Light guide plate and display device

Abstract

The invention discloses a light guide plate and a display device. The display device comprises a reflective display panel, the light guide plate, a light source and a first optical adhesive layer. The light guide plate is located above the reflective display panel. The light guide plate has an upper surface, a lower surface and a light incident surface connecting the upper and lower surfaces. The light guide plate further comprises a plurality of microstructures located on the upper surface and a plurality of columnar structures located on the lower surface. The light source faces the light incident surface of the light guide plate. The first optical adhesive layer is located on the lower surface of the light guide plate and makes contact with the columnar structure, and the refractive index of the first optical adhesive layer is lower than that of the light guide plate. According to the invention, through the asymmetric microstructure on the upper surface of the light guide plate and the columnar structure on the lower surface of the light guide plate, the incident light enters the reflective display panel approximately vertically, and the consistency of the advancing direction of the reflected light is reduced at the same time. The first optical adhesive layer and the second optical adhesive layer which are low in refractive index are in contact with the lower surface and the upper surface to form an interface with refractive index difference, so that the color saturation of the display device is increased, and the quality of a display picture is improved.

Description

Technical Field

[0001] The present disclosure relates to a display device. Background Art

[0002] In a display device equipped with a reflective display panel, a microstructure can be formed on the upper surface of the light guide plate to increase the light guide effect and improve the color saturation of the display device. However, such a design will cause the reflected light generated when the light passes through the interface of the multi-layer material to produce a stripe pattern in the dark display screen, resulting in defects in display quality.

[0003] In view of this, how to provide a display device that can solve the above problems is still a goal of research and development in the field. Summary of the invention

[0004] A technical aspect of the present disclosure is a display device.

[0005] In one embodiment of the present disclosure, a display device includes a reflective display panel, a light guide plate, a light source, and a first optical adhesive layer. The light guide plate is located above the reflective display panel. The light guide plate has an upper surface, a lower surface, and a light incident surface connecting the upper surface and the lower surface. The light guide plate also includes a plurality of microstructures located on the upper surface and a plurality of columnar structures located on the lower surface. The light source faces the light incident surface of the light guide plate. The first optical adhesive layer is located on the lower surface of the light guide plate and contacts the columnar structures, wherein the refractive index of the first optical adhesive layer is lower than the refractive index of the light guide plate.

[0006] In one embodiment of the present disclosure, the outline of the columnar structure includes a semi-circular column, a triangular column, or a semi-elliptical column.

[0007] In one embodiment of the present disclosure, there is no gap between two adjacent columnar structures.

[0008] In one embodiment of the present disclosure, the microstructure is asymmetric.

[0009] In one embodiment of the present disclosure, the light incident surface has a normal direction, the columnar structures are arranged in a first direction and extend in a second direction, the first direction is perpendicular to the normal direction, and the normal direction is parallel to the second direction.

[0010] In one embodiment of the present disclosure, the columnar structure has a central angle in the range of 30 degrees to 50 degrees.

[0011] In one embodiment of the present disclosure, each of the columnar structures has a width and a depth, and an aspect ratio of the depth divided by the width is in a range of 0.08 to 0.5.

[0012] In one embodiment of the present disclosure, the columnar structure protrudes from the lower surface of the light guide plate toward the reflective display panel, and the columnar structure and the light guide plate are integrally formed.

[0013] In one embodiment of the present disclosure, the microstructure is recessed from the upper surface toward the lower surface of the light guide plate.

[0014] In one embodiment of the present disclosure, the microstructure has a first surface close to the light incident surface, and a first angle is formed between the first surface and the upper surface of the light guide plate, and the first angle is in a range of 20 degrees to 40 degrees.

[0015] In one embodiment of the present disclosure, the microstructure has a second surface away from the light incident surface, and a second angle is formed between the second surface and the upper surface of the light guide plate, and the second angle is in a range of 60 degrees to 89 degrees.

[0016] In one embodiment of the present disclosure, the display device further includes a second optical adhesive layer located on the lower surface of the light guide plate and contacting the columnar structure. The refractive index of the second optical adhesive layer is lower than the refractive index of the light guide plate.

[0017] A technical aspect of the present disclosure is a light guide plate for a reflective display device, which includes a reflective display panel, a light source facing the light guide plate, and an optical adhesive layer contacting a lower surface of the light guide plate.

[0018] In one embodiment of the present disclosure, the light guide plate has a plurality of microstructures on the upper surface and a plurality of columnar structures on the lower surface, and the columnar structures are arranged in a first direction.

[0019] In one embodiment of the present disclosure, the microstructure is asymmetric.

[0020] In one embodiment of the present disclosure, there is no gap between two adjacent columnar structures.

[0021] In one embodiment of the present disclosure, the columnar structure has a central angle in the range of 30 degrees to 50 degrees.

[0022] In one embodiment of the present disclosure, each of the columnar structures has a width and a depth, and an aspect ratio of the depth divided by the width is in a range of 0.08 to 0.5.

[0023] In one embodiment of the present disclosure, the columnar structure protrudes from the lower surface of the light guide plate toward the reflective display panel, and the columnar structure and the light guide plate are integrally formed.

[0024] In one embodiment of the present disclosure, the microstructure is recessed from the upper surface toward the lower surface of the light guide plate.

[0025] In the above embodiment, the present disclosure uses the asymmetric microstructure on the upper surface of the light guide plate and the columnar structure on the lower surface of the light guide plate to make the incident light enter the reflective display panel nearly vertically, while reducing the consistency of the traveling direction of the reflected light. The first optical adhesive layer with a low refractive index and the second optical adhesive layer contact the lower surface and the upper surface to form an interface with a refractive index difference, thereby increasing the color saturation of the display device and improving the quality of the display image. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1A is a side view of a display device according to an embodiment of the present disclosure;

[0027] Figure 1B for Figure 1A A partial stereoscopic diagram of a display device in FIG.

[0028] Figure 2A is a side view of a display device according to another embodiment of the present disclosure;

[0029] Figure 2B for Figure 2A A partial stereoscopic diagram of a display device in FIG.

[0030] Figure 3 for Figure 1A A side view of the light guide plate and the columnar structure;

[0031] Figure 4 A simulation diagram of a display screen when a display device without a columnar structure is in a dark state;

[0032] Figure 5 is a simulation diagram of a display image when the display device according to an embodiment of the present disclosure is in a dark state;

[0033] Figure 6 is a simulation diagram of a display screen when the display device is in a dark state;

[0034] 7A to 7C Schematic diagram of a columnar structure according to different embodiments of the present disclosure.

[0035]

Explanation of symbols

[0036] 100, 100a: Display device

[0037] 110: Reflective display panel

[0038] 120: Light guide plate

[0039] 1202: Upper surface

[0040] 1204,1242: Lower surface

[0041] 1206: Light-entering surface

[0042] 122: Microstructure

[0043] 1222: first surface

[0044] 1224: Second surface

[0045] 124: Columnar structure

[0046] 1244,1244a,1244b,1244c: center angle

[0047] 130: Light source

[0048] 140: first optical adhesive layer

[0049] 150: Second optical adhesive layer

[0050] 160: Cover

[0051] N: Normal direction

[0052] D1: First direction

[0053] D2: Second direction

[0054] θ1: first angle

[0055] θ2: Second angle

[0056] θi: angle of incidence

[0057] LI: Incident light

[0058] LS: Divergent light

[0059] LR: reflected light

[0060] d,d1,d2,d3: depth

[0061] w,w1,w2,w3: width DETAILED DESCRIPTION

[0062] The following will disclose multiple embodiments of the present invention with the accompanying drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are not necessary. In addition, in order to simplify the drawings, some conventional structures and elements will be illustrated in a simple schematic manner in the drawings. And for the sake of clarity, the thickness of the layers and regions in the drawings may be exaggerated, and the same element symbols represent the same elements in the description of the drawings.

[0063] Figure 1A FIG. 1 is a side view of a display device 100 according to an embodiment of the present disclosure. Figure 1B for Figure 1AA partial stereoscopic view of the display device 100 in FIG. Figure 1B Only the light guide plate 120, the columnar structure 124, and the light source 130 are shown. The display device 100 includes a reflective display panel 110, a light guide plate 120, and a light source 130. The light guide plate 120 is located above the reflective display panel 110.

[0064] The light guide plate 120 has an upper surface 1202, a lower surface 1242, and a light incident surface 1206 connecting the upper surface 1202 and the lower surface 1242. The upper surface 1202 is a surface away from the reflective display panel 110, and the lower surface 1242 is a surface facing the reflective display panel 110. The columnar structure 124 of this embodiment is integrally formed with the light guide plate 120. Therefore, the columnar structure 124 protrudes toward the reflective display panel 110, and the lower surface 1242 of the light guide plate is the lower surface of the columnar structure 124.

[0065] The light guide plate 120 and the light source 130 constitute a front light module of the display device 100. The light guide plate 120 further includes a plurality of microstructures 122 located on the upper surface 1202 and a plurality of columnar structures 124 located on the lower surface 1242. The microstructures 122 are distributed in a dotted manner, and the columnar structures 124 are regularly arranged. The microstructures 122 are recessed from the upper surface 1202 of the light guide plate 120 toward the lower surface 1242.

[0066] The first optical adhesive layer 140 is located on the lower surface 1242 of the light guide plate 120 and contacts the columnar structure 124. The refractive index of the first optical adhesive layer 140 is lower than the refractive index of the light guide plate 120. The refractive index of the first optical adhesive layer 140 is less than 1.48.

[0067] Reference Figure 1B The light source 130 faces the light incident surface 1206 of the light guide plate 120. Specifically, the light source 130 is composed of a plurality of light emitting diodes (LEDs) forming a light bar. The light incident surface 1206 of the light guide plate 120 has a normal direction N, and the normal direction N is perpendicular to the first direction D1.

[0068] Reference Figure 1B . The columnar structures 124 are arranged in the first direction D1. In other words, the arrangement direction of the columnar structures 124 is the same as the extension direction of the light source 130. The normal direction N of the light guide plate 120 is perpendicular to the arrangement direction of the columnar structures 124. The columnar structures 124 extend in the second direction D2, and the normal direction N is parallel to the second direction D2. The columnar structure 124 in this embodiment takes a semi-cylindrical shape as an example, but the present disclosure is not limited to this. In other embodiments, the profile of the columnar structure may also include a triangular column shape or a semi-elliptical column shape.

[0069] Figure 2AFIG. 1 is a side view of a display device 100 a according to another embodiment of the present disclosure. Figure 2B for Figure 2A A partial stereoscopic view of the display device 100a in FIG. Figure 1A , Figure 1B The display device 100a is similar to the display device 100, but the difference is that the columnar structure 124 of the display device 100a is formed by first forming a layer of colloid on the lower surface 1204 of the light guide plate 120 and then forming it by embossing.

[0070] Figure 3 for Figure 1A 1 and 12. The side view of the light guide plate 120 and the columnar structure 124 in FIG. The columnar structure 124 has a central angle 1244, and the central angle 1244 is in the range of 30 degrees to 50 degrees. The columnar structure 124 has a width w, which is also equivalent to the width of the columnar structure 124 in the first direction D1. There is no gap between two adjacent columnar structures 124. The columnar structure 124 has a depth d, which is equivalent to the distance that the columnar structure 124 protrudes toward the reflective display panel 110. The aspect ratio of the depth d divided by the width w is in the range of 0.08 to 0.5.

[0071] Reference Figure 1A . The microstructure 122 has a first surface 1222 close to the light incident surface 1206 and a second surface 1224 away from the light incident surface 1206. A first angle θ1 is formed between the first surface 1222 and the upper surface 1202 of the light guide plate 120. A second angle θ2 is formed between the second surface 1224 and the upper surface 1202 of the light guide plate 120. The first angle θ1 is different from the second angle θ2. In other words, the microstructure 122 of the light guide plate 120 is asymmetric. The first angle θ1 is in the range of 20 degrees to 40 degrees. The second angle θ2 is in the range of 60 degrees to 89 degrees.

[0072] Reference Figure 1A . The display device 100 also includes a second optical adhesive layer 150. The second optical adhesive layer 150 is located on the upper surface 1202 of the light guide plate 120 and contacts the microstructure 122. The refractive index of the second optical adhesive layer 150 is lower than the refractive index of the light guide plate 120. The second optical adhesive layer 150 is filled between the first surface 1222 and the second surface 1224 of the microstructure 122. In other words, the medium between the microstructure 122 and the second optical adhesive layer 150 does not include air or vacuum. For example, the refractive index of the light guide plate 120 in this embodiment is approximately 1.58, and the refractive index of the second optical adhesive layer 150 is less than 1.48, but the present disclosure is not limited to this.

[0073] The display device 100 further includes a cover plate 160. The cover plate 160 includes a functional coating such as an anti-glare layer or a scratch-resistant layer. The display device 100 may also include a color filter, a touch module (not shown) and other structures.

[0074] Reference Figure 1A The microstructure 122 is configured to reflect the light from the light source 130 toward the reflective display panel 110. The difference in refractive index between the light guide plate 120 and the second optical adhesive layer 150 and the asymmetric design reduce the angle difference between the incident light LI and the vertical direction. The asymmetric microstructure 122 and the second optical adhesive layer 150 with a low refractive index (less than 1.48) allow the incident light LI to enter the reflective display panel 110 at an incident angle θi, thereby improving color saturation.

[0075] Generally speaking, if the columnar structure 124 is not configured, when the display device 100 is in a dark state, the incident light LI passing through the interface between the multilayer materials generates reflected light (not shown) which will form lines on the display screen, causing defects in display quality.

[0076] Figure 4 FIG. 1 is a simulation diagram of a display screen when the display device without the columnar structure 124 is in a dark state. The light guide plate 120 is only provided with the microstructure 122 (see FIG. 1 ). Figure 1A ), the consistency of the traveling direction of the incident light LI increases. The reflected light presents a periodic distribution in the first direction D1, so that the reflected light generates ray-like textures.

[0077] Reference Figure 2A and Figure 3 When the microstructure 122 of the light guide plate 120 is matched with the columnar structure 124, the incident light LI forms a divergent light LS traveling in different directions after passing through the columnar structure 124, thereby reducing the consistency of the traveling direction of the reflected light LR. In addition, the reflection efficiency of the reflected light LR can be improved by matching the columnar structure 124 with the first optical adhesive layer 140 with a low refractive index (less than 1.48). Since the columnar structure 124 occupies the entire lower surface 1204, the effect of reducing the consistency of the traveling direction of the reflected light LR can be improved.

[0078] Figure 5 This is a simulation diagram of a display screen when the display device according to an embodiment of the present disclosure is in a dark state. Figure 3 and Figure 5 When the light guide plate 120 is configured with both the microstructure 122 and the columnar structure 124, the reflected light LR is dispersed (see Figure 1A) is periodically distributed in the first direction D1 to generate radial lines. Therefore, when the display device 100 is in a dark state, no obvious radial lines will appear on the display screen, which can improve the display quality. In this embodiment, the first angle θ1 of the microstructure 122 is in the range of 25 degrees to 28 degrees, and the second angle θ2 is in the range of 85 degrees to 89 degrees. The central angle 1244 is 40 degrees.

[0079] Figure 6 It is a simulation diagram of the display screen when the display device is in a dark state. Figure 6 The central angle of the display device in the embodiment is greater than 50 degrees. The periodic distribution of the reflected light in the first direction D1 makes the reflected light produce ray-like patterns. It can be seen that when the central angle is too large, it is not conducive to reducing the consistency of the traveling direction of the reflected light.

[0080] Reference Figure 1A and Figure 3 . According to the above comparison, it can be known that the display device disclosed in the present invention is achieved by respectively arranging an asymmetric microstructure 122 and a columnar structure 124 on opposite sides of the light guide plate 120, thereby enhancing the color saturation of the display device and improving the display quality in the dark state. In addition, when the central angle 1244 of the columnar structure 124 is in the range of 30 degrees to 50 degrees, the consistency of the traveling direction of the reflected light can be effectively weakened. It should be noted that the function of the microstructure 122 is to converge the light and guide it to the reflective display panel 110, while the function of the columnar structure 124 is to disperse the light guided by the microstructure 122. In other words, the upper surface 1202 of the light guide plate 120 of the display device disclosed in the present invention is recessed toward the inside of the light guide plate 120, while the lower surface 1204 protrudes toward the outside of the light guide plate 120. In addition, the first optical adhesive layer 140 and the second optical adhesive layer 150 with low refractive index need to contact the lower surface 1204 and the upper surface 1202 to form an interface with a refractive index difference, so as to achieve the effect of enhancing the color saturation of the display device and improving the display quality in a dark state.

[0081] 7A to 7C Schematic diagram of a columnar structure according to different embodiments of the present disclosure. 7A to 7C The central angles 1244a, 1244b, and 1244c of the columnar structure are 30 degrees, 40 degrees, and 50 degrees, respectively. 7A to 7C The columnar structure can produce Figure 5 The effect of scattered light is shown.

[0082] Reference Fig. 7A The depth d1 of the columnar structure in this embodiment is 1.71 micrometers, the radius of curvature is 50 micrometers, and the width w1 in the first direction D1 is 25.9 micrometers. The aspect ratio of the depth d1 divided by the width w1 is 0.15. Figure 7BThe depth d2 of the columnar structure in this embodiment is 2.5 micrometers, the radius of curvature is 42.4 micrometers, and the width w2 in the first direction D1 is 29 micrometers. The aspect ratio of the depth d2 divided by the width w2 is 0.116. Figure 7C The columnar structure in this embodiment has a depth d3 of 2.8 micrometers, a radius of curvature of 30 micrometers, and a width w3 of 25.3 micrometers in the first direction D1. The aspect ratio of the depth d3 divided by the width w3 is 0.09.

[0083] According to the above, the columnar structure with a central angle of 30 to 50 degrees can achieve the effect of reducing the consistency of the traveling direction of the reflected light by matching different widths, depths and curvature radii. When the central angle of the columnar structure is less than 30 degrees or greater than 50 degrees, the light dispersion effect is weak or the light is excessively dispersed, resulting in poor effect of improving display quality.

[0084] In summary, the present disclosure uses the asymmetric microstructure on the upper surface of the light guide plate and the columnar structure on the lower surface of the light guide plate to make the incident light enter the reflective display panel nearly vertically, while reducing the consistency of the traveling direction of the reflected light. The first optical adhesive layer 140 with a low refractive index and the second optical adhesive layer 150 contact the lower surface 1204 and the upper surface 1202 to form an interface with a refractive index difference, thereby increasing the color saturation of the display device and improving the quality of the display image.

[0085] Although the present invention has been disclosed as above in the form of implementation modes, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the definition of the attached claims.

Claims

1. A display device, characterized in that: Include: a reflective display panel; A light guide plate is located above the reflective display panel, the light guide plate having an upper surface, a lower surface and a light incident surface connecting the upper surface and the lower surface, wherein the light guide plate further comprises: A plurality of microstructures are located on the upper surface; as well as A plurality of columnar structures are located on the lower surface; a light source facing the light incident surface of the light guide plate; as well as A first optical adhesive layer is located on the lower surface of the light guide plate and contacts the plurality of columnar structures, wherein the refractive index of the first optical adhesive layer is lower than the refractive index of the light guide plate.

2. The display device according to claim 1, wherein: The profiles of the plurality of columnar structures include semi-cylindrical, triangular columnar or semi-elliptical columnar.

3. The display device according to claim 1, wherein: There is no gap between any two adjacent columnar structures.

4. The display device according to claim 1, wherein: The plurality of microstructures are asymmetric.

5. The display device according to claim 1, wherein: The light incident surface has a normal direction, the plurality of columnar structures are arranged in a first direction and extend in a second direction, the first direction is perpendicular to the normal direction, and the normal direction is parallel to the second direction.

6. The display device according to claim 1, wherein: The plurality of columnar structures have a central angle in a range of 30 degrees to 50 degrees.

7. The display device according to claim 1, wherein: Each of the plurality of columnar structures has a width and a depth, and an aspect ratio of the depth divided by the width is in a range of 0.08 to 0.

5.

8. The display device according to claim 1, wherein: The plurality of columnar structures protrude from the lower surface of the light guide plate toward the reflective display panel, and the columnar structures and the light guide plate are formed as one piece.

9. The display device according to claim 1, wherein: The plurality of microstructures are recessed from the upper surface of the light guide plate toward the lower surface.

10. The display device according to claim 1, wherein: The plurality of microstructures have a first surface close to the light incident surface, and a first angle is formed between the first surface and the upper surface of the light guide plate, and the first angle is in a range of 20 degrees to 40 degrees.

11. The display device according to claim 1, wherein: The plurality of microstructures have a second surface away from the light incident surface, and a second angle is formed between the second surface and the upper surface of the light guide plate, and the second angle is in a range of 60 degrees to 89 degrees.

12. The display device according to claim 1, wherein: Also includes: A second optical adhesive layer is located on the upper surface of the light guide plate and contacts the plurality of microstructures, wherein the refractive index of the second optical adhesive layer is lower than the refractive index of the light guide plate.

13. A light guide plate for a reflective display device, the reflective display device comprising a reflective display panel, a light source facing the light guide plate, and an optical adhesive layer contacting a lower surface of the light guide plate, characterized in that: The light guide plate has a plurality of microstructures located on an upper surface, and a plurality of columnar structures located on the lower surface and arranged in a first direction.

14. The light guide plate according to claim 13, wherein: The plurality of microstructures are asymmetric.

15. The light guide plate according to claim 13, wherein: There is no gap between any two adjacent columnar structures.

16. The light guide plate according to claim 13, wherein: The plurality of columnar structures have a central angle in a range of 30 degrees to 50 degrees.

17. The light guide plate according to claim 13, wherein: Each of the plurality of columnar structures has a width and a depth, and an aspect ratio of the depth divided by the width is in a range of 0.08 to 0.

5.

18. The light guide plate according to claim 13, wherein: The plurality of columnar structures protrude from the lower surface of the light guide plate toward the reflective display panel, and the columnar structures and the light guide plate are formed as one piece.

19. The light guide plate according to claim 13, wherein: The plurality of microstructures are recessed from the upper surface of the light guide plate toward the lower surface.

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