Abstract:
A lighting apparatus for emitting polarized white light, which includes at least a first light source for emitting primary light comprised of one or more first wavelengths and having a first polarization direction; and at least a second light source for emitting secondary light in the first polarization direction, comprised of one or more secondary wavelengths, wherein the first light and the secondary light are combined to produce a polarized white light. The lighting apparatus may further comprise a polarizer for controlling the primary light's intensity, wherein a rotation of the polarizer varies an alignment of its polarization axis with respect to the first polarization direction, which varies transmission of the primary light through the polarizer, which controls a color co-ordinate or hue of the white light.
Abstract:
A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.
Abstract:
III-V micro light-emitting diodes (LEDs) are fabricated using a photoelectrochemical (PEC) etch. A sacrificial layer and III-V device layers are epitaxially grown on a host substrate, wherein the III-V device layers are patterned to form the micro-LEDs. The sacrificial layer is removed by a photoelectrochemical (PEC) etch, so as to fully or partially separate the micro-LEDs from the substrate, before or after the micro-LEDs are bonded to a submount or intermediate substrate. The micro-LEDs may be bonded to a submount with a polymer film deposited thereon, wherein the polymer film with the micro-LEDs is subsequently delaminated from the submount. Alternatively, the intermediate substrate may be a transfer medium, wherein the micro-LEDs are separated from the host substrate by mechanical fracturing, and then bonded to a second substrate, after which the intermediate substrate is removed, wherein a third substrate may be bonded to exposed surfaces of the transferred micro-LEDs.
Abstract:
A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an α-axis direction comprising a 0.15° or greater miscut angle towards the α-axis direction and a less than 30° miscut angle towards the α-axis direction.
Abstract:
A method for growth and fabrication of semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices, comprising identifying desired material properties for a particular device application, selecting a semipolar growth orientation based on the desired material properties, selecting a suitable substrate for growth of the selected semipolar growth orientation, growing a planar semipolar (Ga,Al,In,B)N template or nucleation layer on the substrate, and growing the semipolar (Ga,Al,In,B)N thin films, heterostructures or devices on the planar semipolar (Ga,Al,In,B)N template or nucleation layer. The method results in a large area of the semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices being parallel to the substrate surface.
Abstract:
A method for increasing the luminous efficacy of a white light emitting diode (WLED), comprising introducing optically functional interfaces between an LED die and a phosphor, and between the phosphor and an outer medium, wherein at least one of the interfaces between the phosphor and the LED die provides a reflectance for light emitted by the phosphor away from the outer medium and a transmittance for light emitted by the LED die. Thus, a WLED may comprise a first material which surrounds an LED die, a phosphor layer, and at least one additional layer or material which is transparent for direct LED emission and reflective for the phosphor emission, placed between the phosphor layer and the first material which surrounds the LED die.
Abstract:
A method for the reuse of gallium nitride (GaN) epitaxial substrates uses band-gap-selective photoelectrochemical (PEC) etching to remove one or more epitaxial layers from bulk or free-standing GaN substrates without damaging the substrate, allowing the substrate to be reused for further growth of additional epitaxial layers. The method facilitates a significant cost reduction in device production by permitting the reuse of expensive bulk or free-standing GaN substrates.
Abstract:
An efficient and stable, high-power, laser-driven white light source using one or more phosphors deposited on a thermally conductive substrate that is either transparent or reflective and placed at a remote distance from the laser source. The present invention relates generally to a high-power, laser-driven, white light source using one or more phosphors.
Abstract:
A high-power, high-brightness lighting system for large venue lighting, which includes a laser diode as the excitation source and one or more phosphor materials placed at a remote distance from the laser source. The invention offers a lighting system with the advantages of high brightness, high efficiency, high luminous efficacy, long lifetimes, quick turn-on times, suitable color properties, environmental sustainability, and easy maintenance, which may allow for smart and flexible control over large area lighting systems with resulting savings in operating and maintenance costs.