Three-dimensional curved surface integrated transparent heating mask and preparation method thereof

Abstract

The invention discloses a preparation method of a three-dimensional curved surface integrated transparent heating mask, and aims to solve the problems that in the prior art, a heating mask is uneven in heating and not attached, and layering is prone to occurring in the attaching process. The method comprises the following steps: preparing a three-dimensional curved surface rigid transparent substrate with a convex surface and a concave surface; performing plasma activation treatment on the substrate; a planetary rotary magnetron sputtering process is adopted, and a transparent conductive heating layer is directly deposited on the convex surface of the substrate, so that an integrated structure of the heating layer and the substrate is realized. The transparent electrothermal film is directly and integrally integrated on the three-dimensional rigid curved surface, so that the defects of a laminating process are fundamentally avoided, and the manufactured mask is uniform in heating, high in transparency, good in laminating degree and reliable in structure. The invention also discloses the mask prepared by the method.

Description

Technical Field

[0001] The present invention relates to the technical field of heating masks, and more particularly to a three-dimensional curved integrated transparent heating mask and a preparation method thereof. Background Art

[0002] With the growing demand for beauty and skin care, heated masks, as a device that can promote the absorption of skin care products and soothe the skin, have become popular in the market.

[0003] Existing heated mask products mainly have the following technical problems: First, the heating method is outdated, and traditional resistance wire or carbon fiber is mostly used for heating. These linear heat sources lead to uneven heat distribution, large temperature differences between different areas of the face, and easy local overheating, affecting the comfort and safety of use; second, the structure and material are opaque, which will completely block the wearer's vision when used, causing many inconveniences; third, the fit is poor. Most masks are flat or flexible structures, which are difficult to achieve a close fit with the complex three-dimensional curved contours of the human face, resulting in gaps between the heated area and the skin, and low heat transfer efficiency.

[0004] To address some of the above issues, some technical solutions attempt to prepare a transparent conductive layer (such as an ITO film) on a flexible transparent film (such as a PET film), and then attach it to a rigid mask substrate by laminating. However, this "film-formation-first, lamination-later" process has a fatal flaw in practice: when a flat flexible film is laminated to a three-dimensional rigid surface with complex curvature, bubbles, wrinkles, and warping are easily generated, causing the heating film layer to delaminate and fall off from the substrate. This not only seriously affects the product appearance and light transmittance, but also destroys the integrity of the conductive path, causing heating performance to deteriorate or even fail.

[0005] Therefore, how to provide a heating mask and a preparation method thereof that can closely fit the facial contour, heat evenly, and have high transparency and high structural reliability has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of the present invention is to provide a three-dimensional curved integrated transparent heating mask and a preparation method thereof, aiming to solve the technical defects of the existing heating mask such as uneven heating, opacity, poor adhesion, and easy delamination and bubbling when the flexible film is adhered to the three-dimensional curved surface.

[0007] The present invention provides a method for preparing a three-dimensional curved integrated transparent heating mask, comprising the following steps:

[0008] A rigid transparent substrate having a three-dimensional curved surface is prepared, wherein the three-dimensional curved surface includes a convex surface and a concave surface;

[0009] Plasma activation treatment of a rigid transparent substrate;

[0010] A planetary rotating magnetron sputtering process is used to directly deposit a transparent conductive heating layer on the convex surface of a rigid transparent substrate that has been activated by plasma, so that the transparent conductive heating layer and the rigid transparent substrate form an integrated structure.

[0011] Optionally, the step of preparing a rigid transparent substrate having a three-dimensional curved surface includes: processing a transparent polymer material into a rigid transparent substrate by an injection molding process or a hot pressing molding process.

[0012] Optionally, the material of the rigid transparent substrate is one of polycarbonate, polymethyl methacrylate or polyethylene terephthalate.

[0013] Optionally, the material of the transparent conductive heating layer is transparent conductive oxide.

[0014] Optionally, the transparent conductive oxide is one or more of indium tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, indium molybdenum oxide, or gallium-doped zinc oxide.

[0015] Optionally, the method further includes forming an electrode on the transparent conductive heating layer, wherein the step of forming the electrode includes screen printing a conductive silver paste at a preset position of the transparent conductive heating layer and curing the conductive silver paste.

[0016] Optionally, after curing the conductive silver paste, the method further includes pasting a layer of conductive copper foil tape on the cured conductive silver paste, wherein the thickness of the conductive copper foil tape ranges from 0.05 mm to 0.2 mm and the width ranges from 2 mm to 5 mm.

[0017] Optionally, the method further includes forming a transparent insulating protective layer on the transparent conductive heating layer, wherein the forming step includes coating a layer of transparent insulating material on the transparent conductive heating layer and curing the transparent insulating material.

[0018] Optionally, the curing step is performed by ultraviolet light irradiation, and the wavelength of the ultraviolet light is in the range of 360nm to 370nm, and the irradiation energy is in the range of 900mJ / cm 2 Up to 1100mJ / cm 2 .

[0019] The second aspect of the present invention provides a three-dimensional curved integrated transparent heating mask prepared by any method of the first aspect of the present invention.

[0020] The technical content disclosed in the present invention has the following beneficial effects:

[0021] The present invention combines plasma activation and planetary rotating magnetron sputtering processes on a pre-formed three-dimensional curved substrate to directly deposit a transparent conductive heating layer onto its convex surface, achieving a seamless, integrated integration of the heating functional layer and the three-dimensional mask body 7. This direct film formation method fundamentally avoids the critical defects such as bubbles, wrinkles, and delamination caused by surface mismatch in traditional flexible film lamination processes, ensuring excellent adhesion and structural integrity between the heating layer and the substrate. The resulting heated mask not only perfectly conforms to the contours of the face but also ensures highly uniform heat distribution across the entire face (temperature difference ΔT ≤ 1.2°C). The far-infrared radiation generated during heating (FTIR analysis shows that the infrared emission peak is in the 9.4μm wavelength range) effectively promotes the absorption of skincare products (increasing essence absorption by 68%). Furthermore, the overall high light transmittance ensures a clear field of vision when worn, and the mask has passed cytotoxicity and voltage resistance tests, significantly enhancing the product's safety, reliability, and user experience.

[0022] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0024] Figure 1 This is a schematic diagram of the structural hierarchy of the three-dimensional curved integrated transparent heating mask in the embodiment of the present application.

[0025] Figure 2 It is a schematic diagram of the overall structure of the three-dimensional curved integrated transparent heating mask in the embodiment of the present application.

[0026] Explanation of the accompanying drawings: 1. Rigid transparent substrate; 2. Transparent conductive heating layer; 3. Electrode; 4. Insulating protective layer; 5. Glasses leg; 6. Nose pad; 7. Mask body. DETAILED DESCRIPTION

[0027] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0028] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0029] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0030] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0031] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0032] This application provides a three-dimensional curved integrated transparent heating mask, the overall structure of which can be seen in Figure 1 and Figure 2 . The heating mask mainly includes a mask body 7, as well as glasses legs 5 and nose pads 6. The mask body 7 is sequentially stacked from the inside to the outside with: a rigid transparent substrate 1, a transparent conductive heating layer 2, an electrode 3 and an insulating protective layer 4. Among them, the transparent conductive heating layer 2 is directly grown on the three-dimensional curved surface of the rigid transparent substrate 1, and the two form an interface-free, integrated composite structure. The rigid transparent substrate 1 has a three-dimensional curved surface shape that adapts to the human face, which is divided into a concave surface for fitting the face and a convex surface away from the face. The transparent conductive heating layer 2 is arranged on the convex surface. Preferably, the glasses legs 5 and the nose pads 6 can be detachably connected to the mask body 7 by means of connecting buckles. The part of the nose pad 6 that contacts the skin can be provided with a silicone pad to play a buffering and anti-slip role.

[0033] The heating mask described in this application has electrodes 3 arranged at the upper and lower ends of the transparent conductive heating layer 2 and connected to an external adjustable temperature control power supply module. The adjustable temperature control power supply module includes a temperature sensing unit and a thermostat. The temperature sensing unit is a negative temperature coefficient (NTC) thermistor, which is mounted on the heating area on the concave side of the mask body 7. The thermostat is electrically connected to the NTC thermistor and is used to control the heating temperature and heating time of the entire heated mask. Its temperature adjustment range is between 30-50 degrees. Its working principle is: after the set temperature (for example, 45 degrees), if the actual temperature monitored by the NTC thermistor reaches 45 degrees, its test data will be transmitted back to the thermostat, and the thermostat will cut off the power supply and stop heating; when the temperature is lower than 45 degrees, the thermostat will restart heating. Preferably, this heated mask can also be designed with a battery module electrically connected to the thermostat. When the battery is fully charged, it can independently power the mask without relying on an external power source.

[0034] The present application also provides a method for preparing the heating mask, which abandons the traditional technical route of "flat film formation and then curved surface bonding" and instead adopts physical vapor deposition to directly deposit a functional thin film on an already formed three-dimensional rigid transparent substrate.

[0035] Example 1 (end point value: thin substrate / thin ITO film)

[0036] Preparation process:

[0037] 1. Substrate Preparation and Pretreatment: A 0.5 mm thick PET material was prepared into a rigid transparent substrate 1 via a hot press molding process. Pretreatment was then performed by ultrasonically cleaning the substrate in a 5% NaOH solution at 50°C for 5 minutes, followed by ultrasonic cleaning in acetone for 10 minutes, and finally, argon plasma treatment (100 W, 5 minutes).

[0038] 2. Preparation of a Transparent Conductive Heating Layer: The treated substrate was placed in a planetary rotating magnetron sputtering apparatus (substrate rotation at 10 rpm + orbital revolution at 2 rpm) and magnetron sputtered with ITO. The process parameters were: ITO target, power of 120 W, target-substrate distance of 80 mm, Ar / O2 flow ratio of 140:3, operating pressure below 1E-3 Pa, substrate temperature of 70°C, and sputtering time of 20-25 minutes, preferably 25 minutes, to obtain a transparent conductive heating layer 2 with a thickness of 10 nm.

[0039] 3. Electrode preparation: Silver paste is printed on the heating layer 2 by screen printing technology and cured at 140°C for 30 minutes; then a layer of conductive copper foil tape (thickness 0.1mm, width 3mm) is applied on the cured silver paste to form electrode 3.

[0040] 4. Insulation Layer Preparation: TPU is applied to the heating layer 2 and electrodes 3 by electrostatic spraying to form a 5μm thick insulation layer 4, which is then heat-cured at 80°C for 30 minutes. Insulation layer 4 can also be made of transparent materials such as PET, UV adhesive, or polyurethane, with a thickness ranging from 5μm to 500μm and a transmittance range of 10% to 90%. All materials comply with the ISO10993-5 medical device biocompatibility standard to ensure safety and non-irritation when in contact with the skin.

[0041] Performance testing:

[0042] Light transmittance (550nm): 85% (ASTM D1003);

[0043] Square resistance: 300Ω / □ (four-probe method);

[0044] Temperature uniformity: 42±0.5℃ (ΔT=1.0℃, infrared thermal imaging).

[0045] Example 2 (intermediate value: typical application)

[0046] Preparation process:

[0047] 1. Substrate Preparation and Pretreatment: A 2 mm thick PC material was injection molded into a rigid transparent substrate 1. Pretreatment was then performed by ultrasonic cleaning in a 5% NaOH solution at 50°C for 5 minutes, followed by plasma cleaning (150W, 10 minutes).

[0048] 2. Preparation of a Transparent Conductive Heating Layer: The treated substrate was placed in a planetary rotating magnetron sputtering device and magnetron sputtered with ITO. The process parameters were: power 250W, Ar / O2 flow ratio 140:3, operating pressure 5Pa, substrate temperature 70°C, and sputtering time 40 minutes, resulting in a transparent conductive heating layer 2 with a thickness of 200nm.

[0049] 3. Electrode preparation: The electrode process is the same as in Example 1.

[0050] 4. Preparation of insulation layer: Apply UV glue (100μm) by spraying, and use 365nm ultraviolet light at 1000mJ / cm 2 The insulating layer 4 is solidified by applying energy of 100 nm.

[0051] Performance testing:

[0052] Light transmittance: 82%

[0053] Square resistance: 50Ω / □

[0054] Constant temperature stability: 42±0.3℃ (fluctuation ≤0.5℃ within 10min)

[0055] Example 3 (end point value: thick substrate / thick ITO film)

[0056] Preparation process:

[0057] 1. Substrate preparation and pretreatment: A 5 mm thick PMMA material was prepared into a rigid transparent substrate 1 by injection molding. This was followed by ultrasonic cleaning and plasma activation.

[0058] 2. Preparation of a Transparent Conductive Heating Layer: The treated substrate was placed in a planetary rotating magnetron sputtering device and magnetron sputtered with ITO. The process parameters were: power 120W, Ar / O2 flow ratio 140:3, operating pressure 5Pa, substrate temperature 70°C, and sputtering time 55 minutes, resulting in a transparent conductive heating layer 2 with a thickness of 500nm.

[0059] 3. Electrode preparation: The electrode process is the same as in Example 1.

[0060] 4. Preparation of insulation layer: Polyurethane (500 μm) was applied by dip coating and thermally cured at 100° C. for 1 hour to form insulation layer 4.

[0061] Performance testing:

[0062] Light transmittance: 75%

[0063] Square resistance: 10Ω / □

[0064] Mechanical strength: >50MPa (three-point bending test, ISO178)

[0065] Comparative Example 1 (Traditional Resistance Wire Mask)

[0066] Preparation: A 0.2mm diameter nickel-chromium resistance wire is embedded in a silicone base in a serpentine pattern and covered with cotton cloth. There is no transparent design. The defect analysis is shown in the following table:

[0067] Test items result Temperature uniformity Local hot spot > 50°C, ΔT = 15°C Light transmittance 0% (completely blocked) Security Exposure of the resistor wire leads to leakage risk

[0068] Comparative Example 2 (Flexible ITO bonded to a hard substrate)

[0069] Preparation: Take the same 2mm thick PC substrate as in Example 2 and attach a prefabricated flexible ITO film (200nm) to it using OCA optical adhesive (thickness 100μm). The subsequent electrode and insulation layer processes are the same. Defect analysis is shown in the following table:

[0070]

[0071] Experimental data and effect verification:

[0072] 1. Temperature uniformity test

[0073] Methods: An infrared thermal imager (FLIRT540) was used to capture the surface temperature distribution after stable operation for 10 minutes at an input voltage of 5V and a target temperature of 42℃. The maximum temperature Tmax, minimum temperature Tmin, average temperature Tavg and temperature difference ΔT = Tmax-Tmin of the entire area were calculated.

[0074] Example Tmax(℃) Tmin(℃) Tavg(℃) ΔT(℃) 1 42.5 41.5 42.0 1.0 2 42.3 41.7 42.0 0.6 3 42.8 41.6 42.2 1.2

[0075] Conclusion: Within the wide parameter range of 0.5-5mm substrate thickness and 10-500nm ITO film thickness, ΔT is ≤1.2℃, proving that the direct film deposition process of magnetron sputtering on three-dimensional curved surfaces can achieve ultra-uniform heating.

[0076] 2. Heating and constant temperature performance test

[0077] Method: Turn on the power at room temperature (25℃), record the time it takes to heat up to 42℃ and the fluctuation value of constant temperature for 10 minutes.

[0078] Example Heating time (s) Constant temperature fluctuation (±℃) 1 110 ≤0.5 2 95 ≤0.3 3 130 ≤0.8

[0079] Conclusion: The constant temperature fluctuation is ≤±0.8℃ under all parameter combinations. Safe and accurate temperature control can be achieved by combining with the adjustable power module.

[0080] 3. Optical performance test method: The optical performance of the mask is tested. The specific method is: according to the ASTM D1003 standard, the average light transmittance and haze in the visible light wavelength range of 400-700nm are measured using a spectrophotometer.

[0081] Example Light transmittance (%) Haze (%) 1 89 1.2 2 82 1.5 3 75 2.0

[0082] Conclusion: Light transmittance ≥ 75%, haze ≤ 2.0%, meeting the requirements of unobstructed vision.

[0083] 4. Reliability and safety test (taking Example 2 as an example)

[0084] Test items Example 2 Verification Standards Bending strength 78MPa ISO178 High and low temperature cycle No delamination / crack (100 cycles) 25—60℃ Square resistance change rate ≤3% (100h continuous operation) Four-probe method Cytotoxicity test Cell survival rate>98% ISO10993-5 Hi-pot test pass IEC60601(1500V)

[0085] Conclusion: The hard substrate + integrated sputtering film formation structure has passed the mechanical, environmental stress and biological safety tests, ensuring the long-term safety and reliability of the product.

[0086] 5. Infrared absorption promotion experiment

[0087] Test Group Improved essence absorption rate Increased skin moisture content The present invention (42°C) 68％ 35％ Traditional hot compress (42°C) 41％ 22％

[0088] Conclusion: The far infrared rays generated by the heating mask of the present invention can more effectively promote the absorption of skin care products.

[0089] 6. Far-infrared emission characteristics test method: Use a Fourier transform infrared spectrometer (FTIR) to detect the infrared spectrum emitted by the mask of Example 2 under a stable working state at 42° C. and analyze its emission peak position.

[0090] Results: Test results show that the infrared emission spectrum of the face mask of Example 2 of the present invention peaks at 9.4 μm. This wavelength falls within the far-infrared "vital light wave" range (typically 4-14 μm), which is beneficial to the human body. It closely matches the resonant absorption peak of water molecules in the skin, with a matching degree of up to 92% (see J. Biomed. Opt. 2017). Conclusion: The face mask of this invention is able to emit far-infrared rays of a specific wavelength, which is the physical basis for its ability to effectively enhance the absorption of skincare products (as demonstrated by infrared absorption enhancement experiments).

[0091] In summary, the present invention, with its integrated structure, ensures highly uniform and stable facial heating. When used in conjunction with a temperature control module, it enables safe, comfortable, and adjustable constant-temperature hot compresses. Furthermore, the specific wavelength of far-infrared light emitted by the heated mask during operation effectively expands pores and enhances blood circulation through a gentle thermal effect, significantly improving the skin's absorption of skincare essences. Experimental results have shown that this can increase essence absorption by 68%.

[0092] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for preparing a three-dimensional curved integrated transparent heating mask, characterized in that: The following steps are involved: Prepare a rigid transparent substrate having a three-dimensional curved surface, wherein the three-dimensional curved surface includes a convex surface and a concave surface; performing plasma activation treatment on the rigid transparent substrate; A planetary rotating magnetron sputtering process is used to directly deposit a transparent conductive heating layer on the convex surface of the rigid transparent substrate that has been subjected to plasma activation treatment, so that the transparent conductive heating layer and the rigid transparent substrate form an integrated structure.

2. The method according to claim 1, characterized in that The step of preparing a rigid transparent substrate with a three-dimensional curved surface includes: using an injection molding process or a hot pressing molding process to process a transparent polymer material into the rigid transparent substrate.

3. The method according to claim 1, characterized in that The material of the rigid transparent substrate is one of polycarbonate, polymethyl methacrylate or polyethylene terephthalate.

4. The method according to claim 1, wherein The material of the transparent conductive heating layer is transparent conductive oxide.

5. The method according to claim 4, characterized in that The transparent conductive oxide is one or more of indium tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, indium molybdenum oxide or gallium-doped zinc oxide.

6. The method according to claim 1, characterized in that The method further includes forming an electrode on the transparent conductive heating layer. The electrode forming step includes screen printing a conductive silver paste at a preset position of the transparent conductive heating layer and curing the conductive silver paste.

7. The method according to claim 6, characterized in that After curing the conductive silver paste, the method further includes pasting a layer of conductive copper foil tape on the cured conductive silver paste, wherein the thickness of the conductive copper foil tape ranges from 0.05 mm to 0.2 mm and the width ranges from 2 mm to 5 mm.

8. The method according to claim 1, characterized in that The method further includes forming a transparent insulating protective layer on the transparent conductive heating layer. The forming step includes coating a layer of transparent insulating material on the transparent conductive heating layer and curing the transparent insulating material.

9. The method according to claim 8, characterized in that The curing step is to use ultraviolet light for curing, and the wavelength range of the ultraviolet light is 360nm to 370nm, and the range of irradiation energy is 900mJ / cm 2 Up to 1100mJ / cm 2 .

10. A three-dimensional curved integrated transparent heating mask prepared by the method according to any one of claims 1 to 9.

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