MEDICAL ENDOSCOPE WITH AN IMAGING DEVICE

Description

[0001] The present invention relates to a medical endoscope having an optical imaging device for generating a real image of an object viewed by means of the endoscope.

[0002] In many medical fields, optical inspection of thin-caliber cavities or hollow organs is diagnostically advantageous and desirable. Examples include dental root canals with a typical diameter of 0.5 mm or less, salivary ducts with a typical diameter of 1 mm or less, Eustachian tubes with a typical diameter of 1.5 mm or less, and lactiferous ducts with a typical diameter of 1.3 mm or less. Furthermore, in the future—with appropriate irrigation—optical inspection of the inner walls of blood vessels or lymphatic vessels could be diagnostically advantageous and desirable. In the context of bronchoscopy, optical inspection of alveoli would be diagnostically advantageous and desirable. Optical inspection of an embryo in the womb would also be diagnostically advantageous and desirable. These applications require correspondingly thin optical inspection instruments, particularly endoscopes.

[0003] New manufacturing processes enable ever more precise production of ever smaller structures, even from optically transparent materials.

[0004] EP 1 961 371 B1 describes an illumination device for an image capture device at the distal end of an endoscope. Microlenses are provided for beam shaping (paragraph

[0024] ).

[0005] DE 10 2015 003 652 A1 describes a method for connecting a solid-core optical fiber to another optical fiber and a method for providing a solid-core optical fiber with a joining device for connecting the solid-core optical fiber to another optical fiber (title, paragraphs

[0015] ,

[0016] ). The joining device is applied to the axial end of the solid-core fiber by means of 3D printing based on two-photon polymerization (paragraphs

[0016] ,

[0021] ).

[0006] DE 10 2015 012 980 A1 describes a method and a device for producing microstructures on optical fibers using a 3D printer (title, paragraphs

[0007] ,

[0009] ,

[0058] ,

[0064] ,

[0067] ). Two-photon polymerization can be used (paragraph

[0059] ).

[0007] EP 3 162 549 A1 describes a method and a device for producing an optical element with a diaphragm or a structure for scattered light absorption (title, paragraphs

[0004] ,

[0008] ,

[0012] ). A three-dimensional structure with a microfluidic cavity is formed using a 3D printer. The microfluidic cavity is subsequently filled with a functional substance by capillary action (paragraph

[0015] ).

[0008] DE 10 2015 103 214 A1 describes a trocar 20 intended to enable penetration of the abdominal wall under optical control. For this purpose, the trocar has a cavity in which a shaft of an endoscope can be arranged, and an at least partially optically transparent tip 24. Lenses 30 and prisms 40 are provided between the intended position of the distal end 11 of the endoscope 10 and the transparent tip 24 of the trocar 20 to change the viewing direction from the endoscope viewing direction to a trocar viewing direction and to enable a straight-ahead view in the trocar with a side-view endoscope.

[0009] DE 697 34 638 T2 describes an optical system of an endoscope with a rotationally asymmetric curved surface.

[0010] US 5,912,764 describes an optical system for an endoscope (column 1, lines 5 to 8; column 1, line 66, to column 2, line 1).

[0011] DE 10 2011 089 157 A1 describes a video endoscope with a lateral viewing direction (paragraphs

[0001] ,

[0007] ). The video endoscope 1 comprises a meniscus lens 12 at the distal end of its endoscope shaft 2, a prism 11 that deflects laterally incident light rays in an axial direction, and lenses 23, 23' in front of an optical sensor 21 (paragraph

[0029] , figure).

[0012] WO 2009 / 019703 A2 describes a laryngoscope device (title; abstract; page 1, lines 4, 5). An aperture lens 66 has a proximal concave surface 68 and a distal concave, tilted prism surface 69 (page 6, lines 22 to 24; Figure 5 ).

[0013] EP 0 647 425 A1 describes an endoscope attachment for changing the viewing angle (title; page 2, lines 5, 6). A plano-concave diverging lens 26, 56 is arranged in front of a prism 24, 50, 66 in the direction of light propagation, in which total internal reflection occurs. A plano-convex converging lens 58 is arranged after the prism 24, 50, 66, which is apparently intended to produce a real image.

[0014] EP 2 056 150 A1 describes a transmissive optical element 2 (title, abstract, paragraphs

[0001] ,

[0075] , Figures 1 , 4 , 5 , 8, 9, 10, 13, 16, 19, 22). The transmitting optical element is rotationally symmetrical (paragraphs

[0005] ,

[0006] ,

[0011] ,

[0020] ,

[0021] ,

[0045] , etc.).

[0015] The article "High-Speed ​​3D Printing of Millimeter-Size Customized Aspheric Imaging Lenses with Sub-7 nm Surface Roughness" (Xiangfan Chen et al., Advanced Materials, Volume 30, Issue 18, 2018) describes a method for manufacturing customized optical elements. Using a dynamic mask, an entire two-dimensional layer can be photopolymerized with a single exposure instead of a single voxel.

[0016] US 2005 / 0272979 A1 describes a visual device for an endoscope. The visual device comprises an optical system or an optical system comprising several optical systems and realizes an aperture angle of more than 90 degrees.

[0017] An object of the present invention is to provide an improved endoscope.

[0018] This problem is solved by the subject matter of independent claim 1.

[0019] Further training is specified in the dependent claims.

[0020] An endoscope comprises a shaft having a distal end, an optical imaging device at the distal end of the shaft for generating a real image of an object viewed by means of the endoscope, and at least either an image transmission device for transmitting the real image or an image sensor for capturing the real image, wherein the imaging device has curved light-refracting interfaces that are tilted relative to one another, wherein the viewing direction of the medical endoscope is not parallel to the longitudinal axis of the distal end of the shaft of the medical endoscope, and wherein the imaging device is manufactured by means of 3D printing.

[0021] According to the invention, the endoscope is intended for medical applications, for example, as a sialendoscope for the optical inspection of a salivary duct, as a fetoscope for the optical inspection of an unborn fetus in the amniotic sac, as a cystoscope for cystoscopy, as a root canal endoscope for the optical inspection of the root canal of a tooth in endodontics, or for ductoscopy, i.e., for the optical inspection of a milk duct of a mammary gland. Alternatively, and not covered by the subject matter of the claims, the endoscope can be intended and designed for technical applications.

[0022] The shaft of the endoscope is particularly long and thin. The shaft can be straight or curved, rigid or flexible.

[0023] The image transmission device can, for example, comprise a plurality of sequentially arranged rod lenses or another relay lens system or an ordered bundle of optical fibers. The image transmission device transmits the real image generated by the optical imaging device, in particular to a proximal end of the endoscope. At the proximal end of the endoscope, the transmitted real image can be directly observed through an eyepiece or captured and converted into an image signal by a camera coupled to the eyepiece or by one or more image sensors optically coupled to the endoscope in some other way or integrated into the endoscope. Alternatively, one or more image sensors are arranged directly on the imaging device in order to capture the real image generated by the imaging device and convert it into an analog or digital image signal.

[0024] In particular, the curved refractive interfaces are tilted relative to one another in such a way that there is no common axis of symmetry to which all curved refractive interfaces would be rotationally symmetric. In particular, the surface normals of the curved refractive interfaces at their vertices or at their surface centers are not parallel to one another and / or not parallel to a straight line connecting the vertices or surface centers. Alternatively, for example, the mean surface normals of the curved refractive interfaces may not be parallel to one another and / or not parallel to a straight line connecting the vertices or surface centers of the curved refractive interfaces. This arrangement and orientation of the curved refractive interfaces is also referred to as off-axis.In addition to two or more curved refractive interfaces that are tilted relative to one another, the imaging device can also have one or more further curved refractive interfaces that are arranged parallel to one another or to one of the curved refractive interfaces tilted relative to one another or symmetrically to a common optical axis.

[0025] An imaging device with curved light-refracting interfaces that are tilted against each other enables unusual imaging properties, for example a deviation of the viewing direction from the surface normal of the real image generated by the optical imaging device, a distortion or rectification and / or a non-parallelism of the object surface and the image surface.

[0026] In an endoscope as described here, the diameter of the shaft is in particular not greater than 3 mm or not greater than 1.5 mm or not greater than 1.0 mm or less than 1.0 mm.

[0027] In an endoscope as described here, the diameter of the imaging device is in particular not greater than 3 mm or not greater than 1.5 mm or not greater than 1.0 mm or less than 1.0 mm.

[0028] In an endoscope as described here, in particular one of the curved light-refracting interfaces of the imaging device is not rotationally symmetric.

[0029] A curved refractive interface is not rotationally symmetric if there is no axis of symmetry to which the curved refractive interface would be rotationally symmetric. The imaging device may have multiple curved refractive interfaces, each of which is not rotationally symmetric.

[0030] In an endoscope as described here, in particular one of the curved light-refracting interfaces of the imaging device is not a section of a rotationally symmetric curved surface.

[0031] In particular, several or all curved refractive interfaces of the imaging device are not sections of rotationally symmetric curved surfaces.

[0032] In an endoscope as described here, in particular one of the curved refractive interfaces is a freeform surface.

[0033] In particular, several or all curved refractive interfaces can be freeform surfaces. A freeform surface is, in particular, a surface that is not a section of a spherical surface, an ellipsoid of revolution, or a hyperboloid of revolution. Configuring one or more curved refractive interfaces of the imaging device as free surfaces can enable extensive adaptation of the optical properties of the imaging device to the requirements of the intended application while simultaneously achieving high imaging quality.

[0034] In an endoscope as described here, the viewing direction of the endoscope is not parallel to the longitudinal axis of the distal end of the shaft of the endoscope according to the invention.

[0035] The viewing direction of the endoscope is, in particular, the direction relative to the center of the light entry surface of the endoscope in which an object is located that is imaged in the center of an image captured by the endoscope. Particularly in the case of a distorted image with significantly different image scales at different locations in the image, the viewing direction of the endoscope can be considered to be the direction from the center of the light entry surface of the endoscope to the center point of the area that is sharply imaged by the imaging device and completely transmitted by the image transmission device or captured by the image sensor.

[0036] Endoscopes whose viewing direction is not parallel to the longitudinal axis of the shaft (in the case of a curved or bendable shaft: not parallel to the longitudinal axis of the shaft at its distal end) are often referred to as side-view endoscopes. Curved refractive interfaces that are tilted relative to each other can enable the endoscope to view in a direction deviating from the longitudinal axis of the shaft without requiring reflective surfaces (e.g., on a prism) or an oblique arrangement of the image sensor.

[0037] In an endoscope as described here, the angle between the viewing direction of the endoscope and the longitudinal axis of the distal end of the endoscope is in particular not less than 10 degrees, not less than 20 degrees, or not less than 30 degrees.

[0038] In an endoscope as described here, an angle between the viewing direction of the endoscope and the longitudinal axis of the distal end of the endoscope is in particular 25 degrees or 30 degrees or 45 degrees or 60 degrees or 70 degrees or 90 degrees or 120 degrees.

[0039] In an endoscope as described here, light contributing to the generation of the real image is not reflected.

[0040] In an endoscope as described here, in particular, no reflective surface is provided upstream of the real image generated by the imaging device.

[0041] In an endoscope as described here, the imaging device in particular has no reflective surface.

[0042] Eliminating a reflective surface can reduce the required installation space and simplify precise manufacturing. In particular, there is no need to manufacture and arrange a prism with totally reflective surface areas.

[0043] In an endoscope as described here, the angle of view of the endoscope is in particular not less than 60 degrees or not less than 70 degrees or not less than 80 degrees or not less than 90 degrees or not less than 100 degrees.

[0044] The angle of view of an endoscope is, in particular, the angle measured from the center of the light entry surface of the endoscope between opposing straight or substantially straight edge sections of the surface that is sharply imaged by the imaging device and whose real image is fully transmitted by the image transmission device or fully captured by the image sensor. Alternatively, the angle of view of an endoscope is, in particular, the angle measured from the center of the light entry surface of the endoscope between opposing edge sections of the surface that is sharply imaged by the imaging device and whose real image is fully transmitted by the image transmission device or fully captured by the image sensor.

[0045] Curved refractive interfaces that are tilted against each other can enable a large angle of view and, at the same time, comparatively good image quality, even when the viewing direction is not parallel to the longitudinal axis of the distal end of the endoscope shaft.

[0046] In an endoscope as described herein, the imaging device comprises at least one of plastic or glass or a mixture of plastic and glass or is formed partially or completely from plastic or glass or a mixture of plastic and glass.

[0047] Glass can be embedded in a plastic matrix in the form of nanoparticles or other small particles. Different optical properties, such as opposing dispersion of the glass particles and the plastic, can enable a reduction in chromatic aberration.

[0048] An endoscope as described herein further comprises, in particular, a diaphragm structure for laterally trimming an optical path, wherein the diaphragm structure is at least either manufactured simultaneously with the imaging device or embedded in the imaging device.

[0049] The aperture structure is formed, in particular, from a light-absorbing material. The aperture structure can be arranged at a light-refracting interface (thus laterally delimiting it), between two light-refracting interfaces, or, with respect to the propagation direction of light emanating from a viewed object, in front of or behind all light-refracting interfaces of the imaging device. The aperture structure can be formed, for example, by means of 3D printing or by filling a cavity in a transparent body of the imaging device through capillary force.

[0050] In an endoscope as described here, the imaging device is manufactured in particular by means of 3D printing based on multi-photon absorption (in particular two-photon absorption) or multi-photon polymerization (in particular two-photon polymerization).

[0051] In an endoscope as described here, the imaging device is produced according to the invention by means of 3D printing, wherein the imaging device is printed directly onto a distal light entry surface of an image transmission device for transmitting the real image or onto a light entry surface of an image sensor for capturing the real image.

[0052] In an endoscope as described here, the imaging device is manufactured from several different materials, in particular by means of 3D printing.

[0053] The imaging device is, in particular, formed from several different materials with different refractive indices. The imaging device is, in particular, made from several different liquid photoreactive or photocuring precursor materials.

[0054] In an endoscope as described here, the imaging device has in particular an interface designed as a diffractive optical element or another diffractive optical element.

[0055] The diffractive optical element can in particular enable chromatic correction by having a dispersion opposite to that of the optically transparent material of the imaging device.

[0056] In an endoscope as described here, the imaging device comprises in particular a plurality of optically transparent bodies with the light-refracting boundary surfaces, which, when used as intended, are penetrated by light emanating from an object being viewed and contributing to the generation of the real image.

[0057] In an endoscope as described here, the imaging device comprises in particular a plurality of optically transparent bodies which, in the intended use, are penetrated by light emanating from an object being viewed and contributing to the generation of the real image, and which have the light-refracting boundary surfaces, wherein a support device mechanically rigidly connects the bodies.

[0058] The plurality of optically transparent bodies are in particular arranged in such a way that light emanating from an object being viewed and contributing to the generation of the real image passes through the transparent bodies one after the other.

[0059] The support device or support structure comprises, for example, one or more support struts. The support device or support structure is particularly connected to edge regions of the bodies with the light-refracting interfaces. The support device can have several, optionally parallel, support struts and / or a network or grid of support struts.

[0060] In an endoscope as described here, the support means and the transparent bodies through which the light passes and which have curved light-refracting interfaces are in particular at least either formed from the same material or manufactured simultaneously.

[0061] Simultaneous manufacture of the support device and the bodies through which the light passes and which have the curved refractive interfaces can enable a precise relative arrangement of the curved refractive interfaces, thus making adjustment obsolete and significantly reducing manufacturing costs.

[0062] According to the invention, an endoscope as described here further comprises, in particular, a light-guiding device at the distal end of the endoscope for directing illuminating light emerging from a distal light exit surface of a light guide or from a light exit surface of a light source, wherein the light-guiding device has a light-refracting interface that is tilted relative to the longitudinal axis of the distal end of the light guide or relative to a surface normal of the light exit surface of the light source. The endoscope comprises, in particular, a light guide in the form of one or more optical fibers for transmitting illuminating light to the distal end of the endoscope. The light-guiding device can be printed directly onto a light exit surface of the light guide or the light source.

[0063] The light-guiding device can have a plurality of refractive interfaces through which, during the intended use, illuminating light passes, subsequently illuminating objects within the field of view. The refractive interfaces of the light-guiding device are arranged, in particular, such that illuminating light passes through the refractive interfaces one after the other. The refractive interfaces are therefore arranged one behind the other, not side by side, in particular with respect to the direction of propagation of the illuminating light.

[0064] A light-refracting interface of the light-guiding device is tilted in particular with respect to the longitudinal axis of the distal end of the light guide or with respect to the surface normal of the light exit surface of the light source in that the mean surface normal or the surface normal at the surface center of the light-refracting interface is not parallel to the longitudinal axis of the distal end of the light guide or to the surface normal of the light exit surface of the light source.

[0065] The tilted arrangement of one or more light-refracting interfaces of the light-guiding device can replace or make obsolete a bending of the distal end of the light guide or a tilting of the light source.

[0066] In an endoscope as described here, the light-refracting interface of the light-guiding device is, in particular, not rotationally symmetrical.

[0067] In an endoscope as described here, the light-refracting interface of the light-guiding device is in particular not a section of a rotationally symmetric curved surface.

[0068] An endoscope as described here further comprises, in particular, a support frame which rigidly connects the imaging device and the light-guiding device to one another.

[0069] In an endoscope as described here, the imaging device and the light-guiding device are in particular at least either mechanically rigidly connected to one another or comprise the same optically transparent material or are monolithically formed according to the invention or are manufactured simultaneously.

[0070] In particular, simultaneous production (e.g. within the same 3D printing process) from the same optically transparent material can enable precise yet cost-effective manufacturing.

[0071] In an endoscope as described here, the light-guiding device has in particular a recess for receiving the distal end of a light guide, wherein the recess defines the position and orientation of the distal end of the light guide.

[0072] The recess is open, in particular, proximally. The recess has the shape of a blind hole, the end of which defines the position of the light exit surface of the light guide. The shape of the recess is selected, in particular, so that the light guide is held in a form-fitting manner in the lateral direction and with minimal play.

[0073] A method, which is not the subject of the claims, for producing an imaging device for an endoscope comprises in particular a step of producing the imaging device by means of 3D printing.

[0074] A method, which is not the subject of the claims, for producing an imaging device for an endoscope comprises in particular a step of producing a mold for the imaging device and a step of producing the imaging device by casting the mold, wherein the mold is produced by means of 3D printing.

[0075] The methods described here, which are not the subject of the claims, for producing an imaging device are particularly suitable for producing an imaging device for an endoscope and can be part of a method for producing an endoscope. Short description of the characters

[0076] The following embodiments are explained in more detail with reference to the attached figures. They show: Figure 1 shows a schematic representation of an endoscope; Figure 2 shows a schematic representation of a distal end of an endoscope; Figure 3 shows a schematic representation of a distal end of another endoscope; Figure 4 shows a schematic representation of a distal end of another endoscope; Figure 5 shows a schematic axonometric representation of an imaging device; Figure 6 shows a schematic flow diagram of a method for producing an imaging device. Description of the embodiments

[0077] Figure 1 shows a schematic representation of an endoscope 10 with a proximal end 11 and a distal end 12. The endoscope 10 has a Figure 1 a direction of view 18 indicated by an arrow and a field of view or field of vision whose edges are indicated by dashed lines.

[0078] The endoscope 10 has a long and thin shaft 20 with a proximal end 21 near the proximal end 11 of the endoscope. Figure 1 In the example shown, the cross section of the shaft 20 is constant or essentially constant over the entire length of the shaft 20. Deviating from the illustration in Figure 1 The cross-section of the shaft may vary. A distal end 22 of the shaft 20 forms the distal end 12 of the endoscope 10. In the example shown, the viewing direction 18 of the endoscope 10 is not parallel to the longitudinal axis of the shaft 20 near its distal end 22.

[0079] In the illustrated example, the shaft 20 is flexible. The endoscope 10 is, for example, a sialendoscope for the optical inspection of a salivary duct, a fetoscope for the optical inspection of a fetus in the mother's amniotic sac, or a cystoscope for cystoscopy. Alternatively, the endoscope 10 can be intended and configured, for example, for the optical inspection of a tooth root canal in endodontics or for ductoscopy, i.e., for the optical inspection of a mammary gland's milk duct.

[0080] The endoscope 10 has an optical imaging device at its distal end 12 for generating a real image. The endoscope 10 can further have one or more image sensors at its distal end 12 for capturing the real image generated by the imaging device. Alternatively, the endoscope 10 can have an image transmission device for forwarding the real image generated by the imaging device to the proximal end 11 of the endoscope. In this case, the real image forwarded to the proximal end 11 can be viewed through an eyepiece, as shown in Figure 1 indicated, viewed and / or captured by one or more image sensors that generate an image signal. One or more image sensors can be integrated into the endoscope 10 near its proximal end 11 or be part of a camera that can be optically and mechanically coupled to the eyepiece of the endoscope.

[0081] Figure 2shows a schematic representation of a section through a distal end 12 of an endoscope, which may be similar in some features, properties and functions to the endoscope shown in Figure 1. The cutting plane of the Figure 2 includes a longitudinal axis 28 of the distal end 22 of the shaft 20, which Figure 2 as the axis of symmetry of the outer surface of a casing component 24 of the shaft 20. Cut surfaces of optically non-transparent components are shown in Figure 2 shown hatched. Cut surfaces of optically transparent components are shown in Figure 2 shown without hatching.

[0082] The viewing direction 18 of the endoscope 10 forms an angle α (alpha) with the longitudinal axis 28 of the shaft 20 and its parallel 28'. The field of view of the endoscope encompasses an angle β (beta).

[0083] At the distal end 22 of the shaft 20, an opening 25 is provided in the optically non-transparent sheath component 24. A first optically transparent body 32 closes the opening 25 in the sheath component 24, in particular in a fluid-tight or hermetically sealed manner. A light entry surface 31 of the first transparent body 32 forms a light entry surface of the endoscope. Figure 2 In the example shown, the light entry surface 31 of the first transparent body 32 is arranged flush with the outer surface of the casing component 24 of the shaft 20. The first transparent body 32 has a light exit surface 33. In the example shown, both the light entry surface 31 and the light exit surface 33 of the first transparent body 32 are curved.

[0084] At the distal end 22 of the shaft 20 and within the casing component 24, a second optically transparent body 35 with a light entry surface 34 and a light exit surface 36 is also arranged. The second transparent body 35 can be printed directly on the image sensor 60 or produced in another way directly on the light entry surface 63 of the image sensor 60 and thereby be integrally connected to it. Alternatively, the second transparent body 35 can initially be manufactured separately, after which its light exit surface 36 is joined to a light entry surface 63 of the image sensor 60.

[0085] The second transparent body 35 can be as in Figure 2 As indicated, they have a recess into which the image sensor 60 is inserted. A positive fit between the recess and the image sensor 60 can enable precise alignment of the image sensor 60 relative to the second transparent body 35, even if they are initially manufactured separately.

[0086] Several support struts 39 mechanically rigidly connect the first transparent body 32 and the second transparent body 35. The ends of the support struts 39 are connected to edge regions of the first transparent body 32 and the second transparent body 35. In the example shown, the support struts 39 are located outside the Figure 2 shown section plane. Therefore, the contours of the support struts 39 are indicated in dotted lines.

[0087] The transparent bodies 32, 35 and the support struts 39 are formed, in particular, simultaneously and from the same optically transparent material. The optically transparent bodies 32, 35 and optionally also the support struts 39 are formed, in particular, by means of a 3D printing process based on multiphoton absorption (in particular, two-photon absorption). Alternatively, and deviating from the subject matter of the claims, one of the transparent bodies 32, 35 or both transparent bodies 32, 35 can be produced by casting a mold, wherein the mold is produced, in particular, by 3D printing, which can be based on multiphoton absorption (in particular, two-photon absorption).

[0088] Alternatively, the transparent bodies 32, 35 can be formed from different materials. Each of the two transparent bodies 32, 35 can alternatively be formed from several sub-bodies made of different materials, for example, to reduce chromatic aberration.

[0089] Near the distal end 22 of the shaft 20, an image sensor 60 is also arranged within the casing component 24. A light entry surface 63 of the image sensor 60 lies flat against the flat light exit surface 36 of the second transparent body 35 and is connected thereto, in particular by a material fit. The image sensor 60 has a plurality of small light-sensitive areas, referred to as image points or pixels, in an arrangement, for example, in the form of a matrix. These image points or pixels are arranged in a thin layer near the light entry surface 63 of the image sensor 60. For simplicity, it is assumed here that the image points or pixels are arranged directly on the light entry surface 63 of the image sensor 60.

[0090] An image generated in the matrix-like arrangement of image points or pixels is captured by the image sensor 60. The image sensor 60 generates an analog or digital, and in particular electrical, image signal representing the captured image.

[0091] Light emanating from an object outside the endoscope can enter the distal end 12 of the endoscope through the light entrance surface 31 of the first transparent body 32, exit the first transparent body 32 through the light exit surface 33 of the first transparent body 32, enter the second transparent body 35 through the light entrance surface 34, exit the second transparent body 35 through the light exit surface 36, and simultaneously enter the image sensor 60 through the light entrance surface 63. The light entrance surface 31 and the light exit surface 33 of the first transparent body 32 and the light entrance surface 34 of the second transparent body 35 are each curved. Figure 2 In particular, the light exit surface 33 of the first transparent body 32 and the light entry surface 34 of the second transparent body 35 are each indicated as being aspherically (ie non-spherically) curved.

[0092] The first transparent body 32 has a refractive index that differs from the refractive index of the medium (in particular air or carbon dioxide or another gas or water or an aqueous solution) in which the distal end 22 of the shaft 20 is located during the intended use of the endoscope. Therefore, the light entry surface 31 of the first transparent body 32 is a light-refracting interface. Between the transparent bodies 32, 35 there is a medium (for example, air or nitrogen) whose refractive index differs from the refractive indices of the materials of the transparent bodies 32, 35. Therefore, the light exit surface 33 of the first transparent body 32 and the light entry surface 34 of the second transparent body 35 are also light-refracting interfaces.

[0093] If the refractive indices of the materials of the second transparent body 35 and the image sensor 60 differ, the interface formed by the light exit surface 36 of the second transparent body 35 and the light entry surface 63 of the image sensor 60 is also light-refracting. However, the light-refracting property of this interface 36, 63 between the second transparent body 35 and the image sensor 60 only plays a role to the extent that the light-sensitive areas of the image sensor 60, referred to as image points or pixels, which are used to generate an image signal, are spaced from the light entry surface 63 of the image sensor 60. As mentioned, it is assumed here for the sake of simplicity that these light-sensitive areas of the image sensor 60 are thin and arranged directly on the light entry surface 63 of the image sensor 60.

[0094] Each of the light-refracting interfaces 31, 33, 34 is curved. Each of the light-refracting interfaces 31, 33, 34 is in particular aspherically curved. This is Figure 2 This is clearly indicated in particular at the light exit surface 33 of the first transparent body 32. Each of the light-refracting boundary surfaces 31, 33, 34 is also not rotationally symmetrical. This is evident in the illustration in Figure 2 This is clearly indicated, in particular, at the light-refracting interfaces 33, 34. Furthermore, each of the light-refracting interfaces 31, 33, 34 is not a section of a rotationally symmetric surface. Each of the light-refracting interfaces 31, 33, 34 is, in particular, designed as a freeform surface and can be described, for example, at least piecewise by one or more polynomial functions.

[0095] At least part of the light-refracting interfaces 31, 33, 34 (in which Figure 2illustrated example: all light-refracting interfaces 31, 33, 34) are tilted relative to one another and / or relative to the longitudinal axis 28 of the distal end 22 of the shaft 20 and the surface normal of the light entry surface 63 of the image sensor 60. This means in particular that the surface normals of the light-refracting interfaces 31, 33, 34 at their surface centers or at their vertices or at their points of maximum curvature or the surface normals of the light-refracting interfaces averaged over the interfaces are not parallel to one another and / or not parallel to the longitudinal axis 28 of the shaft 20 or to the surface normal of the light entry surface 63 of the image sensor 60.

[0096] Light emanating from objects outside the distal end 22 of the shaft 20 can enter the shaft 20 through the light entry surface 31 and be refracted by the light entry surface 31 and the further light-refracting boundary surfaces 33, 34. The first transparent body 32 and the second transparent body 35 form an optical imaging device that generates a sharp image of objects within a designated object area in the image points or pixels of the image sensor 60 at its light entry surface 63. This is shown in Figure 2 indicated by dashed lines.

[0097] In the example shown, the curved, at least partially neither spherically nor otherwise rotationally symmetrically curved and tilted relative to one another light-refracting boundary surfaces 31, 33, 34 have the effect that the viewing direction 18 is not parallel to the longitudinal axis 28 of the shaft 20 at its distal end 22 and not parallel to the surface normal of the light entry surface 63 of the image sensor 60, that the predetermined object surface which is sharply imaged is flat or substantially flat, and that the predetermined object surface which is sharply imaged is orthogonal or substantially orthogonal to the longitudinal axis 28 of the shaft 20 at its distal end 22.Furthermore, the at least partially aspherical and non-rotationally symmetrical design and the mutually tilted arrangement of the light-refracting boundary surfaces 31, 33, 34 can cause a distortion of the generated image, i.e. a variation of the image scale within the image and depending on the direction.

[0098] Figure 3 shows a schematic representation of a section through the distal end 12 of another endoscope, which in some features, properties and functions corresponds to the one shown in the Figures 1 and 2 The type of representation, especially the position and orientation of the cutting plane, corresponds to that of the Figure 2 . In the following, features, properties and functions are described in particular in which the endoscope, the distal end 12 of which is Figure 3 shown, differs from the ones based on the Figures 1 and 2 shown endoscopes.

[0099] The endoscope, whose distal end is Figure 3 is different from that shown in the Figure 2 The endoscope shown in FIG. 1 is distinguished in particular by the fact that no image sensor is provided at the distal end 22 of the shaft 20. Instead, the endoscope has an image transmission device 70 which is Figure 3 is exemplified as an ordered bundle of optical fibers.

[0100] A light entry surface 73 of the image transmission device 70 lies flat against the light exit surface 36 of the second transparent body 35 and can be joined to it flatly, for example, by gluing or welding. Alternatively, the second transparent body 35 can be manufactured directly at the distal end of the image transmission device 70, for example, by 3D printing, and thereby be integrally connected to the light entry surface 73 of the image transmission device 70.

[0101] Figure 4shows a schematic representation of a section through a distal end 12 of another endoscope, which in some features, properties and functions corresponds to the one shown in the Figures 1 to 3 Endoscopes shown, especially the one based on the Figure 2 The type of representation, especially the position and orientation of the cutting plane, corresponds to that of the Figures 2 and 3 . In particular, features, properties and functions of the endoscope, the distal end 12 of which is shown in Figure 4, are described below, in which it differs from the Figures 1 to 3 shown endoscopes.

[0102] The endoscope, whose distal end is 12 in Figure 4, has a light guide 14 that extends in the shaft 20 of the endoscope from its proximal end to its distal end 12. The distal end 15 of the light guide 14 is arranged in a bore 51 of a first transparent body 52 of a light-guiding device. In addition to the first transparent body 52, the light-guiding device comprises a second transparent body 55 that closes a second opening 26 in the casing component 24 in a fluid-tight or hermetically sealed manner.

[0103] The first transparent body 52 of the light-guiding device has a curved light exit surface 53, which is arranged on a side of the first transparent body 52 of the light-guiding device facing away from the recess 51. The recess 51 positively defines the position and orientation of the distal end 15 of the light guide 14 and thus also of a light exit surface 16 of the light guide 14 relative to the light exit surface 53 of the first transparent body 52 of the light-guiding device. The distal end 15 of the light guide 14 is firmly secured in the recess 51 of the first transparent body 52 of the light-guiding device, for example by adhesive bonding or welding.

[0104] The second transparent body 55 of the light-guiding device has a light entry surface 54 facing the light exit surface 53 of the first transparent body 52 and a light exit surface 56 on a side facing away from the light entry surface 54. The light exit surface 56 of the second transparent body 55 is part of the outer surface of the distal end 22 of the shaft 20 of the endoscope. In the example shown, the light exit surface 56 of the second transparent body 55 of the light-guiding device is arranged flush with surrounding areas of the outer surface of the casing component 24.

[0105] The first transparent body 52 and the second transparent body 55 of the light-guiding device can be made of the same or different materials with different refractive indices. The refractive indices of the materials of the transparent bodies 52, 55 of the light-guiding device differ from the refractive index of the gas (e.g., air or nitrogen) in the space between the transparent bodies 52, 55 in the second opening 26 in the cladding component 24. Therefore, the light exit surface 53 of the first transparent body and the light entry surface 54 of the second transparent body 55 of the light-guiding device are light-refracting interfaces.The second transparent body 55 of the light-guiding device has a refractive index that differs from the refractive index of the medium (in particular, air or carbon dioxide or another gas or water or an aqueous solution) in which the distal end 22 of the shaft 20 is located during the intended use of the endoscope. Therefore, the light exit surface 56 of the second transparent body 55 of the light-guiding device is also a light-refracting interface.

[0106] In the illustrated example, the light entry surface 54 of the second transparent body 55 of the light-guiding device is curved, and the light exit surface 56 of the second transparent body 55 is flat. In particular, at least one of the light-refracting boundary surfaces 53, 54, 56 is aspherical, non-rotationally symmetric, or not a section of a rotationally symmetric surface.

[0107] In the example shown, the light-refracting interfaces 53, 54, 56 are further tilted relative to one another in the sense described above for the light-refracting interfaces 31, 33, 34 of the optical imaging device 32, 35.

[0108] The transparent bodies 52, 55 of the light-guiding device, with their curved and mutually tilted light-refracting interfaces 53, 54, 56, control the distribution of illuminating light that is transmitted from the light guide 14 to the distal end 12 of the endoscope, where it passes through the transparent bodies 52, 55 of the light-guiding device and exits the distal end 22 of the shaft 20. The distribution of the illuminating light is particularly adapted to the field of view of the endoscope.

[0109] The luminous flux emanating from the distal end 15 of the light guide 14 and the boundaries of the illuminated area are in Figure 4 indicated by dotted thin lines.

[0110] The light guide 14 can transmit illumination light generated by a light source in the proximal end of the endoscope or transmitted by means of a light guide cable from an external light source to the proximal end of the endoscope to the distal end 12 of the endoscope. Alternatively, the light guide 14 can transmit illumination light generated by a light source in the shaft 20 near its distal end to the light directing device 52, 55. Alternatively, and deviating from the illustration in Figure 4 Instead of the light guide 14, a light source can be provided which is arranged directly on the light-guiding device 52, 55, for example in the recess 51 or on a light entry surface of the first transparent body 52 of the light-guiding device.

[0111] In the Figure 4In the example shown, the endoscope has an image sensor 60 within the sheath component 24 near the distal end 22 of the shaft 20, similar to the one shown in FIG. Figure 2 Alternatively, instead of the image sensor 60, an image transmission device can be provided, for example an ordered bundle of optical fibers as shown in the Figure 3 is shown.

[0112] Figure 5 shows a schematic axonometric representation of an optical imaging device 30 and an image sensor 60, which in some features, properties and functions are similar to the imaging devices of the Figures 2 to 4 The imaging device 30 is shown partially cut away, so that contours of cutting planes along two orthogonal half-planes are visible. The image sensor 60 is shown simply axonometrically without a section and, for simplification, as a cuboid.

[0113] As with the Figures 2 to 4 In the examples shown, curved and tilted light entry surfaces and light exit surfaces 31, 33, 34 of two transparent bodies 32, 35 form light-refracting interfaces with an imaging effect. A light exit surface 36 of the second transparent body 35 is joined to a light entry surface 63 of the image sensor 60. The curvature of the light-refracting interfaces 31, 33, 34 and their tilted arrangement relative to one another and relative to the light entry surface 63 of the image sensor 60 create a viewing direction that is not orthogonal to the light entry surface 63 of the image sensor 60.

[0114] A diffractive optical element 40 consisting of a plurality of annular (but not necessarily circular) steps is provided on the light entrance surface 31 of the first transparent body 32. The diffractive optical element 40 exhibits anomalous dispersion and can thus correct or reduce the chromatic aberration of the optical imaging device 30.

[0115] Deviating from the representation in Figure 5 Alternatively or in addition to the diffractive element 40 on the light entry surface 31 of the first transparent body 32, a diffractive optical element can be provided on the light exit surface 33 of the first transparent body 32 or on the light entry surface 34 of the second transparent body 35 of the optical imaging device 30.

[0116] The first body 32 and the second body 35 of the optical imaging device 30 are mechanically rigidly connected by a plurality of parallel support struts 39, which form a cage shape with the transparent bodies 32, 35. The transparent bodies 32, 35 and the support struts 39 can be formed from the same material or, in particular, can be produced during the same manufacturing step—for example, by 3D printing.

[0117] Figure 6 shows a schematic flow diagram of a method, which is not the subject of the claims, for producing an imaging device for an endoscope. The method is particularly suitable for producing an imaging device with the Figures 2 to 5 properties shown and / or for an endoscope as described in the Figures 1 to 4However, the method is also suitable for producing an imaging device having features, properties and functions that differ from those described in the Figures 1 to 5 The following are examples of reference symbols from the Figures 1 to 5 used to simplify understanding.

[0118] In a first step 101, a mold is produced using 3D printing. In a second step 102, an imaging device is produced by casting the mold. The mold can be designed as a lost mold, which must be destroyed after casting to fully expose the imaging device as a cast part. Alternatively, the mold can be reusable. Reference symbol

[0119] 10 endoscope11Proximal end of the endoscope 10 12Distal end of the endoscope 10 14Light guide for transmitting illumination light 15Distal end of the light guide 14 16Light exit surface of the light guide 14 18Viewing direction of the endoscope 10 20 shaft of the endoscope 10 21 proximal end of the shaft 20 22 distal end of the shaft 20 24 sheath component of the shaft 20 25 first opening in the sheath component 24, for receiving the first transparent body 32 of the optical imaging device 30 26 second opening in the sheath component 24, for receiving the first transparent body 52 of a light-guiding device 28 longitudinal axis of the shaft 20 or the distal end 23 of the shaft 20 28 parallel to the longitudinal axis 28 30 optical imaging device at the distal end 23 of the shaft 20 31 light entry surface of the first transparent body 32, the optical imaging device 30 and the endoscope 10 32 first transparent bodyof the optical imaging device 30 33Light exit surface of the first transparent body 32 of the optical imaging device 30 34Light entry surface of the second transparent body 35 of the optical imaging device 30 35 second transparent body of the optical imaging device 30 36Light exit surface of the second transparent body 35 of the optical imaging device 30 39Support strut for the rigid mechanical connection of the first transparent body 32 and the second transparent body 35 of the optical imaging device 30 40Step-shaped structure on the light entry surface 31 of the first transparent body 32 as a diffractive optical element 51Recess in the first transparent body 52 of a light-guiding device for receiving the distal end of the light guide 15 52 first transparent bodythe light-guiding device 53Light exit surface of the first transparent body 52 of the light-guiding device 54Light entry surface of the second transparent body 55 of the light-guiding device 55 second transparent body the light-guiding device 56Light exit surface of the second transparent body 55 of the light-guiding device 60Image sensor 63Light entry surface of the image sensor 60 70Image transmission device 73Light entry surface of the image transmission device 70 101First step (manufacturing a mold using 3D printing) 102Second step (manufacturing an imaging device by casting the mold)

Claims

1. A medical endoscope< / b> (10), comprising: a shaft (20) comprising a distal end (23); an optical imaging means (30) at the distal end (23) of the shaft (20) configured for producing a real image of an object observed by means of the medical endoscope (10); at least one of an image transmission means (70) configured for transmitting the real image and an image sensor (60) for capturing the real image, wherein the imaging means (30) has curved light-refracting interfaces (31, 33, 34), which are tilted relative to one another, wherein the viewing direction (18) of the endoscope (10) is not parallel to the longitudinal axis (28) of the distal end (22) of the shaft (20) of the medical endoscope (10), characterized in that the imaging means (30) is produced by means of 3D printing, and by a light-steering means (52, 55) at the distal end (22) of the medical endoscope (20) configured for steering illumination light emanating from a distal light-exit surface (16) of a light guide (14) or from a light-exit surface of a light source, and in that the light-steering means (52, 55) has a light-refracting interface (53, 54, 56) tilted relative to a longitudinal axis of the distal end (15) of the light guide (14) or relative to a surface normal of the light-exit surface of the light source, and in that the imaging means (30) and the light steering means (52, 55) are embodied monolithically.

2. Medical endoscope (10) according to one of the preceding claims, wherein one of the curved light-refracting interfaces (31, 33, 34) of the imaging means (30) is not a part of a rotationally symmetric curved surface.

3. Medical endoscope (10) according to one of the preceding claims, wherein the medical endoscope (10) has no reflecting interface upstream of the real image produced by the imaging means.

4. Medical endoscope (10) according to one of the preceding claims, further comprising: an aperture structure for laterally trimming an optical path, wherein the aperture structure is at least one of manufactured simultaneously with the imaging means (30) and embedded in the imaging means (30).

5. Medical endoscope (10) according to one of the preceding claims, wherein the imaging means (30) is produced by means of 3D printing based on multi-photon absorption or multi-photon polymerization..

6. Medical endoscope (10) according to one of the preceding claims, wherein the imaging means (30) is printed directly on a distal light entrance surface (73) of an image transmission means (70) for transmitting the real image or on a light-entrance surface (63) of an image sensor (60) for capturing the real image.

7. Medical endoscope (10) according to one of the preceding claims, wherein the imaging means (30) is produced from a plurality of different materials by means of 3D printing.

8. Medical endoscope (10) according to one of the preceding claims, wherein the imaging means (30) comprises an interface (31) embodied as a diffractive optical element (40) or an other diffractive optical element.

9. Medical endoscope (10) according to one of the preceding claims, wherein the imaging means (30) in particular comprises a plurality of optically transparent bodies (32, 35) providing the light-refracting interfaces (31, 33, 34, 36) and, in the intended use, penetrated by light emanating from an observed object and contributing to the production of the real image, a supporting means (39) mechanically rigidly connects the bodies (32, 35), the supporting means (39) and the transparent bodies (32, 35) are at least one of formed by the same material and produced at the same time.

10. Medical endoscope (10) according to one of the preceding claims, further comprising: a support frame (39) rigidly connecting the imaging means (30) and the light-steering means (52, 55) to one another.

11. Medical endoscope (10) according to one of the preceding claims, wherein the light-steering means (52, 55) has a cutout (51) for receiving the distal end (15) of the light guide (14), the cutout (51) defines the position and the orientation of the distal end (15) of the light guide (14).

12. Medical endoscope (10) according to one of the preceding claims, wherein the light-refracting interface (53, 54, 56) of the light steering means (52, 55) is not rotationally symmetric.