DEVICE FOR SECRETLY OBSERVING VISUAL INTELLIGENCE

摘要

1380357 "Mind-reading" trick H N BRAUNHUT 12 July 1972 [1 Nov 1971] 32524/72 Heading A6H A device for secretly observing visual intelligence on a sheet 10 comprises a louvred array 32 of alternate transparent and opaque inclined zones, the latter allowing visual intelligence to be seen through the array from one direction C and not from another D, and an opaque means 40, 38 so that the device appears to be completely opaque from both directions when the sheet 10 is absent. A transparent sheet 29 is wrapped around the array 32, a transparent sheet 34 and the array comprising the opaque sheet 38 and the inner transparent sheet 40. In a modification, the sheet 38 may be replaced by a second array 32.