Design And Fabrication Of Mini LED Chips And Displays

Light Emitting Diode(LED)have the characteristics of high luminous efficiency,low power consumption,and short response time,and are widely used in the field of lighting.When the size of the LED is reduced to the micron level,a better display effect can be achieved by combining the driving circuit in the display field.Compared with the current mainstream traditional liquid crystal display and organic light emitting diode display(OLED),Mini LED display technology has huge advantages,whether in direct display or as a backlight source for liquid crystal display,and can be used in computers,tablets,TVs and other consumer products.Widely used in the field of electronics.Mini LED display technology is considered to be the mainstream development direction in the future.This paper firstly introduces the development history and characteristics of light-emitting diodes,and summarizes the widely used display technologies.Blue light miniature light-emitting diodes(Mini LEDs)with a size of 250×120μm were designed and fabricated using patterned sapphire epitaxial wafers,and their optoelectronic properties were characterized.The 0201 type light-emitting diode was used as the display pixel to design and manufacture the Mini LED display,and its performance was tested and explored.The main contents are as follows:Based on semiconductor technology,layout design and process design of micro-miniature light-emitting diodes are carried out,and blue-light patterned sapphire epitaxial substrate is used for fabrication.The morphology and optoelectronic properties were characterized.The Mini LED turn-on voltage is 2.48 V.At 3 m A,the main wavelength of the Mini LED is 471.05 nm,the peak wavelength is467.94 nm,the full width at half maximum is 19.5nm,and the color coordinates are(0.1369,0.0547).When the current density is 2.53 A/cm~2,the external quantum efficiency value of the bare-die Mini LED is 32.36%.When the current density is 3.1A/cm~2,the bare-chip Mini LED lumen efficiency is 21.22 lm/W,and it can radiate0.69 m W optical power.To design the RGB Mini LED display,firstly select the design idea,carry out the parameter design,and select the appropriate driver IC and components.The optoelectronic properties of 0201 light-emitting diodes are characterized and analyzed,which are suitable for Mini LED display.Design the schematic diagram of the components used,draw the corresponding package,establish a package layout library,and use Altium Designer17 to design the PCB board.Finally,the PCB board making process design and the SMT patch process design are carried out to complete the production of the display substrate.The final designed and produced PCB substrate is a double-layer board,the size of the PCB board is 363 mm×205 mm,the diagonal size of the display area is 14.1 inches,the pixels are 96×64,the aspect ratio is 16:9(H:V),and the pixels The pitch is 3.25 mm(H)×2.74 mm(V),the PM drive mode is adopted,the scanning mode is common cathode static scanning,and the number of partitions is 6144.Self-built debugging platform,carried out image detection and analysis on RGB Mini LED display substrate,achieved local dimmimg effect,carried out defect exploration on bad pixels,tested the brightness and brightness uniformity of red,green and blue samples,and obtained red light samples The average brightness is423.22 cd/m~2,and the brightness uniformity is 99.58%;the average brightness of the green sample is 1723.11 cd/m~2,and the brightness uniformity is 99.94%;the average brightness of the blue sample is 658.11 cd/m~2,and the brightness uniformity is99.68%.The spectra of the three samples under different grayscales were tested and the FWHM values were obtained.The wavelength consistency was good and the color deviation was small.The blue light sample was explored as a backlight source.After adding quantum dot film,the average brightness was 1096.11 cd/m~2,an increase of 66.55%.The brightness uniformity is increased by 0.24%;after adding a brightness enhancement film,the average brightness is 2060.78 cd/m~2,and the brightness is increased by 88%.Brightness uniformity improved by 0.04%.