Abstract: High resolution light emitting diode (LED) displays can be formed from freestanding small epitaxial LED chips or small LED arrays. The addressing elements for the LED display can be active matrix backplane. The LED display may use isotropic and directional luminescent elements. The LED displays can be flat screen, fixed image, projection or low resolution or high resolution direct view. A macro freestanding epitaxial LED chip with multiple addressable pixels is described which forms a complete microdisplay.

Abstract: Thin flat crack-free freestanding nitride layers are fabricated by laser patterning of the interface and/or opposing surface of the nitride layer. The nitride layer is substantially flat once removed from the non-native substrate. The thin flat crack free nitride layers are between 3 and 250 microns thick and can have areas greater than 1 cm2.

Abstract: LEDs are mounted onto a flat, thermally conductive, substrate, which is folded to form a light recycling cavity. A planar substrate is first coated with a metal layer, which is patterned to electrically connect the LEDs and to form bonding pads for wirebonds to connect the LEDs to external circuitry. The LEDs are mounted on the substrate. The substrate is then scribed on the backside to form the folds. The LED dies are then attached onto the metal islands (pads) defined on the substrate and wirebonds are used to connect the top side of the LED to adjacent patterned metal islands (pads) on the substrate. The substrate is then folded into a light recycling cavity where the LEDs are facing the inside of the cavity.

Abstract: Reflector designs for a large area panel light source create induced draft cooling means adjacent to the panel light source. The panel light source has a wavelength conversion element on a solid state light source for emitting light of a first and second wavelength to form a broader emission spectrum of light from the panel light source.

Abstract: Subtractive and/or additive techniques can adjust both color and/or intensity in solid wavelength conversion materials.

Abstract: Thermal boundary resistances within nitride semiconductor LEDs are reduced or eliminated by forming a thick nitride epitaxial layer, which can be separated from a growth substrate, and by reducing the number of thermal boundary layers during laser lift-off. The thermal boundary resistances within nitride semiconductor LEDs can also be reduced or eliminated by forming a plurality of thin nitride epitaxial layers.

Abstract: A substrate-free semiconducting sheet has an array of semiconducting elements dispersed in a matrix material. The matrix material is bonded to the edge surfaces of the semiconducting elements and the substrate-free semiconducting sheet is substantially the same thickness as the semiconducting elements.

Abstract: An optical element such as an interference filter will have adjacent layers of different indexes of refraction but formed of the same optical material. An optical element such as a diffraction grating or beam-splitter will have adjacent sections of different indexes of refraction in the same optical material layer. An optical element such as a waveguide will have a core layer of a higher index of refraction partially or completely surrounded by a cladding layer of a lower index of refraction formed of the same optical material.

Abstract: A light emitting diode (LED) chip has a multilayer semiconductor structure that is at least 10 microns thick and does not require an attached growth substrate or transfer substrate for structural rigidity or support. The multilayer semiconductor structure includes a first doped layer, a second doped layer and an active region interposed between the first doped layer and the second doped layer. Optionally, the multilayer semiconductor structure includes an undoped layer. At least one of the layers of the multilayer semiconductor structure is at least 5 microns thick and is preferably deposited by hydride vapor phase epitaxy.

Abstract: A solid-state light source includes at least one stack of light emitting elements. The elements are an inorganic light emitting diode chip and at least one wavelength conversion chip or the elements are a plurality of light emitting diode chips and one or more optional wavelength conversion chips. The wavelength conversion chip may include an electrical interconnection means. The light emitting diode chip may include at least one GaN-based semiconductor layer that is at least ten microns thick and that is fabricated by hydride vapor phase epitaxy. A method is described for fabricating the solid-state light source.

Abstract: A LED light source is integrated with a heatsink and a collimator. Four isolated heatsinks form an optical taper in which a single color LED is mounted. The LEDs are arranged to form a reflective light recycling cavity. Up to four different colors can be combined inside the light recycling cavity to form a uniform and homogenous mixing of the colors at the exit aperture of the light recycling cavity and/or the exit aperture of the collimator/heatsink.

Abstract: A light emitting diode light source with mirrored surfaces is formed on a planar substrate which, when folded, forms both a light recycling cavity and an optical taper at the end of the light recycling cavity.

Abstract: A substrate-free LED chip has a multilayer semiconductor structure at least 10 microns thick provided on a growth substrate. One or more arrays of parallel streets are etched into the multilayer semiconductor structure using a first pulsed laser beam. By scanning a second pulsed laser beam through the growth substrate to the multilayer semiconductor structure, the LED chips are detached from the growth substrate while simultaneously forming surface features on the chips.

Abstract: A method for fabricating substrate-free LED chips has a multilayer semiconductor structure at least 10 microns thick provided on a growth substrate. One or more arrays of parallel streets are etched into the multilayer semiconductor structure using a first pulsed laser beam. By scanning a second pulsed laser beam through the growth substrate to the multilayer semiconductor structure, the LED chips are detached from the growth substrate while simultaneously forming surface features on the chips.

Abstract: The invention is method for fabricating light emitting diodes. A layered semiconductor structure is provided on a growth substrate. The method includes using a pulsed laser to form an interfacial layer between the layered semiconductor structure and the growth substrate for subsequent substrate detachment and to simultaneously form light extracting elements on the layered semiconductor structure. The method reduces the number of steps required to fabricate a light emitting diode.

Abstract: A light conversion device and high-intensity, solid-state light source utilize wavelength conversion elements with a thermal conductivity greater than 1 watt per meter per degree Kelvin (W/m-K). Exemplary materials that have high thermal conductivity include monocrystalline solids, polycrystalline solids, substantially densified ceramic solids, amorphous solids or composite solids. The light conversion device and high-intensity, solid-state light source have at least one heat sink that is in direct thermal contact with the wavelength conversion element. The heat sink quickly dissipates heat generated within the wavelength conversion element in order to prevent the wavelength conversion element from overheating and undergoing thermal quenching of the wavelength conversion and light emission.

Abstract: A controlled electron beam and heat will decrease the birefringence of a halogenated optical material under tensile stress. The electron beam and heat irradiation will occur in a chamber under near vacuum conditions. After electron beam irradiation and heating, the crystalline structure of the halogenated optical material layer has been randomized and made amorphous. The electron beam irradiation and heating will lower the high index of refraction of the halogenated optical material under stress and raise the low index of refraction of the halogenated optical material under stress. The differences in index of refraction between the high index of refraction area of and the low index of refraction area decrease which decreases the birefringence of the halogenated optical material under stress.

Abstract: High brightness LEDs are mounted directly on a heat pipe or are mounted on a substrate, which is mounted on the heat pipe. The heat pipe can be a common electrode for the LEDs mounted on the heat pipe. Multiple heat pipes can be arranged so that the LED arrays form a light recycling cavity to emit and reflect light.

Abstract: A wavelength conversion chip is formed by depositing a wavelength conversion material layer on a substrate, segmenting the wavelength conversion layer into a plurality of wavelength conversion chips, and then removing the wavelength conversion chips from the substrate. The wavelength conversion of the chips can be increased by thermal annealing or radiation annealing of the wavelength conversion material. Optical coatings or light extraction elements can be fabricated on the wavelength conversion layer.

Abstract: The exposure of selected optical materials to large area electron beam irradiation can raise the refractive index of the optical material to allow the fabrication of waveguides, optical fibers, gradient index lenses, interference filters, antireflection coatings, heat reflective thermal control coatings and other optical elements.