摘要:
The present invention provides an LED device comprising a phosphor-converting substrate that converts primary light emitted by the LED, which is blue light, into one or more other wavelengths of light, which then combine with unconverted primary light to produce white light. The substrate is a single crystal phosphor having desired luminescent properties. The single crystal phosphor has the necessary lattice structure to promote single crystalline growth of the light-emitting structure of the LED device. Moreover, the thermo-mechanical properties of the substrate are such that the introduction of excessive strain or cracks in the epitaxial films of the LED device is prevented. The characteristics of the substrate, i.e., the dopant concentration and thickness, are capable of being precisely controlled and tested before the LED device is fabricated so that the fraction of primary light that passes through the substrate without being converted is predictable and controllable. Likewise, the fraction of primary light that is converted by the substrate into one or more other wavelengths is predictable and controllable. By precisely controlling these fractions, phosphor-converted LED devices can be achieved that produce uniform, high-quality white light.
摘要:
An apparatus is disclosed for use with a device for processing a crystal having crystallographic axes and crystallographic facets on its surface. A light beam is supplied towards the facets where the light beam has a selected spatial relationship to the device. The directions of reflections of the light beam from the facets are detected to determine the spatial relationship between one crystallographic axis and the processing device so that the body is processable using the device in reference to the crystallographic axis. A U-shaped member is placed with its open ends in contact with or adjacent to a reference surface of the processing device. The U-shaped member encloses and is urged against the body when the body is rotated about a reference direction of the device The U-shaped member is of such dimensions that the surface portions of the body at distances smaller than a predetermined distance will cause both ends of the member to contact the reference surface.
摘要:
A method for forming an ohmic interface between unipolar (isotype) compound semiconductor wafers without a metallic interlayer and the semiconductor devices formed with these ohmic interfaces are disclosed. The ohmic interface is formed by simultaneously matching the crystallographic orientation of the wafer surfaces and the rotational alignment within the surfaces of the two wafers and then subjecting them to applied uniaxial pressure under high temperatures to form the bonded ohmic interface. Such an ohmic interface is required for the practical implementation of devices wherein electrical current is passed from one bonded wafer to another.
摘要:
A method for forming an ohmic interface between unipolar (isotype) compound semiconductor wafers without a metallic interlayer and the semiconductor devices formed with these ohmic interfaces are disclosed. The ohmic interface is formed by simultaneously matching the crystallographic orientation of the wafer surfaces and the rotational alignment within the surfaces of the two wafers and then subjecting them to applied uniaxial pressure under high temperatures to form the bonded ohmic interface. Such an ohmic interface is required for the practical implementation of devices wherein electrical current is passed from one bonded wafer to another.