JP7628863B2 - Sensor Device - Google Patents

Description

The present invention relates to a sensor device such as a diaphragm vacuum gauge.

Patent Document 1 discloses a sensor device that includes a sensor unit (sensor 2 and heater H) that has a metal housing and includes a sensor that is heated by a heater, a sensor case (inner case 42 and the lower part of outer case 41) that houses the sensor unit, a circuit board (boards 31a to 31c) that is mounted with a connector (connector 4p) to which a cable is connected, and a board case (inner case 42 and the upper part of outer case 41) that houses the circuit board.

JP 2007-155500 A

In the sensor device described in Patent Document 1, if it is necessary to supply the potential (e.g., reference potential) of the mounting object (such as the piping of a semiconductor manufacturing device) on which the sensor device is mounted to the connector, it is necessary to form the board case and the sensor case from metal and electrically connect the connector to the mounting object via these cases. However, in this case, the entire case is made of metal, which increases manufacturing costs.

The objective of the present invention is to supply the electrical potential of the object to be attached to the connector while making the board case out of synthetic resin.

In order to solve the above problems, the sensor device according to the present invention is a sensor device that is attached to an object to be attached and used, and includes a sensor unit including a sensor heated by a heater and having a metal housing attached to the object, a sensor case that houses the sensor unit, a circuit board on which a connector to which a cable is connected is mounted, and a board case that houses the circuit board, the board case being made of synthetic resin, the sensor case having a metal case that is electrically connected to the circuit board and in contact with the housing, and the circuit board being wired to supply the potential supplied from the sensor housing via the metal case to the connector.

The metal case may be configured to have a shape having a first conduction path that conducts the heat in a first direction and a second conduction path that conducts the heat in a second direction different from the first direction, so that the conduction path from the housing to the electrical connection with the circuit board is long.

The metal case may be formed in a mesh pattern.

The device may further include a connection member that electrically connects the metal case and the circuit board, and the connection member may be connected to the board case.

According to the present invention, the board case is made of synthetic resin, and the potential of the attachment object is supplied to the connector.

FIG. 1 is a cross-sectional view of a main part of a sensor device according to an embodiment of the present invention. FIG. 2 is a perspective view and a partially enlarged view of the sensor device with a part of the board case removed. FIG. 3 is an enlarged cross-sectional view of a connection member and the like. FIG. 4 is a perspective view showing a supply path of the reference potential. FIG. 5 is a perspective view of the outer case. 6A to 6C are diagrams showing examples of shape patterns of outer cases according to modified examples.

The following describes a sensor device according to an embodiment of the present invention with reference to the drawings. Note that in this embodiment, up, down, left and right directions are set, but the up and down directions do not have to coincide with the top and bottom directions depending on the installation direction of the sensor device.

As shown in FIG. 1, the sensor device 10 according to this embodiment is connected to a pipe H (mounting object) connected to a vacuum chamber T in a semiconductor control device or the like via a joint (not shown), and is configured as a diaphragm vacuum gauge that measures the air pressure of the process gas introduced from the vacuum chamber T to the pipe H.

The sensor device 10 includes a sensor unit 20, a heat insulating unit 30, a circuit board 40, and a case 50. The sensor device 10 also includes wiring L1 to L3 that electrically connects the sensor unit 20 and the circuit board 40. Note that in FIG. 1, the wiring L1 to L3 are depicted as an elevation view rather than a cross-sectional view.

The sensor unit 20 includes a pressure sensor 21, a terminal board 22, a heater 25, a heater support member 26, and a temperature sensor 27.

The pressure sensor 21 includes a vacuum chamber R1 and an inflow chamber R2 into which the process gas in the pipe H flows in, inside the housing 21A. The housing 21A is made of metal, and its lower part is configured to be connected to the pipe H via a joint. The pressure sensor 21 detects the air pressure of the process gas. Specifically, the pressure sensor 21 includes a sensor element 21B (schematically drawn as a block in FIG. 1 and the like) disposed at the boundary between the vacuum chamber R1 and the inflow chamber R2, and a conductive pin 21C connected to the sensor element 21B. The sensor element 21B has a diaphragm (diaphragm) that deforms according to the differential pressure between the vacuum chamber R1 and the inflow chamber R2. The sensor element 21B detects the air pressure of the process gas based on the air pressure of the vacuum chamber R1 by outputting an electrical signal indicating a resistance value or electrostatic capacitance value according to the degree of deformation of the diaphragm. The conductive pin 21C penetrates the housing 21A and transmits the electrical signal output by the sensor element 21B to the outside of the housing 21A.

The conductive pin 21C is electrically connected to the wiring L1, which is a coaxial cable, via a conductive terminal plate 22. The connection between the terminal plate 22 and the conductive pin 21C, and between the terminal plate 22 and the wiring L1 are performed by welding or the like. A cylindrical shield may be provided to surround the conductive pin 21C and connected to the outer conductor of the coaxial cable, so that the signal potential of the conductive pin 21C and the like is not affected by the potential of the metal housing 21A of the pressure sensor 21. Although the number of conductive pins 21C and wiring L1 is one in FIG. 1, there may be two or more.

The heater 25 heats the pressure sensor 21 to prevent the process gas from precipitating inside the pressure sensor 21. The heater 25 is a cylindrical band heater (the internal structure is omitted in FIG. 1) and is fastened to a cylindrical heater support member 26. This fastening allows the heater support member 26 to support the heater 25. Power is supplied to the heater 25 from the circuit board 40 via the wiring L2. This power supply causes the heater 25 to generate heat. The heater support member 26 has an annular protrusion 26A that protrudes inward. The protrusion 26A engages with a step on the outer periphery of the pressure sensor 21. This engagement allows the heater support member 26 to be supported by the pressure sensor 21 together with the heater 25.

The temperature sensor 27 is in contact with the pressure sensor 21 and detects the temperature of the pressure sensor 21 heated by the heater 25. The internal structure of the temperature sensor 27 is omitted in FIG. 1. The temperature sensor 27 outputs the detected temperature to the circuit board 40 via the wiring L3.

The heat insulating section 30 comprises a cylindrical heat insulating material 31 that surrounds the sensor section 20, and a disk-shaped heat insulating material 32 that is disposed above the sensor section 20. The heat insulating section 30 as a whole covers the sensor section 20 from above, and insulates against heat from the pressure sensor 21 or the heater 25 so that the heat does not adversely affect the circuit board 40, etc. The heat insulating materials 31 and 32 are made of any material that has a heat insulating effect. The heat insulating material 32 prevents heat from the pressure sensor 21, etc. from moving upward.

The circuit board 40 is constructed by assembling a number of boards. Circuits (including a microcomputer, etc.) that perform various processes are mounted on the circuit board 40. The circuit board 40 has a connector 41 to which a cable (not shown) is connected that is used when the sensor device 10 communicates with an external device such as a higher-level device (e.g., a controller for a semiconductor manufacturing device, etc.). The circuit board 40 is configured to supply the potential of the pipe H, to which the sensor device 10 is attached, to this connector 41. Here, the potential of the pipe H will be described as the reference potential. The reference potential supplied to the connector 41 is conducted to a connector that supplies the potential to the connector 41, for example.

Wires L1 to L3 are connected to the circuit board 40. For example, when the sensor element 21B is a capacitive type, the circuit board 40 applies an AC voltage to the sensor element 21B through one of the multiple wires L1. Furthermore, the circuit board 40 acquires a voltage signal that changes according to the capacitance value of the capacitor formed by the sensor element 21B through one of the multiple wires L1. As a result, the electrical signal output by the sensor element 21B and extracted by the conductive pin 21C is transmitted by the wire L1 and supplied to the circuit board 40. The circuit board 40 performs processing based on the acquired electrical signal. For example, the circuit board 40 amplifies the electrical signal, converts it from analog to digital, etc., to obtain data in a predetermined format that represents the air pressure of the process gas indicated by the electrical signal. The obtained data is output to an external device through the connector 41 and a cable. The circuit board 40 receives the temperature output from the temperature sensor 27 through the wire L3, and controls the power supplied to the heater 25 through the wire L2 using the temperature as a feedback value so that the pressure sensor 21 reaches the desired temperature (for example, 200°C). As described above, the circuit board 40 controls the sensor unit 20 via the wiring L1 to L3.

The case 50 houses the sensor unit 20, the heat insulating unit 30, the circuit board 40, and the wiring L1 to L3. The case 50 includes a sensor case 51 that houses the sensor unit 20 and the heat insulating unit 30, and a board case 56 that houses the circuit board 40.

The sensor case 51 is provided with a cylindrical inner case 52 having a thickness in the radial direction as a whole, and a cup-shaped outer case 53 that covers the inner case 52 from the outside. The inner case 52 is composed of an upper inner case 52A having an annular shape with an inverted U-shaped cross section, and a cup-shaped lower inner case 52B with a through hole in the center. The inner case 52 houses a cylindrical insulating material 31 inside. The disk-shaped insulating material 32 is housed in the upper inner case 52A. The insulating material 32 is flexible, and presses the wiring L1 to L3 passing through the upper inner case 52A against the inner surface 52AA of the upper inner case 52A. The inner case 52 is made of synthetic resin so as not to inhibit the insulating effect of the insulating material 31. The outer case 53 is made of metal, and its lower part is in contact with the housing 21A of the pressure sensor 21. Details of the outer case 53 will be described later. The sensor case 51 has an overall cup shape with a through hole in the center of the bottom, and the opening at the top is covered with a thermal insulator 32.

The board case 56 is made of synthetic resin (engineering plastic, super engineering plastic, etc.). The board case 56 covers the sensor case 51 so that the connector 41 can be exposed to the outside. The board case 56 may have a through hole for cooling the circuit board 40.

Here, the relationship between the circuit board 40, the outer case (metal case) 53, and the board case 56 will be described. As shown in FIG. 2, the sensor device 10 further includes a cylindrical connection member 90 that connects the circuit board 40 and the outer case 53. The connection member 90 includes a cylindrical portion 91 and screws 92 and 93. The fixing portion 56F of the board case 56 (omitted in the enlarged view surrounded by the dashed line in FIG. 2) is fixed to the cylindrical portion 91 in a state in which the cylindrical portion 91 penetrates the fixing portion 56F. As a result, the outer case 53 is fixed to the board case 56 via the connection member 90 together with the inner case 52 and the sensor unit 20 housed in the outer case 53, and the circuit board 40 is also fixed. The connection members 90 are arranged at each of the four corners of the sensor device 10, and the above-mentioned connection and fixing are performed at each of the four corners.

As shown in FIG. 3, the cylindrical portion 91 has an inner tube 91A made of metal and an outer tube 91B made of synthetic resin. The inner tube 91A and the outer tube 91B are integrally formed by insert molding or the like. The screws 92 and 93 are made of metal. The screw 92 passes through a hole formed in the circuit board 40 and screws into the inner tube 91A of the cylindrical portion 91, thereby tightening and fixing the circuit board 40 to the cylindrical portion 91. The screw 93 passes through a notch formed in the outer case 53 (a portion protruding from the upper end of the cylindrical portion toward the outer periphery) and screws into the inner tube 91A of the cylindrical portion 91, thereby tightening and fixing the outer case 53 to the cylindrical portion 91. A wiring L11 (see also FIG. 2) connected to the connector 41 is routed around the portion of the circuit board 40 that contacts the screw 92. The wiring L11 is printed on the circuit board 40. As described above, the connector 41 is electrically connected to the outer case 53 via the circuit board 40 (wire L11) and the connection member 90 (inner tube 91A, screw 92, and screw 93) (FIGS. 2 and 3). As shown in FIG. 1, the outer case 53 is in contact with the metal housing 21A of the pressure sensor 21. As described above, the housing 21A is connected to the pipe H. Therefore, as shown by the bold line in FIG. 4, the reference potential of the pipe H is supplied to the connector 41 via the path of the pipe H → housing 21A → outer case 53 → connection member 90 → circuit board 40 → connector 41.

As described above, according to this embodiment, the circuit board case 56 is made of synthetic resin to reduce costs, but the sensor case 5 includes a metal outer case 53 electrically connected to the circuit board 40 and in contact with the housing 21A of the pressure sensor 21, and the circuit board 40 is wired by the wiring L11 to supply the potential supplied from the housing 21A of the pressure sensor 21 via the outer case 53 to the connector 41. Therefore, while the circuit board case 56 is made of synthetic resin, the potential of the object to which the sensor device 10 is attached (here, the piping H) can be supplied to the connector 41. The outer case 53 and the circuit board 40 may be directly connected by welding, etc., but it is easier to electrically connect the two using a part such as the connection member 90.

The outer case 53 contacts the housing 21A of the pressure sensor 21, and as described above, the pressure sensor 21 is heated by the heater 25 (for example, heated to 200°C). This heating also heats the housing 21A, and the heat of the housing 21A is transferred to the outer case 53. The outer case 53 is made of metal to supply the above-mentioned potential to the connector 41, so depending on its shape, it is easy to transfer the heat transferred from the housing 21A to the connection member 90, etc. Therefore, in this embodiment, the outer case 53 is made of a mesh shape as shown in Figure 2, and the heat conduction path from the contact part of the outer case 53 with the housing 21A to the connection member 90 (electrical connection part with the circuit board 40) is lengthened. Specifically, in order to lengthen the heat conduction path, the outer case 53 is formed in a shape in which the heat conducting portion is bent and branched from a thin rod shape, as shown in FIG. 5, and is particularly formed in a shape having a first conduction path M1 that conducts heat in a first direction and a second conduction path M2 that conducts heat in a second direction different from the first direction. In this way, by lengthening the heat conduction path, the heat is gradually cooled in the process of being transmitted through the outer case 53, and adverse effects (deformation, etc.) on the connection member 90 and the circuit board 40 and board case 56 connected to the connection member 90 are suppressed.

The mesh shape may have one or more repetitions of the patterns in Figures 6(A) and (B), for example. This also makes it possible to lengthen the heat conduction path. The outer case 53 may have one or more repetitions of the pattern in Figure 6(C). In this pattern, heat can be conducted in a straight line from below diagonally upward, but depending on the positioning of the start and end points of the heat conduction path, the heat conduction path can be made longer.

Furthermore, in the above embodiment, the connection member 90 is used to supply the reference potential to the connector 41 and to fix the outer case 53, the circuit board 40, and the board case 56 to each other, thereby achieving effects such as reducing the number of parts of the sensor device 10 and reducing costs.

The above embodiment can be modified in various ways. For example, the shapes of the components described above are arbitrary. The cylinders and disks described above can be changed to polygonal tubes, polygonal plates, etc. The heater 25 may be provided separately from the sensor device 10 and attached from the outside of the sensor device 10 to heat the pressure sensor 21. The connection destination of the wiring connecting the sensor unit 20 and the circuit board 40 on the sensor unit 20 side can be changed depending on what components the sensor unit 20 has, and is not limited to the above embodiment. The present invention can be applied to sensor devices other than diaphragm vacuum gauges. The sensor device to which the present invention is applied may be a device that measures a physical quantity other than pressure.

Although the present invention has been described above with reference to the embodiments and modifications, the present invention is not limited to the above-mentioned embodiments and modifications. For example, the present invention includes various modifications to the above-mentioned embodiments and modifications that can be understood by a person skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above-mentioned embodiments and modifications can be combined as appropriate within a range that does not cause inconsistencies.

10...sensor device, 20...sensor section, 21...pressure sensor, 21A...housing, 21B...sensor element, 21C...conductive pin, 22...terminal board, 25...heater, 27...temperature sensor, 30...insulating section, 31...insulating material, 32...insulating material, 40...circuit board, 41...connector, 50...case, 51...sensor case, 52...inner case, 52A...upper inner case, 52B...lower inner case, 53...outer case, 56...circuit board case, 56F...fixing section, 90...connecting member, 91...cylindrical section, 91A...inner tube, 91B...outer tube, 92, 93...screw, M1...first conductive path, M2...second conductive path, H...piping.

Claims (4)

A sensor device that is attached to an object to be attached,
a sensor unit including a sensor that is provided with a metal housing that is attached to the attachment target and is heated by a heater;
A sensor case that houses the sensor unit;
A circuit board on which a connector to which a cable is connected is mounted;
a board case that houses the circuit board,
the substrate case is made of synthetic resin,
the sensor case includes a metal case electrically connected to the circuit board and in contact with the housing;
The circuit board is wired to supply a potential supplied from the housing of the sensor through the metal case to the connector.
Sensor device. The metal case is configured to have a shape having a first conduction path that conducts the heat in a first direction and a second conduction path that conducts the heat in a second direction different from the first direction, so that a heat conduction path from the housing to an electrical connection part with the circuit board is long.
The sensor device according to claim 1 . The metal case is formed in a mesh shape.
The sensor device according to claim 2 . a connecting member electrically connecting the metal case and the circuit board;
The connection member is fixed to the board case.
The sensor device according to claim 1 .

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