Reflectors with spatially varying reflectance/absorption gradients for color and luminance compensation
A Point Spread Function (PSF) of a light source is controlled by the provision of a PSF modifier on a reflector at or near the light source. The modifier may be a gradient or spatially varying application of any of transmission holes, filters, and absorptive dots. The invention may be applied to displays (e.g., backlighting of displays), and arrangement of the modifiers may include patterns that vary according to artifacts occurring in the display. The PSF modifier may flatten, remove, or increase tails, or mitigate fringing colors or patterns. In backlight arrays, the PSF modifier may be similar for all centrally located light sources, and exhibit differences when applied to light sources near edges or other anomalies in the backlight or surrounding structure.
1. A display, comprising:
a spatial modulator; and
a backlight comprising at least one LED with a reflector configured to reflect light emitted by the LED towards the spatial modulator;
wherein the reflector comprises sidewalls with transmission holes, and
wherein the transmission holes are configured to capture some of the light emitted from the LED and thereby alter a Point Spread Function (PSF) of the LED illuminating the spatial modulator, where Point Spread Function (PSF) is a form or shape of light.
2. The display according to claim 1 , wherein the transmission holes are positioned so as to surround the LED.
3. The display according to claim 1 , wherein the transmission holes are of varying sizes.
4. The display according to claim 1 , wherein the transmission holes are relatively smaller closer to the LED, and relatively larger further out on the reflector.
5. The display according to claim 1 , wherein the transmission holes are relatively larger closer to the LED, and relatively smaller further out on the reflector.
6. The display according to claim 1 , wherein the transmission holes are arranged in a pattern that is spatially varying and/or non-symmetrical near edges or corners of the backlight.
7. The display according to claim 1 , wherein the reflector further comprises at least one of light absorptive dots and reflective dots.
8. An LED reflector, comprising:
a base that is configured for carrying an LED;
a plurality of sidewalls that are arranged surrounding the base, and, when the base carries an LED, configured to reflect light emitted from the LED in a generally uniform direction towards an intended target; and
a gradient pattern of transmission holes in the sidewalls, configured such that light entering the transmission holes is removed from a Point Spread Function (PSF) of the light that is emitted by the LED for illuminating the intended target, where Point Spread Function (PSF) is a form or shape of light.
9. The LED reflector according to claim 8 , wherein the gradient pattern comprises transmission holes that are relatively smaller closer to the base, and are relatively larger further out on the reflector.
10. The LED reflector according to claim 8 , wherein the gradient pattern comprises transmission holes that are relatively larger closer to the base, and are relatively smaller further out on the reflector.
11. The LED reflector according to claim 8 , wherein at least one of the size, shape, gradient, spatial pattern, density, and geometric parameters of the transmission holes is adapted to modify the illumination of the intended target.
12. The LED reflector according to claim 8 , wherein an angle between the base and the sidewalls is adapted to modify the illumination of the intended target.
13. The LED reflector according to claim 8 , wherein the transmission holes are spatially varying.
14. The LED reflector according to claim 8 , further comprising at least one of light absorptive dots and reflective dots.
15. A backlight comprising an array of LEDs each comprising an LED reflector according to claim 8 .
16. The backlight according to claim 15 , wherein the transmission holes of the LED reflectors are arranged such that the backlight uniformly illuminates the intended target.