Patent Description:
The disclosure relates to insertable medical vision devices, in particular disposable insertion endoscopes, and more specifically to a housing for the tip of the disposable insertion endoscope and the manufacture thereof.

Vision devices, such as insertion endoscopes, are well known devices for visually inspecting body cavities, such as human body cavities. Typically, an insertion endoscope comprises an elongated insertion tube with a handle at the proximal end as seen from the operator and visual inspections means, such as a built-in camera, at the distal end of the elongated insertion tube. Electrical wiring for the camera and other electronics such as LED lighting accommodated in the tip part at the distal end run along the inside of the elongated insertion tube from the handle to the tip part. Instead of using cameras, endoscopes may also be fibre-optic, in which case the optical fibres run along inside of the elongated insertion tube to the tip part.

In order to be able to manoeuvre the endoscope inside the body cavity, the distal end of the endoscope may comprise a bending section with increased flexibility, e.g. a number of articulated segments of which the tip part forms the distalmost segment. This is typically done by tensioning or slacking pull wires also running along the inside of the elongated insertion tube from the tip part through the remainder of articulated segments to a control mechanism of the handle. Furthermore, a working channel may run along the inside of the insertion tube from the handle to the tip part, e.g. allowing liquid to be removed from the body cavity or allowing the insertion of surgical instruments or the like into the body cavity.

As the name indicates, endoscopes, are used for seeing inside things, such as lungs or other human body cavities of a patient. Modern endoscopes are therefore typically equipped with a least one camera or similar image capturing device at the distal tip of the endoscope. Provided that sufficient light is present, this allows the operator to see where the endoscope is steered and to set the target of interest once the tip has been advanced thereto. This therefore normally requires illumination of the area in front of the distal tip of the endoscope, in particular the field of vision of the camera(s). One known way of achieving such illumination is to provide the above mentioned LED lighting using one or more Light Emitting Diodes (LEDs) in the tip of the endoscope, as e.g. mentioned in commonly-owned <CIT>, disclosing a disposable endoscope.

When, as according to the present disclosure, the insertion tube of the endoscope is intended to be inserted into a human body cavity, the insertion tube needs to be sealed in a watertight manner. This is in particular the case for the distal tip part because it accommodates the camera, LED(s) and other delicate electronics, prone to malfunction or destruction if exposed to humidity. Also, there are electrical requirements to ensure that the electrical insulation of the endoscope is not compromised e.g. by electrical breakdown of the polymer material from which disposable endoscopes are typically made.

Furthermore, it is desirable to provide the front window of the tip part with shading members through two-stage two-component injection moulding of a transparent window material and an opaque shading material. This is to minimize glare from the built-in light sources to the camera of the insertion endoscope. One such tip part and manufacturing method is known from commonly-owned <CIT>.

While the tip housing in accordance with <CIT> has shown to generally fulfil the above requirements, the joining of the two materials is not always optimal, inter alia because the interface between the transparent part, as seen from the distal end surface of the tip part, is formed only within the essentially cylindrical side wall of the housing away from the end wall, so that the area of the interface where the two materials bond together corresponds to the relatively thin housing side wall. This may have the effect that the electrical insulation becomes substandard, in turn leading to rejects during subsequent testing of the endoscopes, in turn, causing unnecessary costs. It furthermore, provides only a limited area for the two materials to fuse together and provide the necessary mechanical strength between the materials.

Based on this prior art it is an object of the invention to provide an endoscope, as set out in claim <NUM>, with an improved housing for the tip part which does not suffer from the above drawbacks, and a manufacturing method of said endoscope according to claim <NUM>.

According to a first aspect of the disclosure, this object is achieved by an endoscope with a distal tip part comprising a tip housing integrally moulded from a first material and a second material that is transparent. The tip housing has an end wall formed from the first material and the second material, and in the end wall the second material at least in part overlaps the first material. The tip housing can be moulded in a two step injection moulding process that yields a one-piece integrally moulded part.

In some embodiments, said housing comprises the end wall and a surrounding side wall with an internal end wall surface and an internal side wall surface so as to define at least one inner compartment accommodating an electronic vision device and at least one light source, where the end wall comprises an external end surface facing the exterior of the housing and the surrounding side wall comprises an external surrounding side surface facing the exterior of the housing, where the second material is provided as a part of the end wall so as to provide a vision window in the end wall covering the electronic vision device and a light emission window adapted to receive and transmit light from the at least one light source through the end wall, wherein, in the end wall, said second material overlaps at least partially said first material when viewed from the exterior towards the external end surface.

By creating such an overlap, the area over which the first and second materials contact each other and fuse together is increased, thus better ensuring proper fusion of the two materials. Furthermore, the distance along the fusion seam from the inside to the outside is increased, in turn, leading to a longer electrical paths, should defects in the fusion exist, hence further decreasing the risk of electrical breakdown.

According to a second aspect of the disclosure the object is achieved by a method in manufacturing an endoscope according to any one of the preceding claims wherein the tip is injection moulded in a two-stage injection moulding process in which, in the first stage, the first material is injected into a mould through a first single gate and in which, in the second stage said second material overlap is injected through a second single gate. Such method allows a cost-efficient way of manufacturing in particular the tip part of the endoscope.

According to a third aspect of the disclosure, the object is achieved by a system comprising a display device and an endoscope according to the first aspect of the disclosure connectable to the display device. In such a system the use of an endoscope according to the first aspect reduces the risk of electrical breakdown induced via the electrical connection between the endoscope and display device.

According to an embodiment of the first aspect of the disclosure, the second material is provided as one contiguous part so as to provide both said vision window and said light emission window. This allows the injection of the transparent material through a single gate only, during the injection moulding process.

According to an embodiment according to the first aspect of the disclosure, the second material is provided as one contiguous part providing part of the side wall and part of the end wall. This allows the moulding gate of the mould to be placed at a location away from front window so as to minimize any disturbance of the optical properties that may be caused by the moulding process.

According to an embodiment according to the first aspect of the disclosure, the overlap is formed as a step between the first and second materials. Using a step further increase the distance from the inside to the outside along the fusion seam and may provide large interface areas where the first and second material fuse together.

According to another embodiment according to the first aspect of the disclosure, the step comprises a first interface extending below and in parallel with the end surface. Having the interface extending below the end surface, increases the mechanical resistance of the fusion seam as the main forces acting on the end surface during insertion of the endoscope will be perpendicular to the interface.

According to a further embodiment of the first aspect of the disclosure, the step comprises a second interface extending essentially at a right angle to said first interface. This increased the area of the overall interface between the first and second material and further strengthens the fusion seam against shear forces.

According to a further embodiment of the first aspect of the disclosure, said overlap is arranged at a central part of the end surface away from the surrounding side wall when viewed from said end surface. This allows the enlarged interface are to be located in a place where it does not disturb other features, and hence allows for a relatively large and strong interface between the first and second materials.

According to a further embodiment according to the first aspect of the disclosure, the second material overlaps a moulding artefact in the first material. Thereby, moulding artefacts, such as defects and remnants from the gate of the first molding stage may be covered, in turn, providing the end wall with a smooth surface on which nothing may get caught and which is better at repelling residue that may block the vision or illumination.

According to yet another embodiment according to the first aspect of the disclosure, the tip is injection moulded in a two-stage injection moulding process in which, in the first stage, the first material is injected into a mould through a first single gate and in which, in the second stage said second material overlap is injected through a second single gate.

According to yet a further embodiment according to the first aspect of the disclosure, the second gate is arranged in conjunction with the side surface of the tip housing. That is to say at a location on the side surface, so that any residue from broken off runners at the gate will end be present on the side surface. This allows proper flow of the second material from the second gate into the front window part and the light guides which are preferably arranged mirror-symmetrical on either side of the central vision window, ensuring good filling and hence good optical properties, inter alia by keeping the single gate away from the front window surfaces.

According to still another preferred embodiment, the first gate is arranged in conjunction with the interface. That is to say at a location in the interface, so that any residue from broken off runners at the gate will end be present in the interface rather than on the outer surface of the housing. This allows central filling and good flow from a single gate that may later be covered by the second material injected elsewhere.

According to a fourth aspect of the disclosure, a method of making an endoscope is provided, the method comprising: injection moulding a tip housing comprising, after said injection moulding, an end wall and a surrounding side wall so as to define at least one inner compartment configured to accommodate an electronic vision device and at least one light source, the end wall comprising an end surface and the surrounding side wall comprising a side surface, the end wall and the side wall integrally moulded from a first material and a second material, the second material being a transparent material, wherein said injection moulding comprises, in a first stage, injecting the first material into a mould through a first single gate and, in a second stage, injecting the second material through a second single gate, and wherein, in the end wall, the second material overlaps at least partially the first material when viewed from the end surface.

The disclosure will now be made in greater detail based on non-limiting exemplary embodiments and with reference to the drawings on which:.

The present disclosure may be further understood with reference to the following description and appended drawings, wherein like elements are referred to with the same reference numerals.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Preferred methods and materials are illustrated below, although apparatuses, methods, and materials similar or equivalent to those illustrated herein may be used in practice or testing. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

The terms "comprise(s)," "include(s)," "having," "has," "can," "contain(s)," and variants thereof, as used herein, are intended to be open-ended transitional terms that do not preclude the possibility of additional acts or structures. By contrast, the term "consists," as used herein, is intended to be a closed-ended transitional term that precludes the possibility of additional acts or structures.

The term "distal," as used herein, refers to a direction or position that is generally towards a target site, and the term "proximal," as used herein, refers to a direction or position that is generally away from the target site.

Turning first to <FIG>, a visualization system <NUM> comprising an endoscope <NUM> according to the disclosure and a display device or video processing apparatus (VPA) <NUM> is shown. The endoscope <NUM> is connected to the display device <NUM> via a communications connection, which in the illustrated example is a cable <NUM>. The cable <NUM> may also include power supply for the electronics in the endoscope <NUM> as well as channels for irrigation and suction etc. thus constituting what is commonly referred to as an umbilical.

The endoscope <NUM> in the illustrated example comprises a proximal handle <NUM> adapted to be gripped by a hand of an operator. From the handle <NUM> an insertion cord <NUM> extends towards the distal end of the endoscope <NUM>. The insertion cord <NUM> comprises an insertion tube 6a and a bending section 6b extending therefrom. At the distal end of the endoscope <NUM> the insertion cord <NUM> includes a tip housing <NUM>, typically constituting the most distal end of the endoscope <NUM>. The focus of the present disclosure is on the tip housing <NUM>, as illustrated in the subsequent figures, and the skilled person will understand that the remainder of the endoscope <NUM> may have a different design without deviating from the essence of the disclosure.

In one variation, shown in <FIG>, a VPA 3a includes a housing 3b, a receptacle 3c to receive a connector of the cable <NUM>, and a handle 3d that also functions as a table stand when the monitor is positioned on a table or other support structure. The housing encloses in part a display screen 3e and circuitry operable to configure the live video captured by the image sensor of the camera module of the endoscope <NUM> to the requirements of the display screeen. The circuitry also generates a graphical user interface configured to enable the operator to control the image or video capture and presentation functions, as is known in the art.

In another variation, shown in <FIG>, a VPA <NUM> includes a housing <NUM> and a receptacle (not shown) to receive the connector of the cable <NUM> but does not include a display screen. The housing, in this variation, includes an optional display support interface 3i, which supports a display device 3j, having the display screen 3e, via a support arm <NUM>. The display device can be separated or removed from the monitor.

Both variations of the VPA may perform the same video processing functions. The processed video can be presented with a separate display device communicatively connected, via a wired or wireless connection, with the VPA <NUM>, 3a, <NUM>. This enables placement of the display screen in a location distinct from the location of the VPA <NUM>, 3a, <NUM>. This also enables use of a display device available in the operating room for other purposes.

A position interface functions to control the position of the insertion cord <NUM>. The handle <NUM> is an example of a position interface and, unless stated otherwise, the terms are used interchangeably. The handle also functions to provide manual control actuators, e.g. knobs, levers, buttons, and the like, to steer the housing <NUM> and control instruments guided through the insertion cord. Alternatively, a different position interface can be provided that is connected to the insertion cord and is detachably connected to a robotic arm. The insertion cord thus extends from the robotic arm, and the endoscope is thus detachable from the robotic arm. The housing <NUM> is the same regardless of the position interface used. The robotic arm responds to signals, such as voice commands from the operator, to rotate, translate, and otherwise position the proximal end of the insertion cord, as an operator would do manually. The position interface can include control actuators, including manual control actuators. Alternatively or additionally, control actuators can be provided in or on the robotic arm or by the robotic system including the robotic arm, thereby potentially reducing the cost of the endoscope. Example control actuators include single axis actuators, including linear motion actuators. A linear motion actuator may comprise a threaded rod coupled to a threaded nut portion, in which a motor rotates the rod to translate the nut portion.

In <FIG> the tip housing <NUM> is shown in greater detail. The tip housing <NUM> is integrally moulded from a first material and a second material, so as to comprise a first housing part <NUM> and a second housing part <NUM>. The second material forming the second housing part <NUM> is a transparent material. The first material forming the first housing part on the other hand is coloured or preferably opaque. The first and second materials are preferably polymer materials and suitable for injection moulding. The polymer of the first and second materials may be the same, i.e. the materials differing only in the filler, such as carbon black, coloured dye or lack of same.

The housing <NUM> comprises an end wall <NUM> and a surrounding side wall <NUM> so as to define at least one inner compartment <NUM>, best seen in <FIG> and <FIG>. The inner compartment accommodates an electronic vision device and at least one light source, not shown. The end wall <NUM> comprises an external end surface and the surrounding side wall <NUM> comprises an external surrounding side surface, forming the exterior surface of the housing <NUM>.

As can best be seen from <FIG>, the second material is provided as one contiguous part providing part of the side wall <NUM> and part of the end wall <NUM> so as to provide a vision window <NUM> in the end wall traversing the optical axis of the electronic device (not shown) and at least one light emission window <NUM> positioned distally of the at least one light source. In the illustrated example there are two light emission windows <NUM> arranged mirror-symmetrically on either side of the vision window <NUM>. The light emission windows <NUM>, may each comprise a light guide <NUM> adapted to receive and transmit light from the at least one light source (not shown) through the end wall <NUM>. The light guides <NUM> are adapted to shape the light emitted from the light sources in order to provide a desired light distribution withing the field of view of the endoscope <NUM>, e.g. as described in <CIT>, incorporated herein by reference.

The end wall <NUM> may comprise additional features provided with the first housing part <NUM> such as a spray nozzle <NUM> and a working channel exit port <NUM> where the spray nozzle is adapted to spray water onto the vision window <NUM> and/or the light emission windows <NUM>.

Towards the proximal end of the housing <NUM> the first housing part <NUM> may have a slightly recessed portion <NUM> to allow the bending section <NUM> to overlap the housing <NUM> and form a good connection when assembling the endoscope <NUM>. On top of both the housing <NUM> and the bending section <NUM> an outer sleeve or covering is normally fitted, in order to avoid undesired fluid ingress into the bending section <NUM>, which is normally a relatively open articulated structure.

Turning now to <FIG> details of the first housing part <NUM> as it would appear after a first moulding stage, i.e. before the second material is added in a second moulding stage, can better be seen. Since the first material is preferably opaque, apertures <NUM> allowing the light from the light sources within the housing <NUM> are provided in the end wall <NUM>. These apertures <NUM> will be covered by the light emission windows <NUM> when in the second moulding stage. The apertures <NUM> have a cross-sectional area and a circumference allowing for the accommodation of the light guides <NUM>, if provided, e.g. as an integral part of the light emission window <NUM>. As can be seen the end wall comprises a transition section <NUM> through the end wall so that the light emission window area at the end surface is larger than the cross-sectional area of the aperture deeper within the end wall <NUM>. This could be provided by flaring the walls of the aperture <NUM> out, but preferably this is done in a stepwise manner as illustrated. This provides plane surfaces <NUM> forming a first interface between the first and second materials within the end wall <NUM> of the final housing <NUM> after the second moulding step, so as to provide an increased adhesion or fusion area between the first material and the second material. The plane surfaces <NUM> are preferably arranged so that they are parallel with the final end surface <NUM> of the finished housing <NUM>, thus also providing good manual support for the light emission windows <NUM>. In other words the windows formed from the second material are provided with an undercut supported by the first material. Furthermore, the distance from the end surface outside the end wall <NUM> to the interior of the housing along the fusion seam through the wall, becomes greater than if the fusion seam was straight through the end surface perpendicular to the surface. In other words, the first interface between the first material and the second material becomes larger because of the overlap. Should defects exist the path for ingress of fluids and electrical breakdown along the fusion seam will be longer, and the risk of fluid penetration through the end wall and the risk of electrical breakdown accordingly reduced.

Similarly, i.e. for the same reasons, the passage <NUM> for light into the vision device may also be widened towards the end surface <NUM>, preferably also in a stepwise manner providing an essentially plane surface <NUM> adjacent the through passage <NUM>. The plane surface <NUM> is preferably also arranged to be parallel to the final end surface <NUM> of the finished housing <NUM>. Furthermore, the plane surface <NUM> may be at least partially surrounded by a wall <NUM> perpendicular to the plane surface <NUM>, hence forming the riser of the step. This surrounding wall <NUM> forms a second interface further increases the area and thus the mechanical strength of the overall interface between the first and second materials, in particular against shear forces.

As can be seen the essentially plane surface <NUM> may comprise a defect in the form of remnants <NUM> of the gate <NUM> (cf. <FIG>) for the polymer material into the mould cavity in the first moulding step. This allows the first housing part <NUM> to be moulded using only a single gate <NUM>, the remnants of which may then be covered to provide a smooth end surface.

The contiguous transparent material may also form part of the side wall, overlapping in a similar stepwise manner a preferably curved surface <NUM> forming a further interface between the first and second materials.

As will be further explained below and seen from <FIG> the transparent second housing part <NUM> may also be moulded using a single gate <NUM> only. This gate <NUM> may be provided in the side wall <NUM> where defects from the gate <NUM> will not have any influence on the optical transmission properties of the light emission windows <NUM> and the vision window <NUM>. Also, here a step may be provided in the wall <NUM> so as to provide a concentric surface <NUM> to support the second material and to increase the length of the fusion seam.

Turning now to <FIG>, a longitudinal section through a first mould configuration for the first moulding stage is shown with the moulded first housing part <NUM> (not in section) placed in the mould cavity for illustration. Similarly, in <FIG> a longitudinal section of a second mould configuration for the second moulding stage is shown with the finished moulded housing <NUM> (not in section) placed in the mould cavity for illustration.

In <FIG> a first mould configuration comprising two separable halves <NUM>, 27a forming a fist mould cavity corresponding to the first housing part <NUM>, is shown. The first mould half <NUM> has a central convex shape that protruded into the cavity of the second half 27a so as to provide the interior volume of the first housing part <NUM> when moulded in the first stage of a two-stage two component injection moulding process. The first material is preferably injected through a single gate arranged close to a centre axis of the first housing part <NUM>. <FIG> is schematical and details of sprues and runners leading to the gates or inlets of the mould cavity are not shown. When the first material has set the two halves are separated, preferably with the already set first material preferably remaining stuck in the first half <NUM>. A new second mould configuration shown in <FIG> may then be provided by substituting the second mould part 27a with new second half 27b corresponding to the desired final shape of the housing <NUM>. Remaining stuck in the first half <NUM>, the already set first part thus fills the reconfigured moulding cavity partially, leaving only room for the second material to provide the transparent second housing part <NUM> with the transparent windows <NUM>, <NUM> of the final housing <NUM>. The second material may then be injected via a single gate so as to form a single contiguous part. This may be done with increased pressure so that the first material properly contacts the inner wall of the second mould part 27a and provides windows <NUM>, <NUM> with no undesired defects. When the second material set the finished housing <NUM> may be removed from the mould.

Claim 1:
An endoscope with a distal tip part comprising a tip housing integrally moulded from a first material and a second material, the second material being a transparent material,
said housing comprising an end wall and a surrounding side wall with an internal end wall surface and an internal side wall surface so as to define at least one inner compartment accommodating an electronic vision device and at least one light source,
where the end wall comprises an external end surface facing the exterior of the housing and the surrounding side wall comprises an external surrounding side surface facing the exterior of the housing,
where the second material is provided as a part of the end wall so as to provide a vision window in the end wall covering the electronic vision device and a light emission window adapted to receive and transmit light from the at least one light source through the end wall,
wherein, in the end wall, said second material overlaps at least partially said first material when viewed from the exterior towards the external end surface
wherein the second material is provided as one contiguous part so as to provide both said vision window and said light emission window, and
wherein the second material is provided as one contiguous part providing part of the side wall and part of the end wall.