Balanced LED backlighting for liquid crystal display (LCD)
First Claim
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1. A liquid crystal display (LCD) device comprising:
- a backlighting unit comprising a first light source of a first color, a second light source of a second color, and a third light source of a third color, the backlighting unit configured to illuminate, in a cycle, the first light source during a first time in the cycle, the second light source during a second time in the cycle, and the third light source during a third time in the cycle;
a liquid crystal display panel comprising a plurality of pixels, wherein ones of the plurality of pixels are configured to permit passage of a percentage of light of the first color during the first time in the cycle, a percentage of light of the second color during the second time in the cycle, and a percentage of light of the third color during the third time in the cycle;
at least one first optical sensor configured to sense at least one characteristic of each of the respective illuminations of the first color, the second color, and the third color;
at least one second optical sensor configured to sense at least one characteristic of the combined light from illuminations of the first color, the second color, and the third color; and
a controller configured to receive feedback signals from the at least one first optical sensor and the at least one second optical sensor, the controller configured to control the first light source, the second light source, and the third light source based on the feedback signals.
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Abstract
Techniques for providing LED-based backlighting in liquid crystal flat panel displays are disclosed. In one embodiment, optical sensors are provided to sense illuminations from colored LED groups and provide feedback signals to a controller so that a desired ratio of the illuminations is maintained. As a result, true colors could be reproduced regardless of possible irregularities that may be happening to LEDs used in the colored LED groups to backlight an LCD panel.
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Citations
20 Claims
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1. A liquid crystal display (LCD) device comprising:
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a backlighting unit comprising a first light source of a first color, a second light source of a second color, and a third light source of a third color, the backlighting unit configured to illuminate, in a cycle, the first light source during a first time in the cycle, the second light source during a second time in the cycle, and the third light source during a third time in the cycle; a liquid crystal display panel comprising a plurality of pixels, wherein ones of the plurality of pixels are configured to permit passage of a percentage of light of the first color during the first time in the cycle, a percentage of light of the second color during the second time in the cycle, and a percentage of light of the third color during the third time in the cycle; at least one first optical sensor configured to sense at least one characteristic of each of the respective illuminations of the first color, the second color, and the third color; at least one second optical sensor configured to sense at least one characteristic of the combined light from illuminations of the first color, the second color, and the third color; and a controller configured to receive feedback signals from the at least one first optical sensor and the at least one second optical sensor, the controller configured to control the first light source, the second light source, and the third light source based on the feedback signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A liquid crystal display (LCD) device comprising:
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a backlighting unit including three colored groups of at least one light source that are illuminated successively in a cycle; three sensors configured to sense illuminations from each of the three colored groups of at least one light source; at least one sensor configured to sense illuminations of all of the three colored groups of at least one light source over at least one cycle; a controller, configured to receive control signals from the three sensors and the at least one sensor and further configured to control the three colored groups of at least one light source to keep a desired ratio of the illuminations from the three colored groups of at least one light source; and a liquid crystal display panel including a plurality of pixels, wherein ones of the plurality of pixels are configured to permit passage of an amount of light illuminated from each of the three colored groups of at least one light source. - View Dependent Claims (12, 13, 14)
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15. A method for use with a liquid crystal display device, comprising:
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illuminating light through a plurality of pixels in the liquid crystal display device in a cycle, the illuminating comprising; illuminating a first light source of a first color during a first time in the cycle and permitting passage of an amount of the illuminated light of the first color through ones of the plurality of pixels, illuminating a second light source of a second color during a second time in the cycle and permitting passage of an amount of the illuminated light of the second color through ones of the plurality of pixels, and illuminating a third light source of a third color during a third time in the cycle and permitting passage of an amount of the illuminated light of the third color through ones of the plurality of pixels; sensing, by at least one first optical sensor, at least one characteristic of each of the respective illuminations of the first color, the second color, and the third color; sensing, by at least one second optical sensor, at least one characteristic of the combined light from illuminations of the first color, the second color, and the third color; and controlling the illumination of each of the first light source, the second light source, and the third light source based on feedback signals generated by the at least one first optical sensor and the at least one second optical sensor. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification