Heating sheet

Abstract

The invention provides a heating sheet. The heating sheet comprises a heating part and electrodes connected to the two opposite sides of the heating part respectively. The average thickness of the heating part in unit distance is gradually reduced from the middle to the direction close to the electrode, and the unit distance is larger than or equal to 100 micrometers. The heating of the heating sheet follows the Joule heating effect, and the heating part has the characteristic that the average thickness per unit distance is gradually reduced from the middle part to the two sides, so that the resistance per unit distance of the heating part has the trend of gradually increasing from the middle part to the two sides, and the heating power of the heating part also shows the characteristic of gradually increasing from the middle part to the two sides. Therefore, the problem of non-uniform temperature distribution caused by heat dissipation capability differences of different areas of the heating part can be reduced, actual heat loss is effectively counteracted, the actual temperature distribution of the surface of the heating part is more uniform, and then the effective atomization area proportion is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of heating sheet processing, and in particular relates to a heating sheet. Background Art

[0002] The heating plate is an important part of the atomizer. If the temperature of the heating plate is too low, the atomization effect may deteriorate. If the temperature is too high, part of the smoke oil may become charred, thus affecting the user experience. In the related technology, the thickness of each area of ​​the heating plate is usually fixed. When the current flows through the heating plate, the heat in the middle area of ​​the heating plate can only be dissipated by heat conduction and phase change on the upper and lower surfaces. In addition to the heat from the upper and lower surfaces, the heat in the edge area can also be dissipated from the electrodes and pins with lower temperatures around it, making the temperature of the edge area of ​​the heating plate low and the temperature of the middle area high, that is, the temperature distribution of the heating plate is uneven; which leads to the temperature of the middle area reaching the critical value faster during the power increase process, and the smoke has a burnt smell, and even the heating plate is burned, and the atomization effect is not ideal. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a heating plate, aiming to solve the problem of uneven temperature distribution of the heating plate in the related art.

[0004] To solve the above technical problems, the present invention is implemented as follows: a heating sheet is provided, comprising: a heating part and electrodes respectively connected to opposite sides of the heating part; the average thickness per unit distance of the heating part gradually decreases from the middle toward the direction close to the electrodes, and the unit distance is greater than or equal to 100um. Furthermore, at least one surface of the heating portion is formed with an undulating concave-convex structure.

[0005] Furthermore, the top surface and the bottom surface of the heating portion are parallel.

[0006] Further, the distance between the top surface and the bottom surface is 0.05-0.15 mm.

[0007] Furthermore, at least one surface of the heating portion is provided with a groove.

[0008] Furthermore, the arrangement density of the grooves on the surface of the heating portion gradually increases from the middle of the surface of the heating portion toward the direction close to the electrode.

[0009] Furthermore, the depth of the groove gradually increases from the middle of the surface of the heating portion toward the electrode.

[0010] Furthermore, the depth of the groove on the heating part ranges from 5 to 40 um.

[0011] Furthermore, at least one surface of the heating portion is provided with grooves arranged at intervals or distributed in a mesh shape.

[0012] Furthermore, the shape of the groove is at least one of a circle, an ellipse, a polygon, a strip, a curve, and a broken line.

[0013] Furthermore, a plurality of long strip grooves are arranged at intervals on one surface of the heating portion.

[0014] Furthermore, the spacing between adjacent grooves is 60-300 um, and the spacing between adjacent grooves is smaller than the unit distance.

[0015] Furthermore, the distance between the top surface and the bottom surface of the heating portion gradually decreases from the middle portion toward the electrode.

[0016] Compared with the prior art, the heat generating sheet of the present invention has the following beneficial effects: considering that the heat dissipation capacity of each area of ​​the heat generating part generally tends to increase gradually from the middle to the edge, when preparing the heat generating sheet, the average thickness per unit distance of the edge area of ​​the heat generating part is gradually decreased from the middle to both sides, and the resistance control is achieved by thickness control, so that the resistance per unit distance of the heat generating part tends to increase gradually from the middle to both sides, so that the heat generating power of the heat generating part shows the characteristic of gradually increasing from the middle to the edge, thereby reducing the temperature distribution difference of different areas of the heat generating part, effectively offsetting the actual heat loss, making the actual temperature distribution on the surface of the heat generating part more uniform, and thereby increasing the effective atomization area ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a metal heating sheet in an embodiment of the present invention; Figure 2 This is a process flow chart of the heating sheet in the embodiment of the present invention; Figure 3 is a schematic cross-sectional view parallel to the current direction of a heating sheet in an embodiment of the present invention; Figure 4 is a schematic diagram of etching electrodes in the first etching processing method in an embodiment of the present invention and a diagram showing changes in electrode movement speed over time during the etching process; Figure 5 is a schematic diagram of an etching electrode in a second etching processing method in an embodiment of the present invention; Figure 6 It is a schematic diagram of an etching electrode in a third etching processing method in an embodiment of the present invention.

[0018] Among them, Figure 1 The symbols in the figure indicate: 01, heating part; 02, electrode. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] like Figure 1 As shown, in this embodiment, the heating sheet includes: a heating portion 01 and electrodes 02 respectively connected to opposite sides of the heating portion 01; the average thickness per unit distance of the heating portion 01 gradually decreases from the middle toward the electrode 02, and the unit distance is greater than or equal to 100um.

[0021] Specifically, the unit distance can be 100 um, 110 um, 120 um, etc., preferably 100 um. In this embodiment, the heating of the heating sheet conforms to the Joule heating effect, and the heating portion 01 has the characteristic that the average thickness per unit distance gradually decreases from the middle to both sides, that is, the average thickness per unit distance in the B region is less than the average thickness per unit distance in the A region. The resistance per unit distance of the heating portion 01 has a trend of gradually increasing from the middle to both sides, so that the heating power of the heating portion 01 also shows a characteristic of gradually increasing from the middle to both sides, which can reduce the problem of uneven temperature distribution caused by the difference in heat dissipation capacity of different regions of the heating portion 01, effectively offset the actual heat loss, and make the actual temperature distribution on the surface of the heating portion 01 more uniform, thereby increasing the proportion of effective atomization area.

[0022] In the present embodiment, the heating part 01 is a heating wire, and the shape of the heating wire can be at least one of a polygon, an S-shape, a flat fold line, a butterfly-wing shape, a flat wave shape, a flat sawtooth shape, a flat spiral shape, and a circle. The cross-sectional width of the heating wire is 0.01-1mm. Preferably, the cross-sectional width of the heating wire is set to 0.08mm, and the width refers to the cross-sectional thickness in the horizontal direction. The heating wire includes at least two heating segments connected between the two electrodes 02 and spaced apart and a supporting segment connected between two adjacent heating segments. The heating sheet also includes a pin connected to the outermost heating segment and extending outward, and the pin can play a role of fixing and heat conduction.

[0023] In some embodiments, the heating section can be two sections, or three sections or more. The heating portion 01 has two heating sections, both of which are plane fold lines and parallel to each other, and the turning points of the heating sections protruding toward the outside of the heating portion 01 are connected to the pins respectively. The heating wire can be prepared by stamping a metal sheet using a preset template. When the heating sheet is working, the heat generated by the outside of the heating portion 01 can be derived from the surface of the heating portion 01, the electrode 02 and the pin, and the pin and the electrode 02 are both connected to the outside of the heating portion 01, and the area near the electrode 02 and the area near the pin in the heating portion 01 have strong heat dissipation capacity. Of course, in some other embodiments, the heating wire can also be obtained by combining multiple shapes, for example: a combination of a plane wavy shape and a circular shape. The width of different parts of the heating wire can be the same or different, for example: the width of the heating wire in the middle area of ​​the heating portion 01 is larger, and the width of the edge area is smaller, thereby, it can also achieve the effect of improving the uniformity of the temperature distribution of the heating portion 01 to a certain extent.

[0024] In this embodiment, at least one surface of the heating part 01 is formed with an undulating concave-convex structure, so that the heating part 01 has a larger heat-conducting contact area, the surface temperature is enhanced, and when it is attached to the oil-conducting body, the smoke oil adsorption efficiency is improved, and the atomization effect can also be improved. The top and bottom surfaces of the heating part 01 are parallel, which is convenient for installation. The resistance change of a heating sheet that is too thin or too thick is not obvious. Therefore, in this embodiment, the distance between the top and bottom surfaces can be 0.05-0.15mm, preferably 0.07mm.

[0025] Furthermore, if Figure 1 The structure corresponding to the middle a part, in this embodiment, can be provided with grooves on the surface of the heating part 01, and a concave-convex surface is formed by the groove structure to increase the surface area of ​​the heating part 01. Specifically, a groove is provided on at least one surface of the heating part 01. The arrangement density of the grooves on the surface of the heating part 01 gradually increases from the middle of the surface of the heating part 01 to the direction close to the electrode 02. The depth of the groove gradually increases from the middle of the surface of the heating part 01 to the direction close to the electrode 02. The depth range of the groove on the heating part 01 is 5-40um. A plurality of long strip grooves are arranged at intervals on one surface of the heating part 01. The spacing between adjacent grooves is 60-300um, and the spacing between adjacent grooves is less than the unit distance. It should be noted that in this embodiment, the shape setting of the heating wire does not conflict with the shape, arrangement position and other settings of the grooves. The grooves are distributed on the surface of the heating wire, and the shape of the heating wire can be multiple choices.

[0026] In some embodiments, a groove is provided on one of the surfaces of the heating part 01 to form the required concave-convex structure and increase the thermal contact area. Of course, grooves can also be provided on both surfaces of the heating part 01. The depth and arrangement of the grooves are set according to actual needs and are not limited here. The grooves can be prepared by etching. Of course, in some other embodiments, a rough surface can also be obtained by sandblasting, chemical etching, etc., so as to increase the thermal contact area.

[0027] In some embodiments, the groove depths of each region of the heating portion 01 are the same, and the arrangement density of the grooves on the surface of the heating portion 01 is controlled to gradually increase from the middle of the surface of the heating portion 01 toward the direction close to the electrode 02. The arrangement of the grooves in the middle region of the heating portion 01 is made more sparse, and the arrangement of the grooves in the edge region is made more dense, so that the average thickness per unit distance of the heating portion 01 has the characteristic of gradually decreasing from the middle to the direction close to the electrode 02, and the heating power of the heating portion 01 also shows the characteristic of gradually increasing from the middle of the heating portion 01 toward the direction close to the electrode 02.

[0028] In some embodiments, the grooves on the surface of the heating part 01 can also be arranged in a form in which the depth gradually increases from the middle of the surface of the heating part 01 toward the direction close to the electrode 02, so that the average thickness per unit distance of the heating part 01 gradually decreases from the middle to the direction close to the electrode 02, so that the heating power of the heating part 01 also shows the characteristic of gradually increasing from the middle of the heating part 01 toward the direction close to the electrode 02. The depth of the grooves in the entire heating part 01 varies from 10 um to 20 um from the middle to both sides.

[0029] It is understandable that in this embodiment, the average thickness per unit distance of the heating part 01 can be controlled by controlling the arrangement density of the grooves in each area of ​​the heating part 01, or the average thickness per unit distance of the heating part 01 can be controlled by only controlling the depth of the grooves in each area, and the groove structure on the surface of the heating part 01 can be set in combination with these two methods. In addition, the grooves on the heating part 01 can also be set in a form in which the arrangement density gradually increases from the middle of the surface of the heating part 01 to the surroundings, and / or the depth gradually increases from the middle of the surface of the heating part 01 to the surroundings.

[0030] In the present embodiment, at least one surface of the heating portion 01 is provided with grooves arranged at intervals or distributed in a mesh. The shape of the groove is at least one of a circle, an ellipse, a polygon, a strip, a curve, and a broken line. Regardless of whether the grooves are arranged at intervals or distributed in a mesh, the shape of the grooves can be one or more combinations of a circle, an ellipse, a polygon, a strip, a curve, and a broken line. It should be noted that when a plurality of grooves arranged at intervals are provided on the surface of the heating portion 01, the spacing between adjacent grooves can be the same or different. Of course, in some other embodiments, the grooves can also be irregular shapes, as long as it is ensured that the arrangement depth (or arrangement density) per unit distance in the heating portion 01 has a regular characteristic of gradually increasing from the center to the direction close to the electrode 02, and no limitation is made here.

[0031] like Figure 1 As shown, in a specific implementation of this embodiment, a plurality of long strip grooves are arranged at intervals on one surface of the heating portion 01, the grooves are parallel to each other, and the spacing between adjacent grooves is equal, and the grooves on the surface of the heating portion 01 are arranged so that the depth gradually increases from the middle of the surface of the heating portion 01 toward the direction close to the electrode 02; Figure 1 The parts marked a in the A area and the B area are all etched parts, and the parts marked b in the A area and the B area are all unetched parts. The distance from the bottom of the groove in the A area to the bottom side of the heating part is d1, and the distance from the bottom of the groove in the B area to the bottom side of the heating part is d2. , so that the groove depth in area B is greater than the groove depth in area A, and the length extension direction of the groove can be perpendicular to the direction in which the groove depth in the heating part 01 increases (or decreases). The number of grooves is preferably 20, and of course it can also be 18, 25, 30, etc., which can be determined according to parameters such as the width and thickness of the actual heating part 01, and is not limited here. The depth variation law of each groove arranged in sequence can be followed by first decreasing one by one and then increasing one by one; the depth variation law of each groove arranged in sequence can also be followed by first decreasing in a step-by-step manner and then increasing in a step-by-step manner, and each step is in units of two or three grooves. The spacing between adjacent grooves is less than the above-mentioned "unit distance"; the spacing between adjacent grooves can be 100um, 110um, 120um, etc., preferably, 100um.

[0032] In another specific implementation of this embodiment, the groove can be a mesh groove formed by interlacing and connecting a plurality of long strip grooves. The shape of the grooves connected as one can be a diamond mesh or a triangular mesh, etc. The arrangement density of the grids formed by the grooves in various areas of the surface of the heating part 01 is equal, and the depth of the mesh grooves in the middle area increases from the middle to the two sides close to the electrode 02. The depth of the grooves in the entire heating part 01 varies from the middle to the two sides in a range of 10 um to 20um.

[0033] It should be noted that, in this embodiment, the specific parameters such as the ranges and sizes involved in the above-mentioned embodiments are only exemplary, intended to analyze and illustrate the present invention, and cannot be understood as limitations of the present invention. In this embodiment, for the scheme of controlling the average thickness per unit distance by setting grooves, multiple sets of parallel implementation schemes are included, and the setting of the grooves can simultaneously have the above-mentioned shape, quantity, arrangement form, depth adjustment law, arrangement density law and other corresponding technical features, or only have some of the technical features.

[0034] In one implementation of the present embodiment, the distance between the top surface and the bottom surface of the heating part 01 gradually decreases from the middle to the direction close to the electrode 02. Among them, the substrate sheet used to prepare the heating part 01 is a metal sheet that is thick in the middle and thin on both sides, and a concave-convex structure is formed on the top surface and / or the bottom surface of the metal sheet, so that the heating part 01 has at least one rough surface. That is, the metal sheet has a rough surface, and its rough surface can be processed by chemical etching, sandblasting, grinding, etc.; so that after the metal sheet is stamped and formed into a heating sheet, the top surface and / or the bottom surface of the heating part 01 also has a concave-convex structure. The heating part 01 with a concave-convex structure on the surface has a larger heat exchange area than the heating part 01 with a smooth surface, and the surface temperature of the heating part 01 is enhanced, which improves the smoke oil adsorption efficiency of the heating wire to a certain extent, and the atomization effect is also improved to a certain extent.

[0035] The processing method of the heating sheet includes the following steps: S100, providing a substrate sheet, and pre-treating the substrate sheet to obtain an intermediate body whose average thickness per unit distance gradually decreases from the middle to both sides.

[0036] Specifically, the unit distance is greater than or equal to 100um. The heating sheet includes a heating portion and electrodes connected to opposite sides of the heating portion, the middle of the intermediate body corresponds to the middle of the heating portion, and the direction of the middle of the heating portion toward the electrode is the same as the direction in which the average thickness of the intermediate body decreases. In this embodiment, an intermediate body is prepared whose average thickness per unit distance gradually decreases from the middle to both sides.

[0037] S200, removing excess material in the intermediate to obtain a heating sheet of a target shape. Specifically, the required heating sheet can be obtained by removing the material at the corresponding position in the intermediate body according to the required shape of the heating sheet, and the heating portion of the heating sheet also has the characteristic that the average thickness per unit distance gradually decreases from the middle to the two sides, so that the heating power of the heating portion gradually increases from the middle to the edge. Since the heat dissipation capacity of each area in the heating portion has a trend of gradually increasing from the middle to the edge, it can be achieved that the area with strong heat dissipation capacity of the heating portion has a larger heating power, and the area with weak heat dissipation capacity has a smaller heating power, thereby reducing the temperature distribution difference in different areas of the heating portion, and can effectively offset the actual heat loss, so that the actual temperature distribution on the surface of the heating portion is more uniform, and the effective atomization area ratio of the heating sheet is increased. Among them, step S200 includes: using a stamping template to stamp the intermediate body to obtain the required heating sheet sample.

[0038] like Figure 3 The figure shows a cross-sectional schematic diagram of a heating sheet formed by step S100 and step S200 in the present embodiment, wherein the heating sheet includes a plurality of heating areas of unit distance, and the surface of each heating area of ​​unit distance includes a plurality of grooves formed by etching, and the groove depth of the heating area of ​​the middle unit distance gradually increases toward the groove depth of the unit distance on both sides, and the heating areas of unit distance at both ends are symmetrical about the heating area of ​​the middle unit distance. Specifically, the resistance of the heating area from the positive electrode connection end to the negative electrode connection end is set to R1, R2, R3, R2, and R1 in sequence, and each heating area forms a series circuit. The actual current path passing through R1, R2, and R3 is the unetched part of each heating area, which is the basic heating area of ​​the heating area of ​​unit distance. The etched part of the area generates less heat, such as Figure 3 The circled part, that is, the unetched metal around the etching area is short-circuited, so it only conducts heat but does not generate heat. That is to say, the heating area per unit distance after etching in step S100 and step S200 includes a heat-conducting part and a heat-generating part, and the etching groove is formed in the gap of the heat-conducting part. The heat-generating parts of the heating areas per unit distance are connected in series.

[0039] In a specific embodiment, at room temperature (20 degrees Celsius), the resistivity of the heating sheet is ρ is 0.74Ω / mm2*m (20℃) When the heating power of each area of ​​the heating part is characterized by the series equivalent resistance, the heating of the metal heating sheet conforms to the Joule heating effect of the conductor. According to the resistivity formula and the Joule heat formula It can be seen that the heat generated per unit length of the heating part is equal to: Among them, q is the heat generated by the heating part per unit length; ρ is the resistivity, which is related to the material and temperature; W is the actual width of the heating area, δ is the actual heating thickness of the heating sheet per unit length, and I is the current passing through each heating area.

[0040] The calculation formula for the equivalent R resistance is: Combination Figure 3 In a specific implementation of this embodiment, ρ is 0.74Ω / mm 2 *m (20℃), take the etching spacing l as 100um, the width of the heating section w in the heating part as 1mm, the overall thickness of the heating part as 0.08mm, the etching depth corresponding to R3 is 10um, δ3 is 0.07mm; the etching depth corresponding to R1 is 20um, δ1 is 0.06mm; the calculation results are: The corresponding area has the largest average thickness and the smallest equivalent resistance. The average thickness of the corresponding area is the smallest and the equivalent resistance is the largest. That is, the larger the thickness, the smaller the equivalent resistance. When the same current flows through the equivalent series circuit, the larger the thickness, the smaller the heat generated. It can be calculated that the resistance variation range from the middle of the heating part to both sides is 16.7%.

[0041] Since the heating element is connected in series from the edge to the center, combined with the unit length resistance heat formula: , we can calculate and The heat value ratio: That is, the heat per unit length of the central area of ​​the heating part is 85.72% of the heat per unit length of the outer area. Therefore, the heat generation in the middle area of ​​the heating part is small and the heat dissipation capacity is low, while the heat generation in the edge area is large and the heat dissipation capacity is good, which can effectively solve the problem of uneven temperature distribution caused by the difference in heat dissipation capacity of different areas, thereby improving the uniformity of temperature distribution in various areas of the heating part. In this embodiment, the above parameters are only exemplary and cannot be understood as limitations of the present invention.

[0042] In this embodiment, Figure 2101 represents a metal sheet, 102 represents a groove pattern formed on the surface of the intermediate, 103 represents a heating part, 104 represents an electrode, and 105 is a pin. When the heating sheet is working, current flows between the two electrodes. The substrate sheet can be a metal sheet or a non-metal sheet. The substrate sheet is a metal sheet, and the metal sheet can be a metal such as iron, chromium, aluminum, or a related alloy sheet. The top surface and the bottom surface of the metal sheet are parallel, and the resistance change of the heating sheet that is too thin or too thick is not obvious. Therefore, the distance between the top surface and the bottom surface can be 0.05-0.15mm, preferably 0.07mm. In this embodiment, a groove can be opened on the surface of the metal sheet.

[0043] In the above step S100, the pretreatment process includes: etching the metal sheet to obtain an intermediate having an undulating concave-convex structure on the surface; wherein the depth of the grooves on the intermediate gradually increases from the middle to both sides. Specifically, the process of etching the metal sheet includes: single-sided etching of the metal sheet, or double-sided etching of the metal sheet. Preferably, single-sided etching is performed. The etching method can be one of chemical etching, electrolytic etching, laser etching, and ultrasonic etching. In this embodiment, electrolytic etching is preferably used for pretreatment, which is simple to operate and low in cost.

[0044] Specifically, step S100 includes: S101, covering the area on the metal sheet surface that does not need to be etched with a resist to obtain a covering body with the area to be etched; wherein the area to be etched is the area on the metal sheet surface that is not covered by the resist. S102, etching the area to be etched, and controlling the etching amount per unit distance of the etching area to gradually increase from the middle of the area to be etched to both sides; removing the remaining resist on the metal sheet to obtain an intermediate.

[0045] More specifically, the above step S102 includes: etching the area to be etched using one of ferric chloride etching solution, ammonium persulfate etching solution, sulfuric acid / chromic acid etching solution, and sulfuric acid / hydrogen peroxide etching solution. In this embodiment, FeCl3+HCl solution is preferably used to etch the area to be etched.

[0046] Further, in this embodiment, the above step S101 includes: S1011, coating a resist on the metal sheet and drying it; wherein the resist is one of UV photoresist, screen printing ink, and laser ink; S1012, exposing and developing the metal sheet coated with the resist to obtain a covering body. Specifically, before coating the resist, the metal sheet needs to be cleaned to remove dirt, dust, etc. on the surface of the material. Then, further exposure and development operations are performed according to actual needs.

[0047] Furthermore, in this embodiment, step S1012 includes: performing patterned exposure on the to-be-etched surface of the metal sheet coated with the resist, so that the unexposed area on the to-be-etched surface is displayed as a target etching pattern; wherein the target etching pattern is at least one of a circle, an ellipse, a polygon, a strip, a curve, and a broken line, and the target etching pattern is arranged at intervals or in a mesh shape; using a preset chemical reagent to wash away the resist in the unexposed area to obtain a covering body. Preferably, UV glue is used as the resist of this embodiment, and the target etching pattern can be set as a strip pattern arranged at intervals.

[0048] In this embodiment, the following three specific etching processes are provided: In the first implementation of this embodiment, the above-mentioned step S102 includes: S1021a, fixing the covering body on the anode of the mobile electrolytic etching device, and making the area to be etched face the cathode of the mobile electrolytic etching device; S1022a, turning on the etching so that the depth of the groove formed on the surface to be etched gradually increases from the middle to both sides, and obtaining a groove corresponding to the target etching pattern shape.

[0049] In this embodiment, step S1022a further includes: when the amount of current is the same, adjusting the moving speed of the cathode to adjust the etching depth of different areas, so as to obtain a groove corresponding to the target etching pattern shape.

[0050] Specifically, Figure 4 As shown, the movable cathode electrode can move on a plane parallel to the anode. During the etching cycle, the negative electrode is controlled to move at a non-uniform speed on a plane parallel to the positive electrode plate; the etching amount is also the amount of material removed from the metal sheet. Where the negative electrode moves at a lower speed, the relative etching time of the position will increase, and the etching amount will also increase accordingly, so that the depth of the grooves at different positions in the area to be etched can be controlled. In this embodiment, the moving speed of the cathode electrode in the area to be etched is controlled to gradually decrease from the middle position to both sides. After a complete etching cycle, the grooves formed on the surface of the metal sheet show a trend of gradually increasing depth from both sides to the middle. Considering that when preparing the heating sheet, some pins will be set on its outside, and the pins also have thermal conductivity, therefore, during the etching process, the moving speed of the cathode electrode can be controlled to gradually decrease from the middle to the surroundings, so that the grooves formed in the area to be etched have a trend of gradually increasing depth from the middle to the surroundings.

[0051] In a second implementation of the present embodiment, the electrode used to etch the metal sheet includes an anode and a cathode, the side of the anode close to the cathode is a plane, and the distance between the cathodes gradually decreases from the middle to the sides; the above-mentioned step S102 includes: fixing the exposed and developed metal sheet between the anode and the cathode, and making the area to be etched face the middle of the side of the cathode close to the anode; electrifying the electrode for etching to obtain a groove corresponding to the shape of the target etching pattern.

[0052] Specifically, Figure 5 As shown, a negative electrode of a specific shape is customized, and the distance between different areas on the cathode and the anode is changed by changing the shape of the electrode. The current density in different areas is changed by adjusting the distance between the corresponding areas of the two electrodes, so that the groove formed in the area to be etched has a tendency to gradually increase in depth from the middle to the sides. The cathode electrode used is thin in the middle and thick on both sides, so that the distance from the cathode to the anode shows a tendency to gradually decrease from the middle to the sides. Of course, in some other embodiments, the cathode electrode can also be designed to be thin in the middle and thick at the edges, so that the distance from the cathode to the anode gradually decreases from the middle to the outside, and the groove formed in the area to be etched finally has a tendency to gradually increase in depth from the middle to the surroundings.

[0053] In a third implementation of the present embodiment, the electrode for etching the metal sheet includes an anode and at least three cathodes arranged in parallel above the anode. The above step S102 includes: fixing the exposed and developed metal sheet between the anode and the cathode; controlling each cathode to etch at the corresponding position of the area to be etched according to the preset duty cycle of the electrode, so as to obtain a groove corresponding to the shape of the target etching pattern; the duty cycle is the ratio between the power-on time of the target cathode and the sum of the power-on time of all cathodes. Among them, the duty cycles corresponding to the cathodes arranged in sequence are gradient-changed; the gradient change trend is shown as first decreasing and then increasing.

[0054] Specifically, Figure 6 As shown, the etching electrode includes a plurality of cathodes arranged at intervals above the anode, and each electrode plate can control the power-on time individually. In actual application, an etching electrode group with 11 cathodes can be used to etch the covering body, and the duty ratios of the cathodes arranged in sequence can be set to 90%, 70%, 60%, 60%, 50%, 50%, 50%, 60%, 60%, 70%, and 90%, respectively; the etching process is adjusted by adjusting the duty ratio corresponding to each cathode, and finally a groove corresponding to the target etching pattern shape is etched.

[0055] In this embodiment, the substrate sheet can be a metal substrate whose distance between the top surface and the bottom surface gradually decreases from the middle to the two sides; the pretreatment operation is at least one of chemical etching, sandblasting, and grinding. The intermediate with a rough surface is obtained through the above pretreatment operation. The heating plate formed by processing the intermediate with a rough surface also has a large heat exchange area. While ensuring the uniform temperature distribution of the heating part, the oil adsorption efficiency of the heating wire is improved to a certain extent, and the atomization effect is also improved to a certain extent.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A heating sheet, It is characterized in that It comprises a heating part and electrodes respectively connected to opposite sides of the heating part; the average thickness per unit distance of the heating part gradually decreases from the middle part toward the direction close to the electrodes; the unit distance is greater than or equal to 100um.

2. The heating sheet according to claim 1, It is characterized in that At least one surface of the heating portion is formed with an undulating concave-convex structure.

3. The heating sheet according to claim 2, It is characterized in that The top surface and the bottom surface of the heating portion are parallel.

4. The heating sheet according to claim 3, It is characterized in that The distance between the top surface and the bottom surface is 0.05-0.15 mm.

5. The heating sheet according to claim 3, It is characterized in that At least one surface of the heating portion is provided with a groove.

6. The heating sheet according to claim 5, It is characterized in that The arrangement density of the grooves on the surface of the heating portion gradually increases from the middle of the surface of the heating portion toward the direction close to the electrode.

7. The heating sheet according to claim 5, It is characterized in that The depth of the groove gradually increases from the middle of the surface of the heating portion toward the electrode.

8. The heating sheet according to claim 7, It is characterized in that The depth of the groove on the heating part ranges from 5 to 40 μm.

9. The heating sheet according to claim 6 or 7, It is characterized in that At least one surface of the heating portion is provided with grooves arranged at intervals or distributed in a mesh shape.

10. The heating sheet according to claim 5, It is characterized in that The heat generating portion comprises a heat conducting portion and a heat generating portion, the groove is formed on the heat conducting portion, and the heat generating portion is connected in series.

11. The heating sheet according to claim 7, It is characterized in that The spacing between adjacent grooves is 60-300 um, and the spacing between adjacent grooves is smaller than the unit distance.

12. The heating sheet according to claim 2, It is characterized in that The distance between the top surface and the bottom surface of the heating portion gradually decreases from the middle portion toward the electrode.

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