JP5969351B2 - Pressure sensor parts - Google Patents

Description

  The present invention relates to a capacitance type pressure sensor component for detecting pressure.

  Conventionally, a capacitance-type pressure detection device has been used as a pressure sensor for detecting pressure. As a pressure sensor component used in the capacitance type pressure sensor, a predetermined space is provided between the insulating substrate having the first electrode for forming the capacitance on the surface and the insulating substrate. A diaphragm having a second electrode for forming a capacitance which is bonded to the surface of the insulating substrate in a flexible state and is opposed to the first electrode, and is provided between the insulating substrate and the diaphragm. A device having a spacer is known. In such a pressure sensor component, an insulating substrate, a diaphragm, and a spacer are integrally formed, and thereby an internal space sealed in an insulating base is formed. In such a pressure sensor, when the diaphragm bends due to an external pressure fluctuation, the distance between the first electrode and the second electrode changes and the capacitance between them changes. The change in pressure can be detected by the change (see, for example, Patent Document 1).

JP 2006-47327 A

  In order to protect or fix the pressure sensor, the pressure sensor may be covered with a rubber or resin coating member. However, when a part of the covering member covering such a pressure sensor comes into contact with the flexible part, the flexible part is deformed or the way of bending due to the pressure is changed, and the external pressure is accurately measured. It had the problem that it could not be done.

A pressure sensor component according to an aspect of the present invention includes: a base portion; a frame portion provided on the base portion; a flexible portion provided above the base portion and inside the frame portion; , frame portion, and an insulating substrate having an inner space surrounded by the flexible portion, so as to sandwich the inner space, and a plurality of electrodes provided on the insulating base, the frame portion from the flexible portion Also has an upper end portion located above, and the upper end portion extends toward the center of the flexible portion in a plan view, and the upper end portion is flexible toward the center portion of the flexible portion in a cross-sectional view. It is inclined to approach the part .

A pressure sensor component according to an aspect of the present invention includes: a base portion; a frame portion provided on the base portion; a flexible portion provided above the base portion and inside the frame portion; Enclosed in frame, flexible part
An insulating base having an inner space and a plurality of electrodes provided on the insulating base so as to sandwich the inner space, and an upper end portion where the frame portion is positioned above the flexible portion. The upper end portion extends toward the center of the flexible portion in plan view, and the upper end portion is inclined so as to approach the flexible portion toward the center portion of the flexible portion in cross-sectional view. Therefore, the flexible part is protected by the upper end part, and the possibility that a covering member made of, for example, rubber or resin arranged on the upper end part contacts the flexible part can be reduced, and the external pressure can be accurately applied. It can be detected.

(A) is a top view which shows the components for pressure sensors in the 1st Embodiment of this invention, (b) is sectional drawing in the AA of (a). It is a top view which shows the components for pressure sensors in the 2nd Embodiment of this invention. (A) is sectional drawing in the AA of the pressure sensor components shown by FIG. 2, (b) is an enlarged view in the A section of (a). (A) is sectional drawing which shows the components for pressure sensors in the 3rd Embodiment of this invention, (b) is an enlarged view in the A section of (a). (A) is a top view which shows the components for pressure sensors in the 4th Embodiment of this invention, (b) is sectional drawing in the AA of (a).

  Several exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
As in the example shown in FIG. 1, in the pressure sensor component according to the first embodiment of the present invention, the insulating base 1 includes a base 2, a frame 3 provided on the base 2, and a base 2 and a flexible portion 4 provided inside the frame portion 3. The insulating base 1 has an internal space 5 surrounded by the base 2, the frame 3, and the flexible part 4. A plurality of electrodes 6 are provided so as to sandwich the internal space 5. The frame portion 3 has an upper end portion 31 positioned above the flexible region 4, and the upper end portion 31 has an extending portion 31 a that extends toward the center of the flexible portion 4. In the pressure sensor component according to the present embodiment, the upper end portion 31 and the side surface of the insulating substrate 1 are covered with the covering member 11 as in the example shown in FIG.

  The insulating base 1 is formed in a square shape in plan view, and the inner diameter and the flexible portion 4 of the frame portion 3 and the internal space 5 are formed in a circular shape in plan view. A wiring conductor 7 electrically connected to the electrode 6 is formed inside and on the surface of the insulating base 1.

  The insulating substrate 1 is an electrically insulating sintered body such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon carbide sintered body, a silicon nitride sintered body, or a glass ceramic. For example, as in the example shown in FIG. 1, the internal space 5 is formed by laminating a plurality of insulating layers.

  If the insulating base 1 is made of, for example, an aluminum oxide sintered body, it is manufactured as follows. First, a ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide is mixed with a suitable organic binder, solvent, plasticizer, and dispersant to form a slurry, and this is formed into a sheet by the doctor blade method. To obtain a plurality of ceramic green sheets. A ceramic green sheet for the insulating substrate 1 is obtained by subjecting these ceramic green sheets to appropriate punching and cutting. At this time, in some of the ceramic green sheets for the frame portion 3, a through hole serving as the internal space 5 is formed by a hole processing method such as punching by a die or punching or laser processing. By laminating these ceramic green sheets, a ceramic green sheet laminate for the insulating substrate 1 having the internal space 5 is formed. Then, by firing this ceramic green sheet laminate at a temperature of about 1600 ° C., an insulating substrate 1 having an internal space 5 surrounded by the substrate portion 2, the frame portion 3 and the flexible portion 4 is manufactured.

  Since the upper end portion 31 is positioned above the flexible portion 4, the region to be the flexible portion 4 of the ceramic green sheet laminate for the insulating substrate 1 before firing or the flexible portion of the pressure sensor component after firing. 4 is reduced from hitting an external object, and the possibility that the relatively thin flexible part 4 is damaged can be reduced. The upper end portion 31 has a hole 3b in the central portion of the extending portion 31a. Since the upper end portion 31 has the hole 3b, external pressure can be applied to the flexible portion 4.

Electrodes 6 facing each other are formed on the lower surface of the flexible portion 4 and the upper surface of the base portion 2 that face each other across the internal space 5. The electrode 6 is an electrode for forming a capacitance. Between the electrodes 6 facing each other, a capacitance is formed according to the facing area and interval between the electrodes 6 facing each other. For example, in the example shown in FIG. 1, when a pressure is applied to the insulating substrate 1 from the outside, the flexible portion 4 is bent toward the inner space 5 according to the pressure, and the interval between the electrodes 6 facing each other is It becomes smaller than before the pressure is applied, and the capacitance between the electrodes 6 increases. The pressure sensor can detect a change in external pressure as a change in capacitance by detecting such a change in capacitance. When the pressure is greatly reduced, the flexible portion 4 is deflected to the opposite side to the internal space 5 according to the pressure, and the distance between the opposing electrodes 6 is increased, and the electrostatic capacitance between the electrodes 6 is increased. It will be smaller.

  In plan view, the electrode 6 provided on the base portion 2 has a smaller area than the electrode 6 provided on the flexible portion 4 and is disposed so as not to protrude from the electrode 6 on the flexible portion 4 side. Is preferred. When the sizes of the electrodes 6 facing each other in plan view are different from each other, the small electrodes 6 are preferably arranged so as to overlap the entire large electrodes 6. With such a configuration, even when the opposing positions of the electrodes 6 facing each other are shifted when the insulating base 1 is manufactured, it is possible to reduce the reduction of the facing area between the electrodes 6. Further, the rate of change in the distance between the electrodes 6 due to the change in pressure outside the flexible portion 4 is large at the center of the flexible portion 4 and small at the outer periphery of the flexible portion 4. Therefore, if the area of the electrode 6 provided on the base portion 2 is smaller than the area of the electrode 6 provided on the flexible portion 4, the center of the flexible portion 4 where the rate of change of the distance between the electrodes 6 is large. Since the ratio of the area where the electrodes 6 face each other can be improved, the rate of change in capacitance due to a change in external pressure increases, and the sensitivity of the pressure detection device can be increased.

  The wiring conductor 7 is formed on the surface and inside of the insulating base 1, and is electrically connected to the electrodes 6 facing each other, and the change in capacitance between the electrodes 6 is used as an electrical signal to externally. It functions as wiring for transmitting to the circuit board. By transmitting such a change in capacitance to the external circuit board as an electrical signal through the wiring conductor 7 and performing arithmetic processing with an electronic component mounted on the external circuit board, the magnitude of the external pressure is increased. And can detect changes.

  The electrode 6 and the wiring conductor 7 are made of a metallized conductor using a metal powder such as tungsten, molybdenum, copper, or silver. For example, if the insulating substrate 1 is made of an aluminum oxide sintered body, a metallized paste obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, etc. to a metal powder such as tungsten is screen-printed. A predetermined pattern is formed on the surface and inside of the insulating substrate 1 by printing and applying a predetermined pattern on the ceramic green sheet for the insulating substrate 1 by the method, and baking this together with the ceramic green sheet laminate for the insulating substrate 1. Is done. The wiring conductor 7 extending in the vertical direction in the insulating substrate 1 is formed by forming a through hole in the ceramic green sheet and filling the through hole with a metallized paste.

On the surface of the exposed portion of the wiring conductor 7, a metal plating layer having excellent corrosion resistance such as nickel and gold is applied. Corrosion of the wiring conductor 7 can be reduced, and the external circuit board and the wiring conductor 7 can be firmly joined. For example, a nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited on the surface of the exposed portion.

  The frame portion 3 is for providing a predetermined interval between the electrodes 6 facing each other. It has a frame shape having a through hole surrounding the internal space 5. If the thickness of the frame portion 3 is less than 0.01 mm, the distance between the electrodes 6 is relatively small, and therefore the flexible range of the flexible portion 4 is small. Therefore, the range of pressure values that can be measured is relatively small. Get smaller. Further, if the thickness of the frame portion 3 exceeds 5 mm, the distance between the electrodes 6 is relatively large, so that the rate of change of the distance between the electrodes 6 becomes small and the rate of change of the capacitance becomes small. The sensitivity of the sensor is reduced. Therefore, it is preferable that the thickness of the part in which the frame part 3 forms the internal space 5 is 0.01 mm-5 mm.

  The frame part 3 has an extension part 31a having a hole 3b in the center part at the upper end part 31. For example, when the extending portion 31a has a rectangular shape of 7.0 mmSQ in plan view and the extending portion 31a has a circular shape with a diameter of 4.5 mm, the hole 3b has a diameter of 2.0 mm to 4.0 mm in plan view. It is provided in about mm. The hole 3b can take a circular shape, a polygonal shape, or the like, and is formed in a size and a shape that allows external pressure to be transmitted to the flexible portion 4 satisfactorily.

  The flexible portion 4 bends to the inner space 5 side or the opposite side of the inner space 5 according to the external pressure, and functions as a pressure detecting diaphragm. In the example shown in FIG. 1, the flexible portion 4 overlaps the through hole of the frame portion 3 in the upper portion of the internal space 5. When the thickness of the flexible portion 4 is less than 0.01 mm, the mechanical strength is small, and there is a high possibility of breakage when produced using a ceramic green sheet. Moreover, since it will become difficult to bend if the thickness of the flexible part 4 exceeds 1 mm, it will become difficult to function as a diaphragm for pressure detection apparatuses. Therefore, the thickness of the flexible portion 4 is preferably in the range of 0.01 to 1 mm. The pressure detection device using the base for the pressure detection device having the flexible portion 4 having such a thickness functions with high sensitivity under a pressure of, for example, 80 kPa (pressure detection device for low pressure) to 2000 kPa (pressure detection device for high pressure). To do.

  The internal space 5 is preferably a cylindrical shape having a circular shape in plan view. When the internal space 5 has a circular shape in plan view, that is, the through-hole of the frame portion 3 and the flexible portion 4 have a circular shape, when the external pressure is applied, the flexible portion 4 is evenly distributed. Easy to bend. Accordingly, it is possible to reduce a large deformation of a part of the flexible portion 4 having a relatively small thickness, and to detect the external pressure with high sensitivity. In such a case, the electrode 6 preferably has a circular shape as in the shape of the internal space 5 in plan view. By setting it as such an electrode shape, the flexible part 4 can be bent equally.

  The pressure sensor component of the present embodiment includes a base portion 2, a frame portion 3 provided on the base portion 2, a flexible portion 4 provided above the base portion 2 and inside the frame portion 3, and An insulating base 1 having an internal space 5 surrounded by the base portion 2, the frame portion 3, and the flexible portion 4, and a plurality of electrodes 6 provided on the insulating base 1 so as to sandwich the internal space 5. Since the frame portion 3 has an upper end portion 31 positioned above the flexible portion 4 and the upper end portion 31 extends toward the center of the flexible portion 4 in plan view, The possibility of the rubber or resin coating member 11 coming into contact with the flexible portion 4 can be reduced by the upper end portion 31 extending toward the center, and the external pressure can be detected with high accuracy.

(Second Embodiment)
Next, a pressure sensor component according to a second embodiment of the present invention will be described with reference to FIGS.

  In the pressure sensor component in the present embodiment, the difference from the pressure sensor component in the above-described embodiment is that the extension portion 31a approaches the flexible portion 4 toward the central portion of the flexible portion 4 in a cross-sectional view. It is a point inclined like this.

  Further, the concave portion 8 is formed on the lower surface of the base portion 2, the passage 9 connected to the internal space 5 is provided on the upper surface of the insulating base 1, and one of the electrodes 6 is inside the base portion 2. It is a point provided.

  In the pressure sensor component of the present embodiment, when the extending portion 31a is inclined toward the flexible portion 4, for example, when the pressure sensor component is covered with a rubber or resin coating member 11 from above, for example. A large amount of stress applied from the rubber or resin coating member 11 can be applied to the outer peripheral side of the thick upper end portion 31. Therefore, since the stress applied to the extended portion 31a from the rubber or resin coating member 11 is small, it is possible to reduce the occurrence of cracks or the like in the extended portion 31a.

  Such an extension portion 31a is formed so as to be inclined toward the flexible portion 4 when the ceramic green sheets for the plurality of insulating substrates 1 are laminated or when the ceramic green sheet laminate is fired.

  The recess 8 is used, for example, for housing an electronic component. In such a case, the insulating base 1 also functions as a container for protecting the electronic component. At this time, the wiring conductor 7 is also connected to the electronic component, and functions as a wiring for transmitting a change in capacitance to the electronic component or transmitting an electric signal calculated by the electronic component to the external circuit board. . When an electronic component such as an arithmetic processing unit is mounted on a pressure sensor component, the wiring length between the electrode 6 and the electronic component can be shortened as compared with the case where the electronic component is mounted on an external circuit board. Therefore, since the attenuation of the electric signal is small, the external pressure can be detected with high accuracy. In addition, by using a pressure detection device incorporating an electronic component, a pressure sensor module including such a pressure detection device and an external circuit board can be downsized.

  The electronic component is a semiconductor element, a passive element such as a chip capacitor or a chip resistor, an acceleration sensor, or the like as an arithmetic processing device for performing the arithmetic processing described above. The electronic component is sealed by covering the concave portion 8 with a sealing resin such as an epoxy resin or joining a lid made of metal or ceramic to the insulating base 1 so as to close the concave portion 8.

  The passage 9 is used as a passage for discharging the gas generated when the insulating substrate 1 is fired from the internal space 5 to the outside. Since the pressure sensor component has the passage 9, the deformation of the flexible portion 4 can be reduced. The passage 9 is sealed with the sealing material 10 after the insulating substrate 1 is fired, as in the example shown in FIGS. When an Ag brazing material is used as the sealing material 10, a metal layer for bonding is provided in the opening of the passage 9, and sealing is performed by bonding the Ag brazing material to the metal layer.

  In the case where the electrode 6 is embedded in the base portion 2, it is possible to reduce the occurrence of a short circuit between the electrodes 6 due to the flexible portion 4 being greatly bent when a large pressure is applied from the outside. Further, when the electrode 6 provided on the base portion 2 is smaller than the electrode 6 provided on the flexible portion 4, when the pressure sensor component is immersed in the plating solution, the inner space 5 is plated from the passage 9. It can be reduced that the liquid enters and plating is applied to the surface of the electrode 6 to increase the area of the electrode 6.

  The electrode 6 embedded in the base portion 2 can be produced by laminating another ceramic green sheet on the ceramic green sheet on which the metallized paste for the electrode 6 is printed. Alternatively, it is manufactured by printing and applying a ceramic paste substantially the same quality as the ceramic green sheet on the ceramic green sheet on which the metalized paste for the electrode 6 is printed. The ceramic paste is manufactured by adding an organic binder and organic solvent to the main component ceramic powder, and adding a dispersing agent if necessary, and mixing and kneading with a kneading means such as a ball mill, a three-roll mill or a planetary mixer. The Further, when the insulating layer is formed of a ceramic green sheet, the variation in the thickness of the insulating layer on the electrode 6 can be reduced as compared with the case of forming the ceramic paste by printing. It is possible to obtain a pressure sensor component with little variation. The distance from the electrode 6 to the upper surface of the base portion 2 that is in contact with the internal space 5 is preferably 15 μm or more.

(Third embodiment)
Next, a pressure sensor component according to a third embodiment of the present invention will be described with reference to FIG.

  The pressure sensor component according to the present embodiment is different from the pressure sensor component according to the above-described embodiment in that the inner surface of the upper end portion 31 has a curved portion that is curved in a cross-sectional view. is there. That is, the pressure sensor component of the present embodiment has a curved surface shape between the portion extending above the flexible portion 4 and the portion facing the flexible portion 4 on the inner surface of the upper end portion 31. It has the shape of

  The pressure sensor component of the present embodiment has a curved surface portion in which the inner surface of the upper end portion 31 is curved in a sectional view, so that the pressure sensor component is covered with a rubber or resin covering member from above. Since there is no corner between the inner side surface of the frame part 3 and the extension part 31a, the stress concentration can be reduced and the occurrence of cracks or the like in the frame part 3 can be reduced.

(Fourth embodiment)
Next, a pressure sensor component according to a fourth embodiment of the present invention will be described with reference to FIG.

  In the pressure sensor component according to the present embodiment, the difference from the pressure sensor component according to the above-described embodiment is that a plurality of holes 3 b are provided in the extending portion 31 a that extends directly above the flexible portion 4 of the frame portion 3. It is a point. Further, the plurality of holes 3b may be arranged in a lattice pattern or in a staggered pattern.

  In the pressure sensor component of the present embodiment, the plurality of holes 3b are provided in the extending part 31a, so that even if a sudden pressure fluctuation occurs, the outside air is separated from the extending part 31a by the plurality of holes 3b. Since it can pass between the flexible parts 4, an external pressure fluctuation | variation can be detected accurately.

  In addition, this invention is not limited to the example of said embodiment, A various change is possible. For example, the wiring conductor 7 may be provided on the side surface or the lower surface of the insulating substrate 1. In the example shown in FIG. 3, a plurality of wiring conductors 7 are provided from the outer surface of the side wall portion of the recess 8 to the lower surface of the side wall portion. That is, a notch is formed on the side surface of the insulating base 1, and the wiring conductor 7 that functions as a terminal electrode is provided as a so-called castellation conductor on the inner surface of the notch.

DESCRIPTION OF SYMBOLS 1 ... Insulation base 2 ... Base part 3 ... Frame part
31 ... Upper end
31a ... Extension part 4 ... flexible part 5 ... internal space 6 ... electrode 7 ... wiring conductor 8 ... recess 9 ... passage
10 ... Sealing material
11 ... Coating member

Claims (2)

A base part, a frame part provided on the base part, a flexible part provided above the base part and inside the frame part, and surrounded by the base part, the frame part, and the flexible part An insulating substrate having an internal space;
A plurality of electrodes provided on the insulating base so as to sandwich the internal space, and the frame portion has an upper end portion located above the flexible portion,
In plan view, the upper end extends toward the center of the flexible part ,
The pressure sensor component according to the cross-sectional view, wherein the upper end portion is inclined toward the flexible portion toward the central portion of the flexible portion .   2. The pressure sensor component according to claim 1, wherein, in a cross-sectional view, the inner side surface of the upper end portion has a curved surface portion bent in a curved shape.

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