Abstract: Light-emitting systems (e.g., projection systems) that comprise multiple light-emitting diodes (LEDs) are described herein. For example, the systems may include dual (i.e., two) primary red LEDs.

Abstract: Aspects of the present disclosure relate to a light-emitting system comprising a plurality of LEDs having relatively small nearest-neighbor distances (e.g., a close-packed array of LEDs). In some cases, one or more LEDs of the plurality of LEDs comprise a via between a semiconductor layer (e.g., an n-type semiconductor layer forming part of a p-n junction) and a heat dissipation substrate. The presence of the vias may advantageously reduce or eliminate current crowding and may allow the LEDs to be operated at a high current density (e.g., at least 1A/mm2). In some cases, one or more LEDs of the plurality of LEDs comprise a first contact pad (e.g., an n-side contact pad) and a second contact pad (e.g., a p-side contact pad) positioned in any location, which may allow the LEDs to be configured in series or in parallel, or to be individually addressable. The first and second contact pads of the LEDs may be electrically connected to other elements of the light-emitting system (e.g.

Abstract: Light-emitting systems (e.g., projection systems) that comprise multiple light-emitting diodes (LEDs) are described herein. For example, the systems may include dual (i.e., two) primary red LEDs.

Abstract: Methods and apparatus are provided for LED packages with surface textures. In one novel aspect, microstructures are formed on surfaces of the LED package such that light extract efficiency is improved. In one embodiment, the LED package has a silicone-encapsulating layer scattered with phosphors. In another embodiment, the LED package has a leadframe substrate. The microstructure can be micro lens, micro dents, micro pillars, micro cones, or other shapes. The microstructures can be periodically arranged or randomly arranged. In one novel aspect, the compression molding process is used to form rough surfaces. The molding block or the release film is modified with microstructures. In another novel aspect, sandblasting process is used. In one embodiment, microstructures are formed on sidewalls using the sandblasting process. The hardness, the angle, and/or the size of the blasting media are selected to improve the efficiency of the LED package.

Abstract: Aspects of the present disclosure relate to a light-emitting system comprising a plurality of LEDs having relatively small nearest-neighbor distances (e.g., a close-packed array of LEDs). In some cases, one or more LEDs of the plurality of LEDs comprise a via between a semiconductor layer (e.g., an n-type semiconductor layer forming part of a p-n junction) and a heat dissipation substrate. The presence of the vias may advantageously reduce or eliminate current crowding and may allow the LEDs to be operated at a high current density (e.g., at least 1 A/mm2). In some cases, one or more LEDs of the plurality of LEDs comprise a first contact pad (e.g., an n-side contact pad) and a second contact pad (e.g., a p-side contact pad) positioned in any location, which may allow the LEDs to be configured in series or in parallel, or to be individually addressable. The first and second contact pads of the LEDs may be electrically connected to other elements of the light-emitting system (e.g.

Abstract: Methods and apparatus are provided to improve the yield rate of LED packaging using LED flip chips. In one novel aspect, extended pads made of sintered silver are disposed on the cathode and the anode of the LED flip chip. The thickness of the extended pad is from about 25 ?m to about 200 ?m. In another embodiment, the LED flip chip further comprises a phosphor layer such that the LED flip chip emits white light. In another novel aspect, the LED flip chip with extended pads made of sintered silver is produced at the wafer level. The wafer level process involves applying sintering silver pastes to the cathode and the anode of each LED flip chip formed on the wafer and sintering the wafer at a temperature about 180° C. to about 240° C. for about two hours. The wafer is cut to individual LED flip chips with extended sintered silver pads.

Abstract: Devices and methods including an LED and reflective die attach material are described herein. The devices can include a reflective substrate (e.g., a substrate that includes a silver layer) to which one or more LED die are attached using the die attach material. The die attach material extends beyond the periphery of the LED die to cover an area of the substrate surface.

Abstract: Systems including light-emitting diodes (LEDs) are provided. The systems include one or more wavelength-converting member(s) that is/are remote from the emission surface of one or more LED-based light source(s). The wavelength-converting member may be separated from the emission surface of a first LED and positioned such that light emitted from the first LED is absorbed by the wavelength-converting material. The wavelength-converting material emits secondary light having a different wavelength than the wavelength of the light emitted from the first LED. The systems may include a second light source comprising a second LED configured to emit light having a wavelength from an emission surface and a wavelength-combining element configured to combine the secondary light from the wavelength-converting member and the light emitted from the second light source to form a co-axial light beam.

Abstract: Systems including light-emitting diodes (LEDs) are provided. The systems include one or more wavelength-converting member(s) that is/are remote from the emission surface of one or more LED-based light source(s). The wavelength-converting member may be separated from the emission surface of a first LED and positioned such that light emitted from the first LED is absorbed by the wavelength-converting material. The wavelength-converting material emits secondary light having a different wavelength than the wavelength of the light emitted from the first LED. The systems may include a second light source comprising a second LED configured to emit light having a wavelength from an emission surface and a wavelength-combining element configured to combine the secondary light from the wavelength-converting member and the light emitted from the second light source to form a co-axial light beam.

Abstract: A packaged UV-LED device comprises a die carrier member having a cup-shaped recess, a fused silica lens member that is anodic bonded to the die carrier member, and a UV-LED die that is flip-chip mounted within a sealed cavity formed by the carrier member and the lens member. The carrier member involves a unitary cup member fashioned in an economical way from monocrystalline silicon wafer material. A dielectric/aluminum reflector that is effective for UV radiation and that does not degrade and overheat is disposed on the sidewalls of the recess. The lens member is anodic bonded to a silicon surface of the rim of this unitary cup member at a time when the UV-LED die is disposed in the recess. The anodic bonding is done in such way that the die is not damaged and such that the entire packaged UV-LED device includes no UV-degradable adhesive.

Abstract: An LED assembly includes two strings of surface mounted LED devices mounted to a central ceramic plug portion of a PCB substrate. One string has a CCT of 4000 degrees Kelvin. The other has a CCT of 1800 degrees Kelvin. For each LED device in one string there is a corresponding LED device in the other string. The LED devices of each pair are closely spaced with 0.2-0.6 mm between them. A Highly Reflective (HR) layer is disposed on the substrate between the LED devices. The HR layer has a thickness in a range of from 20 to 50 percent H, where H is the height of an LED die. A transparent silicone layer covers the LED devices. A resistor of a warm-dimming circuit is mounted over the ceramic portion of the substrate whereas an integrated circuit portion of the circuit is mounted over the PCB portion of the substrate.

Abstract: Methods and apparatus are provided to improve long-term reliability of LED packages using reflective opaque die attach (DA) material. In one novel aspect, a protected area surrounding edges of the LED is determined. The DA is applied to the determined protected area by a dispense process, a stamping process, or a screen printing process, such that the effect of temperature degradation is reduced. A heat distribution model is used to determine the protected area, which is between edges of the LED and a predefined isothermal line where the temperature is 1/e that of the temperature at edges of the LED. In another embodiment, the protected area is further based on a spreading ratio of the substrate size to the LED size. In another novel aspect, with multiple LEDs in the LED package, the spreading ratio is further based on pitch distances to the immediate adjacent LEDs and the substrate boundary.

Abstract: A light-emitting diode (LED) assembly includes an aluminum substrate, a silver layer, a distributed Bragg reflector (DBR) and an LED device. The aluminum substrate has a top surface whose length and width are each more than once centimeter. The silver layer is disposed over the entire top surface of the aluminum substrate. The DBR is disposed over the entire upper surface of the silver layer. The DBR includes an upper reflector layer and a lower reflector layer. The lower reflector layer contacts the upper surface of the silver layer. The Led device is attached to the upper reflector layer of the DBR, but the LED device is not disposed over the entire upper reflector layer. In one embodiment, the silver layer is deposited on the substrate using physical vapor deposition. In another embodiment, multiple pairs of lower reflector and higher reflector layers are included.

Abstract: Methods and apparatus are provided to improve the yield rate of LED packaging using LED flip chips. In one novel aspect, extended pads made of sintered silver are disposed on the cathode and the anode of the LED flip chip. The thickness of the extended pad is from about 25 ?m to about 200 ?m. In another embodiment, the LED flip chip further comprises a phosphor layer such that the LED flip chip emits white light. In another novel aspect, the LED flip chip with extended pads made of sintered silver is produced at the wafer level. The wafer level process involves applying sintering silver pastes to the cathode and the anode of each LED flip chip formed on the wafer and sintering the wafer at a temperature about 180° C. to about 240° C. for about two hours. The wafer is cut to individual LED flip chips with extended sintered silver pads.

Abstract: Devices and methods including an LED and reflective die attach material are described herein. The devices can include a reflective substrate (e.g., a substrate that includes a silver layer) to which one or more LED die are attached using the die attach material. The die attach material extends beyond the periphery of the LED die to cover an area of the substrate surface.