A design method for alloy resistor structure

Abstract

The present invention discloses a design method of an alloy resistor structure, wherein the electrode region and the resistor region of the alloy resistor have a bending portion between them; the electrode region includes electrode metal, the resistor region includes resistor alloy, and there is a weld between the electrode metal and the resistor alloy; the design method includes the following steps: reducing or avoiding the proportion of electrode metal in the resistor region, increasing the proportion of alloy in the bending portion, and reducing the TCR value of the alloy resistor; and making the distance between the center of the resistor alloy and the electrode metal small. The design method of the alloy resistor of the present invention moves the weld outward to the bending portion, reduces or removes the proportion of copper in the resistor region, and can effectively reduce the TCR value of the alloy resistor.

Description

[0001] This application is a divisional application of the invention patent application with the application date of January 12, 2024, application number 2024100457720, and invention name "Foamed silicone breast prosthesis and preparation method thereof". Technical Field

[0002] The invention belongs to the technical field of alloy resistors, and in particular relates to a design method for a high-power, low-temperature drift, ultra-low resistance (0.3-4 mΩ) alloy resistor structure. Background Art

[0003] With the rapid development of social economy, electronic products or equipment have become an indispensable tool in people's daily work and life. People's demand for lightweight and precise electronic equipment is getting higher and higher, which leads to increasingly stringent requirements on the packaging of electronic components and the stability of characteristics at different temperatures.

[0004] Precision alloy resistors are one of the most important means of detecting current in circuits. Their temperature drift directly affects the accuracy and precision of circuit testing, especially for ultra-low resistance products (0.3-4mΩ). Due to the problem of resistance ratio, low temperature drift is more difficult to achieve (≤70ppm / ℃).

[0005] At the same time, the miniaturization of resistor components leads to poor heat dissipation and low power (≤6W). To this end, some existing technologies increase the heat dissipation by increasing the length of the resistor area, while increasing the cross-sectional area (thickness) of the resistor area to increase the power. However, the existing solutions still cannot meet the requirements of high power and low temperature drift in ultra-low resistance products.

[0006] Therefore, there is an urgent need for a miniaturized, high-power, low-temperature drift ultra-low resistance alloy resistor and a corresponding design method. Summary of the invention

[0007] In view of this, in order to overcome the defects of the prior art, the purpose of the present invention is to provide a design method for an alloy resistor structure, by redesigning the structure of the alloy resistor, so that the alloy resistor can achieve the effect of high power and low temperature drift.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A design method for an alloy resistor structure, the alloy resistor comprising a resistor region, electrode regions located on both sides of the resistor region, and a bending portion located between the electrode region and the resistor region; the electrode region comprises an electrode metal, the resistor region comprises a resistor alloy, and a weld is provided between the electrode metal and the resistor alloy;

[0010] The design method comprises the following steps:

[0011] Shorten the length of the resistance area and increase the length of the electrode area, so that the length of the resistance area is greater than the length of a single electrode area and less than the total length of the electrode area;

[0012] The welding seam is arranged on the bending portion so that the electrode area is completely electrode metal and the resistance area is completely resistance alloy;

[0013] The shape of the bending portion is set so that the angle between the line between the midpoint of the resistance area and the midpoint of the end surface of the electrode area close to the bending portion and the horizontal plane is 11° to 12°, so that the heat dissipation path is shorter and the heat dissipation effect is better.

[0014] According to some preferred implementation aspects of the present invention, the length of a single electrode region accounts for 30-32%; the length of the resistor region accounts for 32-34%.

[0015] According to some preferred implementation aspects of the present invention, the bending portion includes a lower bending arc, an inclined portion and an upper bending arc in sequence, the lower bending arc is close to the electrode area, the upper bending arc is close to the resistance area, and the inclined portion is located between the lower bending arc and the upper bending arc. The center of the circle corresponding to the lower bending arc is located above it, and the center of the circle corresponding to the upper bending arc is located below it.

[0016] According to some preferred implementation aspects of the present invention, the angle between the inclined portion and the horizontal plane is 70-80°, preferably 75°.

[0017] According to some preferred implementation aspects of the present invention, the radian corresponding to the lower bending arc is π / 3≤radian<π / 2; the radian corresponding to the upper bending arc is π / 3≤radian<π / 2.

[0018] According to some preferred implementation aspects of the present invention, the top surface of the resistance region is higher than the top surface of the electrode region, and the bottom surface of the resistance region is lower than the top surface of the electrode region.

[0019] According to some preferred implementation aspects of the present invention, a vertical height between a bottom surface of the resistor region and a bottom surface of the electrode region is 0.4±0.05 mm.

[0020] According to some preferred implementation aspects of the present invention, the thickness of the resistor region is 0.2-1.4 mm; the thickness of the electrode region is 0.2-1.4 mm.

[0021] According to some preferred implementation aspects of the present invention, the resistance of the alloy resistor is 0.3-4 mΩ.

[0022] According to some preferred implementation aspects of the present invention, the temperature drift of the alloy resistor is ≤40ppm / °C.

[0023] According to some preferred implementation aspects of the present invention, the power of the alloy resistor is 7-9W.

[0024] The present invention also provides an alloy resistor designed according to the above-mentioned design method.

[0025] Due to the adoption of the above technical solution, compared with the prior art, the benefit of the present invention lies in that the design method of the alloy resistor of the present invention moves the weld to the bent portion, reduces or removes the proportion of copper in the resistor area, and can effectively reduce the TCR value of the alloy resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 is a schematic diagram of the cross-sectional structure of an alloy resistor in an embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of the cross-sectional structure of an alloy resistor welded to a pad on a PCB in an embodiment of the present invention;

[0029] In the attached figure, 1: resistance alloy; 2: welding seam; 3: electrode metal; 4: welding pad. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0031] In the prior art, the means to increase the power of the product are to increase the length of the resistance area, thereby increasing the heat dissipation area between the resistance area and the air, or to increase the cross-sectional area to increase the power of the product. In the design method of the present application and the corresponding alloy resistor, by changing the heat dissipation path and increasing the heat dissipation method, the conductive heat dissipation between metal and metal (resistance area and electrode area) is increased to achieve faster heat dissipation, thereby reducing the surface temperature of the product, and achieving higher product power. Specifically, in the present invention, by shortening the length of the resistance area and increasing the length of the electrode area, the heat generated in the resistance area can be conducted to the electrode faster, and the thermal conductivity of the electrode material is much greater than the thermal conductivity of the air, so that the alloy resistor dissipates heat faster and can load more power; at the same time, the weld is moved outward, the proportion of copper in the resistance area is reduced or removed, and a low TCR is achieved to achieve a low temperature drift of the product.

[0032] Example 1 Alloy resistance

[0033] like Figure 1-2 As shown, the alloy resistor in this embodiment includes a resistor region, electrode regions located on both sides of the resistor region, and a bent portion located between the electrode region and the resistor region; the top surface of the resistor region is higher than the top surface of the electrode region, and the bottom surface of the resistor region is lower than the top surface of the electrode region. The electrode region includes electrode metal, the resistor region includes resistor alloy, and there is a weld between the electrode metal and the resistor alloy.

[0034] In this embodiment, the alloy resistor moves the weld position outward and is set on the bending portion, so that the electrode area is completely electrode metal and the resistor area is completely resistor alloy, reducing or avoiding the proportion of electrode metal in the resistor area, which can effectively reduce the TCR value of the alloy resistor and achieve the effect of low temperature drift.

[0035] In this embodiment, the length of the resistance area is shortened and the length of the electrode area is increased, so that the length of the resistance area is greater than the length of a single electrode area, but less than the total length of the two electrode areas. The length of a single electrode area accounts for 30-32%; the length of the resistance area accounts for 32-34%.

[0036] The bending portion includes a lower bending arc, an inclined portion and an upper bending arc in sequence. The lower bending arc is close to the electrode region, the upper bending arc is close to the resistance region, and the inclined portion is located between the lower bending arc and the upper bending arc. The center of the circle corresponding to the lower bending arc is located above it, and the center of the circle corresponding to the upper bending arc is located below it. The angle between the inclined portion and the horizontal plane is 70-80°, preferably 75°. The radian corresponding to the lower bending arc is π / 3≤radian<π / 2; the radian corresponding to the upper bending arc is π / 3≤radian<π / 2, both of which are preferably 5π / 12. In this embodiment, the shape of the above-mentioned bending portion is set so that the angle θ between the line L between the midpoint of the resistance region and the midpoint of the end surface of the electrode region close to the bending portion and the horizontal plane is 11°~12°, such as Figure 1 As shown. The above structure shortens the length of the resistor area, increases the length of the electrode area, and designs the structure of the bending portion, changes the heat conduction path to achieve heat conduction between metals (between the resistor area and the electrode area), achieves faster heat dissipation, and quickly reduces the surface temperature of the product.

[0037] The vertical height between the bottom surface of the resistor region and the bottom surface of the electrode region in this embodiment is 0.4±0.05mm. The thickness of the resistor region is 0.2-1.4mm; the thickness of the electrode region is 0.2-1.4mm. The resistance of the obtained alloy resistor is 0.3-4mΩ, the temperature drift is ≤40ppm / ℃, and the power is 7-9W.

[0038] By modifying the proportion of the electrode area and the resistor area in the alloy resistor and the angle θ between the connecting line L and the horizontal plane, Examples 1-3 are formed, as shown in Table 1 for details.

[0039] Comparative Example 1-3 Alloy Resistors

[0040] The structure of the alloy resistor in the comparative example is basically the same as that in the above-mentioned embodiment, except that the proportion of the electrode area and the resistor area, the angle θ between the connecting line L and the horizontal plane, and whether the weld is located on the bending portion are modified in the comparative example to form comparative examples 1-3, see Table 1 for details.

[0041] Embodiment 4 Design method

[0042] This embodiment provides a design method of the alloy resistor structure in the above embodiment, comprising the following steps:

[0043] (1) The length of the resistance region is shortened and the length of the electrode region is increased, so that the length of the resistance region is greater than the length of a single electrode region but less than the total length of the two electrode regions.

[0044] The length of a single electrode area accounts for 30-32%; the length of the resistor area accounts for 32-34%.

[0045] The thickness of the resistor region is 0.2-1.4 mm, and the thickness of the electrode region is 0.2-1.4 mm. The top surface of the resistor region is higher than the top surface of the electrode region, and the bottom surface of the resistor region is lower than the top surface of the electrode region.

[0046] (2) The weld is set on the bent portion so that the electrode area is completely electrode metal and the resistor area is completely resistor alloy.

[0047] (3) The shape of the bent portion is set so that the angle between the midpoint of the resistor region and the midpoint of the end surface of the electrode region close to the bent portion and the horizontal plane is 11° to 12°.

[0048] The bending portion includes a lower bending arc, an inclined portion and an upper bending arc in sequence, the lower bending arc is close to the electrode area, the upper bending arc is close to the resistance area, and the inclined portion is located between the lower bending arc and the upper bending arc. The center of the circle corresponding to the lower bending arc is located above it, and the center of the circle corresponding to the upper bending arc is located below it. The angle between the inclined portion and the horizontal plane is 70 to 80°, preferably 75°. The radian corresponding to the lower bending arc is π / 3≤radian<π / 2; the radian corresponding to the upper bending arc is π / 3≤radian<π / 2, and both are preferably 5π / 12.

[0049] The alloy resistor designed by the above design method has a resistance of 0.3-4 mΩ, a temperature drift of ≤40 ppm / °C, and a power of 7-9 W.

[0050] For the convenience of description and understanding, the above steps are numbered and described separately, but this is not limiting. In actual situations, at least some of the above steps can be performed simultaneously or in no particular order.

[0051] Tests and Results

[0052] The alloy resistors obtained in the examples and comparative examples were tested for resistance, temperature drift and power. The test methods for resistance, temperature drift and power refer to the provisions of IEC60115-14.5, MIL-STD-202Method304 and MIL-R-26E respectively. The test results are shown in Table 1 below:

[0053] Table 1 Parameters and corresponding test results

[0054]

[0055] The above test structure shows that: 1. The position of the weld has a significant effect on TCR. Moving the weld to the bend increases the proportion of alloy at the bend, and the product TCR decreases; 2. The smaller the distance between the center of the resistance alloy and the electrode, the greater the heat resistance of the product, that is, the higher the power. Among them, the results of Example 1 and Comparative Example 1 show that the proportion of the resistance area is less than 32%, and the resistance value accuracy is poor; the results of Example 1 and Comparative Example 2 show that the smaller the distance between the center of the resistance alloy and the electrode, the faster the product dissipates heat and the higher the power; the results of Example 3 and Comparative Example 3 show that the position of the weld has a significant effect on TCR, and the product TCR is significantly reduced at the bend of the weld.

[0056] The power of alloy resistor products is mainly determined by the surface temperature of the products, and the surface temperature of the products is mainly related to the thermal conductivity of the products. The thermal conductivity of air (0.0244W / (m·K)) is much smaller than the thermal conductivity of copper (401W / (m·K)). In this application, the heat conduction path is changed to achieve heat conduction between metals, thereby achieving faster heat dissipation and quickly reducing the surface temperature of the product. The lower the surface temperature, the higher the power that can be applied. The heat generated in the resistor area must be able to be discharged as quickly as possible. The closer to the electrode, the faster the heat conduction speed. Under the premise of the same product width (the same heat transfer area S), this application shortens the length of the resistor area and increases the length of the electrode area to achieve the purpose of reducing the heat conduction distance, thereby ensuring that the power performance of the product is better than that of its peers. Under the same product size, it can reach 7 to 9W.

[0057] At the same time, the resistance temperature coefficient of the product is related to the alloy material (resistance alloy) and part of the copper material (electrode metal) in the middle of the product. The resistance temperature coefficient of copper cannot be changed. The parameters that can be changed are the length of the alloy and the resistance temperature coefficient of the alloy:

[0058] Product resistance temperature coefficient: TCR = R1*TCR1+R2*TCR2

[0059] Among them, R1 is the resistance value contributed by copper in the resistor, which depends on the proportion of copper in the bending part; TCR1 is the TCR of copper, which is 3800ppm / ℃; R2 is the resistance value contributed by alloy in the resistor, which is the main body of the resistor; TCR2 is the TCR of alloy, which is about 0~-60ppm / ℃;

[0060] From the above formula, it can be seen that the TCR of copper is much greater than the TCR of alloy, and the less the resistance contribution of copper is, the smaller the TCR of the product is. Therefore, this application moves the weld to the bend, so that the proportion of copper in the resistance is significantly reduced, thereby effectively reducing the resistance temperature coefficient of the product.

[0061] The alloy resistor in this application changes the traditional design concept, and realizes high power of the product by reducing the resistor length, increasing the electrode length, and changing the heat dissipation path; by moving the weld outward, reducing or removing the proportion of copper in the resistor area, low TCR is achieved to achieve low temperature drift of the product. Specifically, the alloy resistor of the present invention, on the one hand, moves the weld outward to the bending part, reduces or removes the proportion of copper in the resistor area, and can effectively reduce the TCR value of the alloy resistor; on the other hand, by shortening the length of the resistor area and increasing the length of the electrode area, the heat generated in the resistor area can be conducted to the electrode faster, and the thermal conductivity of the electrode material is much greater than the thermal conductivity of the air, so that the alloy resistor dissipates heat faster and can load more power.

[0062] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0063] The above embodiments prepared by the method of the present invention are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A design method for an alloy resistor structure, characterized in that: The alloy resistor has a bent portion between the electrode region and the resistor region; the electrode region includes electrode metal, the resistor region includes resistor alloy, and a weld is provided between the electrode metal and the resistor alloy; The design method comprises the following steps: Reduce or avoid the proportion of electrode metal in the resistor area, increase the proportion of alloy in the bending part, reduce the TCR value of the alloy resistor; and make the distance between the center of the resistor alloy and the electrode metal small; The method of minimizing the distance between the center of the resistance alloy and the electrode metal comprises the steps of: setting the shape of the bending portion so that the angle between the line between the midpoint of the resistance region and the midpoint of the end surface of the electrode region close to the bending portion and the horizontal plane is 11° to 12°; The reducing or avoiding the proportion of electrode metal in the resistance area and increasing the proportion of alloy in the bending part comprises the steps of: arranging the weld on the bending part so that the electrode area is completely electrode metal and the resistance area is completely resistance alloy; The bending portion includes a lower bending arc, an inclined portion and an upper bending arc in sequence, the lower bending arc is close to the electrode area, the upper bending arc is close to the resistance area, and the inclined portion is located between the lower bending arc and the upper bending arc; A vertical height between a bottom surface of the resistor region and a bottom surface of the electrode region is 0.4±0.05 mm.

2. The design method according to claim 1, characterized in that: The center of the circle corresponding to the lower bending arc is located above it, and the center of the circle corresponding to the upper bending arc is located below it.

3. The design method according to claim 1, characterized in that: The angle between the inclined portion and the horizontal plane is 70-80°.

4. The design method according to claim 1, characterized in that: The radian corresponding to the lower bending arc is π / 3 ≤ radian < π / 2; the radian corresponding to the upper bending arc is π / 3 ≤ radian < π / 2.

5. The design method according to claim 1, characterized in that: The top surface of the resistance region is higher than the top surface of the electrode region.

6. The design method according to any one of claims 1 to 5, characterized in that: The resistance of the alloy resistor is 0.3-4 mΩ; the temperature drift of the alloy resistor is ≤40 ppm / °C; and the power of the alloy resistor is 7-9 W.

7. The design method according to any one of claims 1 to 5, characterized in that: The resistance temperature coefficient of the alloy resistor is calculated by the following formula: TCR=R1*TCR1+R2*TCR2; Among them, R1 is the resistance value contributed by copper in the resistor; TCR1 is the TCR of copper; R2 is the resistance value contributed by alloy in the resistor; TCR2 is the TCR of alloy.

Images