Indication device

Abstract

Improve the performance of the display device. [Solution] A display device comprising a first substrate, a second substrate opposite the first substrate, a liquid crystal layer provided between the first substrate and the second substrate, a light source unit provided outside the area where the liquid crystal layer is provided in a planar view, and heater wiring, wherein the heater wiring has a first position and a second position, the distance from the first position to the light source unit is smaller than the distance from the second position to the light source unit, and the cross-sectional area of ​​the heater wiring perpendicular to the longitudinal direction at the first position is larger than the cross-sectional area of ​​the heater wiring perpendicular to the longitudinal direction at the second position.

Description

[Technical Field]

[0001] The present invention relates to a display device. [Background technology]

[0002] Patent Document 1 (JP 2006-47455 A) describes a liquid crystal display device for vehicles that includes a liquid crystal panel and a transparent planar heater in which a transparent conductive film for generating heat is formed on one side of a transparent planar substrate.Patent Document 2 (JP 2023-167697 A) describes a display device that includes an array substrate that includes a display area in which pixels are arranged and a peripheral area outside the display area. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-47455 [Patent Document 2] Japanese Patent Application Publication No. 2023-167697 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as the ambient temperature decreases, the fall response speed of the liquid crystal decreases, which causes a problem of a decrease in the performance of the display device. Therefore, an object of the present invention is to improve the performance of the display device.

[0005] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0006] a first substrate, a second substrate opposite the first substrate, a liquid crystal layer provided between the first substrate and the second substrate, a light source unit provided outside an area where the liquid crystal layer is provided in a planar view, and a heater wiring, wherein the heater wiring has a first position and a second position, the distance from the first position to the light source unit is smaller than the distance from the second position to the light source unit, and the cross-sectional area of ​​the heater wiring perpendicular to the longitudinal direction at the first position is larger than the cross-sectional area of ​​the heater wiring perpendicular to the longitudinal direction at the second position. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram showing the positional relationship when a viewer on one side of a transparent display panel views a background on the opposite side through the transparent display panel. [Figure 2] FIG. 2 is an explanatory diagram showing an example of a background that is visible through a transparent display panel. [Figure 3] FIG. 3 is a perspective view showing an example of a display device. [Figure 4] FIG. 4 is a plan view of the display device shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view of the display device shown in FIG. [Figure 6] FIG. 6 is a circuit block diagram showing an example of a circuit included in the display device shown in FIG. [Figure 7] FIG. 7 is a plan view of the display device. [Figure 8] FIG. 8 is a plan view of the display device. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. The disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, in order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0009] In this application, the description of the embodiments will be divided into multiple sections, etc., for convenience, as necessary. However, unless otherwise expressly stated, these are not mutually independent and separate, and regardless of the order of description, they are each part of a single example, one being a partial detail of the other, or a partial or complete modification, etc. Furthermore, as a general rule, repeated explanations of similar parts will be omitted. Furthermore, each component in the embodiments is not essential unless otherwise expressly stated, there is a theoretical limit to the number, or it is clearly not essential from the context.

[0010] In the accompanying drawings, hatching may be omitted even in cross sections if it would be too complicated or if the distinction from voids is clear. In relation to this, background contour lines may be omitted even in the case of holes that are closed in plan view if it is clear from the description, etc. Furthermore, hatching or dot patterns may be added even in cases where the drawing is not a cross section to clearly indicate that the hole is not a void or to clearly indicate the boundary of the area.

[0011] A display device according to this embodiment will be described. The display device according to this embodiment has a transparent display panel. First, the characteristics of the transparent display panel will be described. FIG. 1 is an explanatory diagram showing the positional relationship when a viewer on one side of a transparent display panel views a background on the opposite side through the transparent display panel. FIG. 2 is an explanatory diagram showing an example of a background viewed through the transparent display panel.

[0012] As shown in FIG. 1, when a viewer 100 views the display panel P1 from one side to the other, a background 111 is viewed through the display panel P1. As shown in FIG. 2, if the display area DA (PIX) and the peripheral area PFA outside the display area DA are both light-transmitting, the entire background 111 can be viewed without any sense of incongruity. On the other hand, if the peripheral area PFA has a light-blocking property that does not transmit light, a portion of the background 111 viewed through the display panel P1 is blocked by the peripheral area PFA, which may cause the viewer 100 to feel uneasy. As such, in the case of the display panel P1, which is a transparent display panel, it is preferable that the display area DA and the peripheral area PFA each have visible light transmittance. Furthermore, from the viewpoint of viewing the background 111 without any sense of incongruity, it is particularly preferable that the visible light transmittance characteristics of the display area DA and the peripheral area PFA are approximately the same.

[0013] FIG. 3 is a perspective view showing an example of a display device. FIG. 4 is a plan view of the display device shown in FIG. 3. In FIG. 3, the boundary between the display area DA and the peripheral area PFA is indicated by a two-dot chain line. Also, in FIG. 3, part of the signal wiring (more specifically, gate wiring GL and source wiring SL) that transmits signals for driving liquid crystal, among the circuits included in the display panel P1, is schematically indicated by a one-dot chain line. In the following drawings including FIG. 3, the direction along the thickness direction of the display panel P1 is referred to as the Z direction, the extension direction of one side of the display panel P1 in an XY plane perpendicular to the Z direction is referred to as the X direction, and the direction intersecting the X direction is referred to as the Y direction. Also, the direction indicated by the arrow of the Z coordinate in the drawings may be referred to as "up." Also, the direction opposite to the direction indicated by the arrow of the Z coordinate in the drawings may be referred to as "down."

[0014] As shown in FIGS. 3 and 4, the display device 1A according to this embodiment includes a display panel P1, a light source section 30, and a drive circuit .

[0015] When configured as a display device, in addition to the components of the display panel P1 shown in Fig. 3, it may also include, for example, a flexible substrate connected to the display panel P1, a housing, etc. Components other than the display panel P1 are not shown in Fig. 3. Furthermore, the display device 1A according to this embodiment does not need to have a polarizing plate.

[0016] The display panel P1 has a display area DA where an image is formed in response to an externally supplied input signal, and a peripheral area (frame area) PFA surrounding the display area DA. While the display area DA of the display panel P1 shown in FIG. 3 is rectangular, the display area DA may be a shape other than rectangular, such as a polygon or a circle. The display area DA is the effective area where the display panel P1 displays an image, as viewed from the top of the display surface. In FIG. 3, the display surface is parallel to the XY plane. In the example shown in FIG. 3, the light source unit 30 and the drive circuit 40 are mounted on the display panel P1. However, in a modified example, a light source substrate (not shown) separate from the display panel P1 may be attached to the peripheral area PFA of the display panel P1, and the light source unit 30 may be mounted on the light source substrate (not shown).

[0017] <Display panel> The configuration of the display panel P1 will be described. Fig. 5 is a cross-sectional view of the display device shown in Fig. 4. Fig. 5 is a cross-sectional view taken along line AA in Fig. 4. That is, Fig. 5 is a cross-sectional view of the display panel of the display device shown in Fig. 4 taken along a plane perpendicular to the Y direction. Although Fig. 5 is a cross-sectional view, hatching of each component except for the liquid crystal layer LQL is omitted.

[0018] As shown in FIG. 5, the display panel P1 includes an array substrate 10, a counter substrate 20, a front cover substrate 52, a back cover substrate 51, an adhesive layer 80, a liquid crystal layer LQL, an alignment film 70, a planarization layer 60, heater wiring HL, and a light-shielding material BM.

[0019] Although the array substrate 10 may simply be referred to as a substrate, hereinafter, it will be referred to as the array substrate 10 to refer to a substrate on which a plurality of switching elements are arranged in an array. As shown in FIG. 5, the array substrate 10 has an upper surface and a lower surface opposite the upper surface. The upper surface and the lower surface of the array substrate 10 are spaced apart from each other. The array substrate 10 also has a side surface provided between the upper surface and the lower surface. In this embodiment, the array substrate 10 is a TFT (Thin Film Transistor) substrate. As shown in FIG. 5, the array substrate 10 has source lines SL and gate lines GL. As shown in FIG. 5, the source lines SL are provided on the upper surface of the array substrate 10. The source lines SL are in contact with the upper surface of the array substrate 10. The array substrate 10 is transparent to visible light. The array substrate 10 may be provided with switching elements (active elements) Tr, which will be described later. The thickness of the array substrate 10 is, for example, 0.1 mm to 10 mm. The source lines SL shown in FIG. 5 are lines for transmitting video signals. The gate lines GL shown in FIG. 5 are lines for transmitting scanning signals.

[0020] In FIG. 4, when the display panel P1 is viewed in a plan view, the light L1 emitted from the light source unit 30 appears to travel along the Y direction. Furthermore, in FIG. 5, when the XZ plane is viewed in a plan view, the light L1 emitted from the light source unit 30 appears to travel along the Z direction while repeatedly undergoing total reflection. As shown in FIG. 5, the source lines SL are arranged along the Y direction. That is, when the display panel P1 is viewed in a plan view, the source lines SL are arranged along the traveling direction of the light emitted from the light source unit 30. Furthermore, as shown in FIG. 5, when the display panel P1 is viewed in a plan view, the gate lines GL are arranged to intersect with the source lines SL. In this embodiment, the source lines SL and the gate lines GL are orthogonal to each other. The source lines SL and the gate lines GL are spaced apart from each other. The source lines SL are electrically isolated from the gate lines GL. Here, viewing the display panel P1 in a plan view refers to viewing the XY plane of FIG. 4 in a plan view.

[0021] As shown in FIG. 5, the counter substrate 20 is spaced apart from the array substrate 10. Although the counter substrate 20 can be simply referred to as a substrate, hereinafter it will be referred to as the counter substrate 20, meaning a substrate disposed opposite the array substrate 10. The counter substrate 20 has an upper surface and a lower surface opposite the upper surface. The upper surface and the lower surface of the counter substrate 20 are spaced apart from each other. The counter substrate 20 also has side surfaces provided between the upper surface and the lower surface. As shown in FIG. 5, the lower surface of the counter substrate 20 faces the upper surface of the array substrate 10. The counter substrate 20 is transparent to visible light. The thickness of the counter substrate 20 is, for example, 0.1 mm or more and 10 mm or less.

[0022] The counter substrate 20 is bonded to, for example, the array substrate 10 via a seal portion (sealing material). The seal portion (sealing material) bonds the array substrate 10 and the counter substrate 20 together. The seal portion bonds the upper surface of the array substrate 10 to the lower surface of the counter substrate 20 together. The seal portion is provided, for example, to surround the outer periphery of the liquid crystal layer LQL. The seal portion surrounds the entire liquid crystal layer LQL together with the array substrate 10 and the counter substrate 20. In other words, the liquid crystal layer LQL is located inside the seal portion. The seal portion serves as a seal that seals the liquid crystal layer LQL between the array substrate 10 and the counter substrate 20. The seal portion also serves as an adhesive that bonds the array substrate 10 and the counter substrate 20 together.

[0023] As shown in FIG. 5, the liquid crystal layer LQL is provided between the upper surface of the array substrate 10 and the lower surface of the counter substrate 20. The liquid crystal layer LQL includes a liquid crystal LQ. The liquid crystal layer LQL is an optical modulation element that can change the light transmission state by electrically driving the alignment state of the liquid crystal. The display panel P1 has a function of driving the alignment state of the liquid crystal molecules and modulating the light L1 passing therethrough by controlling the state of the electric field formed around the liquid crystal layer LQL via the above-mentioned switching element.

[0024] The liquid crystal LQ is a polymer-dispersed liquid crystal LC, which contains a liquid crystal polymer and liquid crystal molecules. The liquid crystal polymer is formed into stripes, and the liquid crystal molecules are dispersed in the gaps between the liquid crystal polymer. The liquid crystal polymer and the liquid crystal molecules each have optical anisotropy or refractive index anisotropy. The response of the liquid crystal polymer to an electric field is lower than that of the liquid crystal molecules. The orientation direction of the liquid crystal polymer hardly changes regardless of the presence or absence of an electric field.

[0025] On the other hand, when a high voltage equal to or greater than the threshold is applied to the liquid crystal LQ, the alignment direction of the liquid crystal molecules changes in response to the electric field. When no voltage is applied to the liquid crystal LQ, the optical axes of the liquid crystal polymer and the liquid crystal molecules are parallel to each other. Therefore, light L1 incident on the liquid crystal layer LQL is transmitted through the liquid crystal layer LQL with almost no scattering within the liquid crystal layer LQL (transparent state). When a voltage is applied to the liquid crystal LQ, the optical axes of the liquid crystal polymer and the liquid crystal molecules intersect with each other. Therefore, light L1 incident on the liquid crystal LQ is scattered within the liquid crystal layer LQL (scattered state).

[0026] The display panel P1 controls the orientation of the liquid crystal LQ in the propagation path of the light L1 to switch between a transparent state and a scattering state. In the scattering state, the light L1 is emitted from the liquid crystal LQ as emitted light L2 to the outside of the display panel P1 from the upper surface side of the front cover substrate 52. Furthermore, background light L3 incident from the lower surface side of the rear cover substrate 51 passes through the array substrate 10, the liquid crystal layer LQL, the counter substrate 20, and the front cover substrate 52, and is emitted to the outside from the upper surface of the front cover substrate 52. The emitted light L2 and background light L3 are visible to a viewer standing on the upper surface side of the front cover substrate 52. The viewer can perceive the emitted light L2 and the background light L3 in combination. In this way, the transparent display panel P1 is a display panel P1 that allows the viewer to perceive a display image and a background superimposed on each other.

[0027] 5, the alignment film 71 is provided between the upper surface of the array substrate 10 and the liquid crystal layer LQL. The alignment film 71 can align the liquid crystal molecules of the liquid crystal LQ. The alignment film 71 is in contact with the liquid crystal LQ of the liquid crystal layer LQL.

[0028] The light-shielding material BM is provided on the lower surface of the counter substrate 20. The light-shielding material BM is provided along the source lines SL. When the display panel P1 is viewed in a plan view, the position of the light-shielding material BM overlaps the position of the source lines SL. When the display panel P1 is viewed in a plan view, it is preferable that the width of the light-shielding material BM is greater than the width of the source lines SL. When the display panel P1 is viewed in a plan view, it is preferable that the source lines SL are arranged within the area where the light-shielding material BM is located. The light-shielding material BM is formed of, for example, a black resin or a metal material. Examples of metal materials include copper, aluminum, chromium, molybdenum, titanium, and Al alloys.

[0029] As shown in Fig. 5, the alignment film 72 is provided between the lower surface of the counter substrate 20 and the liquid crystal layer LQL. The alignment film 72 can align the liquid crystal molecules of the liquid crystal LQ. The alignment film 72 is in contact with the liquid crystal LQ of the liquid crystal layer LQL. Hereinafter, the alignment film 71 and the alignment film 72 may be collectively referred to as the alignment film 70.

[0030] As shown in FIG. 5 , the back cover substrate 51 has an upper surface 51a and a lower surface opposite the upper surface. The back cover substrate 51 and the front cover substrate 52 described later can each be simply referred to as a substrate. However, in the following, to distinguish between the two, they will be referred to as the back cover substrate 51 and the front cover substrate 52. The upper and lower surfaces are spaced apart. The back cover substrate 51 also has a side surface provided between the upper and lower surfaces. In this embodiment, the back cover substrate 51 is made of glass. In other words, the back cover substrate 51 is a glass substrate made of glass. The back cover substrate 51 is transparent to visible light. Examples of materials for the back cover substrate 51 include glass, as well as organic materials such as acrylic resin or polycarbonate resin. The thickness of the back cover substrate 51 is, for example, 0.5 mm to 10 mm.

[0031] In this embodiment, the cross-sectional area of ​​the heater wiring HL perpendicular to the longitudinal direction at position R1 is larger than the cross-sectional area of ​​the heater wiring HL perpendicular to the longitudinal direction at position R2. Here, the distance between position R1 and the light source 30 is smaller than the distance between position R2 and the light source 30. Furthermore, the cross-sectional area of ​​the heater wiring HL perpendicular to the longitudinal direction decreases with increasing distance from the light source 30. In other words, the resistance of the heater wiring HL at position R1 is smaller than the resistance of the heater wiring HL at position R2. In other words, the resistance value of the heater wiring HL increases with increasing distance from the light source 30. Furthermore, as shown in FIG. 4, the width of the heater wiring HL at position R1 may be larger than the width of the heater wiring HL at position R2 in a plan view.

[0032] As shown in FIG. 4, the heater wiring HL is arranged along the Y direction. That is, when the display panel P1 is viewed in a plan view, the heater wiring HL is arranged parallel to the light incident direction. Here, the light incident direction refers to the direction in which light emitted from the light source unit 30 enters the display panel P1 when the display panel P1 is viewed in a plan view. In the example shown in FIG. 4, the light incident direction refers to the direction in which light emitted from the light source unit 30 enters the side surface of the front cover substrate 52 when the display panel P1 is viewed in a plan view. That is, in the example shown in FIG. 4, the light incident direction is the Y direction.

[0033] 4, the heater wire HL is electrically connected to a terminal 201 and a terminal 202. The terminals 201 and 202 are also connected to a power supply unit 210. This causes a current to flow through the heater wire HL.

[0034] As shown in FIG. 5, the heater wire HL is provided on the upper surface 51a of the back cover substrate 51. The heater wire HL is in contact with the upper surface 51a of the back cover substrate 51. The heater wire HL includes a metal. The heater wire HL includes, for example, a simple metal or an alloy. Examples of the simple metal include copper and aluminum. Examples of the alloy include an Al alloy (aluminum alloy). The heater wire HL may include not only a single phase but also multiple layers. The heater wire HL includes, for example, a metal wire and a coating layer that covers the outer surface of the metal wire.

[0035] In this embodiment, the heater lines HL are provided along the source lines SL. When the display panel P1 is viewed in plan, the heater lines HL overlap with the source lines SL.

[0036] The heater wiring HL is a heater that uses a resistance heating method. That is, when a current flows through the heater wiring HL, the heater wiring HL can generate heat. When the display panel P1 is viewed in plan, the width of the heater wiring HL is, for example, 0.05 μm or more and 10 μm or less. Furthermore, the thickness of the heater wiring HL is preferably 1 μm or more and 5 μm or less. When the thickness of the heater wiring HL is 1 μm or more and 5 μm or less, a thicker thickness is preferable because the resistance of the heater wiring HL is lower. This allows a larger current to flow through the heater wiring HL even with the same applied voltage. This further increases the heating capacity of the heater wiring HL. The thickness of the heater wiring HL is more preferably 0.1 μm or more and 1 μm or less, and even more preferably 0.3 μm or more and 0.7 μm or less. This makes it difficult for the heater wiring HL to scatter light emitted from the light source unit 30.

[0037] The planarization layer 60 is provided on the upper surface 51a of the back cover substrate 51. The planarization layer 60 is provided so as to cover the heater wires HL. The planarization layer 60 has an upper surface and a lower surface opposite the upper surface. The lower surface of the planarization layer 60 is in contact with the back cover substrate 51. Because the planarization layer 60 covers the heater wires HL, the upper surface of the planarization layer 60 and the heater wires HL are spaced apart from each other. In other words, the thickness of the planarization layer 60 is greater than the thickness of the heater wires HL. This protects the heater wires HL. This prevents the heater wires HL, which contain metal, from corroding with, for example, the adhesive layer 81. Furthermore, when the heater wires HL are provided on the upper surface 51a of the back cover substrate 51, a step is formed. By providing the planarization layer 60 so as to cover the heater wires HL, the step can be reduced. This makes it easier to attach the back cover substrate 51 provided with the heater wires HL to another base material. The thickness of the planarizing layer 60 is preferably 1 to 10 times, and more preferably 1.5 to 5 times, the thickness of the heater wiring HL, which allows the thickness of the display panel P1 to be reduced.

[0038] In the edge-lit display device 1A, there is a possibility that light may pass through the planarization layer 60 multiple times. Therefore, it is preferable that the planarization layer 60 be made of a material that absorbs as little light as possible and has small wavelength dispersion. The planarization layer 60 is formed so as to cover the base substrate (e.g., the back cover substrate 51) on which a pattern (e.g., heater wiring HL) is formed. The planarization layer 60 is an insulating layer made of, for example, an organic insulating material. It has the function of planarizing unevenness caused by the pattern formed on the base substrate. In the example shown in FIG. 5, the planarization layer 60 is also called an overcoat layer.

[0039] As shown in FIG. 5 , the adhesive layer 81 is provided between the lower surface of the array substrate 10 and the upper surface of the planarization layer 60. The adhesive layer 81 has an upper surface and a lower surface 81b opposite to the upper surface. The upper surface of the adhesive layer 81 contacts the lower surface of the array substrate 10. The lower surface 81b of the adhesive layer 81 contacts the upper surface of the planarization layer 60. The adhesive layer 81 serves to bond the array substrate 10 and the planarization layer 60 together. The adhesive layer 81 fixes the planarization layer 60 and the back cover substrate 51 to the array substrate 10. The adhesive layer 81 has visible light transmissive properties. The refractive index of the adhesive layer 81 is preferably closer to the refractive index of the planarization layer 60 and the array substrate 10 than that of air. By making the refractive index of the adhesive layer 81 equivalent to that of the planarization layer 60 and the array substrate 10, reflection of light L1 at the interfaces between the adhesive layer 81 and the upper surface of the planarization layer 60 and the lower surface of the array substrate 10 can be suppressed. Examples of the adhesive layer 81 include a transparent adhesive sheet called OCA (Optical Clear Adhesive) formed in a sheet shape, and OCR (Optical Clear Resin) which is used by hardening a liquid transparent adhesive.

[0040] As shown in FIG. 5, the front cover substrate 52 has an upper surface and a lower surface opposite the upper surface. The upper surface and the lower surface are spaced apart from each other. The front cover substrate 52 also has a side surface 52c provided between the upper surface and the lower surface. In the example shown in FIGS. 3 and 4, the side surface 52c of the front cover substrate 52 functions as a light incident surface for introducing light into the front cover substrate 52. The front cover substrate 52 functions as a light guide plate. The side surface 52c of the front cover substrate 52 faces the light source unit 30. In this embodiment, when the display panel P1 is viewed in plan, light emitted from the light source unit 30 travels along the Y direction shown in FIG. 4.

[0041] In this embodiment, the front cover substrate 52 is made of glass. In other words, the front cover substrate 52 is a glass substrate made of glass. The front cover substrate 52 is transparent to visible light. Examples of materials for the front cover substrate 52 include glass, as well as organic materials such as acrylic resin or polycarbonate resin.

[0042] As shown in FIG. 5 , the adhesive layer 82 is provided between the lower surface of the front cover substrate 52 and the upper surface of the counter substrate 20. The adhesive layer 82 has an upper surface and a lower surface opposite the upper surface. The upper surface of the adhesive layer 82 is in contact with the lower surface of the front cover substrate 52. The lower surface of the adhesive layer 82 is in contact with the upper surface of the counter substrate 20. The adhesive layer 82 serves to bond the front cover substrate 52 and the counter substrate 20 together. The adhesive layer 82 fixes the front cover substrate 52 to the counter substrate 20. The adhesive layer 82 has visible light transmittance properties. The refractive index of the adhesive layer 82 is preferably closer to the refractive index of the front cover substrate 52 and the counter substrate 20 than that of air. By making the refractive index of the adhesive layer 82 equivalent to that of the front cover substrate 52 and the counter substrate 20, reflection of light L1 at the interfaces between the adhesive layer 82 and the lower surface of the front cover substrate 52 and the upper surface of the counter substrate 20 and the adhesive layer 82 can be suppressed. Examples of adhesive layer 82 include a transparent adhesive sheet called OCA (Optical Clear Adhesive) formed in a sheet shape, and OCR (Optical Clear Resin) which is used by hardening a liquid transparent adhesive. Hereinafter, adhesive layer 81 and adhesive layer 82 may be collectively referred to as adhesive layer 80.

[0043] Next, the effects of the display device 1A according to this embodiment will be described. Transparent displays generally display color images using field sequential driving of three RGB LEDs. As the ambient temperature drops, the rise response speed of the liquid crystal LQ slows. This causes the brightness of the display to begin to decrease. Furthermore, as the ambient temperature drops, the fall response speed of the liquid crystal LQ also slows. This causes the LEDs to continue lighting during the lighting period of the next frame's color. This causes color mixing, and the lower the temperature, the more likely it is that the displayed image will turn monochrome.

[0044] One possible solution to the brightness reduction and monochrome display is to improve the response speed of the liquid crystal LQ. To improve the response speed of the liquid crystal LQ, the liquid crystal LQ must be heated. Raising the temperature using a heater is one possible heating method for improving brightness reduction and monochrome display. However, due to the structure of the display device 1A, the temperature tends to rise on the side closer to the drive circuit 40 and the light source unit 30 due to heat generated by the drive circuit 40 and the light source unit 30, while the temperature tends to fall on the side farther from the drive circuit 40 and the light source unit 30 due to the ambient temperature. In other words, a temperature distribution tends to occur within the surface of the display device 1A. When a heater is used to uniformly heat the surface of the display device 1A in a state where a temperature distribution occurs within the surface, there is a possibility that the temperature of high-temperature areas will rise excessively when low-temperature areas are heated to a predetermined temperature. This may result in increased power consumption.

[0045] In the display device 1A according to this embodiment, the cross-sectional area of ​​the heater wiring HL perpendicular to the longitudinal direction at position R1 is larger than the cross-sectional area of ​​the heater wiring HL perpendicular to the longitudinal direction at position R2. In other words, the resistance of the heater wiring HL at position R1 is smaller than the resistance of the heater wiring HL at position R2. As a result, when the same current flows through the heater wiring HL, the amount of heat generated by the heater wiring HL at position R1 is smaller than the amount of heat generated by the heater wiring HL at position R2. As a result, the amount of heat generated by the heater wiring HL at a position relatively close to the drive circuit 40 and the light source 30 can be reduced. Furthermore, the amount of heat generated by the heater wiring HL at a position relatively far from the drive circuit 40 and the light source 30 can be increased. Therefore, the current value required to increase the temperature can be reduced compared to when the amount of heat generated is uniform across the surface of the heater wiring HL. This reduces the power consumption of the display device 1A. Here, the distance between position R1 and the light source 30 is smaller than the distance between position R2 and the light source 30.

[0046] <Circuit configuration example> Next, an example of the configuration of a circuit included in the display device 1A shown in FIG. 4 will be described. FIG. 6 is a circuit block diagram showing an example of a circuit included in the display device shown in FIG. 4. A wiring path connected to the common electrode CE shown in FIG. 6 is formed, for example, on the opposing substrate 20 shown in FIG. 5. In the example shown in FIG. 6, a light source control unit 32 is included in a drive circuit 40. As a modified example, the light source control unit 32 may be provided separately from the drive circuit 40. The light source control unit 32 is formed, for example, on a wiring board (not shown) connected to the light source unit 30 shown in FIG. 3, and is electrically connected to the light source 31 via the wiring board. The drive circuit 40 is, for example, a driver IC.

[0047] 6, the drive circuit 40 includes a signal processing circuit 41, a pixel control circuit 42, and a display panel drive circuit 47. The display panel drive circuit 47 includes a gate drive circuit 43, a source drive circuit 44, and a common potential drive circuit 45. The light source 31 includes, for example, a red light source section 31r, a green light source section 31g, and a blue light source section 31b. By making the area of ​​the array substrate 10 larger than the area of ​​the counter substrate 20, the drive circuit 40 and the light source section 30 can be provided on the array substrate 10.

[0048] The signal processing circuit 41 includes an input signal analysis unit (input signal analysis circuit) 411, a memory unit (memory circuit) 412, and a signal adjustment unit 413. The display panel P1 has a control unit 90 including a control circuit that controls image display, and an input signal VS is input from the control unit 90 to the input signal analysis unit 411 of the signal processing circuit 41 via a wiring path such as a flexible wiring board (not shown). The input signal analysis unit 411 performs analysis processing based on the input signal VS input from outside, and generates an input signal VCS. The input signal VCS is a signal that determines, for example, what gradation value should be assigned to each pixel PIX (see FIG. 3) of the display panel P1 (see FIG. 3) based on the input signal VS.

[0049] The signal adjustment unit 413 generates an input signal VCSA from the input signal VCS input from the input signal analysis unit 411. The signal adjustment unit 413 sends the input signal VCSA to the pixel control circuit 42 and sends a light source control signal LCSA to the light source control unit 32. The light source control signal LCSA is, for example, a signal including information about the light intensity of the light source 31 that is set according to the input gradation value to the pixel PIX. For example, when a dark image is displayed, the light intensity of the light source 31 is set to be small. When a bright image is displayed, the light intensity of the light source 31 is set to be large.

[0050] The pixel control circuit 42 generates a horizontal drive signal HDS and a vertical drive signal VDS based on the input signal VCSA. For example, in this embodiment, since the field sequential method is used for driving, a horizontal drive signal HDS and a vertical drive signal VDS are generated for each color that the light source 31 can emit. The gate drive circuit 43 sequentially selects gate lines GL of the display panel P1 (see FIG. 3) within one vertical scanning period based on the horizontal drive signal HDS. The order in which the gate lines GL are selected is arbitrary. As shown in FIG. 3, a plurality of gate lines (signal lines) GL extend in the X direction and are arranged along the Y direction.

[0051] Based on the vertical drive signal VDS, the source drive circuit 44 supplies a grayscale signal corresponding to the output grayscale value of each pixel PIX (see FIG. 3) to each source line SL of the display panel P1 (see FIG. 3) within one horizontal scanning period. As shown in FIG. 3, a plurality of source lines (signal lines) SL extend in the Y direction and are arranged along the X direction. One pixel PIX is formed at each intersection of a gate line GL and a source line SL. A switching element Tr is formed at each intersection of the gate line GL and the source line SL. The plurality of gate lines GL and the plurality of source lines SL correspond to a plurality of signal lines that transmit drive signals for driving the liquid crystal LQ.

[0052] The switching element Tr shown in FIG. 6 may be, for example, a thin film transistor. The type of thin film transistor is not particularly limited, and examples include the following: When classified based on the gate position, a bottom-gate transistor or a top-gate transistor can be mentioned. When classified based on the number of gates, a single-gate thin film transistor and a double-gate thin film transistor can be mentioned. One of the source electrode and the drain electrode of the switching element Tr is connected to a source line SL, the gate electrode is connected to a gate line GL, and the other of the source electrode and the drain electrode is connected to one end of a capacitance of a polymer-dispersed liquid crystal LC. One end of the capacitance of the polymer-dispersed liquid crystal LC is connected to the switching element Tr via a pixel electrode PE, and the other end is connected to a common potential line CML via a common electrode CE. A storage capacitance HC is generated between the pixel electrode PE and a storage capacitance electrode electrically connected to the common potential line CML. The common potential line CML is supplied with a voltage from a common potential drive circuit 45.

[0053] <Light source part> The configuration of the light source unit 30 will be described. The light source unit 30 is provided at a position facing the side surface 52c of the front cover substrate 52 (see FIGS. 3 and 4). The light source unit 30 is not particularly limited, but may include, for example, a light source 31 and a lens. The light source 31 includes, for example, a red light source unit 31r, a green light source unit 31g, and a blue light source unit 31b. The red light source unit 31r, the green light source unit 31g, and the blue light source unit 31b are each composed of, for example, a plurality of light-emitting diode elements. The lens is, for example, disposed between the side surface of the front cover substrate 52 shown in FIG. 4 and the plurality of light-emitting diode elements. The plurality of light-emitting diode elements includes a light-emitting diode element capable of emitting light of a first color (e.g., red), a light-emitting diode element capable of emitting light of a second color (e.g., green) different from the first color, and a light-emitting diode element capable of emitting light of a third color (e.g., blue) different from the first color and the second color. The plurality of light-emitting diode elements are arranged in the X direction along the side surface of the front cover substrate 52.

[0054] In the case of the display device 1A that performs color display, for example, the light source control unit 32 controls the turning on and off of the light source 31. Also, the red light source unit 31r, the green light source unit 31g, and the blue light source unit 31b emit light at different timings. Specifically, the light source control unit 32 shown in Fig. 6 outputs a signal SGr that controls the turning on and off of the red light source unit 31r to the red light source unit 31r, a signal SGg that controls the turning on and off of the green light source unit 31g to the green light source unit 31g, and a signal SGb that controls the turning on and off of the blue light source unit 31b to the blue light source unit 31b.

[0055] When adjusting the white balance of the display device 1A, the luminance of the light-emitting diode elements of each color is adjusted based on the chromaticity of each single color of RGB. Specifically, in adjusting the white balance, the current and lighting time input to each of the red light source unit 31r, green light source unit 31g, and blue light source unit 31b are adjusted so as to reduce variations in the luminance of each color of RGB.

[0056] The above describes an example in which the light source unit 30 is provided at a position facing the side surface of the front cover substrate 52. The arrangement of the light source unit 30 is not particularly limited, and the light source unit 30 can be provided at a position facing the side surface of the back cover substrate 51 or at a position facing the side surface of the counter substrate 20.

[0057] <Modification> A modified example of the display device according to the embodiment will be described. Note that the same components will be denoted by the same reference numerals, and the description thereof may be omitted.

[0058] FIG. 7 is a plan view of a display device. In another embodiment, the display device 1B further includes horizontal heater wires XHL arranged in a direction intersecting the heater wires HL. This prevents deterioration of the heater function even if a portion of the heater wires HL and the horizontal heater wires XHL is disconnected. As shown in FIG. 8, two or more horizontal heater wires XHL can be provided. When two or more horizontal heater wires XHL are provided, it is preferable to make the longitudinal cross-sectional area of ​​the horizontal heater wires XHL relatively close to the light source unit 30 larger than the longitudinal cross-sectional area of ​​the horizontal heater wires XHL relatively far from the light source unit 30. This reduces the heat generation amount of the horizontal heater wires XHL located relatively close to the light source unit 30. Furthermore, it increases the heat generation amount of the horizontal heater wires XHL located relatively far from the light source unit 30. As a result, the power consumption of the display device 1C can be further reduced.

[0059] In the example shown in FIG. 5, three source lines SL are provided, and three heater lines HL are provided along each of the source lines SL. On the other hand, in another embodiment, for example, three source lines SL are provided, but only two heater lines HL are arranged. In other words, the number of heater lines HL is made smaller than the number of source lines SL. Furthermore, when the display panel P1 is viewed in plan, it is preferable that the multiple heater lines HL are arranged at equal intervals. This makes the moire less noticeable even if it occurs due to the viewing angle.

[0060] Within the scope of the concept of the present invention, a person skilled in the art may conceive of various modifications and alterations, and it is understood that these modifications and alterations also fall within the scope of the present invention. For example, to the above-described embodiments, a person skilled in the art may appropriately add, delete, or modify components, or add, omit, or change conditions of steps, and these modifications are also included within the scope of the present invention as long as they maintain the gist of the present invention.

[0061] Furthermore, other effects and advantages brought about by the aspects described in this embodiment that are clear from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0062] 1A display device 10 Array board 20 Opposing substrate 30 Light source section 31 Light source 31b Blue light source section 31g green light source section 31r Red light source section 32 Light source control unit 40 Drive circuit 41 Signal processing circuit 42 Pixel control circuit 43 Gate drive circuit 44 Source driver circuit 45 Common potential drive circuit 47 Display panel drive circuit 51 Back cover board 52 Front cover board 60 Planarization layer 70 Orientation film 71 Orientation film 72 Alignment film 80 Adhesive layer 81 Adhesive layer 82 Adhesive layer 90 Control Unit 100 Observer 111 Background 201 Terminal 202 terminal 210 Power supply section 411 Input signal analysis unit 412 Storage section 413 Signal Conditioning Unit BM light shielding material CE common electrode CML common potential wiring DA display area GL gate wiring HC retention capacity HDS horizontal drive signal HL heater wiring L1 light L2 emission light L3 background light LC Polymer dispersed liquid crystal LCSA Light Source Control Signal LQ LCD LQL liquid crystal layer P1 display panel PE pixel electrode PFA surrounding area PIX SGb signal SGg signal SGr signal SL Source wiring Tr switching element VCS input signal VCSA Input Signal VDS Vertical drive signal VS Input signal XHL horizontal heater wiring

Claims

1. a first substrate; a second substrate facing the first substrate; a liquid crystal layer provided between the first substrate and the second substrate; a light source unit provided outside a region where the liquid crystal layer is provided in a plan view; a heater wiring; the heater wire has a first position and a second position; a distance from the first position to the light source unit is shorter than a distance from the second position to the light source unit; a cross-sectional area of ​​the heater wire perpendicular to the longitudinal direction at the first position is larger than a cross-sectional area of ​​the heater wire perpendicular to the longitudinal direction at the second position; Display device.

2. In claim 1, A display device, wherein, in a plan view, a width of the heater wire at the first position is larger than a width of the heater wire at the second position.

3. In claim 1, The heater wiring is a plurality of first heater wires extending in a first direction in a plan view; a second heater wiring provided along a second direction intersecting the first direction in a plan view; The second heater wiring is connected to each of the plurality of first heater wirings.

4. In claim 1, a third substrate provided on the opposite side of the second substrate with respect to the first substrate; The heater wiring is provided on a surface of the third substrate facing the first substrate.

5. In claim 1, a third substrate provided on the opposite side of the second substrate with respect to the first substrate; a fourth substrate provided on the opposite side of the first substrate with respect to the second substrate; Furthermore, The heater wiring is provided on a surface of the third substrate facing the first substrate.

6. In claim 1, The display device further comprises a planarization layer provided so as to cover the heater wiring.

7. In claim 1, a third substrate provided on the opposite side of the second substrate with respect to the first substrate; an adhesive layer provided between the first substrate and the third substrate; The display device further comprises:

8. In claim 1, a light-shielding layer provided on a surface of the second substrate facing the first substrate, A display device, wherein the light-shielding layer is disposed along the heater wiring so as to overlap with the heater wiring in a plan view.

9. In claim 1, the light source unit is provided at a position facing a side surface of the second substrate and is capable of emitting light in a first direction in a plan view; A display device, wherein the heater wiring is provided along the first direction in a plan view.

10. In claim 3, a third heater wiring provided along the second direction intersecting the first direction in a plan view, the third heater wire is connected to each of the plurality of first heater wires; a distance from the second heater wiring to the light source unit is shorter than a distance from the third heater wiring to the light source unit; A display device, wherein a cross-sectional area of ​​the second heater wire perpendicular to the longitudinal direction thereof is larger than a cross-sectional area of ​​the third heater wire perpendicular to the longitudinal direction thereof.

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