Display with focussed illumination
View Patent ↗A liquid crystal display with focused illumination is described. In an example, a light-source emitting a plurality of discrete colors is focused onto a liquid crystal display panel. The liquid crystal display panel has a plurality of pixels and each pixel has regions corresponding to the colors emitted by the light-source. Light of each color is focused onto the regions of the pixels corresponding to that color.
1. A display apparatus, comprising:
a backlight emitting a plurality of discrete colors of light;
a liquid crystal panel comprising a plurality of pixels, each pixel having a plurality of regions, each region corresponding to one of the colors emitted by the backlight;
a focusing element that is a lenslet array having a plurality of lenslets configured to focus light of a particular color emitted by the backlight onto a particular pixel corresponding to the particular color;
a tapered light-guide to guide light from the backlight to the focusing element, the tapered light-guide positioned to eject light from a face of the tapered light-guide to the focusing element; and
a pitch of the lenslet array is coarser at an end that first receives the light from the tapered light-guide.
2. A display apparatus according to claim 1 , wherein the colors are red, green and blue.
3. A display apparatus according to claim 1 , wherein the lenslets of the lenslet array are columns to focus the light in a plane perpendicular to the columns.
4. A display apparatus according to claim 3 , wherein the plurality of pixels are arranged in pixel columns such that one pixel column corresponds to one of the lenslets.
5. A display apparatus according to claim 1 , wherein the backlight comprises a plurality of groups of light-sources, each group emitting at least one of the colors.
6. A display apparatus according to claim 1 , further comprising one or more mirrors arranged in a plane perpendicular to the liquid crystal panel between the backlight and the focusing element.
7. A display apparatus according to claim 1 , wherein the lenslets of the lenslet array focus light on at least two pixels.
8. A display apparatus according to claim 1 , further comprising the backlight being arranged to inject light into a thick-end of the tapered light-guide.
9. A display apparatus according to claim 1 , further comprising a prismatic sheet between the face of ejection of the tapered light-guide and the focusing element such that light enters the focusing element perpendicular to a plane of the focusing element.
10. A display apparatus according to claim 1 , wherein the tapered light-guide comprises a tapered region and an extension region, wherein the extension region extends from a thick end of the tapered region.
11. A display apparatus according to claim 10 , wherein the tapered light-guide is a folded light-guide and comprises a prismatic region to guide light around the folded light-guide.
12. A display apparatus according to claim 1 , wherein a focal length of the lenslets of the lenslet array is shorter at the end that first receives the light from the tapered light-guide.
13. A display apparatus according to claim 1 , wherein:
the backlight comprises a plurality of groups of light-sources; and
the backlight is configured to selectively reduce an intensity of one or more groups of the plurality of groups of light-sources in regions where an image is intended to be dark.
14. A display apparatus, comprising:
a backlight emitting red, green and blue light;
a liquid crystal panel comprising a plurality of pixels, each pixel comprising red, green and blue regions;
a lenslet array having a plurality of lenslets configured to focus a particular color of the red, green or blue light onto at least one particular pixel; and
one or more mirrors arranged in a plane perpendicular to the liquid crystal panel between the backlight and the lenslet array.
15. A display apparatus, comprising:
a backlight comprising red, green and blue light-sources;
a liquid crystal display comprising a plurality of pixels arranged in columns, each pixel comprising red, green and blue regions;
a lenslet array comprising a plurality of lenslet columns, wherein the lenslet array focuses light from the red, green and blue light-sources onto columns of regions corresponding to the color of the light-source; and
one or more mirrors arranged in a plane perpendicular to the liquid crystal panel between the backlight and the lenslet array.