Patent Publication Number: US-2009231859-A1

Title: Brightness Enhancement Component

Description:
RELATED APPLICATIONS 
     This application claims priority to Taiwan Application Serial Numbers 97204232 and 97204233, both filed Mar. 12, 2008, which are herein incorporated by reference. 
     BACKGROUND 
     1. Field of Invention 
     The present invention relates generally to a brightness enhancement film, and more particularly, relates to the brightness used in a backlit liquid crystal display. 
     2. Description of Related Art 
     A backlit liquid crystal display generally includes a brightness enhancement film which is typically positioned between a diffuser and a liquid crystal display panel. The backlit liquid crystal display also includes a light source such as a fluorescent lamp, a light guide for transporting light for reflection toward the liquid crystal display panel, and white reflector for reflecting light toward the liquid crystal display panel. The brightness enhancement film collimates light emitted from the light guide thereby increasing the brightness of the liquid crystal display panel. The increased brightness enables a sharper image to be produced by the liquid crystal display panel and allows the power of the light source to be reduced to produce a selected brightness. The brightness enhancement film in the backlit liquid crystal display is useful in equipment such as computers, personal TVs, video recorders, mobile communication devices, and automobile and avionics instrument displays. 
     SUMMARY 
     It is therefore an objective of the present invention to provide a brightness enhancement component. 
     In accordance with the foregoing and other objectives of the present invention, a brightness enhancement component comprises a substrate and a plurality of prism elements. The prism elements are disposed on the substrate, and each element prism has a relatively high crest and at least one relatively low crest. A crest line of the relatively low crest is shorter than a crest line of the relatively high crest, wherein all of the relatively high crests have their crest lines in parallel with one another. 
     In accordance with the foregoing and other objectives of the present invention, a brightness enhancement component comprises a substrate and a plurality of prism elements. The prism elements are disposed on the substrate, and each element prism has a relatively high crest and at least one relatively low crest. A crest line of the relatively low crest is equal to a crest line of the relatively high crest in length, wherein all of the relatively high crests and relatively low crests have their crest lines in parallel with one another. 
     The brightness enhancement components discussed in preferred embodiments can be used in an illumination device, i.e. a lamp, and flat panel displays, i.e. a liquid crystal display, to improve its brightness performance. In addition, the improved design on the prism element, i.e. the relative high and relative low crest, can effectively reduce Moiré effects or patterns. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, 
         FIG. 1  illustrates a brightness enhancement component according to one preferred embodiment of this invention; 
         FIG. 2  illustrates a cross-sectional view of the brightness enhancement component as illustrated in  FIG. 1 ; 
         FIGS. 3 and 4  respectively illustrate enlarged cross-sectional views of a prism element as illustrated in  FIG. 2 ; 
         FIG. 5  illustrates a brightness enhancement component according to another preferred embodiment of this invention; 
         FIG. 6  illustrates a cross-sectional view of the brightness enhancement component as illustrated in  FIG. 5 ; and 
         FIGS. 7 and 8  respectively illustrate enlarged cross-sectional views of a prism element as illustrated in  FIG. 6 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     Referring to  FIGS. 1 and 2 , a brightness enhancement component  100  and its cross-sectional view are illustrated. The brightness enhancement component  100  includes a substrate  102  and a plurality of prism elements  104  arranged on the substrate  102 . Each prism element  104  basically consists of two opposite facets, i.e. facets  104   a ,  104   b  as illustrated in  FIG. 3 , which intersect at the relatively high crest  106 . Each prism element  104  also includes a relatively high crest  106  and at least one relatively low crest  108 . All crest lines ( 106   a ,  108   a ) of the relatively high crests  106  and relatively low crests  108  are in parallel with one another. In each prism element, a crest line of the relatively high crest is equal to a crest line of the relatively low crest in length. In one preferred embodiment, all the relatively low crests  108  are at either one of two opposite facets. In another preferred embodiment, the relatively low crests  108  are arranged at both of two opposite facets (not illustrated in drawings). In another preferred embodiment, an interval W 1  between immediately-adjacent two of the relatively low crests  108  at one of the two opposing facets measures between 2 microns and 15 microns. In still another preferred embodiment, a V-shaped (in cross-sectional view) prism trough  110  is formed between immediately-adjacent two prism elements  104 . 
     Referring to  FIGS. 3 and 4 , an enlarged cross-sectional view of single prism element is illustrated. 
     In  FIGS. 3 and 4 , several critical dimensions as to brightness enhancement are illustrated. In one preferred embodiment, the relatively high crest  106  has a height H 1  ranging from 10 microns to 100 microns above the substrate  102  (as illustrated in  FIG. 2 ). In another preferred embodiment, the relatively high crest  106  has a height H 1  ranging from 10 microns to 50 microns above the substrate  102 . 
     In one preferred embodiment, a ratio of H 2  to H 1  is less than 0.20. In another preferred embodiment, a ratio of H 2  to H 1  ranges from 0.01 to 0.10. Note that H 2  is a height of the relatively low crest  108  above a bottom of a V-shaped prism trough  107 , which is formed between the relatively high crest  106  and the relatively low crest  108 . 
     In one preferred embodiment, the relatively low crest  108  has a height H 2  ranging from 0.1 micron to 5.0 microns. In another preferred embodiment, the relatively low crest  108  has a height H 2  ranging from 1.0 micron to 2.0 microns. 
     In one preferred embodiment, the relatively low crest  108  is disposed higher than 66 percent of H 1  (a height of the relatively high crest  106 ) above the substrate in height. In another preferred embodiment, the relatively low crest  108  is disposed between 66 and 80 percent of H 1  (a height of the relatively high crest  106 ) above the substrate in height. 
     In one preferred embodiment, an included angle A 2  of the relatively low crest  108  measures between 70 degrees and 110 degrees. In another preferred embodiment, an included angle A 1  of the relatively high crest  106  measures between 70 degrees and 110 degrees. 
     Referring to  FIGS. 5 and 6 , a brightness enhancement component  200  and its cross-sectional view are illustrated. The brightness enhancement component  200  includes a substrate  202  and a plurality of prism elements  204  arranged on the substrate  202 . Each prism element  204  includes a relatively high crest  206  and at least one relatively low crest  208 , and basically consists of two opposite facets, i.e. facets  204   a ,  204   b  as illustrated in  FIG. 7 , which intersect at the relatively high crest  206 . All crest lines  206   a  of the relatively high crests  206  are in parallel with one another. A crest line  208   a  of the relatively low crest  208  is not a continuous crest line. That is, a crest line of the relatively low crest is shorter than a crest line of the relatively high crest in length in each prism element. 
     In one preferred embodiment, all crest lines ( 206   a  and  208   a ) of the relatively high crests  206  and the relatively low crests  208  are in parallel with one another. In another preferred embodiment, crest lines  208   a  of the relatively low crests  208  are not in parallel with crest lines  206   a  of the relatively high crests  206 , or part crest lines  208   a  of the relatively low crests  208  are not is in parallel with crest lines  206   a  of the relatively high crests  206 . 
     In one preferred embodiment, the relatively low crests  208  are all at either one of two opposite facets. In another preferred embodiment, the relatively low crests  208  are arranged at both of two opposite facets (not illustrated in drawings). In another preferred embodiment, an interval W 2  between immediately-adjacent two of the relatively low crests  208  at one of the two opposing facets measures between 2 microns and 15 microns. In still another preferred embodiment, a V-shaped (in cross-sectional view) prism trough  210  is formed between immediately-adjacent two prism elements  204 . 
     Referring to  FIGS. 7 and 8 , an enlarged cross-sectional view of single prism element is illustrated. 
     In  FIGS. 7 and 8 , several critical dimensions as to brightness enhancement are illustrated. In one preferred embodiment, the relatively high crest  206  has a height H 1  ranging from 10 microns to 100 microns above the substrate  202 . In another preferred embodiment, the relatively high crest  206  has a height H 1  ranging from 10 microns to 50 microns above the substrate  202 . 
     In one preferred embodiment, a ratio of H 2  to H 1  is less than 0.20. In another preferred embodiment, a ratio of H 2  to H 1  ranges from 0.01 to 0.10. Note that H 2  is a height of the relatively low crest  208  above a bottom of V-shaped prism trough  207 , which is formed between the relatively high crest  206  and the relatively low crest  208 . 
     In one preferred embodiment, the relatively low crest  208  has a height H 2  ranging from 0.1 micron to 5.0 microns. In another preferred embodiment, the relatively low crest  208  has a height H 2  ranging from 1.0 micron to 2.0 microns. 
     In one preferred embodiment, the relatively low crest  208  is disposed higher than 66 percent of H 1  (a height of the relatively high crest  206 ) above the substrate in height. In another preferred embodiment, the relatively low crest  208  is disposed between 66 and 80 percent of H 1  (a height of the relatively high crest  206 ) above the substrate in height. 
     In one preferred embodiment, an included angle A 2  of the relatively low crest  208  measures between 70 degrees and 110 degrees. In another preferred embodiment, an included angle A 1  of the relatively high crest  206  measures between 70 degrees and 110 degrees. 
     The brightness enhancement components discussed in preferred embodiments can be used in an illumination device, i.e. a lamp, and flat panel displays, i.e. a liquid crystal display, to improve its brightness performance. In addition, the improved design on the prism element, i.e. the relative high crest and relative low crest, can effectively reduce Moiré effects or patterns when the brightness enhancement components are applied within a backlight module. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.