Optical waveguides – With optical coupler – Permanently fixed coupler
Reexamination Certificate
2000-06-01
2002-11-26
Sikder, Mohammad (Department: 2872)
Optical waveguides
With optical coupler
Permanently fixed coupler
C385S024000, C385S028000, C385S032000
Reexamination Certificate
active
06487343
ABSTRACT:
FIELD OF THE INVENTION
The present invention is a light mixer for use in connection with an optical probe of a spectrophotometric-type instrument. In particular, the invention is a mixer for combining the different wavelength light beams from a plurality of discrete optical fibers into a homogeneous beam prior to transmission into tissue being analyzed.
BACKGROUND OF THE INVENTION
Spectrophotometric-type instruments are known and used in a variety of applications. An instrument of this type is, for example, disclosed in the Anderson et al. U.S. Pat. No. 5,879,294. These instruments transmit light at a number of predetermined wavelengths through the tissue being measured, and then collect and process the light. Measurements of the tissue parameters of interest are generated as a function of the attenuation of the light at these wavelengths by the tissue. Several different approaches for obtaining the different wavelength light signals are used. One approach is to transmit through and collect from the tissue broad bandwidth light, and to separate the different wavelength signals from the collected light prior to processing. Another approach is to use light emitting diodes (LEDs) or other sources to generate narrow bandwidth light beams (i.e., signals at the wavelengths of interest). These narrow bandwidth beams are then individually transmitted to the tissue being measured by separate individual optical fibers sometimes referred to as send fibers. A drawback of the use of individual send fibers is that light from one or more of these fibers may be attenuated differently than the light from other fibers due to inhomogeneities on the surface of the tissue where the light exits the send fibers and is transmitted into the tissue (i.e., the tissue target). This drawback is possible even though the ends of the send fibers are located adjacent to one another. For example, the end of one of the fibers could be over a mole or hair, while the others are not. Inaccurate measurements can result from these circumstances.
A number of approaches for combining light from individual optical fibers are known. One approach is to fuse the individual fibers into a common fiber. Another approach is to fixture the LEDs onto an integrating sphere which mixes the light. An optical fiber at the exit port of the integrating sphere transports the light to the tissue target. Yet another method is to utilize the waveguide effect of semiconductor and other materials.
There remains, however, a continuing need for improved light mixers for use with spectrophotometric instruments. A light mixer which can effectively mix narrow bandwidth light from several optical fibers would be desirable. To be commercially viable the light mixer should be capable of being efficiently manufactured.
SUMMARY OF THE INVENTION
The present invention is an improved light mixer structure for combining light from a plurality of individual optical fibers into a single optical transmission device. One embodiment of the light mixer structure includes a plurality of optical send fibers having input and output ends and an optical mixer having input and output ends. The output ends of the send fibers are in optical communication with the input end of the light mixer. The light mixer provides a high degree of light mixing yet is capable of being efficiently manufactured.
REFERENCES:
patent: 3874781 (1975-04-01), Thiel
patent: 4910539 (1990-03-01), Mathis et al.
patent: 5212748 (1993-05-01), Curtiss et al.
patent: 5224478 (1993-07-01), Sakai et al.
patent: 5339375 (1994-08-01), Kerns
patent: 5400421 (1995-03-01), Takahashi
patent: 5548672 (1996-08-01), Hattori et al.
patent: 5584296 (1996-12-01), Cui et al.
patent: 5879294 (1999-03-01), Anderson et al.
patent: 5978534 (1999-11-01), O'Rourke et al.
patent: 0 476 596 (1992-03-01), None
patent: 0 800 099 (1997-10-01), None
patent: 0 816 829 (1998-01-01), None
patent: 1 386 734 (1975-03-01), None
patent: 1 558 643 (1980-01-01), None
Lewandowski Mark S.
Myers Dean E.
Quast Kenneth R.
Schmidt Mark A.
Faegre & Benson LLP
Hutchinson Technology Incorporated
Sikder Mohammad
LandOfFree
Fiber optic light mixer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fiber optic light mixer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fiber optic light mixer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2986273