JP2018072462A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of displaying an image at an optimum luminance independent from the use environment, and to provide a display device suitable for high definition.SOLUTION: The display device has a first electrode and a second electrode arranged along a first direction, and a third electrode and a fourth electrode disposed on a plane different from the first electrode and arranged in a second direction intersecting the first direction. The first electrode and the second electrode each function as one electrode of a liquid crystal element; and the third electrode and the fourth electrode each function as one electrode of a light-emitting element. The first electrode and the second electrode are configured to have a notch in a portion overlapping either the third electrode or the fourth electrode.SELECTED DRAWING: Figure 1

Description

  One embodiment of the present invention relates to a display device and a manufacturing method thereof.

  Note that one embodiment of the present invention is not limited to the above technical field. Technical fields of one embodiment of the present invention disclosed in this specification and the like include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, and driving methods thereof , Or a method for producing them, can be mentioned as an example.

  Note that in this specification and the like, a semiconductor device refers to any device that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, a memory device, or the like is one embodiment of a semiconductor device. In addition, an imaging device, an electro-optical device, a power generation device (including a thin film solar cell, an organic thin film solar cell, and the like) and an electronic device may include a semiconductor device.

  A display device to which an organic EL (Electro Luminescence) element or a liquid crystal element is applied is known. In addition, a light-emitting device including a light-emitting element such as a light-emitting diode (LED), electronic paper that performs display by an electrophoresis method, and the like can be given as examples of the display device.

  The basic structure of the organic EL element is such that a layer containing a light-emitting organic compound is sandwiched between a pair of electrodes. Light emission can be obtained from the light-emitting organic compound by applying a voltage to this element. A display device to which such an organic EL element is applied can realize a thin, lightweight, high-contrast display device with low power consumption.

  Active matrix liquid crystal display devices are roughly classified into two types, a transmission type and a reflection type.

  The transmissive liquid crystal display device uses a backlight such as a cold cathode fluorescent lamp or an LED (Light Emitting Diode), and the light from the backlight transmits the liquid crystal by utilizing the optical modulation action of the liquid crystal. A state that is output to the outside and a state that is not output are selected, bright and dark display is performed, and further, they are combined to perform image display.

  In addition, the reflective liquid crystal display device utilizes the optical modulation action of the liquid crystal, and the external light, that is, the incident light is reflected by the pixel electrode and output to the outside of the device, and the incident light is not output to the outside of the device. An image is displayed by selecting a state, displaying bright and dark, and combining them. The reflective liquid crystal display device has an advantage of low power consumption because it does not use a backlight as compared with the transmissive liquid crystal display device.

  For example, an active matrix liquid crystal display device using a transistor having a metal oxide channel formation region as a switching element connected to each pixel electrode is known (Patent Document 1 and Patent Document 2).

JP 2007-123861 A JP 2007-96055 A

  In an electronic device to which a display device is applied, it is required to display an image with an optimum luminance according to a use environment. In particular, in a device that uses a battery as a power source, such as a mobile phone, a smartphone, a tablet terminal, a smart watch, and a notebook personal computer, the usage environment often changes unlike a stationary device. In particular, in a place where the outside light is bright, it is required to display high luminance with low power consumption.

  An object of one embodiment of the present invention is to provide a display device that can display with optimal luminance regardless of an environment of use. Another object is to improve display quality of a display device. Another object is to display an image with high display quality regardless of the use environment.

  An object of one embodiment of the present invention is to provide a display device suitable for high definition and a manufacturing method thereof. Another object is to provide a display device that can be driven with low power consumption. Another object is to provide a thin display device. Another object is to provide a lightweight display device. Another object is to provide a display device that can be bent.

  Note that the description of these problems does not disturb the existence of other problems. Note that one embodiment of the present invention does not have to solve all of these problems. Issues other than these can be extracted from the description, drawings, claims, and the like.

  According to one embodiment of the present invention, a first electrode and a second electrode arranged side by side in a first direction and a second direction intersecting the first direction on a surface different from the first electrode The display device includes a third electrode and a fourth electrode which are provided side by side. The first electrode and the second electrode each function as one electrode of the liquid crystal element. The third electrode and the fourth electrode each function as one electrode of the light emitting element. In addition, the first electrode and the second electrode have a notch in a portion overlapping with either the third electrode or the fourth electrode.

  Another embodiment of the present invention is a display device including first to fourth electrodes. The first electrode and the second electrode each have a function of reflecting visible light, and each function as one electrode of a liquid crystal element. The third electrode and the fourth electrode each function as one electrode of the light emitting element. The first electrode and the second electrode each have a strip shape extending in the first direction, and are arranged side by side in a second direction intersecting the first direction. The third electrode and the fourth electrode are arranged side by side in the first direction. The first electrode has a first notch at a position overlapping with the third electrode, and the second electrode has a second notch at a position overlapping with the fourth electrode.

  Moreover, in the above, it is preferable to have a 1st colored layer and a 2nd colored layer. At this time, it is preferable that the first colored layer and the second colored layer each have a strip shape extending in the first direction and are arranged side by side in the second direction. The first colored layer preferably has a portion overlapping with the first electrode, and the second colored layer preferably has a portion overlapping with the second electrode.

  In the above, the first colored layer has a third notch at a position overlapping with the third electrode, and the second colored layer is positioned at a position overlapping with the fourth electrode. It is preferable to have a notch. At this time, the light-emitting element having the third electrode and the light-emitting element having the fourth electrode preferably emit light having different colors.

  Alternatively, in the above, the first colored layer has a portion overlapping with the first notch and the third electrode, and the second colored layer overlaps with the second notch and the fourth electrode. It is preferable to have a portion. At this time, the light-emitting element having the third electrode and the light-emitting element having the fourth electrode preferably emit light having the same color.

  In the above, it is preferable to include first to sixth wirings. At this time, the first wiring and the second wiring each function as a first scanning line for driving the liquid crystal element, and the third wiring functions as a first signal line for driving the liquid crystal element. The fourth wiring functions as a second scanning line for driving the light-emitting element, and the fifth wiring and the sixth wiring function as a second signal line for driving the light-emitting element, respectively. In addition, the first wiring, the second wiring, and the fourth wiring each extend in the first direction, and the third wiring, the fifth wiring, and the sixth wiring each include the second wiring. It is preferable to extend in the direction.

  In the above, it is preferable that the first to sixth wirings and the first to sixth transistors be included. At this time, for example, the first wiring, the second wiring, and the fourth wiring each extend in the first direction, and the third wiring, the fifth wiring, and the sixth wiring are respectively Extends in the second direction. The first transistor is electrically connected to the first electrode, the second transistor is electrically connected to the second electrode, and the third transistor is connected to the first transistor through the fourth transistor. The fifth transistor is electrically connected to the fourth electrode through the sixth transistor. The first wiring is electrically connected to the gate of the first transistor. The second wiring is electrically connected to the gate of the second transistor. The third wiring is electrically connected to one of a source and a drain of the first transistor and one of a source and a drain of the second transistor. The fourth wiring is electrically connected to the gate of the third transistor and the gate of the fifth transistor. The fifth wiring is electrically connected to one of a source and a drain of the third transistor. The sixth wiring is electrically connected to one of a source and a drain of the fifth transistor.

  According to one embodiment of the present invention, it is possible to provide a display device that can display with optimal luminance regardless of the use environment. Further, the display quality of the display device can be improved. Alternatively, the video can be displayed with high display quality regardless of the use environment.

  One embodiment of the present invention can provide a display device suitable for high definition and a manufacturing method thereof. Alternatively, a display device that can be driven with low power consumption can be provided. Alternatively, a display device with a small thickness can be provided. Alternatively, a lightweight display device can be provided. Alternatively, a display device that can be bent can be provided.

  Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these can be extracted from the description, drawings, claims, and the like.

2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 2 shows a configuration example of a display device. 8A and 8B illustrate an example of a method for manufacturing a display device. 8A and 8B illustrate an example of a method for manufacturing a display device. 8A and 8B illustrate an example of a method for manufacturing a display device. 8A and 8B illustrate an example of a method for manufacturing a display device. 8A and 8B illustrate an example of a method for manufacturing a display device. 2 shows a configuration example of a display device. The schematic diagram and state transition diagram of a display apparatus. A circuit diagram and a timing chart. Configuration example of an electronic device. Configuration example of an electronic device.

  Embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

  Note that in structures of the invention described below, the same portions or portions having similar functions are denoted by the same reference numerals in different drawings, and description thereof is not repeated. In addition, in the case where the same function is indicated, the hatch pattern is the same, and there is a case where no reference numeral is given.

  Note that in each drawing described in this specification, the size, the layer thickness, or the region of each component is exaggerated for simplicity in some cases. Therefore, it is not necessarily limited to the scale.

  In the present specification and the like, ordinal numbers such as “first” and “second” are used for avoiding confusion between components, and are not limited numerically.

  A transistor is a kind of semiconductor element, and can realize amplification of current and voltage, switching operation for controlling conduction or non-conduction, and the like. The transistor in this specification includes an IGFET (Insulated Gate Field Effect Transistor) and a thin film transistor (TFT: Thin Film Transistor).

  In the following, expressions indicating the direction such as “up” and “down” are basically used in combination with the direction of the drawing. However, for the purpose of facilitating the description and the like, the direction indicated by “upper” or “lower” in the specification may not match the drawing. As an example, when explaining the stacking order (or forming order) of a laminated body or the like, the surface (formation surface, support surface, adhesive surface, flat surface, etc.) on the side where the laminated body is provided in the drawing Even if it is positioned above the laminated body, the direction may be expressed as “down”, the opposite direction may be expressed as “up”, and the like.

  Note that in this specification, an EL layer refers to a layer including at least a light-emitting substance (also referred to as a light-emitting layer) or a stacked body including a light-emitting layer, which is provided between a pair of electrodes of a light-emitting element.

  In this specification and the like, a display panel which is one embodiment of a display device has a function of displaying (outputting) an image or the like on a display surface. Therefore, the display panel is one mode of the output device.

  Further, in this specification and the like, a display panel substrate, for example, a connector such as a FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package) is attached, or the substrate is integrated with a COG (Chip On Glass) method or the like. In some cases, is mounted a display panel module, a display module, or simply a display panel.

  In this specification and the like, the touch sensor has a function of detecting that a detection target such as a finger or a stylus touches, presses, or approaches. Moreover, you may have the function to detect the positional information. Therefore, the touch sensor is an aspect of the input device. For example, the touch sensor can be configured to have one or more sensor elements.

  In this specification and the like, a substrate having a touch sensor may be referred to as a touch sensor panel or simply a touch sensor. In addition, in this specification and the like, a touch sensor panel substrate, for example, a connector such as an FPC or TCP attached, or a substrate in which an IC is mounted by a COG method, a touch sensor panel module, a touch sensor It may be called a module, a sensor module, or simply a touch sensor.

  Note that in this specification and the like, a touch panel which is one embodiment of a display device has a function of displaying (outputting) an image or the like on a display surface, and a detection target such as a finger or a stylus touches, presses, or approaches the display surface. And a function as a touch sensor for detecting the above. Accordingly, the touch panel is an embodiment of an input / output device.

  The touch panel can also be referred to as, for example, a display panel with a touch sensor (or display device) or a display panel with a touch sensor function (or display device).

  The touch panel can be configured to include a display panel and a touch sensor panel. Alternatively, the display panel may have a function as a touch sensor inside or on the surface.

  In this specification and the like, a touch panel substrate having a connector such as an FPC or TCP attached, or a substrate having an IC mounted on the substrate by a COG method, a touch panel module, a display module, or simply a touch panel And so on.

(Embodiment 1)
In this embodiment, structural examples of the display device of one embodiment of the present invention will be described.

  The display element of one embodiment of the present invention is a display device in which a first display element that reflects visible light and a second display element that emits visible light are mixed.

  The display device has a function of displaying an image with one or both of first light reflected by the first display element and second light emitted by the second display element. Alternatively, the display device functions to express gradation by controlling the amount of first light reflected by the first display element and the amount of second light emitted by the second display element, respectively. Have

  In addition, the display device controls the first pixel that expresses gradation by controlling the amount of reflected light from the first display element, and the gradation by controlling the amount of light emitted from the second display element. A structure including the second pixel to be expressed is preferable. A plurality of first pixels and second pixels are arranged in a matrix, for example, and constitute a display unit.

  In addition, it is preferable that the first pixels and the second pixels are arranged in the display area with the same number and the same pitch. At this time, the adjacent first pixel and second pixel can be collectively referred to as a pixel unit.

  Furthermore, it is preferable that the first pixel and the second pixel are arranged in a mixed manner in the display region of the display device. More specifically, the first pixel and the second pixel are preferably stacked and arranged in the display area. Thereby, as will be described later, both the image displayed only with the plurality of first pixels, the image displayed only with the plurality of second pixels, and the plurality of first pixels and the plurality of second pixels. Each of the images displayed in can be displayed in the same display area.

  As the first display element included in the first pixel, an element that reflects external light for display can be used. Since such an element does not have a light source, power consumption during display can be extremely reduced.

  As the first display element, a reflective liquid crystal element can be typically used. Alternatively, as the first display element, in addition to a shutter-type MEMS (Micro Electro Mechanical Systems) element, an optical interference-type MEMS element, a microcapsule method, an electrophoresis method, an electrowetting method, an electronic powder fluid (registered trademark) An element to which a method or the like is applied can be used.

  In addition, the second display element included in the second pixel includes a light source, and an element that performs display using light from the light source can be used. In particular, an electroluminescent element that can extract light emitted from a light-emitting substance by applying an electric field is preferably used. The light emitted from such a pixel is not affected by the brightness or chromaticity of the light, and therefore has high color reproducibility (wide color gamut) and high contrast, that is, vivid display. be able to.

  As the second display element, for example, a self-luminous light emitting element such as an OLED (Organic Light Emitting Diode), an LED (Light Emitting Diode), a QLED (Quantum-Dot Light Emitting Diode), or a semiconductor laser can be used. Alternatively, as the display element included in the second pixel, a combination of a backlight that is a light source and a transmissive liquid crystal element that controls the amount of light transmitted through the backlight may be used.

  For example, the first pixel may include a first display element that emits light of three colors of red (R), green (G), and blue (B). Similarly, the second pixel can include a second display element that emits light of three colors, for example, red (R), green (G), and blue (B). Note that the subpixels included in each of the first pixel and the second pixel may have four or more colors. As the number of subpixels increases, power consumption can be reduced and color reproducibility can be improved. Further, as the first display element included in the first pixel, cyan (C), magenta (M), and yellow (Y) instead of the three colors of red (R), green (G), and blue (B). When display elements that respectively exhibit the three colors of light are applied, brighter display becomes possible.

  Hereinafter, as an example of a display device of one embodiment of the present invention, a display device that includes both a reflective liquid crystal element and a light-emitting element and can perform display in a light-emitting mode, a reflective mode, and a hybrid mode ( An example of a display panel) will be described. Such a display panel can also be called ER-Hybrid Display (Emission and Reflection Hybrid Display or Emission / Reflection Hybrid Display).

  As an example of such a display panel, there is a configuration in which a liquid crystal element including an electrode that reflects visible light and a light emitting element are stacked. At this time, it is preferable that the electrode that reflects visible light has a notch in a part thereof, and the notch and the light emitting element are overlapped. The notch may be an opening. Thereby, in the light emission mode, it can drive so that the light from a light emitting element may be inject | emitted via the said notch part. Note that the electrode that reflects visible light does not have a notch, and the light emitting region of the light emitting element is disposed at a position that does not overlap with the electrode that reflects visible light, as viewed from the display surface side. Sometimes, the light emitted from the light emitting element may be emitted from the gap between the electrodes that reflect visible light.

  By stacking the liquid crystal element and the light emitting element, a pixel (also referred to as a pixel unit) having both the liquid crystal element and the light emitting element is compared with a case where the liquid crystal element and the light emitting element are arranged side by side in a plan view. Since the size can be reduced, a display device with higher definition can be realized.

  Such a display panel can be driven with extremely low power consumption by displaying in a reflection mode in an environment with bright external light such as outdoors. Further, in an environment where the outside light is dark such as at night or indoors, an image can be displayed with an optimum luminance by displaying in the light emission mode. Furthermore, by displaying in a mode using both light emission and reflected light (also called a hybrid mode), even in environments where the brightness of external light is insufficient, the power consumption is lower than in conventional display panels. In addition, display with high contrast can be performed. In the reflection mode and the hybrid mode, since the display reflecting the fluctuation of the ambient light can be performed, the display that the user feels more natural can be performed.

  In one embodiment of the present invention, a pixel electrode included in a reflective liquid crystal element is formed in a strip shape that is long in a first direction. Such pixel electrodes are arranged side by side in a second direction that intersects (preferably orthogonally) the first direction. At this time, the pixel electrode functions as a reflective electrode that reflects visible light.

  For example, the pixel electrodes of the three subpixels preferably have the same shape except that the positions and shapes of the notch portions described above are different. In addition, each shape should just be a substantially strip shape, and the shape of a detail may differ. Moreover, when the pixel electrode of a liquid crystal element does not have a notch part, it may be the same strip shape, respectively, and the detail shape may differ.

  In addition, a wiring functioning as a scanning line for driving a pixel (sub-pixel) having a reflective liquid crystal element extends in the first direction, and a wiring functioning as a signal line extends in the second direction. It is preferable to arrange in. Thereby, the number of signal lines can be reduced. Further, it is preferable that the liquid crystal element is arranged so that the longitudinal direction thereof is orthogonal to the signal line. As a result, the liquid crystal element is less susceptible to the influence of the electric field from the signal line, and the change in gradation during display is less likely to occur. In particular, when driving with a low driving frequency of the liquid crystal element, flicker caused by a change in the alignment of the liquid crystal becomes difficult to be seen, so that driving with low power consumption can be performed without sacrificing visibility. .

  On the other hand, the pixel electrodes included in the light-emitting elements are arranged in the first direction. At this time, the shape of the pixel electrode is preferably the same shape between the sub-pixels. For example, the shape of the pixel electrode of the three subpixels can be a strip shape that is long in the second direction. Note that each pixel electrode of the light emitting element may have a substantially strip shape, and the shape of the details may be different. For example, the area of the pixel electrode may be different. Further, by making the pixel electrodes have the same shape, the capacitance component and the resistance component can be made equal between the sub-pixels.

  In addition, a wiring functioning as a scanning line for driving a pixel (sub-pixel) having a light emitting element is arranged so as to extend in the second direction, and a wiring functioning as a signal line extends in the first direction. It is preferable. In particular, when different structures are used between light emitting elements exhibiting different colors, it is necessary to input different potentials from the signal lines to the sub-pixels even in the same gradation display. Therefore, the driving method can be simplified by adopting a configuration in which different signal lines are provided for each sub-pixel, instead of sharing the signal lines of the respective sub-pixels.

  That is, for example, when the display device includes a first pixel having a configuration in which three subpixels having a liquid crystal element are arranged and a second pixel having a configuration in which three subpixels having a light emitting element are arranged, Three scanning lines and one signal line are connected to the first pixel, and one scanning line and three signal lines are connected to the second pixel.

  In the display device, a scan line connected to a subpixel including a liquid crystal element and a scan line connected to a subpixel including a light emitting element can be arranged to extend in the same direction. In the display device, a signal line connected to a subpixel including a liquid crystal element and a signal line connected to a subpixel including a light emitting element can be arranged to extend in the same direction.

  Hereinafter, a more specific structure example of the display device of one embodiment of the present invention is described with reference to drawings.

[Configuration example]
FIG. 1A is a schematic diagram when one pixel 10p included in the display device is viewed from the display surface side. FIG. 1B is a schematic diagram when the layers of the pixel 10p are separated and viewed from an oblique direction. In FIGS. 1A and 1B, orthogonal X and Y directions are indicated by arrows, respectively.

  The pixel 10p includes three colored layers (colored layer 52R, colored layer 52G, colored layer 52B), three reflective liquid crystal elements 40, and three light emitting elements (light emitting element 60R, light emitting element 60G, and light emitting element 60B). Are stacked.

  Each of the light emitting element 60R, the light emitting element 60G, and the light emitting element 60B includes a conductive layer 61 that functions as a pixel electrode. Each light emitting element is provided on a part of the conductive layer 61. The conductive layer 61 has a strip shape (or a strip shape or a rectangular shape) extending in the Y direction. The three conductive layers 61 are arranged in the X direction. Here, the three conductive layers 61 have the same shape, but one or more of them may have different shapes.

  The liquid crystal element 40 includes a conductive layer 23 functioning as a pixel electrode, a conductive layer 25 functioning as a common electrode, and a liquid crystal 24 therebetween. In FIG. 1B, the liquid crystal 24 and the conductive layer 25 are indicated by broken lines. The conductive layer 23 has a strip shape extending in the X direction. The three conductive layers 23 are arranged in the Y direction.

  The colored layer 52R, the colored layer 52G, and the colored layer 52B are provided so as to overlap with any one of the conductive layers 23, respectively. The colored layer 52R, the colored layer 52G, and the colored layer 52B each have a strip shape extending in the X direction, and are arranged in the Y direction.

  Here, it can be said that the conductive layer 23 is rotated 90 degrees in the arrangement direction with the conductive layer 61 and the three colored layers. It can also be said that the conductive layer 61 and the three colored layers are arranged in the same direction.

  As shown in FIGS. 1A and 1B, one conductive layer 23 is disposed so as to overlap the three conductive layers 61. One conductive layer 23 has a notch portion 11a in a portion overlapping any one of the three light emitting elements (light emitting element 60R, light emitting element 60G, and light emitting element 60B). Here, the case where the shape of the notch 11a is an opening shape is shown. It can also be said that each of the light emitting element 60R, the light emitting element 60G, and the light emitting element 60B has a region overlapping with the notch portion 11a of the conductive layer 23.

  As shown in FIGS. 1A and 1B, the three colored layers (the colored layer 52R, the colored layer 52G, and the colored layer 52B) each have a notch portion 11b at a position overlapping the notch portion 11a. Have. Here, the case where the shape of the notch part 11b is an opening shape like the notch part 11a is shown. It can also be said that the light-emitting element 60R, the light-emitting element 60G, and the light-emitting element 60B each have a region that overlaps one cutout portion 11b of the colored layer 52R, the colored layer 52G, or the colored layer 52B.

  The light emitting element 60R emits light 20eR on the display surface side (upper side). Similarly, the light emitting element 60G emits light 20eG, and the light emitting element 60B emits light 20eB to the display surface side. The light 20eR, the light 20eG, and the light 20eB are emitted to the display surface side through the notch 11a and the notch 11b, respectively. For example, when the light 20eR is red light, the light 20eG is green light, and the light 20eB is blue light, color display can be performed by three light emitting elements.

  Each of the liquid crystal elements 40 reflects external light incident from the display surface side, and emits light 20rR, light 20rG, or light 20rB as reflected light to the display surface side. Here, the light 20rR is light that is colored by passing through the colored layer 52R located on the optical path twice. Similarly, the light 20rG and the light 20rB are also colored light by passing through the colored layer 52G and the colored layer 52B twice. For example, the colored layer 52R transmits red light, the colored layer 52G transmits green light, and the colored layer 52B transmits blue light. Thereby, color display can be performed by the three liquid crystal elements 40.

  Here, it is preferable that the color of light emitted from one light-emitting element and the color of light transmitted through the colored layer including the notch portion 11b through which the light emitted from the light-emitting element passes are matched. For example, when the light 20eR emitted from the light emitting element 60R is red light, the colored layer 52R is preferably a colored layer (color filter) that transmits red light. Thereby, for example, when a part of the light 20eR emitted from the light emitting element 60R reaches the colored layer 52R, it can be transmitted through the colored layer 52R and emitted to the display surface side. Therefore, the light extraction efficiency can be increased. Further, when a part of the light 20eR emitted from the light emitting element 60R reaches the colored layer of another color (the colored layer 52G or the colored layer 52G), color mixing can be prevented because it is absorbed by the colored layer.

  Similarly, when the light 20eG emitted from the light emitting element 60G is green light, the colored layer 52G is preferably a colored layer that transmits green light. In addition, when the light 20eB emitted from the light emitting element 60B is blue light, the colored layer 52B is preferably a colored layer that transmits blue light.

  In the structure shown in FIGS. 1A and 1B, the notch portion 11b of the colored layer is arranged on the optical path of the light emitted from each light emitting element, so that part of the light emitted from the light emitting element is colored. The light extraction efficiency can be increased without being absorbed by the layer.

  Note that the number and arrangement of the colored layers, the liquid crystal elements 40, and the light-emitting elements are not limited to this, and one or more may be provided depending on the configuration of the pixel. In the case where color display is not performed by the liquid crystal element 40, a configuration without a colored layer may be employed.

  FIG. 2 shows an example having three light emitting elements 60W that emit white light. Further, FIG. 2 shows an example in which the colored layer 52R, the colored layer 52G, and the colored layer 52B do not have the notch portion 11b.

  In the configuration illustrated in FIG. 2, light emitted from the light emitting element 60 </ b> W passes through any one of the colored layer 52 </ b> R, the colored layer 52 </ b> G, or the colored layer 52 </ b> B and is emitted to the outside as light 20 eR, light 20 eG, or light 20 eB. . Thereby, color display can be performed by the three light emitting elements 60W.

  In the configuration illustrated in FIG. 2, the light-emitting element 60W can have the same configuration between sub-pixels of different colors, so that the manufacturing process can be simplified.

[About wiring layout]
Here, an example of a wiring arrangement method for driving a liquid crystal element or a light emitting element will be described.

  3A illustrates an example of a method for arranging the three conductive layers 23, the conductive layer 12R, the conductive layer 12G, the conductive layer 12B, and the conductive layer 13 included in the liquid crystal element 40. FIG.

  The conductive layer 12R, the conductive layer 12G, and the conductive layer 12B function as scanning lines, extend in the X direction, and are arranged side by side in the Y direction. The conductive layer 13 functions as a signal line and extends in the Y direction.

  Here, the scanning line is a wiring which is connected to a subpixel having a liquid crystal element or a light emitting element and receives a signal for sequentially selecting the subpixel. The signal line is a wiring that is connected to a subpixel having a liquid crystal element or a light emitting element and to which a signal (for example, a video signal) input to the subpixel is applied.

  Here, as shown in FIG. 3A, each conductive layer 23 is preferably arranged so as not to overlap with the conductive layer 13 functioning as a signal line. Thereby, in addition to reducing the parasitic capacitance between the conductive layer 13 and each conductive layer 23, it is possible to suppress electrical noise from being transmitted from the conductive layer 13 to each conductive layer 23.

  FIG. 3B illustrates an example of a method for arranging the light-emitting element 60R, the light-emitting element 60G, the light-emitting element 60B, the three conductive layers 61, the conductive layer 14, the conductive layer 15R, the conductive layer 15G, and the conductive layer 15B. Yes.

  The conductive layer 14 functions as a scanning line and extends in the X direction. The conductive layer 15R, the conductive layer 15G, and the conductive layer 15B each function as a signal line, extend in the Y direction, and are arranged side by side in the X direction.

  Here, like the conductive layer 23, each conductive layer 61 is preferably disposed so as not to overlap the conductive layer 15R, the conductive layer 15G, and the conductive layer 15B that function as signal lines.

[Pixel configuration example]
Hereinafter, a more specific configuration example of the pixel included in the display device will be described.

  4A1 and 4A2 are examples of more specific pixel configurations corresponding to FIG. 3A, and show an example of a layout method when viewed from the display surface side. 4A1 is a schematic top view of a stage before the conductive layer 23 functioning as a pixel electrode is provided, and FIG. 4A2 is a schematic top view of the stage after the conductive layer 23 is provided. The figure is shown. For the sake of clarity, some components (such as insulating layers) are not explicitly shown in each drawing.

  4B1 and 4B2 are more specific pixel configuration examples corresponding to FIG. 3B. FIG. 4B1 is a schematic top view of the conductive layer 61 functioning as a pixel electrode and a stage before providing each light-emitting element, and FIG. 4B2 shows a stage after the provision of these. FIG.

  In the top schematic view shown here, the same hatching pattern is given to films obtained by processing the same film.

  The pixel illustrated in FIGS. 4A1 and 4A2 includes a transistor 70r. The transistor 70r functions as a selection transistor that controls the selection state of the sub-pixel. The transistor 70r is electrically connected to the conductive layer 12R, the conductive layer 12G, or the conductive layer 12B that functions as a scan line, and the conductive layer 13 that functions as a signal line.

  One of the transistors 70r includes a semiconductor layer 72 through an insulating layer (not shown) at a position overlapping with the conductive layer 12R functioning as a gate.

  FIG. 4C illustrates an example of a circuit diagram of a pixel corresponding to FIGS. 4A1 and 4A2. One sub-pixel 10LC includes a transistor 70r, a capacitor 90r, and a liquid crystal element 40R (or a liquid crystal element 40G or a liquid crystal element 40B). As the capacitor 90r, for example, an MIM type capacitor can be used, or a capacitor component of the transistor 70r, a capacitor component of the conductive layer 23, or the like can be used.

  In the transistor 70r, a gate is electrically connected to the conductive layer 12R (or the conductive layer 12G or the conductive layer 12B), one of a source or a drain is electrically connected to the conductive layer 13, and the other of the source or the drain is a capacitor. One terminal of 90r and one terminal (pixel electrode, conductive layer 23) of the liquid crystal element 40R (or the liquid crystal element 40G or the liquid crystal element 40B) are electrically connected.

  The pixel illustrated in FIGS. 4B1 and 4B2 includes a transistor 70e1, a transistor 70e2, and a capacitor 90e. In addition, the pixel includes a conductive layer 16 that functions as a wiring to which a power supply potential is supplied.

  FIG. 4D illustrates an example of a circuit diagram of a pixel corresponding to FIGS. 4B1 and 4B2. One subpixel 10EL includes a transistor 70e1, a transistor 70e1, a transistor 70e2, a capacitor 90e, and a light emitting element 60R (or the light emitting element 60G or the light emitting element 60B).

  In the transistor 70e1, a gate is electrically connected to the conductive layer 14, one of a source and a drain is electrically connected to the conductive layer 15R (or the conductive layer 15G or the conductive layer 15B), and the other is connected to the gate of the transistor 70e2. It is electrically connected to one terminal of the capacitive element 90e. In the transistor 70e2, one of a source and a drain is electrically connected to the conductive layer 16, and the other is electrically connected to one terminal (pixel electrode, conductive layer 61) of the light-emitting element 60R (or the light-emitting element 60G or the light-emitting element 60B). It is connected to the. The other terminal of the capacitor 90 e is electrically connected to the conductive layer 16.

  The above is the description of the configuration example of the pixel.

[Configuration example of display device]
FIG. 5A is a perspective view of the display device 10 of one embodiment of the present invention as viewed from the display surface side. The display device 10 includes a substrate 21 and a substrate 31. FIG. 5A shows the substrate 31 with broken lines.

  The display device 10 includes a display unit 32, a circuit unit 34, wirings 35, and the like between the substrate 21 and the substrate 31. FIG. 5A shows an example in which an IC 37 and an FPC 36 are mounted on the substrate 21. Therefore, the display device 10 illustrated in FIG. 5A can also be referred to as a display module.

  As the circuit unit 34, for example, a circuit that functions as a scanning line driver circuit can be used.

  The wiring 35 has a function of supplying a signal and power to the display unit 32 or the circuit unit 34. The signal and power are input from the outside via the FPC 36 or input from the IC 37.

  FIG. 5A illustrates an example in which the IC 37 is provided on the substrate 21 by a COG (Chip On Glass) method or the like. As the IC 37, for example, an IC having a function as a scan line driver circuit or a signal line driver circuit can be used. Note that the IC 37 may be omitted if not necessary. The IC 37 may be mounted on the FPC 36 by a COF (Chip On Film) method or the like.

  FIG. 5B illustrates an example of the touch panel 10 a including the display device 10.

  In the touch panel 10a, the touch sensor panel 50 is provided on the display surface side. In addition, a diffusion plate 38 and a polarizing plate 39 are provided between the display device 10 and the touch sensor panel 50 from the display device 10 side.

  As the diffusion plate 38, a film having a function of diffusing visible light can be suitably used. For example, a film on which a hemispherical lens or a microlens array is formed, a film with an uneven structure, a light diffusion film, or the like can be used. For example, the light extraction structure can be formed by bonding such a film using the substrate 31 or an adhesive having a refractive index comparable to that of the film.

  As the polarizing plate 39, for example, a linear polarizing plate or a circular polarizing plate may be used. In particular, when the display unit 32 includes a reflective liquid crystal element, a circularly polarizing plate can be preferably used. As a circularly-polarizing plate, what laminated | stacked the linearly-polarizing plate and the quarter wavelength phase difference plate, for example can be used. By using a circularly polarizing plate, an effect of suitably suppressing external light reflection can be added.

  The touch sensor panel 50 has a function of detecting that a detection target such as a finger or a stylus is touching or approaching. Moreover, you may have the function to output the positional information on a to-be-detected body. FIG. 5B shows an example in which the FPC 50 a is mounted on the touch sensor panel 50. The touch sensor panel 50 or the FPC 50a may be mounted with an IC or the like having a function of controlling driving of the touch sensor panel 50, a function of calculating position information from a signal from the touch sensor panel 50, or the like.

  As a detection element (also referred to as a sensor element) included in the touch sensor panel 50, various sensors that can detect that a detection target such as a finger or a stylus touches or approaches the surface of the touch sensor panel 50 are applied. can do.

  For example, various methods such as a capacitance method, a resistance film method, a surface acoustic wave method, an infrared method, an optical method, and a pressure-sensitive method can be used as a sensor method.

  Examples of the electrostatic capacity method include a surface electrostatic capacity method and a projection electrostatic capacity method. In addition, examples of the projected capacitance method include a self-capacitance method and a mutual capacitance method. Use of the mutual capacitance method is preferable because simultaneous multipoint detection is possible.

  In FIG. 5B, the display device 10 and the touch sensor panel 50 manufactured separately are bonded to each other, but the present invention is not limited to this. For example, a so-called on-cell type or in-cell type touch panel in which an electrode or the like constituting a detection element is provided on one or both of the substrate 21 and the substrate 31 of the display device 10 may be used.

  Moreover, it is preferable to use an antireflection film for the film used for the touch sensor panel 50. Alternatively, an antireflection film is preferably attached to the display surface side so as to overlap the touch sensor panel 50. Thereby, external light reflection of the surface of the touch panel 10a is suppressed, and visibility can be improved.

  In addition to the above, a functional film such as an antireflection film, a polarizing film, a retardation film, a light diffusing film, or a condensing film, an antistatic film that suppresses adhesion of dust, and dirt are disposed on the display surface side of the display device 10. You may provide the functional film containing the water-repellent film | membrane which makes it difficult to adhere, the hard coat film | membrane which suppresses generation | occurrence | production of the damage | wound accompanying use, the film | membrane which has the function to self-recover a damage | wound etc.

[Section configuration example]
Below, the example of the cross-sectional structure of a display apparatus is demonstrated with reference to drawings.

[Cross-section configuration example 1]
FIG. 6 shows a cross-sectional configuration example exemplified below. FIG. 6 is a cross-sectional configuration example corresponding to the configuration shown in FIG.

  The display device includes a transistor 70a, a transistor 70b, a light emitting element 60, a liquid crystal element 40, and the like between a substrate 21 and a substrate 31. In addition, an adhesive layer 89 is provided between the light emitting element 60 and the transistor 70b.

  The transistor 70a includes a conductive layer 71 that functions as a gate, an insulating layer 82 that partially functions as a gate insulating layer, a conductive layer 73a that functions as one of a source and a drain, and a conductive layer that functions as the other of a source and a drain 73b. The transistor 70a includes an insulating layer 83 that partially functions as a second gate insulating layer and a conductive layer 74 that functions as a second gate.

  The transistor 70b has a structure similar to that of the transistor 70a except that the transistor 70b does not have the second gate. Note that the transistor 70a and the transistor 70b may have the same structure or may have different structures.

  An insulating layer 81 is provided over the substrate 21, and a transistor 70 a is provided over the insulating layer 81. An insulating layer 82, an insulating layer 83, an insulating layer 84, an insulating layer 85, an insulating layer 86, and the like are provided over the insulating layer 81. The insulating layer 84, the insulating layer 85, and the insulating layer 86 are provided so as to cover the transistor 70a.

  The light emitting element 60 includes a conductive layer 61, a conductive layer 63, and an EL layer 62 positioned therebetween. An insulating layer 64 is provided so as to cover the conductive layer 63. The conductive layer 61 has a function of reflecting visible light, and the conductive layer 63 has a function of transmitting visible light. That is, the light emitting element 60 is a so-called top emission type light emitting element that emits light to the side opposite to the surface to be formed.

  The conductive layer 61 is provided on the insulating layer 85. The insulating layer 86 is provided so as to cover the end portion of the conductive layer 61. The conductive layer 61 is electrically connected to the conductive layer 73b through openings provided in the insulating layer 85, the insulating layer 84, the insulating layer 83, and the like, whereby the light-emitting element 60 and the transistor 70a are electrically connected. It is connected to the.

  The transistor 70b is provided on the substrate 21 side of the insulating layer 92. On the substrate 21 side of the insulating layer 92, an insulating layer 93, an insulating layer 94, an insulating layer 95, an insulating layer 96, and the like are stacked. A part of the insulating layer 93 functions as a first gate insulating layer of the transistor 70b. The insulating layer 96 preferably functions as a planarization layer. The insulating layer 96 may be omitted if unnecessary.

  A colored layer 54 a is provided on the insulating layer 95 on the substrate 21 side so as to overlap the light emitting element 60. As will be described later, the colored layer 54 may not be provided in the case where light emitting elements 60 exhibiting different colors are separately formed between pixels corresponding to different colors.

  Further, the insulating layer 64 and the insulating layer 96 are bonded together by an adhesive layer 89.

  On the substrate 31 side of the insulating layer 92, a conductive layer 23a and a conductive layer 23b are stacked. An insulating layer 91 is provided so as to cover the conductive layer 23a and the conductive layer 23b. An alignment film 26a is provided on the substrate 31 side of the conductive layer 23a.

  On the other hand, a colored layer 54b and an insulating layer 98 that covers the colored layer 54b are provided on the surface of the substrate 31 on the substrate 21 side. Further, the conductive layer 25 and the alignment film 26b are stacked on the substrate 21 side of the insulating layer 98.

  The liquid crystal 24 is sandwiched between the alignment film 26a and the alignment film 26b. A liquid crystal element 40 is configured by the conductive layer 23 a, the liquid crystal 24, and the conductive layer 25. Further, the substrate 31 and the insulating layer 91 are bonded together by an adhesive layer in a region not shown. The liquid crystal 24 is located in a region surrounded by the adhesive layer, and is sealed by the substrate 31, the insulating layer 91, and the adhesive layer.

  In addition, the display device includes a connection portion 80 that electrically connects conductive layers provided on both surfaces of the insulating layer 91. In FIG. 6, the connection portion 80 includes an opening provided in the insulating layer 91 and the insulating layer 92, a conductive layer that is obtained by processing the same conductive film as the gate of the transistor 70 b or the like, The structure which has is shown. One of a source and a drain of the transistor 70b and the conductive layer 23b are electrically connected through a connection portion 80.

  As shown in FIG. 6, the surface of the conductive layer 23 a is flat in a region overlapping with the connection portion 80. Therefore, the alignment defect of the liquid crystal 24 does not occur in the portion where the connection portion 80 is provided, so that it can function as a display region of the liquid crystal element 40. In particular, in a high-definition display device, since the ratio of the area of the connection portion 80 to the area occupied by one pixel is high, a high aperture ratio can be realized by using this region as a display region.

  The conductive layer 23a has a function of transmitting visible light. The conductive layer 23b has a function of reflecting visible light. Accordingly, the liquid crystal element 40 functions as a reflective liquid crystal element.

  Here, in FIG. 6, an insulating layer 97a is provided between the conductive layer 23a and the alignment film 26a. The insulating layer 97a is in contact with the insulating layer 91 in a region where the conductive layer 23a is not provided. An insulating layer 97b is provided between the conductive layer 25 and the alignment film 26b. For the insulating layer 97a and the insulating layer 97b, it is preferable to use an inorganic insulating material in which impurities such as water hardly diffuse. In this manner, by surrounding the liquid crystal 24 with the insulating layer 97a and the insulating layer 97b, it is possible to prevent impurities such as water from diffusing into the liquid crystal 24. Thereby, the resistivity of the liquid crystal element 40 can be kept high. In particular, it can be said that the configuration is suitable for driving the liquid crystal element 40 at a low frame frequency (for example, less than 1 Hz).

  The colored layer 54 b has a notch in a portion overlapping with the light emitting element 60. In other words, the colored layer 54b is not positioned on the optical path of the light emitted from the light emitting element 60. Thereby, the light extraction efficiency of the light emitting element 60 can be improved. In addition, by using different colored layers for the light emitting element 60 and the liquid crystal element 40, it is possible to apply a colored layer whose material and thickness are optimized for each of the light emitting element 60 and the liquid crystal element 40. .

  Here, the colored layer 54a and the colored layer 54b are preferably colored layers that transmit the same light.

  The above is the description of the cross-sectional configuration example 1.

[Cross-section configuration example 2]
The configuration shown in FIG. 7 is different from the configuration shown in FIG. 6 mainly in that the colored layer 54b does not have a notch and does not have the colored layer 54a. The configuration illustrated in FIG. 7 corresponds to the configuration illustrated in FIG.

  Thus, the structure can be simplified by using one colored layer 54 b for the light emitting element 60 and the liquid crystal element 40.

[Cross-section configuration example 3]
The configuration shown in FIG. 8 is different from the configuration shown in FIG. 6 mainly in that it has a substrate 21 a and an adhesive layer 88 instead of the substrate 21 and has a substrate 31 a instead of the substrate 31.

  The substrate 21a and the substrate 31a have flexibility. Therefore, the display device illustrated in FIG. 8 is a bendable display device.

  The substrate 21 a and the insulating layer 81 are bonded by an adhesive layer 88. By providing the insulating layer 81 functioning as a barrier layer between the transistor 70a and the substrate 21a, impurities can be prevented from diffusing into the transistor 70a.

  On the other hand, the colored layer 54b and the like are directly provided on the substrate 31a. Even in the case where a material that easily diffuses impurities such as water is used for the substrate 31a, the insulating layer 97b can be provided to prevent the impurities from diffusing into the liquid crystal 24.

[Cross-section configuration example 4]
The configuration shown in FIG. 9 is different from the configuration shown in FIG. 6 mainly in that the configuration of the light emitting element 60 is different and the colored layer 54a is not provided.

  FIG. 9 shows an example in which EL layers are separately formed for each adjacent light emitting element 60. A light-emitting element 60 illustrated in FIG. 9 includes an island-shaped EL layer 62a.

  With such a configuration, the light extraction efficiency of the light emitting element 60 can be increased, and the power consumption can be reduced.

  Note that only a part of the layers constituting the EL layer may be separately formed between the light emitting elements of different colors, and the other layers may be used in common. For example, a configuration in which only the light emitting layer is separately formed may be employed. In addition, among the three color light emitting layers, a light emitting layer exhibiting a color with the shortest wavelength (for example, a light emitting layer exhibiting blue light) may be provided over other display elements. Thereby, the formation process of the light emitting element 60 can be simplified.

[Cross-section configuration example 5]
The configuration illustrated in FIG. 10 is an example in the case where a bottom emission type light emitting element is applied to the light emitting element 60.

  In FIG. 10, the stacked structure from the insulating layer 81 to the insulating layer 64 shown in FIG.

  The insulating layer 81 is located closer to the display surface (substrate 31 side) than the transistor 70 a and is bonded to the insulating layer 86 through an adhesive layer 89. Further, the insulating layer 64 and the substrate 21 are bonded via an adhesive layer 88.

  In the light emitting element 60, the conductive layer 61 transmits visible light, and the conductive layer 63 reflects visible light. Therefore, the light emitted from the light emitting element 60 is emitted to the substrate 31 side.

[Cross-section configuration example 6]
The structure illustrated in FIG. 11 illustrates an example in which the direction of the transistor 70b illustrated in FIG.

  An insulating layer 91 is provided in contact with the adhesive layer 89, and the transistor 70b, the insulating layer 93, the insulating layer 94, the insulating layer 95, the insulating layer 96, and the like are provided over the insulating layer 91. A conductive layer 23b that reflects visible light is provided over the insulating layer 96, and a conductive layer 23a that transmits visible light is provided so as to cover the conductive layer 23b. An insulating layer 97a and an alignment film 26a are provided so as to cover the conductive layer 23a. The conductive layer 25b is electrically connected to one of a source and a drain of the transistor 70b through an opening provided in the insulating layer 96, the insulating layer 95, and the insulating layer 94. The colored layer 54 a is provided between the insulating layer 95 and the insulating layer 96.

  With such a structure, the temperature related to the manufacturing process of the transistor 70b can be increased; thus, the transistor 70b with higher reliability can be manufactured. For example, it is suitable when treatment at a high temperature of 450 ° C., 500 ° C., or 550 ° C. is required.

  The above is the description of the cross-sectional configuration example.

[Example of production method]
Hereinafter, an example of a method for manufacturing a display device of one embodiment of the present invention will be described with reference to drawings. Here, a method for manufacturing the display device exemplified in the cross-sectional configuration example 1 will be described.

  Each drawing shown in FIGS. 12 to 15 is a schematic cross-sectional view at each stage of the process according to a manufacturing method described below.

  Note that a thin film (an insulating film, a semiconductor film, a conductive film, or the like) included in the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, or a pulse laser deposition (PLD: Pulse Laser Deposition). ) Method, atomic layer deposition (ALD) method, or the like. Examples of the CVD method include a plasma enhanced chemical vapor deposition (PECVD) method and a thermal CVD method. As one of thermal CVD methods, there is a metal organic chemical vapor deposition (MOCVD) method.

  Thin films (insulating films, semiconductor films, conductive films, etc.) that constitute display devices are spin coat, dip, spray coating, ink jet, dispense, screen printing, offset printing, doctor knife, slit coat, roll coat, curtain coat. It can be formed by a method such as knife coating.

  Further, when a thin film included in the display device is processed, the thin film can be processed using a photolithography method or the like. In addition, the thin film may be processed by a nanoimprint method, a sand blast method, a lift-off method, or the like. Further, the island-shaped thin film may be directly formed by a film forming method using a shielding mask.

  As a photolithography method, there are typically the following two methods. One is a method in which a resist mask is formed on a thin film to be processed, the thin film is processed by etching or the like, and the resist mask is removed. The other is a method in which a thin film having photosensitivity is formed and then exposed and developed to process the thin film into a desired shape.

  In photolithography, light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or light obtained by mixing these. In addition, ultraviolet light, KrF laser light, ArF laser light, or the like can be used. Further, exposure may be performed by an immersion exposure technique. Further, extreme ultraviolet light (EUV: Extreme Ultra-violet) or X-rays may be used as light used for exposure. Further, an electron beam can be used instead of the light used for exposure. It is preferable to use extreme ultraviolet light, X-rays, or an electron beam because extremely fine processing is possible. Note that a photomask is not necessary when exposure is performed by scanning a beam such as an electron beam.

  For etching the thin film, a dry etching method, a wet etching method, a sand blasting method, or the like can be used.

[Formation of Insulating Layer 81]
First, the insulating layer 81 is formed over the substrate 21 (FIG. 12A).

  As the substrate 21, a substrate having rigidity to such an extent that it can be easily transported within the apparatus or between apparatuses can be used. In addition, a substrate having heat resistance to heat applied in the manufacturing process is used. For example, a glass substrate having a thickness of 0.3 mm to 1 mm can be used.

  The insulating layer 81 is provided, for example, to prevent impurities contained in the substrate 21 from diffusing. Further, when etching a thin film provided on the insulating layer 81, it may be used as an etching stopper for preventing the substrate 21 from being exposed. As the insulating layer 81, a thin film of an inorganic insulating material such as silicon nitride, silicon oxide, silicon oxynitride, or silicon nitride oxide can be used as a single layer or a stacked layer. Note that in this specification, oxynitride refers to a material having a higher oxygen content than nitrogen as its composition, and nitride oxide refers to a material having a higher nitrogen content than oxygen as its composition. Point to.

  Note that the insulating layer 81 is not necessarily provided if not necessary.

[Formation of Transistor 70a]
Subsequently, a conductive layer 71 is formed over the insulating layer 81. The conductive layer 71 can be formed by forming a conductive film, forming a resist mask, etching the conductive film, and then removing the resist mask.

  Subsequently, an insulating layer 82 is formed so as to cover the insulating layer 81 and the conductive layer 71.

  Subsequently, the semiconductor layer 72 is formed. The semiconductor layer 72 can be formed by forming a semiconductor film, forming a resist mask, etching the semiconductor film, and then removing the resist mask.

  Subsequently, a conductive layer 73a and a conductive layer 73b are formed. The conductive layer 73 a and the conductive layer 73 b can be formed by a method similar to that of the conductive layer 71.

  Subsequently, an insulating layer 83 is formed so as to cover the insulating layer 82, the conductive layer 73 a, the conductive layer 73 b, and the semiconductor layer 72.

  Subsequently, a conductive layer 74 that overlaps with the semiconductor layer 72 is formed over the insulating layer 83. The conductive layer 74 can be formed by a method similar to that of the conductive layer 71.

  Through the above steps, the transistor 70a can be formed (FIG. 12B).

[Formation of Insulating Layer 84 and Insulating Layer 85]
Next, an insulating layer 84 and an insulating layer 85 that cover the transistor 70a are formed (FIG. 12C).

  For the insulating layer 84, it is preferable to use a material in which water, hydrogen, and the like are difficult to diffuse. For example, an inorganic insulating film can be used as the insulating layer 84. As the insulating layer 84, a layer of an inorganic insulating material such as silicon nitride, silicon oxide, silicon oxynitride, silicon nitride oxide, aluminum oxide, aluminum nitride, aluminum oxynitride, or aluminum nitride oxide is formed as a single layer or a stacked layer. Can be used. Thus, the insulating layer 84 functions as a protective layer for the transistor 70a.

  Subsequently, an insulating layer 85 is formed so as to cover the insulating layer 84. It is preferable to use an organic insulating material for the insulating layer 85 because the flatness of the upper surface can be improved.

  As described above, since the insulating layer covering the transistor 70a has a stacked structure of the insulating layer 84 including an inorganic insulating material and the insulating layer 85 including an organic insulating material, both barrier properties and flatness can be achieved. preferable.

[Formation of Conductive Layer 61]
Subsequently, an opening reaching the conductive layer 73b and the like is formed in the insulating layer 85, the insulating layer 84, and the insulating layer 83.

  Subsequently, a conductive layer 61 that is electrically connected to the conductive layer 73 b is formed over the insulating layer 85. The conductive layer 61 can be formed by a method similar to that of the conductive layer 71 and the like.

[Formation of Insulating Layer 86]
Subsequently, an insulating layer 86 covering the end portion of the conductive layer 61 is formed (FIG. 12D). The insulating layer 86 can be formed by a method similar to that of the insulating layer 85 or the like.

[Formation of Light-Emitting Element 60]
Subsequently, an EL layer 62 and a conductive layer 63 are stacked over the portion where the upper surface of the conductive layer 61 is exposed and the insulating layer 86. Thereby, the light emitting element 60 is formed.

  The EL layer 62 can be typically formed by an evaporation method. In the case where at least one layer of the EL layer 62 is separately formed between pixels, the EL layer 62 can be formed by an evaporation method using a shielding mask such as a metal mask. Further, the EL layer 62 may be formed using an inkjet method or the like.

[Formation of Insulating Layer 64]
Subsequently, an insulating layer 64 is preferably formed over the conductive layer 63 (FIG. 12E). The insulating layer 64 is preferably formed by a film formation method such as a sputtering method or an ALD method that can form a dense film even when the formation temperature is lowered. Alternatively, a stacked structure of a film including an inorganic insulating material and a film including an organic insulating material may be employed.

  For example, it is preferable to form the insulating layer 64 having a stacked structure by forming an insulating film on the conductive layer 63 by a sputtering method and further forming an insulating film thereon by an ALD method. The sputtering method is easy to increase the deposition rate, and is suitable for forming an insulating film that is thick enough to obtain sufficient barrier performance. Furthermore, since the ALD method is a film formation method with extremely high step coverage, pinholes and defects in the insulating film formed by the sputtering method can be filled. By such a method, the insulating layer 64 having an extremely excellent barrier property can be formed.

[Formation of Release Layer 43a and Insulating Layer 97a]
A support substrate 44a is prepared, and a release layer 43a and an insulating layer 97a are stacked over the support substrate 44a.

  As the support substrate 44a, a substrate that is rigid to such an extent that it can be easily transferred within the apparatus or between apparatuses can be used. In addition, a substrate having heat resistance to heat applied in the manufacturing process is used. For example, a glass substrate having a thickness of 0.3 mm to 1 mm can be used.

  As a material used for the peeling layer 43a and the insulating layer 97a, a material that causes peeling in the interface between the peeling layer 43a and the insulating layer 97a or in the peeling layer 43a can be selected.

  For example, a layer containing a refractory metal material such as tungsten and a layer containing an oxide of the metal material are stacked as the separation layer 43a, and silicon nitride, silicon oxide, silicon oxynitride, or oxynitride is used as the insulating layer 97a. A layer of an inorganic insulating material such as silicon can be stacked. It is preferable to use a refractory metal material for the peeling layer 43a because processing at a high temperature is possible in the subsequent steps, and the degree of freedom in selecting a material and a formation method is increased.

  In the case where a stacked layer structure of tungsten and tungsten oxide is used as the separation layer 43a, separation can be performed at the interface between tungsten and tungsten oxide, in tungsten oxide, or at the interface between tungsten oxide and the insulating layer 97a.

  Alternatively, an organic resin may be used as the peeling layer 43a, and peeling may be performed at the interface between the support substrate 44a and the peeling layer 43a, in the peeling layer 43a, or at the interface between the peeling layer 43a and the insulating layer 97a.

  As the release layer 43a, a polyimide resin can be typically used. A polyimide resin is preferable because of its excellent heat resistance. In addition, as the peeling layer 43a, acrylic resin, epoxy resin, polyamide resin, polyimide amide resin, siloxane resin, benzocyclobutene resin, phenol resin, or the like can be used.

  The release layer 43a containing an organic resin is first a resin precursor by a method such as spin coating, dip, spray coating, ink jet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, knife coating, etc. A mixed material of the solvent and the solvent is formed on the support substrate 44a. Then, by performing heat treatment, the material can be cured while removing the solvent and the like, and the release layer 43a containing an organic resin can be formed.

  For example, when polyimide is used for the release layer 43a, a resin precursor in which an imide bond is generated by dehydration can be used. Alternatively, a material containing a soluble polyimide resin may be used.

  When an organic resin is used for the release layer 43a, either a photosensitive or non-photosensitive resin may be used. Since photosensitive polyimide is a material that is suitably used for a planarization film or the like of a display panel, a forming apparatus and a material can be shared. Therefore, no new device or material is required to realize the structure of one embodiment of the present invention. In addition, by using a photosensitive resin material, the release layer 43a can be processed by performing exposure and development processing. For example, an opening can be formed or an unnecessary portion can be removed. Further, by optimizing the exposure method and exposure conditions, it is possible to form a concavo-convex shape on the surface. For example, an exposure technique using a halftone mask or a gray tone mask, a multiple exposure technique, or the like may be used.

  When an organic resin is used for the peeling layer 43a, the peeling property may be improved by locally heating the peeling layer 43a. For example, irradiation with laser light can be given as a heating method. At this time, it is preferable to irradiate the laser beam by using a linear laser as the laser beam and scanning it. Thereby, the process time at the time of enlarging the area of a support substrate can be shortened. As the laser light, an excimer laser having a wavelength of 308 nm can be suitably used.

  When the peelability is improved by irradiating light such as laser light, a heat generating layer may be provided so as to overlap with the peelable layer 43a. The heat generation layer is a layer having a function of absorbing light and generating heat. The heat generating layer is preferably provided between the support substrate 44a and the release layer 43a, but may be disposed on the release layer 43a. As the heat generating layer, a material that can absorb part of light used for laser light or the like can be used. For example, when an excimer laser with a wavelength of 308 nm is used as the laser light, a metal, an oxide, or the like can be used for the heat generating layer. For example, a metal such as titanium or tungsten, an oxide conductor material such as titanium oxide, tungsten oxide, indium oxide, or indium tin oxide, or an oxide semiconductor material containing indium can be used.

  In addition, a layer containing oxygen, hydrogen, water, or the like is provided in contact with the separation layer 43a, and oxygen, hydrogen, water, or the like is supplied into the separation layer 43a or an interface between the separation layer 43a and the layer by heat treatment. By doing so, the peelability may be improved. Alternatively, oxygen, hydrogen, water, or the like may be supplied to the support substrate 44a. Alternatively, oxygen, hydrogen, water, or the like may be supplied to the peeling layer 43a. By performing heat treatment or plasma treatment in an atmosphere containing oxygen, hydrogen, water, or the like, these can be supplied to the support substrate 44a and the separation layer 43a. Accordingly, since it is not necessary to use a laser device or the like, a display device can be manufactured at a lower cost.

  In addition, the peeling layer 43 a may remain on the light path of the light emitting element 60 or the liquid crystal element 40 after peeling. When the peeling layer 43a absorbs a part of visible light, the light transmitted through the peeling layer 43a may be colored. Therefore, after peeling, it is preferable to remove this by etching. For example, when an organic resin is used for the peeling layer 43a, the remaining peeling layer 43a can be removed by plasma treatment (also referred to as ashing treatment) or the like in an atmosphere containing oxygen.

[Formation of Conductive Layer 23a and Conductive Layer 23b]
Subsequently, a conductive layer 23a is formed over the insulating layer 97a. As the conductive layer 23a, an oxide conductive material is preferably used. By using an oxide conductive material for the conductive layer 23a, light can be transmitted even if the conductive layer 23a is located on the optical path of the light-emitting element 60. As the conductive layer 23a, for example, a metal oxide or a low-resistance oxide semiconductor material can be used.

  In the case where an oxide semiconductor material is used for the conductive layer 23a, the carrier density may be increased by causing oxygen vacancies in the oxide semiconductor material by plasma treatment, heat treatment, or the like. The carrier density may be increased by introducing impurities such as rare gas such as argon in addition to hydrogen and nitrogen into the oxide semiconductor material. Alternatively, as the conductive layer 23b formed over the conductive layer 23a, oxygen in the oxide semiconductor may be reduced by using a material in which oxygen is easily diffused. Two or more methods described above may be applied.

  Subsequently, a conductive layer 23b having an opening is formed over the conductive layer 23a (FIG. 13A). As the conductive layer 23b, a material that reflects visible light can be used. For example, a single layer structure including a metal or an alloy material or a stacked structure can be used. In the case of using a stacked structure as the conductive layer 23b, it is preferable to use a material having higher reflectance than the other layers for the layer in contact with the conductive layer 23a.

[Formation of Insulating Layer 91 and Insulating Layer 92]
Subsequently, an insulating layer 91 and an insulating layer 92 are stacked to cover the conductive layer 23a and the conductive layer 23b (FIG. 13B). It is preferable to use an inorganic insulating material for each of the insulating layer 91 and the insulating layer 92.

  Note that in FIG. 13B and the like, the top surface of the insulating layer 92 is shown to be flat, but actually, the insulating layer 92 may have a concavo-convex shape reflecting the top surface shape of the layer provided below.

[Formation of connecting portion 80]
Subsequently, an opening reaching the conductive layer 23 b is formed in the insulating layer 92 and the insulating layer 91.

  Subsequently, a conductive layer 71 is formed over the insulating layer 92. At the same time, a conductive layer electrically connected to the conductive layer 23b is formed in the insulating layer 92 and a portion overlapping the opening provided in the insulating layer 91. Thus, the connection portion 80 can be formed (FIG. 13C).

[Formation of Transistor 70b]
Subsequently, the insulating layer 93, the semiconductor layer 72, the conductive layer 73a, and the conductive layer 73b are formed, whereby the transistor 70b is formed. After that, an insulating layer 94 and an insulating layer 95 are formed so as to cover the transistor 70b and the like (FIG. 13D).

  The insulating layer 93 and the insulating layer 94 can be formed by a method similar to that for the insulating layer 82 or the insulating layer 83. The insulating layer 95 can be formed by a method similar to that for the insulating layer 84.

[Formation of colored layer 54]
Subsequently, a colored layer 54 a is formed on the insulating layer 95. The colored layer 54 can be formed by applying a photosensitive material and then performing an exposure process and a development process. The colored layer 54 is separately formed between pixels of different colors.

[Formation of Insulating Layer 96]
Subsequently, an insulating layer 96 is formed so as to cover the insulating layer 95, the light reflecting layer 15b, the colored layer 54, and the like (FIG. 13E). The insulating layer 96 can be formed by a method similar to that of the insulating layer 85.

[Lamination of support substrate 44b]
Subsequently, the supporting substrate 44b and the insulating layer 96 are bonded using the adhesive layer 46a (FIG. 14A). The support substrate 44b can be made of the same material as the support substrate 44a. The adhesive layer 46a is preferably made of a material that can be easily peeled later. For example, an adhesive material, a double-sided tape, a silicone sheet, or a water-soluble adhesive can be used as the adhesive layer 46a.

[Peeling of support substrate 44a]
Subsequently, separation is performed between the separation layer 43a and the insulating layer 97a, and the support substrate 44a and the separation layer 43a are removed (FIG. 14B).

  As a method for separating the insulating layer 97a and the support substrate 44a, mechanical force is applied, the release layer is etched, a liquid is dropped on the end of the support substrate 44a, or the support substrate 44a is liquidized. For example, it is impregnated with a liquid, and a liquid is allowed to permeate the peeling interface. Alternatively, peeling may be performed by heating or cooling the support substrate 44a using a difference in thermal expansion coefficient between the two layers forming the peeling interface.

  Moreover, you may perform the process which exposes a part of peeling interface before peeling. For example, a part of the insulating layer 97a on the peeling layer 43a is removed by a laser or a sharp member. As a result, the separation can proceed with the portion from which the insulating layer 97a has been removed as the starting point (starting point).

  Further, as described above, the peelability may be improved by irradiating the release layer 43a or the like with laser light. Alternatively, the peelability may be improved by performing heat treatment in the process from the formation of the release layer 43a to the release process.

  After the separation, a part of the separation layer 43a may remain on the surface of the insulating layer 97a. In that case, the remaining peeling layer 43a may be removed by cleaning, etching, plasma treatment, wiping, or the like. Further, when the remaining peeling layer 43a does not affect the operation of the display device or the display quality, it may not be removed. In that case, a layer containing an element contained in the separation layer 43a remains in contact with the surface of the insulating layer 97a.

  In addition, when the insulating layer 97a is unnecessary, the insulating layer 97a may be removed. The insulating layer 97a can be removed by, for example, a dry etching method or a wet etching method. By removing the insulating layer 97a, the surfaces of the conductive layer 23b and the insulating layer 91 are exposed.

  Note that in the case where the insulating layer 97a has a light-transmitting property, it may not be removed. Thus, the insulating layer 97a can be used as a barrier layer. In that case, if the insulating layer 97a is too thick, the driving voltage of the liquid crystal element 40 may increase. Therefore, the insulating layer 97a may be thinned by the etching method.

[Formation of Alignment Film 26a]
Subsequently, an alignment film 26a is formed over the conductive layer 23a (FIG. 14C). The alignment film 26a can be formed by performing a rubbing process after forming a thin film.

  Note that when an organic resin is used for the peeling layer 43a and peeling is performed between the peeling layer 43a and the support substrate 44a, the alignment film 26a may be formed by rubbing without removing the peeling layer 43a. At this time, it is preferable that the insulating layer 97a is formed in advance so thin that the barrier property is not lost.

[Preparation of substrate 31]
Subsequently, a substrate in which the colored layer 54b, the insulating layer 98, the conductive layer 25, the insulating layer 97b, the alignment film 26b, and the like are formed on the substrate 31 in advance is prepared. The colored layer 54b can be formed by a method similar to that of the colored layer 54a. The insulating layer 98 can be formed by a method similar to that for the insulating layer 96. The conductive layer 25 can be formed by a method similar to that of the conductive layer 23a. The alignment film 26b can be formed by the same method as the alignment film 26a.

[Lamination of support substrate 44b and substrate 31]
Subsequently, an adhesive layer (not shown) for bonding them is formed on one or both of the support substrate 44b and the substrate 31. The adhesive layer is formed so as to surround a region where the pixels are arranged. The adhesive layer can be formed by, for example, a screen printing method or a dispensing method. As the adhesive layer, a thermosetting resin, an ultraviolet curable resin, or the like can be used. Alternatively, a resin that is cured by applying heat after being temporarily cured by ultraviolet rays may be used. Alternatively, as the adhesive layer, a resin having both ultraviolet curable properties and thermosetting properties may be used.

  Subsequently, the composition containing the liquid crystal 24 is dropped onto a region surrounded by the adhesive layer by a dispensing method or the like. Further, the composition may contain a chiral agent or the like.

  Subsequently, the support substrate 44b and the substrate 31 are bonded so as to sandwich the liquid crystal 24, and the adhesive layer is cured. Bonding is preferably performed in a reduced-pressure atmosphere because air bubbles can be prevented from being mixed between the support substrate 44b and the substrate 31.

  Note that the composition containing the liquid crystal 24 may be injected from a gap provided in the adhesive layer in a reduced-pressure atmosphere after the support substrate 44b and the substrate 31 are bonded to each other. In addition, after the composition containing the liquid crystal 24 is dropped, a granular gap spacer may be arranged in the region where the pixels are arranged or outside the region, or the composition containing the gap spacer may be dropped. Good.

  The liquid crystal element 40 is formed by bonding the substrate 31 and the support substrate 44b. A schematic cross-sectional view at this stage corresponds to FIG.

[Removal of support substrate 44b]
Subsequently, the adhesive layer 46a and the support substrate 44b are removed. A schematic cross-sectional view at this stage corresponds to FIG.

[Lamination of substrate 21 and substrate 31]
Finally, as shown in FIG. 16, after bonding the substrate 21 and the substrate 31 with the adhesive layer 89 interposed therebetween, the adhesive layer 89 is cured.

  The adhesive layer 89 may be formed by applying to one or both of the substrate 21 and the substrate 31. For example, it can be formed by a screen printing method, a dispensing method, or the like. Alternatively, for example, a sheet-like or film-like adhesive may be used as the adhesive layer 89. For example, an OCA (Optical Clear Adhesive) film can be suitably used.

  Through the above process, the display device illustrated in FIG. 6 can be manufactured.

  The above is the description of the manufacturing method example.

[About transistors]
Hereinafter, structural examples of transistors that can be used for the display device of one embodiment of the present invention are described.

  The transistor exemplified below can be used in place of the transistor 70a, the transistor 70b, or the like.

  A transistor 110 illustrated in FIG. 17A is a bottom-gate transistor.

  The transistor 110 is provided over the insulating layer 131. The transistor 110 includes a conductive layer 111 functioning as a gate electrode, a part of the insulating layer 132 functioning as a gate insulating layer, a semiconductor layer 112, a conductive layer 113a functioning as one of a source electrode and a drain electrode, and a source electrode Or a conductive layer 113b functioning as the other of the drain electrodes.

  In FIG. 17A, an insulating layer 133 that covers the transistor 110, an insulating layer 134 that functions as a planarization layer, a conductive layer 121 that is electrically connected to the conductive layer 113b and functions as a pixel electrode, and conductive An insulating layer 135 covering the end of the layer 121 is shown.

  In the transistor 110, the conductive layer 111 functioning as a gate electrode is located on the formation surface side (insulating layer 131 side) of the semiconductor layer 112. An insulating layer 132 is provided to cover the conductive layer 111. The semiconductor layer 112 is provided so as to cover the conductive layer 111. A region of the semiconductor layer 112 that overlaps with the conductive layer 111 corresponds to a channel formation region. In addition, the conductive layer 113a and the conductive layer 113b are provided in contact with the upper surface and the side end portion of the semiconductor layer 112, respectively.

  Note that the transistor 110 illustrates an example in which the width of the semiconductor layer 112 is larger than that of the conductive layer 111. With such a structure, the semiconductor layer 112 is disposed between the conductive layer 111 and the conductive layer 113a or the conductive layer 113b, so that the parasitic capacitance between the conductive layer 111 and the conductive layer 113a or the conductive layer 113b is reduced. Can do.

  The transistor 110 is a channel-etched transistor and can be suitably used for a high-definition display device because it is relatively easy to reduce the area occupied by the transistor.

  A transistor 110 a illustrated in FIG. 17B is different from the transistor 110 in that the transistor 110 a includes a conductive layer 114 and an insulating layer 136. The conductive layer 114 is provided over the insulating layer 133 and has a region overlapping with the semiconductor layer 112. The insulating layer 136 is provided so as to cover the conductive layer 114 and the insulating layer 133.

  The conductive layer 114 is located on the side opposite to the conductive layer 111 with the semiconductor layer 112 interposed therebetween. In the case where the conductive layer 111 is a first gate electrode, the conductive layer 114 can function as a second gate electrode. By applying the same potential to the conductive layer 111 and the conductive layer 114, the on-state current of the transistor 110a can be increased. The threshold voltage of the transistor 110a can be controlled by applying a potential for controlling the threshold voltage to one of the conductive layers 111 and 114 and a potential for driving the other.

  Here, a conductive material containing an oxide is preferably used for the conductive layer 114. Thus, oxygen can be supplied to the insulating layer 133 by forming the conductive film that forms the conductive layer 114 in an atmosphere containing oxygen. Preferably, the proportion of oxygen gas in the film forming gas is in the range of 90% to 100%. Oxygen supplied to the insulating layer 133 is supplied to the semiconductor layer 112 by a subsequent heat treatment, so that oxygen vacancies in the semiconductor layer 112 can be reduced.

  In particular, the conductive layer 114 is preferably formed using a low-resistance oxide semiconductor. At this time, an insulating film that releases hydrogen, for example, a silicon nitride film or the like is preferably used for the insulating layer 136. Hydrogen is supplied into the conductive layer 114 during the formation of the insulating layer 136 or by heat treatment thereafter, so that the electrical resistance of the conductive layer 114 can be effectively reduced.

  A transistor 110b illustrated in FIG. 17C is a top-gate transistor.

  In the transistor 110b, the conductive layer 111 functioning as a gate electrode is provided above the semiconductor layer 112 (on the side opposite to the formation surface). In addition, the semiconductor layer 112 is formed over the insulating layer 131. Further, an insulating layer 132 and a conductive layer 111 are stacked over the semiconductor layer 112. The insulating layer 133 is provided so as to cover the upper surface and side edges of the semiconductor layer 112, the side surface of the insulating layer 133, and the conductive layer 111. The conductive layer 113 a and the conductive layer 113 b are provided over the insulating layer 133. The conductive layer 113a and the conductive layer 113b are electrically connected to the upper surface of the semiconductor layer 112 through an opening provided in the insulating layer 133.

  Note that although the example in which the insulating layer 132 does not exist in a portion that does not overlap with the conductive layer 111 is shown here, the insulating layer 132 may be provided so as to cover the upper surface and the side end portion of the semiconductor layer 112. .

  Since the transistor 110b can easily separate a physical distance between the conductive layer 111 and the conductive layer 113a or the conductive layer 113b, parasitic capacitance between the conductive layer 111 and the conductive layer 113a can be reduced.

  A transistor 110c illustrated in FIG. 17D is different from the transistor 110b in that the transistor 110c includes a conductive layer 115 and an insulating layer 137. The conductive layer 115 is provided over the insulating layer 131 and has a region overlapping with the semiconductor layer 112. The insulating layer 137 is provided so as to cover the conductive layer 115 and the insulating layer 131.

  The conductive layer 115 functions as a second gate electrode like the conductive layer 114. Therefore, it is possible to increase the on-current, control the threshold voltage, and the like.

  FIG. 17E illustrates a structure in which the transistor 110 and the transistor 110d are stacked. The transistor 110d is a transistor having a pair of gate electrodes.

  The transistor 110d includes a part of the conductive layer 113b functioning as the first gate electrode, a part of the insulating layer 133 functioning as the first gate insulating layer, the semiconductor layer 112a, and one of the source electrode and the drain electrode. A conductive layer 113c that functions, a conductive layer 113d that functions as the other of the source electrode and the drain electrode, a part of the insulating layer 136 that functions as the second gate insulating layer, and a conductive layer 114a that functions as the second gate electrode And having.

  Such a configuration can be preferably applied particularly to a circuit for driving a light emitting element. That is, the transistor 110 is used as a transistor (also referred to as a switching transistor or a selection transistor) that controls the selection / non-selection state of a pixel, and the transistor 110d is used as a transistor (also referred to as a drive transistor) that controls a current flowing through the light-emitting element 120. It is preferable to use it.

  In the structure illustrated in FIG. 17E, a conductive layer 114b formed by processing the same conductive film as the conductive layer 114a is electrically connected to the conductive layer 113c through an opening provided in the insulating layer 136. ing. In addition, the conductive layer 121 is electrically connected to the conductive layer 114 b through an opening provided in the insulating layer 134.

[About each component]
Below, each component shown above is demonstrated.

  As the substrate included in the display device, a material having a flat surface can be used. For the substrate from which light from the display element is extracted, a material that transmits the light is used. For example, materials such as glass, quartz, ceramic, sapphire, and organic resin can be used.

  By using a thin substrate, the display device can be reduced in weight and thickness. Furthermore, a flexible display device can be realized by using a flexible substrate.

  Further, since the substrate on the side from which light emission is not extracted does not have to be translucent, a metal substrate or the like can be used in addition to the above-described substrates. A metal substrate is preferable because it has high thermal conductivity and can easily conduct heat to the entire substrate, which can suppress a local temperature increase of the display device. In order to obtain flexibility and bendability, the thickness of the metal substrate is preferably 10 μm to 200 μm, and more preferably 20 μm to 50 μm.

  Although there is no limitation in particular as a material which comprises a metal substrate, For example, metals, such as aluminum, copper, nickel, or alloys, such as aluminum alloy or stainless steel, can be used suitably.

  Alternatively, a substrate that has been subjected to an insulating process by oxidizing the surface of the metal substrate or forming an insulating film on the surface may be used. For example, the insulating film may be formed by using a coating method such as a spin coating method or a dip method, an electrodeposition method, a vapor deposition method, or a sputtering method, or it is left in an oxygen atmosphere or heated, or an anodic oxidation method. For example, an oxide film may be formed on the surface of the substrate.

Examples of the material having flexibility and transparency to visible light include, for example, glass having a thickness having flexibility, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and polyacrylonitrile resin. , Polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyvinyl chloride resin, polytetrafluoroethylene (PTFE) resin Etc. In particular, a material having a low thermal expansion coefficient is preferably used. For example, a polyamideimide resin, a polyimide resin, PET, or the like having a thermal expansion coefficient of 30 × 10 ⁻⁶ / K or less can be suitably used. Further, a substrate in which glass fiber is impregnated with an organic resin, or a substrate in which an inorganic filler is mixed with an organic resin to reduce the thermal expansion coefficient can be used. Since a substrate using such a material is light, a display device using the substrate can be light.

  When a fibrous body is included in the material, a high-strength fiber of an organic compound or an inorganic compound is used for the fibrous body. The high-strength fiber specifically refers to a fiber having a high tensile modulus or Young's modulus, and representative examples include polyvinyl alcohol fiber, polyester fiber, polyamide fiber, polyethylene fiber, aramid fiber, Examples include polyparaphenylene benzobisoxazole fibers, glass fibers, and carbon fibers. Examples of the glass fiber include glass fibers using E glass, S glass, D glass, Q glass, and the like. These may be used in the form of a woven fabric or a non-woven fabric, and a structure obtained by impregnating the fiber body with a resin and curing the resin may be used as a flexible substrate. When a structure made of a fibrous body and a resin is used as the flexible substrate, it is preferable because reliability against breakage due to bending or local pressing is improved.

  Alternatively, glass, metal, or the like thin enough to have flexibility can be used for the substrate. Alternatively, a composite material in which glass and a resin material are bonded to each other with an adhesive layer may be used.

  A hard coat layer (for example, silicon nitride, aluminum oxide) that protects the surface of the display device from scratches, a layer of a material that can disperse the pressure (for example, aramid resin), etc. on a flexible substrate It may be laminated. In order to suppress a decrease in the lifetime of the display element due to moisture or the like, an insulating film with low water permeability may be stacked over a flexible substrate. For example, an inorganic insulating material such as silicon nitride, silicon oxynitride, silicon nitride oxide, aluminum oxide, or aluminum nitride can be used.

  The substrate can be used by stacking a plurality of layers. In particular, when the glass layer is used, the barrier property against water and oxygen can be improved, and a highly reliable display device can be obtained.

[Transistor]
The transistor includes a conductive layer that functions as a gate electrode, a semiconductor layer, a conductive layer that functions as a source electrode, a conductive layer that functions as a drain electrode, and an insulating layer that functions as a gate insulating layer. The above shows the case where a bottom-gate transistor is applied.

  Note that there is no particular limitation on the structure of the transistor included in the display device of one embodiment of the present invention. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. Further, a top-gate or bottom-gate transistor structure may be employed. Alternatively, gate electrodes may be provided above and below the channel.

  There is no particular limitation on the crystallinity of a semiconductor material used for the transistor, and any of an amorphous semiconductor and a semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor partially including a crystal region) is used. May be used. It is preferable to use a crystalline semiconductor because deterioration of transistor characteristics can be suppressed.

  As a semiconductor material used for the transistor, for example, a Group 14 element (silicon, germanium, or the like), a compound semiconductor, or a metal oxide can be used for the semiconductor layer. Typically, a semiconductor containing silicon, a semiconductor containing gallium arsenide, a metal oxide containing indium, or the like can be used.

  In particular, it is preferable to use a metal oxide having a larger band gap than silicon. It is preferable to use a semiconductor material with a wider band gap and lower carrier density than silicon because current in an off state of the transistor can be reduced.

  In particular, the semiconductor layer has a plurality of crystal parts, and the crystal part has a c-axis oriented substantially perpendicular to the formation surface of the semiconductor layer or the top surface of the semiconductor layer, and there is no grain between adjacent crystal parts. It is preferable to use a metal oxide whose boundary cannot be confirmed.

  Since such a metal oxide does not have a crystal grain boundary, the occurrence of cracks in the metal oxide film due to stress when the display panel is curved is suppressed. Therefore, such a metal oxide can be suitably used for a display device that has flexibility and is bent.

  In addition, by using a metal oxide having such crystallinity as a semiconductor layer, a change in electrical characteristics is suppressed and a highly reliable transistor can be realized.

  In addition, a transistor using a metal oxide having a larger band gap than silicon can hold charge accumulated in a capacitor connected in series with the transistor for a long time due to its low off-state current. . By applying such a transistor to a pixel, the driving circuit can be stopped while maintaining the gradation of each pixel. As a result, a display device with extremely reduced power consumption can be realized.

  The semiconductor layer is represented by an In-M-Zn-based oxide containing at least indium, zinc, and M (metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium). It is preferable to include a film. In addition, in order to reduce variation in electric characteristics of the transistor using the metal oxide, it is preferable to include a stabilizer together with them.

  Examples of the stabilizer include the metals described in M above, and examples include gallium, tin, hafnium, aluminum, and zirconium. Other stabilizers include lanthanoids such as lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

  As a metal oxide forming the semiconductor layer, for example, an In—Ga—Zn-based oxide, an In—Al—Zn-based oxide, an In—Sn—Zn-based oxide, an In—Hf—Zn-based oxide, an In— La-Zn oxide, In-Ce-Zn oxide, In-Pr-Zn oxide, In-Nd-Zn oxide, In-Sm-Zn oxide, In-Eu-Zn oxide In-Gd-Zn-based oxide, In-Tb-Zn-based oxide, In-Dy-Zn-based oxide, In-Ho-Zn-based oxide, In-Er-Zn-based oxide, In-Tm -Zn oxide, In-Yb-Zn oxide, In-Lu-Zn oxide, In-Sn-Ga-Zn oxide, In-Hf-Ga-Zn oxide, In-Al- Ga-Zn oxide, In-Sn-Al-Zn oxide, In-Sn-Hf-Zn acid Things, can be used In-Hf-Al-Zn-based oxide.

  Note that here, an In—Ga—Zn-based oxide means an oxide containing In, Ga, and Zn as its main components, and there is no limitation on the ratio of In, Ga, and Zn. Moreover, metal elements other than In, Ga, and Zn may be contained.

  In addition, the semiconductor layer and the conductive layer may have the same metal element among the above oxides. Manufacturing costs can be reduced by using the same metal element for the semiconductor layer and the conductive layer. For example, the manufacturing cost can be reduced by using metal oxide targets having the same metal composition. Further, an etching gas or an etching solution for processing the semiconductor layer and the conductive layer can be used in common. However, the semiconductor layer and the conductive layer may have different compositions even if they have the same metal element. For example, a metal element in a film may be detached during a manufacturing process of a transistor and a capacitor to have a different metal composition.

  The metal oxide constituting the semiconductor layer preferably has an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more. In this manner, off-state current of a transistor can be reduced by using a metal oxide having a wide energy gap.

  In the case where the metal oxide forming the semiconductor layer is an In-M-Zn oxide, the atomic ratio of the metal elements of the sputtering target used for forming the In-M-Zn oxide is In ≧ M, Zn ≧ It is preferable to satisfy M. As the atomic ratio of the metal elements of such a sputtering target, In: M: Zn = 1: 1: 1, In: M: Zn = 1: 1: 1.2, In: M: Zn = 3: 1: 2, 4: 2: 4.1 and the like are preferable. Note that the atomic ratio of the semiconductor layer to be formed includes a variation of plus or minus 40% of the atomic ratio of the metal element contained in the sputtering target as an error.

As the semiconductor layer, a metal oxide film with low carrier density is used. For example, the semiconductor layer has a carrier density of 1 × 10 ¹⁷ / cm ³ or less, preferably 1 × 10 ¹⁵ / cm ³ or less, more preferably 1 × 10 ¹³ / cm ³ or less, more preferably 1 × 10 ¹¹ / cm 3. ³ or less, more preferably less than 1 × 10 ¹⁰ / cm ³ , and a metal oxide of 1 × 10 ⁻⁹ / cm ³ or more can be used. Such metal oxides are referred to as high purity intrinsic or substantially high purity intrinsic metal oxides. Accordingly, it can be said that the metal oxide has stable characteristics because the impurity concentration is low and the density of defect states is low.

  Note that the composition is not limited thereto, and a transistor having an appropriate composition may be used depending on required semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, and the like) of the transistor. In addition, in order to obtain the required semiconductor characteristics of the transistor, it is preferable that the semiconductor layer have appropriate carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, and the like. .

If the metal oxide constituting the semiconductor layer contains silicon or carbon which is one of the Group 14 elements, oxygen vacancies increase in the semiconductor layer and become n-type. Therefore, the concentration of silicon or carbon in the semiconductor layer (concentration obtained by secondary ion mass spectrometry) is 2 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁷ atoms / cm ³ or less.

In addition, when an alkali metal and an alkaline earth metal are combined with a metal oxide, carriers may be generated, which may increase the off-state current of the transistor. Therefore, the concentration of alkali metal or alkaline earth metal obtained by secondary ion mass spectrometry in the semiconductor layer is set to 1 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁶ atoms / cm ³ or less.

In addition, when nitrogen is contained in the metal oxide constituting the semiconductor layer, electrons as carriers are generated, the carrier density is increased, and the n-type is easily obtained. As a result, a transistor using a metal oxide containing nitrogen is likely to be normally on. For this reason, it is preferable that the nitrogen concentration obtained by secondary ion mass spectrometry in the semiconductor layer is 5 × 10 ¹⁸ atoms / cm ³ or less.

  The semiconductor layer may have a non-single crystal structure, for example. The non-single-crystal structure is, for example, a CAAC-OS (C-Axis Crystalline Oxide Semiconductor Semiconductor, or C-Axis Aligned and A-B-Plane Annealed Crystalline Oxide Semiconductor Crystal Structure, Amorphous Crystal Structure, Includes structure. In the non-single-crystal structure, the amorphous structure has the highest density of defect states, and the CAAC-OS has the lowest density of defect states.

  An amorphous metal oxide film has, for example, disordered atomic arrangement and no crystal component. Alternatively, an amorphous oxide film has, for example, a completely amorphous structure and does not have a crystal part.

  Note that the semiconductor layer may be a mixed film including two or more of an amorphous structure region, a microcrystalline structure region, a polycrystalline structure region, a CAAC-OS region, and a single crystal structure region. Good. For example, the mixed film may have a single-layer structure or a stacked structure including any two or more of the above-described regions.

<Configuration of CAC-OS>
A structure of a CAC (Cloud-Aligned Composite) -OS that can be used for the transistor disclosed in one embodiment of the present invention is described below.

  The CAC-OS is one structure of a material in which elements forming a metal oxide are unevenly distributed with a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or the vicinity thereof. In the following, in the metal oxide, one or more metal elements are unevenly distributed, and the region having the metal element has a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or the vicinity thereof. The state mixed with is also referred to as a mosaic or patch.

  Note that the metal oxide preferably contains at least indium. In particular, it is preferable to contain indium and zinc. In addition, aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc. One kind selected from the above or a plurality of kinds may be included.

For example, a CAC-OS in In-Ga-Zn oxide (In-Ga-Zn oxide among CAC-OSs may be referred to as CAC-IGZO in particular) is an indium oxide (hereinafter referred to as InO). _X1 (X1 is greater real than 0) and.), or indium zinc oxide _{(hereinafter, in X2 Zn Y2 O Z2 (} X2, Y2, and Z2 is larger real than 0) and a.), gallium An oxide (hereinafter referred to as GaO _X3 (X3 is a real number greater than 0)) or a gallium zinc oxide (hereinafter referred to as Ga _X4 Zn _Y4 O _Z4 (where X4, Y4, and Z4 are greater than 0)) to.) and the like, the material becomes mosaic by separate into, mosaic _{InO X1} or _in X2 _Zn Y2 _{O Z2,} is a configuration in which uniformly distributed in the film (hereinafter Also referred to as a cloud-like.) A.

That, CAC-OS includes a region _{GaO X3} is the main _component, and In _{X2 Zn} Y2 _{O Z2,} or _{InO X1} is the main component region is a composite metal oxide having a structure that is mixed. Note that in this specification, for example, the first region indicates that the atomic ratio of In to the element M in the first region is larger than the atomic ratio of In to the element M in the second region. It is assumed that the concentration of In is higher than that in the second region.

Note that IGZO is a common name and may refer to one compound of In, Ga, Zn, and O. As a typical example, InGaO ₃ (ZnO) _m1 (m1 is a natural number) or In _{(1 + x0)} Ga _(1-x0) O ₃ (ZnO) _m0 (−1 ≦ x0 ≦ 1, m0 is an arbitrary number) A crystalline compound may be mentioned.

  The crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. The CAAC structure is a crystal structure in which a plurality of IGZO nanocrystals have c-axis orientation and are connected without being oriented in the ab plane.

  On the other hand, CAC-OS relates to a material structure of a metal oxide. CAC-OS refers to a region observed in the form of nanoparticles mainly composed of Ga in a material structure including In, Ga, Zn and O, and nanoparticles mainly composed of In. The region observed in a shape is a configuration in which the regions are randomly dispersed in a mosaic shape. Therefore, in the CAC-OS, the crystal structure is a secondary element.

  Note that the CAC-OS does not include a stacked structure of two or more kinds of films having different compositions. For example, a structure composed of two layers of a film mainly containing In and a film mainly containing Ga is not included.

Incidentally, a region _{GaO X3} is the main _component, and In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component region, in some cases clear boundary can not be observed.

  In place of gallium, aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium are selected. In the case where one or a plurality of types are included, the CAC-OS includes a region that is observed in a part of a nanoparticle mainly including the metal element and a nanoparticle mainly including In. The region observed in the form of particles refers to a configuration in which each region is randomly dispersed in a mosaic shape.

  The CAC-OS can be formed by a sputtering method under a condition where the substrate is not intentionally heated, for example. In the case where a CAC-OS is formed by a sputtering method, any one or more selected from an inert gas (typically argon), an oxygen gas, and a nitrogen gas may be used as a deposition gas. Good. Further, the flow rate ratio of the oxygen gas to the total flow rate of the deposition gas during film formation is preferably as low as possible. .

  The CAC-OS is characterized in that no clear peak is observed when it is measured using a θ / 2θ scan by the out-of-plane method, which is one of the X-ray diffraction (XRD) measurement methods. Have. That is, it can be seen from X-ray diffraction that no orientation in the ab plane direction and c-axis direction of the measurement region is observed.

  In addition, in the CAC-OS, an electron diffraction pattern obtained by irradiating an electron beam with a probe diameter of 1 nm (also referred to as a nanobeam electron beam) has a ring-like region having a high luminance and a plurality of bright regions in the ring region. A point is observed. Therefore, it can be seen from the electron beam diffraction pattern that the crystal structure of the CAC-OS has an nc (nano-crystal) structure having no orientation in the planar direction and the cross-sectional direction.

Further, for example, in a CAC-OS in an In—Ga—Zn oxide, a region in which GaO _X3 is a main component is obtained by EDX mapping obtained by using energy dispersive X-ray spectroscopy (EDX). It can be confirmed that a region in which In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component is unevenly distributed and mixed.

The CAC-OS has a structure different from that of the IGZO compound in which the metal element is uniformly distributed, and has a property different from that of the IGZO compound. That is, in the CAC-OS, a region in which GaO _X3 or the like is a main component and a region in which In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component are phase-separated from each other, and a region in which each element is a main component. Has a mosaic structure.

Here, the region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is a region having higher conductivity than a region containing GaO _X3 or the like as a main component. _That, In _{X2 Zn} Y2 _{O Z2} or _{InO X1,} is an area which is the main component, by carriers flow, conductive metal oxide is expressed. Accordingly, a region where In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component is distributed in a cloud shape in the metal oxide, so that high field-effect mobility (μ) can be realized.

On the other hand, areas such as _{GaO X3} is the main _component, as compared to the In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component area, it is highly regions insulating. That is, since the region mainly composed of GaO _X3 or the like is distributed in the metal oxide, a leakage current can be suppressed and a good switching operation can be realized.

Therefore, when CAC-OS is used for a semiconductor element, the insulating property caused by GaO _{X3 and the} like and the conductivity caused by In _X2 Zn _Y2 O _Z2 or InO _X1 act in a complementary manner, resulting in high An on-current (I _on ) and high field effect mobility (μ) can be realized.

  In addition, a semiconductor element using a CAC-OS has high reliability. Therefore, the CAC-OS is optimal for various semiconductor devices including a display.

  Alternatively, silicon is preferably used for a semiconductor in which a channel of the transistor is formed. Although amorphous silicon may be used as silicon, it is particularly preferable to use silicon having crystallinity. For example, microcrystalline silicon, polycrystalline silicon, single crystal silicon, or the like is preferably used. In particular, polycrystalline silicon can be formed at a lower temperature than single crystal silicon, and has higher field effect mobility and higher reliability than amorphous silicon. By applying such a polycrystalline semiconductor to a pixel, the aperture ratio of the pixel can be improved. Even in the case of a display portion with extremely high definition, the gate driver circuit and the source driver circuit can be formed over the same substrate as the pixel, and the number of components included in the electronic device can be reduced.

  The bottom-gate transistor described in this embodiment is preferable because the number of manufacturing steps can be reduced. At this time, since amorphous silicon can be used at a lower temperature than polycrystalline silicon, it is possible to use a material having low heat resistance as a material for wiring, electrodes, and substrates below the semiconductor layer. Can widen the choice of materials. For example, a glass substrate having an extremely large area can be suitably used. On the other hand, a top-gate transistor is preferable because an impurity region can be easily formed in a self-aligned manner and variation in characteristics can be reduced. At this time, it is particularly suitable when polycrystalline silicon, single crystal silicon or the like is used.

[Conductive layer]
In addition to the gate, source, and drain of a transistor, materials that can be used for conductive layers such as various wirings and electrodes that constitute a display device include aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, A metal such as tantalum or tungsten, or an alloy containing the same as a main component can be given. A film containing any of these materials can be used as a single layer or a stacked structure. For example, a single layer structure of an aluminum film containing silicon, a two layer structure in which an aluminum film is stacked on a titanium film, a two layer structure in which an aluminum film is stacked on a tungsten film, and a copper film on a copper-magnesium-aluminum alloy film Two-layer structure to stack, two-layer structure to stack copper film on titanium film, two-layer structure to stack copper film on tungsten film, titanium film or titanium nitride film, and aluminum film or copper film on top of it A three-layer structure for forming a titanium film or a titanium nitride film thereon, a molybdenum film or a molybdenum nitride film, and an aluminum film or a copper film stacked thereon, and a molybdenum film or a There is a three-layer structure for forming a molybdenum nitride film. Note that an oxide such as indium oxide, tin oxide, or zinc oxide may be used. Further, it is preferable to use copper containing manganese because the controllability of the shape by etching is increased.

  As the light-transmitting conductive material, conductive oxide such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zinc oxide to which gallium is added, or graphene can be used. Alternatively, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or an alloy material containing the metal material can be used. Alternatively, a nitride (eg, titanium nitride) of the metal material may be used. Note that in the case where a metal material or an alloy material (or a nitride thereof) is used, it may be thin enough to have a light-transmitting property. In addition, a stacked film of the above materials can be used as a conductive layer. For example, it is preferable to use a laminated film of an alloy of silver and magnesium and indium tin oxide because the conductivity can be increased. These can also be used for conductive layers such as various wirings and electrodes constituting the display device and conductive layers (conductive layers functioning as pixel electrodes and common electrodes) included in the display element.

[Insulation layer]
Insulating materials that can be used for each insulating layer include, for example, resins such as acrylic and epoxy, resins having a siloxane bond, and inorganic insulation such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide. Materials can also be used.

  The light-emitting element is preferably provided between a pair of insulating films with low water permeability. Thereby, impurities such as water can be prevented from entering the light emitting element, and a decrease in reliability of the apparatus can be suppressed.

  Examples of the low water-permeable insulating film include a film containing nitrogen and silicon such as a silicon nitride film and a silicon nitride oxide film, and a film containing nitrogen and aluminum such as an aluminum nitride film. Alternatively, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

For example, the water vapor transmission rate of an insulating film with low water permeability is 1 × 10 ⁻⁵ [g / (m ² · day)] or less, preferably 1 × 10 ⁻⁶ [g / (m ² · day)] or less, More preferably, it is 1 × 10 ⁻⁷ [g / (m ² · day)] or less, and further preferably 1 × 10 ⁻⁸ [g / (m ² · day)] or less.

[Liquid crystal element]
As the liquid crystal element, for example, a liquid crystal element to which a vertical alignment (VA: Vertical Alignment) mode is applied can be used. As the vertical alignment mode, an MVA (Multi-Domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, an ASV (Advanced Super View) mode, or the like can be used.

  As the liquid crystal element, liquid crystal elements to which various modes are applied can be used. For example, in addition to the VA mode, a TN (Twisted Nematic) mode, an IPS (In-Plane-Switching) mode, an FFS (Fringe Field Switching) mode, an ASM (Axially Symmetrical Aligned Micro-cell) mode, , A liquid crystal element to which an FLC (Ferroelectric Liquid Crystal) mode, an AFLC (Anti Ferroelectric Liquid Crystal) mode, an ECB (Electrically Controlled Birefringence) mode, a guest host mode, or the like can be used. .

  Note that a liquid crystal element is an element that controls transmission or non-transmission of light by an optical modulation action of liquid crystal. Note that the optical modulation action of the liquid crystal is controlled by an electric field applied to the liquid crystal (including a horizontal electric field, a vertical electric field, or an oblique electric field). As the liquid crystal used for the liquid crystal element, a thermotropic liquid crystal, a low molecular liquid crystal, a polymer liquid crystal, a polymer dispersed liquid crystal (PDLC), a polymer network liquid crystal (PNLC), Ferroelectric liquid crystals, antiferroelectric liquid crystals, and the like can be used. These liquid crystal materials exhibit a cholesteric phase, a smectic phase, a cubic phase, a chiral nematic phase, an isotropic phase, and the like depending on conditions.

  Further, as the liquid crystal material, either a positive type liquid crystal or a negative type liquid crystal may be used, and an optimal liquid crystal material may be used according to an applied mode or design.

  An alignment film can be provided to control the alignment of the liquid crystal. Note that in the case of employing a horizontal electric field mode, liquid crystal exhibiting a blue phase for which an alignment film is unnecessary may be used. The blue phase is one of the liquid crystal phases. When the temperature of the cholesteric liquid crystal is increased, the blue phase appears immediately before the transition from the cholesteric phase to the isotropic phase. Since the blue phase appears only in a narrow temperature range, a liquid crystal composition mixed with several percent by weight or more of a chiral agent is used for the liquid crystal layer in order to improve the temperature range. A liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent has a short response speed and is optically isotropic. In addition, a liquid crystal composition including a liquid crystal exhibiting a blue phase and a chiral agent does not require alignment treatment and has a small viewing angle dependency. Further, since it is not necessary to provide an alignment film, a rubbing process is not required, so that electrostatic breakdown caused by the rubbing process can be prevented, and defects or breakage of the liquid crystal display device during the manufacturing process can be reduced. .

  As the liquid crystal element, a transmissive liquid crystal element, a reflective liquid crystal element, a transflective liquid crystal element, or the like can be used.

  In one embodiment of the present invention, a reflective liquid crystal element can be used.

  In the case of using a transmissive or transflective liquid crystal element, two polarizing plates are provided so as to sandwich a pair of substrates. A backlight is provided outside the polarizing plate. The backlight may be a direct type backlight or an edge light type backlight. It is preferable to use a direct-type backlight including an LED (Light Emitting Diode) because local dimming is facilitated and contrast can be increased. An edge light type backlight is preferably used because the thickness of the module including the backlight can be reduced.

  In the case of using a reflective liquid crystal element, a polarizing plate is provided on the display surface side. Separately from this, it is preferable to arrange a light diffusing plate on the display surface side because the visibility can be improved.

[Light emitting element]
As the light-emitting element, an element capable of self-emission can be used, and an element whose luminance is controlled by current or voltage is included in its category. For example, a light emitting diode (LED), an organic EL element, an inorganic EL element, or the like can be used.

  Light emitting elements include a top emission type, a bottom emission type, and a dual emission type. A conductive film that transmits visible light is used for the electrode from which light is extracted. In addition, a conductive film that reflects visible light is preferably used for the electrode from which light is not extracted.

  In one embodiment of the present invention, a bottom emission light-emitting element can be used.

  The EL layer has at least a light emitting layer. The EL layer is a layer other than the light-emitting layer, such as a substance having a high hole injection property, a substance having a high hole transport property, a hole blocking material, a substance having a high electron transport property, a substance having a high electron injection property, or a bipolar property. A layer including a substance (a substance having a high electron transporting property and a high hole transporting property) and the like may be further included.

  Either a low molecular compound or a high molecular compound can be used for the EL layer, and an inorganic compound may be included. The layers constituting the EL layer can be formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an ink jet method, or a coating method.

  When a voltage higher than the threshold voltage of the light emitting element is applied between the cathode and the anode, holes are injected into the EL layer from the anode side and electrons are injected from the cathode side. The injected electrons and holes are recombined in the EL layer, and the light-emitting substance contained in the EL layer emits light.

  In the case where a white light-emitting element is used as the light-emitting element, the EL layer preferably includes two or more light-emitting substances. For example, white light emission can be obtained by selecting the light emitting material so that the light emission of each of the two or more light emitting materials has a complementary color relationship. For example, a light emitting material that emits light such as R (red), G (green), B (blue), Y (yellow), and O (orange), or spectral components of two or more colors of R, G, and B It is preferable that 2 or more are included among the luminescent substances which show light emission containing. In addition, it is preferable to apply a light-emitting element whose emission spectrum from the light-emitting element has two or more peaks within a wavelength range of visible light (for example, 350 nm to 750 nm). The emission spectrum of the material having a peak in the yellow wavelength region is preferably a material having spectral components in the green and red wavelength regions.

  The EL layer preferably has a structure in which a light-emitting layer including a light-emitting material that emits one color and a light-emitting layer including a light-emitting material that emits another color are stacked. For example, the plurality of light emitting layers in the EL layer may be stacked in contact with each other, or may be stacked through a region not including any light emitting material. For example, a region including the same material (for example, a host material or an assist material) as the fluorescent light emitting layer or the phosphorescent light emitting layer and not including any light emitting material is provided between the fluorescent light emitting layer and the phosphorescent light emitting layer. Also good. This facilitates the production of the light emitting element and reduces the driving voltage.

  The light-emitting element may be a single element having one EL layer or a tandem element in which a plurality of EL layers are stacked with a charge generation layer interposed therebetween.

  The conductive film that transmits visible light can be formed using, for example, indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide to which gallium is added, or the like. In addition, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, an alloy including these metal materials, or a nitride of these metal materials (for example, Titanium nitride) can also be used by forming it thin enough to have translucency. In addition, a stacked film of the above materials can be used as a conductive layer. For example, it is preferable to use a stacked film of an alloy of silver and magnesium and indium tin oxide because the conductivity can be increased. Further, graphene or the like may be used.

  For the conductive film that reflects visible light, for example, a metal material such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or an alloy including these metal materials is used. Can do. In addition, lanthanum, neodymium, germanium, or the like may be added to the metal material or alloy. Alternatively, titanium, nickel, or neodymium and an alloy containing aluminum (aluminum alloy) may be used. Alternatively, an alloy containing copper, palladium, magnesium, and silver may be used. An alloy containing silver and copper is preferable because of its high heat resistance. Furthermore, oxidation can be suppressed by stacking a metal film or a metal oxide film in contact with the aluminum film or the aluminum alloy film. Examples of materials for such metal films and metal oxide films include titanium and titanium oxide. Alternatively, the conductive film that transmits visible light and a film made of a metal material may be stacked. For example, a laminated film of silver and indium tin oxide, a laminated film of an alloy of silver and magnesium and indium tin oxide, or the like can be used.

  The electrodes may be formed using a vapor deposition method or a sputtering method, respectively. In addition, it can be formed using a discharge method such as an inkjet method, a printing method such as a screen printing method, or a plating method.

  Note that the above-described light-emitting layer and a layer containing a substance having a high hole-injecting property, a substance having a high hole-transporting property, a substance having a high electron-transporting property, a substance having a high electron-injecting property, a bipolar substance, Each may have an inorganic compound such as a quantum dot or a polymer compound (oligomer, dendrimer, polymer, etc.). For example, a quantum dot can be used for a light emitting layer to function as a light emitting material.

  As the quantum dot material, a colloidal quantum dot material, an alloy type quantum dot material, a core / shell type quantum dot material, a core type quantum dot material, or the like can be used. Alternatively, a material including an element group of Group 12 and Group 16, Group 13 and Group 15, or Group 14 and Group 16 may be used. Alternatively, a quantum dot material containing an element such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, or aluminum may be used.

[Adhesive layer]
As the adhesive layer, various curable adhesives such as an ultraviolet curable photocurable adhesive, a reactive curable adhesive, a thermosetting adhesive, and an anaerobic adhesive can be used. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenol resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, EVA (ethylene vinyl acetate) resins, and the like. In particular, a material with low moisture permeability such as an epoxy resin is preferable. Alternatively, a two-component mixed resin may be used. Further, an adhesive sheet or the like may be used.

  Further, the resin may contain a desiccant. For example, a substance that adsorbs moisture by chemical adsorption, such as an alkaline earth metal oxide (such as calcium oxide or barium oxide), can be used. Alternatively, a substance that adsorbs moisture by physical adsorption, such as zeolite or silica gel, may be used. The inclusion of a desiccant is preferable because impurities such as moisture can be prevented from entering the element and the reliability of the display panel is improved.

  In addition, light extraction efficiency can be improved by mixing a filler having a high refractive index or a light scattering member with the resin. For example, titanium oxide, barium oxide, zeolite, zirconium, or the like can be used.

(Connection layer)
As the connection layer, an anisotropic conductive film (ACF: Anisotropic Conductive Film), an anisotropic conductive paste (ACP: Anisotropic Conductive Paste), or the like can be used.

(Colored layer)
Examples of materials that can be used for the colored layer include metal materials, resin materials, resin materials containing pigments or dyes, and the like.

[Light shielding layer]
Examples of the material that can be used for the light-shielding layer include carbon black, titanium black, metal, metal oxide, and composite oxide containing a solid solution of a plurality of metal oxides. The light shielding layer may be a film containing a resin material or a thin film of an inorganic material such as a metal. Alternatively, a stacked film of a film containing a material for the colored layer can be used for the light shielding layer. For example, a stacked structure of a film including a material used for a colored layer that transmits light of a certain color and a film including a material used for a colored layer that transmits light of another color can be used. It is preferable to use a common material for the coloring layer and the light-shielding layer because the apparatus can be shared and the process can be simplified.

  The above is the description of each component.

  This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 2)
In this embodiment, as an example of a display device of one embodiment of the present invention, both a reflective liquid crystal element and a light-emitting element are provided, and a light-emitting mode, a reflective mode, and a hybrid mode display in which these are performed simultaneously are performed. An example of a display device (display panel) that can be used will be described. Such a display panel can also be called ER-Hybrid Display (Emission and Reflection Hybrid Display or Emission / Reflection Hybrid Display).

  The display device of one embodiment of the present invention is a display device in which a first display element that reflects visible light and a second display element that emits visible light are mixed.

  The display device has a function of displaying an image with one or both of first light reflected by the first display element and second light emitted by the second display element. Alternatively, the display device functions to express gradation by controlling the amount of first light reflected by the first display element and the amount of second light emitted by the second display element, respectively. Have

  In addition, the display device controls the first pixel that expresses gradation by controlling the amount of reflected light from the first display element, and the gradation by controlling the amount of light emitted from the second display element. A structure including the second pixel to be expressed is preferable. A plurality of first pixels and second pixels are arranged in a matrix, for example, and constitute a display unit.

  The first pixel and the second pixel are preferably arranged in the display area at the same pitch. At this time, the adjacent first pixel and second pixel can be collectively referred to as a pixel unit.

  Furthermore, it is preferable that the first pixel and the second pixel are arranged in a mixed manner in the display region of the display device. Thereby, as will be described later, both the image displayed only with the plurality of first pixels, the image displayed only with the plurality of second pixels, and the plurality of first pixels and the plurality of second pixels. Each of the images displayed in can be displayed in the same display area.

  As the first display element included in the first pixel, an element that reflects external light for display can be used. Since such an element does not have a light source, power consumption during display can be extremely reduced.

  As the first display element, a reflective liquid crystal element can be typically used. Alternatively, as the first display element, in addition to a shutter-type MEMS (Micro Electro Mechanical Systems) element, an optical interference-type MEMS element, a microcapsule method, an electrophoresis method, an electrowetting method, an electronic powder fluid (registered trademark) An element to which a method or the like is applied can be used.

  In addition, the second display element included in the second pixel includes a light source, and an element that performs display using light from the light source can be used. In particular, an electroluminescent element that can extract light emitted from a light-emitting substance by applying an electric field is preferably used. The light emitted from such a pixel is not affected by the brightness or chromaticity of the light, and therefore has high color reproducibility (wide color gamut) and high contrast, that is, vivid display. be able to.

  As the second display element, for example, a self-luminous light emitting element such as an OLED (Organic Light Emitting Diode), an LED (Light Emitting Diode), a QLED (Quantum-Dot Light Emitting Diode), or a semiconductor laser can be used. Alternatively, as the display element included in the second pixel, a combination of a backlight that is a light source and a transmissive liquid crystal element that controls the amount of light transmitted through the backlight may be used.

  The first pixel can include a sub-pixel that exhibits, for example, white (W), or a sub-pixel that exhibits three colors of light, for example, red (R), green (G), and blue (B). . Similarly, the second pixel has a sub-pixel that exhibits, for example, white (W), or a sub-pixel that exhibits light of three colors, for example, red (R), green (G), and blue (B). can do. Note that the subpixels included in each of the first pixel and the second pixel may have four or more colors. As the number of subpixels increases, power consumption can be reduced and color reproducibility can be improved.

  As an example of such a display panel, there is a configuration in which a liquid crystal element including an electrode that reflects visible light and a light emitting element are stacked. At this time, it is preferable that the electrode that reflects visible light has an opening, and the opening and the light-emitting element are overlaid. Thereby, in the light emission mode, it can drive so that the light from a light emitting element may be inject | emitted through the said opening. In addition, in a plan view, the size of a pixel including both the liquid crystal element and the light emitting element can be reduced by stacking and arranging the liquid crystal element and the light emitting element side by side. A higher definition display device can be realized.

  Furthermore, it is preferable that the transistor for driving the liquid crystal element and the transistor for forming the light emitting element are individually provided. Thereby, a liquid crystal element and a light emitting element can be driven independently, respectively.

  Here, a transistor in which an oxide semiconductor is used and an off-state current is extremely low is preferably used for a pixel circuit that drives a liquid crystal element. Alternatively, a memory element may be applied to the pixel circuit. This makes it possible to maintain gradation even when the writing operation to the pixel is stopped when a still image is displayed using the liquid crystal element. That is, display can be maintained even if the frame rate is extremely small. Thereby, a display with extremely low power consumption can be performed.

  One embodiment of the present invention is a first mode in which an image is displayed with a reflective element, a second mode in which an image is displayed with a light emitting element, and a third mode in which an image is displayed with a reflective element and the light emitting element. Can be switched. In particular, the third mode can also be called a hybrid mode.

  The first mode is a mode for displaying an image using reflected light from a reflective element. The first mode is a driving mode with extremely low power consumption because no light source is required. For example, it is effective when the illuminance of outside light is sufficiently high and the outside light is white light or light in the vicinity thereof. The first mode is a display mode suitable for displaying character information such as books and documents. In addition, since the reflected light is used, it is possible to perform display that is kind to the eyes, and the effect that the eyes are less tired is achieved.

  The second mode is a mode in which an image is displayed using light emitted from the light emitting element. Therefore, an extremely vivid display (high contrast and high color reproducibility) can be performed regardless of the illuminance and chromaticity of external light. For example, it is effective when the illuminance of outside light is extremely small, such as at night or in a dark room. Further, when the outside light is dark, the user may feel dazzled when performing bright display. In order to prevent this, it is preferable to perform display with reduced luminance in the second mode. Thereby, in addition to suppressing glare, power consumption can also be reduced. The second mode is a mode suitable for displaying a vivid image or a smooth moving image.

  The third mode is a mode in which display is performed using both reflected light from a reflective element and light emitted from a light emitting element. Specifically, driving is performed so as to express one color by mixing light emitted by the reflective element and light emitted by the light emitting element. While displaying more vividly than in the first mode, it is possible to suppress power consumption as compared with the second mode. For example, it is effective when the illuminance of outside light is relatively low, such as under room lighting or in the morning or evening hours, or when the chromaticity of outside light is not white. Further, by using light in which reflected light and light emission are mixed, it is possible to display an image that makes it feel as if the user is looking at a painting.

<Specific examples of the first to third modes>
Here, a specific example in the case of using the first to third modes described above will be described with reference to FIGS.

  Hereinafter, a case where the first to third modes are automatically switched according to the illuminance will be described. In addition, when switching automatically according to illumination intensity, an illumination sensor etc. can be provided in a display apparatus, for example, and a display mode can be switched based on the information from the said illumination intensity sensor.

  18A, 18B, and 18C are schematic diagrams of pixels for explaining display modes that can be taken by the display device of this embodiment.

  18A, 18B, and 18C, the first display element 501, the second display element 502, the opening 503, the reflected light 504 reflected from the first display element 501, and the second display The transmitted light 505 emitted from the element 502 through the opening 503 is clearly shown. 18A is a diagram for explaining the first mode, FIG. 18B is a diagram for explaining the second mode, and FIG. 18C is a diagram for explaining the third mode. It is.

  18A, 18B, and 18C, a reflective liquid crystal element is used as the first display element 501, and a transmissive liquid crystal element is used as the second display element 502.

  In the first mode illustrated in FIG. 18A, grayscale display can be performed by adjusting the intensity of reflected light by driving a reflective liquid crystal element which is the first display element 501. For example, as shown in FIG. 19A, gradation display is performed by adjusting the intensity of reflected light 504 with a liquid crystal layer using a reflective electrode included in a reflective liquid crystal element which is the first display element 501. be able to.

  In the second mode illustrated in FIG. 18B, grayscale display can be performed by adjusting the intensity of transmitted light by driving a transmissive liquid crystal element which is the second display element 502. Note that light emitted from the second display element 502 passes through the opening 503 and is extracted to the outside as transmitted light 505.

  A third mode illustrated in FIG. 18C is a display mode in which the above-described first mode and the second mode are combined. For example, the reflective electrode included in the reflective liquid crystal element which is the first display element 501 is used to perform gradation display by adjusting the intensity of the reflected light 504 with the liquid crystal layer. Further, the intensity of the transmitted light of the transmissive liquid crystal element, which is the second display element 502, in this case, the intensity of the transmitted light 505 is adjusted in the same period as the period during which the first display element 501 is driven. Displays the key.

<State transition in first to third modes>
Next, state transition in the first to third modes will be described with reference to FIG. FIG. 4D is a state transition diagram of the first mode, the second mode, and the third mode. State C1 shown in FIG. 18D corresponds to the first mode, state C2 corresponds to the second mode, and state C3 corresponds to the third mode.

  As shown in FIG. 18D, from the state C1 to the state C3, a display mode in any state can be taken in accordance with the illuminance. For example, when the illuminance is high, such as outdoors, the state C1 can be taken. In addition, when the illuminance is low, such as when moving from outdoors to indoors, the state changes from state C1 to state C2. Further, when the illuminance is low even outdoors, and the gradation display by reflected light is not sufficient, the state C2 is changed to the state C3. Of course, a transition from state C3 to state C1, a transition from state C1 to state C3, a transition from state C3 to state C2, or a transition from state C2 to state C1 also occurs.

  In FIG. 18D, the sun symbol is illustrated as the first mode image, the moon symbol is illustrated as the second mode image, and the cloud symbol is illustrated as the third mode image. It is.

  As shown in FIG. 18D, in the state C1 to the state C3, when there is no change in illuminance or when the change in illuminance is small, the state continues without changing to another state. Should be maintained.

  As described above, with the configuration in which the display mode is switched according to the illuminance, it is possible to reduce the frequency of gradation display of a transmissive liquid crystal element that requires a light source such as a backlight with relatively high power consumption. Therefore, power consumption of the display device can be reduced. The display device can further switch the operation mode according to the remaining capacity of the battery, the content to be displayed, or the illuminance of the surrounding environment. In the above description, the case where the display mode is automatically switched according to the illuminance is illustrated, but the present invention is not limited to this, and the user may manually switch the display mode.

<Operation mode>
Next, operation modes that can be performed in the first display element will be described with reference to FIGS.

  In the following, a normal operation mode (Normal mode) that operates at a normal frame frequency (typically 60 MHz to 240 MHz or less) and an idling stop (IDS) drive mode that operates at a low frame frequency will be exemplified. To explain.

  Note that the idling stop (IDS) driving mode refers to a driving method in which rewriting of image data is stopped after image data writing processing is executed. Once the image data is written and then the interval until the next image data is written is extended, the power consumption required for writing the image data during that time can be reduced. The idling stop (IDS) drive mode can be set to a frame frequency about 1/100 to 1/10 of the normal operation mode, for example.

FIGS. 19A, 19B, and 19C are a circuit diagram and a timing chart for explaining the normal drive mode and the idling stop (IDS) drive mode. Note that FIG. 19A clearly shows a first display element 501 (here, a reflective liquid crystal element) and a pixel circuit 506 electrically connected to the first display element 501. In the pixel circuit 506 illustrated in FIG. 19A, the signal line SL, the gate line GL, the transistor M1 connected to the signal line SL and the gate line GL, and the capacitor Cs _LC connected to the transistor M1 Is illustrated.

  As the transistor M1, a transistor including a metal oxide in a semiconductor layer is preferably used. When the metal oxide has at least one of an amplifying function, a rectifying function, and a switching function, the metal oxide is referred to as a metal oxide semiconductor or an oxide semiconductor, or OS for short. be able to. Hereinafter, a transistor including an oxide semiconductor (OS transistor) will be described as a typical example of a transistor. Since the OS transistor has a very low leakage current (off-state current) in a non-conduction state, electric charge can be held in the pixel electrode of the liquid crystal element by making the OS transistor non-conduction.

Incidentally, in the circuit diagram shown in FIG. 19 (A), the liquid crystal element LC is the leak path of the data _{D 1.} Therefore, in order to appropriately perform idling / stop driving, the resistivity of the liquid crystal element LC is preferably set to 1.0 × 10 ¹⁴ Ω · cm or more.

  Note that an In—Ga—Zn oxide, an In—Zn oxide, or the like can be preferably used for the channel region of the OS transistor, for example. As the In—Ga—Zn oxide, a composition in the vicinity of In: Ga: Zn = 4: 2: 4.1 [atomic ratio] can be typically used.

FIG. 19B is a timing chart showing waveforms of signals supplied to the signal line SL and the gate line GL in the normal drive mode. In the normal drive mode, it operates at a normal frame frequency (for example, 60 Hz). When one frame period is represented by periods T ₁ to T ₃ , an operation of applying a scanning signal to the gate line GL and writing data D ₁ from the signal line SL in each frame period is performed. This operation is the same even when writing the same data D ₁ in the period T ₁ to T ₃ or writing different data.

On the other hand, FIG. 19C is a timing chart showing waveforms of signals supplied to the signal line SL and the gate line GL in the idling stop (IDS) driving mode. The idling stop (IDS) drive operates at a low frame frequency (for example, 1 Hz). Represents one frame period in the period T _1, representing the period T _W a write period of data _therein, the data retention period in the period T _RET. Idling stop (IDS) drive mode, it provides a scan signal to the gate line GL in a period _{T W,} write data _{D 1} of the signal line SL, and a gate line GL is fixed to the low level of the voltage in the period _{T RET,} transistor performs an operation of holding temporarily the data D ₁ is written M1 as a non-conductive state. In addition, what is necessary is just to set it as 0.1 Hz or more and less than 60 Hz as a low-speed frame frequency, for example.

  The idling stop (IDS) drive mode is effective because it can further reduce power consumption by combining with the first mode or the third mode described above.

  As described above, the display device of this embodiment can perform display by switching the first mode to the third mode. Therefore, it is possible to realize a display device or an all-weather display device that is highly visible and convenient regardless of the surrounding brightness.

  In addition, the display device of this embodiment preferably includes a plurality of first pixels each including a first display element and a plurality of second pixels each including a second display element. In addition, the first pixel and the second pixel are preferably arranged in a matrix.

  Each of the first pixel and the second pixel can include one or more subpixels. For example, the pixel has a configuration having one subpixel (white (W), etc.), a configuration having three subpixels (red (R), green (G), and blue (B), etc.), Alternatively, a configuration having four subpixels (red (R), green (G), blue (B), white (W), or red (R), green (G), blue (B), Yellow (Y) and the like can be applied. Note that the color elements included in the first pixel and the second pixel are not limited to the above, and cyan (C), magenta (M), and the like may be combined as necessary.

  In the display device of this embodiment, both the first pixel and the second pixel can perform full color display. Alternatively, the display device in this embodiment can have a structure in which the first pixel performs monochrome display or grayscale display, and the second pixel performs full color display. The monochrome display or grayscale display using the first pixel is suitable for displaying information that does not require color display, such as document information.

  This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 3)
In this embodiment, electronic devices to which the display device of one embodiment of the present invention can be applied will be described.

  The display device of one embodiment of the present invention can achieve high visibility regardless of the intensity of external light. Therefore, it can be suitably used for portable electronic devices, wearable electronic devices (wearable devices), electronic book terminals, television devices, digital signage, and the like.

  20A and 20B show an example of the portable information terminal 800. FIG. The portable information terminal 800 includes a housing 801, a housing 802, a display portion 803, a display portion 804, a hinge portion 805, and the like.

  The housing 801 and the housing 802 are connected by a hinge portion 805. The portable information terminal 800 can open the housing 801 and the housing 802 as illustrated in FIG. 20B from the folded state as illustrated in FIG.

  For example, document information can be displayed on the display portion 803 and the display portion 804 and can be used as an electronic book terminal. In addition, still images and moving images can be displayed on the display portion 803 and the display portion 804.

  Thus, since the portable information terminal 800 can be folded when being carried, it is excellent in versatility.

  Note that the housing 801 and the housing 802 may include a power button, an operation button, an external connection port, a speaker, a microphone, and the like.

  FIG. 20C illustrates an example of a portable information terminal. A portable information terminal 810 illustrated in FIG. 20C includes a housing 811, a display portion 812, operation buttons 813, an external connection port 814, a speaker 815, a microphone 816, a camera 817, and the like.

  The display portion 812 includes the display device of one embodiment of the present invention.

  The portable information terminal 810 includes a touch sensor in the display unit 812. Any operation such as making a call or inputting characters can be performed by touching the display portion 812 with a finger or a stylus.

  Further, the operation of the operation button 813 can switch the power ON / OFF operation and the type of image displayed on the display unit 812. For example, the mail creation screen can be switched to the main menu screen.

  Further, by providing a detection device such as a gyro sensor or an acceleration sensor inside the portable information terminal 810, the orientation (portrait or landscape) of the portable information terminal 810 is determined, and the screen display orientation of the display unit 812 is changed. It can be switched automatically. In addition, the screen display orientation can be switched by touching the display portion 812, operating the operation button 813, or inputting voice using the microphone 816.

  The portable information terminal 810 has one or more functions selected from, for example, a telephone, a notebook, an information browsing device, or the like. Specifically, it can be used as a smartphone. The portable information terminal 810 can execute various applications such as mobile phone, electronic mail, text browsing and creation, music playback, video playback, Internet communication, and games.

  FIG. 20D illustrates an example of a camera. The camera 820 includes a housing 821, a display portion 822, operation buttons 823, a shutter button 824, and the like. A removable lens 826 is attached to the camera 820.

  The display portion 822 includes the display device of one embodiment of the present invention.

  Here, the camera 820 is configured such that the lens 826 can be removed from the housing 821 and replaced, but the lens 826 and the housing may be integrated.

  The camera 820 can capture a still image or a moving image by pressing the shutter button 824. In addition, the display portion 822 has a function as a touch panel and can capture an image by touching the display portion 822.

  The camera 820 can be separately attached with a strobe device, a viewfinder, and the like. Alternatively, these may be incorporated in the housing 821.

  FIG. 21A illustrates a television device 830. The television device 830 includes a display portion 831, a housing 832, a speaker 833, and the like. Furthermore, an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like can be provided.

  Further, the television device 830 can be operated by a remote controller 834.

  Examples of broadcast radio waves that can be received by the television device 830 include terrestrial waves and radio waves transmitted from satellites. As broadcast radio waves, there are analog broadcasts, digital broadcasts, etc., and video and audio, or audio-only broadcasts. For example, broadcast radio waves transmitted in a specific frequency band in the UHF band (about 300 MHz to 3 GHz) or the VHF band (30 MHz to 300 MHz) can be received. In addition, for example, by using a plurality of data received in a plurality of frequency bands, the transfer rate can be increased and more information can be obtained. Thereby, an image having a resolution exceeding full high-definition can be displayed on the display unit 831. For example, an image having a resolution of 4K-2K, 8K-4K, 16K-8K, or higher can be displayed.

  In addition, an image to be displayed on the display unit 831 can be displayed using broadcast data transmitted by a data transmission technique via a computer network such as the Internet, a LAN (Local Area Network), or Wi-Fi (Wireless Fidelity: registered trademark). It is good also as composition to generate. At this time, the television device 830 may not have a tuner.

  FIG. 21B shows a digital signage 840 attached to a columnar column 842. The digital signage 840 has a display portion 841.

  As the display portion 841 is wider, the amount of information that can be provided at a time can be increased. In addition, the wider the display portion 841, the easier it is for people to see. For example, the advertising effect of advertisement can be enhanced.

  By applying a touch panel to the display unit 841, not only an image or a moving image is displayed on the display unit 841, but also a user can operate intuitively, which is preferable. In addition, when it is used for providing information such as route information or traffic information, usability can be improved by an intuitive operation.

  FIG. 21C illustrates a laptop personal computer 850. The personal computer 850 includes a display portion 851, a housing 852, a touch pad 853, a connection port 854, and the like.

  The touch pad 853 functions as an input unit such as a pointing device or a pen tablet, and can be operated with a finger, a stylus, or the like.

  In addition, a display element is incorporated in the touch pad 853. As shown in FIG. 21C, by displaying the input key 855 on the surface of the touch pad 853, the touch pad 853 can be used as a keyboard. At this time, when the input key 855 is touched, a vibration module may be incorporated in the touch pad 853 in order to realize tactile sensation by vibration.

  This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

10 display device 10a touch panel 10EL subpixel 10LC subpixel 10p pixel 11a part 11b part 12B conductive layer 12G conductive layer 12R conductive layer 13 conductive layer 14 conductive layer 15b light reflecting layer 15B conductive layer 15G conductive layer 15R conductive layer 16 conductive layer 20eB light 20eG light 20eR light 20rB light 20rG light 20rR light 21 substrate 21a substrate 23 conductive layer 23a conductive layer 23b conductive layer 24 liquid crystal 25 conductive layer 25b conductive layer 26a alignment film 26b alignment film 31 substrate 31a substrate 32 display unit 34 circuit unit 35 wiring 36 FPC
37 IC
38 Diffusion plate 39 Polarizing plate 40 Liquid crystal element 40B Liquid crystal element 40G Liquid crystal element 40R Liquid crystal element 43a Release layer 44a Support substrate 44b Support substrate 46a Adhesive layer 50 Touch sensor panel 50a FPC
52B colored layer 52G colored layer 52R colored layer 54 colored layer 54a colored layer 54b colored layer 60 light emitting element 60B light emitting element 60G light emitting element 60R light emitting element 60W light emitting element 61 conductive layer 62 EL layer 62a EL layer 63 conductive layer 64 insulating layer 70a transistor 70b transistor 70e1 transistor 70e2 transistor 70r transistor 71 conductive layer 72 semiconductor layer 73a conductive layer 73b conductive layer 74 conductive layer 80 connection portion 81 insulating layer 82 insulating layer 83 insulating layer 84 insulating layer 85 insulating layer 86 insulating layer 88 adhesive layer 89 adhesive layer 90e capacitive element 90r capacitive element 91 insulating layer 92 insulating layer 93 insulating layer 94 insulating layer 95 insulating layer 96 insulating layer 97a insulating layer 97b insulating layer 98 insulating layer 110 transistor 110a transistor 110b transistor 110c transistor 1 0d Transistor 111 Conductive layer 112 Semiconductor layer 112a Semiconductor layer 113a Conductive layer 113b Conductive layer 113c Conductive layer 113d Conductive layer 114 Conductive layer 114a Conductive layer 114b Conductive layer 115 Conductive layer 120 Light emitting element 121 Conductive layer 131 Insulating layer 132 Insulating layer 133 Insulating layer 134 Insulating layer 135 Insulating layer 136 Insulating layer 137 Insulating layer 501 Display element 502 Display element 503 Opening 504 Reflected light 505 Transmitted light 506 Pixel circuit 800 Portable information terminal 801 Housing 802 Housing 803 Display unit 804 Display unit 805 Hinge unit 810 Portable information terminal 811 Case 812 Display unit 813 Operation button 814 External connection port 815 Speaker 816 Microphone 817 Camera 820 Camera 821 Case 822 Display unit 823 Operation button 824 Shutter button 826 Lens 830 Television device 831 Display unit 832 Case 833 Speaker 834 Remote control device 840 Digital signage 841 Display unit 842 Pillar 850 Personal computer 851 Display unit 852 Case 853 Touch pad 854 Connection port 855 Input key

Claims (7)

A first electrode and a second electrode arranged side by side in a first direction;
A third electrode and a fourth electrode provided side by side in a second direction intersecting the first direction on a surface different from the first electrode;
Each of the first electrode and the second electrode functions as one electrode of a liquid crystal element,
The third electrode and the fourth electrode each function as one electrode of a light emitting element,
The first electrode and the second electrode have a notch in a portion overlapping with either the third electrode or the fourth electrode.
Display device. Having first to fourth electrodes;
The first electrode and the second electrode each have a function of reflecting visible light, and each function as one electrode of a liquid crystal element,
The third electrode and the fourth electrode each function as one electrode of a light emitting element,
The first electrode and the second electrode each have a strip shape extending in the first direction, and are arranged side by side in a second direction intersecting the first direction,
The third electrode and the fourth electrode are arranged side by side in the first direction,
The first electrode has a first notch at a position overlapping the third electrode,
The second electrode has a second notch at a position overlapping the fourth electrode.
Display device. In claim 1 or claim 2,
Having a first colored layer and a second colored layer;
The first colored layer and the second colored layer each have a strip shape extending in the first direction, and are arranged side by side in the second direction,
The first colored layer has a portion overlapping the first electrode,
The second colored layer has a portion overlapping the second electrode;
Display device. In claim 3,
The first colored layer has a third notch at a position overlapping the third electrode,
The second colored layer has a fourth notch at a position overlapping the fourth electrode,
The light-emitting element having the third electrode and the light-emitting element having the fourth electrode emit light having different colors.
Display device. In claim 3,
The first colored layer has a portion overlapping the first notch and the third electrode,
The second colored layer has a portion overlapping the second notch and the fourth electrode,
The light-emitting element having the third electrode and the light-emitting element having the fourth electrode emit light having the same color.
Display device. In any one of Claims 1 thru | or 5,
Having first to sixth wirings;
The first wiring and the second wiring each function as a first scanning line for driving the liquid crystal element,
The third wiring functions as a first signal line for driving the liquid crystal element,
The fourth wiring functions as a second scanning line for driving the light emitting element,
The fifth wiring and the sixth wiring each function as a second signal line for driving the light emitting element,
The first wiring, the second wiring, and the fourth wiring each extend in the first direction,
The third wiring, the fifth wiring, and the sixth wiring each extend in the second direction;
Display device. In any one of Claims 1 thru | or 5,
Having first to sixth wirings and first to sixth transistors;
The first wiring, the second wiring, and the fourth wiring each extend in the first direction,
The third wiring, the fifth wiring, and the sixth wiring each extend in the second direction,
The first transistor is electrically connected to the first electrode;
The second transistor is electrically connected to the second electrode;
The third transistor is electrically connected to the third electrode through the fourth transistor;
The fifth transistor is electrically connected to the fourth electrode via the sixth transistor;
The first wiring is electrically connected to a gate of the first transistor;
The second wiring is electrically connected to a gate of the second transistor;
The third wiring is electrically connected to one of a source or a drain of the first transistor and one of a source or a drain of the second transistor;
The fourth wiring is electrically connected to a gate of the third transistor and a gate of the fifth transistor;
The fifth wiring is electrically connected to one of a source and a drain of the third transistor;
The sixth wiring is electrically connected to one of a source and a drain of the fifth transistor;
Display device.

Images