Lumileds LLC

Lumileds Singapore Pte. Ltd.

Ken Shimizu

Hisashi Masui

Marcel Rene Bohmer

Daniel Bernardo Roitman

Emma Dohner

Oleg Borisovich Shchekin

Jyoti Kiron Bhardwaj

Frank Jin

Peter Josef Schmidt

Jacques Heuts

Ted Wangensteen

Toni Lopez

Lex Alan Kosowsky

Daniel Estrada

Vernon W Wong

Edward Kang

Ken Davis

Pixelated array light emitters are formed with closely-spaced pixels having ultra-smooth sidewalls. In methods for making such pixelated array light emitters, a converter layer of phosphor particles dispersed in a binder is disposed on a carrier, and then singulated by saw cuts or similar methods to form an array of phosphor pixels. The binder is fully cured prior to singulation of the converter layer. Further, the carrier is rigid rather than flexible. As a consequence of fully curing the binder and of using a rigid carrier to support the converter layer, singulation results in phosphor pixels having smooth side walls. The array of phosphor pixels is subsequently attached to a corresponding array of LEDs with an adhesive layer, separate from the binder used to form the converter layer. The pixel sidewalls may be formed with controlled morphology, for example at acute or obtuse angles with respect to the carrier.

Ultra-smooth sidewall pixelated array LEDs

A method of fabricating closely spaced pcLEDs () arranged in a matrix array () of perpendicular rows and columns comprises an initial phosphor deposition step in which phosphor () is deposited at alternating locations (pixels) in the matrix array in a checkerboard pattern, so that the locations () in the array at which phosphor () is deposited are not adjacent to each other. In a subsequent phosphor deposition step phosphor is deposited at the alternating locations at which phosphor was not deposited in the first deposition step. In between the two phosphor deposition steps, reflective or scattering structures () may be fabricated on sidewalls of the phosphor pixels to optically isolate pcLEDs in the resulting array from each other.

Two step phosphor deposition to make a matrix array

A laterally heterogenous wavelength-converting optical element includes pixel regions surrounded by border regions; each includes down-converting phosphor particles bound by a coating or solid medium. The pixel regions are aligned with LEDs of an array. The phosphor regions differ with respect to one or more of compositions, particle sizes, coating thicknesses, refractive indices, or voids (size, number density, or volume fraction). Those difference(s) can result in the border regions exhibiting larger optical scattering, which can improve contrast of down-converted light emitted by adjacent pixels of the array.

Laterally heterogenous wavelength-converting layer

The pcLED pixels in a phosphor-converted LED array each comprise an optical element on the light-emitting surface above the phosphor layer. In methods for making such pixelated LED arrays, a thin layer of a sacrificial phosphor carrier substrate is retained as the optical element on the output surface of the phosphor pixels upon completion of the fabrication process.

Pixelated LED array with optical elements

Systems for apparatuses formed of light emitting devices. Solutions for controlling the off-state appearance of lighting system designs is disclosed. Thermochromic materials are selected in accordance with a desired off-state of an LED device. The thermochromic materials are applied to a structure that is in a light path of light emitted by the LED device. In the off-state the LED device produces a desired off-state colored appearance. When the LED device is in the on-state, the thermochromic materials heat up and become more and more transparent. The light emitted from the device in its on-state does not suffer from color shifting due to the presence of the thermochromic materials. Furthermore, light emitted from the LED device in its on-state does not suffer from attenuation due to the presence of the thermochromic materials. Techniques to select and position thermochromic materials in or around LED apparatuses are presented.

Controlling off-state appearance of a light emitting device

A distributed Bragg reflector (DBR) structure on a substrate includes a high refractive index layer comprising titanium oxide (TiO) and a low refractive index layer having a high carbon region and at least one low carbon region that contacts the high refractive index layer. Multiple layers of the high refractive index layer and the low refractive index layer are stacked. Typically, the multiple layers of the high refractive index layer and the low refractive index layer are stacked to a thickness of less than 10 microns. Each of the respective layers of the high refractive index layer and the low refractive index layer have a thickness of less than 0.2 microns.

LED DBR structure with reduced photodegradation

A first conversion layer material is formed on unmasked pixel areas of a substrate. Mask material is selectively removed from a second set of pixel areas, leaving a third set of pixel areas masked. A coating is formed on sidewalls of the second pixel areas, and then a second conversion layer material is formed on the second pixel areas and against their sidewalls. Mask material is removed from the third pixel areas, a coating is formed on sidewalls of the third pixel areas, and a third conversion layer material is formed on the third pixel areas and against their sidewalls. The resulting wavelength-conversion layer includes contiguously arranged regions of the first, second, and third conversion layer materials, at least two of which are wavelength-converting phosphor materials. The sidewall coatings between the regions act as barriers to lateral light transmission.

Pixelated wavelength-conversion layer

Pixelated array light emitters are formed with closely-spaced pixels having ultra-smooth sidewalk. In methods for making such pixelated array light emitters, a converter layer of phosphor particles dispersed in a binder is disposed on a carrier, and then singulated by saw cuts or similar methods to form an array of phosphor pixels. The binder is fully cured prior to singulation of the converter layer. Further, the carrier is rigid rather than flexible. As a consequence of fully curing the binder and of using a rigid carrier to support the converter layer, singulation results in phosphor pixels having smooth side walls. The array of phosphor pixels is subsequently attached to a corresponding array of LEDs with an adhesive layer, separate from the binder used to form the converter layer. The pixel sidewalls may be formed with controlled morphology, for example at acute or obtuse angles with respect to the carrier.

A semiconductor light emitting device (B,C;) may have a reflective side coating () disposed on a sidewall () of a semiconductor light emitting device structure. Such a device may be fabricated by dicing a semiconductor structure to separate a semiconductor light emitting device structure and then forming a reflective side coating () on a sidewall () of the separated semiconductor light emitting device structure.

Semiconductor light emitting device with reflective side coating

A method of fabricating closely spaced pcLEDs arranged in a matrix array of perpendicular rows and columns comprises an initial phosphor deposition step in which phosphor is deposited at alternating locations (pixels) in the matrix array in a checkerboard pattern, so that the locations in the array at which phosphor is deposited are not adjacent to each other. In a subsequent phosphor deposition step phosphor is deposited at the alternating locations at which phosphor was not deposited in the first deposition step. In between the two phosphor deposition steps, reflective or scattering structures may be fabricated on sidewalls of the phosphor pixels to optically isolate pcLEDs in the resulting array from each other.

A distributed Bragg reflector (DBR) structure on a substrate includes a high refractive index layer comprising titanium oxide (TiO2) and a low refractive index layer having a high carbon region and at least one low carbon region that contacts the high refractive index layer. Multiple layers of the high refractive index layer and the low refractive index layer are stacked. Typically, the multiple layers of the high refractive index layer and the low refractive index layer are stacked to a thickness of less than 10 microns. Each of the respective layers of the high refractive index layer and the low refractive index layer have a thickness of less than 0.2 microns.

A light emitting package and method of making the package are described. The package contains an LED bonded to a light converting layer using an adhesive. The adhesive is jet printed, mask sprayed or extruded onto one of the surfaces before bonding. The adhesive has materials in different sections that differ in refractive index, oxygen permeability, and/or heat conductivity. The materials are formed in concentric rings around the adhesive center, islands or lines and are disposed to provide optical lensing or increasing permeability/heat conductivity with decreasing distance from the center. A substantially-reflective optical side coat surrounds the LED, adhesive layer and connecting structure.

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Sunnyvale, CA, United States of America

Ken Shimizu