LCD Inspection: Color, relative intensity, spectroscopy and film thickness of pixels and light sources.
LCD displays consist of a series of colored lighted areas arranged in a pattern and can only be readily viewed with magnifying optics. They are used as high resolution displays for everything from mobile phones to video displays to MP3 players. There are many different designs but their small scale features cause many quality control challenges.
Due to the nature of LCD displays, they are manufactured with hundreds of rows of microscopic "pixels" on a surface. These pixels can be smaller than 50 microns across. Quality control of both the components and completed LCD displays is done by optical microspectroscopy. Microspectrometers, such as those made by CRAIC Technologies, are used to measure the color and the intensity of the output from individual pixels and from groups of pixels. In fact, CRAIC microspectrometers can be used to map the color and intensity outputs of individual pixels in addition to the entire LCD display including the light source. This is important as manufacturers of LCD displays need to make sure that all the different types of pixels and light sources are the same color and brightness. A microspectrophotometer does this quickly and easily.
To learn more about LCD display testing: