CN1782802A - Light guide plate and back light module - Google Patents

Abstract

The present invention relates to a kind of light guide plate and one back light module. The light guide plate has one bottom surface, at least one light incoming surface and several light guide units. The light guide units are stacked and arranged in the direction apart from the light incoming surface. Two adjacent light guide units have different refractive indexes, and the interface between two adjacent light guide units is inclined to the light incoming surface. The light guide plate makes the back light module possess raised light utilization rate.

Description

Light guide plate and module backlight

[technical field]

The invention relates to a kind of light guide plate and module backlight, particularly about a kind of light guide plate and module backlight that promotes the efficiency of light energy utilization.

[background technology]

In recent years, along with the colorize and the maximization of LCD, its application is more extensive, as notebook computer, various desk-top computer and LCD TV etc.Because the liquid crystal display module is a kind of non-self-emission display apparatus, it shows mainly passing through or the obstructed realization of coming by control light beam that external light source sends, therefore need corresponding backlight or preceding optical mode group usually, this backlight or preceding optical mode group can realize Presentation Function with the beam direction display panel that external light source sent.

Seeing also Fig. 1, is a kind of prior art module 10 backlight, mainly is made up of light source 11, light guide plate 12, diffuser plate 13, prism plate combination 14 and reflecting plate 16.This light guide plate 12 comprises a plane of incidence 121, an exit facet 122 and a bottom surface 123, wherein, this plane of incidence 121 receives the light beam that the light source 11 relative with it sends, and with these light beam importing light guide plate 12 inside, this bottom surface 123 should import beam reflection, scattering, formation is along the homodisperse scattered beam of all directions, and this exit facet 122 should be derived light guide plate 12 by homodisperse light beam, guiding display panels (figure does not show).The scattering of these 123 pairs of light beams in bottom surface is to realize that by site 124 this site 124 can utilize mode of printing, with the high reflectance not material such as the titania (TiO of extinction ₂) be printed on this bottom surface 123 with the form of circular or square diffusion point.This site 124 can change the direct of travel of these light guide plate 12 internal communication light, destroy its total reflection condition, and, light is evenly penetrated by the exiting surface 122 of this light guide plate 12 by controlling the distribution of this site 124, realize the display panels even illumination of (figure does not show).

See also Fig. 2, it is the light guide plate 22 of another kind of prior art, has groove 224 on the bottom surface 223 of this light guide plate 22, this groove 224 can be made by ejection formation or hot-forming and other method, it destroys the total reflection condition of these light guide plate 22 internal communication light beams by reflection, refraction, and, light is evenly penetrated by the exiting surface 222 of this light guide plate 22 by controlling shape, height or its spacing distance of this groove 224.

The light guide plate of above-mentioned two kinds of prior aries is only carried out scattering to the light that incides the bottom surface, the light that is parallel to the bottom surface then penetrates by material absorption itself or by other surface, and the light that is scattered transmits to different directions, the light that only is dispersed into directly over the light guide plate is penetrated by the exiting surface of light guide plate, and other light is absorbed by material itself or by penetrating on other surface, thereby the efficiency of light energy utilization of light guide plate is lower.

[summary of the invention]

For solving the lower problem of the efficiency of light energy utilization of light guide plate in the prior art module backlight, the invention provides a kind of light guide plate with higher efficiency of light energy utilization.

For solving the lower problem of the efficiency of light energy utilization of prior art module backlight, the present invention also provides a kind of module backlight with higher efficiency of light energy utilization.

The technical scheme that technical solution problem of the present invention is adopted is: a kind of light guide plate is provided, it has a bottom surface and at least one incidence surface, this light guide plate comprises a plurality of light elements, these a plurality of light elements are arranged along the direction away from this light guide plate incidence surface, adjacent two light elements have different refractive index arbitrarily, and the interphase between this light element and this incidence surface tilt.

The incidence surface of light guide plate of the present invention further is provided with optical grating construction.

The exiting surface of light guide plate of the present invention further is provided with stripe shape or pyramid projection.

The present invention also provides a kind of module backlight, it comprises a light guide plate, a reflecting plate and at least one light source, this light guide plate comprises an exiting surface, one with this exiting surface opposed bottom surface and at least one incidence surface that links to each other with this exiting surface, this reflecting plate this bottom surface relatively is provided with, this light source this incidence surface relatively is provided with, this light guide plate comprises a plurality of light elements, these a plurality of light elements are along the direction phase stacked arrangement away from this light guide plate incidence surface, adjacent two light elements have different refractive index, and the interphase between this light element and this incidence surface tilt.

Module backlight of the present invention further is provided with a polarization separation element at the exiting surface of light guide plate, between the bottom surface of light guide plate and reflecting plate a polarization element is set.

Compared with prior art, light guide plate of the present invention is formed by a plurality of light element stacked arrangement, interfacial angle of inclination between the refringence between adjacent two light elements of utilization change and this two light element, reflection and the refraction of control light on this interphase, these all light of light guide plate internal transmission are evenly penetrated by the exiting surface of this light guide plate, thereby overcome the optical energy loss that scattering phenomenon caused of prior art.The optical grating construction of the incidence surface setting of light guide plate of the present invention can further be lifted into optical efficiency by diffraction effect.The exiting surface raised structures of light guide plate of the present invention can converge emergent ray, improves the bright dipping briliancy perpendicular to this light guide plate exiting surface direction.Polarization separation element that module backlight of the present invention is included and polarization element can be converted into the part polarized light that is originally absorbed by the polaroid of liquid crystal panel (figure does not show) can be by the polarized light of polaroid, thereby promotes the efficiency of light energy utilization of module backlight.

[description of drawings]

Fig. 1 is the structural representation of a kind of prior art module backlight.

Fig. 2 is the structural representation of another kind of prior art light guide plate.

Fig. 3 is the work synoptic diagram of light guide plate first embodiment of the present invention.

Fig. 4 is the structural representation of the incidence surface of light guide plate first embodiment of the present invention.

Fig. 5 is the structural representation of the incidence surface of light guide plate second embodiment of the present invention.

Fig. 6 is the structural representation of the exiting surface of light guide plate the 3rd embodiment of the present invention.

Fig. 7 is the structural representation of the present invention's module first embodiment backlight.

Fig. 8 is the structural representation of the present invention's module second embodiment backlight.

[embodiment]

Seeing also Fig. 3, is the structural representation of light guide plate first embodiment of the present invention.This light guide plate 32 has an incidence surface 321 and a bottom surface 323, these light guide plate 32 inside comprise a plurality of light elements 320, the material of this light element 320 can be two kinds in methacrylic resin, polyacrylic resin, polycarbonate, the polyvinyl resin, also can select two or more materials, perhaps the different blended condensation material of above-mentioned material.These a plurality of light elements 320 are arranged along the direction away from these light guide plate 32 incidence surfaces 321, two adjacent light elements have different refractive index, interphase 324 and this incidence surface 321 of this light element 320 tilt, light by incidence surface 321 incidents of this light guide plate 32 produces refraction and reflection through this interphase 324, and interfacial transmissivity Ti of its i layer and reflectivity Ri can be expressed as:

R _i＝|γ _p,i| ²+|γ _s,i| ²；T _i＝|t _p,i| ²+|t _s，i| ²

Wherein:

${\mathrm{\γ}}_{p,1}=-\frac{n_{i+1}\cos {\mathrm{\θ}}_i-n_i\cos {\mathrm{\θ}}_{i+1}}{n_{i+1}\cos {\mathrm{\θ}}_i+n_i\cos {\mathrm{\θ}}_{i+1}};$

${\mathrm{\γ}}_{s,1}=-\frac{n_{i+1}\cos {\mathrm{\θ}}_{i+1}-n_i\cos {\mathrm{\θ}}_i}{n_{i+1}\cos {\mathrm{\θ}}_{i+1}+n_i\cos {\mathrm{\θ}}_i};$

$t_{p,1}=-\frac{{2n}_i\cos {\mathrm{\θ}}_i}{n_{i+1}\cos {\mathrm{\θ}}_i+n_i\cos {\mathrm{\θ}}_{i+1}};$

$t_{s,1}=-\frac{{2n}_i\cos {\mathrm{\θ}}_i}{n_{i+1}\cos {\mathrm{\θ}}_{i+1}+n_i\cos {\mathrm{\θ}}_i};$

γ _Si, γ _{P, i}Represent that respectively S polarized light and P polarized light are in the reflection coefficient of i layer interphase 324, t _{S, i}, t _{P, i}Represent that respectively S polarized light and P polarized light are in the transmission coefficient of i layer interphase 324.The present invention can make the exiting surface 322 even outgoing of the light of these light guide plate 30 inside by this light guide plate 30 by the refractive index of each light element 320 of adjustment and the angle of each interphase 324.

See also Fig. 4, the incidence surface of light guide plate 42 of the present invention can further be set to optical grating construction 44, makes light effectively enter this light guide plate 42, and the direct of travel of may command light.

See also Fig. 5, the incidence surface of light guide plate 52 of the present invention can further be set to arcuate surface 56, and light is further concentrated.

See also Fig. 6, the exiting surface 622 of light guide plate 62 of the present invention can further be set to raised structures 624, and emergent ray is converged to the vertical direction of this exiting surface 622, and this raised structures 624 can be stripe shape projection or pyramid projection.

Seeing also Fig. 7, is the structural representation of first embodiment of the present invention's module 70 backlight.This module 70 backlight comprises light source 71, light guide plate 72, diffuser plate 73, prism plate 74 and reflecting plate 76.This light guide plate 72 comprises an incidence surface 721 and a bottom surface 723, these these light guide plate 72 inside comprise a plurality of light elements 720, the material of this light element 720 can be two kinds in methacrylic resin, polyacrylic resin, polycarbonate, the polyvinyl resin, also can select two or more materials, perhaps the different blended condensation material of above-mentioned material.These a plurality of light elements 720 are arranged along incidence surface 721 directions away from this light guide plate 72, adjacent two light elements have different refractive index, the interphase 724 of this light element 720, this interphase 724 is planes, tilt with this incidence surface 721, produce refraction and reflection through this interphase 724 by the light of incidence surface 721 incidents of this light guide plate 72.The refractive index by adjusting each light element 720 and the angle of each interphase 724 can make the exiting surface 722 even outgoing of these light guide plate 72 internal light by this light guide plate 72.

Seeing also Fig. 8, is the structural representation of the present invention's module second embodiment backlight.This module 80 backlight is except that comprising light source 81, light guide plate 82, reflecting plate 86, it further is provided with a polarization separation element 88 at the exiting surface 822 of this light guide plate 82, between the bottom surface 823 of this light guide plate 82 and this reflecting plate 86, a polarization element 87 is set, this polarization separation element 82 can be multilayer membrane type reflecting polarizer (the DualBrightness Enhance Film that 3M company (Minnesota Mining andManufacturing Company) produces, DBEF), this polarization element 87 is quarter-wave plates.Interphase 824 refractions and reflection that are had the light-guide device 820 of different refractivity by the light of incidence surface 821 incidents of this light guide plate 82, via exiting surface 822 outgoing, this emergent ray is a natural light, it incides this polarization separation element 88, this polarization separation element 88 makes the wherein polarized light transmission of a polarization direction, and the vertically polarized light of this polarization direction reflection, this reflection ray enters this light guide plate 82, and be converted into through the bit phase delay of this polarization element 87 and 86 reflections of this reflecting plate can be by the light of these polarization separation element 88 transmissions, this module 80 backlight can make the part polarized light that is absorbed by the polaroid of liquid crystal panel (figure does not show) originally be converted into can pass through the polarized light of this polaroid, and then promotes the light extraction efficiency of module backlight.This polarization separation element 88 can also adopt the realization that matches with quarter-wave plate of cholesterol formula reflecting polarizer.

Claims (14)

1. light guide plate, it has a bottom surface and at least one incidence surface, it is characterized in that: this light guide plate inside further comprises a plurality of light elements, these a plurality of light elements are arranged along the direction away from this light guide plate incidence surface, two adjacent light elements have different refractive index arbitrarily, and the interphase between this light element and this incidence surface tilt.

2. light guide plate as claimed in claim 1 is characterized in that: these a plurality of light elements are at least two kinds of resin materials that refractive index is different.

3. light guide plate as claimed in claim 2 is characterized in that: these a plurality of light elements are at least two kinds or its made from mixed materials in methacrylic resin, polyacrylic resin, polycarbonate, the polyvinyl resin.

4. light guide plate as claimed in claim 1 is characterized in that: this interphase is a plane.

5. light guide plate as claimed in claim 1 is characterized in that: the incidence surface of this light guide plate has optical grating construction.

6. light guide plate as claimed in claim 1 is characterized in that: the incidence surface of this light guide plate is the arc structure to the inboard depression of this light guide plate.

7. light guide plate as claimed in claim 1 is characterized in that: the exiting surface of this light guide plate has raised structures.

8. light guide plate as claimed in claim 7 is characterized in that: this raised structures is stripe shape projection or the pyramid raised structures that is parallel to this incidence surface.

9. module backlight, it comprises:

One light guide plate, it comprises an exiting surface, one with this exiting surface opposed bottom surface and at least one incidence surface that links to each other with this exiting surface;

One reflecting plate, it is provided with this bottom surface relatively;

At least one light source, it is this incidence surface setting relatively;

It is characterized in that: this light guide plate inside further comprises a plurality of light elements, these a plurality of light elements are along the incidence surface direction phase stacked arrangement away from this light guide plate, adjacent two light elements have different refractive index, and the interphase between this light element and this incidence surface tilt.

10. module backlight as claimed in claim 9 is characterized in that: these a plurality of light elements are at least two kinds of resin materials that refractive index is different.

11. module backlight as claimed in claim 10 is characterized in that: the material of these a plurality of light elements is at least two kinds or its made from mixed materials in methacrylic resin, polyacrylic resin, polycarbonate, the polyvinyl resin.

12. module backlight as claimed in claim 9, it is characterized in that: this module backlight further comprises a polarization separation element and a polarization element, this reflection of polarization element is provided with the exiting surface with this light guide plate, between the bottom surface and this reflecting plate of this polarization element setting and this light guide plate.

13. module backlight as claimed in claim 12 is characterized in that: this polarization separation element is a multilayer membrane type reflecting polarizer or a cholesterol formula reflecting polarizer.

14. module backlight as claimed in claim 12 is characterized in that: this polarization element is a quarter-wave plate.

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