Research On Direct-lit Backlight And Quantum Dots Color Conversion Technology Based On LED

Backlight uniformity and color diversity are two important indicators of screen evaluation,which directly affect the display performance of screen,such as resolution,contrast and color saturation of screen display.As a new generation display technology,local dimming technology is capable of controlling the brightness of direct-lit backlight module,which ensures that the screen backlight has controllable,uniform and stable output properties.With the distinct advantages of high brightness and high color saturation,the new technology,namely color conversion of quantum dots,has become a novel orientation of full-color screen display technology.However,exploring the optical characteristics and operation principle of array quantum dots are still desirable.In this dissertation,on the basis of the backlight uniformity and color diversity of screen display,LED array uniform model based on Lambert light source theory,spot replaceable array uniform model with local dimming technology and quantum dots color conversion model using Micro-LED are established and demonstrated.The presented results provide a new solution for studying the uniformity of direct-lit backlight and the color conversion procedures of quantum dots.The main work of this dissertation is as follows:1.The intensity distribution model of LED is established based on Lambertian light source theory,and the uniform conditions of LED array with two points,linear,square,circular and triangular arrangement are solved by using sparrow’s criterion.According to the uniform condition,the corresponding array parameters are obtained,and then the light field distribution of LED array is simulated.In addition,we analyze the intrinsic relations between various physical parameters that affect the uniformity of linear LED array,and then discuss and compare the uniform effect of LED array with square and triangle arrangements.Under the given conditions,when the order N of the array is greater than 11,the uniform effect of the triangle array is better than that of the square arrangement.2.Aiming at designing the direct-lit backlight with local dimming function,an array uniform model with replaceable spot is proposed and demonstrated.Firstly,the luminance distribution of a single LED spot is detected and determined as the basic elements of the sub array.Secondly,the experiment of ruler luminance detection is built to calculate the magnification coefficient between model spacing and actual spacing.The algorithm uses the method of sequentially unifying the sub area and full screen to implement the backlight module.Finally,the uniform model of the dense array is optimized,and the uniform simulation for dense array of 7×8 order of triangle and square arrangement are carried out to verify the reliability of the theoretical modality.3.Based on the color conversion principle of quantum dots film,the color conversion model of quantum dots with Micro-LED as the incident light source is constructed.By changing the viewing angle and wavelength of incident light,the spectrum,color gamut and illuminance of the emitted light using single quantum dots model are analyzed and illustrated.Under the given conditions,the power of red and green QDs excited by UV light is about 1.25 and 2 times of that excited by blue light,respectively.The arrayed model with and without microstructure are investigated and compared.By analyzing the acquired true color map and illumination map,the exporting light from arrayed quantum dots with microstructure has obvious features of clear edges and sharp color boundaries,which is extremely applicable for high-performance display devices.