METHOD FOR REDUCING HOT SPOTS IN LIGHT GUIDE PLATES

• US 20130329452A1
• Filed: 06/12/2012
• Published: 12/12/2013
• Est. Priority Date: 06/12/2012
• Status: Abandoned Application

• Current Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Original Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Inventors: MI, Xiang-Dong
• Application Number:
  US13/494,926
• Publication Number:
  US 20130329452A1
• Time in Patent Office: Days
• US Class Current: 362/606
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity

Abstract

The present invention provides a method of reducing hot spots in a light guide plate, the light guide plate comprising an input surface for receiving light from a plurality of discrete light sources, an output surface for emitting light, a bottom surface opposing to the output surface, and an end surface opposing to the input surface. The method further provides distributing a set of lenses in the core zone and a set of micro-lenses in the mixing zone, wherein the density of the set of micro-lenses stays constant in the X-axis, and a size and density of the micro-lenses is selected to redirect the light from the discrete light sources toward the Y-axis and provide a ratio L₁/L₀ that is between 0.9 and 1.1 for any Y≧Y₁.

Claims

1. A method of reducing hot spots in a light guide plate, the light guide plate comprising:

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

wherein the direction from the input surface to the end surface is defined as Y-axis, the direction that is perpendicular to the Y-axis and parallel to the discrete light sources is defined as X-axis, the output surface having a plurality of elongated grooves running parallel to the Y-axis and extending from the input surface corresponding to Y=0 to the end surface, the bottom surface having a core zone extending from a predetermined line corresponding to Y=Y₁ to the end surface and a mixing zone extending from Y=0 to Y=Y₁; and

distributing a set of lenses in the core zone and a set of micro-lenses in the mixing zone, wherein the density of the set of micro-lenses stays constant in the X-axis, and a size and density of the micro-lenses is selected to redirect the light from the discrete light sources toward the Y-axis and provide a ratio L₁/L₀ that is between 0.9 and 1.1 for any Y≧

Y₁.

2. The method of claim 1, wherein the size of the set of micro-lenses is smaller than that of the set of lenses.

3. The method of claim 1, wherein the density of the set of micro-lenses is larger than that of the set of lenses distributed between Y=Y₁ and Y=2Y₁.

4. The method of claim 1, wherein the set of micro-lenses are distributed between Y=2 mm and Y=Y₁, but not between Y=0 and Y=2mm.

5. The method of claim 1, wherein the density of the set of micro-lenses varies along the Y-axis.

6. The method of claim 1, wherein the density of the set of micro-lenses remains the same along the Y-axis.

7. The method of claim 1, wherein the elongated grooves are linear prisms, linear trapezoids, or lenticular lenses.

8. The method of claim 1, wherein the ratio of the height to size of the elongated grooves is between 0.012 and 0.3298.

9. The method of claim 1, wherein the size of the micro-lenses is between 30 μ

m and 60 μ

m, and the density of the micro-lenses is between 10% and 20%.

10. The method of claim 1, wherein the ratio L₁/L₀ is between 0.9 and 1.1 for any Y between Y₀ and Y₁.