Filter changing device for an endoscopic camera, camera head for an endoscope and retrofit kit for retrofitting a camera head and / or an endoscope

Abstract

The invention relates to a filter changing device for an endoscopic camera, wherein the filter changing device has at least a first rotatable filter wheel, a second rotatable filter wheel and a rotatable first connecting wheel, wherein the first filter wheel and the second filter wheel each have at least two receptacles for one optical filter each, the filter wheels have a common first axis of rotation, the second filter wheel has a first engagement plane with teeth distributed completely over its outer circumference and the first connecting wheel is designed as a gear with teeth distributed completely over its outer circumference, wherein the first filter wheel has a partial section with distributed teeth along its outer circumference and the first connecting wheel is arranged on the outer circumference of the first filter wheel and on the outer circumference of the second filter wheel in such a way,that the teeth of the partial section of the first filter wheel engage with the teeth of the first connecting wheel for rotating the first connecting wheel, and the teeth of the first connecting wheel engage with the teeth of the first engagement plane of the second filter wheel, so that when the first filter wheel is driven by the drive unit, at least one receptacle of the first filter wheel and the second filter wheel can be positioned parallel in the optical passage. Furthermore, the invention relates to a camera head for an endoscope and a retrofit kit for retrofitting a camera head and / or an endoscope.

Description

[0001] The invention relates to a filter changing device for an endoscopic camera, wherein the filter changing device comprises a base plate, an optical passage with an optical axis, at least one first rotatable filter wheel, a second rotatable filter wheel, and a rotatable first connecting wheel, as well as a drive unit for driving one of the filter wheels, wherein the first filter wheel and the second filter wheel each have at least two receptacles for an optical filter, the filter wheels have a common first axis of rotation, the second filter wheel has a first engagement plane with teeth distributed completely around its outer circumference, and the first connecting wheel is designed as a gear with teeth distributed completely around its outer circumference. The invention further relates to a camera head for an endoscope and a retrofit kit for retrofitting a camera head and / or an endoscope.

[0002] In medical and non-medical applications, observation instruments such as endoscopes are used to examine internal cavities of a human or animal body, or of an industrial or technical object, such as a pipeline. For imaging, a camera head with an image sensor can be used in conjunction with the endoscope. To improve image quality and / or enable different observation modes, it is known to incorporate various filters into the optical path of the observation instrument.

[0003] For example, in fluorescence imaging, the object under investigation is exposed to light with excitation radiation. This excites a fluorophore, previously applied to the object or already present, to emit light of a specific emission wavelength. The excitation wavelength and the emission wavelength are usually different; typically, the emission wavelength is longer than the excitation wavelength. The emitted light is usually significantly weaker than other light sources, such as the excitation fluorescence light or the imaging white light. For these reasons, it is necessary to filter out unwanted wavelength bands so that, ideally, only the desired spectrum and / or the emission wavelength of the fluorophore reaches the camera head in fluorescence mode.Besides switching between different observation modes, where usually two or more filters are inserted sequentially into the optical path of the observation system, it can also be advantageous to insert two different filters into the optical path simultaneously. Various filter changers are known for this purpose.

[0004] DE 10 2020 100 676 B3 discloses a filter changing device for an optical observation instrument with two beam paths, which has three filter wheels arranged one behind the other along a common axis and rotatable about this common axis and relative to each other, wherein each filter wheel has at least one filter and at least one free optical passage, such that a filter or a free optical passage of each filter wheel can be inserted into each of the two beam paths. The second filter wheel is driveable, and the first filter wheel is coupled to the second filter wheel via a first drive gear, and the third filter wheel is coupled to the second filter wheel via a second drive gear. A disadvantage of this is that, due to the central second driven filter wheel and the connection of the first and third filter wheels arranged on both sides via a drive gear, the number of filter wheels that can be arranged one behind the other in series is limited to three.

[0005] Furthermore, a mechanical binary counter by the "Institute for Free Art Machines / Felix Scharstein" (www.scharstein.de / #binaerzaehler) is known as an art object. This binary counter is based on a purely binary mechanism in which exactly two positions are provided for each revolution of a gear driven by a shaft. The number panels of the mechanical binary counter are arranged along a rotational axis with gears positioned between them. These gears partially engage with a second row of gears arranged behind them on a second rotational axis. The opposing surfaces of the panels are arranged along the rotational axis and thus occupy a considerable amount of space in its longitudinal direction. Moreover, this mechanical binary counter requires a large number of individual parts, which makes the mechanism prone to malfunction.

[0006] The purpose of the invention is to improve the state of the art.

[0007] The problem is solved by a filter changing device for an endoscopic camera, wherein the filter changing device comprises a base plate, an optical passage with an optical axis, at least one first rotatable filter wheel, a second rotatable filter wheel and a rotatable first connecting wheel, as well as a drive unit for driving one of the filter wheels, wherein the first filter wheel and the second filter wheel each have at least two receptacles for an optical filter, the filter wheels have a common first axis of rotation, the second filter wheel has a first engagement plane with teeth distributed completely over its outer circumference, and the first connecting wheel is designed as a gear with teeth distributed completely over its outer circumference.wherein the first filter wheel has a section with distributed teeth along its outer circumference and the first connecting wheel is arranged on the outer circumference of the first filter wheel and on the outer circumference of the second filter wheel such that the teeth of the section of the first filter wheel can engage with the teeth of the first connecting wheel to rotate the first connecting wheel and the teeth of the first connecting wheel can engage with the teeth of the first engagement plane of the second filter wheel, so that when the first filter wheel is driven by means of the drive unit, at least one receptacle of the first filter wheel and of the second filter wheel can be positioned parallel in the optical passage.

[0008] Thus, a filter changing device is provided with which two or more filters can be precisely and efficiently swung in and out of the beam path of an endoscopic camera and / or endoscope simultaneously. It is particularly advantageous that only a single drive unit is required, and that this single drive unit acts on only one filter wheel, setting this filter wheel into rotation. Through the coupling of the driven filter wheel to the adjacent filter wheel via the connecting wheel, the adjacent filter wheel itself is also set into rotation as long as the corresponding teeth are engaged.Because the at least two filter wheels are arranged in a row along the common axis of rotation, with their respective opposing wheel surfaces perpendicular to the axis, the filter wheels can be rotated fully or partially clockwise and counterclockwise as desired. This allows for the combination of optical filters that can be swung in parallel for each shot. Most importantly, the simple clockwise and / or counterclockwise rotation enables any sequence and rapid switching between different filters and / or filter combinations, thus allowing for quick succession of different observation modes and imaging techniques.

[0009] By arranging the filter wheels in a row along the axis of rotation, with their surfaces positioned perpendicular to the axis, a compact filter changing device is achieved. This compact size allows for easy integration into a camera head or use as a compact connector between a camera head and an endoscope. The dimensions of the filter changing device are minimized not only longitudinally by arranging the filter wheels with their thinner material along the axis of rotation, but also transversely. While the filter wheels must have a sufficient diameter for the desired number of optical filter images, each connecting wheel serves only to transfer the rotational movement of the preceding filter wheel to the next.This allows the diameter of each connecting wheel to be significantly smaller than the diameter of the respective filter wheels, thus minimizing the overall diameter of the filter changing device.

[0010] Because the first filter wheel and / or a terminal filter wheel has a section with distributed teeth along its outer circumference, when this filter wheel is driven, the teeth of this section engage with the teeth of the first connecting wheel, causing the connecting wheel to rotate. The teeth of the first connecting wheel, in turn, engage with the teeth of the first engagement plane of the second filter wheel, which has teeth distributed evenly around its outer circumference. Thus, a full rotation of the first filter wheel results in half a rotation of the second filter wheel due to the section with teeth on the first connecting wheel. This mechanical, originally binary mechanism allows various combinations of optical filters to be simultaneously pivoted and arranged in the beam path using only a single drive unit.Each gear can be fitted with an optical filter, meaning that at least two optical filters can be fitted and positioned simultaneously and in parallel in the beam path.

[0011] A key aspect of the invention is that, in a series of filter wheels, only the first and / or terminal filter wheel is driven. Due to a toothed section that does not extend the full circumference of the first filter wheel, the rotational movement is only transmitted to the subsequent second filter wheel via the connecting wheel when the circumferential teeth of a connecting wheel engage this section. This causes the second filter wheel to rotate, allowing a corresponding filter holder of the second filter wheel to pivot parallel into the beam path. If the circumferential section is free of the first toothed section and is aligned with the teeth of the first connecting wheel, no engagement occurs between the first filter wheel and the first connecting wheel, and consequently, the first connecting wheel and the second filter wheel remain stationary.Thus, a mechanical binary transmission mechanism is implemented in which, when the first and / or preceding filter wheel rotates, the second and / or subsequent filter wheel either remains stationary or rotates itself. This ensures that at least one of the two filter wheels is positioned within the beam path, and therefore at least two filters are simultaneously swung into the beam path. Consequently, a filter device is provided with which at least two identical and / or different filters, particularly fluorescence filters, can be precisely, quickly, efficiently, and, most importantly, simultaneously and with a long service life, swung into and out of the beam path of an endoscopic camera due to the purely mechanical transmission mechanism. In addition to the rapid filter change, the frequency of use of a specific filter can also be predetermined by inserting identical and / or different filters into the images.For example, an observation mode using normal white light is typically used more frequently than fluorescent light. Therefore, it is advantageous to place a white light filter before and / or after a fluorescent filter in successive shots of a filter wheel, or offset between shots of two or more filter wheels. This allows not only the desired more frequent use of white light by switching to a white light filter, but also provides the user with a clear visual indication of the change between two identical or different consecutive filters, such as two fluorescent filters. This reduces the risk of unintentionally working in the wrong observation mode. The following terms will be explained:

[0012] A "filter changing device" is, in particular, a device with which at least two filters can be moved in or out of the optical beam path in parallel and simultaneously, and / or arranged in the optical passage. The filter changing device can be activated manually or automatically by means of a drive unit for the parallel changing of at least two filters by rotating the first and / or a terminal filter wheel. Thus, one or more filters can be automatically or manually pivoted into and out of the optical passage by rotation. The filter changing device has at least a first filter wheel and a second filter wheel, as well as at least a first connecting wheel, wherein the first connecting wheel, with its circumferential teeth, can engage both the teeth of the section of the first filter wheel and the teeth of the first engagement plane of the second filter wheel.Accordingly, the connecting wheel is preferably arranged on the outer circumferences of the first and second filter wheels. The compact filter changing device can be integrated into a camera or, as a separate device, for example, designed as a snap-on filter, connectable to the camera and / or an endoscope. For automatic filter changing, the filter changing device can have a control element, such as a switch on its outer surface. Alternatively or additionally to optical detection of the filter change by the user, the filter changing device can also have a display element and / or a sensor, such as a Hall sensor.

[0013] A "base plate" is, in particular, a component of the filter changing device on which at least one axis of rotation is arranged internally. A base plate can also be a housing part and / or a housing cover of the filter changing device.

[0014] A "filter wheel" (also called a "changeable disc") is, in particular, a disc that has at least two receptacles, each for an optical filter. The filter wheel can, in particular, be designed as a gear. The receptacles are, in particular, arranged evenly spaced relative to each other along an inner circumference of the filter wheel and / or distributed across the wheel surface of the filter wheel. The respective filter wheel is, in particular, rotatable about the axis of rotation. The first filter wheel and / or one of the two end filter wheels can, in particular, be driven and rotated manually and / or by means of a drive unit and / or a motor. For this purpose, for example, the outer circumferential surface can be driven as a contact surface by means of a drive unit and / or a gearbox acting on this contact surface.For example, the drive engages an additional layer of the first filter wheel and / or the terminal filter wheel, which has fully circumferential teeth in addition to the first section in another layer. Preferably, however, the first filter wheel and / or the terminal filter wheel is connected to a rotating shaft and is driven by rotating the shaft using a drive unit or manually. The respective filter wheel is, in particular, a flat, planar component, the opposing wheel surfaces of which are oriented essentially perpendicular to the optical axis and / or the axis of rotation. Thus, at least two filter wheels or several filter wheels are aligned with their opposing wheel surfaces to each other and, in particular, transversely to the axis of rotation. This results in the filter wheels, with their respective material thicknesses, being arranged in a row along the axis of rotation.The filter wheel is designed in particular as a round wheel and / or disc. Preferably, the filter wheel has a circular cross-section. However, the filter wheel can also have an elliptical cross-sectional shape and thus be designed as an elliptical wheel.

[0015] The filter wheel can have teeth and / or a gear ring distributed around its entire circumference, or it can have teeth distributed only over a section of its circumference. The uniformly distributed teeth of a filter wheel can be homogeneous and continuous along the entire thickness of the filter wheel, and thus along the optical axis and / or axis of rotation, or the teeth can be arranged in a plane, meaning they do not extend across the entire thickness of the wheel. Therefore, a filter wheel can have teeth uniformly distributed over its entire circumference and thickness. Likewise, a filter wheel can have teeth uniformly distributed over a section of its outer diameter and across its entire thickness.A filter wheel can also have teeth uniformly distributed along its entire outer diameter in a first engagement plane and a section with uniformly distributed teeth on its end face and / or outer surface in a second engagement plane following the axis of rotation and / or optical axis. The teeth of the first engagement plane and the second engagement plane, including the section, are particularly similar and / or continuous along the material thickness. The section of the outer surface of the respective gear and / or the respective engagement plane that is free of teeth has a smaller diameter in this tooth-free area than a section and / or an engagement plane with distributed teeth. Thus, the tooth-free section along the outer circumference can be designed as a recess and / or a relief.Thus, each filter wheel can be designed with a first engagement plane as a complete gear and a second engagement plane as a partial gear.

[0016] The filter wheels each have a bore, in particular, partially or completely through their material thickness, for the insertion and / or passage of the first axis of rotation. The bore is, in particular, located centrally to the diameter of the respective filter wheel. The first axis of rotation for the filter wheels is, in particular, located inside the housing of the filter changing device, attached to its base plate and / or a housing cover. Since the optical passage through the housing of the filter changing device is preferably located centrally to the outer diameter of the housing, the first axis of rotation of the filter wheels and / or the second axis of rotation of the connecting wheel or wheels is arranged correspondingly further outwards and off-center.The first filter wheel and / or a terminal filter wheel may in particular have a shaft for driving, wherein the shaft is arranged on the side of the wheel surface which is oriented opposite to the side towards the second filter wheel.

[0017] By forming the first filter wheel with a section of distributed teeth, and by engaging these teeth with the teeth of the first connecting wheel, only a partial rotation is transmitted to the second filter wheel, which is also engaged with the first connecting wheel, via the first connecting wheel during a complete rotation of the first filter wheel. Thus, the first filter wheel and / or a terminal filter wheel only partially transmits power to the first connecting wheel and the coupled second filter wheel. The maximum rotation distance for a full rotation of the filter wheel to achieve a desired filter combination is (2 n) / 2 with n = number of filter wheels.

[0018] A "connecting gear" (also "auxiliary gear") is, in particular, a gear. The connecting gear has teeth that are evenly distributed around its circumference and / or across its material thickness. The connecting gear is, in particular, designed as a spur gear and / or cylindrical gear. The axis of rotation of the connecting gear is, in particular, parallel to the axis of rotation of the filter wheels. The respective connecting gear and the two filter wheels into which this connecting gear engages, in particular, form a spur gear drive. A connecting gear has, in particular, a significantly smaller diameter than the diameter of a filter holder. Two or more connecting gears can be arranged on a common axis of rotation. For this purpose, the respective connecting gear has, in particular, a central through-bore for the passage of the axis of rotation.The axis of rotation can be attached inside the housing of the filter changing device, for example on a base plate or a housing cover.

[0019] The "first axis of rotation" is designed as a common axis for the rotatable filter wheels, and the "second axis of rotation" as a common axis for the connecting wheels. A "common axis of rotation" is understood to be, in particular, a machine element for supporting the rotatable filter wheels or connecting wheels. The common axis of rotation does not itself rotate and therefore does not transmit any torque. The stationary common axis of rotation thus also forms a common axis of rotation for the filter wheels or connecting wheels. The common axis of rotation also ensures, in particular, that the filter wheels or connecting wheels are arranged in a continuous line along this axis.For this purpose, each filter wheel preferably has a central bore, so that the common axis of rotation is guided through the central bores of the filter wheels and thus the filter wheels are "aligned" in a straight line with their center point.

[0020] In principle, it should be emphasized that the terms "first" and "second" filter wheel or "first" and "second" subsection, filter and other terms only serve to differentiate and do not necessarily specify an order.

[0021] A "receptacle" (also called a "filter receptacle") is, in particular, a cavity and / or a hollow body that can be inserted into an opening within the respective filter wheel. The receptacle can, in particular, have a partial or complete outer enclosure and / or rim into which an optical filter can be inserted, and which at least partially encloses the optical filter around its circumference. A receptacle can, for example, be a short, tubular body. The receptacle primarily serves as a protective cover for the optical filter. However, the receptacle can also be a direct opening, for example, a bore, through the material thickness of the respective filter wheel. Optionally, the respective filter wheel can also have a filter receptacle that does not contain an optical filter and thus allows unobstructed passage through the optical beam path.Thus, an empty filter holder can also be inserted into the optical path and the beam path using the respective filter wheel. Likewise, instead of omitting an optical filter, a free passage can also be achieved by a non-filtering optical element, such as a glass pane. A glass pane used as a window can also have an anti-reflective coating.

[0022] An "optical filter" (also simply called a "filter") is, in particular, an optical element that selects and thus transmits or blocks incident radiation and / or rays based on specific properties such as wavelength, polarization state, angle of incidence, and / or direction of incidence. An optical filter can also modify the properties of the transmitted light, for example, by converting circularly polarized light into linearly polarized light. Specifically, an optical filter can block a specific spectral wavelength band. Examples of optical filters include graduated filters, edge filters, polarizing filters, and interference filters. An interference filter, in particular, has a coating that blocks or transmits light within a specific spectral range.The optical filter can be used in particular as an observation filter and / or detection filter, a fluorescence observation filter, or an excitation filter. The optical filter is made of glass or a crystalline material. The optical filter can be planar or designed as a filter lens. In principle, instead of the optical filter, another optical element, such as a lens, an aperture, a polarizer, or a similar optical element, can also be arranged in the filter changing device and / or the filter holder.

[0023] The term "white light filter" refers specifically to a situation where a particular image and / or position is free of an optical element, or where an optical element in a particular image and / or position is free of any filtering function, so that the light and / or white light, in particular, is transmitted unchanged. White light is transmitted by a white light filter without altering its light properties, especially its wavelengths. A white light filter can also be a filter that blocks near-infrared light. A "white light filter" can also be a filter that filters the light to improve image quality when illuminated with white light. For this purpose, a BG39 filter from Schott, for example, can be used.Thus, a white light filter can also be used to adapt the light captured by an image sensor and / or a camera to a sensitivity curve and / or a specific sensitivity of the human eye.

[0024] A "fluorescence observation filter" (also called a "fluorescence filter") is, in particular, an optical polychromatic interference filter for separating the emitted fluorescence light from the input excitation light. Thus, the fluorescence filter blocks the specific fluorescence excitation radiation and allows the fluorescence emission radiation to pass along the optical path. Preferably, the fluorescence filter completely blocks the excitation light while allowing the fluorescence emission light to pass through, which typically has a longer wavelength than the excitation light. Therefore, a fluorescence filter is, in particular, an observation filter that filters out the excitation light that causes a fluorophore to fluoresce. This is advantageous because the excitation light is usually several orders of magnitude brighter than the resulting and / or emitted fluorescence light, which would otherwise be overpowered.A fluorescent filter can also be a "blue filter", "red filter", "IR filter" or "NIR filter".

[0025] A "blue filter" is understood to be a filter that filters out the blue excitation light from a light source but allows the fluorescence light, especially fluorescence emitted by a fluorophore, to pass through, at least predominantly. For example, when using the fluorophore FITC (fluorescein isothiocyanate, a green derivative of fluorescein), excitation is achieved with an LED at a wavelength of 460 nm, whereby longer-wavelength fluorescence light with a maximum at approximately 520 nm in the green spectral range is emitted by the fluorophore. In order to clearly visualize the emitted fluorescence light of FITC in imaging, the blue excitation light is filtered out using the filter changer and / or camera.

[0026] The term "red filter" refers in particular to a filter which filters out the red excitation light of a light source, but allows the fluorescence light, especially fluorescence light emitted by a fluorophore, to pass through, at least predominantly.

[0027] The term "IR filter" refers in particular to a filter which filters out infrared excitation light from a light source, but allows the fluorescence light, especially fluorescence light emitted by a fluorophore, to pass through, at least predominantly.

[0028] The term "NIR filter" refers in particular to a filter which filters out near-infrared excitation light from a light source, but allows the fluorescence light, especially fluorescence light emitted by a fluorophore, to pass through, at least predominantly.

[0029] An "optical passage" is, in particular, a recessed space in the filter changing device through which light can pass. An optical passage is, in particular, a continuous opening through the filter changing device, its other components, and / or a housing of the filter changing device. The optical passage is, in particular, arranged around the center point of the cross-section of the rotatable filter wheels and / or around the optical axis. The optical passage extends, in particular, along the optical axis. In the direction of light propagation, a filter holder and / or an optical filter may, in particular, be arranged in front of and / or within the optical passage. Likewise, the optical passage may be free of an arranged optical filter and / or a holder when light passes through it. In principle, the optical passage can have any cross-sectional shape; preferably, the optical passage is circular in cross-section.

[0030] An "optical axis" is, in particular, a line along which a degree of rotational symmetry exists in an optical system. The optical axis is, in particular, an imaginary line that defines a path along which light propagates through the filter-changing device and / or the camera toward an image sensor. Preferably, the optical axis runs through the curvature of the filter being swung into place and / or a downstream lens system and / or objective system. However, the optical axis can also be bent and / or directed by a lens, an optical element, and / or one of the optical filters. The optical beam path, as the geometric progression of light rays, is, in particular, arranged in and / or around the optical axis and runs along, converging and / or dispersing with respect to, the optical axis.

[0031] A "camera" (also called a "camera head") is, in particular, a device for receiving image light along an optical axis from an endoscope and for focusing the received image light onto at least one image sensor. In addition to the at least one image sensor, the camera may, in particular, have an aperture or window for transmitting the received image light and a lens system for focusing the image light onto the at least one image sensor. The image data captured by at least one image sensor can, in particular, be transmitted electronically from the camera head to a display system and / or to an image processing unit in order to display the endoscopic image for the user. The camera may include means for detecting the connected endoscope and for processing algorithms. A connector for connecting an endoscope to the camera may be arranged at the distal end of the endoscope and / or the proximal end of the camera head.The filter changing device according to the invention can also itself be designed as a connector for connecting an endoscope to a camera. To avoid vignetting and thus shadowing at the image edge, the filter changing device is preferably integrated into the camera module.

[0032] An "endoscope" is a medical or industrial device used for the endoscopic examination and viewing of a human or animal body cavity and / or an industrial cavity, such as a pipe. The endoscope typically includes a handpiece, a shaft, a light source, a fiber optic cable, a sensor, and / or a camera. A video endoscope, in particular, features digital image acquisition and transmission, and thus an integrated or connectable camera. Besides applications in human and veterinary medicine, an endoscope and / or video endoscope can also be used for industrial purposes, such as visual inspection in hard-to-reach cavities. In industrial applications, an endoscope is often referred to as a borescope.

[0033] An "image sensor" is, in particular, a light-sensitive electronic component that relies on an internal photoelectric effect. The image sensor records one or more images from the viewing area of ​​the imaging device and converts them into electronic signals. The image sensor has a sensor plane in the image plane of the optical system, a lens system, and / or the objective lens. An electronic image sensor can be, in particular, a CCD sensor (charge-coupled device) or a CMOS sensor (complementary metal oxide-semiconductor).

[0034] In a further embodiment, the filter changing device has a second connecting wheel, a third connecting wheel and / or optionally further connecting wheels and a third filter wheel, a fourth filter wheel and / or optionally further filter wheels, wherein the third filter wheel, the fourth filter wheel and / or optionally the further filter wheels each have at least one first engagement plane with teeth distributed completely evenly over the respective outer circumference.

[0035] Thus, the number of successive filter wheels along the first axis of rotation can be scaled as desired, and the filter changing device can be extended. Any number of intermediate wheels can therefore be arranged between the driven first and / or terminal filter wheel and an opposing second terminal wheel. These intermediate wheels have, in particular, at least one first engagement plane with teeth distributed uniformly over their respective outer circumference, into which the teeth of the connecting wheel engage, which also engages the teeth of the previous filter wheel. To move from an existing filter position to a new filter position when using the filter changing device, a maximum of (2 n) / 2 revolutions of the first driven and / or the terminal filter wheel are necessary. The first driven and / or terminal filter wheel can be rotated clockwise or counterclockwise. It is particularly advantageous that, despite an arbitrarily large number of filter wheels, the arrangement of the filter wheels with their material thicknesses along the first axis of rotation requires minimal installation space along the axis of rotation and / or the optical axis.

[0036] A third, fourth, and optionally a further filter wheel are essentially filter wheels as defined above. However, these third, fourth, and optionally further filter wheels are specifically arranged as intermediate wheels with a different arrangement of teeth evenly distributed along the outer circumference. These third, fourth, and optionally further filter wheels, as intermediate wheels, particularly feature a first engagement plane with teeth evenly distributed completely around their respective outer circumferences. Preferably, all teeth of the filter wheels and / or connecting wheels have the same tooth geometry to ensure optimal transmission of motion to the next connecting wheel and / or filter wheel.In principle, however, it should be noted that the respective teeth of the filter wheels and / or the connecting wheels can also have different geometries, for example tooth flanks or points of engagement, as long as a connecting wheel can engage with the respective associated teeth of the filter wheels.

[0037] The terminal filter wheel, which is arranged opposite the first and / or terminally driven filter wheel and encloses the intermediate intermediate wheels, can, instead of having at least one first engagement plane with teeth distributed uniformly over the respective outer circumference, also have teeth which extend over the entire material thickness of this terminal filter wheel.

[0038] A second, third, and optionally further connecting wheel are essentially connecting wheels as defined above. Preferably, all connecting wheels are geometrically identical. However, the geometric shape of the connecting wheels may differ slightly from one another, as long as each connecting wheel fulfills its function of transmitting the rotational movement of the preceding filter wheel to the following filter wheel.

[0039] In order to continue the binary mechanical transmission mechanism to the respective subsequent filter wheel, the second filter wheel, the third filter wheel, the fourth filter wheel and / or optionally the further filter wheels can each have a second engagement plane with a section with distributed teeth along the respective outer circumference.

[0040] In a further embodiment of the filter changing device, the section of the first filter wheel and / or the section of the respective second engagement plane of the second filter wheel, the third filter wheel, the fourth filter wheel and / or optionally of each further filter wheel has teeth in a range of 45% to 55%, in particular 48% to 52%, preferably 50% of the respective outer circumference.

[0041] Thus, with a full rotation of the preceding filter wheel, approximately or exactly half a rotation is transferred to the following filter wheel by means of the associated connecting wheel, since the toothless section of the first filter wheel and / or the respective engagement plane of a filter wheel rotates past the associated connecting wheel without engagement and without contact.

[0042] To provide redundant filter combinations and thus enable quick switching between different combinations, the respective filter wheel can have four, six and / or optionally additional even-numbered recordings for each optical filter.

[0043] By increasing the number of slots for optical filters on each filter wheel, certain filter combinations are available multiple times during filter changes and rotation, enabling faster switching and changes between different filter combinations. In principle, starting with two filter slots per filter wheel, the number of slots can be varied as desired. However, an even number of slots is required, otherwise, due to the mechanics, a filter on a subsequent filter wheel could be obscured by the preceding one. More than two filter slots on a single filter wheel are achieved by ensuring that each subsequent filter wheel only rotates after a half turn (180°) of the preceding wheel.

[0044] In another embodiment of the filter changing device, the drive unit has a single motor for driving the first filter wheel or a terminal filter wheel of the filter changing device.

[0045] Due to the mechanical, binary translation and transmission of the movement of the first filter wheel or a terminal filter wheel, designed as described above for the first filter wheel, only a single motor is required to drive all filter wheels via the connecting gears. This increases the service life of the filter changing device and reduces wear and installation space, as each filter wheel does not need to be driven by its own motor. Because of the mechanical, binary transmission between the filter wheels, desired filter combinations can be achieved in parallel in the beam path with just one motor and can even be provided redundantly. The motor can drive a shaft connected to the first and / or terminal filter wheel.

[0046] In order to implement a drive via the outer circumference of the first and / or terminal filter wheel, the first filter wheel or the terminal filter wheel can have a drive section with teeth distributed completely over the respective outer circumference, so that the first filter wheel or the terminal filter wheel can be driven via a drive gear by means of a single motor.

[0047] In another embodiment of the filter changing device, the first filter wheel or the terminal filter wheel has a shaft or a receptacle for a shaft along the first axis of rotation for connection to the single motor.

[0048] To keep the number of components of the filter changing device low, the connecting wheels can have a common second axis of rotation.

[0049] In another embodiment of the filter changing device, the first axis of rotation and / or the second axis of rotation is or are arranged on the base plate.

[0050] In order to provide an exact holding mechanism during the period in which the respective filter wheel is not engaging with a connecting wheel with its teeth, the filter changing device can have a holding device to hold a non-rotating filter wheel in its position during driving.

[0051] A "holding device" can be, in particular, a device and / or component that ensures that a non-rotating filter wheel or several filter wheels are held in their respective rest positions. The holding device can be implemented, for example, by means of magnetic force, a spring, friction, and / or another mechanism.

[0052] Thus, while a toothless section of a particular filter wheel rotates past the associated connecting wheel without engagement, rotation of the subsequent filter wheel can be prevented by mechanically holding it in position by a retaining device, for example, a spring-loaded pressure piece. Furthermore, a spacer or other design feature can prevent direct, frictional contact between the wheel surfaces of successive filter wheels.

[0053] In another aspect of the invention, the problem is solved by a camera head for an endoscope, wherein the camera head has an image sensor, an opening for receiving light of an image along an optical path and an optical lens system for focusing the light onto the image sensor, wherein the camera head has at least one previously described filter changing device.

[0054] This provides a camera head with a compact, space-saving filter exchange device integrated into or attached to it. If at least one filter exchange device is integrated directly into the camera head, the camera head can be detachably connected to various types of endoscopes. Naturally, the camera head can also feature two or more filter exchange devices arranged in series along an optical path and / or the optical axis. However, a single filter exchange device, due to the parallel arrangement of any number of filter wheels and thus filters, already enables a wide range of filter combinations, various possible filter settings, and applications. Therefore, the camera head facilitates diverse multispectral imaging and / or the broad application of various fluorophores in fluorescence imaging.

[0055] To adapt a currently used filter configuration or to adapt it for different desired observation modes, the camera head can include a detection unit for identifying the respective optical filter in the optical path. Likewise, the camera head can include a control unit for adjusting the rotation speed of the filter plate and for checking and / or adjusting the respective optical filter positioned in the beam path according to the selected operating mode.

[0056] In a further aspect of the invention, the problem is solved by a retrofit kit for retrofitting a camera head and / or an endoscope, wherein the retrofit kit has at least one previously described filter changing device, so that the filter changing device can be arranged between a proximal end of the endoscope and a distal end of the camera head.

[0057] Thus, a retrofit kit (also referred to as an "adapter") is provided with at least one filter changing device, which simultaneously serves as a connector between an existing endoscope and an existing camera head, as well as enabling different observation modes. Additionally, the retrofit kit can also include two or more filter changing devices arranged in series between the endoscope and the camera head, or one filter changing device can be replaced by another filter changing device according to the invention to enable different applications and / or observation options.

[0058] The invention will now be explained in more detail using exemplary embodiments. These will show... Fig. 1 A schematic three-dimensional section view of an endoscope system with an endoscope, a filter changer and a camera head, Fig.2. A three-dimensional representation of a filter changer in side view with an endoscope image and a camera image. Fig. 3 a three-dimensional representation of the open filter changer from Fig. 2 with an interior view, Fig. 4 a three-dimensional representation of a first filter gear, Fig. 5 a three-dimensional representation of a second filter gear, Fig. 6 a three-dimensional representation of a third filter gear, Fig. 7 a three-dimensional representation of a connecting gear, and Fig. 8 A three-dimensional representation of the filter changer with the housing open, showing the filter gears and the connecting gears.

[0059] An endoscope system 171 comprises a camera head 177, a filter changer 101, and an endoscope 173. The filter changer 101 is connected to the camera head 177 by means of a camera mount 179 and to the endoscope 173 by means of an endoscope mount 175. Fig. 1 and Fig. 2) Furthermore, the filter changer 101 has a housing 103 with a base plate 107 designed as a distal cover. The base plate 107 is externally connected to a proximal cover of the housing 103 by means of screws 105.

[0060] Inside the housing 103, the filter changer 101 has a first filter gear 121, a second filter gear 123, and a third filter gear 125, the third filter gear 125 being located above the base plate 107. Furthermore, the filter changer 101 has a first connecting gear 127 and a second connecting gear 129 ( Fig.8) An optical passage 113 with an optical axis 115 is formed through the base plate 107. The optical passage 113 and the optical axis 115 are arranged centrally and aligned with an outer diameter of the base plate 107 and the housing 103. Inside the housing 103, the base plate 107 has a connected first axis of rotation 117 and a second axis of rotation 119 ( Fig. 3).

[0061] The first filter gear 121 has a first filter holder 151, a second filter holder 152, a third filter holder 153, and a fourth filter holder 154, which are spaced apart from a central shaft 141 and the outer diameter of the first filter gear. Different optical filters (not shown) are inserted into each of these four filter holders 151, 152, 153, and 154. On its outer surface, the first filter gear 121 has a section 131 with teeth 133, which occupies 50% of the outer circumference of the first filter gear 121 and thus describes a circular arc of 180°. The other 50% of the outer circumference of the first filter gear 121 is formed as a recess 135 free of teeth. The shaft 141 has a recess on its underside, and thus opposite the one shown in the diagram. Fig. 4 shows a bore for receiving the first axis of rotation 117 on the upper wheel surface.

[0062] The second filter gear 123 also has four filter receptacles 151, 152, 153, and 154. A through bore 143 for the first axis of rotation 117 is formed in the center of the second filter gear 123. On its outer circumference, the second filter gear 123 has a [missing information - likely a specific feature or feature] adjacent to the [missing information - likely a specific feature or feature]. Fig. The upper wheel surface shown in Figure 5 has a first engagement plane 137 with circumferential teeth 133. Below this first engagement plane 137, a second engagement plane 139 has a section with a recess 135 along 50% of the outer circumference of the second filter gear 123, with another half of the outer circumference being formed with continuous teeth 133 over the first engagement plane 137 and the second engagement plane 139.

[0063] The third filter gear 125 also has four filter receptacles 151, 152, 153 and 154, as well as a central bore 143 for receiving the first axis of rotation 117. The third filter gear 125 has teeth 133 running continuously around its circumference and along its material thickness.

[0064] During a previous assembly of the filter changer 101, the third filter gear 125, with its bore 143, was placed on the first rotational shaft 117, so that the underside of the third filter gear 125 lies against the inner side of the base plate 107. Subsequently, the second filter gear 125 was installed as described in Fig.Figure 5, with its upper side facing upwards, is also placed with its bore 143 onto the first axis of rotation 117, so that the underside of the second filter gear 123 rests on the upper side of the third filter gear 125. Finally, the first filter gear 121, with its bore located inside the shaft 141, is placed onto the first axis of rotation 117, so that the underside of the first filter gear 121 rests on the upper side of the second filter gear 123. The first axis of rotation 117 is arranged such that each of the four filter holders 151, 152, 153, and 154 can be pivoted and positioned concentrically within the optical passage 113 and relative to the optical axis 115.

[0065] The first connecting gear 127 and the second connecting gear 129 are identical, each with a central bore 145 for the second axis of rotation 119 and with teeth extending through their outer diameters and height. The first connecting gear 127 is arranged on the second connecting gear 129 around the second axis of rotation 119 ( Fig. 7 and Fig.8) Here, the teeth 133 of the first connecting gear 127 mesh with the teeth 133 of the first filter gear 121 and the second filter gear 123, while the teeth 133 of the second connecting gear 129 mesh with the teeth 133 of the third filter gear 125. Thus, the first connecting gear 127 combines the section 131 with teeth 133 of the first filter gear 121 for motion transmission with the first engagement plane 137 with fully rotating teeth 133, and the second connecting gear 129 connects the second engagement plane 139 of the second filter gear 123 with the section with 50% of the rotating teeth 133 to the teeth 133 of the third filter gear 125.

[0066] The following work steps are carried out using the filter changer 101 and the endoscope system 171.

[0067] The shaft 141 is driven proximally by a single motor (not shown in the figures), thereby rotating the first filter gear 121 clockwise in the direction of rotation 111. As long as the teeth 133 of the first connecting gear 127 engage with the teeth 133 of the section 131 of the first filter gear 121, the first connecting gear 127 moves about the second axis of rotation 119. If the first connecting gear 127 simultaneously engages with the teeth 133 of the first engagement plane 137 and the fully circumferential teeth 133 of the second filter gear 123, then the second filter gear 123 is also rotated in the direction of rotation 111.Since all three filter gears 121, 123, and 125 are mounted only on the first axis of rotation 117, the transmission of motion from the first driven filter gear 121 to the second filter gear 123 and the subsequent third filter gear 125 occurs only via the two connecting gears 127 and 129. Accordingly, during a complete rotation of the first filter gear 121 in the direction of rotation 111, the second filter gear 123 is rotated by half a turn by means of the first connecting gear 127 due to the first section 131 with teeth 133, since the teeth 133 of the first connecting gear 127 do not engage in the area of ​​the recess 135 of the first filter gear 121 when the first connecting gear 127 is in position. Thus, the first connecting gear 127 is not rotated during half a revolution of the first filter gear 121.During a full rotation of the second filter gear 123, the third filter gear 125 is also rotated by half a rotation by means of the second connecting gear 129, as long as the teeth 133 of the second connecting gear 129 engage in the 50% rotating teeth 133 of the second engagement plane 139 of the second filter gear 123.

[0068] A quarter turn of the driven first filter gear 121 inserts the first filter holder 151, the second filter holder 152, the third filter holder 153, and the fourth filter holder 154 into the optical passage 113. Each of the four filter holders 151 to 154 of the first filter gear 121 contains a filter A, B, C, and D, respectively. These four filters A, B, C, and D are also inserted into the corresponding filter holders 151 to 154 of the second filter gear 123 and the third filter gear 125. This results in the filter combinations shown in Table 1. With a filter changer 101 described above, featuring the three filter gears 121, 123, and 125 and the four filter holders 151 to 154, all filter combinations shown in Table 1 are possible.If the three filter gears 121, 123 and 125 each have only two filter mounts, then only the filter position combinations marked with a preceding star are possible. Table 1: Combination possibilities for four filters A, B, C, D of the filter gears 121, 123, 125 Filter gear 125 Filter gear 123 Filter gear 121 Rotary angle filter gear 121 * A A A 0° A A B 90° * A A C 180° A B D 270° * A C A 360° A C B 450° * A C C 540° B D D 630° * C A A 720° C A B 810° * C A C 900° C B D 990° * C C A 1080° C C B 1170° * C C C 1260° D D D 1350°

[0069] In an alternative version of the filter changer 101, the filter changer 101 has only the first filter gear 121 and the third filter gear 125 as end filter gears, as well as a connecting first connecting gear 127. The four filter holders 151 to 154 of the first filter gear 121 and the third filter gear 125 are equipped with an exemplary selection of filters (Table 2). This alternative version of the filter changer 101 with only the first filter gear 121 and the third filter gear 125 is operated in principle as described above. Thus, the filter combinations shown in Table 3 can be set by rotating the first filter gear 121. Therefore, even with the alternative version of the filter changer 101 with only the two filter gears 121 and 125, all possible filter combinations are accessible and adjustable.As a comparison of the filter combinations in Table 3 with Table 1 shows, the filter changer described above with the three filter gears 121, 123 and 125 has the advantage that repeatable, redundant filter combinations are provided, thereby reducing the rotation length and thus the switching distance and the changeover time between particularly important and frequently used filter combinations. Table 2: Example of a possible filter selection for a filter changer with two filter gears Filter gear Filter A Filter B Filter C Filter D 125 No filter Red filter White filter NIR filter 121 White filter Blue filter No filter No filter Table 3: Combination possibilities with four filters A, B, C, D each, with two filter gears Filter gear 125 Filter gear 121 combination A A No filter, white filter A B No filter, blue filter A C No filter, no filter B D Red filter, No filter C A White filter, white filter C B White filter, blue filter C C White filter, No filter D D NIR filter, No filter

[0070] Thus, a filter changer 101 is provided, with which at least two different filters can be quickly, efficiently and precisely swung into the optical beam path in parallel using the filter gears 121, 123, 125 and which can be used with various types of endoscopes 173 and camera heads 177. Reference symbol list 101 filter changers 103 cases 107 Base plate 111 Direction of rotation 113 optical passage 115 optical axis 117 first axis of rotation 119 second axis of rotation 121 first filter gear 123 second filter gear 125 third filter gear 127 first connecting gear 129 second connecting gear 131 Section with teeth 133 teeth 135 recess 137 first intervention level 139 second intervention level 141 wave 143 Bore for first axis of rotation 145 Hole for the second axis of rotation 151 first filter recording 152 second filter recording 153 third filter intake 154 fourth filter recording 171 Endoscope system 173 Endoscope 175 Endoscope image 177 Camera head 179 camera shot QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 100 676 B3

[0004]

Claims

[1] Filter changing device (101) for an endoscopic camera, wherein the filter changing device (101) comprises a base plate (107), an optical passage (113) with an optical axis (115), at least one first rotatable filter wheel (121), a second rotatable filter wheel (123) and a rotatable first connecting wheel (127) as well as a drive unit for driving one of the filter wheels (121, 123), wherein the first filter wheel (121) and the second filter wheel (123) each have at least two receptacles (151, 152, 153, 154) for an optical filter, the filter wheels (121, 123) have a common first axis of rotation (117), the second filter wheel (121) has a first engagement plane (137) with teeth (133) distributed completely over its outer circumference, and the first connecting wheel (127) is a gear with teeth distributed completely over its outer circumference teeth (133) are formed, characterized by, that the first filter wheel (121) has a section (131) with distributed teeth (133) along its outer circumference, and the first connecting wheel (127) is arranged on the outer circumference of the first filter wheel (121) and on the outer circumference of the second filter wheel (123) such that the teeth (133) of the section (131) of the first filter wheel (121) can engage with the teeth (133) of the first connecting wheel (127) for rotating the first connecting wheel (127), and the teeth (133) of the first connecting wheel (127) can engage with the teeth (133) of the first engagement plane (137) of the second filter wheel (123), so that when the first filter wheel (121) is driven by means of the drive unit, at least one receptacle (151, 152, 153, 154) of the first filter wheel (121) and of the second filter wheel (123) is engaged. The filter wheel (123) can be positioned parallel to the optical passage (113). [2] Filter changing device (101) according to claim 1, characterized by, that the filter changing device (101) has a second connecting wheel (129), a third connecting wheel and / or optionally further connecting wheels and a third filter wheel (153), a fourth filter wheel and / or optionally further filter wheels, wherein the third filter wheel (153), the fourth filter wheel and / or optionally the further filter wheels each have at least one first engagement plane (137) with teeth (133) distributed completely evenly over the respective outer circumference. [3] Filter changing device (101) according to claim 1 or 2, characterized by that the second filter wheel (123), the third filter wheel (125), the fourth filter wheel and / or optionally the further filter wheels each have a second engagement plane (139) with a section (131) with distributed teeth (133) along the respective outer circumference. [4] Filter changing device (101) according to one of the preceding claims, characterized by, that the subsection (131) of the first filter wheel (121) and / or the subsection (131) of the respective second engagement plane (139) of the second filter wheel (123), the third filter wheel (125), the fourth filter wheel and / or optionally of each further filter wheel has teeth (133) in a range of 45% to 55%, in particular 48% to 52%, preferably 50% of the respective outer circumference. [5] Filter changing device (101) according to one of the preceding claims, characterized by , that each filter wheel (121, 123, 125) has four positions (151, 152, 153, 154), six positions and / or optionally further even-numbered positions for each optical filter. [6] Filter changing device (101) according to one of the preceding claims, characterized by , that the drive unit has a single motor for driving the first filter wheel (121) or a terminal filter wheel of the filter changing device. [7] Filter changing device (101) according to claim 6, characterized by , that the first filter wheel (121) or the terminal filter wheel has a drive section with teeth distributed completely over the respective outer circumference, so that the first filter wheel (121) or the terminal filter wheel can be driven by a drive gear using the single motor. [8] Filter changing device (101) according to claim 6, characterized by , that the first filter wheel (121) or the terminal filter wheel has a shaft (141) or a receptacle for a shaft along the first axis of rotation (117) for connecting to the single motor. [9] Filter changing device (101) according to any one of claims 2 to 8, characterized by , that the connecting wheels (127, 129) have a common second axis of rotation (119). [10] Filter changing device (101) according to any of the preceding claims, characterized bythat the first axis of rotation (117) and / or the second axis of rotation (119) is or are arranged on the base plate (107). [11] Filter changing device (101) according to one of the preceding claims, characterized by , that the filter changing device (101) has a holding device for holding a non-rotating filter wheel (125) in its position when driven. [12] Camera head (177) for an endoscope (173), wherein the camera head (177) comprises an image sensor, an aperture for receiving light of an image along an optical path and an optical lens system for focusing the light onto the image sensor, characterized by that the camera head (177) has at least one filter changing device (101) according to one of claims 1 to 11. [13] Retrofit kit for retrofitting a camera head and / or an endoscope, characterized by, that the retrofit kit has at least one filter changing device (101) according to one of claims 1 to 11, such that the filter changing device (101) can be arranged between a proximal end of the endoscope (173) and a distal end of the camera head (177).

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