Light guide plate and method of manufacturing the same

Abstract

A light guide plate and a method of manufacturing the same are provided. The light guide plate includes a first light guide layer and a second light guide layer superimposed on a lower surface of the first light guide layer, the first light guide layer and the second light guide layer configured to guide light as guided light. The first light guide layer includes an array of micro-reflective structures arranged on the lower surface of the first light guide layer configured to reflect a portion of the guided light out toward an upper surface of the first light guide layer, and a reflective layer arranged below the array of micro-reflective structures, each micro-reflective structure of the array of micro-reflective structures forming a closed cavity with a corresponding reflective element of the reflective layer. The second light guide layer covers the reflective layer of the first light guide layer.

Description

Technical Field

[0001] This disclosure relates to the field of displays, and more specifically, to a light guide plate and a method for manufacturing the light guide plate. Background Technology

[0002] A light guide plate is a crucial component of an electronic display, typically located between the front and back panels. It transforms line light sources into surface light sources, resulting in more uniform brightness. Light guide plates are generally made by forming light-guiding points (e.g., an array of micro-reflective structures) on the surface of an optical-grade material, along with reflective sheets. When light strikes these points, the reflected light diffuses in all directions, exiting from the front of the light guide plate. The reflective sheets reflect light exposed on the bottom surface back into the light guide plate, improving light efficiency and thus increasing the display's brightness.

[0003] In traditional light guide plate designs, the light guide points are usually placed in the upper light guide, while the reflector is placed in the lower light guide. Then, the two light guides are bonded together with an adhesive to form the final light guide plate.

[0004] like Figure 1 As shown, an array of light guide points 11 in the form of micro-reflective structures is disposed on the lower surface of the upper light guide 10, and an array of reflective sheets 22 corresponding to each light guide point 11 is disposed on the upper surface of the lower light guide 20. The upper light guide 10 and the lower light guide 20 are bonded together by adhesive 30.

[0005] In this design, aligning and bonding the two light guide layers while maintaining a constant bonding gap presents technological challenges. For example, it is generally desirable to achieve precise alignment between the light guide point 11 in the upper light guide 10 and the corresponding reflective sheet 22 in the lower light guide 20, which requires a high-precision laminator. Furthermore, it is desirable for the gap between the light guide point 11 in the upper light guide 10 and the corresponding reflective sheet 22 in the lower light guide 20 to be constant and sufficiently small. This ensures that when… Figure 1 As shown, when light L propagates in the light guide plate, the probability of it being trapped between the light guide point 11 and the reflector 22 is greatly reduced, thereby effectively improving the overall brightness of the light guide plate. At the same time, the constant gap also helps to reduce moiré fringes. Summary of the Invention

[0006] The present disclosure is made in view of the above problems. In order to achieve accurate alignment between the light guide dots and the reflective sheet, and in order to achieve a constant and sufficiently small gap between the light guide dots and the reflective sheet, the present disclosure proposes arranging both the light guide dots and the reflective sheet in the same light guide layer, for example, in the first light guide layer. At the same time, in order to prevent the reflective sheet from being corroded by being exposed to air, a second light guide layer is attached to the first light guide layer to cover the reflective sheet, playing a dual role of light guiding and protection.

[0007] According to one aspect of the present disclosure, a light guide plate is provided, comprising: a first light guide layer; and a second light guide layer superimposed on a lower surface of the first light guide layer, the first light guide layer and the second light guide layer being configured to guide light as guided light. The first light guide layer comprises: an array of micro-reflective structures arranged on the lower surface of the first light guide layer, configured to reflect a portion of the guided light out towards an upper surface of the first light guide layer; and a reflective layer arranged below the array of micro-reflective structures, one or more micro-reflective structures in the array of micro-reflective structures and a corresponding one or more reflective elements in the reflective layer forming a closed cavity. The second light guide layer covers the reflective layer of the first light guide layer.

[0008] In some embodiments, each micro-reflective structure in the array of micro-reflective structures comprises a conical micro-reflective structure, and an outer surface of the conical micro-reflective structure is configured to reflect a portion of the guided light out towards the upper surface of the first light guide layer.

[0009] In some embodiments, each micro-reflective structure in the array of micro-reflective structures comprises a hemispherical micro-reflective structure, and an outer surface of the hemispherical micro-reflective structure is configured to reflect a portion of the guided light out towards the upper surface of the first light guide layer.

[0010] In some embodiments, each reflective element of the reflective layer has a square shape corresponding to each micro-reflective structure in the array of micro-reflective structures.

[0011] In some embodiments, a minimum gap between a micro-reflective structure in the array of micro-reflective structures and a corresponding reflective element in the reflective layer is 1 um.

[0012] According to another aspect of the present disclosure, a manufacturing method of a light guide plate is provided, comprising: forming an array of micro-reflective structures on a surface of a first light guide layer; arranging a reflective layer on the first light guide layer such that one or more micro-reflective structures in the array of micro-reflective structures and a corresponding one or more reflective elements in the reflective layer form a closed cavity; and bonding a second light guide layer with the first light guide layer such that the second light guide layer covers the reflective layer.

[0013] In some embodiments, the forming the array of micro-reflective structures on the surface of the first light guide layer comprises: arranging a substrate on the surface of the first light guide layer; imprinting a micro-structure pattern on the substrate to form the array of micro-structures; and arranging a reflective material on the surface of the array of micro-structures to form the array of micro-reflective structures.

[0014] In some embodiments, each micro-reflective structure in the array of micro-reflective structures comprises a conical micro-reflective structure or a hemispherical micro-reflective structure.

[0015] In some embodiments, the arranging the reflective layer on the first light guide layer comprises: arranging a photoresist layer on the array of micro-reflective structures; forming a reflective metal layer on the photoresist layer; etching reflective units corresponding to the micro-reflective structures in the array of micro-reflective structures in the reflective metal layer; and edge sealing the micro-reflective structures and the corresponding reflective units, such that one or more micro-reflective structures and the corresponding one or more reflective units form a closed cavity.

[0016] In some embodiments, a minimum gap between each micro-reflective structure in the array of micro-reflective structures and the corresponding reflective unit is 1 um. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A schematic diagram showing the structure of a conventional light guide plate is shown.

[0018] Figure 2 A schematic diagram showing the structure of a light guide plate according to an embodiment of the present disclosure is shown.

[0019] Figures 3A-3D A schematic diagram showing a closed cavity formed by a micro-reflective structure and a corresponding reflective unit according to an embodiment of the present disclosure is shown.

[0020] Figure 4 A flowchart showing a manufacturing method of a light guide plate according to an embodiment of the present disclosure is shown.

[0021] Figures 5A-5C A process flowchart showing a manufacturing method of a light guide plate according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0022] Embodiments of the present disclosure will be described in more detail with reference to the drawings. Although some embodiments of the present disclosure are illustrated in the drawings, it is understood that the present disclosure should not be construed as being limited to the embodiments set forth herein, but rather, the embodiments are provided to more fully understand the present disclosure. It is understood that the drawings and embodiments of the present disclosure are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

[0023] It should be noted that each component or assembly described in various embodiments of the present disclosure is merely illustrative. In some cases, some of them can be omitted, or some of them can be replaced with other components or assemblies with the same or similar functions, or additional components or assemblies can be added.

[0024] In addition, each component or assembly described in various embodiments of the present disclosure is merely for convenience of description, and does not mean that they are physically separated or combined with each other, nor that such separation or combination is necessary. Those skilled in the art can arbitrarily split or combine each component or assembly according to actual needs.

[0025] Any variation or combination described above falls within the scope of protection of the present disclosure without departing from the inventive concept of the present disclosure.

[0026] Embodiments of the present disclosure provide a light guide plate. Figure 2 A schematic diagram showing the structure of a light guide plate 1000 according to an embodiment of the present disclosure is shown.

[0027] As shown in Figure 2 The light guide plate 1000 includes a first light guide layer 110 and a second light guide layer 120 superimposed on the lower surface of the first light guide layer. The first light guide layer 110 and the second light guide layer 120 are configured to guide light (e.g., light from a light source) as guided light.

[0028] For example, the first light guide layer 110 and the second light guide layer 120 can be layers of material capable of guiding light made of silica, acrylic material, etc.

[0029] The first light guide layer 110 includes an array of micro-reflective structures 111 arranged on the lower surface of the first light guide layer 110 and a layer of reflective units 112 collectively formed by a series of reflective units arranged below the array of micro-reflective structures 111. The array of micro-reflective structures 111 is configured to reflect a portion of the guided light in the first light guide layer 110 and the second light guide layer 120 toward the upper surface of the first light guide layer 110 as output light. The second light guide layer 120 is bonded to the lower surface of the first light guide layer 110 by an adhesive 130 and covers the layer of reflective units on the first light guide layer 110, which can protect the layer of reflective units from corrosion such as oxidation caused by exposure.

[0030] In addition, Figure 2The figure also shows an additional reflective unit 112-1 located at the edge of the light guide layer 110, which does not form a closed cavity with any micro-reflective structure, but exists independently at the edge of the light guide layer 110. The additional reflective unit 112-1 arranged at the edge of the light guide layer 110 is to reflect the light leakage at the light source connection during the subsequent installation of the light source, so as to prevent the light source from leaking light, and further improve the overall brightness of the light guide plate or display.

[0031] As shown in the figure, each micro-reflective structure 111 in the array of micro-reflective structures 111 forms a closed cavity with the corresponding reflective unit 112 in the reflective layer. Figures 3A-3D A schematic diagram of a closed cavity formed by a micro-reflective structure and a corresponding reflective unit according to an embodiment of the present disclosure is shown. Among them, Figure 3A and Figure 3B A schematic diagram of a micro-reflective structure including a conical micro-reflective structure is shown, and Figure 3C and Figure 3D A schematic diagram of a micro-reflective structure including a hemispherical micro-reflective structure is shown.

[0032] For example, as Figure 3A shown, each micro-reflective structure in the array of micro-reflective structures can include a conical micro-reflective structure. Figure 3A (a) in FIG. 1 shows a cross-sectional view of a micro-reflective structure including a conical micro-reflective structure forming a closed cavity with a corresponding reflective unit, and Figure 3A (b) in FIG. 1 shows a corresponding top view.

[0033] In the case where each micro-reflective structure in the array of micro-reflective structures as shown in Figure 3A includes a conical micro-reflective structure, for example, the corresponding reflective unit in the reflective layer can have a square shape corresponding to each micro-reflective structure (for example, indicated by the square profile shown in Figure 3A (b)).

[0034] In the case shown in Figure 3A , the outer surface of the conical micro-reflective structure can be configured to reflect a portion of the guided light in the first light guide layer 110 and the second light guide layer 110 out of the upper surface of the first light guide layer 110 as output light.

[0035] Figure 3A An example of a single micro-reflective structure forming a closed cavity with a corresponding single reflective unit is shown. In some embodiments, a closed cavity can also be formed between multiple micro-reflective structures and corresponding multiple reflective units, for example, as shown in the example of Figure 3B .

[0036] Unlike the example shown in Figure 3A , in the case where the array of micro-reflective structures includes a plurality of micro-reflective structures, the corresponding reflective unit in the reflective layer can have a shape corresponding to each micro-reflective structure.Figure 3B In this context, three microreflective structures, each including a conical microreflective structure, and three corresponding consecutive reflective units (e.g., composed of...) can be used. Figure 3B (as indicated by the rectangular outline shown in (b)) is closed, thus forming a larger closed cavity.

[0037] It should be noted that the three micro-reflective structures, including conical micro-reflective structures, and the corresponding three consecutive reflective units forming a closed cavity, as described above, are merely exemplary and not limiting.

[0038] In practical applications, more or fewer micro-reflective structures and corresponding reflective units can be enclosed as needed to form enclosed cavities of different sizes. For example, an entire row or column of micro-reflective structures in the light guide layer can be enclosed with corresponding continuous reflective units to form enclosed cavities corresponding to an entire row or column.

[0039] The above examples illustrate microreflective structures including conical microreflective structures. Microreflective structures of other shapes are also possible. For example, Figure 3C and Figure 3D A schematic diagram of a microreflective structure, including a hemispherical microreflective structure, is shown.

[0040] For example, Figure 3C An example is shown where a single microreflective structure containing a hemispherical microreflective structure forms a closed cavity with its corresponding single reflective unit.

[0041] In such Figure 3C In the case where each microreflective structure shown includes a hemispherical microreflective structure, for example, the corresponding reflective unit in the reflective layer can have a square shape corresponding to each microreflective structure (e.g., by...). Figure 3C (as indicated by the square outline shown in (b)).

[0042] exist Figure 3C In the case shown, the outer surface of the hemispherical micro-reflective structure can be configured to reflect a portion of the light guided in the first light guide layer 110 and the second light guide layer 110 toward the upper surface of the first light guide layer 110 as output light.

[0043] In some other embodiments, for cases involving hemispherical microreflective structures, a closed cavity can be formed between multiple microreflective structures and corresponding multiple reflective units, for example, as shown in the example. Figure 3D The example is shown in the image.

[0044] and Figure 3C The example shown is different in that... Figure 3D For example, three microreflective structures, each including a hemispherical microreflective structure, and three corresponding consecutive reflective units (e.g., made of...) can be used.Figure 3D (b) as indicated by the rectangular profile) to form a larger enclosed cavity.

[0045] It should be noted that the three micro-reflective structures including hemispherical micro-reflective structures and the corresponding three continuous reflective units as described above form an enclosed cavity only as an example and is not limited.

[0046] In practical applications, more or less micro-reflective structures and corresponding reflective units can be enclosed to form different sizes of enclosed cavities as needed. For example, an entire row or column of micro-reflective structures in the light guide layer and the corresponding continuous reflective units can be closed to form an enclosed cavity corresponding to the entire row or column.

[0047] In addition, the above-mentioned micro-reflective structures including conical and hemispherical micro-reflective structures are only illustrative, and other shapes of micro-reflective structures are also possible, including but not limited to various prisms (e.g., 3-prism, 4-prism, 5-prism, etc.), various pyramids (e.g., 3-pyramid, 4-pyramid, 5-pyramid, etc.), and quarter spherical surface, quarter ellipsoidal surface, etc.

[0048] As described above, various micro-reflective structures are usually formed by nano-imprinting technology and plating or sputtering technology. For example, an array of micro-structures can be first imprinted on the first light guide layer by a mold, and then a layer of metal reflective film is formed on the surface of the micro-structure by plating or sputtering technology, thereby forming an array of various micro-reflective structures as described above.

[0049] Similarly, the reflective layer as described above can also be formed by plating or sputtering technology. At the same time, if it is needed to form reflective units of various shapes (e.g., square or rectangular) on the reflective layer, further etching methods can be used to achieve this.

[0050] These details will be described in detail in the following embodiments of the manufacturing method of the light guide plate, and will not be repeated here.

[0051] By arranging the micro-reflective structures and the reflective units in the same light guide layer, it is beneficial to effectively control the size and uniformity of the gap between the two without the need for a high-precision laminator.

[0052] As shown in Figures 3A to 3D The minimum gap d between the micro-reflective structures in the array of micro-reflective structures and the corresponding reflective units in the reflective layer can be as small as 1 um, thereby effectively preventing the guided light in the light guide layer from entering the gap and being trapped in the gap. In addition, the enclosed reflective cavity can effectively reflect and recycle the light irradiated onto the outer surface of the cavity, thereby improving the overall brightness of the light guide plate.

[0053] At the same time, the constant and as small as possible gap d between the micro-reflective structures in the array of micro-reflective structures and the corresponding reflective elements in the reflective layer also helps to eliminate Moiré fringes.

[0054] A specific method for manufacturing the light guide plate as described above will be described below in conjunction with the accompanying drawings. Figure 4 and Figures 5A to 5C A specific method for manufacturing the light guide plate as described above will be described below in conjunction with the accompanying drawings.

[0055] Figure 4 A flow chart of the method 4000 for manufacturing the light guide plate according to an embodiment of the present disclosure is shown. Figures 5A-5C A corresponding process flow chart of the method for manufacturing the light guide plate according to an embodiment of the present disclosure is shown.

[0056] As Figure 4 shown, the method 4000 for manufacturing the light guide plate includes the following steps:

[0057] S4010: forming an array of micro-reflective structures on a surface of a first light guide layer;

[0058] S4020: arranging a reflective layer on the first light guide layer, so that one or more micro-reflective structures in the array of micro-reflective structures form a closed cavity with one or more corresponding reflective elements in the reflective layer; and

[0059] S4030: bonding a second light guide layer with the first light guide layer, so that the second light guide layer covers the reflective layer.

[0060] Figure 5A A process flow chart corresponding to step S4010 is shown. In some embodiments, forming an array of micro-reflective structures on a surface of a first light guide layer can include the following detailed processes.

[0061] First, a substrate S can be arranged on a surface of the first light guide layer 110. For example, the substrate S can be a material of acrylic or plexiglass, such as polymethyl methacrylate (PMMA).

[0062] Then, a microstructure pattern on a mold can be imprinted onto the substrate S to form an array of microstructures. For example, the mold can be made of silicon or silicon dioxide, and has any one of various microstructure patterns, including but not limited to a conical microstructure, a hemispherical microstructure, a prismatic microstructure, or a pyramidal microstructure, etc.

[0063] Next, after the array of microstructures is formed on the substrate S, a reflective material can be further arranged on a surface of the array of microstructures, thereby forming an array of micro-reflective structures. For example, various plating or sputtering techniques can be used to arrange a reflective film of, for example, silver, aluminum, or various alloy materials on the surface of the array of microstructures, thereby forming an array of micro-reflective structures 111 as shown. Figure 5A ​

[0064] Figure 5B A process flow chart corresponding to step S4020 is shown. For example, in some embodiments, disposing a reflective layer on the first light guide layer can include the following detailed process.

[0065] First, a photoresist layer PR is disposed on the array of micro-reflective structures formed in step S4010. For example, in the case where the micro-reflective structures include conical micro-reflective structures, the photoresist can be filled within each cone to a certain thickness, such that the photoresist covers each micro-reflective structure.

[0066] In this step, the thickness of the photoresist layer needs to be controlled, and in turn the gap or distance between the micro-reflective structures and the subsequent reflective units is controlled. For example, the thickness of the photoresist layer can be controlled to be within 1 um, so as to ensure that the minimum gap between each micro-reflective structure in the array of micro-reflective structures and the corresponding reflective unit is 1 um.

[0067] Then, a reflective metal layer can be formed on the photoresist layer PR. For example, the way of forming the reflective metal layer includes but is not limited to vacuum thermal evaporation, electron beam evaporation, magnetron sputtering, plasma chemical vapor deposition, etc. The thickness of the reflective metal layer is preferably in the range of 200-240 nm. For example, the material of the reflective metal layer can be aluminum (Al) or silver (Ag) or silver alloy. The reflective metal layer can reflect the light incident thereon back, thereby reducing light loss and in turn increasing the brightness of the display.

[0068] Then, the reflective units corresponding to the micro-reflective structures in the array of micro-reflective structures can be etched in the reflective metal layer. For example, in the case where a single micro-reflective structure corresponds to a single reflective unit, a square reflective unit corresponding to the size of the micro-reflective structure can be etched. In addition, for example, in the case where multiple micro-reflective structures correspond to multiple reflective units, multiple continuous reflective units corresponding to the size of the multiple micro-reflective structures can be etched.

[0069] After the corresponding reflective units are etched, the micro-reflective structures and the corresponding reflective units are edge-sealed, so that the micro-reflective structures and the corresponding reflective units form a closed cavity. For example, in the case where a single micro-reflective structure corresponds to a single reflective unit, the edges of the micro-reflective structure and the corresponding reflective unit can be bonded with a reflective material, so that the single micro-reflective structure and the single reflective unit form a closed cavity. In addition, for example, in the case where multiple micro-reflective structures correspond to multiple reflective units, the edges of the multiple micro-reflective structures and the corresponding multiple continuous reflective units can be bonded with a reflective material, so that the multiple micro-reflective structures and the multiple reflective units form a closed cavity.

[0070] In addition, Figure 5BThe figure additionally shows a reflective unit 112-1 located at the edge of the light guide layer 110, which does not form a closed cavity with any micro-reflective structure, but exists independently at the edge of the light guide layer 110. The additional reflective unit 112-1 is arranged at the edge of the light guide layer 110 to reflect the light leakage at the connection of the light source during the subsequent installation process of the light source, so as to prevent the light leakage of the light source and further improve the overall brightness of the light guide plate or the display.

[0071] Figure 5C A process flow chart corresponding to step S4030 is shown. After the arrangement of the array of micro-reflective structures and the arrangement of the reflective layer are completed, the second light guide layer is combined to the lower surface of the first light guide layer 110 by the adhesive 130, so that the second light guide layer 120 covers the reflective layer, thereby preventing the reflective layer from being exposed to the air and corroded.

[0072] It should be noted that various other details and additional technical features of the embodiments of the light guide plate described above with respect to Figures 1 to 3D are equally applicable to the manufacturing method of the light guide plate of Figures 4 to 5C unless otherwise stated in the text or obviously not applicable according to the context.

[0073] Similarly, various other details and additional technical features of the embodiments of the manufacturing method of the light guide plate described above with respect to Figures 4 to 5C are equally applicable to the various embodiments of the light guide plate of Figures 1 to 3D unless otherwise stated in the text or obviously not applicable according to the context

[0074] In the above description, embodiments of the present disclosure have been described in conjunction with the accompanying drawings. It should be understood that the above-described embodiments are merely illustrative, and those skilled in the art should understand that the combination of constituent elements and processes of the present embodiments can be modified in various ways, and such modifications also fall within the scope of the present disclosure.

Claims

1. A light guide plate, comprising: First optical guide layer; as well as A second optical guide layer superimposed on the lower surface of the first optical guide layer. The first and second light-guiding layers are configured to guide light as the guided light. The first optical guide layer includes: An array of microreflective structures disposed on the lower surface of the first light guide layer is configured to reflect a portion of the guided light toward the upper surface of the first light guide layer; and A reflective layer is arranged below the array of microreflective structures, wherein one or more microreflective structures in the array of microreflective structures and one or more corresponding reflective elements in the reflective layer form a closed cavity, and The second optical guide layer covers the reflective layer of the first optical guide layer.

2. The light guide plate according to claim 1, wherein, Each microreflective structure in the array of microreflective structures includes a conical microreflective structure, and the outer surface of the conical microreflective structure is configured to reflect a portion of the guided light toward the upper surface of the first light guide layer.

3. The light guide plate according to claim 1, wherein, Each microreflective structure in the array of microreflective structures includes a hemispherical microreflective structure, and the outer surface of the hemispherical microreflective structure is configured to reflect a portion of the guided light toward the upper surface of the first light guide layer.

4. The light guide plate according to any one of claims 1 to 3, wherein each reflective unit of the reflective layer has a square shape corresponding to each microreflective structure in the array of microreflective structures.

5. The light guide plate according to claim 1, wherein the minimum gap between the micro-reflection structure in the array of micro-reflection structures and the corresponding reflection unit in the reflection layer is 1 μm.

6. A method for manufacturing a light guide plate, comprising: An array of micro-reflective structures is formed on the surface of the first optical guide layer; A reflective layer is arranged on the first optical guide layer, such that one or more micro-reflective structures in the array of micro-reflective structures and one or more corresponding reflective units in the reflective layer form a closed cavity; as well as The second light guide layer is bonded to the first light guide layer so that the second light guide layer covers the reflective layer.

7. The method according to claim 6, wherein, The array of micro-reflective structures formed on the surface of the first optical guide layer includes: A substrate is disposed on the surface of the first optical guide layer; The microstructure pattern on the mold is imprinted onto the substrate to form an array of microstructures; and A reflective material is arranged on the surface of the array of microstructures to form the array of microreflective structures.

8. The method according to claim 6 or 7, wherein, Each microreflective structure in the array of microreflective structures includes a conical microreflective structure or a hemispherical microreflective structure.

9. The method according to claim 7, wherein, The step of arranging a reflective layer on the first optical guide layer includes: A photoresist layer is disposed on the array of the microreflective structures; A reflective metal layer is formed on the photoresist layer; Reflective elements corresponding to the micro-reflective structures in the array of micro-reflective structures are etched into the reflective metal layer; and The micro-reflective structure and the corresponding reflective unit are edge-sealed so that one or more micro-reflective structures and one or more corresponding reflective units form a closed cavity.

10. The method according to claim 6, wherein the minimum gap between each microreflective structure in the array of microreflective structures and its corresponding reflective unit is 1 μm.

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