An Optomechatronics Inspection Technique of TFT Array Flaw Applied to Medical Display

For medical display, the pixels on array panels are getting smaller. Therefore, flaw detection and measurement are getting more difficult and critical for managing yield and quality in a thin-film-transistor (TFT) array process. The TFT array testing technique has been used for flaw detection and process yield control. As the TFT array pixel size is getting smaller and the resolution is getting higher, both of them have encountered a performance limitation in detecting the critical small-pixel defect for the ultrahigh-resolution TFT array such as medical display applications. In this study, a novel approach for flaw detection is proposed. The proposed optomechatronics technique with interdigitized shorting bar design configuration is used for inspection. The experimental results show that, by using the voltage imaging technique, the flaw detection rate for small-pixel size, high-resolution TFT array has been effectively improved from 50% to 80%. The detected subpixel size for a TFT array panel can be smaller than 53 μm for a 30-inch ultrahigh-definition medical display application.