Backlight device and color liquid crystal display
Disclosed is a backlight device which is used for a color liquid crystal display and includes a light source and a backlight housing ( 23 ). The light source includes a red light emitting diode ( 21 R), radiating red light, having a peak wavelength λpr such that 625 nm≦λpr≦685 nm, a green light emitting diode ( 21 G), radiating green light, having a peak wavelength λpg such that 505 nm≦λpg≦540 nm, and a blue light emitting diode ( 21 B), radiating blue light, having a peak wavelength λpb such that 420 nm≦λpb≦465 nm. The backlight housing mixes the red light, the green light and the blue light, radiated from the light source, to generate white light. A light emission intensity is adjusted so that a half value width of a spectrum of the red light, a half value width of a spectrum of the green light and a half value width of a spectrum of the blue light are such that 20 nm≦hwr≦25 nm, 30 nm≦hwg≦40 nm and 25 nm≦hwb≦30 nm, respectively.
1. A backlight device for illuminating with a white light, the backlight device comprising:
a transmissive color liquid crystal display panel from a back side of the backlight device, the transmissive color liquid crystal display panel including a color filter employing a red light color filter, a green light color filter, and a blue light color filter;
a light source including a plurality of red light emitting diodes for radiating red light, each red light emitting diode having a peak wavelength λpr such that 625 nm ≦λpr ≦685 nm, a plurality of green light emitting diodes for radiating green light, each green light emitting diode having a peak wavelength λpg such that 505 nm≦λpg≦540 nm, and a plurality of blue light emitting diodes for radiating blue light, each blue light emitting diode having a peak wavelength λpb such that 420 nm≦λpb≦465 nm;
a mixing means for color mixing the red light, the green light and the blue light, radiated from the light source, to generate white light;
wherein a light emission intensity of the red light, the green light and the blue light, radiated from the red light emitting diode, the green light emitting diode and the blue light emitting diode, respectively, is adjusted so that a half value width hwr of a spectrum of the red light, a half value width hwg of a spectrum of the green light and a half value width hwb of a spectrum of the blue light are such that 20 nm ≦hwr≦25 nm, 30 nm≦hwg≦40 nm and 25 nm ≦hwb ≦30 nm, respectively, wherein the half value width hwb of the spectrum of the blue light is, on average, about 5 nm wider than the half value width hwr of the spectrum of the red light, and wherein a ratio of peak intensity of the red light, the green light, and the blue light is about 0.9:0.6:1.
2. The backlight device according to claim 1 wherein a light emission intensity of the red light, the green light and the blue light, radiated from the red light emitting diode, the green light emitting diode and the blue light emitting diode, respectively, is adjusted so that a color temperature of the white light is 10000±1000 K (Kelvin).
3. The backlight device according to claim 1 wherein a plurality of red light emitting diodes, each red light emitting diode having a peak wavelength λpr such that 625 nm≦λpr≦685 nm and having different values of the peak wavelength λpr, are used as the red light emitting diode used for the light source.
4. The backlight device according to claim 1 wherein a plurality of green light emitting diodes, each green light emitting diode having a peak wavelength λpg such that 505 nm≦λpg≦540 nm and having different values of the peak wavelength λpg, are used as the green light emitting diode used for the light source.
5. The backlight device according to claim 1 wherein a plurality of blue light emitting diodes, each blue light emitting diode having a peak wavelength λpb such that 420 nm≦λpb≦465 nm and having different values of the peak wavelength λpb, are used as the blue light emitting diode used for the light source.
6. The backlight device according to claim 1 , wherein the light source radiates only three peaks of light.
7. A color liquid crystal display, comprising:
a transmissive color liquid crystal display panel having a main color filter employing three color filters for transmitting red light, green light and blue light by wavelength selection;
a backlight device for illuminating, with white light, the color liquid crystal display panel from a back side thereof, wherein the backlight device further comprises:
a light source including a plurality of red light emitting diodes for radiating red light, each red light emitting diode having a peak wavelength λpr such that 625 nm≦λpr ≦685 nm, a plurality of green light emitting diodes for radiating green light, each green light emitting diode having a peak wavelength λpg such that 505 nm ≦λpg ≦540 nm, and a plurality of blue light emitting diodes for radiating blue light, each blue light emitting diode having a peak wavelength λpb such that 420 nm≦λpb≦465 nm;
a mixing means for color mixing the red light, the green light and the blue light, radiated from the light source, to generate white light;
wherein a light emission intensity of the red light, the green light and the blue light, radiated from the red light emitting diode, the green light emitting diode and the blue light emitting diode, respectively, is adjusted so that a half value width hwr of a spectrum of the red light, a half value width hwg of a spectrum of the green light and a half value width hwb of a spectrum of the blue light are such that 20 nm≦hwr≦25 nm, 30 nm≦hwg≦40 nm and 25 nm≦hwb≦30 nm, respectively, wherein the half value width hwb of the spectrum of the blue light is, on average, about 5 nm wider than the half value width hwr of the spectrum of the red light, and wherein a ratio of peak intensity of the red light, the green light, and the blue light is about 0.9:0.6:1.
8. The color liquid crystal display according to claim 7 wherein a light emission intensity of the red light, the green light and the blue light, radiated from the red light emitting diode, the green light emitting diode and the blue light emitting diode, respectively, is adjusted so that a color temperature of the white light is 10000±1000 K (Kelvin).
9. The color liquid crystal display according to claim 7 wherein a plurality of red light emitting diodes, each red light emitting diode having a peak wavelength λpr such that 625 nm≦λpr≦685 nm and having different values of the peak wavelength λpr, are used as the red light emitting diode used for the light source.
10. The color liquid crystal display according to claim 7 wherein a plurality of green light emitting diodes, each red light emitting diode having a peak wavelength λpg such that 505 nm≦λpg≦540 nm and having different values of the peak wavelength λpg, are used as the green light emitting diode used for the light source.
11. The color liquid crystal display according to claim 7 wherein a plurality of blue light emitting diodes, each blue light emitting diode having a peak wavelength λpb such that 420 nm≦λpb≦465 nm and having different values of the peak wavelength λpb, are used as the blue light emitting diode used for the light source.
12. The backlight device according to claim 7 , wherein the light source radiates only three peaks of light.