US4781456A
Expired / Lapsed
US
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Absorption photometer
Assignee: Hitachi Ltd
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Filing: 1987-07-22
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Granted: 1988-11-01
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Expires: 2007-07-22
Abstract
Abstract An absorption photometer for measuring the absorption by conducting the light to a thin flow cell in which a liquid sample flows, wherein the sample light for measuring the absorption peak is superimposed on the reference light selected from the transparent (window) range of the liquid and the absorbance is detected by separating the sample light and reference light after transmission of the flow cell. Changes in the light path conditions can be monitored accurately, and therefore high-accuracy measurement immune to noises is made possible even using an elongated flow cell.
Inventors
- 👤 Taro Nogami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:46
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/42; G01J3/427; G01J1/00; G01J1/10; G01J1/16; G01J1/1626; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/314; G01N2021/3155
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
136 words
An absorption photometer comprising: a light source for emitting light in one wavelength range; a variable-wavelength spectrometer including dispersion means for dispersing the light depending on the wavelength; light directing means located between said light source and said dispersion means for producing more than one light beam from the light emitted by said light source and making the light beams incident to said dispersion means at different angles; means for taking out output light having different wavelengths from said dispersion means in one direction and for making the output light of different wavelength simultaneously incident to a sample in a sample cell; detection means for simultaneously detecting each light of different wavelength transmitted through said sample; and an arithmetic operation means for calculating the ratio of detection results at different wavelengths provided by said detection means.
Claim 2
Dependent Claim
136 words
An absorption photometer comprising: a light source for emitting light in one wavelength range; a variable-wavelength spectrometer including dispersion means for dispersing the light depending on the wavelength; light directing means located between said light source and said dispersion means for producing more than one light beam from the light emitted by said light source and making the light beams incident to said dispersion means at different angles; means for taking out output light having different wavelengths from said dispersion means in one direction and for making the output light of different wavelength simultaneously incident to a sample in a sample cell; detection means for simultaneously detecting each light of different wavelength transmitted through said sample; and an arithmetic operation means for calculating the ratio of detection results at different wavelengths provided by said detection means.
Claim 3
Dependent Claim
15 words
An absorption photometer according to claim 1, wherein said dispersion means comprises a diffraction grating.
Claim 4
Dependent Claim
22 words
An absorption photometer according to claim 1, wherein said sample cell comprises a flow cell in which a liquid sample is fed.
Claim 5
Dependent Claim
51 words
An absorption photometer according to claim 1, wherein said light directing means comprises a beam splitter and mirrors, and wherein said detection means comprises means for separating the light of different wavelengths trnsmitted through said sample depending on each wavelength and more than one detector for respectively detecting the separated light.
Claim 6
Dependent Claim
45 words
An absorption photometer according to claim 4, wherein said means for separating the light of different wavelengths transmitted through said sample depending on each wavelength comprises a dielectric multilayer dichroic mirror which reflects the light with one wavelength and transmits the light with another wavelength.
Claim 7
Dependent Claim
43 words
An absorption photometer according to claim 1, wherein said detection means comprises a diffraction grating and two detectors, said detectors being disposed on the light path of the zero-order diffraction light and light path of the dispersion light of said diffraction grating, respectively.
Claim 8
Dependent Claim
32 words
An absorption photometer according to claim 6, wherein said detection means further comprises a short-cut filter disposed in front of said detector located on the light path of the zero-order diffraction light.
Claim 9
Dependent Claim
35 words
An absorption photometer according to claim 1, wherein said detection means comprises a diffraction grating and two detectors, said detectors being disposed at different angular positions with respect to the dispersing direction of said grating.
Claim 10
Dependent Claim
119 words
An absorption photometer comprising: a light source capable of emitting light in one wavelength range; a diffraction grating which disperses by diffraction the light in the visual range as a first-order diffraction light and the light in the ultraviolet range as a second-order diffraction light; means for taking out the dispersion light having different wavelengths from said grating in a single direction and for making the light of different wavelengths simultaneously incident to a sample in a sample cell; detection means for separately and simultaneously detecting the light of different wavelengths transmitted through said sample depending on each wavelength; and an arithmetic operation means for calculating the ratio of detection results at different wavelengths provided by said detection means.
Claim 11
Dependent Claim
119 words
An absorption photometer comprising: a light source capable of emitting light in one wavelength range; a diffraction grating which disperses by diffraction the light in the visual range as a first-order diffraction light and the light in the ultraviolet range as a second-order diffraction light; means for taking out the dispersion light having different wavelengths from said grating in a single direction and for making the light of different wavelengths simultaneously incident to a sample in a sample cell; detection means for separately and simultaneously detecting the light of different wavelengths transmitted through said sample depending on each wavelength; and an arithmetic operation means for calculating the ratio of detection results at different wavelengths provided by said detection means.
Claim 12
Dependent Claim
22 words
An absorption photometer according to claim 9, wherein said sample cell comprises a flow cell in which a liquid sample is fed.
Claim 13
Dependent Claim
59 words
An absorption photometer according to claim 9, wherein said detection means comprises a beam splitter for separating the incident light into two light beams, a band-pass filter and a detector placed on the light path of one of the two separated light beams, and a short-cut filter and another detector placed on the light path of another light beam.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-01 | 1992-05-02 | 1992-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-01 | 1996-05-02 | 1996-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-01 | 2000-05-02 | 2000-11-01 | $7700.00 | Window Closed / Lapsed |