An optical cavity assembly suitable for zone color tuning

Abstract

This invention provides an optical cavity assembly suitable for zoned color adjustment, including a diffuser sheet with a regularly arranged array of black matrix units of equal size and spacing. A three-primary-color tunable light source within a backlight zone and the diffuser sheet with black matrix units constitute an optical cavity structure without a physical grid, allowing for constraint on the shape of the light spot. The optical cavity corresponds one-to-one with the backlight zone, and the size of the black matrix units on the diffuser sheet matches the size of the backlight zone. By evaluating the light emission effect of the diffuser sheet, the distance h between the diffuser sheet and the light source, the shape and structure of the black matrix units, and specific parameters within the optical cavity structure are adjusted and determined. Applying this technical solution can improve the uniformity of color and brightness within the backlight zone and reduce crosstalk in light color and brightness between backlight zones.

Description

Technical Field

[0001] This invention relates to the field of display optics technology, and in particular to an optical cavity assembly suitable for zoned color adjustment. Background Technology

[0002] Traditional LCD backlight systems use a single global backlight source to illuminate the entire screen. However, this design has limitations in displaying both bright and dark details, leading to loss of dark details and reduced contrast.

[0003] Local dimming backlighting is a backlight adjustment technology used in LCD displays. This technology divides the backlight into multiple independent zones, each with individually adjustable brightness and color. By flexibly controlling these backlight zones, higher contrast, a wider color gamut, and more detailed color reproduction can be achieved. Local dimming backlighting technology can precisely adjust the backlight brightness of each zone according to the content of the image. When only a portion of the image needs to display bright details, other areas can maintain lower backlight brightness or even be completely off, thus providing higher contrast and deeper shadow details, further enhancing image quality.

[0004] The main technical challenges in implementing backlight-local color-tuned LCD panels lie in designing intricate backlight zones and corresponding driving circuits, as well as providing a more efficient backlight source. By precisely controlling the backlight intensity and color output of each zone, bright areas and dark details can be displayed simultaneously on the same screen, improving image quality and the viewing experience.

[0005] Existing local dimming technology based on liquid crystal backlighting requires simultaneous dimming and color adjustment within each backlight zone, and the addition of a metal physical grid between zones to prevent crosstalk between different colors and intensities of light. This necessitates precise alignment of the liquid crystal pixels with the local dimming grid; even the slightest deviation can affect the display effect. Furthermore, the selection, manufacturing difficulty, and cost of the local dimming grid also pose challenges to this technology. Choosing a suitable grid material requires consideration of factors such as optical performance, stability, and manufacturing cost, while existing processing methods are often complex and expensive. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide an optical cavity assembly suitable for zoned color tuning, which improves the uniformity of color and brightness within the backlight zone and reduces crosstalk between backlight zones in terms of color and brightness.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: an optical cavity assembly suitable for zoned color adjustment, comprising a diffuser sheet, on which a black matrix array of equal size and spacing is regularly arranged. The three primary color tunable light source in the backlight zone and the diffuser sheet with black matrix form an optical cavity structure without physical grid and constraining the shape of the light spot; wherein, the optical cavity corresponds one-to-one with the backlight zone, and the size of the black matrix unit on the diffuser sheet is consistent with the size of the backlight zone; by evaluating the light emission effect of the diffuser sheet, the distance h between the diffuser sheet and the light source, the shape and structure of the black matrix unit, and specific parameters in the optical cavity structure are adjusted and determined.

[0008] In a preferred embodiment, the key structural parameters of the optical cavity formed by the diffuser sheet, black matrix, and RGB mini-LED light source corresponding to the liquid crystal backlight partition satisfy the following expression:

[0009]

[0010] Where h is the distance between the diffuser and the RGB mini-LED light source, L is the length of the backlight zone, d is the width of the black matrix unit, a is the thickness of the diffuser, θ is the Lambertian limit angle of the RGB mini-LED light source, and θ' is the refraction angle of the light after entering the diffuser.

[0011] In a preferred embodiment, the method for determining the lower limit h1 of the distance between the diffuser integrating black matrix units and the RGB mini-LED light source is as follows: the condition for achieving the lower limit of the distance between the diffuser and the RGB mini-LED light source is that the circular illumination area of ​​the light-emitting surface of the diffuser is tangent to the backlight sub-partition, and the light overflowing from the backlight sub-partition is exactly absorbed and blocked by the black matrix units distributed on the diffuser; the lower limit h1 is determined according to the following expression:

[0012]

[0013] When the LCD panel is determined and the line width d of the black matrix units distributed on the diffuser is consistent with the line width of the black matrix between the LCD pixels, if the backlight source is also determined, then the lower limit h1 of the distance between the diffuser and the RGB mini-LED light source is affected by the size L of the backlight partition and the thickness a of the diffuser; where the value range of a is [0.001mm-1mm].

[0014] In a preferred embodiment, the upper limit h2 of the distance between the diffuser plate integrating the black matrix unit and the RGB mini-LED light source is determined as follows: The upper limit h2 of the distance between the diffuser plate and the RGB mini-LED light source is determined according to the following expression:

[0015]

[0016] When the LCD panel is determined, and the line width d of the black matrix units distributed on the diffuser is consistent with the line width of the black matrix between the LCD pixels, if the backlight source is also determined, then the upper limit h2 of the distance between the diffuser and the RGB mini-LED light source is only affected by the size L of the backlight partition.

[0017] In a preferred embodiment, the black matrix unit is designed on the light-incident surface, the light-exit surface, or embedded in the diffuser sheet according to the size of the backlight partition;

[0018] When the black matrix unit is designed on the light-emitting surface of the diffuser, the width d of the black matrix unit is determined according to the following expression:

[0019]

[0020] When the black matrix element is designed on the light-incident surface of the diffuser, if the diffuser thickness a = 0 in the above formula set, then the width of the black matrix element is determined according to the following expression:

[0021]

[0022] In a preferred embodiment, the width of the black matrix unit on the surface of the diffuser sheet is in the range of [d1, d2].

[0023] The lower limit d1 of the width of the black matrix unit is determined according to the following expression:

[0024]

[0025] The upper limit d2 of the width of the black matrix cell is determined according to the following expression:

[0026]

[0027] In a preferred embodiment, the shape of the black matrix unit that realizes the grid replacement function is not limited to a rectangle; when the liquid crystal pixel unit is not rectangular, the black matrix unit is changed to a honeycomb or circular shape accordingly.

[0028] 1) When the shape of the black matrix unit is a honeycomb polygon, its width d is determined according to the following expression:

[0029] d = h × tanθ + a × tanθ' - L

[0030] Where h is the distance between the diffuser and the RGB mini-LED light source, θ is the Lambertian limit angle of the RGB mini-LED light source, θ' is the refraction angle of the light after entering the diffuser, a is the thickness of the diffuser, and L is the center distance of the inscribed regular polygon backlight partition.

[0031] 2) When the shape of the black matrix unit is circular, its width d is determined according to the following expression:

[0032] d = h × tanθ + a × tanθ' - R

[0033] Where h is the distance between the diffuser and the RGB mini-LED light source, θ is the Lambertian limit angle of the RGB mini-LED light source, θ' is the refraction angle of the light after entering the diffuser, a is the thickness of the diffuser, and R is the radius of the circular backlight zone.

[0034] In a preferred embodiment, the crosstalk evaluation index η of the low-color crosstalk diffuser structure integrating black matrix units is defined as the radiant flux of the circular illumination region of the diffuser. Radiant flux of backlight zones The difference accounts for a portion of the radiant flux in the circular illumination area of ​​the diffuser. The percentage, and the range of η is [0, 3%];

[0035] When the black matrix unit is designed on the light-incident surface of the diffuser, η is determined according to the following set of expressions:

[0036]

[0037] In this context, the RGB mini-LED light source is considered as a Lambertian radiation source. Let I0 be the radiation intensity described in spherical coordinates, θ2 be the Lambertian limit angle of the RGB mini-LED light source, θ1 be the angle between the surface normal of the RGB mini-LED light source and the light rays passing through the edge of the backlight partition, h be the distance between the diffuser and the RGB mini-LED light source, d be the width of the black matrix unit, and L be the length of the backlight partition.

[0038] In a preferred embodiment, the light source type of the optical cavity light guide structure is not limited to LED light sources with adjustable R / G / B respectively; for large or ultra-large size liquid crystal display devices, the light source in the backlight zone adopts a miniature side-lit / direct-lit three-color LCD backlight or a planar light source such as a three-color OLED, so as to improve the overall light emission uniformity of the backlight zone and reduce color crosstalk between the zones.

[0039] In a preferred embodiment, the high-efficiency light-gathering structure in the optical cavity adds a cup-shaped reflective optical structure at the bottom of the light source in the optical cavity to collect the light emitted by the light source in all directions and converge the light upwards, so as to effectively improve the light utilization rate of the backlight zone.

[0040] The height y and the bottom radius x of the circular cup-shaped reflective optical structure are determined according to the following set of expressions:

[0041]

[0042] Where h is the distance between the diffuser and the RGB mini-LED light source, L is the length of the backlight zone, d is the width of the black matrix unit, θ is the Lambertian limit angle of the RGB mini-LED light source, and α is the incident angle of the light path e2; where the value range of d is [0mm-10mm] and the value range of L is [0mm-1000mm].

[0043] The high-efficiency light-concentrating structure includes a cup-shaped reflective optical structure, as well as conical and elliptical structures with light-concentrating functions.

[0044] Compared with existing technologies, this invention has the following advantages: This invention proposes an optical cavity structure suitable for liquid crystal zone color adjustment that eliminates the need for a grid. In a direct-lit backlight module, the black matrix unit is designed on the light-incident surface of the diffuser according to the size of the backlight zone, and the light source corresponding to each backlight zone is an RGB mini-LED light source with adjustable brightness of the three primary colors. Its angular distribution of emissivity is a Lambertian distribution, and its spatial distribution is uniform. By reasonably adjusting the distance between the diffuser and the RGB mini-LED light source, as well as the light guide cavity structure parameters between them, zone isolation is achieved while eliminating the grid, thereby improving the uniformity of color and brightness within the backlight zone and reducing crosstalk between backlight zones in terms of light color and brightness. Attached Figure Description

[0045] Figure 1 The black matrix partitioned diffuser and light guide structure are preferred embodiments of the present invention.

[0046] Figure 2 This is a schematic diagram of the adjacent optical cavity structure of a preferred embodiment of the present invention.

[0047] Figure 3 This is a schematic diagram of the optical cavity structure of the honeycomb backlight partition in a preferred embodiment of the present invention.

[0048] Figure 4 This is a schematic diagram of the optical cavity structure of the circular backlight partition in a preferred embodiment of the present invention.

[0049] Figure 5 This is a schematic diagram illustrating the calculation of crosstalk evaluation index according to a preferred embodiment of the present invention.

[0050] Figure 6 This is a schematic diagram of a circular cup-shaped reflective optical cavity structure according to a preferred embodiment of the present invention.

[0051] Figure 7This is a schematic diagram of the optical paths e1 and e2 in a preferred embodiment of the present invention. Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0053] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0054] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application; as used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise; furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0055] refer to Figure 1-7 This invention proposes an optical cavity assembly suitable for zoned color adjustment. In a direct-lit backlight module, a black matrix array of equal size and spacing is regularly arranged on a diffuser. The three primary color tunable light sources within the backlight zones and the diffuser with black matrices constitute an optical cavity structure without physical grids and capable of constraining the shape of the light spot. The optical cavity corresponds one-to-one with the backlight zones, and the size of the black matrix units on the diffuser is consistent with the size of the backlight zones. By evaluating the light emission effect of the diffuser, the distance between the diffuser and the RGB mini-LED light source, as well as the light guide cavity structure parameters between them, are adjusted and determined. This achieves zoned isolation while removing the grid, thereby improving the uniformity of color and brightness within the backlight zones and reducing crosstalk in light color and brightness between backlight zones.

[0056] Example 1:

[0057] When using a partitioning method with 64 horizontal sub-partitions and 36 vertical sub-partitions, totaling 2304 backlight sub-partitions, each backlight sub-partition is a square with a side length L = 10.9 mm, corresponding to a 30*30 pixel area on the LCD panel. The angular distribution model of the LED light source radiance corresponding to the backlight sub-partitions is the Lambertian distribution model, with the Lambertian limit angle θ = 60° for the RGB mini-LED light source; the width of the black matrix unit d = 0.1 mm; the value range of the diffuser thickness a is [0.001 mm - 1 mm]; and the refraction angle θ' of light after entering the diffuser is 75°.

[0058] When the black matrix units are designed on the light-emitting surface of the diffuser, the circular illumination area of ​​the diffuser's light-emitting surface tangents to the backlight sub-region. At this time, the light overflowing from the backlight sub-region is absorbed and blocked by the black matrix units distributed on the diffuser. Therefore, the lower limit h1 of the distance between the diffuser and the RGB mini-LED light source is determined according to the following expression:

[0059]

[0060] When the LCD panel is determined, and the line width d of the black matrix units distributed on the diffuser is consistent with the line width of the black matrix between the LCD pixels, if the backlight source is also determined, then the lower limit h1 of the distance between the diffuser and the RGB mini-LED light source is affected by the size L of the backlight partition and the thickness a of the diffuser. The range of values ​​for the lower limit h1 of the distance between the diffuser and the RGB mini-LED light source is [1.050mm-3.202mm].

[0061] When the black matrix unit is designed on the light-incident surface of the diffuser, if the diffuser thickness a = 0 in the above formula, then...

[0062] The upper limit h2 of the distance between the diffuser and the RGB mini-LED light source is determined according to the following expression:

[0063]

[0064] When the LCD panel is fixed, and the line width d of the black matrix units distributed on the diffuser is consistent with the line width of the black matrix between the LCD pixels, then if the backlight source is also fixed, the upper limit h2 of the distance between the diffuser and the RGB mini-LED light source is only affected by the size L of the backlight partition. Therefore, the upper limit h2 of the distance between the diffuser and the RGB mini-LED light source is 3.204 mm.

[0065] Example 2:

[0066] When the black matrix unit is designed on the light-incident surface of the diffuser, the crosstalk evaluation index η is determined according to the following set of expressions:

[0067]

[0068] In this context, the RGB mini-LED light source is considered as a Lambertian radiation source. Let I0 be the radiant intensity described in spherical coordinates, where I0 is the radiant intensity along the normal direction of the RGB mini-LED light source surface, h = 3.204 mm is the distance between the diffuser and the RGB mini-LED light source, d = 0.1 mm is the width of the black matrix unit, L = 10.9 mm is the length of the backlight zone, θ2 = 60° is the maximum single-sided emission angle of the RGB mini-LED light source centered on the normal, θ1 = 59.55° is the angle between the normal to the RGB mini-LED light source surface and the light rays passing through the edge of the backlight zone, and the radiant flux of the circular illumination area of ​​the diffuser. Radiant flux of backlight zones Crosstalk evaluation index η < 0.89%.

[0069] Example 3:

[0070] A cup-shaped reflective optical structure is added to the bottom of the light source inside the optical cavity. Its height y and bottom radius x are determined according to the following set of expressions:

[0071]

[0072] Where h is the distance between the diffuser and the RGB mini-LED light source, L is the length of the backlight zone, d is the width of the black matrix unit, θ is the Lambertian limit angle of the RGB mini-LED light source, and α is the incident angle of the light path e2. The value range of d is [0mm-10mm], and the value range of L is [0mm-1000mm].

[0073] When the height of the round cup At that time, the key parameters for obtaining the round cup are:

[0074]

[0075] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An optical cavity assembly suitable for zoned color adjustment, characterized in that: The system includes a diffuser sheet with regularly arranged black matrix arrays of equal size and spacing. A three-primary-color tunable light source within a backlight zone and the diffuser sheet with black matrices constitute an optical cavity structure without a physical grid, allowing for constraint on the shape of the light spot. The optical cavity corresponds one-to-one with the backlight zone, and the size of the black matrix units on the diffuser sheet matches the size of the backlight zone. By evaluating the light emission effect of the diffuser sheet, the distance h between the diffuser sheet and the light source, the shape and structure of the black matrix units, and specific parameters within the optical cavity structure are adjusted and determined. The key structural parameters of the optical cavity formed by the diffuser, black matrix, and RGB mini-LED light source corresponding to the liquid crystal backlight partitions satisfy the following expression: in, L is the distance between the diffuser and the RGB mini-LED light source, L is the length of the backlight zone, and d is the line width of the black matrix unit. For the thickness of the diffuser sheet, The Lambertian limit angle for RGB mini-LED light sources. The angle of refraction of light after it enters the diffuser; Lower limit of the distance between the diffuser plate integrating the black matrix unit and the RGB mini-LED light source The method for determining the distance between the diffuser and the RGB mini-LED light source is as follows: the circular illumination area of ​​the diffuser's light-emitting surface is tangent to the backlight sub-zone, and the light overflowing from the backlight sub-zone is precisely absorbed and blocked by the black matrix units distributed on the diffuser; the lower limit Determine based on the following expression: When the LCD panel is determined, and the line width d of the black matrix units distributed on the diffuser is consistent with the line width of the black matrix between the LCD pixels, if the backlight source is also determined, then the lower limit h1 of the distance between the diffuser and the RGB mini-LED light source is determined by the length L of the backlight partition and the thickness of the diffuser. Impact; among them, The value range is [0.001mm-1mm]; The black matrix unit is designed according to the size of the backlight partition on the light-incident surface of the diffuser, the light-outceasing surface, or embedded in the diffuser. When the black matrix unit is designed on the light-emitting surface of the diffuser, the line width d of the black matrix unit is determined according to the following expression: When designing black matrix units on the light-incident surface of the diffuser, the thickness of the diffuser is set in the above formula group. If the line width of the black matrix cell is 0, then the line width of the black matrix cell is determined according to the following expression: 。 2. The optical cavity assembly suitable for zoned color adjustment according to claim 1, characterized in that, Maximum distance between the diffuser plate integrating the black matrix unit and the RGB mini-LED light source Method for determining: Upper limit of distance between diffuser and RGB mini-LED light source Determine based on the following expression: When the LCD panel is determined, and the line width d of the black matrix units distributed on the diffuser is consistent with the line width of the black matrix between the LCD pixels, then, if the backlight source is also determined, the upper limit of the distance between the diffuser and the RGB mini-LED light source is... It is only affected by the size L of the backlight zone.

3. An optical cavity assembly suitable for zoned color adjustment according to claim 1, characterized in that, The line width of the black matrix cells on the diffuser surface ranges from [ , ]; Among them, the lower limit of the line width of the black matrix unit. Determine based on the following expression: Upper limit of line width for black matrix cells Determine based on the following expression: 。 4. An optical cavity assembly suitable for zoned color adjustment according to claim 1, characterized in that, When the liquid crystal pixel unit is not rectangular, the black matrix unit is changed to a honeycomb or circular shape accordingly; 1) When the shape of the black matrix unit is a honeycomb polygon, its width d is determined according to the following expression: Where h is the distance between the diffuser and the RGB mini-LED light source. The Lambertian limit angle for RGB mini-LED light sources. The angle of refraction of light after it enters the diffuser. 1) The thickness of the diffuser sheet; 2) When the shape of the black matrix unit is circular, its width d is determined according to the following expression: Where h is the distance between the diffuser and the RGB mini-LED light source. The Lambertian limit angle for RGB mini-LED light sources. The angle of refraction of light after it enters the diffuser. R is the thickness of the diffuser sheet, and R is the radius of the circular backlight section.

5. An optical cavity assembly suitable for zoned color adjustment according to claim 1, characterized in that, Crosstalk evaluation index for low-color crosstalk diffuser structure integrating black matrix units Defined as the radiant flux of the circular illumination region of the diffuser. Radiant flux of backlight zones The difference accounts for a portion of the radiant flux in the circular illumination area of ​​the diffuser. The percentage, and The value range is [0, ]; When the black matrix unit is designed on the incident surface of the diffuser sheet Determine based on the following group of expressions: In this context, the RGB mini-LED light source is considered as a Lambertian radiation source. Let be the radiation intensity described in spherical coordinates. The radiation intensity along the normal direction of the RGB mini-LED light source surface. The Lambertian limit angle for RGB mini-LED light sources. h is the angle between the surface normal of the RGB mini-LED light source and the light rays passing through the edge of the backlight partition. Distance, d is the line width of the black matrix unit, and L is the length of the backlight zone.

6. An optical cavity assembly suitable for zoned color adjustment according to claim 1, characterized in that, A circular cup-shaped reflective optical structure is added to the bottom of the light source inside the optical cavity to collect the light emitted from the light source in all directions and converge the light upwards, so as to effectively improve the light utilization rate of the backlight zone. The height y and the bottom radius x of the circular cup-shaped reflective optical structure are determined according to the following set of expressions: in, L is the distance between the diffuser and the RGB mini-LED light source, L is the length of the backlight zone, and d is the line width of the black matrix unit. The Lambertian limit angle for RGB mini-LED light sources. Let be the incident angle of the light path; where d ranges from 0mm to 10mm and L ranges from 0mm to 1000mm.

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