Liquid crystal display with colored backlight

• US 7,602,369 B2
• Filed: 10/15/2004
• Issued: 10/13/2009
• Est. Priority Date: 05/04/2004
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Daly, Scott J., Feng, Xiao-fan, Messing, Dean
• Primary Examiner(s): Nguyen; Chanh
• Assistant Examiner(s): Snyder; Adam J
• Application Number:
  US10/966,257
• Publication Number:
  US 20050248524A1
• Time in Patent Office: 1,824 Days
• Field of Search: 345 87-104, 345/83, 345/694, 345/204, 349/61, 315/291
• US Class Current: 345/102
• 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 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

A method of backlighting a liquid crystal display so as to improve the quality of the image displayed by the liquid crystal display. The method may vary the luminance of a light source illuminating a plurality of displayed pixels and vary the transmittance of a light valve of the display.

Claims

1. A method of illuminating a backlit display, said method comprising the step of varying the luminance of a light source illuminating a plurality of displayed pixels and varying the transmittance of a light valve of said display in a non-binary manner, wherein said light source is spatially displaced at a location at least partially directly beneath said plurality of pixels, and wherein said light source includes a plurality of different colored light emitting diodes wherein light emitted from said plurality of different colored light emitting diodes passes through respective color filters prior to passing through a respective said light valve, and a plurality of non-colored white light emitting diodes, where the plurality of different colored light emitting diodes collectively have a color gamut greater than that of the non-colored white light emitting diodes and wherein at least one of said color filters has a filter value based on the respective difference between the color gamut of said non-colored white light emitting diode and the collective said color gamut of said colored light emitting diodes.