LED backlighting for liquid crystal display (LCD)

• US 8,188,957 B2
• Filed: 07/15/2011
• Issued: 05/29/2012
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Xenogenic Development Limited Liability Company (Intellectual Ventures LLC)
• Original Assignee: Money Park Investments Limited
• Inventors: Hu, Darwin, Li, Kebin
• Primary Examiner(s): ABDULSELAM, ABBAS I
• Application Number:
  US13/183,429
• Publication Number:
  US 20120026212A1
• Time in Patent Office: 319 Days
• Field of Search: 345/88, 345/89, 345/98, 345/99, 345/100, 345/102, 345/204, 345/690, 345/694, 349/108, 349/109, 382/167
• US Class Current: 345/88
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G09G 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

Techniques for providing LED-based backlighting in liquid crystal flat panel displays are disclosed. In one embodiment, the backlighting includes at least three color groups of light emitting diodes (LEDs) that are turned on successively for one frame of image. Liquid crystals (pixels) in an LCD are controlled in accordance with a display signal to transmit none, all or a determined amount of one or more of the colored lights from the three color groups of light emitting diodes in a cycle, resulting in an LCD with vivid colors and minimized tailing effects.

Claims

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

a backlighting unit including at least three groups of light emitting diodes (LEDs), the LEDs in each of the groups being in one type of color, the groups of the LEDs tuned on successively in a cycle and synchronized with at least a video signal coupled from a video processor receiving a display signal to be displayed on the liquid crystal display panel; and

a liquid crystal display panel including a plurality of pixels controlled by liquid crystals, each of the pixels including no further subpixels and reproducing a perceived color from a combined illumination from the at least three groups of LEDs, wherein at least three colored lights from the at least three groups of LEDs are transmitted successively through a corresponding liquid crystal, an amount of each of the at least three colored lights is controlled in accordance with the display signal.

2. The liquid crystal display device of claim 1, further comprising a controller provided to control the LEDs in each of the at least three groups in accordance with the display signal, where the controller is coupled to the video processor to receive synchronization signals in the display signal.

3. The liquid crystal display device of claim 1, further comprising one or more drivers to control the pixels in the liquid crystal display panel in accordance with the display signal.

4. The liquid crystal display device of claim 1, further comprising one or more drivers to control the liquid crystal of each of the pixels such that an amount of lighting passing through the liquid crystal is controlled in accordance with the display signal.

5. The liquid crystal display device of claim 1, further comprising one or more drivers to control the liquid crystal of each of the pixels such that a duration of the liquid crystal is turned on to allow a predefined amount of light passing through the liquid crystal is controlled to achieve a perceived color.

6. The liquid crystal display device of claim 1, further comprising one or more drivers to control the liquid crystal of each of the pixels such that an amount of lighting passing through the liquid crystal is determined in the cycle, wherein the one or more drivers also control the liquid crystal of each of the pixels such that respective durations of the liquid crystal sequentially turned on to allow a corresponding type of light passing through the liquid crystal are determined in the cycle.

7. The liquid crystal display device of claim 1, wherein the at least three groups of light emitting diodes (LEDs) include red (R), green (G) and blue (B) color groups.

8. The liquid crystal display device of claim 7, wherein the LEDs in each of the at least three groups have predefined offsets in wavelengths or colors.

9. The liquid crystal display device of claim 8, wherein the some offsets in wavelengths or colors are to ensure that colors in a predefined visible spectrum are substantially reproduced.

10. The liquid crystal display device of claim 9, wherein the predefined visible spectrum is a superset of colors defined in accordance with a TV standard.

11. The liquid crystal display device of claim 7, further comprising sensors to sense respective colors from the red (R), green (G) and blue (B) color groups, signals from the sensors is fed back to a controller to control the light emitting diodes in accordance with a predetermined power ratio for the light emitting diodes in the red (R), green (G) and blue (B) color groups.

12. A liquid crystal display (LCD) device comprising:

a backlighting unit including three colored groups of light emitting diodes (LEDs);

a controller controlling the three colored groups of LEDs in accordance with sensor signals from sensing respective lights from the three colored groups of LEDs; and

a liquid crystal display panel including a plurality of pixels, each of the pixels including no further subpixels and reproducing a perceived color from a combined illumination produced by the three colored groups of LEDs—

through a corresponding liquid crystal in a specified amount, wherein the three colored groups of LEDs are turned on and off sequentially in a cycle synchronized with a display signal to be displayed on the liquid crystal display panel, an illumination from each of the three colored groups of LEDs is substantially evenly distributed to one side of the liquid crystal display panel by at least a light guide and a diffuser.

13. The liquid crystal display device of claim 12, further comprising a set of sensors configured to sense respective colored lights and provide one or more of the sensor signals.

14. The liquid crystal display device of claim 12, further comprising one or more drivers to control the pixels in the liquid crystal display panel in accordance with the display signal.

15. The liquid crystal display device of claim 14, further comprising one or more drivers to control the liquid crystal of each of the pixels such that an amount of light passing through the liquid crystal is controlled in accordance with the display signal.

16. The liquid crystal display device of claim 14, further comprising one or more drivers to control the liquid crystal of each of the pixels such that a duration of the liquid crystal is turned on to allow a predefined amount of light passing through the liquid crystal is controlled in accordance with the display signal.

17. The liquid crystal display device of claim 14, further comprising one or more drivers to control the liquid crystal of each of the pixels such that an amount of light passing through the liquid crystal is determined in the cycle.

18. The liquid crystal display device of claim 17, wherein the amount of light passing through the liquid crystal in a controlled way together with durations controlled for respective types of lighting passing through the liquid crystal are capable to reproduce millions of perceived colors.