DE102012017833A1 - Interferometer-optical measuring system e.g. ophthalmic measurement system, for use in operating microscope for measuring defective vision of eye, has beam splitter arranged in optical path by radiation and/or receipt terminals at detector - Google Patents

Abstract

The system has a beam splitter (7) arranged in an optical path by a light source (3) at an optical delay device (25) and at light radiation and/or receipt terminal (41). The splitter is arranged in the optical path by the terminal and delay device at a detector (33). Another beam splitter (17) is arranged in the optical path by the radiation and/or receipt terminal and another light radiation and/or receipt terminal (45) at the detector. An optical component comprises a beam deflection system for the optical path between the former light radiation and/or receipt terminal and a measuring point. Independent claims are also included for the following: (1) an operating microscope (2) a method for measuring defective vision of an eye.

Description

The invention relates to an interferometer-optical measuring system and in particular to such an interferometer-optical measuring system which uses the principle of white-light interferometry. Furthermore, the invention relates to a method for measuring a refractive error of an eye.

Interferometer-optical measuring systems are used, for example, to measure the properties of a human eye. For example, the refractive error of an eye can be determined by directing measuring light onto a small area of a retina of the eye, so that the small area of the retina of the eye itself becomes a source of measuring light whose wavefronts are spherical waves from the small area of the retina out. The measuring light leaves the eye through the natural eye lens, whereby in the normal-sighted, emmetropic eye, the wavefronts of the measuring light emerging from the eye are plane wavefronts. In the case of a defective eye, the flat wavefronts are deformed into deformed wavefronts. By measuring the wavefronts it is possible to deduce the type of refractive error of the eye. Conventionally, wavefront sensors, such as Hartmann-Shack sensors, are used to measure the wavefronts. An example of an ophthalmic measuring system which employs a Hartmann-Shack sensor for measuring wavefronts is shown in FIG DE 10 2009 037 841 A1 described.

Other ophthalmic measuring systems use the principle of white light interferometry and in particular the method of optical coherence tomography to examine anatomical structures of the eye, such as those of the anterior chamber or the retina. An example of such a system is in US 2011/0176142 A1 described.

Ophthalmic measuring systems are also known which combine several of these technologies, such as optical coherence tomography for measuring anatomical structures and wavefront measurement for determining the refractive error of an eye, in one device. With such devices, a far-reaching diagnosis of the eye is possible without having to move the patient back and forth between different devices. However, the devices in which several alternative technologies are integrated for examining the eye are characterized by increased complexity.

Accordingly, it is an object of the present invention to propose alternative technologies for examining particular features of the eye, which are particularly integrated with existing technologies for examining other properties of the eye.

According to one embodiment, an interferometer-optical measuring system comprises a light source, a detector; an optical delay device; a first light emitting and / or receiving port; a second light emitting and / or receiving port; and at least one beam splitter; wherein the at least one beam splitter is arranged in a light path from the light source to the optical delay device; wherein the at least one beam splitter is disposed in a light path from the light source to the first light emitting and / or receiving port; wherein the at least one beam splitter is arranged in a light path from the light source to the second light emission and / or reception port; wherein the at least one beam splitter is arranged in a light path from the optical retarder to the detector; wherein the at least one beam splitter is disposed in a light path from the first light emitting and / or receiving port to the detector; wherein the at least one beam splitter is arranged in a light path from the second light emitting and / or receiving port to the detector.

According to a further embodiment, an interferometer-optical measuring system comprises a light source; a detector; an optical delay device; a first light emitting and / or receiving port; a second light emitting and / or receiving port; and a first beam splitter and a second beam splitter; wherein the first beam splitter is disposed in a light path from the light source to the optical delay device; wherein the first beam splitter is disposed in a light path from the light source to the first light emitting and / or receiving port; wherein the first beam splitter is disposed in a light path from the first light emitting and / or receiving port to the detector; wherein the first beam splitter is arranged in a light path from the optical retarder to the detector; wherein the second beam splitter is disposed in a light path from the first light emitting and / or receiving port to the detector; and wherein the second beam splitter is disposed in a light path from the second light emitting and / or receiving port to the detector.

In this case, the measuring system has the structure of an interferometer, wherein the light generated by the light source can reach the detector via two different paths. One of these paths is a reference optical path passing through the optical delay device, and the other is on via the two Lichtabstrahl- and / or receiving terminals extending measuring light path.

According to exemplary embodiments, the light source is a white light source, i. H. the light generated by it has a significant bandwidth and, associated therewith, a short coherence length. However, this does not require that the light of the light source must be in the visible range.

Rather, the wavelengths of the light generated by the light source may be in the infrared range.

Since the light generated by the light source has a short coherence length, a measurement signal increased or decreased by interference to the mean value is detectable with the detector if the reference light path and the measurement light path have approximately equal optical path lengths, ie. H. a difference in the optical path lengths of the two light paths is smaller than, for example, five times the coherence length of the light generated by the light source. This allows the measuring system to operate on the principle of white-light interferometry.

According to embodiments herein. the detector and the optical delay device are designed such that the measuring system can record scatter intensities as a function of the optical path length of the measuring light branch. Such techniques are known per se in the field of optical coherence tomography. For example, the optical path length of the optical delay device can be varied and the intensity of the signal detected by the detector can be recorded as a function of the instantaneous optical path length. This corresponds to the technique of Time Domain OCT (TD-OCT). In addition, there is also the technique of the frequency domain OCT (FD-OCT), in which at a fixed value of the optical path length of the optical delay device, the measurement light intensity is detected by the detector as a function of the wavelength. For this there are for example two possibilities, namely that of the spectral domain OCT (SD-OCT), in which the light which has passed through the measurement light path is subjected to the spatial separation of different wavelengths of a dispersion and directed, for example, to a line detector, and the swept-source OCT (SS-OCT), in which the wavelength of the measuring light generated by the light source is changed over time.

The measuring system has a first Lichtabstrahl- and / or receiving terminal and a second Lichtabstrahl- and / or receiving terminal, wherein a beam splitter can be provided to supply from the light source generated measuring light both the first and the second Lichtabstrahl- and / or receiving terminal. However, it is also possible for the measurement light generated by the light source to be supplied only to the first light emission and / or reception connection. Further, a beam splitter is provided to merge light which is received by the two light emitting and / or receiving ports, so that an overlay thereof reaches the detector. Thus, the measuring light path may include a light path, wherein the measuring light generated by the light source is radiated through the first Lichtabstrahl- and / or receiving terminal towards an object to be measured and scattered by the object and reflected, so that it by the second Lichtabstrahl- and / Receive port is received and directed to the detector. The emission of the light toward the object to be measured and the receiving of the light scattered and reflected back from the object thus takes place by means of two different light emission and / or reception connections. The two different Lichtabstrahl- and / or receiving terminals can be spatially separated from each other. This provides an advantage over the conventional OCT measuring system, which has a single light emitting and receiving port through which the measuring light is radiated both toward the object to be measured and the measuring light scattered and reflected back at the object. This is because the light paths of the measuring light between the one light emitting and / or receiving connection and the object or the other light emitting and / or receiving connection do not completely coincide and are at least partially different from each other. This opens the possibility to manipulate the light in these two light paths in different ways. This opens up new measurement principles.

According to embodiments, the interferometer optical measurement system is configured to measure wavefronts. In this respect, the measuring system can replace a conventional sensor for measuring wavefronts, such as a Hartmann-Shack sensor. In addition, the measuring system can then advantageously be used as an integrated interferometer-optical measuring system which, in addition to conventional interferometric measuring methods, such as the measurement of tissue structures by means of optical coherence tomography, still offers the possibility of measuring wavefronts, without a separate sensor, such as a Hartmann transducer. Shack sensor, to need.

To the measuring light on its light path between the first Lichtabstrahl- and / or receiving terminal and the measurement site and its light path be manipulated differently between the measuring location and the second Lichtabstrahl- and / or receiving terminal, according to certain embodiments, in one or both of these light paths further optical components may be arranged.

In the context of the present application, a light emission and / or reception connection is an optical interface from which measurement light can be emitted to the measurement location or to one of the further optical components and / or which receive measurement light from the measurement location or one of the further optical components may eventually lead to the detector of the interferometer optical measuring system. In particular, if the interferometer-optical measuring system has a fiber-optic construction and, for example, the at least one beam splitter is a fiber splitter, the first and / or the second light-emitting and / or receiving connection can be formed by the end of a glass fiber. It is likewise possible for the light emission and / or reception connection to comprise a lens which collimates light emerging from a glass fiber into the glass fiber for emission into the space toward the measurement location or for coupling incident light therefrom.

According to exemplary embodiments, the at least one optical component comprises a semitransparent mirror which is penetrated by the beam path between the first light emission and / or reception port and the measurement location and at which the beam path is reflected between the second light emission and / or reception port and the measurement location , In this configuration, the two Lichtabstrahl- and / or receiving terminals can be spatially spaced apart, while ensuring that both measuring light is directed through the two Lichtabstrahl- and / or receiving ports to the measuring location as well as at the measuring point scattered measuring light back in the interferometric measuring system can enter.

According to exemplary embodiments, the at least one further optical component comprises a beam deflection system for one of the beam paths between the first or the second light emission and / or reception port and the measurement location. The beam deflector system can provide an adjustable deflection angle for the beam of the measuring light, so that the measuring light can be directed to different measuring locations on an extended object. In particular, this makes it possible to scan the measurement light beam directed onto the object and thus the measurement location over the extended object and to perform a white light interferometric measurement at each individual measurement location in order to determine the scatter intensities of structures of the object as a function of the optical path length, ie. H. the depth of the object, so that scattering information on the scatter intensities of an extended volume of the object is obtained after completion of the scan.

According to exemplary embodiments, the beam deflection system comprises two mirrors arranged one behind the other in the beam path, each of which being pivotable about at least one pivot axis, the two pivot axes being oriented towards one another such that the pivoting of the one mirror results in a displacement of the measurement location on the object into a first mirror Direction leads and the pivoting of the other mirror about its pivot axis to a displacement of the measurement location on the object in a direction transverse to the first direction second direction leads.

According to further exemplary embodiments, the at least one further optical component comprises a selector arrangement which is configured to allow only a smaller partial cross section to pass from a larger overall cross section of the beam path of the measuring light, wherein a position of the partial cross section is adjustable relative to the overall cross section. The selector arrangement thus selects from the overall cross section a smaller partial cross section for further processing with the interferometer. With this configuration, it is possible to measure the shape of wavefronts of measurement light emanating from the measurement location by making a white light interferometric measurement for different positions of the partial cross section relative to the total cross section and determining from the totality of the measurements parameters which take the form of the Represent wavefront.

According to exemplary embodiments, the selector arrangement comprises two mirrors arranged one after the other in the beam path, each of which can be pivoted about two axes in each case.

According to certain embodiments, the interferometer-optical measuring system explained above is integrated into a surgical microscope, which comprises an objective and an eyepiece and / or an image sensor in order to make visible an enlarged image of the object via the eyepiece or to detect it with the image sensor. Here, the interferometer-optical measuring system with the surgical microscope is integrated such that their beam paths are partially superimposed and locations of the interferometer-optical measuring system within the object field of the surgical microscope are, which is imaged via the eyepiece or on the image sensor.

According to certain embodiments, a method for measuring a refractive error of an eye comprises generating measurement light with a light source; recording a plurality of interferences between a first part of the measuring light and a second part of the measuring light with a detector, wherein the first part of the measuring light passes through a reference light path from the light source through an optical delay device with an adjustable light path to the detector, the second part the measurement light passes through a measurement light path from the light source to the detector, and wherein the measurement light path comprises a first partial light path from the light source to a cornea of the eye and a second partial light path from the cornea to the detector; blocking a part of the measuring light in the first partial optical path or the second partial optical path such that only a partial cross section of the entire beam cross section is not blocked and can pass through the measuring optical path for a plurality of different positions of the partial cross section relative to the entire beam cross section; wherein during the recording of different interferences different partial cross sections of the entire beam cross section are not blocked; and wherein the method further comprises: determining the refractive error based on the plurality of recorded interferences and positions of the partial cross sections not blocked during the recording of the respective interferences relative to the total beam cross section.

The invention will be explained in more detail with reference to figures. Hereby shows:

1 a schematic representation of an interferometer optical measuring system according to a first embodiment;

2 a schematic representation of a portion of an interferometer-optical measuring system according to a second embodiment;

3 a schematic representation of an eye for explaining a method for measuring a defective vision with the in 2 shown measuring system;

4 a schematic representation of a surgical microscope with integrated interferometer optical measuring system;

5 a schematic representation of a selector assembly, as it can be used in an interferometer optical measuring system; and

6 a schematic representation of a portion of an interferometer-optical measuring system according to a third embodiment.

1 shows a schematic representation of an interferometer-optical measuring system 1 , This includes a light source 3 for generating short coherent light. An example of such a light source is a superluminescent diode. The light source 3 feeds the generated light into a glass fiber 5 a, so that the light generated by the glass fiber 5 a fiber optic coupler 7 is supplied, which acts as a beam splitter, so that the light generated by the optical fiber coupler 7 in two glass fibers 9 and 11 is fed. The glass fiber 9 is part of a measuring arm 13 of the interferometric measuring system 1 while the fiberglass 11 Part of a reference arm 15 of the interferometric measuring system 1 is. The glass fiber 11 of the reference arm 15 This leads through the light source 3 generated light another optical fiber coupler 35 to, which also acts as a beam splitter on this light and on two glass fibers 19 and 21 divides. The glass fiber 19 the measurement light obtained results in a photodetector 23 to which detects an intensity of the supplied light and produces a signal which is also the instantaneous intensity of the light source 3 represents generated measuring light. This signal can help stabilize the light source 3 itself or to standardize measurement results.

The glass fiber 21 leads the obtained light of an optical delay device 25 to. This includes an end 26 the fiberglass 21 from which the measuring light exits divergently, a lens 27 which collimates the divergent measuring light and onto a mirror 28 directed. That at the mirror 28 reflected measuring light is transmitted through the lens 27 back in the end 26 the fiber 21 Coupled so that it is in this towards the fiber optic coupler 17 spreads. Part of the optical delay device 25 returning light is through the fiber coupler 35 in the glass fiber 11 fed and the fiber optic coupler 7 fed, which in turn a part of this light in a glass fiber 31 feeds the light to a detector 33 supplies. Thus, measuring light passes which the reference arm 15 of the interferometer optical measuring system 1 has passed through to the detector 33 ,

That of the fiber optic coupler 7 or beam splitter in the glass fiber 9 of the measuring arm 13 fed light is through another fiber optic coupler 17 on two glass fibers 37 and 39 divided up. The glass fiber 37 the measurement light leads to a first light emission and reception connection 41 to which the light supplied to it becomes an object 43 , which is to be measured interferometrically radiates. On the object 43 At least a portion of the first light emitting and / or receiving port is received 41 on the object 43 radiated light reflected so that it from a second Lichtabstrahl- and / or receiving terminal 45 received and in the glass fiber 39 is fed. One Part of this light is through the fiber optic coupler 17 in the glass fiber 9 fed and the fiber optic coupler 7 fed, which in turn a part of this light on the glass fiber 31 the detector 33 supplies. Thus, the detector receives 33 also from the light source 3 generated measuring light, which is the measuring arm of the interferometric measuring system 1 has gone through.

On the detector 33 thus becomes the measuring light, which is the measuring arm 13 has passed through, superimposed with the measuring light, which is the reference arm 15 has gone through. The detected signal intensity generally has an average value which is determined by the intensity of the light source 3 generated measuring light, the reflectivity of the object 43 , the coupling ratios of the fiber optic coupler 7 . 17 and 35 and other parameters of the system. Due to the short coherence length of the measuring light, interferences generally do not arise. Only in the special case in which the optical path lengths for the light, which is the reference arm 15 has passed through, and the light, which is the measuring arm 13 are substantially the same, arise, based on the mean detected signal intensity, interferential increases and decreases in the detected signal intensity. Around these optical path lengths of the measuring arm 13 and the reference arm 15 to match each other includes the optical delay device 25 a drive 49 to get a distance between the fiber end 26 and the mirror 28 to change, like this by an arrow 50 is indicated.

The measuring arm 13 puts in the in 1 basically three different optical path lengths shown: a first optical path length passes through the previously described measuring light, which from the first Lichtabstrahl- and / or receiving terminal 41 emitted and after interaction with the object 43 from the second light emitting and / or receiving port 45 Will be received. The same optical path length passes through such measuring light, which from the second Lichtabstrahl- and / or receiving terminal 45 emitted and after interaction with the object 43 from the first light emitting and / or receiving port 41 Will be received. A generally different second optical path length passes through such measurement light, which from the first Lichtabstrahl- and / or receiving terminal 41 both emitted and after interaction with the object 43 , is received by this again. One of these in turn generally different optical path length passes through such measuring light, which from the second Lichtabstrahl- and / or receiving terminal 45 both radiated and, after interacting with the object 43 , is received by this again.

Since these three optical path lengths are generally different from each other, by appropriately adjusting the optical delay device 25 be selected, which partial light path of the measuring arm 13 has passed through the measuring light detected as interference.

The illustrated interferometric measuring system operates on the principle of white light interferometry, in which an interference between the measuring light, which has passed through the measuring arm, and the measuring light, which has passed through the reference arm, then occurs when a difference of the optical path lengths of the measuring arm and the reference arm smaller is, for example, a fivefold of the coherence length of the measurement light generated. In the field of Weißlichtinterferometrie several different techniques are known, all of which in the 1 explained interferometric measuring system 1 and also in all other, explained below interferometric measuring systems can be realized. These techniques include time-domain OCT (TD-OCT), in which the optical path length of the reference arm is varied over time by adjusting the optical retarder and that of the detector 33 detected intensity is recorded time-dependent. These techniques also include the Frequency Domain OCT (FD-OCT), in which the spectral composition of the measurement light is examined after the interaction with the object. This can be done according to the principles of Spectral Domain OCT (SD-OCT) and Swept-Source OCT (SS-OCT). In the Spectral Domain OCT, the detector includes 33 a spectrometer in order to spectrally dissect the measurement light to be detected and detect it as a function of the wavelength. Swept source OCT is the light source 3 designed to vary the wavelength of the measuring light generated time-dependent.

In which the 1 explained example contains the reference branch 15 the fiber optic coupler 35 to generated measuring light the photodetector 23 supply. However, this embodiment is optional, ie the fiber optic coupler 35 and the photodetector 23 can be omitted, so that the measuring light of the optical delay device 25 from the fiber optic coupler 7 over the fiberglass 11 is fed directly.

Below are variants of the basis of the 1 described interferometric measuring system described. Are in it. Components which in terms of their structure and / or their function components of the measuring system of 1 provided with the same reference numerals, but supplemented by an additional letter for distinction.

2 shows an example of an ophthalmologic interferometer optical measuring system, which has a similar structure as that with reference to 1 explained interferometric measuring system and also works on the principle of white light interferometry. This includes the measuring system 1a a short coherent light source 3a and a detector 33a which via optical fibers 5a respectively. 31a to a fiber optic coupler 7a are connected. At the fiber optic coupler 7a are also a reference arm 15a of the interferometer with an optical delay device 25a over a fiberglass 11a and a measuring arm 13a of the interferometer over a glass fiber 9a connected. The measuring arm 13a includes a fiber optic coupler 17a to measure light a first Lichtabstrahl- and / or receiving terminal 41a and a second light emitting and / or receiving port 45a for radiation and / or radiated light, which with an object 43a has interacted again, via the two Lichtabstrahl- and / or receiving terminals 41a . 45a to receive and the detector 33a supply. As in the case of the 1 The measuring system described also includes the ophthalmic interferometric measuring system 1a two separate Lichtabstrahl- and / or receiving connections 41a and 45a , These each comprise a fiber end in the illustrated example 61 and a collimation lens 62 ,

The examined object 43a In the example illustrated here is a schematically represented human eye, which is a cornea 65 , an eye lens 66 and a retina 67 includes.

The ophthalmic interferometer optical measuring system explained here 1a differs from that based on the 1 explained measuring system essentially in that in the partial light paths between the first Lichtabstrahl- and / or receiving terminal 41a and the object 43a and between the second light emitting and / or receiving port 45a and the object 43a additional optical components are inserted to manipulate the light differently on these light paths, as will be explained in detail below.

In the light path between the first Lichtabstrahl- and / or receiving terminal 41a and the object 43a are in the beam path behind the other two deflecting mirrors 69 and 71 arranged, each about a pivot axis 70 respectively. 72 are pivotable, as indicated by arrows 73 is indicated. Here are the pivot axes 70 and 72 the two mirrors 69 and 71 oriented to each other such that of the first Lichtabstrahl- and / or receiving terminal 41a radiated light after passing through the two mirrors 69 and 71 is deflectable in two independent directions. That of the first Lichtabstrahl- and / or receiving terminal 41a radiated light hits after reflection at the two mirrors 69 and 71 on a half-transparent mirror 75 at which it is reflected and from the eye lens 66 on the retina 67 at a measuring location 77 is focused. Light, which is in the tissue of the retina 67 is scattered, may be out of sight 43 emerge at the partially transmissive mirror 75 and the pivoting mirrors 71 and 69 be reflected and from the first Lichtabstrahl- and / or receiving terminal 41a received and fed into the interferometer. If the delay device 25a Now set so that the optical path length of the reference arm 15a the optical path length of the measuring arm 13a via the first light emission and / or reception connection 41a to the measuring location 77a and from this again back via the first Lichtabstrahl- and / or receiving terminal 41a can operate by operating the interferometer as a white light interferometer at each measurement location 77 a depth profile of scattering intensities of the retina 67 be won. By appropriate adjustment of the mirror 69 and 71 is it then possible to continue the measuring location? 77 over an extended area of the retina 67 to relocate and acquire such depth profiles at each of these locations so that finally an optical coherence tomogram of an extended volume range of the retina is obtained.

In the partial light path between the eye 43a and the second light emitting and / or receiving port 45a is a selector assembly 81 arranged, which is configured to only a partial cross-section 83 of an overall cross-section 85 of the eye 43a towards the second light emitting and receiving port 45a to let the passing beam of measuring light pass. For this purpose, the selector arrangement comprises 81 a plate 87 with an opening 89 whose diameter is smaller than the diameter of the measuring light beam 85 which of the eye 43a goes out and from the second Lichtabstrahl- and / or receiving terminal 45a can be received. The selector arrangement 81 also includes a drive 91 to relocate the plate 87 transverse to the beam direction, as indicated by an arrow 92 in 2 is indicated, leaving a position of the opening 89 relative to the cross section 85 of the beam and thus a position of the partial cross-section 83 relative to the total cross section 85 is adjustable. This can be the opening 89 may be displaceable only in a linear direction, or it may be displaceable and / or rotatable in two linearly independent directions to the position of the opening 89 within the total cross section of the jet 85 to vary.

With the help of the selector arrangement 81 is it possible with the interferometer optical measuring system 1a the refractive error of the eye 43a to eat. For this the mirrors become 69 and 71 so set that from the light emitting and receiving ports 41a radiated light to a location 77 which is focused, for example, in the center of the retina 67 is arranged. The optical delay device 25a is set so that the optical path length of the reference arm 15a equal to the optical path length of the measuring arm 13a is when the measuring light, the partial light paths between the two different Lichtabstrahl- and / or receiving terminals 41a and 45a passes, that is, for example, when measuring light from the first Lichtabstrahl- and / or receiving terminal 41a to the eye 43a is emitted and from the second Lichtabstrahl- and / or receiving terminal 45a Will be received. Then, for various settings of the selector arrangement 81 each recorded a white light interferogram. From the interferograms the refractive error of the eye can be determined.

This method is described below with reference to 3a . 3b and 3c explained. 3a shows the eye 43a with his eye lens 66 and the cornea 65 , As explained above, at the measuring location 77 Measuring light focused, which of the light source 3a was generated. The retina scatters this light, its wavefronts 101 essentially spherical shape, as they are from a very small, substantially point-shaped area 77 on the retina 67 out. In a normal-sighted emmetropic eye, these wavefronts interact with the lens of the eye 66 and the cornea 65 as essentially plane wave fronts out of the eye. Is the eye 43a not normal-sighted, the wavefronts of the light emerging from the eye are deformed, and that is because three examples are shown in FIG 3a shown light beams 103 ₁ , 103 ₂ and 103 ₃ , which at different angles from the place 77 on the retina 67 go out, go through different optical paths with different optical path lengths. However, optical path lengths can be achieved with the interferometric measuring system 1a be determined very accurately according to the principle of white light interferometry. These different optical path lengths for the three beams 103 ₁ , 103 ₂ and 103 ₃ are each determined by the opening 89 the selector arrangement 81 relative to the entire beam cross section 85 is moved in succession in three positions, as shown by the three representations 89 ₁ , 89 ₂ and 89 _{3 of} the opening in 3a is shown. In each of the three positions of the opening 89 a white light interferogram is recorded. 3b schematically shows the corresponding three interferograms 105 ₁ , 105 ₂ and 105 ₃ . The structure of the interferograms is given by the structure and scattering property of the retina. The interferograms each show the dependence of the measured intensity I on the optical path length d. It can be seen that the structures of the interferograms are the same in each case, with respect to a straight line 104 are aligned and occur at a same optical path length d.

3c shows a corresponding measurement for a myopic myopic eye. Here it can be seen that the three measured interferograms are displaced in the direction of the optical path length relative to one another and with respect to a curved line 106 are aligned. This curved line 106 corresponds to the deformed wavefronts of emerging from the eye measuring radiation. This makes it possible to choose from the three interferograms 105 ₁ , 105 ₂ and 105 _{3 to determine} the curvature of the light emitted from the eye wavefronts of the measuring light. From this curvature in turn it is possible to determine the refractive error of the eye.

4 shows a surgical microscope 111 into which an interferometer-optical measuring system 1b is integrated. The interferometer-optical measuring system 1b has a similar structure as the above with reference to the 1 and 2 explained measuring systems and is only partially shown. Even though these components are in 4 are not shown, has the interferometer-optical measuring system 1b a source of short coherent light, a detector, an optical delay and corresponding beam splitters to pass over two optical fibers 37b and 39b and two light emitting and / or receiving ports 41b and 45b , what a 4 Shown are light towards an object 43b to radiate and to receive from this outgoing light again.

The surgical microscope 111 includes an objective lens 113 in their focal plane 115 an object to be imaged can be arranged. The object plane 115 is from the objective lens 113 mapped to infinity. In the beam path behind the objective lens 113 there is an eyepiece 117 in which an observer can take a look with his eye, to an enlarged image of the object plane 115 perceive. Next to the eyepiece 117 is located in the beam path behind the objective lens 113 a camera 119 to a digital magnified image of the object plane 115 take. In the beam path between the objective lens 113 and the eyepiece 117 or the camera 119 is a zoom system 121 arranged to give a total magnification of the microscope 111 adjust. In the illustrated example, the object to be examined is again a human eye 43b with eye lens 66b and retina 67b , and it's supposed to be the retina 67b of the eye through the microscope 111 be imaged. This is in front of the eye 43b an ophthalmoscope lens 123 arranged to be in the object plane 115 to create an intermediate image of the retina such that this intermediate image with the microscope 111 can be observed.

The interferometer-optical measuring system 1b is in the microscope 111 integrated such that the two Lichtabstrahl- and / or receiving terminals 41b and 45b above the objective lens 113 are arranged so that the objective lens 113 in the beam path between, the first Lichtabstrahl- and receiving terminal 41b and the object plane 115 and in the beam path between the object plane 115 and the second light emitting and / or receiving port 45b is arranged.

A semitransparent mirror 75b is in turn provided to the beam paths between the first Lichtabstrahl- and receiving terminal 41b and the object plane 115 and between the object plane 115 and the second light emitting and / or receiving port 45b partially bring to overlay. In the areas in which these beam paths are not superposed with each other, ie between the first Lichtabstrahl- and / or receiving terminal 41b and the partially transmissive mirror 75b and between the partially transmissive mirror 75b and the second light emitting and / or receiving port 45b are in the in 4 illustrated embodiment, no further optical components arranged. However, it is possible to arrange further optical components in these areas in order to manipulate the two partial light paths differently. For example, deflecting mirrors can be arranged in one of the partial light paths in order to shift the location at which measuring light impinges on the object in the lateral direction, as is the case with the two scanning mirrors 69 and 71 in 2 was explained. The further optical component can, for example, also be a selector arrangement which is configured to allow only a partial cross section of an overall cross section of the beam path to pass, as can be seen from the displaceable plate 87 and opening 89 in 2 was explained.

5 shows a further embodiment of a selector arrangement 81c , which is configured to only a partial cross-section 83c a total cross-section 85c to let pass a ray path. For this purpose, the selector arrangement comprises 81c again a panel 87c with an opening 89c , which is the diameter of the partial cross-section 83c equivalent. In the beam path in front of the panel 87 are two mirrors 121 and 123 arranged, each one point 125 in two independent directions by means of an actuator 127 are pivotable. In the position shown by solid lines of the mirror 121 and 123 is a partial cross-section shown by solid lines 83c of the total cross section 85c selected to be in the fiber end 61c the fiberglass 39c to be coupled. With dashed lines are in 5 one with 121 ' designated position of a pivoting mirror and a with 123 ' designated position of the other pivoting mirror shown, which lead to a partial cross-section shown with dashed lines 83c ' in the glass fiber 39c is coupled. The partial cross sections 83c and 83c ' differ in their position relative to the total cross-section 85c , This makes it possible by controlling the actuators 127 the mirror 121 and 123 to selectively adjust the position of the partial cross section of the total cross section of the available measuring light fed into the interferometer.

6 shows an example of an ophthalmologic interferometer optical measuring system, which has a similar construction, as the basis of the 1 and 2 explained interferometric measuring systems and also works on the principle of white light interferometry. This includes the measuring system 1d a short coherent light source 3d which via optical fibers 5d to a fiber optic coupler 7d connected. At the fiber optic coupler 7d are also a reference arm 15a of the interferometer with an optical delay device 25d over a fiberglass 11d and a measuring arm 13d of the interferometer over a glass fiber 37d connected. The measuring arm 13d includes a first partial light path 12d a second partial light path 14d ,

In the first partial light path 12d is one to the fiber 37d connected first Lichtabstrahl- and / or receiving terminal 41d for the emission of measuring light towards an object 43d and for receiving from the object 43d returning measuring light, which with an object 43a has interacted. This measuring light is in the glass fiber 37d coupled from the beam splitter into the glass fiber 9d transmitted through this the beam splitter 17d fed into the glass fiber 31d transmitted and the detector 33d fed. This measuring light is at the detector with a suitable setting by the delay device 25 superimposed in a first mode of operation provided optical path length with reference light, which is the reference branch 15d has gone through. In this first operating mode, for example, a tomogram of the retina 67d of the eye 43d be included by a place 77d on the retina 67d on which the measuring light is directed, by means of mirrors 71d and 69d , as described above, is scanned and an interferogram is taken for each scanned location.

In the second partial light path 14d is a second Lichtabstrahl- and / or receiving terminal 45d for receiving from the object 43d arranged back measuring light, which the measuring light in a glass fiber 39 coupled and over the beam splitter 17d also the detector 33d supplies. At a suitable setting by the delay device 25 in a second operating mode provided optical path length is measuring light, which is the reference branch 15d has passed through interfering superimposed with measuring light, which in the measuring branch 13d successively the first part-light path 13d and the second partial light path 14d has gone through. The second partial light path 14d includes a selector assembly 81d , The selector arrangement 81d includes a plate 87d , with an opening 89d which by a drive 91d in one by an arrow 92 represented direction transversely to the beam of measuring light coming back from the object is displaceable. By the selector arrangement is only a partial cross-section 83d of the total cross section 85d the beam of measurement light returning from the object into the second light emission and / or reception port 45d in the glass fiber 39d coupled and thus at the detector 33d detected. Here, the second Lichtabstrahl- and / or receiving terminal 45d with the plate 87d connected and shared with this by the drive 91d in the direction 92d relocated. However, there are also other embodiments of the selector arrangement 81d conceivable, such as an embodiment as they are based on the 2 was explained, or was an embodiment, as based on the 5 was explained. As already stated above with reference to 2 and 3 it is explained with the help of the selector arrangement 81d possible, the refractive error of the eye 43d to eat.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102009037841 A1 [0002]
• US 2011/0176142 A1 [0003]

Claims (14)

Interferometer optical measuring system comprising: a light source ( 3 ); a detector ( 33 ); an optical delay device ( 25 ); a first light emitting and / or receiving connection ( 41 ); a second light emitting and / or receiving connection ( 45 ); and a first beam splitter ( 7 ); and a second beam splitter ( 17 ); wherein the first beam splitter ( 7 ) in a light path from the light source ( 3 ) to the optical delay device ( 25 ) is arranged; wherein the first beam splitter ( 7 ) in a light path from the light source ( 3 ) to the first light emitting and / or receiving terminal ( 41 ) is arranged; wherein the first beam splitter ( 7 ) in a light path from the first light emitting and / or receiving port ( 41 ) to the detector ( 33 ) is arranged; wherein the first beam splitter ( 7 ) in a light path from the optical delay device ( 25 ) to the detector ( 33 ) is arranged; wherein the second beam splitter ( 17 ) in a light path from the first light emitting and / or receiving port ( 41 ) to the detector ( 33 ) is arranged; and wherein the second beam splitter ( 17 ) in a light path from the second light emitting and / or receiving port ( 45 ) to the detector ( 33 ) is arranged. Interferometer-optical measuring system according to claim 1, wherein the second beam splitter ( 17 ) in a light path from the first beam splitter ( 7 ) is arranged to the detector. Interferometer-optical measuring system according to claim 1 or 2, wherein the first Lichtabstrahl- and / or receiving terminal and the second Lichtabstrahl- and / or receiving terminal are each configured and oriented to direct measuring light generated by the light source to a same location and / or wherein the first Lichtabstrahl- and / or receiving terminal and the second Lichtabstrahl- and / or receiving terminal are each configured and oriented to receive emanating from a same measurement location measuring light. Interferometer-optical measuring system according to one of claims 1 to 3, further comprising at least one further optical component, which is arranged in a beam path between the first Lichtabstrahl- and / or receiving terminal and a measuring location, and wherein the at least one further optical component, the first Lichtabstrahl- and receiving terminal and the second light emitting and receiving terminal are respectively configured and oriented to direct measuring light generated by the light source to the measuring site. An interferometric optical measuring system according to claim 4, wherein a difference between an optical path length of a beam path from the measurement location on the first Lichtabstrahl- and receiving port to the detector and an optical path length of a beam path from the measurement location on the second Lichtabstrahl- and / or receiving terminal to the detector larger is a coherence length of the measurement light generated by the light source. An interferometric optical measuring system according to claim 5, wherein the optical delay means is configured to have an optical path length of a beam path from the light source through the optical retarder and to the detector optionally to an optical path length from the light source via the first light emitting and / or receiving port to the measuring location and from the measurement location via the first light emission and / or reception connection to the detector or an optical path length from the light source via the first light emission and / or reception connection to the measurement location and from the measurement location via the second light emission and / or reception connection to the detector Set detector. Interferometer-optical measuring system according to one of claims 4 to 6, wherein the at least one further optical component comprises a partially transmissive mirror, which is traversed by the beam path between the measuring location and the second Lichtabstrahl- and / or receiving terminal and at which the beam path between the first Lichtabstrahl- and / or receiving terminal and the measuring location is reflected. Interferometer optical measuring system according to one of claims 4 to 7, wherein the at least one further optical component comprises a beam deflection system for the beam path between the first Lichtabstrahl- and / or receiving terminal and the measuring location. Interferometer-optical measuring system according to claim 8, wherein the beam deflection system comprises two mirrors, which are each pivotable about at least one pivot axis. The interferometric optical measuring system of claim 1, further comprising a selector assembly configured to pass only a partial cross section of an overall cross section of a beam path toward the second light emitting and / or receiving port, a position of the partial cross section relative to the overall cross section is adjustable. Interferometer optical measuring system according to claim 10, wherein the selector assembly comprises two mirrors, which are each pivotable about two pivot axes. Use of the interferometer-optical measuring system according to one of claims 1 to 11 for measuring a refractive error of an eye. Surgical microscope comprising: a lens; an eyepiece and / or an image sensor; and an interferometer-optical measuring system according to any one of claims 1 to 11, wherein an imaging beam path of the microscope, which extends from an object through the objective to the eyepiece or the image sensor, and a measurement beam path of the ophthalmologic interferometric measurement system which extends from the object to the first and / or the second light emission and / or receiving terminal extends, at least partially overlaid. A method for measuring a refractive error of an eye, comprising: Generating measuring light with a light source; Recording a plurality of interferences between a first part of the measuring light and a second part of the measuring light with a detector, Wherein the first part of the measurement light passes through a reference light path from the light source through an optical delay device with an adjustable light path to the detector, - Wherein the second part of the measuring light passes through a measuring light path from the light source to the detector, and Wherein the measuring light path comprises a first partial light path from the light source to a cornea of the eye and a second partial light path from the cornea to the detector, Blocking a portion of the measuring light in the second partial light path such that only a partial cross section of the entire beam cross section is not blocked and can pass through the measuring light path, for several different position of the partial cross section relative to the entire beam cross section; wherein during the recording of different interferences different partial cross sections of the entire beam cross section are not blocked; and wherein the method further comprises: Determining the ametropia based on the plurality of recorded interferences and positions of the partial cross sections not blocked during the recording of the respective interferences relative to the total beam cross section.

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