Display device

Abstract

The purpose of the present invention is to provide a display device with which gradation images can be visually recognized without discomfort.　This display device (1) comprises: a display unit (2) that can assume a gradation image display state and a gradation image non-display state; a decorative layer (4) that is disposed facing the display unit (2) and is provided with an optically transparent decoration (40); and a surface light-emitting unit (3) that is disposed between the display unit (2) and the decorative layer (4), has a function for irradiating the decorative layer (4) with light (L2), and has optical transparency sufficient to transmit a gradation image (TI). In the gradation image display state, a gradation image (TI2) is visible from the decorative-layer (4) side via the surface light-emitting unit (3), and, at the same time, is irradiated with the light (L2) directed from the surface light-emitting unit (3) toward the decorative layer (4). The light (L2) is transmitted through the decoration (40), thereby suppressing the effect of the decoration of hindering the visibility of the gradation image (TI2). In the gradation image non-display state, the emission of the light (L2) directed from the surface light-emitting unit (3) toward the decorative layer (4) is stopped, whereby the decoration (40) can be visually recognized.

Description

display device

[0001] This technology relates to a display device.

[0002] Display devices for displaying images have been known for some time. The display device with a panel described in Patent Document 1 (Japanese Patent No. 7307899) comprises a display device with a decorative sheet and a panel member. The display device with a decorative sheet has a display surface for displaying images and a decorative sheet provided opposite the display surface. When no image is displayed on the display device, the pattern on the decorative sheet can be viewed. When an image is displayed on the display device, the image can be viewed through the decorative sheet.

[0003] Patent No. 7307899

[0004] However, if the image is a color or monochrome image that includes relatively low-luminance areas (for example, black areas), the pattern of the decorative sheet will be superimposed directly onto those low-luminance areas, which may result in an unnatural appearance depending on the image.

[0005] This technology aims to provide a display device that allows users to view grayscale images without any unnatural appearance.

[0006] The display device of this technology comprises a display unit having a display area that can take on a grayscale image display state in which a grayscale image is displayed and a grayscale image non-display state in which the grayscale image is not displayed; a decorative layer disposed opposite the display area and having a light-transmitting decoration; and a surface light-emitting unit disposed between the display area and the decorative layer and having a surface light-emitting function that irradiates light onto the decorative layer and light transmittance that allows the grayscale image to pass through. In the grayscale image display state, the grayscale image is visible from the decorative layer side through the surface light-emitting unit, and at the same time, light is irradiated toward the decorative layer by the surface light-emitting function, and by passing through the decoration, the effect of the decoration that hinders the visibility of the grayscale image is suppressed. In the grayscale image non-display state, the irradiation of light toward the decorative layer by the surface light-emitting function is stopped, making the decoration visible.

[0007] This technology makes it possible to view grayscale images without any unnaturalness.

[0008] This is an exploded perspective view of the display device according to the first embodiment. This is a diagram showing an example of the configuration of the decorative layer. This is a diagram showing an example of the configuration of the decorative layer. This is a diagram showing an example of the configuration of the decorative layer. This is a diagram showing an example of the configuration of the decorative layer. This is a diagram showing the viewing state for the display device. This is a diagram showing the viewing state for the display device. This is a diagram showing the viewing state for the display device. This is a side view of the display device according to the second embodiment. This is a side view of the display device according to the third embodiment. This is a diagram showing an example of the application of the display device.

[0009] The following describes each embodiment in detail with reference to the drawings. However, the configurations described in the following embodiments are merely examples, and the scope of this technology is not limited by the configurations described in each embodiment. For example, each part constituting this technology can be replaced with any configuration that can perform a similar function. In addition, any configuration may be added. Furthermore, any two or more configurations (features) from each embodiment can be combined.

[0010] <First Embodiment> The first embodiment will be described below with reference to Figures 1 to 3. Figure 1 is an exploded perspective view of the display device according to the first embodiment. Figures 2 and 3 are diagrams showing examples of the configuration of the decorative layer, respectively. Figure 2A is a plan view of the decorative layer. Figure 2B is a cross-sectional view taken along line A-A in Figure 2A. Figure 3A is a plan view of the dots constituting the decoration. Figure 3B is a cross-sectional view taken along line B-B in Figure 3A. For the sake of explanation, the upper side in Figures 1, 2A, and 3A will be referred to as "upper (or above)," and the lower side will be referred to as "lower (or below)."

[0011] As shown in Figure 1, the display device 1 comprises a display unit 2, a surface light-emitting unit 3, and a decorative layer 4, which are stacked in order from bottom to top. The display unit 2 has a display area 21 on which an image can be viewed. In this embodiment, the image displayed in the display area 21 is a color gradation image TI that includes areas with relatively low brightness (for example, black areas). In the example shown in Figure 1, the gradation image TI is an image that includes a panda P. The gradation image TI may be a moving image or a still image. Furthermore, the display unit 2 is not particularly limited, and for example, a liquid crystal display or an organic EL display can be used. As a result, the display unit 2 can display the gradation image TI using each color component of RGB.

[0012] The display area 21 can take on two states. The first state is the grayscale image display state (hereinafter referred to as the "image display state"), in which the grayscale image TI is displayed. The second state is the grayscale image non-display state (hereinafter referred to as the "image non-display state"), in which the grayscale image TI is not emitted toward the decorative layer 4 (no light is shone toward it), and the display area 21 appears completely black.

[0013] A decorative layer 4 is positioned above the display area 21, facing the display area 21. The decorative layer 4 is large enough to encompass the entire display area 21 when the display device 1 is viewed from above (in a plan view). The decorative layer 4 is a sheet-like member with a light-transmitting decoration 40 applied to it. In this case, the total light transmittance of the decorative layer 4 is preferably 50% or more, and more preferably 60% to 80%. This allows the light L2 irradiated from the surface light-emitting part 3 onto the decorative layer 4 to be transmitted through the decorative layer 4 (decoration 40), thus contributing to energy saving. In this embodiment, the decoration 40 is a wood grain pattern, but is not limited to this. For example, it may be black or other single-color paint, metallic or stone patterns, checkered patterns, tortoiseshell patterns, etc. Furthermore, the surface may be treated with decorative processing such as high gloss, matte, or other functional processing such as anti-reflective or scratch-resistant, or combinations thereof.

[0014] As a means for applying a decoration 40 having light transmissivity to the decorative layer 4, for example, a method of forming fine openings in a decoration having no light transmissivity to impart light transmissivity, as described in Japanese Patent No. 7365576, or a method of forming a decoration having light transmissivity using a pigment that develops color as interference light on the reflection light side, as described in Japanese Patent No. 5725581, can be mentioned. In the method described in Japanese Patent No. 7365576, if an attempt is made to increase the total light transmittance of the decorative layer 4, the area of the openings becomes large, and as a result, there is a possibility that the decoration 40 cannot be clearly visually recognized. Therefore, the method described in Japanese Patent No. 5725581 is more preferable. The method described in Japanese Patent No. 5725581 is specifically shown below.

[0015] As shown in FIGS. 2A and 2B, the decorative layer 4 has a base film 41 and a pattern layer 42 provided on the base film 41 and constituting the decoration 40. The pattern layer 42 has a first color pattern layer composed of a plurality of first color dots 423 having red (the first color dots 423 ｉ－２ , the first color dots 423 ｉ－１ , the first color dots 423 ｉ , the first color dots 423 ｉ＋１ , the first color dots 423 ｉ＋２ , the first color dots 423 ｉ＋３ ). Further, the pattern layer 42 has a second color pattern layer provided on the first color pattern layer and composed of a plurality of second color dots 422 having green (the second color dots 422 ｉ－１ , the second color dots 422 ｉ , the second color dots 422 ｉ＋１ ). Furthermore, the pattern layer 42 has a third color pattern layer provided on the second color pattern layer and composed of a plurality of third color dots 421 having blue (the third color dots 421 ｉ－１ , the third color dots 421 ｉ ). The first color dots 423, the second color dots 422, and the third color dots 421 are dots that become "halftone dots" of screen printing, respectively.

[0016] As shown in Figures 3A and 3B, the first color dot 423 includes a first color binder 4232 and first color pigment chips 4231a, 4231b, 4231c, and 4231d dispersed within the first color binder 4232. Each of the first color pigment chips 4231a to 4231d has a thin flake that is transparent to light in the visible light region and a metal oxide film covering the flake. The material of the flake is not particularly limited, and for example, natural mica, synthetic mica, silica, alumina, glass, polysilicate, etc. can be used. Similar to the first color dot 423, the second color dot 422 includes a second color binder and a plurality of second color pigment chips dispersed within the second color binder. Furthermore, the third color dot 421 includes a third color binder and a plurality of third color pigment chips dispersed within the third color binder.

[0017] Thus, the pattern layer 42 contains at least three types of pigment chips. The first pigment chip is a red interference pigment that produces color as interference light on the reflected light side. The second pigment chip is a green interference pigment that produces color as interference light on the reflected light side. The third pigment chip is a blue interference pigment that produces color as interference light on the reflected light side. By containing the red, green, and blue interference pigments, the pattern layer 42 can perform additive color mixing of interference light.

[0018] As shown in Figure 1, a surface light-emitting unit 3 is positioned between the display area 21 of the display unit 2 and the decorative layer 4. The surface light-emitting unit 3 is configured to irradiate the decorative layer 4 with light L2, which will be described later, using an edge-lighting method. Specifically, the surface light-emitting unit 3 has a light guide plate 31 positioned opposite the display area 21 and a light source 32 positioned on the side 311 of the light guide plate 31. The light guide plate 31, like the decorative layer 4, is sized to encompass the entire display area 21 when the display device 1 is viewed from above. The surface light-emitting unit 3 may be, for example, a self-emissive material such as an organic EL.

[0019] The light source 32 irradiates light L1 toward the side surface 311 of the light guide plate 31. This allows light L1 to be irradiated from a direction that does not interfere with the display area 21. Light L1 from the light source 32 is also incident on the light guide plate 31. This light L1 then exits as light L2 from the upper surface 312 of the light guide plate 31. In the display device 1, the light L2 exiting from the upper surface 312 contributes to the operation in the image display state, as will be described later. The light L2 exiting from the upper surface 312 is directed toward the decorative layer 4. In this way, the light guide plate 31 (surface light emitting part 3) has a surface light emitting function that irradiates light L2 onto the decorative layer 4. The light source 32 is not particularly limited, and for example, an LED can be used. The emission spectrum only needs to include a part or all of the visible light wavelength range, and is preferably, for example, 360 nm to 830 nm. The constituent material of the light guide plate 31 is not particularly limited, and for example, an acrylic resin can be used. Furthermore, as mentioned above, the light L2 may be emitted not only from the upper surface 312, but also from the lower surface 313 of the light guide plate 31.

[0020] Furthermore, the light guide plate 31 has light transmittance that allows the grayscale image TI to pass through. Hereinafter, the grayscale image TI that has passed through the light guide plate 31 will be referred to as "grayscale image TI1". The total light transmittance in the thickness direction of the light guide plate 31 is preferably 80% or more, and more preferably 90% or more and 99% or less. In addition, the decorative layer 4, due to its light transmittance, transmits the light L2 irradiated by the surface light emission function and the grayscale image TI1. Hereinafter, the composite component of the light L2 that has passed through the decorative layer 4 and the grayscale image TI1 will be referred to as "grayscale image TI2". Due to this light transmittance, a decrease in the visibility of the grayscale image TI2 in the image display state can be prevented. Furthermore, it is preferable that the average illumination light intensity of the grayscale image TI emitted from the display area 21 of the display unit to the light guide plate 31 is higher than the illumination light intensity of the light L2 directed toward the decorative layer 4 by the surface light emission function, that is, the light L2 emitted from the upper surface 312 of the light guide plate 31 to the decorative layer 4. This makes it possible to increase the contrast ratio of the grayscale image TI2 that is visible after passing through the decorative layer 4. The contrast ratio of the grayscale image TI2 is preferably 1:100 to 1:5000.

[0021] Next, the image display state and the image non-display state will be described. Figure 4 is a diagram showing the viewing state of the display device. Figure 4A is a plan view showing the image display state of the display device of this embodiment. Figure 4B is a plan view showing the image display state of the display device of the comparative example. Figure 4C is a plan view showing the image non-display state of the display device of this embodiment. Note that the display device 1' of the comparative example has the same configuration as the display device 1 except that the surface light-emitting section 3 is omitted.

[0022] As shown in Figure 4A, in the image display state of the display device 1, the grayscale image TI is visible as grayscale image TI2 from the decorative layer 4 side. At that time, light L2 is irradiated toward the decorative layer 4 by the surface light emission function. This light L2 passes through the decoration 40 of the decorative layer 4. Due to this transmission, the decoration 40 cannot be seen (visually inspected), that is, the decoration 40 can be made to disappear visually. As a result, the influence of the decoration 40 that hinders the visibility of the grayscale image TI2 can be suppressed, and therefore, the panda P included in the grayscale image TI2 can be seen in its natural colors, that is, in its black and white body color. Also, as mentioned above, the decorative layer 4 and the light guide plate 31 are large enough to encompass the entire display area 21 when the display device 1 is viewed from above. As a result, even if the panda P moves to the right side in Figure 4A, for example, the panda P can be seen in its natural colors without being affected by the decoration 40.

[0023] As shown in Figure 4B, in the image display state of the display device 1', the grayscale image TI is visible as the grayscale image TI2' from the decorative layer 4 side. As mentioned above, the display device 1' has a configuration in which the surface light-emitting section 3 is omitted. Therefore, the parts of the panda P with relatively low brightness (for example, parts with a black body color) are visible as the decoration 40 is superimposed on them. In this case, the panda P may appear unnatural (unnatural) to the viewer. In contrast, in the image display state of the display device 1, the grayscale image TI2 (especially the panda P) can be viewed without any sense of unnaturalness.

[0024] As shown in Figure 4C, when the display device 1 is in the image-display state, the irradiation of light L2 toward the decorative layer 4 by the surface-emitting function of the surface-emitting unit 3 is stopped. As a result, the decorative layer 4 does not transmit light L2 and the grayscale image TI1, and the decoration 40 is visible on the decorative layer 4. In the image-display state of the display device 1', the decoration 40 is visible in the same way as in the image-display state of the display device 1.

[0025] <Second Embodiment> The second embodiment will be described below with reference to Figure 5, focusing on the differences from the previously described embodiment, and similar matters will be omitted from the explanation. Figure 5 is a side view of the display device according to the second embodiment. For the sake of explanation, the upper side in Figure 5 will be referred to as "upper (or upward)" and the lower side as "lower (or downward)". As shown in Figure 5, in this embodiment, of the display unit 2, the light guide plate 31, and the decorative layer 4, the size of the display unit 2 and the decorative layer 4 in a plan view is the same, while the light guide plate 31 is larger than the display unit 2 and the decorative layer 4. As a result, the light guide plate 31 has a protruding portion 314 that protrudes beyond the display unit 2 and the decorative layer 4. Light L1 is irradiated from the side 311, upper surface 312, and lower surface 313 included in the protruding portion 314. As a result, light L1 can be incident on the light guide plate 31 from a direction that does not interfere with the display area 21. Furthermore, the light L2 directed from the light guide plate 31 toward the decorative layer 4 emits light uniformly without any unevenness in intensity in the display area 21.

[0026] <Third Embodiment> The third embodiment will now be described with reference to Figure 6, focusing on the differences from the previously described embodiments, and similar matters will be omitted from the explanation. Figure 6 is a side view of the display device according to the third embodiment. For the sake of explanation, the upper side in Figure 6 will be referred to as "upper (or upward)" and the lower side as "lower (or downward)". As shown in Figure 6, in this embodiment, of the display unit 2, the light guide plate 31, and the decorative layer 4, the display unit 2 is the smallest in plan view, the decorative layer 4 is the largest, and the light guide plate 31 is of an intermediate size between the display unit 2 and the decorative layer 4. As a result, the light guide plate 31 has a protruding portion 315 that protrudes more than the display unit 2. Light L1 is irradiated from the side surface 311 and the bottom surface 313 included in the protruding portion 315. As a result, light L1 can be incident on the light guide plate 31 from a direction that does not interfere with the display area 21. Furthermore, the light L2 directed from the light guide plate 31 toward the decorative layer 4 emits light uniformly without any unevenness in intensity in the display area 21.

[0027] <Application Examples> The following describes application examples of the display devices of the first to third embodiments with reference to Figure 7. Figure 7 is a diagram showing application examples of the display device. For the sake of explanation, the upper side of Figure 7 will be referred to as "upper (or upward)" and the lower side as "lower (or downward)". As shown in Figure 7, the display device 1 is a display device for automobiles (in-vehicle use). Here, as an example, the display device 1 has the function of an instrument that displays speed and the function of displaying a map of a car navigation system. In this way, one display device 1 can have multiple functions. The decorative layer 4 constitutes the outermost layer of the center cluster of the automobile. In addition, the display device 1 can be used not only in automobiles, but also in small saddle-type vehicles such as motorcycles, as well as in railways, ships, aircraft, etc.

[0028] Although preferred embodiments of this technology have been described above, this technology is not limited to the embodiments described above, and various modifications and changes are possible within the scope of its gist.

[0029] This application claims priority based on Japanese Patent Application No. 2024-205582, filed on 26 November 2024, and all of its contents are incorporated herein by reference.

[0030] 1 Display device 2 Display unit 21 Display area 3 Surface light-emitting unit 31 Light guide plate 4 Decorative layer 40 Decoration TI, TI1, TI2 Tone image

Claims

1. A display device comprising: a display unit having a display area capable of taking between a grayscale image display state in which a grayscale image is displayed and a grayscale image non-display state in which the grayscale image is not displayed; a decorative layer disposed opposite the display area and having a light-transmitting decoration; and a surface light-emitting unit disposed between the display area and the decorative layer and having a surface light-emitting function for irradiating light onto the decorative layer and light transmittance that allows the grayscale image to pass through, wherein in the grayscale image display state, the grayscale image is visible from the decorative layer side through the surface light-emitting unit, and at the same time, light is irradiated toward the decorative layer by the surface light-emitting function, and the light passes through the decoration, thereby suppressing the influence of the decoration that would hinder the visibility of the grayscale image; and in the grayscale image non-display state, the irradiation of light toward the decorative layer by the surface light-emitting function is stopped, making the decoration visible.

2. The display device according to claim 1, wherein the average illumination light intensity of the grayscale image is higher than the illumination light intensity of the light directed toward the decorative layer by the surface light emission function.

3. The display device according to claim 2, wherein the surface light-emitting unit includes a light guide plate that directs the light toward the decorative layer when light is irradiated onto the decorative layer by the surface light-emitting function, and a light source that irradiates the light guide plate with light from a direction that does not interfere with the display area, and the light guide plate is such that light from the light source is incident on it and the light is emitted onto the decorative layer.

4. The display device according to claim 1, 2, or 3, wherein the decorative layer is composed of a sheet-like member with a total light transmittance of 50% or more.

5. The display device according to claim 4, wherein the decorative layer comprises a base film and a pattern layer provided on the base film and constituting the decoration, the pattern layer includes at least three types of pigment chips, each of the three types of pigment chips being one of a red interference pigment, a green interference pigment, and a blue interference pigment that produces color as interference light on the reflected light side, and the interference light is additively mixed.

6. The display device according to claim 5, which is an in-vehicle display device.

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