Reflective display device

Abstract

A reflective display device includes a display panel, a front light module and a cover plate. The display panel has a display surface. The front light module is arranged above the display surface and is provided with a light-emitting surface and a light turning surface opposite to the light-emitting surface, and the light-emitting surface faces the display surface. The cover plate comprises a body and a plurality of diffusion particles. The body has a first refractive index and has an upper surface and a lower surface, and the lower surface faces the light turning surface. The diffusion particles are distributed in the body and have a second refractive index smaller than the first refractive index.

Description

Technical Field

[0001] The invention relates to a reflective display device, and in particular to a reflective display device with a cover plate containing diffusion particles. Background Art

[0002] Reflective display devices use ambient light or front light sources to provide display light for the display panel. However, since reflective display devices mainly use mirror reflection to reflect display light, the display light emitted from the panel is more concentrated, so compared with transmissive display devices or self-luminous display devices, reflective display devices have a narrower viewing angle. Therefore, how to increase the viewing angle of reflective display devices to meet user needs is one of the goals to be achieved in this technical field. Summary of the invention

[0003] The object of the present invention is to provide a reflective display device which at least has the characteristic of a larger viewing angle.

[0004] The present invention provides a reflective display device, comprising a display panel, a front light module and a cover plate. The display panel has a display surface. The front light module is arranged above the display surface and has a light emitting surface and a light redirecting surface opposite to the light emitting surface, and the light emitting surface faces the display surface. The cover plate comprises a body and a plurality of diffusion particles. The body has a first refractive index, and has an upper surface and a lower surface opposite to the upper surface, and the lower surface faces the light redirecting surface. The diffusion particles are distributed in the body and have a second refractive index less than the first refractive index.

[0005] According to an embodiment of the present invention, each of the plurality of diffusion particles is a sphere.

[0006] According to another embodiment of the present invention, each of the plurality of diffusion particles has a length L in a first direction parallel to the upper surface, and 5 μm≦L≦30 μm.

[0007] According to another embodiment of the present invention, the plurality of diffusion particles have a first arrangement pitch P1 in the first direction, 1.1L≦P1≦1.5L.

[0008] According to another embodiment of the present invention, each of the plurality of diffusion particles has a width W in a second direction parallel to the upper surface and perpendicular to the first direction, and 0.1L≦W≦L.

[0009] According to another embodiment of the present invention, the plurality of diffusion particles have a second arrangement pitch P2 in the second direction, 1.1W≦P2≦1.5W.

[0010] According to another embodiment of the present invention, each of the plurality of diffusion particles has a height H in a third direction perpendicular to the upper surface, and 0.1L≦H≦L.

[0011] According to another embodiment of the present invention, the plurality of diffusion particles have a third arrangement pitch P3 in the third direction, 1.1H≦P3≦1.5H.

[0012] According to yet another embodiment of the present invention, the difference between the first refractive index and the second refractive index is between 0.01 and 0.8.

[0013] According to another embodiment of the present invention, the first refractive index ranges from 1.2 to 1.8, and the second refractive index ranges from 1.0 to 1.6.

[0014] The beneficial effect of the present invention is at least that, through the difference in refractive index between the main body of the cover plate located at the outermost layer of the reflective display device and the diffusion particles, the display light reflected from the display panel and the display surface can be refracted after entering the cover plate so that the light emitted from the cover plate has a wider light output angle range, thereby increasing the proportion of light with a large light output angle, thereby increasing the viewing angle of the reflective display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] For a more complete understanding of the embodiments and their advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0016] Figure 1 is a partial cross-sectional schematic diagram of a reflective display device according to an embodiment of the present invention;

[0017] Figure 2 is a schematic diagram of a cover plate according to an embodiment of the present invention;

[0018] Figure 3 is a schematic diagram of the distribution of diffusion particles in a plane formed by a first direction and a second direction according to an embodiment of the present invention;

[0019] Figure 4 is a schematic diagram of a cover plate according to another embodiment of the present invention;

[0020] Figure 5 FIG. 4 is a schematic diagram of the distribution of diffusion particles in a plane formed by the second direction and the third direction according to another embodiment of the present invention.

[0021]

Explanation of symbols

[0022] 1: Reflective display device

[0023] 10: Display Panel

[0024] 120: array substrate

[0025] 122: first substrate

[0026] 124: Driving element

[0027] 126: Reflective electrode

[0028] 140: Filter substrate

[0029] 142: Second substrate

[0030] 144: Color filter layer

[0031] 146: Black matrix layer

[0032] 160: Liquid crystal layer

[0033] 20: Front light module

[0034] 220: Light source

[0035] 240: Light guide plate

[0036] 242: Light redirection structure

[0037] 30,30A: Cover plate

[0038] 320:Ontology

[0039] 321: Sublayer

[0040] 340:Diffusive particles

[0041] 40: First connection layer

[0042] 420: Optical adhesive

[0043] 440: Polarizer

[0044] 50: Second connection layer

[0045] D1: First direction

[0046] D2: Second direction

[0047] D3: Third direction

[0048] DS: Display Surface

[0049] H: Height

[0050] L: Length

[0051] LS: Lower surface

[0052] P1: first row spacing

[0053] P2: Second row spacing

[0054] P3: The third arrangement spacing

[0055] S1: light emitting surface

[0056] S2: Light redirecting surface

[0057] S3: Light incident surface

[0058] W: Width DETAILED DESCRIPTION

[0059] The following is a detailed discussion of the embodiments of the present invention. However, it is to be understood that the embodiments provide many applicable concepts that can be implemented in a variety of specific contexts. The embodiments discussed and disclosed are for illustration only and are not intended to limit the scope of the present invention.

[0060] In order to clearly present the technical features of the present invention, the dimensions of the components in the drawings will be enlarged in a non-proportional manner, and the number of some components will be reduced. Therefore, the description and explanation of the embodiments of the present invention are not limited to the number of components in the drawings and the dimensions and shapes presented by the components, but should cover the dimensions, shapes and deviations of the two caused by actual processes and / or tolerances. For example, the flat surface shown in the drawings may have rough and / or nonlinear features, and the sharp angles shown in the drawings may be rounded. Therefore, the elements presented in the drawings are mainly for illustration, and are not intended to accurately depict the actual shape of the elements, nor are they intended to limit the scope of protection claimed in the present invention.

[0061] The spatially relative terms used in the present invention, such as "below", "under", "above", "on", etc., are for the purpose of facilitating the description of the relative relationship between one element or feature and another element or feature, as shown in the figure. The true meaning of these spatially relative terms includes other orientations. For example, when the figure is flipped up and down 180 degrees, the relationship between one element and another element may change from "below" or "under" to "above" or "on". In addition, the spatially relative descriptions used in the present invention should also be interpreted in the same way.

[0062] It should be understood that, although the present invention may use the terms "first", "second", "third" and the like to describe various elements or features, these elements or features should not be limited by these terms. These terms are mainly used to distinguish one element from another element, or one feature from another feature. In addition, the term "or" used in the present invention may include any one or more combinations of the associated listed items depending on the actual situation.

[0063] In addition, the present invention may be implemented or applied through other different specific embodiments, and the details of the present invention may also be combined, modified and changed in various embodiments based on different viewpoints and applications without departing from the concept of the present invention.

[0064] Figure 1 1 is a cross-sectional schematic diagram of a reflective display device 1 according to an embodiment of the present invention. The reflective display device 1 comprises a display panel 10, a front light module 20 and a cover plate 30. Figure 1As shown, the display panel 10 has a display surface DS, which is the emission surface of the display light, and the front light module 20 is arranged above the display surface DS. In the present embodiment, the display panel 10 is a fully reflective display panel, but the present invention is not limited thereto. In some embodiments, the display panel 10 may be a semi-penetrating reflective display panel or a micro-penetrating reflective display panel. In addition, in the present embodiment, the display panel 10 is a liquid crystal display panel, but the present invention is not limited thereto. In some embodiments, the display panel 10 may be an electrophoretic display panel or an electrowetting display panel. The front light module 20 has a relative light emitting surface S1 and a light deflecting surface S2, wherein the light emitting surface S1 faces the display surface DS.

[0065] Figure 2 Schematic diagram of the cover plate 30 of the embodiment of the present invention. Figure 1 and Figure 2 The cover plate 30 includes a body 320 and a plurality of diffusion particles 340. The body 320 has an upper surface US and a lower surface LS opposite to each other, wherein the lower surface LS faces the light redirecting surface S2. In detail, the cover plate 30 is a protective cover plate of the reflective display device 1, and the upper surface US of the cover plate 30 is the outermost side of the reflective display device 1.

[0066] The body 320 has a first refractive index, and the diffusion particles 340 are distributed in the body 320 and have a second refractive index that is smaller than the first refractive index. Due to the difference in refractive index between the body 320 and the diffusion particles 340 of the cover plate 30, the display light reflected from the display surface of the display panel 10 can be refracted after entering the cover plate 30, so that the light emitted from the upper surface US of the cover plate 30 has a wider light exit angle range, and the proportion of light with a large light exit angle is increased, thereby increasing the viewing angle of the reflective display device 1.

[0067] In some embodiments, the body 320 has a first refractive index between 1.2 and 1.8 (inclusive). In some embodiments, the diffusion particles 340 have a second refractive index between 1.0 and 1.6 (inclusive). In addition, in some embodiments, the difference between the first refractive index and the second refractive index is between 0.01 and 0.8 (inclusive).

[0068] In some embodiments, the material of the body 320 may be glass, quartz, sapphire, polyester material, polyolefin material, polyimide (PI), polylactic acid (PLA), cycloolefin polymer (COP) or methyl methacrylate-styrene copolymer (MS) resin. The polyester material may be, for example, polyethylene terephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA) or polyethylene naphthalate (PEN), and the polyolefin material may be, for example, polystyrene (PS).

[0069] In some embodiments, the material of the diffusion particles 340 may be air, glass, quartz, polyester material, polyolefin material, polylactic acid, cycloolefin polymer or methyl methacrylate-styrene copolymer resin, wherein the polyester material may be, for example, polyethylene terephthalate, polycarbonate or polymethyl methacrylate, and the polyolefin material may be, for example, polystyrene.

[0070] In some embodiments, the cover plate 30 including the body 320 and the diffusion particles 340 can be formed by precision grinding, sandblasting, embossing or co-extrusion. For example, the embossing process can be used to produce the cover plate 30 including the body 320 and the diffusion particles 340 by hot embossing or ultraviolet embossing using a template. For example, the co-extrusion process can be used to add air or nitrogen (microbubbles) to the molten material of the body 320 in the middle of the screw, and a micro-extension in the machine dimension is generated through vertical flow during extrusion, and the cover plate 30 including the body 320 and the diffusion particles 340 is produced during extrusion; or particles of a material with a higher melting point, such as glass fiber or acrylic cylinder, can be added to the molten material of the body 320, and the cover plate 30 including the body 320 and the diffusion particles 340 is produced during extrusion.

[0071] Please continue to refer to Figure 1, the reflective display device 1 further includes a first connection layer 40 and a second connection layer 50. The first connection layer 40 is located between the display panel 10 and the front light module 20, and is used to connect the display panel 10 and the front light module 20. The second connection layer 50 is located between the front light module 20 and the cover plate 30, and is used to connect the front light module 20 and the cover plate 30. In detail, the first connection layer 40 contacts the display surface DS of the display panel 10 and the light emitting surface S1 of the front light module 20. The second connection layer 50 contacts the light redirecting surface S2 of the front light module 20 and the lower surface LS of the cover plate 30. In some embodiments, as Figure 1 As shown, the first connection layer 40 may include an optical glue 420 and a polarizer 440, wherein one optical glue 420 is used to bond the polarizer 440 to the light guide plate 240, and the other optical glue 420 is used to bond the polarizer 440 to the display panel 10. In some embodiments, the second connection layer 50 may include a frame glue and an air layer (not shown).

[0072] like Figure 1 As shown, the front light module 20 includes a light source 220 and a light guide plate 240. The lower surface and the upper surface of the light guide plate 240 that are opposite to each other are a light emitting surface S1 and a light redirecting surface S2, respectively. The side surface of the light guide plate 240 includes a light incident surface S3, and the light source 220 is disposed on the light incident surface S3. In some embodiments, there is a gap between the light source 220 and the light incident surface S3. In some embodiments, a glue layer is disposed between the light source 220 and the light incident surface S3 to connect the light source 220 and the light incident surface S3.

[0073] In some embodiments, the light source 220 may include a light emitting diode. In some embodiments, the light redirecting surface S2 may include a light redirecting structure 242. In addition, in some embodiments, the material of the light redirecting structure 242 may be air, a polyester material (such as polyethylene terephthalate, polycarbonate, etc.) or polymethyl methacrylate.

[0074] Please continue to refer to Figure 1 The display panel 10 includes an array substrate 120, a filter substrate 140, and a liquid crystal layer 160 located between the array substrate 120 and the filter substrate 140. The array substrate 120 includes a first substrate 122, and a driving element 124 and a reflective electrode 126 located on the first substrate 122. The filter substrate 140 includes a second substrate 142, and a color filter layer 144 and a black matrix layer 146 located on the second substrate 142.

[0075] In some embodiments, the materials of the first substrate 122 and the second substrate 142 may be glass or a transparent polymer material. The aforementioned transparent polymer material may be, for example, polyethylene terephthalate or polyimide. The driving element 124 may include elements or circuits of the reflective display device 1, such as a switch element, a storage capacitor, and a signal line. The material of the reflective electrode 126 may be a metal material with high reflectivity, such as aluminum or silver. For example, the driving element 124 and the reflective electrode 126 may be formed by a thin film deposition process, a lithography process, and an etching process.

[0076] In some embodiments, the color filter layer 144 may be a color photoresist that allows light of a specific color to pass through. For example, the color filter layer 144 may include red, green, and blue photoresists. The black matrix layer 146 may be a black photoresist or a black ink. The color filter layer 144 and the black matrix layer 146 may be formed by coating, inkjet, printing, lithography, or etching.

[0077] Please refer to Figure 2 , the diffusion particles 340 are dispersed in the body 320. In some embodiments, the distribution of the diffusion particles 340 in the body 320 may be regular distribution, such as array distribution. In some embodiments, the distribution of the diffusion particles 340 in the body 320 may be irregular distribution, such as random distribution. In some embodiments, the diffusion particles 340 may be spheres, such as ellipsoids or spheres.

[0078] like Figure 2 As shown, the first direction D1, the second direction D2 and the third direction D3 are perpendicular to each other in the three-dimensional space. For example, the first direction D1, the second direction D2 and the third direction D3 can be the Y-axis, X-axis and Z-axis directions of the three-dimensional coordinate system, respectively. In some embodiments, in a plane parallel to the upper surface US of the body 320 and formed by the first direction D1 and the second direction D2, the projection of the ellipsoidal diffusion particle 340 is an ellipse, whose major axis is parallel to the first direction D1 and whose minor axis is parallel to the second direction D2. In a plane perpendicular to the upper surface US and formed by the second direction D2 and the third direction D3, the projection of the ellipsoidal diffusion particle 340 is a circle.

[0079] Figure 3 FIG. 3 is a schematic diagram showing the distribution of the diffusion particles 340 in the plane formed by the first direction D1 and the second direction D2 according to an embodiment of the present invention. Figure 3As shown, the diffusion particles 340 have a length L between 5 μm and 30 μm (5 μm≦L≦30 μm) in a first direction D1 parallel to the upper surface US of the body 320. The diffusion particles 340 have a width W between 0.1L and L (0.1L≦W≦L) in a second direction D2 parallel to the upper surface US of the body 320. In some embodiments, the lengths L of the diffusion particles 340 are substantially equal. In other embodiments, the lengths L of the diffusion particles 340 may be substantially unequal. In addition, in some embodiments, the widths W of the diffusion particles 340 are substantially equal. In other embodiments, the widths W of the diffusion particles 340 may also be substantially unequal.

[0080] Please continue to refer to Figure 3 , the diffusion particles 340 have a first arrangement pitch P1 between 1.1L and 1.5L in the first direction D1 (1.1L≦P1≦1.5L), and have a second arrangement pitch P2 between 1.1W and 1.5W in the second direction D2 (1.1W≦P2≦1.5W). In each embodiment, according to the product design requirements of the reflective display device 1, the first arrangement pitch P1 of the diffusion particles 340 can be substantially equal or substantially unequal, and / or the second arrangement pitch P2 of the diffusion particles 340 can be substantially equal or substantially unequal.

[0081] By designing the length L, width W, first arrangement spacing P1 and second arrangement spacing P2 of the above-mentioned diffusion particles 340, the proportion of light with a large light output angle can be increased, thereby increasing the viewing angle of the reflective display device 1 (for example, the viewing angle can be increased by 40 degrees to 70 degrees compared to a reflective display device that does not contain the cover plate 30 of the present invention), especially for medium and large-sized reflective display devices such as those with a size of 10 inches or more.

[0082] Take two different sizes and arrangement spacing designs of diffusion particles 340 as an example. The length L, width W, first arrangement spacing P1 and second arrangement spacing P2 of one are 10μm, L, 1.1L and 1.1W respectively, while the length L, width W, first arrangement spacing P1 and second arrangement spacing P2 of the other are 10μm, 0.1L, 1.5L and 1.5W respectively. Both can increase the proportion of light with a large light output angle and increase the viewing angle, and the viewing angle of the former will be greater than that of the latter. Therefore, by adjusting the design of the length L, width W, first arrangement spacing P1 and second arrangement spacing P2 of the above-mentioned diffusion particles 340, product requirements of different viewing angles can be met.

[0083] Figure 4 is a schematic diagram of a cover plate 30A according to another embodiment of the present invention. Figure 4 Examples and Figure 2Most of the component structures, materials, processes and relative positional relationships of the embodiments of the present invention are the same, so they will not be repeated here. The only difference between them is that the body 320 of the cover plate 30A includes a plurality of sub-layers 321 stacked along the third direction D3 and a plurality of diffusion particles 340 distributed in the plurality of sub-layers 321. In some embodiments, the distribution of the diffusion particles 340 in the plurality of sub-layers 321 can be a regular distribution, such as an array distribution. In some embodiments, the distribution of the diffusion particles 340 in the plurality of sub-layers 321 can be an irregular distribution, such as a random distribution. In some embodiments, the distribution of the diffusion particles 340 in each sub-layer 321 can be substantially the same or different.

[0084] The cover plate 30A formed by stacking a plurality of sub-layers 321 in which the diffusion particles 340 are distributed can be applied to a large-sized reflective display device, for example, larger than 20 inches. Since a large-sized reflective display device has a large light emitting area, the number of the diffusion particles 340 can be increased by stacking a plurality of sub-layers 321 in which the diffusion particles 340 are distributed, thereby effectively increasing the proportion of light with a large light emitting angle, thereby increasing the viewing angle of the large-sized reflective display device.

[0085] Figure 5 FIG. 3 is a schematic diagram showing the distribution of diffusion particles 340 in a plane formed by the second direction D2 and the third direction D3 according to another embodiment of the present invention. Figure 5 As shown, the diffusion particles 340 have a height H between 0.1L and L (0.1L≦H≦L) in the third direction D3 perpendicular to the upper surface US of the body 320. The diffusion particles 340 have a third arrangement pitch P3 between 1.1H and 1.5H (1.1H≦P3≦1.5H) in the third direction D3. In each embodiment, according to the product design requirements of the reflective display device 1, the height H of the diffusion particles 340 can be substantially equal or substantially unequal, and / or the third arrangement pitch P3 of the diffusion particles 340 can be substantially equal or substantially unequal.

[0086] In summary, the present invention utilizes the difference in refractive index between the main body of the cover plate located at the outermost layer of the reflective display device and the diffusion particles, so that the display light reflected from the display panel and the display surface enters the cover plate and is refracted so that the light emitted from the cover plate has a wider light output angle range, thereby increasing the proportion of light with a large light output angle, and thereby increasing the viewing angle of the reflective display device.

[0087] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. A person having ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the attached claims.

Claims

1. A reflective display device, characterized in that: include: A display panel having a display surface; a front light module, disposed above the display surface of the display panel, the front light module having a light emitting surface and a light redirecting surface opposite to the light emitting surface, the light emitting surface facing the display surface; as well as A cover plate, disposed above the light redirecting surface of the front light module, the cover plate comprising: A body having an upper surface and a lower surface opposite to the upper surface, wherein the lower surface faces the light redirecting surface, and the body has a first refractive index; as well as A plurality of diffusion particles are distributed in the body and have a second refractive index, wherein the second refractive index is smaller than the first refractive index.

2. The reflective display device according to claim 1, wherein: Each of the plurality of diffusion particles is a sphere.

3. The reflective display device according to claim 2, wherein: Each of the plurality of diffusion particles has a length L in a first direction parallel to the upper surface, and 5 μm≦L≦30 μm.

4. The reflective display device according to claim 3, wherein: The plurality of diffusion particles have a first arrangement pitch P1 in the first direction, 1.1L≦P1≦1.5L.

5. The reflective display device according to claim 3, wherein: Each of the plurality of diffusion particles has a width W in a second direction parallel to the upper surface and perpendicular to the first direction, and 0.1L≦W≦L.

6. The reflective display device according to claim 5, wherein: The plurality of diffusion particles have a second arrangement pitch P2 in the second direction, 1.1W≦P2≦1.5W.

7. The reflective display device according to claim 3, wherein: Each of the plurality of diffusion particles has a height H in a third direction perpendicular to the upper surface, and 0.1L≦H≦L.

8. The reflective display device according to claim 7, wherein: The plurality of diffusion particles have a third arrangement pitch P3 in the third direction, 1.1H≦P3≦1.5H.

9. The reflective display device according to claim 1, wherein: The difference between the first refractive index and the second refractive index is between 0.01 and 0.

8.

10. The reflective display device according to claim 1, wherein: The first refractive index ranges from 1.2 to 1.8, and the second refractive index ranges from 1.0 to 1.6.

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