Light-condensing auxiliary film, side-light-type backlight unit on which light-condensing auxiliary film is mounted, and liquid crystal display device on which side-light-type backlight is mounted

By using a light-focusing auxiliary film in side-lit backlights, the problems of light propagation mismatch and moiré patterns were solved, improving the brightness and uniformity of the backlights and reducing production costs, thus enabling low-cost mass production.

CN121693693APending Publication Date: 2026-03-17INTELLIGENT SEMICONDUCTOR CORP
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Patent Information

Application Number
CN202480052374.X
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Priority Date
2023-08-10
Filing Date
2024-06-18
Publication Date
2026-03-17

AI Technical Summary

Technical Problem

In existing side-lit backlights, the propagation direction and shape of light after it is emitted from the light guide plate are not optimally matched with the brightness enhancement film, resulting in large scattering loss during light propagation and insufficient brightness on the front of the backlight. Furthermore, existing optical films have moiré patterns, making it difficult to mass-produce them at low cost.

Method used

A light-concentrating auxiliary film is designed and inserted between a light guide plate and a brightness enhancement film. A light-transmitting substrate film is used as the light waveguide layer, the light extraction layer has an inverted quadrangular pyramidal concave part, and the light guiding layer has a parallel triangular prism. By controlling the spacing and refractive index relationship between the concave part and the prism, the use of light-diffusing particles is avoided, and the light concentration and angle change are achieved. It is suitable for roll-to-roll production.

Benefits of technology

It improves the front brightness and brightness uniformity of the backlight, reduces manufacturing costs, avoids the visual recognition of moiré patterns, and is suitable for mass production.

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Abstract

Provided is an optical film requirement that does not use fine particles for light diffusion, is entirely composed of a transparent resin, and has a self-moire pattern that cannot be visually recognized by the naked eye, said optical film requirement having high front brightness without luminance unevenness on the light emission surface of a backlight when mounted on an edge-light backlight. A light-collecting auxiliary film inserted between the light emission surface of a light guide plate and the light incidence surface of a brightness enhancement film (BEF) in an edge-light backlight unit using discrete LED point light sources, the light-collecting auxiliary film being characterized by comprising: an optical waveguide layer comprising a light-transmitting base film, and a light-collecting layer comprising a light-transmitting base film, the light-collecting auxiliary film being interposed between the light emission surface of the light guide plate and the light incidence surface of the brightness enhancement film (BEF), the light-collecting auxiliary film being interposed between the light-emitting surface of the light guide plate and the light incidence surface of the brightness enhancement film (BEF); a light extraction layer that is formed on one surface of the optical waveguide layer and has a plurality of inverted rectangular pyramid-shaped unit recesses; and a light introduction layer formed on the other surface of the optical waveguide layer and having a plurality of unit triangular prisms extending in parallel in one direction, the light extraction layer constituting a light emission surface, and prism surfaces of the plurality of unit triangular prisms constituting the light introduction layer constituting a light incidence surface. The direction of the ridge lines of the plurality of unit recesses and the direction of the ridge lines of the plurality of unit triangular prisms intersect at an angle of 42 DEG to 48 DEG, and the light extraction layer, the optical waveguide layer, and the light introduction layer do not contain fine particles for light diffusion. The self-moire pattern generated by the plurality of unit recesses and the plurality of unit triangular prism lenses cannot be visually recognized by naked eyes.
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