An electroluminescent diode which includes an electromagnetic radiation emitting PN junction formed by diffusing, into both surfaces of a semiconductor slice of a first conductivity, a dopant material of opposite type conductivity. Contact metallizations are mounted within windows in an insulating barrier which covers said diode so as to form electrical contacts engaging both the N and P type areas of the diode. An annular reflector metallization pad is mounted on the surface of the device over the PN junction and spaced from one surface of the semiconductor material by the insulating coating so as to reflect light out through the surface opposite to that on which an anti-reflection coating has been placed.
A semiconductor light emitting device comprises a laminated semiconductive structure including a substrate, an active layer thereon and a second layer adjacent the active layer remote from the substrate, the second layer having an inner region of high carrier concentration and an outer region of lower carrier concentration. An insulative layer is on the second layer, the insulative layer having a window coaxial with and larger than the inner region. A first electrode deposited on the insulative layer establishes an ohmic contact with the inner region of the second layer and a Schottky-barrier contact with the outer region. A second electrode is provided on the substrate opposite to the first electrode, the second electrode having a window for allowing light to leave therethrough.
In a light emitting diode comprising a plurality of layers deposited on a substrate, the substrate is etched so as to reduce the area in which the substrate is attached to the plurality of layers. The reduction in the area of attachment results in less light being absorbed by the substrate and thus more total light shining forth from the light emitting diode.
A light emitting diode assembly which includes a light reflector formed at one end of, and as an integral part of a first electrical supply lead; a light emitting diode mounted within the reflector, one side of the diode junction being connected in electrical contact with the reflector which in association with the first lead provides a high heat sinking facility; and a second electrical supply lead one end of which is connected in electrical contact with the other side of the diode junction. The diode, the reflector and the said one end of the second lead are encapsulated in a bead of a light transparent material. A method producing the assembly using a U-shaped member from which the first and second leads are formed in described.
An object of the invention is to prolong the seal life of a color EL display apparatus. The initial thickness of a light-transmitting main substrate is larger than a predetermined reference thickness WC. First, a plurality of thin-film EL devices are formed on one surface of the main substrate. Then, a sealing substrate having a concave portion formed in one surface thereof is bonded onto the one surface of the main substrate at predetermined intervals. Then, a protective material for protecting the thin-film EL devices is filled in the gap between the one surface of the main substrate and the sealing substrate. Then, the main substrate is processed so as to have the reference thickness WC. Then, a color filter portion is formed on the other surface of the main substrate. Lastly, a reinforcing substrate is attached to the other surface of the main substrate with the color filter portion in between. Consequently, a color EL display apparatus having a sealing portion of the same structure as that of the currently-used sealing portion is completed.
An electro-luminescent diode having a luminous surface which is defined by a thinned portion comprising zones with emitting junctions, the zones occupying only a portion of the luminous surface. The composition of the thinned portion allows multiple reflection of light to occur and enables light generated in the diode and totally internally reflected to be reflected back from a diffusing reflector to emerge and increase the intensity of light efficiency of the diode.
