Ultra-Thin Backlight

• US 20080151576A1
• Filed: 12/18/2007
• Published: 06/26/2008
• Est. Priority Date: 05/16/2001
• Status: Active Grant

• Current Assignee: Benzion Inditsky
• Original Assignee: Benzion Inditsky
• Inventors: Inditsky, Benzion
• Granted Patent: US 7,815,358 B2
• Time in Patent Office: Days
• US Class Current: 362/615
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A backlight for a display device, such as a liquid crystal display device, includes a light guiding plate having a front and a rear surface. The front and rear surfaces may be parallel to one another, or may instead be non-parallel. To the extent that such surfaces are non-parallel, one surface may be inclined at a single, or multiple angles with respect to the other surface. The backlight further includes a light source that is coupled to an edge of the light guiding plate by means of an energy conserving coupling section, and which provides light that is conditioned and transmitted through the light guiding plate. Light extractors are disposed on at least one side of the light guiding plate to assist in the transmission and conditioning of the light that is provided to the light guiding plate by the light source.

Claims

1. An apparatus for use with a display device comprising:

a wave guide having first and second major surfaces, the first major surface being disposed proximate to the display device and the second surface including a doubly curved wedge light guiding arrangement;

at least one light source coupled to the wave guide;

a light extraction device disposed integrally to one of the surfaces; and

a reflector disposed proximate to at least one of the surfaces.

2. The apparatus of claim 1 including a focon disposed between the at least one light source and the wave guide.

3. An apparatus comprising:

a display device;

a wave guide having a first surface disposed proximate to the display device and a second surface including doubly curved wedge light guiding arrangement;

at least one light source;

at least one foconic coupling arrangement disposed between the light source and the wave guide;

a light extraction device integrally disposed along at least one said surfaces of the wave guide; and

a reflector disposed proximate to the wave guide wherein light is injected into the focon by the light source in a first direction, exits the focon in a second direction, and exits the wave guide in a third direction.

4. A liquid crystal display device comprising:

a liquid crystal display module;

a backlight structure including;

a light source,

a wave guide including light extractors formed therein,

a focon disposed between the light source and the wave guide,

a reflector disposed proximate to the focon, wherein light is injected into the focon by the light source in a first direction, exits the focon in a second direction and exits the wave guide in a third directions.

5. The liquid crystal display device of claim 4 wherein said focon is integrally formed with a major surface of the wave guide.

6. The liquid crystal display device of claim 4 wherein said focon is integrally formed with the light source.

7. The liquid crystal display device of claim 6 wherein the wave guide has at least one generally cylindrical cut-out forming edge.

8. The liquid crystal display device of claim 4 wherein said light source is a RGB LED.

9. The liquid crystal display device of claim 4 wherein the focon includes a central crater section having a reduced thickness and the fecon has a compound elliptic-hyperbolic shape.

10. The liquid crystal display device of claim 6 wherein the focon includes edges being formed by a generally cylindrical surface around about aligned with an apex of the focon.

11. The liquid crystal display device of claim 4 wherein the focon has an asymmetrical shape about disposed at an apex axis.

12. The liquid crystal display device of claim 4 wherein an angle between a horizontal XY plane and a line connecting an apex of the focon and a distant point on a boundary of the light source is equal or smaller than a predetermined quantity minus a critical TIR angle of the focon.

13. The liquid crystal device of claim 4 wherein an angle between a horizontal XY plane and a line connecting any point on the upper circumference of the focon and any point on a proximate boundary of the light source is equal or larger than a predetermined quantity minus a critical TIR angle of the focon.

14. The liquid crystal display device of claim 4 wherein said light source is immersed in the wave guide.

15. The liquid crystal display device of claim 4 wherein said focon is reduced to a planar reflector adjacent to an upper surface of the wave guide.

16. The liquid crystal display device of claim 4 including light extracting regions having a pattern with a density which varies over each surface.

17. The liquid crystal device of claim 4 wherein the surface includes a density pattern having a variation being generally a function of both of its coordinate axes with an origin about at a center of the focon.

18. The liquid crystal device of claim 4 wherein the waveguide has an arbitrary contour.