Abstract: The present invention is a method and apparatus for mechanically bonding a polymer to a convex surface of a substrate to provide intimate contact therebetween for improved energy transport between a transducer on one side of the substrate and a chemical bath on the other. The polymer seals the surface of the substrate from the chemical bath and may have a low adhesion to the substrate. A thin film of the polymer is brought under a tensile stress to provide intimate physical contact with most of the area of the convex surface. In one embodiment, the tensile stress is achieved by providing polymer as a liquid on the convex surface and then cooling to take advantage of differential thermal contraction between the polymer and the substrate to achieve the tensile stress in the polymer.

Abstract: An indicating device in a camera indicates unambiguously whether or not the camera is loaded with film, and how much of the film has been exposed. The device is first indexed from an empty-camera position to a loaded-camera position in response to insertion of film into the camera. It is then indexed sequentially to succeeding positions, each representing the next film image area to be exposed, in response to actuation of a film transport member. The device is thus indexed ultimately to a final position signifying that no film image area remains to be exposed. It is then returned to its empty-camera position in response to removal of the film from the camera. At each of its positions the device presents an identifying indicium to a viewing site to indicate visually the corresponding camera condition. The device is especially useful in a processing camera where it indicates positively whether no film is in the camera or whether a full supply of film covered by a dark slide is in the camera.