Preparation method of special-shaped electric heater and special-shaped flexible electric heater prepared by the method

Abstract

The application discloses a preparation method of a special-shaped electric heater and a special-shaped flexible electric heater prepared by the method. In the preparation process, first, the shape size and electric heating power of the electric heater are designed according to the use requirement. Then, an electrothermal conversion layer is deposited on the surface of a lower insulating packaging layer, the resistance value and layout mode of a heating element of the electric heater are designed, the electrothermal conversion material on the surface of the lower insulating layer is engraved into the heating element, a metal layer is deposited on the heating element by a vacuum method to serve as a power line welding point, a power line is welded on the surface of the power line welding point, and finally, a vacuum hot-pressing is adopted to package an upper insulating layer to form a complete electric heater. The application can not only arrange the layout mode of the heating element according to the requirement, but also adjust the heating resistance value of the heating element by changing the width and length of the heating element, so that the heating power of the electric heater is conveniently adjusted, a high-voltage low-current electric heater can be prepared, and the application requirement of the heater in the aerospace field is met, that is, the heater has many specifications and large size changes.

Description

Technical Field

[0001] This invention relates to the field of aerospace thermal control technology, and in particular to a method for preparing an irregularly shaped electric heater and the prepared irregularly shaped flexible electric heater. Background Technology

[0002] Electric heaters are a crucial temperature control method in the field of active thermal control for aerospace. Aerospace electric heaters typically consist of two or more layers of electrically insulating material sandwiching a single or double layer of manganese copper, manganese cupronickel, or nickel-chromium alloy heating element and lead wires. Currently, electric heaters used in the aerospace field are mostly square or rectangular. However, due to the numerous and complex structures and functions of internal spacecraft components, square or rectangular electric heaters are insufficient to meet the heating requirements of spacecraft with complex shapes. Heating elements in the aerospace field are usually made of manganese copper, manganese cupronickel, or nickel-chromium alloy wires, or chemically etched manganese copper or manganese cupronickel alloy foils. Heating elements made from these alloy materials have advantages such as a low temperature coefficient of resistance, good mechanical and heat resistance, and long service life. However, due to the low resistivity of these alloy wires or foils, the manufacturing process is complex, resulting in the ability to produce low-voltage, high-current electric heaters. Furthermore, the power adjustment of these heaters is difficult. Additionally, the high density of the alloy materials hinders spacecraft weight reduction, and the high rigidity of the alloy materials makes installation and use inconvenient. Therefore, there is an urgent need for an electric heater with variable shape and size, adjustable heating power, low material density, and good flexibility to solve the above problems. Summary of the Invention

[0003] This invention provides a method for preparing irregularly shaped flexible electric heaters, which can be used to prepare electric heaters with complex shapes, adjustable heating power, low density, good flexibility, and convenient installation and use required in the aerospace field.

[0004] The method for preparing the irregularly shaped electric heater of the present invention includes the following steps:

[0005] Step 1: Design the external dimensions and heating power of the electric heater according to actual usage requirements.

[0006] Step 2: Electrothermal conversion material is deposited on the lower insulating layer using a vacuum deposition method.

[0007] Step 3: Cut the lower insulating layer coated with electrothermal conversion material according to the design shape. The shape and size of the cut layer should be the same as the part to be heated.

[0008] Step 4: Design the resistance value and distribution of the heating element of the electric heater.

[0009] First, design the heating element of the electric heater.

[0010] The heating element is strip-shaped, and can be arranged in an S-shape or a spiral pattern, or a combination of both; the heating power conforms to P=AU.2 / (R □ ·S). Where, U is the operating voltage of the electric heater; R □ S is the sheet resistance of the heating material plated on the surface of the lower insulating encapsulation layer 4; S is the ratio of the length to the width of the strip-shaped heating element 3; A is the correction factor.

[0011] After determining the aspect ratio of the heating element, software is used to simulate the width, length, and layout of the heating element. While keeping the aspect ratio of the heating element constant, the changes in the width and length of the heating element are simulated to ensure that the heating element is evenly distributed within the heating area of ​​the electric heater.

[0012] Step 5: Based on the simulation results in Step 4, scribble the electrothermal conversion material on the surface of the cut lower insulating layer to form a heating element.

[0013] First, scribbles are made along the heating area of ​​the electric heater, and an insulation area is made around the edge of the lower insulation layer. All electrothermal conversion material in the insulation area is removed. The inside of the insulation area is the heating area, and the outside is the edge insulation area.

[0014] Subsequently, according to the length, width and layout of the heating element designed in step 4, the internal heating area is laser-etched into strip-shaped heating elements with uniform length and width; and when etching, the width of the laser etched line is no more than 150μm.

[0015] Step 6: Measure the insulation resistance of the heating element and the edge insulation area. If the insulation resistance is greater than 10kΩ, it means that the electrothermal conversion material in the edge insulation area is completely disconnected from the electrothermal conversion material in the internal heating area, and the heating element is completed.

[0016] Step 7: Deposit a metal layer on the upper surface of the head and tail of the heating element as a power line soldering point.

[0017] Step 8: Solder the power cord onto the surface of the power cord solder joint.

[0018] Step 9: Vacuum heat press encapsulation of the insulating layer to form a complete flexible electric heater.

[0019] Based on the above preparation method, an irregularly shaped flexible electric heater is obtained. The overall shape is designed according to actual use requirements, and the thickness is controlled between 20 and 500 μm. It includes an upper insulating encapsulation layer, a lower insulating encapsulation layer, a heating element, a power line soldering point, and a power line.

[0020] The upper and lower insulating encapsulation layers are identical in shape and size and are symmetrically arranged. The heating element is located between the upper and lower insulating encapsulation layers. The heating element is a strip with a width of not less than 5mm. After bending, it can be arranged in an S-shape or a spiral shape, or a combination of both. The spacing between the strips at the relative positions of the bent parts is equal. The outer contour of the heating element and the circumference of the lower insulating layer form an edge insulation area. The insulation resistance of the heating element is not less than 10kΩ.

[0021] Power line soldering points are designed at both ends of the upper surface of the heating element, located between the upper insulation layer and the heating element; the diameter of the power line soldering points is not less than 5mm, and the thickness is 50nm to 500nm; and the distance between adjacent sides of the power line soldering points at the beginning and end of the heating element is not less than 5mm.

[0022] The power cord is connected to the heating element through the power cord solder joint and is located between the upper insulating encapsulation layer and the heating element.

[0023] The advantages of this invention are:

[0024] 1) The method for preparing irregularly shaped flexible electric heaters of the present invention can cut upper and lower insulating encapsulation layers of different appearance shapes and sizes according to the application requirements, and then encapsulate them to prepare flexible electric heaters of various shapes and specifications, which are suitable for the application requirements of aerospace fields with complex structures and large changes in external dimensions.

[0025] 2) The method for preparing the irregular flexible electric heater of the present invention uses laser scribing to easily scribble the planar heating material on the surface of the insulating encapsulation layer into strip-shaped heating elements of different sizes. The layout of the heating elements can be arranged according to the requirements, which is suitable for the complex structural application requirements in the aerospace field.

[0026] 3) The method for preparing the irregular flexible electric heater of the present invention uses laser scribing to scribing the planar heating material into strip-shaped heating elements. The heating resistance value of the heating element can be adjusted by changing the sheet resistance of the heating material and the width and length of the scribing heating element. It is suitable for the application requirements of electric heaters with large variations in heating power in the aerospace field.

[0027] 4) The method for preparing the irregular flexible electric heater of the present invention adopts vacuum lamination and encapsulation of the upper and lower insulating encapsulation layers to prepare the flexible electric heater. The thickness and material of the upper and lower insulating layers can be flexibly changed according to the special requirements of the use environment, which is suitable for application fields with stringent requirements for the encapsulation material of the electric heater.

[0028] 5) The irregular flexible electric heater prepared by the method of the present invention uses oxide semiconductor thin film materials such as ITO, MZO, AZO, and TO as heating materials. The sheet resistance of the heating material has a large adjustable range. The planar heating material is scribed into strip-shaped heating elements by laser scribing. The heating resistance value of the heating element can be adjusted by changing the width and length of the heating element. The heating power of the electric heater can be adjusted very conveniently. It can also prepare electric heaters with high and low voltage and low current, which can meet the needs of spacecraft for high voltage flexible electric heaters.

[0029] 6) The irregular flexible electric heater prepared by the method of the present invention has very fine laser-etched lines. During the heating process, the heating element is heated in a planar manner, so its heating uniformity and heating efficiency are much greater than those of electric heaters in the aerospace field that use constantan alloy wire or constantan alloy foil as heating elements.

[0030] 7) The irregularly shaped flexible electric heater prepared by the method of the present invention has a total thickness of 20-500 μm. It is not only lightweight but also has low stiffness, making it convenient to use and install. The use of oxide semiconductor material as the heating element results in low material density and light weight, which is beneficial for weight reduction in spacecraft.

[0031] 8) The irregular flexible electric heater prepared by the method of the present invention uses oxide semiconductor thin film materials such as ITO, MZO, AZO, and TO as heating materials, and its transmittance is greater than 90%, which can be applied to heating special parts of the viewing window.

[0032] 9) The irregular flexible electric heater prepared by the method of the present invention adopts a layered structure. In addition to ensuring that the electric heater has good electrical performance, the layered structure can also adjust the specifications and dimensions of the electric heater, as well as the thickness and material of each layer, according to the usage requirements, so as to meet the special requirements of the flexible electric heater for special parts of the spacecraft. Attached Figure Description

[0033] Figure 1 This is a schematic flowchart of the method for preparing the irregularly shaped flexible electric heater of the present invention;

[0034] Figure 2 This is a schematic diagram of the electric heater structure obtained by the irregular flexible electric heater preparation method of the present invention;

[0035] Figure 3 This is a schematic diagram of the triangular irregularly shaped flexible electric heater obtained by the irregularly shaped flexible electric heater preparation method of the present invention.

[0036] Figure 4This is a schematic diagram of the structure of the irregularly shaped flexible electric heater combining circular and rectangular shapes obtained by the irregularly shaped flexible electric heater preparation method of the present invention.

[0037] Figure 5 This is a schematic diagram of the structure of the irregularly shaped flexible electric heater combining rectangular and trapezoidal shapes obtained by the irregularly shaped flexible electric heater preparation method of the present invention.

[0038] Figure 6 This is a schematic diagram of the structure of a circular irregularly shaped flexible electric heater obtained by the irregularly shaped flexible electric heater preparation method of the present invention.

[0039] Figure 7 This is a schematic diagram of the structure of the pentagonal irregular flexible electric heater obtained by the irregular flexible electric heater preparation method of the present invention.

[0040] Figure 8 This is a schematic diagram of the structure of the irregularly shaped flexible electric heater combining circular and rectangular shapes, obtained by the irregularly shaped flexible electric heater preparation method of the present invention.

[0041] In the picture:

[0042] 1-Upper insulating encapsulation layer; 2-Power line solder joint; 3-Heating element; 4-Lower insulating encapsulation layer;

[0043] 5-Power cord; 6-Edge insulation area Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0045] The present invention provides a method for preparing an irregularly shaped flexible electric heater, such as... Figure 1 As shown, this can be achieved through the following steps:

[0046] Step 1: Design the external dimensions and heating power of the electric heater according to actual usage requirements. For example, if the spacecraft needs to heat a triangular component and the heating temperature needs to be controlled between 30 and 50 degrees Celsius, the triangular electric heater can be designed with a triangular structure, the dimensions of which are consistent with the component to be heated, and the heating power and other performance indicators can be designed.

[0047] Step 2: Electrothermal conversion material is deposited on the lower insulating layer using a vacuum deposition method.

[0048] The heating material can be prepared on the upper surface of the lower insulating encapsulation layer using magnetron sputtering. When preparing the heating material, the vacuum degree should be no less than 5*10-3 Pa, the sputtering pressure should be 1.0*10-1~5*10-1 Pa, the sputtering power should be 1~15 kW, and the argon flow rate should be 50~300 sccm.

[0049] Step 3: Cut the lower insulating layer coated with electrothermal conversion material according to the design shape. The lower insulating layer coated with electrothermal conversion material can be cut manually, mechanically, or with laser. The shape and size after cutting should be the same as the part to be heated.

[0050] Step 4: Design the resistance value and distribution of the heating element of the electric heater.

[0051] First, design the heating element of the electric heater;

[0052] The heating element is designed as a strip with a width of not less than 5mm, and can be arranged in an S-shape or a spiral shape, or a combination of both; the heating power conforms to P=AU. 2 / (R □ ·S). Where, U is the operating voltage of the electric heater; R □ S is the sheet resistance of the heating material plated on the surface of the lower insulating encapsulation layer; S is the ratio of the length to the width of the strip-shaped heating element; A is the correction factor, the value of which varies between 0.7 and 1.3 depending on the heating material and the layout of the heating element, and the specific value is determined based on design experience.

[0053] After determining the aspect ratio S of the heating element, the width, length, and layout of the heating element are simulated using software according to the designed shape and size of the electric heater. While ensuring that the aspect ratio of the heating element remains unchanged, the changes in the width and length of the heating element are simulated to ensure that the heating element is evenly distributed within the heating area of ​​the electric heater (the outer ring covers the heating area of ​​the electric heater as much as possible, and the spacing between the strips of the inner bent parts is equal).

[0054] The order of steps 3 and 4 above can be interchanged.

[0055] Step 5: Based on the simulation results in Step 4, scribble the electrothermal conversion material on the surface of the cut lower insulating layer to form a heating element.

[0056] The electrothermal conversion material on the surface of the cut lower insulating layer is scribing using a laser scribing method. The specific method is as follows:

[0057] First, an insulating region is created around the edge of the lower insulating layer, scribing along the heating area of ​​the electric heater. This region forms the heating area inside the insulating area and the outer edge insulating region 6, preventing leakage at the edge after the electric heater is encapsulated. The electrothermal conversion material within this edge insulating region 6 can be removed or retained; if retained, it is essential to ensure that the electrothermal conversion material within the edge insulating region 6 is completely disconnected from the electrothermal conversion material within the internal heating area.

[0058] Subsequently, following the length, width, and layout of the heating element designed in step 4, the internal heating area is etched into strip-shaped heating elements with uniform length and width.

[0059] The aforementioned laser scribing method scribes a planar semiconductor thin-film heating material into strip-shaped heating elements, with laser scribing lines no wider than 150 μm. Because the laser scribing lines are extremely fine, the heating element is heated planarly during the electrical heating process, resulting in significantly higher heating uniformity and efficiency compared to electric heaters currently used in the aerospace field that employ constantan alloy wires or foils as heating elements. Furthermore, to prevent short circuits or leakage, all electrothermal conversion material at the scribed locations must be removed, exposing the upper surface of the lower insulating layer.

[0060] Step 6: Measure the insulation resistance between the heating element and the edge insulation area 6. If the insulation resistance is greater than 10kΩ, it means that the electrothermal conversion material in the edge insulation area 6 is completely disconnected from the electrothermal conversion material in the internal heating area, and the heating element is completed.

[0061] Step 7: Use a vacuum method to deposit a metal layer locally on the heating element as a power line solder joint.

[0062] A metal layer is deposited on the upper surface of the heating element's head and tail using vacuum evaporation to serve as the power line solder joints. Before preparing the power line solder joints, the heating element must be masked using a mask to prevent the evaporated metal material from depositing outside the solder joints. During the preparation of the power line solder joints, the vacuum level must be no less than 4 × 10⁻³ Pa, the operating current 1–6 A, and the power 4–10 kW. The power lines can be soldered onto the surface of the solder joints using manual soldering, ultrasonic soldering, or laser soldering.

[0063] The mask must be larger than the size of the electric heater to be fabricated, ensuring that the heating element, except for the mask's deposition windows, is fully concealed. The deposition windows are located at the beginning and end of the heating element, with a diameter of at least 5mm. Furthermore, the distance between adjacent windows at the beginning and end of the mask must be at least 5mm, meaning the closest distance between the two power line solder joints must be greater than 5mm to prevent short circuits. The masked lower insulating encapsulation layer is then placed in a vacuum evaporation machine, where a metal plating layer is deposited at the beginning and end of the heating element using vacuum evaporation deposition.

[0064] Step 8: Solder the power cord onto the surface of the power cord solder joint.

[0065] Step 9: Vacuum heat press encapsulation of the insulating layer to form a complete flexible electric heater.

[0066] The insulating encapsulation layer is encapsulated using a vacuum hot-pressing method. The vacuum degree of the vacuum hot-pressing encapsulation is not less than 5Pa, the hot-pressing temperature is 100-350℃, the heat preservation time is 10-90min, and hot-melt materials such as EVA, PVB, POE, epoxy resin, and polyimide are used as adhesives.

[0067] Based on the above method, an irregularly shaped flexible electric heater is obtained, such as... Figure 2 As shown, this is a three-layer structure with an shape consistent with the heating components required by the spacecraft, and a thickness controlled between 20 and 500 μm. It includes an upper insulating encapsulation layer 1, a lower insulating encapsulation layer 4, a heating element 3, a power line soldering point 2, and a power line 5. The upper and lower insulating encapsulation layers have the same shape and size and are symmetrically arranged. The materials of the upper insulating encapsulation layer 1 and the lower insulating encapsulation layer 4 are one of epoxy resin, silicone rubber, polyimide, and F46. Alternatively, several of these materials can be combined to form either the upper insulating encapsulation layer 1 or the lower insulating encapsulation layer 4.

[0068] Between the upper and lower insulating encapsulation layers is the heating element 3, which is a strip with a width of not less than 5 mm. After bending, it can be arranged in an S-shape or a spiral shape, or a combination of both. The outer contour of the heating element 3 covers the heating area of ​​the electric heater as much as possible, and the spacing between the strips at relatively opposite positions of the internal bent portions is equal. The outer contour of the heating element 3 and the circumferential direction of the lower insulating layer form an edge insulation region 6. The insulation resistance of the heating element is not less than 10 kΩ, and its thickness is 50 nm to 1000 nm. The heating material used in the heating element 3 is an oxide semiconductor material, including one of ITO, MZO, AZO, and TO. A composite of several of these materials can be used as the electrothermal conversion layer.

[0069] Power line soldering points 2 are designed at both ends of the upper surface of the heating element 3, located between the upper insulating encapsulation layer and the heating element 3; the material of the power line soldering points 2 is one or a mixture of copper, silver, aluminum, gold and tin, with a thickness of 50nm to 500nm; and the diameter of the power line soldering points 2 is not less than 5mm, and the closest distance between two power line soldering points 2 is greater than 5mm.

[0070] The power cord 5 is connected to the heating element 3 through the power cord soldering point 2, and is located between the upper insulating encapsulation layer 1 and the heating element 3.

[0071] Example 1

[0072] Based on actual usage requirements, the electric heater is designed as a triangle, with the external dimensions shown in Figure 3. According to the usage requirements of the electric heater, the working voltage of the electric heater is set to 220V and the heating power is 60W.

[0073] An AZO heating material was prepared on the surface of a 20 μm polyimide lower insulating encapsulation layer 4 using magnetron sputtering. The sputtering base vacuum was 5 × 10⁻³ Pa, and an argon-oxygen mixture with an argon-oxygen ratio of 200:1 was used as the sputtering gas. The sputtering pressure was 3 × 10⁻¹ Pa, and the sputtering power was 7 kW. The sheet resistance of the prepared AZO film was 50 Ω / □.

[0074] According to the shape and size of the designed electric heater, the lower insulating encapsulation layer 4, which has been plated with AZO, is manually cut.

[0075] Using the formula P = AU 2 / (R □ • S) The heating element 3 of the electric heater is designed. The value of A is taken as 1, and the aspect ratio S of the strip heating element 3 of the electric heater is determined to be approximately 16. Then, SolidWorks software is used to simulate the design according to the design dimensions of the electric heater. While keeping the aspect ratio of the heating element 3 unchanged, the width and length of the heating element 3 are adjusted so that the heating element 3 can be evenly distributed in the heating area of ​​the electric heater. For the heating element 3 of this embodiment, the first part of the strip heating element 3 is located at the apex of the triangle, and then it is arranged in an S-shape. The strips at the top and bottom of the S-shaped heating element 3 are parallel to the base of the triangle, and the tail of the strip heating element 3 is located at one of the base corners of the triangle.

[0076] Subsequently, laser scribing was used to first scribe the heating material into an edge insulation region 6 and an internal heating region. Then, according to the length, width, and layout of the simulated heating element 3, the internal heating region was scribed into a heating element 3 of corresponding length and width. Finally, a multimeter was used to measure the insulation resistance between the heating element 3 and the edge insulation region 6 after laser scribing. If the resistance was greater than 10kΩ, the heating element 3 was considered to be successfully fabricated.

[0077] The scribed heating element 3 is masked using a photomask, with 10mm diameter coating windows pre-drilled at the head and tail of the heating element 3. The masked lower insulating encapsulation layer 4 is then placed in a vacuum evaporation machine. Copper plating is performed on the head and tail of the heating element 3 using vacuum evaporation to deposit copper plating layers as power line solder points 2. The copper plating layer thickness is 200nm. During evaporation, the base vacuum level is not less than 3*10-3Pa, the operating current is 2A, and the power is 5KW.

[0078] The power cord 5 is soldered to the power cord soldering point 2 using manual soldering.

[0079] First, a layer of hot-melt polyimide is laid on the surface of the heating element 3 as an adhesive, and then a 20μm polyimide layer is laid as the upper insulating encapsulation layer 1. Then, it is placed in a vacuum laminator and kept at a vacuum degree of not less than 5Pa and a hot pressing temperature of 300℃ for 50 minutes to complete the preparation of the electric heater.

[0080] Example 2

[0081] Based on actual usage requirements, the electric heater is designed with an upper circular part and a lower rectangular part, and its external dimensions are shown in Figure 4. According to the usage requirements of the electric heater, the working voltage of the electric heater is set to 110V and the heating power is 40W.

[0082] MZO heating material was prepared on the surface of a 25 μm polyester lower insulating encapsulation layer 4 using magnetron sputtering. The sputtering base vacuum was 3 × 10⁻³ Pa, and an argon-oxygen mixture with an argon-oxygen ratio of 200:1 was used as the sputtering gas. The sputtering pressure was 2.5 × 10⁻¹ Pa, and the sputtering power was 6 kW. The sheet resistance of the prepared MZO thin film was 50 Ω / □.

[0083] According to the shape and size of the designed electric heater, the lower insulating encapsulation layer 4, which has been plated with MZO, is manually cut.

[0084] Based on the usage requirements of the electric heater, the operating voltage is set to 110V and the heating power to 40W, using the formula P = AU. 2 / (R □ • S) The heating element 3 of the electric heater is designed. With an A value of 1.2, the aspect ratio S of the heating element 3 is determined to be approximately 7.3. SolidWorks software is then used to simulate the design according to the heater's dimensions. While maintaining the aspect ratio of the heating element 3, the width and length of the heating element 3 are adjusted to ensure its uniform distribution within the heater's heating area. For the heating element 3 in this embodiment, the strip-shaped heating element 3 begins above the circular portion and then forms an S-shape. The strips at the top and bottom of this S-shaped heating element 3 are parallel to the base of the rectangular portion's triangle, and the tail of the strip-shaped heating element 3 is located at the bottom of the rectangular portion. Laser scribing is then used to first etch the heating material into an edge insulation area 6 and an internal heating area. Then, according to the simulated design of the heating element 3's length, width, and layout, the internal heating area is etched into heating elements 3 of corresponding length and width. Finally, using a multimeter to measure the insulation resistance of the heating element 3 and the edge insulation area 6 after laser marking, if it is greater than 10kΩ, then the heating element 3 is successfully manufactured.

[0085] The scribed heating element 3 is masked using a photomask, with circular coating windows of 10mm diameter pre-drilled at the head and tail of the heating element 3. The masked lower insulating encapsulation layer 4 is then placed in a vacuum evaporation machine, where aluminum plating is deposited at the head and tail of the heating element 3 using vacuum evaporation to serve as power line solder points 2. The aluminum plating thickness is 300nm. During evaporation, the base vacuum level is not less than 3*10-3Pa, the operating current is 2A, and the power is 5KW.

[0086] The power cord 5 is soldered to the power cord soldering point 2 using manual soldering.

[0087] First, a layer of EVA is laid on the surface of the heating element 3 as an adhesive, and then a 20μm layer of polyester is laid as the upper insulating encapsulation layer 1. Then, it is placed in a vacuum laminator and kept at a vacuum degree of not less than 5Pa and a hot pressing temperature of 120℃ for 20 minutes to complete the preparation of the electric heater.

[0088] Example 3

[0089] Based on actual usage requirements, the electric heater is designed with an upper rectangular part and a lower trapezoidal part, and its external dimensions are shown in Figure 5. According to the usage requirements of the electric heater, the working voltage of the electric heater is set to 60V and the heating power is 30W.

[0090] ITO heating material was prepared on the surface of a 25 μm polyimide lower insulating encapsulation layer 4 using magnetron sputtering. The sputtering base vacuum was 3 × 10⁻³ Pa, and an argon-oxygen mixture with an argon-oxygen ratio of 150:1 was used as the sputtering gas. The sputtering pressure was 3.5 × 10⁻¹ Pa, and the sputtering power was 10 kW. The sheet resistance of the prepared ITO film was 20 Ω / □.

[0091] According to the shape and size of the designed electric heater, the lower insulating encapsulation layer 4, which has been plated with ITO, is manually cut.

[0092] Based on the usage requirements of the electric heater, the operating voltage is set to 60V and the heating power to 30W, using the formula P = AU. 2 / (R □• S) The heating element 3 of the electric heater is designed. With an A value of 1, the aspect ratio S of the heating element 3 is determined to be 6. SolidWorks software is then used to simulate the design according to the heater's dimensions. While maintaining the aspect ratio of the heating element 3, the width and length of the heating element 3 are adjusted to ensure its uniform distribution within the heater's heating area. For the heating element 3 in this embodiment, the strip-shaped heating element 3 begins at the top of the rectangular portion and then forms an S-shape, with the strips at the top and bottom parallel to the bottom edge of the trapezoidal portion. The tail of the strip-shaped heating element 3 is located at the bottom of the trapezoidal portion. Laser scribing is then used to first scribe the heating material into an edge insulation area 6 and an internal heating area. Then, according to the simulated design of the heating element 3's length, width, and layout, the internal heating area is scribed into heating elements 3 of corresponding length and width. Finally, a multimeter is used to measure the insulation resistance of the heating element 3 and the edge insulation area 6 after laser scribing. If the resistance is greater than 10kΩ, the heating element 3 is considered complete.

[0093] The scribed heating element 3 is masked using a photomask, with circular coating windows of 5mm diameter pre-drilled at the head and tail of the heating element 3. The masked lower insulating encapsulation layer 4 is then placed in a vacuum evaporation machine. Aluminum plating is deposited at the head and tail of the heating element 3 using vacuum evaporation to serve as power line solder points 2. The aluminum plating thickness is 300nm. During evaporation, the base vacuum level is not less than 3*10-3Pa, the operating current is 2A, and the power is 5KW.

[0094] The power cord 5 is soldered to the power cord soldering point 2 using manual soldering.

[0095] A hot-melt polyimide adhesive is coated on the surface of the heating element 3, and then a 25μm layer of polyesteramide is laid as the upper insulating encapsulation layer 1. Then it is placed in a vacuum laminator and kept at a vacuum degree of not less than 5Pa and a hot pressing temperature of 300℃ for 40 minutes to complete the preparation of the electric heater.

[0096] Example 4

[0097] Based on actual usage requirements, the electric heater is designed to be circular, with the external dimensions shown in Figure 6. According to the usage requirements of the electric heater, the working voltage of the electric heater is set to 60V and the heating power is 40W.

[0098] ITO heating material was prepared on the surface of a 50 μm polyimide lower insulating encapsulation layer 4 using magnetron sputtering. The sputtering base vacuum was 3 × 10⁻³ Pa, and an argon-oxygen mixture with an argon-oxygen ratio of 150:1 was used as the sputtering gas. The sputtering pressure was 3.5 × 10⁻¹ Pa, and the sputtering power was 15 kW. The sheet resistance of the prepared ITO film was 5 Ω / □.

[0099] The electric heater's shape is designed according to usage requirements, such as... Figure 6 As shown, the lower insulating encapsulation layer 4, which has been plated with ITO, is then manually cut according to the shape and size of the designed electric heater.

[0100] Based on the usage requirements of the electric heater, the operating voltage is set to 60V and the heating power to 40W, using the formula P = AU. 2 / (R □ • S) The heating element 3 of the electric heater is designed. The value of A is 0.9, so the aspect ratio S of the heating element 3 is approximately 16. Then, SolidWorks software is used to simulate the design according to the design dimensions of the electric heater. While keeping the aspect ratio of the heating element 3 unchanged, the width and length of the heating element 3 are adjusted so that the heating element 3 can be evenly distributed in the heating area of ​​the electric heater. For the heating element 3 of this embodiment, the head and tail of the heating element 3 are located on both sides of the a end of a diameter A of the circle. The heating element 3 is arranged in a spiral shape. The method is as follows: starting from the head and tail, it moves in the opposite direction along the circumference of the circle to the b end of the diameter A, then bends and is arranged along the diameter A towards the center of the circle. Then it bends again and is arranged along the radius of the circle towards the a end of the diameter A. This bending is repeated until they intersect at the center of the circle. Then, laser scribing is used to first scribe the heating material into an edge insulation area 6 and an internal heating area. Next, according to the length, width, and layout of the simulated heating element 3, the internal heating area is scribed into a heating element 3 of corresponding length and width. Finally, a multimeter is used to measure the insulation resistance between the heating element 3 and the edge insulation area 6 after laser scribing. If the resistance is greater than 10kΩ, the heating element 3 is considered to be successfully fabricated.

[0101] The scribed heating element 3 is masked using a photomask, with 10mm diameter coating windows pre-drilled at the head and tail of the heating element 3. The masked lower insulating encapsulation layer 4 is then placed in a vacuum evaporation machine. Copper plating is performed on the head and tail of the heating element 3 using vacuum evaporation to deposit copper plating layers as power line solder points 2. The copper plating layer thickness is 200nm. During evaporation, the base vacuum level is not less than 3*10-3Pa, the operating current is 2A, and the power is 5KW.

[0102] The power cord 5 is soldered to the power cord soldering point 2 using manual soldering.

[0103] A hot-melt polyimide adhesive is coated on the surface of the heating element 3, and then a 50μm layer of polyimide is laid as the upper insulating encapsulation layer 1. Then it is placed in a vacuum laminator and kept at a vacuum degree of not less than 5Pa and a hot pressing temperature of 300℃ for 60 minutes to complete the preparation of the electric heater.

[0104] Example 5

[0105] Based on actual usage requirements, the electric heater is designed as a pentagon, with the external dimensions shown in Figure 7. According to the usage requirements of the electric heater, the working voltage of the electric heater is set to 36V and the heating power is 30W.

[0106] ITO heating material was prepared on the surface of a 6μm polyester lower insulating encapsulation layer 4 using magnetron sputtering. The sputtering base vacuum was 3 × 10⁻³ Pa, and an argon-oxygen mixture with an argon-oxygen ratio of 150:1 was used as the sputtering gas. The sputtering pressure was 3.5 × 10⁻¹ Pa, and the sputtering power was 15 kW. The sheet resistance of the prepared ITO film was 5 Ω / □.

[0107] According to the shape and size of the designed electric heater, the lower insulating encapsulation layer 4, which has already been plated with ITO, is manually cut as follows: Figure 7 The shape shown.

[0108] Based on the usage requirements of the electric heater, the operating voltage is set to 36V and the heating power to 30W. The formula P = AU² / (R) is used. □ • S) The heating element 3 of the electric heater is designed. With an A value of 1.1, the aspect ratio S of the heating element 3 is determined to be approximately 9.5. SolidWorks software is then used to simulate the design according to the heater's dimensions. While maintaining the aspect ratio of the heating element 3, the width and length of the heating element 3 are adjusted to ensure its uniform distribution within the heater's heating area. For the heating element 3 in this embodiment, the strip-shaped heating element 3 begins at one corner A of the pentagon, then arranges itself in an S-shape. The strips at the top and bottom of the S-shaped heating element 3 are parallel to the opposite sides of corner A, and the tail of the strip-shaped heating element 3 is located at one end of the opposite side of corner A. Laser scribing is then used to first etch the heating material into an edge insulation area 6 and an internal heating area. Then, according to the simulated design of the heating element 3's length, width, and layout, the internal heating area is etched into heating elements 3 of corresponding length and width. Finally, the insulation resistance of the heating element 3 and the edge insulation area 6 after laser marking is measured with a multimeter. If the insulation resistance is greater than 10kΩ, the heating element 3 is considered to be successfully manufactured.

[0109] The scribed heating element 3 is masked using a photomask, with circular coating windows of 10mm diameter pre-drilled at the head and tail of the heating element 3. The masked lower insulating encapsulation layer 4 is then placed in a vacuum evaporation machine. Copper plating is performed on the head and tail of the heating element 3 using vacuum evaporation to deposit copper plating layers as power line solder points 2. The copper plating layer thickness is 400nm. During evaporation, the base vacuum level is not less than 3*10-3Pa, the operating current is 2A, and the power is 5KW.

[0110] The power cord 5 is soldered to the power cord soldering point 2 using manual soldering.

[0111] A layer of EVA is laid on the surface of the heating element 3 as an adhesive, and then a 6μm layer of polyester is laid as the upper insulating encapsulation layer 1. Then it is placed in a vacuum laminator and kept at a vacuum degree of not less than 5Pa and a hot pressing temperature of 100℃ for 30 minutes to complete the preparation of the electric heater.

[0112] Example 6

[0113] Based on actual usage requirements, the electric heater is designed with a circular upper part and a trapezoidal lower part, as shown in Figure 8. According to the usage requirements of the electric heater, the working voltage of the electric heater is set to 220V and the heating power is 60W.

[0114] ITO heating material was prepared on the surface of a 50 μm polyimide lower insulating encapsulation layer 4 using magnetron sputtering. The sputtering base vacuum was 3 × 10⁻³ Pa, and an argon-oxygen mixture with an argon-oxygen ratio of 150:1 was used as the sputtering gas. The sputtering pressure was 3.5 × 10⁻¹ Pa, and the sputtering power was 15 kW. The sheet resistance of the prepared ITO film was 5 Ω / □.

[0115] The electric heater's shape is designed according to usage requirements, such as... Figure 8 As shown, the lower insulating encapsulation layer 4, which has been plated with ITO, is then manually cut according to the shape and size of the designed electric heater.

[0116] Based on the usage requirements of the electric heater, the operating voltage is set to 220V and the heating power to 60W, using the formula P = AU. 2 / (R □• S) The heating element 3 of the electric heater is designed. The value of A is 0.9, so the aspect ratio S of the heating element 3 is approximately 145. Then, SolidWorks software is used to simulate the design according to the design dimensions of the electric heater. While keeping the aspect ratio of the heating element 3 unchanged, the width and length of the heating element 3 are adjusted so that the heating element 3 can be evenly distributed in the heating area of ​​the electric heater. For the heating element 3 of this embodiment, the head and tail of the heating element 3 are respectively located on both sides of the end of the extension line of the circular diameter A in the rectangular part. The layout of the heating element 3 adopts a combination of S-shaped and spiral shape. The method is as follows: starting from the head and tail, it is arranged in an S-shape on both sides of the trapezoid, reaching both sides of the other end of the extension line; then it reaches the interior of the circular part along the diameter A, located on both sides of the a end of the diameter A, and finally arranged in the spiral shape in the circular part as described in the above embodiment 4. Then, laser marking is used to first mark the heating material into an edge insulation area 6 and an internal heating area. Next, according to the simulated design of the heating element 3's length, width, and layout, the internal heating area is marked into a heating element 3 of corresponding length and width. Finally, a multimeter is used to measure the insulation resistance between the laser-marked heating element 3 and the edge insulation area 6. If the resistance is greater than 10kΩ, the heating element 3 is considered to be successfully fabricated.

[0117] The scribed heating element 3 is masked using a photomask, with circular coating windows of 10mm diameter pre-drilled at the head and tail of the heating element 3. The masked lower insulating encapsulation layer 4 is then placed in a vacuum evaporation machine. Copper plating is performed on the head and tail of the heating element 3 using vacuum evaporation to deposit copper plating layers as power line solder points 2. The copper plating layer thickness is 300nm. During evaporation, the base vacuum level is not less than 3*10-3Pa, the operating current is 2A, and the power is 5KW.

[0118] The power cord 5 is soldered to the power cord soldering point 2 using manual soldering.

[0119] A layer of hot-melt polyimide adhesive is coated on the surface of the heating element 3, and then a 50μm layer of polyimide is laid as the upper insulating encapsulation layer 1. Then it is placed in a vacuum laminator and kept at a vacuum degree of not less than 5Pa and a hot pressing temperature of 300℃ for 60 minutes to complete the preparation of the electric heater.

[0120] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a profiled electric heater, characterized by: The following steps are taken: Step 1: Design the size and power of the electric heater according to actual use requirements; Step 2: Use vacuum coating method to deposit the electric heat conversion material on the lower insulating layer; Step 3: Cut the lower insulating layer with the electric heat conversion material according to the designed shape, and the shape and size after cutting are the same as the component to be heated; Step 4: Design the resistance value and distribution of the electric heater heating element; First, design the electric heater heating element; The heating element is a strip with a width not less than 5mm, which can be in S shape or spiral shape, or a combination of both; the heating power conforms to P=AU 2 / (R □ ·S); wherein, U is the working voltage of the electric heater; R □ is the square resistance of the surface of the lower insulating packaging layer plated with the electric heating material; S is the ratio of the length and width of the strip-shaped electric heating element; and A is a correction coefficient. After determining the aspect ratio of the heating element, use software to simulate the width, length and layout of the heating element. While keeping the aspect ratio of the heating element unchanged, the width and length of the heating element are simulated to be changed, so that the heating element can be evenly distributed in the heating area of the electric heater; Step 5: According to the simulation results in step 4, the surface of the cut lower insulating layer is scored, Form the heating element; First, score along the heating area of the electric heater, and make an insulating area around the edge of the lower insulating layer; the inner part is the heating area, and the outer part is the edge insulating area; Then, according to the length, width and layout of the heating element designed in step 4, the inner heating area is scored into strip-shaped heating elements with corresponding length and width; The electric heat conversion material in the scored part is completely removed, and the width of the scored part is not greater than 150µm; Step 6: Measure the insulation resistance of the heating element and the edge insulating area. If the insulation resistance is greater than 10kΩ, it indicates that the electric heat conversion material in the edge insulating area is completely disconnected from the electric heat conversion material in the inner heating area, and the electric heating element is completed; Step 7: Deposit a metal layer on the top surface of the head and tail of the heating element as the power line welding point; Step 8: Weld the power line on the surface of the power line welding point; Step 9: Vacuum hot-press package the upper insulating layer to form a complete flexible electric heater; The final special-shaped electric heater includes an upper insulating packaging layer, a lower insulating packaging layer, a heating element, a power line welding point and a power line; the upper and lower insulating packaging layers have the same shape and size and are symmetrically arranged; the heating element between the upper and lower insulating layers is a strip with a width not less than 5mm, which can be distributed in an S shape or a spiral shape after bending, or a combination of both; the strip spacing of the relative positions of the bending parts is equal; and the outer contour of the heating element and the circumferential interval of the lower insulating layer serve as the edge insulating area; the insulation resistance between the heating element and the edge insulating area is not less than 10kΩ; The power line welding point is designed at the top surface of the heating element at the head and tail positions, located between the upper insulating layer and the heating element; and the distance between the power line welding points adjacent to the head and tail of the heating element is not less than 5mm; The power line is connected to the heating element through the power line welding point and is located between the upper insulating packaging layer and the heating element.

2. The method of claim 1, wherein the method further comprises: The heating material is prepared on the upper surface of the lower insulating packaging layer by using the magnetron sputtering method in the vacuum coating method; the vacuum degree is not less than 5*10-3Pa, the sputtering gas pressure is 1.0*10-1~5*10-1Pa, the sputtering power is 1~15kW, and the argon gas flow is 50~300sccm.

3. The method of claim 1, wherein the method further comprises: The surface of the lower insulating layer after cutting is scored by laser scoring. ​ 4. The method of claim 1, wherein the method further comprises: A metal layer is deposited on the top surface of the head and tail of the heating element as a power line welding point by vacuum evaporation. ​ 5. The method of claim 4, wherein the step of forming the heating element comprises the steps of: forming a first layer of the heating element on the substrate; and forming a second layer of the heating element on the first layer of the heating element. When the power line welding point is prepared, the vacuum degree is not less than 4*10-3 Pa, the working current is 1-6 A, and the power is 4-10 KW.

6. The method for preparing an irregularly shaped electric heater as described in claim 4, characterized in that: Before the power line welding point is prepared, the heating element is masked by a mask plate; the size of the mask plate is larger than that of the electric heater to be prepared, so that the heating element is fully covered by the mask plate except the plating window position of the mask plate; the plating window of the mask plate is arranged at the head and tail of the heating element, and the diameter of the plating window is not less than 5 mm, and the distance between the plating window of the head and the plating window of the tail is not less than 5 mm.

7. The method of claim 1, wherein the method further comprises: The vacuum degree of the vacuum hot-press packaging is not less than 5 Pa, the hot-press temperature is 100-350℃, the holding time is 10-90 min, and EVA, PVB, POE, epoxy resin, polyimide and other hot-melt materials are used as the adhesive. ​ 8. The method of claim 1, wherein: In the distribution mode of the heating element, the spiral distribution is as follows: The head and the tail of the heating element are respectively located at the a end of a circular diameter A on both sides; starting from the head and the tail, the b end of the diameter A is reached after being reversely arranged along the circumference, then being bent along the diameter A to the center of the circle, and then being bent again to reach the a end of the diameter A along the circular radius, and the above steps are repeated until the center of the circle is reached.

9. The method of claim 1, wherein: The materials of the upper and lower insulating packaging layers are one of epoxy resin, silicone rubber, polyimide and F46, or several of the above materials are combined as the upper or lower insulating packaging layer; the material of the heating element is one of oxide semiconductor materials including ITO, MZO, AZO and TO, or several of the above materials are combined as the electric heat conversion layer, and the thickness is 50-1000 nm; the material of the power line welding point is one or several of copper, silver, aluminum, gold and tin.

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