EP0458601A1
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EP
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Method of and apparatus for measuring spectral absorption in opaque specimens and method of and apparatus for measuring microscopic absorption distribution
Assignee: Japan Science and Technology Agency
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Filing: 1991-05-21
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Granted: —
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Expires: 2011-05-21
Abstract
Abstract For measuring spectral absorption characteristics of an opaque specimen, apparatus of Fig. 4 comprises a variable wavelength laser which can continuously emit monochromatic light over a wide spectral range, a beam converter 11 positioned to convert light from the laser into parallel rays, a beam splitter BS positioned to produce from the beam (i) rectilinear light which strikes a specimen 20 which transmits light, e.g. a dilute suspension or translucent biological specimen, which scatters the light, the forward component of which is combined with the incident light by a half-mirror HM, and (ii) reflected light which passes through a shifter AO where its frequency is slightly changed before being recombined with the forward scattered light in a detector 2 which can be a highly directional detecting system or a heterodyne system, which are further described (Figs. 1 to 3). For measurement of absorption of a specimen within a scattering medium, the final light path is modified by altering the position of the half-mirror (HM) and of the specimen 21, which is placed behind a sample of the medium NZ, so that the light passing through the medium is reflected by the specimen and again through the medium and then combines with the forward scattered light at the half-mirror and passed to the detector. Several other arrangements of the components of the apparatus are shown, for measuring various types of specimen which absorb or scatter light, including some which use a Michelson light-receiving system for a reflecting specimen, or a highly directional optical system. For measuring spectral absorption characteristics of a reflecting specimen when the intensity of the reflection component of incident light is high, the regular reflection component is removed in apparatus (Figs. 10 and 11) by means of a beam trap BT which receives light from the specimen 21 via an angled mirror M5. Other apparatus can measure either transmission or reflection spectral absorption characteristics in a microsized region (Figs. 12 and 13) and including Cassegrain reflection optical systems disposed confocally and having a pin-hole P at the confocal point, from which the scattered light extracted passes to a detector 2. Modifications of the apparatus allow a microscopic absorption distribution in an opaque specimen to be measured, by changing the relation between the specimen and the beam of directional parallel light, so as to apply incident light to a very small point region corresponding to a 0-order difraction component (Figs. 15A to 17). The spectral absorption characteristics of a specimen are thus measured with high accuracy and simply and without picking up extraneous scattered light, and the invention is especially useful for examination of specimens of animal tissue.
Inventors
- 👤 Tsutomu Dai 2 Green Haitsu-Zuiho 301 Ichimura
- 👤 Fumio Inaba
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 21:28
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/4795; G02; G02B; G02B21/00; G02B21/0004; G02B21/002; G01N2021/1738; G01N2021/1742; G01N21/41; G01N21/45; G01N2021/451; G01N2021/4704; G01N2021/4707; G01N2021/4709; G01N21/25; G01N21/31; G01N21/39
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
60 words
A method of measuring spectral absorption in an opaque specimen, comprising the steps of: illuminating a scattering specimen with highly directional light of variable wavelength from a specific direction; and detecting the intensity of only a component transmitted or reflected in a specific direction by use of a highly directional detecting system, thereby measuring spectral absorption characteristics of said specimen.
Claim 2
Dependent Claim
33 words
The measuring method of Claim 1, wherein said specific direction in which the intensity is detected by said highly directional detecting system is a direction for detection of light transmitted by said specimen.
Claim 3
Dependent Claim
35 words
The measuring method of Claim 1, wherein said specific direction in which the intensity is detected by said highly directional detecting system is a direction for detection of light reflected and scattered by said specimen.
Claim 4
Independent Claim
146 words
An apparatus for measuring spectral absorption in an opaque specimen, comprising: a monochromatic light source capable of varying the wavelength of light emitted therefrom; means for dividing the light from said light source into two light beams; means for shifting the frequency of incident light, said shift means being provided in the optical path of one of said two light beams; a scattering specimen being disposable in the optical path of the other light beam; means for combining together highly directional light emerging from said frequency shift means and a beam of parallel rays (rectilinear component) emerging from said specimen in a specific direction and projecting the resulting composite light in the same direction; and means for converting the composite light from said beam combining means into an electric signal and detecting the intensity of only an AC component which is equal to the shifted frequency.
Claim 5
Independent Claim
158 words
An apparatus for measuring spectral absorption in an opaque specimen, comprising: a monochromatic light source capable of varying the wavelength of light emitted therefrom; means for dividing the light from said light source into two light beams; means for changing the optical path length at a predetermined speed, said optical path length changing means being provided in the optical path of one of said two light beams; a scattering specimen being disposable in the optical path of the other light beam; means for combining together highly directional light emerging from said optical path length changing means and a beam of parallel rays (rectilinear component) emerging from said specimen in a specific direction and projecting the resulting composite light in the same direction; and means for converting the composite light from said beam combining means into an electric signal and detecting the intensity of only an AC component of a frequency corresponding to the optical path length changing speed.
Claim 6
Independent Claim
71 words
An apparatus for measuring spectral absorption in an opaque specimen, comprising: a monochromatic light source capable of varying the wavelength of light emitted therefrom; a scattering specimen being disposable in the optical path of light emitted from said light source; a highly directional optical system for extracting light emerging from said specimen in a specific direction; and means for detecting the intensity of light extracted by said highly directional optical system.
Claim 7
Dependent Claim
122 words
The measuring apparatus of Claim 6, further comprising switching means which is provided in the optical path of light emitted from said light source to switch over two optical paths from one to the other, said two optical paths being coaxial but opposite to each other in the direction of travel of light, said highly directional optical system being disposed in the coaxial optical paths, and said scattering specimen being disposed at one side of said highly directional optical system, thereby taking out parallel rays (rectilinear component rays) transmitted through said specimen in a specific direction or parallel rays (rectilinear component rays) reflected and scattered by said specimen in a specific direction from the other side of said highly directional optical system.
Claim 8
Dependent Claim
73 words
The measuring apparatus of any one of Claims 1 to 3, 6 and 7, wherein the intensity of part of the illuminating light beam is detected to obtain a reference light intensity, and a light intensity that is detected by use of the highly directional detecting system is defined as a signal intensity of specimen light, thereby obtaining a transmission integral extinction by use of said reference light intensity and said signal intensity.
Claim 9
Dependent Claim
112 words
The measuring apparatus of Claim 4 or 5, wherein, with light from said scattering specimen being cut off, the intensity of highly directional light emerging from said frequency shift means or said optical path length changing means is detected to obtain a reference light intensity, and light obtained from said beam combining means is converted into an electric signal and an AC component which is equal to the shifted frequency or an AC component of a frequency corresponding to the optical path length changing speed is defined as a signal intensity obtained from said specimen, thereby obtaining a transmission integral extinction by use of said reference light intensity and said signal intensity.
Claim 10
Independent Claim
84 words
A method of measuring a microscopic absorption distribution in an opaque specimen, comprising the steps of: illuminating a very small measuring point on a specimen with condensed light of high directivity; converting light diverging from said measuring point in a specific direction into parallel rays; detecting the intensity of only the parallel rays by use of a highly directional detecting system; and repeating said detecting operation with said specimen being scanned relative to said condensed light, thereby measuring absorption distribution characteristics of said specimen.
Claim 11
Dependent Claim
41 words
The measuring method of Claim 10, wherein the illuminating region is restricted by disposing a pinhole in extremely close proximity to said measuring point, said pinhole being smaller than the size of a 0-order Fraunhofer diffraction pattern of said condensed light.
Claim 12
Dependent Claim
19 words
The measuring method of Claim 10 or 11, wherein said light of high directivity is light of variable wavelength.
Claim 13
Dependent Claim
53 words
The measuring method of Claim 10 or 11, wherein an excited light cut-off filter is inserted in the optical path that extends from said measuring point to said detecting system to cut off light of the same wavelength as that of the illuminating light to measure a microscopic fluorescence distribution in said specimen.
Claim 14
Dependent Claim
75 words
The measuring method of any one of Claims 10 to 12, wherein the intensity of part of the light beam applied to said specimen is detected to obtain a reference light intensity, and a light intensity that is detected by use of the highly directional detecting system is defined as the intensity of signal light from said specimen, thereby obtaining a transmission integral extinction by use of said reference light intensity and said signal intensity.
Claim 15
Independent Claim
187 words
An apparatus for measuring a microscopic absorption distribution in an opaque specimen, comprising: a monochromatic light source capable of varying the wavelength of light emitted therefrom; means for dividing the light from said light source into two light beams; means for shifting the frequency of incident light, said shift means being provided in the optical path of one of said two light beams; a confocal optical system comprising two convergent optical systems, said confocal optical system being disposed in the other optical path; a specimen being disposable at a position where light is condensed by said confocal optical system, said specimen being capable of being scanned relative to said confocal optical system; means for combining together highly directional light emerging from said frequency shift means and light diverging from a measuring point on said specimen and converted into parallel rays by said confocal optical system and projecting the resulting composite light in the same direction; and means for converting the composite light from said beam combining means into an electric signal and detecting the intensity of only an AC component which is equal to the shifted frequency.
Claim 16
Independent Claim
199 words
An apparatus for measuring a microscopic absorption distribution in an opaque specimen, comprising: a monochromatic light source capable of varying the wavelength of light emitted therefrom; means for dividing the light from said light source into two light beams; means for changing the optical path length at a predetermined speed, said optical path length changing means being provided in the optical path of one of said two light beams; a confocal optical system comprising two convergent optical systems, said confocal optical system being disposed in the other optical path; a specimen being disposable at a position where light is condensed by said confocal optical system, said specimen being capable of being scanned relative to said confocal optical system; means for combining together highly directional light emerging from said optical path length changing means and light diverging from a measuring point on said specimen and converted into parallel rays by said confocal optical system and projecting the resulting composite light in the same direction; and means for converting the composite light from said beam combining means into an electric signal and detecting the intensity of only an AC component of a frequency corresponding to the optical path length changing speed.
Claim 17
Independent Claim
132 words
An apparatus for measuring a microscopic absorption distribution in an opaque specimen, comprising: a monochromatic light source capable of varying the wavelength of light emitted therefrom; a confocal optical system comprising two convergent optical systems, said confocal optical system being disposed in the optical path of light emitted from said light source; a specimen being disposable at a position where light is condensed by said confocal optical system, said specimen being capable of being scanned relative to said confocal optical system; a highly directional optical system arranged to extract only light traveling in the direction of travel of light diverging from a measuring point on said specimen and converted into parallel rays by said confocal optical system; and means for detecting the intensity of light extracted by said highly directional optical system.
Claim 18
Dependent Claim
109 words
The measuring apparatus of Claim 17, further comprising: switching means which is provided in the optical path of light emitted from said light source to switch over two optical paths from one to the other, said two optical paths being coaxial but opposite to each other in the direction of travel of light; said confocal optical system being disposed in the coaxial optical paths; means for taking out light transmitted through said specimen or light reflected and scattered by said specimen, said means being disposed at one side of said confocal optical system; and said highly directional optical system being disposed in the rear of said light taking-out means.
Claim 19
Independent Claim
233 words
An apparatus for measuring a microscopic absorption distribution in an opaque specimen, comprising: a monochromatic light source capable of varying the wavelength of light emitted therefrom; means for dividing the light from said light source into two light beams; means for shifting the frequency of incident light, said shift means being provided in the optical path of one of said two light beams; a first convergent optical system disposed in the other optical path to illuminate a very small measuring point on a specimen with condensed light of high directivity; a specimen beins disposable at a position where light is condensed by said first convergent optical system, said specimen being capable of being scanned relative to said first convergent optical system; a second convergent optical system arranged to illuminate said specimen with highly directional light emerging from said frequency shift means in the form of the same convergent spherical wave as that obtained from said first convergent optical system; means for combining together light emerging from said frequency shift means and light diverging from the measuring point on said specimen and converted into parallel rays by said second convergent optical system and projecting the resulting composite light in the same direction; and means for converting the composite light from said beam combining means into an electric signal and detecting the intensity of only an AC component which is equal to the shifted frequency.
Claim 20
Dependent Claim
113 words
The measuring apparatus of any one of Claims 15, 16 and 19, wherein, with light from said scattering specimen being cut off, the intensity of light emerging from said frequency shift means or said optical path length changing means is detected to obtain a reference light intensity, and light obtained from said beam combining means is converted into an electric signal and an AC component which is equal to the shifted frequency or an AC component of a frequency corresponding to the optical path length changing speed is defined as a signal intensity from said specimen, thereby obtaining a transmission integral extinction by use of said reference light intensity and said signal intensity.
References Cited (Backward Citations)
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