Abstract:
A wavelength converter for an LED is described that comprises a substrate of monocrystalline garnet having a cubic crystal structure, a first lattice parameter and an oriented crystal face. An epitaxial layer is formed directly on the oriented crystal face of the substrate. The layer is comprised of a monocrystalline garnet phosphor having a cubic crystal structure and a second lattice parameter that is different from the first lattice parameter wherein the difference between the first lattice parameter and the second lattice parameter results in a lattice mismatch within a range of ±15%. The strain induced in the phosphor layer by the lattice mismatch shifts the emission of the phosphor to longer wavelengths when a tensile strain is induced and to shorter wavelengths when a compressive strain is induced. Preferably, the wavelength converter is mounted on the light emitting surface of a blue LED to produce an LED light source.
Abstract:
A wavelength converter for an LED is described that comprises a substrate of monocrystalline garnet having a cubic crystal structure, a first lattice parameter and an oriented crystal face. An epitaxial layer is formed directly on the oriented crystal face of the substrate. The layer is comprised of a monocrystalline garnet phosphor having a cubic crystal structure and a second lattice parameter that is different from the first lattice parameter wherein the difference between the first lattice parameter and the second lattice parameter results in a lattice mismatch within a range of ±15%. The strain induced in the phosphor layer by the lattice mismatch shifts the emission of the phosphor to longer wavelengths when a tensile strain is induced and to shorter wavelengths when a compressive strain is induced. Preferably, the wavelength converter is mounted on the light emitting surface of a blue LED to produce an LED light source.
Abstract:
There is herein described a light source that homogenizes the light produced by a large area array of forward directed LEDs mounted on highly reflective substrate, while achieving a low-profile form factor and maintaining high efficacy. The LED light source employs a diffuser comprised of two diffusing layers: a low scattering diffusing layer bonded to the LEDs and a high scattering diffusing layer that is bonded to the low scattering diffusing layer. The LED light source achieves good diffuse illumination with a thin diffuser by making use of a light channeling effect between the highly reflective substrate and the high backscattering from the high scattering diffusing layer.
Abstract:
A method and apparatus for providing electro-static discharge (ESD) protection to light emitting diode (LED) systems on printed circuit boards (PCBs). Protection is provided by ESD diodes deposited on the PCBs configured as flexible substrates. Various deposition techniques are employed including chemical vapor deposition, pulsed laser deposition and atomic layer deposition.
Abstract:
A lighting module comprising a base panel and a plurality of light-emitting diode (LED) chips attached directly to the base panel. The LED chips are in electrical communication with conductive traces on the base panel, which deliver a current to the LED chips. Various embodiments of this generally described lighting module are also presented. Additionally, methods of preparing such a lighting module, and system components of the lighting module are presented.
Abstract:
A flexible light engine, comprising insulating lower and upper laminate sheets; first and second electrically conductive metallic bus bars between the sheets; a plurality of electrically conductive metallic conductors between the sheets being disposed laterally between the bus bars, wherein each conductor defines two metallic contacts exposed in register with adjacent perforations in the perforated upper sheet; wherein each of the bus bars further comprises respective at least two interconnectors, and wherein the conductors are connected to respective interconnectors to define at least two series circuits and connectable in parallel between the bus bars, wherein each of the series circuits comprises a subset of the plurality of metallic conductors; and a plurality of LEDs attached to the contacts defining at least two series LED strings and connected in parallel between the bus bars, each said LED string comprising a plurality of LEDs.
Abstract:
Techniques are disclosed for attaching SMDs to a flexible substrate using conductive epoxy bond pads. Each bond pad includes a set of elongated strips of conductive epoxy that are applied and cured onto the flexible substrate in an adjacent and parallel fashion. The bond pads are used to attach SMDs to the flexible substrate and also provide the conductive contacts for a printed circuit. A circuit may be printed on the flexible substrate using conductive ink that partially covers the bond pads, leaving a portion of the pads exposed. A second layer or strip of conductive epoxy may be applied over and across the exposed portions of the bond pad strips in order to attach an SMD. The number, size, and orientation of the epoxy bond pad strips may be determined by the amount of bending the flexible substrate is expected to withstand and/or the orientation of the bend.
Abstract:
Techniques are disclosed for making a flexible laminated circuit board using a metal conductor onto which a SMD may be attached. Conductive metal strips may be laminated to form a flexible substrate and the metal strips may then be perforated for the placement of LED package leads. The LED packages may be attached to the conductive strips using solder or a conductive epoxy and the upper laminate layer may include perforations exposing portions of the metal strips for the attachment of the LED packages. Alternatively, strings of LED packages may be fabricated by attaching LED packages to conductive strips and these strings may be laminated between flexible sheets to form a laminated LED circuit. Plastic housings may aid in attaching the LED packages to the conductive strips. The plastic housings and/or the laminate sheets may be made of a reflective material.