Research And Design Of Reflective And Backlight Device Are Based On LED Light Source

Solid state lighting brings giant changes to the traditional lighting. Especially, the applications of LED or LD, as a new light source, of course lead to the new designing of the optical system for adapting to the difference occurred in light source. LEDs have recently been applied to screen backlight and cars headlight except for the commercial lighting, and tri-color LD has even been used for the modern car headlight. The reasons of adopting LED or LD lie in the advantages of LEDs as Hg-free, long-life, energy saving, good efficiency of light and stability. This work aimed to the applications of LED or LD into screen backlight and cars headlights and attempted to develop or design new type of reflector, light homogeneous unit and light guide.At First, the background of the use of LEDs or LDs in cars headlights was introduced and we analyzed the future trend of this technological solution. Not only the optical system designing but also the overall headlight production for light motorcycle still kept a level so far from the industrial standard and technological requirements. Meanwhile there doesn’t exist the very industrially technological standard for the light motorcycle at present. We therefore attempted to develop and design a new type of headlight for the light motorcycle relying on the LED as light source and checked its quality and consistency to the available GB19152-2003 (Photometric characteristics of moped headlamps). By considering the structure and optical tissues of LEDs, far differing from the traditional light sources, our attentions were mainly focused onto the design of reflector for better controlling the emitted light and higher efficiency of light usage. The model of optical reflector was established based on the theory of the edge beam in non-imaging optical system in combination with the reverse light beam tracking form target illuminated surface, and then numerical calculations was carried out in the Matlab station to obtain the photometrical critical point of the reflector. According to the critical point, the surface parameters and reflector model was squinty built under the environment of three-dimensional mechanical design software. The simulated results from the software of Tracepro indicated that the designed reflector was capable of satisfying both high beam and dipped beam requirements, and of transferring up to 97% light intensity.LED flat lamp based on the development of LED backlight is another commercial application of LED lighting. The characteristics of the LED flat lamp is high luminous efficiency, energy saving, no glare, uniform light, strong plasticity, and so on, which is more advantages in building a harmonious light environment. The second part of this paper tries to design ultra-thin flat lamp with a narrow margin structure and tunable color temperature.A new type of diagonal light coupling mode has been designed, whose LED light obliquely placed on the rear of a light guide plate placed on or embedded in the light guide. Basing on 4500 K of the white light LED, compensating the white light by control the brightness of red/Green/blue light which realized by modulation the circuit, get a significantly lighting groups with tunable color temperature. Achieving a continuous changing light source with high color index and width color temperature changes. Compared with the straight down type and the side back light mode, the oblique strip type backlight design are reducing the LED quantity, energy consumption, and the heat input.