HEMISPHERICAL LUMINESCENCE DIODE PRODUCING A REAL IMAGE OF THE P-N JUNCTION

1,164,377. Semi-conductor electroluminescent devices. SIEMENS A.G. 21 March, 1967 [23 March, 1966], No. 13325/67. Heading H1K. [Also in Division C4] The semi-conductor body of an electroluminescent diode includes a lens portion 21 comprising at least the first element of an optical image-forming system for focusing the light emitted by the junction 23. In the GaAs diode shown the junction 23 is formed by diffusion and is situated in a stem-like extension 22 attached to a polished hemispherical lens portion 21, the junction being spaced from the lens by a sufficient distance to permit formation of a real image outside the diode. Electrodes to the device comprise an alloyed indium layer 24 on the P- type portion, and a perforated disc 25 of tinplated "Kovar" (Registered Trade Mark) alloyed to the N-type region and serving as a cooling plate. Preferred diode dimensions are given for the cases in which the image-forming system comprises a series of lenses or a fibrous glass light conductor. The lens of the diode may alternatively constitute the entire image-forming system. The image may be formed on a radiation detector surface.