Lcd Monitor Response Time Measurement Method And System

The Liquid-Crystal Device (LCD) was widely applied to industry and daily life. As an important parameter of LCD, the response time reflected the display quality of moving image on the LCD. So it was necessary to research the measurement method and system for the response time of LCD. With the launch of Methods of measurement for digital television flat panel displays constituted by Ministry of Information Industry and TCO'06 Media Display, there were explicit requirements to the standard for the measurement of black-white response time, especially for measurement of the grey to grey response time of LCD. By far there were no perfect solutions and systems for the measurement of response time. So it is fain to introduce the professional measurement instruments from aboard.Based on the Methods of measurement for digital television flat panel displays and TCO'06 Media Display, this article committed itself to develop a measurement instrument for the black-white response time and grey to grey response time of LCD with high precision, strong anti-jamming, and low cost, to meet the need of LCD manufacturers and detection agencies.According to the display principle of LCD and the measurement requirement of response time, a general scheme was proposed with the combination of computer software technology and singlechip controlling theory. Whereafter, the engineering design and testing experiments were described in details of optical system, signal collection system and software system. In the signal collection system, in order to measure the grey to grey response time, the difference electrical level controlling circuit and voltage gain controlling circuit were introduced to choose different reference level and gain multiple according to the different luminance grey scales electrical level. In the software system, the singlechip worked as the lower computer, and the industrial computer worked as upper computer. The upper computer communicated with lower computer through RS-232 serial interface. The lower computer programs took charge of controlling the reference level of the difference circuit and gain multiple of the voltage amplifier, setting the sample interval and controlling luminance sampling, data storage and transfer. The upper computer programs took charge of controlling the lowercomputer, generating the measurement signal, measurement parameters input, data analysis and processing, and measurement results output.After the design and function debugging, a series of factual experiments were carried out to measure the response time of LCD with the system. The experimental results showed that the repeatability error of the system met the requirements of Methods of measurement for digital television flat panel displays and TCO'06, and the measurement results were consistent with the results obtained by oscillograph. So this measurement system was characteristic of high repeatability and accuracy. Finally, the technical aspects of this article were summarized, and then the existing deficiencies and the possible improvements of this system were prospected.