WO2010004500A1

WO2010004500A1 - Versatile cosmetic appliance

Info

Publication number: WO2010004500A1
Application number: PCT/IB2009/052928
Authority: WO
Inventors: Giovanna Wagenaar Cacciola; Peter Deixler; Rene T. Wegh
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2008-07-10
Filing date: 2009-07-06
Publication date: 2010-01-14

Abstract

Proposed is a cosmetic appliance (100). It has a housing (1) and comprises a light source module (10) arranged to emit light in a predefined first wavelength range through the use of one or more light sources (11), f.i. LEDs. An optical module (20) is arranged to deliver light emitted by the light source module (10) to a user's body part to achieve a first cosmetic effect. As an example, the cosmetic effect targeted may be tanning (using light in the range 400-440 nm), acne reduction (400-440 nm), or psoriasis reduction (300-360 nm). The optical module comprises an adjustable color converting device (30) arranged to convert light of the first wavelength range to light in a predefined second wavelength range to achieve a second cosmetic effect, for instance, skin rejuvenation (580 - 660 nm).

Description

Versatile cosmetic appliance

FIELD OF THE INVENTION

The invention relates to a cosmetic appliance comprising a light source module arranged to emit light in a predefined first wavelength range, and an optical module arranged to deliver light emitted by the light source module to a user's body part to achieve a first cosmetic effect. Such appliances are used//, to achieve acne reduction, acne scare reduction, wrinkle reduction through collagen and fibroblast activation, and tanning of the skin.

BACKGROUND OF THE INVENTION An embodiment of a cosmetic appliance of the kind set forth is known from

US2007/0139930. That document discloses a cosmetic appliance comprising LEDs for illuminating body parts (such as face, arms, back, thighs, buttocks, or even full body) of a user to achieve a cosmetic effect. The cosmetic or medic effect targeted using an appropriate light therapy protocol could be acne, cellulite, or psoriasis reduction. The specific protocol (i.e. the exposure time and exposure repetition frequency) depends on the cosmetic effect targeted and the irradiation level on the skin realised with the appliance. Furthermore, the different cosmetics effects correlate to specific wavelength ranges: acne (400-440 nm), psoriasis (300-360 nm), wrinkle treatment / skin rejuvenation (580-660 nm), cellulite (660- 1450nm). US2007/0139930 describes different embodiments of the cosmetic appliance to comprise a specific set of LEDs optimised for a specific treatment, in other words: the LEDs are arranged to emit light in a predetermined first wavelength range to achieve a first cosmetic effect. Clearly, combining different sets of LEDs to emit in a first and a second wavelength range for achieving a first and second cosmetic effect can easily be achieved,//. by inter-mixing a first and second array of the respective LEDs. This however has as a drawback that it reduces the (average) irradiation/illumination level achievable by the appliance for a specific treatment. This in turn has an effect on the protocol, i.e. lengthening the exposure time. Possibly, the irradiation/illumination level is reduced to such an extent that it excludes achieving the targeted cosmetic effect all together. Moreover, combining different LEDs in this way makes the appliance more bulky. Furthermore it has a negative economical effect as working with more components usually increases bill-of-material, logistics, and assembly costs.

SUMMARY OF THE INVENTION

The invention has as an objective providing a cosmetic appliance of the kind set forth, in which at least one of the drawbacks is partially alleviated. This object is achieved with the cosmetic appliance according to the invention as defined in the pre-amble of claim 1 and characterized in that the optical module comprises an adjustable color converting device arranged to convert light of the first wavelength range to light in a predefined second wavelength range to achieve a second cosmetic effect. Advantageously this allows assembling the cosmetic appliance with a single set of light sources emitting in the first wavelength range and adjust the color converting device to obtain light in the second wavelength range when needed. Consequently, adjusting the color converting device to refrain from any conversion maintains the irradiation/illumination level in the first wavelength range for the first cosmetic effect. Moreover, adjusting the color converting device to convert quasi 100% of the light in the first wavelength range to light in the second wavelength range optimizes the irradiation/illumination level for the second cosmetic effect. In an embodiment, the color converting device comprises a transparent or translucent element comprising a color converting medium. In an embodiment, the color converting medium is dispersed in or deposited on the transparent or translucent element. In yet another embodiment, the color converting medium is homogeneously dispersed in or deposited on the transparent or translucent element. In still another embodiment, the color converting medium is dispersed in or deposited on the transparent or translucent element forming a pattern. Beneficially these embodiments allow the cosmetic appliance to be manufactured in a wide variety of models and optimised for specific cosmetic effects to be achieved.

In an embodiment, the color converting medium comprises a phosphor. In an embodiment, the phosphor is chosen from the group comprising (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN₃:Eu, (Ba₅Sr₅Ca)₂Si₅N₈ :Eu, and Mg₄GeO₅FiMn. Advantageously, the phosphors mentioned have an absorption band in the 400 - 440 nm range and a (tuneable) emission band in the 580 - 660 nm range, allowing the cosmetic appliance to be optimized for several widely desired cosmetic effects. Hence, in an embodiment the light source module comprises at least one LED, wherein the first wavelength range is 400 - 440 nm, and wherein the first cosmetic effect is UV-free tanning or acne reduction. In another embodiment, the second wavelength range is 580 - 660 nm, and wherein the second cosmetic effect is skin rejuvenation.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details, features and advantages of the invention are disclosed in the following description of exemplary and preferred embodiments in connection with the drawings.

Fig. 1 schematically shows an embodiment of the invention in front-view and in side-view.

Fig. 2 schematically shows a second embodiment of the invention.

Fig. 3 schematically shows a third embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Figure 1 schematically shows in front-view and in side-view a cosmetic appliance 100. It has a housing 1 and comprises a light source module 10 arranged to emit light in a predefined first wavelength range through the use of one or more light sources 11, f.i. LEDs. An optical module 20 is arranged to deliver light emitted by the light source module 10 to a user's body part to achieve a first cosmetic effect. As an example, the cosmetic or medic effect targeted may be tanning (using light in the range 400-440 nm), acne reduction (400-440 nm), or psoriasis reduction (300-360 nm). The optical module 20 comprises//, a plane sheet of a transparent or translucent material, such as glass, PC, or PMMA. Alternatively, the optical module 20 may comprise a (multiplicity of) Fresnel lens(es) 21, a micro-lens array, or any other optical structure arranged to achieve a specific illumination pattern. Moreover, the optical module 20 comprises an adjustable color converting device 30 arranged to convert light of the first wavelength range to light in a predefined second wavelength range to achieve a second cosmetic effect. For clarity reasons the color converting device 30 is shown only in the side-view of the cosmetic appliance 100.

In an embodiment, the color converting device 30 comprises a transparent or translucent element 40 comprising a color converting medium 50, as shown in Fig. 2. The element 40 may for instance be a plane or free-form sheet of glass, PC, or PMMA. In an embodiment, the optical module 20 is arranged to have slots so as to slidingly receive the color converting device 30.

In another embodiment, the color converting device 30 may be arranged as a hinged element. Advantageously, this allows a user to manually adjust the cosmetic appliance 100 in order to achieve the first or second cosmetic effect.

The color converting medium 50 may be homogenously dispersed inside or deposited on the transparent or translucent element 40. Alternatively, the color converting medium 50 may form a pattern (see Fig. 2). Preferably, the pattern of the color converting medium corresponds with the pattern of the light sources 11. Advantageously, the color converting device 30 then only needs to be adjusted (f.i. through sliding - either manually or electrically using as an example piezoelectric elements) over a small distance. In a first position, the color converting device 30 is arranged such that the pattern of the color converting medium 50 and the array of light sources 11 do not overlap (f.i. through shifting the pattern and the array relative to each other over half a unit cell). As a result, light emitted in the first wavelength range by the light sources in an axial direction away from the cosmetic appliance 100 will not be absorbed by the color converting medium 50, but instead transmitted through the optical module 20 enabling achieving the first cosmetic effect. In a second position, the color converting device 30 is arranged such that the pattern of the color converting medium 50 overlaps with the array of light sources 11. As a result, light emitted by the light sources in an axial direction away from the cosmetic appliance 100 will be absorbed and converted to the second wavelength range enabling achieving the second cosmetic effect.

Fig. 3 schematically shows another embodiment of the color converting device 30 according to the invention. Again, the color converting medium 50 forms a patterned in or on the transparent or translucent element 40. Here, two different color converting media 51,52 have been applied allowing in dependence of the selection a second and a third cosmetic effect. The converting media 51,52 form two interwoven arrays, allowing the color converting device 30 to be adjusted to a first position in which the light from the light sources 11 is not converted (first cosmetic effect), to a second position in which the light from the light sources 11 is converted by color converting medium 51 (second cosmetic effect), and to a third position in which the light from the light sources 11 is converted by color converting medium 52 (third cosmetic effect). Alternatively, the second and third cosmetic effect may be achieved simultaneously in a position of the color converting device 30 in which light from the light sources 11 is converted by both color converting media 51,52. In an embodiment the color converting medium 50 comprises a phosphor. Beneficially the phosphor is chosen from the group comprising (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN₃:Eu, (Ba₅Sr₅Ca)₂Si₅N₈ :Eu, and Mg₄GeO₅FMn. These phosphors have an absorption band (above 60%) in the wavelength range: (Ba,Sr,Ca)S:Eu 200 - 300 nm & 425 - 575 nm

(Ba,Sr,Ca)AlSiN₃:Eu 250 - 550 nm

Ba,Sr,Ca)2Si₅N₈:Eu 250 - 525 nm

Mg₄GeO₅FiMn 200 - 450 nm

Moreover, their emission band falls in the wavelength range 580 nm - 660 nm. In fact, by appropriate choice and ratio of the (Ba,Sr,Ca) metal ions, the emission spectrum can be tuned to have its peak at a predefined wavelength within this range. The notation (A,B,C) signifies (A_x,B_y,C_z), where O≤x≤l, O≤y≤l, and O≤z≤l, and x+y+z=l. Typically x, y, and z are all non-zero.

Thus, in an embodiment the cosmetic appliance 100 is provided with LEDs emitting in the 400 - 440 nm range, enabling//. UV-free tanning and acne treatment as the first cosmetic effect. Moreover, providing the color converting device 30 with (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN₃:Eu, or (Ba₅Sr₅Ca)₂Si₅NsIEu phosphors allows a user to be illuminated with light optimised for the anti- wrinkle treatment. Alternatively, Mg₄GeO₅FiMn can be used in the color converting medium 50, as it exhibits an absorption maximum at 420 nm and an emission maximum at 660 nm. In contrast to the Eu doped phosphors, its emission band can hardly be tuned.

In yet another embodiment, the adjustable color converting device 30 comprises an electro -wetting cell. Electro -wetting is the phenomenon whereby an electrical field modifies the wetting behaviour of an electrically susceptible fluid in contact with a partially wetted (i.e. a contact angle larger than 0° in absence of a voltage) insulated electrode and in direct electrical contact with - or capacitively coupled to - a second electrode. If an electrical field is applied by supplying a voltage between the electrodes, a surface energy gradient is created which can be used to manipulate an electrolyte (a polar fluid) to move towards the insulated electrode or to replace an apolar fluid. Advantageously, this allows adjusting the color conversion electronically by actuating the surface/shape of a droplet comprising an electrolyte through the application of a voltage. The electrolyte in the electro- wetting cell (or the apolar fluid for that matter) may comprise the color converting medium 50, thus allowing to adjustably control the color conversion of light of the first wavelength range into light of the second wavelength range. In an embodiment the color converting medium 50 comprises a fluorescent dye (or combinations of dyes). This dye can be chosen from//, the Lumogen®, Rhodamine or Coumarin families.

Although the invention has been elucidated with reference to the embodiments described above, it will be evident that alternative embodiments may be used to achieve the same objective. The scope of the invention is therefore not limited to the embodiments described above. Accordingly, the spirit and scope of the invention is to be limited only by the claims and their equivalents.

Claims

CLAIMS:

1. A cosmetic appliance (100) comprising: a light source module (10) arranged to emit light in a predefined first wavelength range, and an optical module (20) arranged to deliver light emitted by the light source module (10) to a user's body part to achieve a first cosmetic effect, characterised in that the optical module comprises an adjustable color converting device (30) arranged to convert light of the first wavelength range to light in a predefined second wavelength range to achieve a second cosmetic effect.

2. A cosmetic appliance (100) according to claim 1, wherein the color converting device (30) comprises a transparent or translucent element (40) comprising a color converting medium (50).

3. A cosmetic appliance (100) according to claim 2, wherein the color converting medium (50) is dispersed in or deposited on the transparent or translucent element (40).

4. A cosmetic appliance (100) according to claim 3, wherein the color converting medium (50) is homogeneously dispersed in or deposited on the transparent or translucent element (40).

5. A cosmetic appliance (100) according to claim 3, wherein the color converting medium (50) is dispersed in or deposited on the transparent or translucent element (40) forming a pattern.

6. A cosmetic appliance (100) according to claim 2, wherein the color converting medium (50) comprises a phosphor.

7. A cosmetic appliance (100) according to claim 6, wherein the phosphor is chosen from the group comprising (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu, (Ba₅Sr₅Ca)₂Si₅N₈ :Eu, and Mg₄GeO₅FMn.

8. A cosmetic appliance (100) according to claim 1, wherein the light source module (10) comprises at least one LED, wherein the first wavelength range is 400 - 440 nm, and wherein the first cosmetic effect is tanning or acne reduction.

9. A cosmetic appliance (100) according to claim 1, wherein the second wavelength range is 580 - 660 nm, and wherein the second cosmetic effect is skin rejuvenation.