Hair shortening device

Patent metadata

Field	Value
Publication number	US-9622817-B2
Application number	US-8920106-A
Country	US
Kind code	B2
Filing date	Sep 27, 2006
Priority date	Oct 3, 2005
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

The invention relates to a hair-shortening device. The device is based on the principle of laser-induced optical breakdown, wherein a laser pulse causes mechanical effects in tissue, which are used to cut the hair ( 20 ). The invention uses the insight that, when two or more such laser pulses are provided simultaneously, the mechanical effects can co-operate. This in turn allows cutting of the hair ( 20 ) with less total energy, down to about half the energy required for cases with pulses that are supplied sequentially. In one embodiment, the device comprises a laser source ( 2 ), a grating ( 6 ), and a beam manipulator ( 8 ), that aim a plurality of simultaneous focal spots ( 10 ) into a hair ( 20 ).

First claim

The invention claimed is:

1. A device for shortening hairs, the device comprising:
a laser source configured to generate a plurality of laser pulses at peak power density for a predetermined pulse time;
an optical system configured to focus the plurality of laser pulses into each of a plurality of spatially separated focal spots within a single hair such that at least three of the plurality of focused laser pulses overlap in time and co-operate to reduce a total power required and the peak power density of each of the at least three laser pulses in the respective focal spots with the peak power density at least equal to a first characteristic threshold value at which a laser induced optical breakdown phenomenon occurs in the hair tissue wherein fractures in the hair result between the respective focal spots and to below a second characteristic threshold value at which a laser induced optical breakdown phenomenon occurs in the skin tissue; and
an optical manipulator configured to position the respective at least three focal spots into respective target positions substantially in a 2D plane within the single hair, wherein the optical system is further configured such that a focal spot positioned substantially within the medulla of the single hair has an increased power over each of others of the plurality of spatially separated focal spots not positioned substantially within the medulla of the single hair.

2. The device according to claim 1 , wherein the plurality of laser pulses overlap in time.

3. The device according to claim 1 , wherein the optical system comprises a beam multiplier element configured to multiply an incident beam of laser pulses into a plurality of simultaneously outgoing beams of laser pulses.

4. The device according to claim 3 , wherein the optical system comprises a grating.

5. The device according to claim 3 , wherein the beam multiplier element is configured to move, rotate and pivot.

6. The device according to claim 1 , wherein the optical manipulator is configured to provide a number of the plurality of spatially separated focal spots that are between 7 and 20.

7. The device according to claim 1 , wherein the optical manipulator is configured to provide a distance between the target positions substantially in the 2D plane of between 10 and 25 μm between contiguous respective focal spots.

8. The device according to claim 7 , wherein the optical manipulator is configured to provide the distance to be at most equal to a diameter of a hair to be shortened divided by a number of the plurality of spatially separated focal spots within the single hair.

9. The device according to claim 7 , wherein a total energy applied by the plurality of laser pulses to the sin e hair is 1.5 to 3 mJ.

10. The device according to claim 1 , wherein the optical manipulator is configured to provide the plurality of spatially separated focal spots arranged in a 3D pattern extending through the single hair to be shortened.

11. The device according to claim 1 , wherein the optical manipulator is configured to provide the plurality of spatially separated focal spots arranged in the 2D plane that extends through the single hair to be shortened, with the 2D plane substantially perpendicularly to the shaft of the single hair.

12. The device according to claim 11 , wherein the optical manipulator is configured to provide the plurality of spatially separated focal spots arranged substantially in the 2D plane in an equilateral triangular pattern of the at least three focal spots.

13. The device according to claim 1 , wherein the optical manipulator is configured to provide the plurality of spatially separated focal spots arranged substantially in the 2D plane on a straight line extending through the single hair to be shortened, with the plane substantially perpendicularly to the shaft of the single hair.

14. The device according to claim 1 , wherein the laser source is configured to generate the plurality of laser pulses with said peak power density between 70% and 85% of the second characteristic threshold value.

15. The device according to claim 1 , wherein the laser source is configured to generate the plurality of laser pulses with said peak power density between 5.5·10 11 W/cm 2 and 7·10 11 W/cm 2 and a pulse duration of 8-10 ns.

16. The device according to claim 1 , wherein the laser source is configured to generate the plurality of laser pulses with a temporal profile of power density of the plurality of laser pulses such that the peak power density and the first characteristic threshold value is reached after start of the pulse in less than 25% of a duration of the start of the pulse.

17. The device according to claim 1 , wherein the laser source is configured to generate the plurality of laser pulses with a temporal profile of power density of the plurality of laser pulses such that more than 70%, of the energy in the pulse is delivered after reaching the peak power density with a total energy applied by the plurality of laser pulses to the single hair of 1.5 to 3 mJ.

18. A device for shortening hairs, the device comprising:
a laser source configured to generate a plurality of laser pulses at peak power density for a predetermined pulse time;
an optical system configured to focus the plurality of laser pulses into each of a plurality of spatially separated adjacent focal spots within a single hair such that at least three of the plurality of focused laser pulses overlap in time and co-operate to reduce a power required and the peak power density of each of the at least three laser pulses in the respective focal spots with the peak power density at least equal to a first characteristic threshold value at which a laser induced optical breakdown phenomenon occurs in the hair tissue wherein fractures in the hair result between the respective focal spots and to below a second characteristic threshold value at which a laser induced optical breakdown phenomenon occurs in the skin tissue; and
an optical manipulator configured to manipulate positions of the respective at least three focal spots into respective target positions substantially in a 2D plane within the single hair, and
wherein the optical system and laser source are further configured such that a focal spot positioned substantially within the medulla of the single hair has an increased power over each of others of the plurality of spatially separated focal spots not positioned substantially within the medulla of the single hair with a distance between the manipulated positions of the adjacent focal spots of the plurality of spatially separated focal spots is at most equal to a distance required for the fractures in the single hair between the respective focal spots to join fractures of adjacent focal spots.

19. The device according to claim 18 , wherein the laser source is configured to generate the plurality of laser pulses with a temporal profile of power density of the plurality of laser pulses such that the peak power density and the first characteristic threshold value is reached after a start of the pulse in less than 25% of a duration of the start of the pulse.

20. The device according to claim 19 , wherein the laser source is configured to generate the plurality of laser pulses with a temporal profile of power density of the plurality of laser pulses such that more than 70%, of the energy in the pulse is delivered after reaching the peak power density with a total energy applied by the plurality of laser pulses to the single hair of 1.5 to 3 mJ.

Assignees

• Van Hal Robbert Adrianus Maria
• Verhagen Rieko
• Koninklijke Philips Nv

Inventors

• Van Hal Robbert Adrianus Maria
• Verhagen Rieko

Classifications

• A61B2018/00452

  Skin · CPC title

• A61B18/203 Primary

  applying laser energy to the outside of the body · CPC title

• A61B2018/00476

  Hair follicles · CPC title