The Application Of Vision Technology On LED Phosphor Thickness Measurement

LED (Light Emitting Diode), it’s a solid state lighting and invented by Nick Holonyak Jrin1962. It convert electrical energy into light energy by apply voltage on PN junction. Atfirst it’s used on instrumentation state instruction light, but with the development of thetechnology LED and the continuous improvement of the luminous efficiency, today’shigh-power LED device has to achieve enough brightness as the candle level,so LED be seenas a new generation of light source after incandescent lamp fluorescent lamp. The existinghigh power white LED glow white light through mixed the blue light and yellow light whichglowed by GaN blue LED and YAG phosphor, and the thickness and uniformity of the yellowphosphor directly affect the quality of LED, so in LED the production process needs a fastand accurate testing equipment to detect the thickness of the phosphor.For this reason, this paper design a FPGA and high-speed CMOS image process system,and combination the laser triangulation technique to chieve a system for measure thethickness of the phosphor. Through the automatic test of product quality and make productionprocess to adjustment to improve the automation level of LED production process and reducedefective quantity.This paper include the system of FPGA process platform, image’s obtain and storage, theVGA display, and image algorithm of thickness measurement, they will introduced indifferent part of the paper,will include: the realization of the FPGA platform,and how toestablish a SOPC system in this platform; CMOS image acquire process and implementmethod; VGA display circuit and the realization method;the algorithm of thicknessmeasurement and realization in FPGA, through these parts to introduction System workmethod and how to measure thickness by laser triangulation.