Miniature full-bridge resistance strain gauge for pressure sensors

Abstract

The application discloses a micro full-bridge resistance strain gauge for a pressure sensor, comprising four measuring grids and four pads; the four measuring grids and the four pads are arranged on a circular base, the four measuring grids comprise two outer grids and two inner grids; the two outer grids are arranged close to the outer diameter of the base and are symmetrically arranged above and below a horizontal axis of the base; the two inner grids are arranged at the center of the base and are symmetrically arranged left and right along a vertical axis of the base, single grid strips in the outer grids and the inner grids are arranged in parallel along the vertical direction, and the width of the single grid strips in the outer grids and the inner grids is 10-12 um. The sensitive grid line gap problem is avoided, the line quality is improved, and the processing technology is simplified.

Description

Technical Field

[0001] This invention belongs to the field of micro strain gauges and relates to a micro full-bridge resistance strain gauge for pressure sensors. Background Technology

[0002] Foil strain gauges are widely used in the fabrication of various sensors and in stress and strain testing under various environments. With the expansion of sensor applications, many consumer electronics products require performance testing, such as withstand voltage testing. Due to the miniaturization of consumer resistor products, the internal space is limited, resulting in a smaller area available for mounting. Therefore, the diameter of the selected diaphragm strain gauge for pressure sensors must be less than Ф4mm. Simultaneously, to reduce power consumption, the resistance value of the selected strain gauge must be high (≥1000Ω). Based on existing strain gauge manufacturing technology, conventional diaphragm strain gauges for pressure sensors, within a Ф4mm dimension, incorporate radial grids (thicker at the outer end, thinner at the inner end) and circumferential grids (in the arc direction). When the strain gauge resistance value is >350Ω, the strain gauge lines are exceptionally thin (approximately 20μm). During the manufacturing process, due to the anisotropic etching of the metal foil pattern, numerous tiny gaps are easily created in the circumferential grid of the strain gauge after etching, and there are also tiny gaps on the radial grid. Especially at the inner end of the radial grid, the sensitive grid is very thin and has tiny gaps, which causes abnormal changes in the strain gauge resistance value. When large deformation occurs, the sensor output becomes unstable. Therefore, the manufacturing process of diaphragm strain gauges for micro-pressure sensors is very difficult to achieve. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a miniature full-bridge resistance strain gauge for pressure sensors, which avoids the problem of missing sensitive grid lines, improves line quality and simplifies the processing technology.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] A miniature full-bridge resistance strain gauge for pressure sensors includes four measuring grids and four pads;

[0006] Four measurement gates and four pads are all set on a circular base. The four measurement gates include two outer gates and two inner gates.

[0007] The two outer grids are located close to the outer diameter of the base and are arranged symmetrically with respect to the horizontal axis of the base. The two inner grids are located at the center of the base and are arranged symmetrically with respect to the vertical axis of the base. The individual grid bars in both the outer and inner grids are arranged parallel to each other in the vertical direction. The width of each individual grid bar in both the outer and inner grids is 10um-12um.

[0008] Preferably, the two outer grids are measurement grid A and measurement grid C, the two inner grids are measurement grid B and measurement grid D, and the four pads are the first pad, the second pad, the third pad, and the fourth pad.

[0009] Measurement gate A is connected to the first and fourth pads, measurement gate B is connected to the first and second pads, measurement gate C is connected to the second and third pads, and measurement gate D is connected to the third and fourth pads, forming a fully sealed full-bridge circuit; measurement gate A and measurement gate C are a bridge pair, measurement gate B and measurement gate D are a bridge pair, the first and third pads are the inputs, and the second and fourth pads are the outputs.

[0010] Preferably, the outer grid is arc-shaped, with the center of the circle being the same as the center of the base circle.

[0011] Preferably, the outer grid is positioned at a position of Ф2.4mm-Ф2.8mm on the base.

[0012] Preferably, the overall width of the outer grille is 1.25mm.

[0013] Preferably, the inner grid is rectangular in shape.

[0014] Preferably, the inner grid is located at a position 0.4 mm away from the center of the base.

[0015] Preferably, the overall width of the inner grid is 0.5mm, and the length of a single grid bar is 0.8mm.

[0016] Preferably, the gap between the two inner grilles is set to be 0.05mm.

[0017] Preferably, the total width of the two inner gates is less than the width of a single outer gate.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention discloses a miniature full-bridge resistance strain gauge for a micro-pressure sensor. It achieves a rational arrangement of four measuring grids and four pads within a micro-scale. The direction of each individual grid bar within both the outer and inner grids is vertical, consistent with the direction of the metal foil rolling, avoiding issues such as gaps in the sensitive grid lines, improving line quality, and simplifying the manufacturing process. The small width of each grid bar enables the fabrication of large resistance within a micro-scale, reducing product power consumption and improving the linearity and measurement accuracy of the micro-sensor. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an embodiment of the miniature full-bridge strain gauge of the present invention;

[0021] Figure 2 This is a schematic diagram of a specific embodiment of the miniature full-bridge strain gauge of the present invention.

[0022] Wherein: 1-Measurement gate A; 2-First pad; 3-Measurement gate B; 4-Second pad; 5-Measurement gate C; 6-Third pad; 7-Measurement gate D; 8-Fourth pad; 9-Substrate. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions shown in the attached diagram, while the terms “inside” and “outside” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] like Figure 1 As shown, this is a miniature full-bridge strain gauge with a diaphragm structure for pressure sensors according to the present invention. The positions of the four measuring grids and the connection method between the four measuring grids and the four pads are marked.

[0027] The present invention relates to a miniature full-bridge resistance strain gauge for pressure sensors, which is provided with four measuring grids and four pads to form a diaphragm structure full-bridge resistance strain gauge. The measuring grids and pads are arranged on a circular substrate 9, with the measuring grids near the outer diameter of the substrate 9 being the outer grids and the measuring grids located at the center of the circular substrate being the inner grids.

[0028] The present invention relates to a miniature full-bridge resistance strain gauge for pressure sensors, which consists of four measuring grids and four pads. There are two outer grids, measuring grid A1 and measuring grid C5; and two inner grids, measuring grid B3 and measuring grid D7. There are four pads, designated as first pad 6, second pad 7, third pad 8, and fourth pad 9, which are respectively connected to the four measuring grids.

[0029] The present invention relates to a miniature full-bridge resistance strain gauge for pressure sensors, which has two outer grids, namely measuring grid A1 and measuring grid C5, for measuring negative strain; the individual grid bars of the outer grid are arranged in parallel along the vertical direction, and the individual grid bars are set with equal length. The outer grid is arc-shaped as a whole, and the center of the arc is the same as the center of the base 9; the outer grid is set at a position of Ф2.8mm on the base 9, and the overall width of the outer grid is 1.25mm. The measuring grids A1 and C5 are arranged symmetrically with respect to the horizontal axis of the base 9.

[0030] The present invention relates to a miniature full-bridge resistance strain gauge for pressure sensors, which has two inner grids, namely measuring grid B3 and measuring grid D7, for measuring normal strain; the individual grid bars in the inner grid are arranged in parallel along the vertical direction, and the individual grid bars are set with equal length, and the inner grid as a whole is rectangular; the overall width of the inner grid is 0.5mm, and the length of each individual grid bar is 0.8mm; the inner grid is set at a position 0.4mm away from the center of the base 9, and measuring grid B3 and measuring grid D7 are arranged symmetrically about the vertical axis of the base 9.

[0031] The gap between the two inner grilles is set to 0.05mm, so the total width of the two inner grilles is 1.05mm.

[0032] The present invention relates to a miniature full-bridge resistance strain gauge for pressure sensors, wherein the total width of the two inner grids is smaller than the width of a single outer grid, ensuring that the sealing cover of the strain gauge can fully protect all four sensitive grids.

[0033] Both the outer and inner grids have a single grid bar width of 10um-12um, enabling the fabrication of large resistors in a tiny size, reducing product power consumption, and improving the linearity and measurement accuracy of the micro sensor.

[0034] The present invention relates to a miniature full-bridge resistance strain gauge for pressure sensors, which consists of two inner grids, two outer grids, and four pads forming a fully sealed full-bridge strain gauge. Each pad is connected to two different measuring grids. The two outer grids are arranged on one pair of bridges, and the two inner grids are arranged on another pair of bridges.

[0035] Measurement gate A1 is connected to the first, second, and fourth pads 8; measurement gate B3 is connected to the first, second, and second and fourth pads; measurement gate C5 is connected to the second, fourth, and third pads 6; and measurement gate D7 is connected to the third pad 6 and fourth pad 8, forming a fully sealed full-bridge circuit.

[0036] Measurement gates A1 and C5 form a bridge, and measurement gates B3 and D7 form a bridge. The first and second pads (6) and the third pad (6) are defined as inputs, and the second and fourth pads (8) are defined as outputs.

[0037] Figure 2 The illustrated embodiment is Figure 1This embodiment is a special case, suitable for detecting smaller measurement areas. The miniature full-bridge strain gauge with a diaphragm structure for a tiny pressure sensor in this invention is completely consistent with the embodiment. The positions of the four measuring grids are indicated, and the connection method between the four measuring grids and the four pads is also the same.

[0038] The outer grid for implementing the special case is set at a position of Ф2.4mm, and measuring grids A1 and C5 are arranged symmetrically with respect to the horizontal axis.

[0039] In summary, the miniature full-bridge strain gauge for a micro pressure sensor of the present invention is inventive and is not limited to the four-grid diaphragm structure of the embodiment, but can be extended to resistance strain gauges with more sensitive grids and more pads.

[0040] The present invention relates to a miniature full-bridge strain gauge for a micro pressure sensor. Based on existing strain gauge manufacturing technology, and combined with the new strain gauge graphic design method and manufacturing technology developed in this invention, it provides customers with a stable and easy-to-use miniature full-bridge strain gauge, improves the linearity and measurement accuracy of the micro pressure sensor, accelerates the application and market promotion of the product, and will create higher market value in the future.

[0041] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0042] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A miniature full-bridge resistance strain gauge for pressure sensors, characterized in that, Includes four measurement gates and four pads; Four measuring gates and four pads are all set on a circular base (9). The four measuring gates include two outer gates and two inner gates. Two outer grids are located close to the outer diameter of the base (9) and are arranged symmetrically with respect to the horizontal axis of the base (9); two inner grids are located at the center of the base (9) and are arranged symmetrically with respect to the vertical axis of the base (9). The single grid bars in the outer grid and the inner grid are arranged parallel to each other in the vertical direction. The width of the single grid bar in the outer grid and the inner grid is 10um-12um. The two outer grids are measurement grid A (1) and measurement grid C (5), the two inner grids are measurement grid B (3) and measurement grid D (7), and the four pads are the first pad (2), the second pad (4), the third pad (6), and the fourth pad (8). Measurement gate A (1) is connected to the first pad (2) and the fourth pad (8), measurement gate B (3) is connected to the first pad (2) and the second pad (4), measurement gate C (5) is connected to the second pad (4) and the third pad (6), and measurement gate D (7) is connected to the third pad (6) and the fourth pad (8), forming a fully sealed full-bridge circuit; measurement gate A (1) and measurement gate C (5) are a bridge, measurement gate B (3) and measurement gate D (7) are a bridge, the first pad (2) and the third pad (6) are the inputs, and the second pad (4) and the fourth pad (8) are the outputs; The outer grid is set at a position of Ф2.4mm-Ф2.8mm on the base (9).

2. The miniature full-bridge resistance strain gauge for pressure sensors according to claim 1, characterized in that, The outer grid is arc-shaped, and its center is the same as the center of the base (9).

3. The miniature full-bridge resistance strain gauge for pressure sensors according to claim 1, characterized in that, The overall width of the outer grille is 1.25mm.

4. The miniature full-bridge resistance strain gauge for pressure sensors according to claim 1, characterized in that, The inner grid is rectangular in shape.

5. The miniature full-bridge resistance strain gauge for pressure sensors according to claim 1, characterized in that, The inner grid is set at a position 0.4 mm away from the center of the base (9).

6. The miniature full-bridge resistance strain gauge for pressure sensors according to claim 1, characterized in that, The overall width of the inner grid is 0.5mm, and the length of a single grid bar is 0.8mm.

7. The miniature full-bridge resistance strain gauge for pressure sensors according to claim 1, characterized in that, The gap between the two inner grilles is set to 0.05mm.

8. The miniature full-bridge resistance strain gauge for pressure sensors according to claim 1, characterized in that, The total width of the two inner gates is less than the width of a single outer gate.

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