Backlighting module and light guide module both comprising gradient index lens

Patent metadata

Field	Value
Publication number	US-2016124134-A1
Application number	US-201514666062-A
Country	US
Kind code	A1
Filing date	Mar 23, 2015
Priority date	Oct 30, 2014
Publication date	May 5, 2016
Grant date	—

Abstract

A light guide module includes a light guide plate and a gradient index lens. The light guide plate has a light output surface and a light incident surface. The light incident surface is connected to the light output surface. The gradient index lens has a first surface, a second surface and a third surface. The first surface and the second surface are connected to the third surface. The first surface of the gradient index lens is attached to the light output surface. Multiple internal refractive indexes of the gradient index lens are increased gradually from the first surface to the second surface. A minimum refractive index of the multiple internal refractive indexes is less than a refractive index of the light guide plate. The incident light is refracted multiple times within the gradient index lens, and totally reflected back to the light guide plate.

First claim

What is claimed is:

1 . A light guide module, configured to be adjacent to a light source capable of emitting an incident light, comprising:
a light guide plate having a light output surface and an light incident surface, the light incident surface being connected to an end of the light output surface, and the light incident surface being adjacent to and facing toward the light source for receiving the incident light; and a gradient index lens having a first surface, a second surface and a third surface with two ends which are opposite to each other, the first surface being parallel to and opposite to the second surface, the first surface and the second surface being connected to the two ends of the third surface, respectively, the first surface of the gradient index lens being attached to the light output surface of the light guide plate, and both the third surface of the gradient index lens and the light incident surface of the light guide plate facing toward the light source for receiving the incident light; wherein a plurality of internal refractive indexes of the gradient index lens is increased gradually from the first surface to the second surface, a minimum refractive index of the plurality of internal refractive indexes is less than a refractive index of the light guide plate, such that after the incident light enters the gradient index lens, the incident light is refracted a plurality of times within the gradient index lens, and totally reflected back to the light guide plate by the second surface of the gradient index lens.

2 . The light guide module according to claim 1 , wherein the gradient index lens comprises a plurality of light-transmissive layers, the quantity of the plurality of light-transmissive layers is i, i≧2, the plurality of light-transmissive layers is stacked up sequentially from the first light-transmissive layer to the i-th light-transmissive layer, the plurality of light-transmissive layers has a plurality of refractive indexes respectively, each refractive index is different from one another, and the plurality of refractive indexes satisfies the following condition:
1< n 1< n 2< . . . < ni;

wherein ni is a refractive index of the i-th light-transmissive layer.

3 . The light guide module according to claim 2 , wherein the light guide module satisfies the following condition:
1.2< ni< 1.6.

4 . The light guide module according to claim 2 , wherein the refractive index of the light guide plate is ng, and the light guide module satisfies the following condition:
n 1< ng.

5 . The light guide module according to claim 2 , wherein each light-transmissive layer is made from at least one material, and when the quantity of the at least one material is more than one, the materials are stacked on one another.

6 . The light guide module according to claim 5 , wherein a thickness of one of the plurality of light-transmissive layers is d, a wavelength of the incident light is λ, and when the quantity of the at least one material of each light-transmissive layer is more than one and the materials are stacked on one another, the light guide module satisfies the following condition:
d< 0.25λ.

7 . The light guide module according to claim 2 , wherein each thickness of each light-transmissive layer is different from one another.

8 . The light guide module according to claim 7 , wherein the plurality of thicknesses of the plurality of light-transmissive layers is increased or decreased gradually from the first surface to the second surface of the gradient index lens.

9 . The light guide module according to claim 2 , wherein a difference between every two refractive indexes of every two of the plurality of light-transmissive layer which are neighboring to each other is a constant.

10 . The light guide module according to claim 1 , wherein the gradient index lens is manufactured by attachment or co-extrusion.

11 . The light guide module according to claim 1 , wherein the gradient index lens is manufactured by ion implantation, and an ion concentration of the gradient index lens is increased or decreased gradually from the first surface to the second surface of the gradient index lens.

12 . The light guide module according to claim 1 , wherein a vertical direction is defined to be parallel to a normal direction of the light output surface of the light guide plate, a horizontal direction is defined to be parallel to a normal direction of the light incident surface of the light guide plate, the gradient index lens has a thickness H along the vertical direction, the gradient index lens has a width W along the horizontal direction, and satisfy the following condition:
W≧ 10 H.

13 . The light guide module according to claim 1 , wherein the gradient index lens is made of glass or transparent plastic, and the transparent plastic is polycarbonate, polymethyl methacrylate, methyl methacrylate-styrene copolymers, polystyrene, polyethylene terephthalate, cyclic olefin copolymer, cyclo olefin polymer, polyethylene naphthalate or polylactide.

14 . The light guide module according to claim 1 , wherein the third surface of the gradient index lens and the light incident surface of the light guide plate are co-planar.

15 . A backlighting module, comprising:
a light guide module comprising a gradient index lens according to claim 1 ; and a light source having a light emitting surface, the light emitting surface facing toward the light incident surface of the light guide plate and the third surface of the gradient index lens.

16 . The backlighting module according to claim 15 , wherein the gradient index lens comprises a plurality of light-transmissive layers, the quantity of the plurality of light-transmissive layers is i, i≧2, the plurality of light-transmissive layers is stacked up sequentially from the first light-transmissive layer to the i-th light-transmissive layer, the plurality of light-transmissive layers has a plurality of refractive indexes respectively, each refractive index is different from one another, and the plurality of refractive indexes satisfies the following condition:
1< n 1< n 2< . . . < ni;

wherein ni is a refractive index of the i-th light-transmissive layer.

17 . The backlighting module according to claim 16 , wherein each light-transmissive layer is made from at least one material, and when the quantity of the at least one material is more than one, the materials are stacked on one another.

18 . The backlighting module according to claim 16 , wherein each thickness of each light-transmissive layer is different from one another.

19 . The backlighting module according to claim 18 , wherein the plurality of thicknesses of the plurality of light-transmissive layers is increased or decreased gradually from the first surface to the second surface of the gradient index lens.

20 . The backlighting module according to claim 16 , wherein a difference between every two refractive indexes of every two of the plurality of light-transmissive layer which are neighboring to each other is a constant.

Assignees

• Wistron Corp

Inventors

• Zhu yan-fei
• Chen Chih-Yen

Classifications

• G02B6/005 Primary

  provided by one optical element, or plurality thereof, placed on the light output side of the light guide · CPC title

• G02B6/0088

  of the light guide or other optical sheets in the package · CPC title

• G02B6/003 Primary

  Lens or lenticular sheet or layer · CPC title

• G02B6/0031

  Reflecting element, sheet or layer · CPC title