Study On Measurement Method Of LCD Display Performance In High Temperature Environment

With the advantages of small size,low energy consumption,high display quality,less radiation,and good anti-interference,liquid crystal display(LCD)has become the mainstream technology of flat panel display.However the working environment becomes more and more harsher when used in various applications.In order to work well in high temperature environment,LCDs should be tested objectively and comprehensively.In this paper,the test method of LCD performance under high temperature environment is studied and the test system is built.Test system errors are analyzed and the measurement errors are corrected.The experimental scheme is proposed to test the optical performance of a LCD in high temperature environment,including luminance,luminous uniformity,contrast and viewing angle of a LCD.In this paper,the polarization characteristics of a LCD at high temperature are tested and the measurement results are modified,which can get the color changes of a white field when the LCD works in high temperature environment.The test method proposed in this paper is applied to test the optical performances of two LCDs from different manufacturers in high temperature environment,which can help to choose a suitable LCD to improve the reliability.The paper analyzes the various display defects of a LCD at high temperature.The brightness map measured by an imaging device UMaster is firstly converted to a grayscale image.Based on characteristic of human sight,the appropriate threshold value is decided to convert the grayscale image to a binary one.The defective portion is extracted and with the help of image morphology the defective region is connected and classified according to the characteristics of the defect.The display defect detection interface of a LCD at high temperature is realized by MATLAB.By using the test method proposed in this paper,the objective data of display performance of a liquid crystal display can be obtained.The detection algorithm designed in this paper can effectively detect the display defects of a liquid crystal display at high temperature.