circuits 5363_1 and 5363_2 may have high resolution. Since the channel width of the transistor can be reduced, a display device with a narrow frame can be obtained. However, the present invention is not limited to this, and the circuit 5361 can be implemented by a circuit 5363_1 and a circuit 536 It is possible to supply separate signals to 3_2.

[0230] Note that one of the circuit 5363_1 and the circuit 5363_2 can be omitted.

[0231] In addition, in the pixel portion 5364, wiring such as a capacitance line, a power supply line, and a scanning line can be newly arranged. The circuit 5361 can output a signal or a voltage to these wirings. Alternatively, a circuit similar to the circuit 5363_1 or the circuit 5363_2 may be newly added. This newly added circuit outputs signals such as scanning signals to the newly added wiring. It is possible.

[0232] The pixel 5367 can have a light-emitting element such as an EL element as a display element. In this case, as shown in FIG. 21(B), the display element can emit light, so that the circuit 5 365 and the lighting device 5366 can be omitted. In order to supply power, a plurality of wirings 5373 that can function as power supply lines are provided in the pixel portion 53 64. The circuit 5361 distributes a power supply voltage called voltage (ANO). The wiring 5373 is connected to each color element of the pixel. It can be connected to all pixels in common.

[0233] Note that in FIG. 21B, as an example, the circuit 5361 includes a circuit 5363_1 and a circuit 536 3_2. The circuit 5361 is a circuit for a scanning line driver circuit. Start signal (GSP1), clock signal for scanning line driving circuit (GCK1), and scanning line driving The circuit 5363_1 is supplied with signals such as an inverted clock signal (GCKB1) for the operating circuit. The circuit 5361 outputs a start signal (GSP2) for the scanning line driving circuit, Clock signal (GCK2), inverted clock signal for scanning line driver circuit (GCKB2), etc. In this case, the circuit 5363_1 supplies the signal to the circuit 5363_2. 72, and the circuit 5363_2 scans only the odd-numbered wirings among the plurality of wirings 5372. That is, only the wirings in the even rows can be scanned. Since the driving frequency of the circuit 5363_2 can be reduced, power consumption can be reduced. Alternatively, the area in which one stage of flip-flops can be laid out can be increased. Therefore, the display device can be made high-definition. However, the present invention is not limited to this. As in FIG. 21A, the circuit 5361 can be The same signal can be output to the circuit 5363_1 and the circuit 5363_2.

[0234] 21B, the circuit 5361 in FIG. 21A is the same as the circuit 5363 in FIG. It is possible to provide separate signals to the circuit 5363_1 and the circuit 5363_2.

[0235] An example of the system block of the display device has been described above.

[0236] Next, an example of the configuration of the display device will be described with reference to FIGS. 22(A), (B), (C), (D), and ( Please refer to E) for further explanation.

[0237] In FIG. 22A, a circuit (for example, a circuit 5364) having a function of outputting a signal to the pixel portion 5364 is shown. 362, a circuit 5363_1, and a circuit 5363_2 are formed on the same substrate as the pixel portion 5364. The circuit 5361 is formed on a substrate different from the pixel portion 5364. This reduces the number of external components, thereby reducing costs. Since the number of signals or voltages input to the board 5380 is reduced, the board 5380 and the external components can be The number of connections can be reduced, which can improve reliability and yield. can.

[0238] When the circuit is formed on a substrate different from the pixel portion 5364, the substrate is a TAB (Ta Flexible PCB (Flexible Printed Circuit) Alternatively, the substrate may be , the pixel part 5364 is mounted on the same substrate 538 by the COG (Chip on Glass) method. It is possible to implement it in 0.

[0239] When the circuit is formed on a substrate different from the pixel portion 5364, the substrate is formed on a single crystal semiconductor. Therefore, it is possible to form a transistor using the substrate. The circuit has the advantages of improved drive frequency, improved drive voltage, and reduced output signal variation. You can get the points.

[0240] A signal, voltage, or current is input from an external circuit via an input terminal 5381. This is often the case.

[0241] In FIG. 22(B), circuits with low drive frequencies (for example, circuit 5363_1, circuit 5363_ 2) is formed on the same substrate 5380 as the pixel portion 5364. The circuit 5362 is formed on a substrate different from that of the pixel portion 5364. The transistors make it possible to configure circuits formed on the substrate 5380. Therefore, the semiconductor layer of the transistor may be made of a non-single-crystal semiconductor, a microcrystalline semiconductor, an organic semiconductor, or Therefore, it is possible to increase the size of the display device and reduce the number of manufacturing steps. This can reduce the number of parts, reduce costs, or improve yields.

[0242] As shown in FIG. 22C, a part of the circuit 5362 (circuit 5362a) is connected to the pixel section 53 The remaining circuit 5362 (circuit 5362b) is formed on the same substrate 5380 as the pixel section 564. The circuit 5362a can be formed on a different substrate from the circuit 364. Circuits that can be configured using transistors (e.g., shift registers, selectors, The circuit 5362b has high mobility and characteristic variations. A circuit (e.g., a shift register) that is preferably constructed using transistors with low They often have a built-in amplifier (e.g., a phase shifter, a latch circuit, a buffer circuit, a DA conversion circuit, an AD conversion circuit, etc.) By doing so, as in FIG. 22(B), a non-single layer can be used as the semiconductor layer of the transistor. A crystalline semiconductor, a microcrystalline semiconductor, an organic semiconductor, an oxide semiconductor, or the like can be used. This allows for further reduction in the number of external components.

[0243] In FIG. 22D, a circuit (for example, a circuit 5364) having a function of outputting a signal to the pixel portion 5364 is shown. 362, circuit 5363_1, and circuit 5363_2, etc.), and controlling these circuits A circuit having a function (for example, a circuit 5361) is formed on a substrate different from that of the pixel portion 5364. This makes it possible to form the pixel section and its peripheral circuits on separate substrates. Therefore, the yield can be improved.

[0244] As in FIG. 22(D), in FIGS. 22(A) to 22(C), the circuit 5363_1 and The circuit 5363_2 can be formed on a substrate different from that of the pixel portion 5364.

[0245] In FIG. 22(E), a part of the circuit 5361 (circuit 5361a) is on the same substrate as the pixel portion 5364. 5380, and the remaining circuit 5361 (circuit 5361b) is formed separately from the pixel portion 5364. The circuit 5361a is formed on a substrate. The circuit 5361a is formed by a transistor with low mobility. In some cases, the device has a circuit that can be switched (for example, a switch, a selector, a level shift circuit, etc.). The circuit 5361b uses transistors with high mobility and small variations in characteristics. A circuit (for example, a shift register, a timing generator) preferably configured using These often include a power supply, a resistor, an oscillator, a regulator, or an analog buffer.

[0246] 22(A) to 22(D), the circuit 5361a is mounted on the same substrate as the pixel section 5364. The circuit 5361b can be formed on a substrate different from that of the pixel portion 5364.

[0247] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0248] (Embodiment 10) In this embodiment, an example of a manufacturing process of a transistor and a capacitor will be described. A manufacturing process for the oxide semiconductor layer will be described. InMO3(ZnO) m It is possible to use layers expressed as (m>0). M is one or more metal elements selected from Ga, Fe, Ni, Mn and Co. There are metal elements. For example, M can be Ga, or Ga and Ni or G In some cases, the above metal elements other than Ga, such as Ga and Fe, may be contained. In addition to the metal elements contained as M, Fe, Ni and other transition metals are included as impurity elements. The thin film contains In-Ga elements or oxides of the transition metals. It can be shown as a Zn-O-based non-single crystal film. It is possible to use a mobile ion, typically sodium, in the oxide semiconductor layer. The concentration of 18 / cm 3 Below, and further 1×10 18 / cm 3 If it is below, This is preferable because it can prevent the electrical characteristics of the transistor from changing. The semiconductor layer is not limited to the above, and oxide semiconductors of various other materials can also be used. Alternatively, the semiconductor layer may be a single crystal semiconductor, a polycrystalline semiconductor, a microcrystalline (microcrystalline) semiconductor, or the like. (stal or nanocrystalline) semiconductors, amorphous semiconductors, or various non- A single crystal semiconductor or the like can be used.

[0249] 23A to 23C, an example of a manufacturing process of a transistor and a capacitor will be described. 23A to 23C show a transistor 5441 and a capacitor 5442. This is an example of a manufacturing process. The transistor 5441 is an example of an inverted staggered thin film transistor. a wiring is provided on the oxide semiconductor layer via a source electrode or a drain electrode; This is an example of a transistor.

[0250] First, a first conductive layer is formed on the entire surface of the substrate 5420 by sputtering. A resist mask formed by a photolithography process using a first photomask is used. Then, the first conductive layer is selectively etched to form a conductive layer 5421 and a conductive layer 5422. The conductive layer 5421 can function as a gate electrode, and the conductive layer 542 2 can function as one electrode of a capacitor element. The conductive layers 5421 and 5422 are used as wirings, gate electrodes, or electrodes of a capacitor. After this, the resist mask is removed.

[0251] Next, an insulating layer 5423 is formed on the entire surface by plasma CVD or sputtering. The insulating layer 5423 can function as a gate insulating layer, and the conductive layer 5421 The insulating layer 5423 is formed to cover the insulating layer 5424 and the conductive layer 5422. It is often between 100 and 250 nm.

[0252] When a silicon oxide layer is used as the insulating layer 5423, an organic silane gas is used. A silicon oxide layer can be formed by the CVD method. is ethyl silicate (TEOS: chemical formula Si(OC2H5)4), tetramethylsilane (TM S: Chemical formula Si(CH3)4), tetramethylcyclotetrasiloxane (TMCTS), Octamethylcyclotetrasiloxane (OMCTS), hexamethyldisilazane (HMD S), triethoxysilane (SiH(OC2H5)3), trisdimethylaminosilane ( Silicon-containing compounds such as SiH(N(CH3)2)3) or yttrium oxide (Y2 O3) can be used.

[0253] Next, a resist mask formed by a photolithography process using a second photomask 5423 to selectively etch the insulating layer 5423 to form a contact that reaches the conductive layer 5421. A hole 5424 is formed. After this, the resist mask is removed. However, the present invention is not limited to this. Therefore, the contact hole 5424 can be omitted. After forming the contact hole 5424, the contact hole 5424 can be formed. The cross-sectional view of this corresponds to FIG. 23(A).

[0254] Next, an oxide semiconductor layer is formed on the entire surface by sputtering. The oxide semiconductor layer is formed by sputtering, and then a n+ Forming a layer The thickness of the oxide semiconductor layer is preferably 5 nm to 200 nm. many.

[0255] Before forming the oxide semiconductor layer by a sputtering method, argon gas was introduced. It is preferable to perform reverse sputtering to generate plasma. This removes dust adhering to the surface of the insulating layer 5423 and the bottom of the contact hole 5424. Reverse sputtering is a method of removing aluminum without applying voltage to the target side. In a fluorine atmosphere, a voltage is applied to the substrate side using an RF power supply to form plasma on the substrate surface. However, the present invention is not limited to this, and the atmosphere may be changed to nitrogen or helium instead of argon. Alternatively, oxygen, N2O, etc. can be added to the argon atmosphere. Alternatively, Cl2, CF4, etc. can be added to the argon atmosphere. When reverse sputtering is performed, the insulating layer 5423 The surface is preferably removed by about 2 to 10 nm. After such plasma treatment, the surface is exposed to the atmosphere. By forming the oxide semiconductor layer without using any oxide film, the interface between the gate insulating layer and the semiconductor layer can be improved. It is useful in that it does not allow dust or moisture to adhere to it.

[0256] Next, the oxide semiconductor layer is selectively etched using a third photomask. Then, the resist mask is removed.

[0257] Next, a second conductive layer is formed on the entire surface by sputtering. The second conductive layer is selectively formed using a resist mask formed by a photolithography process. The conductive layer 5429, the conductive layer 5430, and the conductive layer 5431 are formed by etching the conductive layer 5429, the conductive layer 5430, and the conductive layer 5431. The conductive layer 5429 is connected to the conductive layer 5421 through a contact hole 5424. The conductive layer 5429 and the conductive layer 5430 function as a source electrode and a drain electrode. The conductive layer 5431 can function as the other electrode of the capacitor. However, the conductive layer 5429, the conductive layer 5430, and the conductive layer 54 31 is a part that functions as a wiring, a source or drain electrode, or an electrode of a capacitor element. It is possible to include

[0258] If a heat treatment (for example, at 200°C to 600°C) is to be carried out after this, the material must be able to withstand this heat treatment. It is preferable that the second conductive layer has heat resistance. Therefore, the second conductive layer is made of Al and Heat-resistant conductive materials (e.g., Ti, Ta, W, Mo, Cr, Nd, Sc, Zr, Ce, etc.) elements, alloys combining these elements, or nitrides containing these elements However, it is not limited to this, and the second conductive film By forming the second conductive film into a laminated structure, it is possible to provide the second conductive film with heat resistance. A heat-resistant conductive material such as Ti or Mo can be provided above and below the Al.

[0259] Before forming the second conductive layer by sputtering, argon gas was introduced to Reverse sputtering to generate a smear is performed, and the surface of the insulating layer 5423 and the surface of the oxide semiconductor layer are It is preferable to remove dust adhering to the surface and the bottom surface of the contact hole 5424. However, the present invention is not limited to this, and nitrogen, helium, etc. may be used instead of the argon atmosphere. Alternatively, the process can be carried out in an argon atmosphere to which oxygen, hydrogen, N2O, etc. have been added. Alternatively, it can be performed in an argon atmosphere with Cl2, CF4, etc. added. It is possible.

[0260] When etching the second conductive layer, a part of the oxide semiconductor layer is also etched. By this etching, an oxide semiconductor layer 5425 overlapping with the conductive layer 5421 is formed. the oxide semiconductor layer 5425 in a portion where the second conductive layer is not formed or the oxide semiconductor layer 5425 in a portion where the second conductive layer is not formed The oxide semiconductor layer 5425 is often thinned by being removed. Therefore, the oxide semiconductor layer may not be etched. Layer on + When a layer is formed, the oxide semiconductor layer is often etched. After this etching, the resist mask is removed. The cross section at this stage corresponds to FIG. 23(B). do.

[0261] Here, if reverse sputtering is performed before forming the second conductive layer by sputtering, The exposed portion of the insulating layer 5423 may be removed, preferably by about 2 to 10 nm. A recess may be formed in the edge layer 5423. Alternatively, the second conductive layer may be etched, After forming the conductive layer 5429, the conductive layer 5430, and the conductive layer 5431, reverse sputtering is performed. As a result, as shown in FIG. 23(B), a conductive layer 5429, a conductive layer 5430, and The end of the conductive layer 5431 may be curved.

[0262] Next, a heat treatment is performed at 200°C to 600°C in an air atmosphere or a nitrogen atmosphere. The treatment causes rearrangement at the atomic level in the In-Ga-Zn-O non-single crystal layer. The heat treatment (light annealing) here releases the distortion that inhibits carrier movement. The timing of this heat treatment is not limited, and the oxide semiconductor This can be done at various times after the body is formed.

[0263] Next, an insulating layer 5432 is formed over the entire surface. The insulating layer 5432 has a single-layer structure. For example, the insulating layer 5432 may be an organic thin film. When an insulating layer is used, a composition that is a material for the organic insulating layer is applied, and the applied composition is heated under an air atmosphere or nitrogen. Heat treatment is carried out at 200°C to 600°C in an atmosphere to form an organic insulating layer. By forming an organic insulating layer in contact with the oxide semiconductor layer, a thin film with high reliability in electrical properties can be obtained. A thin film transistor can be manufactured. Note that an organic insulating layer is used as the insulating layer 5432. In this case, a silicon nitride film or a silicon oxide film can be provided under the organic insulating layer.

[0264] In FIG. 23C, the insulating layer 5432 is formed using a non-photosensitive resin. For illustration, in the cross section of the region where the contact hole is to be formed, the end of the insulating layer 5432 is However, when the insulating layer 5432 is formed using a photosensitive resin, the contact In the cross section of the region where the cut hole is formed, the end of the insulating layer 5432 can be curved. As a result, the coverage of the third conductive layer or pixel electrode to be formed later is improved.

[0265] Instead of applying the composition, it may be applied by dipping, spraying, or ink depending on the material. Jet method, printing method, doctor knife, roll coater, curtain coater, knife coater It is possible to use a meter or the like.

[0266] Note that the composition of the material for the organic insulating layer was not subjected to heat treatment after the oxide semiconductor layer was formed. The heat treatment can also serve as heat treatment for the oxide semiconductor layer.

[0267] The insulating layer 5432 is formed to a thickness of 200 nm to 5 μm, preferably 300 nm to 1 μm. It is possible to do this.

[0268] Next, a third conductive layer is formed on the entire surface. Next, a photolithography process is performed using a fifth photomask. The third conductive layer is selectively etched using the resist mask formed by the etching process. A conductive layer 5433 and a conductive layer 5434 are formed. A cross-sectional view of the process up to this stage is shown in FIG. 23(C). The conductive layer 5433 and the conductive layer 5434 correspond to a wiring, a pixel electrode, a reflective electrode, a transparent electrode, and the like. In particular, the conductive layer 5434 can function as a transparent electrode or an electrode of a capacitor. Since the conductive layer 5422 is connected to the conductive layer 5422, it can function as an electrode of the capacitor 5442. However, it is not limited to this, and any other suitable material may be used that has the function of connecting the first conductive layer and the second conductive layer. For example, by connecting the conductive layer 5433 and the conductive layer 5434, The conductive layer 5422 and the conductive layer 5430 are connected to a third conductive layer (conductive layer 5433 and conductive layer 5434). ) can be connected.

[0269] Note that the capacitor 5442 is formed by the conductive layer 5422 and the conductive layer 5434. Since the structure is such that 1 is sandwiched, the capacitance value of the capacitor 5442 can be increased. However, the present invention is not limited to this, and one of the conductive layer 5422 and the conductive layer 5434 may be omitted. It is Noh.

[0270] After removing the resist mask by wet etching, the wafer is etched in air or nitrogen atmosphere. Heat treatment can be carried out at 200°C to 600°C in air.

[0271] Through the above steps, the transistor 5441 and the capacitor 5442 can be manufactured. .

[0272] As shown in FIG. 23D, an insulating layer 5435 is formed over the oxide semiconductor layer 5425. The insulating layer 5435 can be used to prevent oxidation when the second conductive layer is patterned. It has the function of preventing the nitride semiconductor layer from being eroded and functions as a channel stop film. Therefore, the thickness of the oxide semiconductor layer can be reduced, and the driving voltage of the transistor can be reduced. Reduction of the on-off current, improvement of the on-off ratio of the drain current, improvement of the S value, etc. Note that the insulating layer 5435 can be formed by successively forming an oxide semiconductor layer and an insulating layer over the entire surface. Then, a resist mask is formed by a photolithography process using a photomask. The insulating layer can be selectively patterned using a mask. After that, a second conductive layer is formed on the entire surface, and an oxide semiconductor layer is patterned simultaneously with the second conductive layer. That is, the oxide semiconductor layer and the second conductive layer are patterned using the same mask (reticle). In this case, an oxide semiconductor layer must be formed under the second conductive layer. In this way, the insulating layer 5435 is formed without increasing the number of steps. In such a manufacturing process, an oxide semiconductor layer is formed under the second conductive layer. However, the present invention is not limited to this, and the oxide semiconductor layer may be patterned. After that, an insulating layer is formed on the entire surface and patterned to form an insulating layer 54. 35 can be formed.

[0273] In FIG. 23D, the capacitor 5442 includes a conductive layer 5422 and a conductive layer 5431. The insulating layer 5423 and the oxide semiconductor layer 5436 are sandwiched between the insulating layer 5423 and the oxide semiconductor layer 5436. The oxide semiconductor layer 5436 can be omitted. 5431 is connected via a conductive layer 5437 formed by patterning the third conductive layer. Such a structure can be used, for example, in the pixels of a liquid crystal display device. For example, the transistor 5441 functions as a switching transistor and The element 5442 can function as a storage capacitor. The conductive layer 5422, the conductive layer 5429, and the conductive layer 5437 are gate lines, capacitance lines, and source lines, respectively. , can function as a pixel electrode. However, it is not limited to this. 23(D), the conductive layer 5430 and the conductive layer 5431 are connected to the third The connection can be made through a conductive layer.

[0274] As shown in FIG. 23(E), after the second conductive layer is patterned, the oxide semiconductor layer 5425. By doing so, the second conductive layer can be patterned. When the oxide semiconductor layer is removed, the oxide semiconductor layer is not formed. Therefore, the thickness of the oxide semiconductor layer can be reduced, and the driving Reduction of dynamic voltage, reduction of off-state current, improvement of on / off ratio of drain current, improvement of S value, etc. Note that the oxide semiconductor layer 5425 is formed by patterning the second conductive layer. After that, an oxide semiconductor layer is formed on the entire surface, and then photolithography is performed using a photomask. The oxide semiconductor layer is selectively patterned using a resist mask formed by a photolithography process. It can be formed by

[0275] In FIG. 23E, the capacitor element is formed by patterning the conductive layer 5422 and the third conductive layer. The insulating layer 5423 and the insulating layer 5432 are sandwiched between the insulating layer 5423 and the conductive layer 5439 formed by the insulating layer 5423 and the conductive layer 5439. The conductive layer 5422 and the conductive layer 5430 are formed by patterning the third conductive layer. The conductive layer 5439 is connected to the first conductive layer 5438 formed by the first conductive layer 5439. 23(E) is connected to the conductive layer 5440 formed by patterning the conductive layer 5440. 23(C) and (D), the conductive layer 5430 and the conductive layer 5422 are , can be connected via conductive layer 5438.

[0276] The thickness of the oxide semiconductor layer (or channel layer) is determined by the thickness of the depletion layer when the transistor is off. By making the thickness thinner than 1000 nm, it is possible to create a fully depleted state. In order to achieve this, the thickness of the oxide semiconductor layer is set to 2 It is preferably 0 nm or less, more preferably 10 nm or less, and even more preferably is preferably 6 nm or less.

[0277] In addition, the reduction of the transistor operating voltage, the reduction of the off-current, and the improvement of the on-off ratio of the drain current are also important. In order to improve the S value, the thickness of the oxide semiconductor layer is set to be equal to the thickness of the layers constituting the transistor. For example, the oxide semiconductor layer is preferably thinner than the insulating layer 5423. The thickness of the oxide semiconductor layer is preferably thinner than that of the insulating layer 5423. It is preferably 1 / 2 or less, and more preferably 1 / 5 or less. More preferably, it is 1 / 10 or less. However, it is not limited to this. In order to improve reliability, the oxide semiconductor layer may be thicker than the insulating layer 5423. In particular, when the oxide semiconductor layer is removed as shown in FIG. Since the thickness of the conductor layer is preferably thick, the thickness of the oxide semiconductor layer is set to be thicker than that of the insulating layer 5423. It is possible to make the thickness of the film thicker.

[0278] In order to increase the breakdown voltage of the transistor, the thickness of the insulating layer 5423 is set to be thicker than that of the first conductive layer. More preferably, the thickness of the insulating layer 5423 is 5 / 4 of that of the first conductive layer. It is preferable that the ratio is 4 / 3 or more. More preferably, it is 4 / 3 or more. However, the present invention is not limited to this, and the thickness of the insulating layer 5423 may be increased to increase the mobility of the transistor. can be thinner than the first conductive layer.

[0279] The substrate, insulating film, conductive film, and semiconductor layer of this embodiment may be the same as those of other embodiments. Materials described or similar to those described herein can be used.

[0280] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0281] (Embodiment 11) In this embodiment, examples of the structure of a transistor are shown in FIGS. ) will be referred to for explanation.

[0282] FIG. 24A shows an example of the structure of a top-gate transistor. This is an example of the structure of a bottom-gate transistor. 1 is an example of a structure of a transistor manufactured by

[0283] FIG. 24(A) shows a substrate 5260, an insulating layer 5261 formed on the substrate 5260, The insulating layer 5261 is formed on the insulating layer 5261, and includes a region 5262a, a region 5262b, a region 5262c, and a region A semiconductor layer 5262 having regions 5262d and 5262e, and a semiconductor layer 5262 having a thickness of 100 μm. The insulating layer 5263 is formed as shown in FIG. 5, and the insulating layer 5264 is formed on the semiconductor layer 5262 and the insulating layer 5263. a conductive layer 5264 formed over the insulating layer 5263 and the conductive layer 5264 and having an opening; an insulating layer 5265 formed on the insulating layer 5265 and in the opening of the insulating layer 5265; a layer 5266, a conductive layer 5267 formed on the conductive layer 5266 and on the insulating layer 5265, and having an opening; An insulating layer 5267 and a conductive layer formed on the insulating layer 5267 and in the opening of the insulating layer 5267 5268, and an insulating layer having an opening formed on the insulating layer 5267 and the conductive layer 5268. The insulating layer 5269 is formed on the insulating layer 5269 and in the opening of the insulating layer 5269. 270 and a conductive layer 5271 formed on the insulating layer 5269 and on the light-emitting layer 5270. show.

[0284] FIG. 24B shows a substrate 5300, a conductive layer 5301 formed on the substrate 5300, An insulating layer 5302 formed to cover the conductive layer 5301, and a conductive layer 5301 and an insulating layer 5302 A semiconductor layer 5303a formed on the semiconductor layer 302 and a semiconductor layer 5303b formed on the semiconductor layer 5303a A conductor layer 5303b and a conductive layer formed on the semiconductor layer 5303b and on the insulating layer 5302 a layer 5304, and a conductive layer 5305 formed on the insulating layer 5302 and the conductive layer 5304, the conductive layer 5305 having an opening. An insulating layer 5305 and a conductive layer formed on the insulating layer 5305 and in the opening of the insulating layer 5305 5306, and a liquid crystal layer 5307 disposed on the insulating layer 5305 and on the conductive layer 5306. 5308 formed on the liquid crystal layer 5307.

[0285] FIG. 24C shows a semiconductor substrate 5352 having a region 5353 and a region 5355, and a semiconductor An insulating layer 5356 formed on the semiconductor substrate 5352 and a an insulating layer 5354 formed on the insulating layer 5356; a conductive layer 5357 formed on the insulating layer 5356; 4. An insulating layer 535 having an opening formed on the insulating layer 5356 and the conductive layer 5357. 8 and a conductive layer 5359 formed on the insulating layer 5358 and in the opening of the insulating layer 5358. In this way, transistors are formed in each of the regions 5350 and 5351.

[0286] The insulating layer 5261 can function as a base film. The insulating layer 5263, the insulating layer 5302, and the insulating layer 5303 function as an isolation layer (for example, a field oxide film). The insulating layer 5356 can function as a gate insulating film. The insulating layer 5301 and the conductive layer 5357 can function as gate electrodes. The insulating layer 5265, the insulating layer 5267, the insulating layer 5305, and the insulating layer 5358 are interlayer films or flat films. The conductive layer 5266, the conductive layer 5304, and the conductive layer 5305 can function as a conductive film. 359 can function as a wiring, an electrode of a transistor, an electrode of a capacitor, or the like. The conductive layer 5268 and the conductive layer 5306 can be used as a pixel electrode, a reflective electrode, or the like. The insulating layer 5269 can function as a partition wall. The conductive layer 5271 and the conductive layer 5308 can function as a counter electrode, a common electrode, or the like. It is possible to do this.

[0287] Examples of the substrate 5260 and the substrate 5300 include a glass substrate, a quartz substrate, and a single crystal substrate ( For example, silicon substrates, SOI substrates, plastic substrates, metal substrates, stainless steel substrates, Substrate with stainless steel foil, tungsten substrate, tungsten foil Examples of glass substrates include barium borosilicate glass substrates. Examples of flexible substrates include glass and aluminoborosilicate glass. Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone Plastics such as polyethersulfone (PES) or flexible synthetic resins such as acrylic Other examples include laminated films (polypropylene, polyester, vinyl, poly vinyl fluoride, vinyl chloride, etc.), paper containing fibrous materials, base film (polyester , polyamide, polyimide, inorganic vapor deposition film, paper, etc.

[0288] The semiconductor substrate 5352 is, for example, a single-crystal Si substrate having n-type or p-type conductivity. However, it is not limited to this, and a plate similar to the substrate 5260 can be used. The region 5353 can be formed by, for example, introducing impurities into the semiconductor substrate 5352. For example, if the semiconductor substrate 5352 is a p-type conductive region, If the region 5353 has n-type conductivity, it functions as an n-well. On the other hand, when the semiconductor substrate 5352 has an n-type conductivity, the region 5353 has a p-type conductivity. The region 5355 has, for example, a region where impurities are not introduced into the semiconductor substrate 5 352 and functions as a source region or a drain region. The conductive substrate 5352 may have an LDD region formed therein.

[0289] Examples of the insulating layer 5261 include a silicon oxide (SiOx) film, a silicon nitride (SiNx) film, and an oxide film. Silicon nitride (SiOxNy)(x>y) film, silicon nitride oxide (SiNxOy)(x>y) film The insulating layer 5261 may be a film containing oxygen or nitrogen, such as a film containing oxygen or nitrogen, or a laminate structure of these. In one example of a two-layer structure, a silicon nitride film is provided as the first insulating layer, A silicon oxide film can be provided as the second insulating layer. The insulating layer 5261 has a three-layer structure. For example, a silicon oxide film is provided as the first insulating layer, and a silicon dioxide film is provided as the second insulating layer. It is possible to provide a silicon nitride film as an insulating layer and a silicon oxide film as a third insulating layer. do.

[0290] An example of the semiconductor layer 5262, the semiconductor layer 5303a, and the semiconductor layer 5303b is a non-single layer. Crystalline semiconductors (amorphous silicon, polycrystalline silicon, microcrystalline silicon, etc.) , single crystal semiconductor, compound semiconductor or oxide semiconductor (ZnO, InGaZnO, SiG e, GaAs, IZO, ITO, SnO, TiO, AlZnSnO(AZTO)), organic Examples include semiconductors and carbon nanotubes.

[0291] For example, the region 5262a is an intrinsic semiconductor layer 5262 to which no impurities are added. However, a small amount of impurity is added to the region 5262a. The impurity added to the region 5262a can be added to the region 5262b, 5262c, 5262d, or 5262e. The regions 5262b and 5262d are preferably lightly doped with impurities. This region functions as an LDD (Lightly Doped Drain) region. However, the area 5262b and the area 5262d can be omitted. The regions 5262c and 5262e are regions in which impurities are added to the semiconductor layer 5262 at high concentration. The region functions as a source region or a drain region.

[0292] The semiconductor layer 5303b is a semiconductor layer to which phosphorus or the like is added as an impurity element. It has n-type conductivity.

[0293] When an oxide semiconductor or a compound semiconductor is used for the semiconductor layer 5303a, The semiconductor layer 5303b can be omitted.

[0294] An example of the insulating layer 5263, the insulating layer 5302, and the insulating layer 5356 is silicon oxide (Si Ox) film, silicon nitride (SiNx) film, silicon oxynitride (SiOxNy)(x>y) film, nitride Films containing oxygen or nitrogen, such as silicon oxide (SiNxOy) (x>y) films, or There are also laminated structures.

[0295] Conductive layer 5264, conductive layer 5266, conductive layer 5268, conductive layer 5271, conductive layer 5301, A conductive layer 5304, a conductive layer 5306, a conductive layer 5308, a conductive layer 5357, and a conductive layer 535 Examples of the conductive film 9 include a single-layer conductive film and a laminated structure thereof. Examples include aluminum (Al), tantalum (Ta), titanium (Ti), and molybdenum. (Mo), tungsten (W), neodymium (Nd), chromium (Cr), nickel (Ni) , platinum (Pt), gold (Au), silver (Ag), copper (Cu), manganese (Mn), cobalt ( Co), niobium (Nb), silicon (Si), iron (Fe), palladium (Pd), carbon ( C), scandium (Sc), zinc (Zn), phosphorus (P), boron (B), arsenic (As) , Gallium (Ga), Indium (In), Tin (Sn), Oxygen (O), Zirconium (Z r), cerium (Ce), or Examples of such compounds include compounds containing one or more elements selected from the above group. In the case of the above, an alloy containing one or more elements selected from the above group (indium tin oxide (I TO), indium zinc oxide (IZO), indium tin oxide with silicon oxide (ITS O), zinc oxide (ZnO), tin oxide (SnO), cadmium tin oxide (CTO), aluminium Odim (Al-Nd), aluminum tungsten (Al-W), aluminum zirconium (Al- Zr), aluminum titanium (Al-Ti), aluminum cerium (Al-Ce), magnesium silver (Mg-Ag), Molybdenum Niobium (Mo-Nb), Molybdenum Tungsten (Mo-W ), molybdenum-tantalum (Mo-Ta) alloy materials, or one selected from the above group or compounds of nitrogen with multiple elements (such as titanium nitride, tantalum nitride, and molybdenum nitride) or a compound of one or more elements selected from the above group with silicon (e.g., titanium Titanium silicide, titanium silicide, nickel silicide, aluminum silicon, molybdenum Other examples include carbon nanotubes, organic nanotubes, and silicon silicide films. Nanotube materials include nanotubes, inorganic nanotubes, or metallic nanotubes.

[0296] Silicon (Si) is doped with n-type impurities (such as phosphorus) or p-type impurities (such as boron). The inclusion of impurities in silicon can improve conductivity and It is possible for it to behave in the same way as the human body, so it can be used as wiring or electrodes. It becomes easier to use.

[0297] Silicon can be found in single crystal, polycrystalline (polysilicon), microcrystalline (microcrystalline) Silicon with various crystallinity, such as amorphous silicon It is possible to use silicon that does not have crystallinity, such as single crystal silicon. By using crystalline silicon or polycrystalline silicon, wiring, electrodes, conductive layers, conductive films, The resistance of the silicon can be reduced. By using silicon, wiring and the like can be formed through simple processes.

[0298] When a semiconductor material such as silicon is used as the conductive layer, The material can be formed simultaneously with the semiconductor layer of the transistor.

[0299] Aluminum or silver has high conductivity and can reduce signal delay. Furthermore, aluminum or silver is easy to etch, making it easy to pattern and fine Fine processing can be performed.

[0300] Copper has high conductivity, which can reduce signal delay. When a laminated structure is used, it is preferable to use a laminated structure in order to improve adhesion.

[0301] Molybdenum or titanium is used in oxide semiconductors (ITO, IZO, etc.) or silicon It has the advantages of being less likely to cause defects even when in contact with the environment, being easy to etch, and having high heat resistance. Therefore, the conductive layer in contact with the oxide semiconductor or silicon is preferably Preferably, molybdenum or titanium is used.

[0302] Tungsten is desirable because it has advantages such as high heat resistance.

[0303] Neodymium is desirable because it has advantages such as high heat resistance. By using an alloy material of neodymium and aluminum, the aluminum does not form hillocks. However, it is not limited to this, and aluminum, tantalum, zirconia Aluminum can also be alloyed with aluminum, titanium, or cerium to In particular, alloy materials of aluminum and cerium are less likely to cause arcing. It can be significantly reduced.

[0304] In addition, ITO, IZO, ITSO, ZnO, Si, SnO, CTO, or carbon nanotubes Since the tubes and the like have light-transmitting properties, these materials can be used for the pixel electrode, the counter electrode, or the common electrode. It can be used for light-transmitting parts such as electrodes. In particular, IZO is suitable for etching. IZO is desirable because it is easy to etch and process. When IZO is etched, no residue remains. Therefore, when IZO is used as the pixel electrode, To reduce the occurrence of defects (short circuits, alignment disturbances, etc.) in liquid crystal elements and light-emitting elements can be done.

[0305] The conductive layer may have a single layer structure or a multilayer structure. The single-layer structure simplifies the manufacturing process for wiring, electrodes, conductive layers, conductive films, terminals, etc. This allows for the simplification of the manufacturing process, shortening the number of process days and reducing costs. By using a layered structure, the advantages of each material are utilized while reducing their disadvantages. For example, low resistance materials (aluminum, By incorporating a metal such as silicon into the multilayer structure, the resistance of the wiring can be reduced. For example, by sandwiching a low heat-resistant material between high heat-resistant materials in a laminated structure, This makes it possible to improve the heat resistance of wiring, electrodes, etc. while taking advantage of the advantages of heat-resistant materials. An example of such a laminated structure is a layer containing aluminum, a layer containing molybdenum, titanium, It is desirable to have a laminated structure in which the material is sandwiched between layers containing neodymium or the like.

[0306] In addition, when wiring, electrodes, etc. come into direct contact with each other, they may have a negative effect on each other. In this case, one wiring or electrode penetrates into the other wiring or electrode, changing the properties. As another example, if a high resistance part is formed, Or, problems may occur during production, making it impossible to produce normally. In this case, a material that changes its properties when it reacts with other materials is replaced with a material that does not react easily to those other materials. For example, ITO and aluminum can be sandwiched or covered by When connecting, titanium, molybdenum, neodymium alloy is used between ITO and aluminum. For example, when connecting silicon and aluminum, Titanium, molybdenum, and neodymium alloys can be sandwiched between silicon and aluminum. is. These materials are also used for wiring, electrodes, conductive layers, conductive films, terminals, vias, plugs, etc. It is possible to do this.

[0307] Insulating layer 5265, insulating layer 5267, insulating layer 5269, insulating layer 5305, and insulating layer 535 An example of the insulating layer 8 is a single-layer insulating layer or a laminated structure of these layers. Examples include a silicon oxide (SiOx) film, a silicon nitride (SiNx) film, or a silicon oxynitride film. Oxygen in silicon (SiOxNy)(x>y) film, silicon nitride oxide (SiNxOy)(x>y) film, etc. Or a film containing nitrogen, a film containing carbon such as a DLC (diamond-like carbon) film, or are siloxane resins, epoxy, polyimide, polyamide, polyvinylphenol, benzophenone, Examples of suitable materials include cyclobutene, and organic materials such as acrylic.

[0308] An example of the light-emitting layer 5270 is an organic EL element or an inorganic EL element. An example of the element is a hole injection layer made of a hole injection material, a hole transport layer made of a hole transport material, a light-emitting layer made of a light-emitting material; an electron transport layer made of an electron transport material; A single layer structure of an electron injection layer, or a layer in which a plurality of materials among these materials are mixed, or These include laminated structures.

[0309] Examples of the liquid crystal layer 5307 include nematic liquid crystal, cholesteric liquid crystal, and smectic liquid crystal. Crystals, discotic liquid crystals, thermotropic liquid crystals, lyotropic liquid crystals, low molecular weight liquid crystals, high Molecular liquid crystal, polymer dispersed liquid crystal (PDLC), ferroelectric liquid crystal, antiferroelectric liquid crystal, main chain liquid crystal, side Examples include chain-type polymer liquid crystals, plasma-addressed liquid crystals (PALC), and banana-shaped liquid crystals. The liquid crystal driving method is TN (Twisted Nematic) mode. mode, STN (Super Twisted Nematic) mode, IPS (In-P lane-Switching) mode, FFS (Fringe Field Switching) mode ching) mode, MVA(Multi-domain Vertical Alig) nment) mode, PVA(Patterned Vertical Alignme) nt) mode, ASV (Advanced Super View) mode, ASM (A xially Symmetric aligned Micro-cell) mode, OCB(Optically Compensated Birefringence) Mode, ECB (Electrically Controlled Birefringence ence) mode, FLC (Ferroelectric Liquid Crystal al) mode, AFLC (AntiFerroelectric Liquid Cry stal) mode, PDLC (Polymer Dispersed Liquid Crystal Crystal mode, guest host mode, Blue Phase mode etc.

[0310] Note that an insulating layer functioning as an alignment film is provided over the insulating layer 5305 and the conductive layer 5306. It is possible to form an insulating layer or the like that functions as a protrusion.

[0311] Note that a color filter, a black matrix, or a protrusion may be formed on the conductive layer 5308. An insulating layer or the like that functions as an alignment film can be formed under the conductive layer 5308. It is possible to form an insulating layer that acts as a barrier.

[0312] In the cross-sectional structure of FIG. 24(A), the insulating layer 5269, the light-emitting layer 5270, and the conductive layer 5271 is omitted, and the liquid crystal layer 5307 and the conductive layer 5308 shown in FIG. 24(B) are replaced with the insulating layer 526 7 and on conductive layer 5268.

[0313] In the cross-sectional structure of FIG. 24(B), the liquid crystal layer 5307 and the conductive layer 5308 are omitted. 24(A), the insulating layer 5269, the light-emitting layer 5270, and the conductive layer 5271 are formed on the insulating layer 530. 5 and on the conductive layer 5306.

[0314] In the cross-sectional structure of FIG. 24C, the insulating layer 5358 and the conductive layer 5359 are 24(A), an insulating layer 5269, a light-emitting layer 5270, and a conductive layer 5271 are formed. Alternatively, the liquid crystal layer 5307 and the conductive layer 5308 shown in FIG. 24(B) may be formed as an insulating layer. It can be formed on 5267 and on conductive layer 5268.

[0315] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate.

[0316] (Embodiment 12) In this embodiment, an example of an electronic device will be described.

[0317] 26(A) to 26(H) and 27(A) to 27(D) are diagrams showing electronic devices. These electronic devices include a housing 9630, a display unit 9631, a speaker 9633, an LED Lamp 9634, operation key 9635, connection terminal 9636, sensor 9637 (force, displacement, position Position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time , hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, smell or infrared rays The device may have a microphone 9638, etc.

[0318] FIG. 26(A) shows a mobile computer, which includes, in addition to the above, a switch 9670, It may have an infrared port 9671, etc. FIG. 26(B) shows a portable device equipped with a recording medium. A type of image reproducing device (for example, a DVD reproducing device), which, in addition to the above, also has a second display 26(C) shows a GOG In addition to the above, the display includes a second display unit 9632, a support unit 9673, 26(D) is a portable gaming machine, and In addition to the above, it may have a recording medium reading unit 9672, etc. It is a digital camera with a TV receiving function, and in addition to the above, it also has an antenna 9675, a shutter It may have a trigger button 9676, an image receiving unit 9677, etc. In addition to the above, it is a type gaming machine, and has a second display unit 9632, a recording medium reading unit 9672, FIG. 26(G) shows a television receiver, which, in addition to the above, can also have The portable television receiver can have a monitor, an image processor, etc. In addition to the above, it may have a charger 9678 capable of transmitting and receiving signals, etc. FIG. 27(A) shows a display, which includes, in addition to the above, a support base 9679, etc. FIG. 27(B) shows a camera, which, in addition to the above, can have an external connection port. It may have a port 9680, a shutter button 9676, an image receiving unit 9677, etc. FIG. 27(C) shows a computer, which, in addition to the above, has a pointing device 96 81, an external connection port 9680, a reader / writer 9682, etc. 27(D) is a mobile phone, and in addition to the above, it includes a transmitting unit, a receiving unit, a mobile phone / mobile A tuner for one segment partial reception service for a terminal, etc.

[0319] The electronic devices shown in FIGS. 26(A) to 26(H) and 27(A) to 27(D) are various For example, various information (still images, videos, text images, etc.) Function to display on the display, touch panel function, calendar, date or time, etc. Functions, functions to control processing by various software (programs), wireless communication functions, The ability to connect to various computer networks using wireless communication functions, The function of transmitting or receiving various data using the program or The data can be read out and displayed on the display unit. In electronic devices with displays, one display is used primarily to display image information, and another is used A function that mainly displays text information on one display unit, or a function that takes parallax into account on multiple displays By displaying an image, it is possible to have a function of displaying a three-dimensional image. In electronic devices with an image receiving unit, there are functions for taking still images, taking videos, and The function to automatically or manually correct the captured image, and to save the captured image to a recording medium (external or camera). It can have functions such as saving the captured image to a built-in memory, displaying the captured image on the display, etc. Note that the electronic devices shown in FIGS. 26(A) to 26(H) and 27(A) to 27(D) The functions that can be possessed by the are not limited to these, and the function can have various functions.

[0320] The electronic device described in this embodiment has a display unit for displaying some information. The electronic device is characterized in that the influence of variations in transistor characteristics is minimized in the display section. This reduces the image distortion, allowing for a very uniform image to be displayed.

[0321] Next, application examples of the semiconductor device will be described.

[0322] FIG. 27(E) shows an example in which a semiconductor device is integrated with a building. ) includes a housing 9730, a display unit 9731, a remote control device 9732 which is an operation unit, and a speaker 9 733, etc. The semiconductor device is a wall-mounted type that is integrated with the building, and the installation space is It can be installed without requiring a large space.

[0323] FIG. 27(F) shows another example in which a semiconductor device is provided inside a building as an integral part of the building. The display panel 9741 is attached to the unit bath 9742 as a unit. The display panel 9741 can be viewed.

[0324] In this embodiment, a wall and a unit bath are used as examples of buildings. The manner in which the semiconductor device is installed is not limited to this, and the semiconductor device can be installed in various buildings.

[0325] Next, an example in which the semiconductor device is integrated with a moving object will be described.

[0326] 27G is a diagram showing an example in which the semiconductor device is provided in an automobile. 9761 is attached to the body of a vehicle 9762 and is used to prevent the movement of the body or the movement from inside or outside the body. The information entered can be displayed on demand. It may be possible.

[0327] FIG. 27(H) is a diagram showing an example in which a semiconductor device is integrated with a passenger airplane. FIG. 27(H) shows a passenger airplane with a display panel 9782 on the ceiling 9781 above the seats. The display panel 9782 is attached to the ceiling 97. 81 and the hinge part 9783 are attached together, and the extension and contraction of the hinge part 9783 This allows passengers to view the display panel 9782. The display panel 9782 is operated by passengers. It has the function of displaying information by

[0328] In this embodiment, the moving body is exemplified by an automobile body and an airplane body. However, this is not limited to motorcycles, four-wheeled vehicles (including cars, buses, etc.), trains (monorails, etc.), It can be installed on a variety of things, including buildings, railways, ships, etc.

[0329] In this embodiment, the contents described in each drawing may be the same as those described in another embodiment. However, they can be freely combined or replaced as appropriate. [Explanation of symbols]

[0330] 101 Transistor 102 Capacitor element 103 Wiring 104 Wiring 105 Display element 106 Wiring 107 Circuit Elements 108 Wiring 201 Switch 202 Switch 203 Switch 204 Switch 205 Switch 206 Wiring 207 Switch 208 Wiring 301 Switch 303 Switch 305 Switch 306 Wiring 307 Switch 308 Wiring 401 Switch 403 Switch 405 Switch 406 Wiring 407 Switch 408 Wiring 501 Switch 503 Switch 505 Switch 506 Wiring 507 Switch 508 Wiring 601 Switch 603 Switch 605 Switch 606 Wiring 607 Switch 608 Wiring 101A transistor 101B transistor 101M transistor 102A Capacitive Element 102B Capacitive element 102M capacitance element 103M Wiring 104M wiring 105M light emitting element 106M wiring 106N Wiring 106P wiring 106Q wiring 201M transistor 202M transistor 203M transistor 204M transistor 9630 chassis 9631 Display section 9632 Display section 9633 Speaker 9634 LED Lamp 9635 Operation Key 9636 Connection terminal 9637 Sensor 9638 Microphone 9670 Switch 9671 Infrared port 9672 Recording medium reading unit 9673 Support part 9674 Earphones 9675 Antenna 9676 Shutter button 9677 Image receiving unit 9678 charger 9679 Support stand 9680 External connection port 9681 Pointing Device 9682 Reader / Writer 9730 chassis 9731 Display section 9732 Remote control device 9733 Speaker 9741 Display Panel 9742 Unit bath 9761 Display Panel 9762 Body 9781 Ceiling 9782 Display Panel 9783 Hinge part 1200M pixels 1200N pixels 1200P pixels 1200Q pixels 1201M wiring 1202M wiring 1203M Wiring 1204M wiring 5121 images 5122 images 5123 images 5124 area 5125 area 5126 area 5127 Vector 5128 Image Generation Vectors 5129 area 5130 Object 5131 area 5260 board 5261 Insulation layer 5262 Semiconductor layer 5263 Insulation layer 5264 Conductive layer 5265 Insulation layer 5266 Conductive layer 5267 Insulation layer 5268 Conductive layer 5269 Insulation layer 5270 luminous layer 5271 Conductive layer 5300 board 5301 Conductive layer 5302 Insulation layer 5304 Conductive layer 5305 Insulation layer 5306 Conductive layer 5307 Liquid crystal layer 5308 Conductive layer 5350 area 5351 area 5352 Semiconductor substrate 5353 area 5354 Insulation layer 5355 area 5356 Insulation layer 5357 Conductive layer 5358 Insulation layer 5359 Conductive layer 5360 video signal 5361 Circuit 5362 Circuit 5363 Circuit 5364 Pixel section 5365 Circuit 5366 Lighting equipment 5367 pixels 5371 Wiring 5372 Wiring 5373 Wiring 5380 PCB 5381 input terminal 5420 PCB 5421 Conductive layer 5422 Conductive layer 5423 Insulation layer 5424 Contact Hole 5425 Oxide semiconductor layer 5429 Conductive layer 5430 Conductive layer 5431 Conductive layer 5432 Insulation layer 5433 Conductive layer 5434 Conductive layer 5435 Insulation layer 5436 Oxide semiconductor layer 5437 Conductive layer 5438 Conductive layer 5439 Conductive layer 5440 Conductive layer 5441 Transistor 5442 Capacitor element 5121a Image 5121b Image 5122a Image 5122b image 5123a Image 5123b Image 5262a area 5262b area 5262c area 5262d area 5262e area 5303a Semiconductor layer 5303b Semiconductor layer 5361a circuit 5361b circuit 5362a circuit 5362b circuit 2501 Capacitor 2502 Capacitor

Claims

1. A display device including a pixel including first to fifth transistors, a light-emitting element, a first wiring, a second wiring, a third wiring, a fourth wiring, and a fifth wiring, the first transistor has a function of controlling a value of a current supplied to the light-emitting element in accordance with a potential of a video signal; the second transistor has a function of supplying a potential of the video signal input to the pixel via the first wiring to a gate of the first transistor; one of the source and the drain of the third transistor is always electrically connected to the gate of the first transistor; the other of the source and the drain of the third transistor is always electrically connected to the one of the source and the drain of the first transistor; one of the source and the drain of the fourth transistor is always electrically connected to the second wiring; the other of the source and the drain of the fourth transistor is always electrically connected to the one of the source and the drain of the first transistor; one of the source and the drain of the fifth transistor is always electrically connected to the other of the source and the drain of the first transistor; the other of the source and the drain of the fifth transistor is always electrically connected to a pixel electrode of the light-emitting element, the third transistor has a channel region in an oxide semiconductor layer; the gate of the third transistor is always electrically connected to the third wiring; the gate of the fourth transistor is always electrically connected to the fourth wiring; the gate of the fifth transistor is always electrically connected to the fifth wiring; a period in which the third transistor is in an on state, the fourth transistor is in an on state, and the fifth transistor is in an off state, before the period in which the video signal is input to the pixel; Display device.

2. A display device including a pixel including first to fifth transistors, a light-emitting element, a first wiring, a second wiring, a third wiring, a fourth wiring, a fifth wiring, and a capacitor, the first transistor has a function of controlling a value of a current supplied to the light-emitting element in accordance with a potential of a video signal; the second transistor has a function of supplying a potential of the video signal input to the pixel via the first wiring to a gate of the first transistor; one of the source and the drain of the third transistor is always electrically connected to the gate of the first transistor; the other of the source and the drain of the third transistor is always electrically connected to the one of the source and the drain of the first transistor; one of the source and the drain of the fourth transistor is always electrically connected to the second wiring; the other of the source and the drain of the fourth transistor is always electrically connected to the one of the source and the drain of the first transistor; one of the source and the drain of the fifth transistor is always electrically connected to the other of the source and the drain of the first transistor; the other of the source and the drain of the fifth transistor is always electrically connected to a pixel electrode of the light-emitting element, one of the electrodes of the capacitance element is always electrically connected to the gate of the first transistor; the third transistor has a channel region in an oxide semiconductor layer; the gate of the third transistor is always electrically connected to the third wiring; the gate of the fourth transistor is always electrically connected to the fourth wiring; the gate of the fifth transistor is always electrically connected to the fifth wiring; a period in which the third transistor is in an on state, the fourth transistor is in an on state, and the fifth transistor is in an off state, before the period in which the video signal is input to the pixel; Display device.

3. A display device including a pixel including first to fifth transistors, a light-emitting element, a first wiring, a second wiring, a third wiring, a fourth wiring, and a fifth wiring, the first transistor has a function of controlling a value of a current flowing from the second wiring to the light-emitting element in accordance with a potential of a video signal; the second transistor has a function of supplying a potential of the video signal input to the pixel via the first wiring to a gate of the first transistor; one of the source and the drain of the third transistor is always electrically connected to the gate of the first transistor; the other of the source and the drain of the third transistor is always electrically connected to the one of the source and the drain of the first transistor; one of the source and the drain of the fourth transistor is always electrically connected to the second wiring; the other of the source and the drain of the fourth transistor is always electrically connected to the one of the source and the drain of the first transistor; one of the source and the drain of the fifth transistor is always electrically connected to the other of the source and the drain of the first transistor; the other of the source and the drain of the fifth transistor is always electrically connected to a pixel electrode of the light-emitting element, the third transistor has a channel region in an oxide semiconductor layer; the gate of the third transistor is always electrically connected to the third wiring; the gate of the fourth transistor is always electrically connected to the fourth wiring; the gate of the fifth transistor is always electrically connected to the fifth wiring; a period in which the third transistor is in an on state, the fourth transistor is in an on state, and the fifth transistor is in an off state, before the period in which the video signal is input to the pixel; Display device.

4. A display device including a pixel including first to fifth transistors, a light-emitting element, a first wiring, a second wiring, a third wiring, a fourth wiring, a fifth wiring, and a capacitor, the first transistor has a function of controlling a value of a current flowing from the second wiring to the light-emitting element in accordance with a potential of a video signal; the second transistor has a function of supplying a potential of the video signal input to the pixel via the first wiring to a gate of the first transistor; one of the source and the drain of the third transistor is always electrically connected to the gate of the first transistor; the other of the source and the drain of the third transistor is always electrically connected to the one of the source and the drain of the first transistor; one of the source and the drain of the fourth transistor is always electrically connected to the second wiring; the other of the source and the drain of the fourth transistor is always electrically connected to the one of the source and the drain of the first transistor; one of the source and the drain of the fifth transistor is always electrically connected to the other of the source and the drain of the first transistor; the other of the source and the drain of the fifth transistor is always electrically connected to a pixel electrode of the light-emitting element, one of the electrodes of the capacitance element is always electrically connected to the gate of the first transistor; the third transistor has a channel region in an oxide semiconductor layer; the gate of the third transistor is always electrically connected to the third wiring; the gate of the fourth transistor is always electrically connected to the fourth wiring; the gate of the fifth transistor is always electrically connected to the fifth wiring; a period in which the third transistor is in an on state, the fourth transistor is in an on state, and the fifth transistor is in an off state, before the period in which the video signal is input to the pixel; Display device.

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