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US5847827A Expired / Lapsed US ⏱️ 0.0 years remaining

Coherence biometry and coherence tomography with dynamic coherent

Assignee: Carl Zeiss Jena GmbH
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Filing: 1996-06-21
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Granted: 1998-12-08
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Expires: 2016-06-21
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Abstract

Abstract In the application of coherence distance measurement in medical biometry and in medical coherence tomography, an interferometric measurement light path is directed on the object to be measured and is focussed in order to improve the transverse resolution. Since the focus of the measurement light beam is fixed in the axial direction, high transverse resolution cannot be achieved over the entire object depth at all interferometric measurement points along the measurement light beam. This problem is not solved merely by displacing the focus along the measurement beam, since the focus will then lose coherence with respect to the reference light and the actual interferometric measurement location will then lie outside of this focus. In accordance with the invention, a simultaneous displacement of the reference light mirror be effected synchronously with the displacement of the focus by virtue of the optics generating the focus in order to maintain the coherence of the focus. The invention provides a method in which the focus is displaced and the coherence of the focus is maintained by one and the same moving optical element.

Inventors

  • 👤 Adolf Friedrich Fercher

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 02:13
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/102; G; G01; G01B; G01B11/00; G01B11/02; G01B9/00; G01B9/02; G01B9/02055; G01B9/02062; G01B9/02063; G01B9/0209; G01B9/02091

Claims Analysis

Total Claims: 23
Claim 1
Independent Claim 197 words
In a method for coherence biometry and coherence tomography with increased transverse resolution for measuring the position of light-reflecting locations along a measurement path at the surface of and in the interior of objects by means of a measurement light path of a short-coherence interferometer, in which, for the purpose of achieving interference, the path lengths of the measurement arm and the reference arm are balanced to the same optical length and the positions of the light-reflecting locations in the object along the measurement path are determined from the changes in length of the measurement light path and/or reference light path which are required for these positions to balance the path lengths, wherein the measurement light path is focussed in or on the object to be measured and the measurement focus produced in this way is moved along the measurement path in such a way that it remains coherent with respect to the reference light during the scanning movement, the improvement comprising the step of: providing the movement of the measurement focus and the wavelength equilibrium required for ensuring its coherence with respect to the reference light by means of the movement of an individual optical component.
Claim 2
Dependent Claim 197 words
In a method for coherence biometry and coherence tomography with increased transverse resolution for measuring the position of light-reflecting locations along a measurement path at the surface of and in the interior of objects by means of a measurement light path of a short-coherence interferometer, in which, for the purpose of achieving interference, the path lengths of the measurement arm and the reference arm are balanced to the same optical length and the positions of the light-reflecting locations in the object along the measurement path are determined from the changes in length of the measurement light path and/or reference light path which are required for these positions to balance the path lengths, wherein the measurement light path is focussed in or on the object to be measured and the measurement focus produced in this way is moved along the measurement path in such a way that it remains coherent with respect to the reference light during the scanning movement, the improvement comprising the step of: providing the movement of the measurement focus and the wavelength equilibrium required for ensuring its coherence with respect to the reference light by means of the movement of an individual optical component.
Claim 3
Dependent Claim 28 words
The method of claim 1, further comprising the step of detecting by a photodetector the measurement light reflected from a measurement focus point on or in the object.
Claim 4
Dependent Claim 193 words
In an arrangement for coherence biometry and coherence tomography with increased transverse resolution for measuring the position of light-reflecting locations along a measurement path at the surface of and in the interior of objects by means of a measurement light path of a short-coherence interferometer, in which, for the purpose of achieving interference, the path lengths of the measurement arm and the reference arm are balanced to the same optical length and the positions of the light-reflecting locations in the object along the measurement path are determined from the changes in length of the measurement light path and/or reference light path which are required for these positions to balance the path lengths, wherein the measurement light path is focussed in or on the object to be measured and the measurement focus produced in this way is moved along the measurement path in such a way that it remains coherent with respect to the reference light during the scanning movement, the improvement comprising: means for providing the movement of the measurement focus and the wavelength equilibrium required for ensuring coherence with respect to the reference light by the movement of an individual optical component.
Claim 5
Dependent Claim 193 words
In an arrangement for coherence biometry and coherence tomography with increased transverse resolution for measuring the position of light-reflecting locations along a measurement path at the surface of and in the interior of objects by means of a measurement light path of a short-coherence interferometer, in which, for the purpose of achieving interference, the path lengths of the measurement arm and the reference arm are balanced to the same optical length and the positions of the light-reflecting locations in the object along the measurement path are determined from the changes in length of the measurement light path and/or reference light path which are required for these positions to balance the path lengths, wherein the measurement light path is focussed in or on the object to be measured and the measurement focus produced in this way is moved along the measurement path in such a way that it remains coherent with respect to the reference light during the scanning movement, the improvement comprising: means for providing the movement of the measurement focus and the wavelength equilibrium required for ensuring coherence with respect to the reference light by the movement of an individual optical component.
Claim 6
Dependent Claim 53 words
The arrangement for coherence biometry and coherence tomography with increased transverse resolution according to claim 2, wherein a real focus which is produced by a moving concave mirror is imaged in the object to be measured in the measurement light beam of a modified Mach-Zehnder interferometer in a transverse imaging scale of 1:1/√2.
Claim 7
Dependent Claim 52 words
The arrangement for coherence biometry and coherence tomography with increased transverse resolution according to claim 2, wherein a real focus which is produced by a moving concave mirror is imaged in the object to be measured in the measurement light beam of a fiber-optics interferometer in a transverse imaging scale of 1:1.
Claim 8
Dependent Claim 43 words
The arrangement for coherence biometry and coherence tomography with increased transverse resolution according to claim 2, wherein a virtual focus which is produced by a moving convex mirror is imaged in the object to be measured in the measurement arm of an interferometer.
Claim 9
Dependent Claim 49 words
The arrangement for coherence biometry and coherence tomography with increased transverse resolution according to claim 2, wherein a real or virtual focus produced by moving optics comprising a combination of lens and plane mirror is imaged in the object to be measured in the measurement arm of an interferometer.
Claim 10
Dependent Claim 52 words
The arrangement for coherence biometry and coherence tomography with increased transverse resolution according to claim 2, wherein a real focus which is produced by a moving concave mirror is imaged in the object to be measured in the measurement light beam of a Michelson interferometer in a transverse imaging scale of 1:1.
Claim 11
Dependent Claim 24 words
The arrangement of claim 3, further comprising a photodetector for detecting measurement light reflected from a measurement focus point on or in the object.
Claim 12
Dependent Claim 221 words
In a method for coherence biometry and coherence tomography according to the dual-beam method with increased transverse resolution for measuring the position of light-reflecting locations along a measurement path at the surface of and in the interior of objects based on short-coherence interferometry, in which the object to be measured is illuminated by a dual beam formed of a measurement light beam and a reference light beam exiting from a two-beam interferometer and in which, for the purpose of achieving interference in the light returning from the object to be measured, the path lengths of the measurement arm and the reference arm of said two-beam interferometer are balanced to the same optical length and the positions of the light-reflecting locations in the object along the measurement path are determined from the changes in length in the measurement arm and/or reference arm which are required for these positions for equilibrium, wherein the reference beam is reflected at a stationary light-reflecting location of the object, while the measurement beam is focussed in or on the measurement object, and the measurement focus produced in this way is moved along the measurement path during the measurement, the improvement comprising the step of: providing the movement of the measurement focus and the interferometric path length equilibrium by means of the movement of an individual optical element.
Claim 13
Dependent Claim 221 words
In a method for coherence biometry and coherence tomography according to the dual-beam method with increased transverse resolution for measuring the position of light-reflecting locations along a measurement path at the surface of and in the interior of objects based on short-coherence interferometry, in which the object to be measured is illuminated by a dual beam formed of a measurement light beam and a reference light beam exiting from a two-beam interferometer and in which, for the purpose of achieving interference in the light returning from the object to be measured, the path lengths of the measurement arm and the reference arm of said two-beam interferometer are balanced to the same optical length and the positions of the light-reflecting locations in the object along the measurement path are determined from the changes in length in the measurement arm and/or reference arm which are required for these positions for equilibrium, wherein the reference beam is reflected at a stationary light-reflecting location of the object, while the measurement beam is focussed in or on the measurement object, and the measurement focus produced in this way is moved along the measurement path during the measurement, the improvement comprising the step of: providing the movement of the measurement focus and the interferometric path length equilibrium by means of the movement of an individual optical element.
Claim 14
Dependent Claim 218 words
In an arrangement for coherence biometry and coherence tomography according to the dual-beam method with increased transverse resolution for measuring the position of light-reflecting locations along a measurement path at the surface of and in the interior of objects based on short-coherence interferometry, in which the object to be measured is illuminated by a dual beam formed of a measurement light beam and a reference light beam exiting from a two-beam interferometer and in which, for the purpose of achieving interference in the light returning from the object to be measured, the path lengths of the measurement arm and the reference arm of said two-beam interferometer are balanced to the same optical length and the positions of the light-reflecting locations in the object along the measurement path are determined from the changes in length in the measurement arm and/or reference arm which are required for these positions for equilibrium, wherein the reference beam is reflected at a stationary light-reflecting location of the object, while the measurement beam is focussed in or on the measurement object, and the measurement focus produced in this way is moved along the measurement path during the measurement, the improvement comprising: means for providing the movement of the measurement focus and the interferometric path length equilibrium by the movement of an individual optical element.
Claim 15
Dependent Claim 218 words
In an arrangement for coherence biometry and coherence tomography according to the dual-beam method with increased transverse resolution for measuring the position of light-reflecting locations along a measurement path at the surface of and in the interior of objects based on short-coherence interferometry, in which the object to be measured is illuminated by a dual beam formed of a measurement light beam and a reference light beam exiting from a two-beam interferometer and in which, for the purpose of achieving interference in the light returning from the object to be measured, the path lengths of the measurement arm and the reference arm of said two-beam interferometer are balanced to the same optical length and the positions of the light-reflecting locations in the object along the measurement path are determined from the changes in length in the measurement arm and/or reference arm which are required for these positions for equilibrium, wherein the reference beam is reflected at a stationary light-reflecting location of the object, while the measurement beam is focussed in or on the measurement object, and the measurement focus produced in this way is moved along the measurement path during the measurement, the improvement comprising: means for providing the movement of the measurement focus and the interferometric path length equilibrium by the movement of an individual optical element.
Claim 16
Dependent Claim 43 words
The arrangement for coherence biometry and coherence tomography with increased transverse resolution according to claim 11, wherein a virtual focus which is produced by a moving convex mirror is imaged in the object to be measured in the measurement arm of an interferometer.
Claim 17
Dependent Claim 49 words
The arrangement for coherence biometry and coherence tomography with increased transverse resolution according to claim 11, wherein a real or virtual focus produced by moving optics comprising a combination of lens and plane mirror is imaged in the object to be measured in the measurement arm of an interferometer.
Claim 18
Dependent Claim 58 words
The arrangement for coherence biometry and coherence tomography with increased transverse resolution according to claim 11, wherein the dual beam is generated by a modified Michelson interferometer and a real focus which is produced by a moving concave mirror is imaged in the object to be measured in the measurement light beam in the imaging scale of 1:1.
Claim 19
Dependent Claim 59 words
The arrangement for coherence biometry and coherence tomography with increased transverse resolution according to claim 11, wherein the dual beam is generated by a modified Mach-Zehnder interferometer and a real focus which is produced by a moving concave mirror is imaged in the object to be measured in the measurement light beam in the transverse imaging scale of 1:1/√2.
Claim 20
Dependent Claim 136 words
An arrangement for scanning an object, comprising: a light source for emitting light of short coherence length; means for dividing the light into reference light and measurement light; optical means for optically focusing the measurement light on or in an object being scanned, a location on or in the object at which the measurement light is focused defining a measurement focus; means for supplying the reference light onto a detector and for supplying light reflected from the object onto the detector; and movement means for providing movement of the measurement focus and for providing a wavelength equilibrium between a measurement path and a reference path, said measurement and reference paths representing respective paths on which said measurement and reference light travel, said movement means being carried out by means of movement of an individual optical element.
Claim 21
Dependent Claim 136 words
An arrangement for scanning an object, comprising: a light source for emitting light of short coherence length; means for dividing the light into reference light and measurement light; optical means for optically focusing the measurement light on or in an object being scanned, a location on or in the object at which the measurement light is focused defining a measurement focus; means for supplying the reference light onto a detector and for supplying light reflected from the object onto the detector; and movement means for providing movement of the measurement focus and for providing a wavelength equilibrium between a measurement path and a reference path, said measurement and reference paths representing respective paths on which said measurement and reference light travel, said movement means being carried out by means of movement of an individual optical element.
Claim 22
Dependent Claim 15 words
The arrangement of claim 16, wherein said movement means is located within said measurement path.
Claim 23
Dependent Claim 28 words
The arrangement of claim 16, further comprising a detector for detecting the combined reference light and light reflected from the object, and wherein the detector is a photodetector.

References Cited (Backward Citations)

US5321501A Cited
US5459570A Cited
US5465147A Cited
US5579112A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2001-12-07 2002-06-08 2002-12-08 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2005-12-07 2006-06-08 2006-12-08 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2009-12-07 2010-06-08 2010-12-08 $7700.00 Window Closed / Lapsed

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