# US 2019/0167348 A1 · Light based skin treatment device

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- Number: US 2019/0167348 A1
- Document ID: US20190167348A1
- Status: Published application
- Kind: A1
- Application number: 16/324,331
- Filed: 2017-08-08
- Published: 2019-06-06
- Earliest claimed: 2016-08-09
- Assignees: Koninklijke Philips N.V.
- Applicants: Koninklijke Philips N.V.
- Inventors: BABU VARGHESE; RIEKG VERHAGEN
- Web page: https://patentgrep.com/patent/US20190167348A1

## CPC

- A61B 18/203: {applying laser energy to the outside of the body}
- A61B 2018/00107: {Coatings on the energy applicator}
- A61B 2018/00452: {Skin}
- A61B 2018/0047: {Upper parts of the skin, e.g. skin peeling or treatment of wrinkles}
- A61B 2018/00476: {Hair follicles}
- A61B 2018/202: {Laser enclosed in a hand-piece}
- A61B 2018/20355: {Special scanning path or conditions, e.g. spiral, raster or providing spot overlap}
- A61B 2018/20359: {by movable mirrors, e.g. galvanometric}
- A61B 2018/20361: {with redirecting based on sensed condition, e.g. tissue analysis or tissue movement}
- A61B 2018/20553: {with special lens or reflector arrangement}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A light based skin treatment device comprises a laser light source for providing a pulsed incident light beam for treating skin by laser induced optical breakdown of hair or skin tissue. In one arrangement, a focusing system has a pre-focusing lens for increasing the convergence of the an incident light beam and a skin contact lens having convex light input and light exit surfaces. The focal spot position is controlled by adjusting a spacing between the pre-focusing lens and the skin contact lens. In another arrangement, there is an adjustable lens system before an adjustable focusing system for providing compensation for aberration in the focusing system.

## Claims

### Claim 1

A light based skin treatment device, comprising:
a light source for providing a pulsed light beam for generating a laser induced optical breakdown of hair or skin tissue;
a focusing system for focusing the pulsed light beam into a focal spot in the hair or skin tissue, wherein the focusing system comprises:
a pre-focusing lens for generating a convergent pulsed light beam from the pulsed light beam; and
a focusing lens having:
a convex light input surface for receiving the convergent pulsed light beam;
a light exit surface for contacting the skin or hair;
a refractive index of 1.4 or higher; and
a focus controller for controlling a distance of the focal spot to the light exit surface by adjusting a spacing between the pre-focusing lens and the focusing lens.

### Claim 2 (depends on 1)

The light based skin treatment device according to claim 1, wherein a curvature of the convex light input surface is within an area of incidence of the convergent pulsed light beam on the convex light input surface, and wherein light rays of the converging pulsed light beam enter the focusing lens substantially perpendicularly to the convex light input surface for at least one particular spacing.

### Claim 3 (depends on 1)

The light based skin treatment device according to claim 1, wherein the light exit surface is convex.

### Claim 4 (depends on 1)

The light based skin treatment device according to claim 1, wherein the pulsed light beam to the pre-focusing lens is convergent.

### Claim 5 (depends on 1)

The light based skin treatment device according to claim 1, wherein the pre-focusing lens comprises an aspheric lens.

### Claim 6 (depends on 1)

The light based skin treatment device according to claim 1, wherein the pre-focusing lens comprises:
a further convex light input surface; and
a planar further light output surface or a convex further light output surface with an average radius of curvature greater than the average radius of curvature of the light input surface.

### Claim 7 (depends on 1)

The light based skin treatment device according to claim 1, wherein the focusing lens has an index of refraction at a wavelength of the pulsed light beam in the range between 1.4 and 1.6.

### Claim 8 (depends on 1)

The light based skin treatment device according to claim 1, wherein the focusing lens is formed of Borosilicate Crown (BK) glass or fused silica.

### Claim 9 (depends on 1)

The light based skin treatment device according to claim 1, wherein the outer surface of the focusing lens comprises an anti-reflection coating at the light exit surface for reducing reflection of the pulsed light beam.

### Claim 10 (depends on 1)

The light based skin treatment device according to claim 1, wherein the focus controller comprises a holder including:
a number of pre-focusing lenses such that each lens can be inserted in a light path one at a time, wherein each lens defines a predetermined spacing when inserted in the light path such that one spacing is different from another,
a number of focusing lenses such that each lens can be inserted in a light path one at a time, wherein each lens defines a predetermined spacing when inserted in the light path such that one spacing is different from another, or
a number of pairs of the pre-focusing lens and the focusing lens such that each pair can be inserted in a light path one at a time, wherein each pair defines a predetermined spacing when inserted in the light path such that one spacing is different from another.

### Claim 11 (depends on 1)

The light based skin treatment device according to claim 1, further comprising an adjustable lens system arranged in a path of the pulsed light beam before the focusing system for providing compensation for aberration in the focusing system.

### Claim 12 (depends on 11)

The light based skin treatment device according to claim 11, wherein the adjustable lens system comprises an electrically tunable lens.

### Claim 13 (depends on 12)

The light based skin treatment device according to claim 12, wherein the adjustable lens system further comprises a negative lens at an output of the electrically tunable lens.

### Claim 14 (depends on 11)

The light based skin treatment device according to claim 11, further comprising a scanning system for scanning the focal spot, wherein the adjustable lens system is provided at an input to the scanning system.

### Claim 15

A method for providing a light based skin treatment, comprising:
providing a pulsed light beam for generating laser induced optical breakdown of hair or skin tissue;
focusing the pulsed light beam into a focal spot in the hair or skin tissue using a focusing system comprising a pre-focusing lens and a focusing lens;
providing the pulsed light beam to the pre-focusing lens to generate a convergent pulsed light beam
using the focusing lens having a refractive index of 1.4 or higher and a convex light input surface for receiving the convergent pulsed light beam;
using the focusing lens having a light exit surface for contacting the hair or skin tissue; and
controlling a distance of the focal spot to the light exit surface by adjusting a spacing between the pre-focusing lens and the focusing lens.

### Claim 16 (depends on 15)

The method according to claim 15, further comprising providing compensation for aberration using an adjustable lens system in a path of the pulsed light beam before the focusing system.

### Claim 17

(canceled)

### Claim 18

(canceled)