FI82370B - OPERATIONSHUVUD FOER EN LASERANORDNING. TRANSFERRED PAEIVAEMAEAERAE-FOERSKJUTET DATUM PL 14 ç 12.01.88. - Google Patents

Description

1 82370

OPERATING HEAD FOR LASER EQUIPMENT - OPERATIONSHUVUD FÖR EN LASERANORDNING

The invention relates to an operating head for a laser device 5, which laser device comprises a laser source and an optical conductor for conducting a laser beam from a laser source to an operating head made of an optically transparent solid and tapered to a tip. to direct the laser beam at the desired target in order to avoid stray radiation and its side effects, and to precisely aim the laser-15 beam at the desired target. Furthermore, such devices are intended to produce a reproducible radiation effect so that the operating head can be held in the object to be treated and the distance of the operating head from the object to be treated cannot fluctuate and adversely affect the treatment result.

An operating head as described above is known e.g. U.S. Patent No. 4,693,244. The operating head shown includes a uniform, rod-like and round base portion and an associated conical round tip. 25 In the publication, the operating head or, more precisely, the tapered tip of the operating head has a · conical cross-sectional shape and a substantially circular cross-section. However, such a round operating head is very cumbersome to use. It is not able to make exactly 30 cuts of any kind due to the round shape of the tip. The conical round tip has a high resistance in the surgical wound when it is moved. With the conical tip of the operating head, mainly only the laser beam can be aimed at the desired target. Other operations must be performed with a separate scalpel. The use of a separate scalpel is generally cumbersome and then essentially impossible when the simultaneous use of a laser beam with a scalpel is desirable or necessary.

The object of the present invention is to provide an operating head for a laser device which is suitable for use simultaneously for both cutting and for guiding laser light to a cutting object.

With respect to the features of the invention, reference is made to the characterizing part of claim 1.

The invention is based on the basic idea that the tip of the operating head has a substantially elliptical cross-section, the cutting edge of the tip in the cutting direction is circular and the cross-section of the cutting edge of the tip is circular. Preferably, the ratio of the thickness of the tip of the operating head to its width is less than 4: 5, e.g. 4: 5 to 1:10, preferably 2: 3 to 1:10 suitably 1: 2 to 1: 5.

By the tip of the operating head is meant in this context the part forming the extension of the base part of the operating head and the part forming its peak, the cross-section 20 of which decreases towards the apex, i.e. the extreme, sharpest and narrowest part of the operating head.

The radius of curvature of the flat and bladed edge of the tip of the operating head according to the invention can be very small, i. the blade can be very sharp, the radius of curvature of the blade edge 25 being of the order of e.g. n * 10 "· * mm, where n is greater than or equal to 1. In this case, the tip of the operating head can naturally be used to make very demanding cuts, i.e. mainly like a conventional cutting knife.

30 At the knife-like tip of the operating head, the propagation of the beam does not have the axial symmetry typical of a conical tip. Depending on the intensity of the flattening, the rays tend to be directed at the edges of the knife.

35 The cutting properties of the knife-like tip of the operating head are better than those of the conical one, since when the radiation is discharged from the edges of the knife, the cutting effect I: 3 82370 occurs over a wider range. At the conical tip, the shear effect is point-like; the knife-shaped tip cuts all over its edge. This feature allows deeper incisions to be made with a knife-like tip.

5 Because the knife-shaped tip of the operating head is flat, it moves considerably more easily than the round conical tip in the incision.

The flat shape of the tip of the operating head also improves the coagulation properties. The large area of the knife-like tip 10 coagulates a large area at a time.

When the laser head emits higher light powers of the laser beam to the cutting target and the tip of the operating head is Round, mainly elliptical, no large power-15 sea buckthorns are formed at the edge of the blade and the blade is not damaged.

Depending on the material, the operating head according to the invention is suitable for connection to any laser device known per se for use in medicine and medical treatment, such as Nd-YA-20 G laser device, Er-YAG laser device, Ar laser device, CO lar device, COa laser device, Excimer to a laser device, a dye laser device, etc. Further, the operating head can be connected to the laser source by means of any optical conductor known per se, such as a mirror arm, an optical fiber or the like. The connection of the operating head to the optical conductor takes place in such a way that the laser beam passing through the optical conductor is guided inside the operating head in a manner known per se.

The invention will now be described in detail with reference to exemplary embodiments with reference to the accompanying drawings, in which Figure 1 shows a side view and a diagrammatic view of an operating head according to the invention, Figure 2 shows a section II-II from Figure 1, Figure 3 shows a section according to Figures 1-2. enlarged side edge of the operating head, Fig. 4 shows the operating head according to Figs. 1-3, seen from the wide side direction, Fig. 5 shows a longitudinal section 5 of the tip of the operating head according to another embodiment of the invention, Fig. 6 shows a cross section according to a third embodiment of the invention from the tip of the operating head, Fig. 7 shows a cross-section of the tip of the operating head according to a fourth embodiment of the invention.

Figure 1 shows an operating head for a laser device according to the invention, which laser device comprises a laser source 2 known per se (shown schematically in Figure 1) and an optical conductor 3 arranged to guide a laser beam from a laser source to an operating head. The operating head is made of solid Allon lengths. , and it tapers to a tip 4. In Fig. 1, the operating head 1 is further provided with a handle 6, and a special connecting device 7 which connects the optical fiber 3 to the operating end 1 and guides the laser beam along the optical fiber to the operating end. The operating head 1 comprises a rod-like, e.g.

25 a uniform base 5 of uniform thickness and cross-section, to which the tip 4 joins tapering to the top 8.

The tip 4 of the operating head 1 is flat and bladed in shape. The flat and sharp shape of the tip is clearly shown in Figures 2-4, in which Figures 2 and 3 show the tip of the operating head cut along line II-II and enlarged (Figure 3). Further, Fig. 4 shows the operating tip as viewed from the direction of its flat or wide side, i. on top of the tip. According to the figures, the tip is flat and knife-shaped, the tip edge 9 forming a sharp cutting edge.

Figure 5 shows the tip of an operating head according to another embodiment of the invention, cut in the axial direction of the operating head and substantially perpendicular to the flat side of the flat blade.

In the following, the course of the beam in the tip 5 of the operating head according to Fig. 5 will be considered in detail.

Examining the passage of the laser beams in the eg thick, base part of the operating head 1, it is stated that the laser beams maintain the same angle α with respect to the axis of the operating head that they had immediately after penetrating the operating head. If the evenly thick part of the operating head is long and thin enough, the outermost rays of the beam formed by the laser beams may hit the surface of the base part of the operating head. The angle of incidence is then so large that total reflection occurs and the radius continues 15 distances at the same but opposite sign angle.

Considering the propagation of the outermost radius of the radiation beam (forming the steepest angle with the axis of the tip) at the knife-like tip when the angle between the surface of the tip 20 and the axis is a. The radius first hits the surface of the tip at A? in reflection, the input and reflection angles are equal. Immediately after reflection, the radius forms an angle α + 0t with the surface of the tip. The next time you hit the surface on the opposite side of the tips, the beam has an incidence angle of 90 * - (3a + 0¾.). Thus the beam continues to pass when the angle of incidence is saadι.η - 90 '- [(2m - l) a + et], 01. » > o (l) in a reflection of 30 orders of m. When the angle of incidence θι · »becomes negative, the radius begins to return.

As the angle of incidence decreases with increasing order of reflection, the total reflection 35 experienced by the beam ceases at some point and the beam passes through the surface. For each reflection where the angle of incidence is less than the cut-off angle of the total reflection, a portion of the beam power passes through the surface of the beam 6 82370 as the beam is divided into a reflected and transmitted portion.

If, in the reflection, the angle of incidence m is less than the cut-off angle, the transmitted radius with the axis forms the angle 1Q Tm = 90 ° - a - arcs (2) where n0 is the refractive index of the surrounding material (air or tissue) and n * is the refractive index of the operating material.

It is observed from Equation (2) that when the radius has a gentler angle in the evenly thick part of the operating head (the angle varies between - 8 «. - 8 * 0, i.e. the input angle θι.„, Increases, 20 tapers the radiation beam from the tip. The angle 8 * depends on the fiber Correspondingly, as the angle α of the tip decreases, the radiation beam (Tm increases).

Thus, in the embodiment of Figure 5, 25 i.e. at the knife-like tip the rays tend to be directed at the edges of the knife. This gives the flat and bladed tip of the operating head excellent cutting properties, since when the radiation is released from the edges of the knife, the cutting effect occurs over a wider area. In this case, the 30 knife-shaped tip cuts at its entire edge.

Figure 6 shows a cross-section of the tip of the operating head, where the ratio of the thickness T of the tip to its width B is of the order of about 1:10. In Figure 7, the corresponding ratio is of the order of about 2: 3. The tip of the operating head shown in Figures 6 and 7 and also 35 as in Figure 2 is substantially oval in cross section. The radius of curvature of the cutting edge at the junction of the base and the tip corresponds mainly to the radius of curvature of the base, in the region of the tip 8 and in its vicinity, e.g. about 1/10, 40 up to 1/2 of the length of the tip towards the base can be as short as nx 10 3 mm, where n is greater than or equal to 1.

The tip of the operating head can be formed of any material known per se in the art, such as alumina, e.g. sapphire, silicon oxide, e.g. quartz, etc., and other optically transparent and relatively high temperature resistant material.

The embodiments are intended only to illustrate the invention and the embodiments of the invention may vary within the scope of the appended claims.

Claims (4)

8 82370 An operating head (1) for a laser device for making incisions, the laser device 5 comprising a laser source (2) and an optical conductor (3) for guiding a laser beam from a laser source to an operating head made of an optically transparent solid and tapered into a flat tip (4). the tip 10 (4) of the operating head (1) has a substantially elliptical cross-section, the cutting edge of the tip in the cutting direction is circular and the cross-section of the cutting edge of the tip (4) is circular. Operating head according to Claim 1, characterized in that the ratio of the thickness (T) of the tip (4) of the operating head (1) to its width (B) T: B is 4: 5 to 1:10. Operating head according to Claim 1 or 2, characterized in that the sharpness of the tip (4) of the operating head 20 (1), i.e. the radius of curvature (r) of the edge of the blade is of the order of n · 10 “3 mm, where n is greater than or equal to 1. Operating head according to one of Claims 1 to 3, characterized in that the base part (5) of the operating head (1) is substantially circular. 9,82370