Patent ID: 12245752

DETAILED DESCRIPTION

Referring first toFIG.1A, an endoscope1is shown. The endoscope is disposable, and not intended to be cleaned and reused. The endoscope1comprises an elongated insertion tube3. The insertion tube3is suitable for insertion into a lung of a body through a mouth. The body can be an artificial or natural body, for instance a human or animal body. At the proximal end3aof the insertion tube3an operating handle2is arranged. The operating handle2has a control lever21for manoeuvring an articulated tip part5at the distal end3bof the insertion tube3by means of a steering wire31arunning through a flexible tube9. A camera assembly8is positioned in the tip part5and is configured to transmit an image signal through a monitor cable13of the endoscope1to a monitor11.

InFIG.1B, a monitor11is shown. The monitor11allows an operator to view an image captured by the camera assembly8of the endoscope1. The monitor11comprises a cable socket12to which a monitor cable13of the endoscope1can be connected to establish a signal communication between the camera assembly8of the endoscope1and the monitor11.

Turning toFIG.2A, the distal end3bof the insertion tube3is shown and more specifically the articulated tip part5. The tip part5comprises a bending section4, and an exterior housing part6. The bending section4comprises a number of hingedly connected segments including a proximal end segment43, a distal end segment41, and a plurality of intermediate segments42positioned between the proximal end segment43and the distal end segment41. In the present embodiment, the number of intermediate segments42is about32, but may in principle be less or even greater. Three hinge members44of the living hinge type interconnects each pair of adjacent segments. The hinge members44bridge a gap between adjacent segments. The bending section4allows the tip part5to bend relative to the flexible tube (omitted in this figure), so as to allow an operator to manipulate the tip part5while inserted into a body cavity. The bending section4and each hingedly interconnected segment41,42,43consist essentially of the same material and are integrally formed in one piece. The material is polyoxymethylene (POM) but may be any suitable material, such as polyethylene (PE) or polypropylene (PP). Typically, a tubular sleeve8for providing a smooth outer surface wraps around the bending section4but the tubular sleeve8is omitted in the figure for visualisation purposes. The tip part5further comprises a working passage33connected with a working tube34(shown foreshortened in length for visualisation purposes) to provide a working channel. The attachment surface72extends partially around the circumference of the tip part5and the working channel tube34may form the remaining extent so that the attachment surface72and the working channel tube34together form a surface extending around the entire circumference as best seen inFIG.5C.

As seen inFIGS.2B and3B, the exterior housing part6includes a proximal opening6dand proximal rim surface6e; a circumferentially extending side wall6awith an exterior surface6band an interior surface6genclosing an interior space6hconfigured for accommodating the camera assembly8; and a distal end wall61with an image sensor window61aand a first61band a second light guide61cas seen inFIGS.3A,3B, and4C. The distal end wall61forms the distal end3bof the tip part5.

As seen inFIG.3C, the camera assembly8is positioned at a distal end3bof the tip part5in the interior spacing6hof the exterior housing part6so that an image sensor83is viewing out through a window61aof the distal end wall61to allow an operator to inspect a distal body cavity when the insertion tube3is inserted into the body cavity. The camera assembly8comprises an image sensor83configured to capture an image, at least one lens with a light receival surface83aconfigured to alter light received by the image sensor83, a holder85for supporting the parts of the camera assembly8, a first81and a second light source82configured to provide illumination for the image sensor83, which in this embodiments is in the form of light emitting diodes, a printed circuit board84, cables87(shown foreshortened in length for visualisation purposes) configured for carrying an image signal from the printed circuit board84to the monitor11and for supplying power to the printed circuit board84. The cables87are accommodated in a cable tube32a(shown foreshortened in length for visualisation purposes) and are electrically connected to the printed circuit board84. The printed circuit board84is configured to process a signal from the image sensor83and transmit the signal via cables87configured to transmit signals to the monitor cable13of the handle2for output to a monitor11. The printed circuit board84includes a flexible folded connection84a,84bbetween each of the light sources81,82and the image sensor83so that the light sources81,82can be individually moved axially further from or closer to the image sensor83.

As can be seen inFIGS.3B and3C, the tip part5further comprises an interior housing part7with a first tolerance compensating member73, a second tolerance compensating member74, a closure surface71, and an attachment surface72. The closure surface71extends circumferentially around a cavity76and coaxially and parallel with the proximal-distal axis PD so that, when the interior housing part7is positioned in the interior space6h, a substantially uniform gap of about 20-50 micrometres is formed between closure surface71and the interior surface6gas can be seen inFIG.5B. The closure surface has an axial extent of about 1.1 mm. The interior housing part7further comprises a cable tube hole75forming a proximal access way into the cavity76. The interior housing is prefabricated in one piece in an ultraviolet (UV) translucent or UV transparent material.

The first73and second tolerance compensating member74each has a distally positioned seat73b,74bconfigured for accommodating the respective light source81,82and an arm73a,74aconnecting said seat73b,74bwith the closure surface71. The interior housing part7narrows from the closure surface71to the attachment surface72which is positioned proximally in relation to the closure surface71. The attachment surface72includes cut-outs72ain the form of nine grooves for improving the mechanical connection to the distal end segment41of the bending section4, but the number of grooves could in principle be more or less depending on specifics.

In another embodiment as shown inFIGS.4A,4B, and4C, the first81and second light sources82are instead in the form of light fibres (shown foreshortened). Each light fibre has a distal end with a light emitting surface81a,82a, which in the post-compensation and assembled condition, abuts the respective second63and third stop surface64of the window61a. The light fibres are typically not electrically connected to the printed circuit board84and the seat73b,74bof the tolerance compensating members73,74can be omitted. Instead each light fibre81,82extend along the respective arm73a,74aof the tolerance compensating member73,74and are typically held and sealed by a mechanical connection, such as an adhesive connection, with the arm73a,74a, but a friction engagement could be applied additionally or alternatively to adhesive in order to maintain the position of each light fibre relative to the respective arm73a,74a.

The following describes the method of bringing the tip part5from a pre-compensation condition as shown inFIGS.2B and3B, onto a post-compensation condition as can be seen inFIGS.3C and4C, and further to an assembled condition as shown inFIGS.2A and5A-5C. Firstly, a camera assembly8is provided as described above, then cables87of the camera assembly8are inserted into the cable tube hole75from the distal direction to arrive at the arrangement shown inFIGS.2B,3B, and4A. The camera assembly8is then guided into the interior housing part7so that a proximal portion of the holder85is positioned in the cavity76, the first81and second light source82are positioned in and fixed to the respective first73band second seat74bas shown inFIG.3C, alternatively the light sources81,82extend along and maintained in position by the mechanical connection with the arms73a,74aas shown inFIG.4C. An upstanding guide portion85aof the holder85centers the camera assembly8in the cavity76. Simultaneously or alternatively afterwards, the cable tube32ais positioned in the cable tube hole75wrapping around the cables87of the camera assembly8. The interface32bbetween the cable tube hole75and the cable tube32a, as best seen inFIG.5C, is then sealed by an adhesive.

Thirdly, an exterior housing part6is provided. The exterior housing part6comprises a circumferentially extending side wall6awith a distal end wall61and a proximal rim surface6edefining a proximal opening6d. The circumferentially extending side wall6ahas an outer surface6band an interior surface6g. The exterior housing part6adefines an interior space6hwith a distal air volume6i. The distal end wall61includes a window61awith a first stop surface62, a first light guide61bwith a second stop surface63, and a second light guide61cwith a third stop surface64. In this stage of the assembly method, the exterior housing part6could be interchanged with an assembly fixture instead.

Fourthly, the camera assembly8is then positioned so that the light receival surface83ais in contact with the first stop surface62. At this point, depending on dimensions and tolerances of the parts, either none, one, or both of the light emitting surfaces81a,82aof the light sources81,82are in contact with their respective second63and third stop surface64. To ensure that both the light sources81,82are in contact with their respective stop surfaces63,64, the interior housing part7is urged in position by an operator pushing the attachment surface72distally so that the seats73b,74bof the tolerance compensating members73,74or the mechanical connection between the arms73a,74aand the light sources81,82pushes the respective light source81,82in their respective optical axis81b,82binto contact with the respective stop surface63,64thereby arriving at the post-compensation condition of the tip part5as can be seen inFIGS.3C or4C.

Fifthly, either the interior housing part7is fixed to the exterior housing part6or, in the case of using the assembly fixture, the interior housing part7is fixed to the camera assembly8, for instance to the holder85.

The interior housing part7is fixed to the exterior housing part6by injecting an UV curable adhesive in the gap52between the closure surface71and the interior surface6gof the exterior housing part6as best seen inFIGS.5A and5B(omitting the bending section4for now). A capillary effect then draws the adhesive into the gap52while ensuring that the adhesive does not flow out from the distal end of the gap52and ensures that the adhesive is distributed around the circumference. Once the adhesive is sufficiently distributed, the adhesive is caused to harden by exposure to UV light which propagates through the UV translucent material of the interior housing part7. In this case, the light sources are in the correct position with minimal air gap between the light emitting surfaces81a,82aand the respective stop surface63,64. Furthermore, the air volume around the light sources81,82are liquid-sealed ensuring that the optical properties are not altered by ingressing liquids.

In the case of assembly using the assembly fixture, the interior housing part7is fixed to the holder85by injecting adhesive in a gap between the guide portion85aof the holder85and an interior surface of the interior housing part7opposite the closure surface71, and thereafter causing the adhesive to harden by exposure to UV light. The combined interior housing7and camera assembly8can then be fitted into an exterior housing by the above method. In this case, any air gap between the light emitting surfaces81a,82aand the respective stop surface63,64depends on the tolerances of the injection moulded exterior housing part6and the assembly fixture which can be manufactured with relatively tight tolerances.

Sixthly, as can be seen inFIG.5C, the distal end segment41of the bending section4is positioned adjacent to and overlapping with the attachment surface72of the interior housing part7. Adhesive is then injected through holes41gso that the adhesive fills said holes41gand the grooves72aof the attachment surface72and further wets the interior surface41fof the distal end segment41to fix the interior housing part7, and thereby the exterior housing part6and camera assembly8, to the bending section4to arrive at the assembled condition of the tip part5.

LIST OF REFERENCES

The following is a list of reference numerals used throughout this disclosure. In case of any doubt, the reference numerals of the following list apply.1endoscope11monitor12cable socket13monitor cable2handle21control lever3insertion tube3aproximal end3bdistal end32acable tube32binterface33working passage34working tube4bending section41distal end segment41adistal end41finterior surface41ghole42intermediate segment43proximal end segment44hinge member5tip part52gap6exterior housing part6acircumferentially extending side wall6bouter surface6dproximal opening6eproximal rim surface6ginterior surface6hinterior space6iair volume61distal end wall61awindow61bfirst light guide61csecond light guide62first stop surface63second stop surface64third stop surface7interior housing part71closure surface72attachment surface72agroove73first tolerance compensating member73aarm73bseat74second tolerance compensating member74aarm74bseat75cable tube hole76cavity8camera assembly81first light source81afirst light emitting surface81boptical axis82second light source82asecond light emitting surface82boptical axis83image sensor83alight receival surface84printed circuit board84afolded connection84bfolded connection85holder85aguiding portion86lens barrel87cable9flexible tubePD proximal-distal axis