Lighting Led-based Optical Parametric Testing And Applied Research

Light emitted diode (LED), as a new-type light-house after the incandescence, fluorescent lamp, and gas discharge lamp, is widely applied in the fields of information technology, illuminating engineering, and display. With the rapid growth and development of the opto-electronics, the parameters of LED should be tested strictly. Recently, many institutes have developed some high level testing devices for LED, however, those devices are costly. In this dissertation, a low cost automatic-measurement system of LED light intensity was developed according to the CIE standards. The new system can meet the test repeatability and precision. At the same time the system can reduce the costs.In this dissertation, the basic theory and measurement standards for photometric measurement of LED were introduced firstly. Then, a design for measurement system, including hardware design and software design, is described. For the system hardware, electric signals, which is converted from optical signals by the photodeterctor, is collected and processed by the 08100A-type data acquisition card. At the same time, the PC controls the MCU to drive the step-motor in order to complete the whole measurement process. The system software, which is composed of the stepper motor-driven programming, A/D conversion process design, and data communication, is based on the platform of LabVIEW. The system software controls the step-motor, and gathers and processes the signals.Further, after measuring the typical LED samples and analyzing the measured data by Matlab mathematical tools,1 w-class "piranha" white LED luminous intensity with the mathematical expression, and f(x)=a*x-2, under the conditions of CIE standard and the axial propagation, respectively, were obtained. On this basis, a LED lamp was designed using TracePro software.Additionally, for the topic issues about the efficiency of white LED luminous, the limit luminous flux efficiencies (long-term luminous efficiency) of the white LED, combining blue LED chip and YAG:Ce yellow phosphor, and RGB producing white LED are calculated to be 200.0 and 464.3 lm/w, respectively.Finally, on the base of the works in this dissertation, the possible imporvements in this measurement system are proposed.It can be expected, the subject of our research will provide relevant information for the LED optical design and related areas.