Orthodontic laser tool head

Abstract

The present invention relates to a laser tool head comprising an optical array which comprises, in sequence, a focusing lens, an axial mirror, and an intersector mirror, wherein the focusing lens and axial mirror are sequentially positioned substantially along a pivot axis, the intersector mirror is positioned at a distance away from the pivot axis and is angled to reflect laser received from the axial mirror to intersect with the pivot axis at an intersection point that is a selected distance therealong. The focusing lens and the axial mirror rotate about the pivot axis without substantial lateral movement relative thereto, while the intersector mirror travels in a concentric arc relative thereto.

Description

ORTHODONTI C LASER TOOL HEADPRI ORI TY CLAI M

[0001] The present application claims priority from Australian provisional Application No. 2024901637, filed on 31 May 2024. The contents of the priority application are hereby incorporated herein by reference.TECHNI CAL Fl ELD

[0002] The present invention relates generally to the field of laser cutting and other laser tools.BACKGROUN D

[0003] Accurate machining methods are needed to cut out complex shapes from bulk material. One such complex shape is found in orthodontic inserts - the complexity arises from the U shape of the user’s teeth arrangement, as well as the unique, three-dimensional nature of each tooth within said arrangement. Orthodontic inserts such as tooth aligners are formed from a flat sheet of material through a method such as thermal moulding and then are cut out.

[0004] Alternate prior art mechanical methods, such as CNC cutting, are capable of three-dimensional cutting. However, these typically require substantial further processing in order to finish the product - in the case of an orthodontic insert, these further processes may involve removing burrs, polishing and smoothing the edges, and otherwise render the orthodontic insert safe and comfortable for the user.

[0005] Laser tools are tools that affect material by illum inating said material with a high-powered and focused laser. A well-known type of laser tool is a laser cutter, which is capable of perform ing the accurate, fine-detail machining needed to work bulk material into complex shapes. Additionally, the lack of physical machining of the material means burrs are significantly less likely to be present, and in general further processing of a complex shape after being cut out of bulk material by alaser tool is minim ised. As such, laser cutting offers a superior alternative, albeit one that carries its own disadvantages.

[0006] However, many prior art laser cutters can only cut the two-dimensional outline of the tooth aligner, and cannot account for the varying vertical shape along the edges thereof. Therefore, such a method requires additional processing to account for the vertical aspect of the user’s mouth shape.

[0007] Other prior art laser tools can have the vertical angle of the emitted laser adjusted, enabling a measure of vertical laser cutting as well as alteration of cutting direction (being the lateral angle of the em itted laser), but these carry their own host of problems. I n particular, it is desirable to move the touchpoint of the laser upon the material at a target cutting speed to ensure adequate cutting of the material without contacting a specific portion of the material for long enough that burn marks are formed. However, altering the cutting direction of a laser cutter - necessary to cut out an article with a complex shape due to the shifting topography of the article relative to the surrounding material - represents one of the more complex parts of laser cutter path calculation in that rotating or reangling the laser em itter will result in the laser touchpoint moving, thus requiring that the laser em itter itself be manoeuvred in an opposing direction to maintain a desired cutting speed. I n this sense, ‘cutting direction’ calculations and ‘cutting speed’ calculations are coupled together in a complex manner.

[0008] Referring to prior art Figure 1 , depicted on the left is diagram of a typical prior art three- axis laser tool P-02. The prior art laser tool P-02 comprises a gantry P-04 that enables movement along the X and Y axes, as well as a laser em itter P- 06 that is mounted to a mount P-08. The laser emitter P-06 em its a laser in cutting direction CD. Although not visible in the plan view, the laser em itter P-06 may also be vertically angled, such that the cutting direction CD extends in a line outwards and downwards. The mount P-08 may also be able to translate up and down to provide vertical, Z-axis movement (not depicted for clarity) . Some prior art laser cutting tools - such as the one depicted in prior art Figure 1 - may also have a mount P-08 that is able to rotate about a vertically-oriented axis, such that the cutting direction CD can be changed through arc R. I n other prior art lasercutting tools, the base is instead able to rotate so that the object being cut is turned.

[0009] Also depicted on the right-hand side of prior art Figure 1 is an example article P- 10 that is to be cut out of surrounding material (not shown). I n general, an article P- 10 is cut from surrounding material by the touchpoint of the emitted laser (i.e. the location where the em itted laser contacts the material) tracing along the outer perimeter of the article P- 10, with the shape of the edge of the cut at a point therealong being dependent upon the cutting direction of the laser at the time. An example cutting path is marked from initial reference point R1 sequentially through to a fourth reference point R4. As the skilled person will appreciate, the optimum cutting direction at a given point is perpendicular to the local surface to ensure that the edge is consistently formed and that the material is properly cut all the way through. An example cutting path is depicted from an initial reference point R1 sequentially through to a fourth reference point R4. Given this, the five marked cutting directions C1 - C5 correspond to the four reference points as follows: a. From the initial reference point R1 to the second reference point R2, the laser em itter P-06 must smoothly transition from C1 (the initial cutting direction) through to second cutting direction C2; b. The laser em itter P-06 m ust then im mediately pivot from the second to the third cutting direction (C2 to C3) , while the touchpoint remains constant; and c. The laser tool then moves to cut along the path from the second reference point R2, through the third reference point R3 and onto the fourth reference point R4, while smoothly transitioning from the third cutting direction C3, through the fourth cutting direction C4 and onto the fifth cutting direction C5.The skilled person will appreciate that the above sequence is heavily abbreviated and simplified, and the reference points R1 - R4 are arbitrarily selected points along the cutting path for the purpose of indicating particular complexities in the cutting process.

[0010] I n order to cut the shape out, the laser tool P-02 must manipulate the laser emitter P-06 in order to move the laser touchpoint along the cutting path. Referring now to prior art Figure 2, depicted are the movements along the X & Yaxes and rotation about axis R (all in dashed lines) of the prior art laser emitter P-06 in order to cut at each reference point R1 - R4 with corresponding cutting directions C1 -C5. The length of the cutting laser (depicted as a dot-and-dash line) is constant across each of the five images in the sequence depicted in prior art Figure 2. For clarity, the gantry P-04 is cut away when the laser emitter P-06 or article P- 10 would otherwise be obscured thereby. As depicted, an article requiring cutting from multiple angles may necessitate that the laser emitter P-06 move substantially, even if the actual touchpoint is not itself moving - for example, the transition between the second and third cutting directions C2,C3 occurs while the touchpoint remains at second reference point P- 14.

[0011] Even a relatively simple article can require m ultiple movements of the laser tool P-02 in order to fully cut the article out of the surrounding material, which require complex calculations in order to map out. I n addition, it is desirable for the laser touchpoint to move at a consistent speed along the cutting path, to ensure that the material is sufficiently illum inated by the laser to be cut all the way through, but does not get burned or otherwise damaged in a particular spot by the laser touchpoint lingering for too long. This adds to the complexity of the calculations, as certain movements of the laser emitter P-06 may need to be much faster than others - for example, the transition between the second and third cutting directions C2,C3 in prior art Figure 2 needs to happen as fast as possible to ensure that reference point P- 14 is not overexposed to the laser. The end result is that the path traversed by the laser em itter P-06 is not a direct match for the path traversed by the laser touchpoint.

[0012] An additional downside is that the size of an article P- 10 that a laser tool P-02 of given size can cut out is substantially limited. I n the example depicted in prior art Figure 2, the article P- 10 is approximately one-third the length of the gantry P-04 of the laser tool P-02, and yet cutting merely from the initial reference point R1 to the fourth reference point R4 requires that the laser emitter P-06 traverse nearly the entire length of the gantry. While this is dependent upon the length of the laser beam (which is exaggerated in prior art Figure 2 for clarity purposes) , the distance traversed by the laser em itter P-06, and the area through which the laser emitter P-06 sweeps as it manipulates the laser touchpoint will always be substantially larger than the actual perimeter and area of the article P-10, respectively. This lim its the size of an article P- 10 that can be cut out by a laser tool P-02 of a given size. Additionally, the number of articles that can be placed on a single sheet of material are limited as they m ust be spaced sufficiently for the laser emitter P-06 to sweep therebetween while rotating, etc., and the outermost articles must be close enough to the centre of the gantry P-04 that the laser em itter P-06 has sufficient range of motion to drive the laser touchpoint around them - thereby limiting both the possible article density and the overall number of articles that can be cut from a single sheet of material without repositioning.

[0013] The present invention aims to overcome, ameliorate or otherwise reduce the inefficiencies and other problems of the prior art through one or more of the embodiments disclosed below.DI SCLOSURE OF THE I NVENTI ON

[0014] I n a first aspect, the present invention lies in a laser tool head comprising an optical array that is adapted to be able to pivot about a pivot axis, the optical array comprising in sequence: a focusing lens having a focal point; an axial mirror; and an intersector mirror, wherein the focusing lens and axial m irror are sequentially positioned substantially along the pivot axis, the axial mirror being angled to reflect laser received from the focusing lens towards the intersector mirror, the intersector mirror is positioned at a distance away from the pivot axis and angled to reflect laser received from the axial m irror to intersect with the pivot axis at an intersection point that is a selected distance therealong, the focusing lens is adapted such that the focal point is at or substantially proximal to the intersection point, and when the optical array pivots about the pivot axis, the focusing lens, the axial mirror and the focal point rotate thereabout without substantial lateral movement relative thereto, the intersector mirror travels in a concentric arc relative thereto, and the selected distance does not substantially change.

[0015] I n an embodiment, the laser tool head further comprises a drive means adapted to drive the optical array to pivot about the pivot axis. I n a further embodiment, the drive means is a hollow shaft motor.

[0016] I n an embodiment, the focal point is offset from the intersection point by an offset amount.

[0017] I n an embodiment, the focusing lens is mounted within an adjustable lens mount adapted to be able to adjust a position of the focusing lens along the pivot axis, and the offset amount between the focal point and intersection point is adjusted by adjusting the position of the focusing lens.

[0018] I n an embodiment, the laser is substantially aligned with the pivot axis from at least immediately prior to the focusing lens through to the axial m irror. I n a further embodiment, the laser intersects the pivot axis at an angle between approximately 15 and approximately 90 degrees. I n a further embodiment, the angle is approximately 45 degrees.

[0019] Further or alternative embodiments of the invention may be disclosed herein or may otherwise become apparent to the person skilled in the art through the disclosure herein. These and other embodiments are considered to fall within the scope and object of the invention.DESCRI PTI ON OF Fl GURES

[0020] Embodiments of the present invention will now be described in relation to figures, wherein:Figures 1 & 2 depict a prior art laser tool and the movements thereof in cutting out an article;Figure 3 depicts an embodiment of a laser tool head of the present invention;Figure 4 depicts laser paths through an embodiment of the laser tool head pivoting; andFiguresd 5 & 6 depict a laser tool utilising an embodiment of the present invention and the movements thereof in cutting out an article.DETAI LED DESCRI PTI ON OF PREFERRED EMBODI MENTS

[0021] I n a first aspect, the present invention lies in a laser tool head to direct a laser, comprising an optical array having a focusing lens and a plurality of mirrorsto direct the laser, and a means for pivoting the optical array about an axis. The laser is directed to intersect with the axis, and as the optical array pivots about the axis, the laser continues to intersect with the axis at the same point therealong but from a different directional angle relative thereto.

[0022] I n an embodiment and with reference to Figure 3, the present invention lies in a laser tool head 10 comprising an optical array 12 that is adapted to be able to pivot about a pivot axis 16. I n an embodiment, the laser tool head may further comprise a drive means 14 that is adapted to drive the optical array to pivot about the axis. I n an embodiment, the optical array 12 may comprise, in sequence, a convergent focusing lens 18 having a focal point f, an axial m irror 20, and an intersector m irror 22. I n an embodiment, the focusing lens 18 and axial mirror 20 are sequentially positioned substantially along the pivot axis 16, so that when the optical array 12 pivots thereabout, the focusing lens and axial mirror substantially rotate thereabout, but otherwise remain aligned therewith. The axial mirror 20 is angled so as to receive laser that passes through the focusing lens 18 and reflect it towards the intersector m irror 22. I n an embodiment, the intersector mirror 22 is positioned at a distance away from the pivot axis 16, and is angled to reflect the laser that is received from the axial m irror 20 to intersect with the pivot axis 16 at an intersection point 24 that is a selected distance d therealong. While Figure 3 depicts the selected distance d as being relative to where the pivot axis 16 intersects with the base of the optical array housing 26, the person skilled in the art will understand that this is simply an arbitrary choice for the purpose of illustrating the invention, and that the selected distance d could be measured relative to any suitable element of the laser tool head 10 or a laser tool that the laser tool head is mounted to (not depicted in Figure 3).

[0023] Figure 3 also depicts a path of the laser 28 as a pair of dot-and-dashed lines, with a centreline of the laser marked as a dotted line (said dotted line overlapping the dashed line of the pivot axis 16 until the laser is reflected by the axial m irror 20) . I n an embodiment and as depicted, the focusing lens 18 is adapted such that received laser converges towards the focal point f, and that the focal point f is proximal to the intersection point 24. I n an embodiment, the focal point may be offset from the intersection point by an offset amount o, and may be arranged either before or after the intersection point 24. Without limiting thescope of the invention through theory, it is understood that the greatest power is located at the focal point of the laser as that is where the laser is most intensely focused. As such, it is considered that offsetting the focal point may enable embodiments of the laser tool head 10 of the present invention to account for thickness of a material being illuminated by the laser tool using the laser tool head 10. The person skilled in the art will appreciate that the travel distance of laser from the focusing lens 18 to the intersection point 24 does not change as the optical array 12 pivots about the pivot axis 16, and so the focal point f of the focusing lens 18 will remain at, or substantially proximal to, the intersection point 24, and if an offset distance a is applied, the offset distance o will remain constant. In an embodiment, the offset distance o is substantially between 0 mm and 3 mm from the intersection point 24. In an embodiment, the offset distance o is greater than 0.5 m m . In an embodiment, the offset distance o is greater than 1.0 mm. In a further embodiment, the offset distance is less than 2.5 mm . I n a further embodiment, the offset distance is less than 2.0 mm .

[0024] In an embodiment, the offset distance o may be adjustable through movement of the position of the focusing lens 18 along the pivot axis 16. I n such an embodiment, the focusing lens 18 may be mounted within an adjustable lens mount 30 that enables axial movement of the focusing lens. By way of non-lim iting example, the position of the focusing lens 18 may be controlled automatically through, e.g., computer input, sensor input (e.g. detection of material thickness) , or - as depicted - via a manual control means 32 such as a dial. I n an embodiment, the focusing lens position may be adjustable such that the offset distance a is able to be adjusted to within a range that is substantially between 0 mm and 3 mm .

[0025] Turning to Figure 4, depicted are a pair of views looking along the pivot axis 16 towards the intersection point 24, from a point between the axial m irror 20 and the intersection point. Although the focusing lens 18 and axial mirror 20 are behind the viewer and thus are not depicted, for clarity purposes their overlaying position is depicted by the dotted circle 34. Additionally, the laser path is depicted as though there is no offset distance o between the focal point f and the intersection point 24, but the person skilled in the art will appreciate that this is omitted for the purpose of clarity only and is not to be interpreted as excludingthe depicted principles from being considered applicable to such embodiments wherein an offset distance a greater than 0 mm is implemented.

[0026] The focusing lens 18 is flat relative to the viewpoint and pointing directly towards the intersection point 24, while the axial mirror extends outwardly from a centre point that overlaps the intersection point 24 to at least the dotted circle 34. Also shown is laser reflected from the axial mirror 20 to the intersector m irror 22 and subsequently to the intersection point 24. With reference to Figure 3, as the optical array 12 pivots about the pivot axis 16, the intersector m irror 22 moves from position A to position B along an arc 36 of constant radius that is concentric with the pivot axis 16. The dashed-line circle 38 depicts the full circle, concentric with the pivot axis 16, that the arc 36 lies upon. As the focusing lens 18 and axial mirror 20 both remain aligned with the pivot axis 16, and the angles of the axial and intersector mirrors 20,22 relative to one another and the distance therebetween remain constant, the optical array will continue to direct laser to intersect with the pivot axis 16 at the intersection point 24, and the selected distance d thereof will remain constant.

[0027] Without lim iting the scope of the invention through theory, it is considered that positioning the touchpoint of the laser 28 with the material at or substantially proximal to the intersection point 24 between the laser and the pivot axis 16 may enable more efficient laser cutter path calculations by decoupling ‘cutting direction’ from ‘tool position’. I n particular, the complexity that arises in prior art systems from needing to reposition the entire laser tool in order to reangle the laser (see, e.g., prior art Figure 2 and the transition from second to third cutting directions C2,C3 at reference point R2) may be alleviated through the use of an embodiment of the present invention. It is considered that embodiments of the present invention may enable the cutting direction to be changed without requiring the laser tool mount 44 itself to be repositioned in order to compensate for how the touchpoint will move as the cutting direction changes, unlike the depicted sequence shown in prior art Figure 2. This is because - as depicted in Figure 4 - the cutting direction changes by the laser tool head 10 of the present invention pivoting the optical array 12 about pivot axis 16, and the position of the intersection point 24 (which is analogous to the laser touchpoint) is aligned with said pivot axis 16 and so does not change.

[0028] As a result, calculating a path of the laser cutter to achieve a desired or target movement speed of the touchpoint (to, e.g., provide sufficient illum ination to cut, melt, or engrave the material or otherwise achieve one’s goal while preventing, e.g., burning of the material through over-illumination) may be performed without the calculations needing to account for induced movement of the touchpoint due to changing the cutting direction of the laser. Similarly, cutting direction calculations do not need to factor in how the laser tool as a whole m ust be repositioned in order to maintain the position and / or constant movement speed of the laser touchpoint. This may be contrast to the prior art laser tool P-02 depicted in Figures 1 & 2, wherein movement and cutting direction calculations are necessarily coupled - changing the cutting direction by rotation of the prior art laser em itter P-06 would induce movement in the touchpoint along a circular arc, unless it is counteracted by also moving the entire mount P-08 along the gantry P-04 in a matching counter-arc at the correct speed, which only becomes more complex if the change in cutting direction is carried out while the touchpoint is already moving (e.g. the transition from reference point R2 to reference point R4) . It may also be contrast to three-axis laser cutters wherein the laser assembly is mounted to a robotic arm capable of moving in three dimensions. I n such prior art laser tools, changing the cutting direction comprises physically moving each component of the robotic arm to manipulate the laser cutter to a new location and ‘re-angling’ it to point towards the desired touchpoint

[0029] I n an example use and with reference to Figures 5 & 6, the laser tool head 10 of the present invention may be a head or adaptor for use with a typical laser tool 40, which may be substantially sim ilar to the prior art laser tool P-02 depicted in prior art Figure 1 . The laser tool 40 itself is capable of translation along typically two or three axes (X, Y and Z, respectively) . Turning to Figure 5, depicted is a laser tool 40 having a gantry 42 and laser tool mount 44 (which may also house the laser emitter and / or a vertical or Z-axis adjustment mechanism) , and utilising an embodiment of the laser tool head 10, with the pivot axis 16 being aligned with the centre of the laser tool mount 44. With reference back to prior art Figures 1 & 2, Figures 5 & 6 further depict an article 46 of substantially same shape as prior art article 46, being cut out of material (not shown) , with the same four reference points R1 -R4 and corresponding cutting directions C1 -C5. Thesequence of positions and cutting directions, as well as size and relative positioning of the gantry 42 and article 46, is identical to that depicted in prior art Figure 2. As before, the gantry 42 is cut away when it would otherwise obscure elements. Additionally, the laser tool mount 44 and laser tool head 10 are partially transparent so as to illustrate the relative position of the perimeter of the article 46.

[0030] I n an embodiment and as previously explained, the components of the laser tool head 10 are shaped, arranged and otherwise positioned such that the intersection point 24 corresponds to the touchpoint of the laser on the material being illuminated thereby. The intersection point 24 (analogous to the laser touchpoint) is marked in the first image of the sequence depicted in Figure 6 so as to illustrate that it is central and directly below the laser mount 44 and laser tool head 10 from the perspective of the viewer, however it is not included in the further images in the sequence. As depicted in Figure 6 and with return reference to Figure 4, as the intersection point 24 (or laser touchpoint) is located along pivot axis 16 which is itself aligned with the centre of the laser tool mount 44, the laser tool mount 44 itself simply moves along a path that overlaps the perimeter of the article 46 and traces the cutting path (i.e. the article 46 perimeter) with the pivot axis 16 (and, if applicable, moving up and down along the Z-axis to keep the intersection point 24 correctly located on the material surface). I n such an embodiment, cutting direction is decoupled from movement of the laser tool mount 44 along the gantry 42. As such, calculations for control of the laser tool can be split into ‘movement’ calculations of the laser tool mount 44 along the X & Y axes (and Z axis, if applicable) and ‘angular’ calculations comprising pivoting of the optical array 12 about the pivot axis 16. As the person skilled in the art will appreciate, this may enable the touchpoint to be moved along a cutting path (i.e. the perimeter of the article 46) at a constant speed merely by moving the laser tool mount 44 at the desired speed. This may be visually observed in the movement arrows (dashed line arrows) for each successive image in sequence, particularly when contrast against the same in prior art Figure 2.

[0031] I n an embodiment, the drive means 14 may comprise a hollow-shaft motor. The laser source may be on one side of the hollow-shaft motor 14 while the optical array 12 is on the other side thereof, such that the pivot axis 16 andthe laser both pass through the hollow shaft of the said hollow-shaft motor. This may enable the laser source to be more accurately aligned with the pivot axis 16, thereby elim inating a potential source of lateral drift error that may otherwise occur as the laser tool head 10 is pivoted. Furthermore, it is considered that allowing the laser 28 to pass through the drive means 14 may enable pivoting of the laser tool head 10 without requiring either the source to be rotatably mounted or the laser tool head 10 to further comprise additional optical elements to capture and direct a received laser around the drive means 14 and back into alignment with the pivot axis 16.

[0032] I n an embodiment and as depicted in Figure 3, the laser that is to be directed through the optical array 12 is substantially aligned with the pivot axis 16 from at least im mediately prior to the focusing lens 18, through to being received by the axial mirror 20. I n an embodiment, the laser that is directed through the optical array 12 intersects the axis at an angle between approximately 15 and approximately 90 degrees. As the laser 28 may be substantially conically shaped due to being focused onto the focal point by the focusing lens 18, the angle may be measured relative to a centreline of the path of the laser. I n a further embodiment, the angle is between approximately 30 and approximately 70 degrees. I n a further embodiment, the angle is approximately 45 degrees.

[0033] While the invention has been described with reference to preferred embodiments above, it will be appreciated by those skilled in the art that it is not limited to those embodiments, but may be embodied in many other forms, variations and modifications other than those specifically described. The invention includes all such variation and modifications. The invention also includes all of the steps, features, components and / or devices referred to or indicated in the specification, individually or collectively and any and all combinations or any two or more of the steps or features.

[0034] I n this specification, unless the context clearly indicates otherwise, the word “comprising” is not intended to have the exclusive meaning of the word such as “consisting only of”, but rather has the non-exclusive meaning, in the sense of “including at least”. The same applies, with corresponding grammatical changes, to other forms of the word such as “comprise”, etc.

[0035] Other definitions for selected terms used herein may be found within the detailed description of the invention and apply throughout. Unless otherwise defined, all other scientific and technical terms used herein have the same meaning as com monly understood to one of ordinary skill in the art to which the invention belongs.

[0036] Any promises made in the present document should be understood to relate to some embodiments of the invention, and are not intended to be prom ises made about the invention in all embodiments. Where there are prom ises that are deemed to apply to all embodiments of the invention, the applicant / patentee reserves the right to later delete them from the description and they do not rely on these prom ises for the acceptance or subsequent grant of a patent in any country.

Claims

CLAI MS1 . A laser tool head comprising: an optical array that is adapted to be able to pivot about a pivot axis, the optical array comprising in sequence: i. a focusing lens having a focal point; ii. an axial mirror; and iii. an intersector m irror; wherein the focusing lens and axial m irror are sequentially positioned substantially along the pivot axis, the axial m irror being angled to reflect laser received from the focusing lens towards the intersector mirror; the intersector m irror is positioned at a distance away from the pivot axis and angled to reflect laser received from the axial m irror to intersect with the pivot axis at an intersection point that is a selected distance therealong; the focusing lens is adapted such that the focal point is at or substantially proximal to the intersection point; and when the optical array pivots about the pivot axis, the focusing lens and the axial mirror and the rotate thereabout without substantial lateral movement relative thereto, and the intersector m irror travels in a concentric arc relative thereto, and the selected distance does not substantially change.

2. The laser tool head of claim 1 , further comprising a drive means adapted to drive the optical array to pivot about the pivot axis.

3. The laser tool head of claim 2, wherein the drive means is a hollow shaft motor.

4. The laser tool head of any one of the above claims, wherein the focal point is offset from the intersection point by an offset amount.

5. The laser tool head of claim 4, wherein the focusing lens is mounted within an adjustable lens mount adapted to be able to adjust a position of the focusing lens along the pivot axis;the offset amount between the focal point and intersection point being adjusted by adjusting the position of the focusing lens.

6. The laser tool head of any one of the above claims, wherein the laser is substantially aligned with the pivot axis from at least im mediately prior to the focusing lens through to the axial mirror.

7. The laser tool head of any one of the above claims, wherein the laser intersects the pivot axis at an angle between approximately 15 and approximately 90 degrees.

8. The laser tool head of claim 7, wherein the angle is approximately 45 degrees.

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