| 摘要 |
1341221 Electroluminescence MOTOROLA Inc 6 Jan 1971 [16 Feb 1970] 631/71 Heading C4S [Also in Division H1] A light emitting diode source comprises a wafer of s/c material of one conductivity type and having planar top and bottom surfaces, mounting plate electrode 60, at least one interface 66 of opposite conductivity type material extending perpendicularly to the top surface and extending at least 1¢ mm. from that surface, the area of the PN-junction at the interface being substantially larger than the PN area in the bottom wall area of the cavity, an electrical bias across the junction providing the majority of light along the side walls and emitted from the top surface. A hole may be formed in the top surface and may be at least partially filled with opposite conductivity type material. Specified materials are GaAs, GaP, GaAs 1-x P x , Ga x Al 1-x As, and Ga x In 1-x P. Light is stated to emit most favourably from a PN-junction intersection with an external surface due to refractive index and absorption coefficient considerations, the depletion region acting as a waveguide. Excavations may be by etching, cutting, or the article may be cast. In Fig. 2 (not shown) with hole (14) the N and P materials may be reversed. The junction may meander as in Fig. 3 (not shown). In Fig. 4, slab 62 of P material may extend along the other edges to inhibit emission parallel to electrode 60, and the dimensions away from electrode 60 may be relatively shorter than shown compared with dimensions parallel to the electrode. Fig. 5 (not shown) has hole (68) with thin layer (70) of N material on its inside surface, a small margin supporting bonding pad for lead (74). Hole (68) may be 25 times as thick as coating (70) and PN- junction (78) may reinforce the light emission. In Fig. 6 (not shown), layer (70) with bonding pad (73) extends round all the upper surface, the former set back by the depletion layer thickness. Figs 7 and 8 (not shown) include cylindrical grooves (84) providing cylindrical PN- junctions. Block (82) may be other than square, and the grooves may be other than cylindrical including intersecting shapes. Junctions may be produced by diffusion, alloying or epitaxial deposition.
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