Temperature-controlled thick film resistor and process for producing the same

Abstract

The application discloses a kind of temperature control thick film resistance and its production process in the technical field of thick film resistance electric auxiliary heating, to solve the problem of existing thick film resistance product in use process inadaptation of heating power to use environment.It includes substrate, working resistance film layer and auxiliary heating resistance film layer are arranged on the substrate, a plurality of first adapter terminals are arranged on the substrate for connecting working resistance film layer, and a plurality of second adapter terminals are arranged for connecting auxiliary heating resistance film layer, positive electrode circuit and negative electrode circuit are further arranged on the substrate, a plurality of parallel branches are arranged between positive electrode circuit and negative electrode circuit, a resistor and a temperature control switch are arranged in series on each parallel branch;The application is used to automatically control different heating power in complex environment, so as to maintain the temperature stability of thick film resistance as much as possible in different environments, thereby reducing the influence of temperature on its own performance, protecting service life and use effect.

Description

Technical Field

[0001] This invention relates to a temperature-controlled thick-film resistor and its manufacturing process, belonging to the field of thick-film resistor electric auxiliary heating technology. Background Technology

[0002] Thick film resistors are resistive elements formed by screen printing conductive paste (such as ruthenium oxide) onto a ceramic substrate and then sintering it at high temperature. Due to their advantages such as high temperature resistance, high power density, low cost, and flexible design, they are widely used in automotive electronics, industrial heating, home appliance control and other fields.

[0003] In practical applications of thick-film resistors, temperature is a key factor affecting their operational stability. Traditionally, a single temperature control switch is used to activate the heating circuit when the temperature is too low. However, this method is not suitable for extreme temperature environments, where the rated heating power cannot meet the operating temperature requirements. Even with continuous heating and temperature control, the temperature may still drop too low. Therefore, there is an urgent need for a thick-film resistor that can adjust the heating power in real time according to temperature changes to meet the requirements for stable operation in various environments. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a temperature-controlled thick film resistor and its manufacturing process, which can automatically control different heating powers in complex environments, thereby maintaining the temperature stability of the thick film resistor as much as possible in different environments, thereby reducing the impact of temperature on its own performance, and ensuring service life and performance.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] On one hand, the present invention provides a temperature-controlled thick-film resistor, comprising a substrate, wherein a working resistance film layer and an auxiliary heating resistance film layer are provided on the substrate, and a plurality of first adapter terminals are provided on the substrate for connecting the working resistance film layer and a plurality of second adapter terminals are provided for connecting the auxiliary heating resistance film layer. The substrate also comprises a positive electrode circuit and a negative electrode circuit that are isolated from each other, and a plurality of parallel branches are provided between the positive electrode circuit and the negative electrode circuit. A resistor and a temperature control switch are connected in series on each of the parallel branches. The positive electrode circuit or the negative electrode circuit is electrically connected to the second adapter terminals through the auxiliary heating resistance film layer.

[0007] Specifically, the auxiliary thermal resistance film layer is disposed on both sides of the substrate, and the substrate is provided with grouting holes that penetrate the auxiliary thermal resistance film layers on both sides of the substrate. The auxiliary thermal resistance film layers on both sides are electrically connected through conductive material injected into the grouting holes.

[0008] Specifically, the temperature control switch includes a mounting block and a contact block. The mounting block is equipped with a contact piece for contacting the contact block. The contact piece is made of two plates with different coefficients of thermal expansion stacked together. The mounting block and the contact block are located on opposite back sides of the working resistance film layer on the substrate.

[0009] Specifically, a main control temperature switch is also provided on the substrate. The main control temperature switch and the working resistance film layer are connected in series. The main control temperature switch is located on the back side opposite to the working resistance film layer of the substrate.

[0010] Specifically, the substrate is also provided with an encapsulation mask, which has a number of adjustment holes, each of which is positioned corresponding to the position of a contact piece. A sliding groove is provided on the back of the encapsulation mask, and a sliding piece is slidably disposed in the sliding groove. One side of the sliding piece is provided with teeth. An adjustment gear is provided on the substrate and on one side of each sliding piece, which can mesh with the corresponding teeth. One side of each sliding piece is provided with a contact that can move within the adjustment hole, and the contact can abut against the surface of the corresponding contact piece.

[0011] Specifically, an insulating block for supporting the contact piece is provided between every two adjacent mounting blocks and contact blocks. The contact can press the contact piece against the insulating block. A scale groove is provided along the sliding direction of the slider, and a temperature trigger mark is marked on the scale groove.

[0012] On the other hand, the present invention provides a manufacturing process for a temperature-controlled thick-film resistor, the manufacturing process comprising the following steps:

[0013] Prepare a substrate and sequentially print a conductor, a resistive paste, and a protective layer paste on the front and back sides of the substrate. The printed conductor includes a first adapter terminal, a second adapter terminal, and several sets of adjacent solder terminals. After each printing step, the substrate surface is dried at low temperature.

[0014] The substrate is sintered, and a dense resistive film is formed on both sides of the substrate;

[0015] The unwanted areas of the resistive film are removed by laser and a working resistive film layer is formed on the surface of the substrate, and an auxiliary heating resistive film layer is formed on at least one side of the substrate away from the working resistive film layer.

[0016] Weld mounting blocks with contact pieces and contact blocks to each group of adjacent welding terminals, and ensure that the welding position allows the contact pieces to properly abut against the contact blocks;

[0017] The product is packaged after connecting the parallel branch containing multiple temperature control switches and the corresponding resistors.

[0018] Specifically, when printing the conductor, the positive circuit, negative circuit, and parallel branch are printed simultaneously. When printing the parallel branch, the position for the resistor is reserved. When printing the resistor paste, it is printed at the required position of the resistor and connected in series with the temperature control switch of the parallel branch. The actual resistance value of the resistor is generated by laser adjustment of the resistive film in that area.

[0019] Specifically, when printing the conductor, the positive circuit, negative circuit, and parallel branch are printed simultaneously. When printing the parallel branch, the position for the resistor is reserved, and the resistor is soldered and installed at the reserved position.

[0020] Specifically, the resistors welded and installed are sliding rheostats; the regulator of the sliding rheostat is also installed when the package is encapsulated using a shield.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0022] This invention prints parallel control branches on the back of a thick-film resistor and uses a temperature switch to control the connection state of different branches at different temperatures. This allows the operating voltage of the auxiliary heating resistor film to be adjusted according to temperature. In other words, under different temperature environments, the temperature-controlled thick-film resistor can adjust the heating power of the auxiliary heating circuit according to the ambient temperature or the actual operating temperature. This can prevent the thick-film resistor from falling into a low-temperature operating state due to insufficient heating power. This method can automatically adjust the heating capacity of the resistor without manual adjustment, so that the thick-film resistor itself can maintain a better operating temperature, thereby improving the operating stability of the resistor and extending its service life. Attached Figure Description

[0023] Figure 1 This is a front structural schematic diagram of the thick film resistor provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the back structure of the thick film resistor provided in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the back packaging structure of the thick film resistor provided in an embodiment of the present invention;

[0026] Figure 4 This is the present invention. Figure 3 An enlarged view of the structure at point A of the thick-film resistor provided in the embodiment;

[0027] Figure 5 This is a schematic diagram of the overall structure of the thick film resistor processing device provided in an embodiment of the present invention;

[0028] Figure 6 This is the present invention. Figure 5 Enlarged view of section B of the thick film resistor processing apparatus provided in the embodiment;

[0029] Figure 7 This is a side sectional view of the thick film resistor processing apparatus provided in an embodiment of the present invention;

[0030] Figure 8 This is the present invention. Figure 7 Enlarged view of the structure at point C of the thick film resistor processing apparatus provided in the embodiment;

[0031] Reference numerals: 1. Substrate; 2. Working resistance film layer; 3. First adapter terminal; 4. Auxiliary heating resistance film layer; 5. Positive circuit; 6. Negative circuit; 7. Resistor; 8. Temperature control switch; 801. Mounting block; 802. Contact block; 803. Contact piece; 9. Second adapter terminal; 10. Grouting hole; 11. Main control temperature switch; 12. Encapsulation cover; 13. Slide groove; 14. Slider; 15. Adjusting gear; 16. Contact; 17. Scale groove; 18. Conveyor line; 19. Linear movement module; 20. Mounting bracket; 21. Printed screen; 22. Grout tank; 23. Air drying assembly; 24. Scraper assembly; 25. Parallel branch; 26. Drive device. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1

[0035] This invention provides a temperature-controlled thick-film resistor for automatically controlling different heating powers in complex environments, thereby maintaining the temperature stability of the thick-film resistor as much as possible under different conditions, reducing the impact of temperature on its performance, and ensuring service life and performance. To realize the structural function of the thick-film resistor product, the product includes a substrate 1, which can be made of high-purity alumina ceramic. The substrate 1 has a working resistance film layer 2 and an auxiliary heating resistance film layer 4. The working resistance film layer 2 is a working circuit with a pre-configured rated resistance. The auxiliary heating resistance film layer 4 generates heat when energized. The auxiliary heating resistance film layer 4 can be composed solely of a resistance film, or in some other embodiments, it can serve as a connection structure for connecting other heating elements. To ensure that the working resistance film layer 2 and the auxiliary heating resistance film layer 4 can operate normally, the substrate 1 can have several first adapter terminals 3 for connecting the working resistance film layer 2 and several second adapter terminals 9 for connecting the auxiliary heating resistance film layer 4. (See reference...) Figure 1 and Figure 2 As shown, in order to enable the thick film resistor product to automatically adjust the heating power according to the ambient temperature, a positive circuit 5 and a negative circuit 6 that are separated from each other are also provided on the substrate 1. The position and shape can be referred to Figure 2As shown, several parallel branches 25 are connected between the positive circuit 5 and the negative circuit 6. The positive circuit 5 and the negative circuit 6 are connected through these parallel branches 25. In order to control the heating power, a resistor 7 and a temperature control switch 8 are connected in series on each parallel branch 25. The trigger temperature of the temperature control switch 8 of different parallel branches 25 can be different. At this time, the positive circuit 5 or the negative circuit 6 can be electrically connected to the second adapter terminal 9 through the auxiliary heating resistor film layer 4. In the above embodiments, the temperature control switch 8 of the parallel branch 25 can disconnect the connection of the corresponding parallel branch 25 by means of high temperature disconnection. Taking the circuit system with two parallel branches 25 as an example, if a 50-ohm resistor 7 is connected in series on each parallel branch 25, at high temperature, one parallel branch 25 is open and the other is closed, then the actual working resistance is 50 ohms. At low temperature, the temperature control switches 8 of both parallel branches 25 are closed. At this time, the actual power adjustment resistor value is 25 ohms. By amplifying the current of the heating circuit, a higher heat generation of the auxiliary heating resistor film layer 4 can be achieved, thereby realizing automatic adjustment of the heating power according to the ambient temperature to adapt to different working environments of the thick film resistor product and maintain the excellent temperature control performance of the product itself. This improves the stability of the resistance value of the thick film resistor, prevents resistance value fluctuation and reduces the material deformation of the resistor product itself, which is beneficial to extending the service life of the product.

[0036] In some other embodiments of the present invention, a temperature-controlled thick-film resistor is provided. Considering that some thick-film resistor products need to be stacked with ceramic substrates 1 during use, if the auxiliary heating resistor film layer 4 is only set on one side of the substrate 1, the thermal conductivity of the substrate 1 portion above the stacked portion is limited, which is not conducive to stable temperature rise. In some other single-substrate 1 packaging environments, the heat needs to pass through the ceramic substrate 1 to act on the working resistor film layer 2 by setting the heating circuit on the back. In order to adapt to the temperature control requirements of these different working environments, the auxiliary heating resistor film layer 4 can be configured to be distributed on both sides of the substrate 1, and a grouting hole 10 is provided on the substrate 1 to penetrate the auxiliary heating resistor film layer 4 on both sides of the substrate 1, thereby realizing the series connection of the auxiliary heating resistor film layer 4 on both sides. The auxiliary heating resistor film layer 4 on both sides is electrically connected through the conductive material injected in the grouting hole 10. In this method, by placing the auxiliary heating resistor film layer 4 on both sides of the substrate 1, heating can be directly applied to the working resistor film layer 2. Since the auxiliary heating resistor film layer 4 is closer to the working resistor film layer 2, the ambient temperature of the working space can be effectively increased. When there is a need to stack the substrates 1, the newly added stacked substrates 1 do not require an additional back-side heating circuit. In the above embodiment, the stacked substrates 1 can also be composed of portions having a single-sided back-side heating circuit, forming a composite heating layer to ensure that the heating power meets the usage requirements.

[0037] This invention provides a temperature-controlled thick-film resistor, specifically a temperature control switch 8 in form and operation. Specifically, the temperature control switch 8 includes a mounting block 801 and a contact block 802, as described in the following embodiment. Figure 2 As shown, a contact piece 803 is mounted on the mounting block 801 to contact the contact block 802. The mounting block 801 and the contact block 802 are made of conductive and thermally conductive metal to transfer the temperature of the working resistance film layer 2 to the contact piece 803, causing it to deform. The contact piece 803 can be configured to be made of two plates with different coefficients of thermal expansion. When the temperature changes, the two plates bend due to their different deformation capabilities, thereby controlling their connection with the contact block 802. As a preferred configuration, the mounting block 801 and the contact block 802 should be positioned on the opposite back side of the working resistance film layer 2 on the substrate 1, so that the temperature at the working resistance film layer 2 can be directly fed back to the mounting block 801 and the contact piece 803.

[0038] The present invention provides a temperature-controlled thick-film resistor. To prevent the thick-film resistor from consuming power and generating heat even when the temperature is too high, thus causing an abnormal temperature rise, a main control temperature switch 11 can be provided on the substrate 1. Figure 2 The connection shown depicts a main control temperature switch 11 and a working resistance film layer 2 connected in series. In this configuration, the main control temperature switch 11 can be positioned on the back side of the working resistance film layer 2 on the substrate 1 to detect the operating temperature and trigger automatic operation. This trigger should disconnect the auxiliary heating resistance film layer 4 when the temperature is too high, thus preventing continuous heating. Alternatively, a corresponding temperature sensor can be installed on the substrate 1 to monitor the product's operating temperature.

[0039] This invention provides a temperature-controlled thick-film resistor. Since temperature changes the deformation of the contact 803, specifically, the longer the contact 803, the greater the deformation on the side furthest from the mounting block 801. To quickly adjust the temperature for the trigger circuit to switch on and off according to operational requirements, a packaging mask 12 is provided on the substrate 1. The packaging mask 12 has several adjustment holes, each corresponding to the position of the contact 803. (Refer to...) Figure 3 as well as Figure 4As shown, a groove 13 is provided on the back of the encapsulation shield 12, and a slider 14 is slidably disposed in the groove 13. One side of the slider 14 is provided with teeth. An adjustment gear 15 is provided on the substrate 1 on one side of each slider 14, which can mesh with the corresponding toothed part. A contact 16 is provided on one side of each slider 14, which can move in the adjustment hole. The contact 16 is configured to abut against the surface of the corresponding contact 803. With this configuration, the effective deformation length of the contact 803 can be manually adjusted, thereby changing the deformation capability of the contact 803 at the same temperature. When triggering is required, it manifests as a difference in temperature during triggering. To stably control the deformation and position of the contact 803, an insulating block for supporting the contact 803 can be provided between every two adjacent mounting blocks 801 and contact blocks 802. The contact 16 can then press the contact 803 against the insulating block to adjust the deformation of the extended end of the contact 803. A scale groove 17 is provided along the sliding direction of the slider 14, and a temperature trigger indicator is marked on the scale groove 17. Using this temperature trigger indicator, the trigger temperature of the thick-film resistor product can be quickly and manually adjusted, which is beneficial for testing and application in different scenarios. In some other embodiments, a similar method can be used to adjust the resistance value of the resistor 7. For example, the resistor 7 can be a sliding rheostat, using sliding contact to change the resistance value of the resistor 7, thereby achieving switching on and off at corresponding temperatures while changing the power of the auxiliary heating resistor film layer 4. This allows for better adaptation to various application scenarios, ensuring that the actual heating power meets the requirements. Example 2

[0040] This invention provides a manufacturing process for a temperature-controlled thick-film resistor, used to produce the temperature-controlled thick-film resistor product of one embodiment, enabling the prepared product to automatically regulate its heating power, and the manufacturing process includes the following steps:

[0041] Prepare a substrate 1, which may have a built-in grouting hole 10 or the grouting hole 10 may be processed by a machine later. Conductors (such as silver paste), resistive paste and protective layer paste (such as glass glaze layer) are sequentially printed on the front and back sides of the substrate 1. The printed conductors include at least a first adapter terminal 3, a second adapter terminal 9 and several sets of adjacent solder terminals. After each printing step, the surface of the substrate 1 is dried at a low temperature. The low temperature drying temperature is controlled below 150°C to quickly remove organic solvents from the paste.

[0042] The substrate 1 is sintered at a temperature higher than 850°C, and a dense resistive film is formed on both sides of the substrate 1 through sintering.

[0043] The unwanted areas of the resistive film are removed by laser action (ablation, adjustment, etc.) and a working resistive film layer 2 is formed on the surface of the substrate 1. An auxiliary heating resistive film layer 4 is formed on at least one side of the substrate 1 away from the working resistive film layer 2. The working resistive film layer 2 and the auxiliary heating resistive film layer 4 are processed simultaneously by laser action. The auxiliary heating resistive circuit is processed by directly utilizing the properties of the resistive paste itself, eliminating the need for a separate auxiliary heating circuit. This effectively saves on installation and preparation costs and improves processing efficiency.

[0044] Mounting blocks 801 and contact blocks 802 with contact pieces 803 are welded to each group of adjacent welding terminals. During welding, it is necessary to ensure the position height and distance of mounting blocks 801 and contact blocks 802 so that the welding position can meet the requirement that contact pieces 803 can properly abut against contact blocks 802. The stability of the welding position can be determined by pre-configuring pits on the substrate 1. The welding action ensures normal heat conduction while ensuring electrical connection. To avoid unstable melting of welding materials due to excessively high working temperature, tin wire with 0.7% copper or zinc-aluminum alloy can be used as welding material.

[0045] After connecting the parallel branch 25 containing multiple temperature control switches 8 and the corresponding resistor 7, the product is packaged. The resistor 7 can be an assembled sliding rheostat or a rated resistor. When it is a sliding rheostat, the regulator of the sliding rheostat can be installed at the same time as the package shield 12 is used for packaging, so as to adjust the power change of the heating circuit according to the calculation.

[0046] This invention provides a manufacturing process for a temperature-controlled thick-film resistor. To simplify the production steps and improve production efficiency, when printing the conductive material, conductive materials (such as silver paste) can be used to simultaneously print the positive circuit 5, the negative circuit 6, and the parallel branch 25. When printing the parallel branch 25, it should be connected to the corresponding solder terminals. The printed conductive material can fully utilize its conductivity at a small diameter, without additional installation, and can effectively improve the utilization rate of the substrate 1 surface. When printing the parallel branch 25, a position for the resistor 7 is reserved. When printing the resistive paste, the resistor 7 is printed at the required position and connected in series with the temperature control switch 8 of the parallel branch 25. Thus, the resistor 7 can also be directly prepared from the printed resistive paste. This allows for the direct processing of multiple circuit components or connectors using laser, effectively improving processing efficiency and accuracy. The actual resistance value of the resistor 7 can also be directly generated by laser adjustment of the resistive film in this area. Example 3

[0047] This invention provides a processing apparatus for temperature-controlled thick-film resistors, used for processing the temperature-controlled thick-film resistors in Embodiment 1. This apparatus facilitates rapid printing of pastes on the front and back sides of substrate 1. The apparatus includes:

[0048] Conveyor lines 18 with two conveyor surfaces facing each other, such as Figure 5 As shown, the belts of the two opposing conveyor lines 18 form a clamping area in the middle for clamping the substrate 1. The conveyor line 18 is used to clamp the substrate 1 and transport it forward in a vertical state. As a preferred embodiment, a positioning port can be provided on the substrate 1, and corresponding protrusions can be provided on the belt of the conveyor line 18 to prevent the substrate 1 from swinging during the clamping process. The conveyor line 18 has the ability to continuously transport, which facilitates efficient processing. As an optional alternative, in order to pursue the fixed stability of the substrate 1, a moving module with a specific shape positioning can be used to move back and forth to achieve stable transport of the substrate 1.

[0049] Linear movement modules 19 are provided on both sides above the two conveyor lines 18. Each linear movement module 19 is equipped with a mounting frame 20. The two mounting frames 20 can move closer to or further away from the clamping area through the linear movement modules 19. At this time, a printing screen 21 is provided on each mounting frame 20 in a vertical direction, so the linear movement module 19 can quickly align the printing screen 21 with the surface of the substrate 1. At this time, a squeegee assembly 24 for scraping the paste across the printing screen 21 is also provided on the mounting frame 20. The squeegee assembly 24 is used to apply the paste to be printed onto the surface of the substrate 1 that is in contact with the substrate.

[0050] The above structure allows the printing stencils 21 on both sides to align, press, and print during the clamping process of the substrate 1. This allows printing on both the front and back sides of the substrate 1 to be completed simultaneously while it is upright. This eliminates the need for low-temperature drying after printing on one side, followed by printing on the back side and low-temperature drying. This effectively reduces production steps and improves processing efficiency, which is beneficial for the efficient and rapid preparation of the required products.

[0051] This invention provides a processing apparatus for a temperature-controlled thick-film resistor. For a vertically placed printing screen 21, since the paste cannot be distributed evenly across the surface of the mesh openings, it is necessary to consider how to better allow the paste to pass through the mesh and be printed onto the substrate 1. Here, the printing screen 21 is configured with a fan-shaped overall structure, and a paste tank 22 located below the printing screen 21 is provided on the mounting frame 20. A squeegee assembly 24 is then configured to scrape and spread the paste from the paste tank 22 onto the printing screen. The mesh position of 21, that is, when the squeegee is in motion, can extend into the paste tank 22 and drive the paste to move to the mesh position above the screen, thus making it possible to provide paste for vertical printing. At this time, a drive device 26 for driving the squeegee assembly 24 to rotate is also provided on the mounting frame 20. A servo motor can be used for precise control. When drying at low temperature, consider setting an air drying assembly 23 downstream of the conveyor line 18, using air blowing on the substrate 1 being clamped, so as to quickly evaporate the organic solvents on both sides of the substrate 1 after printing.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A temperature-controlled thick-film resistor, characterized in that, The system includes a substrate (1), on which a working resistance film layer (2) and an auxiliary thermal resistance film layer (4) are provided. The substrate (1) is provided with a plurality of first adapter terminals (3) for connecting the working resistance film layer (2) and a plurality of second adapter terminals (9) for connecting the auxiliary thermal resistance film layer (4). The substrate (1) is also provided with a positive electrode circuit (5) and a negative electrode circuit (6) that are separated from each other. A plurality of parallel branches (25) are connected between the positive electrode circuit (5) and the negative electrode circuit (6). A resistor (7) and a temperature control switch (8) are connected in series on each of the parallel branches (25). The positive electrode circuit (5) or the negative electrode circuit (6) is electrically connected to the second adapter terminals (9) through the auxiliary thermal resistance film layer (4).

2. The temperature-controlled thick-film resistor according to claim 1, characterized in that, The auxiliary thermal resistance film layer (4) is disposed on both sides of the substrate (1). The substrate (1) is provided with a grouting hole (10) that penetrates the auxiliary thermal resistance film layer (4) on both sides of the substrate (1). The auxiliary thermal resistance film layer (4) on both sides is electrically connected through the conductive material injected into the grouting hole (10).

3. A temperature-controlled thick-film resistor according to claim 2, characterized in that, The temperature control switch (8) includes a mounting block (801) and a contact block (802). A contact piece (803) is mounted on the mounting block (801) for contacting the contact block (802). The contact piece (803) is made of two plates with different coefficients of thermal expansion. The mounting block (801) and the contact block (802) are located on the opposite back side of the working resistance film layer (2) on the substrate (1).

4. A temperature-controlled thick-film resistor according to claim 3, characterized in that, A main control temperature switch (11) is also provided on the substrate (1). The main control temperature switch (11) and the working resistance film layer (2) are connected in series. The main control temperature switch (11) is located on the back side opposite to the working resistance film layer (2) of the substrate (1).

5. A temperature-controlled thick-film resistor according to claim 3, characterized in that, The substrate (1) is also provided with an encapsulation mask (12). The encapsulation mask (12) is provided with a number of adjustment holes, and the position of each adjustment hole corresponds to the position of the contact (803). A sliding groove (13) is provided on the back side of the encapsulation mask (12). A sliding piece (14) is slidably disposed in the sliding groove (13). A tooth is provided on one side of the sliding piece (14). An adjustment gear (15) that can mesh with the corresponding tooth is provided on one side of each sliding piece (14) on the substrate (1). A contact (16) that can move in the adjustment hole is provided on one side of each sliding piece (14). The contact (16) can abut against the surface of the corresponding contact (803).

6. A temperature-controlled thick-film resistor according to claim 5, characterized in that, An insulating block for supporting the contact piece (803) is provided between each two adjacent mounting blocks (801) and contact blocks (802). The contact (16) can abut the contact piece (803) against the insulating block. A scale groove (17) is provided along the sliding direction of the slider (14). The scale groove (17) is marked with a temperature trigger mark.

7. A manufacturing process for a temperature-controlled thick-film resistor, used to produce the temperature-controlled thick-film resistor according to any one of claims 1-6, characterized in that, The production process includes the following steps: Prepare a substrate (1) and print a conductor, a resistive paste and a protective layer paste on the front and back sides of the substrate (1) in sequence. The printed conductor includes a first adapter terminal (3), a second adapter terminal (9) and several sets of adjacent solder terminals. After each printing step, the surface of the substrate (1) is dried at low temperature. The substrate (1) is sintered and a dense resistive film is formed on both sides of the substrate (1); The unwanted areas of the resistive film are removed by laser and a working resistive film layer (2) is formed on the surface of the substrate (1), and an auxiliary heating resistive film layer (4) is formed on at least one side of the substrate (1) away from the working resistive film layer (2). On each group of adjacent welding terminals, a mounting block (801) with a contact piece (803) and a contact block (802) are welded respectively, and the welding position is such that the contact piece (803) can properly abut against the contact block (802). After connecting the parallel branch (25) containing multiple temperature control switches (8) and the corresponding resistor (7), the product is packaged.

8. The manufacturing process for a temperature-controlled thick-film resistor according to claim 7, characterized in that, When printing the conductor, the positive circuit (5), negative circuit (6) and parallel branch (25) are printed simultaneously. When printing the parallel branch (25), the position for setting the resistor (7) is left. When printing the resistor paste, the resistor (7) is printed at the required position and connected in series with the temperature control switch (8) of the parallel branch (25). The actual resistance value of the resistor (7) is generated by laser adjustment of the resistive film in this area.

9. The manufacturing process for a temperature-controlled thick-film resistor according to claim 7, characterized in that, When printing the conductor, the positive circuit (5), negative circuit (6) and parallel branch (25) are printed simultaneously. When printing the parallel branch (25), the position for setting the resistor (7) is reserved. The resistor (7) is soldered and installed at the reserved position of the resistor (7).

10. The manufacturing process for a temperature-controlled thick-film resistor according to claim 9, characterized in that, The resistor (7) installed by welding is a sliding rheostat; the regulator of the sliding rheostat is installed at the same time when it is packaged by the encapsulation shield (12).

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