Review Paper: Diffractive backlight technologies for mobile applications

Abstract

Liquid-crystal-display backlight units have developed in their conventional configuration into very efficient and uniform components that allow the display to present a high-quality image to the user. Developing the backlight unit itself further faces a challenge of diminishing returns to the investment in innovation. A system-level redesign is required for the entire display module, and diffractive alternatives to the backlight design can allow a more-energy-efficient design for the display. This review concentrates on small-to-medium displays because diffractive backlight studies have also centered in this class of displays. The state of the art of backlight design is summarized and the motivation for energy-efficient system design is outlined. The theoretical basis of diffractive backlights is given, and key research studies in the area of diffractive backlights are reviewed. Finally, a discussion on the performance and future outlook of diffractive backlights completes the paper.

Design and fabrication of submicron period grating as an imprinted light guide plate for a backlight unit

“…Based on the waveguide optics, the incident angle range of the incoming light to the grating is determined by the critical angle of refraction, as described in equation (2). The material of the polymeric LGP usually consists of polymethyl methacrylate (PMMA, n = 1.492), polycarbonate (PC, n = 1.580), or other transparent polymer or a glass substrate whose refractive index is approximately 1.5 [21].…”

Light Recycling Using Perovskite Solar Cells in a Half‐Cylinder Photonic Plate for an Energy Efficient Broadband Polarized Light Emission

“…A significant fraction of the world current energy consumption goes into illumination sources or devices that incorporate an illumination source in them. [1,2] To enable a reduction in the use of fossil fuels, an optimization of the efficiency in such illumination devices may become as relevant as the use of renewable energies to power them up. Note that, in some of the electronic devices incorporating a liquid crystal display (LCD) more than 90% of the light emitted by the illumination source may end up being lost.…”

Design of Low-Glared LED Rear Light of Automotive for EU ECE Regulation by Use of Optimized Micro-Prisms Array

“…In order to solve the above problems, several new design ideas for car signal lights have been proposed [6][7][8][9]. For example, the indirect light installed with a micro-prism sheet and LED [1][2][3][4][5][6], which is more promising and has been used to construct an automotive rear light with an attractive pattern, as shown in Figure 1b, not only providing a smooth lighting surface, flexibility of shape, but also reducing the amount of LEDs used [10][11][12][13]. Using the technology of micro-prisms films covering the surface of the signal light changed the direction of the output light to provide a more uniform illumination surface and high efficiency.…”