WO2024101365A1

WO2024101365A1 - Skin treatment device

Info

Publication number: WO2024101365A1
Application number: PCT/JP2023/040106
Authority: WO
Inventors: 知司小杉; 一範山中; 正志東平
Original assignee: ヤーマン株式会社
Priority date: 2022-11-07
Filing date: 2023-11-07
Publication date: 2024-05-16

Abstract

A light irradiation device 1 comprises an IPL 31 as a first light source that generates light of a predetermined wavelength, an LED 37 as a second light source that generates light of a wavelength different from the predetermined wavelength of the IPL 31, a first output surface 411 from which the light from the IPL 31 is output, and a second output surface 421 from which the light from the LED 37 is output. A path along which the light from the IPL 31 travels to reach the first output surface 411 and a path along which the light from the LED 37 travels to reach the second output surface 421 do not intersect with each other.

Description

Skin treatment device

This disclosure relates to a skin treatment device.

A known conventional technology for irradiating light onto the skin surface for beauty purposes is a light-irradiating cosmetic device equipped with a light-emitting unit having a first light source unit with a predetermined wavelength spectrum, a second light source unit with a wavelength spectrum different from that of the first light source unit, and an emission port through which at least a portion of the electromagnetic waves emitted from the first light source unit and at least a portion of the electromagnetic waves emitted from the second light source unit are emitted when electromagnetic waves are emitted from the first light source unit and the second light source unit, respectively (Patent Document 1).

JP 2022-068686 A

　However, if various types of light could be irradiated onto the skin appropriately and efficiently, it would be convenient and we could expect stable, favorable results.

The present disclosure therefore aims to irradiate various types of light onto the skin appropriately and efficiently.

In one aspect, a skin treatment device is disclosed that includes a first light source that generates light of a predetermined wavelength, a second light source that generates light of a wavelength different from the predetermined wavelength of the first light source, a first exit surface from which the light from the first light source is emitted, and a second exit surface from which the light from the second light source is emitted, in which the path along which the light from the first light source reaches the first exit surface does not intersect with the path along which the light from the second light source reaches the second exit surface.

According to this disclosure, it is possible to irradiate the skin with various types of light appropriately and efficiently.

1 is a perspective view showing an overall appearance of a light irradiation device according to an embodiment of the present invention. FIG. 2 is a perspective view showing a configuration of a light irradiation unit of the light irradiation device of FIG. 1 . 3 is a vertical sectional perspective view showing the structure of the light irradiation unit in FIG. 2. FIG. 3 is a vertical cross-sectional view showing the structure of the light irradiation unit in FIG. 2 . 1. FIG. 4 is a perspective view showing another example of the configuration of the light irradiation unit of the light irradiation device of FIG. FIG. 6 is a vertical sectional perspective view showing the structure of the light irradiation unit in FIG. 5 . FIG. 6 is a vertical cross-sectional view showing the structure of the light irradiation unit in FIG. 5 . 2 is a block diagram showing an outline of a control system of the light irradiation device of FIG. 1 . FIG. 2 is a perspective view showing the overall appearance of a light irradiation device including a sensor unit. FIG. 10 is a plan view of the light irradiation device of FIG. 9 . 4 is an explanatory diagram of characteristics of light (predetermined light) emitted from an LED. FIG. FIG. 1 is a diagram showing test results (part 1) concerning the melanin production suppression effect by irradiation with green LED light. FIG. 13 is a diagram showing test results (part 2) concerning the melanin production suppression effect by irradiation with green LED light. FIG. 13 is a diagram showing test results (part 3) concerning the melanin production suppression effect by irradiation with green LED light. FIG. 13 is a diagram showing test results (part 4) concerning the melanin production suppression effect by irradiation with green LED light. FIG. 5 is a diagram showing test results (part 5) concerning the melanin production suppression effect by irradiation with green LED light. FIG. 13 is a diagram showing test results (part 6) concerning the melanin production suppression effect by irradiation with green LED light. FIG. 17 is a table showing the evaluation results obtained from the test results of FIGS. 13A to 13E. FIG. 13 is a diagram showing test results (part 7) concerning the melanin production suppression effect by irradiation with green LED light. FIG. 13 is a diagram showing test results (part 8) concerning the melanin production suppression effect by irradiation with green LED light. FIG. 9 is a diagram showing test results (part 9) concerning the melanin production suppression effect by irradiation with green LED light. FIG. 10 is a diagram showing test results (part 10) concerning the melanin production suppression effect by irradiation with green LED light. 1 is a table showing the relationship between the radiation intensity of green LED light and the effect (the effect of suppressing melanin production). 1 is a graph (part 1) showing the relationship between the radiation intensity of green LED light and the effect. 2 is a graph (part 2) showing the relationship between the radiation intensity of green LED light and the effect. 13 is a graph (part 3) showing the relationship between the radiation intensity of green LED light and the effect. 13 is a graph showing another test result regarding the relationship between the radiant intensity of green LED light and the effect. FIG. 13 is a diagram showing test results (part 1) relating to differences in melanin production inhibitory effects caused by differences in wavelength. FIG. 13 is a diagram showing test results (part 2) relating to differences in melanin production inhibitory effects caused by differences in wavelength. FIG. 13 is a diagram showing test results (part 3) relating to differences in melanin production inhibitory effects caused by differences in wavelength. FIG. 1 shows test results regarding the expression level of keratin 10.

Each embodiment will be described in detail below with reference to the attached drawings. In the description of the present invention, the up-down direction is defined along each axis of a three-dimensional Cartesian coordinate system as shown in each drawing, and the upward and downward directions are defined according to the direction of the arrows, and the longitudinal direction and width direction are also defined. The longitudinal direction and width direction are mutually orthogonal within the same plane, and the up-down direction is mutually orthogonal to the longitudinal direction and width direction. A line of sight along the up-down direction is a planar view, and a cross section along the up-down direction is a longitudinal cross section.

The up-down direction is a direction perpendicular to the upper surface of the light transmitting section 41 of the light guide 4, which will be described later, and is also perpendicular to the upper surface of the filter 33, which will be described later. Therefore, the plan view is a line of sight along a direction perpendicular to the upper surface of the light transmitting section 41 of the light guide 4, which will be described later. The plan view is also a line of sight along a direction perpendicular to the surface of the user's skin when the skin treatment device is in use. The direction of light emitted from the head unit 3 is upward. The directions shown in each figure are merely for the sake of convenience in explaining the structure of each part of the skin treatment device according to the present invention, and are not related to the directions of the skin treatment device when the skin treatment device is in use (in other words, the posture of the skin treatment device).

(overall structure)
FIG. 1 is a perspective view showing the overall appearance of a light irradiation device 1 according to an embodiment, as an example of a specific configuration of a skin treatment device according to the present invention.

The light irradiation device 1 generates light that can be irradiated to human skin. The light may have a beauty-related effect on a human, particularly on the skin. In this case, the beauty-related effect is arbitrary and may include hair removal, skin beautification, elimination of sagging, tightening, fat burning, lifting, face slimming, improving skin firmness, luster, and moisture, or any combination of one or more of such effects. Furthermore, the beauty-related effect may be a quantifiable effect or may not be a quantifiable effect.

The light irradiation device 1 shown in FIG. 1 is a portable type that can be held by the user's hand, but the form of the skin treatment device (light irradiation device) according to the present invention is arbitrary, and may be a fixed type that is placed on a stand for use, or may be a movable type that is movably supported on a fixed device via an arm or the like. Furthermore, the skin treatment device (light irradiation device) according to the present invention may be in the form of a mask that is worn on the face, or a form that can be wrapped around the body for use, for example.

The light irradiation device 1 includes a grip portion 2 and a head portion 3. In this case, the user can locally irradiate light from the light irradiation device 1 to a desired area by holding the grip portion 2 in the hand and pointing the skin-facing portion 3a of the head portion 3 toward a desired area on the user's face or body.

The grip portion 2 has a shape that allows it to be easily held by the user's hand. The grip portion 2 may include an input section (not shown) that includes various buttons such as a power on/off button, a mode switching button, and an intensity adjustment button. The various buttons may be mechanical buttons or touch switches. The grip portion 2 may also be provided with a display section (not shown) that displays the status of the light irradiation device 1, etc.

The head portion 3 is provided at the end of the grip portion 2. The head portion 3 may be fixed to the grip portion 2, may be detachable, or may be movable relative to the grip portion 2. The head portion 3 (or a part of the head portion 3) may also include multiple attachments that can be attached to and detached from the grip portion 2.

The shape of the skin-facing portion 3a of the head portion 3 in a plan view (i.e., the shape when viewed in the vertical direction) can be any shape, such as a circle, an ellipse, a rectangle, a rounded rectangle, a polygon, or a rounded polygon.

The skin-facing portion 3a is formed in a concave shape in its longitudinal section (i.e., a section along the up-down direction) so that the light emission surface having beauty-related effects is the surface facing the user's skin and is recessed into the user's skin. The light emission surface of the skin-facing portion 3a is exposed, but because it is concave, it does not come into contact with the user's skin and does not get dirty.

(Light Irradiation Unit)
2 to 4 are diagrams showing the configuration and structure of the light irradiation unit 30 of the light irradiation device 1 according to the embodiment. The upper side of the light irradiation unit 30 faces the user's skin.

The light irradiation unit 30 is built into the head unit 3. Specifically, the light irradiation unit 30 is provided on the head unit 3 in such a manner that the upper end of the light irradiation unit 30 is exposed from the upper end of the head unit 3. Note that, although the light irradiation unit 30 is provided as a structure separated from the head unit 3 in the example shown in the figure, it may be configured as an integral part of the head unit 3.

The light irradiation unit 30 generates light that is irradiated onto the skin via the skin-facing portion 3a. That is, the light irradiation unit 30 irradiates light onto the skin via the skin-facing portion 3a.

The light irradiation unit 30 includes an IPL (Intense Pulsed Light) 31 as a first light source, a first reflector 32, a filter 33, a second reflector 35, an LED (Light Emitting Diode) 37 as a second light source, and a light guide 4.

The IPL 31, which serves as the first light source, is a light source that emits light of a specific wavelength that has a beauty-related effect.

One IPL 31 may be disposed, or multiple IPLs 31 may be disposed. When multiple IPLs 31 are disposed, the multiple IPLs 31 may be disposed, for example, side-by-side along the longitudinal or width direction.

The first reflector 32 is a reflector that reflects the light emitted from the IPL 31 and guides it upward.

The filter 33 is disposed above the IPL 31 and the first reflector 32, and passes the light emitted from the IPL 31 (including the light reflected by the first reflector 32), and cuts out light emitted from the IPL 31 that has a specific wavelength or less. The value (range) of the wavelength of the light cut by the filter 33 is not limited to a specific value, but is appropriately set, for example, taking into consideration the wavelength of light that has a beauty-related effect. The value (range) of the wavelength of the light cut by the filter 33 may be set to 400 nm, for example, so that the filter 33 cuts out light with a wavelength of 400 nm or less.

The light emitted from the IPL 31 may pass through one filter 33, or may pass through two or more types of filters. When two or more types of filters are provided, the two or more types of filters may cut different wavelengths of light. For example, each of the two or more types of filters may be a filter that cuts light below a specific wavelength, and the specific wavelengths may be different. When two or more types of filters are provided, an IPL 31 may be provided for each filter, or multiple control modes may be provided.

The light emitted from IPL 31 may be adjusted by a filter to, for example, light having a central wavelength in the wavelength range of 400 nm or more and 800 nm or less (in other words, roughly the visible light range), or in the wavelength range of 400 nm or more (in other words, roughly the visible light range or more).

The first reflector 32 and the filter 33 are held in a lower holder 34 arranged to surround the sides of the first reflector 32 and the filter 33. Specifically, the first reflector 32 is housed together with the IPL 31 in the generally peripheral wall-shaped (in other words, cylindrical) lower holder 34, and a flat filter 33 is arranged near the upper end of the lower holder 34 so as to cover the upper opening of the first reflector 32. The lower holder 34 is formed, for example, from resin, and is fixed to the head portion 3.

The second reflector 35 is a reflector that is disposed around the upper periphery of the filter 33 and reflects and guides the light of the IPL 31 that has passed through the filter 33. The second reflector 35 is a rounded rectangle with semicircular ends in the longitudinal direction in a plan view, and is formed as a peripheral wall above the filter 33 along the edge of the filter 33.

The second reflector 35 is held by the upper holder 36. Specifically, the peripheral wall-shaped upper holder 36 is disposed at the upper end of the peripheral wall-shaped (cylindrical) lower holder 34, with the lower edge of the upper holder 36 engaging with the upper edge of the lower holder 34. The peripheral wall-shaped second reflector 35 is attached to the inner surface (in other words, the inner wall surface) of the upper holder 36. The upper holder 36 is formed, for example, from silicone rubber, and is fixed to the upper end of the lower holder 34.

The second reflector 35 is disposed to better guide the light to the center of the light guide 4 by reflecting light that is inclined in the vertical direction among the light emitted from the IPL 31 and passed through the filter 33 (including the light reflected by the first reflector 32 and passed through the filter 33). However, it is not essential for the present invention to have a reflector above the filter 33, and the second reflector 35 does not have to be disposed.

The inner space of the second reflector 35 in a plan view and the plate surface of the filter 33 generally overlap each other in the vertical direction.

At least a portion of the light emitted from the IPL 31 is reflected by the first reflector 32 and passes through the filter 33, and at least a portion of the light is reflected by the second reflector 35 and guided to the light guide 4.

The LED 37 as the second light source is a light source that generates light of a specific wavelength that has a beauty-related effect. Specifically, when irradiated onto the skin, for example, it generates light that has an antibacterial effect to improve acne, an antioxidant effect and an effect of suppressing melanin production to improve spots, an effect of improving lymph flow and reducing swelling by repairing damaged cells, and an effect of improving wrinkles by promoting collagen production associated with activation of dermal fibroblasts. The wavelength of light generated by the IPL 31 as the first light source and the wavelength of light generated by the LED 37 as the second light source are mutually different.

A single LED 37 may be disposed, or multiple LEDs 37 may be disposed. When multiple LEDs 37 are disposed, the multiple LEDs 37 may be disposed, for example, side-by-side in a plane that is approximately parallel to the plate surface of the filter 33.

In this embodiment, the LEDs 37 are arranged in a plane parallel to the plate surface of the filter 33. Specifically, the LEDs 37 are arranged in a line on the upper surface of a holder flange 38 that is provided in a brim-like projection near the upper end of the outer surface (in other words, the outer wall surface) of the lower holder 34. The LEDs 37 are arranged so as to surround the upper opening of the lower holder 34 in a plan view, and further so as to surround the upper openings of the IPL 31 and the first reflector 32. The holder flange 38 is formed, for example, from silicone rubber, and is fixed to a position near the upper end of the outer surface (outer wall surface) of the lower holder 34.

In the example shown in the figure, the LEDs 37 are arranged around the entire periphery of the upper end opening of the lower holder 34 in a plan view, surrounding the entire periphery of the IPL 31, but the LEDs 37 may be arranged around at least a portion of the periphery of the IPL 31 in a plan view. For example, the LEDs 37 may be arranged on both or only one of the longitudinal sides of the IPL 31 in a plan view, or on both or only one of the widthwise sides.

Multiple LED elements may be mounted on one chip. Also, multiple (i.e., multiple types of) LED elements having mutually different center wavelengths may be mounted on one chip.

The LED 37 may generate light having a central wavelength in the wavelength range of 430 nm or more and 480 nm or less. By irradiating the light of the IPL 31 and the light of the LED 37 having a central wavelength in the wavelength range of 430 nm or more and 480 nm or less alternately or simultaneously, it is expected that acne will be improved due to the antibacterial effect.

The LED 37 may also emit light having a central wavelength in the wavelength range of 490 nm or more and 525 nm or less. By alternately or simultaneously irradiating the light of the IPL 31 and the light of the LED 37 having a central wavelength in the wavelength range of 490 nm or more and 525 nm or less, it is expected that the penetration of whitening ingredients will be promoted and blemishes will be improved by the antioxidant effect and the melanin production inhibition effect.

The LED 37 may also emit light having a central wavelength in the wavelength range of 530 nm or more and 600 nm or less. By alternately or simultaneously irradiating the light of the IPL 31 and the light of the LED 37 having a central wavelength in the wavelength range of 530 nm or more and 600 nm or less, it is expected that lymph flow will improve and swelling will be reduced by repairing damaged cells.

The LED 37 may also emit light having a central wavelength in the wavelength range of 610 nm or more and 650 nm or less. By alternately or simultaneously irradiating the light of the IPL 31 and the light of the LED 37 having a central wavelength in the wavelength range of 610 nm or more and 650 nm or less, it is expected that as an anti-aging care, wrinkles will be improved by promoting collagen production due to the activation of fibroblasts in the dermis.

The LED 37 may also generate light having a central wavelength in the wavelength range of 800 nm or more and 2500 nm or less. By irradiating the light of the IPL 31 and the light of the LED 37 having a central wavelength in the wavelength range of 800 nm or more and 2500 nm or less alternately or simultaneously, a warming effect is expected.

The second light source (specifically, in this embodiment, LED 37) may generate any one of a plurality of lights having a central wavelength within any one of the above-mentioned wavelength ranges, or a combination of at least two of the plurality of lights.

It is also possible to arrange multiple types of LEDs that generate light with different center wavelengths and control them according to the mode. In this case, any one of the light from the multiple types of LEDs that generate light with different center wavelengths may be emitted, or the light from the multiple types of LEDs may be emitted alternately or simultaneously. In this case, multiple types of LED elements that generate light with different center wavelengths may be mounted on one chip, and the ratio of the numbers of each of the multiple types of LED elements on one chip may be set to an appropriate ratio as appropriate.

The LED 37 may be configured to irradiate light, for example, with a radiation intensity in the range of 0.5 mW/ ^cm2 or more and 62 mW/ ^cm2 or less, and more preferably with ^a radiation intensity in the range of 11.5 mW/ ^cm2 or more and 30 mW/ ^cm2 or less. The LED 37 may be configured to irradiate light with an irradiation energy in the range of 0.09 J/ ^cm2 or more and 30 J/cm2 or less, and more preferably with an irradiation energy in the range of 0.09 J/ ^cm2 or more and 11 J/ ^cm2 or less.

The light irradiation device 1 may be configured to freely switch between a plurality of modes by selecting the IPL 31 and the LED 37. Specifically, the light irradiation device 1 may be configured to freely switch between, for example, a skin beautifying mode, an anti-aging care mode, a daily care mode for daily use, a special care mode for use approximately two to three times a week, a mode for use on a large area such as the face, a spot care mode for areas of concern such as blemishes or dullness, and a mode for facial fine hair care and skin texture adjustment.

When the head unit 3 (or part of the head unit 3) is provided with multiple attachments that can be attached and detached to the grip unit 2, the attachments can be attached and detached using magnets or fitting parts, and may be attachments that include at least part of the configuration of the light irradiation unit 30. In this case, for example, by making the attachment include a filter 33 and an LED 37, it is possible to select a suitable configuration for the filter 33 and the LED 37 according to the purpose.

Alternatively, at least one of the IPL 31 and the LED 37 may remain on the grip 2/head 3 side, and the upper part of the light irradiation unit 30 may be configured as an attachment including the light guide 4 that comes into contact with the skin. In this case, it is possible to select an irradiation area such as wide area or spot care while keeping the cost of the light irradiation unit 30 components down.

In other words, the configuration included in the attachment that is detachable from the grip portion 2 is not limited to a specific configuration, and the attachment may include, for example, at least the light guide 4 out of the IPL 31 as the first light source, the LED 37 as the second light source, and the light guide 4, or may include at least the LED 37 as the second light source and the light guide 4.

The attachment that is detachable from the grip unit 2 may be configured so that the type of attachment attached to the head unit 3 (or part of the head unit 3) can be identified. The identification unit may be realized, for example, based on a magnetic sensor, a contact-type sensor, switching, etc., and by automatically identifying the attachment, appropriate processing can be performed without the need to operate a button, etc.

(Light guide)
The light irradiation device 1 of the embodiment comprises an IPL 31 as a first light source that generates light of a predetermined wavelength, an LED 37 as a second light source that generates light of a wavelength different from the predetermined wavelength of the IPL 31, a first exit surface 411 from which the light from the IPL 31 is emitted, and a second exit surface 421 from which the light from the LED 37 is emitted, and the path along which the light from the IPL 31 reaches the first exit surface 411 and the path along which the light from the LED 37 reaches the second exit surface 421 do not intersect, and the second exit surface 421 is inclined with respect to the first exit surface 411.

As shown in FIG. 4, the light irradiation unit 30 has a path and an exit surface corresponding to each of the two types of light. Specifically, the light irradiation unit 30 has a path AR1 corresponding to the light of the IPL 31 and a first exit surface 411 which is an exit surface corresponding to the light of the IPL 31, and a path AR2 corresponding to the light of the LED 37 and a second exit surface 421 which is an exit surface corresponding to the light of the LED 37.

The light guide 4 is interposed between the IPL 31 as the first light source and the LED 37 as the second light source and the user's skin, and is configured to collect the light of the LED 37 in the center in a plan view on the user's skin side and irradiate the light of the LED 37 within the light irradiation surface of the IPL 31. In a plan view, the light guide 4 has a light passing section 41 in the center and a ring-shaped light guide section 42 that surrounds the periphery of the light passing section 41. In other words, the light passing section 41 and the light guide section 42 of the light guide 4 do not overlap each other in a plan view. The light guide 4 is formed, for example, from a transparent resin or glass.

In the example shown in the figure, the light guide 42 is disposed around the entire periphery of the light passing portion 41 in a plan view, so as to completely surround the periphery of the light passing portion 41, but the light guide 42 may be disposed around at least a portion of the periphery of the light passing portion 41 in a plan view, for example, to match the portion where the LED 37 is disposed in a plan view. In other words, the light guide 42 may be disposed around at least a portion of the periphery of the IPL 31 in a plan view.

The light passing portion 41 is formed in a flat plate shape, and the light guide portion 42 is formed in a generally peripheral wall shape (in other words, cylindrical shape) that surrounds the periphery of the light passing portion 41. The flat light passing portion 41 is provided inside the peripheral wall-shaped (cylindrical) light guide portion 42, in the middle in the vertical direction, so as to be supported by the inner peripheral surface of the light guide portion 42.

The light transmitting portion 41 of the light guide 4 overlaps with the IPL 31 and the filter 33 in the vertical direction. In particular, the plate surface of the light transmitting portion 41 of the light guide 4 and the plate surface of the filter 33 generally overlap with each other in the vertical direction.

The light guide section 42 of the light guide 4 surrounds the sides (in other words, the periphery) of the upper holder 36, and its lower end face faces the array of the multiple LEDs 37 that surround the upper end opening of the lower holder 34 in the vertical direction, covering the upper side (upper surface) of the array of the multiple LEDs 37. In other words, the light guide section 42 surrounds the sides (in other words, the periphery) of the IPL 31, the filter 33, and the light transmitting section 41 in the vertical direction, and overlaps with the LEDs 37.

The light passing section 41 and the light guiding section 42 of the light guide 4 may be formed as an integrated part (in other words, a single continuous member or component) as in the example shown in the figure, or may be formed as separate parts (in other words, multiple components).

When the light passing portion 41 and the light guiding portion 42 are formed as separate parts (multiple members), they may be formed from the same material, or may be formed from materials different from each other. When the light passing portion 41 and the light guiding portion 42 are formed as separate parts (multiple members), as shown in Figures 5 to 7, a shielding member or shielding film that does not allow light to pass (i.e., optically separates the light passing portion 41 and the light guiding portion 42) may be disposed between the light passing portion 41 and the light guiding portion 42 as a light shielding portion 43.

When the light passing portion 41 and the light guide portion 42 are formed as separate parts (multiple members), a space may be provided at least partially between the light passing portion 41 and the light guide portion 42. When a space is provided between the light passing portion 41 and the light guide portion 42 over the entire circumference thereof in a plan view, it is expected that light will not pass between the light passing portion 41 and the light guide portion 42. In this case, the light passing portion 41 may be supported by the upper holder 36. In this case, or alternatively, a support part may be provided at least partially between the light passing portion 41 and the light guide portion 42, made of a material that does not allow light to pass therethrough, to support the light passing portion 41 against the inner surface of the light guide portion 42.

In addition, at least one of the second reflector 35 and the upper holder 36 in the example shown in the figure may be extended upward to optically separate the part/member corresponding to the light passing section 41 from the part/member corresponding to the light guiding section 42.

The upper surface of the light passing section 41 of the light guide 4 (i.e., the surface facing the user's skin) constitutes a first exit surface 411 from which light from the IPL 31 is emitted. The upper end surface of the light guiding section 42 of the light guide 4 (i.e., the end surface facing the user's skin) constitutes a second exit surface 421 from which light from the LED 37 is emitted. The upper surface of the light guide 4 (i.e., the surface facing the user's skin), that is, in a plan view, has the first exit surface 411 in the center and a second exit surface 421 that surrounds the periphery of the first exit surface 411.

In the example shown in the figure, the second exit surface 421 is formed all around the first exit surface 411 in a plan view, surrounding the entire periphery of the first exit surface 411, but the second exit surface 421 may be formed on at least a portion of the periphery of the first exit surface 411 in a plan view, for example, to match the portion where the LED 37 is arranged in a plan view. In other words, the second exit surface 421 may be formed on at least a portion of the periphery of the IPL 31 in a plan view.

The contact portion 44 is the outer edge of the second emission surface 421, and comes into contact with the user's skin when the light irradiation device 1 is in use. The contact portion 44 also corresponds to the outer periphery of the skin-facing portion 3a. With the contact portion 44 in contact with the skin, the light irradiation device 1 is moved appropriately, and the light of the IPL 31 and the light of the LED 37 are irradiated onto the user's skin, thereby providing a beauty-related effect.

The second exit surface 421, which is the upper end surface of the light guide section 42 of the light guide 4, slopes downward from an outer edge portion (i.e., contact portion 44) located above the periphery of the first exit surface 411 in a plan view toward the periphery of the first exit surface 411, forming a bank portion of the concave skin-facing portion 3a. In the example shown in the figure, the second exit surface 421 has a downward slope toward the first exit surface 411 and is formed into a slightly convex curved surface.

When the light irradiation device 1 is in use, the first emission surface 411 is parallel to the user's skin surface and faces directly against the skin surface, while the second emission surface 421 is inclined relative to the first emission surface 411 and, by extension, inclined relative to the user's skin surface.

At least a portion of the light emitted from the IPL 31 is reflected by the first reflector 32 and passes through the filter 33, and at least a portion of the light is reflected by the second reflector 35 and guided to the center of the light guide 4, passes through the light passing portion 41 of the light guide 4, and is emitted from the first exit surface 411.

The light emitted from the LED 37 enters the light guide section 42 of the light guide body 4, is guided by the light guide section 42 (in other words, passes through the light guide section 42), and is emitted from the second emission surface 421.

At this time, the path along which the light from the IPL 31 reaches the first exit surface 411 of the light passing section 41 (in other words, the path of the light from the IPL 31 to the first exit surface 411) and the path along which the light from the LED 37 reaches the second exit surface 421 of the light guide section 42 (in other words, the path of the light from the LED 37 to the second exit surface 421) do not intersect with each other.

In addition, since the second exit surface 421, which is the upper end surface of the light guide 42, is inclined relative to the first exit surface 411, which is the upper surface of the light passing portion 41 of the light guide 4, the light passing through the light guide 42 is refracted at the second exit surface 421, and the light of the IPL 31 which passes through the light passing portion 41 and is emitted from the first exit surface 411 and the light of the LED 37 which passes through the light guide 42 and is emitted from the second exit surface 421 are irradiated onto approximately the same area of the user's skin (i.e., the light of the IPL 31 which is emitted from the first exit surface 411 and the light of the LED 37 which is emitted from the second exit surface 421 intersect). This allows the light of the IPL 31 that passes through the light passing section 41 and is emitted from the first emission surface 411 and the light of the LED 37 that passes through the light guide section 42 and is emitted from the second emission surface 421, i.e., multiple types of light with different wavelengths, to be irradiated alternately or simultaneously onto approximately the same area of the user's skin, making it possible to efficiently impart multiple types of beauty-related effects to the user's skin.

In order to prevent the path of the light of the IPL 31 passing through the space surrounded by the light guide 42 of the light guide 4 of the light guide body 4 and the light passing section 41 to the first emission surface 411 from intersecting with the path of the light of the LED 37 passing through the light guide 42 of the light guide body 4 to the second emission surface 421, it is preferable to provide a shielding member or shielding film that does not allow light to pass between the space surrounded by the light guide 42 and the inside of the light guide 42, such as the upper holder 36 in the example shown in the figure (i.e., optically separates the space surrounded by the light guide 42 from the inside of the light guide 42). For example, when the second reflector 35 is not provided, it is preferable to install the upper holder 36 or extend the lower holder 34 upward. In addition, the space surrounded by the light guide 42 is a space that roughly overlaps with the plate surface of the filter 33 in the vertical direction (in other words, in a plan view).

(Control system)
FIG. 8 is a block diagram showing an outline of a control system of the light irradiation device 1. As shown in FIG.

The light irradiation device 1 includes a control device 8, which is electrically connected to a power source 9, an IPL 31 as a first light source, and an LED 37 as a second light source. The control device 8 and the power source 9 are housed, for example, inside the grip portion 2.

The control device 8 operates based on power from the power source 9 and controls the IPL 31 and the LED 37. The IPL 31 and the LED 37 operate based on power from the power source 9 under the control of the control device 8. The power source 9 may include an external power source and/or an internal power source. The internal power source may be a rechargeable battery.

The control device 8 includes an IPL driver 81 and an LED driver 82. The IPL driver 81 controls the IPL 31 to emit light at predetermined intervals by supplying power from the power source 9. The LED driver 82 controls the LED 37 to emit light by supplying power from the power source 9.

The IPL driver 81 and the LED driver 82 may be controlled to irradiate the light of the IPL 31 and the light of the LED 37 simultaneously, or may be controlled not to irradiate them simultaneously (i.e., to irradiate them alternately). Simultaneous irradiation of the light of the IPL 31 and the light of the LED 37 can obtain multiple effects in a short time. On the other hand, by irradiating the light of the IPL 31 and the light of the LED 37 alternately, rather than irradiating them simultaneously, it is possible to perform processing specialized for a specific purpose. For example, the LED 37 may be turned off 0.1 to 0.2 seconds before the IPL 31 is irradiated, and the irradiation of the LED 37 may be turned on again after the IPL 31 is irradiated, so that individual processing of the IPL 31 and the LED 37 is repeated within one mode. The control within one mode is not limited to this, and suitable control may be performed according to the purpose.

(Sensor section)
9 and 10, the light irradiation device 1 may include a sensor unit 5 for determining the condition of the user's skin in the vicinity of the light irradiation unit 30 (specifically, the second emission surface 421 of the light guide unit 42 of the light guide 4). In the example shown in the figures, the sensor unit 5 is provided on both sides in the width direction of the skin facing portion 3a in a plan view, in other words, on both sides in the width direction of the light guide 4.

In the example shown in the figure, the sensor unit 5 is arranged on both sides in the width direction of the skin-facing portion 3a in a planar view, but the sensor unit 5 may be arranged on both sides in the longitudinal direction, or only on one side, or only on one side in the width direction, of the skin-facing portion 3a in a planar view.

The sensor unit 5 has a light-emitting element 52 mounted on the upper surface of the substrate 51 as a light-emitting unit that generates test light, a light-receiving element 53 as a light-receiving unit that receives the test light reflected by the user's skin, and an opening 54 through which the light emitted from the light-emitting element 52 and the light incident on the light-receiving element 53 pass.

The light-emitting element 52 as a light-emitting section is specifically composed of a light-emitting diode. The wavelength of the inspection light emitted from the light-emitting element 52 is not limited to a specific wavelength, but is preferably a wavelength that has good sensitivity to changes in the degree of reflection depending on the presence or absence and the density of skin blemishes. The inspection light emitted from the light-emitting element 52 may be, for example, light having a central wavelength in the wavelength range of visible light, specifically light having a central wavelength in the wavelength range of 380 nm or more and 780 nm or less.

White light may be used as the inspection light. However, the inspection light is not limited to white light, and light of a color other than white light may be used as the inspection light, for example, light whose degree of reflection changes significantly depending on the presence or absence and the darkness of skin blemishes, making it possible to accurately grasp the state of skin blemishes.

In addition, the light emitted from the LED 37 serving as the second light source of the light irradiation unit 30 may be used as the inspection light, in which case the light emitting element 52 serving as the light emitting unit may not be provided.

The light-receiving element 53, which serves as a light-receiving unit paired with the light-emitting element 52, is specifically composed of a photodiode. A photodiode capable of detecting at least the inspection light emitted from the light-emitting element 52 is used as the light-receiving element 53. For example, a photodiode capable of detecting at least one of white light, R (red light), G (green light), and B (blue light) may be used as the light-receiving element 53.

The opening 54 is the portion that faces the user's skin, and may be made of any material that has excellent translucency and allows light to pass through, such as glass or polycarbonate.

When a voltage is applied to the light-emitting element 52, the light-emitting element 52 emits light and emits inspection light. The inspection light then reaches the user's skin surface through the opening 54, is reflected by the skin surface, and is incident on the light-receiving element 53 through the opening 54. The more inspection light that is incident on the light-receiving element 53 (in other words, the stronger the light), the larger the current that flows through the light-receiving element 53.

The amount of reflected test light varies depending on the color of the user's skin surface, specifically the amount of melanin in the user's skin. That is, if there is a lot of melanin and the skin is dark, the test light is absorbed relatively well by the skin surface, and the amount of reflected light is low. On the other hand, if there is little melanin and the skin is white, the amount of test light absorbed by the skin surface is relatively low, and the amount of reflected light is high. Therefore, in abnormal areas of the skin, such as blemishes caused by melanin, more test light is absorbed and the amount of reflected light is low compared to normal areas of the skin without blemishes. For this reason, skin abnormalities such as blemishes can be detected based on the amount of reflected light.

In consideration of the above, it is preferable that the inspection light emitted from the light-emitting element 52 be light of a wavelength that is easily absorbed by melanin, for example, since the difference in the amount of reflected light becomes large depending on the presence or absence and the darkness of skin blemishes.

Then, for example, the more melanin there is in the user's skin, the less light is reflected relative to the amount of inspection light emitted from the light-emitting element 52, and the less light is incident on the light-receiving element 53, which in turn reduces the current flowing through the light-receiving element 53.

The sensor unit 5 detects skin abnormalities such as blemishes based on the electrical output value output from the light receiving element 53 in response to the amount of light received by the light receiving element 53. Specifically, the sensor unit 5 determines the presence or absence and the darkness of blemishes on the skin, and judges the condition of the user's skin, for example, based on the value of the output voltage calculated as the product of the current flowing through the light receiving element 53 and the resistance placed in the negative feedback circuit.

The sensor unit 5 may determine the condition of the user's skin based on a time-series change in the electrical output value output from the light receiving element 53, or may determine the condition of the user's skin based on the relationship between the voltage applied to the light emitting element 52 and the electrical output value output from the light receiving element 53 (for example, the ratio between the voltage and the electrical output value).

The light irradiation device 1 adjusts the output intensity of the light irradiation unit 30 according to the user's skin condition determined by the sensor unit 5 while at least one of the IPL 31 as the first light source and the LED 37 as the second light source irradiates light. For example, a command is transmitted from the sensor unit 5 to the IPL drive unit 81 and the LED drive unit 82 of the control device 8. Based on the command transmitted from the sensor unit 5, the IPL drive unit 81 adjusts the power supplied from the power source 9 to the IPL 31 to adjust the light emission intensity of the IPL 31, and the LED drive unit 82 adjusts the power supplied from the power source 9 to the LED 37 to adjust the light emission intensity of the LED 37.

The light irradiation device 1 may, for example, increase the output of the light irradiation unit 30, specifically at least one of the IPL 31 and the LED 37, when the sensor unit 5 determines that there is a skin abnormality such as a blemish on the skin, and may stop the output of the light irradiation unit 30, specifically at least one of the IPL 31 and the LED 37, when the sensor unit 5 determines that there is no skin abnormality such as a blemish on the skin.

The light irradiation device 1 may also increase the output of the light irradiation unit 30, specifically the output of at least one of the IPL 31 and the LED 37, when the sensor unit 5 determines that the skin blemish is dark and the degree of abnormality is severe, and decrease the output of the light irradiation unit 30, specifically the output of at least one of the IPL 31 and the LED 37, when the sensor unit 5 determines that the skin blemish is light and the degree of abnormality is mild.

When adjusting the output of the light irradiation unit 30 as described above, the sensor unit 5 may determine the presence or absence and the degree of skin abnormalities such as blemishes based on a comparison with the base skin color of each user (i.e., the color of the skin part without skin abnormalities such as blemishes). In this case, for example, the head unit 3 of the light irradiation device 1 including the sensor unit 5 is abutted against a part of the skin with no or few skin abnormalities such as blemishes, and the electrical output value output from the light receiving element 53 at this time (referred to as the "base state"; it may also be the relationship between the voltage applied to the light emitting element 52 and the electrical output value output from the light receiving element 53 (for example, the ratio of the voltage to the electrical output value). The same applies below) is stored in a memory provided in, for example, the control device 8. The base state is data corresponding to a skin color with no or few skin abnormalities such as blemishes. Then, the light irradiation device 1 including the sensor unit 5 is operated to obtain the electrical output value output from the light receiving element 53 for each part of the skin while performing skin treatment (referred to as the "state of each part"). The base state and the state of each part are compared from time to time, and if the difference between the base state and the state of each part is equal to or greater than a preset condition (e.g., a threshold value), it may be determined that there is a skin abnormality such as a blemish, or that the degree of the skin abnormality such as a blemish is severe, and the output of the light irradiation unit 30 may be adjusted based on the determination result. Examples of parts of the skin that have no or few skin abnormalities such as blemishes include the forehead and face line (specifically, the area around the jawline).

When adjusting the output of the light irradiation unit 30 by comparing the base state with the state of each part as described above, the base state is stored and set before starting skin treatment, and when it is determined during skin treatment that the skin color is whiter than the base state (in other words, there are no or few skin abnormalities such as blemishes), the electrical output value output from the light receiving element 53 at that time may be stored as a new base state, for example in a memory provided in the control device 8. In other words, the base state may be updated (in other words, calibrated) as appropriate when it is determined that the skin color is whiter than the current base state.

When the output of the light irradiation unit 30 is adjusted by comparing the base state with the state of each part as described above, the base state may be acquired and appropriately updated (appropriately calibrated) while skin treatment is being performed, without storing the base state before skin treatment begins. That is, the electrical output value output from the light receiving element 53 when skin treatment begins may be stored in a memory provided in the control device 8 as the (initial) base state, and then, as skin treatment proceeds, when it is determined that the skin color is whiter than the base state stored at that time (in other words, there are no or few skin abnormalities such as blemishes), the electrical output value output from the light receiving element 53 at that time may be stored in a memory provided in the control device 8 as the new base state.

By comparing the base state with the state of each part, the output of the light irradiation unit 30 can be appropriately adjusted to match the skin color of each user. In other words, the output of the light irradiation unit 30 can be appropriately adjusted without being affected by differences in skin color between users, making it possible to perform even better skin treatment.

In addition, when the sensor unit 5 for determining the condition of the user's skin is provided near the light irradiation unit 30 (specifically, the second emission surface 421 of the light guide unit 42 of the light guide 4), and the head unit 3 (or part of the head unit 3) includes multiple attachments that can be attached to and detached from the grip unit 2, the attachments may include, for example, at least the light guide 4 out of the IPL 31 as the first light source, the LED 37 as the second light source, the light guide 4, and the sensor unit 5, or may include at least the LED 37 and the light guide 4 as the second light source.

In this embodiment, as described above, LEDs 37 can be arranged according to the purpose, but for certain applications, it is preferable to use green LEDs. This will be explained in detail below with reference to Figure 11 onwards.

FIG. 11 is an explanatory diagram of the characteristics of the light emitted from the LED 37 (hereinafter also referred to as "predetermined light"), with the horizontal axis representing the wavelength and the vertical axis representing the intensity, and shows an example of the characteristics.

The LED 37 is preferably a light source that generates a predetermined light having a central wavelength in a wavelength range longer than 490 nm and equal to or less than 525 nm. The basis (technical significance) of the superiority of this wavelength range (and the wavelength of approximately 505 nm within it) will be described later with reference to Figures 12A, 12B, and 20 onwards. Note that 505 nm and its vicinity are strictly blue-green wavelengths, and 525 nm and its vicinity are strictly green wavelengths, but hereinafter the wavelength range longer than 490 nm and equal to or less than 525 nm may be referred to as "green".

More preferably, the specified light has a central wavelength of approximately 505 nm, as shown in FIG. 11. With such a central wavelength, melanin production in the irradiated area of the user's skin can be suppressed more effectively than in the case where the specified light is not irradiated, as described below. For example, the specified light can be irradiated in a manner that has a better melanin production suppression effect in the irradiated area of the user's skin than when the specified light is not irradiated, by 5% or more, and more preferably by 10% or more.

The predetermined light preferably has a half-width at half maximum (see FIG. 11) of ±20 nm or less, and more preferably about ±10 nm. This maximizes the effect of suppressing melanin production in the irradiated area of the user's skin.

The light irradiation unit 30 irradiates the predetermined light preferably at a radiation intensity in the range of 0.5 mW/cm ² or more and 62 mW/cm ² or less, more preferably at a radiation intensity in the range of 11.5 mW/cm ² or more and 30 mW/cm ² or less. The test results regarding this will be described later with reference to FIG. 16 and subsequent figures.

Moreover, the light irradiating section 30 preferably irradiates the predetermined light with irradiation energy in the range of 5 J/cm ² or more and 30 J/cm ² or less.

It is also possible to implement multiple LED 37 elements on a single chip. Alternatively, LED 37 may be combined with other LEDs having other central wavelengths to form a single chip. For example, when LED 37 and a red LED are combined into a single chip LED, the ratio of the number of green LEDs to red LEDs on one chip may be appropriately adapted.

The control device 8 irradiates the skin with a predetermined light via the LED 37. At this time, the control device 8 may achieve continuous light irradiation for 1 minute or more, with the irradiation time of the predetermined light accounting for 1/2 or more.

The control device 8 may also control the emission of light from the head unit 3 in one or more operating modes. The one or more operating modes may include a predetermined operating mode associated with the melanin production suppression effect, or a predetermined operating mode associated with an effect related to the melanin production suppression effect. In this case, the control device 8 causes the head unit 3 to output a predetermined light in the predetermined operating mode.

Next, the effect of the above-mentioned specified light (the effect of suppressing melanin production) will be further explained with reference to test results, etc.

Because visible light is minimally invasive to the body, various studies have been conducted on its effects on the body with the aim of applying it to the medical and cosmetic dermatology fields (Imagawa et al., Japan Medical Journal, 32, 444 (2012)). For example, it has been reported that red light prevents skin aging, while green and yellow light play an important role in suppressing excessive cell activity.

Melanin, the pigment that causes pigmentation in the skin, is produced in melanocytes and plays an important role in preventing DNA damage from harmful ultraviolet rays. However, it is also the cause of spots, and there is a high demand for improving this. Therefore, we conducted an experiment to verify the effectiveness of green LED light, which suppresses cellular activity, to see if it also affects melanoma activity and reduces melanin production.

The inventors of this application requested Toin University of Yokohama to carry out the following test in order to verify the melanin production inhibitory effect of green LEDs. The melanin production inhibitory effect was verified using mouse-derived B164A5 cells (B16 melanoma cells, Riken BRC) and human-derived melanoma cells (HMV-II cells, KAC Co., Ltd.) obtained at the university. In addition, Ushio Electric's SMT525 (wavelength 525 nm) and SMT505 (wavelength 505 nm) were used as the light source for the green LEDs.

(Cell survival rate by B16 melanoma cells)
B16 melanoma cells were seeded in a 6-well plate at 1×10 ⁴ and 2×10 ⁴ cells/mL, and cultured at 37° C. and 5% CO ₂ for 3 days, after which the medium was replaced with phenol red-free medium. Irradiated with green LED once a day for 3 days, and then cultured for 1 day. Then, Cell Counting Kit-8 (manufactured by Dojindo Chemical Industries, Ltd.) was added and cultured for 3 hours. After culture, the medium was dispensed, the absorbance at 450 nm was measured, and the number of surviving cells was calculated. The higher the absorbance at 450 nm, the higher the number of surviving cells.

(Evaluation of Inhibition of Melanin Production by B16 Melanoma Cells)
B16 melanoma cells were seeded in a 6-well plate at 1×10 ⁴ and 2×10 ⁴ cells/mL, and after 3 days of culture at 37° C. and 5% CO ₂ , the medium was replaced with a phenol red-free medium containing 100 nM of melanin synthesis inducer α-MSH. After 3 days of green LED irradiation once a day and 1 day of culture, the cells were washed with 1 mL of PBS (-), dissolved in 2 mol/L aqueous sodium hydroxide solution containing 10 wt% dimethyl sulfoxide (DMSO), and the amount of melanin produced was measured from the absorbance at 405 nm. Furthermore, the amount of cell-derived protein was measured using RC DCTM protein assay (manufactured by BioRad). Based on the measurement results, the amount of melanin per amount of cell-derived protein was calculated.

(Melanin production suppression effect by green LED light irradiation)
It was confirmed that the number of viable B16 melanoma cells decreased and the amount of melanin production decreased when green LED light with wavelengths of 505 nm and 525 nm was irradiated. This tendency was more pronounced with green LED light with wavelengths of 505 nm. This can be seen from the test results shown in Figures 12A and 12B. Figure 12A shows the number of viable B16 melanoma cells when irradiated with green LED light with a wavelength of 505 nm, and Figure 12B shows the number of viable B16 melanoma cells when irradiated with green LED light with a wavelength of 525 nm. In this test, the concentrations after 30 minutes and 60 minutes were measured when the initial cell concentrations were 1 x 10 ⁴ (Cells/mL) and 2 x 10 ⁴ (Cells/mL).

(Evaluation of inhibition of melanin production by human-derived HMV-II melanoma cells HMV-II)
It has been reported that mouse-derived B16 melanoma cells and human-derived HMV-II melanoma cells have different drug sensitivities to skin whitening agents. In the evaluation of the B16 cells, the melanin production inhibitory effect was more pronounced with 505 nm green LED light, so the wavelength was narrowed down to 505 nm for the HMV-II cells to evaluate their effects.

Unlike B16 cells, the melanin synthesis inducer α-MSH had a low effect on the proliferation of melanoma cells in HMV-II cells, so theophylline, an MSH enhancer, was used as a melanin synthesis inducer to evaluate HMV-II cells.
2 mL of 1×10 ⁴ cells/mL HMV-II cell dispersion was dispensed into a 66-well plate, seeded at 1×10 ⁴ cells/mL, and cultured at 37° C. under 5% CO ₂ for 3 days, after which the medium was replaced with 2 mL of phenol red-free medium containing 25 μL of Theophylline after 40 mM culture. Irradiation with 505 nm LED light was performed once a day for 3 days, and then cultured for 1 day. The cells were dissolved in 2 mol/L aqueous sodium hydroxide solution with 300 μL of 2 M NaOH solution containing 10 wt% dimethyl sulfoxide (DMSO), and the amount of melanin produced was measured from the absorbance at 405 nm. Furthermore, the amount of cell-derived protein was measured using RC DCTM protein assay (manufactured by BioRad). Based on the measurement results, the amount of melanin per amount of cell-derived protein was calculated.

(Survival rate by HMV-II cells)
HMV-II cells were seeded at 1 x 10 ⁴ cells/mL in a 6-well plate, cultured at 37°C, 5% CO ₂ for 3 days, and then replaced with phenol red-free medium. After 3 days of 505 nm LED irradiation once a day, the cells were cultured for 1 day. Then, Cell Counting Kit-8 (Dojindo Chemical Industries, Ltd.) was added and the cells were cultured for 3 hours. After the culture, the medium was dispensed and the absorbance at 450 nm was measured. After the measurement, the survival rate was calculated as a relative value to the absorbance at 450 nm without LED light irradiation.

(Melanin production suppression effect by green LED light irradiation)
It was confirmed that irradiation with 505 nm LED light reduced the survival rate of HMV-II cells and reduced the amount of melanin produced.

In both B16 cells and HMV-II cells, it was verified that green LED light irradiation is effective in suppressing melanin production. This can be seen from other test results shown in Figures 13A to 13D. The other tests shown in Figures 13A to 13D were also conducted in the same manner as the tests described above with reference to Figures 12A and 12B. Note that Figure 13E is a table showing the evaluation results obtained from the test results of Figures 13A to 13D. As can be seen from these, 505 nm has a higher melanin production suppression effect than 525 nm, and it was more pronounced at 20 minutes than at 10 minutes. Furthermore, suppression was seen at 30 and 60 minutes with 505 nm, but no suppression effect was seen at 30 minutes with 525 nm, but suppression was seen at 60 minutes.

In this embodiment, green LED light, particularly at a wavelength of 505 nm, was found to be effective in suppressing the production of melanin, which causes blemishes. This can be seen from the test results shown in Figures 14A to 15B. Figures 14A and 14B show the results of the first and second tests, respectively, and Figures 15A and 15B show the results of the first and second tests, respectively. The other tests shown in Figures 14A to 15B were also conducted in the same manner as the tests described above with reference to Figures 12A and 12B.

Fig. 16 to Fig. 19 show other test results. Fig. 16 is a table showing the relationship between the radiation intensity of green LED light and the effect (the effect of suppressing melanin production), and Fig. 17 to Fig. 19 are graphs showing the relationship between the radiation intensity of green LED light and the effect.

Another test, shown in Figures 16 to 19, was carried out as follows.
B16 melanoma 4A5 was provided by Riken BRC. In the content of this experiment, the word "cells" used hereafter refers to these. The cells and cell culture were performed as described in steps S1 to S3 below, and the following media were used.
Dulbecco's Modified Eagle Medium (DMEM, Cat No. 10566-016, Gibco, USA) containing 10.0% (v/v) Fetal Bovine Serum (FBS, Cat No. SH30071.03, Hyclone (registered trademark), UK) and 1.0% (v/v) antifungal agent (Antibiotic-Antimycotic 100X, Cat No. 15240-062, Invitrogen, USA) was used. DMEM containing 10% FBS was prepared containing 100 nM α-Melanocyte stimulating hormone (α-MSH, Cat No. M4135, Sigma-Aldrich, USA) and 100 μM theophylline (Cat No. T1633, Sigma-Aldrich, USA).
Step S1: Cell culture and subculture Cells were seeded at a density of 3.0×105 cells/dish in a 60 mm dish (Cat No. 353002, Falcon (registered trademark), USA) and cultured in a _CO2 incubator ( _CO2 concentration = 5%, 37°C) for 24 hours.
Step S2: The green LED light irradiation medium was removed, washed with phosphate buffer saline (PBS(-), Cat No. 198601, Nissui, Japan), and then replaced with 8 mL of Hank's balanced salt solution (+) (HBSS(+), Cat No. 084-08965, Wako, Japan), and the irradiation device was applied according to the irradiation conditions. Furthermore, the HBSS(+) was removed, and replaced with 3 mL of test medium, followed by culturing for 72 hours. Regarding the irradiation conditions, the irradiation time was set to 3 minutes.
Step S3: After washing with PBS after culturing, alamarBlue (registered trademark) (Cat No. DAL1100, Invitrogen (registered trademark), USA) was diluted 10-fold with serum-free DMEM, and 2 mL of alamarBlue solution was treated to the cells and cultured at 37 ° C. for 2 hours in a _CO2 incubator. The alamarBlue solution was collected and placed in a 96-well plate (Cat No. 9017, costar, USA), and the absorbance at 570 nm and 600 nm (OD570, OD600) was measured using a microplate reader (SPARK (registered trademark) 10M, TECAN, Switzerland). The alamarBlue solution was used as a blank. The alamarBlue solution was removed from the 60 mm dish, and after washing with PBS (-), 1 mL of 1 M aqueous sodium hydroxide solution containing 10% DMSO was added to solubilize the melanin, and the mixture was incubated at 85 ° C for 10 minutes. 100 μL of the melanin solution was placed in a 96-well plate, and the absorbance at 405 nm (OD405) was measured using a microplate reader. The cell viability of the LED application group was calculated by taking the control OD570-600 as 100%. In addition, the melanin production rate was calculated by taking the control and LED irradiation application group OD405 and the OD570-600 measured with alamarBlue as the melanin production rate per cell. A significant difference test was performed using an unpaired t-test between the control and LED application groups. The significance level for both tests was set to less than 5% on both sides.

As can be seen from Figures 16 to 19, when B16 melanoma cells were irradiated with a green LED (505 nm), the melanin production rate was significantly lower than the control at all outputs, and melanin production was suppressed. When the highest output of 11.5 mW/cm ² was applied among 0.5 mW/cm ² to 11.5 mW/cm ² , the melanin production rate per cell was also significantly lower than the control, and the highest output among these conditions tended to suppress production. From these, as described above, it can be said that the radiation intensity of the specified light from the light irradiation unit 30 is preferably in the range of 0.5 mW/cm ² or more, and more preferably 11.5 mW/cm ² or more.

Also, Fig. 19A shows the difference in effect when irradiating green LED light with a wavelength of 520 nm at different radiation intensities. The test shown in Fig. 19A was also carried out in the same manner as Fig. 8 and the like. In Fig. 19A, the control indicates the test result without any irradiation. Here, the test results of 9 mW/ ^cm2 and 62 W/ ^cm2 are compared with the control. Graphs A, B, and C correspond to cell viability, melanin production rate, and melanin production rate per cell, respectively.

As can be seen from Fig. 19A, when the radiation intensity of the predetermined light from the light irradiation unit 30 becomes higher than a certain level, the effect does not become significantly large (i.e., it becomes saturated). From these, as described above, it can be said that the radiation intensity of the predetermined light from the light irradiation unit 30 is preferably in the range of 0.5 mW/ ^cm2 or more and 62 mW/ ^cm2 or ^less , and more preferably in the range of 11.5 mW/ ^cm2 or more and 62 mW/ ^cm2 or less. Also, from the viewpoint of power consumption, it can be said that an upper limit value of about 30 mW/ ^cm2 is desirable instead of 62 mW/cm2.

In each of the above tests, the irradiation energy of the predetermined light from the light irradiation unit 30 was in the range of 0.09 J/cm ² or more and 11 J/cm ² or less. In addition, taking into account other test results disclosed in this specification, the tests were performed with the irradiation energy of the predetermined light from the light irradiation unit 30 in the range of 0.09 J/cm ² or more and 45 J/cm ² or less. Effective effects were also confirmed even with a relatively small irradiation energy range of 0.09 J/cm ² or more and 11 J/cm ² or less.

The light irradiation device 1 may irradiate the above-mentioned green LED light onto the dry skin of the user, but may also irradiate the green LED light onto skin to which a gel or liquid containing a substance to be permeated has been applied. In this case, the substance to be permeated may be any substance. The substance may be a substance that can be applied to human skin, and typically may be a substance that can be expected to have various effects, such as cosmetic effects.

Next, we will further explain the preferred wavelength range of light to be irradiated onto the skin with reference to Figure 20 onwards.

The test described above with reference to Figures 12A and 12B above showed that irradiation with green LED light of wavelengths of 505 nm and 525 nm reduced the survival rate of B16 melanoma cells and reduced melanin production.

Figure 20 shows other test results, and shows the test results when LED light with wavelengths of 450 nm, 520 nm, and 850 nm was irradiated. Figure 20 shows the test results for cell survival rate, melanin production rate, and melanin production rate per cell when LED37 was irradiated with wavelengths of 450 nm, 520 nm, and 850 nm. In Figure 20, the control shows the test results when nothing was irradiated.

Note that the test results shown in Figure 20 were conducted by a different institution than the tests described above with reference to Figures 12A and 12B, but the test method was substantially the same.

As can be seen from Figure 20, significant inhibition of melanin production was confirmed at wavelengths of 520 nm and 450 nm. In other words, it was shown that the survival number of B16 melanoma cells decreased, and the amount of melanin produced decreased. It was also suggested that the melanin production inhibitory effect may be greater at 520 nm than at 450 nm. Although some tendency for inhibition was observed at a wavelength of 850 nm, there was no significant difference, and it was the lowest result.

Figure 21 shows further test results, and is a diagram showing test results relating to the difference in melanin production suppression effect caused by the difference between three types of wavelengths. Figure 21 shows test results for the melanin production rate per cell when irradiated with LED 37 wavelengths of 505 nm, 525 nm, and 630 nm. Note that in Figure 21, the control also shows the test results when nothing was irradiated.

Note that the test results shown in Figure 21 were conducted by a different institution than the tests described above with reference to Figures 12A and 12B, but the test methods were substantially similar.

As can be seen from Figure 21, no significant inhibition of melanin production was observed at wavelengths of 525 nm or 630 nm, as was observed at a wavelength of 505 nm.

Figure 22 shows further test results, and is a diagram showing test results relating to the difference in melanin production suppression effect caused by the difference between four types of wavelengths. Figure 22 shows test results for cell survival rate when irradiated with LED 37 wavelengths of 470 nm, 490 nm, 505 nm, and 525 nm. Note that in Figure 22, the control also shows the test results when nothing was irradiated.

Note that the test results shown in Figure 22 were conducted by a different institution than the tests described above with reference to Figures 12A and 12B, but the test method was substantially the same.

As can be seen from Figure 22, the survival rate of B16 melanoma cells was lower at wavelengths of 470 nm, 505 nm, and 525 nm compared to the wavelength of 490 nm. In other words, the superiority of wavelengths of 470 nm, 505 nm, and 525 nm over the wavelength of 490 nm (superiority in terms of the effect of inhibiting melanin production) was demonstrated.

Figure 23 shows the test results for the expression level of keratin 10. Figure 23 shows the test results for the expression level of keratin 10 when irradiated with LED 37 at wavelengths of 470 nm, 505 nm, and 590 nm.

The test method is outlined below:

(Step S1) Cell preculture Human epidermal keratinocytes (NHEK) were put to sleep in a T-75 flask using a medium and cultured in a _CO2 incubator (5% _CO2 , 37°C, humidified). When the cells reached about 80% confluence, they were passaged to a T-225 flask, cultured until the required number of cells was obtained, and then used for the subsequent test. The cell passage method is as follows. After washing the cells with PBS (-/-), the cells were detached using 0.05% Trypsin-EDTA, and a trypsin neutralizing solution was added to neutralize the trypsin. Next, the cell suspension was collected in a centrifuge tube and centrifuged (room temperature, 180 xg, 5 min). The supernatant was removed, new medium was added to suspend the cells, and the number of cells was counted. The cells were suspended to the desired cell density using a medium, and seeded in a culture vessel to be used in the test.

(Step S2) Cell treatment The cells were seeded on a 60 mm dish at 900,000 cells/dish/3 mL. The next day after seeding, 5 mL of medium was added, making a total of 8 mL, and device treatment was performed for 30 seconds. Treatment was performed every 24 hours ± 1 hour, and a total of three facial treatments were performed with the facial beauty device. Calcium chloride was added to the medium at the same time as the first device treatment, making the medium 8 mL. Then, treatment was performed for 72 hours.

(Step S3) RNA Extraction RNA was extracted using RNeasy Plus Mini Kit using cells 24 hours after the final instrument treatment. The method was according to the kit's protocol. After RNA extraction, the concentration was measured using NanoDrop Eight and stored at -80°C.

(Step S4) Quantitative PCR
One Step real-time RT-PCR was performed using the QuantiTect Probe RT-PCR Kit included with the FastLane Cell Probe Kit with the composition shown in the table below. The RNA sample was diluted to approximately 100 ng/μL before use. The RT-PCR reaction was performed under the following conditions: 50°C, 30 min-95°C, 15 min-(94°C, 15 sec-60°C, 60 sec) x 40 cycles. The GAPDH gene was used as an internal standard gene.

As can be seen from Figure 23, the expression level of keratin 10 was significantly greater at a wavelength of 505 nm than at wavelengths of 470 nm and 590 nm. In other words, the superiority of the 505 nm wavelength over the 470 nm and 590 nm wavelengths (superiority in terms of the expression effect of keratin 10) was demonstrated.

Here, we explain the mechanism of turnover. The epidermis is arranged in four layers: the basal layer, the spinous layer, the granular layer, and the stratum corneum. At the cellular level, turnover occurs in four stages: cell proliferation in the basal layer, keratin (K10) synthesis in the spinous layer, cell death (apoptosis and necrosis) in the granular layer, and cleavage by a proteolytic enzyme (KLK8) in the stratum corneum. In human skin, the process in which epidermal cells are generated in the basal layer, mature as they migrate toward the upper layers, and are formed by exfoliation at the stratum corneum is called turnover.

If keratin synthesis decreases, the epidermal structure cannot be maintained, resulting in wrinkles and sagging. With rapid turnover, immature epidermal cells are exposed to the outside world before they have become keratinized. Excessive turnover can also lead to the pathology of atopic dermatitis. With slow turnover, keratin that should have peeled off as dandruff remains and thickens. Furthermore, abnormal delays can lead to psoriasis, keratosis, and other conditions. Therefore, indicators other than cell proliferation are also essential factors when considering normal turnover.

In this way, keratin 10 is expressed in the spinous layer and is useful in the turnover process due to the mechanism of turnover. The expression of keratin 10 suggests that normal turnover is proceeding.

Also, there is a paper reporting that blue light irradiation inhibits the TGF-β signaling pathway, thereby inhibiting cell proliferation and collagen expression in human skin fibroblasts (Ge Ge et al., "Induced skin aging by blue-light irradiation in human skin fibroblasts via TGF-β, JNK and EGFR pathways," Journal of Dermatological Science). From this point of view, it is strongly inferred that a wavelength of 505 nm is more advantageous than a wavelength of 470 nm.

The test results shown in Figures 12A, 12B, and 20 to 23 show that irradiating the skin with light having a central wavelength in the wavelength range longer than 490 nm and equal to or less than 525 nm is more advantageous in terms of the effect of suppressing melanin production and the effect of expressing keratin 10 than irradiating the skin with light having a central wavelength in other wavelength ranges.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or some of the components of the above-mentioned embodiments.

For example, in the above embodiment, the light irradiation unit 30 includes an IPL 31 as the first light source and an LED 37 as the second light source, but the mechanisms and mechanisms used as the first light source and the second light source are not limited to an IPL or an LED, and other mechanisms and mechanisms may be used as the first light source and the second light source. For example, a halogen lamp or a laser may be used as the first light source and the second light source.

1. Light irradiation device (skin treatment device)
2 gripping part 3 head part 3a skin facing part 30 light irradiation part 31 IPL (intense pulsed light)
32 First reflector 33 Filter 34 Lower holder 35 Second reflector 36 Upper holder 37 LED (Light Emitting Diode)
38 Holder flange 4 Light guide 41 Light passing portion 411 First emission surface 42 Light guide portion 421 Second emission surface 43 Light shielding portion 44 Contact portion 5 Sensor portion 51 Substrate 52 Light emitting element 53 Light receiving element 54 Opening 8 Control device 81 IPL driving portion 82 LED driving portion 9 Power source

Claims

A first light source that generates light of a predetermined wavelength;
a second light source that generates light having a wavelength different from the predetermined wavelength of the first light source;
a first exit surface through which light from the first light source is emitted;
a second exit surface through which light from the second light source is emitted,
A skin treatment device, wherein a path along which light from the first light source reaches the first exit surface and a path along which light from the second light source reaches the second exit surface do not intersect.
The skin treatment device of claim 1, wherein the second exit surface is inclined relative to the first exit surface.
The skin treatment device according to claim 1, further comprising a light guide having the first exit surface and the second exit surface.
The skin treatment device according to claim 1, wherein the second light source generates light having a central wavelength in the wavelength range of 430 nm or more and 480 nm or less, light having a central wavelength in the wavelength range of 490 nm or more and 525 nm or less, light having a central wavelength in the wavelength range of 530 nm or more and 600 nm or less, light having a central wavelength in the wavelength range of 610 nm or more and 650 nm or less, and light having a central wavelength in the wavelength range of 800 nm or more and 2500 nm or less, or a combination of at least two of these lights.
The skin treatment device of claim 1, wherein the first light source includes an IPL.
The skin treatment device of claim 1, wherein the second light source includes an LED.
A first light source that generates light of a predetermined wavelength;
a second light source that generates light having a wavelength different from the predetermined wavelength of the first light source;
a light guide interposed between the first light source and the second light source and a user's skin;
a sensor unit disposed in the vicinity of the light guide for determining a skin condition of the user;
A skin processing device in which, while at least one of the first light source and the second light source irradiates light, the sensor unit determines the condition of the user's skin, and adjusts the output of at least one of the first light source and the second light source according to the determined skin condition of the user.
The skin treatment device according to claim 7, wherein the sensor unit includes a light-emitting unit that generates test light and a light-receiving unit that receives the test light reflected by the user's skin, and determines the condition of the user's skin based on an electrical output value output from the light-receiving unit according to the amount of light received by the light-receiving unit.
The skin treatment device according to claim 7, wherein the sensor unit includes a light receiving unit that receives light emitted by the second light source and reflected by the skin of the user, and determines the condition of the user's skin based on an electrical output value output from the light receiving unit according to the amount of light received by the light receiving unit.
A gripping portion and an attachment detachable from the gripping portion,
The skin treatment device of claim 3 , wherein the attachment includes at least the light guide of the first light source, the second light source, and the light guide.
A gripping portion and an attachment detachable from the gripping portion,
The skin treatment device according to claim 7 , wherein the attachment includes at least the light guide of the first light source, the second light source, the light guide, and the sensor unit.