Patent Description:
Lasers have found a number of applications in medical procedures. Using suitably focussed and powerful laser beams, tissues can be excised, ablated or cut with fine control and with reduced bleeding. Example treatments are excision and vaporisation of benign and cancerous growths and fibromas, and aesthetic treatments. Conventionally, a CO<NUM> laser is used as the source of the beam producing light at a wavelength of <NUM>. Because this wavelength is not suitable for transmission through conventional optical fibres, where it would be absorbed by the silica, it is known to use either hollow flexible waveguides, or internally reflective articulated arms, to direct the beam to the site of operation.

<CIT> discloses a laser irradiating apparatus comprising a first laser source outputting a first laser beam, a second laser source outputting a second laser beam, said first beam being irradiated through a first light guide and said second laser beam being selectively irradiated through any one of said first light guide and a second light guide, signal generating means for generating a first signal for indicating use of the first light guide and a second signal indicating use of the second light guide, the first signal being generated when the first light guide is used and the second signal being generated when the second light guide is used, first assist gas supply means for supplying a first assist gas to the first light guide when the first signal is input, and second assist gas supply means for supplying a second assist gas to the second light guide when the second signal is input.

<CIT> discloses a laser device having an operating light source in the form of an infrared laser, a guide light source in the form of a visible laser, and a waveguide system for guiding light beams from the two lasers to an operating location, characterised in that the waveguide system comprises a mirror waveguide and a fibre waveguide which are selectively employed.

<CIT> discloses a connection unit for directing a laser beam coming from a laser source into a desired optical fibre. The connection unit comprises a slideway with conductors, and this slideway is mounted in the frame of the connection unit on the conductors, so as to move, and is equipped with members for directing the laser beam. The slideway can be moved with respect to the laser beam so that the desired directing member comes into the path of the laser beam and directs the beam into the desired fibre.

<CIT> discloses a radiation system comprising a waveguide to direct radiation from a first radiation source, a covering to cover at least part of the waveguide, and one or more optical fibers embedded in the covering to direct radiation from a second radiation source.

<CIT> discloses a light-transmittable composite tube, comprising a plurality of optical fibers, each of which has a light exit end and a light entrance end, whereby light enters the light entrance end and emits from the light exit end, and a plastic material, which is set around and combined with side surfaces of the optical fibers in a composite form to fix relative positions of the optical fibers to form a tubular structure serving as a fiber/plastic composite light guide tube, which has a light emitting end opening and a light receiving end opening, the light exit ends being arranged to distribute in the light emitting end opening and facing outward of the light emitting end opening.

According to a first aspect of the claimed invention, there is provided a dual port switching adaptor as defined by the appended independent claim <NUM>. The claimed dual port switching adaptor comprises: an opto-mechanical chassis comprising a main body, a connection part for mounting to a base unit, an input beam port to receive a main laser beam from the base unit, a first output port for detachable connection to a flexible hollow waveguide that has a hollow core within a cladding layer comprising a silica substrate, a second output port for connection to an articulated arm, and a switching element moveable between a first position and a second position to direct an input beam to one of the first output port or the second output port. The claimed adaptor further comprises an auxiliary guide beam source, and a beam combiner to direct an auxiliary guide beam to the first output port. The claimed adaptor is further characterized in that the auxiliary guide beam source is adapted to be actuated if a flexible waveguide is selected by a user, and in that the auxiliary guide beam source is mounted on a support plate which is adjustably connected to an auxiliary guide beam support of the opto-mechanical chassis by adjustable bolts, the auxiliary guide beam being controllable to be directed into the silica substrate of the cladding layer of the hollow waveguide.

The switching element may comprise a mirror.

The mirror may be moveable in a linear direction between the first position and the second position.

The claimed adaptor may comprise a linear actuator operable to move the switching element between the first position and the second position.

The input beam port may define an input beam path extending generally vertically, one of the first and second output ports may extend substantially vertically in line with the input beam path, and the other of the first output port and second output port may extend at an angle relative to the input beam path.

In one of the first position and the second position, the switching element may extend into the input beam path, and in the other of the first position and the second position, the switching element may be spaced from the input beam path.

The claimed adaptor may comprise a pressurized gas connection to allow supply of pressurized gas to the first output port.

According to a second aspect of the claimed invention there is provided a medical laser unit comprising a base unit, the base unit comprising a main laser source and a base unit output port, and an adaptor according to the first aspect of the claimed invention, the adaptor being mounted on the base unit such that the input beam port is connected to the base unit output beam port to receive the main beam from the main laser source, the base unit further comprising a main guide beam source and alignment optics, wherein the main guide beam is aligned with the main beam.

The main laser source may comprise a CO<NUM> laser to provide the main beam.

The medical laser unit may comprise a control unit operable to control the main laser source.

The medical laser unit may have a user input device to receive user instructions and transmit instructions to the control unit.

The control unit may be operable to control the switching element.

The medical laser unit may be operable to detect if a flexible waveguide is connected to the first output port.

If a flexible waveguide is detected, the control unit may be operable to control the switching element to direct the CO<NUM> laser beam to the first output port, and control the auxiliary guide beam source.

The medical laser unit may comprise a pressurised gas source and a pressurised gas controller, the control unit being operable to control the pressurised gas controller to direct cooling fluid to one of the first output port and an articulated arm.

An embodiment of the invention is described by way of example only with reference to the accompanying drawings wherein;.

With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

Referring now to <FIG>, a medical laser unit generally embodying the invention is shown at <NUM>. The medical laser unit comprises a base unit <NUM> and an adaptor <NUM>, which will be described hereafter in more detail. The base unit <NUM> comprises a main laser source (not shown), in the present example comprising a CO<NUM> laser, to generate a main laser beam with an output wavelength of <NUM>. As the main laser beam is in the infrared and so is not visible, a main guide laser (not shown) is also mounted in the base unit <NUM> to produce a visual main guide beam. Suitable beam combination and collimation optics are provided such that the base unit <NUM> outputs a main beam comprising the <NUM> beam and the main guide beam such that both beams are collimated and co-propagating. The base unit <NUM> further comprises a control unit shown in dashed outline at <NUM> and a control screen 13a which is operable to display operating information received from a control unit and to receive operator input to the control unit to control the laser output of the medical laser unit <NUM>. The main beam and main guide beam are transmitted to the adaptor <NUM>. The adaptor <NUM> has a first output port <NUM>, for connection to a hollow waveguide, and a second output port <NUM> for connection to an internally reflective articulated arm <NUM>. The adaptor <NUM> has a switching element, described below, which is controllable by the control unit <NUM> to direct the received main beam to one of the first output port <NUM> and second output port <NUM> as directed by an operator. Although not shown, it will be apparent that electrical connections are provided between the control unit <NUM> and the functional elements of the adaptor <NUM> so that the operation of the adaptor <NUM> can be monitored and controlled as appropriate. Where the adaptor <NUM> has a separate auxiliary control unit, this may be connected to the control unit <NUM> such that they operate as a single controller, preferably in a manner transparent to the operator.

The adaptor <NUM> will now be described in more detail with reference to <FIG>. The adaptor <NUM> comprises an opto-mechanical chassis generally shown at <NUM>. This is a solid, rigid body which serves as a reference surface with fixed location stops onto which other components can be mounted.

As seen in <FIG>, the opto-mechanical chassis comprises a main body <NUM> with a number of ports and recesses defined therein. The main body <NUM> is milled from aluminium to provide suitable rigidity, coefficient of thermal expansion and robustness. Preferably, the surfaces are also finished, for example by anodising, to produce a protective surface which has a matt texture to diffuse potentially hazardous laser reflections.

Within the main body <NUM>, input beam path <NUM> extends vertically from a lower part of the body <NUM>. First output beam path <NUM> and second output beam path <NUM> lead to the first output port 14and second output port <NUM> respectively. First output beam path <NUM> is coplanar with the input beam path <NUM> and second output beam path <NUM>, and is inclined at an oblique angle relative to the input beam path <NUM>. The second output beam path <NUM> is co-linear with input beam path <NUM>. The rigid body <NUM> has an output support part best shown at <NUM>, which has a third output beam path <NUM> extending therethrough which is co-linear with the first output beam path <NUM>. The support part <NUM> has an inclined connection face <NUM> which is perpendicular to the third output beam path <NUM> and provided with mounting points <NUM>.

Channel <NUM> extends in a linear manner into the main body <NUM> and has an angled inner face <NUM>. Input beam path <NUM> and first beam path <NUM> have respective openings 22a, 23a in the angled surface <NUM>, and the input, first and second beam paths <NUM>, <NUM>, <NUM> converge at point A within channel <NUM>.

To provide for an auxiliary guide beam as discussed in more detail below, the opto-mechanical chassis <NUM> comprises an auxiliary guide laser support <NUM> extending alongside the support part <NUM>. The support part <NUM> has an inclined rear surface <NUM> to support an auxiliary guide beam combiner as discussed in more detail below and a transversely extending auxiliary guide beam path 32a extending towards a corresponding board in the auxiliary guide beam support arm <NUM>.

At an upper surface <NUM> thereof, the main body <NUM> is provided with connection points <NUM> for connection to a beam combiner comprising the second output port <NUM> to direct the beam to an articulated arm <NUM>.

The opto-mechanical chassis <NUM> further comprises a vertical support <NUM>, on which the main body <NUM> is supported. In this example the vertical support <NUM> comprises a generally cylindrical body <NUM> defining an input beam port. An upper flange <NUM> engages a lower surface <NUM> of the body <NUM> and comprises a plurality of apertures <NUM> through which bolts <NUM> may pass to be received in threaded apertures (not shown) in the body <NUM>. At the lower end the vertical support <NUM> comprises an outwardly extending flange <NUM> with apertures <NUM> therein to enable the vertical support <NUM> to be connected to an optical bench surface <NUM> provided at the upper surface of the base unit <NUM>.

To switch the main beam, a switching apparatus or mirror assembly is shown generally indicated at <NUM>. The control switch comprises a mirror mount <NUM> best shown in <FIG> which has a vertical support plate <NUM>. The vertical support plate <NUM> comprises a mirror support arm <NUM> which is dimensioned to be received in channel <NUM>. At the end of support arm <NUM> there is provided a mirror support plate <NUM> which is inclined relative to the vertical support plate <NUM>. The mirror support plate <NUM> has a circular aperture <NUM> in which is received a plane mirror <NUM>, the reflective surface of the mirror being directed downwardly and to the left as shown in <FIG>. Although the present embodiment uses a plane mirror, it will be apparent that a curved mirror may be used if desirable, for example for focussing or beam conditioning purposes.

To support the mirror <NUM>, aperture <NUM> has an inwardly directed lip <NUM>. Three recesses <NUM> are located within the lip <NUM> which receive bearing balls <NUM>, the bearing balls <NUM> defining a correctly aligned surface. The mirror <NUM> when in position is supported by these bearing balls <NUM>. A retaining ring <NUM> is held in place by screws <NUM> against the back of the mirror <NUM>.

To provide for sliding movement of the mirror assembly <NUM>, the opto-mechanical chassis <NUM> is provided with horizontally extending guide rails <NUM>, <NUM> disposed above and below the channel <NUM>. <FIG> shows lower guide rail <NUM> in position and upper guide rail <NUM> in the correct orientation for connection to the chassis <NUM>. Upper guide block 70a is slidably mounted on the upper guide rail <NUM>, and lower guide blocks 71a, 71b are slidably mounted on the lower guide rail <NUM>. Vertical support plate <NUM> is connected to the guide blocks 70a, 71a, 71b such that the mirror assembly <NUM> is moveable lengthways of the channel <NUM>.

To provide for controlled sliding movement of the mirror assembly <NUM>, in the present example a linear actuator is provided comprising a stepper motor <NUM> connected to a threaded rod <NUM> extending through a suitable threaded nut <NUM>. Driving the stepper motor <NUM> causes the rod <NUM> to rotate and hence causes linear movement of the nut <NUM> and mirror assembly <NUM>. To avoid motor cleaving or motor sticking, the connection between the mirror assembly <NUM> and nut <NUM> preferably comprises a spring or flexible element to provide a degree of freedom between the mount and actuator. In the present example, each step of the stepper motor moves the mirror assembly by <NUM>. Screw <NUM> has a distal ball end located to provide an end stop for the mirror assembly <NUM>.

The mirror assembly <NUM> is thus movable by the linear actuator between first and second positions. In the first position, the mirror <NUM> extends between the input beam path <NUM> and second input beam path <NUM>, such that the main beam is reflected into first beam path <NUM>. Ideally, the mirror surface passes through point A in <FIG>. In the second position, the mirror assembly is offset from the beam paths <NUM>, <NUM>, <NUM> such that the main passes from the input beam path <NUM> to the second output beam path <NUM>.

To provide for detection of the position of the mirror assembly <NUM>, optical sensors <NUM>, <NUM> are provided to confirm when the mirror assembly <NUM> is in the first position or second position.

The first output port <NUM> for connection to a flexible waveguide and the auxiliary aiming beam will now be discussed with reference to <FIG>. <FIG> is a perspective view of the opto-mechanical chassis <NUM> showing the output port <NUM> and the auxiliary guide beam support <NUM>. As seen in <FIG>, the first output port <NUM> comprises a cylindrical element <NUM> with a flange <NUM> at one end which is connected to the angled surface <NUM> of the opto-mechanical chassis <NUM> by bolts 81a received in threaded bores <NUM>. A waveguide connection port <NUM> is mounted at the opposite end, protected by a lid <NUM>. The auxiliary guide beam source is shown at <NUM> comprising a red laser diode with its associated electronics mounted in a single element. The auxiliary guide beam <NUM> is mounted on a support plate <NUM> which is adjustably connected to the support <NUM> by adjustable bolts <NUM>. As shown in <FIG>, the auxiliary guide beam source <NUM> is directed at a beam combiner comprising an angled mirror <NUM> supported at the inclined rear surface <NUM> such that it is set at approximately <NUM>° to the cylindrical part <NUM> and the auxiliary guide beam source <NUM>. The angled mirror <NUM> is positioned such that the aiming beam is directed into the first output port <NUM> and the main laser beam, when directed through first output beam path <NUM>, passes through the mirror <NUM> substantially undeflected and into third output beam path <NUM>. It will be apparent that the beam acts to combine the main laser beam and auxiliary guide beam when the first output port <NUM> is in use.

An end part of a flexible waveguide as used herein is shown in <NUM> in <FIG>. The flexible waveguide <NUM> has a hollow core <NUM> within a silica substrate <NUM>. The inner surfaces of the silicate substrate <NUM> are coated with a reflective surface <NUM>, in the present example an interface film of silver deposited on the inner surface of the silicate substrate, and then a silver iodide coat deposited on the silver interface film. The silica substrate <NUM> is surrounded by a protective polymer coating <NUM>.

As the auxiliary guide beam will not be reliably propagated down the hollow core <NUM>, in the present example a guide beam is provided by directing the auxiliary guide beam into the silica substrate <NUM>. The bolts <NUM> are adjusted such that the aiming beam is offset from the main beam as illustrated in <FIG>. Referring to <FIG> the end of the flexible waveguide is held in a connector <NUM>, and the beams are aligned such that the main beam <NUM> is directed into the hollow core <NUM> and the auxiliary guide beam <NUM> is offset from the main beam <NUM> and enters the silica substrate <NUM>. The alignment can be carried using an apparatus such as that shown in <FIG>, where a dummy fibre holder <NUM> is used having the same dimensions as the waveguide holder <NUM>. A conventional optical fibre <NUM> is held within the dummy fibre holder <NUM> such that the end 99a of the fibre <NUM> is at the same offset position as the silica cladding <NUM> of the flexible waveguide <NUM>. A photodetector <NUM> is used to measure the light coupled into the alignment fibre <NUM>. Accordingly, the bolts <NUM> can be adjusted to vary the direction of the auxiliary guide beam <NUM> to maximise the signal at the photodetector unit <NUM> to confirm that the auxiliary guide beam is correctly aligned.

To provide cooling, a cooling fluid system is provided, in the present example a pneumatic cooling air system. A suitable cooling system is shown diagrammatically in <FIG>. The base unit is diagrammatically illustrated at <NUM> and a pneumatic control apparatus is shown at <NUM>. A distributor is shown at <NUM> which can receive pressurized from an internal compressor <NUM> provided within the base unit <NUM>, or from an external source <NUM>, which may be an external tank or an external pneumatic supply system. The distributor <NUM> is under the control of the control unit in the base unit <NUM>. A first pneumatic connection <NUM> leads from the distributor <NUM> to an air chamber <NUM> located in flow communication with the waveguide connection part <NUM>. A second pneumatic connection <NUM> is connectable to external flexible air tubes shown diagrammatically at <NUM> which extend along an outside surface of the articulated arm <NUM> and direct air towards an accessory or control element at the distal end of the articulated arm <NUM>, for example to be connected to an air inlet of the accessory. The supply of cooling fluid amongst other advantages helps to cool the flexible waveguide, when working at high energies, and also blows smoke or debris away from the operating point of the laser. Where a higher airflow is required, particularly for using a flexible waveguide at high energies, the internal compressor <NUM> may not be sufficient and the connection to an external source <NUM> is desirable. Although in the present example suitably filtered and dry compressed air is used, it will be apparent that any other suitable gas or gas mixture may be used.

The present invention is particularly advantageous in that it permits an existing medical laser unit <NUM> to be retrofitted with an adaptor <NUM> to provide more flexible operation. Accordingly, a medical laser unit <NUM> may be adapted by removing pre-existing articulated arm or flexible waveguide connection, and attaching an adaptor <NUM> to an optical bench part of the base unit <NUM> as described herein. The method of adapting the medical laser unit may also include connecting the optical waveguide connector part <NUM> to the control unit, and connecting the auxiliary guide beam laser <NUM> to the control unit. The actuator is similarly connected to the control unit. In the present example, the adaptor <NUM> is provided with a dedicated controller <NUM> mounted on the optical chassis <NUM>, and the auxiliary controller <NUM> is operable to transmit and receive information to the controller, and control the linear actuator and auxiliary guide beam laser in response to instructions from the controller. Similarly, the pneumatic distributor <NUM> may be controlled by the auxiliary controller <NUM> or entirely controlled by the main controller. In operation, the controller may detect the presence of an optical waveguide, or be informed of the presence of the optical waveguide by the auxiliary controller <NUM> and present options to the operator on the screen. If the operator selects the flexible waveguide, then the auxiliary guide beam laser is actuated, and the actuator is operated to move the switching apparatus to the first position. In the first position, the main laser beam is directed to the first output port <NUM> and into the flexible waveguide, and the auxiliary guide beam is directed into the silica cladding of the flexible waveguide as discussed herein. The pneumatic distributor <NUM> is operated to supply air under pressure through the flexible waveguide as discussed above.

Similarly, if the operator selects the articulated arm, the linear actuator is operated to move the mirror assembly to the second position. In this position, the main laser beam and the guide beam are unobstructed and pass through the input beam path, second beam path and are reflected within the articulated arm. Similarly, the pneumatic distributor is operated to supply pressurized air to the articulated arm connection. The auxiliary guide beam laser is not activated as the auxiliary guide beam is not required.

In the alternative, it will be apparent that a medical laser unit may be provided as a new unit with an adaptor <NUM> already installed. If so, it will be apparent that auxiliary controller <NUM> may be omitted and the linear actuator, auxiliary guide beam laser and flexible waveguide detector may be directly connectable to and operated by the main control unit. When a medical laser unit is modified to have an adaptor <NUM>, the software in the main control unit may be updated accordingly.

In the above description, an embodiment is an example or implementation of the invention. The various appearances of "one embodiment", "an embodiment" or "some embodiments" do not necessarily all refer to the same embodiments.

Although various features of the invention may be described in the context of a single embodiment, the features may also be provided separately or in any suitable combination. Conversely, although the invention may be described herein in the context of separate embodiments for clarity, the invention may also be implemented in a single embodiment.

Furthermore, it is to be understood that the invention can be carried out or practiced in various ways and that the invention can be implemented in embodiments other than the ones outlined in the description above.

Claim 1:
A dual port switching adaptor (<NUM>), comprising:
an opto-mechanical chassis (<NUM>) comprising a main body (<NUM>),
a connection part for mounting to a base unit (<NUM>),
an input beam port to receive a main laser beam from the base unit (<NUM>),
a first output port (<NUM>) for detachable connection to a flexible hollow waveguide (<NUM>) that has a hollow core (<NUM>) within a cladding layer comprising a silica substrate (<NUM>),
a second output port (<NUM>) for connection to an articulated arm (<NUM>), and
a switching element (<NUM>) moveable between a first position and a second position to direct an input beam to one of the first output port (<NUM>) or the second output port (<NUM>),
the adaptor (<NUM>) further comprising an auxiliary guide beam source (<NUM>), and a beam combiner to direct an auxiliary guide beam to the first output port (<NUM>),
the adaptor (<NUM>) being characterized in that
the auxiliary guide beam source (<NUM>) is adapted to be actuated if the flexible waveguide is selected by a user, and in that
the auxiliary guide beam source (<NUM>) is mounted on a support plate (<NUM>) which is adjustably connected to an auxiliary guide beam support (<NUM>) of the opto-mechanical chassis (<NUM>) by adjustable bolts (<NUM>) so that the auxiliary guide beam (<NUM>) is controllable to be directed into the silica substrate (<NUM>) of the cladding layer of the hollow waveguide (<NUM>).