Claims
- 1. A measurement apparatus for measuring optical transmission factor comprising a pair of identical units located at opposing sides of an object to be measured, each unit comprising;
- means for generating a light beam having predetermined restricted wavelength band, the light beams of the respective units being generated alternately,
- a first beam splitter through which passes a P polarization component of said light beam to an object, and offsets a S polarization component,
- a second beam splitter which couples said offset component from said first beam splitter, and a P polarization component from the other unit through said object, to a single common path,
- a photo-detector to receive said two components through said common path to provide two electrical signals relating to intensity of said two components, characterized in that
- said first beam spliter (47, 53,) has at least a first pair of opposing planes (22, 23) for input and output of an optical beam, a second pair of opposing planes (24, 25), and a polarization film (26) located along a diagonal plane of the beam splitter,
- one (24) of said second pair of opposing planes (24, 25) having a mirror surface,
- an input beam (27) to one (22) of said first pair of opposing planes (22, 23) of the beam splitter being split at the polarization film (26) into a transmit beam (28) which is transmitted towards the other (23) of the first pair of opposing planes and a reflect beam (30), which is reflected toward said mirror surface and then toward said other (23) of the first pair of opposing planes,
- said reflect beam (30) sharing a substantially common point (200) on said other plane (23) of said first pair of opposing planes with said transmit beam (28).
- 2. A measurement apparatus according to claim 1, wherein said second beam splitter has a structure substantially the same as that of said first beam splitter, but with the beams of said second beam splitter travelling in directions opposite to those occurring in said first beam splitter.
- 3. A measurement apparatus according to claim 2, wherein each of said beam splitters is positioned so that an input beam is applied to the polarization film of the beam splitter with substantially the Brewster angle.
- 4. A measurement apparatus according to claim 3, wherein difference between angle of incidence of an input beam to the polarization film and the Brewster angle is less than 5 degrees.
- 5. A measurement apparatus according to claim 1, wherein said first beam splitter is in parallelogram shape.
- 6. A measurement apparatus according to claim 5, wherein said second beam splitter is in parallelogram shape.
- 7. A measurement apparatus according to claim 6, wherein each of said beam splitters is made of glass with refraction index 1.684, and the angles between said first pair of parallel opposing planes and the polarization film are 22.degree.12', and the angles between said second pair of opposing planes and the polarization film are 24.degree.48'.
- 8. A measurement apparatus according to claim 6, wherein each of said beam splitters is made of glass of refraction index 1.684, the angles between the polarization film and the first pair of opposing planes are 29.degree.44' and 11.degree.03', respectively, and the angle between polarization film and each of the second pair of opposing planes is 33.degree.57', and one of said first opposing planes contacts with a liquid in which is the object to be measured.
Priority Claims (2)
Number |
Date |
Country |
Kind |
58-132692 |
Jul 1983 |
JPX |
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58-132691 |
Jul 1983 |
JPX |
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Parent Case Info
This is a continuation of U.S. application Ser. No. 631,615, filed July 17, 1984, now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
3872315 |
Boll |
Mar 1975 |
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Foreign Referenced Citations (1)
Number |
Date |
Country |
2152631 |
May 1973 |
DEX |
Continuations (1)
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Number |
Date |
Country |
Parent |
631615 |
Jul 1984 |
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