Backlight module with light uniform design

Patent metadata

Field	Value
Publication number	US-9904105-B2
Application number	US-201514788130-A
Country	US
Kind code	B2
Filing date	Jun 30, 2015
Priority date	Sep 11, 2014
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A backlight module including a carrier plate, a plurality of light sources, at least one low reflective portion, and a modulation film is provided. The carrier plate has a carrier surface carrying the light sources while the low reflective portion is disposed on the carrier surface between an outer light source and a side edge of the carrier plate. The reflectance of the low reflective portion is less than that of the carrier surface. The modulation film is disposed above the light sources while the low reflective portion has a projection area on the modulation film. The projection area has a lower normalized transmission ratio comparing to adjacent areas along an extending direction of the side edge of the carrier plate.

First claim

What is claimed is:

1. A backlight module, comprising:
a carrier plate having a carrier surface, the carrier surface having a first reflectance;
a plurality of light sources disposed on the carrier plate and surrounded by part of the carrier surface, the light sources including a plurality of outer light sources distributed along a side edge of the carrier surface;
a plurality of low reflective portions formed on the carrier surface, the plurality of low reflective portions respectively correspondingly disposed between the outer light sources and the side edge of the carrier plate, wherein the low reflective portions have a second reflectance less than the first reflectance; and
a modulation film disposed above the light sources and having a plurality of light emitting structures, the modulation film distributing light generated by the light sources to emit the light through the light emitting structures at different positions,
wherein each of the low reflective portions has a projection area on the modulation film, and in a direction parallel to an extending direction of the side edge of the carrier plate, the projection area has a lower normalized transmission ratio compared to adjacent areas; and
wherein the carrier surface comprises:
a bottom area having an end edge, wherein the outer light sources are disposed on the bottom area and adjacent to the end edge; and
an inclined area inclined from the end edge and extending outwardly toward the modulation film, wherein the inclined area is distributed along the side edge;
wherein at least part of the low reflective portion is formed on the inclined area.

2. The backlight module of claim 1 , wherein a pitch exists in a direction perpendicular to the side edge between the outer light source and its nearest light source, and a distance between the low reflective portion and its corresponding outer light source is greater than one sixth of the pitch.

3. The backlight module of claim 1 , wherein a pitch exists in a direction perpendicular to the side edge between the outer light source and its nearest light source, and a width of the low reflective portion in the direction perpendicular to the side edge is less than one third of the pitch.

4. The backlight module of claim 2 , wherein in the direction parallel to the extending direction of the side edge, the normalized transmission ratio of the projection area is not greater than two third of the largest normalized transmission ratio of the projection areas along the direction parallel to the extending direction of the side edge.

5. The backlight module of claim 1 , wherein the second reflectance is not greater than 60%.

6. The backlight module of claim 1 , wherein the second reflectance is not greater than 60%, and the gloss rate of the low reflective portion is not greater than 30%.

7. The backlight module of claim 1 ,
wherein the low reflective portion includes a first reflection area and a second reflection area, the first reflection area is formed on the bottom area and the second reflection area is formed on the inclined area.

8. The backlight module of claim 1 , wherein the carrier plate comprises:
a carrier body; and
a reflective sheet disposed on the carrier body, wherein the reflectance of a surface of the reflective sheet facing away from the carrier body is greater than the reflectance of the carrier body,
wherein a plurality of holes are formed on the carrier body to expose part of the carrier body, the holes and the exposed part of the carrier body together form the low reflective portion.

9. The backlight module of claim 1 , wherein carrier plate comprises:
a carrier body; and
a reflective sheet disposed on the carrier body, wherein the reflectance of a surface of the reflective sheet facing away from the carrier body is greater than the reflectance of the carrier body,
wherein a plurality of light source holes are formed on the reflective sheet to accommodate the light sources, the light source holes accommodating the outer light sources have an area larger than the light source holes accommodating the other light sources to expose part of the carrier body.

10. The backlight module of claim 1 , wherein the modulation film has a plurality of blocks respectively corresponding to the light sources, the blocks include a plurality of outer blocks above the outer light sources and located at the outermost of the modulation film, the normalized transmission ratio of the light emitting structures in at least one of the outer blocks is based on the projection position corresponding to the outer light source as the center and increases progressively toward the outer side of the outer block based on a function value of a polynomial function.

11. The backlight module of claim 10 , wherein at least one of the outer blocks includes a preset area adjacent to the edge of the modulation film and the adjacent outer block, the normalized transmission ratio of the preset area is based on the projection position of the closest outer light source as the center and changes based on the function value of the polynomial function multiplied by a weighting value, wherein the weighting value is between 1.1 to 1.3.

12. The backlight module of claim 11 , wherein the preset areas of adjacent outer blocks together form an isosceles triangle with an apex angle toward the inner side of the modulation film.

13. A backlight module, comprising:
a carrier plate having a carrier surface with a first reflectance;
a plurality of light sources disposed on the carrier plate and surrounded by part of the carrier surface, the light sources including a plurality of outer light sources distributed along a side edge of the carrier surface;
a modulation film disposed above the light sources and having a plurality of light emitting structures, wherein the modulation film has a plurality of blocks respectively corresponding to the light sources, the blocks include a plurality of outer blocks above the outer light sources and located at the outermost of the modulation film, a normalized transmission ratio of the light emitting structures in the outer block is based on a projection position corresponding to the light source as the center and increases progressively toward the outer side of the outer block based on a function value of a polynomial function; and
a plurality of low reflective portions formed on the carrier surface and below the outer blocks, the low reflective portions have a second reflectance less than the first reflectance;
wherein each of the low reflective portions has a projection area within the outer blocks respectively, the projection area is between a projection position of the outer light source in the outer block and an edge of the modulation film parallel to the side edge; and
wherein the carrier surface comprises:
a bottom area having an end edge, wherein the outer light sources are disposed on the bottom area and adjacent to the end edge; and
an inclined area inclined from the end edge and extending outwardly toward the modulation film, wherein the inclined area is distributed along the side edge;
wherein at least part of the low reflective portion is formed on the inclined area.

14. The backlight module of claim 13 , wherein at least one of the outer blocks includes a preset area adjacent to the adjacent outer block and the edge of the modulation film, the normalized transmission ratio of the preset area is based on the projection position of the closest outer light source as the center and changes based on the function value of the polynomial function multiplied by a weighting value, wherein the weighting value is between 1.1

Assignees

• Au Optronics Corp

Inventors

• Ma Chi Tang
• Lin su yi
• Wang Ming Cheng
• Chung Wei Chun
• Yang Chen Hsun
• Huang jian li
• Chen Chung Ting

Classifications

• G02F1/133605

  including specially adapted reflectors · CPC title

• G02F1/133611

  including means for improving the brightness uniformity · CPC title

• G02F1/133606 Primary

  including a specially adapted diffusing, scattering or light controlling members · CPC title

• G02F1/133603

  with LEDs · CPC title

• G02F1/133608

  including particular frames or supporting means · CPC title