Changing from CCD to High-Resolution CMOS for Display Module Inspection
The trends in the electronic display industry are changing at a staggering pace. We see resolution increases from 720p to UHD 4k and eventually UHD 8K. There is also a vast range of display types including OLED, curved, flexible, and microdisplays. As these technologies become more popular, there is an increasing need for automated inspection that exceeds the capabilities of many 29/47MP CCD imaging sensors currently in use.
The D-65A35 camera,
the latest camera in our Diamond series, the D-65A35 camera, is the right solution for high tech display inspection challenges. This camera offers 65 megapixels of resolution and a 4:3 aspect ratio for mobile and television displays. With a 65MP resolution, there is on average, 3×3 camera pixels per display pixel. Each display pixel shown here is the subject of approximately a 9-pixel cluster of the D-65.
Example of the Diamond OLED pixel structure of a mobile phone.
The D-65 also sets itself apart from the CCD competition with its measurement uniformity. Low-frequency flat field correction helps create a uniform image while measuring a bright display by applying gain corrections for each pixel within the camera compensating for lens shading. For the measurement of dark displays, the uniformity is also increased by pixel-based offset corrections, combined with low noise very small variations of a display in dark can be measured.
Without flat-field correction vs. using flat-field correction
The throughput offered by the D-65 allows for faster inspection. This is due in part to the CMOS readout technology with the global shutter as well as a data interface that is capable of 6.5Gbit/s per CoaXpress connection. Other CCD cameras on the market with a lower resolution are capable of only a fraction of this speed.
With these features, the resulting high image quality allows for the measuring of dynamic range, linearity, and pixel uniformity in display pixels. Whether the application requires a bright inspection, dark inspection, or demura inspection the Adimec D-65 camera is capable of detecting pixel and component defects with high-speed precision and accuracy.