LED selection for white point control in backlights

A display, comprising:

• a backlight configured to operate over a temperature range;
• a first string of first light emitting diodes arranged within the backlight, wherein the first light emitting diodes have a first range of chromaticities over the temperature range;
• a second string of second light emitting diodes arranged within the backlight, wherein the second light emitting diodes have a second range of chromaticities over the temperature range;
• a third string of third light emitting diodes arranged within the backlight, wherein the third light emitting diodes have a third range of chromaticities over the temperature range, and wherein the first range of chromaticities, the second range of chromaticities, and the third range of chromaticities are set apart from one another;
• one or more drivers configured to independently drive the first string, the second string, and the third string at respective driving strengths to produce an emitted white point that corresponds to a target white point;
• and
• a controller configured to detect temperature changes within the display and to adjust ratios of the respective driving strengths to maintain correspondence to the target white point over the temperature range.

A method of operating a backlight, the method comprising:

• independently driving a first string of first light emitting diodes and a second string of second light emitting diodes at respective driving strengths to produce an emitted white point that corresponds to a target white point;
• and
• adjusting a ratio of the respective driving strengths in response to temperature changes to maintain correspondence to the target white point over an operational temperature range of the backlight;
• wherein a chromaticity difference between the first light emitting diodes and the second light emitting diodes at an equilibrium temperature of the backlight is greater than a maximum chromaticity shift of the first light emitting diodes over the operational temperature range.

A method of manufacturing a backlight, the method comprising:

• arranging a first string of first light emitting diodes within a backlight, wherein the first light emitting diodes have a first chromaticity at an equilibrium temperature of the backlight;
• arranging a second string of second light emitting diodes with respect to the first string of first light emitting diodes to produce a target white point over an operational temperature range of the backlight, wherein the second light emitting diodes have a second chromaticity at the equilibrium temperature of the backlight, and wherein the second chromaticity is separated from the first chromaticity by a chromaticity difference greater than a maximum chromaticity shift of the first light emitting diodes over the operational temperature range of the backlight;
• configuring one or more drivers configured to independently drive the first string and the second string at respective driving strengths to produce an emitted white point that corresponds to the target white point;
• and
• configuring a controller to adjust a ratio of the respective driving strengths in response to temperature changes to maintain correspondence to the target white point over the operational temperature range.