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;
comparing the first value against a first threshold to identify a compensation value for aging of said each element;
comparing the first value against a second threshold if the first value exceeds the first threshold;
if the first value is between said first and said second thresholds, then utilizing a first compensation value for said compensation value for the plurality of light emitting elements;
if the first value exceeds the second threshold, then utilizing a second compensation value for said compensation value for the plurality of light emitting elements;
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.
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Citations
25 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; comparing the first value against a first threshold to identify a compensation value for aging of said each element; comparing the first value against a second threshold if the first value exceeds the first threshold; if the first value is between said first and said second thresholds, then utilizing a first compensation value for said compensation value for the plurality of light emitting elements; if the first value exceeds the second threshold, then utilizing a second compensation value for said compensation value for the plurality of light emitting elements; 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, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. 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 diode 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 diode; a first module operating characteristics of said light emitting diode to identify a compensation element to compensate for aging of said light emitting diode, by comparing a first value corresponding to activation data the light emitting diode against a first threshold; comparing the first value against a second threshold if the first value exceeds the first threshold; if the first value is between said first and said second thresholds, then utilizing a first element for said compensation element; and if the first value exceeds the second threshold, then utilizing a second element for said compensation element; a second module to adjust an intensity of an output of said light emitting diode to compensate for said white colour point drift by adjusting an intensity of activation of said light emitting diode 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 (16, 17, 18, 19, 20, 21, 22)
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23. 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 first value corresponding to one of;
the total time the plurality of light emitting elements has been activated; and
a function of activation time and an intensity value of the plurality of light emitting elements;comparing the first value against a first threshold to identify a compensation value for aging of the plurality of light emitting elements; comparing the first value a second threshold if the first value exceeds the first threshold; if the first value is between said first and said second thresholds, then utilizing a first compensation value for said compensation value for the plurality of light emitting elements; if the first value exceeds the second threshold, then utilizing a second compensation value for said compensation value for the plurality of light emitting elements; 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. - View Dependent Claims (24, 25)
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Specification