Liquid crystal display and backlight module thereof

Abstract

A backlight module includes a reflection sheet and a film structure disposed above the reflection sheet with a gap therebetween. A light source is disposed in the gap between the reflection sheet and the film structure so as to provide light. The film structure includes a first region for reflecting light incident thereupon from the light source and the reflection sheet, and a plurality of second regions for transmitting at least partially light incident thereupon from the light source and the reflection sheet.

1 . A backlight module, comprising:
 a reflection sheet;   a first reflective type polarizer disposed above the reflection sheet with a gap therebetween;   a light source disposed in said gap between the reflection sheet and the first reflective type polarizer to provide light;   a retarder disposed on the first reflective type polarizer, the retarder having a plurality of retarding regions and a non-retarding region; and   a second reflective type polarizer disposed on the retarder, wherein the light provided by the light source penetrating the second reflective type polarizer through the functioning of the retarding regions.   
     
     
         2 . The backlight module of  claim 1 , wherein the first reflective type polarizer and the second reflective type polarizer are linear polarizers, and a linear polarization direction of the first reflective type polarizer and a linear polarization direction of a light passing the second reflective type polarizer are perpendicular to each other. 
     
     
         3 . The backlight module of  claim 1 , wherein the first reflective type polarizer and the second reflective type polarizer are circular polarizers, and a circular polarization direction of the first reflective type polarizer and a circular polarization direction of the second reflective type polarizer are opposite to each other. 
     
     
         4 . The backlight module of  claim 3 , further comprising a ¼ wavelength retarder disposed on the second reflective type polarizer. 
     
     
         5 . The backlight module of  claim 1 , being a side incident type backlight module wherein the light source is located along an edge of the reflection sheet and emits light towards a central region of the reflection sheet. 
     
     
         6 . The backlight module of  claim 5 , further comprising a lens disposed on a light-emitting path of the light source. 
     
     
         7 . The backlight module of  claim 1 , being a direct type backlight module wherein the light source comprises a plurality of light-emitting elements evenly distributed on the reflection sheet. 
     
     
         8 . The backlight module of  claim 1 , further comprising a plurality of fasteners for fixing relative positions of the reflection sheet, the first reflective type polarizer, the retarder and the second reflective polarizer. 
     
     
         9 . The backlight module of  claim 8 , wherein the reflection sheet, the first reflective type polarizer, the retarder and the second reflective type polarizer have a plurality of through holes respectively, the fasteners running through the through holes to fasten the reflection sheet, the first reflective type polarizer, the retarder and the second reflective type polarizer, a largest dimension of at least one of the through holes being larger than a largest external diameter of the respective fasteners. 
     
     
         10 . The backlight module of  claim 9 , wherein the reflection sheet, the first reflective type polarizer, the retarder and the second reflective type polarizer are flexible. 
     
     
         11 . The backlight module of  claim 1 , further comprising a support disposed between the reflection sheet and the first reflective type polarizer to maintain the gap. 
     
     
         12 . The backlight module of  claim 11 , further comprising a transparent support plate disposed between the first reflective type polarizer and the support. 
     
     
         13 . The backlight module of  claim 1 , wherein the retarder is a ½ wavelength retarder. 
     
     
         14 . The backlight module of  claim 1 , wherein a total area of the retarding regions per unit area of the retarder increases as the retarding regions are farther away from the light source. 
     
     
         15 . A backlight module, comprising:
 a reflection sheet;   a selective reflection sheet disposed above the reflection sheet with a gap therebetween, the selective reflection sheet having a plurality of transparent regions and a reflective region; and   a light source disposed in the gap between the reflection sheet and the selective reflection sheet so as to provide light.   
     
     
         16 . The backlight module of  claim 15 , wherein a total area of the transparent regions per unit area of the selective reflection sheet increases as the transparent regions are farther away from the light source. 
     
     
         17 . A liquid crystal display (LCD), comprising:
 an LCD panel; and   a backlight module as defined in  claim 1 .   
     
     
         18 . The LCD of  claim 17 , further comprising:
 a first polarizer disposed between the backlight module and the LCD panel; and   a second polarizer disposed on the LCD panel,   wherein linear polarization directions of the first polarizer and the second polarizer are perpendicular to each other.   
     
     
         19 . An LCD, comprising:
 an LCD panel; and   a backlight module as defined in  claim 15 .   
     
     
         20 . The LCD of  claim 19 , further comprising:
 a first polarizer disposed between the backlight module and the LCD panel; and   a second polarizer disposed on the LCD panel,   wherein linear polarization directions of the first polarizer and the second polarizer are perpendicular to each other.   
     
     
         21 . A backlight module, comprising:
 a reflection sheet;   a film structure disposed above the reflection sheet with a gap therebetween; and   a light source disposed in the gap between the reflection sheet and the film structure so as to provide light;   wherein the film structure comprises   a first region for reflecting light incident thereupon from the light source and the reflection sheet; and   a plurality of second regions for transmitting at least partially light incident thereupon from the light source and the reflection sheet.   
     
     
         22 . The backlight module of  claim 21 , wherein a total area of the second regions per unit area of the film structure increases as the second regions are farther away from the light source. 
     
     
         23 . The backlight module of  claim 22 , being a side incident type backlight module wherein
 the light source is located along an edge of the reflection sheet and emits light towards a central region of the reflection sheet; and   the second regions are distributed on the film structure such that a surface source with uniform luminance is provided at a top side of the film structure.   
     
     
         24 . An LCD, comprising an LCD panel and a backlight module as defined in  claim 21 .