Endoscope device, correction pair assembly, endoscope, and imaging system

Abstract

The invention relates to an endoscopic device (110) comprising a lens assembly (112) configured for imaging light in the visible and near infrared ranges, and the lens assembly is symmetrical about a first plane of symmetry (120) perpendicular to an optical axis (114). The lens assembly (112) includes six rod lenses (122) and two correction elements (124), each including a lens system (128) having a first lens (130) and a second lens (132). The first lens (130) is made of a first lens and the second lens (132) is made of a second lens. The first lens and the second lens have different Abbe numbers, wherein opposing partial dispersion of the first lens and the second lens deviates from the lens with normal dispersion in an opposite manner. The lens assembly (112) further comprises a correction pair assembly (134) comprising two of the correction elements (124) that are symmetrical to each other about a second plane of symmetry (136) perpendicular to the optical axis (114).

Description

[0001] The present invention relates to an endoscope device, in particular an endoscope device for hyperspectral and / or multispectral imaging, a correction pair assembly for a lens assembly of an endoscope, an endoscope and an imaging system having an endoscope.

[0002] From the prior art, a lens assembly for an endoscope having a plurality of rod lenses is known. Such a lens assembly is combined with an objective lens and an eyepiece. Light entering the objective lens from the observed object can be transmitted to the eyepiece through the lens assembly. Thus, the observed object can be imaged in a known manner.

[0003] In the field of endoscopy, endoscopic devices that generate multispectral or hyperspectral images are increasingly used. Multispectral or hyperspectral images have, in addition to the two spatial dimensions that conventional camera images have, for example, a spectral dimension. The spectral dimension includes a plurality of spectral bands (wavelength bands). Multispectral and hyperspectral images differ substantially in the number and width of their spectral bands. In principle, such systems can also be adapted to perform fluorescence image acquisition.

[0004] Some imaging devices for producing such multispectral or hyperspectral images are known, in particular in the context of medical applications. For example, DE 20 2014 010 558 U1 describes a device for acquiring a hyperspectral image of an examined area of ​​a body. An input objective for producing an image in an image plane and a slit-shaped aperture in the image plane for delimiting a slit-shaped area in the image are arranged in the device. The light passing through the aperture is fanned out by means of a dispersive element and is acquired by means of a camera sensor. Thus, the camera sensor can acquire multiple spectra along the longitudinal direction of the slit-shaped aperture, each of which has its own assigned spatial coordinates. The described device is also configured to acquire additional spectra in a direction different from the longitudinal direction of the slit-shaped aperture, along the longitudinal direction of the slit-shaped aperture. The method for producing multispectral or hyperspectral images based on this disclosure is also referred to as the so-called pushbroom method.

[0005] In addition to the push-broom method, there are other methods for producing multi-spectral or hyperspectral images. In the so-called Whiskbroom method, the inspected area or object is scanned point by point and a spectrum is obtained for each point. In contrast, in the Staring method, multiple images with the same spatial coordinates are collected. Here, different spectral filters and / or illumination sources are used to resolve spectral information for each image. In addition, there are methods according to which two-dimensional polychromatic images are decomposed into multiple spectral single images by suitable optical elements (such as optical splitters, lenses and prisms), which are detected simultaneously on different detectors or detection areas. This is sometimes referred to as a snapshot method.

[0006] As described in DE 10 2020 105 458 A1, multispectral and hyperspectral imaging devices are particularly suitable as endoscopic imaging devices. In this context, multispectral and / or hyperspectral imaging is an important field of application, for example for diagnosis and for assessing the success or quality of an operation.

[0007] The multimodal endoscopic device allows selective acquisition of white light images and / or multispectral images and / or fluorescence images and / or hyperspectral images.

[0008] For the above-mentioned application scenarios, it is advantageous or even necessary to be able to transmit and image light in the visible range and in the near infrared range. For example, multispectral or hyperspectral imaging is particularly widely used when it is possible to work in a spectral range of about 450nm to 1000nm. It is also advantageous for fluorescence imaging to have a wide spectral range, because in this way the same optical system can be used to collect fluorescence images and white light images. The latter usually reveals the observed anatomical structure more comprehensively, so it makes sense to combine it with the fluorescence image. In this regard, existing lens assemblies often cannot provide satisfactory imaging quality over a wide spectral range. Therefore, in certain parts of the entire spectral range used, it is usually necessary to work with lower resolution or defective focusing.

[0009] Furthermore, it is often unsatisfactory for users to work with a focus optimized for the near-infrared range with attendant loss of focus in the visible light range, since the image quality is then subjectively perceived as insufficient.

[0010] In practice, it is impractical for the user to subsequently adjust the focus of the endoscope device used according to the corresponding observation mode in many cases. If a superimposed diagram should be generated, for example, by superimposing a white light image and a fluorescence image, or a white light image and a hyperspectral image / multispectral image on each other, then switching is performed automatically and at very short time intervals when necessary. Fluorescence imaging and multispectral imaging can be performed in real time. Hyperspectral imaging is usually at least substantially performed in real time, and the acquisition of a hyperspectral image data set lasts for several seconds, for example. However, all wavelengths are taken into account when performing a single image acquisition, so it is impractical to subsequently adjust the focus according to the wavelength.

[0011] Based on the prior art, the present invention is based on the object of achieving high-quality endoscopic imaging in a wide spectral range.

[0012] According to the invention, this object is achieved by an endoscopic device, a correction pair assembly for an endoscope's lens assembly, an endoscope and an imaging system as described herein and defined in the claims.

[0013] An endoscopic device, in particular an endoscopic device for hyperspectral and / or multispectral imaging, comprises a lens assembly defining an optical axis and configured to optically couple an eyepiece to an objective lens. In particular, for a given focus, the lens assembly is configured to achieve at least substantially equivalent light transmission and / or imaging in the visible range and in the near infrared range, and in particular over a large portion of the visible range and in the near infrared range. The lens assembly is symmetrical about a first symmetry plane perpendicular to the optical axis.

[0014] The lens assembly includes at least six rod lenses and at least two correcting elements, which together with the rod lenses define an optical system, and each of the correcting elements includes a lens system having at least a first lens and a second lens. The first lens is made of a first lens, and the second lens is made of a second lens. The first lens and the second lens have different Abbe numbers. The relative partial dispersion of the first lens and the relative partial dispersion of the second lens deviate from the lens with normal dispersion in an opposite manner. In addition, the lens assembly includes at least one correction pair assembly, which includes two of the correction elements, which are symmetrical to each other about a second symmetry plane perpendicular to the optical axis.

[0015] The present invention also relates to a correction pair assembly of a lens assembly for an endoscope, the correction pair assembly comprising at least two correction elements, which define an optical axis and are configured to define an optical system together with a plurality of rod lenses, and each correction element comprises a lens system having at least a first lens and a second lens. The first lens is made of a first lens, and the second lens is made of a second lens. The first lens and the second lens have different Abbe numbers. The relative partial dispersion of the first lens and the relative partial dispersion of the second lens deviate from the lens with normal dispersion in opposite ways. The correction elements are symmetrical to each other about a symmetry plane perpendicular to the optical axis.

[0016] According to the features of the present invention, high-quality endoscopic imaging can be achieved over a wide spectral range. The inventors have recognized that in order to achieve high imaging quality over a wide spectral range, lens errors must be addressed in a very targeted manner and that optical components must be appropriately selected and combined for this purpose. By using paired correction elements and using suitable symmetry on the lens assembly structure, chromatic aberrations can be advantageously reduced, thereby enabling the acquisition of images with high imaging quality in the visible light range and the near-infrared range without the need for subsequent adjustment / regulation of the focus according to the wavelength. In addition, the inventors have recognized that, in particular for high-quality multi-spectral or hyperspectral imaging, if possible, the highest possible light intensity should be present on the corresponding detection sensor device over the entire imaging spectral range. In addition, the use of rod lenses and additional correction elements makes it possible to produce endoscopes or endoscope shafts using conventional assembly methods, in which an endoscopic device or lens assembly according to the present invention is used. The lens system can be constructed using known method steps, with only the combined optical components being different from the existing lens assembly.

[0017] The objective lens may include a lens system configured to enable the coupling-in of light and to transmit the coupled-in light to the lens assembly. The coupled-in light is, for example, light transmitted back and / or emitted by the observed object. In particular, it may be transmitted-back illumination light and / or fluorescence.

[0018] In some embodiments, the eyepiece is configured to supply light transmitted by the lens assembly to an image detection sensor device. The image detection sensor device can be a component of an imaging unit, in particular a multimodal imaging unit, by means of which multispectral imaging, hyperspectral imaging, white light imaging and / or fluorescence imaging are preferably selectively performed.

[0019] The endoscopic device can be a component of an endoscope, in particular a medical endoscope. Typically, it can be a medical endoscopic device. In addition to the endoscopic device, the endoscope can include an eyepiece and / or an objective lens. Alternatively or additionally, the eyepiece and / or the objective lens can be a part of the endoscopic device.

[0020] Multispectral imaging may in particular relate to imaging in which at least two, in particular at least three and in some cases at least five spectral bands are independently detectable and / or to be detected. The individual spectral bands of multispectral imaging may be defined by suitable and, if necessary, switchable optical filters. Hyperspectral imaging may in particular relate to imaging in which at least 20, at least 50 or even at least 100 spectral bands are independently detectable and / or to be detected. Hyperspectral imaging may for example be performed according to a push-broom method and / or a swing-broom method and / or a gaze method and / or a snapshot principle.

[0021] The rod lenses can be arranged in particular so that their longitudinal axes are parallel to each other and / or to the optical axis of the lens assembly. Preferably, the longitudinal axis of the rod lenses coincides with the optical axis. The rod lenses and the correction elements can be arranged so that the light transmitted and / or imaged by the lens assembly passes through all rod lenses and all correction elements.

[0022] In some embodiments, the lens assembly can have a length of at least 20 cm, at least 30 cm, or even at least 40 cm. The lens assembly can be rigid. In other words, the components of the lens assembly (e.g., the at least six rod lenses and the at least two correcting elements), in particular all components of the lens assembly, are immovable relative to each other.

[0023] The endoscope device may further include an eyepiece and / or an objective lens. The eyepiece and / or the objective lens may form an imaging optical system together with the lens assembly.

[0024] The endoscopic device may include a shaft in which the lens assembly is housed and / or fastened. In this case, the optical axis may be arranged parallel to and in particular coincide with the longitudinal axis of the shaft. In other words, the shaft, the rod lens, and in particular the correction element may be arranged coaxially.

[0025] "Most of the wavelength range" refers in particular to a preferably continuous wavelength range covering at least 60%, preferably at least 70%, particularly preferably at least 80% and preferably at least 90% of the reference wavelength range. In this context, in particular the range from 400 nm to 750 nm can be understood as the visible light wavelength range. In this context, the term "near infrared range" relates in particular to wavelengths outside the visible light wavelength range. In particular, for a given focus, the lens assembly can be configured to achieve at least substantially equivalent light transmission and / or imaging over most of the visible light range and over a majority of the range from at least 800 nm to 1000 nm. In other words, for a given focus, the lens assembly can be configured to achieve at least substantially equivalent light transmission and / or imaging over a majority of the range from 480 nm to 900 nm and preferably over a majority of the range from 400 nm to 1000 nm.

[0026] "At least substantially equivalent light transmission" can be understood in particular as: for all arbitrarily selectable pairs of intervals in the mentioned wavelength range, the average transmittance in the mentioned wavelength range differs between these intervals by at most 30%, preferably at most 20%, particularly preferably at most 15% and preferably at most 10%, and these intervals have a width of at most 100 nm, at most 50 nm or even at most 10 nm. "At least substantially equivalent light transmission" can include: for all arbitrarily selectable pairs of wavelengths in the mentioned wavelength range, the transmittance in the mentioned wavelength range differs between these wavelengths by at most 30%, preferably at most 20%, particularly preferably at most 15% and preferably at most 10%. Here, "transmittance" refers in particular to the transmittance, i.e. the quotient of the transmitted intensity and the incident intensity. This information relates in particular to such light intensities that the transmittance is independent or at least substantially independent of the intensity.

[0027] “At least substantially equivalent light transmission and imaging” means in particular that the lens assembly can be used both in most of the visible light range and in the near infrared range. In other words, the lens assembly can be used, in particular equivalently, in the visible light range and in the near infrared range for a given focus.

[0028] "Substantially equivalent light transmission" may be understood in particular as: for all arbitrarily selectable pairs of intervals in the mentioned wavelength range, the average transmittance in the mentioned wavelength range differs between these intervals by at most 30%, preferably at most 20%, particularly preferably at most 15% and preferably at most 10%, the intervals having a width of at most 100 nm, at most 50 nm or even at most 10 nm, and in these intervals, in particular the average transmittance is less than 95%, less than 90% or less than 85%. "At least substantially equivalent light transmission" may include: for all arbitrarily selectable pairs of wavelengths in the mentioned wavelength range, the transmittance in the mentioned wavelength range differs between these wavelengths by at most 40%, preferably at most 30%, particularly preferably at most 20% and preferably at most 10%, in the case of these wavelengths, in particular the transmittance is less than 95%, less than 90% or less than 85%. Furthermore, the term may include: there is at least one sub-region of the mentioned wavelength range, in which at least one sub-region the transmittance is greater than 80%, greater than 85% or even greater than 90%. Here, "transmittance" refers in particular to the degree of transmittance, ie the quotient of the transmitted intensity and the incident intensity. This information relates in particular to the light intensity for which the transmittance is independent or at least substantially independent of the intensity. In other words, a sufficiently efficient light transmission can be achieved over the entire wavelength range mentioned.

[0029] "Substantially equivalent light imaging" may be understood in particular as meaning that for all arbitrarily selectable pairs of intervals in the mentioned wavelength range, within the mentioned wavelength range, the average RMS spot radius differs between these intervals by at most a factor of 15, preferably by at most a factor of 10, particularly preferably by at most a factor of 5 and preferably by at most a factor of 3, the intervals having a width of at most 100 nm, at most 50 nm or even at most 10 nm, and in these intervals, in particular the average RMS spot radius ("RMS" stands for "root mean square") exceeds the diffraction limit. "Substantially equivalent light imaging" may include that for all arbitrarily selectable pairs of wavelengths in the mentioned wavelength range, the RMS spot radius differs between these wavelengths by at most a factor of 15, preferably by at most a factor of 10, particularly preferably by at most a factor of 5 and preferably by at most a factor of 3, in the case of these wavelengths, in particular the average RMS spot radius exceeds the diffraction limit. Furthermore, the term may include that there is at least one sub-region of the mentioned wavelength range in which the RMS spot radius is below the diffraction limit. In other words, imaging of sufficiently intense light can be achieved over the entire wavelength range mentioned.

[0030] The term "for a given focus" means in particular that the light injection into the lens assembly does not change, i.e. in the same way for different wavelengths. For example, if the lens assembly is combined with an objective and / or an eyepiece and focused, the focus does not change for light transmission and imaging at different evaluation wavelengths. Such a focus may include a preset and / or presettable focus for a specific wavelength within the mentioned wavelength range, which focus then remains constant over the entire mentioned range.

[0031] The rod lens and / or the correction element can be designed as an at least substantially cylindrical, preferably cylindrical object. The side surfaces of the rod lens and / or the correction element can be in the shape of a cylindrical side surface. The front surface and / or the rear surface of the rod lens and / or the correction element can differ from the cylindrical shape and can be, for example, convexly or concavely curved.

[0032] The rod-shaped lens is preferably elongated. The length that the rod-shaped lens has can be at least 2 times, 3 times, 4 times, 5 times or even 6 times the diameter of the rod-shaped lens, for example. The rod-shaped lens can be designed to be the same or different. In some embodiments, the lens assembly can include a variety of different rod-shaped lens types. These rod-shaped lens types can be different in their size, curvature, refractive behavior, coating, material and / or other parameters.

[0033] In the scope of the present disclosure, the term "lens" may refer to any lens material. In this regard, "lens" should not be limited to silicate lenses or silicon-based lenses, although in some embodiments, the first lens and / or the second lens may be a silicate lens or a silicon-based lens.

[0034] Within the scope of the present disclosure, the Abbe number may be defined as:

[0035] ν d =(n d -1) / (n F -n C ),

[0036] Where n d 、n F and n C is the refractive index of the relevant material in the corresponding Fraunhofer line. For example, the corresponding wavelengths of Fraunhofer lines d, F and C are 587.56nm, 486.13nm and 656.27nm.

[0037] Alternatively, within the scope of the present disclosure, the Abbe number may also be defined as:

[0038] ν e =(n e -1) / (n F' -n C' ),

[0039] Where n e 、n F' and n C' is the refractive index of the relevant material in the corresponding Fraunhofer line. For example, the corresponding wavelengths of the Fraunhofer lines e, F' and C' are 546.07nm, 479.99nm and 643.85nm.

[0040] The above relative partial dispersion may generally be the relative partial dispersion for two wavelengths x, y, which may be defined as follows:

[0041] P x,y =(n x -n y ) / (n F -n C ),

[0042] Where n x and n y represents the refractive index at wavelengths x and y. In particular, the relative partial dispersion of the first lens and the second lens may be P g,F , where g and F represent the corresponding Fraunhofer lines. For example, the corresponding wavelengths of the Fraunhofer lines g, F, and C' are 435.83 nm and 486.13 nm.

[0043] Lenses with normal dispersion are to be understood in particular as lenses whose relevant relative partial dispersion and Abbe number are linearly dependent, i.e. in particular in ν d -P x,y Lenses that lie on the straight line in the graph for which the following relationship holds:

[0044] P x,y =a x,y +b x,y ·ν d ,

[0045] where a x,y and b x,y is a dimensionless constant belonging to the partial dispersion determined by x and y. ν e It can also be expressed in a similar way. g,F , these constants are known as a g,F =0.6438 and b g,F =0.001682. Such lenses are often referred to as "normal lenses". Their outstanding feature is that light is dispersed in the same way regardless of the spectral range.

[0046] In contrast, lenses that deviate from lenses with normal dispersion may exhibit different dispersion behavior in different spectral ranges, for example, stronger or weaker dispersion in the short-wave range than in the long-wave range. Such lenses are sometimes referred to as lenses with anomalous dispersion.

[0047] It should be understood that these concepts should not be equated with the concepts of normal dispersion and anomalous dispersion used in part, which relate to the basic dispersion behavior of the material, i.e. the refractive index increases with frequency ("normal dispersion") or decreases with frequency ("anomalous dispersion"). Rather, the lens characteristics described herein relate, where necessary, to different derivatives of dispersion at different wavelengths, which may have the same sign.

[0048] The relative partial dispersion of the first lens and the second lens deviates in particular in the opposite way from the lens with normal dispersion as follows: d -P x,y In the diagram, the first lens is located on one side of the normal dispersion lens line, and the second lens is located on a second side opposite to the first side. Similarly, this can be applied to ν de -P x,y The deviation parameter ΔP can be defined as follows x,y :

[0049] ΔP x,y =(n x -n y ) / (n F -n C)-a x,y +b x,y ·ν d .

[0050] ν e It can also be expressed in a similar way. For the first lens and the second lens, the deviation parameter ΔP x,y The signs of the values ​​of can be different.

[0051] The first lens may consist at least mostly and / or completely of the first lens. The second lens may consist at least mostly and / or completely of the second lens. "At least mostly" may mean at least 55%, preferably at least 65%, preferably at least 75%, particularly preferably at least 85% and very particularly preferably at least 95%, more precisely in particular in relation to the volume and / or mass of the object.

[0052] Preferably, the first lens and the second lens are arranged directly one after the other and in particular in contact with one another and / or are formed integrally with one another, for example optically bonded and / or adhesively bonded.

[0053] The correction elements of the correction pair assembly can be arranged symmetrically with respect to the second symmetry plane. The correction elements of the correction pair assembly can be designed to be identical and, for example, can only be rotated relative to each other to produce symmetry. In other embodiments, the correction elements can be designed to be different but symmetrical with each other.

[0054] When the first symmetry plane and the second symmetry plane coincide, a simple optical structure can be achieved in particular. Thus, optical modeling for adjusting the lens assembly can be performed particularly easily. In other embodiments, the first symmetry plane and the second symmetry plane can be spaced apart from each other along the optical axis.

[0055] In some embodiments, the lens assembly includes at least one additional correction pair assembly, wherein the additional correction pair assembly includes two other correction elements of these correction elements, and the other two correction elements are symmetrical to each other about a third symmetry plane perpendicular to the optical axis. Thus, a high degree of imaging quality and imaging stability can be achieved. The additional correction pair assembly can be designed to be the same as the correction pair assembly. Alternatively, these correction pairs can be different, for example, in the correction elements used and / or their relative positions and / or orientations.

[0056] When the second and third symmetry planes differ from the first symmetry plane, in particular a high degree of flexibility in the design of the lens assembly and the associated various possibilities for achieving a high imaging quality can be achieved. The second and third symmetry planes can be consistent. Alternatively, it can be proposed that the second symmetry plane is different from the third symmetry plane. These symmetry planes can be spaced apart from each other along the optical axis. In a further embodiment, the first and third symmetry planes can be consistent with each other, but different from the second symmetry plane.

[0057] Within the scope of the present disclosure, mutually different planes of symmetry may be spaced apart from each other by a distance of at least 1 cm, at least 2 cm, at least 5 cm, at least 10 cm or even at least 20 cm along the optical axis.

[0058] It can also be proposed that each of these correction elements comprises at least a third lens. In some embodiments, the third lens is made of the first lens and / or the second lens. In other embodiments, the third lens can also be made of a third lens that is different from the first lens and / or the second lens. In particular, the third lens can be different from a lens that exhibits normal dispersion in the sense of the present disclosure. The third lens can be at least mostly and / or completely composed of the first lens, the second lens or the third lens. Here, the second lens can be arranged between the first lens and the third lens. Preferably, the first lens, the second lens and the third lens are arranged directly one after the other and in particular in contact with each other and / or are formed integrally with each other, for example optically bonded and / or adhesively bonded.

[0059] When the correction elements are formed integrally with the rod lenses, respectively, the assembly workload and / or the number of parts can be reduced in particular. Generally speaking, at least one of these correction elements can be formed integrally with at least one of these rod lenses. Here, "integrally" includes one-piece and single-piece. At least one lens of the relevant correction element can be formed integrally with the relevant rod lens. Preferably, all lenses of the relevant correction element are formed integrally with the relevant rod lenses. For example, in these cases, the first lens can be arranged adjacent to the rod lens and / or optically bonded and / or bonded thereto. The arrangement can also be reversed so that the second lens is arranged adjacent to the rod lens. Then, the second lens can also be arranged adjacent to the first lens and / or optically bonded and / or bonded thereto. In some embodiments, the correction element can be placed on the flat surface of the rod lens and / or bonded and / or bonded thereto.

[0060] In addition, the correction pair assembly may include at least one aperture, which is arranged in the region of the second plane of symmetry. Thus, the aperture of the lens assembly can be conveniently placed. In some variants, the second plane of symmetry intersects with the aperture. In particular, the aperture has a smaller diameter than the rod lens and / or the correction element and / or the lens of the correction element. Information about the symmetry of the lens assembly can particularly relate to the parts of the lens assembly without an aperture (i.e., ignoring the aperture). In other words, the lens assembly can be symmetrical without an aperture, but the aperture can be arranged, for example, off-center. In principle, multiple apertures can also be provided. These apertures can be arranged symmetrically to each other about one or any or all of the mentioned planes of symmetry and / or each can be formed symmetrically relative to the planes of symmetry.

[0061] Depending on the design of the lens assembly or of the optical system defining the rod lens and the correction element, at least one of the first lenses and / or at least one of the second lenses may be a convex lens. Alternatively or additionally, at least one of the first lenses and / or at least one of the second lenses may be a concave lens. The second lenses may be designed to be identical. The first lenses may be designed to be identical.

[0062] If the lens assembly enables optical imaging in the range of 400 nm to 1000 nm, which has an RMS spot radius of at most 40 μm, preferably at most 35 μm and preferably at most 30 μm, a high image quality can be achieved in particular over a large spectral range. This can in particular mean that for each arbitrarily selected interval in this range with a width of at most 50 nm, preferably at most 40 nm, particularly preferably at most 30 nm and preferably at most 20 nm, the average RMS spot radius is at most 40 μm, preferably at most 35 μm and preferably at most 30 μm. This can also mean that for each arbitrary wavelength, the RMS spot radius is at most 40 μm, preferably at most 35 μm and preferably at most 30 μm.

[0063] In some embodiments, the lens assembly can achieve diffraction-limited optical imaging in the range of 480 nm to 1000 nm. In other words, the lens assembly can be designed to achieve diffraction-limited optical imaging for each arbitrary wavelength in the range of 480 nm to 1000 nm. Diffraction-limited optical imaging is particularly characterized by a calculated RMS spot radius that is less than or equal to a value defined by the diffraction limit.

[0064] In particular, in the range of 480 nm to 1000 nm, the lens assembly may have a maximum RMS spot radius of at most 8 μm, preferably at most 6 μm and preferably at most 4 μm. In other words, for each arbitrary wavelength, in particular in the range of 480 nm to 1000 nm, the RMS spot radius may be at most 8 μm, preferably at most 6 μm and preferably at most 4 μm.

[0065] The inventors have also recognized that conventional lens assemblies, although sometimes having good transmittance in the visible light range, exhibit significantly poor transmittance in the near infrared range. Therefore, the availability of such conventional lens assemblies, especially for multi-spectral applications and hyperspectral applications, is significantly limited, in which imaging should also be performed in the near infrared range. In particular, when the rod lens and the correction element have anti-reflection surfaces that work in the visible light range and the near infrared range, high-quality imaging can be achieved in a wide spectral range. In other words, the anti-reflection surface can be designed to: compared with the anti-reflection surface that optimizes the transmittance only in the visible light range, although a slightly lower transmittance may be accepted, the transmittance outside the visible light range remains at a high level, rather than rapidly decreasing. The anti-reflection surface may include a coating of the relevant optical element, such as an anti-reflection coating. Alternatively or additionally, the surface of the relevant optical element itself may also be processed, such as microscopic and / or nanoscale roughening.

[0066] In particular, it can be provided that the antireflection surface each causes an average reflectivity of at most 2%, preferably at most 1% and preferably at most 0.6% in the range of 400 nm to 1000 nm. Alternatively or additionally, it can be provided that the antireflection surface each causes a maximum reflectivity of at most 3%, preferably at most 2% and preferably at most 1% in the range of 400 nm to 1000 nm.

[0067] The anti-reflection surface may be present on at least one surface of at least one optical element of the lens assembly, for example on at least one rod lens and / or on at least one correcting element, such as at least one of these lenses. Preferably, at least a plurality of (preferably all) of the existing surfaces are provided with an anti-reflection surface.

[0068] The lens assembly may have an average transmittance of at least 70%, preferably at least 80%, and particularly preferably at least 85% in the range of 400 nm to 1000 nm. Alternatively or additionally, the lens assembly may have a minimum transmittance of at least 60%, preferably at least 70%, and particularly preferably at least 80% in the range of 400 nm to 1000 nm. Thus, light transmission may be achieved over a wide spectrum through the entire lens assembly, so that light may be effectively transmitted in the visible light range and the near infrared range.

[0069] The present invention also relates to an endoscope having an endoscopic device according to the present invention and / or having a correction pair assembly according to the present invention. In some embodiments, the endoscope is configured to be inserted into a cavity (e.g., an artificial cavity and / or a natural cavity, such as the interior of the human body, a body organ, a tissue, etc.) for inspection and / or observation. The endoscope can also be configured to be inserted into a housing, a shield, a well, a pipeline or another (especially artificial) structure for inspection and / or observation.

[0070] Furthermore, the present invention relates to an imaging system, in particular a medical imaging system. The imaging system comprises an illumination device, which is configured to provide illumination light in the visible light range and the near infrared range. Furthermore, the imaging system comprises an endoscopic device according to the present invention and / or an endoscope according to the present invention. Furthermore, the imaging system comprises an imaging device, which has an image detection unit, which is configured to detect multispectral and / or hyperspectral image data. The image detection unit may include an image detection sensor device.

[0071] The imaging system may be multimodal. In particular, the imaging system may be configured to selectively acquire white light images and / or multispectral images and / or fluorescence images and / or hyperspectral images.

[0072] The image detection sensing device can be configured to detect light in the visible light range and the near infrared range. In some embodiments, the minimum detectable wavelength can be at most 500nm, at most 450nm, or even at most 400nm. In some embodiments, the maximum detectable wavelength can be at least 800nm, at least 900nm, or even at least 1000nm. The image detection sensing device can include, for example, at least one white light image sensor and at least one near infrared image sensor. In some embodiments, the imaging device includes a white light camera and / or a sensing device for detecting white light images. The imaging device can be configured for white light imaging. Anatomical images can be collected with the aid of a white light camera and / or a sensing device for detecting white light images.

[0073] The image detection unit may have a filter unit with an optical observation filter. The filter unit may define a plurality of fluorescence modes defined by different observation filters. For example, different edge filters may be used which absorb / block the respective used spectrum of the relevant light emitting element for excitation and transmit only fluorescence at least substantially. Thus, the observation filter that blocks light in the first spectral range is part of the filter unit. In some embodiments, the observation filter may also be switched between a multi-spectral mode and a fluorescence mode.

[0074] The imaging device and in particular an optical device and / or an image detection sensor device can be configured for multispectral and / or hyperspectral imaging, in particular for detecting and / or generating multispectral and / or hyperspectral image data. Here, multispectral imaging or multispectral image data can in particular refer to such imaging, wherein at least two, in particular at least three and in some cases at least five spectral bands can be detected and / or will be detected independently of each other. Here, hyperspectral imaging or hyperspectral image data can in particular refer to such imaging, wherein at least 20, at least 50 or even at least 100 spectral bands can be detected and / or will be detected independently of each other. The imaging device can work according to the push-broom method and / or the swing-broom method and / or the gaze method and / or the snapshot principle.

[0075] For some applications, it may be advantageous to use a high spectral resolution. Thus, hyperspectral imaging is meaningful. Hyperspectral imaging can be combined with white light imaging. Thus, even if the detection of spectrally resolved image data is only substantially carried out in real time (i.e., for example, it takes several seconds to create a spectrally resolved image), real-time observation can be performed by means of white light images. For some applications, it may be advantageous to generate spectral image data in real time. This, for example, includes generating a spectrally resolved image in less than a second or even multiple times per second. Here, it may be convenient to adopt multispectral imaging. In this case, a lower spectral resolution is exchanged for a higher image refresh rate if necessary. Depending on the application, it may be sufficient to consider only a few different spectral ranges and / or wavelengths (e.g., two, three, four, or generally less than ten). Here, additional white light imaging can be selectively omitted. Spectrally resolved image data acquired in real time or providing multiple images per second can also be used for monitoring purposes, where it is not necessary to create a playable image for the user, but the image data can also be processed in the background.

[0076] The image detection sensor device has in particular at least one image sensor. In addition, the image detection sensor device can also have at least two and preferably more image sensors, which can be arranged one after another. In addition, these two and preferably more image detection sensors can have spectral detection sensitivities designed to be different from each other, so that, for example, the first sensor is particularly sensitive in the red spectral range, the second sensor is in the blue spectral range, and the third sensor is in the green spectral range, more precisely, relatively more sensitive than other sensors. The image sensor can, for example, be designed as a CCD sensor and / or a CMOS sensor.

[0077] The image acquisition unit is particularly configured to generate at least two-dimensional spatial image data. The image acquisition unit can have a spatial resolution such that the image acquisition unit provides a resolution of at least 100 pixels, preferably at least 200 pixels, preferably at least 300 pixels and advantageously at least 400 pixels in at least two different spatial directions. The image data is preferably at least three-dimensional, wherein at least two dimensions are spatial dimensions and / or wherein at least one dimension is a spectral dimension. A plurality of spatially resolved images of an image region correspondingly assigned to different spectral bands can be acquired from the image data. The spatial information and spectral information of the image data can be constructed in such a way that, based on this information, relevant spectra are acquired for a plurality of spatial image points, respectively.

[0078] In some embodiments, the image detection unit is configured to generate continuously updated image data. The image detection unit can, for example, be configured to generate image data substantially in real time, which for example includes generating updated image data at least every 30 seconds, in some cases at least every 20 seconds, and in some cases even at least every 10 seconds or at least every 5 seconds. Preferably, the image detection unit is configured to generate at least anatomical images and fluorescent images and illustrations based on these images in real time, for example at a frame rate of at least 5fps, at least 10fps, at least 20fps or even at least 30fps.

[0079] The lighting device may be designed to be multimodal and include a plurality of light emitting elements that are independent of each other and can be selectively enabled, and the light emitting elements are configured to emit light according to different emission spectra to provide illumination light.

[0080] The lighting device may include an optical interface for optically coupling an endoscope. The lighting unit may be configured to provide illumination light to the optical interface. The lighting unit may be designed to be multimodal and include a plurality of light-emitting elements that are independent of each other and can be selectively enabled, and these light-emitting elements are configured to emit light according to different emission spectra to provide illumination light. The lighting unit may operate in at least one multi-spectral mode, in which a first group of light-emitting elements is at least temporarily enabled, and in which at least one multi-spectral mode, the lighting unit provides illumination light for multi-spectral imaging. In addition, the lighting unit may operate in at least one fluorescent mode, in which a second group of light-emitting elements is at least temporarily enabled, and in which at least one fluorescent mode, the lighting unit provides illumination light for fluorescent imaging. The light-emitting elements may include at least one light-emitting element, and the at least one light-emitting element is included in both the first group and the second group.

[0081] In addition, a method for generating illumination light for an imaging device by means of an illumination device can be provided. Here, the illumination device includes an optical interface for optically coupling an endoscope and an illumination unit, the illumination unit being configured to provide illumination light to the optical interface, wherein the illumination unit includes a plurality of light-emitting elements that are independent of each other and can be selectively enabled, and these light-emitting elements are configured to emit light according to different emission spectra to provide illumination light. The method includes the steps of at least temporarily enabling a first group of light-emitting elements to provide illumination light for multi-spectral imaging, and at least temporarily enabling a second group of light-emitting elements to provide illumination light for fluorescent imaging. At least one of the light-emitting elements is at least temporarily enabled when the first group of light-emitting elements is at least temporarily enabled and when the second group of light-emitting elements is at least temporarily enabled.

[0082] The optical interface can be selectively disconnected and connected. In addition, the optical interface can be combined with the mechanical interface so that the optical connection is automatically established when the endoscope is mechanically coupled.

[0083] The light-emitting elements may include monochromatic LEDs (light-emitting diodes) and / or laser diodes. In addition, at least one of these light-emitting elements may be a white light LED or another white light source. In some embodiments, the lighting unit includes at least one blue light-emitting element, at least one red light-emitting element, at least one dark red light-emitting element, and at least one near-IR light-emitting element (near-infrared light-emitting element), which are in particular LEDs or laser diodes, respectively. In addition, the lighting unit may include at least one white light LED or another white light source.

[0084] The first group may include at least two light-emitting elements that emit light differently in the spectrum. When the multi-spectral mode includes correspondingly at least temporarily enabling different states of a specific light-emitting element or a specific light-emitting element type, high efficiency can be achieved in the case of multi-spectral imaging. Thus, illumination can be carried out in a targeted manner within a specific spectral range, thereby detecting different spectral images. Different light-emitting elements enabled in different states can be used as different support points for multi-spectral imaging. At least one of these support points can be selected in such a way that it is adapted to a characteristic point of the absorption spectrum of a physiologically relevant component, such as an isosbestic point of the hemoglobin oxygenation curve. Multi-spectral imaging may also include the use of a suitable observation filter.

[0085] In addition, the second group may include at least two light-emitting elements that emit light differently in the spectrum. The fluorescence mode may include different sub-modes and / or states, in which a specific light-emitting element or a specific light-emitting element type is correspondingly enabled at least temporarily. Thus, it is possible to excite in a specific spectral range in a targeted manner, so that fluorescence imaging of a dye selected specifically can be achieved, for example. In other words, the at least one light-emitting element included in the first group and the second group can be used for multi-spectral mode and fluorescence mode simultaneously.

[0086] In some embodiments, the first group includes only some but not all of the light-emitting elements. Alternatively or additionally, in some embodiments, the second group includes only some but not all of the light-emitting elements. In multi-spectral mode, in particular only the light-emitting elements of the first group are enabled at least temporarily, while the light-emitting elements that do not belong to the first group are not enabled. In fluorescence mode, in particular only the light-emitting elements of the second group are enabled at least temporarily, while the light-emitting elements that do not belong to the second group are not enabled. In general, it should be understood that the light-emitting elements may include different light-emitting element types; and in particular there is exactly one light-emitting element in each of these different light-emitting element types. It should be understood that according to the present invention, there may also be a mixed operating mode, in which the mentioned modes are used sequentially. For example, multi-spectral imaging and fluorescence imaging can be performed sequentially.

[0087] In particular, when at least one light-emitting element simultaneously included in the first group and the second group emits light in the red spectral range, in particular in the spectral range between 600nm and 680nm, for example 610nm to 650nm or 620nm to 660nm or 630nm to 670nm, a synergistic effect of using light source elements for different modes and efficiency gains associated therewith can be achieved. The spectral range can be narrow-band and the wavelength can include 660nm. "Narrow-band" can include a spectral width of at most 80nm, in particular at most 40nm or even at most 20nm. The at least one light-emitting element can be configured to excite an absorbing dye in the red spectral range and provide illumination in the red spectral range for multi-spectral imaging.

[0088] In some embodiments, the lighting unit can operate in at least one white light mode, in which the lighting unit provides illumination light for white light imaging. The illumination light for white light imaging can be broadband white light. Alternatively, the illumination light for white light imaging can include multiple narrow wavelength bands separated from each other, such as a blue band, a red band, and a dark red band. Here, "dark red" should be understood in the sense of "longer than red wavelength" and refers to spectral position rather than light intensity. The illumination light for white light imaging can be a mixture of light from different light-emitting elements.

[0089] In the white light mode, the third group of light emitting elements may be enabled at least temporarily to provide illumination light for white light imaging. Here, the light emitting element may include at least one light emitting element, which is simultaneously included in the first group and / or the second group and the third group. In some cases, the third group may include only some but not all light emitting elements. In the white light mode, in particular, only the light emitting elements of the third group are enabled at least temporarily, while the light emitting elements that do not belong to the third group are not enabled. In other words, the lighting unit may include light emitting elements for one, two or all three of the above-mentioned lighting modes. Thus, multiple light emitting elements can be used multiple times.

[0090] At least one light-emitting element included in the first group and / or the second group and the third group can emit light in the red spectral range, especially in the spectral range between 600nm and 680nm, for example, 610nm to 650nm or 620nm to 660nm or 630nm to 670nm. When at least one red light-emitting element can be used for all three modes, the advantage of using light-emitting elements together is particularly obvious.

[0091] At least one light emitting element included in the first group and / or the second group and the third group can emit light in the blue spectral range, especially in the spectral range between 440nm and 480nm. At least one blue light emitting element can be used in both the fluorescent mode and the white light mode.

[0092] In general, as described above, the light-emitting element may include at least one particularly blue light-emitting element, which emits light in a spectral range between 440nm and 480nm. In addition, as described above, the light-emitting element may include at least one particularly red light-emitting element, which emits light in a spectral range between 600nm and 680nm, for example between 610nm and 650nm or between 620nm and 660nm or between 630nm and 670nm. Alternatively or additionally, the light-emitting element may include at least one particularly dark red light-emitting element, which emits light in a spectral range between 750nm and 790nm. Alternatively or additionally, the light-emitting element may include at least one particularly near-IR luminescent light-emitting element, which emits light in a spectral range between 920nm and 960nm. In addition, the light-emitting element may include a white light-emitting element. In particular, when at least one light-emitting element is present in each of the above-mentioned light-emitting element types, a compact and versatile lighting unit can be provided. For example, in fluorescence mode, blue and red light-emitting elements can be used, and dark red light-emitting elements can also be used if the dye is suitable. In multispectral mode, dark red and near-IR light-emitting elements can be used. In white light mode, white light-emitting elements can be used. In white light mode, white light-emitting elements can be supplemented by blue light-emitting elements and, if necessary, also by red light-emitting elements. Thus, white light-emitting elements can be supplemented by means of colored light-emitting elements, for example, due to their structure, but in particular due to filters and optical elements of the illumination unit, which provide a wavelength range with lower intensity. In addition, colored light-emitting elements can be used to adjust the color temperature during white light imaging.

[0093] In some embodiments, the second group includes a single light-emitting element and / or a single type of light-emitting element. For example, a white light-emitting element, a red light-emitting element and an IR light-emitting element can be provided, wherein with regard to possible spectral ranges, reference is made in particular to the above values. Thus, the first group can, for example, include red and IR light-emitting elements. The second group can include an IR light-emitting element, in particular as the only light-emitting element or as the only type of light-emitting element.

[0094] In particular, when the lighting unit includes at least one cross beam splitter by which light can be deflected from the relative input side to the output side, an advantageous arrangement of light-emitting elements can be achieved, wherein at least one of these light-emitting elements is arranged at the relative input side of the cross beam splitter. In some embodiments, two or even more cross beam splitters can be provided, which are optically arranged one after another. The at least one cross beam splitter can include two beam splitter elements, the transmittance of which is adapted to the light-emitting elements assigned accordingly. The beam splitter elements in particular each include a notch filter so that they each reflect in a narrow spectral band, rather than transmit. The spectral position and / or width of the corresponding notch can be adapted to the spectral range of the light-emitting element assigned accordingly, so that the light of the light-emitting element is deflected, but the light of other light-emitting elements is at least substantially transmitted.

[0095] In some embodiments, the light emitting element may include at least four narrow-band emitting monochromatic light emitting elements each having a different spectral range and at least one broadband emitting white light emitting element. In this regard, reference is also made to the above embodiments regarding colored light emitting elements.

[0096] In particular, when the lighting unit can be operated in at least one hyperspectral mode, a combination of wide functionality, compact structure, and full use of synergistic effects when using light-emitting elements can be achieved, in which at least one hyperspectral mode, multiple light-emitting elements are enabled, and the emission spectra of these light-emitting elements jointly cover a spectral range of at least 450nm to 850nm, and in which at least one hyperspectral mode, the lighting unit provides illumination light for hyperspectral imaging. This can particularly involve all light-emitting elements.

[0097] It is understood that, in particular when using laser diodes, polarization filters suitable for the optical filters mentioned here can be used. In addition, in particular when using laser diodes, at least one cross beam splitter can be used, the beam splitter element of which is provided with a polarization filter. Thus, selective transmission can be achieved by combining different polarizations.

[0098] The device and system according to the invention as well as the method according to the invention are not limited to the above-mentioned applications and embodiments. In particular, in order to meet the working method described here, these devices, systems and methods can have a number of individual elements, components and units and method steps that differ from the number mentioned in this article. In addition, the values ​​within the mentioned limits in the value range given in this disclosure should also be regarded as disclosed and can be used arbitrarily.

[0099] In particular, it is to be pointed out that all features and characteristics described with respect to the device, but also the means, can be meaningfully transferred to the method and can be used in the sense of the present invention and are considered to be jointly disclosed. The same applies vice versa. This means that structural features mentioned with respect to the method (i.e. device-related features) can also be considered and claimed within the scope of the device claim and also belong to the disclosure.

[0100] In the following, the invention is described exemplarily with the aid of the accompanying drawings. The drawings, the description and the claims contain a combination of multiple features. Conveniently, a person skilled in the art can also consider these features individually and reasonably combine them within the scope of the claims.

[0101] If more than one example of an object exists, only one of the examples is provided with a reference numeral in the drawings and the description, if necessary. The description of this example can be transferred to the other examples of the object accordingly. If the objects are named, in particular, with the aid of numerals (e.g. first, second, third object, etc.), these numerals are used to name and / or assign the objects. Thus, for example, the first object and the third object can be included, but the second object is not included. However, it is also possible to additionally deduce the number and / or sequence of the objects with the aid of the numerals.

[0102] In the attached picture:

[0103] Figure 1 A schematic illustration of an imaging system is shown, which has an illumination device, an endoscope with an endoscope device, and an image detection device;

[0104] Figure 2 A schematic diagram showing a lens assembly of an endoscopic device according to the prior art;

[0105] Figure 3 shows a schematic illustration of line pattern imaging performed with a lens assembly according to the prior art;

[0106] Figure 4 A graph showing the wavelength dependency of the RMS spot radius of a lens assembly according to the prior art;

[0107] Figure 5 A schematic illustration of a first endoscopic device is shown;

[0108] Figure 6 A schematic illustration showing a calibration pair assembly of a first endoscopic device;

[0109] Figure 7 A diagram illustrating the selection of lenses for a corrective pair assembly is shown;

[0110] Figure 8 showing a schematic illustration of a second endoscopic device;

[0111] Fig. 9 a schematic illustration showing a calibration pair assembly of a second endoscopic device;

[0112] Fig.10 A schematic illustration of a third endoscopic device is shown;

[0113] Fig.11 a schematic illustration showing a calibration pair assembly of a third endoscopic device;

[0114] Fig.12 A schematic illustration showing line pattern imaging performed with a first endoscopic device, a second endoscopic device, or a third endoscopic device;

[0115] Fig.13 a graph showing wavelength dependency of an RMS spot radius for a first endoscopic device, a second endoscopic device, or a third endoscopic device;

[0116] Fig.14 A schematic illustration showing a lens assembly having an anti-reflective surface;

[0117] Fig.15 shows a schematic diagram illustrating different reflectivity curves;

[0118] Fig.16 shows a schematic diagram illustrating different transmittance curves;

[0119] Fig.17 A schematic diagram showing a lighting device 150; and

[0120] Fig.18 Schematic transmission curve of a beam splitter element of an illumination device is shown.

[0121] Figure 1 A schematic illustration of an imaging system 148 is shown. The imaging system 148 is an endoscopic imaging system. The imaging system 148 may be a medical imaging system. In the present case, the imaging system 148 is a multispectral and / or hyperspectral endoscopic imaging system.

[0122] The imaging system 148 comprises an illumination device 150, an endoscope device 110 and an imaging device 152 having an image detection unit 154. The image detection unit 154 is configured to detect multispectral and / or hyperspectral image data. To this end, the image detection unit 154 comprises a suitable image detection sensor device 158, which is shown only as an example.

[0123] The image detection sensor device 158 may include a CMOS or CCD sensor not shown. The image detection sensor device 158 and, if necessary, related optical elements may be arranged in a push-sweep assembly. In other embodiments, a swing-sweep assembly, a gaze assembly and / or a snapshot assembly are used. For different methods of hyperspectral imaging and the components required for this purpose, reference is made to the professional article "Review of spectral imaging technology in biomedical engineering: achievements and challenges" published by Quingli Li et al. in Journal of Biomedical Optics 18(10), 100901, October 2013 and the professional article "Medical hyperspectral imaging: a review" published by Guolan Lu and Baowei Fei in Journal of Biomedical Optics 19(1), 010901, January 2014.

[0124] In other embodiments, as described above, the image sensing unit 154 may also be multispectral, for example, by filters that can be selectively introduced into the object beam path and / or by sequential illumination with different wavelengths to observe multiple spectral ranges.

[0125] Endoscopic device 110 is part of endoscope 146. Endoscope 146 may include part of image detection unit 154. Endoscopic device 110 includes shaft 160. Shaft 160 is configured to accommodate a lens assembly, which is configured to direct imaging light from a distal end 162 of endoscope device 110 and / or shaft 160 to a proximal end 164 of endoscope device 110 and / or shaft 160. This will be discussed further below. Shaft 160 may be rigid. In particular, endoscope 146 is a rigid endoscope, and / or endoscope device 110 is an endoscope device for a rigid endoscope.

[0126] Figure 2 A schematic diagram of a lens assembly 212 of an endoscopic device 210 according to the prior art is shown. The endoscopic device 212 includes an eyepiece 216 and an objective lens 218. The lens assembly 212 couples the eyepiece 216 to the objective lens 218 in a known manner. Light collected from the objective lens 218 can be transmitted to the eyepiece 216 through the lens assembly 212. Thus, an image can be generated.

[0127] The lens assembly 212 includes a plurality of rod lenses 222. The lens assembly 212 is mainly configured to transmit and image light in the visible light range (eg, in the range of 450 nm to 750 nm).

[0128] Figure 3 A schematic diagram showing an image of a line pattern performed with a lens assembly 212 according to the prior art is shown. Figure 4 A graph showing the wavelength dependence of the RMS spot radius of the lens assembly 212 is shown. As can be seen, the RMS spot radius is smaller in the medium wavelength range and even lower than Figure 4 If the line pattern is imaged, then in the medium wavelength range, for example for light with a wavelength between 486 nm and 656 nm, we obtain Figure 3 The image shown in the middle. A sharp line pattern image can be obtained here because the lens assembly 212 images well in this range. However, due to lens errors, especially due to chromatic aberration, a sharp image cannot be obtained for both smaller and larger wavelengths at the same time. In these ranges, the RMS spot radius is significantly larger, which results in unclear imaging. This is in Figure 3 The left side of the diagram is shown by way of example for a wavelength range of 400 nm to 500 nm, and the right side is shown by way of example for a wavelength range of 800 nm to 1000 nm. In particular in the near infrared range, i.e. in the last-mentioned range, the imaging quality is quite low, so that geometric features cannot be imaged precisely.

[0129] Therefore, the conventional endoscope device 210 is mainly used in the visible light range. If the endoscope device is used for white light imaging, it roughly corresponds to Figure 3 The imaging quality may be sufficient for the combination of the left and middle cases. However, if imaging is also performed in the near infrared, the quality may not be sufficient to obtain convincing image data, from which, for example, the anatomical features of the examined anatomical structure of the patient cannot be evaluated.

[0130] Figure 5 1 shows a schematic diagram of a first endoscope device 110 according to the present disclosure. The first endoscope device 110 can be used in the visible light range and the near infrared range. The endoscope device 110 includes a lens assembly 112, an eyepiece 116, and an objective lens 118. Here, they are arranged in Figure 1 The lens assembly 112 optically couples the eyepiece 116 to the objective lens 118. Therefore, through the lens assembly 112, light can be substantially equivalently transmitted and imaged at least in the range between 480nm and 1000nm, preferably in the range between 400nm and 1000nm.

[0131] The lens assembly 112 includes six rod lenses 122. In addition, the lens assembly 112 includes two correcting elements 124. The lens assembly 112 defines an optical axis 114. The rod lenses 122 and the correcting elements 124 are arranged coaxially with respect to the optical axis 114. In the illustrated case, the rod lenses 122 and the correcting elements 124 each have a circular cross section, the center of which is located on the optical axis 114.

[0132] The lens assembly 112 is symmetric about a first symmetry plane 120. The first symmetry plane 120 is perpendicular to the optical axis 114.

[0133] The two correction elements 124 are part of or constitute a correction pair assembly 134. The two correction elements 124 of the correction pair assembly 134 are symmetrical to each other with respect to a second symmetry plane 136. In this embodiment, the second symmetry plane 136 corresponds to the first symmetry plane.

[0134] Correction pair assembly 134 Figure 6 1. Each of the correction elements 124 of the correction pair assembly 134 includes a first lens 130, a second lens 132 and a third lens 142. These lenses form a lens triplet. The first lens 130, the second lens 132 and the third lens 142 are integrally formed, for example, by bonding and / or optical bonding. Together they form a lens system 128.

[0135] The first lens 130 is made of a first lens, and the second lens 132 is formed of a second lens. The first lens and the second lens are selected in such a way that they deviate from the lens with normal dispersion in opposite ways. Figure 7 Schematically shown in . Figure 7 The relative partial dispersion P is plotted g,F With the Abbe number ν d The solid line defines those points where the lenses with normal dispersion are located. For this purpose, reference is made in particular to the above embodiments with lenses with normal dispersion and anomalous dispersion. In this diagram, the first lens and the second lens are located at the points defined by Figure 7 . The first lens is located to the right of the line with a larger Abbe number and deviates from the lens with normal dispersion in a first direction. The second lens is located to the left of the line with a smaller Abbe number and deviates from the lens with normal dispersion in a second direction opposite to the first direction.

[0136] For example, the Abbe number ν of the first lens d The refractive index is 63.66. D is 1.61800 and the dispersion n F -n C For example, the Abbe number ν of the second lens dThe refractive index is 42.41 and n D is 1.63775 and the dispersion n F -n C is 0.015038. Therefore, the two lenses are intentionally selected to be different and intentionally deviate from normal dispersion in opposite ways. As a result, the lens assembly 112 can provide high-quality imaging over a wide spectral range.

[0137] In this embodiment, the third lens 142 is also made of the first lens.

[0138] The first lens 130 is a concave lens. The second lens 132 is a convex lens. The third lens 142 is a concave lens. Exemplarily, the first lens 130 has a radius of curvature of -6 mm. Furthermore, exemplarily, the second lens 132 has a radius of curvature of 6 mm. Furthermore, exemplarily, the third lens 142 has a radius of curvature of 90 mm.

[0139] The correction pair assembly 134 has an opening 144 which is arranged in the region of the second plane of symmetry 136. The opening 144 has a smaller diameter than the rod lens 112 and the correction element 124.

[0140] Figure 8 A schematic diagram of a second endoscope device 110' according to the present disclosure is shown. In order to be able to distinguish better, the reference numerals of this embodiment are provided with quotation marks. Unless otherwise stated, the existing components can also refer to the above statements in principle. The second endoscope device 110' can be used in the visible light range and the near infrared range. The second endoscope device 110" includes a lens assembly 112', an eyepiece 116' and an objective lens 118'. Here, they are arranged Figure 1 The lens assembly 112' optically couples the eyepiece 116' to the objective lens 118'. Therefore, through the lens assembly 112', light can be substantially equivalently transmitted and imaged at least in the range between 480nm and 1000nm, preferably in the range between 400nm and 1000nm.

[0141] The lens assembly 112' comprises ten rod lenses 122'. In addition, the lens assembly 112' comprises six correcting elements 124'. The lens assembly 112' defines an optical axis 114'. The rod lenses 122' and the correcting elements 124' are arranged coaxially with respect to the optical axis 114'. In the illustrated case, the rod lenses 122' and the correcting elements 124' each have a circular cross section, the center of which is located on the optical axis 114'.

[0142] The lens assembly 112' is symmetrical about a first symmetry plane 120'. The first symmetry plane 120' is perpendicular to the optical axis 114'.

[0143] Two of these correction elements 124' are part of or constitute a correction pair assembly 134'. The two correction elements 124' of the correction pair assembly 134' are symmetrical to each other about a second symmetry plane 136'. In this embodiment, the second symmetry plane 136' corresponds to the first symmetry plane.

[0144] The other two pairs of correction elements in the correction elements 124' respectively form two other correction pair assemblies 138', 168'. The other two pairs of correction elements are symmetrical to each other about the third symmetry plane 140' and the fourth symmetry plane 166'. The third symmetry plane 140' and the fourth symmetry plane 166' are respectively perpendicular to the optical axis 114'.

[0145] The two further correction pair assemblies 138 ″, 168 ″ are arranged and / or formed symmetrically with respect to the first plane of symmetry 120 ″. Furthermore, as described above, the correction pair assemblies 134 ″ are symmetrical with respect to the first plane of symmetry 120 ″. Thus, in this embodiment, the six correction elements 124 ″ are arranged symmetrically with respect to the first plane of symmetry 120 ″.

[0146] Correction pair assembly 134' Fig. 9 1. Each of these correction elements 124' of the correction pair assembly 134' comprises a first lens 130' and a second lens 132'. The first lens 130' and the second lens 132' are integrally formed, for example, by bonding and / or optical bonding. Together they form a lens system 128'.

[0147] The first lens 130' is made of a first lens, while the second lens 132' is formed of a second lens. The first lens and the second lens are selected in such a way that they deviate from the lens with normal dispersion in opposite ways. In this regard, reference is again made to Figure 7 To clarify.

[0148] For example, the Abbe number ν of the first lens d The refractive index is 42.41 and n D is 1.63775 and the dispersion n F -n C For example, the Abbe number ν of the second lens d is 63.33, refractive index n D is 1.61800 and the dispersion n F -n C is 0.009758. Therefore, the two lenses are intentionally selected to be different and intentionally deviate from normal dispersion in opposite ways. Thus, the lens assembly 112' can provide high-quality imaging over a wide spectral range.

[0149] The first lens 130' is a convex lens. The second lens 132' is a concave lens. Exemplarily, the first lens 130' has a curvature radius of 12 mm. In addition, exemplary, the second lens 132' has a curvature radius of -4.8 mm.

[0150] The correction pair 134 ′ has an opening 144 ′ which is arranged in the region of the second plane of symmetry 136 ′. The opening 144 ′ has a smaller diameter than the rod lenses 112 and the correction element 124 .

[0151] In the present embodiment, the correction elements 124' are each formed integrally with the rod lenses 122'. For example, the correction elements are glued and / or optically bonded to an especially flat end face of the associated rod lens 122'.

[0152] On the side opposite to the corresponding correction element 124', a further lens 172' is arranged, which is part of the rod lens 122'. The further lens is glued and / or optically bonded to the base body of the rod lens 122'. In the present case, the base body of the rod lens 122' consists of an Abbe number v d is 50.19 and the refractive index n D The base of the rod lens 122' has a flat end face. The other lens 172' is made of an Abbe number v d The refractive index is 49.34. D is 1.74320 and the dispersion n F -n C The other lens 172' is a concave lens and has a radius of curvature of 13.7 mm, for example.

[0153] Fig.10 A schematic diagram of a third endoscope device 110" according to the present disclosure is shown. In order to be able to distinguish better, the reference numerals of this embodiment are provided with two quotation marks. Unless otherwise specified, the existing components can also refer to the above statements in principle. The third endoscope device 110" can be used in the visible light range and the near infrared range. The third endoscope device 110" includes a lens assembly 112", an eyepiece 116" and an objective lens 118". Here, they are arranged Figure 1 The lens assembly 112" optically couples the eyepiece 116" to the objective lens 118". Therefore, through the lens assembly 112", light can be substantially equivalently transmitted and imaged at least in the range between 480nm and 1000nm, preferably in the range between 400nm and 1000nm.

[0154] The lens assembly 112" includes six rod lenses 122". In addition, the lens assembly 112" includes four correcting elements 124". The lens assembly 112" defines an optical axis 114". The rod lenses 122" and the correcting elements 124" are arranged coaxially with respect to the optical axis 114". In the illustrated case, the rod lenses 122" and the correcting elements 124" each have a circular cross-section, the center of which is located on the optical axis 114".

[0155] The lens assembly 112" is symmetrical about a first symmetry plane 120". The first symmetry plane 120" is perpendicular to the optical axis 114".

[0156] Two of these correction elements 124" are part of a correction pair assembly 134" or constitute the correction pair assembly. The two correction elements 124" of the correction pair assembly 134" are symmetrical to each other about a second symmetry plane 136". The second symmetry plane 136" is different from the first symmetry plane 120". The second symmetry plane 136" is perpendicular to the optical axis 114".

[0157] The other two of these correction elements 124" are part of a further correction pair assembly 138" or constitute the correction pair assembly. The two correction elements 124" of the further correction pair assembly 138" are symmetrical to each other with respect to a third symmetry plane 140". The third symmetry plane 140" is different from the first symmetry plane 120" and from the second symmetry plane 136". The third symmetry plane 140" is perpendicular to the optical axis 114".

[0158] Correction pair component 134 ″ and further correction pair component 138 ″ are arranged and / or formed symmetrically with respect to first plane of symmetry 120 ″. In this embodiment, provision can be made for no correction pair component to be present in the region of first plane of symmetry 120 ″.

[0159] Correction pair assembly 134" Fig.11 . Each of the correction elements 124" of the correction pair assembly 134" includes a first lens 130", a second lens 132" and a third lens 142". These lenses form a lens triplet. The first lens 130", the second lens 132" and the third lens 142" are formed integrally, for example, by bonding and / or optical bonding. Together they form a lens system 128".

[0160] The first lens 130" is made of a first lens, and the second lens 132 is formed of a second lens. The first lens and the second lens are selected in such a way that they deviate from the lens with normal dispersion in opposite ways. In this regard, reference is again made to Figure 7 To clarify.

[0161] For example, the Abbe number ν of the first lens dThe refractive index is 59.71. D is 1.53996 and the dispersion n F -n C For example, the Abbe number ν of the second lens d is 63.33, refractive index n D is 1.61800 and the dispersion n F -n C is 0.009758. Therefore, the two lenses are intentionally selected to be different and intentionally deviate from normal dispersion in opposite ways. As a result, lens assembly 112" can provide high-quality imaging over a wide spectral range.

[0162] In this embodiment, the third lens 142" is made of a third lens different from the first lens and the second lens. For example, the Abbe number v of the third lens is d The refractive index is 47.11, D is 1.67003 and the dispersion n F -n C It is 0.014380.

[0163] The first lens 130" is a convex lens. The second lens 132" is a concave lens. The third lens 142" is a convex lens. Exemplarily, the first lens 130" has a radius of curvature of 8.5 mm. Furthermore, exemplarily, the second lens 132" has a radius of curvature of -7.8 mm. Furthermore, exemplarily, the third lens 142" has a radius of curvature of 82 mm.

[0164] The correction pair assembly 134 ″ has an opening 144 ″, which is arranged in the region of the second plane of symmetry 136 ″. The diameter of the opening 144 ″ is smaller than the rod lens 112 ″ and the correction element 124 ″.

[0165] In the present case, no opening is arranged in the region of the further correction pair component 138 ″. In other embodiments, however, an opening is arranged in the region of the further correction pair component 138 ″ instead of or in addition to the opening 144 ′ of the first correction pair component 134 ″.

[0166] Fig.12 A schematic illustration of line pattern imaging performed by the first endoscope device 110, the second endoscope device 110' or the third endoscope device 110" is shown. Compared with the line pattern imaging performed by the lens assembly according to the prior art, relatively clear line pattern imaging can be achieved in the entire spectral range between 400nm and 100nm. High-quality imaging can be achieved over a wide spectral range by a combination of appropriately selected lenses and the design and arrangement of the correction element or correction pair assembly.

[0167] Fig.13 A graph showing the wavelength dependency of the RMS spot radius of the first endoscope device 110, the second endoscope device 110' or the third endoscope device 110". The diffraction limit is drawn as a dashed line. As can be seen, the RMS spot radius is below the diffraction limit in at least one range between 480nm and 1000nm. At the blue edge of the range from 400nm to 1000nm, the RMS spot radius increases, but is less than 25μm. It can be seen why the same wavelength is obtained for different spectral ranges. Fig.12 High-quality imaging of the line pattern shown in .

[0168] Fig.14 A schematic illustration of a lens assembly 112 is shown having an anti-reflective surface 170. Such an anti-reflective surface 170 may be used in any of the embodiments described above. Fig.15 A schematic diagram illustrating different reflectivity curves is shown. The two dotted lines show a conventional coating optimized to function in the visible light range or slightly beyond the visible light range. Although lower reflectivity can be achieved in the visible light range, reflectivity rises sharply in the red or near infrared range. For multispectral imaging, hyperspectral imaging, combined white light imaging and fluorescence imaging or other imaging that should be able to image in a wide spectral range, such anti-reflective surfaces are only conditionally applicable.

[0169] This can especially be seen from Fig.16 As can be seen in FIG. 1 , a schematic diagram illustrating different transmittance curves is shown. These transmittance curves are calculated for a lens assembly including 30 surfaces as an example. These surfaces are provided with anti-reflection surfaces, which exhibit Fig.15 Due to the large number of surfaces, the losses at each surface accumulate and the transmittance drops rapidly in the red or near-infrared range.

[0170] In contrast, anti-reflective surfaces may be used in the above-described endoscopic devices 110, 110', 110", which are formed by Fig.15 and Fig.16 . It can be seen that here, in the range between 400nm and 1000nm, the reflectivity may be higher than the value of the surface optimized for the visible light range, but is at a lower level over the entire range. Specifically, the reflectivity is at most 1% over the entire range. This results in a transmittance that is also at a higher level over the entire range, at least above 75%.

[0171] As described above, the endoscopic devices 110, 110', 110" have significant advantages, in particular when they are used for imaging in which a wide spectral range or at least a wavelength range distributed over a wide spectral range is observed. It may therefore be convenient to use a preferably multimodal lighting device 150 that can be used in a broadband situation. This is described in detail exemplarily below. However, it should be understood that the endoscopic devices 110, 110', 110" can also be combined with other suitable lighting devices.

[0172] As described above, the lighting device 150 can be multimodal. The lighting device 150 can operate in different lighting modes, in which the lighting device provides light for different imaging modes. Here, the lighting device 150 can operate in three basic modes, namely a multi-spectral mode, a fluorescent mode, and a white light mode. Similarly, the imaging device 152 can operate in different operating modes, specifically also at least in a multi-spectral mode, a fluorescent mode, and a white light mode. In the corresponding operating mode of the imaging device 152, the modes of the lighting device 150 match each other.

[0173] Fig.17 1 shows a schematic diagram of an illumination device 150. The illumination unit 18 comprises a plurality of light emitting elements 20, 22, 24, 26, 28 which can be activated independently of each other. These light emitting elements are configured to emit light according to different emission spectra to provide illumination light, i.e. the respective emission spectra are different between the light emitting elements.

[0174] Exemplarily, the light emitting elements 20, 22, 24, 26, 28 are designed as LEDs. Specifically, the first light emitting element 20 is designed as a red LED, the second light emitting element 22 is a dark red LED, the third light emitting element 24 is a blue LED, and the fourth light emitting element 26 is a near IR-LED. The colored light emitting elements 20, 22, 24, 26 emit light in a narrow band, for example, the light emission peaks are approximately at wavelengths of 660nm (first light emitting element 20), 770nm (second light emitting element 22), 460nm (third light emitting element 24), and 940nm (fourth light emitting element 26).

[0175] Furthermore, a fifth light emitting element 28 is provided, which is a white light emitting element, such as a white light LED. The fifth light emitting element 28 emits light, for example, in a spectral range of about 400 nm to 700 nm. In other embodiments, a laser diode can also be used, in particular as a colored light emitting element.

[0176] Depending on the lighting mode, some of the light emitting elements 20, 22, 24, 26, 28 are at least temporarily enabled, whereas other light emitting elements 20, 28, 24, 26, 22 may not be used in the corresponding lighting mode.

[0177] Here, the first group includes a first light-emitting element 20 and a fourth light-emitting element 26. The first group may also include a light-emitting element 22 and / or a light-emitting element 24. The first group is used for multispectral imaging, in which the light-emitting elements 20, 26 and, if necessary, 22 and 24 are respectively used as supporting points. In multispectral mode, for example, the first light-emitting element 20 is first used to illuminate and capture images. Then, the fourth light-emitting element 26 is used to illuminate and capture images. These images are respectively based on reflection, that is, observing the light reflected back by the object to be imaged. Through these two different supporting points, spectral information about the object to be imaged can be obtained. For example, specific tissue types, perfusion states, tissue structures, etc. can be evaluated in this way.

[0178] In addition, the second group includes a first light-emitting element 20, a second light-emitting element 22 and a third light-emitting element 24. The second group is used for illumination during fluorescence imaging. Here, for example, objects colored with appropriately selected dyes can be observed in a targeted manner. Different dyes can also be introduced into different tissue types or the like that are observed at the same time. By specifically exciting a specific dye, the dye is excited to emit fluorescence. Then the fluorescence is imaged. The first light-emitting element 20 is suitable for exciting cyanine 5.5 (Cy 5.5) dye, for example. The second light-emitting element 22 is suitable for exciting indocyanine green (ICG) dye. The third light-emitting element 24 is suitable for exciting fluorescein dye.

[0179] In addition, the third group includes a fifth light-emitting element 28. In this embodiment, the third group also includes a first light-emitting element 20 and a third light-emitting element 24. The third group is used to provide illumination light for white light imaging. To this end, the white light of the fifth light-emitting element 28 can be mixed with the light of a specific colored light-emitting element, so that spectral loss can be compensated and / or the color temperature can be adjusted in a targeted manner.

[0180] It can be seen that some of the light emitting elements 20, 22, 24, 26, 28 are assigned to multiple groups, exemplarily the first light emitting element 20 is assigned to all three groups, and the third light emitting element 24 and optionally also the second light emitting element 22 are assigned to the second and third groups.

[0181] Alternatively or additionally, it can also be proposed that some or all of the light emitting elements 20, 22, 24, 26, 28 are applied in a hyperspectral mode. Then, a wide excitation spectrum is generated. Thus, in combination with a suitable hyperspectral detector, spectral information about the object to be imaged can be detected over the entire visible light spectrum and the near IR spectrum. For this purpose, the imaging device 14 can include a push-broom assembly as a hyperspectral detector. In other embodiments, a swing-broom assembly, a staring assembly and / or a snapshot assembly are used. The imaging device 14 can be a hyperspectral imaging device. For different approaches to hyperspectral imaging and the components required for this purpose, see the professional article “Review of spectral imaging technology in biomedical engineering: achievements and challenges” by Quingli Li et al., Journal of Biomedical Optics, 18(10), 100901, October 2013, and the professional article “Medical hyperspectral imaging: a review” by Guolan Lu and Baowei Fei, Journal of Biomedical Optics, 19(1), 010901, January 2014.

[0182] The illumination unit 18 comprises two cross beam splitters 30, 32. These cross beam splitters respectively comprise output sides 42, 44, input sides 37, 41 opposite to the output sides 42, 44, and two input sides 34, 36, 38, 40 opposite to each other. All input sides 34, 36, 37, 38, 40, 41 guide incident light to the corresponding output sides 42, 44. The output side 42 of the first cross beam splitter 30 faces the input side 41 of the second cross beam splitter 32. The output side 44 of the second cross beam splitter 32 faces the optical interface 16. The two cross beam splitters 30, 32 are preferably arranged coaxially to each other and / or coaxially to the optical interface.

[0183] The lighting unit 18 may include suitable optical elements, such as lenses and / or reflectors (not shown). Fig.17, a plurality of lenses 78, 80, 82, 84, 86, 88 are shown. For example, lens 78 is assigned to optical interface 16 and couples light from the output side 44 of the second cross beam splitter 32 into optical interface 16. In addition, a lens 80, 88, 84, 86, 82 can be assigned to each of the light-emitting elements 20, 22, 24, 26, 28. A particularly high compactness can be achieved, in particular, when the light-emitting elements 20, 28, 24, 26, 22 are arranged on the input side 34, 40, 37, 38, 36 of the at least one cross beam splitter 30, 32, respectively, without a reflector arranged in between. Thus, the light-emitting elements 20, 22, 24, 26, 28 can be very close to the at least one cross beam splitter 30, 32.

[0184] The cross beam splitters 30, 32 each comprise two beam splitter elements 90, 92, 94, 96. These beam splitter elements can in principle be partially transparent, so that light from all input sides 34, 36, 37, 38, 40, 41 is deflected to the corresponding output side 42, 44. In the present embodiment, the beam splitter elements 90, 92, 94, 96 are selectively light-transmissive. This is further referred to Figure 3 The beam splitter elements 90, 92, 94, 96 may be filters that are reflective only within a limited range and have high transmittance in other ranges. Fig.18 In the figure, the transmission curves 98, 100, 102, 104 of the beam splitter elements 90, 92, 94, 96 of the two cross beam splitters 30, 32 are shown. Each of these colored light-emitting elements 20, 22, 24, 26 or each of these opposite input sides 34, 36, 38, 40 is assigned one of these beam splitter elements 90, 92, 94, 96. Here, the beam splitter elements 90, 92, 94, 96 are selected in such a way that they reflect in the wavelength range in which the assigned light-emitting element 20, 22, 24, 26 emits light, and essentially transmit otherwise. For this purpose, notch filters can be used in the medium wavelength range, which can have transmission spectra 100 and 102 by way of example. At the edges of the spectrum, high-pass or low-pass filters can also be used instead of notch filters, see transmission spectra 98 and 104.

[0185] Due to the specific transmission spectra 98, 100, 102, 104 of the cross beam splitters 30, 32, the light of the fifth light-emitting element 28 is spectrally reduced. Therefore, the light blocked by the beam splitters 30, 32 can be supplemented in the manner already mentioned conveniently with the aid of the light-emitting elements 20 and 24 (and 22 and / or 26 if necessary). Thus, supplementation can be carried out in particular in the following spectral ranges, i.e. in these spectral ranges, the beam splitters 30, 32 absorb and / or reflect the light of the fifth light-emitting element 28, but in any case it is not transmitted to the optical interface 16. Here, the light-emitting elements 20, 24 and, if necessary, 22 used for supplementation are preferably operated at a lower power or at an adapted power. Here, the purpose can be to at least substantially restore the initial spectrum of the fifth light-emitting element 28.

[0186] In some embodiments, the fifth light-emitting element 28 may alternatively be a green light-emitting element, or in general, the fifth light-emitting element is a colored light-emitting element that emits light primarily in the spectral range transmitted by the at least one beam splitter 30, 32. For example, in such an embodiment, the fifth light-emitting element 26 may be an LED with a peak emission at about 530 nm. In this regard, green laser diodes are also considered. It can be pointed out here that in the white light mode, color mixing can be performed, and in particular, instead of using an independent white light source (such as a white light LED), the white light is generated by targeted mixing of individual light-emitting elements.

[0187] It will be appreciated that, given a suitable dye, such a green luminescent element can also be used in a fluorescence mode. Alternatively or additionally, it may be used in a multispectral mode.

[0188] The illumination unit 18 defines a common optical path 54 into which the light emitted by the light emitting elements 20, 22, 24, 26, 28 can be coupled. The common optical path 54 extends from the output side 44 of the second cross beam splitter 32 to the optical interface. Here, the common optical path 54 is arranged coaxially with the fifth light emitting element 26.

[0189] In the illustrated embodiment, the light emitting elements 20, 26 of the first group are arranged such that the light emitted from the light emitting elements 20, 26 travels through optical paths of at least substantially equal distance from the respective light emitting elements 20, 26 until reaching the optical interface 16. The light emitting elements 20, 26 of the first group each have a light emitting surface 56, 58. The light emitting surfaces 56, 62 are arranged equidistantly with respect to the common optical path 54. Here, this is achieved in the following manner: the two light emitting elements 20, 26 are arranged at equal distances from the beam splitter 32 to which they are assigned (here, exemplarily the second beam splitter 32), in particular at equal distances from the opposite input sides 38, 40 of the beam splitter. Here, light is coupled from the cross beam splitter 32 into the common optical path 54.

[0190] The beam splitters 30 , 32 are arranged in particular such that the light-emitting surfaces 56 , 64 , 26 , 28 , 58 of the light-emitting elements 20 , 22 , 24 , 60 , 62 are respectively arranged equidistantly with respect to their assigned cross beam splitters 30 , 32 .

[0191] By using cross beam splitters 30, 32 and light emitting elements 20, 22, 24, 26, 28 that can be used together for different modes, the illumination unit 18 or illumination device 12 is highly compact. Furthermore, the equidistant arrangement makes it possible that when the imaging device 14 or its light guide is rotated relative to the optical interface 16, no spectral shift occurs.

[0192] It should be understood that different numbers of light emitting elements 20, 22, 24, 26, 28 and / or different numbers of cross beam splitters 30, 32 may be used. The use of cross beam splitters 30, 32 has proven to be particularly convenient. However, in other embodiments, other types of beam splitters and / or other optical elements may be used to couple the light of the light emitting elements 20, 22, 24, 26, 28 into the optical interface 16.

[0193] List of Reference Numerals

[0194] 110 Endoscopic device

[0195] 112 Lens Assembly

[0196] 114 Optical Axis

[0197] 116 Eyepiece

[0198] 118 Objective lens

[0199] 120 First symmetry plane

[0200] 122 Rod lens

[0201] 124 Correction element

[0202] 126 Optical System

[0203] 128 Lens System

[0204] 130 First lens

[0205] 132 Second lens

[0206] 134 Calibration Pair Components

[0207] 136 Second symmetry plane

[0208] 138 Calibration Pair Components

[0209] 140 Third symmetry plane

[0210] 142 Third lens

[0211] 144 Orifice

[0212] 146 Endoscope

[0213] 148 Imaging System

[0214] 150 lighting fixtures

[0215] 152 Imaging Device

[0216] 154 Image Detection Unit

[0217] 156 Display

[0218] 158 Image Detection Sensor Device

[0219] 160 Shaft

[0220] 162 Remote

[0221] 164 Proximal

[0222] 166 Fourth symmetry plane

[0223] 168 Calibration Pair Components

[0224] 170 Anti-reflective surface

[0225] 172 Lens

Claims

1. An endoscopic device (110), in particular an endoscopic device for hyperspectral and / or multispectral imaging, the endoscopic device comprising a lens assembly (112), the lens assembly defining an optical axis (114) and being configured to optically couple an eyepiece (116) to an objective lens (118), wherein the lens assembly (112) is configured to achieve substantially equivalent light transmission and imaging for a given focus over a majority of the visible light range and in the near infrared range, wherein the lens assembly (112) is symmetric about a first symmetry plane (120) perpendicular to the optical axis (114), and wherein the lens assembly (112) include: at least six rod lenses (122); At least two correcting elements (124), which together with the rod lens (122) define an optical system (126), and each of the correcting elements includes a lens system (128) having at least a first lens (130) and a second lens (132), wherein the first lens (130) is made of a first lens and the second lens (132) is made of a second lens, wherein the first lens and the second lens have different Abbe numbers, and wherein the relative partial dispersion of the first lens and the relative partial dispersion of the second lens deviate from a lens with normal dispersion in opposite ways; and at least one correcting pair assembly (134), which includes two correcting elements in the correcting element (124), and the two correcting elements are symmetrical to each other about a second symmetry plane (136) perpendicular to the optical axis (114).

2. The endoscopic device (110) according to claim 1, wherein the first plane of symmetry (120) and the second plane of symmetry (136) coincide with each other.

3. An endoscopic device (110) according to claim 1 or 2, wherein the lens assembly (112) includes at least one additional correction pair assembly (138), wherein the additional correction pair assembly (138) includes two additional correction elements in the correction element (124), and the two additional correction elements are symmetrical to each other about a third symmetry plane (140) perpendicular to the optical axis (114).

4. The endoscopic device (110) according to claim 3, wherein the second symmetry plane (136) and the third symmetry plane (140) are different from the first symmetry plane (120).

5. The endoscopic device (110) according to one of the preceding claims, wherein the correction elements (124) each comprise at least a third lens (142), which is made of the first lens.

6. The endoscopic device (110) according to one of the preceding claims, wherein the correction elements (124) are each formed integrally with the rod lenses (122).

7. The endoscopic device (110) according to one of the preceding claims, wherein the calibration pair component (134) comprises at least one opening (144) which is arranged in the region of the second plane of symmetry (136).

8. The endoscopic device (110) according to one of the preceding claims, wherein the second lens (132) is a convex lens.

9. The endoscope device (110) according to any one of claims 1 to 7, wherein the second lens (132) is a concave lens.

10. The endoscopic device (110) according to one of the preceding claims, wherein the lens assembly (112) is capable of optical imaging in the range of 400nm to 1000nm, the optical imaging having an RMS spot radius of at most 40μm, preferably at most 35μm and preferably at most 30μm.

11. The endoscopic device (110) according to any of the preceding claims, wherein the lens assembly (112) is capable of diffraction-limited optical imaging in the range of 480 nm to 1000 nm.

12. The endoscopic device (110) according to one of the preceding claims, wherein the lens assembly (112) has a maximum RMS spot radius of at most 8 μm, preferably at most 6 μm and preferably at most 4 μm.

13. The endoscopic device (110) according to one of the preceding claims, wherein the rod lens (122) and the correction element (124) have antireflection surfaces (164) which are effective in the visible light range and the near infrared range.

14. The endoscopic device (110) according to claim 13, wherein the anti-reflection surfaces (164) each cause an average reflectivity of at most 2%, preferably at most 1% and preferably at most 0.6% in the range of 400 nm to 1000 nm.

15. The endoscopic device (110) according to claim 13 or 14, wherein the anti-reflection surface (164) each causes a maximum reflectivity of at most 3%, preferably at most 2% and preferably at most 1% in the range of 400 nm to 1000 nm.

16. The endoscopic device (110) according to one of the preceding claims, wherein the lens assembly has an average transmission in the range of 400 nm to 1000 nm of at least 70%, preferably at least 80% and particularly preferably at least 85%.

17. The endoscopic device (110) according to one of the preceding claims, wherein the lens assembly has a minimum transmittance in the range of 400 nm to 1000 nm of at least 60%, preferably at least 70% and particularly preferably at least 80%.

18. The endoscopic device (110) according to one of the preceding claims, further comprising the eyepiece (116) and / or the objective lens (118).

19. A correction pair assembly (134) for a lens assembly (112) for an endoscope (146), the correction pair assembly comprising at least two correction elements (124), the correction elements defining an optical axis (114) and being configured to define an optical system (126) together with a plurality of rod lenses (122), and the correction elements each comprising a lens system (128) having at least a first lens (130) and a second lens (132), wherein the first lens (130) is made of a first lens and the second lens (132) is made of a second lens, wherein the first lens and the second lens have different Abbe numbers, and wherein the relative partial dispersions of the first lens and the second lens deviate in opposite ways from a lens having normal dispersion; wherein the correction elements (124) are symmetrical to each other about a symmetry plane (120, 132, 140, 166) perpendicular to the optical axis.

20. The calibration pair assembly (134) according to claim 19, further comprising an orifice (144) which is arranged in the region of the symmetry plane (120).

21. An endoscope (146) having an endoscopic device (110) according to one of claims 1 to 18 and / or a correction pair assembly (134) according to claim 19 or 20.

22. An imaging system (148), the imaging system include: An illumination device (150) configured to provide illumination light in a visible light range and a near infrared range; An endoscopic device (110) according to one of claims 1 to 18 and / or an endoscope (146) according to claim 21; and an imaging device (152), the imaging device having an image detection unit (154), which is configured to detect multispectral and / or hyperspectral image data.

Images