Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
  • A61B1/06—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements
  • A61B1/07—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements using light-conductive means, e.g. optical fibres
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
  • A61B1/00064—Constructional details of the endoscope body
  • A61B1/00071—Insertion part of the endoscope body
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
  • A61B1/00163—Optical arrangements
  • A61B1/00165—Optical arrangements with light-conductive means, e.g. fibre optics

Definitions

• the present invention relates to endoscopes and in particular, though not exclusively, to an improved endoscope which is relatively inexpensive to manufacture but which can withstand sterilisation so as to enable it to be reused.
• endoscopes There are generally two types of endoscopes: rigid endoscopes and flexible endoscopes.
• Flexible endoscopes use a flexible optical fibre bundle to relay an image from a distal end (often referred to as the "objective end") of the device to an ocular section which magnifies the image for viewing by an operator.
• some flexible endoscopes use small cameras at the distal end and transmit the image along electrical wires to the ocular section.
• Rigid endoscopes use lenses to transmit the image, instead of optical fibres.
• rigid endoscopes generally provide better resolution and brightness than fibres and for this reason rigid endoscopes are preferred for many medical procedures where image quality is crucial.
• rigid endoscopes also incorporate an optical fibre bundle for transmitting light from the ocular end of the device to the area under observation at the objective end.
• the fibres are generally disposed in a circular arrangement surrounding the lenses, the fibres and lenses all being contained within an outer casing of the endoscope.
• endoscopes it is generally desirable for endoscopes to be reusable but rigid endoscopes are difficult to sterilise as their various component parts, such as casing, lenses, fibre bundles and connectors, are generally made of different materials such as steel, glass and plastics, not all of which are capable of withstanding the rigours of normal hospital sterilisation processes such as autoclaving. Many rigid endoscopes are therefore easily damaged if subjected to autoclaving. Autoclaving may damage the optical fibre bundle and/or the lens set and/or adhesive used in either of these features. Thus some rigid endoscopes have been designed to be disposable, or at least partially disposable.
• US 5,396,366 describes an improved rigid endoscope design in which, instead of using a fibre bundle to transmit light to the objective end, the lenses are surrounded by a light transmitting tube made of acrylic or similar material. A beam of light is directed into the solid body of the light transmitting tube in order to illuminate the area under observation at the objective end of the device. An outer steel casing surrounds the acrylic tube to protect and support it during use. The lenses and the light transmitting tube are provided in a disposable objective section which is designed to be detachable from a reusable ocular section of the endoscope.
• One problem of trying to mould a hollow tube from plastics is that a rod of some sort would have to be inserted into the mould cavity in order to create the central cylindrical void of the tube.
• some light travelling up the axial cavity, from the objective end to the ocular end of the device, may be reflected off the interior surface of the light transmitting tube. Again, this may interfere with or otherwise detrimentally affect the image being relayed to the ocular end.
• an endoscope body comprising a probe portion and an ocular portion, the probe portion comprising an elongate light guiding member having an axial cavity extending therethrough for containing at least one lens, wherein the axial cavity is lined with a layer of material which substantially prevents light from leaking into the axial cavity from the light guiding member.
• the layer of material may be reflective to light travelling out of the light guiding member towards the axial cavity. Alternatively, or additionally, the layer of material may be absorptive to light travelling out of the light guiding member towards the axial cavity.
• the layer of material may be made of an opaque material, or of a metal.
• the layer of material may also be absorptive to light within the axial cavity or, alternatively, the layer of material may have a further layer of opaque material deposited thereon, whereby reflection of light within the axial cavity is substantially avoided.
• the probe portion and the ocular portion of the endoscope body may be formed as a single moulding.
• the light guiding member may comprise a body portion in the form of a hollow light pipe. An inner surface of the hollow light pipe may be coated, plated or otherwise covered with the layer of material which substantially prevents light from leaking into the axial cavity from the light guiding member.
• the light pipe is preferably made of a substantially rigid moulded plastics material.
• the layer of material is in the form of an elongate tube to an outer surface of which the elongate light guiding member is preferably moulded directly.
• the elongate tube is preferably substantially rigid, whereby the endoscope is also substantially rigid.
• the tube may be made of titanium, steel or another strong metal.
• the metal tube has the advantage of stiffening the endoscope, improving its strength and preventing distortion during and after autoclave sterilisation.
• the tube may be made of an extruded material (e.g. extruded aluminium, ceramic, carbon fibre or plastics material) .
• the extruded tube has a greater stiffness than the light guiding member it will improve the overall rigidity and strength of the endoscope.
• One or more lenses may conveniently be contained within the metal (or extruded plastics) tube, in use of the endoscope body.
• the tube is made of metal the interior surface of the tube is preferably anodised or otherwise coated or treated so as to substantially avoid reflection of light within the metal tube.
• the metal tube provides a generally light-tight receptacle for the one or more lenses to be contained within the axial cavity.
• a plastics body having a cylindrical axial cavity to house the lenses.
• the light guiding member again preferably comprises a body portion in the form of a hollow light pipe.
• the elongate light guiding member is preferably made of moulded plastics material which is transparent or translucent.
• the light pipe preferably surrounds the elongate tube along a substantial portion of the length of the tube and is moulded directly to an exterior surface of the elongate tube.
• the light guiding member may further include a beam directing end portion which is preferably integrally formed with said body portion and which extends into the ocular portion of the endoscope, this end portion being formed and arranged for guiding light into the light pipe, for example from an input light source optically coupled to said end portion in use of the endoscope.
• An output end of the light pipe preferably terminates proximal to, or flush with, a distal end of the elongate tube.
• Light can thus be transmitted, via the light guiding member, from a light source, down the endoscope, to the output end of the light pipe from where it exits to illuminate an area to be examined.
• the exterior surface of the hollow light pipe may be coated with a light-reflective material. This improves internal reflection in the light pipe whereby transmission losses in the light pipe are reduced.
• the light pipe may be coated with a transparent or translucent material having a different refractive index to the material of the light pipe, the different refractive indices being chosen so as to improve the internal reflection characteristics (and therefore the light guiding characteristics) of the light pipe whereby transmission losses in the light pipe are reduced.
• a reflective or transparent/translucent coating may also have the benefit of providing a degree of physical protection to the light pipe.
• the ocular portion of the endoscope is preferably made of moulded plastics material.
• the ocular portion of the endoscope may conveniently comprise an ocular end which is moulded to a proximal end of the elongate tube, and preferably also includes a further portion which is over moulded to the beam directing end portion of the light guiding member.
• This over moulded portion or, alternatively, the beam directing input end portion of the light guiding member may conveniently be formed and arranged for enabling an industry standard input lightguide or light source, or an adaptor for connection thereto, to be connected directly to the over moulded portion or the input end portion respectively, so as to optically couple a light guide or light source to said beam directing end portion of the light guiding member.
• the ocular end may conveniently include an eyepiece which forms a proximal end of the endoscope and is formed and arranged for enabling a person to view with one eye the magnified image of the area being examined.
• the over moulded portion of the ocular portion and/or the beam directing end portion of the light guiding member may be provided, integrally or otherwise, with protection means for protecting the ocular portion (and the input end of the light guiding member which extends there into) from the effects of heat or laser damage whilst the endoscope is in use. Such damage may otherwise be caused by the input light, which may for example be a laser beam, coupled to the endoscope in use thereof.
• the protection means may, for example, comprise a metallic or ceramic adaptor via which the input light source is connected to the endoscope.
• an endoscope comprising the endoscope body according to the first aspect of the invention, and further including at least one lens, preferably a set of lenses, disposed within the axial cavity of the light guiding member. These lenses are formed and arranged in known manner to produce, at the ocular end of the endoscope, a magnified image of the area being examined. It will be appreciated that significant advantages of the present invention over prior art such as the device described in US 5,396,366 include the strength of the inventive device, and the fact that it incorporates the whole of the illumination path as well as much of the endoscope body.
• Fig.1(a) is a perspective view of an endoscope according to one embodiment of the invention
• Fig.1(b) is a perspective assembled view of various components housed within the endoscope of Fig.1(a)
• Fig.2 is a sectional view taken along the axis of the endoscope of Fig.l, showing the endoscope body with the components of Fig.2 removed
• Fig.3 is a sectional view, taken along the axis of the endoscope of Figs .1 and 2, of a proximal end of the endoscope, showing some of the components of Fig.1(b) inserted therein
• Fig.4 is a sectional view taken along the axis of the endoscope of
• Fig.5 is a sectional view of an endoscope body according to an alternative embodiment of the invention.
• Figs.l and 2 illustrate a rigid endoscope body according to a first embodiment of the invention.
• the endoscope 1 is formed from an inner titanium tube 2 to which two body portions made of plastics material are moulded directly.
• the first body moulding 4 has a first portion in the form of an elongate transparent light- guiding tube or "light pipe" 5 made of a polymer material which is moulded directly to and covers an exterior surface of the titanium tube 2 along the majority of the length of the titanium tube, this providing a probe portion 8 of the endoscope.
• the light-pipe is coaxial with the tube 2 and terminates flush with a distal end of the tube 2 at an objective end 7 of the endoscope.
• the first moulding includes an integral second portion 6 extending away at an angle to the axis of the light-pipe and formed and arranged to direct or guide a beam of light into the light-pipe 5.
• the proximal end 8 of the titanium tube protrudes from the first moulding 4.
• the second body moulding 10 is over moulded to the beam directing second portion 6 of the first moulding 4 and to the protruding proximal end 8 of the titanium tube and includes a bore or axial cavity 12 in optical communication with the cylindrical axial cavity 3 of the titanium tube 2 and terminates in an eyepiece 14 forming an ocular end of the endoscope.
• the overmoulding 10 surrounds the beam directing portion 6 of the first moulding and, proximal to a free end 9 of the beam directing portion 6, is configured with a screw thread 11 (or other suitable connection means) for enabling a light input device such as a laser diode or an optical fibre or fibre bundle (not shown) , to be optically coupled to the beam directing portion 6 of the first moulding.
• the first moulding 4 may protrude through the overmoulding 10 and the screw thread 11 would in that case be provided on the protruding portion of the first moulding 4.
• the eyepiece 14 may be fitted with a transparent or translucent window 15 which plugs the ocular end of the endoscope to prevent dirt or debris from entering the endoscope and contaminating a set of lenses (not shown in Fig. 2) which are housed within the cylindrical axial cavity 3 of the steel tube 2 in use of the endoscope body in a working endoscope.
• a transparent window 16 plugs the titanium tube 2 at the objective end 7 of the device 1.
• This window 16 is made of glass, or a transparent plastic or ceramic material.
• a set of lenses 18 for magnifying an image of an area being examined, and for relaying the magnified image to the ocular end, is inserted into the endoscope body 1.
• These may be plastic or glass lenses, or there may be some plastic and some glass lenses.
• the lenses are arranged in series and are configured so that they are oriented and held in coaxial relation by the titanium tube 2.
• the set of lenses will include at least one objective lens 22 at the objective end 7 of the probe portion 8, and a relay section of one or more rod lenses 20 extending along the probe portion towards the ocular end.
• One or more additional convex lenses 21 see Fig.
• Figs.1(a) and (b) show the various disassembled components of the working endoscope, before they are assembled together.
• an eyepiece lens holder 30 is provided for holding the convex magnifying lenses 21 in the ocular end.
• a spacer 32 is disposed between the eyepiece lens holder 30 and an eyepiece backing ring 34 over which an eyepiece spring 36 is disposed.
• the lens holder 30 is provided with a screw thread for engaging with a complementary screw thread provided in the interior of the ocular end of the overmoulding 10.
• Fig.3 shows the proximal end of the endoscope, with the components of Fig.1(b) mounted inside.
• the spring 36 biases the backing ring 34 towards the end of the titanium tube 2, so as to bear against and push the last one of the rod lenses 20 into the tube 2, thus holding the rod lenses 20 firmly inside the tube 2.
• the backing ring 34 includes a window 35 axially aligned with the tube 2 so as to allow the image from the relay lenses to pass through the backing ring to the ocular end.
• At the objective end there are two spacers 38, 39 disposed in series, between the objective lens 22 and the relay lens section.
• a front protective sleeve 40 may be fitted to the tip of the objective end 7 of the endoscope body and an annular front protective window 42 may be provided on the end of this sleeve 40 (these parts are indicated in Fig.1(a), not assembled to the endoscope body 1).
• Fig.4 shows the device of Figs.l to 3 with the protective sleeve 40 and window 42 fitted to it.
• the sleeve 40 is made of a stainless steel tube portion 41.
• the annular window portion 42 is made of glass, transparent plastic or ceramic and extends between the tube portion 41 and the titanium tube 2 of the endoscope body 1.
• the protective sleeve 40 and annular window portion 42 are moulded in to the light pipe 5, along with the tube 2, during manufacture of the endoscope.
• the inner tube 2 being made of metal it could be made of an extruded material such as extruded aluminium, or a non-metallic extruded material such as a plastics or carbon fibre material.
• the inner tube is made of a stiffer material than the first moulding 4 it will still have the benefit of increasing the rigidity and hence strength of the endoscope body.
• Stiffness may be further improved by providing radial fins on the outer surface of the extruded tube, for gripping into the light pipe 50 which is moulded thereto.
• a rigid light pipe 50 having a generally cylindrical axial cavity 52 extending therethrough is formed by moulding or otherwise, and the inner surface 54 of the light pipe is lined with a layer of opaque material which is coated, deposited or otherwise attached to the inner surface 54 so as to cover this surface.
• the whole of the endoscope body 1' may conveniently be moulded as a single piece, as shown in Fig.5.
• the opaque layer may, for example, be in the form of a metal coating.
• the metal coating prevents light from leaking into the axial cavity from the light guiding member (by virtue of the fact that it is very reflective to such light) .
• the opaque material may be an opaque plastics material. This has the additional benefit of largely preventing reflection of light within the axial cavity which could otherwise interfere with the relayed image. (A metal coating may not provide this additional benefit.)
• the inner surface of the light pipe may be lined with a layer of material designed to be reflective to light in the light pipe, and this reflective layer is itself covered with a layer of opaque material to substantially avoid reflections of light within the cavity.
• the outer surface of the light pipe (but not the end surfaces in the objective end 7 or the free end 9 of the beam directing portion 6) may be painted or plated with a reflective material, or may simply be left as moulded (no coating) .
• the viewing angle of the endoscope is zero degrees (i . e . "straight ahead"), it will be understood that the endoscope may easily be designed for a different viewing angle e.g. 45 degrees, 90 degrees, or 120 degrees as desired in a similar manner to known endoscopes having these viewing angles: for example, by effectively slicing the objective end at an angle, so that the window 16 is in that case disposed at an angle.

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• Health & Medical Sciences (AREA)
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• Optics & Photonics (AREA)
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• 2003
  • 2003-09-10 GB GB0321144A patent/GB0321144D0/en not_active Ceased
• 2004
  • 2004-08-26 WO PCT/GB2004/003669 patent/WO2005023099A1/en active Application Filing
  • 2004-08-26 EP EP04768224A patent/EP1662967A1/de not_active Withdrawn

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