WHITE BACKLIGHT FOR A DISPLAY
First Claim
1. A display backlight to produce white light of a specified color point, comprising an arrangement of light sources, the chromaticities of which are selected from a group of at least three different chromaticities, the light sources coupled to an arrangement for transmitting the light emitted from the light sources to further display components, which arrangement mixes the emitted light to produce white light of the specified color point, wherein the chromaticity coordinates of the group of at least three different chromaticities, when plotted on the CIE 1976 U.S.C. Chromaticity Diagram, form the vertices of a shape with at least three sides which shape further surrounds the point on the diagram which describes the specified color point, characterised in that the red wavelengths emitted by the light sources are emitted by light sources of two or more chromaticities from the group of at least three different chromaticities and arranged to be driven with the result that visible, red-colored artifacts are reduced at boundaries of high image contrast when the backlight is coupled to further display components and used for display of a grey scale image.
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Abstract
A display backlight is described which produces white light of a specified color point and from light sources of different chromaticities and in which the red wavelengths emitted by the light sources are emitted by light sources of two or more chromaticities from the group of at least three different chromaticities and arranged to be driven with the result that visible, red-colored artifacts are reduced at boundaries of high image contrast when the backlight is coupled to further display components and used for display of a grey scale image. The invention allows production of a display with an adjustable white color point but which also does not suffer from distracting red, fringe-like artefacts reported by users of displays comprising white backlights produced from red, green and blue light sources. A display incorporating the backlight is also described.
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Citations
20 Claims
- 1. A display backlight to produce white light of a specified color point, comprising an arrangement of light sources, the chromaticities of which are selected from a group of at least three different chromaticities, the light sources coupled to an arrangement for transmitting the light emitted from the light sources to further display components, which arrangement mixes the emitted light to produce white light of the specified color point, wherein the chromaticity coordinates of the group of at least three different chromaticities, when plotted on the CIE 1976 U.S.C. Chromaticity Diagram, form the vertices of a shape with at least three sides which shape further surrounds the point on the diagram which describes the specified color point, characterised in that the red wavelengths emitted by the light sources are emitted by light sources of two or more chromaticities from the group of at least three different chromaticities and arranged to be driven with the result that visible, red-colored artifacts are reduced at boundaries of high image contrast when the backlight is coupled to further display components and used for display of a grey scale image.
Specification