Backlight Panel Research Articles

Three-dimensional imaging system based on a light-emitting diode array

A two-dimensional light-emitting diode array is used to replace the viewing-zone-forming optics in-multiview full-parallax three-dimensional image display systems. Since the array is not working merely as the viewing-zone-forming optics but also as the backlight panel for the liquid-crystal display (LCD) panel, it allows constructing three-dimensional imaging systems having the same structure as the current LCD display. The designed system displays images with good depth sense.

Physical‐based photon mapping for an LED backlight lighting simulator

Abstract— Liquid‐crystal displays (LCDs) have become increasingly popular due to their lower price and larger sizes. In particular, backlights having an RGB LED source have recently attracted attention, because they have a wider color gamut, higher luminance, and lower power consumption. However, even when the backlight area is uniformly covered with light modules based on arrays of individual LEDs, this does not ensure a uniform chromaticity and luminance over the backlight panel, thereby stressing the need for lighting simulation of the backlight. Accordingly, this paper proposes an effective lighting simulator to predict the chromaticity and luminance distribution of an LED backlight panel for an LCD. First, the spectrum‐based photons are all initially generated using a random function with a constraint satisfying the spectral power distribution of the actual LED light sources, while their emitting directions are determined based on a pre‐calculated probability using a random variable angle. The optical characteristics of the inner sheets in the LCD backlight structure are then modeled using the wavelength and incident angle to predict the next direction of each photon based on the reflection and transmittance at an intersection. All the photons that reach the unit area of the outward panel are gathered to shape their spectral power distribution, then converted to CIEXYZ values and multiplied with a color‐matching function. Finally, a realistic image visualization of these CIEXYZ values is achieved through standardized device characterization using the sRGB mode. Experiments confirm that the proposed spectrum‐based photon mapping can effectively predict the chromaticity and luminance distribution of an LED backlight panel, providing a good lighting simulation of an LED backlight before manufacturing the LCD.

Fabrication of a novel integrated light guiding plate by microelectromechanical systems technique for backlight system

A backlight panel (BLP) with a cold cathode fluorescent lamp (CCFL) light source, which is referred to as the backlight unit (BLU) is considered in the light module of a thin film transistor (TFT) LCD. A typical BLP is comprised of a light-guiding plate (LGP) and some optical components, such as reflective sheets, diffusive sheets, and prism sheets. We propose an integrated LGP that combines three functions of optical components by using microelectromechanical systems (MEMS) and hot-embossing techniques. The microprism structure, the micropyramid structure, and an aluminum thin film are used for the integrated LGP not only to eliminate the five optical components, but also to save the space and the cost of the BLU. From experimental illumination results, the maximum illumination is 426.1 lux and the minimum illumination is 370.4 lux. Thus, the integrated LGP achieves a uniformity of illumination of 86.9%. The new BLU could be simplified as only one integrated LGP and only one white LED light source without using any optical components. We anticipate that the integrated LGP could make the displays thinner and brighter for thin LCD application.

32.3: An Eyeglass‐Free Rear‐Cross‐Lenticular 3‐D Display

AbstractWe have developed a new method of an eyeglass‐free stereoscopic display, which we call “Rear‐Cross‐Lenticular 3‐D Display” (RCL3D). The RCL3D consists of a LCD panel, two lenticular lens sheets which run perpendicular to each other, a Checkered Pattern Mask and a backlight panel. On the LCD panel, a composite image which consists of alternately arranged horizontally striped images for right eye and left eye, is displayed. This composite image form is compatible with the field sequential stereoscopic image data. We made prototype of the RCL3D (14.5″, XGA) and confined the good quality of the stereoscopic 3‐D images. But there is slight crosstalk with the prototype. The measured crosstalk is around 5%. According to the results of a simulation of illumination profile in viewing zone, LCD with less reflectance and scattering is expected for RCL3D to reduce the crosstalk.