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Photographic Analog To Digital Conversion

IP.com Disclosure Number: IPCOM000094843D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Zweig, HJ: AUTHOR

Abstract

A multilayer film can be made which has a developed density versus exposure characteristic such that the structure can be used as an analog-to-digital converter. The top left drawing shows a two-layer film. The graph at the top right shows the developed density versus exposure characteristics of the two layers. The top layer becomes transparent with increased exposure and the bottom layer becomes opaque with increased exposure. The composite characteristic of the two layers, therefore, has a gap or dip in the composite characteristic between the exposure magnitudes designated a and b.

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Photographic Analog To Digital Conversion

A multilayer film can be made which has a developed density versus exposure characteristic such that the structure can be used as an analog-to- digital converter. The top left drawing shows a two-layer film. The graph at the top right shows the developed density versus exposure characteristics of the two layers. The top layer becomes transparent with increased exposure and the bottom layer becomes opaque with increased exposure. The composite characteristic of the two layers, therefore, has a gap or dip in the composite characteristic between the exposure magnitudes designated a and b.

The lower left drawing shows a film which has four layers which are divided into two groups. The top layer is identical to the previously described two-layer film and the second group has a similar characteristic but for a different wavelength of light. Furthermore, the gap indicated by the exposure value c and d in the right-hand middle drawing occurs at a higher exposure. The composite characteristic of the four-layer structure shown in the bottom right drawing has two dips between the exposures a and b and c and d.

Only two groups are shown on top of each other. However, a composite structure can be made of a plurality of groups. Each is responsive to a different frequency. Each provides a gap or dip at a different exposure.

The multilayer structure shown can be used as follows. The film is exposed by a light source which generates light...