Assembly of a display device and an illumination system

• US 20010035853A1
• Filed: 04/19/2001
• Published: 11/01/2001
• Est. Priority Date: 05/04/2000
• Status: Abandoned Application

• Current Assignee: Lumilegs Lighting International B.V.
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Hoelen, Christoph Gerard August, Harbers, Gerard
• Application Number:
  US09/837,937
• Publication Number:
  US 20010035853A1
• Time in Patent Office: Days
• US Class Current: 345/102
• 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 2201/58 Arrangements comprising a monitoring photodetector
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/144 the light being ambient light
• 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 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127

Abstract

The system comprises a display device with a pattern of pixels (3) controlled by a control circuit (8) and a backlight system for illuminating the display device, which backlight system comprises a light-emitting panel and a light source (16, 16′, 16″, . . . ) associated with the light-emitting panel. The light source comprises a plurality of light-emitting diodes (LEDs) of at least two different colors. The control circuit (8) also controls the luminous flux of the LEDs. Preferably, the intensity of the light emitted by the LEDs (16, 16′, 16″) varies with the light level of the image to be displayed by the display device. Preferably, the intensity of the light emitted by the backlight system can be controlled on a frame-to-frame basis and, preferably, also for each color. Preferably, the LEDs comprise a plurality of red, green, blue (and amber) LEDs, each, preferably, having a luminous flux of at least 5 lumen. The color point of an image to be displayed on the display screen of the display device is set by the backlight system, enabling an optimum contrast to be obtained for the image to be displayed by the display device.

Claims

1. An assembly comprising

a display device provided with a pattern of pixels (3) driven by a control circuit (8),

and an illumination system for illuminating the display device,

said illumination system comprising a light-emitting panel (11) and at least one light source (16, 16′

, 16″

, . . . ), said light source (16, 16′

, 16″

, . . . ) being associated with the light-emitting panel (11), characterized in that

the light source comprises at least two light-emitting diodes (16, 16′

, 16″

, . . . ) having different light-emission wavelengths, and

the control circuit (8) also drives the luminous fluxes of the light-emitting diodes (16, 16′

, 16″

, . . . ) in dependence upon an image to be displayed by the display device.

2. An assembly as claimed in

claim 1

, characterized in that the control circuit (8) varies the intensities of the light emitted by the light-emitting diodes (16, 16′

, 16″

, . . . ) in response to the illumination level of the image to be displayed by the display device.

3. An assembly as claimed in

claim 1

or

2

, characterized in that the intensities of the light emitted by the light-emitting diodes (16, 16′

, 16″

, . . . ) can be adjusted on a frame-to-frame basis.

4. An assembly as claimed in

claim 1

or

2

, characterized in that the intensities of the light emitted by the light-emitting diodes (16, 16′

, 16″

, . . . ) can be adjusted for each color on a frame-to-frame basis.

5. An assembly as claimed in

claim 1

or

2

, characterized in that the light source comprises at least three light-emitting diodes (16, 16′

, 16″

, . . . ) having different light-emission wavelengths.

6. An illumination system as claimed in

claim 1

or

2

, characterized in that each of the light-emitting diodes (16, 16′

, 16″

, . . . ) comprises a luminous flux of at least 5 lm.

7. An illumination system as claimed in

claim 6

, characterized in that the light-emitting diodes (16, 16′

, 16″

, . . . ) are mounted on a printed circuit board.

8. A display device for use in an assembly as claimed in

claim 1

or

2

.

9. An illumination system for use in an assembly as claimed in

claim 1

or

2

.