Handheld intense pulsed light device with light guide

Abstract

The invention relates to a handheld intense pulsed light apparatus comprising a body configured to be held in the hand, said body having an opening receiving a treatment interface (8) configured to be placed against a skin, the body housing a lamp (14) adapted to emit a light pulse through the treatment interface in an emission direction, the treatment interface comprising a light guide (10) projecting from the body of the handheld apparatus, the light guide (10) forming a polyhedron having end faces (10a) opposite in the emission direction and lateral faces (10b) connecting said end faces, the light guide (10) having a thickness, between the end faces (10a) in the emission direction, greater than 6 mm, and the lateral faces (10b) having a roughness with an arithmetic mean deviation Ra less than or equal to 3.2. Figure for abstract: FIG. 2

Description

Title of the invention: Handheld device for intense pulsed light with light guide Technical field

[0001] The present invention belongs to the field of human body photo-stimulation systems, and more specifically relates to a hand-held device with intense pulsed light with a light guide, in particular for ophthalmic applications, state of the art

[0002] The principle of intense pulsed light (IPL) is based on the emission of light towards the skin. An intense pulsed light system comprises a console and a hand-held device. The operator sets the parameters of the light pulse (duration, intensity, etc.) on the console, then places the hand-held device in contact with the patient's area to be treated, and finally triggers the light shot. The light interacts with components of the skin or subcutaneous components, depending on the wavelengths. The impact time of the light pulse can vary from 1 ms to 100 ms.

[0003] The handheld intense pulsed light device thus comprises a body configured to be held in the hand, said body having an opening receiving a treatment interface configured to be placed against skin. It is possible to apply a gel to ensure good contact and good light transmission.

[0004] However, current hand-held intense pulsed light devices are not entirely satisfactory. They suffer from a lack of precision, as the current configuration does not allow the operator to correctly visualize the treated area. In addition, the uniformity of light emission over the treatment area is generally poor.

[0005] Such limitations are not problematic when the hand-held pulsed intense light device is used for applications that do not require high precision, such as for example skin aesthetics, mainly permanent or semi-permanent hair removal (photo-epilation), semi-permanent hair removal, or the treatment of signs of aging such as pigment spots (photo-depigmentation). However, applications such as treatments may require more precision in the treatment area, and current hand-held devices are not suitable for this. This is for example the case for ophthalmic applications such as the light stimulation of the lacrimal ducts, where the treated area must be precisely located under the eye. If it is too far from the eye, the stimulation will not produce the expected effect, while conversely being too close to the eye can be dangerous. It becomes It is therefore all the more important that the entire treated area receives an adequate amount of light, since there is no question of moving the hand-held device to smooth out unevenness. PRESENTATION OF THE INVENTION

[0006] The aim of the invention is to propose a hand-held device allowing increased spatial precision to uniformly illuminate an area of ​​the skin to be treated.

[0007] For this purpose, there is provided a handheld intense pulsed light device comprising a body configured to be held in the hand, said body having an opening receiving a treatment interface configured to be placed against a skin, the body housing a lamp adapted to emit a light pulse through the treatment interface in an emission direction, in which the treatment interface comprises a light guide projecting from the body of the handheld device, the light guide forming a polyhedron having opposite end faces in the emission direction and lateral faces connecting said end faces, the light guide having a thickness, between the end faces in the emission direction, greater than 6 mm, and the lateral faces having a roughness with an arithmetic mean deviation Ra less than or equal to 3.2.

[0008] The device is advantageously completed by the following characteristics, taken alone or in any of their technically possible combinations: - the light guide has an end face having a surface extending along a short axis of between 15 mm and 30 mm, and a long axis of between 30 mm and 60 mm; - the light guide protrudes at least 5 mm from the body; - the side faces have a roughness with an arithmetic mean deviation Ra greater than 0.2; - a surface condition of the side faces results from cutting the light guide in glass; - the hand-held device further comprises an opaque cover surrounding the side faces; - the light guide is formed from a material having a refractive index greater than 1.45; - the handheld device comprises a filter arranged between the lamp and the light guide, configured to filter at least wavelengths below 580 nm, the filter and the light guide being formed from different materials; - the light guide is formed from a glass block.

[0009] The invention also relates to an intense pulsed light system comprising a hand-held device according to the invention, and a console to which said hand-held device is connected. PRESENTATION OF THE FIGURES

[0010] The invention will be better understood, thanks to the following description, which relates to embodiments and variants according to the present invention, given as non-limiting examples and explained with reference to the appended schematic drawings, in which:

[0011] [Fig. 1] [Fig. 1] shows in a simplified manner a hand instrument according to a possible embodiment of the invention;

[0012] [Fig.2] [Fig.2] schematically shows an illumination assembly comprising a lamp and a light guide according to a possible embodiment of the invention;

[0013] [Fig.3] [Fig.3] shows the whole of [Fig.2] from a different angle;

[0014] [Fig.4] [Fig.4] schematically shows an illumination assembly comprising a lamp, a light guide and a cover according to a possible embodiment of the invention

[0015] [Fig.5] [Fig.5] shows the whole of [Fig.4] from a different angle;

[0016] [Fig.6] [Fig.6] is a graph illustrating the distribution of the luminous flux along a long axis at the output of the light guide, according to several configurations of the hand-held device;

[0017] [Fig.7] [Fig.7] is a graph illustrating the distribution of luminous flux along of a short axis at the output of the light guide, according to several configurations of the hand-held device. Detailed description

[0018] With reference to [Fig.l], the handheld intense pulsed light device 1 comprises a body 2 configured to be held in the hand. The handheld device 1 is typically connected to a console, and therefore comprises a wired connector 4 enabling the handheld device 1 to be supplied with electricity. The console integrates all the electronics necessary for charging and discharging high-voltage capacitors (typically 300 to 1000 V). The wired connector 4 may also integrate water circulation between the console and the handheld device 1 for cooling purposes. The console also integrates adjustment means enabling the parameters of the light pulse (duration, intensity, etc.) to be adjusted.

[0019] The body 2 has an opening receiving a treatment interface 8 configured to be placed against a skin, that is to say in contact with this skin or at least very close to it (less than 1 cm). The treatment interface 8 comprises a light guide 10 projecting from the body 2 of the hand-held device 1, in the emission direction. Preferably, the light guide 10 projects at least 5 mm from the body 2, and preferably at least 7 mm. The projection of the light guide 10 is understood to be the height to which the light guide 10 rises relative to the wall of the body 2 which surrounds the light guide 10 in the emission direction.

[0020] In this example, the treatment interface 8 comprises a cover 12 surrounding the light guide 10, in particular at the periphery of the opening of the body 2. The cover 12 leaves a face 10a of the light guide 10 free in a direction of emission of the light, which is the face 10a intended to be placed against the skin.

[0021] With reference to [Fig.2] and [Fig.3] illustrating an illumination assembly, the body 2 of the hand-held apparatus 1 houses a lamp 14 adapted to emit a light pulse through the processing interface 8 in an emission direction. The lamp 14 is preferably a flash lamp. Upon emission of a light pulse, a high voltage discharges through the lamp 14 emitting high-energy light (10 to 200 Joules) for a very short time (1 to 10 ms) and over a broad wavelength spectrum (400 to 1200 nm). In the example illustrated, the lamp 14 takes a U-shape, the part which emits the useful light being located in the junction 15 of the branches of this U, at which a reflector 16 surrounds the lamp 14 except in the emission direction. The reflector 16 makes it possible to return to the output of the processing interface 8 rays which would otherwise heat the body 2 of the hand-held device 1.Typically, the reflector 16 is an opaque, reflective or at least white part in order to return the light, and preferably very diffusing in order to homogenize the returned light. Preferably, the hand-held device 1 is configured to accommodate a circulation of water in contact with the lamp 14, and preferably between the reflector 16 and the lamp 14.

[0022] The illumination assembly typically comprises a filter 18 arranged at the output of the lamp 14 in the illumination direction, to reduce the spectrum of the emitted light depending on the applications. Preferably, such a filter 18 is configured to filter the wavelengths of the light pulse less than 580 nm (cutoff frequency or transmittance less than 0.1), and preferably less than 600 nm. For example, the filter 18 is a SCHOTT RG-610 high-pass filter with a cutoff frequency of 610 nm. The filtering of the low frequencies makes it possible in particular to reduce the sensitivity of the light stimulation to the skin tone. Typically, the filter 18 is flat and has a thickness of 1 to 4 mm, preferably less than 3 mm.

[0023] A light guide 10 is arranged after the filter 18 in the emission direction. The light guide 10 forms a polyhedron having opposite end faces 10a in the emission direction and lateral faces 10b connecting said end faces 10a. Typically, the light guide 10 is a hexahedral prismatoid with quadrilateral faces, and more precisely a cuboid such as the right block illustrated. The light guide has a thickness, in the emission direction, greater than 6 mm, and preferably greater than 8 mm, and more preferably greater than 11 mm. The thickness must be sufficient to allow a homogeneous distribution of the light over the area to be treat. However, it should not be too long so as not to reduce the transmitted energy too much. Preferably, the thickness is less than 30 mm.

[0024] By way of example, the end face 10a may have a surface extending along a short axis of between 15 mm and 30 mm, and a long axis of between 30 mm and 60 mm.

[0025] As illustrated in [Fig.4] and [Fig.5], the cover 12 can cover the side faces 10b of the light guide 10. The cover 12 makes it possible to protect against danger in the light diffused by the side faces 10b of the light guide 10 without modifying either the final energy transmitted or the transverse profile of the transmitted light. In fact, the cover 12, or at least a part of it, projects relative to the body 2 of the hand-held device 1 in the emission direction, preferably at the same height as the light guide 10. A part of the cover 12 is housed in the body 2.

[0026] The light guide 10 is made of a transparent material, capable of allowing the illumination energy to pass through. Typically, the light guide 10 is formed from a single piece. Preferably, the light guide 10 is made of glass, and for example of borosilicate glass such as N-BK7 or a so-called dense flint glass such as SF11 from Schott. Preferably, the light guide has a high optical index, that is to say a refractive index greater than 1.45, preferably greater than 1.51, and preferably greater than 1.60, and even more preferably greater than 1.70. Having a glass with a high optical index makes it possible to have a greater total internal reflection, and therefore makes it possible to have better guiding of the light in the emission direction to reduce energy losses and avoid having light emission through the side faces 10b, which could be dangerous.Preferably, the filter 18 and the light guide 10 are formed from different materials.

[0027] In order to ensure not only uniform treatment of the area to be treated, but also to ensure that the entire area receiving the light receives sufficient light to guarantee precise location of the treatment, it is important to ensure that the output transverse emission profile is as uniform as possible. In this respect, the surface condition of the lateral faces 10b of the light guide can be used to improve the consistency of the transverse emission profile.

[0028] [Fig.6] shows the distribution of the luminous flux along a long axis at the output of the light guide, according to several configurations of the hand-held device, while [Fig.7] shows it along a short axis. The abscissa axes are in millimeters, while the ordinate axis is in arbitrary measurement representative of the average intensity, on an axis perpendicular to the abscissa axis, of the energy received on a reception zone.

[0029] The first curve 30 in continuous lines corresponds to the transverse emission profile of a hand-held device 1 without light guide 10 or cover 12. The second curve 32 in dashed and dotted lines correspond to the transverse emission profile of a handheld device 1 with a light guide 10 and cover 12, the light guide 10 having rough side faces 10b. The third dotted curve 34 corresponds to the transverse emission profile of a handheld device 1 with a light guide 10 and cover 12, the light guide 10 having smooth side faces 10b. The fourth dashed curve 36 corresponds to the transverse emission profile of a handheld device 1 with a light guide 10 and cover 12, the light guide 10 having diffusing side faces 10b. It should be noted that the presence or absence of a cover 12 does not change the results, so no configuration with a light guide 20 but without a cover 12 has been shown. In all configurations, the shapes and materials of the light guide 10 are the same (47 mm by 19 mm block in BK7).

[0030] It is first noted that a hand-held device 1 without a light guide 10 has a transverse emission profile (first curve 30) varying enormously with the abscissa, both on the long axis and on the short axis, with a bell shape, which is not desirable. A hand-held device 1 with a light guide 10 with rough lateral faces has a transverse emission profile (second curve 32) which varies less, but which takes significantly lower values, indicating a significant loss of energy. A hand-held device 1 with a light guide 10 with smooth lateral faces has a transverse emission profile (third curve 34) which is practically flat and with higher values ​​than those obtained with rough faces. A low roughness of the lateral faces therefore makes it possible to increase both the constancy of the transverse emission profile and the quantity of energy transmitted, thus limiting losses.

[0031] It appears, however, that the lateral faces do not necessarily need to be smooth for the light guide 10 to have satisfactory characteristics. A hand-held device 1 with a light guide 10 with diffusing lateral faces has a transverse emission profile (fourth curve 36) with qualities similar to those obtained with smooth faces, both in terms of the flatness of the transverse emission profile and in terms of the quantity of energy transmitted.

[0032] A smooth face is obtained by polishing this face after cutting the material of the light guide 10, and therefore has a roughness with an arithmetic mean deviation Ra less than or equal to 0.2. A diffusing lateral face is obtained by retaining the surface condition after cutting the material of the light guide 10, or with minimal polishing, and has a roughness with an arithmetic mean deviation Ra less than or equal to 3.2. A rough face designates a face with a roughness with an arithmetic mean deviation Ra strictly greater than 3.2. Such roughness is for example obtained by means of a surface treatment of the lateral faces 10b such as frosting or sandblasting.

[0033] Thus, the use of a light guide 10 with side faces having a roughness with an arithmetic mean deviation Ra less than or equal to 3.2 makes it possible to obtain the desired precision qualities. Since each intervention involves costs, it is preferable to use a light guide 10 made of cut and raw glass without polishing or treatment since polishing does not make it possible to obtain gains justifying the additional costs. Consequently, the side faces 10b preferably have a roughness with an arithmetic mean deviation Ra greater than 0.2, and preferably greater than 0.5. Preferably, the surface condition of the side faces results from cutting the light guide 10 from glass.

[0034] The invention is not limited to the embodiment described and shown in the attached figures. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. A handheld intense pulsed light apparatus (1) comprising a body (2) configured to be held in the hand, said body (2) having an opening receiving a treatment interface (8) configured to be placed against skin, the body (2) housing a lamp (14) adapted to emit a light pulse through the treatment interface (8) in an emission direction, characterized in that the treatment interface (8) comprises a light guide (10) projecting from the body (2) of the handheld apparatus (1), the light guide (10) forming a polyhedron having opposite end faces (10a) in the emission direction and lateral faces (10b) connecting said end faces, the light guide (10) having a thickness, between the end faces (10a) in the emission direction, greater than 6 mm, and the lateral faces (10b) having a roughness with a arithmetic mean deviation Ra less than or equal to 3.2 and greater than 0.

2.

2. A handheld apparatus according to any preceding claim, wherein the light guide (10) has an end face (10a) having a surface extending along a short axis of between 15 mm and 30 mm, and a long axis of between 30 mm and 60 mm.

3. A handheld apparatus according to any preceding claim, wherein the light guide (10) projects at least 5 mm from the body (2).

4. Hand-held apparatus according to any one of the preceding claims, wherein the side faces (10b) have a roughness with an arithmetic mean deviation Ra greater than 0.

5.

5. A handheld apparatus according to any preceding claim, wherein the light guide is formed from cut and raw glass without polishing or processing.

6. A hand-held apparatus according to any preceding claim, further comprising an opaque cover (12) surrounding the side faces (10b).

7. A handheld apparatus according to any preceding claim, wherein the light guide (10) is formed from a material having a refractive index greater than 1.45

8. A hand-held apparatus according to any preceding claim, comprising a filter (18) disposed between the lamp and the light guide. (10), configured to filter at least wavelengths below 580 nm, the filter (18) and the light guide (10) being formed from different materials.

9. A handheld apparatus according to any preceding claim, wherein the light guide (10) is formed from a glass block.

10. An intense pulsed light system comprises a handheld apparatus according to any preceding claim, and a console to which said handheld apparatus is connected.

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