Endoscope, methods for operating an endoscope, and methods for manufacturing an endoscope

Abstract

Endoscope, in particular mediastinoscope (1), with a long shaft (10) and a head (30) arranged at a proximal end section (11) of the shaft (10), wherein a heat source is arranged in the head (30), wherein at least one heat tube (40, 40') extends within the shaft (10), wherein a proximal end section of the at least one heat tube (40, 40') is thermally coupled to the heat source, and wherein the endoscope has an optical system which is closed by a cover glass (27) arranged in a distal end section (14) of the shaft (10), wherein the heat source is a light source (32) for generating illumination radiation, the at least one heat tube (40, 40') extends distally into the distal end section (14) of the shaft (10), and at least one distal end section of the heat tube (40, 40') is thermally coupled to the distal end section (14) of the shaft (10), characterized in thatthat the at least one heat pipe (40, 40') is inserted into a blind hole (45, 45') of the shaft (10) extending in the longitudinal direction of the shaft (10), that the blind hole (45, 45') is connected near its distal end by a transverse hole (46, 46') to another longitudinal hole (18) of the shaft (10), and that the at least one heat pipe (40, 40') is embedded in the blind hole (45, 45') in thermally conductive adhesive (47, 47').

Description

The present invention relates to an endoscope, in particular a mediastinoscope, as well as a method for operating an endoscope and a method for manufacturing a corresponding endoscope. Endoscopes for medical or technical applications have an elongated shaft designed for insertion into a cavity. This shaft contains optical and / or electronic components for capturing an image of a scene within the cavity and transmitting the captured image to a display or viewing device located outside the cavity. To adequately illuminate the endoscopic scene being captured, it is known to transmit illumination generated by an external lighting device to the endoscope via a fiber optic cable, or to arrange one or more light sources, such as light-emitting diodes (LEDs), within the endoscope. However, this generates heat during operation, leading to warming of the endoscope.Furthermore, an endoscope may have additional heat sources, such as an electronic image sensor for capturing an endoscopic image and electronic circuits for evaluating the generated image data. Such heat sources can be located at the distal (i.e., furthest from the user) or proximal (i.e., closer to the user) end of the endoscope, or even in a handle, causing a temperature increase there. However, excessive heating of even partial areas of the endoscope's surface is generally undesirable, especially for endoscopes used in medical applications. For example, heating the shaft surface above 41°C can damage body tissue with which the endoscope comes into contact. Similarly, excessive heating of the handle can impair the operation of the endoscope. It is therefore desirable to dissipate or distribute the heat generated by the heat sources. German patent DE 10 2007 032 200 A1 discloses an endoscope comprising a handle and a probe section connectable thereto, wherein a lighting system with at least one light-emitting diode is arranged in the handle. A support element made of thermally conductive material is provided within the handle for the at least one light-emitting diode, to which the light-emitting diode is directly connected and which can be in thermal contact with housing parts and / or components of the handle and the probe section. According to EP 2 394 567 A1, an endoscope has a long shaft, a headpiece at a proximal end of the shaft, a light source located in a distal region of the shaft which generates heat loss, and passive cooling. The passive cooling system includes a heat pipe located in the shaft, which is thermally coupled to the light source to dissipate the heat loss proximally. The heat pipe extends into the headpiece of the endoscope, where a heat sink is located. This heat sink is thermally coupled to the heat pipe and absorbs the heat loss from the heat pipe, dissipating it directly or via a housing of the headpiece to the surrounding environment. From EP 2 946 718 A1, an endoscope is known which has a long, tubular shaft, a heat-generating heat source, and a heat pipe extending longitudinally inside the shaft and thermally coupled to the heat source in order to absorb heat from and dissipate it. The heat pipe is thermally coupled to the shaft over at least a portion of its length and circumference between its distal and proximal ends to dissipate heat from the heat pipe to the surroundings. In DE 10 2014 107 205 A1, an optical medical instrument, in particular an endoscope or exoscope, is disclosed, which has an elongated tubular shaft, a heat-generating heat source, and a heat pipe which extends inside the shaft in the longitudinal direction of the shaft and has a distal heat pipe end and a proximal heat pipe end, wherein the heat pipe is thermally coupled to the heat source in order to absorb heat from it and to dissipate it from the heat source. DE 10 2004 045 502 A1 relates to an expandable medical instrument for endoscopic procedures comprising a base body, a handle attached to the base body, and at least two spatula blades connected to the handle, which can be adjusted parallel and / or at an angle to each other via an adjustment mechanism between a closed initial position and at least one working position. However, it has been found that with the aforementioned endoscopes, the heat generated within the endoscope, particularly in a proximal end region, is not always optimally dissipated or distributed. Thus, the dissipation and distribution of heat in the aforementioned endoscopes can lead to a temperature distribution on the endoscope's surface that is not optimal, especially in the initial phase of an endoscopic procedure when the endoscope is still cold, i.e., largely at ambient temperature. It is an object of the present invention to provide an improved endoscope, in particular an improved mediastinoscope, wherein the endoscope or the mediastinoscope is improved, in particular with regard to heat management. Furthermore, it is an object of the present invention to provide a corresponding method for operating an endoscope and a method for manufacturing such an endoscope. This problem is solved by an endoscope according to claim 1 and by a method for manufacturing an endoscope according to claim 11. Advantageous further developments of the invention result from the dependent claims. An endoscope according to the invention is preferably a medical endoscope, in particular a mediastinoscope; however, the endoscope can also be, for example, a laryngoscope or an endoscope or endoscopic instrument suitable for other applications. Preferably, the endoscope is a video endoscope, and in a particularly preferred embodiment, a video mediastinoscope. An endoscope according to the invention has a long shaft, which is dimensioned, in particular, for insertion into an internal cavity of a human or animal body through a natural or artificially created body opening. The shaft is preferably rigid and may have an outer shaft, which may, for example, be an approximately cylindrical tube or spatula-shaped. Furthermore, the endoscope has a head section arranged at a proximal end section of the shaft. The head section may, for example, be designed as a handle or part of a handle, or it may be designed for attaching a handle or part of a handle; alternatively, the head section may also be a proximal end section of the shaft. Preferably, the head section projects from the shaft transversely to a longitudinal direction.The head section contains at least one heat source which emits waste heat during operation of the endoscope. Within the shaft, at least one heat pipe extends, essentially along one longitudinal direction of the shaft, with a proximal end section of the at least one heat pipe being thermally coupled to the heat source. "Thermal coupling" here refers to a direct contact, for example, a planar contact, or a connection via a thermally conductive material or one or more components made of thermally conductive materials, where the contact or connection is suitable for heat transfer. Suitable thermally conductive materials include, in particular, metallic materials, thermal paste, or thermally conductive adhesive. In this context, such a thermally conductive connection, referred to as thermal coupling, is specifically a connection over a distance that is significantly shorter than the length of the shaft or shorter than the diameter of the endoscope shaft.In the presence of a temperature gradient, heat transfer occurs via thermal coupling. The heat pipe is thermally coupled to the heat source, particularly to dissipate the heat loss, and is arranged distally in the shaft to conduct at least some of this heat loss. The heat pipe can also be referred to as a "heat pipe". Furthermore, the endoscope has an optical system for capturing an image of an object field within the cavity, which is sealed on the object side by a cover glass located in a distal end section of the shaft. The optical system can be located within the distal end section of the shaft and may, for example, comprise a lens and an electronic image sensor connected to the lens, or it can extend within the shaft to the proximal end section. In particular, the optical system extends parallel to a longitudinal axis of the shaft. The cover glass preferably has a flat surface, at least on the object side, which, depending on the viewing direction of the endoscope and the design of the lens, can be perpendicular, oblique, or parallel to the longitudinal axis of the shaft.The cover glass closes off the optical system, particularly on the distal side, and can, for example, form part of a distal end surface of the endoscope or be set back in a proximal direction relative to a distal end of the shaft. According to the invention, the heat source arranged in the head of the endoscope is at least one light source for generating illumination radiation, which can be guided to the distal end section of the shaft, for example, by optical fibers running within the shaft, to illuminate the cavity or the object field within the cavity. Furthermore, according to the invention, the at least one heat tube extends distally to the distal end section of the shaft and thus at least approximately to the level of the coverslip. At least one distal end section of the heat tube is thermally coupled to the distal end section of the shaft. In particular, the distal end or the distal end section of the heat tube is thermally coupled to the outer shaft, in which the coverslip may be embedded or by which the coverslip may be at least partially enclosed.Due to thermal coupling, heat transfer occurs particularly perpendicular to the longitudinal direction of the shaft. According to the invention, it has been recognized that the waste heat generated during the operation of the endoscope by the at least one light source can be used to selectively heat surface areas of the endoscope for which a higher temperature is advantageous. This applies in particular to surface areas in the distal end section of the shaft, for example, to a surface of the distal end section of the outer shaft and to the cover glass of the optical system. The heat management according to the invention is thus not only aimed at dissipating the waste heat, but also at its targeted distribution and use for heating surface areas. Because the heat source is a light source for generating the illumination radiation, because the heat tube extends to the distal end of the shaft, and because at least one distal end of the heat tube is thermally coupled to the distal end of the shaft, the waste heat from the light source generated during operation of the endoscope can be used to selectively heat the distal end of the endoscope shaft. This enables targeted heating of the surface of the distal end of the endoscope shaft, particularly when the distal end of the heat tube is thermally coupled to the outer shaft.This makes it possible, for example, to ensure that after the endoscope is put into operation, the section of the endoscope shaft that first comes into contact with the patient's body tissue is heated first and, for example, when the endoscope is inserted into the body opening, already has a surface temperature close to the patient's body temperature. Furthermore, by thermally coupling the heat pipe, which is thermally connected to the at least one light source for dissipating heat loss, to the shaft in the section of the shaft where the cover glass of the endoscope's optical system is located, the cover glass, which seals the optical system on the object side, is at least slightly warmed by the heat loss from the light source. This is particularly advantageous in the initial phase of an endoscopic procedure, since the shaft of the endoscope is often significantly cooler than the temperature of the cavity when inserted into the body cavity. This can cause moisture present in the cavity to condense on the cover glass and impair the endoscopic view. In this way, fogging of the cover glass can be prevented and the endoscopic view improved. Preferably, the optical system is housed in an optical shaft that extends parallel to the longitudinal axis of the endoscope shaft, and whose distal end section is thermally coupled to the distal end section of the shaft, particularly to the outer shaft. The optical shaft can be permanently connected to, or inserted into, the endoscope shaft and thermally coupled to it, at least partially, by soldering or thermally conductive adhesive. The optical shaft can be sealed distally by the cover glass. The optical shaft can be hermetically sealed, and may be formed by an approximately cylindrical tube in whose distal end the cover glass is hermetically sealed.The optical shaft can also incorporate an electronic image sensor, which can also be arranged in the distal end section of the optical shaft. The optical system comprises an endoscope objective lens that generates an image of the object field on a sensor surface of the image sensor. Since the at least one heat pipe extends into the area of ​​the objective lens and the coverslip, sufficient heat transfer to the distal end section of the optical shaft and thus to the coverslip can advantageously be achieved. The heat transfer can be further improved by thermally coupling the optical shaft, at least in its distal end section, to the shaft or the outer shaft, so that the heat transfer also occurs essentially transversely to the longitudinal direction of the shaft. Preferably, the at least one heat pipe can be thermally coupled to the shaft in a central section, for example over a portion of its length or over substantially its entire length running within the shaft. In particular, the heat pipe can be thermally coupled to the outer shaft in its central section and to the at least one heat pipe running within the shaft for at least a portion of the outer shaft's length, for example over half or three-quarters of its length. The outer shaft is preferably designed to be highly thermally conductive, for example made of a metallic material. In this way, a large or predominant portion or nearly the entire outer surface of the shaft can be used to dissipate the waste heat generated by the light source; in particular, the outer shaft can serve as a heat sink.This allows for efficient heat dissipation in addition to targeted heating of the distal end of the shaft. Furthermore, it more reliably prevents any surface of the shaft that comes into contact with the patient's body tissue from exceeding a maximum permissible temperature. According to a particularly preferred embodiment of the invention, the shaft has an outer shaft with a projecting section extending distally beyond the coverslip, wherein the at least one heat pipe extends distally only to the coverslip or approximately to the coverslip. In particular, it can be provided that the at least one heat pipe extends distally only or approximately to the level of the objective lens or an electronic image sensor arranged in the distal end section of the optical shaft. The outer shaft can, for example, be designed as a tube or as a spatula. According to a particularly advantageous embodiment, the endoscope is designed as a mediastinoscope, wherein the shaft is formed by a longitudinally slotted tube having an internal, longitudinally extending thickening in which the optical shaft is embedded. At its distal end, the shaft has an obliquely cut section that projects distally beyond the distal end of the optical shaft. This section creates a working space within which manipulations, such as biopsy sampling, can be performed under endoscopic visualization when using the mediastinoscope. Because the outer shaft has this projecting section extending distally beyond the coverslip, and because the at least one heating tube does not extend into it, a design is created that allows the coverslip to be heated in such a way that it represents the warmest surface area within the working space. This effectively prevents the coverslip from fogging up. According to the invention, the at least one heat pipe is inserted into a blind hole extending longitudinally in the shaft from the proximal direction. The blind hole is specifically introduced into an outer shaft of the endoscope from the proximal direction and closed distally. According to the invention, the blind hole is further connected near its distal end by a transverse bore to another bore in the shaft extending longitudinally, and the at least one heat pipe is embedded in thermally conductive adhesive within the blind hole.By inserting at least one heat pipe into a blind hole, thus providing a particularly large surface area for heat transfer, and by thermally coupling the at least one heat pipe to the shaft, especially the outer shaft, using thermally conductive adhesive, sufficient thermal coupling for transferring at least some of the heat loss from the light source to the shaft or the outer shaft can be achieved in a simple manner. Heat transfer can be further improved if the at least one heat pipe is inserted into the blind hole with tight tolerances.By connecting the blind hole to the longer longitudinal hole near its distal end via a transverse bore, excess thermally conductive adhesive can escape from the distal area of ​​the blind hole through the transverse bore. This prevents the build-up of back pressure that would otherwise hinder further insertion of the heat tube into the blind hole. This simplifies the manufacturing of the endoscope. Furthermore, it is preferred that the additional longitudinal bore is designed as a through bore in the shaft, particularly the outer shaft, extending longitudinally along the shaft and in which the optical system is accommodated or into which the optical shaft is inserted. This allows for both a simple design and easy assembly, as well as particularly efficient thermal coupling of the at least one heat pipe to the shaft. It is particularly advantageous to provide that the at least one blind hole, the at least one transverse hole, and the further longitudinal hole are formed in an outer shaft of the shank, wherein the outer shaft is formed in one piece, preferably from a metallic material, for example, stainless steel. The outer shaft can, for example, be tubular or spatula-shaped. The one-piece design further improves heat transfer. Such a one-piece outer shaft made of metallic material can, for example, be manufactured by laser sintering. Preferably, the endoscope has two heat pipes arranged on both sides of the optical system or the optical shaft, in particular symmetrically to the optical shaft, and running at least partially parallel to the optical system or the optical shaft. In this way, further improved heat transfer to the shaft or outer shaft and to the cover glass can be achieved. It is further preferred that the light source is formed by at least one light-emitting diode (LED) and an LED carrier on which the at least one LED is mounted, wherein the at least one heat pipe is thermally coupled to the LED carrier. In a further preferred embodiment, an optical waveguide is optically coupled to the at least one LED, extending through the shaft to its distal end section and designed to transmit the illumination radiation generated by the light source to an object field to be observed. The at least one LED, together with the proximal end of the optical waveguide, can be encapsulated with a potting compound to at least largely prevent the ingress of moisture into the light source. The at least one LED can be arranged transversely to the longitudinal direction of the shaft. According to a further embodiment, the endoscope has a handle comprising a housing, the housing of which contains an electronic unit. This electronic unit has a casing that rests flatly or form-fittingly against an inner surface of the housing. The handle can be formed wholly or partially by the head of the shaft or be connected to the head of the shaft; in particular, the housing of the handle can be attached to the head. The handle can, for example, be angled at 90° to the longitudinal direction of the shaft. The electronic unit comprises, in particular, electrical and electronic circuits for supplying and controlling the light source and / or for supplying and controlling an electronic image sensor and / or for image processing or image preprocessing of the image signals supplied by the electronic image sensor. The casing of the electronic unit can be hermetically sealed. Accordingly, the endoscope comprises at least two heat sources: the light source and the electronics unit. To dissipate the waste heat generated by each heat source, two corresponding heat sinks with separate heat paths are provided. The waste heat emitted by the electronics unit is efficiently transferred to the handle housing via the flat contact area of ​​the electronics unit's casing and from there to the surrounding environment. This flat contact area can be ensured by appropriately designed heat exchange surfaces on the casing and the housing. The use of thermal paste can further improve heat transfer. The electronic unit can, in particular, comprise a circuit board populated with electronic circuits and a metallic support, wherein the circuit board and the support can be thermally coupled to the housing of the electronic unit by means of thermal paste or thermally conductive adhesive; in particular, the circuit board can be thermally coupled to the support and the support to the housing. This allows for further improved dissipation of the waste heat generated by the electronic unit. According to a non-inventive method for operating an endoscope, in particular a mediastinoscope, wherein the endoscope comprises a long shaft and a head section arranged at a proximal end section of the shaft, a light source arranged in the head section is activated, and at least a portion of the heat loss generated by the light source is conducted via at least one heat pipe, the proximal end section of which is thermally coupled to the light source and which extends within the shaft, to a distal end section of the shaft. This allows the heat loss from the light source to be used simply to heat the distal end section of the shaft, and in particular, a surface of the distal end section of an outer shaft of the endoscope and / or a coverslip that seals an optical system of the endoscope on the object side can be heated. This is particularly advantageous at the beginning of an endoscopic procedure.The endoscope is designed in particular as described above and is preferably a video mediastinoscope. It may be particularly advantageous to activate the light source some time before using the endoscope in order to achieve an optimal temperature distribution of the endoscope's surface right from the start of the procedure. According to a method for manufacturing an endoscope according to the invention, an outer shaft of the endoscope is provided, which has at least one blind hole extending proximally into the outer shaft, a further longitudinal hole, and a transverse hole connecting the blind hole to the longitudinal hole near its distal end. The blind hole is at least partially filled with thermally conductive adhesive. A heat pipe is then inserted into the blind hole from the proximal direction, with the thermally conductive adhesive escaping through the transverse hole into the longitudinal hole. An optical shaft is inserted into the longitudinal hole, and excess thermally conductive adhesive can be removed from the longitudinal hole. The method may include further steps. The endoscope may, in particular, be configured as described above. In a particularly preferred manner, the outer shaft, which contains the at least one blind hole, the transverse hole and the further longitudinal hole, is formed in one piece and is particularly manufactured using the laser sintering process. It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention. Further aspects of the invention will become apparent from the following description of a preferred embodiment and the accompanying drawing. The drawings show: Fig. 1 an embodiment of an endoscope according to the invention in a longitudinal section; Fig. 2 an enlarged longitudinal section of the shaft and head of the endoscope according to Fig. 1; Fig. 3 a cross-section through the shaft and head of the endoscope according to Fig. 1; Fig. 4 a longitudinal section through the distal end section of the shaft of the endoscope according to Fig. 1 with a horizontal section plane; Fig. 5 a cross-section through the lower region of the handle of the endoscope according to Fig. 1. Figure 1 shows an endoscope according to an embodiment of the present invention in a longitudinal sectional view, and Figure 2 shows an enlarged longitudinal sectional view of the shaft and the head, the section plane of the endoscope being vertical in each case and approximately corresponding to a median plane of the shaft and the handle. Here and in the following, positional and directional references refer to the position of the endoscope shown in Figure 1. In the illustrated embodiment, the endoscope is a mediastinoscope, in particular a video mediastinoscope. However, the invention is not limited to this; an endoscope according to the invention can be designed accordingly, for example, as a laryngoscope or for other endoscopic applications. As shown in Fig. 1, the mediastinoscope 1 comprises an elongated shaft 10, designed for insertion into the mediastinum through an incision, and a handle 50. The shaft can be approximately 10–40 cm long, for example, about 20 cm. The handle 50 is arranged at a proximal end section 11 of the shaft 10 and, with respect to the position of the mediastinoscope 1 shown in Fig. 1, projects downwards from the shaft 10 at approximately a right angle. The shaft 10 has an outer shaft, which in the illustrated embodiment is formed by an approximately cylindrical tube 12 having a longitudinally extending slot. The tube 12 represents the blade of the mediastinoscope 1 and is made, for example, of stainless steel. The tube 12 encloses a longitudinally extending cavity 13 through which instruments, for example, for taking biopsies, can be inserted.In the distal end section 14 of the shaft 10, opposite the proximal end section 11, the cavity 13 opens into a working chamber 15. In the lower part of the tube 12, an internal thickening is arranged, which has a longitudinal bore into which an optical shaft 20 is inserted and firmly connected to the tube 12, for example by soldering or bonding with thermally conductive adhesive. An image acquisition unit 21 is housed within the optical shaft 20, comprising a lens 22 and an electronic image sensor 23. The electronic image sensor 23 can be, for example, a CCD or MOSFET sensor. The image signals generated by the electronic image sensor 23 are transmitted via a flexible circuit board 24 to an electrical connector 25 at the proximal end of the optical shaft 20.Further details of the arrangement and electrical connections of the electronic image sensor 23 are described in the German patent application filed on the same day as the present application by the same applicant entitled “Endoscope and method for manufacturing an endoscope” (our mark: KST082), which is incorporated into the present application by reference in this respect. The optical shaft 20, together with a proximal connector housing 26, forms a hermetically sealed space. For this purpose, the connector 25 is hermetically sealed within the connector housing 26, and the distal end of the optical shaft is sealed by the cover glass 27, which is also hermetically sealed. Further details of the hermetically sealed design of the optical shaft 20 together with the connector housing 26 are described in the German patent application entitled "Video endoscope" (our reference: KST083), filed on the same day as the present application by the same applicant, which is incorporated into the present application by reference. The tube 12 of the shaft 10 is obliquely cut distally and forms a projecting, overhanging section 16 extending distally beyond the optical shaft and the position of the coverslip 27. This overhanging section 16 of the tube 12 encloses the working space 15, which can be used for surgical manipulations under endoscopic visualization. For this purpose, the objective lens 22 is designed for a viewing angle oblique to the longitudinal direction of the shaft 10, and the coverslip 27 is positioned at a corresponding angle. Figures 1 and 2 further show that a head section 30 is attached to the proximal end section 11 of the shaft 10. This head section comprises a housing 31 in which the connector housing 26 and a light source 32 are accommodated. Electrical connecting leads (su) are also accommodated in the housing 31. The light source 32 comprises an LED 33, which is mounted on a carrier board 34 and connected there to electrical leads 35. An optical fiber 36, formed by a strand of optical fiber, is optically coupled to the LED 33 and transmits the illumination light generated by the LED 33 to the distal end section 14 of the shaft 10, where it exits the optical fibers to illuminate an object area or the working area 15. The optical fiber strand is held in an optical fiber holder 37. The carrier board 34 is attached to a metallic carrier 38, which is mounted on the inside of the headboard housing 31. Figure 3 shows a cross-section through the shaft 10 and the head 30 in the area of ​​the LED 33, viewed from the proximal direction. As shown in Figure 3, the LED 33 is optically coupled to the light guide 36, with the proximal end of the optical fiber strand forming the light guide 36 being held in the light guide socket 37. The light guide 36 runs below and laterally to the side of the optical shaft 20 and continues distally through the tube 12 of the shaft 10. Figure 3 also shows that the LED 33 is mounted on the LED carrier board 34, which is attached to the carrier 38 and thermally connected to it, for example, by full-surface contact. Two heat pipes (40, 40') are inserted into bores in the carrier 38 and thermally coupled to the carrier 38 using thermally conductive adhesive. As shown in Figure 3,As indicated by arrows 41 and 42, the heat generated during the operation of the LED 33, which is conducted via the LED board 34 to the carrier 38, is partly introduced directly into the head housing 31 (arrow 41) and largely dissipated by the heat pipes 40 and 40' (arrow 42). The heat flow from the LED 33 through the LED board 34 and within the metallic carrier 38 is indicated by arrows 43 and 44. As also shown in Fig. 3, the tube 12 of the shaft 10 is approximately cylindrical, but flattened on its upper side in its proximal end section 11. In the lower region of the tube 12, it has a thickening that extends longitudinally along the tube 12 as an inner bead 17. A continuous central longitudinal bore 18 and two blind bores 45, 45' running parallel to it laterally are provided in the bead 17. The heat pipes 40, 40' are guided in these bores and are each embedded in thermally conductive adhesive 47, 47' and thermally coupled to the tube 12. The optical shaft 20 and the light guide 36 run in the longitudinal bore 18. Furthermore, Fig. 3 indicates that a housing 51 of the handle 50 is attached to the head housing 31 by means of a seal 52. An electronics unit 60 is included inside the housing 51 (see below). As shown in the horizontal longitudinal section through the distal end section 14 of the shaft 10 in Fig. 4, the blind bores 45, 45' terminate distally shortly before the distal end of the optical tube 20. The optical tube 20, in whose distal end section the lens 22 and the electronic image sensor 23 are housed, is hermetically sealed by the cover glass 27. The distal end section of the optical fiber 36 is indicated laterally to the optical tube 20. Transverse bores 46, 46' are provided in the tube 12 near the distal end of the blind bores 45, 45', through which the thermally conductive adhesive 47, 47', in which the heat pipes 40, 40' are embedded (see Fig. 3), can exit into the longitudinal bore 18 during assembly. The distal end section of the heat pipes 40, 40' shown in Fig. 4 is thermally coupled to the tube 12 via the thermally conductive adhesive 47, 47'. As shown in Fig.As also shown in Fig. 4, the overhanging section 16 of the tube 12 forms the working space 15. Furthermore, the longitudinally continuous slot 19 of the tube 12 can be seen at the distal end of the tube 12 (see also Fig. 3). In Fig. 5, approximately extending downwards from the cross-section shown in Fig. 3, the handle 50 is shown in a cutaway view in the area of ​​the housing 51. The electronic unit 60 is housed within the housing 51 of the handle 50. This unit has a metallic casing 61 in which an aluminum carrier 62 is mounted, supporting the power supply board 63. The power supply board 63 has electronic circuits for controlling the LED 33, for supplying power to the electronic image sensor 23, and for image preprocessing of the signals supplied by the electronic image sensor 23. For this purpose, the power supply board 63 is connected to the image sensor 23 and the LED 33, respectively, via a connector 64 and the corresponding lines 28 and 35 (see Fig. 2). The lines 28 and 35 can be designed, for example, as flexible circuit boards or ribbon cables.Furthermore, the power supply board 63 is connected via connector 64 and lines 57 to a plurality of buttons 53, which are inserted into the housing 51 of the handle 50 and by means of which various functions of the mediastinoscope 1 can be controlled, such as the brightness of the illumination and an electronic zoom function. The power supply board 63 is also connected via connector 65 to connecting lines 66, which serve for connection to an external power supply and evaluation unit, which may also include a monitor and other operating elements. The aluminum carrier 62 is adapted to the component placement of the power supply board 63 and, for example, has sufficient thickness to largely fill the gap between the housing 61 and the power supply board 63 in the areas where most of the heat loss occurs during operation of the power supply board 63. The power supply board 63 is also thermally coupled to the aluminum carrier 62 by means of thermal paste or adhesive, and the aluminum carrier 62 is in turn thermally coupled to the housing 61 by means of thermal paste or adhesive. A gap between the power supply board 63 and the housing 61 can also be filled with thermal paste or adhesive. The housing 61 rests flat against the inside of the enclosure 51. Additional thermal paste can be used to improve the thermal coupling of the electronic unit 60 to the enclosure 51. The heat transfer through the aluminum carrier 62 or thermal paste or adhesive into the enclosure is shown in Fig.5 indicated by the arrows 67. The electronic unit 60 is hermetically sealed, for which the connectors 64 and 65 are hermetically sealed within the metallic housing 61. As mentioned above, the optical shaft 20, together with the connector housing 26, is also hermetically sealed. The mediastinoscope 1 is completely sealed, for which, for example, the seal 52 is provided. The mediastinoscope 1 can thus be easily cleaned and sterilized without disassembly and, with appropriate design, is entirely autoclavable. However, since the ingress of moisture into the interior of the head housing 31 cannot be completely prevented due to the seals 52 and the properties of glass fibers, the LED 33, including the proximal end of the light guide 36 optically coupled to the LED 33, is sealed.the light guide socket 37 is enclosed in potting compound (not shown in the figures) to further seal the LED 33 and to protect it as much as possible against the ingress of moisture. As indicated in Fig. 5, the electronic unit 60 is screwed to the head housing 31 by means of screws 54. However, the screws 54 are not accessible when the mediastinoscope 1 is assembled. The housing 51 of the handle 50 is held to the electronic unit 60 by a retaining nut 55. To replace the electronic unit 60, for example in the event of damage, the retaining nut 55 is loosened, for which a special tool is required. The housing 51 of the handle 50 can then be pulled off the cover 61 of the electronic unit 60, so that the screws 54 become accessible and can be loosened. The leads 57 are of sufficient length that the connector 64 only needs to be disconnected after the cover has been removed. After disconnecting the connectors 64 and 65, the electronic unit 60 can then be removed and replaced.In this way, it is possible to replace the electronic unit 60 without having to replace the shaft 10 with the optical shaft 20 at the same time. Further details of the hermetically sealed design of the electronic unit 60 as well as the sealing and disassemblability of the mediastinoscope 1 are described in the German patent application filed on the same day as the present application by the same applicant entitled “Video endoscope” (our mark: KST083), which is incorporated into the present application by reference in this respect. When the mediastinoscope 1 is put into operation, heat is generated in the power supply board 63 and in the LED 33. As described above, the heat from the power supply board 63 is transferred via the aluminum carrier 62 and the housing 61 to the housing 51 of the handle 50, whereby heat transfer can be improved by thermal paste or thermal adhesive. A small portion of the heat from the LED 33 is conducted via the carrier board 34 and the carrier 38 into the head housing 31, while the majority is absorbed by the heat pipes 40, 40' (see Fig. 3). The heat pipes 40, 40' transport the relevant portion of the heat from the LED 33 distally into the shaft 10 of the mediastinoscope 1 and at least partially into the distal end section 14 of the shaft 10 (see Fig. 4).The portion of the heat loss transferred up to that point heats the tube 12 in the region of the distal end section 14 of the shaft 10 via the thermally conductive adhesive 47, 47', in which the heat pipes 40, 40' are embedded in the blind bores 45, 45'. Since the optical shaft 20 is completely enclosed by the tube 12, the optical shaft 20, as well as the objective lens 22 and the cover glass 27 inserted into the distal end of the optical shaft 22, are also heated. Even a slight heating of the cover glass 27 can be sufficient to prevent fogging of the cover glass 27 when the shaft 10 is inserted into an internal cavity. The heat loss from the power supply board 63, introduced into the housing 51, and the portion of the heat loss from the LED 33 introduced into the head housing 31, is essentially dissipated from there into the surroundings. The remaining heat loss from the LED 33 is conducted through the heat pipes 40, 40' into the shaft 10 and also dissipated to the surroundings via the tube 12 or used to heat the cover glass 27. The electronic image sensor 23 also generates heat loss during operation, but this is generally less than the heat loss from the LED 33. In Fig. 4, the arrow 48 symbolically indicates a corresponding heat flow within the heat pipe 40', which is generally directed distally, but can, in principle, also be directed proximally, depending on the temperature gradient and the heat output of the electronic image sensor.The heat flow from the heat pipe 40' to the surface of the tube 12 of the shaft 10 is indicated by arrow 49. As can be seen in Fig. 4, the heat transfer within the tube 12 occurs essentially or at least partially transversely to the longitudinal direction of the tube 12. The thermal management system according to the invention ensures that the heat loss, which is primarily generated in the proximal region of the mediastinoscope, is optimally dissipated via the distal and proximal areas of the mediastinoscope's surface, while preventing heat-induced damage to body tissue during the procedure. Simultaneously, some of the heat loss can be used to warm the distal end of the mediastinoscope, thereby also warming the coverslip; this prevents fogging of the coverslip, especially at the beginning of surgery. Furthermore, the mediastinoscope is designed to allow for easy handling, cleaning, and sterilization, for example, by autoclaving. For the sake of clarity, not all reference symbols are shown in all figures. Reference symbols not explained in a particular figure have the same meaning as in the other figures. Reference symbol list 1 Mediastinoscope 10 Shaft 11 Proximal end section 12 Tube 13 Cavity 14 Distal end section 15 Working space 16 Overhanging section 17 Bead 18 Longitudinal bore 19 Slot 20 Optical shaft 21 Image acquisition unit 22 Lens 23 Image sensor 24 Flexible circuit board 25 Connector 26 Connector housing 27 Cover glass 28 Leads 30 Head section 31 Head section housing 32 Light source 33 LED 34 Carrier board 35 Leads 36 Light guide 37 Light guide socket 38 Carrier 40, 40' Heat pipe 41 Arrow 42 Arrow 43 Arrow 44 Arrow 45, 45' Blind hole 46, 46' Transverse hole 47, 47' Thermal adhesive 48 Arrow 49 Arrow 50 Handle 51 Housing 52 Gasket 53 Button 54 Screw 55 Union nut 57 Cables 60 Electronic unit 61 Housing 62 Aluminum carrier 63 Power supply board 64 Connector 65 Connector 66 Connecting cables 67 Arrow

Claims

Endoscope, in particular mediastinoscope (1), with a long shaft (10) and a head (30) arranged at a proximal end section (11) of the shaft (10), wherein a heat source is arranged in the head (30), wherein at least one heat tube (40, 40') extends within the shaft (10), wherein a proximal end section of the at least one heat tube (40, 40') is thermally coupled to the heat source, and wherein the endoscope has an optical system which is closed by a cover glass (27) arranged in a distal end section (14) of the shaft (10), wherein the heat source is a light source (32) for generating illumination radiation, the at least one heat tube (40, 40') extends distally into the distal end section (14) of the shaft (10), and at least one distal end section of the heat tube (40, 40') is thermally coupled to the distal end section (14) of the shaft (10), characterized in thatthat the at least one heat pipe (40, 40') is inserted into a blind hole (45, 45') of the shaft (10) extending in the longitudinal direction of the shaft (10), that the blind hole (45, 45') is connected near its distal end by a transverse hole (46, 46') to another longitudinal hole (18) of the shaft (10), and that the at least one heat pipe (40, 40') is embedded in the blind hole (45, 45') in thermally conductive adhesive (47, 47'). Endoscope according to claim 1, characterized in that the optical system is received in an optical shaft (20) which extends in the shaft (10) of the endoscope and whose distal end section is thermally coupled to the distal end section (14) of the shaft (10). Endoscope according to claim 1 or 2, characterized in that the at least one heat tube (40, 40') is thermally coupled to the shaft (10) in a central section. Endoscope according to one of the preceding claims, characterized in that the shaft (10) has an outer shaft which has a projecting overhanging section (16) extending distally beyond the cover glass (27), wherein the at least one heat tube (40, 40') extends distally only to the cover glass (27) or approximately to the cover glass (27). Endoscope according to one of the preceding claims, characterized in that the further longitudinal bore (18) is a through bore, wherein the optical system is accommodated in the through bore. Endoscope according to one of the preceding claims, characterized in that the shaft (10) comprises an outer shaft having the blind bore (45, 45'), the transverse bore (46, 46') and the further longitudinal bore (18), wherein the outer shaft is formed in one piece. Endoscope according to one of the preceding claims, characterized in that the endoscope comprises two heat tubes (40, 40') arranged on both sides of the optical system. Endoscope according to one of the preceding claims, characterized in that the light source (32) comprises at least one LED (33) and an LED carrier (38), wherein the at least one heat tube (40, 40') is thermally coupled to the LED carrier (38). Endoscope according to one of the preceding claims, characterized in that the endoscope has a handle (50) with a housing (51), wherein an electronic unit (60) is received in the housing (51), which has a cover (61) which is in contact with an inner surface of the housing (51) in a planar or form-fitting manner. Endoscope according to claim 9, characterized in that the electronic unit (60) comprises a circuit board and a metallic support of the circuit board, which are thermally coupled to the shell (61) by means of thermal paste and / or thermal adhesive. Method for manufacturing an endoscope, in particular a mediastinoscope (1), wherein an outer shaft of the endoscope is provided, which has at least one blind bore (45, 45') extending into the outer shaft from a proximal direction, a further longitudinal bore (18) and a transverse bore (46, 46') which connects the blind bore (45, 45') to the longitudinal bore (18) near its distal end, the blind bore (45, 45') is at least partially filled with thermally conductive adhesive, a heat tube (40, 40') is inserted into the blind bore (45, 45') wherein the thermally conductive adhesive escapes through the transverse bore (46, 46') into the longitudinal bore (18), and an optical shaft (20) of the endoscope is inserted into the longitudinal bore (18).

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