Laser apparatus for subcutaneous focusing, and method

Abstract

Disclosed in the present invention are a laser apparatus for subcutaneous focusing, and a method. The laser apparatus comprises a housing, a laser device and a focusing lens, wherein the laser device is accommodated in a hollow inner cavity of the housing and is used for emitting laser light; and the focusing lens is used for implementing subcutaneous focusing on the laser light, so as to form a focused light spot at a preset subcutaneous position. The energy density of a collimated light beam of the laser device is lower than a preset skin damage threshold value. By using laser light, the energy density of which is below the skin damage threshold value, to irradiate the skin surface, the safety of the skin surface is ensured; and by means of further optical focusing and when the increase amplitude of laser energy density at the focal beam waist position exceeds the laser energy attenuation amplitude, the laser energy density at the subcutaneous focal beam waist position greatly exceeds the skin damage threshold value, causing subcutaneous recoverable burns, and thus stimulating the tissue repair function and improving the skin condition.

Description

A laser device and method for subcutaneous focusing TECHNICAL FIELD

[0001] The present application relates to a laser device for subcutaneous focusing, and also relates to a method for subcutaneous focusing using the laser device, and belongs to the technical field of medical devices. BACKGROUND

[0002] As shown in Fig. 1, the structure of human skin to the superficial fascia layer is three layers from top to bottom: epidermis, dermis and subcutaneous tissue. The epidermis and dermis are collectively referred to as "skin", and the thickness is about 0.4-4mm (this value does not include subcutaneous tissue) due to individual differences and different parts. The subcutaneous tissue below the dermis is mainly composed of fat layer and is continuous with the superficial fascia layer.

[0003] For energy-type treatment of the skin, there are generally laser, intense pulsed light, radio frequency, microneedle radio frequency, focused ultrasound and other technical means. The purpose of skin medical and cosmetic treatment includes removing tattoos and tattoos, improving pigmentation, exfoliating, hair removal, removing wrinkles, stimulating collagen regeneration, stimulating and lifting the fascia layer to improve tissue sagging, fat ablation, slimming and weight loss. For skin medical and cosmetic treatment, different technical means need to be used for different treatment depths. For removing tattoos and tattoos, improving pigmentation, exfoliating and other operations at the epidermis position, since the depth of action is shallow, laser and intense pulsed laser can be used for body surface irradiation to effectively treat. Since collagen is located in the deeper dermis layer, for removing wrinkles, stimulating collagen regeneration and other operations, radio frequency or microneedle radio frequency with a depth of 0.5-5mm is generally used to achieve a greater heating depth. For deeper fat layer ablation, fascia layer lifting and improvement, subcutaneous puncture type laser liposuction, focused ultrasound and other methods are used to achieve.

[0004] However, due to different reflection, absorption, heat dissipation and other optical characteristics of laser in skin tissue, the laser incident on the surface of the skin will rapidly attenuate with increasing depth, so it is difficult for most wavebands of laser to be used for treatment of deep tissue in the skin. The traditional skin surgical laser treatment scheme is generally: large-area surface irradiation or using laser scanning focusing or microlens focusing to act on the surface of the skin for energy-type treatment. These laser treatment schemes cannot significantly improve the energy density under the skin under the premise of meeting the safety of the skin surface, so they cannot meet the requirements of energy-type treatment at a deeper position under the skin. SUMMARY

[0005] The primary technical problem to be solved by the present application is to provide a laser device for subcutaneous focusing.

[0006] Another technical problem to be solved by the present application is to provide a method for subcutaneous focusing using the laser device.

[0007] To achieve the above technical purposes, the present application adopts the following technical solutions:

[0008] According to a first aspect of the embodiment of the present application, a laser device for subcutaneous focusing is provided, comprising:

[0009] a housing having a hollow inner cavity and a bottom opening communicating with the hollow inner cavity;

[0010] a laser device accommodated in the hollow inner cavity and configured to emit laser beams of a preset wavelength towards the bottom opening;

[0011] a focusing lens sealed at the bottom opening and located on a side of the collimator away from the laser device, configured to focus the laser beams subcutaneously to form a focused spot of a preset size at a preset subcutaneous position;

[0012] wherein the preset subcutaneous position is located in the dermis layer, fat layer or skin fascia layer below the skin surface, and the preset subcutaneous position is the focal waist position of the focusing lens; and the energy density of the laser beams emitted by the laser device is lower than a preset skin damage threshold at the skin surface and exceeds the skin damage threshold at the focal waist position.

[0013] Preferably, the skin damage threshold is determined by skin color, and the whiter the skin color, the higher the skin damage threshold.

[0014] Preferably, the focal point of the focusing lens is 0.5-8 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 device.

[0015] Preferably, the focusing lens cooperates with an optical coupling liquid located between the plane of the focusing lens and the skin to make the focused spot in a shallow area 0.5-8 mm below the skin, and the tissue at the focal waist position is heated to 45-85℃, causing subcutaneous recoverable burns; wherein the optical coupling liquid has a refractive index close to that of the skin.

[0016] Preferably, the focusing lens comprises a plurality of compound eye lenses, and the plurality of compound eye lenses are arranged together to form a compound eye lens array of a preset shape.

[0017] Preferably, each compound eye lens forms a sub-spot at the preset position, each sub-spot corresponds to a focal point, and all the sub-spots formed by the compound eye lenses constitute the focused spot, and the distance between two adjacent focal points is equal to the period of the compound eye lens.

[0018] Preferably, the laser device further comprises:

[0019] A translation mechanism is connected with the shell and drives the shell to translate along a preset direction.

[0020] 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 focal points, so that the focal point density of the focused light spot is doubled.

[0021] Preferably, the laser device further comprises:

[0022] A cooling unit is arranged on the shell and close to the skin, and is used to cool the contact area between the skin and the focusing lens.

[0023] Preferably, the focusing lens is a single lens or a Fresnel lens.

[0024] Preferably, the laser beam incident on the focusing lens is a parallel laser beam, a convergent laser beam or a divergent laser beam; wherein,

[0025] The parallel laser beam is directly formed by a solid-state laser after optical expansion / contraction and optical homogenization;

[0026] The convergent laser beam is formed by laser beams emitted from a plurality of laser emitting points and incident on the focusing lens together; and the depth of the preset subcutaneous position corresponding to the convergent laser beam is less than the depth of the preset subcutaneous position corresponding to the parallel laser beam.

[0027] The divergent laser beam is formed by divergent laser beams emitted from a laser emitting point and incident on the focusing lens together; and the depth of the preset subcutaneous position corresponding to the divergent laser beam is greater than the depth of the preset subcutaneous position corresponding to the parallel laser beam.

[0028] Preferably, the beam power or energy of the parallel laser beam is flat-topped.

[0029] Preferably, an optical glass with a refractive index close to that of the skin is inserted between the focusing lens and the skin, for adjusting the distance between the focusing lens and the skin, adjusting the subcutaneous depth of the focal point of the focusing lens, or for skin surface conduction heat dissipation refrigeration; wherein, the optical glass cooperates with the focusing lens to serve as a complete lens assembly.

[0030] 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 refraction into the subcutaneous tissue, a focused light spot is formed at a preset subcutaneous position, thereby realizing non-contact focusing of the laser beam.

[0031] Preferably, the output end of the focusing lens is provided with a 45-degree mirror and a coaxial observation thermal imager; or, the output end of the focusing lens is provided with a thermal imager for observing in a direction parallel to the optical axis.

[0032] Preferably, the 45-degree mirror is made of infrared optical material having good transmittance in the sensor thermal imaging waveband, and the surface is coated with high-reflection film for reflecting incident laser.

[0033] According to a second aspect of the embodiment of the present application, a method for achieving subcutaneous focusing is provided, comprising the following steps:

[0034] The laser device is arranged above the skin, and the focusing lens of the laser device is attached to the surface of the skin.

[0035] The laser is controlled to emit a laser beam of a preset wavelength towards the skin, so that the laser beam is collimated by the collimator and then is directed to the focusing lens, and a focused spot of a preset size is formed at a preset position under the skin by the focusing lens.

[0036] Preferably, the method further comprises:

[0037] The housing is controlled to translate as a whole along the surface of the skin, so as to increase the size of the focused spot and the focal point density of the focused spot.

[0038] Preferably, the focusing lens comprises a plurality of compound eye lenses, and the plurality of compound eye lenses are arranged together to form a regular hexagonal compound eye lens array, so as to form a regular hexagonal focused spot at the preset position under the skin; wherein, four consecutive vertices of the regular hexagonal focused spot are defined as A, B, C and D; and, when the focused spot is not moved, the position of the A vertex is position 1, after the focused spot is moved for the first time, the position of the B vertex is position 2, after the focused spot is moved for the second time, the position of the C vertex is position 3, and after the focused spot is moved for the fourth time, the position of the D vertex is position 4.

[0039] The housing is driven by the 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, so as to increase the size of the treatment area and double the focal point density of the focused spot.

[0040] Compared with the prior art, the present application has the following technical effects:

[0041] 1. Through research, it is found that there is a spectrum region with relatively small optical loss in the spectrum position of 900-1300 nm of skin tissue, and laser in this band can achieve deeper skin penetration depth. On this basis, the application preferably uses laser with wavelength of 900-1300 nm, thereby having relatively low skin loss. By focusing the laser under the skin, the skin surface energy density is not increased, the skin surface safety is ensured, and the laser energy density of the skin tissue at the subcutaneous focusing position is effectively improved, so as to effectively treat the deep skin tissue.

[0042] 2. The focusing lens adopts a large-aperture, short-focal-length lens and is close to the skin, so as to not only reduce the skin surface energy density to improve the treatment safety of the skin surface, but also improve the energy density at the preset position under the skin to improve the treatment effectiveness of the deep skin tissue. The lens and the skin are coupled through a liquid with refractive index matching to reduce the interface loss when focusing at a large angle.

[0043] 3. The translation of the focusing spot can be realized by mechanical translation, manual movement and the like, so that the laser focal point density of the region to be treated is significantly increased, thereby realizing two-dimensional coverage treatment along the skin surface.

[0044] 4. The laser beam emitted by the laser is collimated through the lens and then focused through the compound eye lens array, thereby realizing the uniform dot array focusing effect.

[0045] 5. The calculation of the subcutaneous focusing position considers the influence of the skin refractive index, and according to different skin colors, the general skin refractive index is about 1.3-1.6, thereby improving the calculation accuracy of the subcutaneous focusing position. Specific optical instruments can be designed to determine the refractive index through pinch test or earlobe before treatment, thereby calculating the focusing depth of the lens and selecting the lens. The refractive index measuring instrument can work independently but cooperatively with the laser device, or can be designed as part of the laser device.

[0046] 6. The focusing lens can be a single convex lens, a Fresnel lens, a compound eye lens array, a cylindrical lens array and the like, to adapt to the treatment needs of different situations.

[0047] 7. The laser can output a flat-top distributed parallel light beam, thereby improving the energy distribution uniformity of the subcutaneous focusing position. BRIEF DESCRIPTION OF DRAWINGS

[0048] Fig. 1 is a schematic diagram of the action depth of the existing human skin tissue and common photoelectric equipment;

[0049] Fig. 2 is a schematic diagram of the optical loss of various laser light sources in different bands to realize subcutaneous focusing;

[0050] Fig. 3 is a structural schematic diagram of a laser device for subcutaneous focusing according to the first embodiment of the present application;

[0051] Fig. 4A is a schematic diagram of a focused light spot formed by the fly-eye lens array according to the first embodiment of the present application;

[0052] Fig. 4B is a structural schematic diagram of a laser beam position provided with a 45-degree mirror and a coaxial thermal imager according to the second embodiment of the present application;

[0053] Fig. 4C is a structural schematic diagram of an optical glass inserted between the focusing lens and the skin according to the second embodiment of the present application;

[0054] Fig. 4D is a structural schematic diagram of a preset gap formed between the focusing lens and the skin according to the second embodiment of the present application;

[0055] Fig. 5 is a structural schematic diagram of a laser device for subcutaneous focusing according to the second embodiment of the present application;

[0056] Fig. 6 is a schematic diagram of a hexagonal fly-eye lens array before and after movement;

[0057] Fig. 7 is a structural schematic diagram of a laser device for subcutaneous focusing according to the fourth embodiment of the present application;

[0058] Fig. 8 is a structural schematic diagram of a laser device for subcutaneous focusing according to the fourth embodiment of the present application;

[0059] Fig. 9 is a structural schematic diagram of a laser device for subcutaneous focusing according to the fourth embodiment of the present application;

[0060] Fig. 10 is a structural schematic diagram of a laser device for subcutaneous focusing according to the fifth embodiment of the present application;

[0061] Fig. 11 is a flow chart of a method for subcutaneous focusing according to the sixth embodiment of the present application. DETAILED DESCRIPTION

[0062] The technical content of the present application will be described in detail below in combination with the drawings and specific embodiments.

[0063] In consideration of the absorption and scattering loss of different substances in the skin and subcutaneous tissue, including water, melanin, hemoglobin (deoxy and oxyhemoglobin), protein (such as collagen in the dermis), fat, etc., referring to Fig. 2, the inventors studied the optical loss of various laser light sources in different wavelength bands to achieve subcutaneous focusing, and observed that there is a relatively small optical loss spectral region (i.e., the region shown by the dashed line in Fig. 2) in the spectral position near 900-1300 nm. In this wavelength band, the absorption coefficients of water, melanin, hemoglobin, collagen, etc. in the skin tissue are relatively small, that is, the optical loss is the lowest in this wavelength band, so that a deeper skin penetration depth can be achieved. Therefore, the present embodiment provides a laser device and method for subcutaneous focusing, which can achieve a low skin surface laser power density (to ensure the safety of treatment) but a high skin tissue deep laser power density (to ensure the effectiveness of treatment) with relatively low optical loss, thereby forming an effective energy type treatment method.

[0064] Based on this, the present embodiment provides a laser device and method for subcutaneous focusing, which uses a laser with a wavelength of 900-1300 nm, so as to have a relatively low skin loss. By achieving subcutaneous focusing of the laser, the skin surface energy density is not increased, the safety of the skin surface is ensured, and the laser energy density of the skin tissue at the subcutaneous focusing position is effectively improved, so as to achieve effective treatment of the deep skin tissue. The present application is particularly suitable for stimulating the growth of subcutaneous dermal collagen, laser heating and apoptosis or ablation of subcutaneous fat, heating stimulation and lifting of the skin fascia layer, and other laser treatments.

[0065] First embodiment

[0066] As shown in Fig. 3, the laser device for subcutaneous focusing provided by the first embodiment of the present application comprises 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 900-1300 nm, and more preferably a 924 nm wavelength laser for fat ablation. The collimator 2 is used to collimate the laser to form a collimated laser. The focusing lens 3 is used to achieve subcutaneous focusing of the collimated laser to form a focused spot. The housing 4 serves as the mounting basis for the laser 1, the collimator 2, and the focusing lens 3, and provides safety protection for the internal devices.

[0067] Specifically, in the present embodiment, referring to Fig. 3, the housing 4 has a hollow inner cavity 401 and a bottom opening 402 communicating with the hollow inner cavity 401. Correspondingly, the laser 1 and the collimator 2 are arranged in the hollow inner cavity 401, and the focusing lens 3 is plugged at the bottom opening 402. Thus, the housing 4 is used as the mounting basis, so that the laser 1, the collimator 2, and the focusing lens 3 are collectively mounted in the housing 4.

[0068] In the present embodiment, the laser 1 is arranged above the skin 10 for emitting laser with wavelength of 900-1300nm towards the skin 10, and the beam of the laser 1 is flat-top distribution. It is noted that, through the research of the inventor, it is found that there is a spectral region with relatively small optical loss for the wavelength of 900-1300nm, thus, by selecting the laser 1 with specific wavelength, a deeper skin penetration depth (e.g. 3-5mm) can be achieved to realize the laser treatment of the deep skin. In the spectral region, the absorption coefficient of oxygenated hemoglobin is about 0.2-0.4 / cm; the absorption coefficient of deoxygenated hemoglobin is about 0.7-0.85 / cm, the absorption coefficient of melanin is about 4-7 / cm, and the absorption coefficient of water is about 0.16-0.2 / cm.

[0069] In addition, in the present embodiment, the energy density of the collimated beam of the laser 1 is lower than the preset skin damage threshold (unit: 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 skin surgery, according to different skin colors: the skin damage threshold of type I skin color is about 20 J / cm 2 ; the skin damage threshold of type II-III skin color is about 10 J / cm 2 ; and the skin damage threshold of type IV-V-VI skin color is about 5 J / cm 2 , so as to avoid burning the skin surface. Thus, by irradiating the skin surface with laser lower than the skin damage threshold, in the case of ensuring the safety of the skin surface, by further optical focusing, in the case that the laser energy density at the focal waist position increases by more than the laser energy attenuation, the laser energy density at the focal waist position under the skin is greatly higher than the skin damage threshold, thereby causing the recoverable burn under the skin.

[0070] In addition, preferably, the laser 1 adopts Nd:YAG laser with wavelength of 1064nm or semiconductor laser with wavelength of 900-1300nm. It can be understood that the wavelength of the semiconductor laser can be designed and customized as needed (achieved by epitaxial design and growth of semiconductor materials). In another preferred embodiment, a fiber-coupled output semiconductor laser (wavelength can be arbitrarily customized, and the electro-optical conversion efficiency is more than 50%) is selected, which has longer optical life and lower cost compared with Nd:YAG.

[0071] In addition, in the above embodiment, preferably, the output of the laser 1 is flat-top laser beam, so as to improve the energy distribution uniformity at the subcutaneous focusing position.

[0072] As shown in FIG. 3, in the present embodiment, the collimator 2 is arranged on the light emitting side of the laser 1, and is used to collimate the laser light, thereby forming collimated laser light. Specifically, in the present embodiment, the collimator 2 is a collimating lens, which is used to form a cylindrical parallel laser beam by collimating the laser light, and then the laser beam is used to irradiate the focusing lens 3 to achieve subcutaneous focusing. It can be understood that arranging the collimator 2 as a collimating lens is only one of the preferred embodiments, and in other embodiments, other forms of collimating structure can be selected according to the needs.

[0073] 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 light, thereby forming a focused light spot 20 of a preset size at the preset position O (beam waist) under the skin.

[0074] Generally, the laser is a Gaussian beam, and under different focusing angles, the characteristics of the Gaussian beam are: the product of the beam parameters = the beam waist * the far-field divergence angle is a constant value. It can be approximately considered that the far-field divergence angle is about the focusing angle, so the greater the focusing angle, the shorter the focal length, and the smaller the beam waist near the focal point; on the contrary, the smaller the focusing angle, the longer the focal length, and the larger the beam waist near the focal point.

[0075] It can be understood that in the embodiment, preferably, the focusing lens 3 adopts a large-aperture and small-focal-length design, and a liquid with a refractive index matched with the skin and the focusing lens is used for optical path matching. It can be understood that the larger the numerical aperture of the optical system formed by the focusing lens is, the better. By controlling the focusing lens 3 to be shorter in focal length and larger in aperture, the numerical aperture value is increased. Specifically, in the embodiment, the focal point of the focusing lens is 0.5-8 mm away from the skin surface, and the diameter of the focusing lens is greater than 2 mm. Moreover, the convex side of the focusing lens 3 faces the laser 1, and the flat side of the focusing lens 3 is attached to the skin. In addition, by filling the optical coupling liquid (such as olive oil, which has high optical transmittance and is friendly to human skin) with a refractive index close to that of the skin (generally 1.3-1.6) between the flat side of the focusing lens 3 and the skin, a larger optical entrance, a shorter focusing focal length (i.e., a shallower subcutaneous focal depth), and a smaller focused spot (i.e., a beam waist region after focusing) can be achieved, so as to realize focusing with a large numerical aperture, so that the skin surface has a low energy density and the subcutaneous tissue has a high energy density. Thus, in the shallow skin layer (0.5-8 mm of the skin and subcutaneous tissue region), the tissue at the beam waist position is heated to 45-85°C by the focused spot. At this temperature, the skin tissue components will undergo burn changes such as shrinkage, coagulation, and denaturation, and then stimulate the tissue's own repair mechanism to improve the skin properties. In this way, both the surface layer has a low temperature (low energy density) and the beam waist position has a high temperature (high energy density), so that the skin surface is not damaged and the beam waist position is subjected to a recoverable burn.

[0076] In addition, it can be understood that in the embodiment, the power, the emission wavelength, and the flat-top distribution of the laser 1 are matched with the subcutaneous focusing position (beam waist), so as to ensure the depth of the subcutaneous focusing and the energy intensity at the beam waist position. Moreover, in the embodiment, the calculation of the subcutaneous focusing position also considers the influence of the skin refractive index, and the skin refractive index is generally about 1.3-1.6 according to different skin colors, so as to improve the calculation accuracy of the subcutaneous focusing position. On this basis, an additional skin refractive index measuring instrument can be provided, and when the subcutaneous focusing position needs to be calculated, the refractive index of the patient is tested by pinching the skin or using the earlobe skin, so as to calculate and match the focusing depth of the focusing lens 3.

[0077] In the above embodiment, preferably, the laser beam incident on the focusing lens is a parallel laser beam with a flat-top power or energy distribution. The parallel laser beam with a flat-top distribution can be directly formed by a solid-state laser after optical expansion / contraction and optical homogenization. It can also be formed by a fiber transmission laser combined with a collimator. It can also be formed by other types of laser light sources.

[0078] Specifically, the laser 1 and the collimator 2 can constitute a parallel laser light source with flat-top distribution, for generating parallel light beams, so as to improve the energy distribution uniformity of the subcutaneous focusing position. For some types of lasers, such as Nd:YAG solid lasers with better beam quality, parallel laser beams with flat-top distribution can be obtained without collimation, and therefore the collimator 2 is not necessary. Since there is an adjustment of the diameter of the parallel light beams, a beam expander or a beam reducer can be used to adjust the thickness of the parallel light beams. It can be understood that the parallel laser light source in the embodiment can be constituted by a fiber-coupled semiconductor laser + collimator, or can be directly provided by a laser, and the core requirement is that the parallel laser light source must be uniformly flat-topped. Among them, the fiber-coupled semiconductor laser + collimator is more common, the wavelength selection is the most flexible, and the cost is the lowest.

[0079] Second embodiment

[0080] On the basis of the first embodiment, the focusing lens 3 in the embodiment has a compound eye lens structure.

[0081] As shown in FIG. 3, in the embodiment, 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, for focusing the collimated laser subcutaneously, so as to form a focused light spot 20 of a preset size at a preset position O in the skin. Specifically, in the embodiment, the focusing lens 3 includes a plurality of compound eye lenses 31, which are arranged together in a hexagonal compound eye lens array. The hexagonal compound eye lens array can be arranged in the array forms of 2-3-2, 3-4-5-4-3, 4-5-6-7-6-5-4, etc. The number of the compound eye lenses 31 corresponding to different array forms is different, and can be adaptively selected according to needs. As shown in FIG. 4A, each compound eye lens 31 forms a sub-light spot 30 at the preset position O, and each sub-light spot corresponds to a focal point 32 (i.e., a black dot at the center of each light spot 30). All the compound eye lenses form sub-light spots together to constitute the focused light spot 20, and the distance between two adjacent focal points is equal to the focal point distribution period of the compound eye lens 31.

[0082] In the embodiment, the subcutaneous preset position O includes at least dermis layer, skin fat layer, skin fascia layer, etc., to be suitable for laser treatment means of heating dermis layer and stimulating collagen growth, laser heating apoptosis or ablation of subcutaneous fat, skin fascia layer tightening and lifting, etc. In various embodiments of the present application, based on Fitzpatrick skin color classification rules, skin color I-II-III belongs to light skin, and IV-V-VI belongs to dark skin. Since the absorption coefficient of melanin is higher at shorter wavelength and lower at longer wavelength, for light skin or parts with thinner skin thickness, 910-930 nm is a better fat ablation laser wavelength; for dark skin or parts with thicker skin thickness, 1000-1100 nm (especially 1060 nm or 1064 nm) is a laser wavelength that has been verified in practice to be effectively transmitted to the fat layer and produce ablation. Thus, the heating and ablation effect on the fat layer can be improved. It can be understood that in the embodiment, the focusing lens 3 uses a large-aperture, short-focal-length lens and is close to the skin, so not only the skin surface energy density is reduced to improve the treatment safety of the skin surface, but also the energy density at the subcutaneous preset position O is improved to improve the treatment effectiveness of the deep tissue of the skin.

[0083] Next, taking the treatment with the above laser device and a laser beam with a wavelength of 924 nm (the optimal wavelength for fat absorption) as an example, a detailed description is made as follows:

[0084] It is known that the average absorption coefficient of skin near 924 nm is about / 1 cm, so considering the action on the subcutaneous 4 mm position (i.e., the subcutaneous preset position O), the light intensity at this position after attenuation is EXP(-1*0.4)=67%.

[0085] If a 5 mm circular spot is used on the body surface, and at a distance of 4 mm from the subcutaneous position, assuming that the preset size of the focused spot is 1 mm in diameter, the single-pulse laser energy density that a general human body (I-III skin color) can withstand without being easily burned is 10 J / cm 2 , then the body surface energy is 3.14*0.25*0.25*10=1.96 J, and the subcutaneous focal position (beam waist position) energy is 1.96*67%=1.31 J, so the energy density at the focal position reaches 1.31 / (3.14*0.05*0.05)=167 J / cm 2 .

[0086] As can be seen from the data comparison, the laser device provided by the first embodiment of the present application can realize: the laser energy density on the skin surface is low (10 J / cm 2)But the technical effect is that the laser energy density at the subcutaneous focal point is more than 16 times (167 / 10 = 16.7 times) the energy density at the skin surface. It should be noted that this energy density is sufficient to burn any subcutaneous tissue while protecting the surface skin.

[0087] In a preferred embodiment of the present application, as shown in FIG. 4B, a 45-degree mirror 310 and a coaxial observation thermal imager 320 can be installed at the output end of the focusing lens 3 to achieve dynamic monitoring of the tissue heating temperature, ensuring the safety and effectiveness of laser treatment. More preferably, the 45-degree mirror 310 requires a material such as ZnS or BaF2 that is transparent in the 8-14um (thermal imaging capture waveband) and the surface is coated with a high-reflective film to reduce the transmission of laser light, allowing more laser beams to be directed at the skin surface.

[0088] More preferably, in addition to the hard lens, the lens array can also be made of flexible optical material with a refractive index close to that of the skin, which is attached to the skin through an 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.

[0089] In another preferred embodiment, as shown in FIG. 4C, a refractive optical glass 340 with 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 FIG. 4B, the distance between the focusing lens 3 and the skin or the subcutaneous depth of the focal point of the focusing lens 3 can be adjusted by inserting optical glass 340 of different thicknesses. Moreover, since the optical glass 340 has good heat conduction performance, it can be used to conduct heat from the skin surface by being in contact with the skin surface, thereby achieving the purpose of cooling the skin. In this embodiment, the optical glass 340 can be used as a complete lens assembly together with the focusing lens 3.

[0090] In another preferred embodiment, as shown in FIG. 4D, a pre-set gap is formed between the focusing lens 3 and the skin, and the specific value of the distance d of the pre-set gap can be set as needed. Thus, when the incident light shines on the focusing lens 3, the focused laser beam will propagate in the air and shine on the skin surface to form a surface spot 350. Moreover, the laser beam will continue to refract into the subcutaneous tissue to form a focused spot at a pre-set position in the subcutaneous tissue, thereby achieving non-contact focusing of the laser beam. It can be understood that since no optical material is provided in this embodiment, refraction will occur when the light beam shines on the skin, thereby affecting the subcutaneous focusing depth. The distance d needs to be adjusted adaptively according to the refraction of the skin in specific applications.

[0091] Third embodiment

[0092] On the basis of the first embodiment, the third embodiment of the present application 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 the present embodiment is that the focused spot can be translated, so as to increase the focal point density.

[0093] Specifically, in the present embodiment, referring to Fig. 5, the laser device further comprises a translation mechanism 5. The translation mechanism 5 is connected with the shell 4 and drives the shell 4 to translate along any one side of the hexagonal compound eye lens array, so as to increase the size of the focused spot and the focal point density of the focused spot. Specifically, referring to Fig. 6, the shell 4 is driven by the translation mechanism 5 to translate in the directions of A-1, B-2, C-3 and D-4 in turn, and the distance of each translation is half of the period of the compound eye lens 31, so that after three times of translation, the focal point density of the focused treatment area is significantly increased, and thus the two-dimensional coverage treatment along the skin surface is realized.

[0094] In the above embodiments, preferably, the laser device further comprises a cooling part. The cooling part is arranged on the shell 4 and close to the skin, and is used for cooling the contact area between the skin and the focusing lens 3. The cooling part can adopt a fan to cool the skin by air cooling, or can adopt a contact cooling mode, for example, cooling the skin by sapphire. It can be understood that the specific structure of the cooling part can be adaptively selected according to the needs, which is not limited here.

[0095] The present embodiment is different from the first embodiment only in the above aspects, and the rest of the structure is the same as the first embodiment, which will not be repeated here.

[0096] Fourth embodiment

[0097] On the basis of the first embodiment, the fourth embodiment of the present application further provides a laser device for subcutaneous focusing, comprising a laser 1, a focusing lens 3 and a shell 4. The difference between the present embodiment and the first embodiment is that the laser beam emitted by the laser 1 is not a parallel beam.

[0098] Specifically, as shown in Fig. 7, in the present embodiment, the laser beam incident to the focusing lens by the laser 1 is a converging laser beam, which is formed by the laser beams emitted by a plurality of laser emitting points. Similarly, in another embodiment, as shown in Fig. 8, the laser beam incident to the focusing lens by the laser 1 is a diverging laser beam, which is formed by the dispersed laser beams emitted by one laser emitting point.

[0099] As shown in FIGS. 7 and 8, because the incident angles of the incident laser beams are different, the angles of refraction into the focusing lens 3 are also different after the incident laser beams are irradiated on the focusing lens 3, so that the depths of the preset subcutaneous positions corresponding to the convergent laser beams are less than the depths of the preset subcutaneous positions corresponding to the divergent laser beams.

[0100] As further shown in FIG. 9, when the incident laser beams are parallel light beams, the depths of the preset subcutaneous positions corresponding to the parallel laser beams are between the depths of the preset subcutaneous positions corresponding to the convergent laser beams and the depths of the preset subcutaneous positions corresponding to the divergent laser beams. Thus, the installation position of the focal length of the laser can be adjusted as needed, so that switching between the three different incident modes is realized to treat different skin layers.

[0101] The rest of the structure of the embodiment is the same as that of the first embodiment, which will not be repeated here.

[0102] Fifth Embodiment

[0103] The fifth embodiment of the present application also provides a laser device for subcutaneous focusing, which comprises a laser 1, a collimator 2 and a focusing lens 3. Compared with the first embodiment, the difference of the present embodiment is that the focusing lens 3 is a single lens or a Fresnel lens.

[0104] As shown in FIG. 10, it can be understood that the focusing lens 3 formed by the single lens or the Fresnel lens can only form one light spot in subcutaneous focusing.

[0105] The rest of the structure of the embodiment is the same as that of the first embodiment, which will not be repeated here.

[0106] Sixth Embodiment

[0107] As shown in FIG. 11, based on the third embodiment, the sixth embodiment of the present application provides a method for subcutaneous focusing, which specifically comprises steps S1-S3:

[0108] S1: The laser device is arranged above the skin, and the focusing lens 3 of the laser device is attached to the surface of the skin.

[0109] S2: The laser 1 is controlled to emit a laser beam with a wavelength of 900-1300 nm toward the skin, so that the laser beam is irradiated on the focusing lens 3 after collimation by the collimator, and a focused light spot with a preset size is formed at a preset subcutaneous position by the focusing lens 3.

[0110] S3: The shell 4 is controlled to be translated as a whole along the surface of the skin to increase the size of the focused light spot and the focal point density of the focused light spot.

[0111] Specifically, as shown in FIG. 6, the control translation mechanism 5 drives the shell 4 to translate in the directions of A-1, B-2, C-3 and D-4 in turn, and the distance of each translation is half of the period of the compound eye lens 31. Thus, after three times of translation, the focal point density of the focused treatment area is significantly increased, and thus the two-dimensional coverage treatment along the skin surface is realized.

[0112] It can be understood that the overall translation mode of the laser 1, the collimator 2 and the focusing lens 3 in the embodiment is mechanical translation, that is, the shell 4 is driven to translate by the translation mechanism 5, and in other embodiments, other translation modes such as manual movement can also be used.

[0113] In summary, the laser device and method for subcutaneous focusing provided by the embodiment have the following beneficial effects:

[0114] 1. Through research, it is found that there is a relatively small optical loss spectrum region of skin tissue at a spectrum position of 900-1300 nm, and the laser at this waveband can achieve a deeper skin penetration depth. On this basis, the laser with a wavelength of 900-1300 nm is preferably used, so as to have a relatively low skin loss. By realizing subcutaneous focusing of the laser, the skin surface energy density is not increased, the skin surface safety is ensured, and the laser energy density of the skin tissue at the subcutaneous focusing position is effectively improved, so as to effectively treat the deep skin tissue (which can reach the fascia layer).

[0115] 2. The focusing lens 3 adopts a large-aperture and short-focal-length lens and is close to the skin, so as to not only reduce the skin surface energy density to improve the treatment safety of the skin surface, but also improve the energy density at the preset subcutaneous position to improve the treatment effectiveness of the deep skin tissue.

[0116] 3. The translation of the focused light spot can be realized by mechanical translation, manual movement and the like, so as to expand the coverage area of the focused light spot, significantly increase the focal point density of the focused treatment area, and thus realize the two-dimensional coverage treatment along the skin surface.

[0117] 4. The laser beam emitted by the laser 1 is collimated through the lens and then focused through the compound eye lens array, so as to improve the focusing effect.

[0118] 5. The calculation of the subcutaneous focusing position considers the influence of the skin refractive index, and according to different skin colors, the general skin refractive index is about 1.3-1.6, so as to improve the calculation accuracy of the subcutaneous focusing position.

[0119] 6. The focusing lens 3 can be a single convex lens, a Fresnel lens or a compound eye lens array, so as to adapt to the treatment requirements in different situations.

[0120] 7. After collimation by the collimator 2, the laser 1 can form a parallel light beam with a flat top distribution, thereby improving the energy distribution uniformity at the sub-surface focal position.

[0121] It should be noted that the above embodiments are only illustrative. The technical solutions of various embodiments can be combined, and all are within the protection scope of the present application.

[0122] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited.

[0123] The above provides a detailed description of the laser device and method for sub-surface focusing. Any obvious modification made by a person skilled in the art without departing from the essential content of the present application will constitute an infringement of the patent right of the present application and will bear the corresponding legal responsibility.

Claims

1. A laser device for subcutaneous focusing, characterized in that The laser device comprises: a housing having a hollow inner cavity and a bottom opening communicating with the hollow inner cavity; a laser accommodated in the hollow inner cavity and configured to emit laser beams of a preset wavelength towards the bottom opening; a focusing lens sealed at the bottom opening and located on a side of the collimator away from the laser, and configured to perform subcutaneous focusing on the laser beams to form a focused spot of a preset size at a preset subcutaneous position. The preset subcutaneous position is located in a dermis layer, a fat layer or a skin fascia layer below a skin surface, and is a focal waist position of the focusing lens. The energy density of the laser beams emitted by the laser is lower than a preset skin damage threshold at the skin surface and exceeds the skin damage threshold at the focal waist position. The skin damage threshold is determined by skin color.

2. The laser device of claim 1, wherein: a focal distance of the focusing lens is 0.5-8 mm from the skin surface, a diameter of the focusing lens is greater than 2 mm, and a convex side of the focusing lens faces the laser.

3. The laser device of claim 2, wherein: the focusing lens cooperates with an optical coupling liquid between a plane of the focusing lens and the skin to cause the focused spot to be in a shallow layer region 0.5-8 mm below the skin, and the tissue at the focal waist position is heated to 45-85 ℃ to cause subcutaneous recoverable burns; and the optical coupling liquid has a refractive index close to that of the skin.

4. The laser device of any one of claims 1-3, wherein: the focusing lens comprises a plurality of compound eye lenses, and the plurality of compound eye lenses are arranged together to form a compound eye lens array of a preset shape. Each of the compound eye lenses forms a sub-spot at the preset position, each sub-spot corresponds to a focal point, and all the sub-spots formed by the compound eye lenses constitute the focused spot, and a distance between two adjacent focal points is equal to a period of the compound eye lens.

5. The laser device of claim 4, wherein Further comprising: a translation mechanism connected to the housing and configured to drive the housing to translate along a preset direction.

6. The laser device of claim 5, wherein: the preset shape is a regular hexagon, the preset direction is a direction of an edge of the regular hexagon, and a distance of each translation of the housing is half of the distance between two adjacent focal points, so that a focal point density of the focused spot is doubled.

7. The laser device of claim 4, wherein Further comprising: a cooling unit arranged on the housing and close to the skin, and configured to cool and lower a temperature of a contact area of the skin and the focusing lens.

8. The laser device of claim 6, wherein: the focusing lens is a single lens or a Fresnel lens.

9. The laser device of claim 4, wherein: the laser beams incident on the focusing lens are parallel laser beams, convergent laser beams or divergent laser beams. The parallel laser beams are directly formed by a solid-state laser after optical beam expansion / contraction and optical homogenization. The converged laser beams are collectively incident on the focusing lens by laser beams emitted from multiple laser emitting points; and the depth of the subcutaneous preset position corresponding to the converged laser beams is less than the depth of the subcutaneous preset position corresponding to the parallel laser beams. The divergent laser beams are collectively incident on the focusing lens by divergent laser beams emitted from one laser emitting point; and the depth of the subcutaneous preset position corresponding to the divergent laser beams is greater than the depth of the subcutaneous preset position corresponding to the parallel laser beams.

10. The laser device of claim 9, wherein: The beam power or energy of the parallel laser beams is flat-topped distributed.

11. The laser device of claim 1, wherein: An optical glass with a refractive index similar to that of the skin is further inserted between the focusing lens and the skin, for adjusting the distance between the focusing lens and the skin, adjusting the subcutaneous depth of the focal point of the focusing lens, or for skin surface conduction heat dissipation refrigeration; wherein the optical glass cooperates with the focusing lens to jointly serve as a complete lens assembly.

12. The laser device of claim 1, wherein: A preset gap is formed between the focusing lens and the skin, so that the laser beams focused by the focusing lens form a surface spot on the skin surface, and after refraction into the subcutaneous tissue, a focused spot is formed at a subcutaneous preset position, thereby realizing non-contact focusing of the laser beams.

13. The laser device of claim 1, wherein: The output end of the focusing lens is provided with a 45-degree mirror and a coaxial observation thermal imager; or the output end of the focusing lens is provided with a thermal imager for observation in a side-by-side manner. The 45-degree mirror is made of infrared optical material, and the surface is coated with a high-reflection film for reflecting incident laser.

14. A method of achieving subcutaneous focusing, characterized by The method comprises the following steps: The laser device of any one of claims 1-13 is arranged above the skin, and the focusing lens of the laser device is attached to the skin surface; The laser device is controlled to emit laser beams of a preset wavelength towards the skin, so that the laser beams are collimated by the collimator and then shot towards the focusing lens, and a focused spot of a preset size is formed at a subcutaneous preset position by the focusing lens.

15. The method of claim 14, wherein Further comprising: The entire housing is controlled to translate along the skin surface to increase the size of the focused spot and increase the focal point density of the focused spot.

16. The method of claim 15, wherein: The focusing lens comprises multiple fly-eye lenses, and the multiple fly-eye lenses are collectively arranged in a regular hexagonal fly-eye lens array to form a regular hexagonal focused spot at the subcutaneous preset position; wherein four consecutive vertices of the regular hexagonal spot are defined as A, B, C, and D; and when the focused spot is not moved, the position of the A vertex is position 1, after the focused spot is moved for the first time, the position of the B vertex is position 2, after the focused spot is moved for the second time, the position of the C vertex is position 3, and after the focused spot is moved for the fourth time, the position of the D vertex is position 4. The shell is driven by the translation mechanism to be aligned with A-1, B-2, C-3 and D-4 in turn, and the distance of each translation is half of the compound eye lens aperture, so as to increase the size of the treatment area and double the focal point density of the focused light spot.

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