| 摘要 |
In an image display device comprising a photoconductive layer for collecting an incident radiation image and a field-strength-sensitive medium affected thereby, which medium in turn modulates an auxiliary light beam, the photoconductive layer has to be effectively screened from the auxiliary light. According to the invention an intermediate layer is used for this purpose which consists of a semiconductor whose energy gap is a few tenths ev. smaller than the energy gap of the photoconductive material. This is fulfilled by using copper-activated CdSe for the photoconductor and a semiconductor of the group CdTe, GeS and Sb2Se3 and mixtures thereof for the intermediate layer. The latter two materials have the advantage that they can be vapor-deposited on a substrate which is at room temperature. The vapor-deposited substances are thus prevented from producing intermediate levels in the photoconductor, in which case the long-wave portion of the auxiliary light passing through the intermediate layer might release charge carriers in the photoconductor. A layer consisting of 3 parts by weight of Sb2Se3 and 1 part by weight of GeS satisfies in particular the relevant requirements owing to the fine crystalline form of a layer of this material when it is vapor-deposited on the photoconductive layer which is at room temperature.
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