Research On Ultra-Thin Of Direct-Lit LED Liquid Crystal Display Backlight Module

In some areas,large-size liquid crystal displays still have irreplaceable advantages.In large-size liquid crystal displays,liquid crystal displays using direct-down backlight technology have advantages in brightness,contrast,uniformity,and color expression.But at the same time,there is an obvious technical defect: because there is no light guide plate in the direct-down backlight module,a mixed light height of a certain distance is required,resulting in an excessive thickness.Therefore,it is of great practical significance to realize the ultra-thin of the direct-down backlight module.This paper introduces the development history of backlight module,the advantages of LED backlight,and expounds the current research status and main design schemes.Then a lensless ultra-thin scheme is proposed,in the backlight module,the thickness of the backlight module is reduced by using truncated cone,cone and regular hexagonal unit.Through comparative analysis and theoretical calculation,the specific size of the truncated cone is obtained,and the appropriate LED light source is selected,and then the 3D modeling is carried out.And the simulation of the effect on uniformity of different arrangement pitch,mixed light height,and cone size is performed on TracePro.Finally,the uniformity reached 94.27% at a mixed light height of 16 mm.The simulation results are significantly better than the indicators in thenational standard.And experimental data shows that the arrangement pitch and cone size have a greater impact on uniformity.Since the thickness of the backlight module is reduced,it is not conducive to heat dissipation;the LEDs in the backlight module are very sensitive to operating temperatures.Once the operating temperature exceeds the acceptable range,the optical performance of the LED will drop rapidly.Therefore,in this paper,two kinds of heat dissipation methods are designed: heat dissipation truncated cone and thermal conductive silicone film.By means of heat convection and heat conduction,the heat can be transferred to the external environment in time and quickly,which ensures the normal operation of the LED.