JP2008261750A - Pressure sensor, and diaphragm for pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure sensor securing the airtightness of a sensor element stripe, and a diaphragm for the pressure sensor. <P>SOLUTION: This pressure sensor 10 has two diaphragms 14 stacked in the laminating direction. Space 28 for storing the sensor element stripe 30 is formed between the diaphragms 14. The diaphragms 14 have a pressure receiving section 16 for receiving the pressure to be measured. The sensor element stripe 30 is arranged inside the space 28 and in the pressure receiving section 16 in one diaphragm 14. The sensor element stripe 30 bends following the bending of the pressure receiving section 16. A first recessed part 20 is formed in the outside part of the pressure sensor 10 in the pressure receiving section 16, and a protection material 12 is filled into the first recessed part 20 to cover the pressure receiving section 16. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a diaphragm type pressure sensor and a diaphragm for a pressure sensor.

Some pressure sensors use a diaphragm. In this diaphragm type pressure sensor, since the pressure receiving portion is bent due to a difference in pressure applied to both surfaces of the pressure receiving portion of the diaphragm, the pressure is measured by utilizing the bending of the pressure receiving portion. Patent Document 1 discloses a diaphragm type pressure sensor. The pressure sensor disclosed in Patent Document 1 includes two quartz diaphragms, which are joined together to form a space in which a double tuning fork vibrator is disposed. This double tuning fork vibrator is arranged on the diaphragm on the base side. That is, both ends of the double tuning fork vibrator are joined to the diaphragm on the base side, and the long side direction of the vibrating arm constituting the double tuning fork vibrator is along the plane direction of the diaphragm. When the diaphragm is bent under pressure, the double tuning fork vibrator is also bent. Since the tension or compression stress is applied to the double tuning fork vibrator, the oscillation frequency changes. The pressure sensor measures the pressure and the like from the change in the oscillation frequency.
JP 2004-132913 A

  By the way, a crystal crystal serving as the material of the above-described crystal diaphragm may have a crystal structure defect (linear defect). The quartz diaphragm can be formed by wet etching. However, if a linear defect exists in the quartz crystal, an etch channel is formed in which the portion of the linear defect is selectively etched. As a result, an extremely thin foil portion is formed in the quartz diaphragm partially, or a hole penetrating the upper and lower surfaces of the quartz diaphragm is formed.

  When a foil part exists in the quartz diaphragm, it was discovered when the pressure sensor was completed because the internal space formed by joining two quartz diaphragms in the stacking direction was kept airtight. Difficult to do. In this case, when an impact or the like is applied while using this pressure sensor, a hole is formed in the foil portion, and the airtightness of the internal space is lost. In addition, if there is a through hole in the quartz diaphragm, this through hole is a small hole. For example, even if the pressure sensor is pressurized, the amount of gas entering and leaving the internal space from the through hole is very small. It is difficult to find a through hole.

  As a method for preventing such troubles, as shown in FIG. 5, the entire pressure channel 1 is placed in a concave container 2 and the potting resin 3 is filled in the container 2 so that the entire etch channel is filled. Cover it. However, since this method requires the container 2, it becomes large. When the potting resin 3 is filled in the container 2, the pressure sensor 1 is disposed in the container 2, and then the potting resin 3 is injected from the concave opening. However, in this method, it is difficult for the potting resin 3 to flow between the pressure sensor 1 and the bottom surface (concave bottom surface) of the container 2, and bubbles are generated. If this bubble is present, the bubble expands when the temperature rises. Therefore, the pressure sensor 1 receives the stress when the bubble expands, and cannot accurately measure the pressure. Further, if bubbles are present, the potting resin 3 that should protect the diaphragm has a defect, so that the diaphragm cannot be properly protected. That is, the airtightness of the internal space 4 cannot be ensured. Further, when the potting resin 3 is thermally cured, since the space between the pressure sensor 1 and the bottom surface of the container 2 is in a closed state, the organic solvent cannot be volatilized quickly and becomes uncured or has air bubbles. It will harden while still present.

  An object of this invention is to provide the pressure sensor and the diaphragm for pressure sensors which ensured the airtightness of the sensor element piece.

  A pressure sensor according to the present invention is provided on a pressure receiving portion that receives pressure to be measured, a protective material that covers one surface of the pressure receiving portion, and the other surface of the pressure receiving portion, and as the pressure receiving portion bends. And a sensor element piece that deforms. Since the pressure receiving portion can be reinforced by the protective material, the airtightness of the sensor element piece can be ensured. That is, even when a very thin portion exists in the pressure receiving portion, this portion can be reinforced with a protective material. Further, even when a through hole having a very small diameter exists in the pressure receiving portion, the through hole can be sealed with a protective material. For this reason, even if an impact or the like is applied to the pressure sensor, it is possible to prevent the pressure receiving portion reinforced with the protective material from being perforated and maintain the state where the sensor element piece is hermetically sealed. Therefore, the pressure sensor can continue the pressure measurement even if the pressure receiving portion has a defect.

  In addition, the pressure sensor according to the present invention has a support portion around the pressure receiving portion, and a recess is provided between the one surface of the pressure receiving portion and the support portion so that one surface of the pressure receiving portion is lowered. It is formed, and a protective material is provided in the recess. The protective material can be prevented from flowing out of the pressure receiving portion by the concave portion. Further, by adjusting the height of the recess, the thickness of the protective material covering the pressure receiving portion can be controlled, and the minimum thickness of the protective material covering the pressure receiving portion can be secured.

  The protective material described above is characterized by being in a gel form. Thereby, it becomes difficult for a protective material to inhibit that a pressure receiving part bends, and it can reduce the bad influence to a pressure sensor.

  In the pressure sensor according to the present invention, two diaphragms each having a pressure receiving portion are arranged in the stacking direction, and the sensor element piece is arranged on one diaphragm in a space provided between the diaphragms. It is a feature. Thereby, even if there is a defect in the pressure receiving portion, the airtight state of the space formed between one diaphragm and the other diaphragm can be maintained. Therefore, the pressure sensor can measure the pressure.

  The pressure sensor according to the present invention is characterized in that a diaphragm having a pressure receiving portion and a substrate portion are disposed so as to overlap each other, and a sensor element piece is disposed in a space provided between the diaphragm and the substrate portion. It is said. Thereby, even if there is a defect in the pressure receiving portion, the airtight state of the space formed between the diaphragm and the substrate portion can be maintained. Therefore, the pressure sensor can measure the pressure by the pressure difference between the pressure applied to one surface of the diaphragm and the pressure applied to the other surface.

  The pressure sensor according to the present invention is characterized in that an oscillation circuit is connected to the sensor element piece, and a frequency measurement calculation means is connected to the oscillation circuit. Thereby, the pressure sensor can obtain a pressure value.

  The diaphragm for a pressure sensor according to the present invention is deformed by a pressure difference applied to one surface and the other surface, and has a pressure receiving portion formed of crystal, and has a gel-like shape on the other surface of the pressure receiving portion. It features a protective material. Thereby, a pressure receiving part can be reinforced with a protective material. That is, even when a very thin portion exists in the pressure receiving portion, this portion can be reinforced with a protective material. Further, even when a through hole having a very small diameter exists in the pressure receiving portion, the through hole can be sealed with a protective material.

  Embodiments of a pressure sensor and a pressure sensor diaphragm according to the present invention will be described below. First, the first embodiment will be described. FIG. 1 is a cross-sectional view of a pressure sensor according to the first embodiment. The pressure sensor 10 includes two diaphragms 14 (14a, 14b), a protective member 12 provided on the diaphragm 14, and a sensor element piece 30 provided in an internal space 28 formed by overlapping the two diaphragms 14. have.

  Specifically, each diaphragm 14 receives a pressure to be measured and receives a pressure receiving portion 16 that is bent by a pressure difference applied to one surface 16 a and the other surface 16 b, and a support portion 18 provided around the pressure receiving portion 16. And. The pressure receiving portion 16 is thinner than the support portion 18, and concave portions 20 and 22 are formed on the upper surface and the lower surface of each diaphragm 14, respectively. That is, the diaphragm 14 includes a first recess 20 that forms a step on an outer surface (outer surface) when the diaphragms 14 are joined to each other, and a second recess 22 on a surface (inner surface) where the diaphragms 14 face each other. . And the pressure receiving part 16 is formed of the part used as each bottom face of the 1st recessed part 20 and the 2nd recessed part 22. As shown in FIG. Therefore, a step is provided between the pressure receiving portion 16 and the support portion 18 so that the pressure receiving portion 16 is thinner than the support portion 18.

  Further, one of the two diaphragms 14 (one diaphragm 14a shown in the lower side of FIG. 1) is provided with a fixing portion 24 on the bottom surface of the second recess 22 so that the sensor element piece 30 can be disposed. Yes. That is, one diaphragm 14a includes a fixing portion 24 in the pressure receiving portion 16 facing the other diaphragm 14b (the diaphragm 14 shown in FIG. 1). A pair of the fixing portions 24 is provided so as to support both ends of the sensor element piece 30, and the center portion of the sensor element piece 30 is provided at the center of the pressure receiving portion 16.

  Further, a connecting portion 26 is provided in the second concave portion 22 of one diaphragm 14a. The connecting portion 26 has a shape protruding in the vertical direction from the bottom surface of the second recess 22. When the one diaphragm 14a and the other diaphragm 14b are joined, the connecting portion 26 is joined to the pressure receiving portion 16 (second recess 22) of the other diaphragm 14b. One or more such connecting portions 26 may be provided. When two connecting portions 26 are provided in one diaphragm 14a, for example, each connecting portion 26 is arranged on a straight line passing through the center point of one diaphragm 14a and the sensor joined to one diaphragm 14a. What is necessary is just to arrange | position so that the element piece 30 may be inserted | pinched.

  The one diaphragm 14a and the other diaphragm 14b join the support portions 18 with the second recesses 22 facing each other. As a result, a space 28 for accommodating the sensor element piece 30 is formed inside the diaphragm 14. This space 28 is hermetically sealed.

  In addition, each diaphragm 14 should just be the same shape by planar view, and a planar shape is not specifically limited. For this reason, the planar shape of each diaphragm 14 should just be circular, a rectangle, etc., for example.

  Further, the protective material 12 is provided on the surface of the pressure receiving portion 16 in the outer portion of the pressure sensor 10, that is, on the first concave portion 20 of each diaphragm 14. The protective material 12 covers the pressure receiving portion 16. The protective material 12 is excellent in flexibility, and does not deteriorate the bending function of the pressure receiving portion 16 when the pressure receiving portion 16 receives pressure. For example, the protective material 12 only needs to be in a gel form after being cured, and a more specific example is a silicone gel.

  The sensor element piece 30 is as follows. FIG. 2 is a schematic plan view of the sensor element piece. In FIG. 2, the description of the electrodes provided on the sensor element piece is omitted. The sensor element piece 30 is a double tuning fork vibrating piece 32 as shown in FIG. That is, the sensor element piece 30 has two vibrating arms 34, and a base portion 36 is provided at both ends of these vibrating arms 34. Excitation electrodes (not shown) are provided on the respective vibrating arms 34, and mount electrodes (not shown) connected to the excitation electrodes via connection patterns (not shown) are provided on the base 36. The excitation electrode, the mount electrode, and the connection pattern are provided in a pair so as to have positive and negative polarities. When an electric signal (driving signal) is supplied to the sensor element piece 30, the driving signal is supplied to the excitation electrode via the mount electrode and the connection pattern, and the two vibrating arms 34 are bent toward and away from each other. Vibrate.

  In order to arrange such a sensor element piece 30 on one diaphragm 14a, the base part 36 of the sensor element piece 30 and the fixing part 24 of the one diaphragm 14a may be fixed by a bonding material (not shown). Specifically, a conductive pattern is used as the bonding material to bond the base portion 36 and the fixing portion 24, and the wiring pattern provided on the mount electrode and one diaphragm 14 a via the conductive adhesive (see FIG. (Not shown). As another specific example, the base portion 36 and the fixing portion 24 may be bonded using the bonding material, and a wire may be bonded to the mount electrode and the wiring pattern to be conductive.

  The pressure sensor 10 includes a sensor circuit. FIG. 3 is a block diagram of the sensor circuit. The sensor circuit 40 includes an oscillation circuit 42 and frequency measurement calculation means 44. The oscillation circuit 42 is connected to the sensor element piece 30 on the input side. The oscillation circuit 42 is a circuit that supplies a drive signal to the sensor element piece 30 to oscillate and amplify it. The frequency measurement calculation means 44 is connected to the oscillation circuit 42 on the input side. The frequency measurement calculation means 44 measures the frequency of the signal output from the oscillation circuit 42, that is, the oscillation frequency of the sensor element piece 30, and obtains the pressure from the measurement result.

  Such a pressure sensor 10 can be manufactured as follows. First, when using quartz or the like as the material of the diaphragm 14, the diaphragm 14 is formed by etching. That is, the surface of the quartz base plate is covered with a mask, and the quartz base plate at the opening of the mask is etched to obtain the diaphragm 14. As a result, a step is formed between the one surface 16 a of the pressure receiving portion 16 and the support portion 18 to obtain the first recess 20. Further, a step is formed between the other surface 16 b of the pressure receiving portion 16 and the support portion 18 to obtain the second recess 22. And the depth etc. of the recessed parts 20 and 22 can be correctly controlled by setting etching conditions including etching time etc. suitably. For this reason, the diaphragm 14 is excellent in productivity, and individual differences among the diaphragms 14 hardly occur, so that the characteristics of the pressure sensors 10 become uniform. Note that both the one diaphragm 14a and the other diaphragm 14b can be formed by etching.

  Next, the sensor element piece 30 is disposed on the fixing portion 24 of the one diaphragm 14a. Thereafter, the second concave portions 22 of the diaphragms 14 face each other, and the one diaphragm 14a and the other diaphragm 14b are joined. At this time, since the support portions 18 of the diaphragms 14 are also joined, the sensor element piece 30 is arranged in a space 28 formed between one diaphragm 14a and the other diaphragm 14b.

  The protective material 12 is provided on the outer surface of the pressure sensor 10 in the pressure receiving portion 16. First, the protective material 12 (potting resin) is filled in one of the first recesses 20 provided in one diaphragm 14a and the other diaphragm 14b, respectively, and cured. Thereby, the outer surface of the pressure receiving part 16 is covered with the gel-like protective material 12. Thereafter, the protective material 12 is filled and cured on the side opposite to the first recess 20 filled with the protective material 12 by the above-described process. Thereby, the outer surface of the pressure receiving part 16 is covered with the gel-like protective material 12.

  Since the protective material 12 is injected into the first concave portion 20, the height of the protective material 12 can be adjusted by the height of the first concave portion 20. That is, if the first concave portion 20 is formed by etching as described above, the height of the first concave portion 20 can be accurately controlled. Therefore, if the protective material 12 is injected until all of the first concave portion 20 is filled, There is no individual difference in the thickness of the protective material 12. Therefore, if the thickness of the first recess 20 is set so that the thickness of the protective material 12 necessary for protecting the pressure receiving portion 16 is obtained and the thickness of the protective material 12 can be realized, The desired thickness of the protective material 12 can be reliably obtained by simply filling the protective material 12 so as to fill the entire first recess 20. And the quantity of the protective material 12 with which the 1st recessed part 20 is filled can be adjusted only by changing the height of the 1st recessed part 20. FIG. Further, the first recess 20 prevents the protective material 12 from flowing out of the pressure receiving portion 16.

  Thereafter, the space 28 formed between the joined diaphragms 14 is evacuated using a sealing hole (not shown) provided on the side surface of the diaphragm 14. Then, after the space 28 is set to a predetermined degree of vacuum, the sealing hole is sealed. As a result, the space 28 is hermetically sealed, and the sensor element piece 30 oscillates in a vacuum.

  Next, the operation of the pressure sensor 10 will be described. First, the pressure sensor 10 is arranged in an environment for measuring pressure. Then, the pressure sensor 10 is driven. That is, a drive signal is supplied from the oscillation circuit 42 to the sensor element piece 30, and the signal is amplified and oscillated between them. Then, the oscillation circuit 42 outputs an electric signal (detection signal) having the same frequency as that when the sensor element piece 30 bends and vibrates to the frequency measurement calculation unit 44. The frequency measurement calculation means 44 measures the frequency of the detection signal.

  If the pressure P1 applied to the outside of the pressure sensor 10, that is, the pressure receiving portion 16 of the diaphragm 14, is the same as the pressure P2 of the inside of the pressure sensor 10, that is, the space 28 in which the sensor element piece 30 is accommodated, the pressure receiving portion 16 No change has occurred. At this time, the frequency measurement calculation means 44 measures the frequency f0 of the detection signal. The frequency measurement calculation means 44 compares the reference frequency stored in advance with the frequency f0, and outputs a pressure value corresponding to the frequency f0 registered in advance because there is no new difference between the two frequencies. As a specific example, the frequency f0 of the detection signal when P1 = P2 is registered in advance in the frequency measurement calculation means 44 as the reference frequency, and the difference between the reference frequency f0 and the detected frequency f0 is obtained. Since the difference is zero, the pressure value at the reference frequency f0 registered in one-to-one in advance is output.

  Further, when the pressure P1 outside the pressure sensor 10 becomes larger than the pressure P2 inside the pressure sensor 10, the pressure receiving portion 16 is moved toward the inside of the pressure sensor 10 by the pressure P1 applied to the pressure receiving portion 16 via the protective material 12. Curve (deform). In addition, since the protective material 12 has flexibility, it does not inhibit that the pressure receiving part 16 curves. As the pressure receiving portion 16 is bent, the sensor element piece 30 is also deformed. That is, when the pressure receiving portion 16 is bent, the vibrating arm 34 of the sensor element piece 30 having both ends fixed to the pressure receiving portion 16 is also bent toward the other diaphragm 14b. At this time, the central portion of the vibrating arm 34 is curved inward of the pressure sensor 10 as compared with the base portion 36. When the vibrating arm 34 is curved in this way, a tensile force is applied to the vibrating arm 34, so that the oscillation frequency of the sensor element piece 30 increases. That is, the frequency f1 of the detection signal measured by the frequency measurement calculation means 44 is higher than the frequency f0 when P1 = P2 described above. The frequency measurement calculation means 44 calculates the difference between the reference frequency f0 and the frequency f1, and outputs a pressure value of this difference registered in advance. As a specific example, the relationship between the difference between the reference frequency f0 and the frequency of the detection signal and the pressure value is obtained and registered in advance in the frequency measurement calculation unit 44, and thereafter, the frequency measurement calculation unit 44 What is necessary is just to obtain | require and output the pressure value at the time of this frequency difference using the said relationship registered previously, calculating | requiring the frequency difference of the frequency f1 of the measured detection signal, and the reference frequency f0.

  In addition, when the pressure P1 outside the pressure sensor 10 becomes smaller than the pressure P2 inside the pressure sensor 10, the pressure receiving portion toward the outside of the pressure sensor 10 by the pressure P1 applied to the pressure receiving portion 16 via the protective material 12 16 bends (deforms). In addition, since the protective material 12 has flexibility, it does not inhibit that the pressure receiving part 16 curves. As the pressure receiving portion 16 is bent, the sensor element piece 30 is also deformed. That is, when the pressure receiving portion 16 is bent, the vibrating arm 34 of the sensor element piece 30 having both ends fixed to the pressure receiving portion 16 is also bent in the opposite direction with respect to the other diaphragm 14b. At this time, the central portion of the vibrating arm 34 is curved outward of the pressure sensor 10 as compared with the base portion 36. When the vibrating arm 34 is curved in this manner, a compressive force is applied to the vibrating arm 34, so that the oscillation frequency of the sensor element piece 30 is lowered. That is, the frequency f2 of the detection signal measured by the frequency measurement calculation means 44 is lower than the frequency f0 when P1 = P2 described above. The frequency measurement calculation means 44 obtains a difference between the reference frequency f0 and the frequency f2, and outputs a pressure value of this difference registered in advance. As a specific example, similar to the specific example when P1> P2 described above, the relationship between the difference between the reference frequency f0 and the frequency of the detection signal and the pressure value is obtained in advance in the frequency measurement calculation means 44. After that, the frequency measurement calculation means 44 obtains a frequency difference between the frequency f2 of the measured detection signal and the reference frequency f0, and uses this previously registered relationship to obtain the frequency difference. What is necessary is just to obtain | require and output the pressure value of.

  According to such a pressure sensor 10, since the protective material 12 is provided on the pressure receiving portion 16 facing the outside of the pressure sensor 10, even if the pressure receiving portion 16 has a foil portion due to a linear defect. It can be reinforced with the protective material 12. Thereby, even when an impact or the like is applied when the pressure sensor 10 is used, it is possible to prevent the pressure receiving portion 16 from being perforated, and pressure measurement can be continued. Further, when the diaphragm 14 is formed by etching, even if a small through hole is generated in the pressure receiving portion 16, the through hole can be sealed with the protective material 12. Thereby, since the airtight (vacuum) of the space 28 in which the sensor element piece 30 is arranged can be maintained, the pressure measurement can be continued. Therefore, the pressure sensor 10 can have high reliability.

  Further, since the pressure receiving portion 16 of the diaphragm 14 is made thinner than the support portion 18 to be concave, the protective material 12 can be prevented from flowing out of the pressure receiving portion 16 when the protective material 12 is filled. Moreover, since the height of the recessed parts 20 and 22 can be accurately controlled when forming the diaphragm 14, the quantity of the protective material 12 with which the 1st recessed part 20 is filled can be made appropriate. Therefore, the minimum amount of the protective material 12 necessary for protecting the pressure receiving portion 16 can be secured. Moreover, the protective material 12 can measure a pressure reliably, without inhibiting the bending operation of the pressure receiving part 16 required for a pressure measurement. And the characteristic of the pressure sensor 10 between individuals can be made uniform.

  Further, since the protective material 12 is provided only in the pressure receiving portion 16 that requires it, there is no need to accommodate the entire pressure sensor in a container and cover the periphery with potting resin as shown in FIG. Therefore, since the pressure sensor 10 according to the present embodiment does not require a container that accommodates it, it can prevent the planar direction and the height direction from becoming large.

  Further, since the protective material 12 provided on each of the one diaphragm 14a and the other diaphragm 14b can be inspected from the outside, even if bubbles or the like are generated when the protective material 12 is filled in the first recess 20, the bubbles or the like are easily formed. Can be found. For this reason, since the defective pressure sensor 10 can be removed, the shipped pressure sensor 10 can accurately measure the pressure. In this case, it is desirable that the protective material 12 is transparent in order to improve the visibility at the time of inspection.

  Next, a second embodiment will be described. In the second embodiment, the same reference numerals are given to the same parts as those described in the first embodiment, and the description thereof is omitted. FIG. 4 is a cross-sectional view of a pressure sensor according to the second embodiment. The pressure sensor 50 according to the second embodiment has a configuration in which the other diaphragm 14b described in the first embodiment is replaced with a substrate portion 52. That is, the sensor element piece 30 is provided in the space 28 formed by stacking the pressure sensor 50, one diaphragm 14 and the substrate portion 52 in the stacking direction.

  More specifically, the substrate portion 52 is provided with a third recess 54 on the surface facing the diaphragm 14 to form a space 28 for accommodating the sensor element piece 30 when joined to the diaphragm 14. Yes. Various materials including quartz can be used as the material of the substrate portion 52. The diaphragm 14 may be the same as the one diaphragm 14a described in the first embodiment. That is, the diaphragm 14 used in the second embodiment only needs to include the support portion 18, the pressure receiving portion 16, the concave portions 20 and 22, and the fixing portion 24. Each of these parts has the same configuration as that described in the first embodiment. A protective material 12 is provided in the first recess 20 of the diaphragm 14.

And the sensor element piece 30 is arrange | positioned in the diaphragm 14 by joining the base part 36 and the adhering part 24 of the diaphragm 14 which were provided in the both ends. The space 28 between the diaphragm 14 in which the sensor element piece 30 is accommodated and the substrate portion 52 is hermetically sealed. If the space 28 is in an absolute vacuum, the pressure sensor 10 can measure the absolute pressure.
Even with such a pressure sensor 50, it is possible to obtain the same operation and effect as the pressure sensor 50 described in the first embodiment.

  In the first and second embodiments described above, the first recess 20 is provided in the pressure receiving portion 16 and the protective material 12 is provided there. However, the first recess 20 may not be provided. That is, the support portion 18 constituting the diaphragm 14 and the outer surface (one surface 16a) of the pressure receiving portion 16 may be in the same plane. Even in this case, the protective material 12 may be provided on the outer surface of the pressure sensor 10 in the pressure receiving portion 16.

  In the first and second embodiments, a double tuning fork vibrating piece 32 is used as the sensor element piece 30. However, the sensor element piece 30 of the present invention is not limited to the double tuning fork vibrating piece 32 but may be a surface acoustic wave resonance piece or the like. Further, the sensor element piece 30 may be a vibration element (MEMS) manufactured by finely processing silicon or a vibration element in which a piezoelectric material is provided on a metal body. In addition, if the piezoelectric element is used as the sensor element piece 30, especially a crystal is used, various characteristics such as frequency temperature characteristics are better than those using other materials. Accuracy can be measured.

It is sectional drawing of the pressure sensor which concerns on 1st Embodiment. It is a schematic plan view of a sensor element piece. It is a block diagram of a sensor circuit. It is sectional drawing of the pressure sensor which concerns on 2nd Embodiment. It is sectional drawing of the structure which has arrange | positioned the pressure sensor in the container and was covered with potting resin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,50 ......... Pressure sensor, 12 ......... Protective material, 14 ......... Diaphragm, 14a ......... One diaphragm, 16 ......... Pressure receiving part, 18 ... Supporting part, 20 ......... First recessed part, 28... Space 30... Sensor element piece 42... Oscillator circuit 44.

Claims (7)

A pressure-receiving unit that receives pressure to be measured;
A protective material covering one surface of the pressure receiving portion;
A sensor element piece disposed on the other surface of the pressure receiving portion and deformed as the pressure receiving portion bends;
A pressure sensor comprising: A support portion around the pressure receiving portion;
Between the one surface of the pressure receiving portion and the support portion, a step is provided where the one surface of the pressure receiving portion is lowered to form a recess,
The pressure sensor according to claim 1, wherein the protective material is provided in the recess.   The pressure sensor according to claim 1, wherein the protective material is in a gel form.   2. The diaphragm having the pressure receiving portion is disposed so as to be overlapped in the stacking direction, and the sensor element piece is disposed on one diaphragm in a space provided between the diaphragms. The pressure sensor in any one of thru | or 3. Disposing the diaphragm provided with the pressure receiving portion and the substrate portion,
The sensor element piece is disposed in a space provided between the diaphragm and the substrate portion.
The pressure sensor according to any one of claims 1 to 3, wherein   6. The pressure sensor according to claim 1, wherein an oscillation circuit is connected to the sensor element piece, and a frequency measurement calculation means is connected to the oscillation circuit. It has a pressure receiving portion that is deformed by a pressure difference applied to one surface and the other surface, and is formed of quartz.
A gel-like protective material is provided on the other surface of the pressure receiving portion.
Diaphragm for pressure sensor.

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