Front-lit module having light guide strip, and electronic reader

Abstract

A front-lit module having a light guide strip, the front-lit module including a point light source, a light guide strip and a front-lit panel. The light guide strip comprises a light-incident surface, a reflecting surface connected to the light-incident surface, a light-emergent surface connected to the light-incident surface and located opposite the reflecting surface, and a plurality of first microstructures arranged on the reflecting surface, wherein each first microstructure is an asymmetric microstructure. The front-lit panel has a reference surface facing the light-emergent surface of the light guide strip, and a plurality of second microstructures arranged on the reference surface. Light from the point light source passes through the light guide strip to form a line light source, and then passes through the front-lit panel to form a surface light source; moreover, by means of the cooperation between the first microstructures of the light guide strip and the second microstructures of the front-lit panel, a light-mixing distance can be reduced, and a display range is expanded, and thus the requirements of a narrow frame are met. Further provided in the present invention is an electronic reader including the front-lit module.

Description

Front light module with light guide strip and electronic reader Technical Field

[0001] The present invention relates to an optical component, in particular to a front light module and an electronic reader. Background Art

[0002] Nowadays, in order to allow users to clearly see the content displayed by the e-reader in a dark or bright environment, a front-lit display is used in the e-reader. The front-lit display includes a front-light module and a display panel. The front-light module includes a front-light plate and a light-emitting unit arranged adjacent to each other. The front-light plate has a light-emitting surface. The light emitted by the light-emitting unit is incident on one end of the front-light plate and is refracted by the front-light plate and emitted to the display panel. The display panel then emits the light from the light-emitting surface into the user's eyes. The front-lit display forms an image by reflecting light, thereby avoiding the interference of light in a bright light environment on the display image.

[0003] With technological advancements, portable electronic products are increasingly demanding narrow bezel designs to increase display area. Furthermore, achieving this narrow bezel requires ensuring uniformity across the light-emitting surface to avoid hotspots along the edges. Therefore, improving the internal structure of existing products to increase the display area and provide better light uniformity has become a key R&D goal for manufacturers.

[0004] Summary of the Invention

[0005] Therefore, an object of the present invention is to provide a front light module that can reduce the light mixing distance to increase the display range and improve the light uniformity at the edge.

[0006] A frontlight module with a light guide strip comprises a point light source, a light guide strip for receiving light from the point light source, and a frontlight plate for receiving light emitted by the light guide strip. The light guide strip includes a light incident surface, a reflective surface connected to the light incident surface, a light emitting surface connected to the light incident surface and opposite the reflective surface, and a plurality of first microstructures disposed on the reflective surface, each of the first microstructures being an asymmetric microstructure. The frontlight plate has a reference surface facing the light emitting surface of the light guide strip, and a plurality of second microstructures disposed on the reference surface.

[0007] Another technical means of the present invention is that each of the first microstructures of the light guide strip has a light-facing surface for reflecting light, and an angle θ between the light-facing surface and the reflecting surface is 3 to 25 degrees, inclusive.

[0008] Another technical means of the present invention is that the first microstructures of the light guide strip are asymmetric protrusions, and the distribution density of the first microstructures is denser in a direction away from the point light source.

[0009] Another technical means of the present invention is that the cross-sectional shape of each of the second microstructures of the front light plate is an isosceles triangle.

[0010] Another technical means of the present invention is that the cross-sectional shape of each of the second microstructures of the front light plate is a non-isosceles triangle, and has a first active surface and a second active surface connected to each other, the first active surface is farther away from the point light source than the second active surface, and there is a first angle θ1 between the first active surface and the reference plane, and there is a second angle θ2 between the second active surface and the reference plane, and the first angle θ1 is smaller than the second angle θ2.

[0011] Another technical means of the present invention is that the first angle θ1 is between 50 and 70 degrees, and the second angle θ2 is between 70 and 90 degrees, both inclusive.

[0012] Another technical means of the present invention is that the light guide bar further includes a plurality of strip-shaped microstructures disposed on the light-emitting surface, and the strip-shaped microstructures extend along a first direction.

[0013] Another technical solution of the present invention is that the second microstructure extends along a second direction, and the first direction is perpendicular to the second direction.

[0014] Another technical means of the present invention is that each of the strip-shaped microstructures is an arc-shaped surface with a central angle of 70 to 100 degrees, including endpoint values.

[0015] Another technical solution of the present invention is that the thickness of the light guide strip gradually decreases in a direction away from the point light source.

[0016] Another technical means of the present invention is that the front light module further includes at least one reflective member covering the light guide bar, and the reflective member covers the area of ​​the light guide bar other than the light emitting surface.

[0017] Another technical means of the present invention is that the front light module further includes at least one light shielding member covering the light guide bar, and the light shielding member covers one end of the light guide bar adjacent to the point light source but does not shield the light incident surface of the light guide bar.

[0018] Another technical means of the present invention is that the shading element and the reflecting element do not overlap.

[0019] Another object of the present invention is to provide an electronic reader comprising a front light module as described above, and a display panel disposed on the front light module.

[0020] The effectiveness of the present invention lies in that the light from the point light source forms a line light source after passing through the light guide strip, and then forms a surface light source after passing through the front light plate. In addition, by means of the first microstructure on the reflective surface of the light guide strip and the second microstructure of the front light plate, the light mixing distance at the light incident edge of the front light plate can be shortened, thereby increasing the display range and meeting the requirements of narrow-framed e-readers. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a schematic diagram of a preferred embodiment of a front light module of the present invention;

[0022] FIG2 is a schematic diagram showing a partial removal of a light shielding member and a reflective member that shield a light guide strip in FIG1 ;

[0023] FIG3 is a side sectional view taken along the section line III-III in FIG2 , illustrating the relative positional relationship between the reflector and the light guide strip;

[0024] FIG4 is a side view schematically illustrating the relative positional relationship between the light shielding member and the light guide strip;

[0025] FIG5 is a schematic top view illustrating the morphology of a plurality of first microstructures of the light guide strip;

[0026] FIG6 is a bottom view schematically illustrating the morphology of multiple strip-shaped microstructures of the light guide strip;

[0027] FIG7 is a schematic diagram illustrating a partial enlargement of the area indicated by the frame in FIG2; and

[0028] FIG8 is a side view schematically showing a preferred embodiment of the electronic reader of the present invention. DETAILED DESCRIPTION

[0029] The features and technical content of the related patent applications of this invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the accompanying drawings. Before proceeding with the detailed description, it should be noted that similar components are represented by the same reference numerals. Directional terms mentioned in the following embodiments, such as "up," "down," "left," "right," "front," "back," "bottom," and "top," are merely references to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes only and are not intended to limit the present invention.

[0030] Referring to Figures 1 and 2, a first preferred embodiment of the front light module of the present invention is shown, which includes a point light source 2, a light guide bar 3 for receiving light from the point light source 2, and a front light plate 4 for receiving light emitted by the light guide bar 3. As shown in Figure 2, the light guide bar 3 includes a light incident surface 31, a reflective surface 32 connected to the light incident surface 31, a light emitting surface 33 connected to the light incident surface 31 and opposite to the reflective surface 32, and a plurality of first microstructures 34 arranged on the reflective surface 32. Each of the first microstructures 34 is an asymmetric microstructure. The front light plate 4 has a reference surface 41 facing the light emitting surface 33 of the light guide bar 3, and a plurality of second microstructures 42 arranged on the reference surface 41. For example, the point light source 2 can be a collection of multiple LEDs, and is correspondingly arranged on the light incident surface of the light guide bar 3. If high brightness is not required, the point light source 2 can also be a single LED. Preferably, the light-emitting surface of the single LED can correspond to the light-entering surface 31 of the light guide bar 3. Through this design, light from the point light source 2 forms a linear light source after passing through the light guide bar 3, and then forms a surface light source after passing through the front light plate 4. The first microstructure 34 on the reflective surface 32 of the light guide bar 3, combined with the second microstructure 42 of the front light plate 4, can reduce the light mixing distance at the light-entering edge of the front light plate 4, thereby increasing the display range and meeting the requirements of narrow-frame e-readers.

[0031] For example, in this embodiment, a single LED 4 is used as the light source of the frontlight module, and its edges do not produce a bright spot distribution similar to that of conventional e-readers. In particular, the second microstructure 42 can further evenly disperse the light within the frontlight plate 4. It should be noted that the frontlight plate 4 includes a light-emitting surface 43 connected to the reference surface 41. The light-emitting surface 43 has a plurality of reflective microstructures 44, which are similar to the first microstructures 34 of the light guide bar 3. The reflective microstructures 44 (shown in FIG8 ) are arranged in a sparse to dense manner along the light propagation direction (third direction D3) on the light-emitting surface 43. More specifically, after the frontlight plate 4 receives light from the light guide bar 3, the light traveling along the Y direction (such as the third direction D3) within the frontlight plate 4 can be reflected by the reflective microstructures 44 on the light-emitting surface 43 and turned to the Z direction (second direction D2). As shown in FIG8 , the light hits the display panel 5 located on the bottom surface, is reflected, and then emitted from the light-emitting surface 43 of the frontlight plate 4. For example, the reflective microstructure 44 is a microstructure recessed in the light emitting surface 43 , and its shape can be symmetrical or asymmetrical.

[0032] The front light module also includes at least one reflective component 35 covering the light guide bar 3, and at least one light shielding component 36 covering the light guide bar 3. In order to facilitate the explanation of the detailed structure and the direction of travel of the light, a portion of the reflective component 35 and the light shielding component 36 are removed in Figure 2. Figure 3 is a cross-sectional view of the position of the cutting line III-III in Figure 2. As shown in Figure 3, the reflective component 35 covers the area outside the light-emitting surface 33 of the light guide bar 3. Referring to Figures 2 and 4, the light shielding component 36 covers one end of the light guide bar 3 adjacent to the point light source 2 but does not block the light incident surface 31 of the light guide bar 3. As shown in Figure 2, in this embodiment, the covering positions of the reflective component 35 and the light shielding component 36 do not overlap with each other. It should be noted that the shading member 36 is used to prevent the light from the point light source 2 from directly emitting light after entering the light guide bar 3, thereby preventing light leakage. Therefore, it covers the end of the light guide bar 3 adjacent to the point light source 2 but does not block the light incident surface 31, ensuring that the light from the point light source 2 can enter through the light incident surface 31 and continue to travel within the light guide bar 3, while also providing a sufficient light mixing distance. Since most of the light within the light guide bar 3 is reflected by the first microstructure 34 and then turns to emit light from the light emitting surface 33, while a small portion of the light will be emitted from the reflective surface 32 of the light guide bar 3, the reflective member 35 is used to allow the light within the light guide bar 3 that is not reflected by the first microstructure 34 to be reflected by the reflective member 35 and then return to the light guide bar 3, and then emit light from the light emitting surface 33, thereby improving the light utilization rate. Therefore, except for the light emitting surface 33 and the area covered by the light shielding element 36 , the entire light guide bar 3 is almost shielded by the reflective element 35 .

[0033] Referring to Figure 5, which shows a top view of the light guide strip 3 after the reflector 35 is removed, the first microstructures 34 of the light guide strip 3 are asymmetrical protrusions, and the distribution density of the first microstructures 34 increases as the distance from the point light source 2 increases. In other words, the arrangement density of the first microstructures 34 increases with increasing distance from the point light source 2. By arranging the first microstructures 34 at different densities, light output can be made more uniform. It should be noted that the first microstructures 34 are an integral structure of the light guide strip 3, so there is no physical boundary between the first microstructures 34 and the reflective surface 32 on the light guide strip 3.

[0034] Referring to Figures 6 and 7 , the light guide bar 3 further includes a plurality of strip-shaped microstructures 37 disposed on the light exit surface 33. The strip-shaped microstructures 37 extend along a first direction D1. This first direction D1 is parallel to the optical axis of the point light source 2. As shown in Figure 3 , each strip-shaped microstructure 37 is an arc-shaped surface with a central angle of 70 to 100 degrees, inclusive. In this embodiment, light traveling along the X direction within the light guide bar 3 is reflected by the first microstructures 34 on the reflective surface 32 to form directional light. The strip-shaped microstructures 37 on the light exit surface 33 then redirect the light in the Y direction and spread it along the YZ plane formed by the Y and Z directions, facilitating light reception by the second microstructures 42 of the front light panel 4 below. Furthermore, the intersecting extension directions of the strip-shaped microstructures 37 and the second microstructures 42 facilitate spreading the directional light along different planes, such as the YZ plane and the XY plane, thereby increasing the breadth of the light path. In more detail, each of the strip microstructures 37 has an arc-shaped periphery in a cross section along a second direction D2. The shape and length of the arc-shaped periphery correspond to the shape and length of an arc with a central angle of 70 to 100 degrees. The first direction D1 is perpendicular to the second direction D2.

[0035] Referring to FIG. 7 , which is an enlarged view of the area indicated by the frame A in FIG. 2 , each of the first microstructures 34 of the light guide strip 3 is an asymmetric microstructure and has a light-facing surface 341 for reflecting light. The angle θ between the light-facing surface 341 and the reflective surface 32 is between 3 and 25 degrees, inclusive.

[0036] The second microstructures 42 of the front light plate 4 extend along the second direction D2. Each of the second microstructures 42 of the front light plate 4 has a non-isosceles triangle cross-sectional shape along the first direction D1 and has a first active surface 421 and a second active surface 422 connected to each other. The first active surface 421 is farther away from the point light source 2 than the second active surface 422. The first active surface 421 and the second active surface 422 of each second microstructure 42 extend along the second direction D2. A first angle θ1 is formed between the first active surface 421 and the reference plane 41, and a second angle θ2 is formed between the second active surface 422 and the reference plane 41. The first angle θ1 is smaller than the second angle θ2. The first angle θ1 is between 50 and 70 degrees, and the second angle θ2 is between 70 and 90 degrees, inclusive. In this way, the asymmetric second microstructures 42 arranged along the X direction are used to receive light from the light guide bar 3, especially these light rays have an angle of about 60 to 75 degrees with the Y direction. Therefore, each first angle θ1 of a smaller angle can efficiently receive the aforementioned oblique light from the light guide bar 2 and can efficiently reflect the aforementioned light toward the Y direction. In some embodiments, the cross-sectional shape of each of the second microstructures 42 can also be an isosceles triangle, which has the advantage of being easy to manufacture and form. It should be noted that the second microstructure 42 is a microstructure of the reference plane 41 of the front light panel 4 for refracting and reflecting light, and the second microstructure 42 is a structure integrally formed on the front light panel 4. There is no physical boundary between the second microstructure 42 and the reference plane 41 on the front light panel 4.

[0037] Referring to Figures 2 and 7, since the light guide bar 3 is covered by the light shielding member 36 and the reflective member 35, when the light from the point light source 2 enters the light guide bar 3 from the light incident surface 31, it will be reflected within the light guide bar 3 and will be emitted from the area of ​​the light emitting surface 33 that is not covered by the light shielding member 36 and the reflective member 35. Asymmetric first microstructures 34 are formed on the reflective surface 32 of the light guide bar 3. Light will be reflected by the reflective surface 32 and the light-facing surface 341 of each of the first microstructures 34 and will be emitted from the light emitting surface 33. By designing the angle θ between the light-facing surface 341 and the reflective surface 32, light can be reflected toward the light emitting surface 33. It should be noted that the reflective member 35 has the characteristics of mirror reflection, which can ensure that no light is leaked and improve the light reuse rate. In addition, since the mirror reflection of the reflector 35 is parallel reflection and the first microstructure 34 on the light guide bar 3 has high light directivity, it is beneficial for the front light plate 4 to receive light at a correct angle.

[0038] Next, the strip-shaped microstructure 37 on the light-emitting surface 33 is an arc-shaped surface with a central angle of 70 to 100 degrees, further concentrating the light emission angle so that the light has a light emission angle of 60 to 75 degrees when passing through the light-emitting surface 33 of the light-guiding strip 3. Utilizing the aforementioned structural design of the light-guiding strip 3, the light from the point light source 2 can be transformed into a uniform line light source, and the design of the first microstructure 34 can ensure that the luminous intensity at each position in the line light source is equal. In addition, in this embodiment, the thickness of the light-guiding strip 3 gradually decreases in the direction away from the point light source 2, and the area of ​​the anti-light-entering surface is smaller than the area of ​​the light-entering surface, forming the light-guiding strip 3 into a wedge shape. The shape is designed to improve light utilization. For example, the light emitted by an LED has a specific angular range. For easier understanding, only light rays L1, L2, and L3 are illustrated in Figure 2. Light ray L1, which first encounters the first microstructure 34, is reflected and redirected earlier than light ray L2, and light ray L2 is reflected and redirected earlier than light ray L3. In this way, light rays of different angles are dispersed and reflected along the first direction D1, thereby achieving the effect of improving light utilization efficiency. However, if the size of the point light source 2 is small, the light guide strip 3 can also be a long strip with uniform thickness, and is not limited to the embodiment disclosed.

[0039] Light from the point light source 2 is converted into a linear light source by the light guide strip 3 before entering the front light panel 4. At this point, the light is refracted by the second active surface 422 of each of the second microstructures 42 and then reflected by the first active surface 421, redirecting the light perpendicularly and away from the reference plane 41, transforming the front light panel 4 into a surface light source. Referring to Figure 8 , a display panel 5 is disposed on the bottom surface of the front light panel 4, spaced apart from the light-emitting surface 43, forming a preferred embodiment of the electronic reader of the present invention.

[0040] In summary, the front light module of the present invention utilizes the structural design of the light guide bar 3 to allow the light from the point light source 2 to form a line light source after passing through the light guide bar 3, and then form a surface light source after passing through the front light plate 4. In addition, by means of the first microstructure 34 on the reflective surface 32 of the light guide bar 3, in combination with the second microstructure 42 of the front light plate 4, the light mixing distance at the light incident edge of the front light plate 4 can be shortened, thereby increasing the display range, meeting the requirements of narrow-frame electronic readers, and indeed achieving the purpose of the present invention.

[0041] However, the above is only a preferred embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. In other words, simple equivalent changes and modifications made according to the description and content of the present invention are still within the scope of the patent of the present invention.

[0042] [Explanation of Symbols] 2 Point light source 3 Light guide strip 31 Light incident surface 32 Reflection surface 33 Light exit surface 34 First microstructure 341 Light-facing surface 35 Reflection element 36 Light shielding element 37 Strip microstructure 4 Front light plate 41 Reference surface 42 Second microstructure 421 First active surface 422 Second active surface 43 Light exit surface 44 Reflection microstructure 5 Display panel A Frame position D1 First direction D2 Second direction θ Angle θ1 First angle θ2 Second angle

Claims

1. A front light module with a light guide strip, comprising: Point light source; a light guide bar for receiving light from the point light source, the light guide bar comprising a light incident surface, a reflective surface connected to the light incident surface, a light emitting surface connected to the light incident surface and opposite to the reflective surface, and a plurality of first microstructures disposed on the reflective surface, each of the first microstructures being an asymmetric microstructure; and The front light plate is used for receiving the light emitted by the light guide bar. The front light plate has a reference surface facing the light emitting surface of the light guide bar and a plurality of second microstructures arranged on the reference surface.

2. The front light module with light guide strips according to claim 1, wherein: Each of the first microstructures of the light guide strip has a light-facing surface for reflecting light, and an angle θ between the light-facing surface and the reflecting surface is 3 to 25 degrees, inclusive.

3. The front light module with light guide strips according to claim 1, wherein: The first microstructures of the light guide strip are asymmetric convex points, and the distribution density of the first microstructures becomes denser along the direction away from the point light source.

4. The front light module with light guide strips according to claim 1, wherein: The cross-sectional shape of each of the second microstructures of the front light plate is an isosceles triangle.

5. The front light module with light guide strips according to claim 1, wherein: The cross-sectional shape of each of the second microstructures of the front light plate is a non-isosceles triangle, and has a first active surface and a second active surface connected, the first active surface is farther away from the point light source than the second active surface, a first angle θ1 is formed between the first active surface and the reference plane, and a second angle θ2 is formed between the second active surface and the reference plane, and the first angle θ1 is smaller than the second angle θ2.

6. The front light module with light guide strips according to claim 5, wherein: The first angle θ1 is in a range of 50 to 70 degrees, and the second angle θ2 is in a range of 70 to 90 degrees, both inclusive.

7. The front light module with light guide strips according to claim 1, wherein: The light guide bar further includes a plurality of strip-shaped microstructures arranged on the light-emitting surface, and the strip-shaped microstructures extend along a first direction.

8. The front light module with light guide strips according to claim 7, wherein: The second microstructure extends along a second direction, and the first direction is perpendicular to the second direction.

9. The front light module with light guide strips according to claim 7, wherein: Each of the strip-shaped microstructures is an arc-shaped surface with a central angle of 70 to 100 degrees, inclusive.

10. The front light module with light guide strips according to claim 1, wherein: The thickness of the light guide strip gradually decreases along a direction away from the point light source. 11 . The front light module with a light guide bar as claimed in claim 1 , further comprising at least one reflective element covering the light guide bar, wherein the reflective element covers an area of ​​the light guide bar other than the light emitting surface. 12 . The front light module with a light guide bar as claimed in claim 11 , further comprising at least one light shielding member covering the light guide bar, wherein the light shielding member covers an end of the light guide bar adjacent to the point light source but does not shield the light incident surface of the light guide bar.

13. The front light module with light guide strips according to claim 12, wherein: The light shielding element does not overlap with the reflecting element.

14. An electronic reader comprising the front light module having the light guide strip according to any one of claims 1 to 13, and a display panel spaced apart from the front light module.

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