Backlight Modulation For Display

US 20080094426A1

(75) Inventor: Tom Kimpe, Gent (BE)

Correspondence Address:
BACON & THOMAS, PLLC
625 SLATERS LANE
FOURTH FLOOR
ALEXANDRIA, VA 22314

(73) Assignee: BARCO N.V., Kortrijk (BE)

(21) Appl. No.: 11/665,783

(22) PCT Filed: Oct. 25, 2005 (86) PCT No.: PCT/EP05/11419

§ 371(c)(1),

(2), (4) Date: Apr. 19, 2007 (30) Foreign Application Priority Data

Oct. 25, 2004 (EP) 04447237.1

(51) Int. CI.

G09G 5/10 (2006.01)

(52) U.S. CI 345/691; 345/690

(57) ABSTRACT

A display (10) has a non pixel addressable backlight (130), having a temporal modulation applied, a pixel addressable LCD (120) in an optical path and the pixel addressable part being arranged to output each pixel of a frame as a temporal sequence of output values unrelated to colour components of the pixel, different values of the sequence coinciding with different output levels of the modulated non pixel addressable part. The apparent luminance or colour of the pixels can be made to take intermediate values between the gradations dictated by the stepsize corresponding to a least significant bit of the pixel addressable part, to enable more accurate reproduction of both colour and greyscale images. Additional intermediate output levels are concentrated at low illumination levels. A converter generates a temporal modulation of the pixels for the LCD according to a value of the pixels in an input signal, and synchronized to the temporal modulation of the backlight.