DE2046851

1,264,778. Measuring transmissivity photoelectrically. BUCKBEE MEARS CO. Aug.26, 1970 [Jan.15, 1970], No.40967/70. Heading G1A. In an apparatus for measuring the transmissivity of different surface portions of an object 14 having a curved surface, e.g. a TV tube face or a foraminous shadow mask for producing such a face, the object is rotatably mounted on a table 24 and a radiation source 36 and photo-cell 40 are rigidly attached to a pivot arm 32 pivotable about a pin 30, thus enabling the transmissivity of portions of the object to be measured in a direction normal to the surface. To obtain most accurate results, the distance from the surface of the mask to the pivot axis corresponds to the mask radius of curvature.