Elektro-optische Vorrichtung

摘要

An optical transducer comrpises at least three component arranged in parallel, a photo-conductive element 2, Fig. 1, a light source 3 for optical feedback (positive or negative) to element 2, and an output light source 5, and further has a variable impedance 4 in series with the light source 3 enabling variation of the optical feedback without altering the maximum voltage obtainable, across the light source 5. The light sources 3 and 5 may be electro-luminescent cells, and the impedance 4 may be a photo-conductor itself illuminated by a variable light source. In the device of Fig. 2, photo-conductive layer 12 is the component 2, electro-luminescent layer 13 is the component 3, photo-conductive layer 14 is the component 4, activated by external lamps 35, 36, and the electro-luminescent layer 15 is the output source 5; the electrode 24, which is opaque, prevents optical feedback from the output source 5, and is analogous to the optical barrier 6 of Fig. 1. In a further embodiment, two such cells are mounted side-by-side, and the optical feedback is so adjusted that each has only two stable states, and the two cells are so inter-connected that switching one cell to one state switches the other to the other state. In the image intensifier of Fig. 8, the curved glass plate 500 carries interdigital electrodes 511 and 512. A red-emitting Zn Se activated by Cu and Al phosphor is positioned on the strips 511, and a similar ZnS phosphor is positioned on the strips 512, together with a reflective layer 513, e.g. titanium oxide in glass powder. The space between the strips is filled with sintered black glass 515. On the strips are positioned pyramids of a current-diffusing layer, e.g. CdS activated with chlorine in glass powder 516 and glass with aluminium oxide as filler, 517. The walls of the pyramids are covered with a photo-conductor 502, connected to electrode 520 mounted on a flexible glass plate 521.