Light guide device and method for operating a light guide device

Abstract

The approach presented here creates a light-guiding device (117) with an objective (110) and a light-dividing element (115) which is arranged on an image side of the objective (120) and which is designed to split a light (132) radiating through the objective (120) onto the light-dividing element (115) into a first observation light (135), a second observation light (137) and a fluorescent light (140). The first observation light (135) represents a first partial image (147) of an object (120), and the second observation light (137) represents a second partial image (150) of the object (120), and the fluorescent light (140) represents a fluorescent image (152) of the object (120), wherein the fluorescent light (140) represents a light with a wavelength that can be emitted by fluorescent regions of the object (120).A stereoscopic light image of the object (120) can be formed by the first (147) and second partial image (150), the first partial image (147) being assigned to a first sub-aperture (Ap1) in a focal plane of the objective (110), the second partial image (150) being assigned to a second sub-aperture (Ap2) in a focal plane of the objective (110) which differs from the first sub-aperture (Ap1), the fluorescence image (140) being assigned to a third sub-aperture (Ap3) which has a larger area than the sum of the first (Ap1) and second (Ap2) sub-apertures, and the fluorescence light (140) being guided in a fluorescence light beam path (157) which is parallel to an optical axis (160) of the objective (110) and / or an optical beam axis of the first (135) and / or second (137) observation light.

Description

[0001] The present invention relates to a light-guiding device and a method for operating such a light-guiding device according to the main claims.

[0002] In endoscopy and laparoscopy, various imaging techniques are combined to provide a surgeon with more information than just a two-dimensional image of the object. Stereo endoscopes can be used here, which detect a left and a right color image via two separate optical channels, enabling a 3-dimensional display of the object. An advantageous technical implementation uses a common front optics for the left and right images and creates the different viewing angles through laterally offset sub-apertures in the pupil of this front optics. The light beams from the two sub-apertures are each imaged onto a sensor, thus creating a left and a right image of the object. This design is very typical for stereo microscopes, which use a single microscope objective as standard, as disclosed, for example, in DE 10 2018 110 643 B3.Such systems also exist in endoscopy and laparoscopy, with the advantage that this design allows for smaller mechanical diameters of the camera system while maintaining the same light conductance, as additional space between the left and right channels in the front optics is avoided. However, most of these systems do not include a fluorescence channel.

[0003] The key quality criterion for fluorescence imaging is a high signal-to-noise ratio. The higher the optical fiber's light conductance, the greater the proportion of the sample's fluorescence signal that can be detected by the optics, and the lower the concentrations of fluorescent substances (such as markers or tissue) that can be identified. A three-dimensional representation, or a particularly sharp image of the fluorescence signal, which is usually diffuse in practice, is of secondary importance. Methods are also known with which a two-dimensional fluorescence image can be computer-superimposed onto a three-dimensional representation, for example from US 11 690 500 B2. An increase in the light conductance, and thus the diameter of the optics, is limited by the cost of the optics and, above all, by the restrictions of the mechanical outer diameter of endoscopes and laparoscopes, which are typically less than 10 mm, and often well under 5 mm.

[0004] EP 2 505 989 A1 describes a stereoendoscope in which the left and right channels are split and used for fluorescence imaging. The problem of low signal strength is not addressed.

[0005] US Patent No. 11,690,500 B2 describes a stereoendoscope in which the left and right channels are split and used for chemical analysis. It also describes methods for superimposing the two-dimensional information on the three-dimensional white-light image. The problem of low signal strength is not addressed.

[0006] The publication DE 10 2018 110 643 B3 describes a stereo microscope with multiple beam splitters to provide additional views or additional image information. The problem of low signal strength is not addressed.

[0007] The publication DE 10 2015 216 570 A1 describes a microscopy system with white light and fluorescence imaging, in which the pupil of the fluorescence beam path is larger than that of the white light system. Stereo imaging is achieved using a switchable pupil. However, the problem of installation space is much less critical in microscopy and is not addressed by the described solution. Furthermore, switching elements can be susceptible to failure.

[0008] WO 2007 / 085496 A1 discloses a microscopy system for sequentially observing various fluorescent dyes accumulated in a tissue. For this purpose, an illumination system of the microscopy system has several different operating states, wherein in one operating state, the illumination radiation has a spectrum that encompasses an excitation band of only a first of several fluorescent dyes. An observation system also has several different corresponding operating states. Rotating filter carriers are provided for switching between the operating states. A disadvantage is that the operating states are switched one after the other, which leads to a latency period and can also cause artifacts. Furthermore, wear of the mechanical parts is to be feared.

[0009] DE 10 2010 033 825 A1 discloses a fluorescence observation system with a filter set. The filter set comprises an illumination light filter and an observation light filter. The filters exhibit several partial characteristics, i.e., different transmission values ​​in separate wavelength bands.

[0010] DE 10 2008 062 650 A1 discloses a surgical microscope for observing infrared fluorescence and a normal light image. It comprises microscope optics for optically imaging an object area onto a camera system to generate images, a display system for presenting the images to a user, and an illumination system for providing light onto the object area. The camera system has a dichroic beam splitter and three camera chips. Red light is primarily fed to a first camera chip, green light to a second camera chip, and blue light to a third camera chip. The beam splitter is configured so that infrared light is fed to only one of the three camera chips. Disadvantages are the complex structure and the large space requirement for the microscope system, as well as the low light intensity of the fluorescence channel compared to the white light channel.

[0011] DE 10 2020 101 879 A1 discloses a stereo microscope and a microscopy method for generating a stereo image of an object. Disadvantages include the complex design and the large amount of space required.

[0012] DE 10 2018 110 640 A1 discloses a method and a microscope for imaging an object. The microscope operates in a first operating mode and a second operating mode, wherein in the first operating mode, the object is stereoscopically imaged onto a stereo camera. Furthermore, a second image signal, which may be a fluorescence signal, is superimposed on a display device. A disadvantage is the low light intensity of the fluorescence channel compared to the white light channel.

[0013] DE 10 2018 110 641 B3 discloses a microscopy method for imaging an object and a microscope. A region of interest is defined in the electronic image and a depth of field is set within this region of interest.

[0014] DE 10 2018 110 642 A1 discloses a microscopy method for imaging an object and a microscope. The method simultaneously records the user's viewing direction and determines a depth distribution to shift the viewed image content to a central area of ​​a display unit. Disadvantages include the complex structure and the large space requirements of the microscope system, as well as the low light intensity of the fluorescence channel compared to the white light channel.

[0015] DE 10 2006 006 014 A1 discloses a microscopy system for observing fluorescence. The invention relates to a microscopy system for observing the fluorescence of a fluorescent dye in an object region. Furthermore, an illumination light in the visible wavelength range is provided. Rotating filter carriers are provided for switching. A disadvantage is that this introduces a latency period and can also cause artifacts.

[0016] From DE 10 2018 106 651 A1 a visualization system and a method for generating holographic representations from optical signals are known.

[0017] DE 10 2023 101 104 A1 discloses a visualization system for microsurgery, which comprises an imaging device, an illumination device, and a polarization determination system. A fluorescence channel may also be provided. Disadvantages include the large space required and the low light intensity of the fluorescence channel compared to the white light channel.

[0018] DE 10 2023 123 537 B3 discloses an optical observation system and a method for capturing fluorescence images. The optical observation system comprises a stereomicroscope with a fluorescence channel, which includes a detachable fluorescence camera attached to a mechanical interface.

[0019] DE 24 23 136 A1 discloses a device for automatically focusing stereomicroscopes using a servo motor for the focus drive. The servo is controlled by a phase-sensitive differential signal obtained from the signals of two photoreceivers by illuminating the specimen with pulsed light.

[0020] DE 10 2020 100 677 B3 discloses an optical observation instrument that can be used as an exoscope or surgical microscope. It comprises an optical unit with a lens arrangement and at least one electronic image sensor. The optical unit has a first stereo channel with a first beam path and a second stereo channel with a second beam path for recording a stereo image of an object area. A bracket for an operating device is provided.

[0021] Surgical visualization systems and display devices are known from US 2023 / 0255446 A1. These systems use movable arms to position components such as the display and microscope.

[0022] US 2022 / 0054223 A1 discloses medical devices that provide visualization of a surgical procedure. A remote control unit is used that can be used for multiple imaging systems.

[0023] US 2018 / 0368656 A1 discloses surgical visualization systems that can provide visualization of a surgical procedure. The system includes a control system for moving a movable arm to adjust the position of the camera in response to user input.

[0024] US 2017 / 0143442 A1 discloses medical devices that provide visualization of a surgical procedure. The medical device includes an electronic switching system for video signals.

[0025] Another surgical imaging system is known from US 2017 / 0020627 A1. This system comprises several imaging modules connected to each other via interfaces. Data flows are described for selecting suitable cameras from a multitude of cameras.

[0026] Against this background, the present invention seeks to provide a possibility for an improved light-guiding device and an improved method for operating such a light-guiding device. A high fluorescence signal combined with a small installation space is desirable, particularly for endoscopy applications.

[0027] This problem is solved by the subject matter of the main claims.

[0028] The approach proposed here creates a light-guiding device with the following features: - a lens; and - a light-dividing element arranged on an image side of the objective and configured to divide light radiating through the objective onto the light-dividing element into a first observation light, a second observation light, and a fluorescent light. The first observation light represents a first partial image of an object that is or can be arranged on an object side of the objective, and the second observation light represents a second partial image of the object, and the fluorescent light represents a fluorescent image of the object. The fluorescent light represents light with at least one wavelength that can be emitted by fluorescent regions of the object. A stereoscopic light image of the object can be formed by the first and second partial images, the first partial image being assigned to a first sub-aperture in a focal plane of the objective.the second partial image is assigned to a second sub-aperture in a focal plane of the objective that differs from the first sub-aperture, the fluorescence image is assigned to a third sub-aperture that has a larger area than the sum of the first area of ​​the first sub-aperture and the second area of ​​the second sub-aperture, and wherein the fluorescent light is guided in a fluorescent light beam path that is parallel to an optical axis of the objective and / or an optical beam axis of the first and / or second observation light.

[0029] The subapertures can be configured to overlap. In particular, the first subaperture can overlap the third subaperture, and the second subaperture can also overlap the third subaperture. In particular, the first and second subapertures can be configured as partial areas of the third subaperture.

[0030] Advantageously, the second subaperture may be formed so as not to overlap with the first subaperture.

[0031] The fluorescent light can have one or more wavelengths or wavelength ranges. Each of the wavelength ranges can be represented by a central wavelength of that wavelength range. The wavelength ranges of the fluorescence can be narrowband. The fluorescent light can have multiple wavelengths, especially if multiple fluorophores are excited in the specimen.

[0032] In this case, an objective can be understood as an optical element which is designed, for example, in the form of a lens, in particular a converging lens, in order to generate an image of an object located on one object side on an image side. The image side can be the side opposite the object side with respect to the objective. The objective can also comprise several lenses. The objective can have a fixed focal length. This can make it cost-effective. However, it can also be designed as a zoom lens and have a variable focal length. In this case, the magnification scale of the images can be adjustable. A light splitting element can be understood as an element which is designed to split a light beam into several different partial light beams. The individual partial light beams can take different paths from one another.In particular, a first partial light beam can be understood as a first observation light in a first observation light channel, and a second partial light beam can be understood as a second observation light in a second observation light channel, wherein the first and second observation lights can display a stereoscopic image of the object, which, for example, a user of the light-guiding device can view. Viewing can take place, for example, on a monitor or using VR (virtual reality) glasses if the image is captured with cameras. The images can also be transmitted directly to the doctor's brain via a computer-brain interface, as known, for example, from WO 2021 / 011401 A1 or WO 2023 / 038829 A1, as soon as this technology with the necessary functionality becomes available.Fluorescent light can be understood as light that has a specific wavelength corresponding to a wavelength emitted by one or more areas of an object when these areas are excited with an excitation light. The fluorescence wavelength can usually be longer than the excitation wavelength. The excitation light can be a light that also serves to illuminate the object for the purpose of recording the stereo image. However, a special excitation light can also be used, such as ultraviolet light. The special excitation light can be combined with the illumination light and shined onto the object.

[0033] The light splitter can have a long-pass characteristic, a band-pass characteristic, or a multi-band-pass characteristic. The latter can be understood as a filter with multiple pass ranges. Pass ranges can be understood as wavelength ranges with high transmission of the light splitter, ideally 100%, in the real case, for example, over 90%. In the wavelength ranges that are not pass ranges, the light splitter can have high reflectivity, ideally 100%, in the real case, for example, over 90%, and consequently low transmission. For example, the light splitter can be designed such that the light with this specific or expected fluorescence wavelength is coupled out and coupled into the fluorescence light beam path.This fluorescent light beam path is arranged or aligned such that it is parallel to an optical axis of the objective and / or an optical beam axis of the first and / or second observation light, so that the fluorescent light and the first observation light and / or the second observation light essentially run parallel and next to one another or can be guided in corresponding light guides. Particularly advantageously, the fluorescent light can run or be guided in the optical axis. In particular, a central ray of the fluorescent light can run in a straight line in the optical axis of the objective. The beam path of the fluorescent light can therefore be free of beam deflections. The central ray of the fluorescent light can run in a straight line over its entire path between the objective and the image sensor.The beam paths of the first and second observation light, however, can advantageously each have at least one beam deflection, for example by means of mirror elements and / or beam splitters. The image of the object recorded with at least one image sensor thus represents an image of the object in a specific wavelength range, in particular a white light image or a monochromatic image. To record the light image, the image sensor can record light reflected or scattered by the object and / or light transmitted through the object. For this purpose, light can be provided for illumination. This can be incident light illumination and / or transmitted light illumination. The light image can be recorded free of fluorescent light from the object. The light image can be a stereoscopic image which, as explained above, comprises at least two partial images.The two partial images can be captured with a separate image sensor, or both partial images can be captured with the same image sensor, for example, at different locations on the image sensor. The two partial images can represent different viewing angles at which the object is imaged.

[0034] Such an embodiment of the approach proposed here advantageously enables a compact design of a light-guiding device, so that, despite minimal installation space requirements, a user of this light-guiding device still has the option of receiving a stereoscopic image of the object and simultaneously evaluating the corresponding fluorescent light, which can be fed to a corresponding display or evaluation unit via a separate channel. Furthermore, by appropriately sizing the aperture (third aperture) for the fluorescent light, it can be ensured that the fluorescent light, which is often characterized by very weak or low intensity, is still available with a sufficient amount of light and can thus be optimally evaluated.

[0035] An embodiment of the approach presented here is advantageous in which the light splitter element comprises at least one beam splitter and / or one dielectric mirror and / or one prism and / or one prism arrangement and / or one beam splitter plate. Furthermore, the light splitter element can comprise a short pass and / or a long pass and / or a band pass and / or a multi-band pass and / or a notch filter and / or a multi-notch filter. Such an embodiment of the approach presented here offers the advantage of using a mature or widely available component for the light splitter element, enabling the light-guiding device to be manufactured cost-effectively.

[0036] A particularly advantageous embodiment of the approach proposed here is one in which the light-dividing element comprises at least one dielectric mirror arranged on a beam splitter plate or a beam splitter cube. Such an embodiment offers the advantage of a very compact yet optically highly functional shape for the light-dividing element.

[0037] For a high degree of integration capability of the individual components of the light-guiding device, an embodiment in which the light-dividing element is designed to form the third sub-aperture in a ring-shaped and / or circular shape is advantageous. Such an embodiment offers the possibility of designing the third sub-aperture with the largest possible area while still being able to integrate it, for example, into a housing with a small installation space requirement.

[0038] Particularly advantageous with regard to the evaluation of the fluorescent light is an embodiment with a modification mask element for modifying the phase and / or amplitude of the fluorescent light. Such an embodiment offers the advantage of being able to efficiently prepare the fluorescent light with respect to the parameters to be examined, thus simplifying the corresponding evaluation of this fluorescent light.

[0039] An embodiment of the approach presented here can be designed very compactly if the light-guiding element is configured to guide the fluorescent light in a region between or to the side of the first observation light and the second observation light. This allows, for example, the space available in a tube or endoscope to be used very efficiently to guide the individual partial light beams. This allows the invention to be used for an endoscope, but also for an exoscope, a visualization system for open surgery with minimal access, in which the camera is arranged outside of a patient or animal to be treated.

[0040] A particularly advantageous embodiment of the approach proposed here is one in which the lens and the light-guiding element are embedded in a common tube-like element, in particular in an endoscope, in particular wherein the tube-like element has a maximum diameter of 20 millimeters, in particular a maximum of 10 millimeters, in particular a maximum of 5 millimeters. Small diameters can be particularly advantageous for endoscopes. Such an embodiment offers the advantage of splitting the different light beams very efficiently and together for a user in a common sheath. This allows the invention to be used advantageously and profitably, for example, in the medical and veterinary fields. A tube-like element can be understood as a flexible body which, when stretched, has a hollow cylindrical shape.The length of this body can be at least ten times its diameter. A larger diameter, for example, between 10 mm and 100 mm, may be considered, especially for exoscopes.

[0041] Furthermore, an embodiment of the approach proposed here as an image recording device with a variant of a light guide device presented here, an illumination unit for illuminating the object with an illumination light and a sensor unit for capturing the first and second partial images and the fluorescence image is favorable, in particular wherein the illumination unit is designed to output the illumination light with a predetermined wavelength in order to cause an expected fluorescence in at least one region of the object and to obtain the first and second observation light in an optically visible spectrum.Such an embodiment of the approach proposed here offers the advantage that by using the lighting unit as well as the sensor unit, a fully functional assembly can be provided, which is, for example, completely enclosed in a common casing and can thus be designed very compactly.

[0042] The object can be viewed particularly well by a user of a variant of the image recording device presented here if the illumination unit is configured to emit the illumination light at least partially onto the object in a central beam along the optical axis or at least partially in a central beam that has an angle of incidence on the object that is inclined relative to the optical axis. This allows for the implementation of illumination of the object that enables a highly three-dimensional, perspective, and detailed image of the object.

[0043] Another conceivable embodiment of the approach proposed here is one in which the illumination unit is configured to emit the illumination light in a plurality of separate partial beams, the partial central beams of which are arranged at different azimuth angles with an angle of incidence inclined to the optical axis of the lens. For example, a conical oblique illumination of the object can be achieved, with an angle of incidence that can be the same. Such an embodiment offers the advantage of being able to illuminate certain areas of the object from different directions, for example, so that the risk of shadows being cast on the object can be avoided or at least reduced.

[0044] An embodiment of the approach proposed here is advantageous as a method for operating a variant of an image recording device presented here, the method comprising the following steps: - Illuminating the object with the illuminating light by the lighting unit; and - Capturing the first and second partial images and the fluorescence image with the sensor unit.

[0045] The advantages mentioned above can also be realized quickly and efficiently by means of such an embodiment in the form of a method.

[0046] Furthermore, the method may comprise calculating the stereoscopic image from the two partial images.

[0047] Furthermore, the method may include superimposing the acquired stereoscopic image with the acquired fluorescence image using an image processing unit. For example, fluorescent image areas may be highlighted in the image display.

[0048] The approach presented here further provides a control unit configured to perform, control, or implement the steps of a variant of a method presented here in corresponding devices. This embodiment of the invention in the form of a control unit also allows the problem underlying the invention to be solved quickly and efficiently.

[0049] For this purpose, the control unit can have at least one computing unit for processing signals or data, at least one memory unit for storing signals or data, at least one interface to a sensor or an actuator for reading sensor signals from the sensor or for outputting control signals to the actuator, and / or at least one communication interface for reading or outputting data embedded in a communication protocol. The computing unit can be, for example, a signal processor, a microcontroller, or the like, wherein the memory unit can be a flash memory or a magnetic storage unit.The communication interface can be designed to read in or output data wirelessly and / or via a wired connection, wherein a communication interface that can read in or output wired data can read this data, for example, electrically or optically from a corresponding data transmission line or output it to a corresponding data transmission line.

[0050] In this case, a control unit can be understood as an electrical device that processes sensor signals and outputs control and / or data signals depending on them. The control unit can have an interface that can be implemented in hardware and / or software. In a hardware implementation, the interfaces can, for example, be part of a so-called system ASIC, which contains a wide variety of functions of the control unit. However, it is also possible for the interfaces to be separate integrated circuits or to consist at least partially of discrete components. In a software implementation, the interfaces can be software modules that are present, for example, on a microcontroller alongside other software modules.

[0051] Also advantageous is a computer program product or computer program with program code that can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out, implement and / or control the steps of the method according to one of the embodiments described above, in particular when the program product or program is executed on a computer or a device.

[0052] An embodiment may be particularly advantageous in which the object is illuminated with excitation radiation to excite fluorescence radiation from the object and / or the object is illuminated with an illuminating light, in particular a white light, to capture the light image. The excitation radiation and / or the illuminating light may also have a central beam arranged parallel to the optical axis of the front lens, or the excitation radiation and / or the illuminating light may have a central beam arranged at an angle of incidence inclined to the optical axis of the front lens (which corresponds to oblique illumination).The excitation radiation and / or the illumination light can also comprise several separate partial beam bundles, whose central rays are arranged at different azimuth angles with an angle of incidence inclined to the optical axis of the front objective (which corresponds to conical oblique illumination), whereby the angle of incidence can be the same. The excitation radiation and / or the illumination light can also be arranged as episcopic illumination and / or the excitation radiation and / or the illumination light can be arranged as diascopic illumination. It is also conceivable that, according to a further embodiment, the splitting of the observation light passed through the front objective is accomplished with at least one of the following elements: beam splitter, dielectric mirror (short pass, long pass, band pass, multiband pass, notch filter, multi-notch filter), prism, prism arrangements.Alternatively or additionally, the observation light transmitted through the front lens can be split using at least one dielectric mirror arranged on a beam splitter plate or a beam splitter cube. The third subaperture can also be annular.

[0053] An embodiment is also conceivable in which the phase of the observation light in the fluorescence channel is further modified by means of a phase mask.

[0054] Instead of a prism, a beam splitter plate can also be used, which has a minimal impact on the image quality in the fluorescence image. For example, the third subaperture can also have a region outside the projected beam splitter in a z-projection of the beam splitter onto the pupil plane. In other words, a portion of the observation light in the fluorescence channel can be guided past the beam splitter. This allows the beam splitter to be made small, thus saving material and weight.

[0055] The approach presented here advantageously enables a method for simultaneously recording a fluorescence image and a stereoscopic light image of an object, wherein the stereoscopic light image comprises a first partial image and a second partial image. First, an observation light emanating from the object is passed through a front lens with an image-side focal plane, after which the observation light passed through the front lens is split into a fluorescence channel, a first observation channel, and a second observation channel. Subsequently, the fluorescence image is recorded using a fluorescence image sensor in the fluorescence channel, and the first partial image is recorded using a first image sensor in the first observation channel. The second partial image is also recorded using a second image sensor in the second observation channel.Here, the first partial image (for example, the left stereo image) is assigned to a first subaperture in the focal plane of the front objective, and the second partial image (for example, the right stereo image) is assigned to a second subaperture in the focal plane of the front objective, which is different from the first subaperture. The fluorescence image is assigned to a third subaperture in the focal plane of the front objective, which is larger than the sum of the first and second subapertures. The fluorescence channel between the front objective and the fluorescence image sensor can also have a fluorescence beam path whose optical axis is parallel to the optical axis of the front objective over its entire length. An embodiment constructed in this way can advantageously create a light-guiding device that is very compact and requires little installation space. The course of the optical axis of the fluorescence beam path can be defined by its central ray.

[0056] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows: Fig. 1 schematic representation of an embodiment of an image recording device; Fig. 2 shows a further embodiment of an image recording device; Fig. 3 a schematic representation of a further embodiment of the image recording device presented here Fig. 4 a schematic representation of a further embodiment of the image recording device presented here; Fig. 5 a schematic representation of a further embodiment of an image recording device; Fig. 6 a schematic arrangement of the different subapertures; Fig. 7 is a flowchart of a method according to an embodiment; and Fig. 8 a block diagram of a control unit according to an embodiment.

[0057] In the following description of advantageous embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, whereby a repeated description of these elements is omitted.

[0058] Fig. 1 shows a schematic representation of an embodiment of an image recording device 100. The left part of the image shows an xz view, with the optical axis 160 running in the z direction and the x, y, and z directions forming a Cartesian coordinate system. The image recording device 100 comprises a housing or casing 105, which is configured, for example, in a tubular shape. Provided in this casing 105 are, for example, an objective lens 110 and a light-dividing element 115 as a light-guiding device 117.If the object 120 is now illuminated with an illumination light 125 from an illumination unit 130, the light 132 reflected by the object 120 is projected through the lens 110 onto the light dividing element 115 arranged on the image side of the lens 110, wherein the reflected light 132 is split by this light dividing element 115 into a first observation light 135, a second observation light 137 and a fluorescent light 140. For this purpose, appropriate prisms 142 or dichroic mirrors 145 can be provided, for example, in the light dividing element 115. In this way, it can be achieved that, using appropriate optical components 146, such as those shown in FIG. Fig. 1, the first observation light 135 images a first partial image 147, the second observation light 137 images a second partial image 150, and the fluorescent light 140 images a fluorescent image 152, which can be imaged on different partial areas of a sensor unit 155. The first partial image 147 and the second partial image 150 can be used to create a stereo image of the object 120, which can be displayed, for example, to a user of the image recording device, such as a doctor, when the image recording device 100 is used as an endoscope to examine a patient. At the same time, it can be seen that the fluorescent light 140 is output in a fluorescent light beam path 157, which is aligned parallel to an optical axis 160 of the objective 110 such that, in this case, it coincides with this optical axis 160. The central beam of the fluorescent light 140 runs straight along the optical axis 160 of the objective.The beam path of the fluorescent light 140 is therefore free of beam deflections. The beam paths of the first and second observation lights (135, 137), however, each have two beam deflections.

[0059] The image recording device 100 can advantageously be used in such a way that the fluorescent light 140 can now be coupled out into a different beam path than the first observation light 135 and the second observation light 137. This can be achieved by the light dividing element 115 coupling out a specific wavelength or a specific wavelength range as fluorescent light 140 in the fluorescent light beam path 157, whereas a wavelength range of the remaining spectrum is coupled out into different optical paths as first observation light 135 and second observation light 137. In this case, a region of the fluorescent light 140 can furthermore have a larger aperture than the sum of the apertures of the first observation light 135 and the second observation light 137 in a pupil plane P1. This representation of the apertures in an xy plane, namely the pupil plane P1, is shown on the right side of the Fig. 1. This shows the circular or annular cross-section of the first subaperture Ap1 (first illumination light 135), the second subaperture Ap2 (second illumination light 137), and the third subaperture Ap3 (fluorescence light 140). The significantly larger third subaperture is clearly visible, which now allows for better collection and subsequent evaluation of weak light signals from the reflected light 132 in the spectrum of the fluorescent light 140, whereas this is usually not necessary for the first observation light 135 and the second observation light 137.

[0060] Fig. 2 shows a further embodiment of an image recording device 100. In contrast to the Fig. 1, for example, the dichroic mirrors 145 of the light dividing element 115 do not extend over the entire surface of a prism 142. In a modification of the example, the mirrors 145 are not dichroic, but rather broadband or wavelength-independent reflecting, for example, such that all the light in this area, i.e., all wavelengths, are reflected into the first observation light 135 or the second observation light 137, so that no more light reaches the corresponding areas in the area of ​​the third sub-aperture Ap3. Although this results in a weakening of the light intensity in the fluorescent light 140, this is usually not significant if the areas of the dichroic mirrors 145, and thus the intensities lost from the fluorescent light 140, are small or negligible compared to the other areas of the third sub-aperture Ap3.

[0061] Fig. 3 shows a schematic representation of a further embodiment of the image recording device 100 presented here. Compared to the representation from the Fig. 1, it can now be seen that the object 120 can be illuminated not only by the illumination unit 130 with the illumination light 125, but that external illumination in the form of transmission illumination with a corresponding transmission illumination light 300 can also be provided. It is further conceivable that the fluorescent light 140 can be guided through a corresponding phase plate 310 and / or a fluorescent light filter 320 in order to change corresponding parameters of the fluorescent light 140, for example, to improve the evaluation of this fluorescent light 140. Fig. 3 furthermore, that the sensor unit has individual sensors 330 or sections of a sensitive area of ​​the sensor unit 155, in which the first observation light 135, the second observation light 137 or the fluorescent light 140 can be received, respectively.

[0062] Fig. 4 shows a schematic representation of another embodiment of the image recording device 100 presented here in a yz representation. In contrast to the Fig. 3, the first observation light 135 and the second observation light 137 are now offset in the same direction y relative to the fluorescent light 140, so that the illumination light 135 shown in the right-hand illustration Fig. 4 results in the arrangement of the corresponding subapertures Ap1, Ap2, and Ap3. The subapertures are shown in an xy plane perpendicular to the optical axis. For example, a correspondingly restricted area of ​​the third subaperture Ap3 can be realized by a mirror 145 corresponding to the restricted area, which is provided to transmit the fluorescent light 140. For example, the light splitter element 115 can be restricted to a portion of the fluorescent light 140 that is necessary for coupling out the first observation light 135 and the second observation light 137. One possible embodiment is a beam splitter plate.

[0063] Fig. 5 shows a schematic representation of a further embodiment of an image recording device 100. In contrast to the Fig. 1 and Fig. 2, the image recording device 100 is designed such that the fluorescent light 140 in the fluorescent light beam path 157 is split into two partial beams or into two parts of the sub-aperture Ap3, which are guided laterally between the first observation light 135 and the second observation light 137. The representation of the corresponding sub-apertures Ap1, Ap2 and Ap3 is shown in the right-hand illustration of the Fig. 5 in a top view. The subelements 115 here comprise a corresponding filter 500 to filter out a corresponding wavelength of the fluorescent light 157 and direct it to a corresponding area of ​​the sensor unit 155. This filter 500 can also be configured to change an amplitude or phase of this fluorescent light, for example, to better evaluate the properties of this fluorescent light.

[0064] Fig. Figure 6 shows a schematic arrangement of the different subapertures Ap1, Ap2 and Ap3. In the right part of the Fig. 6 is in contrast to the arrangement of the corresponding subapertures Ap1, Ap2 and Ap3 in Fig. 5 the area of ​​the aperture Ap3 is enlarged compared to the area of ​​the subapertures Ap1 and Ap2. The left partial view from Fig. Figure 6, however, shows another possible arrangement of the corresponding subapertures Ap1, Ap2, and Ap3, whereby the third subaperture Ap3 is no longer divided, but is arranged laterally to the left of the first subaperture Ap1 and the second subaperture Ap2. In order to be able to record the corresponding signals in the subapertures Ap1, Ap2, and Ap3, corresponding sensor areas or sensors 330 should also be provided in the sensor unit 155 at the respective positions of the subapertures Ap1, Ap2, and Ap3.

[0065] The basic idea for solving this problem is to utilize the entire / larger pupil AP3 for fluorescence imaging and the smaller partial pupils AP1 and AP2 for stereo imaging, while maintaining a compact design. This increases the light conductance for fluorescence imaging, allowing more signal to be captured. This principle can be implemented differently depending on the system.

[0066] In a first variant, as for example in the Fig. 1 and Fig. As shown in Figure 2, the light for the stereo imaging is separated from the light for the fluorescence imaging after the common front optics before, after, or advantageously near the pupil plane P1 of the system (gray beam path). This can be achieved, for example, by a beam splitter, dielectric mirror, splitter cube, prisms, prism arrays, or similar optics for beam splitting. A pupil AP3 is used for the fluorescence imaging that is larger than the sum of the two sub-apertures AP1 and AP2 of the stereo imaging. The advantage is the smaller overall diameter of the optics with a simultaneously higher light conductance for the fluorescence imaging. The geometric arrangement of the sub-apertures AP1 and AP2 of the stereo imaging can advantageously be designed to minimize the geometric outer diameter.In this application, a common zoom and / or focus can be advantageously realized (lens elements for zoom / focusing can be moved collinearly for all three channels).

[0067] In addition, beam splitting is also possible without spectral splitter effect purely spatially, e.g. with reflective subapertures AP1 and AP2, as shown in the Fig. 2 is shown.

[0068] Beam splitting into different sub-apertures for stereo imaging and fluorescence imaging may also be possible, as shown in the Fig. 3, wherein each subaperture is assigned an imaging optic 146 and a sensor 330. Here, a division into four individual channels can be made according to the common pupil plane P1, with two of the channels being used for stereo imaging and two for fluorescence imaging. The subapertures for fluorescence imaging can be arranged symmetrically or asymmetrically to the optical axis 160, as can be seen from Fig. 6. At the same time, they do not necessarily have to be circular. One advantage is that the minimized outer diameter of the entire optics or image acquisition device can be kept very small. The disadvantages of this implementation are the higher cost of imaging optics at the pupil plane and the smaller available pupil for fluorescence imaging.

[0069] Since a larger pupil reduces the depth of field of the optics, it may be advantageous to use one of the following methods to increase the depth of field for the fluorescence channel: - Ring pupil: The depth of field increases when the fluorescence pupil is formed as a ring pupil. At the same time, however, the signal intensity is reduced. - Phase mask: By using a specially shaped phase and / or amplitude mask in the pupil of the fluorescence image, e.g. a Toraldo phase mask, a multifocal lens, a diffractive element, the depth of field can be extended at the expense of resolution and transmission. - Phase mask + image processing: Using a specially shaped phase and / or amplitude mask in the pupil of the fluorescence image, e.g., a cubic phase mask, the system's point response can be optimized to remain as constant as possible over a large defocus range. Any associated deterioration in resolution is compensated for by subsequent digital deconvolution of the image.

[0070] A corresponding imaging system with illumination (in transmission or reflected light) and three sensors for recording a fluorescence image, a left and right stereo image is in the Fig. 3. Also shown is a possible position of the phase plate 310 to increase the depth of field of the fluorescence image, together with a fluorescence filter 320, which usually limits the spectrum of the transmitted light to the emission range of the fluorophore.

[0071] Fig. 7 shows a flowchart of an embodiment of a method 700 for operating a variant of an image recording device, wherein the method 700 comprises a step 710 of illuminating the object with the illumination light by the illumination unit and a step 720 of capturing the first and second partial images and the fluorescence image with the sensor unit.

[0072] Fig. 8 shows a block diagram of an embodiment of a control unit 800 for executing a variant of the method 700 for operating a variant of an image recording device, wherein the control unit 800 has a unit 810 for illuminating the object with the illumination light by the illumination unit and a unit 820 for capturing the first and second partial images and the fluorescence image with the sensor unit.

Claims

[1] Light-guiding device (117) having the following features: - a lens (110); and - a light dividing element (115) arranged on an image side of the objective (110) and designed to divide a light (132) radiating through the objective (110) onto the light dividing element (115) into a first observation light (135), a second observation light (137) and a fluorescent light (140), wherein the first observation light (135) represents a first partial image (147) of an object (120) that can be arranged or is arranged on an object side of the objective (110), and the second observation light (137) represents a second partial image (150) of the object (120), and the fluorescent light (140) represents a fluorescent image (152) of the object (120), wherein the fluorescent light (140) represents light with at least one wavelength that is emitted by fluorescent regions of the object (120) can be emitted, wherein a stereoscopic light image of the object (120) can be formed by the first (147) and second partial image (150),the first partial image (147) is assigned to a first subaperture (Ap1) in a focal plane of the objective (110), the second partial image (150) is assigned to a second subaperture (Ap2) in a focal plane of the objective (110) that differs from the first subaperture (Ap1), the fluorescence image (140) is assigned to a third subaperture (Ap3) that has a larger area than the sum of the first area of the first subaperture (Ap1) and the second area of the second subaperture (Ap2), and wherein the fluorescent light (140) is guided in a fluorescent light beam path (157) that is parallel to an optical axis (160) of the objective (110) and / or an optical beam axis of the first (135) and / or second (137) observation light. [2] Light guide device (117) according to claim 1, wherein the light splitting element (115) comprises at least one beam splitter and / or a dielectric mirror and / or a prism and / or a prism arrangement and / or a beam splitter plate. [3] Light guide device (117) according to one of the preceding claims, wherein the light splitting element (115) comprises at least one dielectric mirror arranged on a beam splitter plate or a beam splitter cube. [4] Light guide device (117) according to one of the preceding claims, wherein the light dividing element (115) has a long-pass characteristic or a band-pass characteristic or a multi-band-pass characteristic. [5] Light guide device (117) according to one of the preceding claims, in which the light dividing element (115) is designed to make the third sub-aperture (Ap3) annular and / or circular. [6] Light guide device (117) according to one of the preceding claims, with a modification mask element (310) for modifying a phase and / or an amplitude of the fluorescent light (140). [7] Light guide device (117) according to one of the preceding claims, in which the light dividing element (115) is designed to guide the fluorescent light (140) in a region between or to the side of the first observation light (135) and the second observation light (137). [8] Light-guiding device (117) according to one of the preceding claims, in which the objective (110) and the light-dividing element (115) are embedded in a common tube-like element (105), in particular in an endoscope, in particular wherein the tube-like element (105) has a diameter of at most 10 millimeters, in particular at most 5 millimeters. [9] Image recording device (100) with a light guide device (117) according to one of claims 1 to 8, an illumination unit (130) for illuminating the object (120) with an illumination light (125) and a sensor unit (155) for detecting the first (147) and second (150) partial images and the fluorescence image (152), in particular wherein the illumination unit (130) is designed to output the illumination light (125) with a predetermined wavelength in order to cause an expected fluorescence in at least one region of the object (120) and to obtain the first (135) and second (137) observation light in an optically visible spectrum. [10] Image recording device (100) according to claim 9, wherein the illumination unit (130) is designed to output the illumination light (125) at least partially in a central beam in the optical axis (160) onto the object (120) or at least partially in a central beam having an angle of incidence on the object (120) that is inclined relative to the optical axis (160). [11] Image recording device (100) according to claim 9 or 10, wherein the illumination unit (130) is designed to output the illumination light (125) in a plurality of separate partial beams, the partial central beams of which are arranged at different azimuth angles with an angle of incidence inclined to the optical axis (160) of the objective (110). [12] Method (700) for operating an image recording device (100) according to one of claims 9 to 11, wherein the method (700) comprises the following steps: - illuminating (710) the object with the illuminating light by the illuminating unit; and - capturing (720) the first and second partial images and the fluorescence image with the sensor unit. [13] Control device (800) which is configured to execute and / or control the steps (710, 720) of the method (700) according to claim 12 in corresponding units (810, 820). [14] Computer program configured to execute and / or control the steps of the method (700) according to claim 12.

Images