LED illuminator apparatus, using multiple luminescent materials dispensed onto an array of LEDs, for improved color rendering, color mixing, and color temperature control

• US 9,133,990 B2
• Filed: 01/31/2013
• Issued: 09/15/2015
• Est. Priority Date: 01/31/2013
• Status: Active Grant

• Current Assignee: DiCon Fiber Optics Incorporated
• Original Assignee: DiCon Fiber Optics Incorporated
• Inventors: Lee, Ho-Shang, Chiang, Brian I-Yuan, Lu, Junying Jonathan, Schleicher, Robert Eric
• Primary Examiner(s): VO, TUYET THI
• Application Number:
  US13/756,282
• Publication Number:
  US 20140210368A1
• Time in Patent Office: 957 Days
• Field of Search: 315/247, 315/224, 315/225, 315/185.S, 315/291, 315307-326, 362/84, 362/230, 362231-233, 362/601, 362608-613
• US Class Current: 1/1
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21V 29/67 characterised by the arrangement of fans
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2105/12 characterised by the geometrical disposition of the light-generating elements, e.g. arranging light-generating elements in differing patterns or densities
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H05B 45/20 Controlling the colour of the light

Abstract

An LED array includes three or more strings of bare LEDs mounted in close proximity to each other on a substrate. The strings of LEDs emit light of one or more wavelengths of blue, indigo and/or violet light, with peak wavelengths that are less than 490 nm. Luminescent materials deposited on each of the LED chips in the array emit light of different wavelength ranges that are of longer wavelengths than and in response to light emissions from the LED chips. A control circuit applies currents to the strings of LEDs, causing the LEDs in the strings to emit light, which causes the luminescent materials to emit light. A user interface enables users to control the currents applied by the control circuit to the strings of LEDs to achieve a Correlated Color Temperature (CCT) value and hue that are desired by users, with CIE chromaticity coordinates that lie on, or near to the black body radiation curve. Preferably a transparent material is dispensed on the substrate between the LED semiconductor chips to substantially surround the LED semiconductor chips. Thereafter at least one layer containing luminescent materials is applied on the LED semiconductor chips and the transparent material.

Claims

1. An illumination apparatus, comprising:

an LED array, said array including three or more strings of LEDs, wherein said strings of LEDs emit light of one or more wavelengths of blue, indigo and/or violet light, with peak wavelengths that are less than 490 nm;

said LED array comprising bare LED chips that are mounted in close proximity to each other on a substrate;

luminescent materials that are deposited on each of the LED chips in the array, said materials emitting light of different wavelength ranges that are of longer wavelengths than said light emissions from the LED chips, with the emissions from the luminescent materials being in response to such light emissions from the LED chips;

a control circuit that applies currents to the strings of LEDs, causing the LEDs in the strings to emit light, which causes the luminescent materials to emit light; and

a user interface that enables users to control the currents applied by the control circuit to the strings of LEDs to achieve a Correlated Color Temperature (CCT) value and hue that are desired by users, with CIE chromaticity coordinates that lie on, or near to the black body radiation curve, wherein the different peak wavelengths of the LEDs in the array are arranged symmetrically about two orthogonal axes, and about two diagonal axes at 45 degrees to the two orthogonal axes, so that for each peak wavelength of LEDs in the array, there are equal quantities of LEDs with such peak wavelength on both sides of each of the four axes.

2. An illumination apparatus, comprising:

an LED array, said array including three or more strings of LEDs, wherein said strings of LEDs emit light of one or more wavelengths of blue, indigo and/or violet light, with peak wavelengths that are less than 490 nm;

said LED array comprising bare LED chips that are mounted in close proximity to each other on a substrate;

luminescent materials that are deposited on each of the LED chips in the array, said materials emitting light of different wavelength ranges that are of longer wavelengths than said light emissions from the LED chips, with the emissions from the luminescent materials being in response to such light emissions from the LED chips;

a control circuit that applies currents to the strings of LEDs, causing the LEDs in the strings to emit light, which causes the luminescent materials to emit light; and

a user interface that enables users to control the currents applied by the control circuit to the strings of LEDs to achieve a Correlated Color Temperature (CCT) value and hue that are desired by users, with CIE chromaticity coordinates that lie on, or near to the black body radiation curve, wherein the different luminescent materials with different emissions spectra are arranged symmetrically about two orthogonal axes, and about two diagonal axes at 45 degrees to the two orthogonal axes, so that for each type of luminescent material with a particular emissions spectrum, there are equal quantities of LED chips with such luminescent material deposited on said LED chips, on both sides of each of the four axes.

3. An illumination apparatus, comprising:

an LED array, said array including three or more strings of LEDs, each of said strings comprising multiple LEDs, wherein said strings of LEDs emit light of one or more wavelengths of blue, indigo and/or violet light, with peak wavelengths that are less than 490 nm;

said LED array comprising bare LED chips that are mounted in close proximity to each other on a substrate;

luminescent materials that are deposited on each of the LED chips in the array, said materials emitting light of different wavelength ranges that are of longer wavelengths than said light emissions from the LED chips, with the emissions from the luminescent materials being in response to such light emissions from the LED chips;

a control circuit that applies currents to the strings of LEDs, causing the LEDs in the strings to emit light, which causes the luminescent materials to emit light; and

a user interface that enables users to control the currents applied by the control circuit to the strings of LEDs to achieve a Correlated Color Temperature (CCT) value and hue that are desired by users, with CIE chromaticity coordinates that lie on, or near to the black body radiation curve, said LED array having a center and two orthogonal axes wherein the different strings of LEDs are arranged or configured as symmetric pairs, with respect to the center of the LED array, and wherein the LED chip locations of each LED string are arranged or configured symmetrically around one of the two orthogonal axes of the LED array.