SURFACE PRESSURE MEASURING APPARATUS

PURPOSE:To enable the detection of parts subject to pressure accurately by a method wherein a surface pressure to be measured is received with a pressure receiving matt made of an elastic material with conical projections distributed evenly to convert a load received on each projection into an electrical signal from a light pattern. CONSTITUTION:A pressure receiving matt 12 has conical projections 15 distributed evenly with tips thereof point contacts a transparent board 13 and a light source 16 is provided at one end face of the transparent board 13. When a surface pressure P to be measured is applied on the pressure receiving matt 12, the projection 15 squeezes significantly at the part receiving the surface pressure intensely to make the contact area form a large circle. Light propagating incident on the transparent board 13 from the light source 16 forms a circular light pattern in the size corresponding to a load and reflected with a reflector 19 entering a video camera 20, with which a circular image 22 of the light pattern is formed in a square region of a unit area. The quantity of light of the light pattern is converted into an electrical signal for each pixel with the area smaller than the area of each projection and then, into a load signal.