Carl Zeiss Meditec Ag

Thomas Pabst

Ralf Ebersbach

Martin Hacker

Gerard Antkowiak

Roland Bergner

Ingo Koschmieder

Ulf Peterlein

Manfred Dick

Matthias Reich

Wilfried Bissmann

Rainer Leitgeb

Steffen Dubnack

Eberhard Hofmann

Michael Güntzschel

Heino Weigand

Michael Guentzschel

A method of controlling a semiconductor-laser-diode-based SS-interferometer system (SS=swept source), for a wide range of application suitable for use in ophthalmology, for example for imaging and for determining biometric measurement values of the eye. In a method according to the invention, by application of periodic current modulation, the operation of single semiconductor laser diode is designed such that a highly coherent spectral laser line can be adjusted with a highest possible repetition rate over a wide wavelength range. The parameters: center wavelength, sweep rate, sweep range, optical power in the eye and coherence length are adjusted such that the method is suitable for imaging and biometric applications via whole-eye scans. A semiconductor-laser-diode-based SS-interferometer system is provided, for biometric measuring of the eye. Embodiments are based for example on optical, coherence tomographic scan images. Applications lie in ophthalmological diagnostics, treatment and the preparation of surgical procedures and follow-up thereof.

Method for controlling a semiconductor-laser-diode-based SS-interferometer system

A short coherence interferometer for measuring several axially spaced-apart regions of a sample, especially of an eye, which has a measuring optical path, through which the measuring radiation falls on the sample, a tunable interferometer for the axial, relative retardation of parts of the radiation, wherein the axial relative retardation is assigned to the axial spacing of the regions and a detector for producing an interference signal from interfering measurement radiation, scattered or reflected back from the sample as sample radiation. The tunable interferometer divides the sample radiation into two parts, which are axially relatively retarded and superimposed so as to interfere. During the superimposition, the tunable interferometer forms individual radiations, which represent quadrature components of the sample radiation, and the detector detects the individual radiations.

Short coherence interferometry for measuring distances

A device for swept-source optical coherence domain reflectometry (SS OCDR) on moveable samples, particularly human eyes, for obtaining A-scans, having a measuring range according to the sample length and having a laser light source which can be adjusted by a main wave number kand at least one receiver for the light dissipated from the sample, wherein the sample is illuminated on the sample surface by a measurement beam having a diameter D by way of a coupling device. The light source has a spectral line width of &#x3b4;k&#x3c;168 mand the adjustment of the light source is carried out in &#x3c4;&#x3c;44 s/(D*k).

Device for swept source optical coherence domain reflectometry

An ophthalmological measuring system, for obtaining biometric data of an eye, provided with the necessary calibration and check devices for monitoring the functionality and the calibration status. The ophthalmological measuring system includes an illumination source for illuminating an eye with light and with a sensor for recording and analyzing back-scattered or reflected light components and a controller. At least one calibration and check system integrated in the ophthalmological measuring system for monitoring the functional and calibration status is provided. A device is also provided which houses the calibration and test structures and which reads off the individual physical data therefrom by an interface. The ophthalmological measuring system is in particular provided for determining biometrical data but can also be used for ophthalmological, dermatological or other devices which require calibration and/or functional checking at regular intervals.

Ophthalmological measuring system and method for calibrating and/or adjusting the same

An ophthalmological measuring system for determining distances and/or for tomographic imaging of ocular structures, based on an OCT method. The measuring system includes a light source with a spectral centroid (&#x3bb;), an interferometric measuring device, a scanner system, which in addition to the lateral deflection of the sample beam also has axial modulations with a frequency (f) in the sample arm, and a control and evaluation unit. The scanner performs a lateral, two-dimensional deflection of the sample beam with the aid of one or even two separate mirror elements and can in particular have axial modulation amplitudes z&#x3e;&#x3e;&#x3bb;/2. The system can also be used for scanner systems in other fields that use an OCT method, in particular a swept-source OCT method.

OCT-based ophthalmological measuring system

An optical deflection unit for targeted radiation, e.g., produced by laser or superluminescent diodes, in scanning, ophthalmological measuring and therapy systems, comprises a deflection mirror, a position sensor and a control unit, which form a control circuit for minimizing the deviation of the actual positions, detected by the position sensor, from the desired positions of the deflection mirror, whereby the optical deflection unit comprises a deflection mirror, oscillatingly movable by means of non-contacting electromagnetic drives around at least one rotation axis, and which is positioned in the direction of the, at least, one rotation axis between at least two bearings. The optical deflection unit is designed may also be used for beam guidance in high and ultrahigh vacuum installations, such as UV and EUV exposure installations for semiconductor lithography.

Optical deflection device for scanning, ophthalmologic measurement and therapy system

Device for swept-source optical coherence domain reflectometry

An ophthalmological biometric or image-producing system and method for detection and analysis of measurement data including a measurement arrangement with an illumination unit for illuminating the eye with at least one measurement beam, a signal detection unit for the detection of the light portions scattered or reflected back from the eye, a central control unit with an output unit, and a pattern generating unit which includes an optical scan unit, a control unit as well as a position sensor for measuring the realized deflections of the optical scan unit, whereby control unit, optical scan unit and position sensor can form a control circuit. Thereby, the position sensor, except for the connection within the possible control circuit, includes a connection to a unit of the measurement arrangement for optimizing measurement value logging or to the central control unit for correcting the biometric measurements or tomograms.

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Stadtroda, Germany

Thomas Pabst