Multi-primary backlight for multi-functional active-matrix liquid crystal displays
View Patent ↗A direct view display provides a light modulating panel and a backlight including first and second sets of spectral emitters. Several modes of operation may be provided including an advanced 2D mode, and an enhanced color gamut mode employing simultaneous illumination of the first and second set of spectral emitters. Another embodiment may be an optical structure for a multi-functional LCD display with wide color gamut and high stereo contrast. The optical structure may also be used to produce more saturated colors for a wider display color gamut and also may be used to produce a brighter backlight structure through light recycling of the wider bandwidth light back into the optical structure.
1. An optical structure for providing light to a display, comprising:
an excitation source operable to transmit illumination;
an input filter operable to receive illumination from the excitation source and operable to substantially transmit a first wavelength band of light and substantially reflect a second wavelength band of light;
an emitter region with emitters, wherein the emitter region is operable to receive at least the first wavelength band light, and the emitters are operable to be excited by at least the first wavelength band of light and emit a third wavelength band of light; and
an output filter operable to receive at least the third wavelength band of light from the emitter region, and operable to output at least a fourth wavelength band of light in which the bandwidth of the fourth wavelength band of light is narrower than the bandwidth of the third wavelength band of light, wherein the display receives addressing for a stereoscopic image, and a first light guide plate and a second light guide plate are scrolled so that a left image and a right image are illuminated by spectrally separated sources.
2. The optical structure for providing light to a display of claim 1 , wherein the input filter comprises a dichroic filter and the output filter comprises a dichroic filter.
3. The optical structure for providing light to a display of claim 1 , further comprising a cavity surrounding at least the input filter, the emitter region and the output filter, wherein the cavity is operable to receive illumination from the excitation source.
4. The optical structure for providing light to a display of claim 3 , wherein the cavity further comprises at least one of white or metallized internal walls.
5. The optical structure for providing light to a display of claim 1 , further comprising an angle reducing element operable to receive illumination from the emitter region.
6. The optical structure for providing light to a display of claim 5 , wherein the angle reducing element further comprises prismatic tape.
7. The optical structure for providing light to a display of claim 1 , further comprising an angle transforming non imaging optic operable to receive illumination from at least the excitation source.
8. The optical structure for providing light to a display of claim 7 , wherein the angle transforming non imaging optic is one of a light pipe or compound parabolic concentrator.
9. The optical structure for providing light to a display of claim 1 , further comprising an angle increasing element operable to receive light from the output filter.
10. The optical structure for providing light to a display of claim 1 , further comprising an optical spacer located between the output filter and at least a first light guide plate.
11. The optical structure for providing light to a display of claim 3 , further comprising, an integrator located between the excitation source and the input filter.
12. The optical structure for providing light to a display of claim 1 , wherein the emitters are tuned to emit light at a wavelength longer than the light received from the input filter.
13. A method for backlighting a display, comprising:
providing at least a first wavelength band of light from an illumination source;
receiving the first wavelength band of light at an input filter and transmitting the first wavelength band of light through the input filter;
receiving the first wavelength band of light at an emitter region and exciting emitters in the emitter region, thereby producing at least a second wavelength band of light, and transmitting at least some of the first wavelength band of light through the emitter region;
receiving the at least second wavelength band of light at an output filter and outputting a third wavelength band of light in which the bandwidth of the third wavelength of light is narrower than the bandwidth of the at least second wavelength of light; and
receiving at least some of the first wavelength band of light from the emitter region at an output filter and transmitting a fourth wavelength band of light, wherein the bandwidth of the fourth wavelength band of light is narrower than the first wavelength band of light from the with emitter region, wherein the display receives addressing for a stereoscopic image, and a first light guide plate and a second light guide plate are scrolled so that a left image and a right image are illuminated by spectrally separated sources.
14. The method for backlighting a display of claim 13 , further comprising receiving a third wavelength band of light at the input filter produced by the emitter region.
15. The method for backlighting a display of claim 13 , further comprising directing wavelengths of light outside of the bandwidth of the third wavelength band of light back towards the emitter region.
16. The method for backlighting a display of claim 15 , wherein receiving the wavelengths of light outside of the bandwidth of the third wavelength band of light at the emitter region further comprises exciting emitters in the emitter region and producing light within the bandwidth of the third wavelength of light.
17. The method for backlighting a display of claim 14 , further comprising directing the third wavelength band of light back towards the output filter.
18. The method of backlighting a display of claim 13 , further comprising scrolling the light guide plates so that a first image and a second image on the display are illuminated by spectrally separated sources.