Distribution Design Of LED Backlight For LCD

Liquid crystal display (LCD) is the mainstream status of the present flat display, and ithas low power consumption, light weight and thin thickness advantage. Because Liquidcrystal display itself can’t shine, it just display purpose by depending the modulation externallight. Back light is a light source which located behind in the liquid crystal display. With thedifferent of the former generation backlight-CCFL, LED has such outstanding advantages aswide color gamut, high brightness, high dynamic range. Therefore LED backlight necessarilywill be the next generation of liquid crystal display light source instead of CCFL backlight,and the related research has become the focus of international display industry competition.As a new green light source, LED has a completely different luminescent mechanism andstructure with CCFL light source. This paper makes light design of LED back light with twokinds of common structure. And it studies the influence for back light module opticalperformance that each key parameters in design of light distribution. Through the simulationof the simplified model, this paper gets the key parameter value for the optimal design.The chapter one of this paper firstly introduces development course and current situationof the LCD industry. And then it introduces development present situation and trend of ourcountry’s liquid crystal display industry.The chapter two of this paper firstly introduces respectively LED light source, diffusionbarrier, prism film, reflective film of direct the type LED back light module. Then itintroduces the light guide plate which is a very important optical element in side the type LEDback light module, separately from the classification of light guide, production methods andbasic working principleThe chapter three of paper firstly conduct optical estimation based on the size of thedirect the type LED back light module for, and get the number of LED light source andexpected uniformity. Then through simulated and analyzed the LED light source array, thispart analysis optical performance influence of LED light source array to back light module.Then this paper design a second lightguide-diffusive component applied to direct the type LED back light module. Effects of incident surface, exit surface, height and thickness ofsecondary lightguide-diffusive component on optical performance of direct type LED BLMwere studied theoretically. According to the deficiency of the initial simulation results, withthe improvement of micro reflection structure on the PCB substrate of direct the type LEDback light module, this paper get the better optical display effect, and analysis related causesof the back light module optical performance. Finally uniformity of the back light moduleincreases to88.17%, which conform to optical performance requirements of the back lightmodule.The chapter four of this paper firstly introduces light guide network theory calculationof side the type LED back light module. Then the model of light guide plate and LED lightsource were designed by the optical simulation software TracePro. Combined with seventeenvalue method, it analysis the influence on light energy utilization ratio and uniformity of thelight guide by no-network structure, uniform network structure, nonuniform network structure.From the analysis result, it is true that the uniformity of the light guide can have greaterascension when light guide is distribution of the non-uniform network structure. Finally usingseparate region non-uniform network design, uniformity of the back light module increases to81.4%, and the light energy utilization ratio increases to39.87%, which provide a certaindesign ideas for light guide design of the side the type LED back light module.Finally, the chapter five of this paper summarizes this research, and points out the nextfurther research direction for deep research.