Philips Lumileds Lighting Company LLC

Lumileds Lighting U.s., LLC

Agilent Technologies, Inc.

Gloria E Hofler

Michael Ragan Krames

Michael David Camras

Douglas W Pocius

Gerd O Mueller

Regina B Mueller-Mach

Frank Michael Steranka

John Julian Uebbing

Troy A Trottier

Robert C Taber

Christopher Haydn Lowery

Wayne L Snyder

Fred A Kish, Jr

Carrie Carter-Coman

Michael James Nystrom

Stephen Andrew Stockman

Nicolas J Moll

Christopher P Kocot

Fred A Kish

Nathan Frederick Gardner

Herman C Chui

Tun-Sein Tan

A device includes a light emitting structure and a wavelength conversion member comprising a semiconductor. The light emitting structure is bonded to the wavelength conversion member. In some embodiments, the light emitting structure is bonded to the wavelength conversion member with an inorganic bonding material. In some embodiments, the light emitting structure is bonded to the wavelength conversion member with a bonding material having an index of refraction greater than 1.5.

Light emitting devices with improved light extraction efficiency

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.

A method of bonding a transparent optical element to a light emitting device having a stack of layers including semiconductor layers comprising an active region is provided. The method includes elevating a temperature of the optical element and the stack and applying a pressure to press the optical element and the stack together. In one embodiment, the method also includes disposing a layer of a transparent bonding material between the stack and the optical element. The bonding method can be applied to a premade optical element or to a block of optical element material which is later formed or shaped into an optical element such as a lens or an optical concentrator.

Method of forming light emitting devices with improved light extraction efficiency

Methods and apparatus for non-contact electrical probes are described. In accordance with the invention, non-contact electrical probes use negative or positive corona discharge. Non-contact electrical probes are suited for testing of OLED flat panel displays.

Method and apparatus for non-contact electrical probe

The extraction efficiency of a light emitting device can be improved by making the absorbing device layers as thin as possible. The internal quantum efficiency decreases as the device layers become thinner. An optimal active layer thickness balances both effects. An AlGaInP LED includes a substrate and device layers including an AlGaInP lower confining layer of a first conductivity type, an AlGaInP active region of a second conductivity type, and an AlGaInP upper confining layer of a second conductivity type. The absorbance of the active region is at least one fifth of the total absorbance in the light-emitting device. The device optionally includes at least one set-back layers of AlGaInP interposing one of confining layer and active region. The p-type upper confining layer may be doped with oxygen improve the reliability.

lll-phosphide light emitting devices with thin active layers

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. Advantageously, this improvement can be achieved without the use of an encapsulant.

Light emitting diodes with improved light extraction efficiency

Provided is a light emitting device including a Fresnel lens and/or a holographic diffuser formed on a surface of a semiconductor light emitter for improved light extraction, and a method for forming such light emitting device. Also provided is a light emitting device including an optical element stamped on a surface for improved light extraction and the stamping method used to form such device. An optical element formed on the surface of a semiconductor light emitter reduces reflective loss and loss due to total internal reflection, thereby improving light extraction efficiency. A Fresnel lens or a holographic diffuser may be formed on a surface by wet chemical etching or dry etching techniques, such as plasma etching, reactive ion etching, and chemically-assisted ion beam etching, optionally in conjunction with a lithographic technique. In addition, a Fresnel lens or a holographic diffuser may be milled, scribed, or ablated into the surface. Stamping, an alternative method for forming an optical element, can also be used to form a Fresnel lens or a holographic diffuser on the surface of a semiconductor light emitter. Stamping includes pressing a stamping block against the surface of a light emitting diode. The stamping block has a shape and pattern that are the inverse of the desired optical element. Optionally, stamping can be done before, after, or concurrently with wafer-bonding. Alternatively, a material can be stamped and later bonded to the semiconductor light emitter.

Forming an optical element on the surface of a light emitting device for improved light extraction

A solderable light-emitting diode (LED) chip and a method of fabricating an LED lamp embodying the LED chip utilize a diffusion barrier that appreciably blocks molecular migration between two different layers of the LED chip during high temperature processes. In the preferred embodiment, the two different layers of the LED chip are a back reflector and a solder layer. The prevention of intermixing of the materials in the back reflector and the solder layer impedes degradation of the back reflector with respect to its ability to reflect light emitted by the LED. The LED chip includes a high power AlInGaP LED or other type of LED, a back reflector, a diffusion barrier and a solder layer. Preferably, the back reflector is composed of silver (Ag) or Ag alloy and the solder layer is made of indium (In), lead (Pb), gold (Au), tin (Sn), or their alloy and eutectics. In a first embodiment, the diffusion layer is made of nickel (Ni) or nickel-vanadium (NiV). In a second embodiment of the invention, the diffusion barrier is made of titanium-tungsten-nitride (TiW:N). In addition to preventing the intermixing of the In of the solder layer with the Ag of the back reflector, the diffusion layer prevents degradation of the Ag reflective properties in the back reflector upon exposure to air. In an alternative embodiment, the diffusion layer is made of a non-conductive material.

Diffusion barrier for increased mirror reflectivity in reflective solderable contacts on high power led chip

Diffusion barrier for increased mirror reflectivity in reflective solderable contacts on high power LED chip

Growing community of inventors

Sunnyvale, CA, United States of America

Gloria E Hofler