DEVICE FOR THE SAFE, PAINLESS AND PERMANENT REMOVAL OF UNWANTED HAIRGROWTH

Abstract: The object of the invention is a device for the safe and painless permanent removal of unwanted body hair by means of light. Semiconductor (22) and/or laser diodes (23) mounted on a printed circuit board serve as the light-source. The diodes (22, 23) can be individually selected - switched ON or OFF. They emit light at different wavelengths. An optic (16, 16') mounted in the applicator (14) focuses the light on to the skin to be treated. A photo-sensor (24) mounted on the printed circuit board (21) registers the reflection of light from the skin's surface. With this biofeedback signal, the radiation intensity and wavelength of the light-source (20) can be semi- or fully automatically adjusted. The invention is for dermatological use.

Description: Device for the safe, painless and permanent removal of unwanted hairgrowth. Background of the invention: The invention concerns devices for the safe, painless and permanent removal of unwanted hairgrowth in accordance with the specification in claim 1. State of the Art. The removal of unwanted hairgrowth by means of light is already known. U.S. Patent No. 5.226.907 proposes the use of a CO2 laser with a wavelength of ca. 10.000 nm, or a pulsed dye laser with wavelengths of 531 , 584, 587 or 632 nm. The applicator covers a treatment area of ca. 1 cm2, and the radiation intensity is from 5 to 10 J/cm2. Prior to treatment, however, the skin must be treated with a photosensitizer, such as a suspension of carbon in oil, which must penetrate through to the hair-roots via the pores. WO 95/15725 proposes, for the same purpose, a ruby laser with a wavelength of 694 nm, a neodyme-YAG laser with a wavelength of 1064 nm, or the use of any other laser with a wavelength of between 600 and 1500 nm. The pulse-length should be between 1 μsec. and 1 millisec. U.S. Patent No. 5.059.192 describes the use of a ruby laser which emits a light-pulse of 30-40 nsec, treating an area of ca. 3 mm. with an intensity of 0,4 to 10 J/cm2. The irradiation time should be under 2 msec. U.S. Patent No. 4.388.924 proposes the use of an argon laser with a wavelength of between 480 and 520 nm. The laser-beam should have a strength of 0,5 to 2,5 W and the treatment time be between 10 and 400 msec. The light is transferred from the laser to the applicator by means of photo-optic fibres. U.S. Patent No. 4.608.978 describes a device for the removal of unwanted body-hair with the use of a flashtamp. The flashlamp is located in the main unit of the apparatus, the light being conveyed to the applicator by means of photo-optics. No reference is made to the wavelength of the light, but it is known that the light from a flashlamp lies in the wavelength area of 180 to 2000 nm. U.S. Patent No. 5.066.293 proposes the use of an adjustable dye-laser for derma- tological applications. The skin should be pretreated with a light-absorptive suspension, i.e. a photosensitizer. Finally, GB 21 23 287 describes a device for the removal of unwanted body-hair which entails that each individual hair must be threaded into an opening in the hand- applicator. Albeit that this method is probably gentler with the surrounding dermal tissue, the threading of each individual hair is so time-consuming as to render the method impractical. In practice, areas of skin are always treated, in facial areas with a beam of 10 mm diameter and in body areas with a beam of 30 mm diameter. These state of the art devices all entail a certain risk for the patient, as they are very powerful. A CO2 laser, for instance, develops a beam with a strength of some hundred Watts. For this reason, the above mentioned papers all propose pulsed beams interrupted by pauses of corresponding length. Nevertheless, through technical or human error patients can still suffer severe skin lesions with consequent scarring. Moreover, surgical laser equipment is very expensive and can only be operated by specially trained doctors. These factors make hair-removal with laser very expensive, and thus reduce the availability of this method. Summary of the invention: The invention addresses the task of improving the characteristics of devices for the removal of unwanted body hair through the following aims; to ensure patient safety from tissue damage in the event of technical or human operational error, to be cheaper, and to enable a painless treatment without side-effects. The task is solved through two devices. The first device, which is the subject of patent claim 1 , uses as its light-source at least one semiconductor diode and / or at least one laser diode, whereby the light-source is adjustable according to the colour of the hair and the skin type. The second device, the subject of patent claim 8, uses a flashlamp as its light-source, with colour filters which can be changed according to the hair colour and skin type. The rationale behind these inventions is that with a lower radiation intensity the treatment will be much more free from problems, and the devices can be manufactured to much lower cost. The constant and safe functioning is guaranteed by the fact that the strength of the light can be adjusted according to the colour, or rather the absorptive quality of the hair and skin type being treated. Thereby LED-diodes or also laser diodes of class A or B can be used as light-sources. One further development of the invention is that the light-source contains at least one adjustable laserdiode. Laserdiodes whose wavelength can be adjusted by means of a piezo-element are customary. Another further development of the invention is that the light-source contains at least one semiconductor diode which can produce light of different wavelengths. It is known that certain LED-diodes, with suitable input, can emit light at wavelengths of 600, 900 and 1200 nm. The light-sources should preferably contain several semiconductor and / or laser diodes which can emit light at different wavelengths. Therefore the radiation from the diodes should preferably be individually selectable - switched ON or OFF, thus rendering it possible to adjust both the radiation power and wavelength of the inventions. A further development of the device is the inclusion of a photosensor in the applicator which senses the light reflected from the skin. Thus it is possible to regulate the radiation intensity and the absorption of light into the skin. The photosensor enables a fully automatic tuning of the light intensity and most particularly of the wavelength. Finally, it is possible to install a further sensor which monitors the contact of the applicator with the patient's skin and immediately switches off the beam if the contact is broken. Brief description of the invention: The following points refer to the explanatory diagram: Fig.1 control and power unit, Fig.2 applicator for skin area, Fig.3 side- and overhead view of light-source with optics, Fig.4 a further device for the removal of unwanted body hair, Fig.5 a second applicator for use with the device in fig.4. Detailed description of the invention: Fig.1 shows a control and power unit 10 in its casing, with buttons 11 for adjustment of treatment time, frequency, intensity, radiation intensity in J/cm2 etc. The installed values can be read on a display 12. Access is subject to a personal passcode. The control and power unit 10 can be run either from 110/230 V AC or from low-voltage DC. Four different applicators can be connected to the control and power unit 10. Fig.2 shows a first applicator which is connected to the control and power unit 10 by means of cable 13. The applicator- housing has a start-button 19 and a standby indicator 18. A light-source and an optic are installed in the front casing 14. Part 14 is interchangeable. As fig 2. shows, the tip of the applicator is placed against the skin 2 with the hair 1 , and the start-button 19 is pressed. The light beam penetrates the skin to the hair roots and destroys them. Correct adjustment of the light's wavelength will give optimal absorption into the hair 1 and hair root, whilst absorption into the surrounding skin 2 should be minimal. The risk of burns with resultant blistering and scarring will with all certainty be avoided. A contact-sensor 9 registers the applicator's contact with the skin 2. Fig 3. shows a light-source 20 and the pertaining optics 16,16'. On a printed circuit- board 21 , twelve LED-diodes 22 and four laser diodes 23 are installed. The radiation from the diodes 22 and 23 are individually selectable - switched ON or OFF. They emit light of different wavelengths. This enables the adaptation of radiation intensity and wavelength to the colour of the hair 1 and the type of skin 2. The light emitted by the diodes 22, 23 is first concentrated in the lenses 16, 16', before it reaches the skin. In the centre of the printed circuit-board 21 a photosensor 24 is located. This receives the light which is reflected back from the skin. This feedback signal is used in the control and power unit to regulate the radiation intensity and the wavelength of the light-source semi- and fully-automatically. Fig.4 shows a second device for the removal of unwanted body hair. This consists of a control and power unit 10', with a flashlamp 20' as light-source. In front of the flashlamp 20' are the colour filters 25, by means of which the light can be filtered to an optimal wavelength in the range 180 to 2000 nm for the respective patient. The filtered light is conducted by means of optic fibres 17 to an applicator 15 where it is focused by optic 16. The treatment procedure is started with start-button 19. The tip of the applicator 15 has a diameter of eg. 10 mm and is thus suitable for the depilation of facial skin. Fig 5 shows an applicator 15' with a tip of ca. 30 mm diameter, which is suitable for the depilation of body areas. The invention is intended for medical and / or cosmetic skin treatment.

Claims: Claims: 1. A device for safe and painless permanent removal of unwanted body hair, comprising: - a light-source (20, 20') with - suitable strength, - suitable wavelength, - a light conductor (25), - an applicator ( 14, 15, 15'), - an optic (16, 16'), - and a control and power unit (10, 10'), characterized by the following: - the light-source (20) consists of at least one semiconductor diode (22) and / or at least one laser diode (23), - the wavelength of the light source (20) is adjustable to correspond with the hair colour and skin type. 2. A device as described in claim 1 , wherein: - the light-source (20) contains at least one adjustable laser diode (23). 3. A device as described in claim 1 , wherein: - the light-source (20) contains at least one semiconductor diode (22), which produces light of different wavelengths. 4. A device as described in claim 1 , wherein: - the light-source (20) contains several semiconductor and / or laser diodes (22, 23), which emit light of different wavelengths. 5. A device as described in claim 4, wherein: - the diodes (22, 23) are individually selected - switched ON or OFF. 6. A device as described in claim 1 , wherein: - the applicator contains a photosensor (24) for the light reflected from the skin (2) surface. 7. A device as described in claims 4, 5 or 6, wherein: - the diodes (22, 23) and / or the photosensor (24) are located on a printed circuit board (21). 8. A device for the safe and painless permanent removal of unwanted body hair, comprising: - a light-source (20, 20') with - suitable strength - and suitable wavelength, - a light conductor (25), - an applicator (14, 15, 15'), - an optic (16, 16') - and a control and power unit (10, 10') wherein : - the light-source consists of a flashlamp (20'), - the flashlamp (20') is placed behind changeable colour filters (25) corresponding to the hair colour and skin type. 9. A device as described in claim 8, wherein: - the applicator (15, 15') contains a photosensor (24) for the light reflected from the skin (2). 10. A device as described in claims 1 or 8, wherein: - the applicator (14, 15, 15') contains a contact-sensor (9).

Inventors: LARSEN ERIC, LARSEN, ERIC
Applicants: HOEGSETH SOLFRID, LARSEN ERIC, HOEGSETH, SOLFRID, LARSEN, ERIC
Application year: 1997
Main classification: A61B17
IPC codes: A61B17, A61B18, A61B19, A61N5