LIGHT GUIDE PLATE HAVING A REVERSED MICRO-PATTERN IN ITS MIXING ZONE

• US 20130329453A1
• Filed: 06/12/2012
• Published: 12/12/2013
• Est. Priority Date: 06/12/2012
• Status: Active Grant

• Current Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Original Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Inventors: MI, Xiang-Dong
• Granted Patent: US 8,613,540 B1
• Time in Patent Office: Days
• US Class Current: 362/606
• CPC Class Codes: G02B 6/0011 the light guides being planar or of plate-like form
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• 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 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

The present invention provides a light guide plate having reduced hot spots 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.

Claims

1. A light guide plate having reduced hot spots 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 has 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 has 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

a set of lenses are distributed in the core zone and a set of micro-lenses distributed in the mixing zone between Y=Y₀ and Y=Y₁, wherein the density of the set of micro-lenses varies in the X-axis, having a maximum value at a first location that has a same X value as the center of one of the discrete light sources, and having a minimum value at a second location that has a same X value as the center of two adjacent discrete light sources, and the selected size and the density of the micro-lenses redirect the light from the discrete light sources toward the Y-axis and the ratio L₁/L₀ is between 0.9 and 1.1 for any Y≧

Y₁.

2. The light guide plate of claim 1, wherein another set of micro-lenses are distributed in the mixing zone between Y=0 and Y=Y₀, the density of the another set of micro-lenses varying in the X-axis, having a minimum value at the first location and having a maximum value at the second location.

3. The light guide plate of claim 1, wherein the density of the set of micro-lenses varies in the Y-axis.

4. The light guide plate of claim 1, wherein the density of the set of micro-lenses is constant in the Y-axis.

5. The light guide plate of claim 1, wherein the size of the set of micro-lenses is smaller than that of the set of lenses.

6. The light guide plate of claim 1, wherein the elongated grooves are linear prisms, linear trapezoids, or lenticular lenses.

7. The light guide plate of claim 1, wherein the ratio of the height to size of the elongated grooves is between 0.012 and 0.3298.