LASER BRUSH

Abstract

Applicator for ameliorating alopecia, for improving quality, color and density of hair, and/or for improving a condition of a scalp of a person by laser light, comprising means for splitting at least one laser beam into at least two partial laser beams and at least two output means, each adapted to apply at least one of the at least two partial laser beams to the person, wherein the at least two output means are adapted such that hair can be accommodated at least partly in between them.

Claims

1. Applicator for ameliorating alopecia, for improving quality, color and/or density of hair, and/or for improving a condition of a scalp of a person by laser light, comprising: means for splitting at least one laser beam into at least two partial laser beams; at least two output means, each adapted to apply at least one of the at least two partial laser beams to the person; wherein the at least two output means are adapted such that hair can be accommodated at least partly in between them.

2. Applicator according to claim 1, wherein the at least two output means are adapted to be placed on a tissue surface of the person.

3. Applicator according to claim 1, wherein at least one of the output means comprises at least one of: a spacer tube, a hollow waveguide and/or an optical fiber.

4. Applicator according to claim 1, wherein at least one of the output means comprises at least one of: an output lens and/or a window that is transparent with respect to the at least one laser beam.

5. Applicator according to claim 1, wherein at least one of the output means is flexible and/or elastic.

6. Applicator according to claim 1, wherein at least a portion of at least one of the output means is releasably attached to the applicator.

7. Applicator according to claim 1, wherein the applicator is adapted such that the at least two partial laser beams are applied to at least 50%, preferably at least 80%, more preferably at least 90%, most preferably 100% of a target area, when the applicator is moved over the target area along a preferred direction of movement.

8. Applicator according to claim 1, wherein the applicator is adapted such that the at least two partial laser beams are applied with an overlap of at most 50%, preferably at most 20%, more preferably at most 10%, even more preferably at most 1%, most preferably 0%, when the applicator is moved over a target area along a preferred direction of movement.

9. Applicator according to claim 7, further comprising an indication of the preferred direction of movement, wherein the indication is perceivable by a user at least while the at least two partial laser beams are applied to the person.

10. Applicator according to claim 7, wherein the at least two output means are arranged in at least one column comprising N output means, with an average distance l between the N output means, the N output means adapted to apply partial laser beams of average diameter D; and wherein the preferred direction of movement of the applicator is defined by an angle with respect to the at least one column in the range of 0.5α to 1.5α, preferably 0.8α to 1.2α, more preferably 0.9α to 1.1α, most preferably 0.95α to 1.05α, wherein $\sin \alpha =\frac{D}{l}.$

11. Applicator according to claim 1, wherein the at least two output means are arranged in a plurality of columns and rows essentially perpendicular to each other.

12. Applicator according to claim 11, wherein a first column comprises N output means, with an average distance l between the N output means, the N output means adapted to apply partial laser beams of average diameter D; and wherein the first column is spaced from an adjacent second column of output means by a distance in the range of 0.5 L to 1.5 L, preferably 0.8 L to 1.2 L, more preferably 0.9 L to 1.1 L, most preferably 0.95 L to 1.05 L, wherein $L=N\frac{D}{\sqrt{1-D^2/l^2}}.$

13. Applicator according to claim 1, wherein the at least two output means are arranged in a two-dimensional pattern of points and adapted to apply partial laser beams of average diameter D, wherein the two-dimensional pattern of points is obtainable, from a column of points with an average distance l between the points, by translating one or more of the points of the column along a direction having an angle α with respect to the column, wherein $\sin \alpha =\frac{D}{l}.$

14. Applicator according to claim 1, wherein the applicator further comprises at least one of: means for receiving the at least one laser beam, in particular from an articulated arm and/or fiber; beam expanding means; reflective means, in particular a plurality of mirror segments; a plurality of apertures, each aperture corresponding to at least one partial laser beam; and/or a plurality of lenses, each lens corresponding to at least one partial laser beam.

15. Applicator according to claim 1, wherein the applicator comprises a flat mirror and/or a plurality of hexagonal lenses.

16. Applicator according to claim 1, wherein the at least one laser beam is a high-energy laser beam.

17. Method for ameliorating alopecia, for improving quality, color and/or density of hair, and/or for improving a condition of a scalp of a person by laser light, comprising the use of an applicator according to claim 1.

18. Method for ameliorating alopecia, for improving quality, color and/or density of hair, and/or for improving a condition of a scalp of a person by laser light, comprising: directing at least one laser pulse comprising a wavelength onto a tissue surface of the person, wherein an energy delivery time t.sub.ed of the at least one laser pulse, during which a second half of the pulse energy is delivered, is chosen sufficiently short, so that, given the wavelength and thus a corresponding penetration depth δ of the at least one laser pulse, t.sub.ed+(1/A)(δ+√(2 A t.sub.ed)).sup.2<900 microseconds, wherein A=0.1 mm.sup.2 s.sup.−1.

19. Method according to claim 18, wherein the wavelength is in the range of 2.6 micrometers to 3.2 micrometers, and/or wherein a fluence F of the at least one laser pulse is chosen to be below the ablation threshold, preferably between 0.01 J/cm.sup.2 and 3 J/cm.sup.2, between 0.05 and 2 J/cm.sup.2, between 0.1 and 1.5 J/cm.sup.2.

20. Method according to claim 18, wherein the wavelength is in the range of 800 nanometers to 1200 nanometers, and/or wherein a fluence F of the at least one laser pulse is chosen to be below the ablation threshold, namely between 0.5 J/cm.sup.2 to 10 J/cm.sup.2 or between 20 J/cm.sup.2 and 1000 J/cm.sup.2.

21. Method according to claim 18, wherein the wavelength is in the range of 1.8 micrometers to 11 micrometers, preferably 0.8 micrometers to 2 micrometers or 9.1 micrometers to 10.2 micrometers.

22. Method according to claim 18, further comprising the use of an applicator including: means for splitting at least one laser beam into at least two partial laser beams; and at least two output means, each adapted to apply at least one of the at least two partial laser beams to the person; wherein the at least two output means are adapted such that hair can be accommodated at least partly in between them.

Description

4. BRIEF DESCRIPTION OF THE FIGURES

[0071] Possible examples of the present invention will be described in more detail in the subsequent detailed description with reference to the following figures:

[0072] FIG. 1: Schematic cross section of an example of an applicator according to the present invention;

[0073] FIG. 2: Sectional view of an example of an applicator according to the present invention;

[0074] FIG. 3: Sectional view of an example of an applicator according to the present invention;

[0075] FIG. 4: Schematic top/bottom view of output means and/or partial laser beams applied thereby of an example of an applicator according to the present invention;

[0076] FIG. 5: Schematic top/bottom view of partial laser beams applied by output means of an example of an applicator according to the present invention;

[0077] FIG. 6: Schematic cross section of an example of an applicator according to the present invention;

[0078] FIG. 7: Sectional view of an example of an applicator according to the present invention;

[0079] FIG. 8A: Schematic top/bottom view of a plurality of lenses of an example of an applicator according to the present invention;

[0080] FIG. 8B: Schematic top/bottom view of partial laser beams applied by output means of an example of an applicator according to the present invention.

5. DETAILED DESCRIPTION OF POSSIBLE EXAMPLES

[0081] For the sake of brevity only a few examples will be described in the following. The skilled person will recognize that the specific features described with reference to these examples may be modified and combined differently and that individual features may also be omitted if they are not essential. The general explanations in the sections above will also be valid for the following more detailed explanations.

[0082] FIG. 1 shows a schematic cross section of an example of an applicator 100 according to the present invention. Therein, a laser beam 110 is received (from the right in FIG. 1). Laser beam 110 may be collimated. In some examples, laser beam 110 may be received from an articulated arm and/or an optical fiber or similar optical means. In some examples, such an articulated arm or optical fiber may feed laser beam 110 to the applicator from an external laser source (not shown), i.e., from a laser source not arranged within or at the applicator. In particular, the external laser source may be a high-energy laser, with an ability of a power output of more than 0.5 W. Laser beam 110 may be received along a direction essentially parallel to a handle of applicator 100, e.g., horizontally within the drawing plane of FIG. 1.

[0083] Applicator 100 may comprise beam expanding means 130, and laser beam 110 may be expanded by means of it. In the example of FIG. 1, beam expanding means 130 comprise two beam-expanding lenses, one (bi)concave, one (bi)convex. However, in other examples, beam expanding means such as beam expanding means 130 may comprise any number of beam-expanding lenses of any shape. In other examples, beam expanding means such as beam expanding means 130 may comprise additional or alternative optical components other than beam-expanding lenses.

[0084] After having passed the beam expanding means, laser beam 110 impinges upon reflective means 140 of applicator 100. In the example of FIG. 1, reflective means 140 comprises a plurality of mirror segments 142 and 144 (in some examples, only a single segment 142 may be provided). Mirror segments 142 and 144 may each comprise a reflective surface having an elongated, rectangular shape. In FIG. 1, this elongated, rectangular shape may extend perpendicular to the drawing plane and/or perpendicular to the direction along which laser beam 110 is received. Mirror segments 142 are oriented substantially parallel to the direction along which laser beam 110 is received. In contrast, mirror segments 144 are angled with respect to laser beam 110. In the example of FIG. 1, mirror segments 144 are angled by substantially 45°, but it is also possible to arrange them at an angle in the range of 20° to 70°, 30° to 60° or 40° to 50°, for example, with respect to the direction along which laser beam 110 is received. Hence, mirror segments 144 (re)direct laser beam 110 by substantially 90°, i.e., mirror segments 144 (re)direct laser beam 110 such as to propagate in a direction that is substantially perpendicular to the direction from which laser beam 110 is initially received. Since mirror segments 142 are oriented substantially parallel to laser beam 110 as it is received, effectively only mirror segments 144 take part in (re)directing laser beam 110 in the example of FIG. 1.

[0085] In some examples that comprise mirror segments like mirror segments 142 which are oriented substantially parallel to laser beam 110 as it is received, these mirror segments may not be reflective. In yet other examples, there may be more than two kinds of mirror segments such as mirror segments 142 and 144, each kind arranged at a specific angle with respect to the direction along which laser beam 110 is received.

[0086] In the example of FIG. 1, reflective means 140 is sized to—by virtue of at least mirror segments 144—(re)direct laser beam 110 along its full diameter and/or cross section. In the example of FIG. 1 as well as all subsequent examples, it is assumed for convenience that laser beams such as laser beam 110 comprise a substantially circular cross section. However, the skilled person will realize that the means comprised in the applicator may readily be adapted for use with laser beams such as laser beam 110 of different cross sections, e.g., square, rectangular, hexagonal or elliptic cross sections. In other examples, reflective means such as reflective means 140 may be sized to fully (re)direct laser beams of a larger or smaller diameter and/or cross section than laser beam 110.

[0087] Due to the arrangement of mirror segments 142 and 144, laser beam 110 is split into a number of laser beam strips (not shown/labelled) that propagate in a direction that is substantially perpendicular to the direction from which laser beam no is initially received. In some examples, the number of resulting laser beam strips may be equal to the number of mirror segments such as mirror segments 144. In the example of FIG. 1, these laser beam strips comprise a substantially rectangular cross section, corresponding to the shape of mirror segments 144. The laser beam strips are spaced apart from each other along the direction from which laser beam 110 is initially received. In the example of FIG. 1, their relative distance corresponds to the size of mirror segments 142, more particularly to the cross-sectional dimension of mirror segments 142 that extends within the drawing plane.

[0088] The laser beam strips are (re)directed towards at least two output means 160. Output means 160 may comprise an elongated shape that may extend substantially perpendicular to the direction from which laser beam 110 is initially received. In the example of FIG. 1, output means 160 comprise a substantially cylindrical shape. In other examples, output means such as output means 160 may comprise a different shape, such as a substantially cuboid shape. In the examples of FIG. 1, all output means 160 are substantially the same. However, in other examples, not all output means such as output means 160 may be substantially the same. To the contrary, output means such as output means 160 may differ in size and shape. Sizes and shapes may be varied to increase comfort for the person on which the applicator is used. For example, output means may differ in their length, e.g. one or more output means in the center of the plurality of output means may have a shorter length than one or more output means at a periphery of the output means, such as to adapt to an expected spherical surface of a scalp.

[0089] Output means 160 may be arranged to be placed on a surface of a target, e.g. a surface of a scalp. Applicator 100 may comprise an essentially plane lower surface from which each output means 16o protrudes. Output means 160 may comprise a width (understood here with respect to the drawing plane of FIG. 1) in the range of 0.01 centimeter to 2 centimeters, preferably in the range of 0.02 centimeters to 1.5 centimeters, more preferably in the range of 0.05 centimeters to 1 centimeter, most preferably in the range of 0.1 centimeters to 0.5 centimeters. Furthermore, output means may comprise a length in the range of 0.2 centimeters to 10 centimeters, preferably in the range of 0.3 centimeters to 5 centimeters, more preferably in the range of 0.5 centimeters to 3 centimeters, most preferably in the range of 1 centimeter to 2.5 centimeters.

[0090] Output means 160 are arranged such that hair can be accommodated at least partly in between them. In the example of FIG. 1, output means 160 define three-dimensional voids 170 in between them to this end. That is, voids 170 are sized as to accommodate hair at least partly. Just as output means 160 themselves, voids such as voids 170 do not need to be the same. Rather, voids such as voids 170 may differ in size and shape. For example, the width (understood here with respect to the drawing plane of FIG. 1) of voids 170 may be in the range of 0.01 centimeter to 10 centimeters, preferably in the range of 0.02 centimeters to 5 centimeters, more preferably in the range of 0.05 centimeters to 2 centimeters, most preferably in the range of 0.1 centimeters to 1 centimeter. The width of voids 170 may correspond to a (average) distance between outer surfaces of two adjacent (e.g., next neighbor) output means 160. Similarly, a height (understood here with respect to the drawing plane of FIG. 1) of voids 170 may correspond to a (average) length of output means 160. For example, a height may be in the range of 0.2 centimeters to 10 centimeters, preferably in the range of 0.3 centimeters to 5 centimeters, more preferably in the range of 0.5 centimeters to 3 centimeters, most preferably in the range of 1 centimeter to 2.5 centimeters.

[0091] Output means 160 may be adapted such that laser light is output with a predetermined diameter onto a surface of a target if the applicator is placed onto the surface. In some examples, the laser light may be output as a diverging beam (as shown in FIG. 1). Thus, it may be avoided that the power density applied is too high in case the applicator is incorrectly placed further away from the target than intended by placing it onto the surface of the target. In other examples, a collimated beam may be output.

[0092] Output means 160 may comprise output lenses 162. Output lenses 162 may focus partial laser beams 120 that are obtained from the laser beam strips (details below in the context of FIGS. 2 and 3). Output lenses 162 may also be adapted to collimate partial laser beams 120. In the example of FIG. 1, output lenses 162 are placed closer towards a proximal end of output means 160, i.e., closer to an end through which partial laser beams 120 pass first. In other examples, output means such as output means 160 may each comprise more than one output lens like output lenses 162, or none at all. Also, output lenses such as output lenses 162 may be placed closer towards a distal end of output means 160, i.e., closer to an end through which partial laser beams 120 pass last. Additionally or alternatively, each output means 160 may comprise a window, e.g., at their respective distal ends. This may provide for a well-defined positioning of the output means 160 on the surface of the target and at the same time avoid particles, e.g. dust or dirt particles, from entering the output means 160. The window may be selected from materials that are at least partially transparent to infrared or near-infrared laser wavelengths. These materials can different plastic or thermoplastic polymers, such as polypropylene, polyethylene, polytetrafluoroethylene or similar; or different glass materials, such as, for example sapphire glass or fused quartz glass.

[0093] FIG. 2 shows another example of an applicator 200 according to the present invention. Applicator 200 receives a—possibly collimated—laser beam 210 and (re)directs laser beam 210 towards reflective means 240 comprising mirror segments 242 and 244. In these respects, applicator 200 may be considered to be similar to applicator 100, such that the above explanations also apply to applicator 200.

[0094] Applicator 200 comprises at least two output means 260. Output means 260 each comprise a core 261 (labelled collectively in FIG. 2) as well as a cover 269 that is releasably attached or attachable, respectively, to applicator 200 and/or cores 261, respectively. In the example of FIG. 2, output means 260 comprise a single, unitary cover 269. In other examples, output means such as output means 260 may comprise a cover 269 consisting of individual portions. For example, a cover such as cover 269 may comprise as many individual portions as there are cores such as cores 261. In the example of FIG. 2, only cores 261 may be adapted to guide partial laser beams (not shown). For example, cores 261 may comprise a hollow waveguide and/or an optical fiber. In contrast, cover 269 may not be adapted to guide partial laser beams, e.g., cover 269 may be opaque with respect to visible light and/or (partial) laser beams. In other examples, also cover 269 may be adapted to guide partial laser beams.

[0095] In the example of FIG. 2, cover 269 comprises elongated elements, each adapted to cover a single core 261. The elongated elements comprise a substantially cylindrical shape with a thickened distal end, wherein the distal end of the elongated elements as well as a distal end of cover 269 is defined such that it coincides with the distal end(s) of output means 260 as defined above for output means 160 (being an end through which partial laser beams such as partial laser beams 120 pass last). However, generally, in other examples the shape of such elongated elements and/or a cover such as cover 269 as a whole may be adapted to the shape and size of cores such as cores 261 or to the shape and size of output means such as output means 260 more generally. The thickened distal ends may comprise a different material than a rest of cover 269. For example, the thickened distal ends may comprise a soft material in order to increase comfort for a person on which applicator 200 is used. The distal ends of cover 269 may comprise an optical element, e.g. a transparent window and/or an output lens, which may be adapted to seal the distal ends.

[0096] Having output means such as output means 260 comprise a cover such as cover 269 may be advantageous for hygiene reasons. For example, after contact with a person's skin, such a cover may easily be removed, cleaned, possibly disinfected and reused, or it may be replaced with a new, possibly sterile, one.

[0097] Applicator 200 may comprise lenses 250. In the example of FIG. 2, lenses 250 are placed right above (upstream with respect to the course of the laser light) output means 260 and below (downstream) reflective means 240. In terms of the optical path of laser beam 210, lenses 250 sit between mirror segments 242 and 244 and output means 260. Each lens 250 may be arranged atop a single output means 260, i.e., one lens 250 corresponds to one output means 260. Lenses 250 may not be arranged contiguously. Instead, they may be arranged in rows that extend perpendicularly to the direction of incoming laser beam 210. In each row, there may be gaps between lenses 250. These gaps may for example be defined by a lower outer wall of applicator 200. The lower outer wall of applicator may be opaque with respect to visible light and/or (partial) laser beams. Hence, the optical path for portions of laser beam 210 impinging thereon is blocked. There may also be gaps between adjacent rows. However, reflective means 240 may be adapted such that essentially the entire incoming laser beam 210 is redirected onto the rows of lenses 250 with essentially no light impinging on the gaps between the rows.

[0098] In the example of FIG. 2, laser beam 210 is (re)directed onto reflective means 240.

[0099] Reflective means 240 splits laser beam 210 into a number of laser beam strips that propagate in a direction that is substantially perpendicular to the direction from which laser beam 210 is initially received, similar as described with respect to laser beam 110 and reflective means 140 of FIG. 1. The laser beam strips impinge on (the rows of) lenses 250 (and the gaps formed between lenses 250 in each row). As the gaps—or the lower outer wall of applicator 200, respectively—are opaque with respect to visible light and/or (partial) laser beams, i.e., block their optical path, the portions of the laser beam strips that impinge onto the gaps do not propagate further, at least not along the direction in which they arrive. Instead, they may be absorbed by the gaps. In contrast, those portions of the laser beam strips that impinge on lenses 250 are guided into output means 260. In the example of FIG. 1, there is a one-to-one correspondence between lenses 250 and output means 260. Preferably, lenses such as lenses 250 are arranged to correspond to reflective means such as reflective means 240. Here, mirror segments 242 and 244 as well as lenses 250 are sized and arranged such that the laser beam strips impinge on corresponding rows of lenses 250, wherein these rows of lenses 250—just as mirror segments 242 and 244—extend essentially perpendicularly to the drawing plane. However, generally, lenses such as lenses 250 may be arranged in any, arbitrary pattern.

[0100] FIG. 3 shows another example of an applicator 300 according to the present invention. Applicator 300 receives a laser beam 310 and (re)directs laser beam 310 towards a reflective means 340 comprising mirror segments 342 and 344. In these respects, applicator 300 may be considered to be similar or even identical to applicator 200 (and by that virtue also similar to applicator 100), such that the above explanations also apply to applicator 300.

[0101] Different from applicator 200, applicator 300 comprises output means 360 (labelled collectively) that are as a whole releasably attached or attachable, respectively, to applicator 300 (as opposed to output means 260 of the example of FIG. 2, of which only a portion, i.e., cover 269, is releasably attached or attachable, respectively, to applicator 200 and/or cores 261, respectively). For example, this may enable to provide applicator 100 with output means 360 of different lengths, e.g. allowing to adapt to different targets, e.g. targets with longer and/or thicker hair or targets with shorter and/or thinner hair.

[0102] In some examples, output means such as output means 360 may be releasably attached or attachable, respectively, on an individual basis, i.e., each output means such as output means 360 may be releasably attached or attachable, respectively, independently of other output means 360. In some examples, only some of output means such as output means 360 may be releasably attached or attachable, respectively, either collectively or individually. In yet other examples, none of output means such as output means 360 may be releasably attached or attachable, respectively, neither as a whole nor in portions.

[0103] Just as output means 160 of the example of FIG. 1 and output means 260 of the example of FIG. 2, output means 360 are identical in shape and size, but may differ from each other in other examples. For example, the shape and the size, but also the materials of output means 360 may be adapted to provide an increased level of comfort for the person on which applicator 300 is used. For example, they may comprise soft materials and/or may be flexible and/or elastic. Output means 360 may be spacer tubes, i.e., they may consist of a substantially cylindrical outer wall only. But output means 360 may also comprise hollow waveguides or optical fibers. Possibly, output means 360 may also comprise cores (not shown) similar to cores 261 of the example of FIG. 2 which in turn comprise hollow waveguides and/or optical fibers, while also comprising spacer tubes that are arranged around the cores, similar to how cover 269 covers cores 261 in the example of FIG. 2. The skilled person will readily understand that the above may apply to all and any output means discussed herein throughout.

[0104] In another example, the proximal end of at least one, more than one but not all, or all of the output means may be attached to and/or enclosed by a base surface comprising flexible and/or (visco) elastic properties, such as a polymer foam or similar. In yet another example, cover 269 may be attached onto such a base surface comprising flexible and/or (visco) elastic properties. This may enable better adaptation of the output means, e.g., to a scalp shape and therefore a more comfortable procedure.

[0105] FIG. 4 shows a schematic top and/or bottom view, respectively of output means 460 (not all labelled individually) of an applicator according to the present invention. Notably, for the purposes of the schematic view of FIG. 4, output means 460 may be equated to partial laser beams 420 (not all labelled individually). Output means 460 may be arranged in columns 465a-465e, wherein within each column, the output means may be arranged equidistantly. Columns 465a and 465e comprise fewer output means than columns 465b-465d. Yet, columns 465a and 465e are arranged such that output means 460 comprised therein align with output means 460 comprised in columns 465b-465d. Accordingly, output means 460 are not only arranged in in columns 465a-465e, but simultaneously also in rows, wherein these rows are essentially perpendicular to columns 465a-465e. Overall, the arrangement of output means 460 is therefore symmetric, in particular mirror symmetric. The skilled person will readily understand that partial laser beams 420 may accordingly be applied in a corresponding pattern of columns and rows that are essentially perpendicular to each other. The skilled person will also readily understand that the arrangement of output means 460 illustrated in FIG. 4 is purely exemplary and that other, different arrangements are also possible within the meaning of the present invention. For example, any two-dimensional lattice structure may be used, i.e., output means such as output means 460 may be arranged in a rhombic lattice, square lattice, hexagonal lattice, rectangular lattice, parallelogrammical lattice or triangular lattice.

[0106] Again, the skilled person will readily understand that partial laser beams such as partial laser beams 420 may then accordingly be applied in a corresponding pattern, i.e., lattice structure. The skilled person understands that this correspondence between arrangement of output means and arrangement of applied partial laser pulses applies throughout the entire present disclosure.

[0107] FIG. 5 shows a schematic top and/or bottom view of partial laser beams 520 as they may be applied by output means of an applicator 500 (not shown) according to the present invention. The arrangement of output means applying the shown arrangement of partial laser beams 520 may in general be similar to the one shown in FIG. 4, however with one output means less in every column, such as to correspond to the arrangement of partial laser beams 520 shown in FIG. 5. Notably, partial laser beams 520 may be applied by output means 260 of FIG. 2 or output means 360 of FIG. 3, for example.

[0108] Accordingly, partial laser beams 520 are applied in columns 565a-565e. In the example of FIG. 5, columns 565a and 565e comprise two partial laser beams 520, while columns 565b-565d comprise four partial laser beams. Within each column, partial laser beams 520 are spaced apart a distance l. All partial laser beams 520 comprise an average diameter D. l and D are rational numbers, preferably positive rational numbers. Again, just as laser beams such as laser beams 110, 210 and 310, partial laser beams such as partial laser beams 120, 420 and 520 may comprise a cross section of any shape, e.g., a square, rectangular, elliptic or hexagonal shape. Only for convenience and simplicity, the discussed examples comprise laser beams and partial laser beams of a circular cross section.

[0109] Columns 565b and 565c as well as 565c and 565d may be spaced apart a distance L.sub.1.L.sub.1 is a rational number approximately given by

[00007]$4\frac{D}{\sqrt{1-D^2/l^2}}$

(details below).

[0110] Columns 565a and 565b, and columns 565d and 565e are spaced apart a distance L.sub.2.L.sub.2 is a rational number approximately given by

[00008]$3\frac{D}{\sqrt{1-D^2/l^2}}$

(details below).

[0111] As illustrated in FIG. 5, each partial laser beam 520 may be associated with a track 525 (not all labelled). Tracks 525 each denote a respective area to which the respective partial laser beam is applied if applicator 500 is moved along direction 505. As illustrated, direction 505 may be defined by an angle α with respect to the dimension along which columns 565a-565e extend. In other examples, direction 505 may be defined by an angle with respect to the dimension along which columns 565a-565e extend in the range of 0.5α to 1.5α, preferably 0.8α to 1.2α, more preferably 0.9α to 1.1α, most preferably 0.95α to 1.05α. It holds

[00009]$\sin \alpha =\frac{D}{l}.$

α may be any angle between 0° and 90°.

[0112] As can be seen, the angle may be selected such that tracks 525 may join (approximately) seamlessly, i.e., the total area to which partial laser beams 520 are applied when applicator 500 is moved along direction 505 is contiguous. At the same time, tracks 525 do not overlap. As such, the arrangement of output means underlying the pattern of partial laser beams 520 of FIG. 5 yields a perfectly even and seamless application of partial laser beams 520. Therefore, direction 505 may be considered a preferred direction of movement.

[0113] Direction 505 may be indicated (e.g. on the applicator) such that it is perceivable by a user at least while applicator 500 is in use. For example, direction 505 may be printed onto applicator 500, for example on a backside of applicator 500, or onto any other side with no output means arranged thereon. In other examples, direction 505 may be indicated on a display, e.g., on a computer monitor or a similar digital display, which may either be arranged at applicator 500 or remote therefrom. In yet other examples, direction 505 may be indicated by means of haptic feedback. For example, applicator 500, or at least a handle thereof, could be caused to vibrate in order to notify the user whether he/she is moving applicator 500 along direction 505.

[0114] The above factors

[00010]$4\frac{D}{\sqrt{1-D^2/l^2}}\mathrm{and}3\frac{D}{\sqrt{1-D^2/l^2}},$

respectively, may be derived as follows: Let ΔL denote a width of a horizontal cut through a single track 525. Horizontal is to be understood with respect to the drawing plane of FIG. 5. Horizontal may additionally or alternatively be understood as perpendicular to the direction along which columns 565a-565e extend. Notably, ΔL may be different from a width of a track 525, which may be assumed to be given by the average diameter D of a partial laser beam associated with the track 525 as indicated in FIG. 5. A relationship between ΔL and D may be given by

[00011]$\cos \alpha =\frac{D}{\Delta L},$

wherein

[00012]$\sin \alpha =\frac{D}{l}$

as above. Recasting this,

[00013]$\Delta L=\frac{D}{\cos \alpha }$

may be obtained. As is well known, sin.sup.2α+cos.sup.2 α=1, i.e., cos α=√{square root over (1−sin.sup.2α)}. Substituting

[00014]$\sin \alpha =\frac{D}{l},\cos \alpha =\sqrt{1-D^2/l^2}$

may be obtained. Exploiting this,

[00015]$\Delta L=\frac{D}{\sqrt{1-D^2/l^2}}$

may be obtained.

[0115] Now to reach the center of a partial laser beam of, e.g., column 565d starting from the center of a corresponding laser beam of, e.g., column 565c, one must traverse approximately the distance L.sub.1, or approximately 4 times ΔL. Hence,

[00016]$L_1=4\frac{D}{\sqrt{1-D^2/l^2}}.$

[0116] Similarly, to reach the center of a partial laser beam of, e.g., column 565e from the center of a corresponding laser beam of, e.g., column 565d, one must traverse approximately the distance L.sub.2, or approximately 3 times ΔL. Hence,

[00017]$L_2=3\frac{D}{\sqrt{1-D^2/l^2}}.$

In this context, partial laser beams of different columns may be said to correspond if they may be arranged in a single row that extends perpendicular to the columns.

[0117] The pattern of partial laser beams 520 of diameter D shown in FIG. 5, if understood as a pattern of points which each correspond to the center of a respective partial laser beam 520, is an example of a pattern that may be obtained, from a column of points with an average distance l between the points, by translating one or more of the points of the column along a direction having an angle α with respect to the column, wherein

[00018]$\sin \alpha =\frac{D}{l}.$

α may be any angle between 0° and 90°. Adjacent columns obtained in this manner may then approximately be spaced apart a distance L given by

[00019]$\sin \alpha =\frac{D}{l}$

times the distance by which the respective points have been translated along the direction having the angle α with respect to the column.

[0118] Arranging output means of an applicator such as applicator 500 in a manner to provide such a pattern of partial laser beams such as partial laser beams 520 ensures that tracks such as tracks 525 join seamlessly, however without overlapping. That is, arranging output means of an applicator such as applicator 500 in a manner to provide such a pattern of partial laser beams such as partial laser beams 520 ensures that partial laser beams such as partial laser beams 520 cover a target area evenly and seamlessly, i.e., the area on which partial laser beams such as partial laser beams 520 impinge is contiguous.

[0119] FIG. 6 shows another example of an applicator 600 according to the present invention. Applicator 600 receives a laser beam 610, expands it using beam expanding means 630—a pair of beam-expanding lenses, one (bi)convex, on (bi)concave—and (re)directs laser beam 610 towards reflective means 640. In this respect, applicator 600 may be considered to be similar to, e.g., applicators 100, 200 and 300 of FIGS. 1, 2 and 3, respectively, such that the above explanations also apply to applicator 600.

[0120] However, different from applicators 100, 200 and 300 of FIGS. 1, 2 and 3, respectively, and their respective reflective means 140, 240 and 340, reflective means 640 may not comprise mirror segments such as mirror segments 142, 144, 242, 244, 342, 344. Instead, reflective means 640 may comprise a flat mirror. Reflective means 640 is angled with respect to the direction from which laser beam 610 is initially received by an angle of substantially 45°, but it is also possible to arrange reflective means 640 at an angle in the range of 20° to 70°, 30° to 60° or 40° to 50° with respect to the direction from which laser beam 610 is initially received, for example. Hence, reflective means 640 (re)directs laser beam 610 by substantially 90°, i.e., reflective means 640 (re)directs laser beam 610 such as to propagate in a direction that is substantially perpendicular to the direction from which laser beam 610 is initially received. As reflective means 640 does not comprise mirror segments such as mirror segments 142, 144, 242, 244, 342, 344 of FIGS. 1, 2 and 3, respectively, laser beam 610 is not split into laser beam strips, either.

[0121] After being (re)directed by reflective means 640, laser beam 610 impinges on an array of lenses 650. In principle, lenses 650 could be similar to lenses 250 and 350 of FIGS. 2 and 3, respectively. However, to avoid power loss due to gaps in between lenses 650, lenses 650 may be adapted to be hexagonal, as will be described in greater detail in the context of FIG. 8 (see below). Lenses 650 split laser beam 610 into at least two partial laser beams 620. In fact, lenses 650 may split laser beam 610 in as many partial laser beams 620 as there are lenses 650.

[0122] Partial laser beams 620 are guided into output means 660. There may be as many output means 660 as there are lenses 650 and partial laser beams 620. Regarding the shape and size of output means 660 as well as regarding their further characteristics, such as their material composition, it is referred to the above explanations concerning output means 160, 260 and 360 of FIGS. 1, 2 and 3, respectively, which apply to output means 660 equally.

[0123] In particular, also output means 660 are arranged such that hair can be accommodated at least partly in between them. That is, output means 660 define three-dimensional voids 670 in between them. Voids 670 are sized as to accommodate hair at least partly. Just as output means 660 themselves, voids 670 do not need to be the same. Rather, voids 670 may differ in size and shape.

[0124] FIG. 7 shows a further example of an applicator 700 according to the present invention. Applicator 700 receives a laser beam 710. Applicator 700 may be constructed identically to applicator 600, such that the corresponding explanations apply to applicator 700, as well. Therefore, reflective means may be considered to be identical to reflective means 640, and output means 760 may be considered to be identical to output means 660, such that also in this respect the above explanations apply.

[0125] As can be gathered from FIG. 7, voids such as voids 670 do not need to extend up to the point where laser beam 710 is split into partial laser beams such as partial laser beams 620. To the contrary, in the example of FIG. 7, lenses 750 (not shown) may be arranged at a proximal end of a common base block 768, i.e., at an end of common base block 768 through which partial laser beams such as partial laser beams 62o pass first. Hence, the partial laser beams are created at the proximal end of common base block 768. However, the voids (not labelled) formed between output means 760 may only extend, e.g., up to the distal end of common base block 768. In the example of FIG. 7, common base block 768 comprises a substantially cylindrical shape. On other examples, common base blocks such as common base block 768 may comprise different shapes, e.g., an elliptical cylindrical—such as in the examples of FIGS. 2 and 3 (not labelled there)—or a prism shape. Essentially, the output means 760 protrude from a lower (essentially flat) surface of applicator 700, which may coincide with the lower surface of common base block 768 in the example shown.

[0126] In other examples, lenses 750 may also be arranged at a distal end of a common base block such as common base block 768, i.e., at an end of the common base block through which a laser beam such as (re)directed laser beam 710 passes last. Then, the common base block 768 may function like an aperture.

[0127] FIG. 8A shows a schematic top and/or bottom view of a plurality of lenses 850 of an example of an applicator according to the present invention. In principle, lenses 850 may correspond to lenses 650 of applicator 600 of FIG. 6, such that the following explanations may apply to the applicator 600 of FIG. 6, as well. Lenses 850 are hexagonal lenses.

[0128] Moreover, lenses 850 are arranged in a contiguous manner. As shown in FIG. 8A, lenses 850 almost completely cover, or “tile”, a cross section 815 of a laser beam that impinges on lenses 850. In principle, said laser beam may correspond to laser beam 610, e.g., after it is (re)directed by reflective means 640. Hence, contiguous hexagonal lenses 850 may allow for a high degree of efficiency, i.e., an amount of energy that is lost when splitting the laser beam into partial laser beams by virtue of lenses 850 is minimized.

[0129] FIG. 8B shows a schematic top and or bottom view of partial laser beams 820 applied by output means of an example of an applicator according to the present invention. Partial laser beams 820 may be applied by an applicator employing a plurality of hexagonal lenses such as lenses 850 of FIG. 8A. Centers of partial laser beams 820 may correspond to centers of hexagonal lenses such as lenses 850 that were used in obtaining partial laser beams 820.

[0130] The skilled person will understand from the above explanations that the various means discussed herein do not need to be implemented as a single element each. In some examples, certain means may be implemented by a plurality of elements that may or may not simultaneously function as other means or parts thereof, too. For example, while in the example of FIG. 6 lenses 650 may be regarded as means for splitting laser beam 610, in the examples of FIGS. 2 and 3 at least mirror segments 244 and 344 together with lenses 250 and 350, respectively, may be regarded as means for splitting laser beam 210 and 310, respectively, although mirror segments 244 and 344 additionally also form part of reflective means 240 and 340, respectively. Yet, one may also solely regard lenses 250 and 350 as means for splitting. Similarly, amongst other things, lenses functioning as means for splitting a laser beam such as lenses 250, 350 or 650 may simultaneously also function as output lenses of output means such as output lenses 162 of output means 160 of the example of FIG. 1.

[0131] It is emphasized again that the skilled person will readily understand that all the means discussed herein, including the means for splitting at least one laser beam, may be arranged in any order and combination thanks to the reversibility of optical paths.

[0132] The skilled person also understands that wherever reference is made to a definite geometrical relation the respective expressions should be understood to also mean relations that are substantially equal to the definite geometrical relation explicitly referred to, i.e., “perpendicular” should be understood to mean “essentially perpendicular”, “angled at 45°” should be understood to mean “angled at substantially 45°”, and so forth.

[0133] A method for hair scalp regeneration according to the current invention (e.g., for ameliorating alopecia, for improving quality, color and/or density of hair, and/or for improving a condition of a scalp) may comprise any one, two or three of the following three steps either performed separately or as a combination of any of the three steps in any order of succession.

Step 1: Non-Ablative Thermal Stimulation

[0134] In one of the embodiments, this step is performed with an Erbium laser with a wavelength between 2.5 and 3.5 μm, such as for example Er:YAG (2940 nm) or Er, Cr:YSGG (2780 nm). The laser energy is delivered in a pulse train sequence consisting of N subablative laser pulses where N=1-100, preferably N=5-40 separated by pulse separation time t.sub.ser=5-500 ms, preferably t.sub.ser=20-250 ms, and characterized by one or more (or all) single laser pulse durations of less than 5 ms, preferably less than 1 ms, and one or more (or all) single pulse fluences F.sub.o below 2.5 J/cm.sup.2, preferably below 1 J/cm.sup.2, most preferably below 0.5 J/cm.sup.2. The cumulative fluence F.sub.c=N×F.sub.o is for N greater than 1 in the range of 1-50 J/cm.sup.2, preferably up to 20 J/cm.sup.2 with overall pulse sequence duration t.sub.c=N×t.sub.ser being in the range of 20 ms to 10 s, preferably in the range of 100 ms−2000 ms. The combination of parameters N, F.sub.o and t.sub.ser must be chosen such that the pulse sequence does not result in an appreciable tissue ablation.

Step 2: Ablative Resurfacing

[0135] Ablative resurfacing may be performed in order to produce small epidermal perforations. The goal of these perforations is to trigger scalp regeneration via tissue healing mechanisms, and/or to facilitate penetration of PRP (Platelet-Rich Plasma) or any other medications intended for the treatment of hair loss and other scalp related indications. For example, the medications may be applied by simply rubbing them thoroughly in, for example, circular motion over the pre-drilled area.

[0136] In one of the embodiments this step is performed with an Erbium laser with a wavelength between 2.5 and 3.5 mm, such as for example Er:YAG (2940 nm) or Er, Cr:YSGG (2780 nm). The laser energy may be delivered in N=1-10 pulses separated by t.sub.ser=20-500 ms, preferably t.sub.ser=50-250 ms, and characterized by one or more (or all) single laser pulse durations of less than 5 ms, preferably less than 1 ms, and one or more (or all) single pulse fluences F.sub.o above 2 J/cm.sup.2, preferably above 5 J/cm.sup.2, most preferably above 8 J/cm.sup.2.

Step 3: Biomodulation

[0137] Biomodulation may consist of non-ablative non-thermal (average power density less than 0.2 W/cm.sup.2) or minimally thermal (average power density less than 3 W/cm.sup.2) stimulation of the scalp.

[0138] In one of the embodiments, minimally thermal stimulation is performed with an Nd:YAG laser (1064 nm) with an average power density below 3 W/cm.sup.2, preferably below 0.5 W/cm.sup.2. The treatment duration may be adjusted from 0.5 s to 5 s to deliver from 0.1 J/cm.sup.2 to 1.5 J/cm.sup.2.

[0139] Other preferred embodiments include the following diode lasers, with the treatment duration adjusted from 0.5 s to 5 s to deliver from 0.1 J/cm.sup.2 to 1.5 J/cm.sup.2; 1064 nm diode with power density below 0.5 W/cm.sup.2 preferably below 0.2 W/cm.sup.2; 630-680 nm diode with power density below 0.3 W/cm.sup.2 preferably below 0.1 W/cm.sup.2; 960-980 nm diode with power density below 0.3 W/cm.sup.2 preferably below 0.2 W/cm.sup.2.