Light guide plates having a two-dimensional pattern comprising substantially identical micro-lenses

• US 8,602,628 B2
• Filed: 12/09/2011
• Issued: 12/10/2013
• Est. Priority Date: 12/09/2011
• Status: Expired due to Fees

• Current Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Original Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Inventors: Mi, Xiang-Dong, Lee, Ju-Hyun
• Primary Examiner(s): Hanley, Britt D
• Application Number:
  US13/316,122
• Publication Number:
  US 20130148378A1
• Time in Patent Office: 732 Days
• Field of Search: None
• US Class Current: 362/616
• CPC Class Codes: G02B 3/0043 Inhomogeneous or irregular arrays, e.g. varying shape, size, height
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity

Abstract

The present invention provides a light guide plate comprising an input surface for receiving light from a plurality of discrete light sources, an output surface for emitting light, and a bottom surface opposing to the output surface, wherein at least one of the output surface and the bottom surface has a micro-pattern, the micro-pattern consisting of a plurality of substantially identical micro-lenses, each micro-lens having a width, a length, and an orientation angle. The light guide plate further provides an area density D(x, y) of the micro-lenses varies in a first direction y-axis that is parallel to the length direction and in a second direction x-axis that is parallel to the width direction for y between starting line y0 and ending line, the area density D(x, y=y0) at the starting line y0 varying between a minimal value Dmin and a maximum value Dmax such that Dmin≧1% and 100≧Dmax/Dmin≧2, and wherein the area density D(x,y) repeats in pitch P in the x-axis such that D(x,y)=D(x+P,y).

Claims

1. A light guide plate comprising:

an input surface for receiving light from a plurality of discrete light sources, an output surface for emitting light, and a bottom surface opposing to the output surface,

wherein at least one of the output surface and the bottom surface has a micro-pattern, the micro-pattern consisting of a plurality of substantially identical micro-lenses, each micro-lens having a width, a length, and an orientation angle; and

wherein an area density D(x, y) of the micro-lenses varies in a first direction y-axis that is parallel to the length direction and in a second direction x-axis that is parallel to the width direction for y between starting line y0 and ending line, the area density D(x, y=y0) at the starting line y0 varying between a minimal value Dmin and a maximum value Dmax such that Dmin≧

1% and 100≧

Dmax/Dmin≧

2, and wherein the area density D(x,y) repeats in pitch P in the x-axis such that D(x,y)=D(x+P,y).

2. The light guide plate of claim 1, wherein the variation of the width, length and depth of the plurality of micro-lenses is within 1.8 percent.

3. The light guide plate of claim 1, wherein the variation of the orientation angle of the plurality of micro-lenses is within 2 degrees.

4. The light guide plate of claim 1, wherein at the ending line the area density D(x,y) converges to a density function that only varies in the y-axis.

5. The light guide plate of claim 1, wherein the length between the ending line and starting line is L_2D, and the ratio L_2D/P is less than and equal to 0.75.

6. A backlight unit comprising a plurality of LEDs and a light guide plate, wherein the light guide plate comprises:

an input surface for receiving light from a plurality of discrete light sources, an output surface for emitting light, and a bottom surface opposing to the output surface,

wherein at least one of the output surface and the bottom surface has a micro-pattern, the micro-pattern consisting of a plurality of substantially identical micro-lenses, each micro-lens having a width, a length, and an orientation angle; and

wherein an area density D(x, y) of the micro-lenses varies in a first direction y-axis that is parallel to the length direction and in a second direction x-axis that is parallel to the width direction for y between starting line y0 and ending line, the area density D(x, y=y0) at the starting line y0 varying between a minimal value Dmin and a maximum value Dmax such that Dmin≧

1% and 100≧

Dmax/Dmin≧

2, and wherein the area density D(x,y) repeats in pitch P in the x-axis such that D(x,y)=D(x+P,y).

7. The backlight unit of claim 6 further comprising a top reflective film covering the beginning line of the area density D(x,y).