In tribology, a contact condition between mating surfaces is very important to reduce friction and raise their lifetime.Direct observation of apparent contact area is necessary for a better understanding of the contact condition. However, it takes a lot of measurement time to observe the whole apparent contact area with the existing contact microscope. Thus, another technique is required for a faster method to observe the real contact area. So, the laser microscope with a wide field of view we developed has been used to observe the whole apparent contact area for a very short time. A rubber disk specimen of a diameter of 5mm was pressed on a glass plate at several different loads and their contact areas were observed through the glass plate. The same contact areas were observed with the contact microscope. Both the measured results by two different methods were compared with each other. It was found that they were similar with each other. Considerably wide apparent contact area between a platen rubber roller and the glass plate was observed with the laser microscope with a wide field of view. The distribution of real contact ratios and micro-slips on the contact area were obtained. A Relationship between the real contact ratios and the micro-slips on the contact area was discussed.

In tribology, a contact condition between mating surfaces is very important to reduce friction and raise their lifetime. Direct observation of apparent contact area is necessary for a better understanding of the contact condition. We examined the distribution of real contact area between a platen rubber roller and a glass plate using a laser microscope with wide field of view. Based on these observations, the distribution of real contact area ratio, which is the ratio of real contact area to the apparent contact area at each point, was calculated. Micro-slips over the whole apparent contact area were measured with several torques applied to the platen roller. The relationship between real contact area ratio and micro-slips on the contact area are discussed.