KR100962022B1 - Capacitive pressure sensor and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A capacitive pressure sensor and a manufacturing method thereof are provided to rapidly and simply perform a manufacturing process, and to simplify a work without a spot welding process. CONSTITUTION: A capacitive pressure sensor comprises a cover member(110), a body(100), and coupling members(120). A first electrode(150) is formed in the cover member. The body is installed in the bottom of the cover member. The coupling members are formed between the cover member and the body, and couples the cover member and the body. Mounting grooves(145a,145b,145c) are formed in the body part. Contact holes(210a,210b) are formed in the bottom of the mounting grooves.

Description

CAPACITIVE PRESSURE SENSOR AND MANUFACTURING METHOD THEREOF

The present invention relates to a capacitive pressure sensor and a method for manufacturing the same, and more particularly, to a capacitive pressure sensor and a method for manufacturing the conductive electrode is inserted and bonded separately.

In general, a capacitive pressure sensor is an energy conversion device that converts mechanical energy into electrical energy. Such capacitive pressure sensors are used in level transmitters that continuously measure water levels or flow in ballast tanks, water tanks and oil tanks for ships.

The structure of such a capacitive pressure sensor will be briefly described with reference to FIG. 1, the body portion 10 having the conductive electrodes 14a and 14b disposed on an upper surface thereof, and the conductive electrode 15 disposed on an upper side of the body portion disposed thereon. ) Is formed between the cover member 11 and the body portion 10 and the cover member 11, the bonding member 12 for bonding the body portion 10 and the cover member 11.

In constructing the pressure sensor as described above, conventionally, electrodes 14a and 14b provided on the upper side of the body part are formed by depositing a thin film of a conductive metal material, so that an electrode having high flatness can be obtained. In general, sputter deposition was used a lot.

In addition, connection terminals 20a, 20b, and 20c for connecting the electrodes 14a, 14b, and 15 to an external circuit unit (not shown) located outside are generally disposed in the contact holes 21a, 21b, and 21c of the body part. It was fixed a lot by spot welding.

However, as described above, the method of forming the thin films of the electrodes 14a, 14b, and 15 by the sputter deposition method is slow in forming the thin films, and it is difficult to form electrodes of the same quality when the pressure sensor is mass-produced.

In addition, since the electrodes 14a and 14b of the body portion 10 and the electrodes 15 of the cover member 11 must maintain a predetermined distance, the manufacturing cost is increased by increasing the height of the expensive bonding member 12. There was a rising issue.

Meanwhile, the method of fixing the connection terminals 20a, 20b, and 20c by spot welding requires expensive equipment for spot welding, and the welding work for each small connection terminal (lead wire) is precise. The task was complicated and difficult.

In addition, since the spot welded portions are not flat, the electrodes 14a and 14b deposited in contact with the weld portions of the connection terminals 20b and 20c, that is, the ends of the connection terminals 20b and 20c, are formed flat. There was also a difficult problem.

Accordingly, it is an object of the present invention to provide a capacitive pressure sensor and a method for manufacturing the same, which are simple and fast in manufacturing and easy to form electrodes of uniform quality.

The present invention for achieving the above object is a cover member formed with a first electrode,

A capacitive type provided at a lower side of the cover member and including a body portion provided with a second electrode facing the first electrode at a predetermined distance, and a bonding member for bonding both of the cover member and the body portion to each other; In the pressure sensor, a seating groove is formed in the body portion, the second electrode is inserted into the seating groove and fixed, and a contact hole is formed below the seating groove to be electrically connected to the second electrode. Provides capacitive pressure sensors with terminals.

In addition, in the present invention, the second electrode is fixed to the seating groove by a conductive electrode assembly inserted below. The connection terminal is configured to be electrically connected to the second electrode through the electrode assembly.

In addition, in the present invention, the second electrode is divided into inner and outer electrodes, and the seating grooves are formed to correspond to the inner and outer electrodes, respectively.

On the other hand, the method of manufacturing a body portion of the capacitive pressure sensor as described above, the method comprising the steps of preparing a seating groove into which the electrode is inserted and the body portion formed with a contact hole in the lower side of the seating groove; Sequentially inserting a conductive electrode assembly and an electrode into the seating groove; And installing a connection terminal in the contact hole to be electrically connected to the electrode after the electrode assembly and the electrode are inserted.

The present invention may further include fixing the electrode to the body part by heating the electrode assembly after the electrode assembly and the electrode are inserted.

In the present invention, in the step of installing the connection terminal, it is preferable to electrically connect the electrode and the connection terminal by heating the electrode assembly and the connection terminal at the same time.

In the installing of the connection terminal, the connection terminal may be formed by filling a conductive paste or a conductive metal powder in the contact hole, heating, and curing the conductive terminal.

In another aspect, the present invention provides a cover member having a first electrode, a body portion provided below the cover member and having a second electrode facing the first electrode at a predetermined interval, and the cover member and the body portion. In the manufacturing method of the capacitive pressure sensor comprising a bonding member for bonding both therebetween, the method comprising the steps of preparing a seating groove into which the second electrode is inserted and a body portion through which a contact hole penetrates below the seating groove; Sequentially inserting a conductive electrode assembly and the second electrode into the seating groove; Installing a connection terminal in the contact hole to be electrically connected to the second electrode after the second electrode is inserted into the seating groove; And bonding the cover member and the body part with the bonding member so that the second electrode faces the first electrode at a predetermined interval.

The present invention as described above, after the step of inserting the electrode assembly and the second electrode, is configured to further include the step of heating the electrode assembly to fix the second electrode to the body portion.

In addition, the step of installing the connection terminal, it is preferable to include the step of filling the conductive hole (paste) or conductive metal powder in the contact hole, and curing by heating.

The connecting terminal may include filling a conductive paste or a conductive metal powder in the contact hole, simultaneously heating the paste or the metal powder and the electrode assembly to connect the second electrode to the body portion. It is preferable to fix on and to cure the paste or metal powder.

In addition, the installing of the connection terminal may be configured such that the second electrode is simultaneously bonded to the connection terminal and the body part by heating the electrode assembly.

The present invention as described above has the following effects.

First, the present invention is a method of manufacturing the electrode separately and inserting it into the mounting groove, it is faster than the process of forming the electrode thin film by the sputter (sputter) deposition process can be very simple to proceed.

Second, since the electrode of the present invention is manufactured in a separate plate shape, it is possible to process the electrode into a more accurate plate shape than the sputter deposition process. Accordingly, the sensitivity of the capacitive pressure sensor can be increased to enable more accurate pressure measurement. In addition, since the electrode is manufactured by attaching separately, it is possible to produce a pressure sensor of uniform quality.

Third, the present invention has a structure in which the electrode is embedded in the seating groove formed in the interior of the main body, the height of the bonding member for maintaining a proper distance between the first electrode and the second electrode is lower than the conventional capacitive pressure sensor Can be. Therefore, the amount of expensive joining members can be reduced.

Fourth, the present invention can be installed by soldering or filling the paste, so that the spot welding process required in the conventional manufacturing process is unnecessary, does not require precise work, and can simplify the work. .

Fifth, since the above-mentioned sputter deposition process and spot welding process are removed, expensive equipment is not required, and the problem of quality imbalance caused by the processes can be solved.

1 is a cross-sectional view of a conventional capacitive pressure sensor
2 is a perspective view of a capacitive pressure sensor according to an embodiment of the present invention;
3 is a plan view of the body portion according to an embodiment of the present invention
4 is a cross-sectional view taken along the line AA of FIGS. 2 and 3;
5 is a sectional view taken along the line BB of FIGS. 2 and 3;
6 is an explanatory diagram illustrating a method of forming a second electrode according to an embodiment of the present invention.
7 to 10 are explanatory diagrams showing various methods of forming connection terminals according to an embodiment of the present invention.
11 is an explanatory view showing a method of joining a cover member to a main body according to an embodiment of the present invention;
12 is an operation explanatory diagram of a capacitive pressure sensor according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 2 is a perspective view of a pressure sensor according to the present invention. 3 is a plan view of a capacitive pressure sensor body part according to an exemplary embodiment of the present invention. 4 is a cross-sectional view taken along the line AA ′ of FIGS. 2 and 3, and FIG. 5 is a cross-sectional view taken along the line B-B ′ of FIGS. 2 and 3.

2 to 5, the capacitive pressure sensor according to the embodiment of the present invention includes a cover member 110 having a first electrode formed on a lower surface thereof, and a body portion 100 having a second electrode disposed thereon. And, it comprises a bonding member 120 for coupling the body portion 100 and the cover member 110.

The cover member 110 is preferably manufactured in the form of a disk, and serves to deform under mechanical energy, that is, pressure. At this time, the first electrode 150 formed in a predetermined region of the lower surface of the cover member 110 is also deformed. The cover member 110 has the same diameter as the body 100, it is preferably made of sapphire (Al2O3).

The first electrode 150 may be formed on the bottom surface of the cover member 110, may be manufactured in a plate shape, and then adhered to the bottom surface of the cover member 110 or may be formed by a conventional deposition method. The first electrode 150 is disposed to face the second electrodes 140b and 140c to be described later.

The first electrode 150 and the second electrodes 140b and 140c are configured to have an interval of about 10 to 100 μm. The first electrode 150 and the second electrodes 140b and 140c are preferably formed of Cu, and a metallic material including a conductive material, for example, Ag, Au, Ni, Ta, Ti, Pt, or the like. It is also possible to use.

On the other hand, the body portion 100 serves as a pressure sensor main body, and the second electrodes 140b and 140c and the conducting electrode 140a are disposed at an upper side thereof. The body portion 100 is preferably configured in the form of a disc using a ceramic material, but is not necessarily limited to such material and shape.

The body part 100 is provided with mounting grooves 145b and 145c into which the second electrodes 140b and 140c are inserted and a mounting groove 145a into which the conducting electrode 140a is inserted. In addition, a vent hole 220 for maintaining the internal pressure of the pressure sensor equal to the external air pressure is also formed.

The second electrodes 140b and 140c and the conducting electrode 140a inserted into the mounting grooves 145a, 145b, and 145c of the body part 100 are separately manufactured in a plate shape.

The second electrodes 140b and 140c and the conducting electrode 140a may be formed of Cu. In addition, the second electrodes 140b and 140c may be formed using a metal material such as Ag, Au, Ni, Ta, Ti, or Pt.

As described above, the second electrodes 140b and 140c may be inserted into the mounting grooves 145b and 145c, thereby designing the height of the electrode assembly 122 except for the heights of the second electrodes 140b and 140c. For this reason, the usage-amount of the expensive electrode assembly 122 can be reduced significantly.

The electrode assembly 122 is positioned between the body part 100 and the second electrodes 140b and 140c, and between the body part 100 and the conducting electrode 140a, so that the body part 100 and the second electrode ( 140b and 140c and the energizing electrode 140a are joined together.

The electrode assembly 122 is made of a conductive composition containing an active metal (Ti, Zr, etc.). In this embodiment, a bonding material having 59 wt% Ag, 27.2 wt% Cu, 12.5 wt% In, and 1.25 wt% Ti is used. As described above, the electrode assembly 122 including the active metal is formed in the same shape as the second electrodes 140b and 140c and the conducting electrode 140a, but is manufactured in the form of a thin plate, and the body portion 100 is seated. It is inserted into the grooves 145a, 145b, and 145c. Accordingly, the electrode assembly 122 is heated and melted between the body portion 100 and the second electrodes 140b and 140c and between the body portion 100 and the conducting electrode 140a to form a junction portion.

In addition, contact holes 210a, 210b and 210c are formed in the body part 100 and penetrate through the body part 100, and connection terminals 200a and 210b may be formed in the contact holes 210a, 210b and 210c, respectively. 200b and 200c are provided.

In addition, the connection terminals 200a, 200b, and 200c may use wires or lead wires of conductive rods, and pastes 201a, 201b, 201c and conductive metal powder made of a conductive metal material. Can be used as the electrical connection terminals 200a, 200b, and 200c by filling the contact holes 210a, 210b, and 210c and curing them.

  At this time, one end of the connection terminal (200a, 200b, 200c) that is located outside the body portion 100 is connected to an external power source (not shown), the connection terminal 200a, which is inserted into the body portion 100, The other ends of the 200b and 200c are electrically connected to the second electrodes 140b and 140c and the conducting electrode 140a of the upper portion of the body, respectively.

The paste may be composed of, for example, a conductive filler, an organic binder, glass frits, or the like. The conductive filler may be selected from powders such as Ag, Au, Cu, Al, and the organic binder may be selected from thermosetting resins such as epoxy resins, copolyesters, phenol resins, and polyurethanes.

In addition, the conductive metal powder may be selected from metals such as Ag and Pt.

The energizing electrode of 140a is electrically connected to the first electrode 150 by a conductive bonding member 120.

According to the configuration as described above, when power is applied to each of the plurality of connection terminals 200a, 200b, 200c by using an external power source (not shown), the second electrode of the upper portion of the body by the connection terminal 210 ( Power is applied to the 140b and 140c and the conducting electrode 140a to drive the capacitive pressure sensor.

On the other hand, the bonding member 120 is formed in a ring shape is disposed around the outer periphery of the first electrode 150 and the second electrode (140b, 140c), located between the body portion 100 and the cover member 110 The body portion 100 and the cover member 110 are bonded to each other.

The bonding member 120 is preferably made of an active metal composition containing an active metal (Ti, Zr, etc.), in this embodiment Ag 63.5% by weight, Cu 34.2% by weight, Sn 1% by weight, Ti 1.75% by weight The filler metal made up of% is used. The composition containing the active metal may be a conjugate having a strong bonding force through a covalent bond with the ceramic material (alumina). The bonding member 120 is manufactured in the form of a thin plate of a ring structure, and is located in the edge region of the body part 100 and the cover member 110.

Next, a process of manufacturing a capacitive pressure sensor according to an embodiment of the present invention will be described with reference to FIGS. 6 and 7.

First, a method of manufacturing the body part 100 provided with the second electrodes 140b and 140c will be described.

As shown in FIG. 6A, mounting grooves 145b and 145c into which the second electrodes 140b and 140c are inserted, and mounting grooves 145a into which the conducting electrode 140a is inserted are formed, and contact holes 210a and 210b, 210c and 210c are not shown due to the cross-sectional position of FIG. 6 in which the AA 'portion is cut, but the position thereof may be confirmed in FIG. 5).

In the mounting grooves 145a, 145b, and 145c of the body portion 100, the electrode assemblies 122a and 122b of a thin plate are formed to bond the second electrodes 140b and 140c and the conducting electrode 140a to the body portion 100. 122c) is inserted first.

After the electrode assemblies 122a, 122b, and 122c are inserted, as shown in FIG. 6 (b), the second electrodes 140b and 140c and the conducting electrode 140a are prepared, and the mounting grooves 145a, 145b, 145c).

Thereafter, heat is applied to melt the electrode assembly 122 so that the second electrodes 140b and 140c and the conducting electrode 140a are fixed to the mounting grooves 145a, 145b, and 145c of the body portion 100.

Next, as shown in Figure 7 (c), the lead wires (202a, 202b, 202c; 202c in the state in which the body portion 100 is upside down is not shown due to the cross-sectional position of Figure 7 but to confirm the position in Figure 5 Can be inserted into the contact holes 210a, 210b, and 210c, respectively.

Subsequently, as shown in FIG. 7 (d), the conductive pastes 201a, 201b and 201c are filled in the contact holes 210a, 210b and 210c to form the connection terminals 200a, 200b and 200c. And heat. Accordingly, the conductive pastes 201a, 201b, and 201c fix the lead wires 202a, 202b, and 202c, and the pastes 201a, 201b, and 201c provide the electrode assembly 122 and the lead wires 202a, 202b, It also serves as an electrical connector between 202c). The conductive paste may be replaced with a conductive metal powder.

After completing the above process, the main body 100 has an annular joining member 120 disposed on the upper outer side as shown in FIG. 11, and then is joined to the cover member 110 by placing the cover member 110 thereon.

In the bonding process, the body member 100 and the cover member 110 are bonded by applying heat to the bonding member 120.

The material of the bonding material is selected so that the heating temperature of the bonding material sequentially made in the manufacturing process is sequentially lowered than the heating temperature of the previous step. For example, in the manufacturing process, the temperature decreases in the order of the junction temperature of the electrode assemblies 122a, 122b, and 122c, the curing temperature of the pastes 201a, 201b, and 201c, and the junction temperature of the junction member 120. This is to prevent damage to other joints already completed in the subsequent heating process.

8 illustrates a method different from the method in which the connection terminals 200a, 200b, and 200c are formed in FIG.

Referring to FIG. 8, the method does not insert separate lead wires 202a, 202b, and 202c into contact holes 210a, 210b, and 210c, and only conductive pastes 201a, 201b, and 201c are filled. By hardening, it functions as a connection terminal.

According to the method, the electrode assemblies 122a, 122b and 122c and the external circuit portion (not shown) are electrically connected to the connection terminal made of the conductive paste. The conductive paste may be replaced with a conductive metal powder.

In addition, FIG. 9 illustrates a method different from that of the connection terminals 200a, 200b, and 200c in FIGS. 7 and 8.

Referring to FIG. 9, in the present method, lead wires 202a, 202b, and 202c are inserted into the connection terminals to be bonded to the electrode assemblies 122a, 122b, and 122c by soldering or welding, respectively. At this time, the tool for soldering or welding is inserted into the space between the lead wires (202a, 202b, 202c) and the walls of the contact holes (210a, 210b, 210c) is performed.

On the other hand, the formation method of another connection terminal (200a, 200b, 200c) can be configured as follows.

As shown in FIG. 10, before the electrode assemblies 122a, 122b and 122c are heated, the contact wires 210a, 202b and 202c are in contact with the electrode assemblies 122a, 122b and 122c. ) Is inserted. Thereafter, the electrode assemblies 122a, 122b and 122c are heated to bond the second electrodes 140b and 140c and the conducting electrode 140a to the body part 100 by the electrode assemblies 122a, 122b and 122c. In addition, the lead terminals 202a, 202b, and 202c are simultaneously joined to form connection terminals 200a, 200b, and 200c.

On the other hand, the formation method of another connection terminal (200a, 200b, 200c) can be configured as follows. The conductive paste is filled in the contact holes 210a, 210b and 210c before the electrode assemblies 122a, 122b and 122c are heated. In this case, lead wires 202a, 202b, and 202c may be selectively installed in the contact holes 210a, 210b, and 210c as necessary. Subsequently, heat is applied to the electrode assemblies 122a, 122b and 122c and the conductive paste to fix the second electrodes 140b and 140c and the conducting electrode 140a to the body and to cure the paste. Accordingly, the number of processes may be reduced by fixing the second electrodes 140b and 140c and the conducting electrode 140a and forming the connection terminals 200a, 200b and 200c by one heating process. Of course, in this process, it may be considered to replace the paste with a metal powder.

Thereafter, the main body 100 manufactured by one of the above methods is bonded to the cover member 110 as shown in FIG. 11.

The joining operation is performed by arranging the annular joining member 120 at its edge and then placing and heating the cover member 110 thereon. At this time, the first electrode 150 is formed on the lower surface of the cover member 110 in advance. The first electrode 150 may be sputter deposited using a conventional method or may be separately manufactured and attached in a thin film form.

In addition, when the body portion 100 and the cover member 110 are bonded to each other, the first electrode 150 formed on the lower surface of the cover member 110 is electrically connected to the conductive bonding member 120 by bonding to the conductive member 120. Accordingly, the first electrode 150 may be electrically connected to the connection terminal 200a through the conducting electrode 140a.

12 shows a state in which the cover member 110 of the pressure sensor according to the present invention is deformed under pressure.

The cover member 110 is deformed together with the first electrode 150 under pressure from the upper side. As a result, an internal capacitance between the second electrode 140b and the first electrode 150 in the inner side and an electrostatic capacitance outside the second electrode 140b and 140c and the first electrode 150 in the outer side. There is a difference in capacity. This is because the inner part is closer to the main body 100 than the outer part when the cover member 110 is deformed, so a difference occurs in the gaps L1 and L2 of both parts.

Accordingly, since the difference between the capacitance of the inner side and the outer side varies with the pressure, the magnitude of the pressure is calculated using the difference.

While the above has been shown and described with respect to preferred embodiments and applications of the present invention, the present invention is not limited to the specific embodiments and applications described above, the invention without departing from the gist of the invention claimed in the claims Various modifications are possible by those skilled in the art.

100; Body 110; Cover member
120; Joining members 122a, 122b, 122c; Electrode assembly
140a; Conducting electrodes 140b and 140c; Second electrode
145a, 145b, 145c; Seating groove 150; First electrode
200a, 200b, 200c; Connection terminals 201a and 201b; Paste
202a, 202b, 202c; Lead wires 210a, 210b, and 210c; Contact hole
220; Ventilation hole

Claims (13)

A cover member having a first electrode formed thereon;
A body part installed below the cover member and provided with a second electrode facing the first electrode at a predetermined interval;
In the capacitive pressure sensor comprising a bonding member for bonding both between the cover member and the body portion,
A seating groove is formed in the body portion,
The second electrode is inserted into and fixed to the seating groove,
Capacitive pressure sensor, characterized in that the contact hole is formed in the lower side of the seating groove is provided with a connection terminal electrically connected to the second electrode The method of claim 1,
The second electrode is capacitive pressure sensor, characterized in that fixed to the seating groove by a conductive electrode assembly inserted into the lower side The method of claim 2,
The connection terminal is a capacitive pressure sensor, characterized in that electrically connected with the second electrode through the electrode assembly. 4. The method according to any one of claims 1 to 3,
The second electrode is divided into an inner and an outer electrode,
The seating grooves are capacitive pressure sensors, characterized in that formed to correspond to the inner and outer electrodes, respectively. In the method of manufacturing the body portion of the capacitive pressure sensor,
Preparing a body part having a contact hole formed at a lower side of the seating groove into which an electrode is inserted and the seating groove;
Sequentially inserting a conductive electrode assembly and an electrode into the seating groove;
And installing a connection terminal in the contact hole to electrically connect with the electrode after the electrode assembly and the electrode are inserted. The method of claim 5,
After the step of inserting the electrode assembly and the electrode, heating the electrode assembly to fix the electrode to the body portion; manufacturing method of the body portion of the capacitive pressure sensor further comprises a. The method of claim 5,
In the step of installing the connection terminal
Method for manufacturing a body portion of the capacitive pressure sensor, characterized in that for electrically heating the electrode assembly and the connection terminal at the same time to electrically connect the electrode and the connection terminal. The method according to any one of claims 5 to 7,
Installing the connection terminal,
A method of manufacturing a capacitive pressure sensor, comprising the step of filling the contact hole with a conductive paste or a conductive metal powder, and heating and curing the contact hole. A cover member having a first electrode formed thereon;
A body part installed below the cover member and provided with a second electrode facing the first electrode at a predetermined interval;
In the manufacturing method of the capacitive pressure sensor comprising a bonding member for bonding both between the cover member and the body portion,
Preparing a mounting portion into which the second electrode is inserted and a body portion having a contact hole formed under the mounting groove;
Sequentially inserting a conductive electrode assembly and the second electrode into the seating groove;
Installing a connection terminal in the contact hole to be electrically connected to the second electrode after the second electrode is inserted into the seating groove; And
And joining the cover member and the body portion with the joining member such that the second electrode faces the first electrode at a predetermined interval. 10. The method of claim 9,
After the step of inserting the electrode assembly and the second electrode,
And heating the electrode assembly to fix the second electrode to the body part. The method of claim 9 or 10,
Installing the connection terminal,
A method of manufacturing a capacitive pressure sensor, comprising the step of filling the contact hole with a conductive paste or a conductive metal powder, and heating and curing the contact hole. 10. The method of claim 9,
Installing the connection terminal,
Filling the contact hole with a conductive paste or a conductive metal powder,
And simultaneously heating the paste or the metal powder and the electrode assembly to fix the second electrode to the body and to cure the paste or the metal powder. 10. The method of claim 9,
Installing the connection terminal,
The method of manufacturing a capacitive pressure sensor, characterized in that the electrode assembly is heated to bond the second electrode to the connection terminal and the body at the same time.

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