Display device

Abstract

The invention provides a display device. The display device comprises a display panel, a front light module and a first adhesive layer, the display panel has a display surface. The front light module is arranged on one side of the display surface of the display panel and comprises a light guide plate, a light source and a first optical auxiliary layer. The light guide plate has a light incident surface and a first surface connected with the light incident surface and facing the display surface. The light source is arranged on one side of the incident surface of the light guide plate. The first optical auxiliary layer is arranged on one side of the first surface of the light guide plate and connected with the light guide plate. The first adhesive layer connects the display panel and the first optical auxiliary layer. The light guide plate, the first optical auxiliary layer and the first adhesive layer respectively have a first refractive index, a second refractive index and a third refractive index, and the second refractive index is greater than the first refractive index and the third refractive index.

Description

TECHNICAL FIELD

[0001] The present invention relates to a display device, and more particularly to a display device with a front light module. BACKGROUND

[0002] Reflective or transflective display devices have gradually attracted attention due to their low power consumption operation. In order to maintain the display quality in the case of insufficient ambient light, such display devices are usually provided with a front light source to meet the lighting requirements during display. However, the fixed relationship between the light guide structure and the display panel can easily cause a decrease in display quality or light guide efficiency. SUMMARY

[0003] The present invention is directed to a display device with a front light module having a better light guide efficiency.

[0004] According to an embodiment of the present invention, a display device includes a display panel, a front light module, and a first adhesive layer. The display panel has a display surface. The front light module is disposed on a side of the display surface of the display panel, and includes a light guide plate, a light source, and a first optical auxiliary layer. The light guide plate has an incident surface and a first surface connected to the incident surface and facing the display surface. The light source is disposed on a side of the incident surface of the light guide plate. The first optical auxiliary layer is disposed on a side of the first surface of the light guide plate and connected to the light guide plate. The first adhesive layer connects the display panel and the first optical auxiliary layer. The light guide plate, the first optical auxiliary layer, and the first adhesive layer have a first refractive index, a second refractive index, and a third refractive index, respectively, and the second refractive index is greater than the first refractive index and the third refractive index.

[0005] In the display device according to the embodiment of the present invention, an absolute difference between the second refractive index and the third refractive index is greater than an absolute difference between the first refractive index and the second refractive index.

[0006] In the display device according to the embodiment of the present invention, the front light module further includes a cover plate, a second optical auxiliary layer, and a second adhesive layer. The cover plate is disposed on a side of a second surface of the light guide plate. The second surface is opposite to the first surface. The second optical auxiliary layer is disposed between the light guide plate and the cover plate and connected to the second surface of the light guide plate. The second adhesive layer connects the cover plate and the second optical auxiliary layer. The second optical auxiliary layer and the second adhesive layer have a fourth refractive index and a fifth refractive index, respectively, and the fourth refractive index is greater than the first refractive index and the fifth refractive index.

[0007] In the display device according to the embodiment of the present invention, an absolute difference between the fourth refractive index and the fifth refractive index is greater than an absolute difference between the first refractive index and the fourth refractive index.

[0008] In the display device according to the embodiment of the present invention, a plurality of surface microstructures are disposed on the second surface of the light guide plate, the second optical auxiliary layer directly covers the plurality of surface microstructures, and the second adhesive layer fills the plurality of surface microstructures.

[0009] In the display device according to the embodiment of the present application, the front light module further comprises a cover plate and a frame. The cover plate is disposed on one side of the second surface of the light guide plate. The second surface is opposite to the first surface. The frame connects the cover plate and the light guide plate, and defines an air layer. The air layer exposes the portion of the second surface of the light guide plate that overlaps the display surface.

[0010] In the display device according to the embodiment of the present application, the front light module further comprises a second optical auxiliary layer disposed between the air layer and the light guide plate, and connected to the second surface of the light guide plate. The second optical auxiliary layer and the air layer have a fourth refractive index and an air refractive index, respectively, and the fourth refractive index is greater than the first refractive index and the air refractive index.

[0011] In the display device according to the embodiment of the present application, the absolute difference between the fourth refractive index and the air refractive index is greater than the absolute difference between the first refractive index and the fourth refractive index.

[0012] In the display device according to the embodiment of the present application, the absolute difference between the fourth refractive index and the air refractive index is greater than the absolute difference between the first refractive index and the air refractive index.

[0013] In the display device according to the embodiment of the present application, the second surface of the light guide plate is provided with a plurality of surface microstructures. The second optical auxiliary layer directly covers the plurality of surface microstructures, and the orthographic projection of the frame on the second surface does not overlap the plurality of surface microstructures.

[0014] Based on the above, in the display device according to the embodiment of the present application, the fixed relationship between the light guide plate of the front light module and the display panel is achieved through the adhesive layer. By disposing the optical auxiliary layer between the adhesive layer and the light guide plate, and the refractive index of the optical auxiliary layer being greater than the refractive indices of the adhesive layer and the light guide plate, respectively, the light guide efficiency of the light guide plate can be effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a cross-sectional schematic view of a display device according to a first embodiment of the present application;

[0016] Figure 2 is a cross-sectional schematic view of a display device according to a second embodiment of the present application;

[0017] Figure 3 is a cross-sectional schematic view of a display device according to a third embodiment of the present application.

[0018] REFERENCE NUMERALS

[0019] 10, 20, 20A: display device;

[0020] 100: display panel;

[0021] 100ds: display surface;

[0022] 150: first adhesive layer;

[0023] 200, 200A, 200B: front light module;

[0024] 210: light guide plate;

[0025] 210is: light incident surface;

[0026] 210si: first surface;

[0027] 210s2: second surface;

[0028] 220: light source;

[0029] 231: first optical auxiliary layer;

[0030] 232: second optical auxiliary layer;

[0031] 240: second adhesive layer;

[0032] 250: cover plate;

[0033] 260: frame;

[0034] 270: air layer;

[0035] MS: surface microstructure;

[0036] Z: direction. DETAILED DESCRIPTION

[0037] Reference will now be made in detail to the exemplary embodiments of the present application, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

[0038] Reference will now be made in detail to the exemplary embodiments of the present application, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

[0039] The foregoing and other technical contents, features and effects of the present application will become apparent from the following detailed description of a preferred embodiment with reference to the attached drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only reference directions of the drawings. Therefore, the directional terms are used to explain, not to limit the present application.

[0040] Figure 1 is a cross-sectional schematic view of a display device according to the first embodiment of the present application. Please refer to Figure 1The display device 10 includes a display panel 100, a front light module 200, and a first adhesive layer 150. The display panel 100 is, for example, a reflective display panel or a transflective display panel, and has a display surface 100ds. The front light module 200 is disposed at one side of the display surface 100ds of the display panel 100, and overlaps the display surface 100ds along a normal direction (e.g., direction Z) of the display surface 100ds. In the present embodiment, the front light module 200 can serve as a front light source of the display panel 100 to satisfy the illumination requirement of insufficient ambient light during display. It is noted that, unless otherwise specified, the overlapping relationship between two components is defined by the aforementioned overlapping direction, and will not be repeated hereinafter.

[0041] In detail, the front light module 200 can include a light guide plate 210 and a light source 220. The light guide plate 210 has an incident surface 210is and a first surface 210s1 connected to the incident surface 210is and facing the display surface 100ds of the display panel 100. The light source 220 is disposed at one side of the incident surface 210is of the light guide plate 210, and is adjacent to the incident surface 210is. The display panel 100 is disposed at one side of the first surface 210s1 of the light guide plate 210. The material of the light guide plate 210 includes, for example, glass, polycarbonate (PC), poly(methyl methacrylate) (PMMA), or other suitable optical-grade plate materials.

[0042] The first adhesive layer 150 is disposed at one side of the first surface 210s1 of the light guide plate 210, and is used to connect the light guide plate 210 and the display panel 100. That is, the first adhesive layer 150 is used to achieve a fixed relationship between the light guide plate 210 and the display panel 100. The material of the first adhesive layer 150 includes, for example, optically clear adhesive (OCA) or optically clear resin (OCR).

[0043] It is particularly noted that a first optical auxiliary layer 231 is provided between the first adhesive layer 150 and the light guide plate 210, and directly covers the first surface 210s1 of the light guide plate 210. The first adhesive layer 150 connects the display panel 100 and the first optical auxiliary layer 231, and connects the light guide plate 210 via the first optical auxiliary layer 231.

[0044] In the present embodiment, the light guide plate 210, the first optical auxiliary layer 231, and the first adhesive layer 150 have a first refractive index, a second refractive index, and a third refractive index, respectively, and the second refractive index of the first optical auxiliary layer 231 is greater than the first refractive index of the light guide plate 210 and the third refractive index of the first adhesive layer 150. Preferably, the absolute difference between the second refractive index and the third refractive index can be greater than the absolute difference between the first refractive index and the second refractive index.

[0045] Due to the large difference in refractive index between the first optical auxiliary layer 231 and the first adhesive layer 150, the opportunity of total reflection of the light rays passing through the first optical auxiliary layer 231 from the light guide plate 210 at the interface between the first adhesive layer 150 and the first optical auxiliary layer 231 can be effectively increased, thereby improving the light guide efficiency of the light guide plate 210. From another point of view, the problem of the incident angle of the light rays becoming large when the first adhesive layer 150 directly connects the first surface 210s1 of the light guide plate 210 can be solved.

[0046] Further, in order to avoid damage to the light guide plate 210 due to operation or unexpected external force intervention, the front light module 200 can also be provided with a cover plate 250 on the side opposite to the display panel 100. Or in other words, the cover plate 250 is provided on the side of the second surface 210s2 of the light guide plate 210, wherein the second surface 210s2 is opposite to the first surface 210s1. In order to fix the cover plate 250 on the light guide plate 210, the front light module 200 can also include a second adhesive layer 240 provided between the light guide plate 210 and the cover plate 250. The material of the second adhesive layer 240 includes, for example, optically clear adhesive (OCA) or optically clear resin (OCR).

[0047] It is particularly noted that a second optical auxiliary layer 232 can also be provided between the second adhesive layer 240 and the light guide plate 210, and the second optical auxiliary layer 232 directly connects the light guide plate 210. More specifically, the second optical auxiliary layer 232 directly covers the second surface 210s2 of the light guide plate 210. The second adhesive layer 240 connects the cover plate 250 and the second optical auxiliary layer 232, and connects the light guide plate 210 through the second optical auxiliary layer 232.

[0048] In the present embodiment, the second optical auxiliary layer 232 and the second adhesive layer 240 have a fourth refractive index and a fifth refractive index, respectively, and the fourth refractive index of the second optical auxiliary layer 232 is greater than the fifth refractive index of the second adhesive layer 240. Preferably, the absolute difference between the fourth refractive index and the fifth refractive index can be greater than the absolute difference between the first refractive index and the fourth refractive index.

[0049] Due to the large difference in refractive index between the second optical auxiliary layer 232 and the second adhesive layer 240, the chance of total reflection of the light rays passing through the second optical auxiliary layer 232 at the interface between the second adhesive layer 240 and the second optical auxiliary layer 232 can be effectively increased, thereby improving the light guiding efficiency of the light guide plate 210. In another aspect, the problem of the incident angle of the light rays becoming large when the second adhesive layer 240 is directly connected to the second surface 210s2 of the light guide plate 210 can be solved.

[0050] Further, the second surface 210s2 of the light guide plate 210 can be provided with a plurality of surface microstructures MS, and the surface microstructures MS overlap the display surface 100ds of the display panel 100 along the normal direction of the display surface 100ds. It is particularly noted that the second optical auxiliary layer 232 directly covers the surface microstructures MS on the second surface 210s2 of the light guide plate 210, and the second adhesive layer 240 fills the surface microstructures MS, but is not limited thereto. That is, in the present embodiment, the cover plate 250 is fixed on the light guide plate 210 in a direct bond manner.

[0051] By providing the second optical auxiliary layer 232, the plurality of surface microstructures MS can also ensure the deflection effect of the light rays passing through the light guide plate 210, thereby improving the light extraction efficiency and uniformity of the front light module 200.

[0052] Some other embodiments will be described below to illustrate the present disclosure in detail, wherein the same components will be denoted by the same reference signs, and the description of the same technical content will be omitted. Please refer to the foregoing embodiments for the omitted parts, which will not be described again.

[0053] Figure 2 is a cross-sectional view of a display device according to a second embodiment of the present disclosure. Please refer to Figure 2 , the display device 20 of the present embodiment is different from the display device 10 of Figure 1 in that the bonding manner of the cover plate and the light guide plate is different. Specifically, in the present embodiment, the cover plate 250 is fixed on the light guide plate 210 in a frame bonding manner. For example, the front light module 200A of the display device 20 can further include a rubber frame 260 arranged between the cover plate 250 and the light guide plate 210. The rubber frame 260 can be a mouth-shaped rubber (band), but is not limited thereto.

[0054] In particular, the glue frame 260 does not overlap the plurality of surface microstructures MS in the orthographic projection on the second surface 210s2 of the light guide plate 210. More specifically, the glue frame 260 can be disposed around the surface microstructures MS and define an air layer 270. The air layer 270 exposes the portion of the second surface 210s2 of the light guide plate 210 that overlaps the display surface 100ds and the surface microstructures MS.

[0055] Since the active area of the second surface 210s2 of the light guide plate 210 (i.e., the area not overlapped by the glue frame 260) is directly exposed by the air layer 270, the air layer 270 has a large difference in refractive index with the light guide plate 210. Therefore, the front light module 200A of the present embodiment does not need to be provided with a second optical auxiliary layer 232 on the side of the second surface 210s2 of the light guide plate 210. Figure 1

[0056] Figure 3 is a cross-sectional view of a display device according to a third embodiment of the present application. Please refer to Figure 3 , compared to the display device 20 of Figure 2 , the front light module 200B of the display device 20A of the present embodiment can further include a second optical auxiliary layer 232 disposed between the air layer 270 and the light guide plate 210 and connected to the second surface 210s2 of the light guide plate 210. More specifically, the second optical auxiliary layer 232 directly covers the second surface 210s2 of the light guide plate 210. The glue frame 260 is connected to the light guide plate 210 via the second optical auxiliary layer 232.

[0057] In the present embodiment, the second optical auxiliary layer 232 and the air layer 270 have a fourth refractive index and an air refractive index, respectively, and the fourth refractive index of the second optical auxiliary layer 232 is greater than the first refractive index of the light guide plate 210 and the air refractive index of the air layer 270. Preferably, the absolute difference between the fourth refractive index and the air refractive index can be greater than the absolute difference between the first refractive index and the fourth refractive index and the absolute difference between the first refractive index and the air refractive index. Since the second optical auxiliary layer 232 and the air layer 270 have a large difference in refractive index, the chance of total reflection of the light rays passing through the second optical auxiliary layer 232 from the light guide plate 210 at the interface between the air layer 270 and the second optical auxiliary layer 232 can be effectively increased, thereby improving the light guiding efficiency of the light guide plate 210.

[0058] From another point of view, although the difference in refractive index between the light guide plate 210 and the air layer 270 has been significantly greater than the difference in refractive index between the light guide plate 210 and the glue frame 260, the light guiding efficiency of the light guide plate 210 can still be improved by the provision of the second optical auxiliary layer 232. Figure 1 ​The difference of the refractive index of the second adhesive layer 240 of the light guide plate 210 is large, but the front light module 200B of the present embodiment can still be provided with the second optical auxiliary layer 232 between the air layer 270 and the light guide plate 210, so as to further improve the total reflection efficiency of the light transmitted in the light guide plate 210 on the side of the second surface 210s2, thereby further improving the light guide efficiency of the light guide plate 210.

[0059] In summary, in the display device of the embodiment of the present application, the fixed relationship between the light guide plate of the front light module and the display panel is achieved through the adhesive layer. By providing the optical auxiliary layer between the adhesive layer and the light guide plate, and the refractive index of the optical auxiliary layer is greater than the refractive index of the adhesive layer and the light guide plate respectively, the light guide efficiency of the light guide plate can be effectively improved.

[0060] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A display device, characterized by comprising: The display panel has a display surface. The front light module is disposed on one side of the display surface of the display panel and includes: A light guide plate having an incident surface and a first surface connected to the incident surface and facing the display surface; A light source disposed on one side of the incident surface of the light guide plate; and A first optical auxiliary layer disposed on one side of the first surface of the light guide plate and connected to the light guide plate; and A first adhesive layer connecting the display panel and the first optical auxiliary layer, wherein the light guide plate, the first optical auxiliary layer, and the first adhesive layer have first, second, and third refractive indices, respectively, and the second refractive index is greater than the first and third refractive indices. The absolute difference between the second and third refractive indices is greater than the absolute difference between the first and second refractive indices.

2. The display device according to claim 1, wherein The front light module further includes:

3. The display device according to claim 1, wherein A cover plate disposed on one side of a second surface of the light guide plate, the second surface being opposite to the first surface; A second optical auxiliary layer disposed between the light guide plate and the cover plate and connected to the second surface of the light guide plate; and A second adhesive layer connecting the cover plate and the second optical auxiliary layer, wherein the second optical auxiliary layer and the second adhesive layer have fourth and fifth refractive indices, respectively, and the fourth refractive index is greater than the first and fifth refractive indices. The absolute difference between the fourth and fifth refractive indices is greater than the absolute difference between the first and fourth refractive indices.

4. The display device according to claim 3, wherein The second surface of the light guide plate is provided with a plurality of surface microstructures, the second optical auxiliary layer directly covers the plurality of surface microstructures, and the second adhesive layer fills the plurality of surface microstructures.

5. The display device according to claim 3, wherein The front light module further includes:

6. The display device according to claim 1, wherein A cover plate disposed on one side of a second surface of the light guide plate, the second surface being opposite to the first surface; and A frame connecting the cover plate and the light guide plate and defining an air layer, wherein the air layer exposes the portion of the second surface of the light guide plate overlapping the display surface. The front light module further includes:

7. The display device according to claim 6, wherein A second optical auxiliary layer disposed between the air layer and the light guide plate and connected to the second surface of the light guide plate, wherein the second optical auxiliary layer and the air layer have fourth and air refractive indices, respectively, and the fourth refractive index is greater than the first and air refractive indices. The absolute difference between the fourth and air refractive indices is greater than the absolute difference between the first and fourth refractive indices.

8. The display device according to claim 7, wherein The absolute difference between the fourth and air refractive indices is greater than the absolute difference between the first and air refractive indices.

9. The display device according to claim 8, wherein The second surface of the light guide plate is provided with a plurality of surface microstructures, the second optical auxiliary layer directly covers the plurality of surface microstructures, and the orthogonal projection of the frame on the second surface does not overlap the plurality of surface microstructures.

10. The display device according to claim 7, wherein ​

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