WO2018005323A1

WO2018005323A1 - Apparatus and method for fractional light treatment

Info

Publication number: WO2018005323A1
Application number: PCT/US2017/039199
Authority: WO
Inventors: A. Jason Mirabito; Assaf Gelstein
Original assignee: Lumenis Ltd.
Priority date: 2016-06-29
Filing date: 2017-06-26
Publication date: 2018-01-04
Also published as: IL263151A; CA3026179A1; EP3478203A4; EP3478203A1; CN109475383A

Abstract

A method of cosmetically treating skin tissue includes the steps of: providing a light source to direct one or more light energy beams to the skin tissue; providing a prism and interposing the prism between the light source and the skin tissue; activating the light source. The one or more light energy beams passing through the prism converge and are focused to one or more focal points at or near the skin tissue surface; and then each of the one or more light energy beams each diverge after passing through the one or more focal points to each create a plurality of microchannels in the skin tissue.

Description

APPARATUS AND METHOD FOR FRACTIONAL LIGHT TREATMENT

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/355,971, filed June 29, 2016. The entire contents of the foregoing disclosure are herein incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to apparatus and methods of performing fractional light treatments to human skin and other tissue.

BACKGROUND OF THE INVENTION

Fractional light treatment of the skin has been known for some time and commercial products are available in the marketplace that perform fractional skin treatments. These treatments may be light-based but also may be RF or ultrasonic (UL)-based and in addition may be of a non-ablative, coagulation type or an ablative type, both of which types are described in US 8,496,696, assigned to the assignee of the present invention.

Prior to fractional treatment, rather than selected microchannels being "drilled" into the skin tissue, large portions of skin tissue were ablated, causing pain to the patient and sometimes long recovery times. These are described in the above patent US 8,496,696, particularly in col.l, line 34 to col. 3, line 20. Fractional treatment decreases both the level of pain experienced and the recovery time, but these remain concerns in certain circumstances.

Typically, in a fractional treatment, a plurality of spaced apart light beams impinges on the skin surface and, depending on whether the energy supplied is for non-ablative or ablative treatment, areas of the skin are heated but surrounded by unheated areas (non-ablative) or microchannels are formed in the skin and penetrate to a determined depth into the skin surface, but again, these microchannels are surrounded by areas of non-treatment. Thus, the term

"fractional" has the meaning that a "fraction" of the skin surface is treated with non-ablative, ablative or a combination of non-ablative light energy.

Generally, and concentrating on the ablative technique while the same rationale applies to non-ablative, light beams are delivered to the skin surface as generally parallel beams, such that the microchannel formed are generally parallel to one another within the skin surface. The delivery system may be a lens system which splits the light beam, generally from a laser device, into a number of parallel light beams before it reaches the skin surface. US Patent Publication No. 2006/0004347 is one example of such an approach. Another approach is to use a mirror and galvometric motor systems distal of the laser light beam to direct the laser beams onto a number of rows and columns on the skin surface in seriatim. US Patent Nos. 5,743,902; 5,957,915; 6,328,733 typify such a so-called laser scanning system.

A potential problem with either of the above approaches is that there is one microchannel for each laser light beam that penetrates the skin surface and this potentially exposes the patient to a longer-term recovery due to the number of microchannels and the potential possibility of infection simply due to the number of microchannels drilled into the skin surface.

Thus, there is a perceived need for a fractional device which forms fewer microchannels in the skin surface yet under the skin surface multiplies into a greater number of microchannels. It is to this need that the present invention is addressed.

SUMMARY OF THE PRESENT INVENTION

In an aspect, a method of cosmetically treating skin tissue includes the steps of: providing a light source to direct one or more light energy beams to the skin tissue; providing a prism and interposing the prism between the light source and the skin tissue; activating the light source; the one or more light energy beams passing through the prism converge and are focused to one or more focal points at or near the skin tissue surface; each of the one or more light energy beams each diverge after passing through the one or more focal points to each create a plurality of microchannels in the skin tissue. The light source may be one of: coherent or incoherent light.

In another aspect, the prism is a pyramidal prism having an apex and a base and wherein the one or more light energy beams are positioned to pass through the pyramidal prism in the direction from the apex and through the base of the prism. The pyramidal prism may include 3 or more prism surfaces and may be a flat-top pyramidal prism.

In a further aspect, the number of diverging light beams is correlated with the number of prism surfaces. The prism may be two or more prisms, the two or more prisms being arranged on their bases arranged adjacent to one another on a plane. The diverging light beams may produce one or more of: ablative or coagulative effects in the skin tissue. In another aspect, the plurality of prisms may be arranged as an array of microlenses mounted in a tube having a distal portion and a proximal portion, the array being mounted in the distal portion and the light energy being received from the proximal portion to travel through the tube and to the distal portion. The method further may include the steps of placing the distal portion of the tube in contact with the skin tissue and activating the light energy to pass through the tube, through the array and into the skin tissue.

In another aspect, the one or more diverging light beams produce a fractional effect in the skin tissue. Further, the angular orientation of the pyramidal surfaces to the base determines the angle of the diverging light energy beams. The angular orientation of the light energy impinging on the pyramidal surfaces determines the angle of the diverging light energy beams. The method may further include the step of interposing a heat absorbing material between the base of the prism and the skin tissue.

In an aspect, a device for cosmetically treating skin tissue includes: a light source to direct one or more light energy beams to the skin tissue; a prism, the prism being interposed between the light source and the skin tissue; when the light source is activated, the one or more light energy beams pass through the prism, become converged and are focused to one or more focal points at or near the skin tissue surface; and, wherein each of the one or more light energy beams each diverge after passing through the one or more focal points to each create a plurality of microchannels in the skin tissue. The light source may be one of: coherent or incoherent light.

In a further aspect, the prism is a pyramidal prism having an apex and a base and wherein the one or more light energy beams are positioned to pass through the pyramidal prism in the direction of from the apex and through the base of the prism. Further, the pyramidal prism may include 3 or more prism surfaces. Also, the pyramidal prism may be a flat-top pyramidal prism. The number of diverging light beams is correlated with the number of prism surfaces.

In yet a further aspect, the prism may comprise two or more prisms, the two or more prisms being arranged on their bases arranged adjacent to one another on a plane. Further, the diverging light beams produce one or more of: ablative or coagulative effects in the skin tissue. The plurality of prisms may be arranged as an array of microlenses mounted in a tube having a distal portion and a proximal portion, the array being mounted in the distal portion and the light energy being received from the proximal portion to travel through the tube and to the distal portion.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 illustrates a perspective view of a prism structure in accordance with the present invention.

Fig. 2 illustrates a side interior view of light beams passing through the prism of Fig. 1.

Fig. 3 illustrates further side interior and top views of light beams passing through a prism flat-top prism in accordance with the present invention.

Figs. 4 and 5 illustrate prism structures in the form of an array of microlenses.

Fig. 6 illustrates an array of microlenses mounted in a hollow tube or funnel-like structure.

Fig. 7 illustrates the interaction of a donut-shaped light source impinging on a prism similar to the prism of Fig. 3.

Fig. 8 illustrates a prism similar to those of Figs. 1 to 3 and further including an isolation layer of material interposed between the prism bottom surface and a patient's skin tissue.

Figs. 9A and 9B illustrate an array of Fresnel lenses mounted on a plate.

Fig. 10 illustrates a lens array mounted on a holding plate in accordance with the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention provides a solution to the potential problems described above by directing a number of laser light beams to impinge on the skin surface at a common point by being focused at or near (either above or below) the skin surface but then diverging to create a plurality of subsurface microchannels in the case of ablative treatment or areas of heating in the case of non-ablative heating. This treatment technique described in the present invention may become known as "3D Fractional" in that a single or several beam(s) are divided or scanned into multiple three-dimensional beam coverage within the patient's skin tissue.

One apparatus for performing this function is shown in Fig. 1. Fig. 1 illustrates a plurality of light beams 10 traveling more or less in a parallel fashion from a light source (not shown), which may be a laser light source of a known type. Prior to reaching the epidermis 12 of the skin, a prism 14 is interposed between the light beams 10 and the epidermis/skin surface 12. The purpose of the prism, shown in Fig. 1 as a pyramidal prism, is to redirect the light beams 10 striking the prism surfaces 16a, 16b, 16c, ...16n to a central focal point at the bottom flat surface of the prism just before (or even just after) the light beams enter into the epidermis.

Turning now to Fig. 2, this figure shows a side view of two exemplary beams 20 and 22 as they strike the surfaces 24 and 26 of the prism after traveling through the air. As illustrated, the light beams 20 and 22 will be bent upon striking the prism surface according to the well- known Snell's law. By adjusting the angular orientation of the prism sides with respect to the base of the prism, shown in Fig. 2 as angle a2, the beams hitting prism at points 28 and 30 will be refracted/deflected in a way so that they converge just above, at or below point 33 on the base of the prism. The skin tissue penetration point depends on the angle the laser light beam(s) hit the prism' s side surface, the angle of the prism side surfaces with respect to the base of the prism and at which point or points along the prism side surface the laser light beam hits. These are all variables that can be controlled by a programmed controller in order to deliver the treatment desired. The skin surface is shown in Fig. 2 at 34. After impinging on the epidermis at 34, the beams will then begin to diverge from one another into the skin tissue 34A as can be seen in Fig. 2 as well as in Fig. 3 in which beams 31, 37 and 39 will converge at point 35 on the bottom surface of the prism and then diverge as beams 44, 46 and 48 respectively within the skin tissue 42. Once within the tissue, the beams, depending on the particular specifications of the beams 44, 46 and 48, will drill microchannels 36, 38 and 40 and/or areas of coagulation. Thus, one single area of the skin produces multiple channels/ areas of coagulation, thus reducing the disturbance of the epidermis skin surface.

As mentioned above, in prior art laser fractional devices, a single spot of light on the skin generates a single channel or area of coagulation. Each spot of light on the skin is characterized, among other things, by a certain spot area based on the beam characteristics known to those skilled in the art. In addition, the single channel or area of coagulation defines a certain volume in the skin directly affected by the laser beam, having a certain surface. Laser wavelength and other laser beam parameters affect this volume and therefore its surface. It is another aspect of the invention to increase these overall surfaces with a single spot of light on the skin. It has been found that the larger the overall surface of the channels or area of coagulation in the skin, the better the clinical effect of skin rejuvenation as a result of a stronger healing response and stronger collagen production. However, the larger the overall area of spots of light on the skin, and the density of the affected tissue through which light penetrates into the skin to create these channels or areas of coagulation, the higher the risk for complications and the longer the time for the tissue to heal.

In prior art systems, in which a single channel or area of coagulation in the skin is generated per a single spot of light on the skin, in order to increase the number of channels or areas of coagulation in the skin and their surfaces, an increase in the area of the spot of light on the skin is required. Therefore, according to this aspect of the invention there is provided a system and method to increase the overall surface of the channels or areas of coagulation in the skin without the need to increase the areas of spot of lights on the skin. According to another aspect of the invention, at least one of the multiple channels or areas of coagulation has a main longitudinal axis which is not approximately perpendicular to the skin surface. According to this aspect of the invention, at least two channels or areas of coagulation are not parallel to one another. They define two separate volumes of tissue directly affected by a laser beam yet they share a common spot on the skin through which a laser beam penetrates the skin. In addition, in the present invention, the utilization of a combination of ablative and non-ablative coagulation treatments may be "custom blended" to achieve the desired results in the 3D volume of tissue affected by the impingement of light (or RF energy or UL energy) on the tissue.

Any number of beams may be utilized depending on the number of sides that the prism possesses. As seen in Fig. 3, the prism may be a flat-topped pyramidal prism so that a center beam goes through the prism un-refracted or un-bent, as with beam 37. The prism may be placed directly on the epidermis or may be mounted or fixed a predetermined distance from the skin surface, as desired, with the angles of the prism sides with respect to the base being adjusted so the beams become focused at the epidermis surface. In addition, it may be desirable to provide that the beams 31, 37 and 39 are focused not at the surface but below or even above the skin surface. The prism may be placed or mounted within a housing open at the top and bottom with active or passive cooling of the housing that will cool the prism and thus the patient's skin.

Figs. 4 and 5 illustrate the application of the principles of the prism structure of Figs. 1 to 3 as applied to microlens arrays, either in the form of triangular/trapezoid [not shown] microlenses or, as in Fig. 5, hexagonal shaped microlenses. Fig. 6 illustrates an array of microlenses 100 which may be like the arrays depicted in Figs. 4 or 5 mounted on a hollow tube or funnel. It is to be understood that the element 102 may be solid or may be an open framework. While the distal end 104 may be in contact or in the vicinity of the patient's skin tissue to be treated, the proximal end 106 may be in contact with or at least aligned with the laser source to be applied through the tube or funnel, through the array of prisms and into the patient's skin tissue. While shown as a conical shape, the element 102 may be any suitable shape. A device to evacuate smoke from tissue disruption by the laser, presently used in some C02 laser systems, may also be incorporated into the device 110. The device 110 may be either a disposable or not disposable depending on cost, ease of sterilization and other factors.

Fig. 7 illustrates another embodiment of the present invention in which a donut-shaped laser light beam 200 is impinged on a prism 202 which may be like the prisms in Figs. 1, 2 or 3. Once the light beams have impinged on prism 202, they are bent as shown and form in the skin a generally cone shaped ablation/coagulation volume of dimensions much greater than the initial contact or entry into the patient's skin surface 204.

Fig. 8 illustrates another embodiment of a device in which an isolation layer of suitable material 300 is interposed between the prism 302 and the patient's skin surface 304. The material 300 may be selected for transmissivity but also may have heat absorptive characteristics. The material 300 may be, for example, actively cooled with suitable means to keep the patient's skin tissue cool and may include a drug or other substance to enhance the clinical response or improve results of the treatment with the interposition of the material 300, as this arrangement will affect the focal point 306 due to the greater distance from the skin compared to when there is no material 300 present. Of course, the focal point can be manipulated by changing the angle (a 2 as in Fig.2) to cause deflection of the laser light beam and the focal point as desired.

Figs. 9A and 9B illustrate yet another embodiment in which an array of Fresnel lenses (like that shown as element 400 in Fig. 9A) are mounted on a plate or other holder 402 as micro Fresnel lenses 403a to 403n shown in Fig. 9B. These lenses are oriented as shown in Fig. 9A so that the parallel laser light beams are focused as desired on a patient's skin tissue 401 at one or multiple points. As with the other embodiments described in this application, the number of entries of laser light beams into the skin surface will be reduced to a lesser number than the treated areas, much like as shown in Figs. 1 and 2. Fig. 10 illustrates another embodiment of a lens array 500 which includes a plate or holder 502 which mounts or otherwise holds a number of microlenses 504a ... 504n which are oriented to converge light beams 506a to 506n onto a skin surface 508 at focal point 510.

Returning to Fig. 3, it is seen that a light beam 37 impinges the upper flat surface 43 of the flat-topped pyramid. As such, that beam 37 will travel through the prism undeflected. While all three beams 31, 37 and 39 may be of the same" type", that is, one of ablative or non-ablative, they may be "mixed and matched" so that, for example, the central beam 37 may be ablative while any side beams non-ablative or vice-versa, all dependent on the characteristics of the planned skin tissue treatment.

Also, while Figs. 1 to 3 illustrate the use of multiple parallel laser beams, a laser scanner of the type described above may be used to selectively impinge on desired sides of the prisms shown in a pattern to be selected dependent on the desired effects on the skin tissue.

Claims

WHAT IS CLAIMED IS:

1. A method of cosmetically treating skin tissue comprising the steps of:

providing a light source to direct one or more light energy beams to the skin tissue;

providing a prism and interposing the prism between the light source and the skin tissue; activating the light source;

wherein the one or more light energy beams passing through the prism converge and are focused to one or more focal points at or near the skin tissue surface; and,

wherein each of the one or more light energy beams each diverge after passing through the one or more focal points to each create a plurality of microchannels in the skin tissue.

2. The method of claim 1, wherein the light source is one of: coherent or incoherent light.

3. The method of claim 1, wherein the prism is a pyramidal prism having an apex and a base and wherein the one or more light energy beams are positioned to pass through the pyramidal prism in the direction of from the apex and through the base of the prism.

4. The method of claim 3 wherein the pyramidal prism includes 3 or more prism surfaces.

5. The method of claim 3, wherein the pyramidal prism is a flat- top pyramidal prism.

6. The method of claim 4 wherein the number of diverging light beams is correlated with the number of prism surfaces.

7. The method of claim 1, wherein the prism comprises two or more prisms, the two or more prisms being arranged on their bases arranged adjacent to one another on a plane.

8. The method of claim 1, wherein the diverging light beams produce one or more of:

ablative or coagulative effects in the skin tissue.

9. The method of claim 7, wherein the plurality of prisms is arranged as an array of microlenses mounted in a tube having a distal portion and a proximal portion, the array being mounted in the distal portion and the light energy being received from the proximal portion to travel through the tube and to the distal portion,

the method further comprising the steps of placing the distal portion of the tube in contact with the skin tissue and activating the light energy to pass through the tube, through the array and into the skin tissue.

10. The method of claim 1, wherein the one or more diverging light beams produce a

fractional effect in the skin tissue.

11. The method of claim 4, wherein the angular orientation of the pyramidal surfaces to the base determines the angle of the diverging light energy beams.

12. The method of claim 4, where the angular orientation of the light energy impinging on the pyramidal surfaces determines the angle of the diverging light energy beams.

13. The method of claim 3, further comprising the step of interposing a heat absorbing

material between the base of the prism and the skin tissue.

14. A device for cosmetically treating skin tissue, the device comprising:

a light source to direct one or more light energy beams to the skin tissue;

a prism, the prism being interposed between the light source and the skin tissue;

wherein, when the light source is activated, the one or more light energy beams pass through the prism, become converged and are focused to one or more focal points at or near the skin tissue surface; and,

15. The device of claim 14, wherein the light source is one of: coherent or incoherent light.

16. The device of claim 14, wherein the prism is a pyramidal prism having an apex and a base and wherein the one or more light energy beams are positioned to pass through the pyramidal prism in the direction of from the apex and through the base of the prism.

17. The device of claim 16, wherein the pyramidal prism includes 3 or more prism surfaces.

18. The device of claim 16, wherein the pyramidal prism is a flat-top pyramidal prism.

19. The device of claim 14, wherein the number of diverging light beams is correlated with the number of prism surfaces.

20. The device of claim 14, wherein the prism comprises two or more prisms, the two or more prisms being arranged on their bases arranged adjacent to one another on a plane.

21. The device of claim 14, wherein the diverging light beams produce one or more of:

ablative or coagulative effects in the skin tissue.

22. The device of claim 20, wherein the plurality of prisms is arranged as an array of

microlenses mounted in a tube having a distal portion and a proximal portion, the array being mounted in the distal portion and the light energy being received from the proximal portion to travel through the tube and to the distal portion.

23. A method of cosmetically providing fractional treatment to skin tissue, the method comprising:

providing an optical element;

placing the optical element directly or indirectly in contact with the skin tissue;

providing a source of light to provide one or more light energy beams;

activating the source of light to transmit the one or more light energy beams through the optical element and into the skin tissue;

wherein the optical element is shaped to receive the one or more light energy beams and cause the one or more light energy beams to be bent by the optical element and be converged and focused to a single focal point at or near the skin tissue surface; and, wherein the one or more light energy beams each diverge after passing through the single focal point to create a plurality of angled fractionated microchannels in the skin tissue below the skin tissue surface.

24. The method of claim 23, wherein the optical element is a prism with a flat bottom and three or more angled sides having a common apex, and wherein the flat bottom is placed in contact directly or indirectly with the skin tissue.

25. The method of claim 24, wherein a cooling substance is interposed between the flat bottom of the prism and the skin tissue to provide indirect contact.

26. An optical element, the optical element being shaped to receive one or more light energy beams and cause the one or more light energy beams to be bent by the optical element and be converged and focused to a single focal point at or below a bottom surface of the optical element; and,

wherein the one or more light energy beams each diverge after passing through the single focal point to create a plurality of angled light energy beams emanating from the single focal point.

27. The optical element of claim 26, wherein the optical element is a prism with a flat bottom and three or more angled sides having a common apex, and wherein the flat bottom is adapted to be placed in contact with a skin tissue surface.