title: Modified point spread function for efficient high dynamic range LED backlight capable of high uniformity, high contrast, and smooth gradients.
abstract: We investigate the effect of new point spread functions (PSFs) on the uniformity and contrast of high dynamic range displays that use local dimming of LEDs to yield a large dynamic range. A PSF shaped like a quadratic B-spline was hypothesized to create a uniform brightness backlight, as well as producing linear and quadratic gradients, while maintaining a very high contrast. We have found a practical optical structure to produce such a PSF, yielding a nonuniformity of only ±0.8%, while enabling a contrast ratio of 5∶1 and 33∶1 over distances of one and two unit cell spacings, respectively.
authors: Jakob
authors: J
authors: Emmel
authors: Lorne A
authors: LA
authors: Whitehead