Display device and electronic apparatus

Abstract

Provided is a display device having high display quality. Also provided is a display device having high reliability. Further provided is a novel electronic apparatus. This display device comprises: a support having a shape memory alloy; a flexible display; and a heat-generating part. The display device is provided with: a shape memory alloy provided so as to overlap a curved portion of the flexible display; a heat generation unit that heats the shape memory alloy; a temperature sensor that measures the temperature of the heat generation unit; and a rotation angle sensor for detecting the bending angle of a housing. The heat generation unit heats the shape memory alloy to the shape recovery temperature or higher when the rotation angle sensor detects the expansion of the housing.

Description

Display Device and Electronic Device

[0001] One aspect of the present invention relates to a display device and an electronic device equipped therewith. In particular, it relates to a bendable display device.

[0002] Note that one aspect of the present invention is not limited to the above technical field. Specific examples thereof include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), and driving methods thereof.

[0003] Note that in this specification, the term "semiconductor device" refers to all devices that can function by utilizing semiconductor characteristics. A transistor and a semiconductor circuit are one embodiment of a semiconductor device. Furthermore, memory devices, display devices, and electronic devices may include a semiconductor device.

[0004] In recent years, display devices are expected to be applied to various uses. For example, as portable electronic devices, development of smartphones and tablet terminals provided with touch panels is progressing. Display devices used for portable electronic devices and the like are required to be thin, have a narrow frame, and be lightweight, among other properties.

[0005] Since portable electronic devices are lightweight and compact, there is a problem that the size of a display device that can be mounted on such an electronic device is limited. Accordingly, electronic devices (also referred to as foldable devices) employing a display device provided with a flexible display portion (also referred to as a flexible display) have been anticipated. A foldable device is a device that employs a display device whose display surface is deformable. For example, a foldable device that can be folded in half can be bent for downsizing, and can be unfolded for use with a large screen.

[0006] Typical examples of display elements used in display devices capable of having a bent display surface include organic EL (Electro Luminescence, hereinafter referred to as EL) elements, light-emitting devices (also referred to as light-emitting elements) such as LED (Light Emitting Diode, hereinafter referred to as LED) elements, or liquid crystal elements, and the like.

[0007] The basic structure of an organic EL element is a layer containing a light-emitting material between a pair of electrodes. By applying a voltage to this element, light can be obtained from the light-emitting organic compound. Display devices using such organic EL elements do not require a backlight or other light source, thus enabling the realization of thin, lightweight, high-contrast, and low-power display devices. Furthermore, if the substrate on which the organic EL element is mounted is flexible, a flexible display device can be realized.

[0008] For example, Patent Document 1 discloses a flexible light-emitting device to which an organic EL element is applied.

[0009] For example, Patent Document 2 discloses that a mobile device such as a smartphone or tablet is equipped with a flexible display that follows a movable housing.

[0010] Japanese Patent Publication No. 2014-197522 Japanese Patent Publication No. 2016-075884

[0011] Flexible displays used in foldable devices have low mechanical strength, so a support is provided to improve it. However, if the support is repeatedly bent, the curved portion (also called the folding portion) may plastically deform and lose its shape. As a result, the display surface on the support becomes wavy, leading to problems such as uneven light reflection on the display surface and variations in touch sensitivity depending on the location.

[0012] One aspect of the present invention aims to provide a display device with high display quality. Another aspect of the present invention aims to provide a highly reliable display device. Another aspect of the present invention aims to provide a display device with high contrast. Another aspect of the present invention aims to provide a display device with high visibility. Alternatively, one aspect of the present invention aims to provide a novel electronic device.

[0013] Furthermore, the description of these problems does not preclude the existence of other problems. One aspect of the present invention does not necessarily have to solve all of these problems. It is possible to identify other problems separately from the description in the specification, drawings, and claims.

[0014] (1) One aspect of the present invention is a display device comprising a flexible display, a support having a shape memory alloy, and a heating element, wherein the flexible display and the support have a planar region and a curved region when bent, and the support is located between the flexible display and the heating element, and the heating element has a region that overlaps with the curved region.

[0015] (2) In addition, in (1) above, it is preferable that the heating element has the function of heating the shape memory alloy to a temperature above the shape recovery temperature.

[0016] (3) In addition, in (1) above, it is preferable that the curved region of the support contains a shape memory alloy.

[0017] (4) The electronic device also comprises the display device described in (3) above, a first housing and a second housing joined to a planar region of the support, and a third housing joining the first housing and the second housing, wherein the third housing has a first rotating plate rotatably joined to the first housing and a second rotating plate rotatably joined to the second housing.

[0018] (5) In addition, in (4) above, it is preferable that the planar region of the support has a first region joined to the first housing and a second region joined to the second housing, and that the curved region of the support is located between the first region and the second region.

[0019] (6) Alternatively, a display device comprising a flexible display, a shape memory alloy provided so as to overlap with the curved portion of the flexible display, a heating element for heating the shape memory alloy, a temperature sensor for measuring the temperature of the heating element, and a rotation angle sensor for detecting the bending angle of the housing, wherein the heating element has the function of heating the shape memory alloy to a temperature above its shape recovery temperature when the rotation angle sensor detects the unfolding of the housing.

[0020] (7) Or, a display device comprising a flexible display, a shape memory alloy, and a first terminal and a second terminal electrically connected to the shape memory alloy, wherein the flexible display has a planar region and a curved region when bent, the shape memory alloy has a region that overlaps with the curved region, the shape memory alloy has a heating element that generates heat when current is passed between the first terminal and the second terminal, and the heating element of the shape memory alloy has a region that overlaps with the curved region of the flexible display.

[0021] According to one aspect of the present invention, a highly reliable display device with high display quality can be provided. According to one aspect of the present invention, a display device with high contrast can be applied. According to one aspect of the present invention, a display device with high visibility can be provided.

[0022] According to one aspect of the present invention, a highly reliable display device can be provided. A method for operating a display device with high display quality can be provided.

[0023] According to one aspect of the present invention, a novel electronic device can be provided.

[0024] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description, drawings, and claims.

[0025] Figures 1A and 1B show examples of cross-sectional configurations of a display device. Figures 2A, 2B, and 2C are cross-sectional views showing an example of a support. Figures 3A and 3B are graphs showing an example of a stress-strain curve. Figure 4 is a diagram illustrating the configuration of an electronic device according to an embodiment. Figure 5A is a perspective view showing an example of a display device. Figure 5B is a cross-sectional view showing an example of a display device. Figure 6A is a perspective view showing an example of a display device. Figures 6B and 6C are cross-sectional views showing an example of a display device. Figures 7A and 7B are cross-sectional views showing an example of a display device. Figure 8 is a cross-sectional view showing an example of a display device. Figures 9A, 9B, and 9C are cross-sectional views showing an example of a display device. Figure 10A is a perspective view showing an example of a foldable device. Figures 10B and 10C are plan views showing an example of a foldable device. Figure 11 is a perspective view showing an example of a display device. Figure 12 is a flowchart showing an example of how a display device operates. Figure 13 is a flowchart showing an example of how a display device operates. Figure 14 is a perspective view showing an example of a display device. Figures 15A and 15B are cross-sectional views showing an example of a display device. Figure 16 is a cross-sectional view showing an example of a display device. Figures 17A, 17B, and 17C are cross-sectional views showing an example of a display device. Figures 18A and 18B are cross-sectional views showing an example of a display device. Figures 19A, 19B, 19C, 19D, and 19E are cross-sectional views showing an example of a transistor.

[0026] Embodiments will be described in detail with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be construed as being limited to the descriptions of the embodiments shown below.

[0027] In the configuration of the invention described below, the same reference numerals are used in common across different drawings for parts that are identical or have similar functions, and repeated explanations are omitted. In addition, when referring to similar functions, the hatching patterns are the same, and reference numerals may not be assigned.

[0028] The positions, sizes, and ranges of each component shown in the drawings may not represent their actual positions, sizes, and ranges for the sake of ease of understanding. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and ranges disclosed in the drawings.

[0029] In this specification, the ordinal numbers "first," "second," etc., are used for convenience only and do not limit the number of components or the order of components (for example, process order or stacking order). Furthermore, the ordinal numbers used for components in one part of this specification may not be the same as those used for the same components in other parts of this specification or in the claims.

[0030] In this specification and drawings, when the same reference numeral is used for multiple elements, and especially when it is necessary to distinguish them, the reference numeral may be accompanied by an identifying numeral such as "_1", "[n]", or "[m,n]". Furthermore, when describing a common matter for multiple elements with identifying numerals, or when it is not necessary to distinguish them, the identifying numeral may be omitted.

[0031] The words "film" and "layer" can be interchanged depending on the context or situation. For example, the term "conductive layer" can be changed to "conductive film." Or, for example, the term "insulating film" can be changed to "insulating layer."

[0032] A transistor is a type of semiconductor device that can perform functions such as amplifying current or voltage, and switching operations that control conduction or non-conductivity. Transistors as used herein include IGFETs (Insulated Gate Field Effect Transistors) and thin-film transistors (TFTs).

[0033] The functions of "source" and "drain" may be reversed when transistors with different polarities are used, or when the direction of current changes during circuit operation. For this reason, in this specification, the terms "source" and "drain" may be used interchangeably. Furthermore, the names of the source and drain of a transistor can be appropriately rephrased as source terminal and drain terminal, or source electrode and drain electrode, depending on the situation.

[0034] The terms "gate" and "back gate" are interchangeable. Therefore, in this specification, the terms "gate" and "back gate" may be used interchangeably. Furthermore, the names of the gate and back gate of a transistor can be appropriately rephrased as gate electrode and back gate electrode, etc., depending on the context.

[0035] In this specification, "connection" includes, for example, "electrical connection." The term "electrical connection" is sometimes used to define the connection relationship of circuit elements as a physical object. Furthermore, "electrical connection" includes both "direct connection" and "indirect connection." "A and B are directly connected" means that A and B are connected without the use of circuit elements (e.g., transistors, switches, etc.; wiring is not considered a circuit element). On the other hand, "A and B are indirectly connected" means that A and B are connected through one or more circuit elements. A, B, and C (described later) refer to objects such as elements, circuits, wiring, electrodes, terminals, semiconductor layers, and conductive layers.

[0036] In this specification, unless otherwise specified, on-current refers to the drain current (also written as Id) when the transistor is in the ON state (also called the conducting state). Unless otherwise specified, the ON state in an n-channel transistor refers to the state in which the voltage between the gate and source (also written as Vg) is equal to or greater than the threshold voltage (also written as Vth). The ON state in a p-channel transistor refers to the state in which the voltage between the gate and source is less than or equal to the threshold voltage.

[0037] In this specification, unless otherwise specified, off-current refers to the source-drain leakage current when the transistor is in the off state (also called the non-conductive state or cutoff state). Unless otherwise specified, the off state refers to the state in an n-channel transistor where the voltage between the gate and source is lower than the threshold voltage, and in a p-channel transistor where it is higher than the threshold voltage.

[0038] In this specification, "parallel" means a state in which two lines are positioned at an angle within the range of -10 degrees to 10 degrees. Therefore, the case of -5 degrees to 5 degrees is also included. Furthermore, "approximately parallel" means a state in which two lines are positioned at an angle within the range of -30 degrees to 30 degrees. Furthermore, "perpendicular" means a state in which two lines are positioned at an angle within the range of 80 degrees to 100 degrees. Therefore, the case of 85 degrees to 95 degrees is also included. Furthermore, "approximately perpendicular" means a state in which two lines are positioned at an angle within the range of 60 degrees to 120 degrees.

[0039] In this specification, "matching or roughly matching top shapes" means that at least a portion of the contours overlap between stacked layers. For example, this includes cases where the upper and lower layers are processed with the same mask pattern, or partially with the same mask pattern. However, strictly speaking, the contours may not overlap, and the upper layer may be located inside the lower layer, or the upper layer may be located outside the lower layer; in this case, it may also be said that the "matching or roughly matching top shapes" apply. Furthermore, when the top shapes match or roughly match, it can also be said that the "edges match or roughly match," or "the edges are aligned or roughly aligned."

[0040] It should be noted that, in the following, expressions indicating orientations such as "upper" and "lower" are basically used in accordance with the orientation of the drawings. However, for the purpose of facilitating description and other purposes, the orientation meant by "upper" or "lower" in the present specification may not match that in the drawings. For example, when describing the stacking order (or forming order) of a stacked body or the like, even if the surface on which the stacked body is provided in the drawings (such as a surface to be formed, a support surface, an adhesive surface, or a flat surface) is located above the stacked body, it may be expressed that the surface to be formed is at the lower side, and the stacked body is at the upper side.

[0041] It should be noted that in the drawings and the like according to the present specification, arrows indicating the X direction, the Y direction, and the Z direction may be added. In the present specification and the like, the "X direction" is a direction along the X axis, and forward and reverse directions may not be distinguished unless explicitly stated. The same applies to the "Y direction" and the "Z direction". In addition, the X direction, the Y direction, and the Z direction are directions that intersect each other. For example, the X direction, the Y direction, and the Z direction are directions that are orthogonal to each other.

[0042] It should be noted that in the present specification and the like, a tapered shape refers to a shape in which at least a part of the side surface of a structure is provided inclined with respect to the substrate surface or the surface to be formed. For example, when the angle formed by the inclined side surface and the substrate surface or the surface to be formed (hereinafter may be referred to as a taper angle) is less than 90 degrees, the shape is referred to as a forward tapered shape, and when the angle exceeds 90 degrees, the shape is referred to as a reverse tapered shape.

[0043] In the present specification and the like, a device manufactured using a metal mask or FMM (fine metal mask, a high-definition metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in the present specification and the like, a device manufactured without using a metal mask or FMM may be referred to as a device with an MML (metal mask-less) structure.

[0044] In the present specification and the like, a structure in which light-emitting layers are separately formed for light-emitting devices with different emission wavelengths may be referred to as an SBS (Side By Side) structure.

[0045] In this specification, "step break" refers to a division of a layer, film, or electrode due to the shape of the surface on which it is formed (e.g., a step).

[0046] In this specification, holes or electrons may be referred to as "carriers." For example, in a light-emitting device, a hole injection layer or electron injection layer may be called a "carrier injection layer," a hole transport layer or electron transport layer may be called a "carrier transport layer," and a hole blocking layer or electron blocking layer may be called a "carrier blocking layer." It should be noted that the above-mentioned carrier injection layer, carrier transport layer, and carrier blocking layer may not always be clearly distinguishable. Furthermore, a single layer may combine the functions of two or three of the carrier injection layer, carrier transport layer, and carrier blocking layer.

[0047] In this specification, a light-emitting device has an EL layer between a pair of electrodes. The EL layer has at least a light-emitting layer. Examples of layers (also called functional layers) that the EL layer has include a light-emitting layer, a carrier injection layer (hole injection layer and electron injection layer), a carrier transport layer (hole transport layer and electron transport layer), and a carrier blocking layer (hole blocking layer and electron blocking layer). In this specification, a light-receiving device (also called a photodetector) has at least an active layer that functions as a photoelectric conversion layer between a pair of electrodes. In this specification, one of the pair of electrodes may be referred to as a pixel electrode and the other as a common electrode.

[0048] In this specification, "island-like" refers to a state in which two or more layers made of the same material and formed in the same process are physically separated. For example, an island-like light-emitting layer refers to a state in which the light-emitting layer and an adjacent light-emitting layer are physically separated.

[0049] In this specification, the mask layer is located at least above the light-emitting layer (more specifically, the layer that is processed into an island shape among the layers constituting the EL layer) and has the function of protecting the light-emitting layer during the manufacturing process.

[0050] In this specification, a shape memory alloy is an alloy that, when plastically deformed below its shape recovery temperature, recovers to its original shape when heated above that temperature. The shape recovery temperature refers to the minimum temperature required for a shape memory alloy to recover from a plastically deformed state to its original shape.

[0051] In this specification, a display panel, which is one form of a display device, has the function of displaying (outputting) images or the like on its display surface. Therefore, a display panel is one form of an output device.

[0052] Furthermore, in this specification, a display panel on which a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) is attached, or on which an IC (Integrated Circuit) is mounted on the circuit board using a COG (Chip On Glass) method, may be referred to as a display panel module, display module, or simply a display panel.

[0053] In this specification, a touch panel, which is one form of a display device, has the function of displaying images, etc., on its display surface, and the function of a touch sensor that detects when a detectable object such as a finger or stylus touches, presses, or approaches the display surface. Therefore, a touch panel is one form of an input / output device.

[0054] A touch panel can also be called, for example, a display panel (or display device) with a touch sensor, or a display panel (or display device) with touch sensor functionality. A touch panel can also have a configuration comprising a display panel and a touch sensor panel. Alternatively, the display panel may have a touch sensor function located inside or on its surface.

[0055] Furthermore, in this specification, a touch panel substrate that includes connectors such as FPCs and TCPs, and ICs mounted using the COG method may be referred to as a touch panel module, display module, or simply a touch panel.

[0056] In this specification, flexibility refers to the property of an object being flexible and able to bend. It is the property of an object being able to deform in response to an external force applied to it, regardless of whether it is elastic or able to return to its original shape.

[0057] For example, flexible electronic devices, flexible display devices, flexible batteries (also called flexible batteries, etc.), and flexible substrates (also called flexible substrates, etc.) can each be deformed in response to external forces. Flexible electronic devices, flexible display devices, flexible batteries, and flexible substrates can each be used fixed in a deformed state, repeatedly deformed and used, or used in an undeformed state. The phrase "deformed in response to external forces" above means that they can be deformed by an average adult's hand without requiring excessive force. Furthermore, flexibility can be quantified as the deformation of an object in response to an external force using testing machines capable of measuring stress-strain (tensile testing machines, compression testing machines, etc.).

[0058] In this specification, when an object is described as having flexibility, it means that at least a part of the object is flexible. In other words, a flexible object may also have parts that are not flexible (which can be called rigid parts).

[0059] In this specification, when two objects are deformed by the same external force, the object that deforms more is said to be the object with higher flexibility. Also, when a first part and a second part of an object are deformed by the same external force, the part that deforms more is said to be the part with higher flexibility.

[0060] (Embodiment 1) This embodiment describes a display device according to one aspect of the present invention.

[0061] One aspect of the present invention comprises a flexible display unit (also called a flexible display), a shape memory alloy, and a heating element. The flexible display unit has a planar region and a curved region when bent. The shape memory alloy and the heating element have a region that overlaps with the curved region. The heating element is located on the opposite side of the flexible display from the shape memory alloy.

[0062] A flexible display according to one aspect of the present invention is composed of a laminate consisting of multiple layers (e.g., an element substrate, a light-emitting device, a color filter, etc.). For example, by applying a flexible display to the display portion of a foldable device, it becomes possible to repeatedly bend it. The ease with which a flexible display can be bent is influenced by several factors. In order to bend a flexible display, it is preferable to use a soft material (e.g., a material with a low Young's modulus) and to make the thickness of the folding portion thinner than the planar region. Furthermore, it is preferable to increase the curvature to such an extent that no bend marks are left when it is bent.

[0063] However, flexible displays made of soft materials have the problem of being easily deformed by external forces. Therefore, it is preferable to provide a support structure in addition to the flexible display. Shape memory alloys can be suitably used as a support structure for flexible displays. Compared to organic materials such as polyimide used as substrates for flexible displays, shape memory alloys have high mechanical strength and are less prone to deformation by external forces, such as when touching a touch panel. Therefore, it is preferable to use a shape memory alloy as a support structure to avoid the support structure being too soft against external forces, which can cause display malfunctions.

[0064] Furthermore, in one aspect of the present invention, when the flexible display is bent, the shape memory alloy supporting the flexible display and the flexible display itself may bend together as a single unit. To integrate the flexible display and the support, an adhesive layer can be provided between the flexible display and the support. This adhesive layer can be provided over part or all of the area where the flexible display and the support overlap.

[0065] In such a configuration, repeated bending may cause plastic deformation of the folding portion of the support, making it impossible to maintain its shape. However, if the support is made of a shape memory alloy, heating it above the shape recovery temperature when unfolding it will allow the support to recover its original shape. This mechanism allows the shape of the folding portion of the support to recover even after repeated bending and unfolding, thereby improving the durability of the folding portion of the support.

[0066] Shape memory alloys possessing such properties include Ni-Ti, Cu-Al-Ti, and Cu-Zn alloys. These alloys can maintain the shape of the folded portion by controlling the shape recovery temperature.

[0067] The heating element can be placed on top of the folding portion of the flexible display and support. This arrangement allows the heating element to heat the support of the folding portion. In particular, in the case of a support using a shape memory alloy, the shape of the shape memory alloy in the folding portion can be maintained by controlling the heating element to reach the shape recovery temperature.

[0068] Furthermore, it is preferable to provide a film-like heater in the heating element. In particular, a heater made of a flexible material is preferred. Because the heater is thin and flexible, it has almost no effect on the bending rigidity of the flexible display and the shape memory alloy. In this way, the folding section with the heater can be repeatedly bent and unfolded.

[0069] Preferably, the maximum temperature of the heat-generating part is above the shape recovery temperature of the shape memory alloy and below the heat resistance limit temperature of the flexible display. For example, when using an organic light-emitting diode (OLED) in a flexible display, the glass transition temperature (Tg) of the organic light-emitting diode can be used as an indicator of its heat resistance. By controlling the temperature of the heat-generating part to be above the shape recovery temperature and below the glass transition temperature of the organic compound contained in the light-emitting device, degradation of the flexible display (e.g., decrease in luminous efficiency, change in display color, etc.) can be suppressed, and the shape memory alloy can be restored to its original shape. This improves the reliability of the display device.

[0070] As an example of the operation method of a display device according to one aspect of the present invention, the shape memory alloy of the folding part can be restored to its original shape by simultaneously unfolding the flexible display and heating the shape memory alloy of the folding part to a temperature above the shape recovery temperature. In this way, the support deforms as the display surface repeatedly bends and unfolds, and the strain associated with the deformation of the support can be absorbed. This operation method makes it possible to realize a support in the folding part that possesses both mechanical strength and flexibility, thus enabling the bending and unfolding operation of a foldable display device with high display quality and high durability.

[0071] Below, we will explain more specific examples with reference to the diagrams.

[0072] [Configuration Example 1] Figure 1A shows a schematic cross-sectional view of a display device 20 according to one embodiment of the present invention. The display device 20 includes a display unit 30, a support 13, and a heating unit 17.

[0073] In this specification, the display unit 30, the support 13, and the heating unit 17 may be collectively referred to as the display device 20.

[0074] In the configuration shown in Figure 1A, the heating element 17 is located on the opposite side of the support 13 from the display unit 30. Also, in Figure 1B, the display device 20 mounted on the housing (specifically, housings 31, 32, and 35 shown in Figure 9B) that constitute the foldable device 40 described later is bent inward around the bending axis 51. Here, the bending axis refers to the center line of the part that is bent. Specifically, it is the axis that becomes the center of rotation when the display device 20 is bent. Note that in this specification, etc., the state in which the display unit 30 is bent so that it faces the bending axis 51 may be expressed as "bent inward".

[0075] [Display device 20] The display device 20 is configured to bend around the bending axis 51 and can bend and unfold in the direction of the vector 52 shown in Figure 1A. The display unit 30 can use a flexible display that can bend and unfold. The display device 20 has regions 14A, 14B, and 14C. In regions 14A and 14B, when the display device 20 is unfolded, the display unit 30 is supported by the support 13 to maintain a planar shape. In region 14C, the display device 20 bends so as to curve around the bending axis 51.

[0076] As shown in Figure 1B, by curving the display unit 30 around the bending axis 51, the regions 14A and 14B of the display unit 30 are positioned opposite each other.

[0077] [Display Unit 30] The display unit 30 has one or more light-emitting devices that can be mounted on a flexible substrate. The display unit 30 also has transistors, wiring, and capacitive elements. A pixel circuit is also provided, and this pixel circuit has the function of controlling the driving of the light-emitting devices. The light-emitting elements are electrically connected to one or more of the transistors, capacitive elements, and wiring of the display unit 30.

[0078] In the display unit 30, it is preferable to place a color filter in a position that overlaps with the light-emitting area. By providing a color filter, excellent display quality can be achieved without using a circular polarizer, and thus the display unit 30 can be made thinner. Furthermore, it is preferable to provide a layer that absorbs visible light in the non-light-emitting areas between pixels. Specifically, by stacking multiple color filters (blue, green, and red, etc.) in the non-light-emitting areas between pixels, visible light contained in ambient light can be absorbed, and the reduction in contrast due to ambient light reflection can be suppressed.

[0079] An EL element can be used as the light-emitting device of the display unit 30. For example, it is preferable to use an organic EL element as the light-emitting device of the display unit 30. Examples of light-emitting materials for the light-emitting device include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and inorganic compounds (quantum dot materials, etc.). Furthermore, LEDs such as micro-LEDs (Light-Emitting Diodes) can also be used as the light-emitting device.

[0080] The light-emitting color of the light-emitting device can be infrared, red, green, blue, cyan, magenta, yellow, or white. The display unit 30 may have light-emitting devices with different light-emitting colors. Furthermore, the color purity can be improved by adding a microcavity structure to the light-emitting device.

[0081] [Support 13] The support 13 is used to support the display unit 30. It is preferable to use a material with higher mechanical strength than the display unit 30. Figure 2A shows a schematic cross-sectional view of the support 13 when it is bent around the bending axis 51. The support 13 is composed of support 13A, support 13B, and support 13C. Supports 13A, 13B, and 13C are continuous and may each be a part of the area of ​​the support 13. Alternatively, these parts may be manufactured individually and joined later. Support 13C is located between support 13A and support 13B and is joined to them.

[0082] Support 13A is provided in a position overlapping with region 14A, and support 13B is provided in a position overlapping with region 14B. Support 13C is provided in a position overlapping with region 14C. Supports 13A and 13B allow the display unit 30 to maintain a planar shape. Support 13C can also be curved and unfolded together with the display unit 30.

[0083] To support the display unit 30 in a planar shape, it is preferable that the support members 13A and 13B have high rigidity. On the other hand, it is preferable that the support member 13C is more flexible than the support members 13A and 13B so that it can be bent, and also has higher rigidity than the display unit 30 so that when the display unit 30 is unfolded, it can support the folding portion of the display unit 30 in a planar shape.

[0084] It is preferable that the strain when the support 13C is bent is small. The smaller the strain, the lower the risk of breakage when the support 13C is bent. As shown in Figure 2B, the strain that occurs when the support 13C is bent at a curvature diameter R13 can be calculated using stress, Young's modulus, etc. In this specification, the strain is calculated by dividing the difference between the length of the outer surface 1311 (outer circumference) and the length of the inner surface 1321 (inner circumference) in the folding portion by the length of the inner circumference.

[0085] Referring to Figure 2B, the strain of the support 13C can be expressed as (length O13 - length I13) / (2 × length I13) × 100 (%). Here, length O13 is the length (outer circumference) of the outer surface 1311 of the support 13C that has curvature when viewed from the side. Length I13 is the length (inner circumference) of the inner surface 1321 of the support 13C that has curvature when viewed from the side. Alternatively, the strain can be expressed as strain = thickness T13 / curvature diameter R13, based on the relationship between the curvature diameter R13 and the thickness T13 of the folding portion when the support 13C is bent.

[0086] Furthermore, openings can be provided in the support 13C. For example, multiple openings can be provided. The openings can be of various sizes and shapes (e.g., grid-like), and these can be combined. In this configuration, the structure of the support 13C is made easily bendable, thereby reducing the risk of failure of the support 13C due to repeated bending and unfolding.

[0087] However, foldable devices are preferably made with a thin casing for portability, making it difficult to increase the curvature of the folding section. Also, in order to support the display unit 30, the support 13C is preferably thick enough to ensure a certain degree of mechanical strength. By using an appropriate material for the support 13C, plastic deformation of the display unit 30 and the support 13 can be suppressed.

[0088] As described above, it is preferable to use a shape memory alloy for the folding portion of the support 13 (specifically, the support 13C) where conflicting properties are required. Below, we will describe shape memory alloys that can be used for the support 13C.

[0089] [Shape Memory Alloy] As described above, a shape memory alloy is suitable for the folding portion of the support 13 (specifically, the support 13C) where conflicting properties are required. As the material, it is preferable to use an alloy composed of one or more metals selected from Au, Ag, Ni, Cu, Ni-Ti, In, Fe, etc. Such alloys are suitable as the support 13 because they have a shape memory effect. For example, Ni-Ti alloys and Ni-Ti-Cu alloys are preferred. The shape memory effect refers to the property of returning to its original shape after plastic deformation at a temperature below a certain temperature by heating.

[0090] The elastic deformation strain of shape memory alloys is greater than that of general metals. For example, with metals such as aluminum and stainless steel (SUS), the strain that allows for shape recovery is less than 1%. On the other hand, with shape memory alloys, strains up to about 8% can be kept within the range of elastic deformation, and deformations within this range can be restored to their original shape without heating. By configuring the support 13C so that the strain calculated from its thickness T13 and curvature diameter R13 is 8% or less, preferably 6% or less, the support 13C can be automatically returned to its original shape even after being bent.

[0091] Shape memory alloys have an elastic range, so in the case of elastic deformation, they can return to their original shape without plastic deformation. However, if the deformation exceeds the elastic range, the shape can be restored by heating above the shape recovery temperature. Here, the shape recovery temperature of a shape memory alloy can be adjusted by the alloy composition, heat treatment conditions, etc.

[0092] Furthermore, the shape recovery temperature can be changed by adjusting the mixing ratio of Ni and Ti in the Ni-Ti alloy. Here, the mixing ratio refers to the proportion of the elements constituting the alloy, such as the mass ratio, molar ratio, or atomic ratio. Specifically, by changing the mixing ratio of Ni and Ti by a few wt% in the vicinity of Ni:Ti = 50:50, the shape recovery temperature for restoring the shape can be adjusted within the range of 0°C to 100°C. Here, the vicinity of Ni:Ti = 50:50 means that the mass fraction of Ni is in the range of 53.5 to 57.5, and the mass fraction of Ti accounts for the remaining proportion.

[0093] Furthermore, the chemical composition of Ni-Ti alloys exhibiting shape memory effects can be determined based on or in reference to standards such as JIS H 7107.

[0094] Furthermore, the shape recovery temperature can vary depending not only on the Ni-Ti alloy composition ratio, but also on the processing conditions and heat treatment conditions.

[0095] Furthermore, in order to add characteristics that meet the required properties such as durability and strain recovery, elements such as Cu, Co, Cr, and Fe can be added to the Ni-Ti alloy as additive elements.

[0096] Figure 2C shows a schematic cross-sectional view of the process of restoring the shape of the support 13C made of shape memory alloy. The deformed body 13_1 is an example in which the width of the folding portion of the support 13C has been stretched from length D2 to length D1 due to strain, and a convex bending mark remains on the lower side of the support 13C. Even a deformed body 13_1 that has undergone plastic deformation in this way can be restored to its original shape, the recovered body 13_2, by heating it above the shape recovery temperature.

[0097] Figures 3A and 3B are schematic stress (Pa)-strain (%) curves illustrating the differences in the behavior of plastically deformed materials.

[0098] Figure 3A schematically illustrates the behavior of a material that undergoes plastic deformation when stress is applied, and then retains its original strain even after the stress is removed. The specific behavior will be explained below.

[0099] At point M1, the material is unloaded. Between point M1 and point M2, the material is loaded and deformed. At this stage, the material deforms within the elastic region, and returns to its original shape when the load is removed. In other words, the material returns to the state at point M1. If further load is applied from point M2 onwards, the material enters the plastic deformation region, and permanent strain occurs. Here, the crystal structure of the material changes, and it can no longer return to its original shape. When the load on the material is released (point M3), even after unloading, the material maintains its plastically deformed state (point M4), and permanent strain remains.

[0100] On the other hand, Figure 3B shows a schematic diagram of a case where a shape memory alloy undergoes plastic deformation due to strain, and the strain is removed by heating the plastically deformed shape memory alloy. The specific behavior will be explained below.

[0101] The behavior at points SM1, SM2, and SM3 exhibits the same stress-strain relationships as at points M1, M2, and M3. At point SM3, the material undergoes plastic deformation, and its crystal structure changes. Point SM4 represents the state of the material before heating, and the material retains some strain. By heating this material, it recovers to its original shape. This process is called shape recovery. In this way, the permanent strain is removed, and the material with the shape memory effect can recover its original shape.

[0102] [Heat-generating section 17] As shown in Figures 1A and 1B, the heat-generating section 17 is located on the opposite side of the support 13C from the display section 30. The heat-generating section 17 is located in the folding section of the display device 20 and is provided in an area that overlaps with the support 13C.

[0103] It is preferable that the heat-generating section 17 is located on the opposite side of the support 13C from the display section 30. Heat from the heat-generating section 17 can be transferred to the display section 30, potentially causing thermal stress on the display section 30. For example, if the display section 30 is a laminate having multiple adhesive layers, thermal stress may reduce the adhesive strength of these adhesive layers. Therefore, a configuration that efficiently transfers heat from the heat-generating section 17 to the support 13C while minimizing heat transfer to the display section 30 is preferable. By positioning the heat-generating section 17 on the opposite side of the support 13C from the display section 30 in order to ensure a sufficient distance between the heat-generating section 17 and the display section 30, deterioration of the display section 30 can be suppressed, resulting in a highly reliable display device.

[0104] Furthermore, in addition to the configuration in which the heating element 17 is located on the opposite side of the support 13C from the display unit 30, a configuration in which a material with high heat insulation properties is interposed between the support 13C and the display unit 30 can suppress the transfer of heat generated by the heating element 17 to the display unit 30.

[0105] The heating element 17 may be provided in direct contact with the support 13C, or an adhesive layer may be provided between the heating element 17 and the support 13C. By increasing the adhesion between the heating element 17 and the support 13C with the adhesive layer, heat can be efficiently conducted from the heating element 17 to the support 13C. In this way, a configuration can be achieved in which the heating element 17 generates heat to heat the support 13C.

[0106] The heating element 17 can be heated by means of, for example, resistance heating, electromagnetic induction heating, or laser heating. In particular, if the heating element 17 is a conductor, it can be heated by resistance heating by passing an electric current through it.

[0107] Furthermore, it is preferable to provide a film-like heater in the heating element 17. In particular, it is preferable to provide a heater made of a flexible material. For example, carbon nanotubes, graphene, and other materials can be used as flexible materials. Alternatively, a nichrome wire heater using a thin wire made of a nickel-chromium alloy (nichrome) can be used. Because the heater is thin and flexible, it has almost no effect on the bending rigidity of the flexible display and the shape memory alloy.

[0108] In one embodiment of the present invention, it is preferable to use a shape memory alloy as the support 13C. The heat generated by the heating element 17 can heat the shape memory alloy. The shape memory alloy has the function of restoring the shape of the support 13C to its shape before plastic deformation when heated above its shape recovery temperature.

[0109] Alternatively, the support 13C can be configured to generate heat. In this case, the support 13C can also function as the heat-generating part 17. Specifically, the support 13C has a first terminal on the side connected to the support 13A and a second terminal on the side connected to the support 13B. By passing current between these two terminals, the support 13C containing the shape memory alloy can be heated by resistance heating. In this configuration, since the support 13C itself generates heat, it is not necessary to provide a separate heat-generating part from the support 13C. As a result, weight reduction and thinning can be achieved without increasing the thickness of the folding part of the display device 20. In addition, since no additional configuration is required, manufacturing costs can be reduced.

[0110] The temperature at which the heating element 17 is driven is preferably below the heat resistance limit of the display unit 30 and above the shape recovery temperature of the shape memory alloy. The shape recovery temperature of the Ni-Ti alloy under certain manufacturing conditions is approximately 40°C to 60°C. On the other hand, when an organic EL element is used as the light-emitting device of the display unit 30, it is preferable to control the heating element 17 at a temperature below the glass transition temperature (Tg) of the organic compound contained in the light-emitting device. For example, less than 100°C is preferable. By controlling the temperature of the heating element 17 in the range of 40°C to less than 100°C, the deterioration of the display device 20 can be suppressed. Furthermore, since the shape memory alloy can recover its shape within this temperature range, reliability can be improved.

[0111] Figure 4 shows an example of a block diagram illustrating the schematic of a system for controlling the operation of the heating element 17. In a foldable display device 20, a shape recovery system 70 can be installed as a system associated with the unfolding operation. The shape recovery system 70 is a system that uses a shape memory alloy and a heating element 17 for heating the shape memory alloy in the folding part of the support 13, and has the function of returning the shape memory alloy to its original shape when the display device 20 is unfolded.

[0112] As shown in Figure 4, the display device 20 has a display unit 30, a support 13, and a heating unit 17, and the shape recovery system 70 has a heating unit 17, a heating control unit 71, a rotation angle sensor 81, a temperature sensor 82, a timer 83, and a temperature adjustment device 84.

[0113] The electronic equipment control unit 60 can control the heat generation control unit 71 and the display unit 30 of the display device 20. The electronic equipment control unit 60 has a logic circuit that has the function of controlling the overall operation of each device mounted on the electronic equipment.

[0114] The heat generation control unit 71 has the function of exchanging signals with each sensor and controlling the operation of the heat generation unit 17. Specifically, the heat generation control unit 71 acquires information from the rotation angle sensor 81 and the temperature sensor 82, and operates the heat generation unit 17 according to the flowchart (see Embodiment 2) based on this information. In addition, the heat generation control unit 71 controls the temperature of the heat generation unit 17 based on the temperature measured by the temperature sensor 82, and also controls the time using the timer 83. Based on these controls, it can send signals to the heat generation unit 17.

[0115] The temperature control device 84 has a function to forcibly stop the signal from the heat generation control unit 71 to the heat generation unit 17. It is preferable that the temperature control device 84 be configured to include a thermostat. In a temperature control device 84 equipped with a thermostat, the signal from the heat generation control unit 71 can be automatically cut off based on the detection of abnormal overheating by the temperature sensor 82. In this way, the safety of the heat generation unit 17 is ensured and damage due to abnormal overheating can be prevented.

[0116] Although the electronic equipment control unit 60 and the heat generation control unit 71 are shown as separate components, the electronic equipment control unit 60 and the heat generation control unit 71 may be treated as the same control unit.

[0117] A flowchart of the operation of the heating element 17 will be explained in Embodiment 2.

[0118] Figures 5A and 5B show specific configuration examples of the display unit 30, the support unit 13, and the heating unit 17. Figure 5A is a perspective view of the display device 20. Figure 5B is a cross-sectional view of Figure 5A taken from the X direction. An adhesive layer 19 and a filler 131U are provided between the display unit 30 and the support unit 13. In addition, an adhesive layer 131B is provided between the folding portion of the support unit 13C, that is, between the support unit 13C and the heating unit 17.

[0119] As shown in Figure 5B, the display device 20 has an adhesive layer 131B in contact with the heating element 17, a support 13C in contact with the adhesive layer 131B, an adhesive layer 19 on the support 13A and support 13B, a filler 131U on the support 13C, and a display unit 30 in contact with the adhesive layer 19 and filler 131U.

[0120] The heating element 17 is joined to the support 13C via the adhesive layer 131B. Alternatively, the heating element 17 may be joined to both the support 13A and the support 13B via the adhesive layer 131B. By having the end of the heating element 17 protrude outward beyond the end of the support 13C, the support 13C can be heated uniformly.

[0121] The adhesive layer 19 is located between the support 13 and the display unit 30 and has the function of bonding the support 13A and support 13C to the display unit 30. By bonding the mechanically strong support 13A and support 13B to the display unit 30, the regions 14A and 14B of the display unit 30 can be supported in a planar shape.

[0122] Various types of curing adhesives can be used as the adhesive layer, including UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used. In addition to the adhesive, thermally conductive materials such as graphene and graphite can be applied together with the adhesive sheet.

[0123] The filler 131U on the support 13C is provided to fill the gap between the display unit 30 and the support 13C. Preferably, the thickness of the filler 131U is the same as the thickness of the adhesive layer 19 in order to fill the gap created by providing the adhesive layer 19 in regions 14A and 14B. By providing the filler 131U, it is possible to suppress deformation that occurs when an external force is applied to the display unit 30 in the -Z direction.

[0124] The filler 131U can be made of a material that does not hinder the bending and unfolding states. In particular, a material that is flexible along the curvature direction of the display device 20 is preferred. Specifically, it is preferable to use silicone, polyimide film, etc. This reduces the resistance generated by the filler 131U when it is bent. It is also preferable to use a material that has better heat insulation properties than the adhesive layer 19. When the heating element 17 heats the support 13C, the diffusion of heat from the support 13C to the display unit 30 can be suppressed, thereby suppressing thermal deterioration of the display unit 30.

[0125] When an external force is applied to the display device 20 that causes it to bend, the fact that the display unit 30 and the support 13C are not bonded together allows for the reduction of stress on their folding parts. When multiple members are bonded together and laminated, the laminate becomes more difficult to bend than when only the individual members are bendable. To avoid this problem, the display device 20 has a configuration in which the display unit 30 and the support 13C can bend independently. This reduces the force required to bend the display device 20. Furthermore, the folding part of the display unit 30 is not affected by the plastic deformation of the support 13C. Therefore, when the display device 20 is unfolded, the display unit 30 can maintain its planar shape. In this way, a display device with high display quality can be achieved.

[0126] An adhesive layer 131B is provided to bond the heat-generating part 17 to the support 13C. Here, since the heat-generating part 17 is provided to heat the support 13, it is preferable to use a material with high thermal conductivity or thermal diffusivity for the adhesive layer 131B. If the adhesive layer 131B has low thermal conductivity, the heat transfer efficiency from the heat-generating part 17 to the support 13C may decrease. Furthermore, in order to improve heat conduction, it is preferable that the adhesive layer 131B that bonds the heat-generating part 17 to the support 13C is thinner than the heat-generating part 17. A thin adhesive layer 131B can improve the transfer of heat from the heat-generating part 17 to the support 13C.

[0127] In the example configuration in which the support 13C also functions as the heat-generating part 17, the heat-generating part 17 and the adhesive layer 131B become unnecessary.

[0128] In the configuration example shown in Figures 6A to 6C, the support 13 is composed of a support 13A overlapping with the region 14A of the display device 20, a support 13B overlapping with the region 14B of the display device 20, and a support 13C overlapping with the region 14C of the display device 20. In this configuration, terminals for conducting current are added to allow the support 13C to self-heat through resistive heating or the like. Here, self-heating refers to generating heat due to the properties of the material itself, without relying on an external heat source, for example, when the support 13C generates heat through resistive heating. Figure 6A is a perspective view of the display device 20 when the support 13C also serves as the heating element 17. Figures 6B and 6C are cross-sectional views taken from the X direction of Figure 6A. In Figure 6A, the display unit 30 of the display device 20 is omitted. In the configuration shown in Figure 5B, it is also possible to provide an adhesive layer 19 and a filler 131U between the display unit 30 and the support 13.

[0129] Figures 6B and 6C illustrate a case using a support 13C, which is considered a resistor, a power supply 16, and a switch SW13. In Figure 6B, SW13 is in the off state, and in Figure 6C, SW13 is in the on state. The support 13C is made of a shape memory alloy and can recover its shape by heating.

[0130] As shown in Figures 6B and 6C, one terminal can be connected to the support 13C on the side that connects to support 13A, and the other terminal can be connected to the support 13C on the side that connects to support 13B. The switch SW 13 is connected in series between the support 13C and the power supply 16. Specifically, one terminal of the support 13C is connected to one side of the power supply 16, the other terminal of the support 13C is connected to one terminal of the switch SW 13, and the other terminal of the switch SW 13 is connected to the other side of the power supply 16. Region 13TH is the part of the support 13C that generates heat through resistive heating.

[0131] Figure 6B is a conceptual diagram showing the state after the support 13C has been curved and plastically deformed, and then unfolded. On the other hand, Figure 6C shows the state after the support 13C has recovered to its original shape by resistance heating. These conceptual diagrams show that when the support 13C is curved, it stretches in the Y direction (the width of the support 13C in the Y direction in the figure is width D1), and when heated, it contracts in the Y direction (the width of the support 13C in the Y direction in the figure is width D2). Note that the operation of the support 13C due to plastic deformation is just one example, and different plastic deformations may occur, for example, as shown in Figure 2C.

[0132] [Application Example] A display device according to one aspect of the present invention can be applied to the display section of a foldable device. When the foldable device is unfolded and used, the display surface can be used in a flat state. On the other hand, when the foldable device is folded, the display surface of the display device has a planar area and a curved area. This configuration is realized by partially joining the display device to the housing of the foldable device.

[0133] Figure 7A shows a cross-sectional view of the folding portion and surrounding area of ​​the display device 20 when the foldable device 40 is folded. Figure 7B shows two different configurations of the display device 20 as embodiments of the present invention. Specifically, one configuration has adhesive layers 47 and 48 provided at the ends of the folding portion, and the other configuration does not fix the ends of the folding portion.

[0134] Housings 31 and 32 are components that make up the foldable device 40. Although not shown in Figures 7A and 7B, housings 31 and 32 are joined to the display device 20 via an adhesive layer. Specifically, housings 31 and 32 are joined to the display device 20 in the portions that overlap with the planar regions of the display device 20 (for example, regions 14A and 14B in Figure 5A).

[0135] Furthermore, as shown in Figure 7A, an adhesive layer 131B is provided to join the heating element 17 to the support 13A, support 13B, and support 13C. The display unit 30 is also joined to the support 13A and support 13B by an adhesive layer 19. A filler 131U is provided between the support 13C and the display unit 30.

[0136] The housing 31 is joined to the heating element 17 via an adhesive layer 47. Similarly, the housing 32 is joined to the heating element 17 via an adhesive layer 48. Here, adhesive layers 47 and 48 are provided at the ends of the folding portion of the display device 20. This fixes the ends of the folding portion of the display device 20, preventing unintended changes in its curvature.

[0137] Figure 7B shows two examples of display devices. One is a display device 20 in which the end of the folding portion is fixed with an adhesive layer (see dashed line), and the other is a display device 20X in which the end of the folding portion is not fixed (see solid line).

[0138] If the ends of the folding portion of the display device 20X are not fixed, stress-induced strain cannot escape perpendicular to the surfaces of the housings 31 and 32, potentially causing deformation into an unintended shape. The display device 20 can bend with a radius of curvature R around the bending axis 51. However, horizontal strain relative to the surfaces of the housings 31 and 32 may change the radius of curvature R of the bending axis. Specifically, as the bending axis 51 moves to the bending axis 51X, the radius of curvature R may become smaller, like the radius of curvature RX. As a result, if the ends of the folding portion are not fixed, it becomes difficult to maximize the radius of curvature, and the display device 20 may bend into an unintended shape.

[0139] In the display device 20, by fixing the ends of the folding portion with adhesive layers 47 and 48, a portion of the stress on the display device 20 can be directed perpendicular to the housings 31 and 32. By fixing the display device 20 with adhesive layers 47 and 48, the curvature of its folding portion can be maximized. In this way, by joining the housing and the display device via adhesive layers, it is possible to prevent the display device 20 from bending into an unintended shape.

[0140] Figure 8 shows an example of the configuration of the foldable device 40 in a folded state. It also shows a magnified view of the area near the curved portion (indicated by the dashed line) of the display device 20 provided on the foldable device 40.

[0141] The foldable device 40 includes a housing 31, a housing 32, a housing 35, a protective layer 311A, a protective layer 321A, a display device 20, a hinge 45, a hinge 46, a spacer 33, a spacer 34, a rotating plate 41, and a rotating plate 42. The hinge 45 has a rotating plate 41 and a rotational axis 43, and the housing 31 is joined to the housing 35 via the hinge 45. The hinge 46 has a rotating plate 42 and a rotational axis 44, and the housing 32 is joined to the housing 35 via the hinge 46. The spacer 33 supports area 14A of the display device 20, and the spacer 34 supports area 14B of the display device 20. The rotating plate 41 and adhesive layer 47 support a portion of area 14C of the display device 20. The rotating plate 42 and adhesive layer 48 support a portion of area 14C of the display device 20. Furthermore, protective layer 311A ​​is provided on housing 31, and protective layer 321A is provided on housing 32. Also, protective layers 311A ​​and 321A are arranged on the outer periphery of housings 31 and 32 so as to surround the display device 20. When the foldable device 40 is folded, protective layers 311A ​​and 321A may come into contact with each other. When the foldable device 40 is folded, housings 31 and 32 have a curved shape so as not to interfere with housing 35.

[0142] Referring to the enlarged view of Figure 8, the spacer 33 is provided on the housing 31 via an adhesive layer 33B. The spacer 33 is a support for the display device 20 and is joined to the display device 20 via an adhesive layer 33U. Furthermore, the thickness of the display device 20 on the spacer 33 is thinner than the thickness of the folding portion.

[0143] Similarly, referring to the enlarged view of Figure 8, the spacer 34 is provided on the housing 32 via an adhesive layer 34B. The spacer 34 is a support for the display device 20 and is joined to the display device 20 via an adhesive layer 34U. In the configuration in which the heating element 17 is provided in the folding section, the thickness of the display device 20 on the spacer 34 is thinner than the thickness of the components constituting the display device 20 in the folding section.

[0144] Spacers 33 and 34 are preferably made of lightweight and mechanically strong materials, and even more preferably of materials with high heat conductivity. For example, graphite and carbon nanotubes are lightweight and mechanically strong materials. Aluminum, titanium, and metal alloys also have high heat conductivity. By selecting such materials, for example, after the shape memory alloy recovers its shape due to heating, the high-temperature region can be quickly dissipated.

[0145] The protective layer 311A ​​and protective layer 321A are provided in contact with the housing 31 and housing 32, respectively. The protective layer 311A ​​and protective layer 321A function as stoppers when the foldable device 40 is bent. As materials for these layers, plastic, rubber such as silicone, metal, metal alloy, and ceramics can be used. It is preferable that these protective layers be thicker than the display device 20. In this way, the display unit 30 of the display device 20 can be positioned so that it does not come into contact with the foldable device 40 even when it is bent.

[0146] The protective layers 311A ​​and 321A may be positioned so as to partially overlap the display unit 30. In particular, the area around the display unit 30 may be designated as a non-display area where the pixel driving circuit is provided. In such cases, by positioning the protective layers 311A ​​and 321A around the display unit 30, the area around the display unit 30 can be protected even when external force is applied. In this way, direct contact between the display units 30 can be prevented, and the reliability of the display device can be improved. The protective layers 311A ​​and 321A will be explained later with reference to separate figures (Figures 10 and 11).

[0147] The display device 20 is positioned inside the space formed by the housings 31, 32, and 35 when the foldable device 40 is folded.

[0148] Housings 31 and 32 are connected to housing 35 via hinges, thereby allowing them to function as a mechanism. Rotating plates 41 and 42 are rotatably attached to housings 31 and 32, respectively, on housing 35. Specifically, housing 31 can rotate via rotating plate 41, and housing 32 can rotate via rotating plate 42.

[0149] When the housing 31 connected to housing 35 is unfolded, a virtual rotational axis 43 exists. Similarly, when the housing 32 connected to housing 35 is unfolded, a virtual rotational axis 44 exists. Here, the rotational axes 43 and 44 may be actual physical axes, or they may be axes virtually defined by the operation of the mechanism. In reality, such virtual axes can be set even if no physical axes exist.

[0150] The foldable device 40 may have a mechanism that causes the housings 31 and 32 to rotate synchronously when the hinges 45 and 46 are folded, by linking their rotations. Specifically, a first gear that rotates hinge 45 and a second gear that rotates hinge 46 can be combined to link these gears. Alternatively, another gear can be provided to further link the first gear and the second gear. It is preferable to synchronize the rotations of hinges 45 and 46 using such a gear mechanism.

[0151] In this specification, definitions of gear geometry may be based on or referenced from standards such as JIS B 0102-1.

[0152] When viewed from the X direction in Figure 8, when the foldable device 40 is unfolded, the first spur gear on the rotational axis 43 rotates counterclockwise (from the Y direction to the Z direction), and the second spur gear on the rotational axis 44 rotates clockwise (from the Z direction to the Y direction). To synchronize these rotations, a pair of spur gears can be combined. Here, a spur gear (also called a spur gear) refers to a cylindrical gear with straight teeth and a shape parallel to the axis. Furthermore, a third spur gear that rotates in the opposite direction to the first spur gear and a fourth spur gear that rotates in the opposite direction to the second spur gear can be combined. The first spur gear and the third spur gear can be combined, the third spur gear and the fourth spur gear can be combined, and the fourth spur gear and the second spur gear can be combined. In this way, the gear trains (combinations of gear pairs) of the first to fourth spur gears are linked, and the rotations of the hinges 45 and 46 can be synchronized. Furthermore, the center distance between the gear pairs of the second and fourth spur gears may be changed relative to the center distance between the gear pairs of the first and third spur gears (also called the center distance between parallel-axis gear pairs). This allows these gears to be housed inside the housing 35.

[0153] In the example above, a gear train consisting of four spur gears was shown, but by adding multiple additional gear pairs between the third and fourth spur gears, a mechanism can be provided to synchronize the rotational axis 43 and the rotational axis 44.

[0154] Alternatively, a helical gear may be used to connect the first spur gear and the second spur gear. A helical gear is a cylindrical gear with teeth arranged in a helical shape. One helical gear is placed between the first spur gear and the second spur gear, and these are combined to form a gear train. The rotation axis of the helical gear can rotate perpendicular to the rotation axes of the first spur gear and the second spur gear. This allows the first spur gear and the second spur gear to be connected and rotated by a single helical gear. Furthermore, by using such a helical gear, the number of parts can be reduced compared to the case where other spur gears are combined between the first and second spur gears to form a gear train. In this way, the space required for the mechanism in which the rotational axis 43 and the rotational axis 44 are synchronized can be reduced.

[0155] As shown in Figures 9A to 9C, the foldable device 40 is shown being folded and unfolded. Figure 9A shows the foldable device 40 in a folded state. Figure 9B shows an example of the transition process from the folded state to the unfolded state of the foldable device 40. Figure 9C shows the foldable device 40 in an unfolded state. When the foldable device 40 is folded, the display device 20 has both planar and curved regions. When the foldable device 40 is unfolded, the display device 20 becomes substantially planar.

[0156] When the foldable device 40 is folded (Figure 9A), the initial rotation angles of the rotation axis 43 and the rotation axis 44 are set to 0 degrees. When the foldable device 40 is unfolded (Figure 9C), the rotation axis 43 rotates 90 degrees counterclockwise, and the rotation axis 44 rotates 90 degrees clockwise. At this time, when the rotation angles of the rotation axis 43 and the rotation axis 44 each reach 90 degrees, the display device 20 is unfolded into a planar shape.

[0157] Here, the rotational axis 43 rotates counterclockwise within a range of 0 to 90 degrees, and the rotational axis 44 rotates clockwise within a range of 0 to 90 degrees. Furthermore, the state in which the housings 31 and 32 are relatively open to 180 degrees refers to the state in which the rotational axis 43 rotates 90 degrees counterclockwise and the rotational axis 44 rotates 90 degrees clockwise.

[0158] Regardless of the state of the foldable device 40, it is preferable that the housings 31 and 32 and the housing 35 each have areas in contact with each other. In Figure 9A, area 49A is the area where housings 31 and 35 are in contact. Area 49B is the area where housings 32 and 35 are in contact. In Figure 9C, area 49C is the area where housings 31 and 32 are in contact. Area 49C is the area where housings 31 and 32 and housing 35 are in contact. As shown in Figure 9, each component is in contact with each other, which allows the foldable device to operate properly.

[0159] By shaping the housings appropriately so that no gaps form between them, regions 49A, 49B, and 49C can be provided. In this way, it is possible to prevent foreign matter from entering through gaps in the joints between the housings, thereby reducing the amount of foreign matter entering the interior.

[0160] It is preferable to provide a material with a low coefficient of friction in areas where the housings come into contact, such as areas 49A and 49B. This allows the foldable device 40 to operate smoothly.

[0161] It is preferable to use a self-lubricating material as a material with low frictional resistance. Self-lubricating means that the friction coefficient of the material itself is extremely low. Examples of plastics with high self-lubricating properties include polyacetal, nylon 6, nylon 66, polytetrafluoroethylene (PTFE), and ultra-high molecular weight polyethylene. Using such a self-lubricating material is preferable because it reduces the effect of frictional resistance associated with bending and opening / closing the housing, and suppresses wear on the contact parts.

[0162] A foldable device 40 according to one aspect of the present invention will be described using perspective views and plan views to explain its constituent components. Figure 10A is an example of a perspective view of the foldable device 40 shown in Figure 9C. Figure 10B is an example of a plan view of the foldable device 40 when the cross-sectional view of Figure 9C is viewed from above. Similarly, Figure 10C is a plan view of the foldable device 40 with the protective layer 311A, protective layer 321A, and display device 20 removed.

[0163] The foldable device 40 is composed of a housing 31, a housing 32, and a housing 35. Housings 31 and 35 are joined via a rotating plate 41, allowing for the rotational movement shown in Figures 9A to 9C. Similarly, housings 32 and 35 are joined via a rotating plate 42, allowing for the rotational movement shown in Figures 9A to 9C. Protective layers 311A ​​and 321A are provided on housings 31 and 32, respectively. It is preferable that protective layers 311A ​​and 321A are members for protecting the display device 20 and are not provided in contact with the display unit 30 of the display device 20.

[0164] Furthermore, in order to avoid interfering with the operation of the foldable device 40, it is preferable not to provide protective layers 311A ​​and 321A in a portion of the folding area 14C. If it is difficult to provide a material with high mechanical strength, such as protective layers 311A ​​and 321A, in the area 14C, an alternative material can be provided to protect the folding portion of the display unit 30. For example, it is preferable to provide a flexible material such as rubber or plastic.

[0165] Figure 11 is a perspective view showing a part of the configuration of the foldable device 40 shown in Figure 10A. Protective layers 311A ​​and 321A are provided on the housing 31 and housing 32, respectively, to protect the display surface of the display unit 30. The display unit 30 is provided on top of supports 13A, 13B and 13C. Support 13C is provided on the heating unit 17, support 13A is provided on the spacer 33, and support 13B is provided on the spacer 34. In this specification, the display unit 30, supports 13A, 13B, 13C and the heating unit 17 may be collectively referred to as the display device 20.

[0166] As shown in Figure 9A, the protective layer 311A ​​and protective layer 321A can be configured to be in contact with the housing 31 and housing 32, respectively, and not in contact with the display surface of the display unit 30. Alternatively, the protective layer 311A ​​and protective layer 321A may be positioned to overlap a portion of the display area of ​​the display unit 30. In particular, the protective layer 311A ​​and protective layer 321A are provided to surround the periphery of the display unit 30 in a frame-like manner, except for at least a portion of the folding portion. Furthermore, by positioning the protective layer 311A ​​and protective layer 321A to protrude by a specific height from the upper end of the display unit 30, a configuration can be made to prevent the display unit 30 from receiving direct force from external forces. In this way, by preventing force from being applied due to direct contact between the display units, damage to the display device can be prevented and the reliability of the display device can be improved.

[0167] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0168] (Embodiment 2) In this embodiment, an operating method of one aspect of the present invention will be described with reference to Figures 12 and 13.

[0169] Figures 12 and 13 are flowcharts illustrating the operation method of one embodiment of the present invention.

[0170] <Example of Operation Method 1> Below, a more specific example of an operation method is shown. Referring to the block diagram of a display device according to one embodiment of the present invention shown in Figure 4, an example of the operation of heating the heating element 17 for restoring the shape memory alloy will be explained based on a flowchart. Figures 12 and 13 are flowcharts of the operation method of the heating element 17 of the foldable device 40 described below. The flowchart comprises steps S1 to S9.

[0171] Step S1: First, in step S1, it is confirmed whether or not the operation flow for heating the heating element 17 is started. The start of the operation flow is confirmed by detecting a change in the rotation angle of the foldable device 40 when the housing of the foldable device 40 is folded, or at an intermediate angle between the folded and unfolded state (YES in step S1). On the other hand, if no change in the rotation angle of the housing is detected (NO in step S1), the operation flow for heating the shape memory alloy is terminated.

[0172] The unfolding operation of the foldable device 40 can be detected, for example, by the following method. When the foldable device 40 is unfolded, the relative positions of the housing 31 and housing 32 change, so a method for detecting the positional relationship between housing 31 and housing 32 will be described with reference to Figures 9A to 9C. The components directly involved in the unfolding of the foldable device 40 consist of housing 31, housing 32, housing 35, hinge 45, and hinge 46. Here, hinge 45 has a rotating plate 41 and a rotational axis 43, and housing 31 is joined to housing 35 via hinge 45. Similarly, hinge 46 has a rotating plate 42 and a rotational axis 44, and housing 32 is joined to housing 35 via hinge 46. In this configuration, the relative positional relationship between housing 31 and housing 32 (also called the folding angle of the housings) can be detected using a rotational angle sensor 81.

[0173] The rotation angle sensor 81 is connected, for example, to the rotational axis of the housings 31 and 32 (specifically, the rotational axis 43 and the rotational axis 44), and can detect the angle change that occurs when the housings 31 and 32 rotate. The rotation angle sensor 81 can detect the relative positional relationship of the housings 31 and 32 by using methods such as a method that uses the Hall effect or a method that uses optical changes. By analyzing the signal detected by the rotation angle sensor 81 in the electronic equipment control unit 60 or the heat generation control unit 71, the rotation angle can be calculated and rotational motion can be detected.

[0174] For example, a Hall effect position sensor can be used as the rotation angle sensor 81. A Hall effect position sensor is a type of sensor that detects changes in a magnetic field and outputs a voltage signal. The voltage signal output by the Hall effect position sensor changes according to the strength of the magnetic field. Specifically, the voltage signal increases when a magnet approaches and decreases when the magnet moves away. By utilizing this characteristic, the Hall effect position sensor can detect rotation angle, position, etc. For example, when the magnet provided on the hinge of the foldable device 40 rotates, the magnetic field changes, and the voltage signal output by the Hall effect position sensor also changes. By analyzing the change in the magnetic field in the electronic equipment control unit 60 or the heat generation control unit 71, the unfolding of the foldable device 40 can be detected.

[0175] Step S2 Next, in step S2, the rotation angle of the foldable device 40 is obtained. A rotation angle sensor 81 can be used to obtain the rotation angle.

[0176] Step S3 Next, in step S3, it is confirmed whether or not the foldable device 40 has been unfolded. Specifically, the state in which the relative angle between the housing 31 and the housing 32 is substantially 180 degrees is considered to be the unfolded state of the foldable device 40. If the foldable device 40 has not been unfolded into a substantially planar shape (NO in step S3), the process returns to the operation step for detecting the change in the rotation angle of the housing (step S1), and the operations from step S1 onwards are continued. On the other hand, if the foldable device 40 has been unfolded into a substantially planar shape (YES in step S3), the process proceeds to step S4.

[0177] Next, from step S4 to step S9, the heating control unit 71 controls the heating section 17 to heat the shape memory alloy constituting the support 13. Depending on the determination described below, the state from step S5 to step S7 may loop.

[0178] Step S4: In step S4, the heat generation control unit 71 starts controlling the heat generation unit 17 for heating the shape memory alloy that constitutes the support 13.

[0179] Step S5 Next, in step S5, it is checked whether the temperature TEM1 of the heating element 17 has reached the shape recovery temperature TEM2 of the shape memory alloy. If it is determined that the temperature TEM1 of the heating element 17 is less than the shape recovery temperature TEM2 (YES in step S5), the process proceeds to step S6.

[0180] Furthermore, if the temperature TEM1 of the heat-generating section 17 is determined to be equal to or greater than the shape recovery temperature TEM2 (NO in step S5), the process proceeds to step S8.

[0181] A film-like heater may be provided as the heating element 17. In particular, when the heating element 17 is provided in region 14C of the support 13C, a heater made of a flexible material is preferred. For example, carbon nanotubes, graphene, and other materials can be used as flexible materials. Alternatively, a nichrome wire heater using a thin wire made of a nickel-chromium alloy (nichrome) can be used. Because the heater is thin and flexible, it does not significantly affect the bending rigidity of the flexible display and the support 13, so the heating element 17 can maintain the degree of freedom of the curved and unfolded states of region 14C.

[0182] Heat transfer efficiency can be improved by bonding a film-shaped heater and a shape memory alloy with an adhesive layer. It is preferable to use a material for the adhesive layer that has a high heat transfer coefficient, high adhesive strength, excellent thermal stability at high temperatures, and flexibility. Specifically, it is preferable to use rubber-like materials or gel-like materials containing silicone, acrylic resin, or urethane resin. In particular, it is preferable to use silicone gel, silicone gel containing low molecular weight siloxane, acrylic gel, or urethane gel-like materials.

[0183] Step S6: Next, in step S6, the shape memory alloy is heated by generating heat through the heating element 17, such as by passing an electric current through it.

[0184] Step S7 Next, in step S7, it is checked whether the temperature TEM1 of the heating element 17 has reached the shape recovery temperature TEM2 of the shape memory alloy. If it is determined that the temperature TEM1 of the heating element 17 is equal to or greater than the shape recovery temperature TEM2 (YES in step S7), the process proceeds to step S8.

[0185] Furthermore, if in step S7 the temperature TEM1 of the heat-generating section 17 is determined to be less than the shape recovery temperature TEM2 (NO in step S7), the process proceeds to step S5.

[0186] Step S8 Next, in step S8, when it is confirmed that the temperature TEM1 of the heating element 17 has reached the shape recovery temperature TEM2 of the shape memory alloy, the heating control unit 71 stops the process of supplying current to the heating element 17.

[0187] Step S9 Next, in step S9, the process of generating heat in the heat-generating unit 17 is terminated by stopping the heat-generating control unit 71 with the electronic equipment control unit 60.

[0188] Furthermore, in order to prevent unintended high temperatures (also known as abnormal overheating), the flexible display may be equipped with a temperature control device (e.g., a thermostat) that detects abnormal overheating and adjusts the temperature. For example, if the thermostat detects abnormal overheating, it can be configured to automatically shut off the heater current. In this case, a control system independent of the control by the heat generation control unit 71 can be provided. In this way, even if a malfunction occurs in the heat generation control unit 71, abnormal overheating of the heat generation unit 17 can be prevented.

[0189] As a result, when the foldable device 40 according to one aspect of the present invention is unfolded, the support 13C to which the shape memory alloy is applied is heated to a temperature above the shape recovery temperature, causing the support 13C to recover its shape. In this way, the surface of the display unit 30 supported by the support 13C can be unfolded without warping. As a result, the display unit 30 on the support 13 is unfolded without warping of its surface, making it possible to provide a flexible display with high display quality.

[0190] <Example of operation method 2> Figure 13 shows an example in which a timer (step S10) is applied between step S7 and step S8 in the above-mentioned Example of operation method 1.

[0191] Step S10: In step S10, a timer is used to measure a certain amount of time after the temperature TEM1 of the heating element 17 reaches the shape memory alloy's shape recovery temperature TEM2. After that, the heating control unit 71 stops heating the heating element 17 (step S8). In this way, by heating within the timer setting time (for example, a few seconds to a few minutes), the shape memory alloy can be restored to its original shape.

[0192] Furthermore, the automatic shut-off function via a timer prevents overheating even in the event of a malfunction in the heat control unit. In addition, the inclusion of a thermostat improves safety when the heat-generating unit 17 overheats.

[0193] This embodiment can be combined with other embodiments as appropriate.

[0194] (Embodiment 3) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 14 to 19.

[0195] The display device of this embodiment can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television equipment, desktop or notebook computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal information terminals, and audio playback devices.

[0196] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used, for example, as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, as well as as a display unit for wearable devices that can be worn on the head, such as VR devices such as head-mounted displays (HMDs) and AR devices such as glasses.

[0197] A semiconductor device according to one aspect of the present invention can be used as a display device or a module having said display device. Examples of modules having said display devices include a module to which a connector such as a flexible printed circuit board (FPC) or TCP (Tape Carrier Package) is attached, and a module on which an integrated circuit (IC) is mounted using the COG (Chip On Glass) method or COF (Chip On Film) method.

[0198] The display device of this embodiment may also function as a touch panel. For example, the display device can be fitted with various detection elements (also called sensor elements) that can detect the proximity or contact of an object to be detected, such as a finger.

[0199] Examples of sensor types include capacitive, resistive, surface acoustic wave, infrared, optical, and pressure-sensitive sensors.

[0200] Examples of capacitance methods include surface capacitance and projected capacitance. Furthermore, projected capacitance methods include self-capacitance and mutual capacitance. Mutual capacitance is preferable because it enables simultaneous multi-point detection.

[0201] Examples of touch panels include out-cell, on-cell, and in-cell types. An in-cell touch panel refers to a configuration in which electrodes constituting the sensing element are provided on one or both of the substrate supporting the display element and the opposing substrate.

[0202] <Example of Display Device Configuration 1> Figure 14 shows a perspective view of the display device 500A.

[0203] The display device 500A has a configuration in which substrate 152 and substrate 151 are bonded together. In Figure 14, substrate 152 is shown with a dashed line.

[0204] The display device 500A includes a display unit 162, a connection unit 140, a circuit unit 164, a conductive layer 165, etc. Figure 14 shows an example in which IC 173 and FPC 172 are mounted on the display device 500A. Therefore, the configuration shown in Figure 14 can also be described as a display module having the display device 500A, an IC, and an FPC.

[0205] The connection portion 140 is provided on the outside of the display unit 162. The connection portion 140 can be provided along one or more sides of the display unit 162. There can be one or more connection portions 140. Figure 14 shows an example in which the connection portion 140 is provided so as to surround all four sides of the display unit 162. The common electrode of the display element and the conductive layer are connected at the connection portion 140, and a potential can be supplied to the common electrode.

[0206] The circuit section 164 includes, for example, a scan line drive circuit (also called a gate driver). Alternatively, the circuit section 164 can be configured to include both a scan line drive circuit and a signal line drive circuit (also called a source driver).

[0207] The circuit section 164 can utilize various circuits, including shift register circuits, level shifter circuits, inverter circuits, latch circuits, analog switch circuits, demultiplexer circuits, and logic circuits. The circuit section 164 can also utilize transistors and capacitive elements. The transistors in the circuit section 164 can be formed using the same process as the transistors in the pixel circuit.

[0208] The conductive layer 165 has the function of supplying signals and power to the display unit 162 and the circuit unit 164. These signals and power are input to the conductive layer 165 from the outside via the FPC 172, or from the IC 173.

[0209] Figure 14 shows an example in which IC 173 is mounted on the substrate 151 using the COG method. IC 173 can be an IC having, for example, one or both of a scan line drive circuit and a signal line drive circuit. Note that the display device 500A and the display module can also be configured without an IC. Furthermore, the IC can be mounted on the FPC using the COF method or the like.

[0210] A semiconductor device according to one aspect of the present invention can be applied, for example, to one or both of the display unit 162 and the circuit unit 164 of a display device 500A. Oxide semiconductors (OS) can preferably be used in the channel formation region of the transistors in the display device. By using OS transistors, a display device with low power consumption can be made. Furthermore, the semiconductor device according to one aspect of the present invention can be used in both the display unit 162 and the circuit unit 164, that is, all of the transistors in the display device can be OS transistors. By making all of the transistors in the display device OS transistors in this way, the manufacturing cost can be kept low.

[0211] For example, when a semiconductor device according to one aspect of the present invention is applied to the pixel circuit of a display device, the occupied area of ​​the pixel circuit can be reduced, resulting in a high-definition display device. Also, for example, when a semiconductor device according to one aspect of the present invention is applied to the drive circuit of a display device (for example, one or both of a gate line drive circuit and a source line drive circuit), the occupied area of ​​the drive circuit can be reduced, resulting in a narrow-bezel display device. Furthermore, because the semiconductor device according to one aspect of the present invention has good electrical characteristics, its use in a display device can improve the reliability of the display device.

[0212] The display unit 162 is the area in the display device 500A that displays images, and has a plurality of pixels 201 arranged periodically. Figure 14 shows a magnified view of one pixel 201.

[0213] There are no particular limitations on the pixel arrangement in the display device of this embodiment, and various methods can be applied. Examples of pixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements.

[0214] The pixel 201 shown in Figure 14 has a sub-pixel 11R that emits red light, a sub-pixel 11G that emits green light, and a sub-pixel 11B that emits blue light. The number of sub-pixels that a single pixel has is not particularly limited.

[0215] Each sub-pixel 11R, sub-pixel 11G, and sub-pixel 11B includes a display element and a circuit that controls the driving of the display element.

[0216] Various elements can be used as display elements, such as liquid crystal elements and light-emitting devices. In addition, display elements using shutter-type or optical interference-type MEMS (Micro Electro Mechanical Systems), microcapsule-type, electrophoretic-type, electrowetting-type, or electronic powder fluid (registered trademark)-type methods can also be used. Furthermore, QLEDs (Quantum-dot LEDs) using a light source and color conversion technology with quantum dot materials can be used.

[0217] Examples of quantum dot materials used in the color conversion layer include Group 14 elements, Group 15 elements, Group 16 elements, compounds consisting of multiple Group 14 elements, compounds of elements belonging to Groups 4 to 14 and Group 16 elements, compounds of Group 2 elements and Group 16 elements, compounds of Group 13 elements and Group 15 elements, compounds of Group 13 elements and Group 17 elements, compounds of Group 14 elements and Group 15 elements, compounds of Group 11 elements and Group 17 elements, iron oxides, titanium oxides, chalcogenide spinels, and various semiconductor clusters.

[0218] Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, indium arsenide, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, gallium nitride, indium antimonide, gallium antimonide, aluminum phosphide, aluminum arsenide, aluminum antimonide, lead selenide, lead telluride, lead sulfide, indium selenide, telluride Indium sulfide, indium sulfide, gallium selenide, arsenic sulfide, arsenic selenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide, aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride, calcium sulfide, gallium selenide Calcium, calcium telluride, beryllium sulfide, beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin selenide, tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molybdenum sulfide, vanadium oxide, tungsten oxide, tungsten oxide Examples include carbon dioxide, titanium dioxide, zirconium dioxide, silicon nitride, germanium nitride, aluminum oxide, barium titanate, compounds of selenium, zinc, and cadmium, compounds of indium, arsenic, and phosphorus, compounds of cadmium, selenium, and sulfur, compounds of cadmium, selenium, and tellurium, compounds of indium, gallium, and arsenic, compounds of indium, gallium, and selenium, compounds of indium, selenium, and sulfur, compounds of copper, indium, and sulfur, and combinations thereof. In addition, so-called alloy-type quantum dots, whose composition is expressed in any ratio, can be used.

[0219] Examples of quantum dot structures include core-type, core-shell-type, and core-multishell-type structures. Furthermore, because quantum dots have a high proportion of surface atoms, they are highly reactive and prone to aggregation. Therefore, to prevent aggregation and improve dispersibility in the dispersion medium, it is preferable that a protective agent is attached to the surface of the quantum dots, or that protective groups are provided. This can also reduce reactivity and improve electrical stability.

[0220] As the size of a quantum dot decreases, its band gap increases, so its size is adjusted appropriately to obtain light of a desired wavelength. As the size decreases, the emission of quantum dots shifts towards the blue side, that is, towards higher energy, so by changing the size of the quantum dots, the emission wavelength can be adjusted across the ultraviolet, visible, and infrared spectral wavelength ranges. The size (diameter) of a quantum dot is, for example, 0.5 nm to 20 nm, preferably 1 nm to 10 nm. Furthermore, the narrower the size distribution of quantum dots, the narrower the emission spectrum becomes, and the better the color purity of the emission can be obtained. The shape of the quantum dots is not particularly limited and may be spherical, rod-shaped, disc-shaped, or other shapes. A quantum rod, which is a rod-shaped quantum dot, has the function of exhibiting directional light.

[0221] Examples of display devices using liquid crystal elements include transmissive liquid crystal display devices, reflective liquid crystal display devices, and semi-transmissive liquid crystal display devices.

[0222] Examples of light-emitting devices include self-emissive light-emitting devices such as LEDs (Light Emitting Diodes), OLEDs, and semiconductor lasers. For example, mini-LEDs and micro-LEDs can be used as LEDs.

[0223] The light-emitting device can emit light in the following colors: infrared, red, green, blue, cyan, magenta, yellow, or white. Furthermore, the color purity can be improved by adding a microcavity structure to the light-emitting device.

[0224] In a light-emitting device, one of the pair of electrodes functions as the anode, and the other electrode functions as the cathode.

[0225] Furthermore, a display device according to one aspect of the present invention may be any of the following: a top-emission type that emits light in the direction opposite to the substrate on which the light-emitting device is formed; a bottom-emission type that emits light toward the substrate on which the light-emitting device is formed; or a dual-emission type that emits light on both sides.

[0226] One embodiment of the present invention is a semiconductor device having a transistor with a high on-current. A suitable material for the channel formation region of the transistor can be an oxide semiconductor (OS), resulting in a transistor with a low off-current. This semiconductor device can be suitably used in either or both of the display unit 162 and the circuit unit 164. Furthermore, this semiconductor device can be used in both the display unit 162 and the circuit unit 164, meaning all transistors in the display device can be OS transistors. By using OS transistors for all transistors in the display device in this way, manufacturing costs can be kept low.

[0227] Figure 15A shows an example of a cross-section of the display device 500A when a portion of the area including the FPC 172, a portion of the circuit section 164, a portion of the display section 162, a portion of the connection section 140, and a portion of the area including the end are cut.

[0228] The display device 500A shown in Figure 15A has transistors 205D, 205R, 205G, 205B, light-emitting devices 130R, 130G, and 130B between substrates 151 and 152. Light-emitting device 130R is a display element of a sub-pixel 11R that emits red light, light-emitting device 130G is a display element of a sub-pixel 11G that emits green light, and light-emitting device 130B is a display element of a sub-pixel 11B that emits blue light.

[0229] The display device 500A employs an SBS structure. Because the SBS structure allows for the optimization of materials and configurations for each light-emitting device, it increases the freedom of material and configuration selection, making it easier to improve brightness and reliability.

[0230] The display device 500A is a top-emission type. In the top-emission type, transistors and the like can be arranged overlapping with the light-emitting region of the light-emitting device, which allows for a higher pixel aperture ratio compared to the bottom-emission type.

[0231] Transistors 205D, 205R, 205G, and 205B are all formed on the substrate 151. Transistor 205D is provided in the circuit section 164, while transistors 205R, 205G, and 205B are provided in the display section 162. These transistors can be manufactured using the same process. Note that transistors with different structures can also be used for transistors 205D, 205R, 205G, and 205B.

[0232] This embodiment shows an example in which OS transistors are used for transistors 205D, 205R, 205G, and 205B. Transistors according to one aspect of the present invention can be used for transistors 205D, 205R, 205G, and 205B. In other words, the display device 500A has transistors according to one aspect of the present invention in both the display unit 162 and the circuit unit 164. By using transistors according to one aspect of the present invention in the display unit 162, the pixel size can be reduced and high resolution can be achieved. Furthermore, by using transistors according to one aspect of the present invention in the circuit unit 164, the occupied area of ​​the circuit unit 164 can be reduced and the bezel can be narrowed. For details on transistors according to one aspect of the present invention, refer to the description of the previous embodiment.

[0233] Figure 15A shows an example configuration in which transistor 210, as shown in Figure 19B and later described, is applied to transistors 205D, 205R, 205G, and 205B. By using TGSA type transistors, the parasitic capacitance between the source electrode, drain electrode, and gate electrode can be reduced. Therefore, the deterioration of display quality caused by parasitic capacitance can be suppressed.

[0234] Transistors 205D, 205R, 205G, and 205B each have a conductive layer 104 functioning as a first gate, a conductive layer 103 functioning as a second gate electrode, an insulating layer 106 functioning as a first gate insulating layer, a second gate insulating layer 105, conductive layers 112a and 112b functioning as source and drain electrodes, and a semiconductor layer 108 having a metal oxide. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film.

[0235] The semiconductor layer 108 preferably has a metal oxide (also called an oxide semiconductor) that exhibits semiconductor properties. The band gap of the metal oxide in the semiconductor layer 108 is preferably 2.0 eV or more, and more preferably 2.5 eV or more. Transistors using oxide semiconductors (hereinafter also referred to as OS transistors) have extremely high field-effect mobility compared to transistors using amorphous silicon. Furthermore, OS transistors have a remarkably small off-current and can retain the charge stored in a capacitor connected in series with the transistor for a long period of time. In addition, by applying OS transistors, the power consumption of semiconductor devices can be reduced. When an oxide semiconductor is used for the semiconductor layer, the semiconductor layer can be called an oxide semiconductor layer or a metal oxide layer.

[0236] For example, silicon can be used for the semiconductor layer 108. Examples of silicon include single-crystal silicon, polycrystalline silicon, microcrystalline silicon, and amorphous silicon. An example of polycrystalline silicon is low-temperature polysilicon (LTPS). Transistors using amorphous silicon for the channel formation region can be formed on a large glass substrate and can be manufactured at low cost. Transistors using polycrystalline silicon for the channel formation region have high field-effect mobility and can operate at high speed. Transistors using microcrystalline silicon for the channel formation region have higher field-effect mobility than transistors using amorphous silicon and can operate at high speed. Note that transistors using silicon for the channel formation region are sometimes referred to as Si transistors, and transistors using LTPS for the channel formation region are sometimes referred to as LTPS transistors.

[0237] Furthermore, the transistors in the display device of this embodiment are not limited to those of one aspect of the present invention. For example, the transistors of one aspect of the present invention may be combined with transistors of other structures.

[0238] The display device of this embodiment may have, for example, one or more of planar transistors, staggered transistors, or inverse staggered transistors. The transistors in the display device of this embodiment may be top-gate or bottom-gate types. Alternatively, gates may be provided above and below the semiconductor layer in which the channel is formed.

[0239] The display device of this embodiment may also have Si transistors.

[0240] To increase the luminescence brightness of a light-emitting device included in a pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, the source-drain voltage of the drive transistor included in the pixel circuit must be increased. Compared to Si transistors, OS transistors have a higher breakdown voltage between their source and drain, allowing a higher voltage to be applied to the source-drain of an OS transistor. Therefore, by using an OS transistor as the drive transistor in the pixel circuit, the amount of current flowing through the light-emitting device can be increased, thereby increasing the luminescence brightness of the light-emitting device.

[0241] When a transistor operates in the saturation region, an OS transistor exhibits a smaller change in source-drain current in response to a change in gate-source voltage than a Si transistor. Therefore, by using an OS transistor as the driving transistor in a pixel circuit, the current flowing between the source and drain can be precisely controlled by the change in gate-source voltage, thereby controlling the amount of current flowing to the light-emitting device. This allows for an increase in the number of grayscale levels in the pixel circuit.

[0242] In terms of the saturation of the current flowing when a transistor operates in the saturation region, OS transistors can supply a more stable current (saturation current) than Si transistors, even when the source-drain voltage gradually increases. Therefore, by using an OS transistor as a driving transistor, a stable current can be supplied to a light-emitting device even if there are variations in the current-voltage characteristics of the light-emitting device. In other words, when operating in the saturation region, OS transistors can stabilize the luminescence brightness of a light-emitting device because the change in source-drain current is small even when the source-drain voltage is changed.

[0243] The transistors in the circuit unit 164 and the transistors in the display unit 162 may have the same structure or different structures. The structures of the multiple transistors in the circuit unit 164 may all be the same or there may be two or more different structures. Similarly, the structures of the multiple transistors in the display unit 162 may all be the same or there may be two or more different structures.

[0244] All of the transistors in the display unit 162 may be OS transistors, all of the transistors in the display unit 162 may be Si transistors, or some of the transistors in the display unit 162 may be OS transistors and the rest may be Si transistors.

[0245] For example, by using both an LTPS transistor and an OS transistor in the display unit 162, a display device with low power consumption and high driving capability can be realized. Furthermore, a configuration combining an LTPS transistor and an OS transistor is sometimes referred to as LTPO. A more preferable example is a configuration in which an OS transistor is used for transistors that function as switches to control conduction and non-conduction between wires, and an LTPS transistor is used for transistors that control current.

[0246] For example, one of the transistors in the display unit 162 functions as a transistor for controlling the current flowing to the light-emitting device, and can also be called a drive transistor. One of the source and drain of the drive transistor is connected to the pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor for the drive transistor. This makes it possible to increase the current flowing to the light-emitting device in the pixel circuit.

[0247] On the other hand, the other transistor in the display unit 162 functions as a switch for controlling the selection and deselection of pixels, and can also be called a selection transistor. The gate of the selection transistor is connected to the gate line, and one of the source and drain is connected to the source line (signal line). It is preferable to use an OS transistor for the selection transistor. This makes it possible to maintain the gradation of pixels even when the refresh rate is significantly low (for example, 1 Hz or less), and thus power consumption can be reduced by stopping the driver when displaying still images.

[0248] An insulating layer 218 is provided so as to cover transistors 205D, 205R, 205G, and 205B. As mentioned above, the insulating layer 218 can be an inorganic insulating layer, an organic insulating layer, or both. Preferably, the insulating layer 218 has an organic insulating layer that functions as a planarizing layer. Alternatively, the insulating layer 218 can have a laminated structure of an organic insulating layer and an inorganic insulating layer. Preferably, the outermost layer of the insulating layer 218 functions as an etching protection layer. An inorganic insulating layer can be suitably used as the etching protection layer. This makes it possible to suppress the formation of recesses in the insulating layer 218 when processing the pixel electrodes 111R, 111G, and 111B. Alternatively, recesses may be provided in the insulating layer 218 when processing the pixel electrodes 111R, 111G, and 111B. Note that the pixel electrodes 111R, 111G, and 111B are sometimes collectively referred to as the pixel electrode 111.

[0249] Light-emitting devices 130R, 130G, and 130B are provided on the insulating layer 218.

[0250] The light-emitting device 130R includes a pixel electrode 111R on an insulating layer 218, an EL layer 113R on the pixel electrode 111R, and a common electrode 115 on the EL layer 113R. The light-emitting device 130R shown in Figure 15A emits red light (R). The EL layer 113R has a light-emitting layer that emits red light.

[0251] The light-emitting device 130G includes a pixel electrode 111G on an insulating layer 218, an EL layer 113G on the pixel electrode 111G, and a common electrode 115 on the EL layer 113G. The light-emitting device 130G shown in Figure 15A emits green light (G). The EL layer 113G has a light-emitting layer that emits green light.

[0252] The light-emitting device 130B includes a pixel electrode 111B on an insulating layer 218, an EL layer 113B on the pixel electrode 111B, and a common electrode 115 on the EL layer 113B. The light-emitting device 130B shown in Figure 15A emits blue light (B). The EL layer 113B has a light-emitting layer that emits blue light.

[0253] In Figure 15A, EL layers 113R, 113G, and 113B are all shown to be the same thickness, but this is not the only option. The thicknesses of EL layers 113R, 113G, and 113B may be different. For example, it is preferable to set the thickness of EL layers 113R, 113G, and 113B so that the optical path length is such that the light emitted by each layer is intensified. This makes it possible to realize a microcavity structure and improve the color purity of the light emitted from each light-emitting device.

[0254] The pixel electrode 111R is in contact with the conductive layer 112b of the transistor 205R at an opening provided in the insulating layer 218, and is connected to the conductive layer 112b. Similarly, the pixel electrode 111G is connected to the conductive layer 112b of the transistor 205G, and the pixel electrode 111B is connected to the conductive layer 112b of the transistor 205B.

[0255] The ends of the pixel electrodes 111R, 111G, and 111B are covered by an insulating layer 237. The insulating layer 237 functions as a partition. The insulating layer 237 can be provided in a single-layer or multi-layer structure using one or both inorganic insulating materials and / or organic insulating materials. For example, the insulating layer 237 can be made of the same material used for the insulating layer 218. The insulating layer 237 electrically insulates the pixel electrodes from the common electrodes. Furthermore, the insulating layer 237 electrically insulates adjacent light-emitting devices from each other.

[0256] The insulating layer 237 is provided at least on the display unit 162. The insulating layer 237 may be provided not only on the display unit 162, but also on the connection unit 140 and the circuit unit 164. Furthermore, the insulating layer 237 may extend to the ends of the display device 500A.

[0257] The common electrode 115 is a continuous film provided in common to the light-emitting devices 130R, 130G, and 130B. The common electrode 115, which is shared by multiple light-emitting devices, is connected to a conductive layer 123 provided at the connection portion 140. It is preferable to use a conductive layer for the conductive layer 123 that is made of the same material and formed using the same process as the pixel electrodes 111R, 111G, and 111B.

[0258] In a display device according to one aspect of the present invention, among the pixel electrodes and common electrodes, the electrode that extracts light is preferably made of a conductive film that transmits visible light. Furthermore, it is preferable that the electrode that does not extract light is made of a conductive film that reflects visible light.

[0259] A conductive film that transmits visible light may also be used on the electrode that does not extract light. In this case, it is preferable to place the electrode between the reflective layer and the EL layer. In other words, the light emitted from the EL layer may be reflected by the reflective layer and extracted from the display device.

[0260] As the material for forming the pair of electrodes of the light-emitting device, metals, alloys, electrically conductive compounds, and mixtures thereof can be used as appropriate. Specifically, such materials include metals such as aluminum, magnesium, titanium, chromium, manganese, iron, cobalt, nickel, copper, gallium, zinc, indium, tin, molybdenum, tantalum, tungsten, palladium, gold, platinum, silver, yttrium, and neodymium, and alloys containing these in appropriate combinations. Other materials include indium tin oxide (In-Sn oxide, also called ITO), In-Si-Sn oxide (also called ITSO), indium zinc oxide (In-Zn oxide), and In-W-Zn oxide. Furthermore, other materials include aluminum-containing alloys such as aluminum, nickel, and lanthanum alloys (Al-Ni-La), as well as silver-magnesium alloys and silver-containing alloys such as silver-palladium-copper alloys (Ag-Pd-Cu, also written as APC). Other materials include elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (e.g., lithium, cesium, calcium, strontium), rare earth metals such as europium and ytterbium, alloys containing these in appropriate combinations, graphene, and the like.

[0261] It is preferable that the light-emitting device has a microcavity structure. Therefore, it is preferable that one of the pair of electrodes in the light-emitting device is a semitransmissive / semi-reflective electrode that transmits and reflects visible light, and the other is a reflective electrode that reflects visible light. By having a microcavity structure in the light-emitting device, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby strengthening the light emitted from the light-emitting device.

[0262] The light transmittance of the transparent electrode shall be 40% or more. For example, it is preferable to use an electrode with a visible light transmittance (light with a wavelength of 400 nm or more and less than 750 nm) of 40% or more for the transparent electrode of a light-emitting device. The visible light reflectance of the semi-transparent and semi-reflective electrodes shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. Furthermore, the electrical resistivity of these electrodes shall be 1 × 10⁻⁶ −２ A value of Ωcm or less is preferable.

[0263] The EL layers 113R, 113G, and 113B are each provided in an island-like manner. In Figure 15A, the edges of adjacent EL layers 113R and 113G overlap, the edges of adjacent EL layers 113G and 113B overlap, and the edges of adjacent EL layers 113R and 113B overlap. When forming island-like EL layers using a fine metal mask, the edges of adjacent EL layers may overlap as shown in Figure 15A, but this is not limited to this. In other words, adjacent EL layers may not overlap and may be separated from each other. Furthermore, in a display device, there may be both regions where adjacent EL layers overlap and regions where adjacent EL layers do not overlap and are separated.

[0264] Each of the EL layers 113R, 113G, and 113B has at least one light-emitting layer. The light-emitting layer has one or more types of light-emitting materials. As the light-emitting material, a material that exhibits a light-emitting color such as blue, purple, blue-violet, green, yellow-green, yellow, orange, or red can be used as appropriate. In addition, a material that emits near-infrared light can also be used as the light-emitting material.

[0265] Examples of luminescent materials include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and inorganic compounds (such as quantum dot materials).

[0266] Examples of quantum dot materials include colloidal quantum dots, alloy quantum dots, core-shell quantum dots, and core quantum dots. Furthermore, quantum dot materials containing elemental groups of Group 2 and Group 16, Group 13 and Group 15, Group 13 and Group 17, Group 11 and Group 17, or Group 14 and Group 15 can be used. Alternatively, quantum dot materials containing elements such as cadmium (Cd), selenium (Se), zinc (Zn), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium (Ga), arsenic (As), and aluminum (Al) can be used.

[0267] The light-emitting layer may contain one or more types of organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). One or more of the organic compounds may be substances with high hole transport properties (hole transport material) and / or substances with high electron transport properties (electron transport material). Alternatively, one or more of the organic compounds may be bipolar substances (substances with high electron and hole transport properties) or TADF materials.

[0268] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting device.

[0269] The EL layer may have, in addition to the light-emitting layer, one or more of the following: a layer containing a material with high hole injection properties (hole injection layer), a layer containing a hole transport material (hole transport layer), a layer containing a material with high electron blocking properties (electron blocking layer), a layer containing a material with high electron injection properties (electron injection layer), a layer containing an electron transport material (electron transport layer), and a layer containing a material with high hole blocking properties (hole blocking layer). Furthermore, the EL layer may contain either or both a bipolar material and a TADF material.

[0270] The light-emitting device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0271] The light-emitting device may be a single structure (a structure having only one light-emitting unit) or a tandem structure (a structure having multiple light-emitting units). Each light-emitting unit has at least one light-emitting layer. The tandem structure is a configuration in which multiple light-emitting units are connected in series via a charge generation layer. The charge generation layer has the function of injecting electrons into one of the two light-emitting units and holes into the other when a voltage is applied between a pair of electrodes. By using a tandem structure, a light-emitting device capable of high-brightness light emission can be made. Furthermore, compared to a single structure, the tandem structure can reduce the current required to obtain the same brightness, thus improving reliability. The tandem structure can also be called a stack structure.

[0272] In Figure 15A, when a tandem light-emitting device is used, it is preferable that the EL layer 113R has a structure having multiple light-emitting units that emit red light, the EL layer 113G has a structure having multiple light-emitting units that emit green light, and the EL layer 113B has a structure having multiple light-emitting units that emit blue light.

[0273] A protective layer 131 is provided covering the light-emitting devices 130R, 130G, and 130B. The protective layer 131 and the substrate 152 are bonded together via an adhesive layer 142. A light-shielding layer 117 is provided on the substrate 152. For sealing the light-emitting devices, for example, a solid sealing structure or a hollow sealing structure can be applied. In Figure 15A, the space between the substrate 152 and the substrate 151 is filled with the adhesive layer 142, and a solid sealing structure is applied. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), and a hollow sealing structure may be applied. In this case, the adhesive layer 142 may be provided in a frame shape so as not to overlap with the light-emitting devices. Alternatively, the space may be filled with a resin different from the adhesive layer 142 provided in a frame shape.

[0274] The protective layer 131 is provided at least on the display section 162, and preferably so as to cover the entire display section 162. It is preferable that the protective layer 131 covers not only the display section 162, but also the connection section 140 and the circuit section 164. Furthermore, it is preferable that the protective layer 131 extends to the edges of the display device 500A. On the other hand, in the connection section 197, there is an area where the protective layer 131 is not provided in order to connect the FPC 172 and the conductive layer 166.

[0275] By providing a protective layer 131 to cover the light-emitting devices 130R, 130G, and 130B, the reliability of the light-emitting devices can be improved.

[0276] The protective layer 131 can be a single layer or a laminated structure of two or more layers. Furthermore, the conductivity of the protective layer 131 is not required. At least one of an insulating film, a semiconductor film, and a conductive film can be used as the protective layer 131.

[0277] The presence of an inorganic film in the protective layer 131 prevents oxidation of the common electrode 115 and suppresses the intrusion of impurities (such as moisture and oxygen) into the light-emitting device. This suppresses the degradation of the light-emitting device and improves the reliability of the display device.

[0278] The protective layer 131 preferably has one or more inorganic insulating layers. The protective layer 131 can be made of the same material that can be used for the insulating layer 106 and the insulating layer 105. In particular, the protective layer 131 preferably uses a nitride or nitride oxide, and more preferably uses a nitride.

[0279] The protective layer 131 may also be an inorganic film containing ITO, In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or IGZO. The inorganic film is preferably highly resistive, and more specifically, it is preferably more resistive than the common electrode 115. The inorganic film may further contain nitrogen.

[0280] When the light emitted from a light-emitting device is extracted via a protective layer 131, it is preferable that the protective layer 131 has high transmittance to visible light. For example, ITO, IGZO, and aluminum oxide are preferred because they are inorganic materials with high transmittance to visible light.

[0281] As the protective layer 131, for example, a laminated structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a laminated structure of an aluminum oxide film and an IGZO film on the aluminum oxide film can be used. By using such a laminated structure, it is possible to suppress the penetration of impurities (water, oxygen, etc.) into the EL layer.

[0282] Furthermore, the protective layer 131 may have an organic layer. For example, the protective layer 131 may have both an organic layer and an inorganic layer. Examples of organic layers that can be used in the protective layer 131 include organic insulating layers that can be used in the insulating layer 218.

[0283] A connection portion 197 is provided in the region of substrate 151 where substrate 152 does not overlap. At the connection portion 197, the conductive layer 165 is connected to the FPC 172 via the conductive layer 166 and the connection layer 242. Figure 15A shows an example in which the conductive layer 165 is formed by processing the same conductive film as conductive layers 112a and 112b. The conductive layer 166 is shown as an example in which it is formed by processing the same conductive film as the pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B. The connection portion between conductive layer 165 and conductive layer 166 can be configured similarly to the connection portion between pixel electrode 111 and conductive layer 112b. Specifically, Figure 15A shows an example in which an opening is provided in the insulating layer 218, and the conductive layer 166 is in contact with the upper surface of the conductive layer 165 at this opening. The conductive layer 166 is exposed on the upper surface of the connection portion 197. This allows the connection part 197 and the FPC 172 to be connected via the connection layer 242.

[0284] The display device 500A is a top-emission type. The light emitted by the light-emitting device is emitted towards the substrate 152. It is preferable to use a material with high transmittance to visible light for the substrate 152. The pixel electrodes 111R, 111G, and 111B contain a material that reflects visible light, and the counter electrode (common electrode 115) contains a material that transmits visible light.

[0285] It is preferable to provide a light-shielding layer 117 on the surface of the substrate 152 that faces the substrate 151. The light-shielding layer 117 can be provided between adjacent light-emitting devices, in connection portions 140, and in circuit portions 164, etc.

[0286] A colored layer, such as a color filter, may be provided on the surface of the substrate 152 facing the substrate 151, or on the protective layer 131. By adding a color filter to the light-emitting device, the color purity of the light emitted from the pixels can be improved.

[0287] A colored layer is a colored layer that selectively transmits light in a specific wavelength range and absorbs light in other wavelength ranges. For example, a red (R) color filter that transmits light in the red wavelength range, a green (G) color filter that transmits light in the green wavelength range, and a blue (B) color filter that transmits light in the blue wavelength range can be used. One or more of the following can be used for each colored layer: metal materials, resin materials, pigments, and dyes. The colored layers are formed at the desired positions using methods such as printing, inkjet printing, and photolithography etching.

[0288] Various optical components can be placed on the outside of the substrate 152 (the side opposite to the substrate 151). Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (such as diffusion films), anti-reflective layers, and light-gathering films. In addition, surface protection layers such as an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and a shock-absorbing layer may be placed on the outside of the substrate 152. For example, a glass layer or a silica layer (SiO ｘ Providing a protective layer (where x is a real number greater than 0) is preferable as it can suppress surface contamination and scratching. Alternatively, DLC (diamond-like carbon), aluminum oxide, polyester-based materials, or polycarbonate-based materials may be used as the surface protective layer. It is preferable to use a material with high transmittance to visible light for the surface protective layer. Furthermore, it is preferable to use a material with high hardness for the surface protective layer.

[0289] The substrates 151 and 152 can be made of glass, quartz, ceramics, sapphire, resin, metal, alloy, semiconductor, etc., respectively. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. If flexible materials are used for substrates 151 and 152, the flexibility of the display device can be increased, and a flexible display can be realized. In addition, a polarizing plate may be used as at least one of substrates 151 and 152.

[0290] As substrates 151 and 152, various materials can be used, such as polyester resins like polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. At least one of substrates 151 and 152 may be made of glass of a thickness sufficient to provide flexibility.

[0291] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence). Examples of films with high optical isotropy include triacetylcellulose (TAC, also called cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0292] Various types of curing adhesives can be used as the adhesive layer 142, including UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0293] As the connecting layer 242, an anisotropic conductive film (ACF), anisotropic conductive paste (ACP), etc., can be used.

[0294] <Example of Display Device Configuration 2> Figure 15B shows an example of a cross-section of the display unit 162 of the display device 500B. The display device 500B differs from the display device 500A in that each sub-pixel of each color uses a light-emitting device having a common EL layer 113 and a coloring layer (such as a color filter). The configuration shown in Figure 15B can be combined with the configuration of the region including the FPC 172, the circuit unit 164, the laminated structure from the substrate 151 to the insulating layer 218 of the display unit 162, the connection unit 140, and the end portion shown in Figure 15A. Note that in the following description of the display device, parts that are the same as those described in the previously described display device may be omitted.

[0295] The display device 500B shown in Figure 15B includes a light-emitting device 130R, a light-emitting device 130G, a light-emitting device 130B, a colored layer 132R that transmits red light, a colored layer 132G that transmits green light, and a colored layer 132B that transmits blue light, etc.

[0296] The light-emitting device 130R includes a pixel electrode 111R and an EL layer 113 on the pixel electrode 111R. The light emitted from the light-emitting device 130R is extracted as red light to the outside of the display device 500B via the colored layer 132R.

[0297] The light-emitting device 130G includes a pixel electrode 111G and an EL layer 113 on the pixel electrode 111G. The light emitted from the light-emitting device 130G is extracted as green light to the outside of the display device 500B via the colored layer 132G.

[0298] The light-emitting device 130B includes a pixel electrode 111B and an EL layer 113 on the pixel electrode 111B. The light emitted from the light-emitting device 130B is extracted as blue light to the outside of the display device 500B via the colored layer 132B.

[0299] The pixel electrode 111R of the light-emitting device 130R, the pixel electrode 111G of the light-emitting device 130G, and the pixel electrode 111B of the light-emitting device 130B each face the common electrode 115 via the EL layer 113. Providing a common EL layer 113 for each sub-pixel of each color reduces the number of manufacturing steps compared to providing a different EL layer for each sub-pixel of each color.

[0300] For example, the light-emitting devices 130R, 130G, and 130B shown in Figure 15B emit white light. The white light emitted by the light-emitting devices 130R, 130G, and 130B passes through the colored layers 132R, 132G, and 132B, thereby obtaining light of a desired color.

[0301] A light-emitting device that emits white light preferably includes two or more light-emitting layers. When obtaining white light emission using two light-emitting layers, the light-emitting layers can be selected such that their emission colors are complementary. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary, a configuration can be obtained in which the entire light-emitting device emits white light. Furthermore, when obtaining white light emission using three or more light-emitting layers, the emission colors of the three or more light-emitting layers combine to create a configuration in which the entire light-emitting device emits white light.

[0302] The EL layer 113 preferably has, for example, an emissive layer having a light-emitting material that emits blue light, and an emissive layer having a light-emitting material that emits visible light with a longer wavelength than blue. The EL layer 113 preferably has, for example, an emissive layer that emits yellow light and an emissive layer that emits blue light. Alternatively, the EL layer 113 preferably has, for example, an emissive layer that emits red light, an emissive layer that emits green light, and an emissive layer that emits blue light.

[0303] For light-emitting devices that emit white light, a tandem structure is preferable. Specifically, a two-stage tandem structure having a light-emitting unit that emits yellow light and a light-emitting unit that emits blue light, a two-stage tandem structure having a light-emitting unit that emits red and green light and a light-emitting unit that emits blue light, a three-stage tandem structure having a light-emitting unit that emits blue light, a light-emitting unit that emits yellow, yellow-green, or green light and a light-emitting unit that emits blue light in that order, or a three-stage tandem structure having a light-emitting unit that emits blue light, a light-emitting unit that emits yellow, yellow-green, or green light and red light and a light-emitting unit that emits blue light in that order. For example, the number of layers and color order of the light-emitting unit can be, from the anode side, a two-layer structure of B and Y, a two-layer structure of B and light-emitting unit X, a three-layer structure of B, Y, B, or a three-layer structure of B, X, B. The number of layers and color order of the light-emitting layers in light-emitting unit X can be, from the anode side, a two-layer structure of R and Y, a two-layer structure of R and G, a two-layer structure of G and R, a three-layer structure of G, R, G, or a three-layer structure of R, G, R. In addition, other layers may be provided between the two light-emitting layers.

[0304] Furthermore, by applying a microcavity structure, a light-emitting device configured to emit white light may also emit light with enhanced emission of specific wavelengths such as red, green, or blue.

[0305] Alternatively, for example, the light-emitting devices 130R, 130G, and 130B shown in Figure 15B emit blue light. In this case, the EL layer 113 has one or more light-emitting layers that emit blue light. In the sub-pixel 11B that emits blue light, the blue light emitted by the light-emitting device 130B can be extracted. Furthermore, in the sub-pixel 11R that emits red light and the sub-pixel 11G that emits green light, by providing a color conversion layer between the light-emitting device 130R or light-emitting device 130G and the substrate 152, the blue light emitted by the light-emitting device 130R or light-emitting device 130G can be converted into longer wavelength light, and red or green light can be extracted. For details on the color conversion layer, please refer to the above description. Specifically, the various quantum dot materials described above can be used for the color conversion layer. Furthermore, it is preferable to provide a colored layer 132R between the color conversion layer and the substrate 152 on the light-emitting device 130R, and a colored layer 132G between the color conversion layer and the substrate 152 on the light-emitting device 130G. Some of the light emitted by the light-emitting device may be transmitted directly without being converted by the color conversion layer. By extracting the light that has passed through the color conversion layer via the colored layer, the colored layer can absorb light other than the desired color, thereby increasing the color purity of the light exhibited by the subpixels.

[0306] <Example of Display Device Configuration 3> The display device 500C shown in Figure 16 differs from the display device 500A in that it has a conductive layer 234p, a conductive layer 234a, a conductive layer 234b, and an insulating layer 239.

[0307] An insulating layer 239 is provided on the conductive layer 234p, conductive layer 234a, conductive layer 234b, and insulating layer 218, and light-emitting devices 130R, 130G, and 130B are provided on the insulating layer 239. The insulating layer 239 can be made from the same materials as those used for the insulating layer 218.

[0308] The conductive layer 234p is provided so as to cover the opening provided in the insulating layer 218. The conductive layer 234p is in contact with the conductive layer 112b of the transistor 205R at the opening and is connected to the conductive layer 112b.

[0309] The pixel electrode 111R is provided so as to cover an opening in the insulating layer 239. The pixel electrode 111R is in contact with the conductive layer 234p at the opening and is connected to the conductive layer 234p. In other words, the pixel electrode 111R is connected to the conductive layer 112b via the conductive layer 234p. The same applies to the pixel electrode 111G and the pixel electrode 111B.

[0310] The conductive layer 234a is provided so as to cover the opening provided in the insulating layer 218. The conductive layer 234a is in contact with the conductive layer 165 at the opening and is connected to the conductive layer 165.

[0311] The conductive layer 166 is provided so as to cover the opening provided in the insulating layer 239. The conductive layer 166 is in contact with the conductive layer 234a at the opening and is connected to the conductive layer 234a. In other words, the conductive layer 166 is connected to the conductive layer 165 via the conductive layer 234a.

[0312] Figure 16 shows a configuration in which the circuit section 164 has a conductive layer 234b. Alternatively, the conductive layer 234b can be connected to the transistor 205D.

[0313] The conductive layers 234p, 234a, and 234b can be formed by processing the same conductive film. Furthermore, each of the conductive layers 234p, 234a, and 234b functions as wiring. The conductive layers 234p, 234a, and 234b are provided on different layers from the conductive layers 112a, 112b, 104, and 103. Therefore, since wiring can be arranged on each layer, the degree of layout flexibility is increased, and the circuit's occupied area can be reduced.

[0314] The conductive layers 234p, 234a, and 234b can be made from the materials listed for conductive layers 112a, 112b, and 104. The conductive layers 234p, 234a, and 234b can be formed in the same process. For example, the conductive layers 234p, 234a, and 234b can be formed by depositing a conductive film and then processing the conductive film.

[0315] <Example of Display Device Configuration 4> The display device 500D shown in Figure 17A differs from the display device 500A mainly in that it has a light receiving device 130S.

[0316] The display device 500D has a light-emitting device and a light-receiving device in each pixel. In the display device 500D, it is preferable to use an organic EL element as the light-emitting device and an organic photodiode as the light-receiving device. The organic EL element and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display device using an organic EL element.

[0317] In a display device 500D having light-emitting and light-receiving devices in its pixels, the pixels have a light-receiving function, allowing for the detection of contact or proximity of an object while displaying an image. Therefore, the display unit 162 has, in addition to an image display function, one or both of an imaging function and a sensing function. For example, not only can the display device 500D display an image using all of its subpixels, but some subpixels can also emit light as a light source, some other subpixels can perform light detection, and the remaining subpixels can display an image.

[0318] Therefore, it is not necessary to provide a light receiving unit and a light source separately from the display device 500D, and the number of components in the electronic device can be reduced. For example, there is no need to separately provide a biometric authentication device or a capacitive touch panel for scrolling, etc., which are installed in the electronic device. Therefore, by using the display device 500D, it is possible to provide an electronic device with reduced manufacturing costs.

[0319] When a light-receiving device is used as an image sensor, the display device 500D can capture images using the light-receiving device. For example, the image sensor can be used to capture images for personal authentication, such as fingerprints, palm prints, irises, pulse patterns (including vein patterns and arterial patterns), or faces.

[0320] The light-receiving device can be used as a touch sensor (also called a direct touch sensor) or a non-contact sensor (also called a hover sensor, hover touch sensor, or touchless sensor). A touch sensor can detect an object (such as a finger, hand, or pen) by making direct contact between the display device and the object. A non-contact sensor can detect an object even if the object does not come into contact with the display device.

[0321] The light-receiving device 130S includes a pixel electrode 111S on an insulating layer 218, a functional layer 113S on the pixel electrode 111S, and a common electrode 115 on the functional layer 113S. Light Lin is incident on the functional layer 113S from outside the display device 500D.

[0322] The pixel electrode 111S is in contact with the conductive layer 112b of the transistor 205S at an opening provided in the insulating layer 218, and is connected to the conductive layer 112b.

[0323] The ends of the pixel electrodes 111S are covered by an insulating layer 237.

[0324] The common electrode 115 is a continuous film shared by the light-receiving device 130S, the light-emitting device 130R (not shown), the light-emitting device 130G, and the light-emitting device 130B. This common electrode 115 is connected to the conductive layer 123 provided at the connection portion 140.

[0325] The functional layer 113S has at least an active layer (also called a photoelectric conversion layer). The active layer contains a semiconductor. Examples of the semiconductor include inorganic semiconductors such as silicon and organic semiconductors containing organic compounds. In this embodiment, an example is shown in which an organic semiconductor is used as the semiconductor of the active layer. Using an organic semiconductor is preferable because the light-emitting layer and the active layer can be formed by the same method (for example, vacuum deposition), and the manufacturing equipment can be shared.

[0326] The functional layer 113S may further include layers other than the active layer, such as a material with high hole transport properties, a material with high electron transport properties, or a bipolar material. Furthermore, it may also further include layers containing a material with high hole injection properties, a hole blocking material, a material with high electron injection properties, or an electron blocking material. For example, the functional layer 113S can be made from materials that can be used in the light-emitting devices described above.

[0327] The light-receiving device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-receiving device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0328] The display device 500D shown in Figures 17B and 17C has a layer 353 having a light-receiving device, a circuit layer 355, and a layer 357 having a light-emitting device between substrates 151 and 152.

[0329] Layer 353 has, for example, a light-receiving device 130S. Layer 357 has, for example, a light-emitting device 130R, a light-emitting device 130G, and a light-emitting device 130B.

[0330] The circuit layer 355 includes a circuit for driving a light-receiving device and a circuit for driving a light-emitting device. The circuit layer 355 includes, for example, transistors 205R, 205G, and 205B. In addition, the circuit layer 355 may be provided with one or more of the following: switches, capacitors, resistors, wiring, and terminals.

[0331] Figure 17B shows an example of using the light-receiving device 130S as a touch sensor. As shown in Figure 17B, the light emitted by the light-emitting device in layer 357 is reflected by the finger 352 that is in contact with the display device 500D, and the light-receiving device in layer 353 detects this reflected light. This makes it possible to detect that the finger 352 has come into contact with the display device 500D.

[0332] Figure 17C shows an example of using the light-receiving device 130S as a non-contact sensor. As shown in Figure 17C, the light emitted by the light-emitting device in layer 357 is reflected by a finger 352 that is close to (i.e., not in contact with) the display device 500D, and the light-receiving device in layer 353 detects the reflected light.

[0333] <Example of Display Device Configuration 5> The display device 500E shown in Figure 18A is an example of a display device to which an MML (Metal Maskless) structure is applied. In other words, the display device 500E has a light-emitting element manufactured without using a fine metal mask.

[0334] In a display device using an MML structure, island-shaped light-emitting layers in the light-emitting device are formed by depositing a light-emitting layer onto one surface and then processing it using lithography. Therefore, it is possible to realize high-definition display devices or display devices with high aperture ratios, which were previously difficult to achieve. Furthermore, since the light-emitting layers can be made separately for each color, it is possible to realize a display device that is extremely vivid, has high contrast, and displays high quality. For example, if the display device consists of three types of light-emitting devices: one that emits blue light, one that emits green light, and one that emits red light, three types of island-shaped light-emitting layers can be formed by repeating the deposition of the light-emitting layer and processing by lithography three times.

[0335] Because MML (Multilayer Molded) devices can be manufactured without using a metal mask, they can exceed the resolution limits imposed by the precision required for metal mask alignment. Furthermore, when manufacturing devices without a metal mask, the equipment and cleaning processes associated with metal mask manufacturing are eliminated. Additionally, since the lithography process can utilize equipment common to or similar to that used for transistor manufacturing, there is no need to introduce special equipment for manufacturing MML devices. Thus, MML structures allow for lower manufacturing costs, making them suitable for mass production of devices.

[0336] In a display device to which an MML structure is applied, there is no need to artificially increase the resolution by applying a special pixel arrangement such as a pentile arrangement. Therefore, a display device with high resolution (for example, 500 ppi or more, 1000 ppi or more, 2000 ppi or more, 3000 ppi or more, or 5000 ppi or more) can be realized using a so-called stripe arrangement in which the R, G, and B subpixels are each arranged in one direction.

[0337] By providing a sacrificial layer on the light-emitting layer, damage to the light-emitting layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting device.

[0338] By employing a film deposition process using an area mask and a processing process using a resist mask, light-emitting devices can be fabricated using a relatively simple process.

[0339] Note that the laminated structure from substrate 151 to insulating layer 218, and the laminated structure from protective layer 131 to substrate 152 are the same as those of the display device 500A, so their explanation will be omitted.

[0340] In Figure 18A, light-emitting devices 130R, 130G, and 130B are provided on the insulating layer 218.

[0341] The light-emitting device 130R includes a conductive layer 124R on an insulating layer 218, a conductive layer 126R on the conductive layer 124R, a layer 133R on the conductive layer 126R, a common layer 114 on the layer 133R, and a common electrode 115 on the common layer 114. The light-emitting device 130R shown in Figure 18A emits red light (R). Layer 133R has a light-emitting layer that emits red light. In the light-emitting device 130R, layer 133R and the common layer 114 can be collectively called the EL layer. In addition, one or both of the conductive layer 124R and the conductive layer 126R can be called the pixel electrode.

[0342] The light-emitting device 130G includes a conductive layer 124G on an insulating layer 218, a conductive layer 126G on the conductive layer 124G, a layer 133G on the conductive layer 126G, a common layer 114 on the layer 133G, and a common electrode 115 on the common layer 114. The light-emitting device 130G shown in Figure 18A emits green light (G). Layer 133G has a light-emitting layer that emits green light. In the light-emitting device 130G, layer 133G and the common layer 114 can be collectively called the EL layer. In addition, one or both of the conductive layer 124G and the conductive layer 126G can be called the pixel electrode.

[0343] The light-emitting device 130B includes a conductive layer 124B on an insulating layer 218, a conductive layer 126B on the conductive layer 124B, a layer 133B on the conductive layer 126B, a common layer 114 on the layer 133B, and a common electrode 115 on the common layer 114. The light-emitting device 130B shown in Figure 18A emits blue light (B). Layer 133B has a light-emitting layer that emits blue light. In the light-emitting device 130B, layer 133B and the common layer 114 can be collectively called the EL layer. In addition, one or both of the conductive layer 124B and the conductive layer 126B can be called the pixel electrode.

[0344] In this specification, among the EL layers of a light-emitting device, layers provided in an island-like manner for each light-emitting device are referred to as layer 133B, layer 133G, or layer 133R, and a layer shared by multiple light-emitting devices is referred to as the common layer 114. In this specification, the common layer 114 may be omitted, and layers 133R, 133G, and 133B may be referred to as island-like EL layers, island-shaped EL layers, etc. Furthermore, light-emitting devices manufactured without using a metal mask do not need to have a common layer, and all layers constituting the EL layer may be formed in an island-like manner.

[0345] Layers 133R, 133G, and 133B are separated from each other. By providing the EL layers in an island-like configuration for each light-emitting device, leakage current between adjacent light-emitting devices can be suppressed. This prevents unintended light emission caused by crosstalk, enabling the realization of a display device with extremely high contrast.

[0346] In Figure 18A, layers 133R, 133G, and 133B are all shown to be of the same thickness, but this is not the only option. The thicknesses of layers 133R, 133G, and 133B may be different.

[0347] The conductive layer 124R is connected to the conductive layer 112b of transistor 205R at an opening provided in the insulating layer 218. Similarly, the conductive layer 124G is connected to the conductive layer 112b of transistor 205G, and the conductive layer 124B is connected to the conductive layer 112b of transistor 205B.

[0348] The conductive layer 124R, conductive layer 124G, and conductive layer 124B are formed to cover the openings provided in the insulating layer 218. Layer 128 is embedded in the recesses of conductive layer 124R, conductive layer 124G, and conductive layer 124B, respectively.

[0349] Layer 128 has the function of flattening the recesses of conductive layers 124R, 124G, and 124B. Conductive layers 126R, 126G, and 126B are provided on conductive layers 124R, 124G, and 124B, respectively, and are connected to conductive layers 124R, 124G, and 124B. Therefore, regions overlapping with the recesses of conductive layers 124R, 124G, and 124B can also be used as light-emitting regions, thereby increasing the aperture ratio of the pixels. It is preferable to use conductive layers that function as reflective electrodes for conductive layers 126R, 126G, and 126B.

[0350] Layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used for layer 128 as appropriate. In particular, it is preferable that layer 128 be formed using an insulating material, and especially preferable that it be formed using an organic insulating material. For example, an organic insulating material that can be used for the insulating layer 237 described above can be applied to layer 128.

[0351] Figure 18A shows an example in which the upper surface of layer 128 has a flat portion, but the shape of layer 128 is not particularly limited. The upper surface of layer 128 can have at least one of a convex curved surface, a concave curved surface, and a flat surface.

[0352] The height of the top surface of layer 128 and the height of the top surface of conductive layer 124R may be the same, approximately the same, or different from each other. For example, the height of the top surface of layer 128 may be lower or higher than the height of the top surface of conductive layer 124R.

[0353] The end of the conductive layer 126R may be aligned with the end of the conductive layer 124R, or it may cover the side surface of the end of the conductive layer 124R. Preferably, the ends of the conductive layer 124R and the conductive layer 126R have a tapered shape. Specifically, it is preferable that the ends of the conductive layer 124R and the conductive layer 126R have a tapered shape with a taper angle greater than 0 degrees and less than 90 degrees. When the end of the pixel electrode has a tapered shape, the layer 133R provided along the side surface of the pixel electrode has an inclined portion. By making the side surface of the pixel electrode tapered, the coverage of the EL layer provided along the side surface of the pixel electrode can be improved.

[0354] Detailed explanations of conductive layers 124G, 126G, and conductive layers 124B, 126B are omitted as they are the same as conductive layers 124R, 126R.

[0355] The top and sides of the conductive layer 126R are covered by layer 133R. Similarly, the top and sides of the conductive layer 126G are covered by layer 133G, and the top and sides of the conductive layer 126B are covered by layer 133B. Therefore, the entire region where conductive layers 126R, 126G, and 126B are provided can be used as the light-emitting region of light-emitting devices 130R, 130G, and 130B, thereby increasing the aperture ratio of the pixels.

[0356] The upper surfaces and sides of layers 133R, 133G, and 133B are covered by insulating layers 125 and 127, respectively. A common layer 114 is provided on layers 133R, 133G, 133B, insulating layer 125, and insulating layer 127, and a common electrode 115 is provided on the common layer 114. Here, the common layer 114 and the common electrode 115 are continuous films provided in common to multiple light-emitting devices.

[0357] In Figure 18A, the insulating layer 237 shown in Figure 15A, etc., is not provided between the conductive layer 126R and layer 133R. Similarly, the insulating layer 237 is not provided between the conductive layer 126G and layer 133G, nor between the conductive layer 126B and layer 133B. In other words, the display device 500E does not have an insulating layer (also called a partition, bank, spacer, etc.) that is in contact with the pixel electrodes and covers the upper edges of the pixel electrodes. Therefore, the distance between adjacent light-emitting devices can be made extremely short. This makes it possible to create a high-definition or high-resolution display device. In addition, since a mask for forming the insulating layer is not required, the manufacturing cost of the display device can be reduced.

[0358] As described above, layers 133R, 133G, and 133B each have an emissive layer. Preferably, layers 133R, 133G, and 133B each have one or both of a carrier transport layer (electron transport layer or hole transport layer) and a carrier block layer (hole block layer or electron block layer) on the emissive layer. When the surfaces of layers 133R, 133G, and 133B are exposed to the atmosphere during the manufacturing process of the display device, providing one or both of the carrier transport layer and the carrier block layer on the emissive layer prevents the emissive layer from being exposed to the atmosphere on the outermost surface. This reduces damage to the emissive layer and improves the reliability of the light-emitting device.

[0359] The common layer 114 may have, for example, an electron injection layer or a hole injection layer. Alternatively, the common layer 114 may have a laminated structure of an electron transport layer and an electron injection layer, or a laminated structure of a hole transport layer and a hole injection layer. The common layer 114 is shared by the light-emitting devices 130R, 130G, and 130B.

[0360] Each side of layer 133R, layer 133G, and layer 133B is covered by the insulating layer 125. In addition, the insulating layer 127 covers each side of layer 133R, layer 133G, and layer 133B with the insulating layer 125 in between.

[0361] The sides of layers 133R, 133G, and 133B are covered by insulating layers 125 and 127, thereby preventing the common layer 114 or common electrode 115 from coming into contact with the pixel electrode. Furthermore, contact between the common layer 114 or common electrode 115 and the sides of layers 133R, 133G, and 133B can be prevented. This suppresses short circuits in the light-emitting device, thereby improving the reliability of the light-emitting device.

[0362] Preferably, the insulating layer 125 has regions that are in contact with the respective sides of layers 133R, 133G, and 133B. By configuring the insulating layer 125 to be in contact with layers 133R, 133G, and 133B, peeling of the layers 133R, 133G, and 133B can be prevented, thereby improving the reliability of the light-emitting device.

[0363] The insulating layer 127 is provided on the insulating layer 125 so as to fill any recesses in the insulating layer 125. Preferably, the insulating layer 127 covers at least a portion of the side surface of the insulating layer 125.

[0364] By providing insulating layers 125 and 127, the gaps between adjacent island-shaped layers can be filled, thereby reducing the large height differences and irregularities on the formed surface of layers (e.g., carrier injection layers and common electrodes) on the island-shaped layers, making it flatter. Consequently, the coverage of the carrier injection layers and common electrodes can be improved.

[0365] The common layer 114 and common electrode 115 are provided covering layers 133R, 133G, 133B, insulating layer 125, and insulating layer 127. Before the insulating layers 125 and 127 are provided, a step difference exists due to the region where the pixel electrode and island-shaped EL layer are provided and the region where the pixel electrode and island-shaped EL layer are not provided (the region between light-emitting devices). In one embodiment of the present invention, the presence of the insulating layers 125 and 127 can flatten this step difference and improve the coverage of the common layer 114 and common electrode 115. Therefore, connection failures due to step breaks can be suppressed. In addition, it is possible to suppress the local thinning of the common electrode 115 due to the step difference, which would increase its electrical resistance.

[0366] The upper surface of the insulating layer 127 is preferably flat. The upper surface of the insulating layer 127 may also be a shape that includes at least one of a flat surface, a convex surface, and a concave surface. For example, the upper surface of the insulating layer 127 is preferably a convex surface with a large radius of curvature.

[0367] The insulating layer 125 can be a single-layer structure or a laminated structure of two or more layers. Preferably, the insulating layer 125 has one or more inorganic insulating layers. The insulating layer 125 can be made of the same material that can be used for the insulating layer 106 and insulating layer 105. In particular, aluminum oxide is preferred because it has a high selectivity ratio with the EL layer during etching and has the function of protecting the EL layer during the formation of the insulating layer 127. In particular, by applying an inorganic insulating film such as an aluminum oxide film, hafnium oxide film, or silicon oxide film formed by the ALD method to the insulating layer 125, an insulating layer 125 with fewer pinholes and excellent function in protecting the EL layer can be formed. Alternatively, the insulating layer 125 may be a laminated structure of a film formed by the ALD method and a film formed by the sputtering method. For example, the insulating layer 125 may be a laminated structure of an aluminum oxide film formed by the ALD method and a silicon nitride film formed by the sputtering method.

[0368] Preferably, the insulating layer 125 functions as a barrier film against at least one of water and oxygen. Preferably, the insulating layer 125 has the function of suppressing the diffusion of at least one of water and oxygen. Furthermore, preferably, the insulating layer 125 has the function of capturing or fixing (getting) at least one of water and oxygen.

[0369] The insulating layer 125 functions as a barrier film, thereby suppressing the intrusion of impurities (typically at least one of water and oxygen) that could diffuse from the outside into each light-emitting device. This configuration makes it possible to provide highly reliable light-emitting devices and, furthermore, highly reliable display devices.

[0370] The insulating layer 127, provided on the insulating layer 125, has the function of flattening the large height differences and irregularities in the insulating layer 125 formed between adjacent light-emitting devices. In other words, the presence of the insulating layer 127 has the effect of improving the flatness of the surface forming the common electrode 115.

[0371] As the insulating layer 127, an insulating layer having an organic material can be suitably used. Preferably, a photosensitive resin is used as the organic material; for example, a photosensitive resin composition containing an acrylic resin is preferred. In this specification, the term "acrylic resin" does not refer only to polymethacrylate esters or methacrylic resins, but may refer to acrylic polymers in a broad sense.

[0372] As the insulating layer 127, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins may be used. Alternatively, as the insulating layer 127, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used. Furthermore, a photoresist may be used as the photosensitive resin. Either a positive-type or negative-type material may be used as the photosensitive resin.

[0373] The insulating layer 127 may be made of a material that absorbs visible light. By absorbing the light emitted from the light-emitting device, the insulating layer 127 can suppress light leakage (stray light) from the light-emitting device to adjacent light-emitting devices through the insulating layer 127. This improves the display quality of the display device. Furthermore, since the display quality can be improved without using a polarizing plate in the display device, the display device can be made lighter and thinner.

[0374] Examples of materials that absorb visible light include materials containing pigments such as black, materials containing dyes, light-absorbing resin materials (e.g., polyimide resin), and resin materials that can be used in color filters (color filter materials). In particular, it is preferable to use a resin material which is made by laminating or mixing two or more color filter materials, as this can enhance the visible light shielding effect. In particular, by mixing three or more color filter materials, it is possible to create a black or near-black resin layer.

[0375] <Example of Display Device Configuration 6> Figure 18B shows an example of a cross-section of the display unit 162 of the display device 500F. The display device 500F differs from the display device 500E in that each of the red, green, and blue subpixels is provided with a coloring layer (such as a color filter). The configuration shown in Figure 18B can be combined with the configuration shown in Figure 18A, which includes the region containing the FPC 172, the circuit unit 164, the laminated structure from the substrate 151 to the insulating layer 218 of the display unit 162, the connection unit 140, and the end.

[0376] The display device 500F shown in Figure 18B includes a light-emitting device 130R, a light-emitting device 130G, a light-emitting device 130B, a colored layer 132R, a colored layer 132G, and a colored layer 132B, etc.

[0377] The light emitted from the light-emitting device 130R is extracted as red light to the outside of the display device 500F via the colored layer 132R. Similarly, the light emitted from the light-emitting device 130G is extracted as green light to the outside of the display device 500F via the colored layer 132G. The light emitted from the light-emitting device 130B is extracted as blue light to the outside of the display device 500F via the colored layer 132B.

[0378] Light-emitting devices 130R, 130G, and 130B each have layers 133R, 133G, and 133B, respectively. Layers 133R, 133G, and 133B are sometimes collectively referred to as layer 133. These three layers 133 are formed using the same material and the same process. Furthermore, these three layers 133 are spaced apart from each other. By providing the EL layer in an island-like configuration for each light-emitting device, leakage current between adjacent light-emitting devices can be suppressed. This prevents unintended light emission caused by crosstalk, enabling the realization of a display device with extremely high contrast.

[0379] For example, the light-emitting devices 130R, 130G, and 130B shown in Figure 18B emit white light. The white light emitted by the light-emitting devices 130R, 130G, and 130B passes through the colored layers 132R, 132G, and 132B, thereby obtaining light of a desired color.

[0380] Alternatively, for example, the light-emitting devices 130R, 130G, and 130B shown in Figure 18B emit blue light. In this case, layer 133 has one or more light-emitting layers that emit blue light. In the sub-pixel 11B that emits blue light, the blue light emitted by the light-emitting device 130B can be extracted. Although not shown, in the sub-pixel 11R that emits red light and the sub-pixel 11G that emits green light, by providing a color conversion layer between the light-emitting device 130R or light-emitting device 130G and the substrate 152, the blue light emitted by the light-emitting device 130R or light-emitting device 130G can be converted into longer wavelength light, and red or green light can be extracted. Furthermore, it is preferable to provide a coloring layer 132R between the color conversion layer and the substrate 152 on the light-emitting device 130R, and a coloring layer 132G between the color conversion layer and the substrate 152 on the light-emitting device 130G. By extracting the light that has passed through the color conversion layer via the colored layer, the colored layer absorbs light of colors other than the desired color, thereby increasing the color purity of the light exhibited by the subpixel.

[0381] [Transistors] In a display device according to one aspect of the present invention, the transistors shown in Figures 19A to 19E can be used as transistors. The transistor shown in Figure 19B is the same as the transistors shown in Figures 15A to 18.

[0382] The transistors 209 and 210 shown in Figures 19A and 19B have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer 231 having a channel forming region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel forming region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel forming region 231i. Furthermore, an insulating layer 218 covering the transistor may be provided.

[0383] In the transistor 209 shown in Figure 19A, an example is shown where the insulating layer 225 covers the top and side surfaces of the semiconductor layer 231. The conductive layers 222a and 222b are connected to the low-resistance region 231n through openings provided in the insulating layers 225 and 215, respectively. Of the conductive layers 222a and 222b, one functions as a source and the other functions as a drain.

[0384] On the other hand, in the transistor 210 shown in Figure 19B, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231, but does not overlap with the low-resistance region 231n. For example, the structure shown in Figure 19B can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In Figure 19B, an insulating layer 215 is provided covering the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and conductive layer 222b are connected to the low-resistance region 231n, respectively, through openings in the insulating layer 215.

[0385] The transistor 205 shown in Figure 19C has a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 that covers the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0386] The transistor 205 employs a configuration in which a semiconductor layer on which a channel is formed is sandwiched between two gates. The transistor may be driven by connecting the two gates and supplying them with the same signal. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential to control the threshold voltage to one of the two gates and a potential to drive the other gate.

[0387] The transistors 206 and 208 shown in Figures 19D and 19E each have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer 231, a conductive layer 222a, and a conductive layer 222b. The conductive layer 222a functions as one of the source and drain, and the conductive layer 222b functions as the other of the source and drain.

[0388] An insulating layer 160 is provided on the conductive layer 222a, and a conductive layer 222b is provided on the insulating layer 160. The conductive layer 222b and the insulating layer 160 have openings that reach the conductive layer 222a. The semiconductor layer 231 is provided so as to cover the openings and is in contact with the conductive layer 222a at the openings. The semiconductor layer 231 is also in contact with the side surfaces of the insulating layer 160 and the conductive layer 222b. Preferably, the semiconductor layer 231 is in contact not only with the side surfaces of the conductive layer 222b but also with the upper surface of the conductive layer 222b. The region of the semiconductor layer 231 in contact with the conductive layer 222a functions as one of the source region and the drain region, and the region in contact with the conductive layer 222b functions as the other of the source region and the drain region. In the semiconductor layer 231, the channel-forming region is located between the source region and the drain region. An insulating layer 211 is provided on a semiconductor layer 231, and a conductive layer 221 is provided on the insulating layer 211. The conductive layer 221 has a region that overlaps with the semiconductor layer 231 via the insulating layer 211 at its opening.

[0389] The insulating layer 160 can be a laminated structure. Figures 19D and 19E show an example configuration in which the insulating layer 160 has an insulating layer 160a, an insulating layer 160b on the insulating layer 160a, and an insulating layer 160c on the insulating layer 160b.

[0390] Transistors 206 and 208 are positioned at different heights relative to the surface of the substrate (for example, at heights perpendicular to the substrate surface or insulating plane on which the transistors are mounted), and the drain current flows perpendicular to the substrate surface, or approximately perpendicular. In other words, the channel length has a component in the height direction (vertical direction), so transistors 206 and 208 can also be called VFETs (Vertical Field Effect Transistors), vertical transistors, vertical channel transistors, or vertical channel type transistors, respectively.

[0391] The channel lengths of transistor 206 and transistor 208 can be controlled by the thickness of the insulating layer (in this case, insulating layer 160) sandwiched between the source electrode and the drain electrode, respectively. Therefore, transistors 206 and 208 with channel lengths shorter than the minimum exposure dimension of the exposure apparatus used to manufacture the transistors can be manufactured with high precision. By shortening the channel lengths of transistor 206 and transistor 208, the on-current can be increased. This makes it possible to create a display device that operates at high speed.

[0392] Transistors 206 and 208 can each be configured with their source electrode, semiconductor layer, and drain electrode stacked on top of each other. Therefore, compared to so-called planar transistors in which these are arranged in a planar manner, the occupied area can be significantly reduced. By applying VFETs to the pixel circuits of a display device, the occupied area of ​​the pixel circuits can be reduced, enabling a high-definition display device. Furthermore, by applying VFETs to the drive circuits of a display device (for example, one or both of the gate line drive circuit and the source line drive circuit), the occupied area of ​​the drive circuits can be reduced, enabling a narrow-bezel display device.

[0393] At least the region of the semiconductor layer 231 that is in contact with the insulating layer 160b functions as the channel formation region of the transistor 206. It is preferable that the insulating layer 160b releases oxygen when heat is applied. This reduces the oxygen deficiency (V) in the channel formation region. Ｏ : Oxygen Vaccine), and oxygen deficiency (V Ｏ A defect in which hydrogen has entered (hereinafter referred to as V Ｏ This can reduce (also written as H). It is preferable to use an oxide insulating film as the insulating layer 160b. For example, a silicon oxide film or a silicon oxide nitride film can be suitably used as the insulating layer 160b.

[0394] The insulating layer 160a and insulating layer 160c function as barrier layers that prevent oxygen from detaching from the insulating layer 160b to the insulating layer 160a side and the insulating layer 160c side, respectively. By sandwiching the insulating layer 160b between the insulating layer 160a and the insulating layer 160c, the amount of oxygen supplied from the insulating layer 160b to the channel formation region can be increased, thereby improving the V of the channel formation region. Ｏ and V Ｏ H can be efficiently reduced. Therefore, a transistor with good electrical characteristics and high reliability can be obtained. The insulating layer 160a and the insulating layer 160c can each be made of a film that is less permeable to hydrogen or oxygen diffusion than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0395] The transistor 208 shown in Figure 19E has an insulating layer 225 that functions as a gate insulating layer and a conductive layer 223 that functions as a gate. Figure 19E shows an example configuration in which the conductive layer 223 is located between the insulating layer 160a and the insulating layer 160b. The insulating layer 160, the conductive layer 223 and the conductive layer 222b have an opening that reaches the conductive layer 222a. The insulating layer 225 is provided along the side wall of the opening. A semiconductor layer 231 is provided on the insulating layer 225. The semiconductor layer 231 has a region sandwiched between the conductive layer 221 via the insulating layer 211 and the conductive layer 223 via the insulating layer 225.

[0396] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part.

[0397] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0398] 13: Support body, 13_1: Deformable body, 13_2: Recovery body, 13A: Support body, 13B: Support body, 13C: Support body, 13TH: Region, 14A: Region, 14B: Region, 14C: Region, 16: Power supply, 17: Heating element, 19: Adhesive layer, 20: Display device, 20X: Display device, 30: Display unit, 31: Housing, 32: Housing, 33: Spacer, 33B: Adhesive layer, 33U: Adhesive layer, 34: Spacer, 34B: Adhesive layer, 3 4U: Adhesive layer, 35: Housing, 40: Foldable device, 41: Rotating plate, 42: Rotating plate, 43: Rotation axis, 44: Rotation axis, 45: Hinge, 46: Hinge, 47: Adhesive layer, 48: Adhesive layer, 49A: Region, 49B: Region, 49C: Region, 51: Folding axis, 51X: Folding axis, 52: Vector, 60: Electronic equipment control unit, 70: Shape recovery system, 71: Heat generation control unit, 81: Rotation angle center 82: Temperature sensor, 83: Timer, 84: Temperature control device, 128: Layer, 131: Protective layer, 133: Layer, 133B: Layer, 133G: Layer, 133R: Layer, 131U: Filler, 131B: Adhesive layer, 142: Adhesive layer, 162: Display unit, 311A: Protective layer, 321A: Protective layer, 353: Layer, 357: Layer, 500A: Display device, 500B: Display device, 500C: Display device, 500D: Display device 500E: Display device, 500F: Display device, 1311: Outer surface, 1321: Inner surface, D1: Length, D2: Length, I13: Length, M1: Point, M2: Point, M3: Point, M4: Point, O13: Length, R: Radius of curvature, RX: Radius of curvature, R13: Diameter of curvature, SM1: Point, SM2: Point, SM3: Point, SM4: Point, SW13: Switch, T13: Thickness

Claims

Flexible display and A support having a shape memory alloy, It has a heating element, The flexible display and the support have a planar region and a curved region when bent. The support is located between the flexible display and the heating element. The heating element has a region that overlaps with the curved region. Display device. 　 In claim 1, The heating element has the function of heating the shape memory alloy to a temperature above its shape recovery temperature. Display device. 　 In claim 1, The curved region of the support includes the shape memory alloy. Display device. 　 The display device according to claim 3, A first housing and a second housing joined to the planar region of the support, It comprises a third housing that joins the first housing and the second housing, The third housing includes a first rotating plate rotatably attached to the first housing and a second rotating plate rotatably attached to the second housing. electronic equipment. 　 In claim 4, The planar region of the support comprises a first region joined to the first housing and a second region joined to the second housing. The curved region of the support is located between the first region and the second region. Display device. 　 Flexible display and A shape memory alloy is provided so as to overlap with the curved portion of the flexible display, A heating element for heating the shape memory alloy, A temperature sensor for measuring the temperature of the heat-generating part, The housing has a rotation angle sensor for detecting the bending angle of the housing, The heating element has the function of heating the shape memory alloy to a temperature above its shape recovery temperature when the rotation angle sensor detects the unfolding of the housing. Display device.

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