WO2017036893A1

WO2017036893A1 - Image recording arrangement, optical observation appliance and method for recording images

Info

Publication number: WO2017036893A1
Application number: PCT/EP2016/070023
Authority: WO
Inventors: Roland Guckler
Original assignee: Carl Zeiss Meditec Ag
Priority date: 2015-08-31
Filing date: 2016-08-24
Publication date: 2017-03-09
Also published as: DE102016104439A1

Abstract

An image recording arrangement (1) is provided. It is equipped with – a light-source arrangement (13) for emitting light comprising visible light (11) and excitation light (10) for exciting an infrared emission in an observation object (4), – a recording device (3) comprising an image sensor for recording an image of an observation object (4) irradiated by the light of the light-source arrangement (13), and – a recording filter (9) arranged between the observation object (4) and the image sensor of the recording device (3), the transmission characteristics of said recording filter being configured in such a way that it allows visible light (16) reflected by the observation object (4) and infrared light (12) emitted by the observation object (4) to pass but blocks excitation light (10) reflected by the observation object (4). The light-source arrangement (13) is adjustable in such a way that it emits only visible light (11) or only excitation light (10) in the direction of the observation object (4).

Description

An imaging device, an optical observation device, and a method of capturing images

The invention relates to an image pickup device and an optical observation device with an image pickup device. In addition, the invention relates to methods for capturing images in the visible spectral range and infrared images of an observation object.

In the medical field contrast agent / indicator substances are often used to visualize processes and conditions in the body, which are not or only insufficiently recognizable by the use of visible light (white light) alone. Suitable indicator substances are, in particular, fluorescent dyes, such as, for example, indocyanine green (ICG). When indocyanine green is irradiated with light in the near-infrared spectral range of about 600 nm to about 900 nm (absorption spectrum), indocyanine green fluoresces by emitting light in the near-infrared spectral range of about 750 nm to about 950 nm (fluorescence spectrum). The light emitted by indocyanine green light can be detected by a near infrared light sensitive camera. Since indocyanine green has the ability to bind to plasma proteins, the intravascular administration of indocyanine green into the bloodstream allows the perfusion of tissues and organs to be assessed using near-infrared light images (see, for example, https://de.wikipedia.org/ wi ki / indocyanine green).

However, existing surgical microscopes often have only one camera with an infrared blocking filter, so that only visible light or white light can hit the camera. Therefore, for capturing fluorescent indocyanine green, either an additional camera with an infrared-transmitting filter or a camera without an infrared-blocking filter would have to be retrofitted with an upstream filter wheel with an infrared light-transmitting filter and an infrared-blocking filter. However, this would mean that either in addition to the surgical microscope another device would have to be used, namely an additional camera with a filter passing through infrared light, or that an existing surgical microscope would have to be rebuilt and equipped with a larger head / image pickup area, in which the additional camera or find the filter wheel upstream of the camera.

From the patent application US 2008/0251 694 A1 an image recording device for the medical field is known, with which an image can be taken, in which an image in the visible spectral range is combined with a image in the infrared spectral range. The image pickup device has a first visible light source and a second light source for exciting a fluorescent substance in the infrared. Light from both light sources strikes the object to be examined, provided with a fluorescent substance. To record an image object, a CCD light sensor is present, preceded by a filter which blocks the light for exciting the infrared light fluorescent substance and allows light emitted by the object to pass in the visible wavelength range and in the infrared light range. In order to emphasize the infrared light emitted by the object in the recorded image with respect to the emitted visible light, the filter has a significantly lower transmission in the visible spectral range than in the near-infrared spectral range. This results in a composite image in which there is a good balance between the image in the visible spectral region and the image in the near infrared spectral region.

It is a first object of the invention to provide an image recording arrangement with which advantageously an infrared image or an image in the visible spectral range of an observation object can be set up. can be taken. It is a second object of the invention to provide an optical observation apparatus with which advantageously an infrared image or an image in the visible spectral range can be recorded by an observation object. A third object of the invention is to provide an advantageous method for capturing images in the visible spectral range and of infrared images from an observation object.

The first object is achieved by an image recording device having the features of claim 1, the second object by an optical observation device having the features of claim 11. The third object is achieved by a method for capturing images in the visible spectral range and infrared images according to claim 14. The dependent claims contain advantageous embodiments of the invention.

An imaging arrangement according to the invention comprises a light source arrangement for emitting light, which comprises visible light and excitation light for exciting an infrared emission in an observation object. The visible light here may be white light in particular.

Furthermore, the image recording arrangement according to the invention comprises a recording device with an image sensor for recording an image of an observation object irradiated with the light of the light source arrangement and a recording filter arranged or to be arranged between the observation object and the recording device whose transmission characteristic is designed such that it reflects visible light reflected from the observation object Infrared light emitted by the observation object passes, however, the excitation light reflected by the observation object is blocked. In particular, the transmission characteristic of the recording filter can be chosen such that it allows light to pass in a wavelength range from 400 nm to 700 nm and in a wavelength range from 800 nm to 950 nm and blocks light in a wavelength range from 700 nm to 800 nm. In addition, the light source arrangement is adjustable so that it emits either only visible light or only excitation light in the direction of the observation object.

In a first variant, the light source arrangement comprises a light source emitting both visible light and excitation light and a filter changer which is arranged or to be arranged between the light source and the observation object and which is equipped at least with a first filter and a second filter. The first filter has a first filter characteristic which allows only the visible light to pass, the second filter a second filter characteristic which allows only the excitation light to pass. In this case, it is advantageous if the spectrum of the light emitted by the light source extends at least over the spectral range from 400 nm to 800 nm. By means of the filter changer, the light source arrangement can thus be adjusted such that it emits either only visible light or only excitation light in the direction of the observation object. As the light source in this case, for example, a xenon lamp or a halogen incandescent lamp can be used in the light source arrangement. The first filter characteristic may in particular be selected such that the first filter only allows light to pass in a wavelength range of 400 nm to 700 nm, and the second filter characteristic may be selected such that the second filter only light in a wavelength range of 700 nm to 800 nm can happen. The filter changer can be designed, for example, as a filter wheel, as a slide, as a pivotable filter carrier, etc. However, other embodiments are also possible.

In a second variant, the light source arrangement comprises an only visible light-emitting first light source, a light source only excitation light and a switching device, wherein the switching device makes it possible to operate the light source arrangement either only with the first light source or only with the second light source. By means of the switching device, the light source arrangement can thus be adjusted such that it emits either only visible light or only excitation light in the direction of the observation object. The first In this case, the light source can in particular be designed such that it emits only light in a wavelength range from 400 nm to 700 nm, and the second light source can be configured in particular such that it emits only light in a wavelength range from 700 nm to 800 nm. For example, neutral-white or day-white light-emitting lamps such as LED lamps or metal halide lamps which are obtainable with low emission in the spectral range above 700 nm, ie in the near infrared, are suitable as the first light source. For example, an excitation light-emitting LED or an excitation light-emitting laser diode can be used as the second light source.

As a recording device can, for example, in the context of the image recording device according to the invention, a standard camera in which the standard built-infrared filter is replaced by the recording filter described, use.

With the image recording arrangement according to the invention, the method according to the invention for taking pictures of an observation object in the visible spectral range and of infrared images of the observation object can be carried out. In this method, the observation object is illuminated exclusively with visible light, ie, light in the visible spectral region, when an image is to be recorded in the visible spectral region, and exclusively with an excitation light for exciting an infrared emission in the observation object when an image is acquired in the infrared spectral region should. For example, a light source for emitting light which emits the visible light and the excitation light for exciting an infrared emission in an observation object can be used as the light source. For irradiating the observation object exclusively with visible light, the first filter between the light source and the observation object can then be arranged, which allows only the visible light to pass, and for irradiating the observation object exclusively with excitation light, the second filter, which allows only the excitation light to pass. Alternatively, an only visible light-emitting first light source and an excitation light-emitting light source may be used. In this case For illuminating the observation object, only the first light source is operated exclusively with the visible light, and only the second light source for illuminating the observation object exclusively with the excitation light. The reaching to the image sensor of the recording light light is blocked before reaching the image sensor with a recording filter whose transmission characteristic is such that it allows reflected by the observation object visible light and emitted by the observation object infrared light passes, however, blocked by the observation object excitation light blocked.

The fact that in the image recording arrangement according to the invention or in the method according to the invention the visible light or the excitation light on the side of the light source is separated from infrared light outside the spectral range of the excitation light, and in that the excitation light is blocked by the recording filter, it becomes possible for recording fluorescence images in the infrared spectral range and for recording images in the visible spectral range on the side of the image sensor of the recording device to use only a single filter, so that a filter wheel in front of the camera or the use of two cameras is not necessary. The image recording device according to the invention therefore requires only little space in the region of the receiving device. This is particularly advantageous if the image recording device is to be used, for example, in a surgical microscope or an endoscope, where a second camera or a filter changer in front of the camera would require additional volume in the area of the observation beam path of the surgical microscope and thus to restrictions on the freedom of movement of the patient Doctor could lead. On the other hand, arranging a filter changer between the light source and the surgical site is generally less troublesome because the light source - and thus also the filter changer - can usually be arranged at a greater distance from the surgical site than the observation optics of the surgical microscope or the endoscope.

In the image recording arrangement according to the invention, the transmission characteristic of the recording filter can be selected such that the transparency mission for the reflected light from the observation object not more than 10%, in particular not more than 5%, differs from the transmission for the infrared light emitted by the observation object. In this case, the transmission characteristic of the recording filter can be selected such that the transmission for the visible light reflected from the observation object and the transmission for the infrared light emitted by the observation object are in each case at least 80% and preferably in each case at least 90%. In this way, with a total high degree of transmission of at least 80%, preferably of at least 90%, a high sensitivity of the recording device can be realized both in the visible spectral range and in the infrared spectral range.

An optical observation device according to the invention, which can be configured in particular as a surgical microscope or as an endoscope, is equipped with an image recording device according to the invention. In a specific embodiment, the optical observation device may comprise imaging optics which generate at least one image of the observation object and in which an image sensor is arranged at the location of the image of the observation object, the imaging optics then forming the recording device together with the image sensor.

Other features, characteristics and advantages of the present invention may become apparent from the following description with reference to the accompanying drawings.

Figure 1 shows a schematic representation of a first

Embodiment of the invention

Image recording arrangement when taking an infrared image.

Figure 2 shows a schematic representation of the first

Embodiment when taking a color image.

Figure 3 shows the transmission characteristics of the first embodiment

Embodiment used first filter and the second filter used in the first embodiment (above) and the recording filter (below), the transmission being shown as a function of the wavelength.

FIG. 4 shows a schematic representation of a second one

Embodiment of the invention

Image recording arrangement when taking an infrared image.

Figure 5 shows a schematic representation of the second

Embodiment when taking a color image.

FIG. 6 shows an example of the basic structure of a

Operating microscope with infinite beam path in a schematic representation.

In the figures, like reference numerals designate like or equivalent components.

Figures 1 and 2 show an image pickup device 1 according to the invention with a light source assembly 13 and a camera 3 as a recording device. The light source arrangement 13 of the exemplary embodiment comprises a light source 2, which in the present exemplary embodiment is a xenon lamp. As such, it is a broadband light source which in operation emits both white light 1 1 in the visible spectral range and light with a spectrum for exciting an infrared fluorescence in an observation object 4, hereinafter referred to as excitation light 10. The spectrum of the xenon lamp 2 comprises a spectral range from 400 nm to 900 nm, the white light 1 1 corresponding to the spectral range from 400 nm to 700 nm and the excitation light 10 in the present exemplary embodiment to the wavelength range from 700 nm to 900 nm. Thus, the light source 2 is particularly suitable for exciting the fluorescence in an observation object 4 containing indocyanine green. Indocyanine green is often used as a contrast agent in the medical field to visualize tissue vessel conditions unrecognizable by visible light. Indocyanine green absorbs light in the wavelength range from 600 nm to 900 nm and emits fluorescence radiation from 750 nm to 950 nm, ie in a section of the near-infrared wavelength range. With excitation in the wavelength range from 700 nm to 800 nm, therefore, fluorescence can be observed with indocyanine green provided object areas in the wavelength range above 800 nm.

With the light source 2 of the light source arrangement 13, an observation object 4, for example an operating area, is illuminated during operation of the image recording arrangement 1. In this case, the light source 2 may be arranged at a sufficient distance to the observation object 4, for example, not to hinder an operation. In particular, the light source 2 can be arranged away from the observation object 4, in which case the light of the light source is, for example, passed via an optical waveguide to the observation object 4 or to an illumination optical unit (not shown) located in the vicinity of the observation object 4.

The light source arrangement 13 also comprises a filter changer 5 which is arranged or to be arranged between the light source 2 and the observation object 4 and which is designed as a filter wheel in the present exemplary embodiment but can also be formed by any other filter changer. Preferably, the filter wheel 5 is arranged in the vicinity of the light source 2. If the filter wheel or the filter changing device is not fixedly arranged between the light source 2 and the observation object 4, it or it can be introduced between the light source 2 and the observation object 4, for example. Swiveling or insertable, be configured. The filter wheel 5 comprises a first filter 6 and a second filter 7 and is rotatably or adjustably arranged in the beam path of the light source 2, that the outgoing light from the light source 2 either only the first filter 6 or only the second filter 7 passes. In the present exemplary embodiment, the first filter 6 has a transmission characteristic such that only light in a wavelength range from 400 nm to 700 nm can pass through it (see FIG. 3, top diagram). In other words, the first filter 6 allows only the white light 1 1 emitted by the light source 2 to pass in the visible spectral range and blocks all light with wavelengths greater than 700 nm, that is to say that also emitted by the light source 2 Excitation light 10. In the present embodiment, however, the second filter 7 has such a transmission characteristic that only light in a wavelength range from 700 nm to 800 nm can pass it (see FIG. 3, top diagram). In other words, the second filter 7 allows only the excitation light emitted by the light source 2 pass through 10 and blocked by the light source 2 also emitted white light 1 1 in the visible spectral range and all light with wavelengths greater than 800 nm. With the help of the filter changer 5 can Observation object 4 so either only with white light 1 1 in the visible spectral range or only with excitation light 10 are illuminated.

The camera 3 of the image recording device 1 is directed onto the observation object 4 and serves to capture an image of the observation object 4 illuminated by the light of the light source 2. For capturing the image, the camera 3 comprises at least one image sensor, for example a CCD sensor or a CMOS sensor. The camera 3 is preceded by a recording filter 9, which is arranged between the observation object 4 and the image sensor camera 3. In this case, the recording filter can be integrated into the camera 3 and, for example, be located directly in front of the image sensor, or it can be connected upstream of the camera 3. In the present exemplary embodiment, the recording filter 9 has a transmission characteristic such that only light in the wavelength ranges from 400 nm to 700 nm and from 830 nm to 900 nm can pass it (see FIG. 3, bottom diagram). Light with other wavelengths, in particular excitation light is blocked by the recording filter 9, however.

FIG. 1 shows the image recording device 1 according to the invention in the infrared light mode, in which, for example, an image of fluorescent indocyanine green is recorded in the observation object 4. In this mode, the filter changer 5 is in a position in which the second filter 7 is located in the illumination beam path of the light source 2, whereas the first filter 6 is located outside the illumination beam path. Only the excitation light 10 is transmitted by the second filter 7, whereas the white light 1 1 in the visible spectral range and light with wavelengths above 800 nm are blocked. The observation object 4 therefore becomes illuminated exclusively with the excitation light to excite the fluorescence in Indocyaningrün. Accordingly, indocyanine green present in the observation object 4 emits infrared light in the range from 750 nm to 950 nm, from which light passes in the wavelength range from 830 nm to 900 nm onto the image sensor of the camera 3 via the recording filter 9. The recording filter 9 thus allows light 12 to pass from the fluorescence spectrum of indocyanine green to the camera 3 and blocks the excitation light 14 reflected by the observation object 4. In the infrared light mode, the camera 3 thus captures an infrared light image of the fluorescence in the observation object 4. Because the recording filter 9 blocks the reflected excitation light 14, only those wavelengths which are contained in the fluorescence spectrum but not in the absorption spectrum of indocyanine green impinge on the camera, so that the infrared image is not influenced by the reflected excitation light 14. This is particularly relevant when using indocyanine green, since the absorption spectrum and the fluorescence spectrum of indocyanine green partly overlap. Any scattered light in the visible spectral range reflected by the observation object 4 can likewise pass through the recording filter 9 because of its transmission characteristic. The scattered light can therefore be used in the medical field of application for the simultaneous detection and / or presentation of anatomical structures in the visible spectral range and of fluorescent structures.

FIG. 2 shows the image recording device 1 according to the invention in white-light mode, in which an image is recorded in the visible spectral range. In this mode, the filter changer 5 is in a position in which the first filter 6 is located in the illumination beam path of the light source 2, whereas the first filter 7 is outside the illumination beam path. Only the visible light 1 1 is transmitted by the first filter 6, whereas the excitation light 10 and light having wavelengths above 800 nm are blocked. The observation object 4 is therefore illuminated exclusively with white light in the visible spectral range. Correspondingly, the observation object 4 reflects white light 16 in the range from 400 nm to 700 nm, which reaches the image sensor of the camera 3 via the recording filter 9. in the White light mode takes the camera 3 thus a color image of the observation object 4, due to the transmission characteristic of the first filter 6 no infrared light, but only white light to the observation object 4 - and thus no reflected infrared light, but only reflected white light 1 6 reaches the camera 3 -, so that an infrared cut filter in the camera is not necessary. In the white light mode, therefore, the camera 3 in the medical field of application, in particular, detects the anatomical structures of the observation object 4.

The camera 3 may be assigned an evaluation device (not shown) for evaluating the recorded images, in particular recorded infrared images. The evaluation unit can be designed, for example, such that it recognizes certain vessels and in particular deviations from a normal state of the vessels. Furthermore, the camera 3 can be assigned a display module or display 8, which displays the camera image before and / or after the evaluation by the evaluation device. In addition to the display module 8, the camera 3 can also be assigned a recording module (not shown) which records the recorded images and / or the results of the evaluation unit.

Figures 4 and 5 show a second embodiment of an image pickup device according to the invention. Elements of the second embodiment which do not differ from elements of the first embodiment are indicated in Figures 4 and 5 by the same reference numerals as in Figures 1 and 2 and will not be explained again to avoid repetition. In the following, therefore, only the differences between the two exemplary embodiments will be discussed.

The second embodiment differs from the first embodiment in the embodiment of the light source assembly 13. Instead of a xenon lamp and a filter wheel, the light source assembly 13 in the second embodiment comprises a slide 19 with two lamps 17, 18, which optionally the starting point of Illumination beam path can form. The first lamp 17 is in the present embodiment, a metal halide lamp which is designed such that it emits visible light 1 1, but little or no excitation light 10 in the near-infrared spectral range above 700 nm. In particular, the first lamp 17 in the spectral range from 400 nm to 700 nm emit. Such emission characteristics can be met, for example, by daylight-white or neutral-white light-emitting metal halide lamps. In the present exemplary embodiment, the second lamp is a light source which exclusively emits excitation light 10 (for example in the near infrared). In particular, it may be a near infrared emitting LED or a near infrared emitting laser diode emitting in the spectral range between 700 nm and 800 nm. With the aid of the slider 19, either the first light source 17 or the second light source 18 can form the starting point of the illumination beam path for illuminating the observation object 4. The slider 19 thus forms a switching device which makes it possible to operate the light source arrangement 13 either with the first light source 17 or with the second light source 18. However, the switching device does not need to be designed in the form of a slider. It may instead be formed by optical elements such as mirrors, prisms, etc., which make it possible to couple the light of the first light source 17 and the light of the second light source 18 into the illumination beam entrance. By selectively switching on the first light source 17 or the second light source 18, the light source arrangement can then couple the corresponding light into the observation beam path.

FIG. 4 shows the image recording arrangement 1 of the second embodiment in the infrared light mode in which, for example, an image of indocyanine green fluorescent in the observation object 4 is taken. In this mode, the slider 19 is set so that the light source assembly 19 is operated with the second light source 18. Accordingly, the observation object 4 is illuminated exclusively with the excitation light for exciting the fluorescence in the indocyanine green. Accordingly, indocyanine green existing in the observation object 4 emits infrared light in the range of 750 nm to 950 nm, from the light via the recording filter 9 reaches the image sensor of the camera 3 in the wavelength range from 830 nm to 900 nm. The recording filter 9 thus allows light 12 to pass from the fluorescence spectrum of indocyanine green to the camera 3 and blocks the excitation light 14 reflected by the observation object 4. In the infrared light mode, the camera 3 thus captures an infrared light image of the fluorescence in the observation object 4. Any scattered light in the visible spectral range reflected by the observation object 4 can likewise pass through the recording filter 9 because of its transmission characteristic. The scattered light can therefore be used in the medical field of application for the simultaneous detection and / or presentation of anatomical structures in the visible spectral range and of fluorescent structures.

FIG. 5 shows the image recording arrangement 1 of the second exemplary embodiment in the white-light mode, in which an image is recorded in the visible spectral range. In this mode, the slider 19 is set so that the light source assembly 13 is operated with the first light source 17. The observation object 4 is therefore illuminated with light 1 1 in the visible spectral range. Light with wavelengths above 700 nm is substantially not emitted by the first light source 17. The observation object 4 is therefore illuminated exclusively with light in the spectral range up to 700 nm. Correspondingly, the observation object 4 reflects light 16 in the spectral range from 400 nm to 700 nm. Thus, only white light in the range from 400 nm to 700 nm reaches the image sensor of the camera 3 via the recording filter 9. In the white-light mode, the camera 3 thus takes a color image of to the observation object 4.

The image recording device 1 according to the invention can, for example, be part of a surgical microscope. Hereinafter, with reference to FIGS. 4 and 5, a possible structure of a surgical microscope 102 having an image pickup device according to the present invention will be described which serves as an example of an optical observation device having an image pickup device according to the present invention.

The surgical microscope 102 shown in FIG. 6 comprises an objective 105 facing an object field 103. The object field 103 is shown in FIG Focal plane of the lens 105 is arranged so that it is imaged by the lens 105 to infinity. In other words, a divergent ray bundle 107 emanating from the object field 103 is converted into a parallel ray bundle 109 as it passes through the objective 105. Such a beam path is also called infinite beam path.

In FIG. 6, the objective 105 is shown only schematically as an achromatic lens for the sake of simplicity. To reduce the working distance of the surgical microscope 102, i. In order to be able to vary the distance of the object-side focal plane from the underside of the surgical microscope 102 without having to move the surgical microscope 102 itself, an objective lens system comprising a plurality of lenses can be used in an operating microscope 102 embodied according to the invention instead of a simple achromatic lens, with which the operating distance of the surgical microscope 102 varies by varying the focal distance. Such an objective with which the focus distance can be varied is also known as a zoom lens.

Observer side of the lens 105, a magnification changer 1 1 1 is arranged, which can be formed either as in the illustrated embodiment as a zoom system for continuously changing the magnification factor or as a so-called Galilei changer for stepwise change of the magnification factor. In a zoom system, which is constructed, for example, from a combination of lenses with three lenses, the two object-side lenses can be moved to vary the magnification factor. In fact, however, the zoom system can also have more than three lenses, for example four or more lenses, the outer lenses then being able to be fixed. In a Galileo changer, on the other hand, there are several fixed lens combinations that represent different magnification factors and that can be alternately introduced into the beam path. Both a zoom system and a Galilean changer convert an object-side parallel beam into an observer-side parallel beam with a different beam diameter. The magnification changer 1 1 1 is already part of the binocular beam path in the present embodiment of the surgical microscope 102, ie it has its own lens combination for each stereoscopic partial beam path 109A, 109B of the surgical microscope 102. The setting of a magnification factor by means of the magnification changer 1 1 1 takes place in the present embodiment via a motor-driven actuator, which is part of a magnification change unit for adjusting the magnification factor together with the magnification changer 1 1 1.

The observer side of the magnification changer 1 1 1 is followed by an interface arrangement 1 13A, 1 13B, via which external devices can be connected to the surgical microscope 102 and in the present exemplary embodiment comprises beam splitter prisms 15A, 15B. In principle, however, other types of beam splitters may also be used, for example partially transmissive mirrors. The interfaces 1 13A, 1 13B serve in the present embodiment for coupling a beam from the beam path of the operating microscope 102 (beam splitter prism 1 15B) or for coupling a beam in the beam path of the operating microscope 102 (beam splitter prism 1 15A). However, it is also possible to use both interfaces 1 13A, 1 13B for coupling or both interfaces 1 13A, 1 13B for decoupling beams.

In the present exemplary embodiment, the beam splitter prism 15A in the partial beam path 109A serves, with the aid of a display 137, for example a digital mirror device (DMD) or an LCD display, and an associated optics 139, information or data for one via the beam splitter prism 15A Viewer einzubiegeln in the beam path 109A of the surgical microscope 102. In the other partial beam path 109B, a camera adapter 1 19 with a camera 121 attached thereto is arranged on the interface 1 13B, which is equipped with an electronic image sensor 123, for example with a CCD sensor or a CMOS sensor. By means of the camera 121, an electronic and in particular a digital image of the tissue region 103, which represents the observed object field, can be recorded. The camera adapter 19 serves to adapt the imaging optics of the surgical microscope 102 in such a way that an image of the tissue region 103 is formed at the location of the image sensor 123. in the present surgical microscope 102, the camera 121, instead of a conventional infrared blocking filter on a recording filter, as has been described above.

At the interface 1 13, a binocular tube 127 follows observer side. This has two tube lenses 129A, 129B, which focus the respective parallel beam 109A, 109B on an intermediate image plane 131, ie the observation object 103 to the respective intermediate image plane 131 A, 131 B map. The intermediate images located in the intermediate image planes 131 A, 131 B are finally imaged by the eyepiece lenses 135 A, 135 B again to infinity, so that a viewer can view the intermediate image with a relaxed eye. In addition, in the binocular tube by means of a mirror system or by means of prisms 133A, 133B an enlargement of the distance between the two partial beams 109A, 109B, in order to adapt to the eye distance of the observer. With the mirror system or the prisms 133A, 133B, image formation also takes place.

The surgical microscope 102 is also equipped with a lighting device, with which the object field 103 can be illuminated with broadband illumination light. For this purpose, the lighting device in the present embodiment, a white light source 141, such as, for example, a halogen incandescent lamp or a gas discharge lamp, such as a xenon lamp, on. The light emanating from the white light source 141 is directed via a deflection mirror 143 or a deflecting prism in the direction of the object field 103 in order to illuminate it. In the illumination device, there is furthermore an illumination optical system 145, which ensures uniform illumination of the entire observed object field 103. The white light source 141 is associated with a filter changer in the form of a slider 147, which comprises at least the above-described first filter 6 and the second filter 7 described above. By moving the slider 147 in the direction of the double arrow, between a position of the slider 147, in which the first filter 6 is located in the illumination beam path (as shown in Figure 6), and a position the slider 147, in which the second filter 7 is in the illumination beam path, are changed back and forth.

It should be noted that the illumination beam path shown in FIG. 6 is highly schematic and does not necessarily reflect the actual course of the illumination beam path. In principle, the illumination beam path can be embodied as so-called oblique illumination, which comes closest to the schematic illustration in FIG. In such oblique illumination, the beam path extends at a relatively large angle (6 ° or more) to the optical axis of the objective 105 and, as shown in FIG. 6, can extend completely outside the objective 105. Alternatively, however, it is also possible to let the illumination beam path of the oblique illumination pass through an edge region of the objective 105. Another possibility for arranging the illumination beam path is the so-called 0 ° illumination, in which the illumination beam path passes through the objective 105 and between the two partial beam paths 109A, 109B, along the optical axis of the objective 105 in the direction of the object field 103 into the objective 105 is coupled. Finally, it is also possible to carry out the illumination beam path as so-called coaxial illumination, in which a first and a second illumination beam path are present. The two illuminating partial beam paths are coupled into the surgical microscope via one or more beam splitters parallel to the optical axes of the observation partial beam paths 109A, 109B, so that the illumination runs coaxially to the two observation partial beam paths.

With the surgical microscope 102 described, it is possible to selectively record a color image or an infrared image from an observation object located in the object field 103 with only one camera 121, in which the conventionally present infrared cut filter is replaced by the described recording filter, and without filter changer in the region of the camera 121. Prerequisite is only the filter changer 147, with the help between an illumination of the object field 103 only with white light in the visible spectral range and illumination of the object field 103 only with excitation light for Excite a fluorescence back and forth can be changed. The filter changer 147 in the region of the illumination light source 141 is less disturbing than would a filter changer 147 in the region of the camera 121, since the illumination light source 141 can be arranged further from the object field 103 than the camera 121.

The present invention has been described in detail by way of embodiments. The description of the exemplary embodiments serves primarily to illustrate concepts for carrying out the present invention, but not to limit the invention to the specific embodiments shown in the exemplary embodiments. As one skilled in the art will readily appreciate, embodiments of the invention may depart from the illustrated embodiments without departing from the scope of the invention as defined in the appended claims. For example, in an image pickup device as described with reference to FIGS. 1 to 3, instead of xenon lamps, halogen incandescent lamps or other broadband light sources can be used as well as light sources which emit essentially in individual spectral lines. In addition, fluorescent dyes other than the exemplified indocyanine green can be used. Depending on the fluorescent dye used, the wavelength range of the excitation light may be wider or narrower than the wavelength range described with reference to the exemplary embodiments, or it may be shifted with respect to the wavelength range described with reference to the exemplary embodiments. The present invention is therefore intended to be limited only by the claims.

Claims

claims

1 . Image recording arrangement (1) with

a light source arrangement (13) for emitting light which comprises visible light (1 1) and excitation light (10) for exciting an infrared emission in an observation object (4),

a recording device (3) with an image sensor for recording an image of an observation object (4) irradiated with the light of the light source arrangement (13), and

a receiving filter (9) arranged or to be arranged between the observation object (4) and the image sensor of the recording device (3), whose transmission characteristic is designed such that it reflects visible light (1 6) reflected by the observation object (4) and emitted by the observation object (4) Infrared light (12) passes, however, from the observation object (4) reflected excitation light (14) blocked, characterized in that

the light source arrangement (13) is adjustable such that it emits either only visible light (1 1) or only excitation light (10) in the direction of the observation object (4).

2. An image recording arrangement (1) according to claim 1, characterized in that the light source arrangement (13) both a visible light (1 1) and excitation light (10) emitting light source (2) and between the light source (2) and the observation object ( 4) arranged or to be arranged filter changer (5) with at least a first filter (6) and a second filter (7), wherein the first filter (6) has a first filter characteristic that allows only the visible light (1 1) passes, and the second filter (7) has a second filter characteristic that allows only the excitation light (10) to pass.

3. Image recording arrangement (1) according to claim 2, characterized in that the spectrum of the light source (2) extends at least over the spectral range from 400 nm to 800 nm.

4. Image recording device (1) according to claim 2 or claim 3, characterized in that the first filter characteristic is selected such that the first filter (6) only light in a wavelength range of 400 nm to 700 nm happen.

5. Image recording arrangement (1) according to one of claims 2 to 4, characterized in that the second filter characteristic is selected such that the second filter (7) only light in a wavelength range of 700 nm to 800 nm pass.

6. Image recording arrangement (1) according to claim 1, characterized in that the light source arrangement (13) comprises only a first 700 nm emitting first light source (17), only excitation light (10) emitting the second light source (18) and a switching device (19) in that the switching device (19) makes it possible to operate the light source arrangement (13) either only with the first light source (17) or only with the second light source (18).

7. Image recording arrangement (1) according to one of the preceding claims, characterized in that the visible light (1 1) is white light.

8. image recording device (1) according to any one of the preceding claims, characterized in that the transmission characteristic of the recording filter (9) is selected such that it light in a wavelength range of 400 nm to 700 nm and in a wavelength range of 800 nm to 950 nm and blocks light in a wavelength range of 700 nm to 800 nm.

9. Image recording arrangement (1) according to one of the preceding claims, characterized in that the transmission characteristic of the recording filter (9) is selected such that the transmission for the visible light (16) reflected by the observation object (4) differs no more than 10% from the transmission for the infrared light (12) emitted by the observation object (4).

10. An image recording arrangement (1) according to claim 9, characterized in that the transmission characteristic of the recording filter (9) is selected such that the transmission for the observation object (4) reflected visible light (1 6) and the transmission for the observed object ( 4) emitted infrared light (12) each amount to at least 80%.

1 1. An optical observation device (102) having an image pickup device according to any one of the preceding claims.

12. An optical observation device (102) according to claim 1 1, which is designed as a surgical microscope or as an endoscope.

13. An optical observation device (102) according to claim 11 or claim 12, which comprises an imaging optics which generates at least one image of the observation object (103) and in which an image sensor (123) is arranged at the location of the image of the observation object (103) which forms the receiving device together with the imaging optics.

14. A method for capturing images of an observation object (4) in the visible spectral range and infrared images of the observation object (4), in which

the observation object (4) is illuminated exclusively with visible light (1 1) if an image is to be recorded in the visible spectral range, and

the observation object (4) is illuminated exclusively with an excitation light (10) for exciting an infrared emission in the observation object (4) when an image is to be recorded in the infrared spectral range, and the reaching of the image sensor of a receiving device (3) light is filtered before reaching the image sensor with a recording filter (9) whose transmission characteristic is designed such that they visible light (16) reflected by the observation object (4) and emitted by the observation object (4) Infrared light (12) passes, however, from the observation object (4) reflected excitation light (14) blocked.

15. The method according to claim 14, in which

a light source (2) for emitting light comprising the visible light (1 1) and the excitation light (10) is used,

for illuminating the observation object (4) exclusively with the visible light (1 1) a first filter (6) between the light source (2) and the observation object (4) is arranged, which passes only the visible light (1 1), and

for illuminating the observation object (4) exclusively with the excitation light (10) a second filter (7) between the light source (2) and the observation object (4) is arranged, which allows only the excitation light (10) to pass.

16. The method according to claim 15, in which a first filter (6) is used, which passes only light in a wavelength range of 400 nm to 700 nm.

17. The method of claim 15 or claim 1 6, in which a second filter (7) is used which allows only light in a wavelength range of 700 nm to 800 nm to pass.

18. The method according to claim 14, in which

a first light source (17) emitting only visible light (1 1) and a light source (18) emitting only excitation light (10),

for illuminating the observation object (4) only with the visible light (1 1) only the first light source (17) is operated and for illuminating the observation object (4) only the second light source (18) is operated exclusively with the excitation light (10).

19. The method according to any one of claims 14 to 18, in which a recording filter (9) is used, the light in a wavelength range of 400 nm to 700 nm and light in a wavelength range of 800 nm to 950 nm pass and light in a wavelength range blocked from 700 nm to 800 nm.