US20020176259A1

US20020176259A1 - Systems and methods for converting illumination

Info

Publication number: US20020176259A1
Application number: US10/113,834
Authority: US
Inventors: Alfred Ducharme
Original assignee: Color Kinetics Inc
Current assignee: Signify North America Corp
Priority date: 1999-11-18
Filing date: 2002-04-01
Publication date: 2002-11-28
Also published as: US7132785B2; US20070047227A1; US8142051B2; US20050041424A1

Abstract

An illumination system according to the principles of the invention may include a first LED and a carrier material. The carrier material may be comprised of plastic, synthetic material, polymer, latex, rubber or other material. The carrier material may also contain a phosphor, fluorescent material, organic fluorescent material, inorganic fluorescent material, impregnated phosphor, phosphor particles, phosphor material, YAG:Ce phosphor, or other material for converting electromagnetic radiation into illumination or visible light. The illumination system may also have a housing wherein the housing has an open end. The first LED may be arranged to project emitted light through the open end and the carrier material may be cooperatively arranged with the housing such that the emitted light from the first LED is projected through the carrier material.

Description

CROSS REFERENCES TO RELATED APPLICATIONS [0001]
This application claims the benefit, under 35 U.S.C. §119(e), of U.S. provisional application Ser. No. 60/280,215, filed Mar. 30, 2001, entitled “Systems and Methods for Converting Illumination. This application also claims the benefit, under 35 U.S.C. §120, as a continuation-in-part (CIP) of U.S. non-provisional patent application Ser. No. 09/716,819, filed Nov. 20, 2000, entitled “Systems and Methods for Generating and Modulating Illumination Conditions.” This application also claims the benefit, under 35 U.S.C. §120, of the following U.S. provisional applications, as the above-identified U.S. non-provisional application similarly is entitled to the benefit of the following applications: [0002]
Ser. No. 60/166,533, filed Nov. 18, 1999, entitled “Designing Lights With LED Spectrum; [0003]
Ser. No. 60/235,678, filed Sep. 27, 2000, entitled “Ultraviolet Light Emitting Diode Device; and [0004]
Ser. No. 60/201,140, filed May 2, 2000, entitled “Systems and Methods for Modulating Illumination Conditions. [0005]
Each of the foregoing applications hereby is incorporated herein by reference.[0006]

BACKGROUND

1. Field of the Invention

The present invention relates to light emitting diode devices. In particular the invention relates to illumination systems using LEDs along with various materials to convert the light emitted from the LEDs.

2. Description of Related Art

Light emitting diodes (LEDs) are becoming a viable alternative to conventional light sources in many applications. For years, LEDs were used as indicator lights because of their long life, reliability and energy efficiency. Most recently, LEDs have been making a big impact in the field of illumination. LEDs have been exponentially increasing in brightness over the years, leading to their acceptance into the field of illumination.

While many LEDs provide nearly 100,000 hours of performance, white LEDs have significantly shorter lives. Both the expected lifetime and the lumen maintenance over the lifetime are significantly reduced compared to conventional non-white high-brightness LEDs. There may be several reasons for this drop-off in performance. The white LED package uses a blue or ultraviolet die to pump an active phosphor impregnated in the die, package or epoxy used in the package of the LED to produce white light. The phosphor converts the blue or ultraviolet wavelengths produced by the die into a white light. The die itself usually produces a rather narrow spectrum of blue light and the phosphor down converts this energy to longer wavelength energy. The resulting spectrum is shifted from the narrow blue towards the middle of the visible spectrum and the spectrum is typically broadened. White LEDs are available through companies such as Nichia. Because of imperfections in this down conversion, the white LEDs produce a very blue-white light meaning the color temperature of the illumination and the quality of the light is not acceptable for many general illumination applications.

SUMMARY OF THE INVENTION

In various embodiments, methods and systems are provided for improved white light LED systems. In an embodiment, the present invention is an apparatus for providing an efficient, computer-controlled, multicolored illumination network capable of high performance and rapid color selection and change.

An embodiment of an illumination system may include a first LED and a carrier material. The carrier material may be comprised of plastic, synthetic material, polymer, latex, rubber or other material. The carrier material includes a phosphor, fluorescent material, organic fluorescent material, inorganic fluorescent material, impregnated phosphor, phosphor particles, phosphor material, YAG:Ce phosphor, or other material which can convert electromagnetic radiation into illumination and/or visible light. The illumination system may also have a housing wherein the housing has an open end. The first LED may be arranged to project emitted light through the open end and the carrier material may be cooperatively arranged with the housing such that the emitted light from the first LED is projected through the carrier material.

Another embodiment of an illumination system may include a first LED and a carrier material. The carrier material may be comprised of plastic, synthetic material, polymer, latex, rubber or other material. The carrier material may also contain a phosphor, fluorescent material, organic fluorescent material, inorganic fluorescent material, impregnated phosphor, phosphor particles, phosphor material, YAG:Ce phosphor, or other material which can convert electromagnetic radiation into illumination and/or visible light. The illumination system may also include a housing wherein the housing may be made of a transparent material, translucent material, semi-transparent material, semi-translucent material or other material capable of at least partial transmission of electromagnetic radiation. The LED may be arranged to project emitted light through the housing. The carrier material may be cooperatively arranged with the housing such that the emitted light from the first LED is projected through the material.

Another embodiment of an illumination system may include a first LED and a housing. The housing may be formed from a carrier material; wherein the material comprises plastic, synthetic, polymer, latex, rubber or other material. The carrier material may further comprise a phosphor, fluorescent material, organic fluorescent material, inorganic fluorescent material, impregnated phosphor, phosphor particles, phosphor material, YAG:Ce phosphor, or other material which can convert electromagnetic radiation into illumination and/or visible light. The LEDs may be arranged to project emitted light through the housing.

Another embodiment of an illumination system may include a second LED wherein the second LED produces a different spectral distribution from the first LED. The second LED may produce amber light, yellow light, red light, or any other light or electromagnetic radiation.

Yet another embodiment of an illumination system may include two different colored LEDs and a housing. The housing may comprise a transparent material, translucent material, semi-transparent material, semi-translucent material, or other material capable of at least partial transmission of electromagnetic radiation. The two different colored LEDs may be arranged to project light through the housing. A carrier material comprising plastic, synthetic, polymer, latex, rubber or other material may be associated with the housing. The carrier material may further comprise a phosphor. fluorescent material, organic fluorescent material, inorganic fluorescent material, impregnated phosphor, phosphor particles, phosphor material, YAG:Ce phosphor or other material which can convert electromagnetic radiation into illumination and/or visible light. The first material may be selectively arranged in cooperation with the housing such that the light produced by one of the two LEDs is projected through the carrier material and light produced by one of the two LEDs is projected from the illumination system without passing through the carrier material.

At least one of the two LEDs in an embodiment may produce blue light, violet light, ultraviolet light or other light or electromagnetic radiation. At least one of the two LEDs in an embodiment may produce amber light, yellow light, red light or other light.

In an embodiment, one of the LEDs may produce short-wavelength light. The short-wavelength LED produces may produce blue light, violet light, ultraviolet light or other short-wavelength light. The carrier material may be selectively arranged in strips such that the light from the short-wavelength LED is projected through the first material.

The carrier material may alternatively be selectively arranged as a continuous sheet with holes such that the light from the short-wavelength LED is projected through the carrier material.

The system may comprise a first carrier material and a second material. The first carrier material may be comprised of plastic, synthetic, polymer, latex, rubber or other material. The first material may further comprise a phosphor, fluorescent material, organic fluorescent material, inorganic fluorescent material, impregnated phosphor, phosphor particles, phosphor material, YAG:Ce phosphor or other material which can convert electromagnetic radiation into illumination and/or visible light. The second carrier material may be comprised of plastic, synthetic, polymer, latex, rubber or other material. The second material may further comprise a phosphor, fluorescent material, organic fluorescent material, inorganic fluorescent material, impregnated phosphor, phosphor particles, phosphor material, YAG:Ce phosphor or other material which can convert electromagnetic radiation into illumination and/or visible light. The second carrier material may be different than the first carrier material. The first carrier material may be selectively arranged such that the light from at least one of the short-wavelength LED is projected through the first carrier material; and wherein the second carrier material may be selectively arranged such that the light from the short-wavelength LED is projected through the second carrier material.

In any of the above embodiments the first LED may emit blue light, violet light, ultraviolet light or other light. The first LED may emit a peak wavelength of approximately 480 nm in one embodiment or any wavelength(s) less than 550 nm in another embodiment. In an embodiment of the invention, the housing may form a reflector housing, linear lamp housing, cove housing, MR16 housing, C-Series housing, ColorBlast housing, a lighting fixture housing, or other housing. Some housings which may be used are described in U.S. patent app. Ser. No. 09/669,121 for “Multicolored LED Lighting Method and Apparatus,” U.S. patent app. Ser. No. 60/235,966 for “Optical System for Light-Emitting Semiconductors,” U.S. patent application Ser. No. 09/333,739 for “Diffuse Illumination Systems and Methods,” U.S. patent app. Ser. No. 29/138,407 for “Lighting Fixture,” U.S. patent app. Ser. No. 09/215,624 for “Smart Light Bulb,” and U.S. patent app. Ser. No. 09/805,368 for “Light-emitting Diode based products.” The entire disclosures of each of these applications is incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures depict certain illustrative embodiments of the invention which like reference numerals refer to like elements. These depicted embodiments arc be understood as illustrative of the invention and not as limiting in any way. [0023]
FIG. 1 depicts an exemplary lighting system; [0024]
FIG. 2 illustrates an embodiment of an illumination system; [0025]
FIG. 3 shows an embodiment of an illumination system with alternative sectional views; [0026]
FIGS. 3A, 3B, [0027] 3C, and 3D show cross sectional view of the embodiment of FIG. 3 at the line A-A;
FIG. 4 depicts an embodiment of an illumination system with selectively arranged material; [0028]
FIG. 5 illustrates an embodiment of an illumination system with selectively arranged material; [0029]
FIG. 6 illustrates an embodiment of an illumination system with two different types of material; and [0030]
FIG. 7 shows another embodiment of an illumination system.[0031]

DETAILED DESCRIPTION

The description below pertains to several illustrative embodiments of the invention. Although many variations of the invention may be envisioned by one skilled in the art, such variations and improvements are intended to fall within the compass of this disclosure. Thus, the scope of the invention is not to be limited in any way by the disclosure below. [0032]
As used herein, the term “LED” means any system that is capable of receiving electrical signal and producing a color of light in response to the signal. Thus, the term “LED” should be understood to include light emitting diodes of all types, light emitting polymers, semiconductor dies that produce light in response to current, organic LEDs, electro-luminescent strips, and other such systems. In an embodiment, an “LED” may refer to a single light emitting diode having multiple semiconductor dies that are individually controlled. It should also be understood that the term “LED” does not restrict the package type of the LED. The term “LED” includes packaged LEDs, non-packaged LEDs, surface mount LEDs, chip on board LEDs and LEDs of all other configurations. The term “LED” also includes LEDs packaged or associated with phosphor wherein the phosphor may convert energy from the LED to a different wavelength. [0033]
An LED system is one type of illumination source. As used herein “illumination source” should be understood to include all illumination and/or light sources, including LED systems, as well as incandescent sources, including filament lamps, pyro-luminescent sources, such as flames, candle-luminescent sources, such as gas mantles and carbon arch radiation sources, as well as photo-luminescent sources, including gaseous discharges, fluorescent sources, phosphorescence sources, lasers, electro-luminescent sources, such as electro-luminescent lamps, light emitting diodes, and cathode luminescent sources using electronic satiation, as well as miscellaneous luminescent sources including galvano-luminescent sources, crystallo-luminescent sources, kine-luminescent sources, thermo-luminescent sources, triboluminescent sources, sonoluminescent sources, and radioluminescent sources. Illumination sources may also include luminescent polymers capable of producing primary colors. [0034]
The term “illuminate” should be understood to refer to the production of a frequency of radiation by an illumination source. The term “color” should be understood to refer to any frequency of radiation within a spectrum; that is, a “color,” as used herein, should be understood to encompass a frequency or combination of frequencies not only of the visible spectrum, but also frequencies in the infrared and ultraviolet areas of the spectrum, and in other areas of the electromagnetic spectrum. [0035]
There have been significant advances in the control of LEDs. U.S. patents in the field of LED control include U.S. Pat. Nos. 6,016,038, 6,150,774, and 6,166,496. U.S. patent application Ser. No. 09/716,819 for “Systems and Methods for Generating and Modulating Illumination Conditions” also describes, among other things, systems and controls. The entire disclosure of all these documents is herein incorporated by reference. [0036]
One embodiment of U.S. patent application Ser. No. 09/716,819 teaches of combining white LEDs with LEDs of different colors to produce a high quality white light with acceptable and/or alterable color temperature. One embodiment also teaches of modulating the power to at least one of the LEDs in the illumination system for controlling the color temperature of the light. This can, for example, be useful for modulating the illumination conditions within a room. This could be used to change the color temperature in a room from a warm sunrise color in the morning through a cooler noon-time color and back to an evening sunset condition. [0037]
FIG. 1 illustrates a block diagram of one embodiment of an [0038] illumination system 100. A processor 2 is associated with several controllers 3. The controllers 3 control the power to the LEDs 4. As used herein, the term processor may refer to any system for processing electronic signals. A processor may include a microprocessor, microcontroller, programmable digital signal processor, other programmable device, a controller, addressable controller, microprocessor, microcontroller, addressable microprocessor, computer, programmable processor, programmable controller, dedicated Processor, dedicated controller, integrated circuit, control circuit or other processor. A processor may also, or instead, include an application specific integrated circuit, a programmable gate array, programmable array logic, a programmable logic device, a digital signal processor, an analog-to-digital converter, a digital-to-analog converter, or any other device that may be configured to process electronic signals. In addition, a processor may include discrete circuitry such as passive or active analog components including resistors, capacitors, inductors, transistors, operational amplifiers, and so forth, as well as discrete digital components such as logic components, shift registers, latches, or any other separately packaged chip or other component for realizing a digital function. Any combination of the above circuits and components, whether packaged discretely, as a chip, as a chipset, or as a die, may be suitably adapted to use as a processor as described herein. It will further be appreciated that the term processor may apply to an integrated system, such as a personal computer, network server, or other system that may operate autonomously or in response to commands to process electronic signals such as those described herein. Where a processor includes a programmable device such as the microprocessor or microcontroller mentioned above, the processor may further include computer executable code that controls operation of the programmable device. In an embodiment, the processor 2 is Microchip PIC processor 12C672 and the LEDs 4 may be red, green and blue.
The [0039] controller 3 may be a pulse width modulator, pulse amplitude modulator, pulse displacement modulator, resistor ladder, current source, voltage source, voltage ladder, switch, transistor, voltage controller, or other controller. The controller controls the current, voltage or power through the LED 4. The controller also has a signal input wherein the controller is responsive to a signal received by the signal input. The signal input is associated with the processor such that the processor communicates signals to the signal input and the controller regulates the current, voltage and or power through the LED. In an embodiment, several LEDs with different spectral output may be used. Each of these colors may be driven through separate controllers. The processor and controller may be incorporated into one device. This device may power capabilities to drive several LEDs in a string or it may only be able to support one or a few LEDs directly. The processor and controller may also be separate devices. By controlling the LEDs independently, color mixing can be achieved for the creation of lighting effects. In an embodiment, memory 6 is also be provided. The memory 6 is capable of storing algorithms, tables, or values associated with the control signals. The memory 6 may store programs for controlling the LEDs 4. The memory may be memory, read-only memory, programmable memory, programmable read-only memory, electronically erasable programmable read-only memory, random access memory, dynamic random access memory, double data rate random access memory, Rambus direct random access memory, flash memory, or any other volatile or non-volatile memory for storing program instructions, program data, address information, and program output or other intermediate or final results. A program, for example, may store control signals to operate several different colored LEDs 4. A user interface I may also be associated with the processor 2. The user interface may be used to select a program from memory, modify a program from memory, modify a program parameter from memory, select an external signal or provide other user interface solutions. Several methods of color mixing and pulse width modulation control are disclosed in U.S. Pat. No. 6,016,038 “Multicolored LED Lighting Method and Apparatus,” the entire disclosure of which is incorporated by reference herein. The processor 2 can also be addressable to receive programming signals addressed to it.
Another useful interface is an interface that is associated with a power source. An energy storage element can be associated with a power source. The energy storage device cart also be associated with a processor. The energy storage element may be a capacitor, non-volatile memory, battery backed memory, relay, storage device or other energy storage element. The element may communicate a logic high and a logic low signal to the processor depending on the state of the element. For example, the element may communicate a low logic signal when the device is connected to the power source and a high logic signal when the device is disconnected from the power source. The high logic signal may change to a low logic signal following a predetermined period of time and the processor may be monitoring the signal. The lighting device could be programmed such that a last lighting program may be operating when the device is de-energized. If the device is re-energized within a predetermined period, while the logic signal is still high, the device may select a new program from memory to execute. If the device is not re-energized within the predetermined period, the device may start up in the last lighting program or a default program or vice-versa. A non-volatile memory, battery backed memory or other memory may be provided such that the last program is remembered. The technique can be used to change the program, a program parameter or other setting. This technique can be used in a device that does not include a separate user interface by turning the power to the lighting device off and on. A separate switch could also be employed to provide the user interface as well as an on/off switch. [0040]
As used herein the term “convert” shall mean a process method, or similar thing that changes the properties of the electromagnetic radiation generated by illumination source. This process may also be generally referred to as down converting. This process is generally used to describe an active phosphor as in a fluorescent lamp for example. The phosphor coating on a fluorescent lamp converts (or down converts) the ultraviolet energy produced by the mercury discharge into visible light. Different phosphors can be combined into one mixture such that several different conversion processes occur simultaneously. Many fluorescent lamps use three phosphors or a tri-phosphor to convert the ultraviolet light into three different spectral power distributions. This conversion generally results in the ultraviolet light appearing as “white light” in the visible spectrum. Converting within this disclosure can be from any wavelength(s) of electromagnetic radiation into any other wavelength(s) of electromagnetic radiation including the same wavelength(s). [0041]
An [0042] illumination system 200 according to the principles of the invention may include a carrier material 204. The system 200 may also include a system 100 with one or more LEDs 4. The carrier material 204 may be arranged such that illumination from an LED 4 is projected through the carrier material 204. The carrier material is designed to convert the light received into a different spectral power distribution. The LED spectral power distribution may be narrow and the carrier material 204 may be used to AR the spectra and/or broaden the spectral power distribution or otherwise change the spectral power distribution. The carrier material 204 may be made of plastic, synthetic material, polymer, latex, rubber or other material. The carrier material 204 may also be comprised of a phosphor, fluorescent material, organic fluorescent material, inorganic fluorescent material, impregnated phosphor, phosphor particles, phosphor material, YAG:Ce phosphor, or other material to convert the electromagnetic radiation projected from the LED or other illumination source into illumination and/or visible light. Combinations of the above carrier material 204 or material to convert are also included an embodiment of the invention. One possible carrier material with these properties can be purchased from ARI International, 2015 S. Arlington Heights, Ill. 60005. ARI International has a rubber-based product referred to as White Cap. ARI International offers several different materials to convert the light from a blue LED into several different colors.
The illumination system may also comprise a [0043] housing 202. The housing 202 may be designed to house the LED system 100. The carrier material 204 may be cooperatively arranged with the housing such that the illumination from at least one of the LEDs passes through the carrier material 204. FIG. 2 illustrates a configuration according to the principles of the invention where the carrier material 204 is placed over the exit aperture or open end 208 of the housing. FIG. 7 illustrates another configuration according to the principles of the invention where the carrier material 204 is placed over the inlet to the reflector. The carrier material 204 can be arranged in any position such that the illumination from any of the LEDs passes through the carrier material.
FIGS. 3, 3A, [0044] 3B, 3C, and 3D illustrate another configuration of an illumination system according to the principles of the invention. This system includes a housing 202 wherein the LEDs 4 are substantially contained. In this configuration, the LED illumination is projected through the housing 202. The housing 202 may be made of a transparent material, translucent material, semi-transparent material, semi-translucent material, or other material designed to allow for the transmission or partial transmission of electromagnetic radiation. A carrier material 204 may be cooperatively associated with the housing 202 such that the electromagnetic radiation emitted from at least one of the LEDs passes through the carrier material 204. For example, FIG. 3A shows the carrier material 204 enclosing the housing 202. FIG. 3B shows a system where the carrier material 204 is selectively arranged to cover a portion of the housing. FIG. 3C shows another alternative example where the housing 202 is formed of the carrier material 202. FIG. 3D shows the carrier material selectively arranged to cover a portion of the housing. With this arrangement, some of the light from an LED may be converted while some of the light from the LED may not be converted.
FIG. 4 illustrates another exemplary illumination system where the [0045] carrier material 204 is selectively arranged. The carrier material 204 may cover or be formed in sections of the housing while not covering other sections. For instance, “holes” or openings may be left in the carrier material 204 to reveal housing 202 or so that there is no carrier material at the “hole.” This arrangement may be designed to allow the carrier material 204 to cover certain LEDs while allowing other LEDs to project light without passing through the carrier material. A useful example of this arrangement could be where at least two different colored LEDs are provided in the illumination system. The LEDs may be alternating blue and amber for example. The blue LEDs may be arranged to project illumination through the carrier material 204 and the amber LEDs may be arranged to project illumination through the housing 202 and/or hole without passing through the carrier material 204. This arrangement could be useful for producing a different color temperature light or variable color temperature light or other lighting effects. U.S. patent application Ser. No. 09/716,819 describes some methods of modulating illumination conditions which could be used for such radiation and the entire disclosure is hereby incorporated by reference herein. The system could be controlled such that the intensity of each of the colors within the system could be modulated to change the illumination conditions produced by the system. For example, the blue LED may be driven at a high level and the amber LED power may be varied. The light projected from the several LEDs combines and this technique can be used to change the overall color of the system. In this example, the carrier material 204 is used to convert the blue LED radiation to white radiation and the amber LED is used to lower the color temperature of the resultant radiation. It will be obvious to one of ordinary skill in the art that there are many combinations of LEDs that could be used to produce useful colors, illumination, and changing illumination effects. Some of these are also disclosed in the above referenced U.S. patent application Ser. No. 09/716,819.
Another configuration of a system according to the principles of the invention is illustrated in FIG. 5. The [0046] carrier material 204 is selectively arranged in strips to cover portions of the housing. The strips may be arranged such that the illumination from at least one of the LEDs is projected through the carrier material 204.
Another useful embodiment according to the principles of the invention is depicted in FIG. 6. In this example, the illumination system is using at two or more different types of carrier material [0047] 201 The LEDs 4 may produce the same color or they may be different colors. Providing a system with one or more LEDs of the same color can be useful. For example, if a blue LED is provided along with two different carrier materials, the light projected through the two different carrier materials will produce two different colors. One carrier material may produce a high color temperature white light while the other carrier material produces a low color temperature white light. The illumination from the system would produce a combined color temperature from the two carrier materials and allow for control over the color temperature. A system with two blue LEDs, for example, along with two different types of material may be useful for producing a combined color from the system. The illumination conditions could also be adjusted by modulating the power of the separate LEDs. Through this modulation, the light emitted through one or more of the carrier materials can be changed to change the overall color emitted from the system.
In yet another embodiment of the invention, illumination systems having three or more colors of LEDs could be generated with any number of these LEDs having their illumination converted by one or more types of [0048] carrier material 204. The principles of building such a system extend from the above examples and would be understood by one of skill in the art.
In another configuration there can be partitions, reflectors or other dividers separating LEDs so that light from any single LED can be directed at a particular location such as [0049] carrier material 204, housing 202 or a hole while limiting spill from the LED into the other locations.
All articles, patents, and other references set forth above are hereby incorporated by reference. While the invention has been disclosed in connection with the embodiments shown and described in detail, various equivalents, modifications, and improvements will be apparent to one of ordinary skill in the art from the above description. Such equivalents, modifications, and improvements are encompassed herein. [0050]

Claims

1. An illumination system comprising:

at least one LED;

a conversion material comprising at least one of a plastic, a synthetic material, a polymer, latex, rubber, a phosphor, a fluorescent material, an organic fluorescent material, an inorganic fluorescent material, an impregnated phosphor, phosphor particles, a phosphor material, and a YAG:Ce phosphor; and

a housing having an open end,

wherein:

the at least one LED is arranged to project emitted light through the open end of the housing; and

the conversion material is cooperatively arranged with the housing such that the emitted light from the at least one LED is projected through the material.