Abstract: A light-emitting device comprising a population of quantum dots (QDs) embedded in a host matrix and a primary light source which causes the QDs to emit secondary light and a method of making such a device. The size distribution of the QDs is chosen to allow light of a particular color to be emitted therefrom. The light emitted from the device may be of either a pure (monochromatic) color, or a mixed (polychromatic) color, and may consist solely of light emitted from the QDs themselves, or of a mixture of light emitted from the QDs and light emitted from the primary source. The QDs desirably are composed of an undoped semiconductor such as CdSe, and may optionally be overcoated to increase photoluminescence.

Abstract: A light-emitting diode comprises a chip emitting visible light of a first wavelength, a light-emitting surface and a phosphor layer provided on the light-emitting surface. Said phosphor layer is capable of converting light of the first wavelength to visible light of a second wavelength. According to the invention, a part of the light-emitting surface is not covered with the phosphor layer. Preferably, the size of said surface is chosen to be such that by mixing emitted light of the first and the second wavelength substantially white light is obtained. Preferably, the surface that is not covered with the phosphor layer comprises a plurality of sub-surfaces, preferably arranged in the form of a pattern.

Abstract: A semiconductor structure including a light emitting layer disposed between an n-type region and a p-type region is attached to a compound substrate including a host which provides mechanical support to the device and a ceramic layer including a luminescent material. In some embodiments the compound substrate includes a crystalline seed layer on which the semiconductor structure is grown. The ceramic layer is disposed between the seed layer and the host. In some embodiments, the compound substrate is attached to the semiconductor structure compound substrate is spaced apart from the semiconductor structure and does not provide mechanical support to the structure. In some embodiments, the ceramic layer has a thickness less than 500 ?m.

Abstract: A device is provided with an array of a plurality of phosphor converted light emitting devices (LEDs) that produce broad spectrum light. The phosphor converted LEDs may produce light with different correlated color temperature (CCT) and are covered with an optical element that assists in mixing the light from the LEDs to produce a desired correlated color temperature. The phosphor converted LEDs may also be combined in an array with color LEDs. The color LEDs may be controlled to vary their brightness such that light with an approximately continuous broad spectrum is produced. By controlling the brightness of the color LEDs, light can be produced with a fixed brightness over a large range of white points with a high color rendering quality.

Abstract: A light-emitting device comprising a population of quantum dots (QDs) embedded in a host matrix and a primary light source which causes the QDs to emit secondary light and a method of making such a device. The size distribution of the QDs is chosen to allow light of a particular color to be emitted therefrom. The light emitted from the device may be of either a pure (monochromatic) color, or a mixed (polychromatic) color, and may consist solely of light emitted from the QDs themselves, or of a mixture of light emitted from the QDs and light emitted from the primary source. The QDs desirably are composed of an undoped semiconductor such as CdSe, and may optionally be overcoated to increase photoluminescence.

Abstract: Collection optics are used with one or more light emitting diodes to produce, e.g., collimated light. The collection optics are produced in multiple pieces including a small reflective ring that surrounds the one or more light emitting diodes. The reflective ring may be positioned relative to the LEDs, using a mesa upon which the LEDs are mounted, as a lateral positioning guide. A separate upper reflector uses the reflective ring as a lateral positioning guide during assembly. The reflective ring and the upper reflector include reflective sidewalls that are approximately continuous when the reflective ring and upper reflector are assembled.

Abstract: A plurality of light emitting diode dies (LED) with associated secondary optics, which produce different light distribution patterns, are combined to produce an efficient light source having a desired illumination pattern. By way of example, a first LED may include a lens that produces a light distribution pattern with a maximum intensity at the center while a second LED may use a lens that produces a light distribution pattern with a maximum intensity that surrounds the maximum intensity of the pattern produced by the first LED. The light from the LEDs can then be combined to produce a desired illumination pattern. Additional LEDs and lenses, e.g., having different light distribution patterns may be used if desired. Moreover, a variable current driver may be used to vary the amount of current to the different LEDs, such that the combined illumination pattern may be varied as desired.

Abstract: A light system includes a plurality of light emitting elements, such as light emitting diodes, arranged in an array. One or more light emitting elements are positioned in a center region of the array. The light emitting elements in the center region have superior performance, such as luminance and/or efficiency, relative to the remainder of the light emitting elements in the array. A second region that is outside the center region, i.e., farther from the center of the array, include a second group of light emitting elements that have superior performance relative to any additional light emitting elements in the array. The array may include additional regions farther from the center of the array that include light emitting elements with lower performance. A collection optic having an optical axis is optically coupled to the array such that the optical axis is located at approximately the center of the array.

Abstract: A light emitting device includes a number of light emitting diode dies (LEDs) mounted on a shared submount and covered with a single lens element that includes a corresponding number of lens elements. The LEDs are separated from each other by a distance that is sufficient for lens element to include separate lens elements for each LED. The separation of the LEDs and lens elements may be configured to produce a desired amount of light on a target at a predefined distance. In one embodiment, the lens elements are approximately flat type lens elements, such as Fresnel, TIR, diffractive lens, photonic crystal type lenses, prism, or reflective lens.

Abstract: An imaging system includes a wavelength dependent aperture stop, which transmits light with different ranges of wavelengths through apertures of different diameters. Thus, different colored light will have different F-stops, which can be selected based on the power transfer and image quality requirements for the different colored light. For example, a smaller F-stop may be used with a weaker light source to produce a higher throughput for a specific range of wavelengths. Accordingly, the optical system's design and optimization is wavelength and F-stop dependent.

Abstract: A light emitting device includes a substrate, a textured layer overlying the substrate, at least one III-nitride layer overlying the textured layer, and a substantially planar light emitting region. Devices incorporating scattering layers may be formed by several different methods. In a first method, an epitaxial layer is deposited then etched to form the textured layer. In a second method, a photomask is deposited and patterned to create openings in the photomask. The textured layer is then preferentially deposited in the openings formed in the photomask. In a third method, the textured layer is deposited under conditions that favor three-dimensional growth, then optionally annealed.

Abstract: Light emitting devices with improved light extraction efficiency are provided. The light emitting devices have a stack of layers including semiconductor layers comprising an active region. The stack is bonded to a transparent optical element having a refractive index for light emitted by the active region preferably greater than about 1.5, more preferably greater than about 1.8. A method of bonding a transparent optical element (e.g., a lens or an optical concentrator) to a light emitting device comprising an active region includes elevating a temperature of the optical element and the stack and applying a pressure to press the optical element and the light emitting device together. A block of optical element material may be bonded to the light emitting device and then shaped into an optical element. Bonding a high refractive index optical element to a light emitting device improves the light extraction efficiency of the light emitting device by reducing loss due to total internal reflection.

Abstract: Light emitting devices with improved light extraction efficiency are provided. The light emitting devices have a stack of layers including semiconductor layers comprising an active region. The stack is bonded to a transparent lens having a refractive index for light emitted by the active region preferably greater than about 1.5, more preferably greater than about 1.8. A method of bonding a transparent lens to a light emitting device having a stack of layers including semiconductor layers comprising an active region includes elevating a temperature of the lens and the stack and applying a pressure to press the lens and the stack together. Bonding a high refractive index lens to a light emitting device improves the light extraction efficiency of the light emitting device by reducing loss due to total internal reflection. Advantageously, this improvement can be achieved without the use of an encapsulant.

Abstract: A method for forming a luminescent layer on a light emitting semiconductor device includes positioning a stencil on a substrate such that a light emitting semiconductor device disposed on the substrate is located within an opening in the stencil, depositing a stenciling composition including luminescent material in the opening, removing the stencil from the substrate, and curing the stenciling composition to a solid state. The resulting light emitting device includes a stack of layers including semiconductor layers comprising an active region and a luminescent material containing layer having a substantially uniform thickness disposed around at least a portion of the stack. A surface of the luminescent material containing layer not adjacent to the stack substantially conforms to a shape of the stack. In one embodiment, the light emitting device emits white light in a uniformly white spatial profile.

Abstract: A lamp has LED sources that are placed about a lamp axis in an axial arrangement. The lamp includes a post with post facets where the LED sources are mounted. The lamp includes a segmented reflector for guiding light from the LED sources. The segmented reflector includes reflective segments each of which is illuminated primarily by light from one of the post facets (e.g., one of the LED sources on the post facet). The LED sources may be made up of one or more LED dies. The LED dies may include optic-on-chip lenses to direct the light from each post facet to a corresponding reflective segment. The LED dies may be of different sizes and colors chosen to generate a particular far-field pattern.

Abstract: A device is provided with at least one light emitting device (LED) die mounted on a submount with an optical element subsequently thermally bonded to the LED die. The LED die is electrically coupled to the submount through contact bumps that have a higher temperature melting point than is used to thermally bond the optical element to the LED die. In one implementation, a single optical element is bonded to a plurality of LED dice that are mounted to the submount and the submount and the optical element have approximately the same coefficients of thermal expansion. Alternatively, a number of optical elements may be used. The optical element or LED die may be covered with a coating of wavelength converting material. In one implementation, the device is tested to determine the wavelengths produced and additional layers of the wavelength converting material are added until the desired wavelengths are produced.

Abstract: A device is provided with an array of a plurality of phosphor converted light emitting devices (LEDs) that produce broad spectrum light. The phosphor converted LEDs may produce light with different correlated color temperature (CCT) and are covered with an optical element that assists in mixing the light from the LEDs to produce a desired correlated color temperature. The phosphor converted LEDs may also be combined in an array with color LEDs. The color LEDs may be controlled to vary their brightness such that light with an approximately continuous broad spectrum is produced. By controlling the brightness of the color LEDs, light can be produced with a fixed brightness over a large range of white points with a high color rendering quality.

Abstract: A system includes a radiation source capable of emitting first light and a fluorescent material capable of absorbing the first light and emitting second light having a different wavelength than the first light. The fluorescent material is a phosphor having the formula (Lu1-x-y-a-bYxGdy)3(Al1-zGaz)5O12:CeaPrb wherein 0<x<1, 0<y<1, 0<z?0.1, 0<a?0.2 and 0<b?0.1. In some embodiments, the (Lu1-x-y-a-bYxGdy)3(Al1-zGaz)5O12:CeaPrb is combined with a second fluorescent material capable of emitting third light. The second fluorescent material may be a red-emitting phosphor, such that the combination of first, second, and third light emitted from the system appears white.

Abstract: In a lighting arrangement comprising a LED array and a DC-DC-converter for supplying the LED array, the DC-DC-converter is an up-converter and the LED array is coupled between an input terminal and an output terminal. The up-converter generates a very low voltage over the LED array without making use of a transformer.

Abstract: III-nitride or III-phosphide light emitting devices include a light emitting region disposed between a p-type region and an n-type region. At least one heavily doped layer is disposed within either the n-type region or the p-type region or both, to provide current spreading.