Optical sheet for liquid crystal display apparatus and backlight unit using the same

Abstract

The objective of the invention is to provide an optical sheet for liquid crystal display apparatus and a backlight unit suing the same. The optical sheet for liquid crystal display apparatus has excellent optical functions, specifically optical diffusion function; the backlight unit optimizes visual field angle, removes lamp source images, becomes thinner, and also hoists the like qualities. The invention is an optical sheet for liquid crystal display apparatus, which has a transparent substrate layer and a microlens array, wherein the microlens array is composed of a plurality of microlens formed by the substrate surface and back face, wherein the back microlens can be a concave lens, the back microlens array is preferably composed of a plurality of microlens with random diameter, the average radius of the surface microlens can be from 3[mu]m to 90[mu]m. In addition, the average radius of the back microlens is from 2[mu]m to 10[mu], and is about 1 / 12 to 1 of the average radius of thesurface microlens.

Description

technical field [0001] The present invention relates to an optical sheet having various functions such as condensing light, light diffusing, and refracting light toward a normal direction, and is especially suitable for a backlight unit of a liquid crystal display device, and a backlight unit using the optical sheet. Background technique [0002] A liquid crystal display device generally adopts a backlight method in which the liquid crystal layer is irradiated from the back, and an edge-light type (side-light type), direct-light type, or other backlight unit is installed on the lower side of the liquid crystal layer. The edge light type backlight unit 40 is generally as follows Figure 9a As shown, it includes: a rod-shaped light source 41 as a light source, a square plate-shaped light guide plate 42 arranged along the light source 41 at its end, and a plurality of optical discs laminated on the surface side of the light guide plate 42 . Sheet 43. The optical sheet 43 has s...

AI Technical Summary

Problems solved by technology

[0006] However, the optical functions of the microlens sheet, such as light gathering, light diffusion, and angle change, are determined by the surface shape and refractive index, so it has a certain effect on improving the performance. a certain limit

In particular, in direct-lit backlights, if the light diffusion function of the optical sheet is insufficient, the effect of erasing the light source image is small, so there is a disadvantage that the light source image appears on the surface of the liquid crystal screen.

Therefore, although the conventional backlight unit 40 is expensive and difficult to handle, it is still necessary to have a plurality of optical sheets.

In addition to the disadvantage of lowering the brightness of the liquid crystal display device, the situation of having a plurality of optical sheets as described above also hinders the thinning of the backlight unit.

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