METHOD FOR MAINTAINING THE WHITE COLOUR POINT IN A FIELD-SEQUENTIAL LCD OVER TIME
First Claim
1. A method for maintaining a colour point for a plurality of light emitting elements used to illuminate a display of an electronic device, comprising:
- determining a first value corresponding to activation data of each element of said plurality of light emitting elements, the activation data corresponding to one of the total time the light source has been activated and a function of activation time and an intensity value of the plurality of light emitting elements;
identifying a compensation value for aging of said each element based on said first value;
adjusting an output to produce said colour on said display by adjusting an intensity for each said element utilizing its compensation value; and
for a grey scale image to be generated on said display, at a pixel of said displaysetting said pixel to a transmissive state if said grey scale image at said pixel includes a colour to be activated; and
not turning on said pixel if said grey scale image at said pixel does not include said colour.
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Accused Products
Abstract
A field sequential liquid crystal display maintains its white colour point through compensation values to at least one colour light emitting diode that illuminates the display. The compensation values may be impedances to control the current or pulsing of the current source according to a pulse width modulation technique. A degradation curve may be used to calculate extrapolate the theoretical forward voltage of the light emitting diode. Additional complexity arises from the need for calculating uptime for multiple light emitting diodes of different colours. Brightness levels may also be factored in. Additional processing of a display element may be provided when a grey scale image is being generated.
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Citations
20 Claims
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1. A method for maintaining a colour point for a plurality of light emitting elements used to illuminate a display of an electronic device, comprising:
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determining a first value corresponding to activation data of each element of said plurality of light emitting elements, the activation data corresponding to one of the total time the light source has been activated and a function of activation time and an intensity value of the plurality of light emitting elements; identifying a compensation value for aging of said each element based on said first value; adjusting an output to produce said colour on said display by adjusting an intensity for each said element utilizing its compensation value; and for a grey scale image to be generated on said display, at a pixel of said display setting said pixel to a transmissive state if said grey scale image at said pixel includes a colour to be activated; and not turning on said pixel if said grey scale image at said pixel does not include said colour. - View Dependent Claims (2, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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3. The method of claim 3, wherein the function includes a sum of a plurality of intensity products, wherein each product of said plurality of products is an activation time of the light emitting elements multiplied by intensities during the activation time.
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13. A field sequential liquid crystal display system that compensates for white colour point drift over time, comprising:
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a liquid crystal display; a light emitting element for illuminating the liquid crystal display, the white colour point drift of the liquid crystal display being compensated through compensation applied to the light emitting element; a first module operating characteristics of said light emitting element to identify a compensation element to compensate for aging of said light emitting element; and a second module to adjust an intensity of an output of said light emitting element to compensate for said white colour point drift by adjusting an intensity of activation of said light emitting element by utilizing said compensation element; and a third module to set a transmissivity state for a pixel in said display when said display is generating a colour selected from one of red, green and blue for a grey scale image, said state selected from one of; a transmissive state if said grey scale image at said pixel includes said colour; and a not turned on state at said pixel if said grey scale image at said pixel does not include said colour. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification