Ceramic capacitor

Abstract

The utility model relates to the technical field of sensors, and provides a ceramic capacitor, which comprises a substrate, a first electrode is arranged on the substrate, the first electrode comprises a first circuit and a first lead connected with the first circuit, and the circle center of the first circuit deviates from the circle center of the substrate; the diaphragm is arranged on one side of the substrate, a second electrode is arranged on the side face, close to the first electrode, of the diaphragm, the second electrode comprises a second circuit and a second lead connected with the second circuit, and the circle center of the second circuit deviates from the circle center of the diaphragm; the sealing layer is arranged between the substrate and the diaphragm; according to the ceramic capacitor, the assembling difficulty is reduced, and the automatic production efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of sensors, in particular to a ceramic capacitor. Background Art

[0002] Currently, most ceramic capacitors have a non-porous structure. Assembling ceramic capacitors into sensors requires additional electrical channels to achieve the transmission of different signals. Ceramic capacitors in existing technologies also have some through-hole designs at the axial position. Due to the directional assembly restrictions, this design requires strict alignment with the center of the circle, which increases the difficulty of assembly and has problems such as low assembly efficiency. Utility Model Content

[0003] The purpose of the present utility model is to overcome the defects of the prior art and provide a ceramic capacitor to reduce the difficulty of assembling a pressure sensor and to adapt to the complex circuit of an integrated temperature and pressure sensor.

[0004] In order to achieve the above and other purposes, the present invention is implemented by including the following technical solutions: the ceramic capacitor includes:

[0005] A substrate, on which a first electrode is provided, the first electrode includes a first circuit and a first lead connected to the first circuit, and the center of the first circuit deviates from the center of the substrate; a diaphragm is provided on one side of the substrate, and the diaphragm is provided with a second electrode on a side surface close to the first electrode, the second electrode includes a second circuit and a second lead connected to the second circuit, and the center of the second circuit deviates from the center of the diaphragm; and a sealing layer is provided between the substrate and the diaphragm; wherein, the substrate, the diaphragm and the sealing layer are all provided with a first through hole, and a plurality of second through holes are provided on the substrate, the first through hole is located on one side of the axis of the substrate, and the second through hole is located on the other side of the axis of the substrate, the sealing layer has an opening between the first through hole and the second through hole, the sealing layer, the substrate and the diaphragm form a cavity at the opening, the first circuit and the second circuit are located in the cavity and are provided between the first through hole and the second through hole, and the first lead and the second lead extend to the second through hole.

[0006] In one embodiment, a first grounding electrode is provided on the substrate, and the first grounding electrode is located outside the first electrode. The first grounding electrode includes a first annular electrode and a first grounding lead connected to the first annular electrode. The first annular electrode is located in the cavity, and the first grounding lead passes through the second through hole.

[0007] In one embodiment, a second grounding electrode is provided on the diaphragm, and the second grounding electrode is located outside the second electrode. The second grounding electrode includes a second annular electrode and a second grounding lead connected to the second annular electrode. The second annular electrode is located in the cavity, and the second grounding lead passes through the second through hole.

[0008] In one embodiment, the first through hole is a waist-shaped hole or a round hole.

[0009] In one embodiment, there are three second through holes, the first lead extends to the second through hole on one side, the second lead extends to the second through hole on the other side, and the first ground lead and the second ground lead pass through the second through hole in the middle.

[0010] In one embodiment, the thickness of the substrate is 1-10 mm, the radius of the substrate is 9-13 mm, the thickness of the diaphragm is 0.1-1 mm, and the radius of the diaphragm is 9-13 mm.

[0011] In one embodiment, the sealing layer covers the entire end surface of one side of the substrate, and the sealing layer is symmetrically provided with a first annular hole and a second annular hole on both sides of the opening.

[0012] In one embodiment, the ceramic capacitor has a positioning flat on an outer edge.

[0013] In one embodiment, the thickness of the first electrode is less than 1 μm, the thickness of the second electrode is less than 1 μm, and the thickness of the sealing layer is 10-25 μm.

[0014] In one embodiment, the substrate, the diaphragm and the sealing layer are all provided with penetrating positioning holes.

[0015] The utility model provides a ceramic capacitor encapsulated by a ceramic substrate and a ceramic diaphragm. A cavity with a specific gap forms an eccentric circular ceramic capacitor. Compared with the existing technology, the utility model has the following beneficial effects: eccentric through holes are provided on both the ceramic substrate and the ceramic diaphragm, providing an assembly path for the circuit elements to be combined with the pressure sensor, making it easier to integrate the ceramic capacitor into the complex circuit of the temperature and pressure integrated sensor.

[0016] The eccentric layout makes the electrode deviate from the center of the substrate, which can achieve multi-directional angular positioning (such as 0°, 90°, 180° and other assembly postures), solving the directional assembly limitations of traditional symmetrical designs.

[0017] Combined with the eccentric through-hole, different features can be flexibly selected to achieve positioning according to the equipment in each process of the automated production line, allowing the sensor to be quickly pre-assembled in the flow tooling, jig and fixture with an angle deviation of at least ±15°, shortening the automated production cycle, improving assembly efficiency and reducing production and assembly costs.

[0018] The inclined guide design of the eccentric through-hole further reduces assembly resistance, minimizes mechanical damage, and improves production line yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a schematic diagram of the structure of the ceramic capacitor of the utility model;

[0020] Figure 2 Shown is an exploded view of the ceramic capacitor of the utility model;

[0021] Figure 3 Shown is a bottom view of the ceramic capacitor substrate of the present invention;

[0022] Figure 4 Shown is a top view of the diaphragm of the utility model;

[0023] Figure 5 Shown is a cross-sectional view of the opening of the sealing layer of the utility model;

[0024] Figure 6 Shown is a schematic diagram of the structure of a ceramic capacitor in which the first through hole is circular;

[0025] 1-substrate, 2-diaphragm, 3-sealing layer, 31-opening, 32-first annular hole, 33-second annular hole, 34-avoidance hole, 4-first electrode, 41-first circuit, 42-first lead, 5-second electrode, 51-second circuit, 52-second lead, 6-first grounding electrode, 61-first annular circuit, 62-first grounding lead, 7-second grounding electrode, 71-second annular circuit, 72-second grounding lead, 8-conductive paste, 100-first through hole, 200-second through hole, 300-terminal, 400-positioning plane, 500-cavity, 600-positioning hole. DETAILED DESCRIPTION

[0026] like Figure 1As shown, the utility model provides a ceramic capacitor, and the working principle of the ceramic capacitor can be cited as follows. The internal electrodes of the ceramic capacitor have no contact with the external environment, and the pressure acts directly on the outer surface of the diaphragm 2. The diaphragm 2 and the inner surface of the substrate 1 are sputtered or screen-printed with electrodes to form a capacitor structure. According to the principle of a parallel plate capacitor, the capacitance change value caused by the deformation of the capacitor cavity is proportional to the deformation of the diaphragm 2, that is, the diaphragm 2 is proportional to the applied pressure, thereby measuring the pressure of the corresponding medium. During operation, the diaphragm 2 and the substrate 1 are in a non-contact state, that is, when the diaphragm 2 is deformed by an external load, the spacing between the capacitor cavities decreases, and the upper electrode and the lower electrode gradually approach each other, but never contact each other. The ceramic capacitor can be assembled into the inner cavity of the pressure sensor to feedback the pressure of the medium to be measured.

[0027] In some embodiments, the pressure sensor may be an integrated sensor for temperature and pressure, or an integrated sensor for temperature, humidity and pressure.

[0028] like Figure 2 As shown, the ceramic capacitor includes a substrate 1, a diaphragm 2 and a sealing layer 3 in the middle. The substrate 1, the diaphragm 2 and the sealing layer 3 can all be circular. The ceramic capacitor has a first through hole 100 passing through the substrate 1, the diaphragm 2 and the sealing layer 3. A plurality of second through holes 200 are provided on the substrate 1. The first through hole 100 can be located on one side of the axis of the ceramic capacitor, and the second through holes 200 can be provided on the other side of the axis of the ceramic capacitor. The first through hole 100 can be a waist-shaped hole, and the center spacing of the waist-shaped hole is 2-7 mm, for example, 2.8 mm, and the radius of the waist-shaped hole is 0.5-2 mm, for example, 1 mm.

[0029] like Figure 6 The first through hole 100 may also be a circular hole, for example, two circular holes, so that two transmission lines of the temperature sensor can pass through. One side of the first through hole 100 may also have a positioning hole 600 passing through the substrate 1, the diaphragm 2 and the sealing layer 3. The positioning hole 600 can allow the positioning pin in the inner cavity of the pressure sensor to pass through to assist in positioning the ceramic capacitor.

[0030] The first through hole 100 can provide a path for components to be assembled in the pressure sensor. The second through hole 200 can include three through holes, and the second through holes 200 can be used as lead holes to transmit the internal electrical signal of the ceramic capacitor to the outside.

[0031] like Figure 1As shown, the pressure sensor includes a substrate 1, which can be made of aluminum oxide or zirconium oxide. The cross-sectional structure of the substrate 1 can be circular, the thickness of the substrate 1 can be 1-10 mm, and the radius of the substrate 1 can be 9-13 mm.

[0032] like Figure 3 As shown, the bottom surface of the substrate 1 may be provided with a first electrode 4, which may be a power supply electrode. The first electrode 4 includes a first circuit 41 and a first lead 42 connected together. The first circuit 41 may be a circular circuit. The first circuit 41 may be located between the first through-hole 100 and the second through-hole 200, and the first lead 42 may extend toward the second through-hole 200. The center of the first circuit 41 does not coincide with the center of the bottom end surface of the substrate 1.

[0033] like Figure 3 As shown, the bottom surface of the substrate 1 may also be provided with a first grounding electrode 6. The first grounding electrode 6 may be entirely located around the first electrode 4, i.e., surround the first electrode 4. The first grounding electrode 6 may be hollow and include a first annular circuit 61 located around the first circuit 41 and a first grounding lead 62 located around the first lead 42. The first annular circuit 61 may be located between the first through-hole 100 and the second through-hole 200, and the first grounding lead 62 may extend toward the second through-hole 200.

[0034] The material of the first electrode 4 can be a conductive paste, such as gold, silver, or palladium. The thickness of the first electrode 4 is less than 1 μm. The material of the first ground electrode 6 is a conductive paste, such as gold, silver, or palladium. The thickness is less than 1 μm.

[0035] like Figure 4 As shown, the ceramic capacitor includes a diaphragm 2, which can be an elastic ceramic diaphragm. The diaphragm 2 can be made of alumina or zirconia. The thickness of the diaphragm 2 can be 0.1-1 mm. The diaphragm 2 can be circular. A second electrode 5 is provided on the top surface of the diaphragm 2. The second electrode 5 includes a second circuit 51 and a second lead 52 connected thereto. The second circuit 51 is a circular circuit. The radius of the second circuit 51 is greater than the radius of the first circuit 41. The second lead 52 is provided toward the second through hole 200. The second electrode 5 can be a signal electrode.

[0036] The thickness of the second electrode 5 is less than 1 μm, and the center of the second circuit 51 does not coincide with the center of the top end surface of the diaphragm 2 .

[0037] Specifically, the first lead 42 extends to the rightmost second through hole 200 , and the second lead 52 extends to the leftmost second through hole 200 .

[0038] like Figure 4 As shown, the top surface of the diaphragm 2 is also provided with a second grounding electrode 7, which can be arranged on the periphery of the second electrode 5. The shape of the second grounding electrode 7 can be similar to that of the first grounding electrode 6. The second grounding electrode 7 includes a second ring circuit 71 and a second grounding lead 72 connected to the second ring circuit 71. One end of the first grounding lead 62 and the second grounding lead 72 passes through the second through hole 200 in the middle.

[0039] The ceramic capacitor includes a sealing layer 3, which can be arranged between the substrate 1 and the diaphragm 2. The sealing layer 3 may include glass paste and insulating beads. The thickness of the sealing layer 3 depends on the diameter of the insulating beads. The thickness of the sealing layer 3 may be 10-25 μm, or even more. The sealing layer 3 is also circular.

[0040] like Figure 2 As shown, the membrane 2 and the side of the substrate 1 on which the electrodes are printed are close to each other and overlapped. The sealing layer 3 includes an opening 31 .

[0041] like Figure 5 As shown, the sealing layer 3 , the substrate 1 and the diaphragm 2 form a cavity 500 at the opening 31 , which is a pressure-sensing area.

[0042] like Figure 3 As shown, the sealing layer 3 has a first annular hole 32 and a second annular hole 33 symmetrically arranged on either side of the opening 31. The sealing layer 3 has an escape hole 34 corresponding to the second through hole 200 on the side of the opening 31 away from the first through hole 100. The first annular hole 32 and the second annular hole 33 effectively ensure sealing and minimize stress concentration, thereby improving the fatigue resistance of the ceramic capacitor.

[0043] like Figure 1 As shown, in some embodiments, a positioning plane 400 is formed by partially cutting an edge of one side of the ceramic capacitor, and the width of the positioning plane 400 is at least 2 mm.

[0044] The parallel plate capacitor formed by the first electrode 4 and the second electrode 5 serves as the main output signal of pressure. The parallel plate capacitor formed by the first grounding electrode 6 and the second grounding electrode 7 is grounded to shield parasitic capacitance and ensure the accuracy of the capacitance signal.

[0045] In one embodiment, the radius of the second circuit 51 is greater than the radius of the first circuit 41 , and the projections of the centers of the two circles may coincide with each other.

[0046] The preparation process of the present invention can be exemplified as follows:

[0047] The substrate 1 and the diaphragm 2 can be formed by casting or dry pressing and then sintering. Based on the substrate 1 and the diaphragm 2, the electrodes are brushed thereon by vacuum sputtering or screen printing. After sintering, the glass paste is brushed on the substrate 1, and the glass paste is sintered and solidified again to form a sealing layer 3. The substrate 1 and the diaphragm 2 are then combined together, the first electrode 4 is aligned with the second electrode 5, and then sintered at high temperature again to make the two tightly bonded together. A certain pressure needs to be maintained during the sintering process to avoid separation of the two ceramic sheets. By doping some high-temperature resistant insulating beads of fixed diameter into the glass paste, it can be ensured that the glass remains in a solid state when the paste melts, so as to ensure that the metal electrode planes do not contact each other and can maintain a basically fixed distance. This also ensures the consistency of the sensitive unit.

[0048] After the substrate 1 and the diaphragm 2 are assembled, a semi-solid conductive paste 8 can be injected into the second through hole 200 of the substrate 1, and then the terminal 300 is inserted. After curing, a ceramic capacitor that can lead out a capacitance signal can be obtained.

[0049] Therefore, the present invention effectively overcomes the shortcomings of the prior art and possesses high industrial value. The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by persons skilled in the art without departing from the spirit and technical principles disclosed in the present invention are intended to be covered by the claims of the present invention.

Claims

1. A ceramic capacitor, characterized in that: The ceramic capacitor includes: a substrate, wherein a first electrode is provided on the substrate, the first electrode includes a first circuit and a first lead connected to the first circuit, and the center of the first circuit deviates from the center of the substrate; a diaphragm disposed on one side of the substrate, wherein the diaphragm is provided with a second electrode on a side surface close to the first electrode, the second electrode including a second circuit and a second lead connected to the second circuit, and the center of the second circuit is offset from the center of the diaphragm; and a sealing layer disposed between the substrate and the diaphragm; In which, the substrate, the diaphragm and the sealing layer are all provided with a first through hole penetrating therethrough, and the substrate is provided with a plurality of second through holes, the first through hole is located on one side of the axis of the substrate, and the second through hole is located on the other side of the axis of the substrate, the sealing layer has an opening between the first through hole and the second through hole, the sealing layer and the substrate and the diaphragm form a cavity at the opening, the first circuit and the second circuit are located in the cavity and are arranged between the first through hole and the second through hole, and the first lead and the second lead extend to the second through hole.

2. The ceramic capacitor according to claim 1, wherein: A first grounding electrode is provided on the substrate, and the first grounding electrode is located outside the first electrode. The first grounding electrode includes a first annular electrode and a first grounding lead connected to the first annular electrode. The first annular electrode is located in the cavity, and the first grounding lead passes through the second through hole.

3. The ceramic capacitor according to claim 1, wherein: A second grounding electrode is provided on the diaphragm, and the second grounding electrode is located outside the second electrode. The second grounding electrode includes a second annular electrode and a second grounding lead connected to the second annular electrode. The second annular electrode is located in the cavity, and the second grounding lead passes through the second through hole.

4. The ceramic capacitor according to claim 1, wherein: The first through hole is a waist-shaped hole or a round hole.

5. The ceramic capacitor according to claim 2, wherein: There are three second through holes, the first lead extends to the second through hole on one side, the second lead extends to the second through hole on the other side, and the first ground lead and the second ground lead pass through the middle second through hole.

6. The ceramic capacitor according to claim 1, wherein: The thickness of the substrate is 1-10 mm, the radius of the substrate is 9-13 mm, the thickness of the diaphragm is 0.1-1 mm, and the radius of the diaphragm is 9-13 mm.

7. The ceramic capacitor according to claim 1, wherein: The sealing layer is fully covered on one end surface of the substrate, and the sealing layer is symmetrically provided with a first annular hole and a second annular hole on both sides of the opening.

8. The ceramic capacitor according to claim 1, wherein: The ceramic capacitor has a positioning flat on an outer edge.

9. The ceramic capacitor according to claim 1, wherein: The thickness of the first electrode is less than 1 μm, the thickness of the second electrode is less than 1 μm, and the thickness of the sealing layer is 10-25 μm.

10. The ceramic capacitor according to claim 1, wherein: The substrate, the diaphragm and the sealing layer are all provided with penetrating positioning holes.

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