US 8,575,865 B2 · Temperature based white point control in backlights

Abstract

Systems, methods, and devices are provided for maintaining a target white point on a light emitting diode based backlight. In one embodiment, the backlight may include two or more strings of light emitting diodes, each driven at a respective driving strength. Each string may include light emitting diodes from a different color bin, and the respective driving strengths may be adjusted, for example, through pulse width modulation or amplitude modulation, to maintain the target white point. In certain embodiments, the driving strengths may be adjusted to compensate for shifts in the white point that may occur due to temperature or aging. A controller may adjust the driving strengths based on feedback from a temperature sensor, from an optical sensor, from a user input, or from calibration data included within the backlight or system.

Claims23

Dependent claims

A display, comprising:

a plurality of white light emitting diodes arranged within an electronics region and other regions of a backlight to produce an emitted white point that corresponds to a target white point, wherein the electronics region is configured to produce more heat during operation of the display than the other regions;
a plurality of color compensating light emitting diodes arranged only within the electronics region of the backlight and intermixed with the plurality of white light emitting diodes;
one or more drivers configured to drive groups of one or more color compensating light emitting diodes of the plurality of color compensating light emitting diodes at a respective driving strength;
and
a controller configured to detect a temperature change within the electronics region and to adjust at least one of the respective driving strengths to compensate for a shift in the emitted white point of white light emitting diodes arranged within the electronics region due to the temperature change.

2 more elements

A method of operating a backlight of a display, the method comprising:

independently driving each of a plurality of white light emitting diode strings at a respective white point driving strength to produce an emitted white point that substantially matches a target white point, wherein each of the plurality of white light emitting diode strings is arranged within an electronics region and other regions of the backlight, and the electronics region produces more heat during operation of the display than the other regions;
driving one or more color compensating light emitting diode strings disposed only in the electronics region at a respective color compensating driving strength, wherein only the electronics region comprises color compensating light emitting diode strings;
detecting a temperature change within the electronics region of the backlight;
determining a shift in the emitted white point of each of the white light emitting diode strings arranged within the electronics region based on the detected temperature change;
and
adjusting at least one of the respective color compensating driving strengths to compensate for the shift.

3 more elements

Dependencies are inferred from the claim text.

Temperature based white point control in backlights

Life of this patent

Temperature based white point control in backlights

Life of this patent

Abstract

Claims23