DE202010017255U1 - Endoscopic instrument with a heating for the end window - Google Patents

Abstract

Endoscopic instrument with an observation shaft (12, 54, 62), the distal end (14) of which is hermetically sealed off from the outside by a transparent window (16, 66, 86), and with a heater (30) for heating the window ( 16, 66, 86), characterized in that the heater (30) has a transparent, electrically conductive film layer (32, 68, 92) applied to the window (16, 66, 86).

Description

The invention relates to an endoscopic instrument with an observation shaft, whose distal end is hermetically sealed to the outside through a transparent window, and with a heater for heating the window.

Such endoscopic instruments are widely used and are used in particular for minimally invasive surgery.

Through the viewing shaft, a visual observation can be made, for example, inside a body into which the endoscopic instrument is inserted.

Numerous embodiments for a variety of observation purposes are known.

In the case of rigid endoscopes, a glass lens system is usually accommodated in the interior of the observation shaft, in particular rod lenses in what is known as a HOPKINS optic. Through this optics, an image to be observed at the distal end is transmitted to the proximal end of the endoscopic instrument. The observation at the proximal end itself can take place, for example, via the human eye, in particular via an eyepiece.

It can also be a camera connected to the proximal end, which transmits the image, for example, to a monitor.

In flexible endoscopes, a chip, for example a CCD chip, is usually present in the distal end region of the observation shaft, which converts the incident image, that is to say the light, into electrical signals, which are then conducted to the proximal end.

Other instruments, such as laryngoscope blades, are known for inspection of the posterior pharyngeal space.

In all of these endoscopic instruments, the distal end of the viewing shaft must be hermetically sealed to the outside. This is because this end is inserted into the object to be observed and there comes into contact with any contamination. These contaminants may be body fluids, blood, wound secretions or others. When cleaning the instrument, especially when autoclaving, no moisture should get into the optics in the observation shaft.

For this purpose, it has become customary to complete the distal end of the observation shaft through a transparent window. The window, usually in the form of a glass pane, is connected via its peripheral peripheral edge to the inner surface of the distal end region of the observation shaft.

This connection can take place via an adhesive bond, in particular by hardening putties, or via a soldering material, for example tin solder or gold solder.

The solder joints have proven to be particularly resistant and durable sealing materials.

Since minimally invasive surgery has become widespread, such endoscopic instruments are very often in use, sometimes several times a day, and must undergo cleaning, sterilizing and, in particular, autoclaving processes in between, which represent considerable thermal and mechanical stresses. In so-called flash autoclaving, the instruments are heated to temperatures of 165 ° C and then cooled.

In practical use, the endoscopic instruments are prepared for a minimally invasive procedure. The temperatures prevailing at these locations are usually room temperature or, in some operating rooms, lower than room temperature.

Now, when an endoscopic instrument is inserted into a body, which usually has a temperature in the range of 37 ° C, it is observed that the distal outer surface of the window fogs. Since the inside of the body also has a relatively high humidity, there is considerable rainfall, which severely limits visibility.

Attempts have been made to heat such endoscopic instruments to body temperature prior to surgery, for example, by wrapping in electric blankets or plugging into containers with a suitably heated liquid, but there are significant hygienic problems.

Therefore, heating systems have been developed to heat the endoscope window from the inside of the shaft.

From the DE 10 2008 031 881 B3 an endoscopic instrument is known in which the window is heated. The heater consists of a heating ring which is pressed by a arranged inside the endoscope spring device to the proximal inner side of the window. The heating ring consists of a wire coil or a ring of electrical resistance material and occupies a circumferential annular area of the window.

As a result, the light or image entry cross-section of the window is reduced.

Another disadvantage is that the heater occupies a relatively large space in the interior of the distal end portion of the observation shaft and thus significantly reduces the actual possible observation cross-section.

If one considers that the diameters of endoscope shafts are in the range of a few millimeters, it is obvious that the space is already tight anyway, and a restriction by a heating ring with pressing device is unfavorable.

In the US 7,445,637 B2 an endoscopic instrument is described, in which the incident light or image is first guided through an optical lens system a bit into the interior of the observation shaft and then deflected by a prism by about 90 ° and passed to a CCD chip.

In the operation of such an endoscopic instrument, it has been found that heat is generated inside the endoscope, which leads to the heating of the interior and beyond the body temperature, for example, to 40 ° C.

Thus, a temperature gradient between the transparent window, which has already been heated by the body to about 37 ° C and the heated to about 40 ° C interior of the endoscope was detected. As a result, after a certain period of operation, moisture that is present in the interior of the endoscope can be deposited on the inside of the window. Therefore, a heater is provided, which is mounted flat on the long base side of the Umlenkprismas. The prism is first heated by means of this heater, this then forwards the heat to the optical elements up to the window, so that ultimately the window is also heated.

This heater is very energy-intensive and fits just for such constructions with a deflection prism. In endoscopes, where virtually all of the freely available interior of the observation shaft is occupied by the optics, such a heater can not be used.

It is therefore an object of the present invention to develop a heater to the effect that this effectively heats the window, without requiring a large amount of space.

According to the invention the object is achieved in that the heater has a applied to the window, transparent, electrically conductive film layer.

By providing an electrically conductive film layer covering the transparent window, it can be uniformly and effectively heated. Because the film layer is also transparent, it does not affect the light path through the window, which is extremely favorable and effective, especially in the case of endoscopes with a relatively small shaft cross-section. The necessary contact and power supply can be done inside the endoscope, without having to be occupied large space. By training as a layer, this adheres to the window, so that no additional measures such as pressure devices or the like must be taken. This is the case in particular in the case of a circular coating.

By direct coating of the window, an optimal heat transfer can be achieved, so that even low heat outputs are sufficient to heat the window, for example, to body temperature.

The materials for forming the film layer must show a certain ohmic resistance, which leads to heat flow of current, which can then be used directly to heat the window.

For small endoscopes thus already low heating power sufficient to ensure this heating process. As a result, it is also possible to work with relatively thin film layers, which contributes to the transparency and thus the luminous efficacy of the light passing through the window. The layer thickness can be, for example, 15-300 nm.

In one embodiment of the invention, the film layer is applied to the distal outer side of the window.

This measure has the advantage that the heater is mounted precisely at the critical point at which the condensation processes take place, namely on the outside of the window. That is, you can get along with extremely low heat outputs, which ensure that at least the distal outer portion of the window is heated to body temperature, so that no fogging can occur.

In one embodiment of this variant, the film layer is extending over a peripheral edge of the window, guided proximally and communicates there with contacts.

This measure has the advantage that the film layer can be applied virtually over the entire outer distal end surface and is continued to contact via the peripheral edge to the proximal end in the interior of the endoscope. This represents a particularly effective space and component-saving design of the heating.

In a further embodiment of this variant, the film layer is covered by a transparent insulating protective layer.

This measure now has several advantages. By forming an insulating layer, no passage of current from the heater into the body is possible. For surgical interventions, several medical devices can be used, which can meet during manipulation, especially in the distal end. Since most shafts of rigid endoscopes are made of metallic materials, thus current transitions could take place, which is now excluded by the insulating protective layer.

At the same time, the outer protective layer also provides mechanical protection of the window and, in particular, mechanical protection of the film layer applied thereto, so that these are protected against damage during handling. The insulating protective layer can, in particular, isolate the region of the conductive film layer guided proximally over the peripheral edge in relation to a metallic solder layer or against the observation shaft made of metal. The layer thickness of this protective layer can be in the range of 50 nm-20 μm.

In a further embodiment, the transparent insulating protective layer consists of quartz glass or sapphire glass.

On the one hand, these materials show excellent transparency, on the other hand they are extremely hard and in particular very scratch-resistant. Silica based on silica or sapphire glass based on alumina is available from the glass manufacturers.

Another advantage is that then the window, which usually also consists of glass, from cheaper glass materials, eg. B. simple boron glasses can be produced, which are less scratch resistant.

In a further embodiment of the invention, the film layer is applied to the inner side of the window.

This measure has the advantage that due to the attachment of the film layer on the inner side of this film layer is protected from external influences through the window itself. Here then the heating power must be chosen so that it is ensured that the outside of the window can be heated to such an extent by the film layer applied on the inside of the window that no fogging takes place.

From a structural point of view, the contacting is easier, since the contacting on the inner side of the window can be accomplished directly from the free available interior space.

This variant will be preferable if thin windows are present and the distal end of the observation shaft is subjected to less mechanical stress. This can be, for example, in devices in which the observation shaft is surrounded by other shafts and channels, and the outermost distal end of the observation shaft is possibly set back slightly.

In a further embodiment of the invention, the film layer consists of transparent conductive oxides, in particular selected from the group consisting of tin-doped indium oxide (ITO), fluorinated tin oxide (FTO), antimony-doped tin oxide (ATO), aluminum doped zinc oxide (AZO), delafossites, z. B. CuAlO ₂ , CuCrO ₂ , CuAl _x Cr _1-x O ₂ .

These oxidic materials are characterized by extreme hardness, high transparency and good conductivity.

These oxides are also extremely temperature resistant. They can therefore be applied by vapor deposition (PVD, CVD).

This also has the advantage that a coated with these oxides window can be easily soldered with high melting solders, such as tin solder, melting temperature> 220 ° C or gold solder, melting temperature> 280 ° C in the observation shaft without the risk that the film layer is affected by these high temperatures.

In a further embodiment of the invention, the film layer consists of transparent conductive polymers, in particular selected from the group consisting of poly (3,4-) ethylenedioxythiophene) (PEDOT); Poly (styrenesulfonate) (PSS); Poly (4,4-dioctylcyclopentadithiophen).

These conductive polymers have sufficient conductivity to be used as heating material and are applied to the window by wet or pad printing, for example.

In a further embodiment of the invention, the film layer consists of transparent conductive carbon nanotubes (CNT) or graphene.

These materials, which consist essentially of pure carbon, have excellent conductivity and extremely high temperature resistance.

The nanotubes have three-dimensionally branched carbon lattices that are very close to the diamond lattice structure. Graphene is dominated by two-dimensional hexagonal carbon crystals, which show very good electrical conductivity between the layers.

The aforementioned materials can be applied by conventional methods in the form of films. These methods are, for example, sol-gel processes, physical (PVD) or chemical (CVD) vapor deposition methods, or they can also be printed, e.g. B. by a so-called pad printing.

The geometry of the layer is designed so that, for example, in a heating on the outside of the window, the film layer is designed so that it also serves as a leading lead for Konnektierung on the inside of the window to make the power supply to the heater.

This geometry can be created by coating the window by appropriate masking, or the layer can be partially removed after a coating process.

In a further embodiment of the invention, a sensor is provided which detects the temperature of the window.

This sensor now allows to track the effect of the heater and to control accordingly.

In a further embodiment of the invention, the sensor is part of an electrical control circuit for controlling the temperature of the window.

It can be accomplished an active control loop, which regulates the amount of heating in dependence on the temperature detected by the sensor. This is a particularly effective heating to perform.

It is understood that the features mentioned above and those yet to be explained below can be used not only in said combination, but also in other combinations or in isolation, without departing from the scope of the present invention.

The invention will be described in more detail below with reference to some selected embodiments in conjunction with the accompanying drawings and explained. Show it:

1 a side view of a first embodiment of a window with a heater according to the invention,

2 one opposite the 1 side view rotated by 90 ° about the shaft axis,

3 a longitudinal section in the end of an observation shaft, in which the window of 1 and 2 is used,

4 schematically a side view of a complete instrument in which the window of 1 is installed,

5 a longitudinal section of a second embodiment in the region of the distal end of an observation shaft, and

6 one of the 5 corresponding section of a third embodiment of a window with a heater according to the invention.

One in the 1 to 4 illustrated first embodiment of an endoscopic instrument is in its entirety by the reference numeral 10 designated.

The instrument 10 is designed as a rigid endoscope and has an observation shaft 12 on, its distal end 14 through a window 16 is completed.

The window 16 has a circular glass pane 18 whose outer diameter is slightly smaller than the clear inner diameter of the observation shaft 12 , In particular from 1 and 2 it can be seen that the distal outer side 24 the round glass pane 18 with a film layer 32 is coated. This film layer is over two stripes 34 and 36 proximally over the peripheral edge 26 the disc 18 inside up to their inside page 28 guided. The Stripes 34 and 36 consist of the same material as the film layer.

On the inner side 28 the glass pane 18 are two contact points 38 and 40 present, with cables 42 and 44 are connected, via which an electric current can be supplied, in the illustrated embodiment, a direct current.

How out 4 you can see the two cables 42 and 44 over the entire length of the observation shaft 12 to a proximal head 52 of the instrument 10 guided. There they are to a lateral connection 56 led into which a plug 58 can be plugged in with a power source 60 connected is. This is a total of heating 30 accomplished.

That by the observation shaft 12 passed light or image becomes an observation port 54 guided. For example, an eyepiece can be attached to this connection in order to pass through the observation shaft with the human eye 12 to be able to watch through. An endoscopic camera can also be connected to this exclusion, which then forwards the image electrically and, for example, feeds it to a monitor, by means of which it is visualized.

As in particular from 3 is to be seen in the designed as a rigid endoscope instrument 10 inside a look 50 taken, which is usually constructed of rod lenses and a distal end-side lens.

Returning to 1 and 2 it can be seen that on the film layer 32 another protective layer 46 is applied, which in the illustrated embodiment of a cover 48 made of sapphire crystal. The diameter of the cover 48 is slightly larger than the diameter of the disc 18 and as large as the outer diameter of the observation shaft 12 ,

This will achieve how that particular out 3 it is apparent that this cover 48 an end cover of both the window 16 as well as the distal annular end edge of the observation shaft 12 represents.

The cover 48 made of sapphire crystal, for example, on the film layer 32 be pressed or glued, in which case care is taken that this adhesive bond is transparent. In addition, it may be connected to the frontal peripheral edge of the observation shaft.

The hermetically sealed to the outside connection between the window 16 and the observation shaft 12 via a soldered seam 20 that the complete peripheral edge 26 the glass pane 18 covered and thus also the space between this peripheral edge 26 and the corresponding inside 22 of the observation shaft 12 ,

In the illustrated embodiment, the soldered seam consists of a gold solder with a melting point of about 280 ° C.

The film layer 32 In the illustrated embodiment, it consists of tin-doped indium oxide (ITO), which by a pad printing process on the distal outer side 24 the glass pane 18 has been applied. At the same time, the two strips 34 and 36 made of the same material. The layer thickness can be in the range of 15-300 nm.

As mentioned above, numerous oxide conductive materials, so-called TCO (Transparent Conductive Oxides) are available, which can be applied by different methods on surfaces, such as a glass surface. These methods are either physical or chemical vapor deposition or the aforementioned pad printing.

Such metallic oxides have extremely high melting temperatures and are therefore particularly suitable for use in soldering operations, for example with tin solder (melting temperature above 220 ° C.) or gold solder (melting temperature above 280 ° C.).

For example, the melting temperature of ITO is 2000 ° C, ATO is about 1000 ° C, FTO is about 1000 ° C and AZO is about 500 ° C.

The same applies to the carbon nanotubes mentioned at the beginning (CNT = Carbone Nano Tubes) or the graphene, which have melting temperatures in the region of 1900 ° C.

Will that be in 1 to 4 used embodiment shown, ie with the outer sapphire crystal protective glass, then the material from which the glass pane 18 is made of the boron glasses are chosen, which are not so scratch resistant and are cheaper, because the outside is through the cover 48 protected.

The cover 48 Although it provides mechanical protection, it does not prevent the ingress of moisture or liquids, so the problem with these constructions is still the glass pane 18 can fog during insertion into a body. Therefore, the heater is provided, its film layer 32 the outer side 24 the glass pane 18 Protects against fogging by heating them to body temperature.

The film layer 32 also heats the outer protective layer 46 on, so that too, opposite the glass 18 significantly thinner sapphire glass is heated accordingly, so that even at this condensates can not precipitate.

The sapphire crystal material of the cover 48 is an insulator, so that not only the mechanical protection but also the required electrical safety is ensured by this cover.

Out 3 can be seen that on the inside of the glass 18 a sensor 51 attached, the temperature of the glass pane 18 detected.

This sensor 51 is connected to an electrical control circuit, not shown here, for controlling the temperature of the window. This control is in the power source 60 Integrates and regulates the heating power of the heater 30 depending on the sensor 51 recorded temperature. This can be a particularly effective and targeted heating of the window 16 be achieved.

At the in 5 illustrated second embodiment is the window 66 as previously described, on the distal outside with a film layer 68 coated from a transparent electrically conductive material, this for contacting via two strips 70 and 72 inside to cables 74 and 76 is guided.

Again, the window is here 66 over a soldered seam 64 into the distal end of an observation shaft 62 used. In contrast to the embodiment shown above, no cover is present here. Here are then materials for building the film layer 68 used, which are scratch-resistant.

This uncovered embodiment can be used in such cases when passing current from the film layer 68 not to be feared or uncritical.

At the in 6 illustrated third embodiment, the instrument has an outer shaft 80 on, in which the observation shaft 82 is used.

The distal end of the observation shaft 82 is again sealing to the outside via a circumferential soldering seam 84 with the window 86 connected.

In this embodiment, the inner side 88 of the window 86 with the film layer 92 coated, the again about corresponding unspecified here contacts with cables 94 and 96 is supplied with electricity.

In the illustrated embodiment is in the interior of the observation shaft 82 an image converter is provided which converts an incidental image into electrical signals, such as a CCD chip 98 who then transformed the image as electrical signals over a wire 100 leads to the proximal end.

Out 6 it can be seen that in addition to the observation 82 a channel 102 is available, which can serve for example for performing surgical instruments or lighting fibers or the like.

This variant can then be used if, despite the attachment of the film layer 92 on the inner side 88 of the window 86 It can be ensured that the outside can be heated as quickly as possible, so that it does not fog up.

Here, the problem of electrical current transgressions does not arise because the film layer 92 on the inside of the window 86 is appropriate.

This variant can then be used when the window 86 is relatively thin and the film layer 92 the appropriate heating power can provide to the outside of the window 86 to prevent fogging.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008031881 B3 [0018]
• US 7445637 B2 [0022]

Claims (11)

Endoscopic instrument, with an observation shaft ( 12 . 54 . 62 ), whose distal end ( 14 ) through a transparent window ( 16 . 66 . 86 ) is hermetically sealed to the outside, and with a heater ( 30 ) for heating the window ( 16 . 66 . 86 ), characterized in that the heating ( 30 ) one on the window ( 16 . 66 . 86 ) applied, transparent, electrically conductive film layer ( 32 . 68 . 92 ) having. Endoscopic instrument according to claim 1, characterized in that the film layer ( 32 . 68 ) on the distal outer side ( 24 ) of the window ( 16 . 66 ) is applied. Endoscopic instrument according to claim 1 or 2, characterized in that the film layer ( 32 . 68 ) over a peripheral edge ( 26 ) of the window ( 16 . 66 ) is guided proximally and there with contacts ( 38 . 40 ). Endoscopic instrument according to one of claims 1 to 3, characterized in that the film layer ( 32 . 86 ) by a transparent insulating protective layer ( 46 ) is covered. Endoscopic instrument according to claim 4, characterized in that the protective layer ( 46 ) consists of quartz glass or sapphire glass. Endoscopic instrument according to claim 1, characterized in that the film layer ( 92 ) on the inner side ( 88 ) of the window ( 86 ) is applied. Endoscopic instrument according to one of claims 1 to 6, characterized in that the film layer is composed of transparent conductive oxides, in particular selected from the group consisting of tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), Aluminum doped zinc oxide (AZO), delafossites such as CuAlO ₂ , CuCrO ₂ , CuAl _x Cr _1-x O ₂ . Endoscopic instrument according to one of claims 1 to 6, characterized in that the film layer is composed of transparent conductive polymers, in particular selected from the group consisting of poly (3,4-ethylenedioxythiophene) (PEDOT); Poly (styrenesulfonate) (PSS); Poly (4,4-dioctylcyclopentadithiophen). Endoscopic instrument according to one of claims 1 to 6, characterized in that the film layer is constructed of transparent conductive carbon nanotubes (CNT) or of graphene. Endoscopic instrument according to one of claims 1 to 9, characterized in that a sensor ( 51 ), which determines the temperature of the window ( 16 . 66 . 86 ) detected. Endoscopic instrument according to claim 10, characterized in that the sensor ( 51 ) Part of an electrical control circuit for controlling the temperature of the window ( 16 . 66 . 86 ).

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