CN100395616C - Concentrating sheet and backlight module using the same - Google Patents

Abstract

The invention discloses a backlight module, which includes a light source, a reflection sheet, a light guide plate, a diffusion sheet and a light concentrating sheet, wherein the light source is located on one side of the light guide plate, and the reflection sheet, light guide plate, and diffusion sheet The condensing sheets are placed in sequence, the condensing sheet includes a light incident surface for receiving light, a light exit surface opposite to the light incident surface, the light exit surface has a Fresnel lens array, and the Fresnel lens array and The condensing sheet is an integral structure.

Description

Concentrating sheet and backlight module using the same

【Technical field】

The invention relates to a condensing sheet and a backlight module using the condensing sheet, in particular to a condensing sheet for a liquid crystal display and a backlight module using the condensing sheet.

【Background technique】

The condensing sheet is an important component in the backlight module. As shown in Figure 1, the condensing sheet 15, the light source 11, the reflector 12, the light guide plate 13 and the diffusion sheet 14 are combined to form the backlight module 1, which does not emit light by itself. The liquid crystal panel provides lighting, so that the liquid crystal panel can achieve the display effect. The condensing sheet 15 is a condensing device, the condensing sheet 15 mainly includes a light incident surface (not marked) and a light exit surface (not marked), its function is to refract the light diffused by the diffuser 14, Concentrate the dispersed light in a certain angle range and emit it to the liquid crystal panel, thereby improving the brightness of the lighting.

A prior art concentrating sheet can refer to International Patent Application No. WO96/23649 published on August 8, 1996. As shown in FIG. 2 , the concentrating sheet 20 includes a substrate 21 on which Form several fine strips 22 by pouring the mold, and carry out baking and curing treatment on the light concentrating sheet 20 to fix the fine strips 22, and carry out heat treatment on the light concentrating sheet 20, wherein the temperature of the heat treatment is at least equal to the glass transition of the resin The heat treatment increases the glass transition temperature of the epoxy by about 300K, thereby reducing the influence on the shape of the light-concentrating teeth formed by the fine strips 22 .

However, the fine strips 22 of the condensing sheet 20 can only condense the light in a single direction. The light spotting effect is not ideal.

For another prior art concentrating sheet, please refer to Chinese Patent No. 01200551 published on November 28, 2001. As shown in FIG. Wherein, the fine hemispherical layer 352 is made of an epoxy substance, and when the filling mold of the fine hemispherical layer 352 is formed and not cured, the upper surface of the substrate 351 is pasted on the bottom of the fine hemispherical layer 352 On the surface, a light collecting sheet 35 is formed. Thus, the upper surface of the fine hemispherical layer 352 and the bottom surface of the substrate 351 jointly form the upper surface 355 and the bottom surface 354 of the light concentrating sheet. The fine hemispherical layer 352 is composed of hemispherical fine hemispherical 353 arranged.

When light enters the light-condensing sheet 35 through the bottom surface 354 of the light-condensing sheet 35, and passes through the fine hemispherical layer 352, the light is refracted and concentrated by the arc surface of the fine hemisphere 353, so that the light on the light-condensing sheet 35 The light on surface 355 exhibits a preferred brightness.

However, the condensing sheet 35 is formed by pasting the upper surface of the substrate 351 on the bottom surface of the fine hemispherical layer 352, and the manufacturing process is complicated. Moreover, when the light is refracted and concentrated by the arc surface of the fine hemisphere 353, dispersion aberration will be formed at the focal point, resulting in an unsatisfactory light concentrating effect.

【Content of invention】

In order to overcome the problems of insufficient light uniformity and chromatic aberration in the prior art condensing sheet, the present invention provides a condensing sheet with high light uniformity and capable of eliminating chromatic aberration.

In order to overcome the problems of insufficient light uniformity and chromatic aberration in the prior art backlight module, the present invention provides a backlight module with high light uniformity and capable of eliminating chromatic aberration.

The technical solution adopted by the present invention to solve the technical problem is to provide a light-condensing sheet, the light-condensing sheet includes a light incident surface for receiving light, a light exit surface opposite to the light incident surface, and the light exit surface has a phenanthrene Nellie lens array.

The technical solution adopted by the present invention to solve the technical problem is to provide a backlight module, which includes a light source, a reflection sheet, a light guide plate, a diffusion sheet and a light concentrating sheet, wherein the light source is located on one side of the light guide plate , the reflective sheet, the light guide plate, the diffusion sheet and the light-condensing sheet are placed in sequence, the light-condensing sheet includes a light incident surface for receiving light, and a light exit surface opposite to the light incident surface, the light exit surface has a Fresnel lens array.

Compared with the prior art, since the light-emitting surface of the light-condensing sheet in the backlight module of the present invention has a Fresnel lens array, the single Fresnel lens can gather light at one point, and the several light-condensing points can form a single point. Uniform light-gathering surface, and the single Fresnel lens can eliminate dispersion and aberration, so as to obtain ideal display effect.

【Description of drawings】

FIG. 1 is a plan view of a prior art backlight module.

FIG. 2 is a perspective view of a light-condensing sheet disclosed in the prior art international patent application WO96/23649.

Fig. 3 is a view of the light concentrating sheet disclosed in the prior art Chinese Patent No. 01200551.

Fig. 4 is a schematic perspective view of a light concentrating sheet of the present invention.

Fig. 5 is a partially enlarged cross-sectional view of the light-condensing sheet of the present invention.

Fig. 6 is a plan view of the backlight module of the present invention.

【Detailed ways】

Please refer to FIG. 4 , which is a three-dimensional schematic view of the light-condensing sheet of the present invention. The condensing sheet 45 includes a light incident surface 454 for receiving light, and a light exit surface 455 opposite to the light incident surface 454, wherein the light exit surface 455 has a Fresnel lens array 452, and the Fresnel lens array 452 is composed of a plurality of Fresnel lenses 453 arranged. The Fresnel lenses 453 are convex points of the same size and configured as concentric multi-stage cylinders. 455 is the rough side.

Please refer to Fig. 5 together, the light enters the light-condensing sheet 45 through the light incident surface 454, and condenses light through the Fresnel lens array 452, and finally exits from the light-emitting surface 455 of the light-condensing sheet to form an array of focusing points, so that the light output Uniform, so as to improve the light-gathering effect, and the light-gathering efficiency can be controlled by the number of steps on the upper surface of the Fresnel lens.

Ordinary refracting convex lens has a small refraction angle for long-wavelength light, and gathers the focal point at a far position behind the lens; it has a large refraction angle for short-wavelength light, and gathers a focal point at a close position behind the lens, so axial chromatic aberration in the order of blue, green, and red is formed at the focal point . Contrary to the above-mentioned ordinary refracting convex lens, the single-layer diffractive lens has a large diffraction angle for long-wavelength light, and gathers the focal point near the back of the lens; it has a small diffraction angle for short-wavelength light, and gathers the focal point far behind the lens, so it is at the focal point Axial chromatic aberration in the order of red, green, and blue is formed. The Fresnel lens 453 on the light-emitting surface 455 of the light-condensing sheet of the present invention is a convex point of a concentric multi-stage cylindrical structure, and is a combination of a single-layer diffractive lens and an ordinary refracting convex lens. When the sheet 45 passes through the Fresnel lens array 452, the chromatic aberrations in opposite orders can cancel each other to correct the axial chromatic aberration, thereby improving the light-gathering effect.

The material of the condensing sheet 45 is an organic resin with high refractive index, good transparency and light transmittance, such as polyester (Polyester), polycarbonate (Polycarbonate, PC) and polymethyl methacrylate (Polymethyl Methacrylate, PMMA) etc.

The light concentrating sheet 45 can be directly manufactured on the equipment for manufacturing the light guide plate, by using electron beams or lasers to directly process the mold core for making the light concentrating sheet 45 or by electron beam lithography. A Fresnel lens array structure is formed on it, and is extruded together with the light-condensing sheet 45 through injection molding.

Please refer to FIG. 6, which is a schematic plan view of the backlight module of the present invention. The backlight module 5 includes a light source 51, a reflective sheet 52, a light guide plate 53, a diffusion sheet 54 and a light concentrating sheet 45, wherein the light source 51 is located on the light incident surface 534 side of the light guide plate, the reflector 52, the light guide plate 53, the diffuser 54 and the light concentrating film 45 are placed in sequence, and the light concentrating film 45 includes a light incident surface 454 for receiving light, a The light incident surface 454 is opposite to the light exit surface 455 , the light exit surface 455 has a Fresnel lens array 452 , and the Fresnel lens array 452 is composed of a plurality of Fresnel lenses 453 arranged in arrangement.

The light emitted by the light source 51 enters the light guide plate 53 through the light incident surface 534 of the light guide plate, a part of the light is directly emitted through the light exit surface 535 of the light guide plate, and part of the light is emitted through the light exit surface 535 of the light guide plate after multiple reflections by the reflector 52. After being diffused by the diffusion sheet 54, the outgoing light enters the light-condensing sheet 45 from the light-incident surface 454 of the light-condensing sheet, and is condensed by the Fresnel lens array 452, and finally exits from the light-emitting surface 455 of the light-condensing sheet to form an array of focusing points , so that the light is uniform, thereby improving the brightness of the lighting.

Claims (8)

1. concentration piece, it comprises incidence surface and the exiting surface that is oppositely arranged, and it is characterized in that: this concentration piece exiting surface has array of fresnel lenses.

2. concentration piece as claimed in claim 1 is characterized in that: this array of fresnel lenses is rearranged for concentric multistage cylindrical salient point by a plurality of big or small identical construction.

3. concentration piece as claimed in claim 1 is characterized in that: this array of fresnel lenses and concentration piece are structure as a whole.

4. concentration piece as claimed in claim 1 is characterized in that: the material of this concentration piece is polyester, polycarbonate or polymethylmethacrylate.

5. module backlight, it comprises a light source, a reflector plate, a light guide plate, a diffusion sheet and a concentration piece, wherein, this light source is positioned at light guide plate one side, this reflector plate, light guide plate, diffusion sheet and concentration piece are placed successively, this concentration piece comprises incidence surface and the exiting surface that is oppositely arranged, and it is characterized in that: this concentration piece exiting surface has array of fresnel lenses.

6. module backlight as claimed in claim 5 is characterized in that: this array of fresnel lenses is rearranged for concentric multistage cylindrical salient point by a plurality of big or small identical construction.

7. module backlight as claimed in claim 5 is characterized in that: this array of fresnel lenses and this concentration piece are integrative-structures.

8. module backlight as claimed in claim 5 is characterized in that: the material of this concentration piece is polyester, polycarbonate or polymethylmethacrylate.

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