Front light module

Abstract

The invention provides a front light module which is suitable for being arranged on a display surface of a display panel. The front light module comprises a light guide plate, a light source, a plurality of micro grooves, a light-transmitting base material and a first adhesive layer, the first surface and the second surface are connected with the light incident surface and are opposite to each other. The first surface faces the display surface of the display panel. The light source is arranged on one side of the incident surface of the light guide plate. The plurality of micro grooves are arranged on the second surface of the light guide plate and are recessed from the second surface. The light-transmitting base material is arranged on one side of the second surface of the light guide plate. The first adhesive layer is arranged between the light-transmitting base material and the light guide plate and is connected with the light-transmitting base material and the light guide plate. The unfilled parts in the plurality of micro-grooves define a plurality of gaps, and the ratio of the volume of the gaps to the volume of the micro-grooves is greater than or equal to 0.9 and less than or equal to 1.

Description

Technical Field

[0001] The present invention relates to a light source module, in particular to a front light module. Background Art

[0002] Reflective or transflective display devices are gaining popularity due to their low-energy operation. To maintain display quality in low ambient light conditions, these displays often incorporate a front light source to provide illumination. To protect the front light's light-guiding structure, a cover plate is typically installed on the side facing away from the display panel. However, the fixed connection between the cover plate and the light-guiding structure can easily compromise display quality and light-guiding efficiency. Summary of the Invention

[0003] The present invention is directed to a front light module, which has good protection performance and can take into account the light guiding effect of a light guide plate.

[0004] According to an embodiment of the present invention, the front light module is suitable for being arranged on the display surface of the display panel, and includes a light guide plate, a light source, a plurality of micro grooves, a light-transmitting substrate and a first adhesive layer. The light guide plate has a light incident surface and a first surface and a second surface connected to the light incident surface and opposite to each other. The first surface faces the display surface of the display panel. The light source is arranged on one side of the light incident surface of the light guide plate. A plurality of micro grooves are arranged on the second surface of the light guide plate and are recessed from the second surface. The light-transmitting substrate is arranged on one side of the second surface of the light guide plate. The first adhesive layer is arranged between the light-transmitting substrate and the light guide plate, and connects the light-transmitting substrate and the light guide plate. The unfilled portions in the plurality of micro grooves define a plurality of gaps, and the ratio of the volume of these gaps to the volume of these micro grooves is greater than or equal to 0.9 and less than or equal to 1.

[0005] A front light module according to an embodiment of the present invention further includes a cover plate and a second adhesive layer. The cover plate is disposed on a side of the light-transmitting substrate opposite the first adhesive layer. The second adhesive layer is disposed between the cover plate and the light-transmitting substrate and connects the cover plate and the light-transmitting substrate. The first adhesive layer is different from the second adhesive layer.

[0006] In the front light module according to the embodiment of the present invention, the loss tangent of the viscoelasticity of the first adhesive layer is smaller than the loss tangent of the viscoelasticity of the second adhesive layer.

[0007] In the front light module according to the embodiment of the present invention, the loss tangent of the viscoelasticity of the first adhesive layer at a temperature of 25 degrees Celsius is greater than or equal to 0.1 and less than or equal to 0.2.

[0008] In the front light module according to an embodiment of the present invention, the first adhesive layer has a portion extending into each groove, and the percentage of the orthographic projection area of ​​the aforementioned portion of the first adhesive layer on a cross-section perpendicular to the light incident surface and the second surface of the light guide plate to the orthographic projection area of ​​each micro-groove on the cross-section is less than or equal to 15%.

[0009] In the front light module according to the embodiment of the present invention, a plurality of protruding structures are provided on the surface of the light-transmitting substrate facing the light guide plate, and the protruding structures extend into the plurality of micro grooves respectively.

[0010] In a front light module according to an embodiment of the present invention, each of the plurality of raised structures has a portion extending into a corresponding one of the plurality of micro-grooves. The portion of each of the raised structures has a first thickness along a direction normal to the surface. Each of the raised structures has a second thickness along the direction normal to the surface, and the percentage of the first thickness to the second thickness is less than or equal to 10%.

[0011] In the front light module according to the embodiment of the present invention, a difference between the refractive index of the plurality of protrusion structures and the refractive index of the first adhesive layer is less than or equal to 0.15.

[0012] In a front light module according to an embodiment of the present invention, a plurality of raised structures are provided on a surface of a light-transmitting substrate facing the light guide plate. A first adhesive layer is positioned between these raised structures. The orthographic projections of the plurality of microgrooves on the surface of the light-transmitting substrate are positioned within the orthographic projections of the raised structures on the surface of the light-transmitting substrate.

[0013] In the front light module according to the embodiment of the present invention, the light guide plate further has a plurality of optical surfaces defining a plurality of micro grooves, and each of the optical surfaces of the micro grooves is covered with a hydrophobic layer.

[0014] In a front light module according to an embodiment of the present invention, the first adhesive layer has a thickness along a direction normal to a surface of the light-transmitting substrate facing the light guide plate. Each micro-groove has a depth along the direction normal to the surface of the light-transmitting substrate, and a ratio of the depth of each micro-groove to the thickness of the first adhesive layer is greater than 5.7.

[0015] In the front light module according to the embodiment of the present invention, the cross-sectional profile of each micro-groove is asymmetric.

[0016] In a front light module according to an embodiment of the present invention, the light guide plate further comprises an optical surface defining the microgrooves and a back surface connected to the optical surface. The optical surface faces the light incident surface, and the back surface faces away from the light incident surface. The cross-sectional profile of the optical surface is longer than the cross-sectional profile of the back surface.

[0017] Based on the above, in a frontlight module according to one embodiment of the present invention, a light guide plate (LGP) is provided with a plurality of micro-grooves and a light-transmitting substrate on the side facing away from the display panel. An adhesive layer is provided between these micro-grooves and the light-transmitting substrate, and at least a majority of the volume of these micro-grooves is not filled by the adhesive layer. This ensures that the light guide plate is protected while also ensuring efficient light extraction from the LGP. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic cross-sectional view of a display device according to a first embodiment of the present invention;

[0019] Figure 2 is a schematic cross-sectional view of a display device according to a second embodiment of the present invention;

[0020] Figure 3 is a schematic cross-sectional view of a display device according to a third embodiment of the present invention;

[0021] Figure 4 is a schematic cross-sectional view of a display device according to a fourth embodiment of the present invention;

[0022] Figure 5 is a schematic cross-sectional view of a display device according to a fifth embodiment of the present invention;

[0023] Figure 6 yes Figure 5 A cross-sectional schematic diagram of part of the manufacturing process of the front light module;

[0024] Figure 7 is a schematic cross-sectional view of a display device according to a sixth embodiment of the present invention;

[0025] Figure 8 is a schematic cross-sectional view of a display device according to a seventh embodiment of the present invention.

[0026] Description of Reference Numerals

[0027] 10, 10A, 10B, 10C, 10D, 10E, 10F: display device;

[0028] 100, 100A, 100B: light guide plate;

[0029] 100is: light incident side;

[0030] 121, 122, 125, 121D: adhesive layer;

[0031] 121p, PSp: part;

[0032] 150: light-transmitting substrate;

[0033] 150s: surface;

[0034] 200: cover plate;

[0035] 300: microlens array;

[0036] BS: back;

[0037] CL: curing light;

[0038] DP: display panel;

[0039] DS: display surface;

[0040] DT, DT”: depth;

[0041] FLM, FLM-A, FLM-B, FLM-C, FLM-D: front light module;

[0042] G, G”: gap;

[0043] HS: hydrophobic layer;

[0044] L1, L2: length;

[0045] LB: light;

[0046] LS: light source;

[0047] MG, MG-A, MG-B: microgrooves;

[0048] ML: microlens;

[0049] OS, OS”: optical surface;

[0050] PS, PS-A: convex structure;

[0051] SF1: first surface;

[0052] SF2: second surface;

[0053] t1, t2, TH: thickness. DETAILED DESCRIPTION

[0054] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0055] The foregoing and other technical aspects, features, and benefits of the present invention will be more clearly understood in the following detailed description of a preferred embodiment with reference to the accompanying drawings. Directional terms such as up, down, left, right, front, and back, used in the following embodiments, are merely references to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes only and are not intended to limit the present invention.

[0056] Figure 1is a cross-sectional view of a display device according to a first embodiment of the present invention. Figure 1 The display device 10 includes a frontlight module FLM and a display panel DP. The frontlight module FLM is disposed on one side of the display surface DS of the display panel DP. The display panel DP is, for example, a reflective display panel or a transflective display panel. In other words, the display panel DP is a non-self-luminous display panel. Alternatively, the display panel DP may be a liquid crystal display panel or an electrophoretic display panel, but is not limited thereto.

[0057] The frontlight module FLM includes a light guide plate 100, a light source LS, and a plurality of microgrooves MG. The light guide plate 100 has a light incident surface 100is, and a first surface SF1 and a second surface SF2 connecting the light incident surface 100is and opposing each other. The first surface SF1 faces the display surface DS of the display panel DP. The second surface SF2 faces away from the display surface DS. The light source LS is disposed on one side of the light incident surface 100is of the light guide plate 100. A plurality of microgrooves MG are disposed on the second surface SF2 of the light guide plate 100 and are recessed from the second surface SF2.

[0058] The light guide plate 100 further includes a plurality of optical surfaces OS defining a plurality of microgrooves MG. These optical surfaces OS are adapted to reflect light LB from the light source LS and transmitted within the light guide plate 100 toward the display surface DS of the display panel DP. In this embodiment, the optical surfaces OS are, for example, planes inclined relative to the second surface SF2 of the light guide plate 100, but are not limited thereto.

[0059] For example, in this embodiment, the cross-sectional profile of the micro-groove MG is triangular, but the present invention is not limited thereto. In other embodiments not shown, the cross-sectional profile of the micro-groove may also be semicircular, trapezoidal, or other shapes suitable for guiding light toward the display panel DP. The aforementioned cross-sectional profile is, for example, a virtual plane perpendicular to the light incident surface 100is of the light guide plate 100 and the second surface SF2.

[0060] The front light module FLM further includes a transparent substrate 150 and a first adhesive layer 121, disposed on one side of the second surface SF2 of the light guide plate 100. The first adhesive layer 121 is located between the transparent substrate 150 and the light guide plate 100, connecting the two. In other words, the transparent substrate 150 is attached to the light guide plate 100 via the first adhesive layer 121.

[0061] The material of the light-transmitting substrate 150 includes, for example, polyethylene terephthalate (PET), poly(methyl methacrylate) (PMMA), polycarbonate (PC), or other suitable flexible plastic materials. The material of the first adhesive layer 121 includes, for example, an optically clear adhesive (OCA), an optically clear resin (OCR), or other suitable light-curing adhesive materials. For example, in the stacking direction of the light-transmitting substrate 150 and the first adhesive layer 121, the thickness of the light-transmitting substrate 150 can be greater than or equal to 25 microns and less than or equal to 100 microns, and the thickness of the first adhesive layer 121 can be greater than or equal to 5 microns and less than or equal to 50 microns, but the present invention is not limited thereto.

[0062] It is particularly noted that in this embodiment, the first adhesive layer 121 has a portion 121p extending into each micro-groove MG, and the percentage of the orthographic projection area of ​​the portion 121p of the first adhesive layer 121 on a cross section perpendicular to the light incident surface 100is of the light guide plate 100 and the second surface SF2 to the orthographic projection area of ​​each micro-groove MG on this cross section is less than or equal to 15%.

[0063] From another perspective, the unfilled portions of the plurality of microgrooves MG define a plurality of gaps G, and the ratio of the volume of the gaps G to the volume of the microgrooves MG is greater than or equal to 0.9 and less than or equal to 1. In other words, in this embodiment, although the first adhesive layer 121 can extend into the plurality of microgrooves MG, most of the volume of the microgrooves MG is not filled by the first adhesive layer 121.

[0064] In this embodiment, the first adhesive layer 121 may have better elasticity to prevent the micro grooves MG from being filled by the first adhesive layer 121. For example, the loss tangent of the viscoelasticity of the first adhesive layer 121 at 25 degrees Celsius may be greater than or equal to 0.1 and less than or equal to 0.2, but the present invention is not limited thereto.

[0065] Since the gaps G expose the optical surfaces OS of the light guide plate 100 , there is a significant difference in the refractive index of the two media on opposite sides of the optical surface OS, thereby allowing the light LB transmitted in the light guide plate 100 to be totally reflected after entering the optical surface OS and guided to the display surface DS of the display panel DP.

[0066] Furthermore, the front light module FLM may further include a cover plate 200 and a second adhesive layer 122 disposed on the side of the light-transmitting substrate 150 facing away from the first adhesive layer 121. The second adhesive layer 122 is positioned between the light-transmitting substrate 150 and the cover plate 200, connecting the light-transmitting substrate 150 and the cover plate 200. In other words, the cover plate 200 is attached to the light-transmitting substrate 150 via the second adhesive layer 122. The material of the second adhesive layer 122 includes, for example, pressure-sensitive adhesive (PSA), silicone, acrylic resin, unsaturated polyester, polyurethane, epoxy resin, or other suitable non-photocuring adhesives.

[0067] For example, in the stacking direction of the light-transmitting substrate 150 and the second adhesive layer 122, the thickness of the second adhesive layer 122 can be greater than or equal to 25 microns and less than or equal to 1 mm, but is not limited thereto. Preferably, the thickness of the second adhesive layer 122 can be greater than the thickness of the first adhesive layer 121.

[0068] From another perspective, the loss tangent of the viscoelasticity of the second adhesive layer 122 at a temperature of 25 degrees Celsius may be greater than or equal to 0.15 and less than or equal to 0.4. Preferably, the loss tangent of the viscoelasticity of the first adhesive layer 121 at a temperature of 25 degrees Celsius may be less than the loss tangent of the viscoelasticity of the second adhesive layer 122 at a temperature of 25 degrees Celsius. In other words, the second adhesive layer 122 may have less elasticity than the first adhesive layer 121.

[0069] In particular, the provision of the cover plate 200 further enhances the protection of the front light module FLM. Compared to the second adhesive layer 122, the thinner and more flexible first adhesive layer 121 prevents the first adhesive layer 121 from filling the multiple micro-grooves MG on the light guide plate 100 and affecting light extraction efficiency. Compared to the first adhesive layer 121, the thicker second adhesive layer 122 not only serves to attach the cover plate 200 but also compensates for uneven height differences between the cover plate 200 and the light guide plate 100, preventing the formation of bubbles that could affect visual quality.

[0070] In this embodiment, to attach the front light module FLM to the display panel DP, the display device 10 further includes a third adhesive layer 125 connected between the display surface DS of the display panel DP and the first surface SF1 of the light guide plate 100. The third adhesive layer 125 may be made of, for example, an optically clear adhesive (OCA), an optically clear resin (OCR), or other suitable photocurable adhesive. In the normal direction of the display surface DS, the thickness of the third adhesive layer 125 may be greater than or equal to 25 microns and less than or equal to 1 millimeter, but is not limited thereto.

[0071] The following will list some other embodiments to illustrate the present disclosure in detail, wherein the same components will be marked with the same symbols, and the description of the same technical content will be omitted. For the omitted parts, please refer to the above embodiments and will not be repeated below.

[0072] Figure 2 is a cross-sectional view of a display device according to a second embodiment of the present invention. Figure 2 , compared to Figure 1 Regarding the front light module FLM, in the display device 10A of this embodiment, the front light module FLM-A may further include a plurality of protrusion structures PS disposed on a surface 150s of the light-transmitting substrate 150 facing the light guide plate 100, and the first adhesive layer 121 is located between the protrusion structures PS.

[0073] Of particular note, each of these protrusion structures PS has a portion PSp that extends into a corresponding one of the plurality of microgrooves MG. The portion PSp of each of these protrusion structures PS that extends into the microgrooves MG has a first thickness t1 along the normal direction of the surface 150s of the light-transmitting substrate 150. Each protrusion structure PS has a second thickness t2 along the normal direction of the surface 150s. The percentage of the first thickness t1 to the second thickness t2 can be less than or equal to 10%. This ensures that the microgrooves MG are not excessively occupied by the protrusion structures PS, thereby affecting the light extraction efficiency of the light guide plate 100.

[0074] To reduce unnecessary or unintended refraction or reflection of light caused by the curved surface between the protrusion structures PS and the first adhesive layer 121, the refractive indices of the protrusion structures PS and the first adhesive layer 121 may be equal, but not limited to this. In the present invention, the difference in refractive index between the protrusion structures PS and the first adhesive layer 121 may be less than 0.15. Under these conditions, the refraction and reflection of light at the interface between the protrusion structures PS and the first adhesive layer 121 will remain within an acceptable range for the user viewing the display panel DP through the frontlight module FLM-A.

[0075] On the other hand, in this embodiment, the orthographic projections of the plurality of micro-grooves MG on the surface 150s of the light-transmitting substrate 150 are respectively located within the orthographic projections of the plurality of protrusion structures PS on the surface 150s of the light-transmitting substrate 150. This ensures that the first adhesive layer 121 does not penetrate into the micro-grooves MG and cover the optical surface OS, thereby affecting the light extraction efficiency of the light guide plate 100.

[0076] Figure 3 is a cross-sectional view of a display device according to a third embodiment of the present invention. Figure 3 The display device 10B of this embodiment is Figure 2 The only difference between the display device 10A and the front light module FLM-B is that the configuration of the protruding structure is different. Specifically, in this embodiment, the protruding structure PS-A of the front light module FLM-B does not extend into the multiple micro-grooves MG of the light guide plate 100. In other words, the ratio of the volume of the multiple protruding structures PS-A and the multiple gaps G" defined by the light guide plate 100 to the volume of the multiple micro-grooves MG in this embodiment is substantially equal to 1. Accordingly, it is ensured that the entire volume of these micro-grooves MG will not be occupied by the multiple protruding structures PS-A, thereby affecting the light extraction efficiency of the light guide plate 100.

[0077] Figure 4 is a cross-sectional view of a display device according to a fourth embodiment of the present invention. Figure 4 , compared to Figure 1 Regarding the front light module FLM, in the display device 10C of this embodiment, the front light module FLM-C may further include multiple hydrophobic layers HS covering the multiple optical surfaces OS of the light guide plate 100. The provision of these hydrophobic layers HS reduces the surface energy of the optical surface OS of the light guide plate 100 relative to the first adhesive layer 121, preventing the first adhesive layer 121 from adhering to the optical surface OS. Furthermore, due to its internal cohesive force, the first adhesive layer 121 is prevented from protruding into the microgrooves MG. This prevents the first adhesive layer 121 from completely filling or covering the multiple microgrooves MG of the light guide plate 100, thereby affecting light extraction efficiency.

[0078] It is particularly noted that the present invention does not limit the cross-sectional profile of the protruding structure. For example, the cross-sectional profile of the protruding structure may be a semicircular (e.g. Figure 2 The raised structure PS), trapezoidal (such as Figure 3 The protruding structure PS-A) or other configurations suitable for preventing the first adhesive layer 121 from penetrating into the micro groove MG.

[0079] Figure 5 is a schematic cross-sectional view of a display device according to a fifth embodiment of the present invention. Figure 6 yes Figure 5 A cross-sectional diagram of part of the manufacturing process of the front light module. Figure 5The display device 10D of this embodiment is Figure 1 The display device 10 of this embodiment differs in that the first adhesive layer 121D of the front light module FLM-D does not extend into the multiple micro-grooves MG of the light guide plate 100. In other words, the ratio of the volume of the multiple gaps G" defined by the first adhesive layer 121D and the light guide plate 100 to the volume of the multiple micro-grooves MG is substantially equal to 1. This ensures that the entire volume of the micro-grooves MG is not occupied by the first adhesive layer 121D, thereby affecting the light extraction efficiency of the light guide plate 100.

[0080] In order to allow the first adhesive layer 121D to be cured outside the plurality of micro grooves MG, after the first adhesive layer 121D contacts the light guide plate 100, a portion of the adhesive layer is first light-cured. Figure 5 and Figure 6 For example, during the light curing process of a portion of the adhesive layer, a microlens array 300 can be disposed between the first adhesive layer 121D and a curing light source (e.g., a UV light source), with the first adhesive layer 121D positioned at the focal length of the microlens array 300. The microlens array 300 includes a plurality of microlenses ML arranged in an array.

[0081] After passing through the multiple microlenses ML of the microlens array 300, the curing light CL is focused on multiple localized areas of the first adhesive layer 121D, forming a plurality of pre-cured, spaced-apart first portions 121p1. The remaining portions of the first adhesive layer 121D (i.e., portions not within the focal length of the microlenses ML) cannot be cured due to insufficient energy from the curing light CL. The entire first adhesive layer 121D must be bonded to the light-transmitting substrate 150 via the second adhesive layer and degassed before the entire first adhesive layer 121D can be cured to form the plurality of second portions 121p2. It is important to note that this entire curing process is performed, for example, without the microlens array 300.

[0082] During the bonding process between the light guide plate 100 and the light-transmitting substrate 150, these pre-cured first parts 121p1 can serve as a supporting structure between the light guide plate 100 and the light-transmitting substrate 150 to prevent the first adhesive layer 121D from penetrating into the multiple micro-grooves MG of the light guide plate 100 and affecting the light extraction efficiency of the light guide plate 100.

[0083] Figure 7 is a schematic cross-sectional view of a display device according to a sixth embodiment of the present invention. Figure 8 is a schematic cross-sectional view of a display device according to a seventh embodiment of the present invention.

[0084] Please refer to Figure 7 The display device 10E of this embodiment is Figure 1The difference between the display devices 10 is the depth of the micro-grooves. For example, in this embodiment, the depth DT of the micro-grooves MG-A of the light guide plate 100A along the normal direction of the surface 150s of the light-transmitting substrate 150 can be significantly greater than the thickness TH of the first adhesive layer 121 along the normal direction of the surface 150s of the light-transmitting substrate 150.

[0085] Preferably, the ratio of the depth DT of the microgrooves MG-A to the thickness TH of the first adhesive layer 121 can be greater than 5.7. Even if the first adhesive layer 121 penetrates into the microgrooves MG-A (i.e., the first adhesive layer 121 has a portion 121p extending into the microgrooves MG-A), it will not substantially affect the optical performance of the optical surface OS.

[0086] In this embodiment, the light guide plate 100A further includes a back surface BS defining microgrooves MG-A and connecting to the optical surface OS. The cross-sectional profiles of the optical surface OS and the back surface BS are substantially equal in length, or the difference in these profile lengths is less than 5%. In other words, the cross-sectional profiles of the microgrooves MG-A in this embodiment are symmetrical.

[0087] However, the present invention is not limited thereto. Figure 8 In another embodiment of the light guide plate 100B, the cross-sectional profile of the micro-grooves MG-B may be asymmetric. That is, the lengths of the cross-sectional profiles of the optical surface OS" and the back surface BS may be different. For example, the length L1 of the cross-sectional profile of the optical surface OS" of the light guide plate 100B may be greater than the length L2 of the cross-sectional profile of the back surface BS. Therefore, even if the first adhesive layer 121 penetrates into the micro-grooves MG-B, the light guide plate 100B can still have sufficient optical surface OS" that is not covered by the first adhesive layer 121 to reflect light. Therefore, in Figure 8 In the embodiment, the depth DT" of the micro groove MG-B may be less than Figure 7 Preferably, the ratio of the depth DT" of the micro-groove MG-B to the thickness TH of the first adhesive layer 121 may be greater than 2 and less than 5.7.

[0088] In summary, in a frontlight module according to one embodiment of the present invention, a light guide plate (LGP) is provided with a plurality of micro-grooves and a light-transmitting substrate on the side facing away from the display panel. An adhesive layer is provided between these micro-grooves and the light-transmitting substrate, and at least a majority of the volume of these micro-grooves is not filled by the adhesive layer. This ensures that the light guide plate is protected while also ensuring efficient light extraction from the LGP.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A front light module, characterized in that: Suitable for being arranged on the display surface of the display panel, the front light module comprises: a light guide plate having a light incident surface, and a first surface and a second surface connected to the light incident surface and opposite to each other, wherein the first surface faces the display surface of the display panel; a light source, disposed on one side of the light incident surface of the light guide plate; a plurality of micro grooves, disposed on the second surface of the light guide plate and recessed from the second surface; a light-transmitting substrate, disposed on one side of the second surface of the light guide plate; and A first adhesive layer is disposed between the light-transmitting substrate and the light guide plate, and connects the light-transmitting substrate and the light guide plate, wherein unfilled portions of the plurality of micro-grooves define a plurality of gaps, and a ratio of the volume of the plurality of gaps to the volume of the plurality of micro-grooves is greater than or equal to 0.9 and less than or equal to 1.

2. The front light module according to claim 1, wherein: Also includes: a cover plate, disposed on a side of the light-transmitting substrate facing away from the first adhesive layer; as well as The second adhesive layer is disposed between the cover plate and the light-transmitting substrate and connects the cover plate and the light-transmitting substrate, wherein the first adhesive layer is different from the second adhesive layer.

3. The front light module according to claim 2, characterized in that: The loss tangent of the viscoelasticity of the first adhesive layer is smaller than the loss tangent of the viscoelasticity of the second adhesive layer.

4. The front light module according to claim 1, wherein: The loss tangent of the viscoelasticity of the first adhesive layer at a temperature of 25 degrees Celsius is greater than or equal to 0.1 and less than or equal to 0.

2.

5. The front light module according to claim 1, wherein: The first adhesive layer has a portion extending into each of the multiple micro-grooves, and the percentage of the orthographic projection area of ​​the portion of the first adhesive layer on a cross-section perpendicular to the light incident surface of the light guide plate and the second surface to the orthographic projection area of ​​each of the multiple micro-grooves on the cross-section is less than or equal to 15%.

6. The front light module according to claim 1, wherein: A plurality of protruding structures are provided on the surface of the light-transmitting substrate facing the light guide plate, and the plurality of protruding structures extend into the plurality of micro-grooves respectively.

7. The front light module according to claim 6, characterized in that: Each of the plurality of protruding structures has a portion extending into a corresponding one of the plurality of micro-grooves, the portion of each of the plurality of protruding structures has a first thickness along a normal direction of the surface, each of the plurality of protruding structures has a second thickness along the normal direction of the surface, and a percentage of the first thickness to the second thickness is less than or equal to 10%.

8. The front light module according to claim 6, wherein: A difference between a refractive index of the plurality of protrusion structures and a refractive index of the first adhesive layer is less than or equal to 0.

15.

9. The front light module according to claim 1, wherein: A plurality of protruding structures are provided on the surface of the light-transmitting substrate facing the light guide plate, the first adhesive layer is located between the plurality of protruding structures, and the orthographic projections of the plurality of micro-grooves on the surface of the light-transmitting substrate are respectively located within the orthographic projections of the plurality of protruding structures on the surface of the light-transmitting substrate.

10. The front light module according to claim 1, wherein: The light guide plate further comprises a plurality of optical surfaces defining the plurality of micro grooves, and the plurality of optical surfaces of the plurality of micro grooves are each covered with a hydrophobic layer.

11. The front light module according to claim 1, wherein: The first adhesive layer has a thickness along the normal direction of the surface of the light-transmitting substrate facing the light guide plate, each of the multiple micro-grooves has a depth along the normal direction of the surface of the light-transmitting substrate, and the ratio of the depth of each of the multiple micro-grooves to the thickness of the first adhesive layer is greater than 5.

7.

12. The front light module according to claim 1, wherein: The cross-sectional profile of each of the plurality of micro grooves is asymmetrical.

13. The front light module according to claim 12, wherein: The light guide plate also has an optical surface defining each of the multiple micro-grooves and a back surface connected to the optical surface, the optical surface faces the light incident surface, the back surface faces away from the light incident surface, and the length of the cross-sectional profile of the optical surface is greater than the length of the cross-sectional profile of the back surface.

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