IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0411559
(2003-04-10)
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발명자
/ 주소 |
- Tzeng,Paul
- Blair,Randall J.
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출원인 / 주소 |
- Tzeng,Paul
- Blair,Randall J.
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인용정보 |
피인용 횟수 :
8 인용 특허 :
0 |
초록
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A MEMS-based optical, wireless communication system ( 10) that is comprised of a receiving and transmitting optical unit (12) that is further comprised of a transmitting subsystem ( 14) and a receiving subsystem (60), both of which are controlled by a microcontroller (16) and firmware (96). The syst
A MEMS-based optical, wireless communication system ( 10) that is comprised of a receiving and transmitting optical unit (12) that is further comprised of a transmitting subsystem ( 14) and a receiving subsystem (60), both of which are controlled by a microcontroller (16) and firmware (96). The system (10) is designed to allow a first unit (12) to transmit through free space a modulated laser beam (39) that is received by a second unit (12) located within line-of-sight of the first unit (12). Conversely, the second unit (12) can likewise transmit a modulated laser beam (39) that is received by the first unit (12) or other line-of-sight units (12). The system (10) features a MEMS mirror assembly (34) that operates in combination with a quad sensor (100). The combination allows fast, precise tracking and compensates for atmospheric disturbances associated with optical communication namely, building sway, wind and scintillations caused by changes in the refraction index of the atmosphere.
대표청구항
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The invention claimed is: 1. A MEMS-based optical, wireless communication system comprising: A. a first receiving and transmitting optical unit having means for receiving and processing an input data signal and producing a modulated laser beam that is transmitted through free space, and B. a second
The invention claimed is: 1. A MEMS-based optical, wireless communication system comprising: A. a first receiving and transmitting optical unit having means for receiving and processing an input data signal and producing a modulated laser beam that is transmitted through free space, and B. a second receiving and transmitting optical unit located at a distance but within line-of-sight from said first unit, wherein said second unit having means for receiving and processing the first modulated laser beam applied from said first unit, wherein said second unit also having means for producing a second modulated laser beam that is transmitted through free space and received and processed by said first unit, thus creating a bi-directional communication system, wherein said first and second receiving and transmitting optical units further comprise: a) a transmitting subsystem comprising: (1) a microcontroller having means for receiving and processing the input data signal and producing an electrical output data signal, (2) a laser driver having means for receiving and processing the output data signal and producing a modulated laser signal, (3) a laser diode having means for being energized by the modulated laser signal and producing a modulated laser beam, (4) an adjustable collimator having means for receiving the modulated laser beam and producing a collimated laser beam of adjustable divergence, (5) a MEMS mirror assembly having means for reflecting and positioning the collimated laser beam, and (6) a transmitting telescope having means for receiving the modulated laser beam and producing a steerable modulated laser beam that is transmitted through free space, and (b) a receiving subsystem comprising: (1) a receiving telescope that is positioned within line-of-sight of said transmitting telescope having a steerable field of regard and, said receiving telescope having means for receiving the modulated laser beam transmitted from said transmitting telescope and producing a focused laser beam, (2) a narrow-band filter having means for receiving and passing only the focused laser beam, and producing a focused and filtered laser beam, (3) a photodiode having means for receiving the focused and filtered laser beam and producing an electrical signal, and (4) an amplifier having means for receiving the electrical signal from said photodiode and producing an amplified signal that is applied to said microcontroller for further processing. 2. The system as specified in claim 1 wherein said second receiving and transmitting optical unit is comprised of at least one unit. 3. The system as specified in claim 2 wherein the data for control of said MEMS mirror assembly on said second receiving and transmitting optical unit is mixed with the input data stream and separated from the original input data by said second receiving and transmitting optical unit. 4. The system as specified in claim 1 wherein said laser driver is comprised of a variable electrical energy source. 5. The system as specified in claim 1 wherein said laser diode operates at an emitting frequency between 780 nm and 1550 nm, and has an average output power ranging between one mw to several hundred mw. 6. The system as specified in claim 1 wherein said collimator is comprised of a first lens and an axially-aligned second lens, wherein said lenses can be positioned to collimate the modulated laser beam from 7 to 22 degrees, to substantially a one milliradian divergence angle. 7. The system as specified in claim 1 wherein said transmitting telescope is comprised of a larger first lens and a smaller second lens, wherein the two lenses operate in combination to further collimate the modulated laser beam positioned by said MEMS mirror assembly. 8. The system as specified in claim 7 wherein the divergence angle of the modulated laser beam can be further reduced by selectively altering the ratio of the focal length of the first and second lenses of said transmitting telescope. 9. The system as specified in claim 1 wherein said MEMS mirror assembly has means for reflecting and positioning the collimated laser beam prior to being applied to said transmitting telescope, wherein said MEMS mirror assembly comprises: a) a MEMS mirror, b) a first pair of permanent magnets that are vertically-aligned with respect to said MEMS mirror, c) a second pair of permanent magnets that are horizontally-aligned with respect to said MEMS mirror, and d) a pair of electrical coils connected to a power source, wherein the current produced by said coils interacts with the magnetic fields produced by said magnets to allow the MEMS mirror to tilt in two orthogonal axes, wherein each axis has a deflecting angle of 짹5 degrees. 10. The system as specified in claim 9 wherein said MEMS mirror is produced on a single silicon crystal. 11. The system as specified in claim 10 wherein said MEMS mirror assembly is capable of a 짹5-degree angular movement within a 5-millisecond time period and is designed to compensate for atmospheric and physical disturbances associated with optical communication, wherein said disturbances include building sway, wind, and scintillations caused by changes in the refraction index of the atmosphere. 12. The system as specified in claim 1 wherein said receiving telescope is comprised of a receiving aperture consisting of a single lens and a narrow band filter having a 짹20 NM bandpass per laser wavelength which allows a focused laser beam to pass through. 13. The system as specified in claim 12 further comprising a quad sensor that is evenly spaced around the receiving aperture of said receiving telescope. 14. The system as specified in claim 13 wherein each said quad sensor is comprised of an averaging lens, a narrow band filter, a photodiode and an amplifier, wherein when the incoming modulated laser beam from said transmitting telescope arrives at the receiving aperture, the quad sensor output detects the x-y coordinates of the incoming modulated laser beam, and produces a signal that is applied to said microcontroller, from where said MEMS mirror assembly is activated to guide the modulated laser beam to the center of the receiving aperture. 15. The system as specified in claim 14 wherein said quad sensor is operated by means of a quad sensor processing algorithm. 16. The system as specified in claim 1 wherein said narrow band filter is comprised of a narrow bandpass filter, wherein said filter is designed to specifically filter light produced by solar phenomenon, sky irradiance and other sources. 17. The system as specified in claim 1 wherein said receiving and transmitting optical unit further comprises a display subsystem that is operated by said microcontroller, wherein said display is designed to display incoming and outgoing data. 18. The system as specified in claim 1 wherein said transmitting telescope and said receiving telescope are integrated into a dual composite telescope system capable of both transmitting and receiving data signals. 19. The system as specified in claim 1 wherein the beam diameter arriving at the receiving aperture of said receiving telescope can be set to be slightly larger than the diameter of the aperture by adjusting the lenses on said collimator and said transmitting telescope to aid detection of disturbances associated with optical communication.
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