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US 7,982,881 B2Granted
Apparatus and method for interferometric measurement of a sample
AssigneeCarl Zeiss Meditec AG
InventorsAdolf Friedrich Fercher, Rainer Leitgeb
Life of this patent
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Abstract
A device for the interferometric measurement of a sample, in particular the eye, including an interferometer arrangement with a first measurement beam path, through which a measurement beam falls onto the sample, and a first reference beam path, through which a reference beam runs, which is applied to the measuring beam for interference. The interferometer arrangement includes a second measuring beam path and/or second reference beam path. The optical path lengths of the second measuring beam path and/or second reference beam path are different from one of the first beam paths. The wave length difference is selected according to a distance of two measuring areas which are arranged at a distance in the depth direction of the sample.
Claims24
An apparatus for interferometric measurement of a sample, comprising:
- a short-coherence interferometer arrangement, which comprises a measurement beam path through which a measurement beam is incident on the sample and returns from the sample;
- a first reference beam path, through which a first reference beam passes;
- at least one second reference beam path, through which a second reference beam passes and whose optical path length differs from that of the first reference beam path, the path length difference being selected according to a distance of two sample regions, which are spaced apart in depth direction of the sample;
- a superimposing device, which separates the measurement beam returned from the sample into a first and a second measurement beam part and separately superimposes the first measurement beam part upon the first reference beam and the second measurement beam part upon the second reference beam and then transmits the thus superimposed beams to a detector device for detection,
- wherein the superimposing device separates the measurement beam by dichroic separation and superimposes and transmits the superimposed beams spectrally separated and simultaneous to the detector device, and
- a control device connected to the detector device for determining from the detected, superimposed beams the distance between the sample regions by a Fourier spectral analysis in consideration of the path length difference of the reference beam paths.
3 more elements
A method for short-coherence interferometric measurement of a sample comprising:
- directing and letting return a measurement beam onto a sample through a measurement beam path;
- providing a first reference beam path guiding a first reference beam;
- providing a second reference beam path guiding a second reference beam, whose optical path length differs from that of the first reference beam path, wherein the path length difference is selected according to a distance between two sample regions, which are spaced apart in a depth direction of the sample;
- separating the measurement beam returned from the sample into a first and a second measurement beam part;
- separately superimposing the first measurement beam part with the first reference beam part and the second measurement beam part with the second reference beam part;
- wherein a dichroic separation is used for separating and individually superimposing of the two measurement beam parts such that separate superimposition and detection is effected in a spectrally separated and simultaneous manner for the superimposed beams detecting the superimposed radiations separately;
- determining the distance between the sample regions by Fourier spectral analysis of the detected radiations in consideration of the path length difference of the reference beam paths.
4 more elements
An apparatus for interferometric measurement of a sample, comprising:
- a short-coherence interferometer arrangement, which comprises a measurement beam path through which a measurement beam is incident on the sample and returns from the sample;
- a first reference beam path, through which a first reference beam passes;
- at least one second reference beam path, through which a second reference beam passes and whose optical path length differs from that of the first reference beam path, the path length difference being selected according to a distance between two sample regions, which are spaced apart in depth direction of the sample;
- a superimposing device, which separates the measurement beam returned from the sample into a first and a second measurement beam part and separately superimposes the first measurement beam part upon the first reference beam and the second measurement beam part upon the second reference beam and then transmits the thus superimposed beams to a detector device for detection,
- wherein the superimposing device spatially separates the measurement beam and superimposes and transmits the superimposed beams spatially separated to the detector device, and
- a control device connected to the detector device for determining from the detected, superimposed beams the distance between the sample regions by a Fourier spectral analysis in consideration of the path length difference of the reference beam paths.
3 more elements
A method for short-coherence interferometric measurement of a sample, comprising:
- directing a measurement beam onto a sample through a measurement beam path and letting the measurement beam return through the measurement beam path;
- providing a first reference beam path guiding a first reference beam;
- providing a second reference beam path guiding a second reference beam, whose optical path length differs from that of the first reference beam path, wherein the path length difference is selected according to a distance of two sample regions, which are spaced apart in a depth direction of the sample;
- separating the measurement beam returned from the sample into a first and a second measurement beam part;
- separately superimposing the first measurement beam part with the first reference beam part and the second measurement beam part with the second reference beam part;
- wherein the measurement beam is spatially separated into the first and the second measurement beam part and the two measurement beam parts are spatially separated superimposed with the reference beams to obtain two spatially separated superimposed beams;
- detecting the superimposed radiations separately;
- determining the distance between the sample regions by Fourier spectral analysis of the detected radiations in consideration of the path length difference of the beam paths.
5 more elements
Dependencies are inferred from the claim text.