Multicolor illumination device using moving plate with wavelength conversion materials
A multicolor illumination device using an excitation light source and a multi-segmented moving plate with wavelength conversion materials (e.g. phosphors) is disclosed. The exciting light source is a light emitting diode or a laser diode emitting in the UV and/or blue region. The wavelength conversion materials absorb the excitation light and emit longer wavelength light. Each segment of the moving plate contains a different wavelength conversion material or no wavelength conversion material. The plate is supported to move so that different segments are exposed to the excitation light at different times. The plate may be a wheel or rectangular in shape and rotates or oscillates linearly. When the plate moves, light of different colors is generated sequentially in time by the different wavelength conversion materials in different segments of the plate. The multicolor illumination device may be used in a projector system having a microdisplay imager for image display.
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The present application is a reissue of U.S. Pat. No. 7,547,114. More than one reissue application has been filed for the reissue of U.S. Pat. No. 7,547,114. The reissue applications are U.S. application Ser. Nos. 15/088,548 (the present application) and 15/365,871, both of which are reissues of U.S. Pat. No. 7,547,114. U.S. application Ser. No. 15/365,871 is a continuation reissue of U.S. application Ser. No. 15/088,548 (the present application).
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention relates to lighting devices and systems, and in particular, it relates to devices for generating high brightness multicolor light using wavelength conversion.
2. Description of the Related Art
Wavelength conversion methods that use excitation light produced by solid-state light source such as laser diodes (LDs) or light emitting diodes (LEDs) and wavelength conversion materials such as phosphors or quantum dots can produce high brightness light at wavelengths different from the wavelength of the excitation light. In conventional devices, excitation light impinges on a wavelength conversion material, which absorbs the excitation light and emits light at a wavelength higher than the wavelength of the excitation light. To generate light of different colors, different wavelength conversion materials are typically employed. In a projection system described in commonly owned International Patent Application Publication No. WO 2006/102846 A1 published Oct. 5, 2006, three LED light sources are used to generate red, green and blue light, respectively (see
In some conventional multicolor illumination devices, a white light source (such as a high pressure mercury lamp) is used in conjunction with a color wheel to generate color lights with controlled time sequences. The color wheel, which is disposed in front of the white light source, is made of multiple color filters each transmitting light of a particular color.
SUMMARY OF THE INVENTIONThe present invention is directed to an illumination device for generating multicolor light using wavelength conversion, which includes an excitation light source and a multiple wavelength conversion materials on a moving plate. By using Etendue conserved focusing optics, multicolor light having high power and high brightness is obtained. The illumination device may be used for image projection systems.
An object of the present invention is to provide a high power and high brightness multicolor illumination device.
Additional features and advantages of the invention will be set forth in the descriptions that follow and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the present invention provides an illumination device for providing multicolor light, which includes: a light source for generating an excitation light; and a moving plate including two or more segments, wherein one or more of the segments each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light, wherein a first segment contains a first wavelength conversion material, and a second segment either contains a different wavelength conversion material or contains no wavelength conversion material, wherein a part of the moving plate is disposed on an optical path of the excitation light, and wherein the moving plate is supported to move so that different segments are exposed to the excitation light at different times. The illumination device may optionally include focusing optics and coupling optics disposed between the light source and the moving plate, a dichroic filter disposed between the wavelength conversion material and the light source, an angle-selective reflecting layer located adjacent the wavelength conversion material on a side opposite to the light source, a reflector cup with an exit aperture disposed adjacent the wavelength conversion material, and/or a reflective polarizer and a waveplate disposed adjacent the wavelength conversion material.
In another aspect, the present invention provides a method for generating multicolor light, which includes: generating an excitation light using a light source; directing the excitation light onto a segment of a moving plate, the moving plate having two or more segments, wherein one or more of the segments each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light, wherein a first segment contains a first wavelength conversion material, and a second segment either contains a different wavelength conversion material or contains no wavelength conversion material; and moving the moving plate so that different segments are exposed to the excitation light at different times to generate emitted light of different colors.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
Embodiments of the present invention provide a multicolor illumination device using an excitation light source and a multi-segmented moving plate with wavelength conversion materials, i.e., a plate having segments each containing a different wavelength conversion material (or no wavelength conversion material), where the plate is supported to move so that different segments are exposed to the excitation light at different times. The movement may be a rotation or a linear oscillation. When the moving plate moves, light of different colors is generated sequentially in time by the different wavelength conversion materials in different segments of the moving plate. The illumination device also includes focusing optics and a dichroic filter that passes shorter wavelength light and reflects longer wavelength light. Other components such as an angle-selective reflecting layer, a reflective polarizer and a waveplate, etc., may also be provided. The exciting light source may be a light emitting diode (LED) or a laser diode (LD) emitting in the UV and/or blue region (for example, 360 nm, 405 nm and 420 nm, or combinations thereof). The wavelength conversion materials are preferably phosphorescent materials, including phosphors and nano-materials such as quantum dots. Fluorescent materials may also be used as wavelength conversion materials, but they may not be suitable for certain applications such as projectors that require a relatively fast emission response. The absorption spectrum of the conversion material preferably covers the wavelengths of the excitation light. The emission wavelength of the conversion material may be broad (e.g., a broad range or the whole visible range) or narrow (single color, such as red, blue and green). Different phosphors with different emission spectra may be provided on the plate.
With reference to
The light source 100 may be regular lamps, or solid-state light source including laser and light emitting diodes (LED). For solid-state light sources, the wavelength of the light typically ranges from 300 nm to 500 nm. Fox example, many LED manufacturers produce light emitting diodes emitting at 460 nm (so called Blue LED). Cree Inc. produces deep blue LEDs near 400 nm. Nichia Co. produces UV LEDs near 365 nm. Laser manufacturers such as Sharp and Nichia produce lasers emitting near 405 nm. One major advantage of solid-state light sources over conventional lamps including mercury lamp is the modulation capability. Both lasers and LEDs can be modulated at a frequency higher than one mega Hertz.
The rotary wheel configuration of
Multicolor illumination devices according to embodiments of the present invention have many advantages. For example, light at various peak wavelengths can be easily obtained. One set of LD or LED excitation light sources with similar wavelength can be used. No color wavelength division multiplexer in the visible region is required. The output colors are not limited by the LD or LED chips. It also simplifies the image projection design. The peak wavelengths of the emitted light can be rapidly changed, and the intensity can be easily modulated. In addition, when appropriate focusing and collecting optics is used, the emitted light has a small Etendue. Such multicolor illumination devices may be useful in mini projectors.
It will be apparent to those skilled in the art that various modification and variations can be made in the multicolor illumination device of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover modifications and variations that come within the scope of the appended claims and their equivalents.
Claims
1. An illumination device for providing multicolor light, comprising:
- a light source for generating an excitation light;
- a plate including two or more segments, wherein one or more of the segments each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light,
- wherein a first segment contains a first wavelength conversion material, and a second segment either contains a different wavelength conversion material or contains no wavelength conversion material,
- wherein a part of the plate is disposed on an optical path of the excitation light, and wherein the plate and the excitation light are moveable relative to each other so that different segments are exposed to the excitation light at different times; and
- a dichroic element disposed between the wavelength conversion material and the light source, the dichroic element transmitting the excitation light and reflecting light emitted by the wavelength conversion materials.
2. The illumination device of claim 1, wherein the light source is a solid-state light source.
3. The illumination device of claim 2, wherein the light source is a laser diode or a light emitting diode.
4. The illumination device of claim 2, wherein the light source includes multiple laser diodes, multiple light emitting diodes, or both laser diodes and light emitting diodes.
5. The illumination device of claim 4, further comprising:
- an optic fiber coupler or an optic fiber bundle for combining light generated by the laser diodes or light emitting diodes or both.
6. The illumination device of claim 1, further comprising:
- focusing optics disposed between the light source and the plate.
7. The illumination device of claim 1, wherein the plate is made of an optical transparent material.
8. The illumination device of claim 1, wherein the plate has a round shape and is divided by radial lines into the two or more segments, and wherein the plate is supported to rotate about an axis.
9. The illumination device of claim 1, wherein the plate includes two or more wavelength conversion materials.
10. The illumination device of claim 1, wherein the wavelength conversion materials include phosphors or quantum dots.
11. The illumination device of claim 1, wherein the wavelength conversion materials are doped into a material that forms the plate.
12. The illumination device of claim 1, wherein the wavelength conversion materials are formed on a surface of the plate.
13. The illumination device of claim 1, wherein the wavelength conversion materials are attached to a surface of the plate.
14. The illumination device of claim 1, wherein the plate defines a groove and the wavelength conversion materials are located in the groove.
15. The illumination device of claim 1, wherein the dichroic filter is a band-pass coating on the plate facing the light source.
16. The illumination device of claim 1, further comprising:
- an angle-selective reflecting layer located adjacent the wavelength conversion material on a side opposite to the light source, the angle-selective reflecting layer substantially transmitting light having an incident angle smaller than a predefined angle and substantially reflecting light having an incident angle larger than the predefined angle.
17. The illumination device of claim 1, further comprising:
- a reflector cup with an exit aperture disposed adjacent the wavelength conversion material, the exit aperture having an area smaller than an emission area of the wavelength conversion material.
18. The illumination device of claim 1, wherein the segments of the plate are arranged linearly and the plate oscillates linearly.
19. The illumination device of claim 18, wherein the plate includes repeating sets of multiple wavelength conversion materials.
20. The illumination device of claim 1, further comprising:
- a reflective polarizer disposed adjacent the wavelength conversion material, the reflective polarizer transmitting light in one polarization state and reflecting light in another polarization state.
21. The illumination device of claim 20, further comprising:
- a waveplate located between the reflective polarizer and the wavelength conversion layer.
22. The illumination device of claim 21, wherein the waveplate is a quarter-wave waveplate.
23. The illumination device of claim 1, wherein the light source includes a plurality of sources emitting at different wavelengths.
24. The illumination device of claim 23, wherein a first and a second source are located on one side of the plate, the device further comprising:
- a dichroic plate located between the sources and the wavelength conversion material to combine excitation light from the first and second sources, the dichroic plate transmitting the excitation light from the first source in one wavelength range and reflecting the excitation light from the second source in other wavelength range.
25. The An illumination device of claim 23 for providing multicolor light, wherein a first and a second source are located on both side of the plate, the device further comprising:
- a light source for generating an excitation light, wherein the light source includes at least first and second sources emitting at different wavelengths;
- a plate including two or more segments, wherein one or more of the two or more segments each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light, wherein a first segment of the plate contains a first wavelength conversion material, and a second segment of the plate either contains a different wavelength conversion material or contains no wavelength conversion material, wherein a part of the plate is disposed on an optical path of the excitation light, wherein the first and second sources are located on opposite sides of the plate, and wherein the plate and the excitation light are moveable relative to each other so that different segments of the plate are exposed to the excitation light at different times;
- a dichroic element disposed between the wavelength conversion materials and the light source, the dichroic element transmitting the excitation light and reflecting light emitted by the wavelength conversion materials; and
- a dichroic plate located between the second source and the wavelength conversion materials, the dichroic plate transmitting excitation light from the second source in one wavelength range and reflecting light emitted by the wavelength conversion material.
26. The illumination device if claim 1, wherein the light source is driven by a pulse width modulated signal.
27. A method for generating multicolor light, comprising:
- generating an excitation light using a light source;
- directing the excitation light onto a segment of a plate, the plate having two or more segments, wherein one or more of the segments each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light, wherein a first segment contains a first wavelength conversion material, and a second segment either contains a different wavelength conversion material or contains no wavelength conversion material, the plate further including a dichroic filter disposed between the wavelength conversion material and the light source, the dichroic filter transmitting the excitation light and reflecting light emitted by the wavelength conversion materials; and
- moving the plate and the excitation light relative to each other so that different segments are exposed to the excitation light at different times to generate emitted light of different colors.
28. The method of claim 27, wherein the light source is a laser diode or a light emitting diode.
29. The method of claim 27, wherein the wavelength conversion materials include phosphors or quantum dots.
30. The method of claim 27, wherein the plate further comprises
- an angle-selective reflecting layer located adjacent the wavelength conversion material on a side opposite to the light source, the angle-selective reflecting layer substantially transmitting light having an incident angle smaller than a predefined angle and substantially reflecting light having an incident angle larger than the predefined angle.
31. A method for generating multicolor light, comprising:
- generating an excitation light using a light source;
- directing the excitation light onto a segment of a plate, the plate having two or more segments, wherein one or more of the segments each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light, wherein a first segment contains a first wavelength conversion material, and a second segment either contains a different wavelength conversion material or contains no wavelength conversion material;
- moving the plate and the excitation light relative to each other so that different segments are exposed to the excitation light at different times to generate emitted light of different colors;
- projecting the light of different colors emitted from the wavelength conversion materials toward a display screen using a microdisplay imager;
- modulating the light source;
- controlling the relative movement of the plate and the light source, the microdisplay imager, and the modulation of the light source in a synchronized manner to generate an image on the display screen.
32. A method for generating a colored light, comprising:
- generating an excitation light using a light source;
- directing the excitation light onto a segment of a plate, the plate having two or more segments, wherein one or more of the segments each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light, wherein a first segment contains a first wavelength conversion material, and a second segment either contains a different wavelength conversion material or contains no wavelength conversion material;
- moving the plate and the excitation light relative to each other so that different segments are exposed to the excitation light at different times to generate emitted light of different colors;
- modulating the light source; and
- controlling the relative movement of the plate and the excitation light and the modulation of the light source in a synchronized manner to generate a colored light.
33. An illumination device for providing multicolor light, comprising:
- one or more light sources each for generating an excitation light;
- one or more optic fibers for transmitting the excitation light generated by the one or more light sources;
- a plate including two or more segments, wherein one or more of the segments each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light,
- wherein a first segment contains a first wavelength conversion material, and a second segment either contains a different wavelength conversion material or contains no wavelength conversion material,
- wherein a part of the plate is disposed on an optical path of the excitation light outputted by the optical fibers, and wherein the plate and the optical fibers are moveable relative to each other so that different segments are exposed to the excitation light at different times.
34. The illumination device of claim 25, wherein the first source and the second source are located on opposite sides of the plate.
35. An illumination device for providing multicolor light, comprising:
- a light source for generating an excitation light in a blue region;
- a plate including one or more segments each containing a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light, wherein the wavelength conversion material of the segments is doped into the plate, wherein a part of the plate is disposed on an optical path of the excitation light, and wherein the plate and the excitation light are moveable relative to each other so that the one or more segments are exposed to the excitation light at different times;
- focusing optics disposed between the light source and the plate to focus the excitation light onto the plate; and
- a dichroic element disposed between the wavelength conversion material and the light source, the dichroic element transmitting the excitation light and reflecting light emitted by the wavelength conversion material,
- wherein a first segment of the plate contains a first wavelength conversion material which absorbs a first portion of the excitation light, emits a corresponding light having a first wavelength different from that of the excitation light, and transmits a second portion of the excitation light to produce a combined multi-color light of the corresponding light having the first wavelength and the second portion of the excitation light.
36. A method for generating multicolor light, comprising:
- generating an excitation light in a blue region using a light source;
- directing the excitation light onto a segment of a plate, the plate having two or more segments, including focusing the excitation light into a light spot on the plate, one or more segments of the plate each containing a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light,
- wherein the wavelength conversion material of the one or more segments is doped into the plate, the plate further including a dichroic filter disposed between the wavelength conversion material and the light source, and the dichroic filter transmitting the excitation light and reflecting light emitted by the wavelength conversion materials; and
- moving the plate and the excitation light relative to each other so that different segments of the plate are exposed to the excitation light at different times to generate emitted light of different colors,
- wherein a first segment of the plate contains a first wavelength conversion material which absorbs a first portion of the excitation light, emits a corresponding light having a first wavelength different from that of the excitation light, and transmits a second portion of the excitation light to produce a combined multi-color light of the corresponding light having the first wavelength and the second portion of the excitation light.
37. An illumination device for providing multicolor light, comprising:
- a light source for generating an excitation light in a blue region, the light source including one or more laser diodes or light emitting diodes;
- a plate including two or more segments, wherein one or more segments of the plate each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light, wherein a first segment of the plate contains a first wavelength conversion material, and a second segment of the plate either contains a different wavelength conversion material which absorbs a portion of the excitation light and transmits a portion of the excitation light to produce a combined light or contains no wavelength conversion material, wherein a part of the plate is disposed on an optical path of the excitation light, wherein the plate and the excitation light are moveable relative to each other so that different segments are exposed to the excitation light at different times, and
- wherein the wavelength conversion material of the one or more segments is doped into the plate;
- focusing optics disposed between the light source and the plate to focus the excitation light into a light spot onto the plate, the light spot being larger than a size of the light source; and
- a dichroic element disposed between the wavelength conversion material and the light source, the dichroic element transmitting the excitation light and reflecting light emitted by the wavelength conversion materials.
38. An illumination device for providing multicolor light, comprising:
- a light source for generating an excitation light;
- a plate including two or more segments,
- wherein one or more segments of the plate each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light,
- wherein a first segment of the plate contains a first wavelength conversion material, and a second segment of the plate either contains a different wavelength conversion material or contains no wavelength conversion material,
- wherein the wavelength conversion materials are doped into a material that forms the plate,
- wherein a part of the plate is disposed on an optical path of the excitation light, and
- wherein the plate and the excitation light are moveable relative to each other so that different segments of the plate are exposed to the excitation light at different times; and
- a dichroic element disposed between the wavelength conversion material and the light source, the dichroic element transmitting the excitation light and reflecting light emitted by the wavelength conversion materials.
39. An illumination device for providing multicolor light, comprising:
- a light source for generating an excitation light;
- a plate including two or more segments,
- wherein one or more segments of the plate each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light,
- wherein a first segment of the plate contains a first wavelength conversion material, and a second segment of the plate either contains a different wavelength conversion material or contains no wavelength conversion material,
- wherein a part of the plate is disposed on an optical path of the excitation light,
- wherein the plate and the excitation light are moveable relative to each other so that different segments of the plate are exposed to the excitation light at different times, and
- wherein the plate defines a groove and the wavelength conversion materials are located in the groove; and
- a dichroic element disposed between the wavelength conversion material and the light source, the dichroic element transmitting the excitation light and reflecting light emitted by the wavelength conversion materials.
40. An illumination device for providing multicolor light, comprising:
- a light source for generating an excitation light, wherein the light source includes at least first and second sources emitting at different wavelengths;
- a plate including two or more segments,
- wherein one or more segments of the plate each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light,
- wherein a first segment of the plate contains a first wavelength conversion material, and a second segment of the plate either contains a different wavelength conversion material or contains no wavelength conversion material,
- wherein a part of the plate is disposed on an optical path of the excitation light,
- wherein the plate and the excitation light are moveable relative to each other so that different segments are exposed to the excitation light at different times, and
- wherein the first source and the second source are located on one side of the plate;
- a dichroic plate located between the sources and the wavelength conversion material to combine excitation light from the first and second sources, the dichroic plate transmitting the excitation light from the first source in one wavelength range and reflecting the excitation light from the second source in another wavelength range; and
- a dichroic element disposed between the wavelength conversion material and the light source, the dichroic element transmitting the excitation light and reflecting light emitted by the wavelength conversion materials.
41. An illumination device for providing multicolor light, comprising:
- one or more light sources each for generating an excitation light;
- one or more optic fibers for transmitting the excitation light generated by the one or more light sources;
- a plate including two or more segments,
- wherein one or more segments of the plate each contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light, wherein a first segment of the plate contains a first wavelength conversion material, and a second segment of the plate either contains a different wavelength conversion material or contains no wavelength conversion material, wherein the wavelength conversion material of the segments is doped into the plate, wherein a part of the plate is disposed on an optical path of the excitation light outputted by the optical fibers, and wherein the plate and the optical fibers are moveable relative to each other so that different segments of the plate are exposed to the excitation light at different times.
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Type: Grant
Filed: Apr 1, 2016
Date of Patent: Jul 21, 2020
Assignee: Appotronics Corporation Limited (Shenzhen)
Inventors: Yi Li (Pleasanton, CA), Li Xu (Saratoga, CA)
Primary Examiner: Albert J Gagliardi
Application Number: 15/088,548
International Classification: G03B 21/20 (20060101); H05B 45/20 (20200101); H04N 9/31 (20060101); F21V 17/04 (20060101); F21S 10/02 (20060101); F21V 7/00 (20060101); F21S 10/00 (20060101); F21Y 115/10 (20160101); F21Y 115/30 (20160101);