Patent Description:
This invention relates to visualization systems in general, and more particularly to stereoscopic endoscopes which may be articulated and directed by the user.

Typically endoscopes that may be articulated are limited to single channel optical or electronic image transmission means.

Optical endoscopes that are flexible currently rely upon coherent optical fiber bundles to transmit coarsely pixilated images, giving the user the impression of viewing a scene through a grid, not unlike viewing a scene through a window screen.

Electronic endoscopes (also known as "chip-on-tip" or "chip-on-stick" endoscopes) that are flexible feature a single, highly miniaturized image sensor disposed at the distal end of the device.

Both types of endoscopes (i.e., optical and electronic) typically include fiber optic illumination means for illuminating the operative field which is being directly visualized.

Due to challenges in adequately sealing flexible and articulating endoscopes, these types of devices are limited to cold sterilization techniques.

Typically, such flexible and articulating endoscopes are hand-held and steered directly by the user.

Stereoscopic (i.e., 3D) endoscopes differ from their non-stereo counterparts in that they are more sensitive to optical misalignments. Not only must each channel be optically aligned for the best image, but also key optical parameters for each channel (such as magnification, boresight, image rotation, image focus, etc.) must be identical between the two channels - otherwise, an unwanted parallax will be created in the system, causing depth distortions and user eye strain/fatigue in converging the two images.

<CIT>, <CIT> and <CIT> each discloses a steerable endoscope with features of claim <NUM>.

The present invention addresses the forgoing issues and provides a steerable electronic stereoscopic endoscope which appropriately maintains channel alignment, and which appropriately maintains key optical parameters for each channel, so as to avoid unwanted parallax and thus minimize user eye strain/fatigue. In addition, the steerable electronic stereoscopic endoscope of the present invention is able to withstand the pressure and elevated temperatures of steam autoclave sterilization, so that the steerable electronic stereoscopic endoscope may be sterilized with both hot and cold sterilization techniques.

The invention is a steerable stereoscopic endoscope as defined in claim <NUM>. In a form of the invention, there is provided a steerable stereoscopic endoscope comprising:.

In a form of the invention, there is provided a steerable endoscope comprising:.

These and other objects and features of the present invention will be more fully disclosed by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein:.

Looking first at <FIG>, there is shown a steerable electronic stereoscopic endoscope <NUM> formed in accordance with the present invention. Endoscope <NUM> generally comprises a shaft <NUM> having a distal end <NUM> and a proximal end <NUM>. Shaft <NUM> is flexible in the articulating region <NUM> as will hereinafter be discussed in further detail. The proximal end <NUM> of shaft <NUM> is mounted to a handle <NUM>.

<FIG> shows shaft <NUM> in the articulating region <NUM>. Articulating region <NUM> generally comprises a distal joiner deck <NUM>, at least one intermediate deck <NUM> and a base joiner deck <NUM>. Further elements in the articulating region <NUM> include a central supporting Nitinol super-elastic wire <NUM> captively supported within distal joiner deck <NUM> and base joiner deck <NUM>. Intermediate deck <NUM> is slidably supported by Nitinol superelastic wire <NUM>. A plurality of stacked spacer elements (e.g., rings) <NUM> are coaxially mounted on Nitinol superelastic wire <NUM> between distal joiner deck <NUM> and the at least one intermediate deck <NUM>, and between the at least one intermediate deck <NUM> and base joiner deck <NUM>, so as to ensure a fixed spacing between distal joiner deck <NUM> and the at least one intermediate deck <NUM>, and between the at least one intermediate deck <NUM> and base joiner deck <NUM>, regardless of endoscope articulation.

Four actuating wires <NUM> (only three of which are seen in <FIG>) are bonded securely within distal joiner deck <NUM> and slidably pass through the at least one intermediate deck <NUM> and base joiner deck <NUM>.

Four conduit tubes <NUM>, joined to base joiner deck <NUM> and extending proximally therefrom, maintain straightness and proper orientation of actuating wires <NUM> as the actuating wires pass through the axial length of endoscope <NUM>.

Looking now at <FIG> and <FIG>, two metal bellows <NUM> are hermetically joined (at joints <NUM>) to their respective decks <NUM> and <NUM>, and <NUM> and <NUM>, providing rotational rigidity to endoscope <NUM> and hermetically sealing the elements within.

Holes <NUM> in decks <NUM>, <NUM> and <NUM> allow electronic leads <NUM> (see <FIG>) to slide freely within decks <NUM>, <NUM> and <NUM>, and holes <NUM> in decks <NUM>, <NUM> and <NUM> allow fiber optic illumination bundles <NUM> (see <FIG>) to slide freely within decks <NUM>, <NUM> and <NUM> during endoscope articulation.

<FIG> shows the sealed camera module <NUM> which is disposed in shaft <NUM> distal to distal joiner deck <NUM>, with electronic leads <NUM> and fiber optic illumination bundles <NUM> passing through holes <NUM> and <NUM> within decks <NUM>, <NUM> and <NUM>. Sealed camera module <NUM> comprises an outer sleeve <NUM>, an elastomer seal <NUM> and the aforementioned electronic leads <NUM> (from the camera module's image sensor assemblies, see below) and optical fiber illumination bundles <NUM>.

<FIG>, <FIG> and <FIG> show interior construction details of sealed camera module <NUM>.

<FIG> shows the module body <NUM> which is disposed coaxially within outer sleeve <NUM> of sealed camera module <NUM>, and an image sensor assembly <NUM>, as well as the aforementioned electronic leads <NUM> and fiber optic illumination bundles <NUM>.

<FIG> illustrates the interior elements of sealed camera module <NUM> aligned and bonded within module body <NUM>. Shown are pairs of CCD image sensor assemblies <NUM>, camera lens cells <NUM> and optical fiber illumination bundles <NUM> bonded and polished within ferrules <NUM>.

<FIG> illustrates the foregoing elements bonded within module body <NUM>. The pair of image sensor assemblies <NUM> are carefully optically aligned and then bonded (e.g., at <NUM>) to module body <NUM>. Note that camera lens cells <NUM>, and fiber optic illumination bundles <NUM> (mounted within ferrules <NUM>), open on the distal end of module body <NUM>. Thus it will be seen that sealed camera module <NUM> comprises a module body <NUM> which carries image sensor assemblies <NUM> and ferrules <NUM> supporting fiber optic illumination bundles <NUM>, and this module body <NUM> is secured within outer sleeve <NUM> and sealed with elastomer seat <NUM>, with the electronic leads <NUM> of image sensor assemblies <NUM> and fiber optic illumination bundles <NUM> extending through elastomer seal <NUM>.

<FIG> illustrates the assembled distal end <NUM> of endoscope <NUM>, including articulating region <NUM>. Note that the distal end of distal joiner deck <NUM> is received within outer sleeve <NUM> of sealed camera module <NUM>, with the distal end of distal joiner deck <NUM> abutting elastomer seal <NUM> and with the outer sleeve <NUM> of sealed camera module <NUM> being hermetically bonded to the outside diameter of distal joiner deck <NUM>. Note also that electronic leads <NUM> of image sensor assemblies <NUM> and fiber optic illumination bundles <NUM> extend through decks <NUM>, <NUM> and <NUM>, with metal bellows <NUM> cooperating with decks <NUM>, <NUM> and <NUM> so as to render the distal end of shaft <NUM> hermetically sealed.

<FIG> shows the endoscope's steering and brake assembly <NUM> which is contained within, and extends out of, handle <NUM>. Using steering and brake assembly <NUM>, the user may direct the viewing angle of the endoscope by manipulating the control joystick <NUM>, which comprises shaft members <NUM> and <NUM> and knob <NUM>. The control joystick position also provides an external indication of the endoscope's viewing position, with the shaft (<NUM>, <NUM>) of control joystick <NUM> representing the axis of a pointer and knob <NUM> representing the "tail" of the pointer.

Control joystick <NUM> is secured by a captive ball joint <NUM> (<FIG>) formed by a base <NUM>, a bearing ball <NUM> and a braking element <NUM>. Viewing may be directed in a <NUM> degree conic arc of up to, but not limited to, an included angle of <NUM> degrees without altering the disposition of the main body of endoscope <NUM> itself. <FIG> shows the actual device with the viewing angle being held in place by the brake feature.

Manipulating control joystick <NUM> deflects the distal end of the endoscope, whereby to appropriately direct its camera, by pulling one or more of the four actuating wires <NUM> (<FIG>) held in position within a swash plate <NUM> by four ball-ended terminations <NUM> (<FIG> and <FIG>) bonded or swaged to their respective Nitinol pull wires <NUM>.

<FIG> and <FIG> represent sectional views of the steering and brake assembly <NUM>. When the desired view position is achieved, the brake is applied by rotating knob <NUM> clockwise.

Knob <NUM> drives the brake cam <NUM> (<FIG>) through a drive pin <NUM>. A Nitinol brake pull wire <NUM> (<FIG>) passes through a threaded tubular control joystick core <NUM> and is fixed within the braking element <NUM> by two non-scoring set screws <NUM> (<FIG>). Nitinol (a superelastic nickel titanium alloy) is used for its high strength in brake pull wire <NUM> as well as in the aforementioned Nitinol superelastic wire <NUM> disposed within the distal end of the endoscope (see above). Nitinol's unique elastic properties resist fatigue and contribute to maintaining straightness when the brake is not engaged.

Braking element <NUM> (<FIG>) features a partial precision hemispherical socket covering approximately one third of the control stick precision bearing ball <NUM> (<FIG>). With the brake released, the braking element <NUM> serves as the distal element of the control stick bearing socket. The movable braking element <NUM> (<FIG>) is constrained by the main tube sleeve <NUM> (<FIG>). Proximally, the Nitinol brake pull wire <NUM> (<FIG>) is attached to the cam follower body <NUM> (<FIG>) by two non-scoring set screws <NUM> (only one of which is shown in <FIG>). Two cam follower pins <NUM> (<FIG>) are inserted through slots in the cam <NUM> (<FIG>) and restraining grooves <NUM> in the knob body <NUM> (<FIG>).

<FIG> shows, at <NUM>, the exit point of the hole through the threaded core <NUM> of control joystick <NUM> located at the center point of the bearing ball <NUM>. This is done to minimize any effective length change caused by the excursion made by the control joystick during use. Minimizing this length change effect removes unwanted friction and/or, conversely, sudden accidental brake release.

Referring to <FIG>, it will be seen that rotating the knob <NUM> clockwise will place increasing tension on the braking element <NUM> via brake pull wire <NUM>, which in turn clamps upon the control stick bearing ball <NUM> with sufficient friction to effectively hold swash plate <NUM>, and hence the distal end of the endoscope's shaft, with the desired view orientation, yet light enough to allow overriding movement of the control joystick.

Undesirable rotation of the swash plate <NUM> is prohibited by a restraining tab <NUM> (<FIG> and <FIG>) which is disposed within a parallel pair of dowel pins <NUM> joined to base <NUM>.

As shown in <FIG> and <FIG>, the effective leverage of the swash plate <NUM> when acting upon the pull wires <NUM> is maintained by the four rounded grooves <NUM> in base <NUM>.

<FIG> and <FIG> show the proximal hand control end of endoscope <NUM>. Handle <NUM> may be gripped by the user and the control joystick <NUM> operated with the thumb of the gripping hand of the user, or the control joystick <NUM> may be operated with the other hand of the user.

The fiber optic illumination bundles <NUM> are terminated and polished at <NUM> in an input connector <NUM> to which an input light guide (not shown) from the accessory light source (not shown) is connected. The electronic leads (cable) <NUM> (<FIG>) connect the image sensor assemblies <NUM> (<FIG>) to the main 3D video control unit (not shown) and are routed through (at <NUM>) a suitable strain relief <NUM>.

Both the electronic cable strain relief <NUM> and the fiber optic input connector <NUM> are sealably bonded at <NUM>, <NUM>, respectively, to handle <NUM>.

Control joystick <NUM> is movably sealed to handle <NUM> by an elastomer seal <NUM> which is configured so as to minimize resistance to movement of control joystick <NUM>. Area <NUM> of elastomer seal <NUM> is preferably made slightly undersized so as to grasp and seal to handle <NUM>, and area <NUM> of elastomer seal <NUM> is preferably made slightly undersized so as to grasp and seal to control joystick <NUM>. This sealing may be further augmented by adding compression collars and/or suitable adhesives to areas <NUM>, <NUM>.

A stainless steel collar <NUM> provides additional support for the main tube <NUM> of shaft <NUM> where main tube <NUM> emerges from handle <NUM>. Note that main tube <NUM> of shaft <NUM> is bonded and sealed to handle <NUM>.

Handle <NUM> may be formed from two halves which are united during manufacturing, e.g., by bonding at <NUM>. <FIG> shows the proximal portion of endoscope <NUM> as it appears with the left side of handle <NUM> removed. The fiber optic illumination bundles <NUM> pass through the elongated hole <NUM> in outer tube <NUM> and then extend down to input connector <NUM>. The shielded electronic leads <NUM> from the image sensor assemblies <NUM> also pass through the elongated hole <NUM> in outer tube <NUM> and then extend down to suitable strain relief <NUM>. The flange <NUM> (<FIG> and <FIG>) of base <NUM> is retained and supported within matching receiving features <NUM> within each handle half.

Unwanted rotation of the steering mechanism is prevented by two opposing machined slots <NUM> formed in flange <NUM> and fitting over mating tabs (not shown) formed in receiving features <NUM>. The halves of handle <NUM> are sealed at all of the mating edge surfaces (e.g., at <NUM>).

Thus it will be seen that shaft <NUM> of endoscope <NUM> comprises a sealed camera module <NUM> (<FIG>) which has its distal working components (e.g., the image-forming optics and electronics shown in <FIG>, <FIG> and <FIG>) disposed within outer sleeve <NUM> so as to present its objective lens cells <NUM> and the distal ends of its fiber optic illumination bundles <NUM> to the region distal to outer sleeve <NUM>, with fiber optic illumination bundles <NUM> and electronic leads <NUM> extending proximally therefrom. Shaft <NUM> further comprises three decks <NUM>, <NUM> and <NUM> (<FIG> and <FIG>) which are connected together by an interior wire spine <NUM> and exterior metal bellows <NUM> so as to provide an articulating region to the shaft. Wire spine <NUM> further comprises a plurality of stacked spacer elements (e.g., rings) <NUM> coaxially mounted on the wire spine <NUM> so as to ensure consistent shaft length when the shaft is articulated. Distal deck <NUM> is received within and mated to outer sleeve <NUM> of sealed camera module <NUM>, and main tube <NUM> of shaft <NUM> extends proximally from proximal deck <NUM>. The proximal end of main tube <NUM> is secured to handle <NUM>. Actuating wires <NUM> are provided to articulate the distal end of shaft <NUM> and, to this end, the distal end of articulating wires <NUM> are secured to distal deck <NUM> and extend proximally along the shaft, terminating at swash plate <NUM> of the steering and brake assembly <NUM>. The disposition of swash plate <NUM>, and hence the disposition of the distal end of shaft <NUM>, is adjusted by manipulating knob <NUM> at the proximal end of steering and brake assembly <NUM>. The disposition of swash plate <NUM>, and hence the view position of the distal end of the shaft, is adjusted by moving control joystick <NUM>, and is locked in position by turning knob <NUM> of control joystick <NUM>, which applies a proximal force to brake pull wire <NUM>, which causes brake <NUM> to lock bearing ball <NUM> in position, whereby to lock swash plate <NUM> (and hence the distal end of the shaft) in position.

As shown, endoscope <NUM> is hand-operated. However, by linking at least two electromechanical, remotely-operated servos to at least two quadrants of the swash plate <NUM> and replacing handle <NUM> with a suitable adapter, steerable electronic stereoscopic endoscope <NUM> may be adapted for utilization with remotely-operated surgical robot systems.

It is well known in the art that endoscopes capable of withstanding multiple autoclave cycles must be sealed in such a way that all image-forming optics and electronics (e.g., the image sensor assemblies) are hermetically sealed by means of welding, high temperature soldering, brazing or other types of "hard" sealing methods, as opposed to elastomer seals or adhesives that are permeable to hot steam. Even very small amounts of moisture, if present in the optical path from the distal tip to the image sensor, will cause condensation and render the image unusable. The present invention lends itself to a complete hermetically-sealed autoclavable design. As seen in <FIG> and <FIG>, the steerable distal portion of the endoscope comprises metal bellows <NUM> soldered or welded to the metal decks <NUM>, <NUM> and <NUM>. Typically, prior art flexible or distally-steerable endoscopes include plastic steerable outer sheath portions that preclude attaining a fully autoclavable design.

Referring back to <FIG>, objective lens cells <NUM> may be designed in such a way that the distal optical lens or window is fabricated out of optical grade sapphire and soldered to the metal barrel of the lens cell. Note that this type of sapphire-to-metal sealing technology is well known in the art. The metal barrels of the camera lens cells <NUM> may then be welded to the module body <NUM> (<FIG>).

Alternatively the front lens of each objective lens assembly <NUM> may be soldered directly to the module body <NUM>. Similarly, thin sapphire windows may be soldered to the module body <NUM> at the distal ports of illumination fibers <NUM>, thereby providing for autoclavable hermetic seals at the distal surface of module body <NUM>. The outer sleeve <NUM> (<FIG>) may be welded or brazed to module body <NUM> at its distal end.

Referring to <FIG>, elastomer seal <NUM> may be replaced with a metal part welded or brazed to outer sleeve <NUM> and having hermetic feed-through connections for illumination fiber bundles <NUM> and image sensor cables <NUM>. Such hermetic feed-through connectors are known in the art. The modifications described above will encapsulate the most critical distal portion of the endoscope, which contains the optics and image sensors, into a fully hermetic assembly amenable to multiple autoclave cycles. The remaining portions of the endoscope are much less critical for small amounts of moisture and may be sealed by conventional sealing methods using elastomers and adhesives.

Thus, for example, <FIG> and <FIG> show an alternative configuration of the camera head featuring improved resistance to degradation from steam autoclave sterilization. More particularly, a distal stainless steel face (or deck) <NUM> features two holes <NUM> closely fitted with the conduit tubes <NUM> of illumination fibers <NUM>. Conduit tubes <NUM> are sealably soldered about their distal perimeter to each hole <NUM>. Also shown are two sapphire optical windows <NUM> with metalized edges which are also sealably soldered in holes <NUM> in stainless steel face <NUM>. These sapphire windows <NUM> are aligned with the optical axis of the two camera lens cells <NUM>. A second stainless steel face (or deck) <NUM> constrains the proximal ends of the conduit tubes <NUM> of illumination fiber optics <NUM>, i.e., conduit tubes <NUM> are sealably soldered in holes <NUM> in metal deck <NUM>. The camera heads <NUM>, and their corresponding lens cells <NUM>, are constrained and held in proper alignment within module body <NUM> (shown transparent in <FIG> and <FIG>). This assembled camera module is adhesively bonded within the inner diameter of the outer sleeve <NUM>. In addition to having the illumination fiber optic conduits sealably soldered, deck <NUM> also has two glass-to-metal sealed headers <NUM> (<FIG>) sealably soldered within holes <NUM> formed in deck <NUM>. The electronic leads <NUM> from the two image sensor assemblies <NUM> are conductively joined to the glass-sealed feed-through leads within the two glass-to-metal sealed headers <NUM>. The two illumination fiber bundles <NUM> are seen exiting their corresponding sealed conduits <NUM> in <FIG>. The two decks <NUM>, <NUM> are sealably soldered within the inner diameter <NUM> of outer sleeve <NUM>, resulting in an assembly sealed by solder about the perimeters of the fiber optic conduits <NUM>, sapphire windows <NUM> and glass headers <NUM>.

<FIG> and <FIG> show two connections, i.e., connection <NUM> for the illumination fibers <NUM> and connection <NUM> for electrical cable <NUM>. In an alternative embodiment, these two connectors may be combined into one universal cable carrying both illumination fibers and electrical wires, and may be permanently affixed to handle <NUM>. The proximal end of such a universal cable connects to a universal control unit (not shown) comprising a light source and the camera processor. Alternatively, such a universal cable may be detachably connected to handle <NUM>.

In another embodiment of the present invention, rather than connecting the illumination fiber bundles <NUM> to an external light source via connector <NUM> (<FIG>), the proximal portion of the endoscope (e.g. handle <NUM>) may contain an illumination engine based on white LEDs optically coupled to illumination fiber bundles <NUM> (<FIG>). As a result, an external light source will be no longer needed. The electrical power and control signals for the LEDs may be supplied via connector <NUM>. Alternatively, miniature white LEDs may be disposed at the distal end of the shaft of the endoscope, thereby eliminating illumination fiber bundles <NUM> altogether, or coupled to very short segments of illumination fiber.

In yet another embodiment of the present invention, the proximal portion of the endoscope contains a portable electrical power supply (e.g., a battery) and a wireless transceiver for providing a wireless video link to a corresponding transceiver in the external camera control unit. Thus, electrical cable connector <NUM> (<FIG>) may be eliminated. This embodiment, combined with the one described above in which LEDs are used for illumination, will render the endoscope completely untethered, thereby significantly improving user interface and freedom of movement for the operator of the device. The portable power supply (i.e., battery) will provide electrical power for image sensor assemblies, the LED light engine and the wireless video link circuitry.

Claim 1:
A steerable endoscope (<NUM>) comprising:
a shaft (<NUM>) having a distal end (<NUM>), a proximal end (<NUM>),
and an articulating region (<NUM>) therebetween,; and
a pair of electronic image sensor assemblies (<NUM>) optically aligned and fixedly bonded at the distal end (<NUM>) of the shaft (<NUM>) for acquiring an image of a remote site;
wherein the shaft (<NUM>) comprises a main tube (<NUM>), wherein the proximal end of the main tube (<NUM>) is secured to a handle (<NUM>) of the steerable endoscope (<NUM>),
characterised in that
the distal end (<NUM>) of the shaft (<NUM>) comprises a solid wire spine (<NUM>) having a distal end (<NUM>) and a proximal end (<NUM>), a first deck (<NUM>) mounted to the distal end of the wire spine (<NUM>) and a second deck (<NUM>) mounted to the proximal end of the wire spine (<NUM>), and a plurality of stacked spacer elements (<NUM>), each of which is coaxially mounted on the wire spine (<NUM>) between the first deck (<NUM>) and the second deck (<NUM>), wherein the steerable endoscope (<NUM>) further comprising a third deck (<NUM>) disposed intermediate the first deck (<NUM>) and the second deck (<NUM>), and further wherein the third deck (<NUM>) is slidably mounted on the wire spine (<NUM>), wherein the plurality of stacked spacer elements (<NUM>) are coaxially mounted on the wire spine (<NUM>) between the first deck (<NUM>) and the third deck (<NUM>), and between the third deck (<NUM>) and the second deck (<NUM>), wherein each of the first deck (<NUM>), the second deck (<NUM>) and the third deck (<NUM>) comprise a first hole (<NUM>), which allows electronic leads (<NUM>) to slide freely within the decks (<NUM>, <NUM>, <NUM>), and a second hole (<NUM>), which allows optical fibers (<NUM>) to slide freely within the decks (<NUM>, <NUM><NUM>), wherein the main tube (<NUM>) extends proximally from the third deck (<NUM>).