LED backlighting system

• US 6,930,737 B2
• Filed: 12/28/2001
• Issued: 08/16/2005
• Est. Priority Date: 01/16/2001
• Status: Expired due to Term

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Weindorf, Paul F. L., Zysnarski, Adam
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): DIAZ, JOSE R
• Application Number:
  US10/040,864
• Publication Number:
  US 20020140880A1
• Time in Patent Office: 1,327 Days
• Field of Search: 349/64, 349/67, 349/96, 349/112, 349/113, 349/149, 349/150, 349/61, 349/98, 349 69- 70, 349/60
• US Class Current: 349/96
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• 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 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: G02B 6/0085 Means for removing heat created by the light source from the package heat extraction or cooling elements for semiconductor light sources in general H01L33/64
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/52 in a parallel array of LEDs
• CPC Class Codes: H05B 45/56 involving measures to prevent abnormal temperature of the LEDs

Abstract

A liquid crystal display (LCD) device having non-white and white light emitting diodes and a liquid crystal display. A spectrum converting material is positioned between non-white LEDs and the LCD to convert the non-white light from the LEDs toward a white light spectrum. The liquid crystal display may include a plurality of light emitting diodes, a light pipe, and a spectrum converting material. The spectrum converting material may be a phosphorized material located between the plurality of non-white light emitting diodes and the light pipe. A light extracting surface may be located near a first surface of the light pipe, a diffuser located near a second side of the light pipe, where the first and second sides are opposite sides of the light pipe, a reflective polarizer, and an liquid crystal display. The light from the light pipe may passes through the diffuser, the reflective polarizer, before backlighting the liquid crystal display. The non-white LEDs may include blue LED, ultraviolet LEDs, and the like.

Claims

1. A liquid crystal display (LCD) device, comprising:

a white light emitting diode;

a light pipe;

a light extracting surface located near a first side al the light pipe;

a diffuser located near a second side of the light pipe, where the first and second sides are opposite sides of the light pipe;

a reflective polarizer;

a liquid crystal display;

a first polarization scrambling material located along the light pipe opposite the liquid crystal display;

a second polarization scrambling material between the white light emitting diode and the light pipe; and

wherein light from the white light emitting diode enters the light pipe and passes through the diffuser, the reflective polarizer, then backlights the liquid crystal display.

2. The LCD device of claim 1, wherein the white light emitting diode is located along a perimeter of a circuit board.

3. The LCD device of claim 2, wherein the circuit board comprises a flexible circuit board.

4. The LCD device of claim 2, further comprising a thermally conductive material between the circuit board and a frame.

5. The LCD device of claim 2, wherein the white light emitting diode has a top reflective orientation with the light pipe.

6. The LCD device of claim 2, wherein the white light emitting diode has a side reflective orientation with the light pipe.

7. The LCD device of claim 1, wherein the second polarization scrambling material forms apertures near the white light emitting diode.

8. The LCD device of claim 1, wherein the first polarization scrambling material comprises an enhanced diffuser reflector.

9. The LCD device of claim 1, further comprising an enhanced specular reflector disposed near the white light emitting diode and the light pipe, where light form the white light emitting diode reflects from the enhanced specular reflector into the light pipe.