Front light module and display device using same
By employing a folded light guide plate with a parabolic reflection design in a reflective display device, light is evenly distributed using a single point light source, solving the high power consumption problem caused by long strip light bars and achieving a low power consumption light distribution effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2026-03-24
AI Technical Summary
In existing reflective display devices, the design of long, side-lit LED strips results in excessive energy consumption and serious power consumption problems.
It adopts a folded light guide plate with parabolic reflection design, which uses a single point light source to evenly distribute light to the long cross section through the parabolic reflection layer, replacing the long strip light bar.
It achieves uniform light distribution with low power consumption, reducing the energy consumption of the display device.
Smart Images
Figure CN121721769A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a front light module and a display device using the same. BACKGROUND
[0002] A reflective display device can use a front light module to provide light for a reflective display panel. Specifically, the front light module can be disposed on a display surface of a display panel, such as a reflective display panel or a transflective display panel, where light can be incident on the display panel and reflected by the display panel to display an image. The front light module can include a light emitting element and a light guide assembly, where the light guide assembly can homogenize light emitted by the light emitting element and direct the light into the display panel. However, the light emitting element carried by the conventional light guide assembly is generally a long strip-shaped side-in light bar. When the side length of the light guide plate is long, multiple groups of light emitting units need to be disposed on the light bar to meet the uniform illumination requirement for a large area. However, the display device with this design consumes a large amount of energy and has a high power consumption problem. SUMMARY
[0003] In some embodiments of the present application, a front light module with extremely low power consumption for a reflective display device is provided. A folded light guide plate with a parabolic reflection design is used to uniformly distribute a single point light source into a long cross section, thereby replacing the long strip-shaped light bar to achieve low power consumption.
[0004] According to some embodiments of the present application, a front light module includes a light guide plate element and a light source. The light guide plate element includes a first portion, a second portion, and a curved portion. The second portion has an out-coupling surface, and the second portion is separated from the first portion along a normal direction of the out-coupling surface. The curved portion is connected between the first portion and the second portion. The light source is adjacent to an in-coupling surface of the first portion of the light guide plate element.
[0005] In some embodiments, the first portion of the light guide plate element has a curved surface opposite the curved portion.
[0006] In some embodiments, the front light module further includes a reflective layer on the curved surface of the first portion of the light guide plate element.
[0007] In some embodiments, as viewed from an upper view, in a first direction, the curved surface has a first distance from a first end of the in-coupling surface to the curved portion, and a second distance from a second end of the in-coupling surface to the curved portion, the first distance being greater than the second distance.
[0008] In some embodiments, the curved surface of the first portion of the light guide plate element is a parabolic surface, and the light source is located at a focal point of the parabolic surface.
[0009] In some embodiments, in a cross-sectional view, the first part of the light guide plate element has a thickness along the normal direction, the light source is a square light source, and the side length of the square is 0.95 to 1.05 times the thickness.
[0010] In some embodiments, the second part of the light guide plate element includes multiple microstructures.
[0011] In some embodiments, the microstructure is located on the surface of the second portion opposite the light-emitting surface.
[0012] In some embodiments, the length of the first portion of the light guide plate element along the first direction is less than the length of the second portion of the light guide plate element along the first direction, and the curved portion of the light guide plate element extends along the second direction, wherein the first direction, the second direction, and the normal direction are perpendicular to each other.
[0013] In some embodiments, the light-incident surface of the first portion of the light guide plate element has rounded corners and is adjacent to the light source.
[0014] According to some embodiments of the present invention, the display device includes a front light module and a reflective display panel. The reflective display panel is located between the light-emitting surface of the second portion of the light guide plate element and the first portion. Attached Figure Description
[0015] To gain a more complete understanding of the embodiments and their advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein:
[0016] Figure 1A This is a cross-sectional schematic diagram of a display device according to some embodiments of the present disclosure;
[0017] Figure 1B This is an exploded view of a display device according to a partial embodiment of the present disclosure;
[0018] Figure 2A This is a top view schematic diagram of the first part of the light guide plate element and the reflective layer according to a partial embodiment of the present disclosure;
[0019] Figure 2B for Figure 2A A cross-sectional view of line BB;
[0020] Figure 3 This is a cross-sectional schematic diagram of the bent portion of a light guide plate element according to a partial embodiment of the present disclosure.
[0021] Figure 4A This is a top view schematic diagram of the second part of a light guide plate element according to a partial embodiment of the present disclosure;
[0022] Figure 4B for Figure 4A A cross-sectional view of line BB;
[0023] Figure 5A for Figure 2B A simulated optical path diagram of the first part of the light guide plate element;
[0024] Figure 5B for Figure 1A The simulated optical path diagram of the display device. Detailed Implementation
[0025] The embodiments of this disclosure are discussed in detail below. However, it will be understood that the embodiments provide many applicable concepts that can be implemented in a wide variety of specific contexts. The specific embodiments discussed are for illustrative purposes only and are not intended to limit the scope of this disclosure.
[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the claims. Unless otherwise limited, the singular forms of “a” or “described” may also be used to denote the plural forms.
[0027] It is understood that although the terms “first,” “second,” “third,” etc., as used herein may be used to describe different signals and / or entities, these signals and / or entities should not be limited by these terms. These terms are used only to distinguish one signal and / or entity from other signals and / or entities.
[0028] For the sake of simplicity and clarity, element symbols and / or letters may be repeated in various embodiments herein, but this does not imply a causal relationship between the various embodiments and / or configurations discussed.
[0029] Figure 1A This is a cross-sectional schematic diagram of a display device DE according to a partial embodiment of the present disclosure. The display device DE includes a light guide plate element 100, a light source 200, and a reflective display panel 300. The light guide plate element 100 and the light source 200 constitute a front light module FL, which provides light to the display surface 300D of the reflective display panel 300, and the reflective display panel 300 reflects the light to display an image on the display surface 300D.
[0030] In this disclosed embodiment, the light guide plate element 100 includes a first portion 110, a second portion 120, and a curved portion 130. The first portion 110 and the second portion 120 of the light guide plate element 100 may be light guide plates arranged substantially parallel to each other. For example, the light guide plate arrangement of the first portion 110 and the second portion 120 causes total internal reflection of light in direction Z, allowing light to propagate along directions X and Y. In some embodiments, directions X, Y, and Z are substantially perpendicular to each other. The second portion 120 of the light guide plate element 100 has a light-emitting surface 122, the normal direction 122N of which is substantially parallel to direction Z. The second portion 120 of the light guide plate element 100 is separated from the first portion 110 along the normal direction 122N of the light-emitting surface 122. The curved portion 130 of the light guide plate element 100 extends along direction Y. The curved portion 130 of the light guide plate element 100 connects the first portion 110 and the second portion 120.
[0031] A reflective display panel 300 is located between the light-emitting surface 122 of the second portion 120 of the light guide plate element 100 and the first portion 110. The reflective display panel 300 may include two substrates and a pixel circuit layer, a display medium layer, and / or other components or film layers disposed between the two substrates. The display surface 300D of the reflective display panel 300 is disposed opposite to the light-emitting surface 122. In some embodiments, the pixel circuit layer may include a suitable reflective layer or reflective electrode to reflect light. In some embodiments, the display medium layer may contain a suitable material to reflect light.
[0032] Figure 1B This is an exploded view of a display device DE according to a partial embodiment of the present disclosure. See also... Figure 1A as well as Figure 1B The first portion 110 of the light guide plate element 100 has a light incident surface 111 facing a direction opposite to the Y direction. The light source 200 is adjacent to the light incident surface 111 of the first portion 110 of the light guide plate element 100 to provide light in the Y direction. In some embodiments, the first portion 100 of the light guide plate element has a curved surface 115 disposed opposite the curved portion 130. In some embodiments, the front light module FL further includes a reflective layer 400 located on the curved surface 115 of the first portion 110 of the light guide plate element 100. Thereby, the light provided by the light source 200 is reflected by the reflective layer 400 and transmitted into the curved portion 130.
[0033] Figure 2A This is a top view schematic diagram of the first portion 110 of the light guide plate element 100 and the reflective layer 400 according to a partial embodiment of the present disclosure. Figure 2B for Figure 2AA cross-sectional view along line BB. The upper surface 112 and lower surface 114 of the first portion 110 of the light guide plate element 100 are used to generate total internal reflection. The light incident surface 111 is connected between the upper surface 112 and the lower surface 114. The light incident surface 111 may have a portion 111A, a portion 111B, and a chamfered portion 111C. The portions 111A and 111B are parallel to each other, the portion 111B is offset outward relative to the portion 111A, and the chamfered portion 111C is connected between the portions 111A and 111B. The offset distance between the portions 111A and 111B of the light incident surface 111 can be designed to be greater than half the side length of the light source 200, so as to facilitate the proximity of the light source 200 to the chamfered portion 111C of the light incident surface 111, so that the first portion 110 of the light guide plate element 100 can receive light. From the top view, the chamfered portion 111C may be a rounded corner. For example, the light source 200 may be located at the center of the rounded corner of the chamfered portion 111C.
[0034] In this embodiment, portion 111A of the light-incident surface 111 may be aligned with one end 130E of the curved portion 130 and / or one side 121 of the second portion 120 (see reference). Figure 1B In other words, the first portion 110 has a portion 110P extending beyond one end 130E of the curved portion 130 in the opposite direction Y and / or one side 121 of the second portion 120 (see reference). Figure 1B ).
[0035] The curved surface 115 of the first part 110 connects the upper surface 112 and the lower surface 114. (From a top view, e.g.) Figure 2A From the perspective of direction X, the first end E1 of the curved surface 115 adjacent to the light-incident surface 111 to the curved portion 130 has a distance D1, and the second end E2 of the curved surface 115 away from the light-incident surface 111 to the curved portion 130 has a distance D2, and the distance D1 is greater than the distance D2.
[0036] In some embodiments, surface 115 is a parabolic surface, such as an off-axis parabolic (OAP) surface. When surface 115 is parabolic, light source 200 can be located at the focal point of parabolic surface 115. Thereby, light provided by light source 200 can be reflected by reflective layer 400 located on the parabolic surface, and then uniformly distributed into light guide plate element 100. In some examples, to facilitate light reception and uniform distribution into light guide plate element 100, the focal point of surface 115, the center of the rounded corner of light incident surface 111, and light source 200 can overlap and be located in the same position. Due to manufacturing tolerances, any two of the focal point of surface 115, the center of the rounded corner, and light source 200 may be offset. In a preferred embodiment, the distance between any two of the focal point of surface 115, the center of the rounded corner, and light source 200 is less than 0.1 mm.
[0037] In some embodiments, the side length of the light source 200 is along the Z direction (or...) of the first portion 110. Figure 1A The thickness T1 of the light source 200 is matched to the thickness of the light source 200 in the normal direction (122N) to maintain better light efficiency. For example, when the light source 200 is a square light source, the side length 200E of the square of the light source 200 is 0.95 to 1.05 times the thickness T1. Alternatively, in some embodiments, the light source 200 may have a very small light-emitting area and can be regarded as a point light source.
[0038] Figure 3 This is a cross-sectional schematic diagram of the bent portion 130 of a light guide plate element 100 according to a partial embodiment of the present disclosure. Surfaces 132 and 134 of the bent portion 130 of the light guide plate element 100 are used to generate total internal reflection. The bent portion 130 has a bending curvature that does not disrupt total internal reflection, for use in connecting the first portion 110 (reference...) Figure 1A The light is transmitted to the second part 120 (reference). Figure 1A ).
[0039] Figure 4A This is a top view schematic diagram of the second portion 120 of a light guide plate element 100 according to a partial embodiment of the present disclosure. Figure 4B for Figure 4A A cross-sectional view along line BB. The second portion 120 of the light guide plate element 100 includes regions R1 and R2, wherein region R1 is adjacent to the curved portion 130, and region R2 is further away from the curved portion 130 than region R1. The light-emitting surface 122 and surface 124 of the second portion 120 of the light guide plate element 100 are adapted to produce total internal reflection in region R1 and to disrupt total internal reflection in region R2. Specifically, the second portion 120 of the light guide plate element 100 may include a plurality of microstructures MS distributed in a dotted pattern in region R2. The microstructures MS can disrupt the light transmitted through total internal reflection in the light guide plate, enabling it to change its path and exit at the light-emitting surface 122. By exiting the light at the light-emitting surface 122, the light can be incident on the reflective display panel 300 (reference). Figure 1A and Figure 1B ).
[0040] In this embodiment, the microstructure MS is located on the surface 124 of the second portion 120 opposite to the light-emitting surface 122, but not on the light-emitting surface 122. In other embodiments, the position of the microstructure MS can be configured differently. For example, the microstructure MS can be located on one or both of the light-emitting surface 122 and the surface 124. In this embodiment, the microstructure MS can be a protruding microstructure. In other embodiments, the shape of the microstructure MS can be a recessed microstructure. The cross-sectional shape of the microstructure MS can be semi-circular, triangular, square, etc.
[0041] To accommodate total internal reflection propagation, the first portion 110, the second portion 120, and the curved portion 130 of the light guide plate element 100 can be made of a suitable optical material with a refractive index of 1.4 to 1.58, such as poly(methylmethacrylate) (PMMA).
[0042] The first portion 110, the second portion 120, and the curved portion 130 of the light guide plate element 100 can be formed by bending an integral optical-grade film material suitable for total internal reflection transmission. For example, the first surface of the optical-grade film material is bent to become the upper surface 112 of the first portion 110, the surface 132 of the curved portion 130, and the light-emitting surface 122 of the second portion 120; and the second surface of the optical-grade film material is bent to become the lower surface 114 of the first portion 110, the surface 134 of the curved portion 130, and the surface 124 of the second portion 120. In this embodiment, the upper surface 112 of the first portion 110, the surface 132 of the curved portion 130, and the light-emitting surface 122 of the second portion 120 are continuously connected to each other; and the lower surface 114 of the first portion 110, the surface 134 of the curved portion 130, and the surface 124 of the second portion 120 are continuously connected to each other.
[0043] See again Figure 1B The first portion 110 of the light guide plate element 100 has lengths 110S and 110L along directions X and Y, respectively. The second portion 120 of the light guide plate element 100 has lengths 120S and 120L along directions X and Y, respectively. The reflective display panel 300 has lengths 300S and 300L along directions X and Y, respectively. In some embodiments, as shown in the figure, the lengths 120S, 300S, and 110S decrease sequentially, while the lengths 110L, 300L, and 120L are substantially equal. In some embodiments, the display device DE has direction X as its short side and direction Y as its long side; therefore, the lengths 110S, 300S, and 120S are smaller than the lengths 110L, 300L, and 120L, respectively. In other embodiments, the display device DE can have direction X as its long side and direction Y as its short side, so the lengths 110S, 300S, and 120S are greater than the lengths 110L, 300L, and 120L, respectively.
[0044] Figure 5A for Figure 2A The simulated optical path diagram of the first part 110 of the light guide plate element 100. The first part 110 of the light guide plate element 100 receives light from the light source 200 placed on the light incident surface 111 and distributes the light source evenly to the long side cross-sectional area of the entire light guide plate element 100 through the parabolic reflection surface 115, and transmits it through total internal reflection in the X direction.
[0045] Then, refer to Figure 5B ,Figure 5B for Figure 1A The simulated optical path diagram of the display device DE. The curved portion 130 of the light guide plate element 100 receives light from the first portion 110 and transmits the light to the second portion 120 by total internal reflection. Then, the second portion 120 receives light from the curved portion 130 and transmits it to the region R2 with the dot matrix microstructure MS by total internal reflection in region R1. In region R2, the total internal reflection of the light is broken by the microstructure MS, and the light is incident on the reflective display panel 300. Figure 5A and Figure 5B The optical path shown is merely an example and should not be construed as limiting the scope of the invention.
[0046] In several embodiments of the present invention, an ultra-low power front light module design suitable for reflective display devices is proposed. By utilizing a folded light guide plate with a parabolic reflective design, a single point light source can be uniformly distributed into an elongated cross-section, thereby replacing a long strip of light and achieving low power consumption.
[0047] The above summarizes the features of several embodiments. Those skilled in the art will understand that this invention can serve as the basis for designing or modifying other processes or structures, and various changes, substitutions, and transformations can be made. The spirit and scope of this invention encompass these changes, substitutions, and transformations. In particular, this invention is also applicable to display devices containing reflective structures, such as transflective or micro-transflective display devices.
Claims
1. A front optical module, characterized in that, Include: A light guide plate element, comprising: Part One; A second portion having a light-emitting surface, wherein the second portion is separated from the first portion along a normal direction of the light-emitting surface; and A curved portion connecting the first portion and the second portion; and a light source adjacent to a light-incident surface of the first portion of the light guide plate element.
2. The front optical module as described in claim 1, characterized in that, The first portion of the light guide plate element has a curved surface disposed relative to the curved portion.
3. The front optical module as described in claim 2, characterized in that, Also includes: A reflective layer is located on the curved surface of the first portion of the light guide plate element.
4. The front optical module as described in claim 2, characterized in that, From a top view, in a first direction, the curved surface has a first distance from a first end adjacent to the light-incident surface to the curved portion, and a second distance from a second end of the curved surface away from the light-incident surface to the curved portion, wherein the first distance is greater than the second distance.
5. The front optical module as described in claim 2, characterized in that, The curved surface of the first portion of the light guide plate element is a parabola, and the light source is located at a focal point of the parabola.
6. The front optical module as described in claim 1, characterized in that, In a cross-sectional view, the light source is a square light source, the first part of the light guide plate element has a thickness along the normal direction, and the side length of the square is 0.95 to 1.05 times the thickness.
7. The front optical module as described in claim 1, characterized in that, The second portion of the light guide plate element comprises a plurality of microstructures.
8. The front optical module as described in claim 7, characterized in that, The plurality of microstructures are located on one surface of the second part opposite to the light-emitting surface.
9. The front optical module as described in claim 1, characterized in that, The first portion of the light guide plate element has a length along a first direction that is less than the length of the second portion of the light guide plate element along the first direction, and the curved portion of the light guide plate element extends along a second direction, wherein the first direction, the second direction, and the normal direction are perpendicular to each other.
10. The front optical module as described in claim 1, characterized in that, The light-incident surface of the first portion of the light guide plate element has a rounded corner adjacent to the light source.
11. A display device, characterized in that, Include: The front optical module as described in claim 1; and A reflective display panel is located between the light-emitting surface of the second portion of the light guide plate element and the first portion.