Heat-sink imaging method and apparatus for recording surface topology

Abstract

The recording of surface topology is obtained by first bringing the surface into contact with the imaging material-coated side of a dry process dispersion type recording film comprising a transparent substrate on which is coated a very thin, high optical density, opaque body of imaging material, preferably coated with a thin abrasion-resistant protective layer. Radiant energy is then momentarily directed to the imaging material through the transparent substrate. When the heat generated by the absorbed radiant energy is above a given threshold value at a particular location of the imaging material, the material deforms and disperses thereat to form connected or unconnected globules with spaces therebetween. Upon termination of the radiant energy, the dispersed material becomes frozen in place. It was discovered that when a surface having projections and/or depressions, (for example, like that found on the surface of animal or plant tissue) is brought into contact with the recording film as described, at least the projecting portions thereof act as high resolution heat sinks which carry away heat from the imaging material in accordance with the intimacy of contact between the surface involved to be recorded and the side of the recording film contacted thereby, so that heavily heat-sinked points remain opaque and points unengaged by the surface become relatively transparent, to provide a high resolution picture of the surface topology of the contacting body.