Backlight having blue light emitting diodes and method of driving same
View Patent ↗An LED backlight array in which every LED, regardless of whether it is a red, green, cyan, or blue LED, contains a blue emitter. As each LED contains the same type of emitter, the backlight can be driven by a single blue driver circuit, rather than separate red, green, cyan, and blue drivers. That is, the present disclosure removes the need for red, cyan, and green driver circuits, allowing for simpler and cheaper backlights. Additionally, even though the LED backlight can contain LEDs of different colors, each has a blue emitter, and thus possesses similar aging characteristics.
1. A backlight for a display, comprising:
a backlight having a plurality of light emitters configured to collectively generate white light, the plurality of light emitters including:
a plurality of red emitters each having a blue light emitting diode (LED) and configured to emit red light;
a plurality of green emitters each having a blue LED and configured to emit green light; and
a plurality of blue emitters each having a blue LED and configured to emit blue light;
wherein each of the red emitters further comprises one of the blue LEDs, a red phosphor or nanoparticle photoconverter configured to convert blue light from the one of the blue LEDs to red light, and a casing surrounding the one of the blue LEDs and configured both to pass the red light and to block the blue light;
wherein each of the green emitters further comprises another one of the blue LEDs, a green phosphor or nanoparticle photoconverter configured to convert blue light from the another one of the blue LEDs to green light, and a casing surrounding the another one of the blue LEDs and configured both to pass the green light and to block the blue light;
wherein the red phosphor or nanoparticle photoconverter is disposed on the one of the blue LEDs, makes contact with the one of the blue LEDs, and leaves one or more sides of the one of the blue LEDs exposed, and
wherein the green phosphor or nanoparticle photoconverter is disposed on the another one of the blue LEDs, makes contact with the another one of the blue LEDs, and leaves one or more sides of the another one of the blue LEDs exposed,
wherein the casing of each red emitter is a yellow polymer casing, and
wherein the casing of each green emitter is a yellow polymer casing.
2. The backlight of claim 1 , further comprising a driver circuit in electrical communication with each emitter of the plurality of red emitters, the plurality of green emitters, and the plurality of blue emitters, wherein the driver circuit is further configured as a blue LED driver.
3. The backlight of claim 2 :
wherein the driver circuit is further configured to adjust illuminations of the plurality of light emitters according to a compensation curve relating temperatures of the plurality of light emitters to desired ones of the illuminations; and
wherein the driver circuit is further configured to adjust the illuminations of the red emitters, the green emitters, and the blue emitters according to the same compensation curve.
4. The backlight of claim 1 , wherein each LED of the plurality of LEDs is independently controllable.
5. A backlight system for a display, the backlight system comprising:
a plurality of light emitters; and
a driver circuit in electrical communication with each emitter of the plurality of light emitters;
wherein the driver circuit is configured as a blue light emitting diode (LED) driver; and
wherein the plurality of light emitters includes red emitters having blue LEDs and configured to emit red light, and green emitters having blue LEDs and configured to emit green light;
wherein each of the red emitters further comprises one of the blue LEDs, a red phosphor or nanoparticle photoconverter configured to convert blue light from the one of the blue LEDs to red light, and a casing surrounding the one of the blue LEDs and configured to pass the red light;
wherein each of the green emitters further comprises another one of the blue LEDs, a green phosphor or nanoparticle photoconverter configured to convert blue light from the another one of the blue LEDs to green light, and a casing surrounding the another one of the blue LEDs and configured both to pass the green light and to block the blue light;
wherein the red phosphor or nanoparticle photoconverter is disposed on the one of the blue LEDs, makes contact with the one of the blue LEDs, and leaves one or more sides of the one of the blue LEDs exposed, and
wherein the green phosphor or nanoparticle photoconverter is disposed on the another one of the blue LEDs, makes contact with the another one of the blue LEDs, and leaves one or more sides of the another one of the blue LEDs exposed,
wherein the casing of each red emitter is a yellow polymer casing, and
wherein the casing of each green emitter is a yellow polymer casing.
6. The backlight system of claim 5 , wherein the plurality of light emitters further includes blue emitters having blue LEDs and configured to emit blue light.
7. The backlight of claim 5 :
wherein the plurality of light emitters further includes blue emitters;
wherein the driver circuit is further configured to adjust illuminations of the plurality of light emitters according to a compensation curve relating temperatures of the plurality of light emitters to desired ones of the illuminations; and
wherein the driver circuit is further configured to adjust the illuminations of the red emitters, the green emitters, and the blue emitters according to the same compensation curve.