Front light guide plate and electronic paper display device

Abstract

The utility model relates to the technical field of display, in particular to a front light guide plate and an electronic paper display device. The front light guide plate is applied to the electronic paper display device comprising an electronic paper display panel, and comprises a light incident surface which is located at the side part of the extending direction of the front light guide plate; the second main surface is located on one side of the front light guide plate in the thickness direction and provided with an adjacent area adjacent to the light incident surface, and the second main surface faces the electronic paper display panel; and the plurality of second light guide microstructures are arranged in the adjacent area of the second main surface, and the plurality of second light guide microstructures are discrete microstructures which are separated from one another.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a front light guide plate and an electronic paper display device. BACKGROUND

[0002] Electronic paper display (EPD) is a reflective display technology, which has the advantages of low power consumption, bistability, wide viewing angle, high contrast under strong light, lightness, portability, eye protection, etc. and has been widely applied to various fields such as shelf label, reader, smart medical care, smart office, outdoor display, etc. The working principle of EPD is to display images and text by moving small charged white and black particles under the action of electric field. Due to its excellent reading experience and low power consumption, EPD has become the mainstream technology in the e-book reading market.

[0003] Compared with the traditional transmissive liquid crystal display panel, since EPD is a reflective display, it can realize display by reflecting external ambient light, so its screen has better visibility under direct sunlight; but its visibility is greatly reduced in dark background. In order to solve the visibility of EPD in dark background, a front light source, i.e. a front light guide plate, is usually added to provide illumination.

[0004] In order to overcome the interface reflection of the front light guide plate and the EPD and ensure the display effect, the front light guide plate needs to be attached to the EPD by full attachment. However, since the front light guide plate and the EPD are attached together by OCA glue, the interface effect between the front light guide plate and the EPD is weakened or even eliminated, which changes the propagation rule and effect of light in the front light guide plate. Therefore, the front light guide plate originally having uniform distribution of outcoming light intensity will have a dark band parallel to the light entrance surface and penetrating through the entire screen after full attachment, which affects the display effect.

[0005] At present, the problem of the penetrating dark band of EPD is a common problem in the industry. The method commonly used at present is to increase the microstructure density of the front light guide plate at the light entrance to improve the brightness of the front light guide plate at the position where the dark band appears after attachment, so as to compensate for the problem of the penetrating dark band caused by attachment. Although this method can alleviate the width and strength of the dark band after attachment to a certain extent, it cannot completely eliminate or say the alleviation is limited. Therefore, the currently marketed products will have an entrance dark band to a greater or lesser extent, which affects the display effect. This has become one of the factors for consumers to consider when choosing the product. SUMMARY

[0006] In order to solve at least one of the above problems, the present application provides a front light guide plate and an electronic paper display device.

[0007] In a first aspect, a front light guide plate is provided, which is applied to an electronic paper display device including an electronic paper display panel, and includes:

[0008] a light-in surface located at a side of the front light guide plate in an extension direction of the front light guide plate;

[0009] a second main surface located at one side of the front light guide plate in a thickness direction and having an abutment region abutting the light-in surface, the second main surface facing the electronic paper display panel;

[0010] a plurality of second light guide microstructures provided in the abutment region of the second main surface, and the plurality of second light guide microstructures are discrete microstructures spaced apart from each other.

[0011] In some possible embodiments, the second light guide microstructures are configured to guide a second light ray incident on the second light guide microstructures to exit from a second region of the second main surface, the second region being a region abutting the light-in surface.

[0012] In some possible embodiments, the second light ray is a light ray directly from the light-in surface.

[0013] In some possible embodiments, among all light rays directly from the light-in surface and incident on the second light guide microstructures, the intensity proportion of the second light ray is not less than 10%.

[0014] In some possible embodiments, assuming that the abutment region is a flat surface without the second light guide microstructures, the second light ray would be totally reflected in the abutment region to be incident on the first main surface, and eventually exit from a third region of the first main surface or from a fourth region of the second main surface, wherein the third region is a region spaced apart from the light-in surface by at least 6 mm, and the fourth region is a region farther away from the light-in surface than the second region.

[0015] In some possible embodiments, the front light guide plate further includes a first main surface located at the other side of the front light guide plate in the thickness direction;

[0016] The second light ray exiting from the second region returns to the front light guide plate via reflection of the electronic paper display panel, and exits from a first region of the first main surface, the first region being a region abutting the light-in surface.

[0017] In some possible implementations, the second light rays emitted from the second region of the second major surface, after being reflected by the electronic paper display panel, return to the front light guide plate and are emitted from the first region of the first major surface in a manner that does not produce total reflection within the front light guide plate, the first region being a region contiguous with the light-in surface.

[0018] In some possible implementations, the second light rays emitted from the second region of the second major surface, after being reflected by the electronic paper display panel, return to the front light guide plate via the corresponding second light guide microstructures and are emitted from the first region of the first major surface based on the guidance of the corresponding second light guide microstructures.

[0019] In some possible implementations, a width of each of the contiguous region, the first region and the second region in a first direction is no more than 15 mm, wherein the first direction is a direction perpendicular to a second direction and the thickness direction, and the second direction is a direction parallel to the light-in surface and perpendicular to the thickness direction.

[0020] In some possible implementations, a width of each of the contiguous region and the second region in a first direction is no more than 15 mm, wherein the first direction is a direction perpendicular to a second direction and the thickness direction, and the second direction is a direction parallel to the light-in surface and perpendicular to the thickness direction.

[0021] In some possible implementations, a width of each of the contiguous region and the second region in a first direction is no more than 1 / 10 of a size of the front light guide plate in the first direction, wherein the first direction is a direction perpendicular to a second direction and the thickness direction, and the second direction is a direction parallel to the light-in surface and perpendicular to the thickness direction.

[0022] In some possible implementations, an area coverage ratio of the second light guide microstructures in the contiguous region is 0.5% to 8%.

[0023] In some possible implementations, the area coverage ratio of the second light guide microstructures in the contiguous region varies according to a distance to the light-in surface.

[0024] In some possible implementations, the first major surface further comprises a first light guide microstructure.

[0025] The second light guide microstructure is configured to guide the first light rays incident on the second light guide microstructure to the first region of the first major surface and emit the first light rays from the first region, the first region being a region contiguous with the light-in surface.

[0026] In some possible implementation manners, the first light ray will be totally reflected in the abutment region to the first major surface under the assumption that the abutment region is a flat surface without the second light guide microstructure, and finally exits from the third region of the first major surface or from the fourth region of the second major surface, wherein the third region is a region farther away from the light-incident surface than the first region, and the fourth region is a region farther away from the light-incident surface than the second region.

[0027] In some possible implementation manners, the second light ray is a light ray directly from the light-incident surface.

[0028] In some possible implementation manners, the intensity proportion of the second light ray in all light rays directly from the light-incident surface and incident on the second light guide microstructure is not less than 10%.

[0029] In some possible implementation manners, the width of each of the abutment region and the first region in the first direction is not more than 15 mm, wherein the first direction is a direction perpendicular to a second direction and the thickness direction, and the second direction is a direction parallel to the light-incident surface and perpendicular to the thickness direction.

[0030] In a second aspect, an electronic paper display device is provided, which includes:

[0031] The front light guide plate as described in the first aspect;

[0032] The electronic paper display panel;

[0033] The light source is configured on the light-incident surface side.

[0034] The front light guide plate provided in the present application helps to eliminate or alleviate the through-type dark bands appearing at the light-incident port of the electronic paper display device. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present application, but not limit the present application.

[0036] Figure 1 FIG. 1 is a structural schematic diagram of an electronic paper display device provided by the embodiments of the present application, in which the broken lines are represented by double short dashes lines.

[0037] Figure 2 FIG. 2 is a structural schematic diagram of an electronic paper display device provided by the comparative example of the present application, in which the broken lines are represented by double short dash lines.

[0038] Figure 3is a front light guide plate structure schematic diagram provided by an embodiment of the present application.

[0039] Figure 4 is a front light guide plate structure schematic diagram provided by an embodiment of the present application.

[0040] Figure 5 is a second light guide microstructure three-dimensional shape schematic diagram provided by an embodiment of the present application.

[0041] Figure 6 is a second light guide microstructure cross-sectional shape schematic diagram provided by an embodiment of the present application.

[0042] Figure 7 is a second light guide microstructure arrangement schematic diagram provided by an embodiment of the present application.

[0043] Figure 8 is a second light guide microstructure arrangement schematic diagram provided by an embodiment of the present application.

[0044] Figure 9 is a second light guide microstructure arrangement schematic diagram provided by an embodiment of the present application.

[0045] Figure 10 is a second light guide microstructure arrangement schematic diagram provided by an embodiment of the present application.

[0046] Figure 11 is a second light guide microstructure arrangement schematic diagram provided by an embodiment of the present application.

[0047] Figure 12 The area duty cycle of the first light guide microstructure and the second light guide microstructure provided by an embodiment of the present application is shown in a curve diagram.

[0048] Figure 13 The area duty cycle of the first light guide microstructure and the second light guide microstructure provided by an embodiment of the present application is shown in a curve diagram.

[0049] Figure 14 is a light intensity curve of a plurality of configurations of front light modules at different positions from the light inlet surface provided by an embodiment of the present application.

[0050] Figure 15 is Figure 14 The light intensity distribution simulation diagram corresponding to the "With Cover" curve in FIG. 11.

[0051] Figure 16 is Figure 14 The light intensity distribution simulation diagram corresponding to the "Adding dots D=8.5mm" curve in FIG. 12.

[0052] Figure 17 is a display effect photo of an electronic paper display device provided by an embodiment of the present application.

[0053] Figure 18 is a display effect photo of the electronic paper display device provided by the comparative example.

[0054] Explanation of reference signs:

[0055] 1000 - electronic paper display device;

[0056] 100 - light source, 200 - electronic paper display panel, 300 - front light guide plate, 400 - light-transmissive cover plate, 500 - first OCA adhesive layer, 600 - second OCA adhesive layer;

[0057] DR1 - first direction, DR2 - second direction, DR3 - thickness direction;

[0058] 1 - first major surface, 1A - first region, 1B - third region;

[0059] 2 - second major surface, 2A - abutment region, 2B - second region, 2C - fourth region;

[0060] 3 - light-incident surface;

[0061] 4 - first light-guiding microstructure;

[0062] 5 - second light-guiding microstructure;

[0063] Lt1 - first light ray, Lt2 - second light ray. DETAILED DESCRIPTION

[0064] For the purpose of clarity, technical solutions and advantages of the present application will be described below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. It can be understood that some technical means of the various embodiments described herein can be mutually replaced or combined without conflict.

[0065] In the description of the present application, if there are terms such as "first", "second", etc., they are only used to distinguish the described objects, and do not have any order or technical meaning. Therefore, the objects defined with "first", "second", etc. can be explicitly or implicitly include one or more of the objects, and for example, the term "first element" itself does not mean the existence of "second element", and the term "second element" itself does not mean the existence of "first element". In addition, "one" or "an" and the like do not represent a quantity limitation, but represent the existence of at least one, and "multiple" represents no less than two.

[0066] In the description in the present application, the terms "comprising", "having", indicate the presence of the described features, numbers, operations, elements and / or combinations thereof, but do not exclude the presence or addition of one or more other features, numbers, operations, elements and / or combinations thereof.

[0067] In the description in the present application, if there are similar terms such as "configured to" or "structured to", depending on the context, it can be generally interchangeable with "have the ability of", "designed to", "for" or "capable of".

[0068] In the description in the present application, reference to "one embodiment" or "some embodiments" and the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrases "in one embodiment", "in some embodiments", "in other embodiments", "in additional embodiments" and so on, in various places in the specification are not necessarily all referring to the same embodiment, unless otherwise specifically stated. Rather, they are used as a device to connect features, structures or characteristics of one or more embodiments to one or more of the other embodiments.

[0069] Please refer to Figure 1 The electronic paper display device 1000 provided by the embodiments of the present application comprises a light source 100, an electronic paper display panel 200, a front light guide plate 300 and a light-transmitting cover plate 400, wherein the electronic paper display panel 200, the front light guide plate 300 and the light-transmitting cover plate 400 are sequentially stacked, and the first OCA adhesive layer 500 adheres the light-transmitting cover plate 400 to the front light guide plate 300, and the second OCA adhesive layer 600 adheres the front light guide plate 300 to the electronic paper display panel 200. It should be understood that the electronic paper display panel 200 is a reflective display panel.

[0070] The front light guide plate 300 comprises a first major surface 1 and a second major surface 2 opposite in the thickness direction DR3 thereof, and a light-incident surface 3 connecting the first major surface 1 and the second major surface 2, wherein the light-incident surface 3 is located at the side of the extension direction of the front light guide plate 300 and is one of the four side surfaces of the front light guide plate 300. The second major surface 2 is arranged to face the electronic paper display panel 200, and in contrast, the first major surface 1 is arranged to face away from the electronic paper display panel 200 and towards the light-transmitting cover plate 400. Moreover, the first major surface 1 is provided with a plurality of first light guide microstructures 4, which are used to destroy the total reflection condition and change the propagation direction of light rays, so as to make the light rays exit from the second major surface 2 as much as possible and the intensity distribution of the exiting light rays more uniform.

[0071] The second major surface 2 has an abutment region 2A abutting the light-incident surface 3, and a plurality of second light guide microstructures 5 are arranged in the abutment region 2A. Please refer to Figure 1The second light guide microstructure 5 is configured to guide the first light rays Lt1, which are incident on the second light guide microstructure 5, to the first region 1A of the first major surface 1 and out of the first region 1A, and to guide the second light rays Lt2, which are incident on the second light guide microstructure 5, to out of the second region 2B of the second major surface 2, wherein the first region 1A and the second region 2B are both regions adjacent to the light-incident surface 3, and the first light rays Lt1 and the second light rays Lt2 are light rays directly from the light-incident surface 3. It should be understood that the "light rays directly from the light-incident surface 3" as used herein is relative to the second light guide microstructure 5 receiving the light rays, and means light rays entering from the light-incident surface 3 and directly incident on the second light guide microstructure 5 in a straight line direction.

[0072] The light source 100 is arranged at the light-incident surface 3 side of the front light guide plate 300, so as to become a side-in type light source 100. In some embodiments, the light source 100 can include a plurality of LED lamp beads, which are uniformly arranged along the length direction of the light-incident surface 3. In addition, the combination of the front light guide plate 300 and the light source 100 can be referred to as a front light module.

[0073] In operation, after a large number of light rays emitted by the light source 100 enter the front light guide plate 300 via the light-incident surface 3, most of the light rays are emitted downward from the second major surface 2 to the electronic paper display panel 200, are folded back to the front light guide plate 300 via reflection of the electronic paper display panel 200, and are emitted from the first major surface 1 of the front light guide plate 300 to the observer's glasses, so that the observer can observe the picture (e.g., text) displayed by the electronic paper display panel 200.

[0074] More specifically, for the light rays entering the front light guide plate 300 from the light-incident surface 3, a portion is directly incident on the first major surface 1 (including the first light guide microstructures 4 on the first major surface 1), another portion is directly incident on the second major surface 2, and still another portion is directly incident on other parts of the front light guide plate 300, such as the other three side surfaces of the front light guide plate 300 except the light-incident surface 3. And, among the portion of the light rays directly incident on the second major surface 2, a portion is directly incident on the second light guide microstructures 5 of the adjoining area 2A, and another portion is directly incident on positions other than the second light guide microstructures 5, such as the spaced-apart positions between the adjacent two second light guide microstructures 5 in the adjoining area 2A. Further, for the portion of the light rays directly incident on the second light guide microstructures 5, at least include the aforementioned first light rays Lt1 and second light rays Lt2. For the first light rays Lt1, the second light guide microstructures 5 guide them to the first area 1A of the first major surface 1 and out of the first area 1A. And for the second light rays Lt2, the second light guide microstructures 5 guide them to out of the second area 2B of the second major surface 2. Since both the first area 1A and the second area 2B are the areas adjoining the light-incident surface 3, the first light rays Lt1 out of the first area 1A increases the light output (or light intensity) of the first major surface 1 near the light-incident surface 3, thus helping to eliminate or alleviate the dark band of the electronic paper display device 1000 at the light-incident port. And the second light rays Lt2 out of the second area 2B will be incident on the area of the electronic paper display panel 200 adjoining the light-incident surface 3, and after being reflected by the area and returned to the front light guide plate 300, there is a very high possibility that they will be out of the area of the first major surface 1 adjoining the light-incident surface 3, such as the first area 1A, such as in the Figure 1 In the front light guide plate 300, the second light rays Lt2 out of the second area 2B of the second major surface 2, after being reflected by the electronic paper display panel 200, return to the front light guide plate 300 and are out of the first area 1A of the first major surface 1, so the second light rays Lt2 out of the first area 1A also increase the light output of the first major surface 1 near the light-incident surface 3, thus helping to further eliminate or alleviate the dark band of the electronic paper display device 1000 at the light-incident port.

[0075] For comparison, please see Figure 2 In the case of assuming that the adjoining area 2A is a flat surface without the aforementioned plurality of second light guide microstructures 5, the aforementioned first light rays Lt1 and second light rays Lt2 from the light-incident surface 3 will be totally reflected in the adjoining area 2A and be incident on the first major surface 1, and finally out of the third area 1B of the first major surface 1 or out of the fourth area 2C of the second major surface 2 (see the dashed arrows in the figure), wherein the third area 1B is an area further away from the light-incident surface 3 than the first area 1A, and the fourth area 2C is an area further away from the light-incident surface 3 than the second area 2B. It can be seen that, compared with Figure 2Compared with the design shown in the figure, the embodiment increases the light output of the front light guide plate 300 near the light inlet face 3 by arranging the second light guide microstructure 5 in the abutment area 2A, thereby helping to eliminate or alleviate the dark band at the light inlet of the electronic paper display device 1000.

[0076] Since the second area 2B and the abutment area 2A are both areas of the second major surface 2 and both are abutment areas 2A with the light inlet face 3, the second area 2B and the abutment area 2A at least partially overlap, i.e., they at least have a common part. Generally, the second area 2B and the abutment area 2A are substantially completely overlapping the same area. In order to more easily illustrate the present technology, the non-overlapping part of the second area 2B and the abutment area 2A is intentionally exaggerated in Figure 1

[0077] Referring to the foregoing description, for the light rays directly incident on the second light guide microstructure 5, generally only a part of the light rays will become the aforementioned first light rays Lt1 and second light rays Lt2, and another part of the light rays can be guided by the second light guide microstructure 5 to other positions, such as positions away from the aforementioned first area 1A and second area 2B. Therefore, by optimizing the shape of the second light guide microstructure 5, the intensity proportion of the first light rays Lt1 and second light rays Lt2 in all light rays directly from the light inlet face 3 and incident on the second light guide microstructure 5 can be not less than 20% (such as the intensity proportion of each of the first light rays Lt1 and second light rays Lt2 is not less than 10%), and the proportion can be further preferably not less than 40%, thereby significantly increasing the light output of the front light guide plate 300 near the light inlet face 3. In other words, compared with the total energy of the light rays directly from the light inlet face 3 and incident on the second light guide microstructure 5, the sum of the energy of the first light rays Lt1 and second light rays Lt2 can be at least 20%, and more preferably at least 40%.

[0078] The reflectivity of the electronic paper display panel 200 is generally low, and the reflection of the electronic paper display panel 200 can be considered as diffuse reflection, i.e., mainly Lambertian reflection, and also contains part of specular reflection, therefore, the aforementioned second light rays Lt2 emitted from the second area 2B are generally only a part (such as 2%~20%) of the second light rays Lt2 that are reflected by the reflection of the electronic paper display panel 200 to the position where the through dark band appears in the electronic paper display device 1000.

[0079] Those skilled in the art can know that by reasonably configuring the angle of the light-incident face (such as the left side surface of the second light guide microstructure 5) of the second light guide microstructure 5 to the first light rays Lt1 and second light rays Lt2, the aforementioned guidance of the second light guide microstructure 5 to the first light rays Lt1 and second light rays Lt2 can be achieved. Figure 1

[0080] Although in the embodiment, the second light guide microstructure 5 is arranged in the abutment area 2A, it should be understood that the second light guide microstructure 5 can also be arranged in other positions of the second area 2B, such as the position shown in the figure. Figure 1 ​​The first light ray Lt1 and the second light ray Lt2 are shown as two light rays having different angles, but it should be understood that the first light ray Lt1 and the second light ray Lt2 can also be the same light ray, i.e. the second light guide microstructure 5 can direct a portion of the light ray it receives in the beam of light to the first region 1A and directly out of the first region 1A Figure 1 The first light ray Lt1 is guided in its path and another portion of the beam of light is guided in the path of the second light ray Lt2 because the beam of light can both reflect and refract upon contacting the second light guide microstructure 5. Figure 1 The first light ray Lt1 is guided in its path and another portion of the beam of light is guided in the path of the second light ray Lt2 because the beam of light can both reflect and refract upon contacting the second light guide microstructure 5.

[0081] Recall that Figure 1 In some embodiments, the second light guide microstructure 5 is configured to direct the first light ray Lt1 to the first region 1A and directly out of the first region 1A. Figure 1 In some embodiments, the second light guide microstructure 5 is configured to direct the first light ray Lt1 to the first region 1A and directly out of the first region 1A. Figure 1 In some embodiments, the second light guide microstructure 5 is configured to direct the first light ray Lt1 to the first region 1A and directly out of the first region 1A.

[0082] In some embodiments, the second light guide microstructure 5 is configured to direct the first light ray Lt1 to the first region 1A and directly out of the first region 1A.

[0083] In some embodiments, the second light guide microstructure 5 is configured to direct the first light ray Lt1 to the first region 1A and directly out of the first region 1A. Figure 1 .

[0084] In some embodiments, the second light ray Lt2 emitted from the second region 2B of the second main surface 2 is reflected by the electronic paper display panel 200 and returns to the front light guide plate 300 via the corresponding second light guide microstructure 5, and is emitted from the first region 1A of the first main surface 1 based on the guidance of the corresponding second light guide microstructure 5. It is understood that the second light guide microstructure 5 that guides the second light ray Lt2 from the second region 2B of the second main surface 2 and the second light guide microstructure 5 that guides the reflection of the electronic paper display panel 200 into the front light guide plate 300 can be two different second light guide microstructures 5, or they can be the same second light guide microstructure 5.

[0085] For ease of explanation, the direction parallel to the incident light surface 3 and perpendicular to the aforementioned thickness direction DR3 is defined as the second direction DR2, and the direction perpendicular to the second direction DR2 and the aforementioned thickness direction DR3 is defined as the first direction DR1.

[0086] The width D of the aforementioned adjacent region 2A along the first direction DR1 can be 4 mm, meaning that a second light-guiding microstructure 5 is provided at least within a range of 4 mm from the light-incident surface 3. Obviously, this does not preclude the possibility of arranging additional second light-guiding microstructures 5 within a range of 4 mm to 5 mm from the light-incident surface 3. Generally, the width of each of the adjacent region 2A, the first region 1A, and the second region 2B along the first direction DR1 does not exceed 15 mm (e.g., not exceeding 5 mm or 10 mm), meaning that a second light-guiding microstructure 5 must be provided at least within a range of 15 mm from the light-incident surface 3, and the guided first light ray Lt1 and second light ray Lt2 must exit from within a range of 15 mm from the light-incident surface 3. It is understood that when the width of the first region 1A is 6 mm, the distance between the third region 1B and the light-incident surface 3 is not less than (e.g., equal to) 6 mm.

[0087] On the other hand, the width of each of the adjacent regions 2A, the first region 1A, and the second region 2B along the first direction DR1 generally does not exceed 1 / 10 of the size of the front light guide plate 300 along the first direction DR1.

[0088] Furthermore, the length of each of the adjacent region 2A, the first region 1A, and the second region 2B along the second direction DR2 is not less than 9 / 10 of the length of the front light guide plate 300 along the second direction DR2, thereby better suppressing the entire dark band around the light incident surface 3.

[0089] It can be understood that, in the case where the width D of the abutment region 2A along the first direction DR1 is 10 mm, it does not mean that the second light guide microstructures 5 must be arranged in the range of 10 mm, and it also includes the case where no second light guide microstructure 5 is arranged (blank) in the range of 0-3 mm from the light-incident surface 3, and a plurality of second light guide microstructures 5 are arranged relatively densely in the range of 3-10 mm from the light-incident surface 3.

[0090] Generally, the divergence angle of the light source 100 is about 60° (full angle 120°), and the front light guide plate 300 is made of PC substrate with a thickness of 0.25 mm, so the divergence angle of the light rays coupled into (refracted into) the front light guide plate from the light source 100 is 33.2° (full angle 66.4°), and thus the maximum incident angle of the light rays to the second major surface 2 is generally 56.8° (cannot reach 90°), and among the light rays incident to the second major surface 2, the distance closest to the light-incident surface 3 is about 0.2 mm, so it is ineffective to arrange light guide microstructures in the range of 0-0.2 mm because no light rays can be incident thereto. Therefore, in practice, no light guide microstructure can be arranged on the second major surface 2 in the small range closest to the light-incident surface, for example, in the range of 0-1 mm.

[0091] The second light guide microstructures 5 can be recessed microstructures recessed from the second major surface 2, for example Figure 1 and Figure 3 ; or can be protruding microstructures protruding from the second major surface 2, for example Figure 4 . Furthermore, the shapes of the plurality of second light guide microstructures 5 on the second major surface 2 can be the same or different. In addition, the three-dimensional shape of the second light guide microstructures 5 can adopt any one or more of Figure 5 , and the cross-sectional shape of the second light guide microstructures 5 can adopt any one or more of Figure 6 . Furthermore, since those skilled in the art with knowledge of optics have the ability to select more specific configurations of the second light guide microstructures 5 on the basis of the disclosure of the present application, the present embodiment will not be further introduced.

[0092] Furthermore, the plurality of second light guide microstructures 5 can be formed as discrete microstructures (or island microstructures) spaced apart from each other, which helps to make the light emitted from the first major surface 1, particularly the first region 1A, more uniform. It should be understood that the discrete microstructures can also be referred to as dot microstructures (or light guide dots), which are different from the long and narrow strip-shaped microstructures (for example, continuously extending elongated recessed lines or elongated prisms with a length-width ratio exceeding 15, lenti).

[0093] In some embodiments, for a plurality of second light-guiding microstructures 5 disposed in an adjacent region 2A of the second main surface 2, at least a portion of the second microstructures are configured to guide light from the incident light surface 3 in a manner that allows light to pass through the incident light surface 3. Figure 1 The first ray Lt1 is guided in a manner corresponding to the first ray, and the ray from the incident surface 3 is also guided. Figure 1 The second ray Lt2 is guided in a manner corresponding to the second ray; however, another part of the second microstructure can only guide the ray from the incident surface 3. Figure 1 The first ray Lt1 is guided in a manner corresponding to the first ray, but the ray from the incident surface 3 cannot be guided in a manner corresponding to the first ray Lt1. Figure 1 The second ray Lt2 is guided in a manner corresponding to the second ray; another part of the second microstructure can only guide the ray from the incident surface 3. Figure 1 The second ray Lt2 is guided in a manner corresponding to the light source, but the light from the incident surface 3 cannot be guided in the same way. Figure 1 The first ray Lt1 is guided in the same way.

[0094] As some examples Figures 7 to 11 The arrangement of multiple second light-guiding microstructures 5 on the second main surface 2 is shown. Figure 7 In this process, each of the second light-guiding microstructures 5 is formed as a discrete laser dot pattern. Figure 8 In this structure, a portion of the second light-guiding microstructure 5 is formed as discrete laser dots, and another portion is formed as discrete conical dots, with the laser dots and conical dots arranged in a mixed configuration. Figure 9 In this process, each of the second light-guiding microstructures 5 is formed as a discrete conical dot network. Figure 10 In this process, each of the second light-guiding microstructures 5 is formed as a discrete network of short strips. Furthermore... Figures 7 to 10 In this configuration, discrete second light-guiding microstructures 5 are arranged non-periodically (e.g., randomly in position) on the second main surface 2. Figure 11 In this process, each of the second light-guiding microstructures 5 is also formed as discrete laser dots, but with... Figure 7 The difference is that these discrete laser dots are arranged in a periodic and regular pattern. Clearly, for Figure 8 to 10 The discrete second light-guiding microstructure 8 shown or omitted in the illustration can also be similar. Figure 11 They are arranged in a regular pattern.

[0095] In the foregoing Figures 7 to 11 In the example, the first light-guiding microstructure 4 and the second light-guiding microstructure 5 can be... Figure 12The density relationship (area ratio) of the second light guide microstructure 5 is arranged to be smaller and smaller in the direction away from the light inlet surface 3, wherein the area ratio refers to the ratio of the projected area of the light guide microstructure on the first or second major surface of the front light guide plate to the area of the first or second major surface of the front light guide plate within a certain area range.

[0096] In Figure 12 , the first light guide microstructure 4 and the second light guide microstructure 5 in the form of laser dots are arranged within the range of 0-7mm from the light inlet surface 3 on the second major surface 2. The area ratio of the second light guide microstructure 5 is between 2% and 5%, and the area ratio gradually decreases (or first increases and then decreases) with the increase of the distance from the light inlet surface 3, and the range is preferably controlled outside the effective area (visible area) of the electronic paper display device to prevent the dots from being visible. The area ratio of the first light guide microstructure 4 is between 1% and 2%, and the value remains basically unchanged. The experimental results of the whole machine after the front light guide plate with the first light guide microstructure 4 and the second light guide microstructure 5 arranged in the manner shown in Figure 17 are shown. As a comparison, Figure 18 , the experimental results of the whole machine after the front light guide plate with only the first light guide microstructure 4 arranged in the manner shown in Figure 12 are shown. In Figure 17 and Figure 18 , the light inlet surface 3 is located at the lower side, and it can be seen that the through dark band at the light inlet has been alleviated or even completely eliminated by increasing the second light guide microstructure 5.

[0097] In addition, in the example shown in Figures 7 to 11 , the first light guide microstructure 4 and the second light guide microstructure 5 can also be arranged in the density relationship shown in Figure 13 , wherein the area ratio of the first light guide microstructure 4 is fixed at about 1.3%, and the area ratio of the second light guide microstructure 5 first increases and then decreases with the increase of the distance from the light inlet surface 3, and is generally between 0.5% and 8%.

[0098] In a more specific embodiment, the front light guide plate 300 adopts a PC substrate with a thickness of 0.25mm, and the first light guide microstructure 4 in the form of conventional laser dots is arranged on the first major surface 1, and the microstructure density is adjusted so that the light energy distribution emitted from the first major surface 1 is as shown in the "LGP" curve in Figure 14 . Then, the front light guide plate 300 is laminated with OCA glue and a light-transmitting cover plate 400, wherein the thickness of the OCA glue is 0.125mm, and the light-transmitting cover plate 400 is a glass cover plate with a thickness of 0.33mm. At this time, the light energy distribution emitted from the upper surface of the light-transmitting cover plate 400 is as shown in the "LGP+cover" curve in Figure 14The "With Cover" curve and Figure 14 As shown, a noticeable through-blind band phenomenon appears at a distance of 6 mm from the incident light surface 3. Now, second light-guiding microstructures 5 are respectively set in areas at a distance of 8.5 mm and 10 mm from the incident light surface 3 on the second main surface 2 of the front light guide plate 300, and after OCA adhesive and a light-transmitting cover plate 400 are attached, the light intensity distribution emitted from the upper surface of the light-transmitting cover plate 400 is as follows. Figure 14 The curves "Adding dots D = 8.5mm" and "Adding dots D = 10" are shown in the figure. More specifically, for the case corresponding to the "Adding dots D = 8.5mm" curve, the second light-guiding microstructure 5 is not set in the area of ​​0-3.5mm from the light-incident surface 3 (left blank), and only in the range of 3.5-8.5mm from the light-incident surface 3 is a similar Figure 13 Multiple second light-guiding microstructures 5 are set up in this way; the difference is that, for the case corresponding to the curve "Adding dots D=10mm", similar to the method, the light guide microstructures are set up in the full range of 0-10mm from the incident light surface 3. Figure 12 The second light-guiding microstructure 5 was set up in this manner.

[0099] in addition, Figure 16 for Figure 14 The simulated light intensity distribution diagram corresponding to the curve "Adding dots D=8.5mm" is shown below. Figure 14 and Figure 16 It can be seen that by arranging a second light-guiding microstructure 5 with the aforementioned characteristics on the second main surface 2 of the front light guide plate 300, the problem of the through dark band at the light inlet of the electronic paper display device 1000 can be improved or even eliminated.

Claims

1. A front light guide plate applied to an electronic paper display device including an electronic paper display panel, characterized by, The front light guide plate includes: a light incident surface located at a side of the front light guide plate in an extension direction of the front light guide plate; a second major surface located at one side of the front light guide plate in a thickness direction of the front light guide plate, and having an abutment region abutting the light incident surface, the second major surface facing the electronic paper display panel; a plurality of second light guide microstructures provided in the abutment region of the second major surface, and the plurality of second light guide microstructures being discrete microstructures spaced apart from each other.

2. The front light guide plate according to claim 1, wherein The second light guide microstructures are configured to guide second light rays directed toward the second light guide microstructures to exit from a second region of the second major surface, the second region being a region abutting the light incident surface.

3. The front light guide plate according to claim 2, wherein The second light rays are light rays directly from the light incident surface.

4. The front light guide plate according to claim 3, wherein In all light rays directly from the light incident surface and directed toward the second light guide microstructures, the intensity proportion of the second light rays is not less than 10%.

5. The front light guide plate according to claim 2, wherein, In a case where the abutment region is assumed to be a flat surface without the second light guide microstructures provided therein, the second light rays would be totally reflected in the abutment region to be directed toward the first major surface, and eventually exit from a third region of the first major surface or from a fourth region of the second major surface, wherein the third region is a region spaced apart from the light incident surface by at least 6 mm, and the fourth region is a region further away from the light incident surface than the second region.

6. The front light guide plate according to claim 2, wherein The first major surface is further included at the other side of the front light guide plate in the thickness direction of the front light guide plate; The second light rays exiting from the second region return to the front light guide plate via reflection of the electronic paper display panel, and exit from a first region of the first major surface, the first region being a region abutting the light incident surface.

7. The front light guide plate according to claim 6, wherein The second light rays exiting from the second region of the second major surface return to the front light guide plate via reflection of the electronic paper display panel, and exit from the first region of the first major surface in the front light guide plate in a manner that does not cause total reflection, the first region being a region abutting the light incident surface.

8. The front light guide plate according to claim 7, wherein The second light rays exiting from the second region of the second major surface return to the front light guide plate via reflection of the electronic paper display panel, and exit from the first region of the first major surface based on guidance of the corresponding second light guide microstructure.

9. The front light guide plate according to claim 6, wherein, A width of each of the abutment region, the first region, and the second region in a first direction is not more than 15 mm, wherein the first direction is a direction perpendicular to a second direction and the thickness direction, and the second direction is a direction parallel to the light incident surface and perpendicular to the thickness direction.

10. The front light guide plate according to claim 2, wherein, A width of each of the abutment region and the second region in a first direction is not more than 15 mm, wherein the first direction is a direction perpendicular to a second direction and the thickness direction, and the second direction is a direction parallel to the light incident surface and perpendicular to the thickness direction.

11. The front light guide plate according to claim 2, wherein A width of each of the abutment region and the second region in a first direction is not more than 1 / 10 of a size of the front light guide plate in the first direction, wherein the first direction is a direction perpendicular to a second direction and the thickness direction, and the second direction is a direction parallel to the light incident surface and perpendicular to the thickness direction.

12. The front light guide plate according to claim 1, wherein, An area duty cycle of the second light guide microstructure in the abutment region is 0.5% to 8%.

13. The front light guide plate according to claim 12, wherein, The area duty cycle of the second light guide microstructure in the abutment region varies according to a distance to the light incident surface.

14. The front light guide plate according to any one of claims 1 to 13, wherein, Further comprising a first main surface on the other side of the front light guide plate in the thickness direction; The second light guide microstructure is configured to guide a first light ray, which is directed to the second light guide microstructure, to a first region of the first main surface and emit from the first region, the first region being a region adjacent to the light incident surface.

15. The front light guide plate according to claim 14, wherein, In a case where the abutment region is assumed to be a flat surface without the second light guide microstructure, the first light ray would be totally reflected in the abutment region to be directed to the first main surface, and eventually emitted from a third region of the first main surface or from a fourth region of the second main surface, wherein the third region is a region farther from the light incident surface than the first region, and the fourth region is a region farther from the light incident surface than the second region.

16. The front light guide plate according to claim 15, wherein, The second light ray is a light ray directly from the light incident surface.

17. The front light guide plate according to claim 16, wherein, An intensity proportion of the second light ray is not less than 10% among all light rays directly from the light incident surface and directed to the second light guide microstructure.

18. The front light guide plate according to claim 17, wherein, A width of each of the abutment region and the first region in a first direction is not more than 15 mm, wherein the first direction is a direction perpendicular to a second direction and the thickness direction, and the second direction is a direction parallel to the light incident surface and perpendicular to the thickness direction.

19. An electronic paper display device, characterized by comprising: Comprise: The front light guide plate according to any one of claims 1 to 18; The electronic paper display panel; A light source configured on the light incident surface side.

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