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KR-20260065958-A - Backlight module and display device

KR20260065958AKR 20260065958 AKR20260065958 AKR 20260065958AKR-20260065958-A

Abstract

The backlight module comprises a light guide plate (2), a light source (3), a structured optical film (4), and two prism sheets (5). The structured optical film (4) is positioned opposite the light-emitting surface (22) of the light guide plate (2) and includes a main body (41), a plurality of prisms (42) arranged in parallel on the main body (41) and facing the light-emitting surface (22), and a plurality of optical structures (43) arranged on the main body (41) and facing away from the light-emitting surface (22) of the light guide plate (2). Each prism sheet (5) is provided with a plurality of prism bars (51) arranged in parallel and facing away from the structured optical film (4), and the extension direction of the prism bar (51) on one prism sheet (5) is different from the extension direction of the prism bar (51) on the other prism sheet (5).

Inventors

  • 창, 치아-인
  • 황, 포-창
  • 린, 쿤-청

Assignees

  • 라디안트 옵토-엘렉트로닉스(쑤저우) 컴퍼니 리미티드
  • 레디언트 옵토-일렉트로닉스 코포레이션

Dates

Publication Date
20260511
Application Date
20240930
Priority Date
20231007

Claims (20)

  1. In the backlight module, A light guide plate having a light receiving surface and a light output surface connected to the light receiving surface; A light source positioned opposite the light entry surface of the light guide plate; A structured optical film disposed opposite to the light-emitting surface of the light guide plate, wherein the structured optical film comprises a main body, a plurality of prisms disposed in parallel with the main body and facing the light-emitting surface, and a plurality of optical structures disposed with the main body and facing away from the light-emitting surface of the light guide plate, wherein the prisms are located between the light-emitting surface and the optical structures; and It includes two prism sheets laminated and installed on the above-mentioned structured optical film, and A backlight module in which each of the above-mentioned prism sheets is arranged in parallel and has a plurality of prism bars facing away from the structured optical film, wherein the extension direction (E1) of the prism bar on one prism sheet is different from the extension direction (E2) of the prism bar on the other prism sheet.
  2. In paragraph 1, The above two prism sheets are a backlight module having an integrated structure.
  3. In paragraph 1, A backlight module in which the structured optical film and the prism sheet adjacent to the structured optical film are an integrated structure.
  4. In paragraph 1, A backlight module in which the above-mentioned structured optical film and the above-mentioned two prism sheets have an integrated structure.
  5. In any one of paragraphs 1 through 4, Each of the above optical structures has a centerline and a vertex, the centerline is perpendicular to the body of the structured optical film, and the vertex is located on the centerline, a backlight module.
  6. In paragraph 5, Each of the above-mentioned optical structures further comprises a plurality of sides surrounding the centerline, and each of the above-mentioned sides is a composite surface formed by joining two or more layers of surface units along the extension direction of the centerline, and each of the above-mentioned surface units has a normal, and the angle between the normal of the surface unit of the same layer surrounding the centerline and the centerline is the same, and the angle between the normal of the surface unit of another layer along the centerline and the centerline is different, a backlight module.
  7. In paragraph 6, A backlight module in which the angle between the normal and the centerline of the face unit near the vertex is smaller than the angle between the normal and the centerline of the face unit far from the vertex.
  8. In any one of paragraphs 1 through 4, It further includes a reflective reflective sheet located below the light guide plate, A backlight module in which the prism angle of the prism of the structured optical film and the roughness ratio of the reflective reflective sheet are between 700 and 900 and include both end values.
  9. In paragraph 8, A backlight module in which the prism angle of the prism of the structured optical film is between 70° and 90° and includes both end values, and the roughness of the reflective reflective sheet is 0.1.
  10. In any one of paragraphs 1 through 4, It further includes a diffuse reflective sheet located below the light guide plate, A backlight module in which the prism angle of the prism of the structured optical film and the roughness ratio of the diffuse reflective sheet are greater than 200 and less than or equal to 250.
  11. In Paragraph 10, A backlight module in which the prism angle of the prism of the structured optical film is greater than 80° and less than or equal to 100°, and the roughness of the diffuse reflective sheet is 0.4.
  12. In any one of paragraphs 1 through 4, A backlight module in which the ratio of the refractive index of the prism sheet to the refractive index of the structured optical film is 1.08 or higher.
  13. In any one of paragraphs 1 through 4, A backlight module in which the refractive index of the prism sheet is 1.62 and the refractive index of the structured optical film is 1.55.
  14. In any one of paragraphs 1 through 4, There is a non-zero angle (θ) between the prism of the structured optical film and the prism bar on one of the prism sheets, and There is a prism spacing (T1) between each of two adjacent prisms, and a prism bar spacing (T2) between each of two adjacent prism bars, and These prisms and these prism bars are combined to form multiple moiré stripes, and there is a moiré stripe spacing (P) between each of two adjacent moiré stripes, and the moiré stripe spacing (P) is, Relationship P= Satisfying, A backlight module in which the above moiré stripe spacing (P) is less than 250㎛.
  15. In any one of paragraphs 1 through 4, The light guide plate further comprises a bottom surface on the opposite side of the light-emitting surface and a plurality of light guide structures formed on the bottom surface, and Each of the above-mentioned light guide structures comprises a light-receiving surface and a light-receiving surface connected to each other, wherein the light-receiving surface faces the direction of light propagation of the light source, a light-receiving angle is formed between the light-receiving surface and the bottom surface, and the light-receiving angle is 20° or less, a backlight module.
  16. In paragraph 5, A backlight module wherein the main body of the structured optical film has a first surface facing away from the light-emitting surface of the light guide plate, the optical structure is disposed on the first surface, the first surface has a plurality of upwardly convex arc surface regions, and a plurality of the optical structures are disposed within each of the arc surface regions.
  17. In Paragraph 16, A backlight module in which the centerlines of a plurality of optical structures within each of the above-mentioned arc surface regions are not parallel to each other.
  18. In paragraph 1, A backlight module in which at least one of the height of the prism of the structured optical film, the height of the optical structure, and the height of the prism bar of the prism sheet is randomly distributed.
  19. In paragraph 1, Each of the above prism sheets has a first edge and a second edge perpendicular to each other, and A backlight module in which a first angle (α1) is formed between the extension direction (E1) of the prism bar of one of the two prism sheets and the first edge, and a second angle (α2) is formed between the extension direction (E2) of the prism bar of the other prism sheet and the second edge.
  20. In Paragraph 18, A backlight module having at least one of the first angle (α1) and the second angle (α2) not 0, with an absolute value between 3° and 5° and including both end values.

Description

Backlight module and display device This application claims priority to Chinese patent application No. 2023112841810, filed on October 7, 2023, with the invention title "Backlight module and display device," the entire contents of said application incorporated by reference into this application. The present invention relates to optical equipment, and in particular to a backlight module and a display device. Conventional backlight modules generally use diffusion sheets to homogenize light. Currently, commonly used diffusion sheets are equipped with multiple scattering particles, which homogenize light by scattering the light to cause it to be dispersed and emitted. However, diffusion sheets equipped with such scattering particles are generally used for covering purposes and have low optical directivity, which degrades the high directivity of the light guide plate. Therefore, to increase directivity, the haze of the diffusion sheet must be reduced, which leads to a deterioration in the covering effect. While brightness enhancement films are advantageous for improving brightness, the haze of the upper and lower diffusion sheets used in backlight modules affects brightness and optical appearance, making it difficult to further improve the luminance of existing backlight modules. Consequently, the key design issue for backlight modules has become how to increase the light concentration, rotation, and directivity of the light emission viewing angle while maintaining coverage capability. Therefore, the objective of the present invention is to provide a backlight module that improves the light concentration, rotation, and directionality of the light emission viewing angle. The backlight module of the present invention comprises a light guide plate, a light source, a structured optical film, and two prism sheets. The light guide plate has an incoming light surface and an outgoing light surface connected to the incoming light surface. The light source is positioned opposite the incoming light surface of the light guide plate. The structured optical film is positioned opposite the outgoing light surface of the light guide plate and includes a main body, a plurality of prisms arranged parallel to the main body and facing the outgoing light surface, and a plurality of optical structures arranged on the main body and facing away from the outgoing light surface of the light guide plate. Here, the prisms are located between the outgoing light surface and the optical structures. Two prism sheets are laminated and installed on the structured optical film. Each prism sheet has a plurality of prism bars arranged parallel to and facing away from the structured optical film, and the extension direction of the prism bars on one prism sheet is different from the extension direction of the prism bars on the other prism sheet. Another objective of the present invention is to provide a display device comprising a backlight module and a display panel disposed on the backlight module. The effect of the present invention is that light rays emitted from a light source first pass through the prismatic pillars of a structured optical film to improve directivity, and then, through the optical structure of the structured optical film, energy is concentrated at the positions spectrally separated by the prismatic pillars while maintaining a coverage effect. As a result, the structured optical film can allow light rays to be concentrated and emitted while maintaining coverage ability, and finally, by using two prism sheets to intensively concentrate spectrally concentrated energy, the light concentration and brightness of the backlight module are improved. FIG. 1 is a three-dimensional exploded view of a preferred embodiment of the backlight module of the present invention. Figure 2 is a side schematic diagram that supplementarily explains Figure 1 from a side viewing angle. Figure 3a is an enlarged schematic diagram of the part indicated by the circle in Figure 2. FIG. 3b is a schematic diagram illustrating another embodiment different from FIG. 3a. FIG. 3c is a schematic diagram illustrating another embodiment different from FIG. 3a. FIG. 3d is a schematic diagram illustrating another embodiment different from FIG. 3a. Figure 4 is a graph illustrating the relationship between the refractive index ratio and luminance of a prism sheet and a structured optical film. Figure 5 is a graph illustrating the relationship between the prism angle of a structured optical film and the roughness ratio and luminance of a reflective reflective sheet. Figure 6 is a side schematic diagram illustrating the case where a different type of reflective sheet is used in the backlight module. Figure 7 is a graph illustrating the relationship between the prism angle of a structured optical film and the roughness ratio and luminance of a diffuse reflective sheet. FIG. 8 is a side schematic diagram illustrating that a plurality of light guide structures are formed on the