In this automatic spacers counting system the lamp emitting light energy was focused through the LCD plate onto the microscope and CCD camera. The system consists of a CCD camera, which scans the particle patterns from a microscope set. The CCD camera is connected to a frame grabber. The frame grabber digitize video signals from the CCD camera in real time and store the digitalized image into the on-board frame memory. The image can also be displayed simultaneously on an analog video monitor. We can thus use this interface to process the analog image signal.

The experiments are carried out on a PC-based machine using a self-developed computer program. We will present the result in three different image samples. There are four sizes of spacers used in the TFTLCD facility: 6 ƒÝm, 6.75ƒÝm, 8.25ƒÝm, and 9ƒÝm. The precision plastic spheres ranging from 3 to 4 microns in diameter are particularly useful as spacers where soft substrates are used. Nine parts of a LCD plate should however be inspected the conjoint of over three grains of spacers will be unacceptable in the LCD manufacturing.

We find that each kinds of LCD plate is processed well. Obviously, the spacers of each different image sample are detected. Fig.14 shows our results of the test image samples. These samples (Fig14.(a).(c).(e)) are captured from the LCD production line. In the original image (Fig.14 (a).(c).(e)), a 1mm¡Ñ1mm square frame is usually the size of the ROI (region of interest) in which the spacers counting process must perform. Fig.14 (b).(d).(f) shows the result. In the mean time we can accomplish many static works to realize the quantity and distribution of the spacers in the different situations of the LCD plate. It's worth noting that we can see that conjoint spacers are detected in a different background.