Display device

Abstract

To provide a display device in which a damage of a flexible display is prevented and mechanical strength is increased.SOLUTION: A display device includes a display panel and a protection cover. The display panel has a first part with flexibility. The protection cover has a light-transmitting property and flexibility, and is provided overlapping with a display surface side of the display panel. The display device has a function of being reversibly deformed into a first mode in which the display panel and the protection cover are substantially flat, and a second mode in which the first part of the display panel is bent so that the display surface side becomes a concave curved surface and a part of the protection cover is bent in the same direction as the first part. In the second mode, there is a gap between the first part and the protection cover.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] One aspect of the present invention relates to a display device. In particular, it relates to a display device including a flexible display.

[0002] Note that one aspect of the present invention is not limited to the above technical field. Examples of the technical field of one aspect of the present invention disclosed in this specification and the like include semiconductor devices, display devices, light-emitting devices, power storage devices, storage devices, electronic devices, lighting devices, input devices, input / output devices, their driving methods, or their manufacturing methods. A semiconductor device refers to all devices that can function by utilizing semiconductor characteristics.

Background Art

[0003] The development of flexible displays capable of curving the display surface has been actively carried out. Representative examples of display elements used in flexible displays include light-emitting elements such as organic EL (Electro Luminescence) elements, or liquid crystal elements.

[0004] The basic configuration of an organic EL element is such that a layer containing a light-emitting organic compound is sandwiched between a pair of electrodes. By applying a voltage to this element, light emission can be obtained from the light-emitting organic compound. A display device to which such an organic EL element is applied can realize a thin, lightweight, high-contrast, and low-power consumption display device because a light source such as a backlight is not required.

[0005] For example, Patent Document 1 discloses a flexible light-emitting device to which an organic EL element is applied.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Flexible displays have a problem in that it is difficult to increase mechanical strength because they are extremely thin compared to conventional displays. In particular, when a flexible display functions as a touch panel, if a finger or a stylus touches the display surface strongly, the flexible display may be damaged.

[0008] One aspect of the present invention aims to prevent damage to a flexible display. Or, one aspect of the present invention aims to provide a display device with enhanced mechanical strength. Or, one aspect of the present invention aims to provide a highly reliable display device. Or, one aspect of the present invention aims to provide a display device or an electronic device having a novel configuration.

[0009] Note that the description of these problems does not preclude the existence of other problems. Note that one aspect of the present invention does not necessarily need to solve all of these problems. Note that other problems can be extracted from the descriptions in the specification, drawings, claims, etc.

Means for Solving the Problems

[0010] One aspect of the present invention is a display device including a display panel and a protective cover. The display panel has a first portion having flexibility. The protective cover has translucency and flexibility and is provided so as to overlap the display surface side of the display panel. The display device has a function of reversibly deforming between a first form and a second form. In the first form, the display panel and the protective cover are each substantially flat. In the second form, the first portion of the display panel curves so that the display surface side becomes a concave curved surface, and a part of the protective cover curves in the same direction as the first portion. Also, in the second form, there is a gap between the first portion and the protective cover.

[0011] In addition, in the above, in the first form, it is preferable that the display panel and the protective cover are provided in contact with each other. Alternatively, in the first form, it is preferable that the display panel and the protective cover are provided at a distance from each other.

[0012] In addition, in the above, it is preferable that the protective cover has a function as a touch panel or a circular polarizing plate.

[0013] In addition, in the above, it is preferable to have a functional layer with flexibility between the display panel and the protective cover. At this time, in the second form, it is preferable that a part of the functional layer is curved in the same direction as the first part. Furthermore, it is preferable that the functional layer has a function as a touch panel or a circular polarizing plate.

[0014] In addition, in the above, the display panel has a second part and a third part, the first part is located between the second part and the third part, and in the second form, the second part and the third part are substantially flat, and it is preferable that the region where the part of the protective cover overlapping the second part and the part overlapping the third part are substantially flat.

[0015] In addition, in the above, when the angle formed by the surface of the second part and the surface of the third part is the angle θ, in the range where the angle θ is 90 degrees or more and less than 180 degrees, when the angle θ is gradually decreased from 180 degrees, it is preferable that the protective cover has an angular range in which the distance between the end of the second part or the third part of the display panel and the end of the protective cover continuously increases.

[0016] In addition, in the above, when the angle formed by the surface of the second part and the surface of the third part is the angle θ, in the range where the angle θ is 90 degrees or more and less than 180 degrees, it preferably has an angular range in which the radius of curvature of the first part is smaller than the radius of curvature of the curved part of the protective cover, and in the range where the angle θ is 0 degrees or more and less than 90 degrees, it preferably has an angular range in which the radius of curvature of the first part is larger than the radius of curvature of the curved part of the protective cover.

[0017] Also, in the above, when the angle formed by the surface of the second part and the surface of the third part is defined as angle θ, it is preferable that in the range where angle θ is 90 degrees or more and less than 180 degrees, there is an angular range in which the distance between the first part and the protective cover continuously increases when angle θ is gradually decreased from 180 degrees.

[0018] Also, in the above, when the angle formed by the surface of the second part and the surface of the third part is defined as angle θ, it is preferable that in the range where angle θ is 90 degrees or more and 180 degrees or less, the protective cover is provided with tension in a direction perpendicular to a pair of end portions intersecting the bending direction.

[0019] Also, in the above, it is preferable to have a first support fixed to the second part and a second support fixed to the third part. At this time, it is preferable that the first part is not fixed to either the first support or the second support.

[0020] Also, in the above, among a pair of end portions of the protective cover that intersect the bending direction, it is preferable that one is fixed to the first support and the other is not fixed to either the first support or the second support.

[0021] Also, in the above, it is preferable that the first support has a first rotation axis perpendicular to the bending direction of the second part, and the second support has a second rotation axis parallel to the first rotation axis. At this time, the first support and the second support can rotate in opposite directions and at the same angle around the first rotation axis or the second rotation axis respectively, and it is preferable that the relative positions of the first rotation axis and the second rotation axis do not change.

[0022] Also, in the above, it is preferable that the first support and the second support each have a holding member, and the protective cover is slidably attached to the holding member.

[0023] In addition, in the above, it is preferable that the protective cover contains one or more of urethane resin, acrylic resin, and silicone resin.

Advantages of the Invention

[0024] According to one aspect of the present invention, it is possible to prevent damage to the flexible display. Or, it is possible to provide a display device with enhanced mechanical strength. Or, it is possible to provide a highly reliable display device. Or, it is possible to provide a display device or an electronic device having a novel configuration.

[0025] Note that the description of these effects does not preclude the existence of other effects. Note that one aspect of the present invention does not necessarily have to have all of these effects. Note that other effects can be extracted from the descriptions in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0026]

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DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments can be implemented in many different ways, and it is easily understood by those skilled in the art that the forms and details can be variously changed without departing from the spirit and scope. Therefore, the present invention is not construed as being limited to the description of the following embodiments.

[0028] In the configuration of the invention described below, the same reference numerals are commonly used for the same parts or parts having the same functions among different drawings, and the repeated description thereof is omitted. Also, when referring to the same function, the hatch patterns may be the same, and there may be cases where no particular reference numerals are attached.

[0029] In each of the figures described in this specification, the size of each component, the thickness of each layer, or the area may be exaggerated for clarity. Therefore, it is not necessarily limited to that scale.

[0030] Note that ordinal numbers such as "first" and "second" in this specification and the like are attached to avoid confusion of components and are not numerically limiting.

[0031] In this specification and the like, a display panel, which is an aspect of a display device, has a function of displaying (outputting) an image or the like on a display surface. Therefore, the display panel is an aspect of an output device.

[0032] In this specification and the like, a display panel module, a display module, or simply a display panel may refer to a display panel having a connector such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package) attached to the substrate of the display panel, or a display panel having an IC mounted on the substrate by a COG (Chip On Glass) method or the like.

[0033] Note that in this specification and the like, a touch panel, which is an aspect of a display device, has a function of displaying an image or the like on a display surface and a function as a touch sensor that detects when a detection object such as a finger or a stylus touches, presses, or approaches the display surface. Therefore, the touch panel is an aspect of an input / output device.

[0034] The touch panel can also be referred to as, for example, a display panel (or display device) with a touch sensor or a display panel (or display device) with a touch sensor function. The touch panel can also be configured to have a display panel and a touch sensor panel. Alternatively, it can be configured to have a function as a touch sensor inside or on the surface of the display panel.

[0035] In addition, in this specification and the like, a substrate of a touch panel on which a connector or an IC is mounted may be referred to as a touch panel module, a display module, or simply a touch panel.

[0036] (Embodiment 1) In this embodiment, a configuration example of a display device according to an aspect of the present invention will be described. Hereinafter, a display device having a flexible display panel will be described.

[0037] [Configuration Example] FIG. 1A shows a perspective schematic view of a display device 10. The display device 10 includes a display panel 11, a protective cover 12, a support 21, and a support 22. The display panel 11 has a display portion 15.

[0038] At least a part of the display panel 11 is flexible and can be bent. A plurality of pixels are arranged in a matrix in the display portion 15 of the display panel 11, and an image can be displayed on the display portion 15.

[0039] At least one or more display elements are provided in the pixels provided in the display portion 15 of the display panel 11. As the display element, an organic EL element can typically be used. In addition, various display elements such as inorganic EL elements, light-emitting elements such as LED elements, liquid crystal elements, microcapsules, electrophoretic elements, electro-wetting elements, electro-fluidic elements, electrochromic elements, and MEMS elements can be used.

[0040] The protective cover 12 is located on the display surface side of the display panel 11 and has a function of protecting the surface of the display panel 11. The protective cover 12 has translucency, and the user can view the image displayed on the display portion 15 through the protective cover 12. In addition, at least a part of the protective cover 12 is flexible and can be bent.

[0041] In addition, the protective cover 12 may have functions as a touch sensor panel and as an optical film. When the protective cover 12 functions as a touch sensor panel, the protective cover 12 can be configured to include sensor elements such as a capacitive touch sensor, an optical sensor, and a pressure-sensitive touch sensor. Examples of the optical film include a circularly polarized plate, an anti-reflection film (including an AR (Anti-Reflection) film and an AG (Anti-Glare) film), and the like.

[0042] As the protective cover 12, it is preferable to use a sheet-like member having at least one or more of urethane resin, acrylic resin, silicone resin, fluororesin, olefin resin, vinyl resin, styrene resin, amide resin, ester resin, and epoxy resin. In particular, urethane resin has a relatively high dielectric constant and can enhance the sensitivity when applied to a capacitive touch sensor. In addition, it is preferable because it can impart functions of high lubricity and self-healing properties to the surface of the protective cover 12.

[0043] In particular, when an organic resin having self-healing properties is used as the material located on the outermost surface of the protective cover 12, it is preferable because it can prevent surface scattering caused by scratches and maintain the display quality. In addition, by using a resin having water repellency and oil repellency as the organic resin or performing surface treatment to impart water repellency and oil repellency, it is possible to prevent dirt such as fingerprints from adhering to the surface of the protective cover 12. As materials having self-healing properties, for example, in addition to the urethane resin described above, materials including polyrotaxane, cyclodextrin, polyphenylene ether, and the like can be used. At this time, it is more preferable that the protective cover 12 has a configuration in which the organic resin having self-healing properties is laminated on a sheet made of one or more of the urethane resin, acrylic resin, or silicone resin described above.

[0044] In addition, in order to improve the lubricity of the outermost surface of the protective cover 12, it is preferable to perform coating, surface treatment, or attach a highly lubricious film. Further, not only the display surface side of the protective cover 12 but also the surface on the display panel 11 side is improved in lubricity, so that when the display panel 11 and the protective cover 12 are provided in contact with each other, it is preferable because they are likely to slip.

[0045] The support bodies 21 and 22 have a function of supporting the display panel 11. The support bodies 21 and 22 preferably have a flat surface or a smooth curved surface at least on the surface that supports the display panel 11. Further, it is preferable that the surface has rigidity to such an extent that it does not deform even when pressed by a person's finger or a stylus. For example, it is preferable to use a relatively rigid material such as plastic, glass, metal, alloy, ceramic, or wood for the surfaces of the support bodies 21 and 22 that support the display panel 11.

[0046] The display panel 11 has a portion fixed to the support body 21, a portion fixed to the support body 22, and a portion not fixed to either support body between these two portions. The display panel 11 preferably has flexibility at least in the portion not fixed to the support bodies 21 and 22.

[0047] FIG. 1B shows a perspective schematic view of the display device 10 in a state where the display panel 11 and the protective cover 12 are not curved.

[0048] At this time, the display panel 11 is in a state of being supported by either the support body 21 or the support body 22. Further, a protective cover 12 is provided on the display surface side of the display panel 11. In this state, since the entire display panel 11 is supported by the rigid support bodies 21 and 22, it has high mechanical strength against pressure from the display surface side. At this time, it is preferable that the support body 21 and the support body 22 are in close contact with each other so that gaps or steps are less likely to occur between the respective surfaces (also referred to as joints) that support at least the display panel 11.

[0049] FIG. 1C shows a schematic perspective view of the display device 10 in a state where the display panel 11 and the protective cover 12 are curved. The display panel 11 is curved such that a part on the display surface side is a concave curved surface. Also, the protective cover 12 is curved in the same direction such that a part on the display surface side is a concave curved surface. FIGS. 1D and 1E respectively show enlarged views of regions P and Q in FIG. 1C.

[0050] Here, the direction D of the arrow shown by the dashed line in FIGS. 1B and 1C corresponds to the bending direction of the display panel 11. Here, the case where the display panel 11 is bent is shown such that the long side direction of the display panel 11 coincides with the bending direction. Note that the bending direction is not limited to this, and it may coincide with the short side direction. Also, it may be a direction that is not parallel to any of the sides forming the contour of the display panel 11.

[0051] Region P is a region including the end portions of the curved portions of the display panel 11 and the protective cover 12. Region Q is a region including the end portions of the non-curved portions of the display panel 11 and the protective cover 12.

[0052] As shown in FIGS. 1C and 1D, in the curved portions of the display panel 11 and the protective cover 12, the display panel 11 and the protective cover 12 are separated from each other. That is, it can also be said that there is a gap between the curved portion of the display panel 11 and the protective cover 12.

[0053] Also, as shown in FIGS. 1C and 1E, when the display panel 11 and the protective cover 12 are curved, the protective cover 12 deforms such that the end portion (also referred to as a side) intersecting the bending direction of the protective cover 12 is displaced relatively outward with respect to the end portion of the display panel 11 or the end portion of the support 22.

[0054] In FIGS. 1A to 1E, in order to clearly show the above-described displacement state, in a state where the display panel 11 and the protective cover 12 are not curved (i.e., the state of FIG. 1B), when viewed from above, the respective ends of the display panel 11, the protective cover 12, the support 21, and the support 22 are shown to coincide.

[0055] When the display panel 11 is curved, by deforming the protective cover 12 so as to be displaced relative to the display panel 11, a gap can be provided between the display panel 11 and the protective cover 12 in the curved portion without stretching or contracting either the display panel 11 or the protective cover 12.

[0056] Here, the effect of providing a gap between the protective cover 12 and the curved portion of the display panel 11 will be described with reference to FIGS. 2A and 2B. FIG. 2A is a cross-sectional view along the bending direction when the display panel 11 and the protective cover 12 are in close contact, and FIG. 2B is a cross-sectional view when there is a crescent-shaped gap between them.

[0057] The curved portion of the display panel 11 is deformed so as to float from the support 21 and the support 22, and thus the curved portion is not supported by either the support 21 or the support 22.

[0058] As shown in FIG. 2A, in the portion where the display panel 11 is not curved and is supported by the support 22, even if a thin member (here, the stylus 29) is pushed from the side of the protective cover 12, the pressure can be absorbed by the deformation of the protective cover 12, so that the display panel 11 can be prevented from deforming and being damaged. On the other hand, in the curved portion of the display panel 11, since the back side of the display panel 11 is not supported, the display panel 11 also deforms following the deformation of the protective cover 12. As a result, in the worst case, the display panel 11 may be damaged and the stylus 29 may penetrate.

[0059] However, in one aspect of the present invention, since there is a gap between the protective cover 12 and the display panel 11 at the curved portion of the display panel 11, as shown in FIG. 2B, even when pierced with the stylus 29, the pressure is absorbed by the deformation of the protective cover 12 and does not reach the display panel 11. Therefore, a display device with excellent mechanical strength can be realized.

[0060] Here, the case where the curved portion of the display panel 11 is not supported by the supports 21 and 22 has been described. However, for example, when using a support that can also support the curved portion of the display panel 11 instead of the supports 21 and 22, at least the surface that supports the display panel 11 needs to be deformed or expand and contract. Therefore, the surface of the support that supports the display panel 11 needs to have flexibility or stretchability, and it is difficult to achieve high rigidity. Therefore, when the display panel 11 is pierced from the display surface side, the surface of the support is deformed by the pressure, and the display panel 11 itself may be deformed into a concave shape and may be damaged. Therefore, even in such a configuration, it is extremely effective to provide a gap between the display panel 11 and the protective cover 12 so that they do not contact each other, and to configure the pressure to be absorbed by the deformation of the protective cover 12.

[0061] Here, the laminated structure of the display panel 11 and the protective cover 12 will be described. FIGS. 2C to 2F are enlarged cross-sectional views of the region surrounded by the broken line shown in FIG. 2B.

[0062] FIG. 2C is an example in which the display panel 11 and the protective cover 12 are provided in contact with each other.

[0063] FIG. 2D is an example in which the protective cover 12 has a laminated structure in which a functional layer 12a and a functional layer 12b are laminated. The functional layer 12b located on the display surface side (opposite side to the display panel 11) is a layer containing the above-described self-healing organic resin. Further, as the functional layer 12a located on the display panel 11 side, a sheet-like member containing the above-described urethane resin or the like can be used.

[0064] Further, as shown in FIG. 2E, a protective cover 14 may be provided on the back side of the display panel 11 (the side of the support 21 or the support 22). Since the curved portions of the display panel 11 are not supported by the support 21 and the support 22, by providing the protective cover 14 on the back side of the display panel 11, a display device 10 with higher mechanical strength can be obtained. The protective cover 14 may be made of the same material as the protective cover 12.

[0065] Also at this time, as shown in FIG. 2F, the protective cover 14 may have a laminated structure in which a functional layer 14a and a functional layer 14b are laminated. The functional layer 14a and the functional layer 14b can each be made of the same material as the functional layer 12a and the functional layer 12b.

[0066] Subsequently, the preferred shape and the like when the display panel 11 and the protective cover 12 are curved will be described in detail.

[0067] FIGS. 3A to 3F show schematic cross-sectional views along the bending direction of the display device 10. In each figure, the rotation axes 31a of the support 21 and the rotation axis 32a of the support 22 are each indicated by a circle.

[0068] Also, the angles shown in each figure indicate the angle formed by a pair of flat surfaces sandwiching the curved portion of the display panel 11. Note that this angle can also be described as the angle formed by a pair of surfaces of the support 21 and the support 22 that support the display panel 11, or the angle obtained by subtracting the sum of the absolute values of the rotation angles of the support 21 and the support 22 (the rotation angle from the state of FIG. 3A) from 180 degrees. Hereinafter, the angle formed by a pair of flat surfaces sandwiching the curved portion of the display panel 11 may be simply referred to as the "angle" for explanation.

[0069] Here, for simplicity, the case where the lengths of the display panel 11 and the protective cover 12 in the cross-sectional direction are the same is shown. Also, as shown in FIG. 3A, the case where the ends of the display panel 11 and the protective cover 12 coincide when the display panel 11 is not curved is shown.

[0070] In FIGS. 3A to 3F, an example is shown in which the end portions of the protective cover 12 and the support 21 are fixed. That is, the protective cover 12 is deformed so as to slide (shift) toward the support 22 side.

[0071] FIGS. 3B, 3C, 3D, 3E, and 3F each show a case where the angle is 150 degrees, 120 degrees, 90 degrees, 30 degrees, and 0 degrees, respectively. Also, in each figure, the amount of shift of the protective cover 12 from the state where the angle is 180 degrees (i.e., the state where it is not curved) is clearly shown. Here, the amount of shift when the angle is α degrees is denoted as D α and, for example, D 150 represents the amount of shift when the angle is 150 degrees.

[0072] It is preferable that the amount of shift of the protective cover 12 gradually increases as the angle decreases, at least in the range of 90 degrees or more and 180 degrees or less. Although it is shown that the amount of shift also gradually increases at angles less than 90 degrees, the amount of shift may not change or may decrease in this angle range.

[0073] Here, when the display panel 11 functions as a touch panel, it is preferably used in the angle range of 90 degrees or more and less than 180 degrees when operating the display panel 11 in a curved state. When the display panel 11 is curved at an angle smaller than this (i.e., less than 90 degrees), touch operations and pen input operations become difficult. Therefore, at least in the angle range of 90 degrees or more and less than 180 degrees, it is preferable that the protective cover 12 is deformed so that the amount of shift of the protective cover 12 increases and the gap between the display panel 11 and the protective cover 12 increases as the angle decreases.

[0074] Further, in a state where the display panel 11 is flat (i.e., in a state of an angle of 180 degrees), or in a state where at least the display panel 11 is curved at a predetermined angle within an angle range of 90 degrees or more and less than 180 degrees, it is preferable that the end portion of the protective cover 12 is in a state where tension is applied in the bending direction (i.e., in a state where a pulling force is applied outward). With such a configuration, it is possible to prevent the surface of the protective cover 12 from sagging, suppress surface scattering of external light, and obtain a display device with high visibility. Further, since the protective cover 12 is held in a pulled state, even when repeatedly deformed between the bent state and the flat state, it always has the same shape at the same angle, so that a highly reliable display device can be obtained.

[0075] The mechanism for applying tension to the protective cover 12 may be a mechanism for pulling either one of a pair of end portions perpendicular to the bending direction of the protective cover 12. Alternatively, it may be a mechanism for pulling both of them. Such a mechanism may be provided in either one or both of the support 21 and the support 22, or may be incorporated into a housing of an electronic device or the like separately from the support.

[0076] FIGS. 4A to 4D show schematic cross-sectional views of the curved portion of the display panel 11 enlarged. FIGS. 4A, 4B, 4C, and 4D show states of angles of 120 degrees, 90 degrees, 30 degrees, and 0 degrees, respectively.

[0077] Here, a case where the display panel 11 and the protective cover 12 are each curved in an ideal arc shape will be described. Note that depending on the configuration of the display device, it may not be in an ideal arc shape. Even in such a case, the side surface or cross-section of each curved portion may be approximated by an ideal arc.

[0078] In FIGS. 4A to 4D, the center O 1 and the radius of curvature r 1 of the arc formed by the curved surface on the display surface side of the display panel 11, and the center O 2 and the radius of curvature r 2 of the arc formed by the curved surface on the upper surface side (opposite side to the display panel 11) of the protective cover 12 are shown.

[0079] Represents the radius of curvature r of the display panel 11 1 and the radius of curvature r of the protective cover 12 2 In the angular range of at least less than 180 degrees and more than 90 degrees, r 1 < r 2 It is preferable to satisfy. That is, in at least the above-described angular range, it is preferable that the protective cover 12 is curved with a radius of curvature larger than that of the display panel 11. Thereby, as shown in FIGS. 4A and 4B, a gap having a crescent cross-sectional shape can be preferably formed between the display panel 11 and the protective cover 12 at the curved portion. Further, the portion where no gap is provided (for example, the portion where the display panel 11 and the protective cover 12 are in contact) can always be the portion where the display panel 11 is supported by the support 21 or the support 22.

[0080] Also, at a predetermined angle smaller than 90 degrees, the radius of curvature r 1 and the radius of curvature r 2 The magnitude relationship is reversed, and for example, as shown in FIGS. 4C and 4D, the radius of curvature r 2 is smaller than the radius of curvature r 1

[0081] Also, when focusing on the center O 1 and the center O 2 When looking at, the center O 1 is preferably always located inside (on the display panel 11 side) of the center O 2 . Thereby, when the display panel 11 is curved, it is possible to form a configuration in which a gap always occurs between the display panel 11 and the protective cover 12.

[0082] In addition, for example, when the display panel 11 and the protective cover 12 are adhered and integrated, the center O 1 and the center O 2 are approximately coincident.

[0083] ​For example, when the display panel 11 and the protective cover 12 are adhered to form an integral unit, the total thickness increases. As a result, when the display panel 11 is bent, the stress generated becomes large, and in the worst case, the display panel 11 may break. However, in the display device 10, since the display panel 11 and the protective cover 12 are configured to bend independently with different radii of curvature, the stress generated when the display panel 11 is bent can be reduced, preventing damage.

[0084] [Modification Example] Hereinafter, a modification example of the above-described configuration example will be described.

[0085] [Modification Example 1] In the configuration illustrated in FIG. 3A and the like above, the case where the ends of the protective cover 12 and the support 21 are fixed is shown. However, the protective cover 12 may be configured not to be fixed to any of the supports.

[0086] FIGS. 5A to 5F show a configuration in which the protective cover 12 can be displaced on both the support 21 side and the support 22 side.

[0087] Here, the amount of displacement of the protective cover 12 toward the support 21 is denoted as (L), and the amount of displacement toward the support 22 is denoted as (R). For example, D 150 (L), D 150 (R) respectively indicate the amount of displacement of the protective cover 12 toward the support 21 and the amount of displacement toward the support 22 when the angle is 150 degrees. Here, when the shape of the curved portion of the protective cover 12 is the same as the configuration shown in FIG. 3B and the like, for example, D 150 (L) and D 150 (R) added together is approximately equal to D 150 in FIG. 3B.

[0088] In this way, when the protective cover 12 is bent, by configuring the pair of ends to be displaced respectively, compared with the configuration shown in FIG. 3A and the like, the amount of displacement of the protective cover 12 with respect to the support 22 can be reduced, so that the electronic device including the display device can be miniaturized.

[0089] Incidentally, the amount of displacement of the protective cover 12 toward the support 21 and the amount of displacement toward the support 22 may be the same or may be different displacement amounts. Making the respective displacement amounts approximately the same is preferable because the amount of displacement of the protective cover 12 with respect to the support 21 and the amount of displacement with respect to the support 22 can be minimized.

[0090] [Modification Example 2] In the above-described configuration example and Modification Example 1, an example in which the display panel 11 and the protective cover 12 are provided in contact with each other at a non-curved portion of the display panel 11 has been shown, but a configuration in which a gap is provided between them may also be used.

[0091] In FIGS. 6A to 6F, examples in which a gap with an interval G is provided between the display panel 11 and the protective cover 12 and they are not in contact with each other are shown.

[0092] In this way, by configuring the non-curved portion of the display panel 11 such that the protective cover 12 does not come into contact with it, higher mechanical strength can be achieved.

[0093] Further, as shown in FIG. 6A, when the display panel 11 and the protective cover 12 are not curved, it is preferable that the protective cover 12 is supported by the support 21, the support 22, or the housing of the electronic device or the like such that the distance (interval G) between the display panel 11 and the protective cover 12 is uniform at least within the display portion 15. For example, if a part of the protective cover 12 sags or the like and the distance between the display panel 11 and the protective cover 12 varies, the surface reflection of the protective cover 12 becomes non-uniform, and the visibility may decrease. Therefore, by making the distance between the display panel 11 and the protective cover 12 uniform, a display device with high display quality can be realized.

[0094] For example, outside the display portion 15, a mechanism such as a slit structure for slidably holding the protective cover 12 may be provided on the support 21, the support 22, or the like.

[0095] Further, a structure in which air exists (also referred to as a structure provided with an air gap) can be formed between the display panel 11 and the protection cover 12. Further, a fluid such as a gas, a liquid, a gel, or a sheet-like member having fluidity may be provided between the display panel 11 and the protection cover 12. At this time, a material having a refractive index higher than that of air can be used for the fluid. In particular, it is preferable that the refractive index is close to that of the member located on the outermost surface of the display panel 11 or the member constituting the protection cover 12 (for example, the difference in refractive index is 10% or less, preferably 5% or less), because the light extraction efficiency can be increased.

[0096] 〔Modification Example 3〕 One or more sheet-like members may be provided between the display panel 11 and the protection cover 12.

[0097] FIGS. 7A to 7D show an example in which a functional layer 13 is provided between the display panel 11 and the protection cover 12. The functional layer 13 preferably has flexibility, similar to the display panel 11, the protection cover 12, and the like.

[0098] The functional layer 13 may have a function as a touch sensor panel or a function as an optical film. As the touch sensor panel, a configuration including sensor elements such as a capacitance-type touch sensor, an optical sensor, and a pressure-sensitive touch sensor can be adopted. Examples of the optical film include a circular polarizing plate, an antireflection film (including an AR film and an AG film), and the like.

[0099] As shown in FIGS. 7B to 7D, when the display panel 11 is curved, it is preferable that a part of the functional layer 13 is deformed so as to be relatively displaced with respect to the display panel 11 so that a gap is provided between the curved portion of the display panel 11 and the functional layer 13. At this time, it is also preferable that each is deformed so that a gap is provided between the functional layer 13 and the protection cover 12.

[0100] Also, as shown in FIGS. 7B and 7C, when the display panel 11 is curved within a range of 90 degrees or more and less than 180 degrees, the functional layer 13 preferably curves such that the radius of curvature is larger than that of the display panel 11 and smaller than that of the protective cover 12. Further, as shown in FIG. 7D, when the display panel 11 is folded (at an angle of 0 degrees), the functional layer 13 preferably curves such that the radius of curvature of the functional layer 13 is smaller than that of the display panel 11 and larger than that of the protective cover 12.

[0101] In addition, in FIG. 7A and the like, an example is shown in which the display panel 11, the functional layer 13, and the functional layer 13 and the protective cover 12 are in contact with each other when the display panel 11 is not curved. However, similar to the above-described Modification 2, a configuration in which these do not contact each other may also be used.

[0102] Also, in FIG. 7A and the like, an example is shown in which the functional layer 13 and the protective cover 12 are displaced only to the support 22 side. However, similar to the above-described Modification 1, a configuration in which they are displaced to both the support 21 side and the support 22 side may also be used.

[0103] Further, when the functional layer 13 is sufficiently thin compared to the display panel 11 or sufficiently flexible compared to the display panel 11, the functional layer 13 may be adhered and fixed to the display panel 11 or the protective cover 12. In particular, when the display panel 11 and the functional layer 13 are adhered, it is preferable that the neutral plane of the laminate in which the display panel 11 and the functional layer 13 are laminated is located inside the display panel 11.

[0104] [Examples of the configuration of the support] Subsequently, an example of the configuration of the support 21 and the support 22 will be described.

[0105] Figures 8A to 8C respectively show schematic perspective views of the support 21 and the support 22. In each figure, the display panel 11 is shown by a dashed line. Figure 8A shows the state where the display panel 11 is not curved. Figure 8B shows the state where the angle formed by two flat surfaces of the display panel 11 is curved to 120 degrees. Figure 8C shows the state where two flat surfaces of the display panel 11 are parallel (that is, the angle formed by them is 0 degrees).

[0106] A pair of gears 31 are attached to both ends of the support 21, and a pair of gears 32 are attached to both ends of the support 22. The gears 31 and 32 are respectively fixed to the support 21 or the support 22. The gear 31 and the gear 32 mesh with a gear ratio of 1:1, and they are configured to be rotatable at the same angle in opposite directions. Therefore, the support 21 and the support 22 can rotate at the same angle in opposite directions respectively. Therefore, the support 21 and the support 22 can be reversibly deformed from the form shown in Figure 8A, through the form shown in Figure 8B, to the form shown in Figure 8C.

[0107] Also, with such a configuration, the support 21 and the support 22 can rotate around their respective rotation axes while the relative positions of their rotation axes do not change. With such a configuration, even if the display panel 11 is fixed to both the support 21 and the support 22, the display panel 11 can be curved without expanding or contracting in the bending direction.

[0108] Figures 8A to 8C also show the region 28 where the display panel 11 is always supported by the support 21 or the support 22. That is, the region 28 is the region where the display panel 11 is always fixed along the surface of the support 21 or the support 22. Also, in the region between the pair of regions 28, the display panel 11 and the support 21 or the support 22 are not fixed, and the display panel 11 can float from the surface of the support 21 or the support 22.

[0109] For example, the display panel 11, the support 21, and the support 22 can be configured to be adhered and fixed via an adhesive material, an adhesive sheet, or the like in the region 28. Alternatively, the entire region including the curved portion of the display panel 11 may be configured to be attached to the support 21 and the support 22 with a weakly adhesive adhesive sheet that can be easily peeled off. At this time, since the non-curved portion of the display panel 11 does not lift (peel off) from the support 21 or the support 22 even when the support 21 and the support 22 are rotated, it is substantially fixed to the support 21 or the support 22.

[0110] FIG. 9A is a schematic side view of the curved portion when the display panel 11 is bent at 90 degrees, as viewed from a direction perpendicular to the bending direction. In FIG. 9A, the gears 31 and 32 are shown by dashed lines.

[0111] FIG. 9A shows an example in which holding members 23 are provided on the supports 21 and 22, respectively. The display panel 11 and the protection cover 12 have regions sandwiched between the support 21 and the holding member 23 and regions sandwiched between the support 22 and the holding member 23. The holding member 23 functions as a guide for slidably holding the display panel 11 or the protection cover 12.

[0112] The pair of holding members 23 can be provided in a region outside the display portion of the display panel 11. As the pair of holding members 23, a member having a U-shaped or square bracket-like upper surface shape surrounding the display portion of the display panel 11 can be used. The holding member 23 and the support 21 or the support 22 may be fixed to each other with screws, an adhesive material, or the like, or they may be integrally formed. Since the holding member 23 is fixed to the support 21 or the support 22, it can also be interpreted as a part of the support 21 or the support 22.

[0113] The protection cover 12 is slidably held between the display panel 11 and the holding member 23.

[0114] FIG. 9B shows an example in which a spacer 24 is provided between the display panel 11 and the protective cover 12. The spacer 24 holds the display panel 11 and the protective cover 12 in a separated state by the thickness of the spacer 24.

[0115] The protective cover 12 is slidably held between the spacer 24 and the holding member 23. Therefore, it can be said that the holding member 23 and the spacer 24 form a slit structure for holding the protective cover 12.

[0116] The spacer 24 may have a U-shaped upper surface shape similar to that of the holding member 23. Alternatively, the spacer 24 may be provided along both ends of the holding member 23. Further, the spacer 24 is preferably fixed to the support 21 or the support 22. The spacer 24 can also be interpreted as a part of the support 21 or the support 22.

[0117] FIGS. 9C and 9D show examples in which the shape of the end portion of the holding member 23 is different from the above.

[0118] In FIGS. 9C and 9D, the end portion of the holding member 23 is processed to have a convex curved surface. For example, it is preferable that the end portion of the holding member 23 is processed to have a cross-sectional shape on an arc.

[0119] Further, the protective cover 12 is deformed so as to curve along the curved surface at the end portions of the pair of holding members 23. By processing the end portion of the holding member 23 to have a convex curved surface, it is possible to prevent the protective cover 12 from bending with a radius smaller than the radius of curvature of the curved surface. That is, the holding member 23 has a function of controlling the curvature of the protective cover 12.

[0120] Also, when such a holding member 23 is provided, the curved portion of the protective cover 12 can be composed of a pair of curved portions having a smaller radius of curvature than the display panel 11 and a substantially flat portion therebetween. Even with such a configuration, the distance between the curved portion of the display panel 11 and the protective cover 12 can vary according to the angle at which the display panel 11 is bent.

[0121] Subsequently, an example of a tension mechanism for applying tension to the end of the protective cover 12 will be described. By applying tension from the end side along the bending direction of the protective cover 12, it is possible to suppress the occurrence of wrinkles and sags in the protective cover 12. Also, even when the bending and stretching operations are repeated, displacement between the protective cover 12 and the display panel 11 can be prevented.

[0122] FIG. 10B1 shows a schematic cross-sectional view near the end of the support 22. The display panel 11 and the protective cover 12 are provided between the support 22 and the holding member 23. The protective cover 12 is slidably held with respect to the display panel 11.

[0123] Furthermore, a spring 41a and a movable member 42 are provided near the end of the support 22. Also, the support 22 is provided with a recess in which the movable member 42 can move, and the movable range of the movable member 42 is controlled by the shape of the recess.

[0124] The movable member 42 is fixed to the protective cover 12 by an adhesive member 43. In FIG. 10B1, an example is shown in which the movable member 42 is fixed to the upper surface of the protective cover 12, but it is not limited thereto, and it may be fixed to the back surface of the protective cover. Also, the fixing method between the movable member 42 and the protective cover 12 is not limited to this, and for example, the protective cover 12 may be fixed by fitting it into the movable member 42 without using the adhesive member 43.

[0125] FIG. 10A shows the spring 41a when its length is the natural length L 0 as shown in FIG. 10B1, the spring 41a is disposed between the support 22 and the movable member 42 with a natural length L 0It is arranged in a contracted state. As a result, as indicated by the dashed arrow in FIG. 10B1, a tension force in the outward direction is always applied to the protective cover 12 via the movable member 42.

[0126] FIG. 10B1 shows the state when the display panel 11 is curved at an angle θ 0 (θ = θ 0 ), and FIG. 10B2 shows the state when it is curved to a smaller angle (θ < θ 0 ). Here, θ 0 includes 180 degrees, that is, the state where the display panel 11 is not curved.

[0127] FIGS. 10C1 and 10C2 show an example when the spacer 24 is provided. Also, FIGS. 10C1 and 10C2 show an example where the back surface of the protective cover 12 and the movable member 42 are fixed by the adhesive member 43. Further, as shown in FIGS. 10C1 and 10C2, the holding member 23 may be provided to cover the end portion of the protective cover 12, the spring 41a, the adhesive member 43, and the movable member 42.

[0128] In the above, an example of using the spring 41a in a contracted state was shown. On the contrary, it may be used in a stretched state.

[0129] FIG. 10D shows a spring 41b having a natural length L 0 . As shown in FIGS. 10E1 and 10E2, the spring 41b is in a state of being stretched from the natural length L 0 , and both ends thereof are fixed to the movable member 42 and the support 22, respectively.

[0130] Also, FIGS. 10F1 and 10F2 show an example when the spacer 24 is provided.

[0131] The tension mechanism exemplified here is preferably selected such that when the display panel is curved from 180 degrees to 0 degrees, a tension is applied to the end portion of the protective cover 12 in at least the range of 90 degrees or more and 180 degrees or less, by selecting the movable range of the movable member 42, the spring constant of the spring, etc.

[0132] [Specific examples of display devices] Hereinafter, a more specific configuration example of a display device will be described. FIG. 11 shows a perspective schematic view of a display device 10. Further, FIG. 12A shows a perspective schematic view of the display device 10 shown in FIG. 11 disassembled by parts.

[0133] As shown in FIGS. 11 and 12A, the display device 10 includes a support 21, a support 22, a holding member 23a, a holding member 23b, a spacer 24a, a spacer 24b, a gear 31, a gear 32, a protective cover 12, and a display panel 11.

[0134] A part of the display panel 11 is sandwiched between the support 21 and the spacer 24a, and another part is sandwiched between the support 22 and the spacer 24b. The display panel 11 and the supports 21 and 22 are bonded together with a weakly adhesive adhesive sheet, respectively.

[0135] A part of the protective cover 12 is sandwiched between the spacer 24a and the holding member 23a, and another part is sandwiched between the spacer 24b and the holding member 23a. The protective cover 12 is slidably held between the spacer 24a and the holding member 23a and between the spacer 24b and the holding member 23a.

[0136] Further, the gear 31 is attached to the support 21, and the gear 32 is attached to the support 22, respectively. Also, the gear 31 and the gear 32 are covered with a cover 33.

[0137] Further, FIG. 12B shows an enlarged view of the end of the spacer 24b. The spacer 24b is provided with a recess for arranging a spring 41. Also, a movable member 42 is provided on the spacer 24b. The spring 41 is arranged in the recess in a state of being contracted from its natural length. One side of the recess on the movable member 42 side is cut away, and one end of the spring 41 is provided to contact the movable member 42. The protective cover 12 can be attached to the upper surface of the movable member 42 using an adhesive or the like.

[0138] The spacer 24a, the spacer 24b, the holding member 23a, and the holding member 23b each have a U-shaped upper surface shape so as to overlap with the non-display area of the display panel 11 and not overlap with the display unit. The user can view the image displayed on the display unit 15 of the display panel 11 through the protective cover 12 in the area surrounded by the pair of holding members 23a and 23b.

[0139] The above is the description of the specific example of the display device 10.

[0140] The configuration examples illustrated in the present embodiment, and the corresponding drawings and the like can be implemented by appropriately combining at least a part of them with other configuration examples, drawings, and the like.

[0141] The present embodiment can be implemented by appropriately combining at least a part of it with other embodiments described in this specification.

[0142] (Embodiment 2) In the present embodiment, a configuration example of a display panel applicable to a display device according to an aspect of the present invention will be described.

[0143] [Configuration example] FIG. 13 shows a top view of a display panel 700. The display panel 700 is applied with a flexible support substrate 745 and can be used as a flexible display. The display panel 700 also has a pixel portion 702 provided on the flexible support substrate 745. Further, a source driver circuit portion 704, a pair of gate driver circuit portions 706, wirings 710, and the like are provided on the support substrate 745. A plurality of display elements are provided in the pixel portion 702.

[0144] In addition, an FPC terminal portion 708 to which an FPC 716 (FPC: Flexible printed circuit) is connected is provided in a part of the support substrate 745. Various signals and the like are supplied to each of the pixel portion 702, the source driver circuit portion 704, and the gate driver circuit portion 706 through the FPC terminal portion 708 and the wiring 710 by the FPC 716.

[0145] A pair of gate driver circuit units 706 are provided on both sides with the pixel unit 702 interposed therebetween. Note that the gate driver circuit unit 706 and the source driver circuit unit 704 may be separately formed on a semiconductor substrate or the like and may be in the form of packaged IC chips. The IC chips can be mounted on a support substrate 745 by COF (Chip On Film) technology or the like.

[0146] It is preferable to apply transistors having an oxide semiconductor to the transistors included in the pixel unit 702, the source driver circuit unit 704, and the gate driver circuit unit 706.

[0147] As the display element provided in the pixel unit 702, a light-emitting element or the like can be used. Examples of the light-emitting element include self-luminous light-emitting elements such as an LED (Light Emitting Diode), an OLED (Organic LED), a QLED (Quantum-dot LED), and a semiconductor laser. Further, as the display element, a liquid crystal element such as a transmissive liquid crystal element, a reflective liquid crystal element, or a transflective liquid crystal element can also be used. Further, an MEMS (Micro Electro Mechanical Systems) element of a shutter method or an optical interference method, a display element to which a microcapsule method, an electrophoresis method, an electro-wetting method, or an electronic ink (registered trademark) method or the like is applied can also be used.

[0148] Further, FIG. 13 shows an example in which a portion of the support substrate 745 where the FPC terminal portion 708 is provided has a protruding shape. A part of the support substrate 745 including the FPC terminal portion 708 can be folded back to the back side in the region P1 in FIG. 13. By folding back a part of the support substrate 745, the display panel 700 can be mounted on an electronic device or the like with the FPC 716 disposed to overlap the back side of the pixel unit 702, and the space saving and miniaturization of the electronic device or the like can be achieved.

[0149] Further, an IC 717 is mounted on an FPC 716 connected to the display panel 700. The IC 717 has a function as a source driver circuit, for example. At this time, the source driver circuit section 704 in the display panel 700 can be configured to include at least one of a protection circuit, a buffer circuit, a demultiplexer circuit, and the like.

[0150] [Cross-sectional configuration example] Hereinafter, a configuration using an organic EL element as a display element will be described with reference to FIGS. 14 and 15. FIGS. 14 and 15 are schematic cross-sectional views taken along the dashed-dotted line S-T of the display panel 700 shown in FIG. 13.

[0151] First, the common parts of the display panels shown in FIGS. 14 and 15 will be described.

[0152] FIGS. 14 and 15 show a cross-section including a pixel section 702, a gate driver circuit section 706, and an FPC terminal section 708. The pixel section 702 has a transistor 750 and a capacitor element 790. The gate driver circuit section 706 has a transistor 752.

[0153] The transistor 750 and the transistor 752 are transistors in which an oxide semiconductor is applied to a semiconductor layer in which a channel is formed. Note that the present invention is not limited to this, and transistors using silicon (amorphous silicon, polycrystalline silicon, or single-crystalline silicon) or an organic semiconductor can also be applied to the semiconductor layer.

[0154] The transistor used in the present embodiment has an oxide semiconductor film with high purity and suppression of the formation of oxygen vacancies. The transistor can significantly reduce the off-current. Therefore, a pixel to which such a transistor is applied can increase the holding time of an electrical signal such as an image signal, and can also set a long writing interval for an image signal or the like. Thus, the frequency of the refresh operation can be reduced, and power consumption can be reduced.

[0155] In addition, since the transistor used in this embodiment can obtain a relatively high field-effect mobility, it can be driven at high speed. For example, by using such a transistor capable of high-speed driving in a display panel, the switching transistor in the pixel portion and the driver transistor used in the drive circuit portion can be formed on the same substrate. That is, a configuration that does not apply a drive circuit formed of a silicon wafer or the like is also possible, and the number of components of the display device can be reduced. Also, in the pixel portion, by using a transistor capable of high-speed driving, a high-quality image can be provided.

[0156] The capacitive element 790 includes a lower electrode formed by processing a film identical to the first gate electrode of the transistor 750, and an upper electrode formed by processing a metal oxide film identical to the semiconductor layer. The upper electrode has a reduced resistance, similar to the source region and the drain region of the transistor 750. Also, a part of the insulating film that functions as the first gate insulating layer of the transistor 750 is provided between the lower electrode and the upper electrode. That is, the capacitive element 790 has a stacked structure in which an insulating film that functions as a dielectric film is sandwiched between a pair of electrodes. Further, a wiring obtained by processing a film identical to the source electrode and the drain electrode of the transistor 750 is connected to the upper electrode.

[0157] Also, an insulating layer 770 that functions as a planarization film is provided on the transistor 750, the transistor 752, and the capacitive element 790.

[0158] The transistor 750 included in the pixel portion 702 and the transistor 752 included in the gate driver circuit portion 706 may use transistors having different structures. For example, a configuration in which a top-gate type transistor is applied to one of them and a bottom-gate type transistor is applied to the other may be used. Note that the same applies to the source driver circuit portion 704 as to the gate driver circuit portion 706.

[0159] The FPC terminal portion 708 has a wiring 760, an anisotropic conductive film 780, and an FPC 716, with a part of the wiring 760 functioning as a connection electrode. The wiring 760 is electrically connected to the terminals of the FPC 716 via the anisotropic conductive film 780. Here, the wiring 760 is formed of the same conductive film as the source electrode and drain electrode of the transistor 750 or the like.

[0160] Subsequently, the display panel 700 shown in FIG. 14 will be described.

[0161] The display panel 700 shown in FIG. 14 has a support substrate 745 and a support substrate 740. As the support substrate 745 and the support substrate 740, a flexible substrate such as a glass substrate or a plastic substrate can be used, for example.

[0162] The transistor 750, the transistor 752, the capacitor element 790, etc. are provided on the insulating layer 744. The support substrate 745 and the insulating layer 744 are bonded by an adhesive layer 742.

[0163] The display panel 700 also has a light-emitting element 782, a coloring layer 736, a light-shielding layer 738, etc.

[0164] The light-emitting element 782 has a conductive layer 772, an EL layer 786, and a conductive layer 788. The conductive layer 772 is electrically connected to the source electrode or drain electrode of the transistor 750. The conductive layer 772 is provided on the insulating layer 770 and functions as a pixel electrode. Also, an insulating layer 730 is provided to cover the end portion of the conductive layer 772, and the EL layer 786 and the conductive layer 788 are laminated and provided on the insulating layer 730 and the conductive layer 772.

[0165] For the conductive layer 772, a material having reflectivity to visible light can be used. For example, materials including aluminum, silver, etc. can be used. Also, for the conductive layer 788, a material having translucency to visible light can be used. For example, it is advisable to use an oxide material containing indium, zinc, tin, etc. Therefore, the light-emitting element 782 is a top-emission type light-emitting element that emits light to the side opposite to the formation surface (the support substrate 740 side).

[0166] The EL layer 786 has an organic compound or an inorganic compound such as quantum dots. The EL layer 786 contains a light-emitting material that exhibits white light when an electric current flows.

[0167] As the light-emitting material, a fluorescent material, a phosphorescent material, a thermally activated delayed fluorescence (TADF) material, an inorganic compound (such as a quantum dot material), etc. can be used. Examples of materials that can be used for quantum dots include colloidal quantum dot materials, alloy-type quantum dot materials, core-shell type quantum dot materials, core-type quantum dot materials, etc.

[0168] The light-shielding layer 738 and the coloring layer 736 are provided on one surface of the insulating layer 746. The coloring layer 736 is provided at a position overlapping the light-emitting element 782. Also, the light-shielding layer 738 is provided in a region that does not overlap the light-emitting element 782 in the pixel portion 702. Also, the light-shielding layer 738 may be provided so as to overlap with the gate driver circuit portion 706, etc.

[0169] The support substrate 740 is bonded to the other surface of the insulating layer 746 by an adhesive layer 747. Also, the support substrate 740 and the support substrate 745 are bonded by a sealing layer 732.

[0170] Here, a light-emitting material that exhibits white light emission is applied to the EL layer 786 of the light-emitting element 782. The white light emitted by the light-emitting element 782 is colored by the coloring layer 736 and then emitted to the outside. The EL layer 786 is provided across pixels that exhibit different colors. By arranging in a matrix pixels provided with the coloring layer 736 that transmits any one of red light (R), green light (G), or blue light (B) in the pixel portion 702, the display panel 700 can perform full-color display.

[0171] Further, as the conductive layer 788, a conductive film having transparency and reflectivity may be used. At this time, a microcavity structure can be realized between the conductive layer 772 and the conductive layer 788, and the light of a specific wavelength can be enhanced and emitted. Also at this time, an optical adjustment layer for adjusting the optical distance is disposed between the conductive layer 772 and the conductive layer 788, and by making the thickness of the optical adjustment layer different between pixels of different colors, the color purity of the light emitted from each pixel can be increased.

[0172] Note that when the EL layer 786 is formed in an island shape for each pixel or in a stripe shape for each pixel row, that is, by painting, the coloring layer 736 and the above-described optical adjustment layer may not be provided.

[0173] Here, it is preferable to use an inorganic insulating film that functions as a barrier film with low moisture permeability for the insulating layer 744 and the insulating layer 746, respectively. By adopting a configuration in which the light-emitting element 782, the transistor 750, etc. are sandwiched between such an insulating layer 744 and the insulating layer 746, the deterioration of these can be suppressed, and a highly reliable display panel can be realized.

[0174] In the display panel 700A shown in FIG. 15, a resin layer 743 is provided between the adhesive layer 742 and the insulating layer 744 shown in FIG. 14. Further, instead of the support substrate 740, it has a protective layer 749.

[0175] The resin layer 743 is a layer containing an organic resin such as polyimide or acrylic. The insulating layer 744 includes an inorganic insulating film such as silicon oxide, silicon oxynitride, or silicon nitride. The resin layer 743 and the support substrate 745 are bonded together by an adhesive layer 742. The resin layer 743 is preferably thinner than the support substrate 745.

[0176] The protective layer 749 is bonded to the sealing layer 732. As the protective layer 749, a glass substrate, a resin film, or the like can be used. Further, as the protective layer 749, an optical member such as a polarizing plate (including a circular polarizing plate), a diffusing plate, an input device such as a touch sensor panel, or a configuration in which two or more of these are laminated may be applied.

[0177] Also, the EL layer 786 of the light-emitting element 782 is provided in an island shape on the insulating layer 730 and the conductive layer 772. By making the EL layer 786 emit different light colors for each sub-pixel, color display can be realized without using the coloring layer 736.

[0178] Also, a protective layer 741 is provided to cover the light-emitting element 782. The protective layer 741 has a function of preventing impurities such as water from diffusing into the light-emitting element 782. The protective layer 741 has a laminated structure in which an insulating layer 741a, an insulating layer 741b, and an insulating layer 741c are laminated in this order from the conductive layer 788 side. At this time, it is preferable to use an inorganic insulating film with a high barrier property against impurities such as water for the insulating layer 741a and the insulating layer 741c, and an organic insulating film that functions as a planarizing film for the insulating layer 741b. Further, the protective layer 741 is preferably also extended and provided to the gate driver circuit portion 706.

[0179] Also, inside the sealing layer 732, it is preferable that an organic insulating film covering transistors 750, 752, etc. is formed in an island shape. In other words, it is preferable that the end portion of the organic insulating film is located inside the sealing layer 732 or in a region overlapping with the end portion of the sealing layer 732. FIG. 15 shows an example in which the insulating layer 770, the insulating layer 730, and the insulating layer 741b are processed into an island shape. For example, in the portion overlapping with the sealing layer 732, the insulating layer 741c and the insulating layer 741a are provided in contact with each other. In this way, by adopting a configuration in which the surface of the organic insulating film covering the transistors 750 and 752 is not exposed outside the sealing layer 732, it is possible to suitably prevent water and hydrogen from diffusing from the outside to the transistors 750 and 752 through the organic insulating film. As a result, fluctuations in the electrical characteristics of the transistors can be suppressed, and a highly reliable display device can be realized.

[0180] Also, in FIG. 15, in the foldable region P1, in addition to the support substrate 745 and the adhesive layer 742, there is a portion where an inorganic insulating film such as the insulating layer 744 is not provided. Also, in the region P1, in order to prevent the wiring 760 from being exposed, the insulating layer 770 containing an organic material has a configuration that covers the wiring 760. By adopting a configuration in which the foldable region P1 is provided with as few inorganic insulating films as possible and only a conductive layer containing a metal or an alloy and a layer containing an organic material are laminated, it is possible to prevent cracks from occurring when bent. Also, by not providing the support substrate 745 in the region P1, a part of the display panel 700A can be bent with an extremely small radius of curvature.

[0181] Also, in FIG. 15, a conductive layer 761 is provided on the protective layer 741. The conductive layer 761 can be used as a wiring or an electrode.

[0182] Also, when a touch sensor is provided over the display panel 700A, the conductive layer 761 can function as an electrostatic shielding film to prevent electrical noise generated when driving pixels from being transmitted to the touch sensor. At this time, a configuration may be adopted in which a predetermined constant potential is applied to the conductive layer 761.

[0183] Alternatively, the conductive layer 761 can be used, for example, as an electrode of a touch sensor. Thereby, the display panel 700A can function as a touch panel. For example, the conductive layer 761 can be used as an electrode or wiring of a capacitance-type touch sensor. At this time, the conductive layer 761 can be used as wiring or an electrode to which a detection circuit is connected, or wiring or an electrode to which a sensor signal is input. In this way, by forming a touch sensor on the light-emitting element 782, the number of components can be reduced, and the manufacturing cost of an electronic device or the like can be reduced.

[0184] The conductive layer 761 is preferably provided in a portion that does not overlap with the light-emitting element 782. For example, the conductive layer 761 can be provided at a position overlapping with the insulating layer 730. Thereby, it is not necessary to use a transparent conductive film having relatively low conductivity as the conductive layer 761, and a metal or alloy having high conductivity can be used, so that the sensitivity of the sensor can be increased.

[0185] Note that the method of the touch sensor that can be configured using the conductive layer 761 is not limited to the capacitance method, and various methods such as a resistive film method, a surface acoustic wave method, an infrared method, an optical method, and a pressure-sensitive method can be used. Alternatively, two or more of these may be used in combination.

[0186] [Regarding Components] Hereinafter, components such as transistors applicable to the display device will be described.

[0187] [Transistor] The transistor has a conductive layer that functions as a gate electrode, a semiconductor layer, a conductive layer that functions as a source electrode, a conductive layer that functions as a drain electrode, and an insulating layer that functions as a gate insulating layer.

[0188] Note that the structure of the transistor included in the display device according to one aspect of the present invention is not particularly limited. For example, it may be a planar transistor, a staggered transistor, or an inverted staggered transistor. Further, it may be any of a top gate type or a bottom gate type transistor structure. Alternatively, gate electrodes may be provided above and below the channel.

[0189] The crystallinity of the semiconductor material used for the transistor is also not particularly limited, and any of an amorphous semiconductor, a single crystal semiconductor, or a semiconductor having crystallinity other than a single crystal (microcrystalline semiconductor, polycrystalline semiconductor, or a semiconductor having a crystal region in part) may be used. Using a single crystal semiconductor or a semiconductor having crystallinity is preferable because deterioration of transistor characteristics can be suppressed.

[0190] Hereinafter, a transistor in which a metal oxide film is particularly used for a semiconductor layer in which a channel is formed will be described.

[0191] As the semiconductor material used for the transistor, a metal oxide having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used. Typically, it is a metal oxide containing indium, and for example, CAC-OS described later can be used.

[0192] A transistor using a metal oxide having a wider band gap and a lower carrier density than silicon can hold the charge accumulated in a capacitive element connected in series with the transistor for a long period due to its low off-current.

[0193] The semiconductor layer can be, for example, a film represented by an In-M-Zn-based oxide containing indium, zinc, and M (M is a metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium).

[0194] When the metal oxide constituting the semiconductor layer is an In-M-Zn-based oxide, the atomic ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide preferably satisfies In≥M and Zn≥M. As the atomic ratio of the metal elements of such a sputtering target, In:M:Zn = 1:1:1, In:M:Zn = 1:1:1.2, In:M:Zn = 3:1:2, In:M:Zn = 4:2:3, In:M:Zn = 4:2:4.1, In:M:Zn = 5:1:6, In:M:Zn = 5:1:7, In:M:Zn = 5:1:8, etc. are preferable. Note that the atomic ratio of the semiconductor layer formed includes a variation of plus or minus 40% of the atomic ratio of the metal elements contained in the above sputtering target.

[0195] As the semiconductor layer, a metal oxide film with a low carrier density is used. For example, the carrier density of the semiconductor layer is 1×10 17 / cm 3 or less, preferably 1×10 15 / cm 3 or less, more preferably 1×10 13 / cm 3 or less, even more preferably 1×10 11 / cm 3 or less, still more preferably 1×10 10 / cm 3 less, and a metal oxide with a carrier density of 1×10 -9 / cm 3 or more can be used. Such a metal oxide is called a high-purity intrinsic or substantially high-purity intrinsic metal oxide. Since the metal oxide has a low impurity concentration and a low defect level density, it can be said that it is a metal oxide having stable characteristics.

[0196] Note that it is not limited to these, and an oxide semiconductor with an appropriate composition may be used according to the required semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, etc.) of the transistor. Further, in order to obtain the required semiconductor characteristics of the transistor, it is preferable to make the carrier density, impurity concentration, defect density, atomic ratio of metal elements and oxygen, interatomic distance, density, etc. of the semiconductor layer appropriate.

[0197] In a metal oxide constituting a semiconductor layer, if silicon or carbon, which is one of the Group 14 elements, is contained, oxygen deficiency increases in the semiconductor layer, resulting in n-type conversion. Therefore, the concentration of silicon or carbon in the semiconductor layer (concentration obtained by secondary ion mass spectrometry) is set to 2×10 18 atoms / cm 3 or less, preferably 2×10 17 atoms / cm 3 or less.

[0198] In addition, when an alkali metal or an alkaline earth metal combines with a metal oxide, carriers may be generated, which may increase the off-current of the transistor. Therefore, the concentration of the alkali metal or alkaline earth metal obtained by secondary ion mass spectrometry in the semiconductor layer is set to 1×10 18 atoms / cm 3 or less, preferably 2×10 16 atoms / cm 3 or less.

[0199] In addition, if nitrogen is contained in the metal oxide constituting the semiconductor layer, electrons, which are carriers, are generated, the carrier density increases, and n-type conversion is likely to occur. As a result, a transistor using a metal oxide containing nitrogen is likely to have normally-on characteristics. Therefore, the nitrogen concentration obtained by secondary ion mass spectrometry in the semiconductor layer is preferably set to 5×10 18 atoms / cm 3 or less.

[0200] Oxide semiconductors can be divided into single-crystalline oxide semiconductors and non-single-crystalline oxide semiconductors. Examples of non-single-crystalline oxide semiconductors include CAAC-OS (c-axis-aligned crystalline oxide semiconductor), polycrystalline oxide semiconductors, nc-OS (nanocrystalline oxide semiconductor), pseudo-amorphous oxide semiconductors (a-like OS: amorphous-like oxide semiconductor), and amorphous oxide semiconductors.

[0201] Note that, as the semiconductor layer of the transistor disclosed in one aspect of the present invention, the above-described non-single crystal oxide semiconductor or CAC-OS can be preferably used. Further, as the non-single crystal oxide semiconductor, nc-OS or CAAC-OS can be preferably used.

[0202] Note that the semiconductor layer may be a mixed film having two or more of a region of CAAC-OS, a region of polycrystalline oxide semiconductor, a region of nc-OS, a region of pseudo-amorphous oxide semiconductor, and a region of amorphous oxide semiconductor. The mixed film may have, for example, a single-layer structure or a laminated structure including any two or more of the above-described regions.

[0203] Further, it is preferable to use CAC-OS (Cloud-Aligned Composite oxide semiconductor) for the semiconductor layer of the transistor disclosed in one aspect of the present invention. By using CAC-OS, high electrical characteristics or high reliability can be imparted to the transistor.

[0204] <Configuration of CAC-OS> Hereinafter, the configuration of CAC (Cloud-Aligned Composite)-OS that can be used for the transistor disclosed in one aspect of the present invention will be described.

[0205] CAC-OS is, for example, a configuration of a material in which elements constituting a metal oxide are unevenly distributed in a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less, or in the vicinity thereof. Hereinafter, in the metal oxide, a state in which one or more metal elements are unevenly distributed and regions having the metal elements are mixed in a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less, or in the vicinity thereof is also referred to as a mosaic state or a patch state.

[0206] The metal oxide preferably contains at least indium, and particularly preferably contains indium and zinc. In addition to these, one or more selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium may also be included.

[0207] For example, in the In-Ga-Zn oxide, CAC-OS (among CAC-OS, the In-Ga-Zn oxide may be particularly referred to as CAC-IGZO.) refers to indium oxide (hereinafter, InO X1 (where X1 is a real number greater than 0).), or indium zinc oxide (hereinafter, In X2 Zn Y2 O Z2 (where X2, Y2, and Z2 are real numbers greater than 0).), and gallium oxide (hereinafter, GaO X3 (where X3 is a real number greater than 0).), or gallium zinc oxide (hereinafter, Ga X4 Zn Y4 O Z4 (where X4, Y4, and Z4 are real numbers greater than 0).) and other materials are separated to form a mosaic shape, and the mosaic-shaped InO X1 , or In X2 Zn Y2 O Z2 is uniformly distributed in the film (hereinafter, also referred to as a cloud-like state).

[0208] That is, CAC-OS is a composite metal oxide having a structure in which a region mainly composed of GaO X3 and a region mainly composed of In X2 Zn Y2 O Z2 , or InO X1 are mixed. In this specification, for example, when the atomic ratio of In to the element M in the first region is greater than the atomic ratio of In to the element M in the second region, it is considered that the concentration of In in the first region is higher than that in the second region compared with the second region.

[0209] Note that IGZO is a common name and may refer to a single compound of In, Ga, Zn, and O. As a representative example, InGaO 3 (ZnO) m1 (where m1 is a natural number), or In (1+x0) Ga (1-x0) O 3 (ZnO) m0 (-1 ≤ x0 ≤ 1, m0 is an arbitrary number), and crystalline compounds represented thereby can be mentioned.

[0210] The above crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. Note that the CAAC structure is a crystal structure in which a plurality of IGZO nanocrystals have c-axis orientation and are connected without orientation in the a-b plane.

[0211] On the other hand, CAC-OS relates to the material composition of metal oxides. CAC-OS refers to a structure in which, in a material composition containing In, Ga, Zn, and O, a region observed as nanoparticle-like with Ga as a main component and a region observed as nanoparticle-like with In as a main component are randomly dispersed in a mosaic pattern. Therefore, in CAC-OS, the crystal structure is a secondary element.

[0212] Note that CAC-OS does not include a laminated structure of two or more kinds of films having different compositions. For example, a structure composed of two layers of a film with In as a main component and a film with Ga as a main component is not included.

[0213] Note that the region where GaO X3 is the main component and the region where In X2 Zn Y2 O Z2 , or InO X1 is the main component may not have a clear boundary observable.

[0214] In addition, when one or more selected from aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium are included instead of gallium, CAC-OS refers to a configuration in which regions observed as nanoparticles mainly composed of the metal element and regions observed as nanoparticles mainly composed of In are randomly dispersed in a mosaic pattern, respectively.

[0215] CAC-OS can be formed by a sputtering method, for example, under conditions where the substrate is not intentionally heated. Also, when forming CAC-OS by the sputtering method, any one or more selected from inert gases (typically argon), oxygen gas, and nitrogen gas may be used as the film-forming gas. Further, the lower the flow rate ratio of oxygen gas to the total flow rate of the film-forming gas during film formation, the more preferable it is. For example, it is preferable that the flow rate ratio of oxygen gas is 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0216] CAC-OS has the characteristic that no distinct peak is observed when measured using θ / 2θ scan by the Out-of-plane method, which is one of the X-ray diffraction (XRD) measurement methods. That is, it can be seen from the X-ray diffraction measurement that there is no orientation in the a-b plane direction and the c-axis direction of the measurement region.

[0217] Also, in the electron diffraction pattern obtained by irradiating CAC-OS with an electron beam having a probe diameter of 1 nm (also referred to as a nano-beam electron beam), a bright ring-shaped region and a plurality of bright spots are observed within the ring-shaped region. Therefore, it can be seen from the electron diffraction pattern that the crystal structure of CAC-OS has an nc (nano-crystal) structure without orientation in the plane direction and the cross-sectional direction.

[0218] For example, in the case of CAC-OS in In-Ga-Zn oxide, according to the EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX), GaO X3 regions where it is the main component and In X2 Zn Y2 O Z2 , or regions where InO X1 is the main component are unevenly distributed and mixed, and it can be confirmed that they have a structure.

[0219] CAC-OS has a structure different from that of the IGZO compound in which metal elements are uniformly distributed and has properties different from those of the IGZO compound. That is, CAC-OS has a structure in which regions where GaO X3 etc. are the main components and regions where In X2 Zn Y2 O Z2 , or regions where InO X1 is the main component are phase-separated from each other, and regions with each element as the main component have a mosaic-like structure.

[0220] Here, regions where In X2 Zn Y2 O Z2 , or regions where InO X1 is the main component are regions with higher conductivity compared to regions where GaO X3 etc. are the main components. That is, when carriers flow through regions where In X2 Zn Y2 O Z2 , or regions where InO X1 is the main component, conductivity as a metal oxide is exhibited. Therefore, when regions where In X2 Zn Y2 O Z2 , or regions where InO X1 is the main component are distributed in a cloud-like manner in the metal oxide, high field-effect mobility (μ) can be realized.

[0221] On the other hand, regions where GaO X3 etc. are the main components are In X2 Zn Y2 O Z2 , or InOX1 It is a region with high insulation compared to the region where X1 is the main component. That is, the region where components such as GaO X3 are the main components are distributed in the metal oxide, suppressing the leakage current and enabling a good switching operation.

[0222] Therefore, when CAC-OS is used in a semiconductor device, the insulation caused by GaO X3 etc., and the conductivity caused by In X2 Zn Y2 O Z2 or InO X1 act complementarily to realize a high on-current (I on ) and a high field-effect mobility (μ).

[0223] Also, the semiconductor device using CAC-OS has high reliability. Therefore, CAC-OS is optimal for various semiconductor devices including displays.

[0224] In addition, since the transistor having CAC-OS in the semiconductor layer has a high field-effect mobility and a high driving ability, by using the transistor in a driving circuit, typically a scanning line driving circuit that generates a gate signal, a display device with a narrow frame width (also referred to as a narrow frame) can be provided. Also, by using the transistor in a signal line driving circuit of a display device (especially, a demultiplexer connected to the output terminal of a shift register included in the signal line driving circuit), a display device with a small number of wirings connected to the display device can be provided.

[0225] In addition, a transistor having CAC-OS in the semiconductor layer does not require a laser crystallization process like a transistor using low-temperature polysilicon. Therefore, even in a display device using a large-area substrate, it is possible to reduce the manufacturing cost. Further, in a high-resolution and large-sized display device such as ultra high vision ("4K resolution", "4K2K", "4K") and super high vision ("8K resolution", "8K4K", "8K"), by using a transistor having CAC-OS in the semiconductor layer for the drive circuit and the display section, writing can be performed in a short time, and display defects can be reduced, which is preferable.

[0226] Alternatively, silicon may be used for the semiconductor in which the channel of the transistor is formed. Although amorphous silicon may be used as the silicon, it is particularly preferable to use crystalline silicon. For example, it is preferable to use microcrystalline silicon, polycrystalline silicon, single crystal silicon, or the like. In particular, polycrystalline silicon can be formed at a lower temperature than single crystal silicon and has a higher field effect mobility and higher reliability than amorphous silicon.

[0227] 〔Conductive layer〕 In addition to the gate, source, and drain of a transistor, materials that can be used for conductive layers such as various wirings and electrodes constituting a display device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys having these as main components. Further, a film containing these materials can be used as a single layer or in a laminated structure. For example, a single-layer structure of an aluminum film containing silicon, a two-layer structure in which an aluminum film is laminated on a titanium film, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, a two-layer structure in which a copper film is laminated on a tungsten film, a three-layer structure in which a titanium film or a titanium nitride film is provided, an aluminum film or a copper film is laminated thereon, and a titanium film or a titanium nitride film is further formed thereon, a three-layer structure in which a molybdenum film or a molybdenum nitride film is provided, an aluminum film or a copper film is laminated thereon, and a molybdenum film or a molybdenum nitride film is further formed thereon, and the like. In addition, oxides such as indium oxide, tin oxide, or zinc oxide may be used. Further, the use of copper containing manganese is preferable because it enhances the controllability of the shape by etching.

[0228] 〔Insulating layer〕 Examples of insulating materials that can be used for each insulating layer include resins such as acrylic and epoxy, resins having a siloxane bond, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxynitride, silicon nitride, and aluminum oxide.

[0229] Further, it is preferable that the light-emitting element is provided between a pair of insulating films having low water permeability. Thereby, it is possible to suppress the intrusion of impurities such as water into the light-emitting element and suppress a decrease in the reliability of the display device.

[0230] Examples of the low-permeability insulating film include films containing nitrogen and silicon such as silicon nitride films and silicon oxynitride films, and films containing nitrogen and aluminum such as aluminum nitride films. Further, silicon oxide films, silicon oxynitride films, aluminum oxide films, etc. may also be used.

[0231] For example, the water vapor transmission rate of the low-permeability insulating film is 1×10 -5 [g / (m 2 ·day)] or less, preferably 1×10 -6 [g / (m 2 ·day)] or less, more preferably 1×10 -7 [g / (m 2 ·day)] or less, still more preferably 1×10 -8 [g / (m 2 ·day)] or less.

[0232] The above is the description of the components.

[0233] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc. can be implemented by appropriately combining at least a part of them with other configuration examples, drawings, etc.

[0234] This embodiment can be implemented by appropriately combining at least a part of it with other embodiments described in this specification.

[0235] (Embodiment 3) In this embodiment, a configuration example of the display device will be described with reference to FIGS. 16A to 16C.

[0236] The display device shown in FIG. 16A includes a pixel portion 502, a drive circuit portion 504, a protection circuit 506, and a terminal portion 507. Note that the protection circuit 506 may not be provided.

[0237] The pixel portion 502 includes a plurality of pixel circuits 501 that drive a plurality of display elements arranged in X rows and Y columns (X and Y are each independently a natural number of 2 or more).

[0238] The drive circuit section 504 includes drive circuits such as a gate driver 504a that outputs a scanning signal to gate lines GL_1 to GL_X and a source driver 504b that supplies a data signal to data lines DL_1 to DL_Y. The gate driver 504a may be configured to have at least a shift register. The source driver 504b may be configured using, for example, a plurality of analog switches. Alternatively, the source driver 504b may be configured using a shift register or the like.

[0239] The terminal section 507 refers to a portion where terminals for inputting power, a control signal, an image signal, etc. from an external circuit to the display device are provided.

[0240] The protection circuit 506 is a circuit that makes a wiring to which it is connected and another wiring in a conductive state when a potential outside a certain range is applied to the wiring to which it is connected. The protection circuit 506 shown in FIG. 16A is connected to various wirings such as a gate line GL which is a wiring between the gate driver 504a and the pixel circuit 501, or a data line DL which is a wiring between the source driver 504b and the pixel circuit 501. In FIG. 16A, hatching is applied to the protection circuit 506 to distinguish it from the pixel circuit 501.

[0241] Also, the gate driver 504a and the source driver 504b may be provided on the same substrate as the pixel section 502, or a substrate on which a gate driver circuit or a source driver circuit is separately formed (for example, a drive circuit substrate formed of a single crystal semiconductor or a polycrystalline semiconductor) may be mounted on the substrate on which the pixel section 502 is provided by COG or TAB (Tape Automated Bonding).

[0242] Also, the plurality of pixel circuits 501 shown in FIG. 16A can be configured, for example, as shown in FIG. 16B or FIG. 16C.

[0243] The pixel circuit 501 shown in FIG. 16B includes a liquid crystal element 570, a transistor 550, and a capacitor element 560. Further, a data line DL_n, a gate line GL_m, a potential supply line VL, etc. are connected to the pixel circuit 501.

[0244] One of the potentials of the pair of electrodes of the liquid crystal element 570 is appropriately set according to the specifications of the pixel circuit 501. The alignment state of the liquid crystal element 570 is set by the data to be written. Note that a common potential (common potential) may be applied to one of the pair of electrodes of the liquid crystal element 570 included in each of the plurality of pixel circuits 501. Alternatively, different potentials may be applied to one of the pair of electrodes of the liquid crystal element 570 of the pixel circuits 501 in each row.

[0245] Further, the pixel circuit 501 shown in FIG. 16C includes a transistor 552, a transistor 554, a capacitor element 562, and a light-emitting element 572. Further, a data line DL_n, a gate line GL_m, a potential supply line VL_a, and a potential supply line VL_b, etc. are connected to the pixel circuit 501.

[0246] Note that a high power supply potential VDD is applied to one of the potential supply line VL_a and the potential supply line VL_b, and a low power supply potential VSS is applied to the other. The current flowing through the light-emitting element 572 is controlled according to the potential applied to the gate of the transistor 554, thereby controlling the emission luminance from the light-emitting element 572.

[0247] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc. can be implemented by appropriately combining at least a part of them with other configuration examples, or drawings, etc.

[0248] This embodiment can be implemented by appropriately combining at least a part of it with other embodiments described in this specification.

[0249] (Embodiment 4) Hereinafter, a pixel circuit including a memory for correcting the gradation of a pixel and a display device having the same will be described.

[0250] [Circuit Configuration] FIG. 17A shows a circuit diagram of the pixel circuit 400. The pixel circuit 400 includes a transistor M1, a transistor M2, a capacitor C1, and a circuit 401. Further, wiring S1, wiring S2, wiring G1, and wiring G2 are connected to the pixel circuit 400.

[0251] One of the gate of the transistor M1 is connected to the wiring G1, one of the source and drain is connected to the wiring S1, and the other is connected to one electrode of the capacitor C1. One of the gate of the transistor M2 is connected to the wiring G2, one of the source and drain is connected to the wiring S2, and the other is connected to the other electrode of the capacitor C1 and the circuit 401.

[0252] The circuit 401 is a circuit including at least one display element. Although various elements can be used as the display element, typically, a light-emitting element such as an organic EL element or an LED element, a liquid crystal element, or a MEMS (Micro Electro Mechanical Systems) element can be applied.

[0253] Let the node connecting the transistor M1 and the capacitor C1 be node N1, and the node connecting the transistor M2 and the circuit 401 be node N2.

[0254] The pixel circuit 400 can hold the potential of the node N1 by turning off the transistor M1. Also, the potential of the node N2 can be held by turning off the transistor M2. Further, with the transistor M2 turned off, by writing a predetermined potential to the node N1 via the transistor M1, the potential of the node N2 can be changed according to the change in the potential of the node N1 by capacitive coupling through the capacitor C1.

[0255] Here, a transistor in which an oxide semiconductor is applied can be applied to one or both of the transistors M1 and M2. Therefore, due to an extremely low off-current, the potential of the node N1 or the node N2 can be held for a long period of time. When the period for holding the potential of each node is short (specifically, when the frame frequency is 30 Hz or more, etc.), a transistor using a semiconductor such as silicon may be used.

[0256] [Example of driving method] Next, an example of the operation method of the pixel circuit 400 will be described with reference to FIG. 17B. FIG. 17B is a timing chart related to the operation of the pixel circuit 400. Here, for ease of explanation, effects such as various resistances such as wiring resistance, parasitic capacitances of transistors and wirings, and threshold voltages of transistors are not considered.

[0257] In the operation shown in FIG. 17B, one frame period is divided into a period T1 and a period T2. The period T1 is a period for writing a potential to the node N2, and the period T2 is a period for writing a potential to the node N1.

[0258] [Period T1] In the period T1, potentials for turning on the transistors are applied to both the wiring G1 and the wiring G2. Also, a potential V ref which is a fixed potential is supplied to the wiring S1, and a first data potential V w is supplied to the wiring S2.

[0259] The potential V ref is applied to the node N1 from the wiring S1 via the transistor M1. Also, the first data potential V w is applied to the node N2 from the wiring S2 via the transistor M2. Therefore, a potential difference V w -V ref is held in the capacitor C1.

[0260] [Period T2] Subsequently, in period T2, a potential that turns on transistor M1 is applied to wiring G1, and a potential that turns off transistor M2 is applied to wiring G2. Also, a second data potential V data is supplied to wiring S1. A predetermined fixed potential may be applied to wiring S2, or it may be in a floating state.

[0261] At node N1, the second data potential V data is applied from wiring S1 through transistor M1. At this time, due to capacitive coupling by capacitor C1, the potential of node N2 changes by an amount dV according to the second data potential V data . That is, a potential obtained by adding the first data potential V w and the potential dV is input to circuit 401. Note that in FIG. 17B, the potential dV is shown as a positive value, but it may be a negative value. That is, the second data potential V data may be lower than the potential V ref .

[0262] Here, the potential dV is generally determined by the capacitance value of capacitor C1 and the capacitance value of circuit 401. When the capacitance value of capacitor C1 is sufficiently larger than the capacitance value of circuit 401, the potential dV becomes a potential close to the second data potential V data .

[0263] In this way, pixel circuit 400 can generate a potential to be supplied to circuit 401 including a display element by combining two types of data signals, so that gradation correction can be performed within pixel circuit 400.

[0264] Also, pixel circuit 400 can generate a potential exceeding the maximum potential that can be supplied by a source driver connected to wiring S1 and wiring S2. For example, when a light-emitting element is used, high dynamic range (HDR) display or the like can be performed. Also, when a liquid crystal element is used, overdrive driving or the like can be realized.

[0265] [Application Example] [Example Using a Liquid Crystal Element] The pixel circuit 400LC shown in FIG. 17C has a circuit 401LC. The circuit 401LC has a liquid crystal element LC and a capacitor C2.

[0266] One electrode of the liquid crystal element LC is connected to the node N2 and one electrode of the capacitor C2, and the other electrode is connected to a wiring to which a potential V com2 is applied. The other electrode of the capacitor C2 is connected to a wiring to which a potential V com1 is applied.

[0267] The capacitor C2 functions as a holding capacitor. If the capacitor C2 is not necessary, it can be omitted.

[0268] Since the pixel circuit 400LC can supply a high voltage to the liquid crystal element LC, for example, high-speed display can be realized by overdrive driving, and a liquid crystal material with a high driving voltage can be applied. Also, by supplying a correction signal to the wiring S1 or the wiring S2, gradation can be corrected according to the use temperature, the deterioration state of the liquid crystal element LC, etc.

[0269] 〔Example using a light-emitting element〕 The pixel circuit 400EL shown in FIG. 17D has a circuit 401EL. The circuit 401EL has a light-emitting element EL, a transistor M3, and a capacitor C2.

[0270] The gate of the transistor M3 is connected to the node N2 and one electrode of the capacitor C2, one of the source and the drain is connected to a wiring to which a potential V H is applied, and the other is connected to one electrode of the light-emitting element EL. The other electrode of the capacitor C2 is connected to a wiring to which a potential V com is applied. The other electrode of the light-emitting element EL is connected to a wiring to which a potential V L is applied.

[0271] The transistor M3 has a function of controlling the current supplied to the light-emitting element EL. The capacitor C2 functions as a holding capacitor. If the capacitor C2 is not necessary, it can be omitted.

[0272] Note that, although the configuration where the anode side of the light-emitting element EL is connected to the transistor M3 is shown here, the transistor M3 may be connected to the cathode side. In that case, the values of the potential V H and the potential V L can be appropriately changed.

[0273] By applying a high potential to the gate of the transistor M3, the pixel circuit 400EL can cause a large current to flow through the light-emitting element EL, so that, for example, HDR display or the like can be realized. Further, by supplying a correction signal to the wiring S1 or the wiring S2, it is also possible to correct variations in the electrical characteristics of the transistor M3 and the light-emitting element EL.

[0274] Note that the circuit is not limited to the circuits illustrated in FIGS. 17C and 17D, and a configuration in which transistors, capacitors, or the like are additionally provided separately may be used.

[0275] This embodiment can be implemented in appropriate combination with at least a part of other embodiments described in this specification.

[0276] (Embodiment 5) Hereinafter, a configuration example of a pixel of a display device according to an aspect of the present invention will be described.

[0277] FIGS. 18A to 18E show a configuration example of the pixel 300.

[0278] The pixel 300 includes a plurality of pixels 301. The plurality of pixels 301 each function as a sub-pixel. One pixel 300 is constituted by a plurality of pixels 301 each presenting a different color, so that a full-color display can be performed on the display unit.

[0279] The pixels 300 shown in FIGS. 18A and 18B each have three sub-pixels. The combination of colors presented by the pixels 301 included in the pixel 300 shown in FIG. 18A is red (R), green (G), and blue (B). The combination of colors presented by the pixels 301 included in the pixel 300 shown in FIG. 18B is cyan (C), magenta (M), and yellow (Y).

[0280] The pixels 300 shown in FIGS. 18C to 18E each have four sub-pixels. The combination of colors presented by the pixel 301 included in the pixel 300 shown in FIG. 18C is red (R), green (G), blue (B), and white (W). By using the sub-pixel presenting white, the luminance of the display unit can be increased. The combination of colors presented by the pixel 301 included in the pixel 300 shown in FIG. 18D is red (R), green (G), blue (B), and yellow (Y). The combination of colors presented by the pixel 301 included in the pixel 300 shown in FIG. 18E is cyan (C), magenta (M), yellow (Y), and white (W).

[0281] By increasing the number of sub-pixels functioning as one pixel and appropriately combining sub-pixels presenting colors such as red, green, blue, cyan, magenta, and yellow, the reproducibility of gradation can be enhanced. Therefore, the display quality can be improved.

[0282] In addition, the display device according to one aspect of the present invention can reproduce color gamuts of various standards. For example, it can reproduce the PAL (Phase Alternating Line) standard and NTSC (National Television System Committee) standard used in television broadcasting, the sRGB (standard RGB) standard and Adobe RGB standard widely used in display devices for electronic devices such as personal computers, digital cameras, and printers, the ITU-R BT.709 (International Telecommunication Union Radiocommunication Sector Broadcasting Service (Television) 709) standard used in HDTV (High Definition Television, also called high vision), the DCI-P3 (Digital Cinema Initiatives P3) standard used in digital cinema projection, the ITU-R BT.2020 (REC.2020 (Recommendation 2020)) standard used in UHDTV (Ultra High Definition Television, also called super high vision), and other color gamuts.

[0283] Also, when the pixels 300 are arranged in a 1920×1080 matrix, a display device capable of full-color display with a so-called full high vision (also referred to as "2K resolution", "2K1K", or "2K") resolution can be realized. Further, for example, when the pixels 300 are arranged in a 3840×2160 matrix, a display device capable of full-color display with a so-called ultra high vision (also referred to as "4K resolution", "4K2K", or "4K") resolution can be realized. Further, for example, when the pixels 300 are arranged in a 7680×4320 matrix, a display device capable of full-color display with a so-called super high vision (also referred to as "8K resolution", "8K4K", or "8K") resolution can be realized. By increasing the number of pixels 300, it is also possible to realize a display device capable of full-color display with a resolution of 16K or 32K.

[0284] This embodiment can be implemented in appropriate combination with at least some of the other embodiments described in this specification as appropriate.

Description of Reference Numerals

[0285] 10: Display device, 11: Display panel, 12: Protection cover, 12a, 12b, 13: Functional layer, 14: Protection cover, 14a, 14b: Functional layer, 15: Display unit, 21, 22: Support, 23, 23a, 23b: Holding member, 24, 24a, 24b: Spacer, 28: Region, 29: Stylus, 31, 32: Gear, 31a, 32a: Rotation shaft, 33: Cover, 41, 41a, 41b: Spring, 42: Movable member, 43: Adhesive member

Claims

1. The display device includes a display panel, a protective cover, and a holding member. the display panel and the protective cover have a curved portion provided along one direction of the display panel, an end of the display panel is misaligned with an end of the protective cover in a cross-sectional view taken along a direction intersecting the curved portion; In a cross-sectional view taken along a direction intersecting the curved portion, the end of the display panel is misaligned with an end of the holding member, A display device, wherein the curved portion of the display panel functions to allow the display panel to be flat when unfolded.

2. The display device includes a display panel, a protective cover, and a holding member. the display panel has a touch sensor on a surface on which the protective cover is provided, The display panel and the protective cover are curved in the same direction, In a cross-sectional view taken along a direction intersecting a curved portion, an end of the display panel does not coincide with an end of the protective cover, In a cross-sectional view taken along a direction intersecting the curved portion, the end of the display panel does not coincide with an end of the holding member, A display device, wherein the curved portion of the display panel functions to allow the display panel to be flat when unfolded.

3. In claim 1 or 2, the end of the holding member protrudes outward beyond the end of the display panel, A display device, wherein the end of the holding member protrudes outward beyond the end of the protective cover.

4. In any one of claims 1 to 3, The display device, wherein the holding member is provided so as to surround a display portion of the display panel.

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