CN118902601A - Laser device and method for subcutaneous focusing - Google Patents

Abstract

The invention discloses a laser device and a method for subcutaneous focusing. The laser device comprises a shell, a laser and a focusing lens; wherein, the laser is accommodated in the hollow inner cavity of the shell and used for emitting laser; the focusing lens is used for realizing subcutaneous focusing on the laser so as to form a focusing light spot at a subcutaneous preset position. The energy density of the collimated laser beam is lower than a preset skin damage threshold, the laser which is lower than the skin damage threshold is adopted to irradiate the skin surface, under the condition that the safety of the skin surface is ensured, under the condition that the laser energy density increase amplitude of the focal point beam waist position exceeds the laser energy attenuation amplitude, the effect that the subcutaneous laser energy density of the focal point beam waist position greatly exceeds the skin damage threshold is realized, so that subcutaneous restorability burn is caused, the tissue repair function is stimulated, and the improvement of the skin state is realized.

Description

Laser device and method for subcutaneous focusing

Technical Field

The invention relates to a laser device for subcutaneous focusing and also to a method for achieving subcutaneous focusing by using the laser device, belonging to the technical field of medical devices.

Background Art

The skin tissue of the human body reaches the superficial fascia layer in anatomy, and is generally composed of epidermis, dermis, and subcutaneous tissue from top to bottom, as shown in Figure 1. Among them, the subcutaneous tissue is mainly composed of fat layer. The thickness of the skin varies greatly among different people and different skin parts. The skin thickness in the general sense is about 0.4 to 4 mm (excluding subcutaneous tissue).

Energy-based treatments for the skin generally include laser, intense pulsed light, radio frequency, microneedle radio frequency, focused ultrasound and other technical means. The purpose of medical cosmetology for the skin includes removing spots and tattoos, improving pigmentation, peeling and rejuvenating, hair removal, removing wrinkles, stimulating collagen regeneration, stimulating and lifting the fascia layer to improve tissue sagging, fat ablation, slimming and weight loss, etc. For medical cosmetology for the skin, different technical means need to be used for different treatment depths. For operations such as removing spots and tattoos, improving pigmentation, peeling and rejuvenating at the epidermal position, due to the shallow depth of action, it is generally effective to use laser and intense pulsed laser for surface irradiation. Since collagen is located in the deeper dermis, for operations such as removing wrinkles and stimulating collagen regeneration, radio frequency or microneedle radio frequency with an invasion depth of 0.5 to 5 mm is generally used to achieve a greater heating depth. For deeper fat layer ablation, fascia layer lifting and improvement, subcutaneous puncture laser lipolysis liposuction, focused ultrasound and other methods are preferred.

However, due to the different optical characteristics of laser reflection, absorption, heat dissipation, etc. in skin tissue, the laser incident on the skin surface will rapidly attenuate as the depth increases. Therefore, most wavelengths of lasers are difficult to use for treating deep skin tissue. Traditional laser treatment plans for skin surgery generally involve: large-area surface irradiation or laser scanning focusing or microlens focusing, and then acting on the skin surface for energy-based treatment. These laser treatment plans cannot significantly increase the energy density under the skin while ensuring the safety of the skin surface, and therefore cannot meet the requirements for energy-based treatment at deeper locations under the skin.

Summary of the invention

The primary technical problem to be solved by the present invention is to provide a laser device for subcutaneous focusing.

Another technical problem to be solved by the present invention is to provide a method for achieving subcutaneous focusing using the laser device.

In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

According to a first aspect of an embodiment of the present invention, there is provided a laser device for subcutaneous focusing, comprising:

A housing having a hollow inner cavity and a bottom opening communicating with the hollow inner cavity;

A laser, contained in the hollow inner cavity, for emitting laser light with a wavelength of 900 to 1300 nm toward the bottom opening;

A focusing lens, which is blocked at the bottom opening and located at a side of the collimator away from the laser, and is used to achieve subcutaneous focusing of the laser, thereby forming a focused light spot of a preset size at a preset position under the skin;

Among them, the subcutaneous preset position is located in the dermis, fat layer or skin fascia layer and below below the skin surface, and the subcutaneous preset position is the focal waist position of the focusing lens; and the laser energy density emitted by the laser is lower than a preset skin damage threshold on the skin surface and exceeds the skin damage threshold at the focal waist position.

Preferably, the skin damage threshold is determined by skin color, and the whiter the skin color, the higher the skin damage threshold.

Preferably, the focal point of the focusing lens is 0.5 to 8 mm away from the skin surface, the diameter of the focusing lens is greater than 2 mm, and the convex side of the focusing lens faces the laser.

Preferably, the focusing lens cooperates with an optical coupling liquid located between the plane of the focusing lens and the skin, so that the focused light spot is in a shallow area 0.5 to 8 mm below the skin, and the tissue at the waist position is heated to 45 to 85°C, causing subcutaneous reversible burns; wherein the optical coupling liquid has a similar refractive index to the skin.

Preferably, the focusing lens comprises a plurality of fly-eye lenses, and the plurality of fly-eye lenses are arranged together to form a fly-eye lens array of a preset shape;

Each of the fly-eye lenses forms a sub-spot at the preset position, each sub-spot corresponds to a focus, the sub-spots formed by all fly-eye lenses together constitute the focused spot, and the distance between two adjacent focuses is equal to the period of the fly-eye lens.

Preferably, the laser device further comprises:

The translation mechanism is connected to the shell and drives the shell to translate along a preset direction.

Preferably, the preset shape is a regular hexagon, the preset direction is the direction of the edges of the regular hexagon, and the distance of each translation of the shell is half the distance between two adjacent foci, so that the focal density of the focused light spot is doubled.

Preferably, the laser device further comprises:

The cooling part is arranged on the housing and close to the skin, and is used for cooling the contact area between the skin and the focusing lens.

Preferably, the focusing lens is a single lens or a Fresnel lens.

Preferably, the laser beam incident on the focusing lens is a parallel laser beam, a converging laser beam or a diverging laser beam; wherein,

The parallel laser beam is directly formed by a solid laser after optical beam expansion/contraction and optical homogenization;

The converged laser beam is composed of laser beams emitted by multiple laser emission points and incident on the focusing lens together; and the depth of the subcutaneous preset position corresponding to the converged laser beam is less than the depth of the subcutaneous preset position corresponding to the parallel beam;

The divergent laser beams are scattered laser beams emitted by a laser emitting point and are incident on the focusing lens together; and the depth of the subcutaneous preset position corresponding to the divergent laser beam is greater than the depth of the subcutaneous preset position corresponding to the parallel beam.

Preferably, the beam power or energy of the parallel laser beam is distributed in a flat-top manner.

Preferably, an optical glass with a refractive index close to that of the skin is inserted between the focusing lens and the skin, which is used to adjust the distance between the focusing lens and the skin, adjust the subcutaneous depth of the focus of the focusing lens, or for heat dissipation and cooling conducted on the skin surface; wherein the optical glass cooperates with the focusing lens to form a complete lens assembly.

Preferably, a preset gap is formed between the focusing lens and the skin, so that the laser beam focused by the focusing lens forms a surface spot on the skin surface, and after refracting into the subcutaneous tissue, forms a focusing spot at a preset position under the skin, thereby achieving non-contact focusing of the laser beam.

Preferably, a 45-degree reflector and a coaxial thermal imager are installed at the output end of the focusing lens; or a paraxial thermal imager is installed at the output end of the focusing lens;

The 45-degree reflector is made of infrared optical material with good transmittance in the thermal imaging band of the sensor, and the surface is coated with a high-reflection film for reflecting the incident laser.

According to a second aspect of an embodiment of the present invention, a method for achieving subcutaneous focusing is provided, comprising the following steps:

The laser device is placed above the skin, and the focusing lens of the laser device is attached to the skin surface;

The laser is controlled to emit a laser beam with a wavelength of 900 to 1300 nm toward the skin, so that the laser beam is collimated by the collimator and then emitted to the focusing lens, and forms a focusing spot of a preset size at a preset position under the skin through the focusing lens.

Preferably, the method further comprises:

The housing is controlled to translate as a whole along the skin surface to increase the size of the focused light spot and the focal density of the focused light spot.

Preferably, the focusing lens includes a plurality of fly-eye lenses, and the plurality of fly-eye lenses are arranged together into a regular hexagonal fly-eye lens array to form a regular hexagonal focusing spot at the preset position under the skin; wherein the four consecutive vertices of the regular hexagonal spot are defined as A, B, C, and D; and the position of vertex A when the focusing spot does not move is position 1, the position of vertex B after the focusing spot moves for the first time is position 2, the position of vertex C after the focusing spot moves for the second time is position 3, and the position of vertex D after the focusing spot moves for the fourth time is position 4;

The shell is driven by a translation mechanism to translate in the directions of A-1, B-2, C-3, and D-4 in sequence, and the distance of each translation is half of the aperture of the compound eye lens, thereby increasing the size of the treatment area and doubling the focal density of the focused light spot.

Compared with the prior art, the present invention has the following technical effects:

1. Through research, it is found that there is a spectral region with relatively small optical loss in the spectral position of skin tissue at around 900-1300nm. Lasers in this band can achieve deeper skin penetration depth. On this basis, the present invention uses lasers with relatively low skin loss in the 900-1300nm band, and focuses the laser subcutaneously. While not increasing the energy density on the skin surface and ensuring the safety of the skin surface, the laser energy density of the skin tissue at the subcutaneous focusing position is effectively increased, so as to achieve effective treatment of deep skin tissue.

2. The focusing lens uses a large-aperture, short-focal-length lens and is close to the skin. Therefore, it not only reduces the energy density on the skin surface to improve the safety of treatment on the skin surface, but also increases the energy density at the preset position under the skin to improve the effectiveness of treatment of deep skin tissue. The lens and the skin are coupled through a refractive index-matched liquid to reduce interface loss during large-angle focusing.

3. The focused light spot can be translated by mechanical translation, manual movement, etc., so that the laser focus density in the area to be treated is significantly increased, thereby achieving two-dimensional coverage treatment along the skin surface.

4. The laser beam emitted by the laser is collimated by the lens and then focused by the compound eye lens array, thereby achieving a uniform dot matrix focusing effect.

5. The calculation of the subcutaneous focal position takes into account the influence of the skin refractive index. According to different skin colors, the general skin refractive index is about 1.3 to 1.6, thereby improving the calculation accuracy of the subcutaneous focal position. A specific optical instrument can be designed to measure the refractive index through a skin pinch test or earlobe before treatment, so as to calculate the lens focal depth and select the lens. The refractive index measuring instrument can work independently but in coordination with the laser device, or it can be designed as a part of the laser device.

6. The focusing lens can be a single convex lens, a Fresnel lens, a compound eye lens array, a cylindrical lens array, etc., to meet the treatment needs of different scenarios.

7. The laser can output a parallel beam with a flat-top distribution, thereby improving the uniformity of energy distribution at the subcutaneous focal position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the depth of action of existing human skin tissue and commonly used optoelectronic devices;

FIG2 is a schematic diagram of optical loss of various laser light sources in different wavelength bands to achieve subcutaneous focusing;

FIG3 is a schematic structural diagram of a laser device for subcutaneous focusing provided by the first embodiment of the present invention;

FIG4A is a schematic diagram of a focusing spot formed by a fly-eye lens array in the first embodiment of the present invention;

4B is a schematic diagram of the structure of a thermal imager with a 45-degree reflector and coaxial observation installed at the position of the collimated laser beam in the second embodiment of the present invention;

FIG4C is a schematic diagram of a structure in which an optical glass is inserted between the focusing lens and the skin in the second embodiment of the present invention;

FIG4D is a schematic diagram of a structure in which a preset gap is formed between the focusing lens and the skin in the second embodiment of the present invention;

FIG5 is a schematic structural diagram of a laser device for subcutaneous focusing provided by a second embodiment of the present invention;

FIG6 is a schematic diagram of the hexagonal fly-eye lens array before and after movement;

FIG7 is a schematic diagram of a structure for achieving subcutaneous focusing by irradiating a convergent laser beam provided in a fourth embodiment of the present invention;

FIG8 is a schematic diagram of a structure for achieving subcutaneous focusing by irradiating a divergent laser beam provided in a fourth embodiment of the present invention;

FIG9 is a schematic diagram of a structure for achieving subcutaneous focusing by using parallel laser beam irradiation provided by a fourth embodiment of the present invention;

FIG10 is a schematic structural diagram of a laser device for subcutaneous focusing provided by a fifth embodiment of the present invention;

FIG. 11 is a flow chart of a method for achieving subcutaneous focusing according to the sixth embodiment of the present invention.

DETAILED DESCRIPTION

The technical content of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

Considering the absorption and scattering losses of different substances in the skin and subcutaneous tissue, including water, melanin, hemoglobin (deoxygenated and oxygenated hemoglobin), protein (such as collagen in the dermis), fat, etc., as shown in FIG2, the inventors studied the optical loss of various laser light sources in different bands to achieve subcutaneous focusing, and observed that there is a spectral region with relatively small optical loss in the spectral position of skin tissue around 900 to 1300nm (i.e., the region shown in the dotted box in FIG2). In this band of laser, the absorption coefficient of spectral energy of substances such as water, melanin, hemoglobin, collagen, etc. in skin tissue is relatively small, that is: the optical loss of laser in this band is the lowest, so that a deeper skin penetration depth can be achieved. Therefore, the embodiment of the present invention provides a laser device and method for subcutaneous focusing, which can achieve low laser power density on the skin surface (to ensure the safety of treatment) but high laser power density deep in the skin tissue (to ensure the effectiveness of treatment) under the condition of low optical loss, thereby forming an effective energy-based treatment method.

Based on this, the embodiment of the present invention provides a laser device and method for subcutaneous focusing, which uses a laser with relatively low skin loss in the 900-1300nm band, and achieves subcutaneous focusing of the laser. While not increasing the energy density on the skin surface and ensuring the safety of the skin surface, the laser energy density of the skin tissue at the subcutaneous focusing position is effectively increased to achieve effective treatment of deep skin tissue. The present invention is particularly suitable for laser treatments such as stimulating the growth of collagen in the subcutaneous dermis, laser heating apoptosis or ablation of subcutaneous fat, and heating stimulation and lifting of the skin fascia layer.

First embodiment

As shown in Fig. 3, a laser device for subcutaneous focusing provided by the first embodiment of the present invention includes a laser 1, a collimator 2, a focusing lens 3 and a housing 4. The laser 1 is used to emit a laser with a wavelength of 900 to 1300 nm, more preferably a laser with a wavelength of 924 nm for fat ablation; the collimator 2 is used to collimate the laser to form a collimated laser; the focusing lens 3 is used to focus the collimated laser subcutaneously to form a focused light spot; the housing 4 serves as the installation base for the laser 1, the collimator 2 and the focusing lens 3, and provides safety protection for the internal components.

Specifically, in this embodiment, as shown in FIG. 3 , the housing 4 has a hollow inner cavity 401 and a bottom opening 402 communicating with the hollow inner cavity 401. Accordingly, the laser 1 and the collimator 2 are both disposed in the hollow inner cavity 401, and the focusing lens 3 is blocked at the bottom opening 402. Thus, the housing 4 is used as an installation base, so that the laser 1, the collimator 2, and the focusing lens 3 are installed together in the housing 4.

In this embodiment, the laser 1 is arranged above the skin 10, and is used to emit a laser with a wavelength of 900 to 1300 nm toward the skin 10, and the beam of the laser 1 is flat-topped. It should be noted that the inventors have found through their research that there is a spectral region with relatively small optical loss at the spectral position of 900 to 1300 nm. Therefore, by selecting a laser 1 with a specific wavelength, a deeper skin penetration depth (for example, 3 to 5 mm) can be achieved to achieve laser treatment deep in the skin. In this spectral region, the absorption coefficient of oxygenated hemoglobin is about 0.2 to 0.4/cm; the absorption coefficient of deoxyhemoglobin is about 0.7 to 0.85/cm, the absorption coefficient of melanin is about 4 to 7/cm, and the absorption coefficient of water is about 0.16 to 0.2/cm.

Moreover, in this embodiment, the energy density of the collimated beam of the laser 1 is lower than the preset skin damage threshold (in J/cm ² ). The skin damage threshold is generally determined by the skin color, and the whiter the skin color, the higher the skin damage threshold. According to the treatment experience of dermatological surgery, according to different skin colors: the skin damage threshold of type I skin color is about 20J/cm ² ; the skin damage threshold of type II-III skin color is about 10J/cm ² ; the skin damage threshold of type IV-V-VI skin color is about 5J/cm ² , so as to avoid burning the skin surface. Therefore, by using a laser lower than the skin damage threshold to irradiate the skin surface, while ensuring the safety of the skin surface, through further optical focusing, when the increase amplitude of the laser energy density at the focal beam waist position exceeds the laser energy attenuation amplitude, the laser energy density at the focal beam waist position under the skin is greatly exceeded the skin damage threshold, thereby causing subcutaneous recoverable burns.

In addition, preferably, the laser 1 uses a 1064nm Nd:YAG laser or a 900-1300nm semiconductor laser. It is understandable that the wavelength of the semiconductor laser can be designed and customized as needed (achieved through epitaxial design and growth of semiconductor materials). In another preferred embodiment, a semiconductor laser with fiber-coupled output (the wavelength can be customized at will, and the electro-optical conversion efficiency reaches more than 50%) is selected, which has a longer optical life than Nd:YAG and a lower cost.

In addition, in the above embodiment, preferably, the output of the laser 1 is required to be a flat-top laser beam, so as to improve the uniformity of energy distribution at the subcutaneous focal position.

As shown in FIG3 , in this embodiment, the collimator 2 is arranged on the light-emitting side of the laser 1 to collimate the laser, thereby forming a collimated laser. Specifically, in this embodiment, the collimator 2 is a collimating lens, which forms a cylindrical parallel laser beam after collimating the laser, and then projects it to the focusing lens 3 to achieve subcutaneous focusing. It can be understood that setting the collimator 2 as a collimating lens is only one of the preferred implementations. In other embodiments, other forms of collimating structures can be selected as needed.

The focusing lens 3 is arranged on the side of the collimator 2 away from the laser 1 and is attached to the surface of the skin 10, and is used to achieve subcutaneous focusing of the collimated laser, thereby forming a focused light spot 20 of a preset size at a preset subcutaneous position O (beam waist).

Generally, lasers are Gaussian beams. At different focusing angles, the characteristics of Gaussian beams are: beam parameter product = beam waist * far-field divergence angle is a constant value. It can be roughly considered that its far-field divergence angle is approximately its focusing angle. Therefore, the larger the focusing angle, the shorter the focal length, and the smaller the beam waist near the focus; conversely, the smaller the focusing angle, the longer the focal length, and the larger the beam waist near the focus.

It is understandable that in this embodiment, preferably, the focusing lens 3 is designed with a large aperture and a small focal length, and a liquid with a refractive index matching the skin and the focusing lens is used for optical path matching. It is understandable that the larger the numerical aperture (Numerical Aperture) of the optical system formed by the focusing lens, the better, and the numerical aperture value is increased by controlling the focal length of the focusing lens 3 to become shorter and the aperture to become larger. Specifically, in this embodiment, the focal point of the focusing lens is 0.5 to 8 mm from the skin surface, and the diameter of the focusing lens is greater than 2 mm. In addition, the convex side of the focusing lens 3 faces the laser 1, and the flat side of the focusing lens 3 is pressed against the skin. In addition, by filling an optical coupling liquid (such as olive oil and other liquids with high optical transmittance and friendly to human skin) with a refractive index close to that of the skin (generally 1.3 to 1.6) between the plane of the focusing lens 3 and the skin, a larger optical entrance port, a shorter focusing focal length (i.e., a shallower subcutaneous focal depth), and a smaller focusing spot (i.e., the waist area after focusing) can be achieved to achieve focusing with a large numerical aperture, so that the energy density on the skin surface is low and the energy density under the skin is high. Thus, in the shallower skin layer (0.5 to 8 mm skin and subcutaneous tissue area), the tissue at the waist position is heated to 45 to 85° C. by the focusing spot. At this temperature, the skin tissue components will undergo burn changes such as contraction, coagulation, and denaturation, thereby stimulating the tissue's own repair mechanism and improving the skin properties. As a result, both the low temperature (low energy density) of the surface layer and the high temperature (high energy density) of the waist position are achieved, thereby achieving a recoverable burn at the waist position without losing the skin surface.

In addition, it can be understood that in this embodiment, based on the power, emission wavelength and flat-top distribution of the laser 1, it is matched with the subcutaneous focus position (waist), so as to ensure both the depth of subcutaneous focus and the energy intensity at the waist position. Moreover, in this embodiment, the calculation of the subcutaneous focus position also takes into account the influence of the skin refractive index. According to different skin colors, the general skin refractive index is about 1.3 to 1.6, thereby improving the calculation accuracy of the subcutaneous focus position. On this basis, an additional skin refractive index measuring instrument can be provided. When it is necessary to calculate the subcutaneous focus position, the patient is subjected to a skin pinch test or a refractive index test using the earlobe skin to calculate and match the focus depth of the focusing lens 3.

In the above embodiment, preferably, the laser beam incident on the focusing lens is a parallel laser beam with a flat-top distribution of power or energy. The parallel laser beam with a flat-top distribution can be directly formed by a solid laser after optical beam expansion/contraction and optical homogenization. It can also be formed by a laser transmitted by an optical fiber in combination with a collimator. It can also be formed by arranging and transforming other types of laser light sources.

Specifically, the laser 1 and the collimator 2 can constitute a parallel laser light source with a flat-top distribution, which is used to generate a parallel light beam, thereby improving the uniformity of energy distribution at the subcutaneous focal position. For certain types of lasers, such as Nd:YAG solid lasers with better beam quality, a parallel laser beam with a flat-top distribution can be obtained without collimation, so the collimator 2 is not necessary. Since there is an adjustment of the diameter of the parallel light beam, a beam expander or a beam reducer can be used to adjust the thickness of the parallel light beam. It can be understood that the parallel laser light source in this embodiment can be composed of a laser + collimator output by an optical fiber, or it can be directly provided by a laser. The core requirement is that the parallel laser light source must be a uniform flat-top distribution. Among them, fiber-coupled semiconductor lasers + collimators are more common, with the most flexible wavelength selection and the lowest cost.

Second embodiment

On the basis of the first embodiment, the focusing lens 3 in this embodiment has a fly-eye lens structure.

As shown in FIG3 , in this embodiment, the focusing lens 3 is disposed on a side of the collimator 2 away from the laser 1 and attached to the surface of the skin 10, and is used to focus the collimated laser subcutaneously, thereby forming a focusing spot 20 of a preset size at a preset subcutaneous position O. Specifically, in this embodiment, the focusing lens 3 includes a plurality of fly-eye lenses 31, and the plurality of fly-eye lenses 31 are arranged together to form a hexagonal fly-eye lens array, and the hexagonal fly-eye lens array can be arranged in array forms such as 2-3-2, 3-4-5-4-3, 4-5-6-7-6-5-4, etc. Different array forms correspond to different numbers of fly-eye lenses 31, and specific adaptive selection can be performed according to needs. As shown in FIG4A , each fly-eye lens 31 forms a sub-spot 30 at a preset position O, each sub-spot corresponds to a focus 32 (i.e., a black dot at the center of each spot 30), and the sub-spots formed by all fly-eye lenses together constitute a focused spot 20, and the distance between two adjacent foci is equal to the focus distribution period of the fly-eye lens 31.

In this embodiment, the subcutaneous preset position O includes at least the dermis, the skin fat layer, the skin fascia layer, etc., so as to be suitable for laser treatment methods such as heating the dermis and stimulating collagen growth, laser heating apoptosis or ablation of subcutaneous fat, and tightening and lifting of the skin fascia layer. In various embodiments of the present invention, based on the Fitzpatrick skin color classification rule, skin color categories I-II-III belong to light skin color, and categories IV-V-VI belong to dark skin color. Since the absorption coefficient of melanin is higher at shorter wavelengths and lower at longer wavelengths, 910-930nm is a better fat ablation laser wavelength for light skin or thin skin thickness; for dark skin or thick skin thickness, 1000-1100nm (especially 1060nm or 1064nm) is a laser wavelength that has been verified in practice and effectively transmits to the fat layer and produces ablation. In this way, the heating and ablation effect of the fat layer can be improved. It can be understood that in this embodiment, the focusing lens 3 adopts a large-aperture, short-focal-length lens and is close to the skin. Therefore, it not only reduces the energy density on the skin surface to improve the safety of treatment on the skin surface, but also increases the energy density at the preset subcutaneous position O to improve the effectiveness of treatment of deep skin tissue.

The following is a detailed description of the treatment using the above laser device and a laser beam with a wavelength of 924nm (the best wavelength for fat absorption):

It is known that the average absorption coefficient of the skin near 924nm is about /1cm. Considering that it acts on a position 4mm below the skin (ie: subcutaneous preset position O), the light intensity at this position after attenuation = EXP (-1*0.4) = 67%.

If a 5mm circular spot is used on the body surface, at a distance of 4mm from the subcutaneous part, assuming that the preset size of the focused spot is 1mm in diameter, and using a single-pulse laser energy density of 10J/ ^cm2 that is bearable by the general human body (type I-III skin color) and not prone to burns, then the body surface energy = 3.14*0.25*0.25*10 = 1.96J, and the energy at the subcutaneous focal position (beam waist position) = 1.96*67% = 1.31J. Therefore, the energy density at the focal position reaches 1.31/(3.14*0.05*0.05) = 167J/ ^cm2 .

By comparing the data, it can be seen that the laser device provided by the first embodiment of the present invention can achieve the following technical effects: the laser energy density on the skin surface is low (10J/ ^cm2 ), but the laser energy density at the subcutaneous focus is more than 16 times (167/10=16.7 times) the energy density on the skin surface. It should be noted that this energy density is sufficient to burn any subcutaneous tissue while protecting the surface skin.

In a preferred embodiment of the present invention, as shown in FIG4B , a 45-degree reflector 310 and a coaxial thermal imager 320 can be installed at the output end of the focusing lens 3 to achieve dynamic monitoring of tissue heating temperature and ensure the safety and effectiveness of laser treatment. More preferably, the 45-degree reflector 310 is required to be a material with a friendly transmittance of 8 to 14 um (thermal imaging capture band) such as ZnS or BaF2, and the surface is coated with a high-reflective film for the incident laser to reduce the transmission of the laser and allow more laser beams to be directed to the skin surface.

Preferably, in addition to hard lenses, the lens array can also select flexible optical materials with a refractive index close to that of the skin, and perform skin-fitting treatment through optical coupling agent 330. The flexible lens can be used as a disposable treatment consumable to avoid cross infection caused by contact with the skin of different patients.

In another preferred embodiment, as shown in FIG4C , an optical glass 340 having a refractive index close to that of the skin is inserted between the focusing lens 3 and the skin. It can be understood that, compared with FIG4B , the insertion of optical glass 340 of different thicknesses can be used to adjust the distance between the focusing lens 3 and the skin or adjust the subcutaneous depth of the focus of the focusing lens 3. In addition, since the optical glass 340 has good thermal conductivity, the optical glass 340 can be brought into contact with the skin surface to conduct heat from the skin surface to achieve the purpose of cooling the skin. In this embodiment, the optical glass 340 can be used together with the focusing lens 3 as a complete lens assembly.

In another preferred embodiment, as shown in FIG4D , a preset gap is formed between the focusing lens 3 and the skin, and the specific value of the distance d of the preset gap can be set as needed. Thus, when the incident light is irradiated to the focusing lens 3, the focused laser beam will propagate in the air and irradiate the skin surface to form a surface spot 350. In addition, the laser beam will continue to refract into the subcutaneous tissue to form a focused spot at a preset position under the skin, thereby achieving non-contact focusing of the laser beam. It can be understood that since no optical material is provided in this embodiment, the light beam will be refracted after being irradiated on the skin, thereby affecting the subcutaneous focusing depth. In specific applications, the distance d needs to be adaptively adjusted according to the refraction of the skin.

Third embodiment

On the basis of the above-mentioned first embodiment, the third embodiment of the present invention further provides a laser device for subcutaneous focusing, comprising a laser 1, a collimator 2 and a focusing lens 3. Compared with the first embodiment, the difference of this embodiment is that the focusing spot can be translated, thereby increasing the focus density.

Specifically, in this embodiment, as shown in FIG. 5 , the laser device further includes a translation mechanism 5. The translation mechanism 5 is connected to the housing 4, and drives the housing 4 to translate along any side of the hexagonal fly-eye lens array to increase the size of the focused light spot and the focal density of the focused light spot. Specifically, as shown in FIG. 6 , the housing 4 is translated in the directions of A-1, B-2, C-3, and D-4 in sequence by the translation mechanism 5, and the distance of each translation is half of the period of the fly-eye lens 31, so that after three translations, the focal density of the focused treatment area is significantly increased, thereby achieving two-dimensional coverage treatment along the skin surface.

In the above embodiment, preferably, the laser device further includes a cooling unit. The cooling unit is disposed on the housing 4 and close to the skin, and is used to cool the contact area between the skin and the focusing lens 3. The cooling unit may use a fan to cool the skin by air cooling; or may use a method of contacting the skin for cooling, for example, cooling the skin by contacting sapphire with the skin. It is understood that the specific structural form of the cooling unit may be adaptively selected according to needs, and is not specifically limited here.

Except for the above differences, the rest of the structure of this embodiment is the same as that of the first embodiment and will not be described again.

Fourth embodiment

Based on the above first embodiment, the fourth embodiment of the present invention further provides a laser device for subcutaneous focusing, comprising a laser 1, a focusing lens 3 and a housing 4. The difference between this embodiment and the first embodiment is that the laser beam emitted by the laser 1 is not a parallel beam.

Specifically, as shown in FIG7 , in this embodiment, the laser beam incident on the focusing lens by the laser 1 is a converged laser beam, and the converged laser beam is formed by laser beams emitted from multiple laser emission points being incident on the focusing lens 3. Similarly, in another embodiment, as shown in FIG8 , the laser beam incident on the focusing lens by the laser 1 is a divergent laser beam, and the divergent laser beam is formed by dispersed laser beams emitted from one laser emission point being incident on the focusing lens 3.

From FIG. 7 and FIG. 8 , it can be seen that, due to the different incident angles of the incident laser, when the incident laser is irradiated onto the focusing lens 3, the angles of refraction into the focusing lens 3 are also different, so that the depth of the subcutaneous preset position corresponding to the converged laser beam is smaller than the depth of the subcutaneous preset position corresponding to the divergent laser beam.

As can be further seen from Fig. 9, when the incident laser is a parallel beam, the depth of the subcutaneous preset position corresponding to the parallel laser beam is between the above two. Therefore, the installation position of the focal length of the laser can be adjusted as needed, so as to switch between three different incident modes to achieve treatment of different skin layers.

Except for the above differences, the rest of the structure of this embodiment is the same as that of the first embodiment and will not be described again.

Fifth embodiment

The fifth embodiment of the present invention further provides a laser device for subcutaneous focusing, comprising a laser 1, a collimator 2 and a focusing lens 3. Compared with the first embodiment, the difference of this embodiment is that the focusing lens 3 is a single lens or a Fresnel lens.

As shown in FIG. 10 , it can be understood that the focusing lens 3 formed by a single lens or a Fresnel lens can only focus to form a light spot under the skin.

Except for the above differences, the rest of the structure of this embodiment is the same as that of the first embodiment and will not be described again.

Sixth embodiment

As shown in FIG. 11 , based on the third embodiment described above, the sixth embodiment of the present invention provides a method for achieving subcutaneous focusing, which specifically includes steps S1 to S3:

S1: The laser device is placed above the skin, and the focusing lens 3 of the laser device is placed in contact with the skin surface.

S2: Control the laser 1 to emit a laser beam with a wavelength of 900 to 1300 nm toward the skin, so that the laser beam is collimated by the collimator and then emitted to the focusing lens 3, and forms a focusing spot of a preset size at a preset position under the skin through the focusing lens 3.

S3: Control the housing 4 to translate as a whole along the skin surface to increase the size of the focused light spot and the focal density of the focused light spot.

Specifically, as shown in Fig. 6, the control translation mechanism 5 drives the housing 4 to translate in the directions of A-1, B-2, C-3, and D-4 in sequence, and the distance of each translation is half of the period of the fly-eye lens 31. Therefore, after three translations, the focus density of the focused treatment area is significantly increased, thereby achieving two-dimensional coverage treatment along the skin surface.

It can be understood that the overall translation mode of the laser 1, collimator 2 and focusing lens 3 in this embodiment is mechanical translation, that is, the housing 4 is translated by the translation mechanism 5. In other embodiments, other translation modes may also be used, such as manual movement.

In summary, the laser device and method for subcutaneous focusing provided by the embodiments of the present invention have the following beneficial effects:

1. Through research, it is found that there is a spectral region with relatively small optical loss in the spectral position of skin tissue at around 900-1300nm. Lasers in this band can achieve deeper skin penetration depth. On this basis, the present invention uses lasers with relatively low skin loss in the 900-1300nm band. By focusing the laser subcutaneously, the laser energy density of the skin tissue at the subcutaneous focusing position is effectively improved without increasing the energy density on the skin surface and ensuring the safety of the skin surface, so as to achieve effective treatment of deep skin tissue (which can reach the fascia layer).

2. The focusing lens 3 uses a large-aperture, short-focal-length lens and is close to the skin. Therefore, it not only reduces the energy density on the skin surface to improve the safety of treatment on the skin surface, but also increases the energy density at the preset position under the skin to improve the effectiveness of treatment of deep skin tissue.

3. The focused light spot can be translated by mechanical translation, manual movement, etc., so that the coverage area of the focused light spot is expanded and the focus density of the focused treatment area is significantly increased, thereby achieving two-dimensional coverage treatment along the skin surface.

4. The laser beam emitted by laser 1 is collimated by a lens and then focused by a compound eye lens array, thereby improving the focusing effect.

5. The calculation of the subcutaneous focus position takes into account the influence of the skin refractive index. According to different skin colors, the general skin refractive index is around 1.3 to 1.6, which improves the calculation accuracy of the subcutaneous focus position.

6. The focusing lens 3 can be a single convex lens, a Fresnel lens or a compound eye lens array to meet the treatment needs of different scenarios.

7. After being collimated by the collimator 2, the laser 1 can form a parallel beam with a flat-top distribution, thereby improving the uniformity of energy distribution at the subcutaneous focusing position.

It should be noted that the above-mentioned multiple embodiments are only examples, and the technical solutions of various embodiments can be combined, all of which are within the protection scope of the present invention.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

The above is a detailed description of the laser device and method for subcutaneous focusing provided by the present invention. For those skilled in the art, any obvious changes made to it without departing from the essence of the present invention will constitute an infringement of the patent right of the present invention and will bear corresponding legal responsibilities.

Claims (16)

1. A laser device for subcutaneous focusing, characterized by comprising: A housing having a hollow inner cavity and a bottom opening communicating with the hollow inner cavity; A laser, contained in the hollow inner cavity, for emitting laser light with a wavelength of 900 to 1300 nm toward the bottom opening; A focusing lens, which is blocked at the bottom opening and located at a side of the collimator away from the laser, and is used to achieve subcutaneous focusing of the laser, thereby forming a focused light spot of a preset size at a preset position under the skin; Among them, the subcutaneous preset position is located in the dermis, fat layer or skin fascia layer and below below the skin surface, and the subcutaneous preset position is the focal waist position of the focusing lens; and the laser energy density emitted by the laser is lower than a preset skin damage threshold on the skin surface and exceeds the skin damage threshold at the focal waist position; the skin damage threshold is determined by the skin color. 2. The laser device according to claim 1, characterized in that: The focal point of the focusing lens is 0.5 to 8 mm away from the skin surface, and the diameter of the focusing lens is greater than 2 mm. The convex side of the focusing lens faces the laser. 3. The laser device according to claim 2, characterized in that: The focusing lens cooperates with the optical coupling liquid located between the plane of the focusing lens and the skin, so that the focused light spot is in a shallow area 0.5 to 8 mm below the skin, and the tissue at the waist position is heated to 45 to 85° C., causing subcutaneous reversible burns; wherein the refractive index of the optical coupling liquid is similar to that of the skin. 4. The laser device according to any one of claims 1 to 3, characterized in that: The focusing lens comprises a plurality of fly-eye lenses, and the plurality of fly-eye lenses are arranged together to form a fly-eye lens array of a preset shape; Each of the fly-eye lenses forms a sub-spot at the preset position, each sub-spot corresponds to a focus, the sub-spots formed by all fly-eye lenses together constitute the focused spot, and the distance between two adjacent focuses is equal to the period of the fly-eye lens. 5. The laser device according to claim 4, further comprising: The translation mechanism is connected to the shell and drives the shell to translate along a preset direction. 6. The laser device according to claim 5, characterized in that: The preset shape is a regular hexagon, the preset direction is the direction of the edges of the regular hexagon, and the distance of each translation of the housing is half the distance between two adjacent foci, so that the focal density of the focused light spot is doubled. 7. The laser device according to claim 4, further comprising: The cooling part is arranged on the housing and close to the skin, and is used for cooling the contact area between the skin and the focusing lens. 8. The laser device according to claim 6, characterized in that: The focusing lens is a single lens or a Fresnel lens. 9. The laser device according to claim 4, characterized in that: The laser beam incident on the focusing lens is a parallel laser beam, a converging laser beam or a diverging laser beam; Wherein, the parallel laser beam is directly formed by a solid laser after optical beam expansion/contraction and optical homogenization; The converged laser beam is composed of laser beams emitted by multiple laser emission points and incident on the focusing lens together; and the depth of the subcutaneous preset position corresponding to the converged laser beam is less than the depth of the subcutaneous preset position corresponding to the parallel beam; The divergent laser beams are scattered laser beams emitted by a laser emitting point and are incident on the focusing lens together; and the depth of the subcutaneous preset position corresponding to the divergent laser beam is greater than the depth of the subcutaneous preset position corresponding to the parallel beam. 10. The laser device according to claim 9, characterized in that: The beam power or energy of the parallel laser beam presents a flat-top distribution. 11. The laser device according to claim 1, characterized in that: An optical glass with a refractive index close to that of the skin is inserted between the focusing lens and the skin, which is used to adjust the distance between the focusing lens and the skin, adjust the subcutaneous depth of the focus of the focusing lens, or be used for heat dissipation and cooling conducted on the skin surface; wherein the optical glass cooperates with the focusing lens to form a complete lens assembly. 12. The laser device according to claim 1, characterized in that: A preset gap is formed between the focusing lens and the skin, so that the laser beam focused by the focusing lens forms a surface spot on the skin surface, and forms a focusing spot at a preset position under the skin after being refracted into the subcutaneous tissue, thereby realizing non-contact focusing of the laser beam. 13. The laser device according to claim 1, characterized in that: The output end of the focusing lens is equipped with a 45-degree reflector and a coaxial thermal imager; or, the output end of the focusing lens is equipped with a paraxial thermal imager; The 45-degree reflector is made of infrared optical material, and the surface is coated with a high-reflection film for reflecting incident laser light. 14. A method for achieving subcutaneous focusing, characterized by comprising the following steps: The laser device according to any one of claims 1 to 13 is arranged above the skin, and a focusing lens of the laser device is attached to the surface of the skin; The laser is controlled to emit a laser beam with a wavelength of 900 to 1300 nm toward the skin, so that the laser beam is collimated by the collimator and then emitted to the focusing lens, and forms a focusing spot of a preset size at a preset position under the skin through the focusing lens. 15. The method of claim 14, further comprising: The housing is controlled to translate as a whole along the skin surface to increase the size of the focused light spot and the focal density of the focused light spot. 16. The method of claim 15, wherein: The focusing lens includes a plurality of fly-eye lenses, which are arranged together into a regular hexagonal fly-eye lens array to form a regular hexagonal focusing spot at the preset position under the skin; wherein the four consecutive vertices of the regular hexagonal spot are defined as A, B, C, and D; and the position of vertex A when the focusing spot does not move is position 1, the position of vertex B after the focusing spot moves for the first time is position 2, the position of vertex C after the focusing spot moves for the second time is position 3, and the position of vertex D after the focusing spot moves for the fourth time is position 4; The shell is driven by a translation mechanism to translate in the directions of A-1, B-2, C-3, and D-4 in sequence, and the distance of each translation is half of the aperture of the compound eye lens, thereby increasing the size of the treatment area and doubling the focal density of the focused light spot.