A reflective multi-deck module with front light and display device

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By setting transition pixels at the edge of the effective display area of the lower LCD panel or moving the light-blocking area outward, the problem of color layering in reflective displays under low light conditions is solved, achieving uniform color mixing across the entire area and improving the picture quality and visual effect of the display module.

CN121995671BActive Publication Date: 2026-07-31ANHUI YUTU TECH CO LTD

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Patent Information

Authority / Receiving Office: CN · China
Patent Type: Patents(China)
Current Assignee / Owner: ANHUI YUTU TECH CO LTD
Filing Date: 2026-04-08
Publication Date: 2026-07-31

AI Technical Summary

Technical Problem

In low-light environments, reflective displays suffer from color layering and incomplete color mixing at the screen edges due to the front light entering the screen at a certain angle, affecting the overall uniformity and image quality of the displayed image.

Method used

Transition pixels or outward-moving light-blocking areas are set at the edge of the effective display area of the lower LCD panel, so that the large-angle incident light from the front light can be fully reflected and mixed with the pixels of each screen layer in the final effective display area. By designing that the transition pixels and the adjacent effective display area pixels are controlled by the same circuit, it is ensured that the light is fully mixed in the display area.

Benefits of technology

It completely eliminates the color layering phenomenon at the screen edge, achieves uniform color mixing across the entire area, and significantly improves the overall display quality and visual effect of the display module.

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Abstract

This invention relates to the field of reflective liquid crystal display technology. The invention discloses a reflective multi-layer screen module and display device with front light. A front light guide plate is located on one side of the display module, and a supplementary light source is located at the end of the front light guide plate near the non-display area. This allows the light emitted from the supplementary light source to be uniformly diffused by the front light guide plate before entering the reflective liquid crystal panel. By setting transition pixels or moving the light-blocking area outward at the edge of the effective display area on the light source side of the lower screen, the large-angle incident light from the front light can be fully reflected and mixed by the corresponding pixels of each screen layer within the final effective display area. This completely eliminates the color layering phenomenon at the screen edge when the front light is on, achieving uniform color mixing across the entire area and significantly improving the overall display quality and visual effect of the display module.

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Description

Technical Field

[0001] This invention relates to the field of reflective liquid crystal display technology, and more particularly to a reflective multi-screen module and display device with front light. Background Technology

[0002] Reflective displays, as a low-power display technology, are widely used in electronic price tags, portable devices, and other fields. Color reflective displays typically employ a multi-layered liquid crystal panel structure, achieving color display by reflecting light of a different color from each liquid crystal panel. Since reflective displays rely on reflecting ambient light, to improve visibility in low-light environments, they usually integrate a light guide plate and a light source on the front side to form a front lighting system. The light source is located at one end of the light guide plate, which distributes the light across the top of the panel.

[0003] The display panel includes a display area with display pixels and a non-display area for circuit connections, etc. The non-display area is shielded by a BM (black matrix) area. The light rays from the light guide plate on the light source side of the non-display area entering the screen are at an angle, and this portion of the light falls precisely at the edge of the BM area. Therefore, because the front light enters the screen at a certain angle, for multi-layered LCD panels stacked vertically, the light emitted from the pixels at the edge of the lower screen on the light source side is blocked by the light-shielding area of the upper screen. This results in visual defects such as color layering and incomplete color mixing at the screen edges when the front light is on, severely affecting the overall uniformity and image quality of the displayed image. Figure 1 and 2 . Summary of the Invention

[0004] To address the technical problems existing in the background art, the present invention proposes a reflective multi-layer screen module and display device with front light.

[0005] The present invention proposes a reflective multi-layer screen module with front light, comprising: a front light module and a display module; The front light module includes a light guide plate and a supplementary light source. The display module includes an effective display area and a non-display area. The front light guide plate is located on one side of the display module, and the supplementary light source is located at the end of the front light guide plate near the non-display area, so that the light emitted from the supplementary light source is uniformly illuminated by the front light guide plate and then enters the reflective LCD panel of the display module. The display module includes a top liquid crystal panel and at least one lower liquid crystal panel. The pixel layout of the lower liquid crystal panel at the edge of the effective display area on the side of the supplementary light source is configured such that light rays from the supplementary light source directed toward the edge of the effective display area interact with corresponding pixels of the top liquid crystal panel and / or other lower liquid crystal panels within the display area, thereby achieving color mixing of the pixels of each display panel within the effective display area.

[0006] Preferably, the edge of the effective display area of the lower liquid crystal panel is provided with transition pixels, and the transition pixels are located below the non-display area of the liquid crystal panel above it.

[0007] Preferably, the transition pixel and the display pixels of the adjacent effective display area are controlled by the same circuit.

[0008] Preferably, the display pixels of at least one lower layer liquid crystal panel at the edge of the effective display area on the light source side are extended outward by a predetermined width from the outside of the effective display area.

[0009] Preferably, the preset width is determined based on at least one of the thickness of the front light guide plate, the film thickness of the display panel, and the maximum incident angle of the light from the front light module in the display layer.

[0010] Preferably, for the Nth display layer from top to bottom, the preset width L satisfies: L≥k tanC; Wherein, C is the maximum incident angle of the light from the front light module in the display layer, and k is a positive number related to the thickness of the light guide plate, the film thickness of the Nth and above display panels, and the thickness of the interlayer bonding layer.

[0011] Preferably, the configuration is as follows: the light-blocking area of at least one of the display layers at the edge of the effective display area on the light source side is moved outward by a predetermined width.

[0012] Preferably, the preset width is determined based on at least one of the thickness of the front light guide plate, the film thickness of the display panel, and the maximum incident angle of the light from the front light module in the display layer.

[0013] In this invention, the proposed reflective multi-layer screen module with front light has a front light guide plate located on one side of the display module, and a supplementary light source located at the end of the front light guide plate closer to the non-display area. This allows the light emitted from the supplementary light source to be uniformly diffused by the front light guide plate before entering the reflective liquid crystal panel. By setting transition pixels or moving the light-blocking area outward at the edge of the effective display area on the light source side of the lower screen, the large-angle incident light from the front light can be fully reflected and mixed by the corresponding pixels of each screen layer within the final effective display area. This completely eliminates the color layering phenomenon at the screen edge when the front light is on, achieving uniform color mixing across the entire area and significantly improving the overall display quality and visual effect of the display module.

[0014] The present invention also proposes a display device comprising the above-described reflective multi-layer screen module with front light.

[0015] The display device proposed in this invention has similar technical effects to the aforementioned reflective multi-layer screen module with front light, so it will not be described in detail here. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a reflective multi-layer screen module with front light in the prior art.

[0017] Figure 2 This is a schematic diagram of the optical path of a reflective multi-layer screen module with front light in the prior art.

[0018] Figure 3 This is a schematic diagram illustrating the principle of a reflective multi-layer screen module with front light proposed in this invention.

[0019] Figure 4 This is a schematic diagram of one embodiment of a reflective multi-layer screen module with front light proposed in this invention.

[0020] Figure 5 This is a schematic diagram of another embodiment of the reflective multi-layer screen module with front light proposed in this invention.

[0021] Figure 6 This is a parameter diagram of one embodiment of a reflective multi-layer screen module with front light proposed in this invention.

[0022] Figure Labels

[0023] 1. Light guide plate; 2. Supplemental light source; 3. Reflective LCD panel; 4. Cover plate. Detailed Implementation

[0024] Reference Figure 3 The present invention proposes a reflective multi-layer screen module with front light, comprising: a front light module and a display module.

[0025] The front light module includes a light guide plate 1 and a supplementary light source 2. The display module includes an effective display area and a non-display area. The front light guide plate 1 is located on one side of the display module, and the supplementary light source 2 is located at the end of the front light guide plate 1 near the non-display area, so that the light emitted from the supplementary light source 2 is uniformly distributed by the front light guide plate 1 and then enters the reflective liquid crystal panel 3.

[0026] Specifically, the light guide plate 1 is an optical material that converts a point light source or line light source into a uniform surface light source. The supplementary light source 2 can be a light-emitting diode (LED) strip. The effective display area is the area in the display module used for normal display of image content, and the non-display area is the area in the display module surrounding the effective display area that does not participate in image display. The reflective liquid crystal panel 3 is specifically a liquid crystal panel unit that uses ambient light or front light for reflective display, such as a cholesteric liquid crystal panel.

[0027] During assembly, the reflective multi-layer screen module has its front light guide plate 1 attached to one side of the display module, and the supplementary light source 2 positioned at the end of the front light guide plate 1 closest to the non-display area of the display module. When the supplementary light source 2 is lit, the light emitted enters the front light guide plate 1 from its end, and after diffusion and reflection by the microstructure inside the light guide plate 1, it is converted into a uniform surface light source and directed towards the entire display module.

[0028] The display module includes a top liquid crystal panel and at least one lower liquid crystal panel. The pixel layout of the lower liquid crystal panel at the edge of the effective display area on the side of the supplementary light source 2 is configured such that light rays from the supplementary light source 2 directed toward the edge of the effective display area interact with corresponding pixels of the top liquid crystal panel and / or other lower liquid crystal panels within the display area, thereby achieving color mixing of the pixels of each display panel within the effective display area.

[0029] The display module is composed of a top-layer liquid crystal panel and at least one lower-layer liquid crystal panel stacked together, and each layer of liquid crystal panel is a reflective liquid crystal panel 3. For the lower-layer liquid crystal panel located on one side of the supplementary light source 2, the edge pixel layout of its effective display area is specially designed. This design allows the light emitted from the supplementary light source 2 and uniformly distributed by the light guide plate 1, which then strikes the edge of the effective display area of the lower-layer liquid crystal panel at a certain angle, to interact with the pixels of the lower-layer liquid crystal panel itself, as well as the corresponding pixels of the top-layer liquid crystal panel or other lower-layer liquid crystal panels above it, within the final effective display area. This achieves complete mixing of the pixel light from each display panel within the effective display area, avoiding layering and color loss caused by light blocking.

[0030] In this embodiment, the proposed reflective multi-layer screen module with front light has a front light guide plate 1 located on one side of the display module, and a supplementary light source 2 located at the end of the front light guide plate 1 near the non-display area. This allows the light emitted from the supplementary light source 2 to be uniformly diffused by the front light guide plate 1 before entering the reflective liquid crystal panel 3. By setting transition pixels or moving the light-blocking area outward at the edge of the effective display area on the light source side of the lower screen, the large-angle incident light from the front light can be fully reflected and mixed by the corresponding pixels of each screen layer within the final effective display area. This completely eliminates the color layering phenomenon at the screen edge when the front light is turned on, achieving uniform color mixing across the entire area and significantly improving the overall display quality and visual effect of the display module.

[0031] In the specific design of the edge pixels of the lower liquid crystal panel display area, transition pixels are provided at the edge of the effective display area of the lower liquid crystal panel. The transition pixels are located below the non-display area of the liquid crystal panel above them, so that the transition pixels are set outside the normal display pixels of the effective display area and are additional pixel units used to receive large-angle incident light and display it. Specifically, these transition pixels are not used to display additional image information, but to ensure that large-angle light from the supplementary light source 2 can be effectively captured and reflected by the lower liquid crystal panel.

[0032] Taking cholesteric liquid crystal as an example, cholesteric display panels typically utilize two stable states: P-state and FC-state. The P-state reflects ambient light as the bright state, while the FC-state, in conjunction with a light-absorbing layer, serves as the dark state to achieve image display. During display, the input voltage is controlled by a circuit to change the optical state of the cholesteric liquid crystal, thereby switching between the two stable states—P-state and FC-state—and thus switching between bright and dark displays. When the entire panel is displayed, the pattern is displayed across the entire panel by controlling the input voltage of each display pixel.

[0033] In the specific control method of the transition pixel, the transition pixel and the display pixels of the adjacent effective display area are controlled by the same circuit. To achieve a simplified driving design and ensure display consistency, the driving electrodes and data lines of the transition pixel located at the edge of the effective display area are connected to the same scan lines and data lines as the first row of display pixels adjacent to it, which belong to the effective display area. During display, the driving signal received by the transition pixel and the displayed grayscale information are the same as those of the display pixels at the edge of the effective display area. This ensures that the color and brightness of the light reflected in the transition pixel area are seamlessly connected to the effective display area, preventing new brightness or color difference boundaries due to driving differences, and further optimizing the uniformity of the overall display effect.

[0034] Reference Figure 5 In one embodiment of the pixel layout at the edge of the display area, the display pixels of at least one lower liquid crystal panel display layer at the edge of the effective display area on the light source side are extended outward by a predetermined width. Specifically, when designing the pixel array of the liquid crystal panel, for the lower panel that requires transition pixels, the pixel pattern on the side of the supplementary light source 2 does not terminate at the boundary of the effective display area. Instead, it continues to extend outward of the effective display area, i.e., towards the non-display area, by an additional width. This extended pixel area constitutes the aforementioned transition pixel. Through this physical design of the outwardly extending pixel pattern, the effective area of the lower panel for reflecting light in the edge area is directly increased, so that large-angle light that would originally illuminate the non-display area and be blocked by the upper BM can now be reflected by this extended pixel and participate in color mixing.

[0035] Reference Figure 4In another embodiment of the pixel layout at the edge of the display area, the light-shielding area of at least one layer of the display layer at the edge of the effective display area on the light source side is moved outward by a predetermined width. Specifically, the light-shielding area is a black matrix area on the display layer used to block light, define pixel boundaries, and prevent light leakage. Specifically, this embodiment does not change the position and size of the pixels at the edge of the effective display area of the lower liquid crystal panel, but achieves the same purpose by adjusting the pattern design of the surrounding light-shielding area. Specifically, the boundary of the light-shielding area located on the side of the supplementary light source 2, originally adjacent to the edge of the effective display area, is moved outward by a predetermined width. After this operation, the actual reflective pixel area at the edge of the lower panel is relatively expanded inward into the effective display area, because the outward movement of the light-shielding boundary exposes more pixel area, enabling it to receive and reflect large-angle incident light from the front light. This method also achieves the purpose of expanding the effective photosensitive area at the edge of the lower panel, thereby ensuring color mixing within the display area.

[0036] As can be seen from the above, designing a preset width for the transition pixels ensures that the transition pixels are sufficient to capture all possible large-angle light rays. Therefore, the preset width is not an arbitrarily set value; its size needs to be designed and calculated to ensure that the transition pixels can completely cover all possible light paths. The determination of the preset width needs to be based on relevant optical and structural parameters. The preset width is determined based on at least one of the thickness of the front light guide plate 1, the film thickness of the display panel, and the maximum incident angle of the light from the front light module in the display layer. The main factors considered in the calculation include the thickness of the front light guide plate 1 itself, because the thickness of the light guide plate 1 affects the angle distribution of light propagation and emission within it. At the same time, the cumulative thickness of the film layers of each display panel is also crucial, because light needs to penetrate these film layers to reach the panel at different depths. In addition, the maximum incident angle of the light from the supplementary light source 2, after being homogenized by the light guide plate 1 and directed to the screen, is a key optical parameter that determines the most oblique path when the light reaches the edge of the lower panel. The preset width needs to at least cover the outermost light path determined by these thicknesses and the maximum incident angle.

[0037] In one specific implementation, the preset width can be determined as follows: For the Nth display layer from top to bottom, the preset width L satisfies: L≥k tanC; Where C is the maximum incident angle of light from the front light module in the display layer, and k is a positive number related to the thickness of the light guide plate 1, the film thickness of the Nth and above display panels, and the thickness of the interlayer bonding layer. This relationship quantitatively ensures that the preset width of the transition pixels designed for the Nth lower panel is sufficient to compensate for all lateral light path offsets caused by multi-layer stacking and oblique light incidence, thereby guaranteeing that all pixels in this layer can receive illumination and perform color mixing within the effective display area. For example, the value of k for the Nth display panel is the sum of the thickness of the light guide plate 1, the film thickness of the Nth and above display panels, and the thickness of the interlayer bonding layer.

[0038] like Figure 6 As shown, taking a blue-green-red (blue-green-red) triple-panel module as an example, the triple-panel module in this embodiment includes a blue cholesteric liquid crystal panel, a green cholesteric liquid crystal panel, and a red cholesteric liquid crystal panel stacked sequentially. Adjacent optical panels are bonded together using interlayer OCA optical adhesive. A light guide plate 1 is bonded to one side of the blue liquid crystal panel using OCA optical adhesive, and a cover plate is bonded to the side of the light guide plate 1 away from the blue liquid crystal panel using OCA optical adhesive. The thickness of the light guide plate 1 is T1, and the thickness of the front light plate OCA layer is T2. The thickness of the common substrate for each liquid crystal panel is T3, and the thickness of the array substrate is T4. The thickness of the interlayer OCA layer between adjacent liquid crystal panels is T5.

[0039] The first layer of the blue cholesteric liquid crystal panel is unaffected at the edge of the display area because it is not obstructed by the BM (bulb liner). The transition width L1 of the blue cholesteric liquid crystal panel is: L1 = 0 + (T3 + T2 + T1) tanC.

[0040] The second-layer green cholesteric liquid crystal panel is blocked by the upper blue cholesteric liquid crystal panel (BM layer), so the edge of the display area cannot reflect green light. The transition width L2 of the green cholesteric liquid crystal panel is: L2=(T4+T5+T3) tanC + (T3 + T5 + T4 + T3 + T2 + T1) tanC, That is, L2 = (T1 + T2 + 3) T3+2 T4+2 T5) tanC.

[0041] The third-layer red cholesteric liquid crystal panel is blocked by the upper green cholesteric liquid crystal panel (BM layer), so the edge of the display area cannot reflect red light. The transition width of the red cholesteric liquid crystal panel is: L3 = (T4 + T5 + T3 + T4 + T5 + T3) tanC+(T3+T5+T4+T3+T5+T4+T3+T2+T1) tanC, That is, (T1+T2+5) T3+4 T4+4 T5) tanC.

[0042] In practical design, transition pixels with a width of L3 can be set at the edges of the three effective areas, and they can be controlled by the same circuit as the first row of pixels in the effective area.

[0043] This embodiment also proposes a display device, including the aforementioned reflective multi-screen module with front illumination. Specifically, the display device can be any electronic product that requires reflective display and has front illumination function, such as electronic price tags, portable information terminals, low-power display instruments, or dual-screen display devices. After integrating the reflective multi-screen module provided by this invention as its core display component into the complete product, the display device possesses the excellent characteristics of uniform color and no layering or color mixing defects at the screen edges when front illumination is turned on, thereby improving the display quality and user experience of the complete product.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A front-lit reflective multi-stack module, characterized in that, include: Front light module and display module; The front light module includes a light guide plate and a supplementary light source. The display module includes an effective display area and a non-display area. The front light guide plate is located on one side of the display module, and the supplementary light source is located at the end of the front light guide plate near the non-display area, so that the light emitted from the supplementary light source is uniformly illuminated by the front light guide plate and then enters the reflective LCD panel of the display module. The display module includes a top liquid crystal panel and at least one lower liquid crystal panel. The effective display area edge of the at least one lower liquid crystal panel is provided with a transition pixel. The transition pixel is located below the non-display area of the liquid crystal panel above it. The transition pixel is used to allow light from the supplementary light source to be directed toward the edge of the effective display area to interact with the corresponding pixels of the top liquid crystal panel and / or other lower liquid crystal panels within the display area, so as to achieve color mixing of the pixels of each display panel within the effective display area.

2. The reflective multi-layer screen module with front light according to claim 1, characterized in that, The transition pixels and the display pixels of the adjacent effective display area are controlled by the same circuit.

3. The front lit reflective multi-stack module of claim 1 or 2, wherein, The effective display area edge of the at least one lower liquid crystal panel is provided with transition pixels, specifically: the display pixels of the display layer of at least one lower liquid crystal panel on the light source side of the effective display area edge are extended outward by a predetermined width.

4. The front lit reflective multi-stack module of claim 3, wherein, The preset width is determined based on at least one of the thickness of the front light guide plate, the film thickness of the display panel, and the maximum incident angle of the light from the front light module in the display layer.

5. The front lit reflective multi-stack module of claim 4, wherein, For the Nth layer display layer from top to bottom, the preset width L satisfies: ; Wherein, C is the maximum incident angle of the light from the front light module in the display layer, and k is a positive number related to the thickness of the light guide plate, the film thickness of the Nth and above display panels, and the thickness of the interlayer bonding layer.

6. The front lit reflective multi-stack module of claim 1 or 2, wherein, The effective display area edge of at least one lower liquid crystal panel is provided with transition pixels, specifically: the light-shielding area of the effective display area edge of at least one layer of the liquid crystal panel on the light source side is moved outward by a preset width.

7. The front lit reflective multi-stack module of claim 6, wherein, The preset width is determined based on at least one of the thickness of the front light guide plate, the film thickness of the display panel, and the maximum incident angle of light from the front light module in the display layer.

8. The front lit reflective multi-stack module of claim 1, wherein, The top and bottom LCD panels are cholesteric phase LCD panels.

9. A display device, characterized by comprising: Including the reflective multi-panel screen module with front light as described in any one of claims 1 to 8.