JP2012026901A - Pressure sensor and vacuum apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor capable of measuring pressure by improving resolution in a wide pressure range while maintaining miniaturization, and to provide a vacuum apparatus using the pressure sensor.SOLUTION: Each of pressure sensors 10A to 10E includes: base frame bodies 20A, 20B for regulating at least a first virtual surface 21 and a second virtual surface 22 on an outside surface of the frame; a first diaphragm 50 arranged on a face covering the first virtual surface; a second diaphragm 60 arranged on a face covering the second virtual surface; airtight spaces 70, 90 formed so as to be sectioned at least by the base frame bodies, and the first and second diaphragms and having inner pressure lower than a measurement pressure range P; and first detection elements 30, 40 arranged in the airtight spaces to detect the displacement of the first and second diaphragms. The first diaphragm is displaced in response to the pressure of at least a first pressure range P1 of the high pressure side out of the measurement pressure range P, and the second diaphragm is displaced in response to the pressure of at least a second pressure range P2 including the lower pressure side than the first pressure range P1 by resolution higher than that of the first diaphragm.

Description

  The present invention relates to a pressure sensor and a vacuum device using the same.

  A pressure sensor using a quartz resonator, for example, a double tuning fork type quartz resonator, as a detection element is known. In Patent Document 1, an internal space that is divided by a diaphragm and a lid and is set to a negative pressure is formed, and a crystal resonator connected to the diaphragm is disposed in the internal space. Thereby, a differential pressure between the pressure P1 acting on the diaphragm and the pressure P2 in the internal space is detected.

  A pressure sensor having a quartz diaphragm on two opposing surfaces is disclosed in Patent Document 2. In this pressure sensor, crystal diaphragms on two opposing surfaces are connected by a force transmission column. Then, the two crystal diaphragms are displaced by the differential pressure between the pressure P1 (negative pressure) acting on one crystal diaphragm and the pressure P2 (atmospheric pressure) acting on the other crystal diaphragm, and the displacement is applied to the crystal resonator. The differential pressure of pressure P1 with respect to pressure P2 is transmitted and measured along with its polarity.

JP 2004-132913 A JP 2004-132913 A

  In the technique of Patent Document 1, the pressure-strain amount characteristic is determined by the characteristic of one diaphragm. Since the two diaphragms of Patent Document 2 are also displaced together, the pressure-strain amount characteristic is a single characteristic. The pressure-strain characteristic of the diaphragm is uniquely determined by, for example, the thickness of the diaphragm.

  Conventionally, for example, in order to measure a wide pressure range from atmospheric pressure to high vacuum, a plurality of pressure sensors having different diaphragm characteristics must be installed. As a result, the area of the sensor unit occupied by the vacuum apparatus is increased in size and cost. If each pressure sensor is the pressure sensor disclosed in Patent Document 1, the pressure in the internal space must be made uniform among the individual pressure sensors, and if it is not uniform, correction is required. Also, if the number of pressure sensors was reduced to reduce the price, it was impossible to measure the pressure with high accuracy over the entire pressure range.

  Accordingly, some aspects of the present invention have an object to provide a pressure sensor that can measure with a high resolution in a wide pressure range while maintaining a small size, and a vacuum apparatus using the pressure sensor.

The pressure sensor according to one aspect of the present invention is:
A base frame body defining at least a first virtual surface and a second virtual surface on the outer surface of the frame;
A first diaphragm disposed on a surface covering the first virtual surface;
A second diaphragm disposed on a surface covering the second virtual surface;
An airtight space formed by at least the base frame and the first and second diaphragms and having an internal pressure lower than a measurement pressure range;
A first detection element disposed in the airtight space;
A second detection element disposed in the airtight space;
Have
The first diaphragm is displaced in response to the pressure in at least the first pressure range on the high pressure side of the measurement pressure range, and the displacement of the first diaphragm is detected by the first detection element,
The second diaphragm is displaced in response to at least a second pressure range including a lower pressure side than the first pressure range in the measurement pressure range with a resolution higher than that of the first diaphragm, The displacement of the second diaphragm is detected by the second detection element.

  In one embodiment of the present invention, the pressure in the pressure range of interest including the first pressure range on the high pressure side and the second pressure range on the low pressure side can be detected with one pressure sensor, and the detectable pressure range. Expands. At this time, in each of the first and second diaphragms, an internal pressure of the airtight space acts on one surface, and an external pressure higher than the internal pressure acts on the other surface, and the internal and external differential pressure causes the internal pressure toward the inside of the airtight space. Will be displaced. Therefore, when this pressure sensor is disposed in the measurement atmosphere, the internal pressure acting on each of the first and second diaphragms is equal, and the external pressure acting on each of the first and second diaphragms is also equal. Therefore, in the two measurement systems measured by each of the first and second diaphragms, adjustment depending on the pressure difference between the two systems is unnecessary. Moreover, if it is attempted to detect pressures in a wide range of measurement pressures using only the first diaphragm and the first detection element, the amount of displacement of the first diaphragm decreases as the pressure decreases, and the resolution decreases. In one aspect of the present invention, the pressure in the second pressure range on the low pressure side can be detected with a higher resolution than the first diaphragm by the second diaphragm, so that the pressure can be detected with a relatively high resolution over a wide range. . Further, when the pressure (internal pressure) in the airtight space is low as described above, it becomes possible to ignore the influence of the change in the internal pressure accompanying the deformation of the first and second diaphragms.

  In one aspect of the present invention, the first pressure range may include standard atmospheric pressure, and the upper limit of the second pressure range may be a negative pressure.

  In other words, this pressure sensor can be used for measurement of standard atmospheric pressure and negative pressure lower than that, and can be suitably used for pressure measurement in a vacuum apparatus in which air-vacuum replacement is performed, for example. In particular, it is suitable for measuring a wide range of pressure from low vacuum to high vacuum.

  In one aspect of the present invention, the airtight space can be set to a pressure that is two orders of magnitude lower than the lower limit pressure of the measurement pressure range.

  In this way, whenever a pressure within the measurement pressure range acts as an external pressure, a sufficient pressure difference between the internal pressure and the external pressure in the airtight space is always generated, and the internal pressure can always be lower than the external pressure. The pressure can be measured by displacing the first and second diaphragms toward the airtight space.

  In one aspect of the present invention, it may further include a first stopper portion that regulates displacement of the second diaphragm when a pressure higher than the upper limit of the second pressure range is applied.

  The second diaphragm, which responds and displaces with higher resolution than the first diaphragm under the same pressure, displaces the second diaphragm at the first stopper even if the displacement amount on the upper limit side of the first pressure range increases. Can be regulated. Therefore, the upper limit of the second pressure range can be mechanically set by the first stopper portion, and the second diaphragm can be accurately operated within the second pressure range. Moreover, even if an excessively high pressure acts on the second diaphragm, the second diaphragm can be prevented from being damaged.

In one aspect of the present invention, the base frame further defines a third virtual surface on the outer surface of the frame, and the pressure sensor is disposed on a surface covering the third virtual surface;
A third detection element disposed in the hermetic space, wherein the third diaphragm has a pressure within at least a third pressure range including a lower pressure side than the second pressure range in the measurement pressure range. The displacement is responsive in higher resolution than the second diaphragm, and the displacement of the third diaphragm can be detected by the third detection element.

  In this way, when measuring the pressure within the same measurement pressure range, the resolution measured by the three diaphragms can be increased rather than the resolution measured by the two diaphragms, so that the measurement accuracy can be further improved. it can. Alternatively, the pressure range measured by the three diaphragms can be expanded more than the pressure range measured by the two diaphragms, and the dynamic range can be expanded.

  In one aspect of the present invention, when a pressure higher than the upper limit of the second pressure range is applied, the first stopper portion that restricts the displacement of the second diaphragm, and the pressure higher than the upper limit of the third pressure range are applied. And a second stopper portion for restricting displacement of the third diaphragm when acted on.

  In this way, the second and third diaphragms that respond and displace with higher resolution than the first and second diaphragms under the same pressure, even if the displacement amount on the upper limit side of the second and third pressure ranges increases. The displacement of the second and third diaphragms can be restricted by the first and second stopper portions. Therefore, the upper limits of the second and third pressure ranges can be mechanically set by the first and second stopper portions, and the second and third diaphragms can be operated accurately within the second and third pressure ranges, respectively. Can do. Moreover, even if an excessively high pressure acts on the second and third diaphragms, the second and third diaphragms can be prevented from being damaged.

  In one aspect of the present invention, the base frame further defines a fourth virtual surface on the outer surface of the frame, and the pressure sensor includes a fourth diaphragm disposed on a surface covering the fourth virtual surface, A fourth detection element disposed in an airtight space, wherein the fourth diaphragm has a pressure in at least a fourth pressure range including a lower pressure side than the third pressure range in the measurement pressure range. The displacement is responsive in higher resolution than the third diaphragm, and the displacement of the fourth diaphragm can be detected by the fourth detection element.

  In this way, when measuring pressures within the same measurement pressure range, the resolution measured by the four diaphragms can be higher than the resolution measured by the two or three diaphragms, thus further improving the measurement accuracy. Can be made. Alternatively, the pressure range measured by the four diaphragms can be expanded rather than the pressure range measured by the two or three diaphragms, and the dynamic range can be further expanded.

  In other words, in one aspect of the present invention, the base frame further defines the k-th virtual plane (k is one or more integers satisfying 3 ≦ k ≦ N, and N is an integer satisfying 3 ≦ N). The pressure sensor further includes a kth diaphragm disposed on a surface covering the kth virtual surface, and a kth detection element disposed in the sealed space, wherein the kth diaphragm is k-1) Higher resolution than the (k-1) diaphragm in the pressure of the kth pressure range having an upper limit in the pressure range and having a lower limit on the lower pressure side than the (k-1) pressure range. The displacement of the kth diaphragm can be detected by the kth detection element.

  In one aspect of the present invention, when a pressure higher than the upper limit of the second pressure range is applied, the first stopper portion that restricts the displacement of the second diaphragm, and the pressure higher than the upper limit of the third pressure range are applied. A second stopper portion that regulates displacement of the third diaphragm when acted, a third stopper portion that regulates displacement of the fourth diaphragm when a pressure higher than the upper limit of the fourth pressure range acts, Can further be included.

  Thus, the upper limits of the second to fourth pressure ranges can be mechanically set by the first to third stopper portions, and the second to fourth diaphragms can be operated accurately within the second to fourth pressure ranges, respectively. Can do. Moreover, even if an excessively high pressure acts on the second to fourth diaphragms, the second to fourth diaphragms can be prevented from being damaged.

  In one aspect of the present invention, the base frame body defines at least one (M + 1) virtual surface in addition to the first to Mth virtual surfaces (M is an integer from 2 to 4), The airtight space can be formed by covering at least one (M + 1) virtual surface with a lid.

  In other words, when two to four diaphragms are attached to the virtual surface of the base frame, it is possible to share the base frame regardless of the number of diaphragms installed by providing at least one extra virtual surface. it can. An airtight space can be secured by attaching a lid to at least one extra virtual surface.

  In one aspect of the present invention, the base frame includes a first frame outer surface and a second frame outer surface, and the pressure sensor is bonded to the first frame outer surface of the base frame, and the first detection element A first support frame that supports the second detection frame, a second support frame that is bonded to the outer surface of the second frame of the base frame, supports the second detection element, and is bonded to the first support frame, A first lid having a first diaphragm and a second lid having the second diaphragm joined to the second support frame may be further included.

  Thus, by laminating the first and second support frames and the first and second lids on the outer surfaces of the first and second frames of the base frame, respectively, the first and second diaphragms and the first and second diaphragms are laminated. A pressure sensor including the second detection element can be easily manufactured.

  In one aspect of the present invention, the displacement of the second diaphragm is restricted when a pressure higher than the upper limit of the second pressure range is applied between the second support frame and the second lid. A first stopper support frame for supporting the first stopper portion to be further provided.

  Thus, the 1st stopper part which controls the displacement of the 2nd diaphragm can be arranged easily by interposing the 1st stopper support frame between the 2nd support frame and the 2nd lid. .

  In one aspect of the present invention, the base frame further includes a third frame outer surface, and the pressure sensor is bonded to the third frame outer surface of the base frame and supports a third detection element. A frame and a third lid joined to the third support frame and having a third diaphragm, the third diaphragm being more than the second pressure range of the measurement pressure range The displacement of the third diaphragm can be detected by the third detection element in response to displacement at a resolution higher than that of the second diaphragm to a pressure in at least the third pressure range including the low pressure side.

  In this way, a pressure sensor further including a third diaphragm and a third detection element is easily manufactured by laminating the third support frame and the third lid on the outer surface of the third frame of the base frame. be able to.

  In one aspect of the present invention, the displacement of the third diaphragm is restricted when a pressure higher than the upper limit of the third pressure range is applied between the third support frame and the third lid. A second stopper support frame for supporting the second stopper portion to be further provided.

  Thus, the 2nd stopper support frame which controls the displacement of the 3rd diaphragm can be easily arranged by interposing the 2nd stopper support frame between the 3rd support frame and the 3rd lid. .

  In one aspect of the present invention, the base frame further includes a fourth frame outer surface, and the pressure sensor is bonded to the fourth frame outer surface of the base frame and supports a fourth detection element. A frame and a fourth lid joined to the fourth support frame and having a fourth diaphragm, wherein the fourth diaphragm is more than the third pressure range in the measurement pressure range. Displacement is made in response to at least the pressure in the fourth pressure range including the low pressure side with a resolution higher than that of the third diaphragm, and the displacement of the fourth diaphragm can be detected by the fourth detection element.

  Thus, the pressure sensor further including the fourth diaphragm and the fourth detection element is easily manufactured by laminating the fourth support frame and the fourth lid on the outer surface of the fourth frame of the base frame. be able to.

  In one aspect of the present invention, the displacement of the fourth diaphragm is regulated when a pressure higher than the upper limit of the fourth pressure range is applied between the fourth support frame and the fourth lid. And a third stopper support frame that supports the third stopper portion.

  Thus, by interposing the third stopper support frame body between the fourth support frame body and the fourth lid body, the third stopper portion for restricting the displacement of the fourth diaphragm can be easily arranged. .

  In one aspect of the present invention, each of the first and second detection elements is formed by a piezoelectric vibrator, and the first lid transmits a displacement of the first diaphragm to the first detection element. A second transmission unit configured to transmit a displacement of the second diaphragm to the second detection element; and the first stopper unit is opposed to the second diaphragm. A stopper surface formed on the surface, and a relief portion formed on a surface facing the second detection element and allowing vibration of the second detection element.

  Thus, when each of the first and second detection elements is formed by a piezoelectric vibrator, the displacement of the first diaphragm is transmitted to the first detection element via the first transmission section, and the second diaphragm is The displacement is transmitted via the second transmission unit. Since the first stopper portion having the first stopper surface that regulates the displacement of the second diaphragm has the escape portion, the vibration of the second detection element that is a piezoelectric vibrator is not hindered.

  Another aspect of the present invention defines a vacuum device having the above-described pressure sensor positioned facing the area to be atmosphere-vacuum displaced.

1 is a schematic exploded perspective view of a pressure sensor according to a first embodiment of the present invention. It is sectional drawing of the pressure sensor shown in FIG. It is a characteristic view which shows an example of the characteristic of the pressure-strain amount of the 1st, 2nd diaphragm used for 1st Embodiment of this invention. It is a disassembled perspective view of the pressure sensor which further has a 1st stopper part. It is sectional drawing of the pressure sensor shown in FIG. It is a disassembled perspective view of the pressure sensor which concerns on 2nd Embodiment (N = 4) of this invention. FIG. 7 is a first sectional view of the pressure sensor shown in FIG. 6. FIG. 7 is a second sectional view of the pressure sensor shown in FIG. 6. It is a characteristic view which shows an example of the characteristic of the pressure-strain amount of the 1st-4th diaphragm used for 2nd Embodiment (N = 4) of this invention. It is a disassembled perspective view of the pressure sensor which concerns on 2nd Embodiment (N = 3) of this invention. It is sectional drawing of the pressure sensor shown in FIG. It is a characteristic view which shows an example of the characteristic of the pressure-strain amount of the 1st-3rd diaphragm used for 2nd Embodiment (N = 3) of this invention. It is a disassembled perspective view of the pressure sensor which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the 1st cross section of the pressure sensor shown in FIG. It is sectional drawing which shows the 2nd cross section of the pressure sensor shown in FIG. It is a schematic perspective view which shows the pressure sensor attached to a part of vacuum apparatus.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not necessarily.

1. 1. First embodiment 1.1. Basic Structure FIG. 1 is a schematic exploded perspective view of a pressure sensor according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of the pressure sensor shown in FIG. 1, and FIG. 3 is a diagram of first and second diaphragms. It is a characteristic view which shows an example of the characteristic of a pressure-strain amount. In FIG. 1, the pressure sensor 10A has a base frame 20A. The base frame 20A has, for example, a square frame shape. One of the two opposing frame outer surfaces defined by the square frame-shaped base frame 20 </ b> A is referred to as a first virtual surface 21, and the other is referred to as a second virtual surface 22. The first virtual surface 21 is the same plane as the first frame outer surface 21A of the base frame body 20A, and includes a plane that faces the space 70A surrounded by the base frame body 20A. Similarly, the second virtual surface 22 is the same plane as the second frame outer surface 22A facing the first frame outer surface 21A of the base frame 20A, and includes a surface facing the space 70A.

  The pressure sensor 10 </ b> A further includes a first diaphragm 50 disposed on a surface covering the first virtual surface 21 and a second diaphragm 60 disposed on a surface covering the second virtual surface 22. An airtight space 70 is formed by the base frame body 20A and the first and second diaphragms 50 and 60 (see FIG. 2). In the airtight space 70, the first detection element 30 and the second detection element 40 are arranged.

  The pressure sensor 10 </ b> A shown in FIG. 1 detects the displacement of the first diaphragm 50 caused by the pressure acting on the first diaphragm 50 by the first detection element 30, and causes the first pressure caused by the pressure acting on the second diaphragm 60. The displacement of the two diaphragms 60 is detected by the second detection element 40.

Here, the measurement pressure range P of interest detected by the pressure sensor 10A is shown in FIG. In FIG. 3, the measurement pressure range P is, for example, a pressure that changes in a vacuum apparatus that is subjected to air-vacuum substitution, the upper limit is, for example, 10 ⁵ Pa that is close to the standard atmospheric pressure, and the lower limit is, for example, a high vacuum. ^-3 Pa. The measurement pressure range P includes a first pressure range P1 on the high pressure side and a second pressure range P2 on the low pressure side. In FIG. 3, the first and second pressure ranges P1 and P2 include regions that overlap each other. That is, the lower limit P1L of the first pressure range P1 belongs to the second pressure range P2, and the upper limit P2U of the second pressure range P2 belongs to the first pressure range P1. The upper limit P1U of the first pressure range P1 is, for example, 10 ⁵ Pa that matches the upper limit PU of the measurement pressure range P, and the lower limit P2L of the second pressure range P2 is, for example, 10 ⁻³ Pa that matches the lower limit PL of the measurement pressure range P. It is.

  The first diaphragm 50 is displaced according to the characteristic C11 shown in FIG. 3 in response to at least the pressure in the first pressure range P1 shown in FIG. 3, and the displacement of the first diaphragm 50 is detected by the first detection element 30. . Of course, the first diaphragm 50 is displaced by pressures other than the first pressure range P1 (see the broken line in FIG. 3), but the first pressure range P1 is an object of measurement.

  The second diaphragm 60 is displaced according to the characteristic C12 shown in FIG. 3 in response to at least the pressure in the second pressure range P2 shown in FIG. 3, and the displacement of the second diaphragm 60 is detected by the second detection element 40. . Of course, the second diaphragm 60 is displaced by a pressure other than the second pressure range P2 (see the broken line in FIG. 3), but the second pressure range P2 is an object of measurement.

  Here, in each of the first and second diaphragms 50, 60, the internal pressure of the airtight space 70 acts on one surface, the external pressure acts on the other surface, and is displaced by the internal / external differential pressure. Therefore, when this pressure sensor 10A is arranged in the measurement atmosphere, the internal pressures acting on each of the first and second diaphragms 50, 60 are equal, and the external pressures acting on each of the first, second diaphragms 50, 60 are also equal. . Therefore, in the two measurement systems measured by the first and second diaphragms 50 and 60, adjustment depending on the pressure difference between the two systems becomes unnecessary.

  As shown in FIG. 3, the first and second diaphragms 50 and 60 differ in the amount of deflection when the same pressure (for example, a pressure in the range of 1.0 to 10 Pa in FIG. 3) is applied. Therefore, in this embodiment, for example, the thickness t2 (see FIG. 3) of the second diaphragm 60 is thinner than the thickness t1 (see FIG. 3) of the first diaphragm 50 (t2 <t1). Thereby, when the same pressure is applied to the first and second diaphragms 50 and 60, the amount of bending of the second diaphragm 60 is larger than the amount of bending of the first diaphragm 50. This is because the amount of deflection is inversely proportional to the cube of the diaphragm thickness, as is apparent from the well-known deflection formula of, for example, both-end fixed beams. In order to change the deflection amount of the first and second diaphragms 50 and 60, other parameters such as the size of the diaphragm may be changed instead of the thickness or together with the thickness.

  A characteristic C11 in FIG. 3 is a pressure-strain amount characteristic when the thickness t1 of the first diaphragm 50 is, for example, 200 μm, and a characteristic C12 in FIG. 3 is a thickness t2 of the second diaphragm 60, for example, 20 μm. It is a pressure-strain amount characteristic. The effective diameter of the first and second diaphragms 50 and 60 is 10 mm. FIG. 3 is a logarithmic graph showing both axes of pressure (horizontal axis) and deflection (vertical axis) in logarithm. In FIG. 3, the characteristics C11 and C12 are represented by straight lines, for example.

  Here, if it is attempted to detect the pressure in the wide measurement pressure range P using only the first diaphragm 50 and the first detection element 30, the displacement amount of the first diaphragm 50 becomes smaller toward the lower pressure side as shown in FIG. Will fall. That is, the smaller the change in the amount of deflection with respect to the pressure change, the lower the resolution. In the present embodiment, the pressure in the second pressure range P <b> 2 on the low pressure side is detected by the second diaphragm 60 that is thinner than the first diaphragm 50, for example.

  The second diaphragm 60 has, for example, two or more orders of magnitude greater deflection than the first diaphragm 50 when the same pressure (for example, a pressure in the range of 1.0 to 10 Pa in FIG. 3) is applied. That is, since the pressure on the low pressure side can be detected by the second diaphragm 60 with a higher resolution than the first diaphragm 50, the pressure can be detected with a relatively high resolution over a wide range.

In addition, since the measurement pressure range of the second diaphragm 60 is the second pressure range P2 on the low pressure side, for example, the first stopper portion 80 (FIG. 4 to be described later) prevents the second diaphragm 60 from being bent at a pressure close to atmospheric pressure. And FIG. 5). In this way, the upper limit P2U of the second pressure range P2 that is the pressure range of interest in the second diaphragm 60 can be mechanically set. The first diaphragm 50 may be similarly provided with a stopper portion. However, if the measurement atmosphere does not become excessively higher than the atmospheric pressure, it is not always necessary to provide the stopper portion on the first diaphragm 50. At this time, the first diaphragm 50 has a strain amount of about 0.2 mm (200 μm) at 10 ⁺⁵ Pa (approximately standard atmospheric pressure). Since the diaphragm does not have hysteresis and does not break up to a strain amount similar to the thickness, the first diaphragm 50 can have resistance even at atmospheric pressure. Further, the first stopper portion (FIGS. 4 and 5) for mechanically setting the upper limit P2U of the second pressure range P2 is not necessarily required, and the second diaphragm 60 is resistant even in the first pressure range P1. This is unnecessary.

1.2. Specific Structure As shown in FIG. 1, the rectangular frame-shaped base frame body 20 </ b> A includes a first frame outer surface 21 </ b> A located on the first virtual surface 21 and a second frame outer surface 22 </ b> A located on the second virtual surface 22. Including.

  The pressure sensor 10 </ b> A further includes a first support frame 32 that is bonded to the first frame outer surface 21 </ b> A of the base frame 20 </ b> A and supports the first detection element 30. The pressure sensor 10 </ b> A further includes a second support frame 42 that is bonded to the second frame outer surface 22 </ b> A of the base frame 20 </ b> A and supports the second detection element 40. The first and second support frame bodies 32 and 42 including the first and second detection elements 30 and 40 can be used in common, and parts can be shared.

  The pressure sensor 10A includes a first lid 52 that is joined to the first support frame 32 and includes a first diaphragm 50 that is displaced in response to at least the first pressure range P1 shown in FIG. Similarly, the pressure sensor 10 </ b> A is joined to the second support frame body 42, and includes a second diaphragm 60 that is displaced in response to at least a second pressure range P <b> 2 with higher resolution than the first diaphragm 50. A lid 62 is provided. The first and second diaphragms 50 and 60 are not limited to those formed on the entire bottom surface of the first and second lids 52 and 62, and for example, a part of the central circular region or the like may be formed thin. .

  The base frame body 20A, the first and second support frames 32 and 42, and the first and second lid bodies 52 and 62 each have spaces 70A to 70E surrounded by them. By joining the base frame body 20A, the first and second support frames 32 and 42, and the first and second lid bodies 52 and 62, the spaces 70A to 70E are made the airtight space 70. The base frame 20A, the first and second support frames 32 and 42, and the first and second lids 52 and 62 can be bonded to each other with an adhesive to form an airtight structure. The pressure sensor 10A can be assembled in a vacuum, or the airtight space 70 can be evacuated by evacuating the airtight space 70 after the pressure sensor 10A is assembled. The evacuation after the assembly of the pressure sensor 10 </ b> A can be performed through a gas adsorption action by a getter material accommodated in the airtight space 70 or a hole communicating with the airtight space. The communication hole is sealed after evacuation.

Here, the airtight space 70 can be set to a pressure that is two orders of magnitude lower than the lower limit pressure PL of the measurement pressure range P. In this embodiment, since the lower limit pressure PL of the measurement pressure range P is 10 ⁻³ Pa, the pressure in the airtight space 70 can be set to a pressure lower than 10 ⁻⁵ Pa.

  In this way, whenever the pressure in the measurement pressure range P acts as an external pressure, a sufficient pressure difference between the internal pressure and the external pressure in the airtight space 70 is always generated, and the internal pressure can always be lower than the external pressure. The first and second diaphragms 50 and 60 can be displaced inward to measure pressure.

  The pressure sensor 10 </ b> A shown in FIG. 1 detects the displacement of the first diaphragm 50 caused by the pressure acting on the first diaphragm 50 by the first detection element 30, and causes the first pressure caused by the pressure acting on the second diaphragm 60. The displacement of the two diaphragms 60 is detected by the second detection element 40.

  Here, in the present embodiment, the first and second detection elements 30 and 40 can each be formed of a vibrator, particularly a piezoelectric vibrator such as a quartz vibrator, more preferably a double tuning fork type quartz vibrator. As is well known, the resonance frequency of the vibrators 30 and 40 changes when stress is generated in the axial direction. Therefore, if this frequency change is measured, a pressure value that causes stress generation according to the frequency change can be obtained. it can. When the first and second detection elements 30 and 40 are respectively formed by vibrators, the second detection element 30 is more second than the first detection element 30 in the same manner as the thickness relationship of the first and second diaphragms 50 and 60. The detection element 40 may be formed thin. This is because the displacement of the thin second diaphragm 60 can be easily transmitted to the second detection element 40.

  When each of the first and second detection elements 30 and 40 is formed by a vibrator, for example, two first transmission portions 54 protrude from the first diaphragm 50 in the first lid 52 as shown in FIG. Provided. Similarly, a second transmission portion 64 is provided on the second lid 62 so as to protrude from the second diaphragm 60. The first transmission unit 54 transmits the displacement of the first diaphragm 50 to the first detection element 30, and the second transmission unit 64 transmits the displacement of the second diaphragm 62 to the second detection element 40.

  In this manner, the pressure sensor 10A is formed by the base frame body 20A, the first and second support frame bodies 32 and 42, and the first and second lid bodies 52 and 62, so that the first in the airtight space 70 is obtained. The second detection elements 30 and 40 can be easily arranged.

1.3. First Stopper Part FIG. 4 is an exploded perspective view of a pressure sensor 10B further having a first stopper part 80, and FIG. 5 is a cross-sectional view of the pressure sensor 10B shown in FIG. 4 and 5, the base frame body 20A, the first and second support frame bodies 32 and 42, and the first and second lid bodies 52 and 62 having the same function as the members shown in FIGS. Are denoted by the same reference numerals as those in FIGS. 1 and 2, and detailed description thereof will be omitted.

  The first stopper 80 mechanically sets an upper limit P2U of the second pressure range P2, which is the pressure range of interest in the second diaphragm 60. The first stopper portion 80 can be provided, for example, on the first stopper support frame body 82 disposed between the second support frame body 42 and the second lid body 62.

  The first stopper portion 80 has a first stopper surface 84 on the surface facing the second diaphragm 60. The gap g1 between the first stopper surface 84 and the second diaphragm 60 becomes zero when a pressure higher than the upper limit P2U of the second pressure range P2 shown in FIG. 3 is applied, thereby restricting the displacement of the second diaphragm. Is done. In addition, when the 1st stopper support frame 82 is expanded, the protrusion height of 2nd transmission part 64A provided in the 2nd cover body 62 is higher than the 2nd transmission part 64 of the 2nd cover body 62 shown in FIG. Is formed higher by the thickness of the first stopper support frame 82.

  As described above, the pressure sensors 10A and 10B according to the present embodiment are based on the design concept of the basic structure (the base frame 20A, the first and second support frames 32 and 42, and the first and second lids 52 and 62). In common, members can be shared. Then, according to the measurement pressure range, the plate thicknesses t1 and t2 of the first and second diaphragms 30 and 40 are set, and if necessary, the first stopper support frame 82 is added to the pressure sensor 10A, as shown in FIG. A wide measurement pressure range P can be covered.

  The first stopper portion 80 can be provided with a first relief portion 86 on a surface facing the second detection element 40 in order to allow vibration of the second detection element 40 formed of a piezoelectric vibrator. Thus, the first stopper portion 80 can be prevented from interfering with the second detection element 40.

  When the first diagram 50 also requires a stopper, the first stopper support frame 82 is provided between the base frame 20A and the first support frame 32, for example, in the same manner as the first stopper 80. A stopper support frame similar to the above may be provided.

  The base frame 20A, the first and second support frames 32 and 42, the first and second lids 52 and 62, or the first stopper support frame 82 forming the pressure sensors 10A and 10B are made of, for example, quartz. Can be formed.

2. Second Embodiment FIG. 6 is an exploded perspective view of a pressure sensor 10C according to a second embodiment, and FIGS. 7 and 8 are sectional views showing different sections of the pressure sensor 10C shown in FIG. In FIG. 6, the base frame 20 </ b> B has first to fourth virtual surfaces 21, 22, 23, and 24 in total, for example, two surfaces that are opposed to each other in two orthogonal axes. That is, the base frame body 20B has the third and fourth virtual surfaces 23 and 24 added as compared with the base frame body 20A of the first embodiment.

  In other words, the second embodiment shows an embodiment in which one or more virtual surfaces are added to the first embodiment. That is, the base frame 20B can further define the kth virtual plane (k is one or more integers satisfying 3 ≦ k ≦ N, and N is an integer satisfying 3 ≦ N). In this case, in addition to the structure of the first embodiment, the pressure sensor 10C further includes a kth diaphragm disposed on the surface covering the kth virtual surface and a kth detection element disposed in the sealed space. Can do. The kth diaphragm is displaced in response to the pressure in the kth pressure range including the lower pressure side than the (k-1) th pressure range with a higher resolution than the (k-1) th diaphragm, The displacement of the diaphragm is detected by the kth detection element. Thus, by increasing the number of diaphragms, the measurement pressure range P can be expanded or the resolution within the measurement pressure range P can be increased.

2.1. Embodiment of N = 4 In FIG. 6, which is an example of N = 4, the base frame 20B is the base frame 20B with respect to the first and second virtual surfaces 21 and 22, as shown in FIG. A structure similar to that of FIG. 5 is shown except that the shape is different from that of the body 20A. 6 and 7, the first and second support frame bodies 32 and 42, the first and second lid bodies 52 and 62, and the first stopper support frame body 82 having the same function as the members shown in FIG. Are denoted by the same reference numerals as those in FIG. 5 and their detailed description is omitted.

  As shown in FIGS. 6 and 8, the pressure sensor 10 </ b> C is a kth diaphragm disposed on the third and fourth virtual surfaces 23 and 24 that are the kth virtual surface and a surface that covers the kth virtual surface. It further includes third and fourth diaphragms 100 and 110 and third and fourth detection elements 120 and 130 which are k-th detection elements disposed in the airtight space 90.

  FIG. 9 shows the measurement pressure range P of the pressure sensor 10C shown in FIGS. 6 to 8 and the first to fourth pressure ranges P1 to P4 included in the measurement pressure range P. In this case, the third diaphragm 100 responds to the pressure in at least the third pressure range P3 including the low pressure side of the second pressure range P2 in the measured pressure range P with a higher resolution than the second diaphragm 60. The displacement of the third diaphragm 100 is detected by the third detection element 120.

  Similarly, the fourth diaphragm 110 responds to the pressure in at least the fourth pressure range P4 including the lower pressure side than the third pressure range P3 in the measured pressure range P with higher resolution than the third diaphragm 100. The displacement of the fourth diaphragm 110 is detected by the fourth detection element 130.

Here, the relationship between the thickness t1 of the first diaphragm 50, the thickness t2 of the second diaphragm 60, the thickness t3 of the third diaphragm 100, and the thickness t4 of the fourth diaphragm 110 is t1>t2>t3> t4. It has become. The first to fourth pressure ranges P1 to P4 measured using the first to fourth diaphragms 50, 60, 100, and 110 include regions that overlap each other. That is, the lower limit P1L of the first to third pressure ranges P1 to P3 belongs to the second to fourth pressure ranges P2 to P4, respectively, and the upper limits of the second to fourth pressure ranges P2 to P4 are the first to third pressure ranges. It belongs to each of the pressure ranges P1 to P3. The upper limit of the first pressure range P1 is, for example, 10 ⁵ Pa that matches the upper limit PU of the measurement pressure range P, and the lower limit of the fourth pressure range P4 is, for example, 10 ⁻³ Pa that matches the lower limit PL of the measurement pressure range P. .

  In each of the first to fourth diaphragms 50, 60, 100, and 110, the internal pressure of the airtight space 90 acts on one surface, the external pressure acts on the other surface, and is displaced by the internal / external differential pressure. Therefore, when this pressure sensor 10C is disposed in the measurement atmosphere, the internal pressures acting on each of the first to fourth diaphragms 50, 60, 100, 110 are equal, and the first to fourth diaphragms 50, 60, 100, 110 have the same pressure. The external pressure acting on each is also equal. Therefore, in the four measurement systems measured by each of the first to fourth diaphragms 50, 60, 100, and 110, complicated adjustment depending on the pressure difference between the four systems becomes unnecessary, and the measurement accuracy is eliminated. Will improve.

  A characteristic C21 in FIG. 9 is a pressure-strain amount characteristic when the thickness t1 of the first diaphragm 50 is, for example, 200 μm (same as the characteristic C11 in FIG. 3), and a characteristic C22 is the thickness t2 of the second diaphragm 60. For example, the pressure-strain amount characteristic when the thickness is set to 92.8 μm, the characteristic C23 is the pressure-strain amount characteristic when the thickness t3 of the third diaphragm 100 is set to, for example, 43 μm, and the characteristic C24 is the characteristic of the fourth diaphragm 110. This is a pressure-strain amount characteristic when the thickness t4 is 20 μm, for example (same as characteristic C12 in FIG. 3). The effective diameter of the diaphragm was set to φ10 mm. FIG. 9 is a logarithmic graph showing both the pressure (horizontal axis) and the amount of deflection (vertical axis) in logarithm, as in FIG.

Here, comparing FIG. 9 with FIG. 3, when measuring the pressure within the same measurement pressure range P, in FIG. 9, in particular, a pressure around 10 to 10 ⁺⁴ Pa can be detected using the characteristics C22 and C23. As a result, the pressure can be measured with a higher resolution than that in FIG. 3, so that the measurement accuracy can be further improved. Alternatively, the pressure range measured by the four diaphragms can be expanded more than the pressure range measured by the two diaphragms, and the dynamic range can be expanded.

  The pressure sensor 10C includes second and third stopper portions 140 and 150 in addition to the first stopper portion 80 that restricts the displacement of the second diaphragm 60 when a pressure higher than the upper limit of the second pressure range P2 is applied. You can also have. The second stopper portion 140 regulates the displacement of the third diaphragm 100 when a pressure higher than the upper limit of the third pressure range P3 is applied, and the third stopper portion 150 has a pressure higher than the upper limit of the fourth pressure range P4. When acted, the displacement of the fourth diaphragm 110 is restricted.

  The second stopper portion 140 has a second stopper surface 144 on the surface facing the third diaphragm 100. The gap g2 between the second stopper surface 144 and the third diaphragm 100 becomes zero when a pressure higher than the upper limit of the third pressure range P3 shown in FIG. 9 is applied, thereby restricting the displacement of the third diaphragm 100. Is done. By this second stopper portion 140, the third diaphragm 100 can be regulated so as not to bend beyond the amount of deflection substantially equal to its thickness t3 = 43 μm.

  Similarly, the third stopper portion 150 has a third stopper surface 154 on the surface facing the fourth diaphragm 110. The gap g3 between the third stopper surface 154 and the fourth diaphragm 110 becomes zero when a pressure higher than the upper limit of the fourth pressure range P4 shown in FIG. 9 is applied, thereby restricting the displacement of the fourth diaphragm 110. Is done. By this third stopper portion 150, the fourth diaphragm 110 can be regulated so as not to bend beyond the substantially same amount of deflection as its thickness t4 = 20 μm.

  More specifically, the pressure sensor 10 </ b> C can include first to fourth support frames 32, 42, 122, 132. The first support frame body 32 is on the first frame outer surface 21A of the base frame body 20B, the second support frame body 42 is on the second frame outer surface 22A of the base frame body 20B, and the third support frame body 122 is on the base frame body 20B. The fourth support frame 132 is joined to the third frame outer surface 23A and the fourth frame outer surface 24A of the base frame 20B. The first to fourth detection elements 30, 40, 120, and 130 are supported by the first to fourth support frames 32, 42, 122, and 132, respectively.

  The pressure sensor 10C further includes a first lid 52 including a first diaphragm 50, a second lid 62 including a second diaphragm 60, a third lid 102 including a third diaphragm 100, and a fourth diaphragm 110. And a fourth lid body 112 that includes the fourth lid body 112. When the first to fourth detection elements 30, 40, 120, and 130 are piezoelectric vibrators, the first to fourth transmission parts 54, 64, 104, 114 are provided.

  The pressure sensor 10 </ b> C further supports a first stopper support frame body 82 that supports the first stopper portion 80 that restricts the displacement of the second diaphragm 60, and a second stopper portion 140 that restricts the displacement of the third diaphragm 100. 2 stopper support frame 142 and the 3rd stopper support frame 152 which supports the 3rd stopper part 150 which controls the displacement of the 4th diaphragm 110 can be further included. The first stopper support frame 82 is provided between the second support frame 42 and the second lid 62, and the second stopper support frame 142 is interposed between the third support frame 122 and the third lid 102. The third stopper support frame body 152 can be provided between the fourth support frame body 132 and the fourth lid body 112.

  Here, the first to third stopper portions 80, 140, and 150 are the second to fourth detection elements 40, 120, when the second to fourth detection elements 40, 120, and 130 are piezoelectric vibrators, respectively. The first to third relief portions 86, 146, 156 may be provided at positions facing the 130.

  The airtight space 90 shown in FIGS. 7 and 8 can be formed by at least the base frame body 20B and the first to fourth lid bodies 52, 62, 102, and 112. However, as shown in FIG. When there are non-sealing surfaces on, for example, two surfaces other than the first to fourth virtual surfaces 21 to 24, the non-sealing surfaces can be sealed with the lids 160 and 162. At this time, the getter material 164 can be disposed on the inner surface side of one lid 160. The getter material 164 sets the airtight space 90 to a negative pressure after the assembly of the pressure sensor 10C.

2.2. Embodiment of N = 3 The pressure sensor 10D shown in FIGS. 10 and 11, which is an example of N = 3, is illustrated except that the fourth virtual surface 24 of the base frame 20C is closed by the lid 170, for example. 6 has the same structure. In FIG. 10, the first to third support frames 32, 42, 122, the first to third lids 52, 62, 102, and the first and second stoppers having the same functions as those shown in FIG. The frames 82 and 142 are denoted by the same reference numerals as those in FIG.

  At this time, an example of the pressure-strain amount characteristic using the first to third diaphragms 50, 60, 100 is shown in FIG.

  A characteristic C31 in FIG. 12 is a pressure-strain amount characteristic when the thickness t1 of the first diaphragm 50 is, for example, 200 μm (same as the characteristic C11 in FIG. 3 and the characteristic C21 in FIG. 9), and the characteristic C32 is the second diaphragm. 60 is a pressure-strain amount characteristic when the thickness t2 of 60 is, for example, 65 μm, and a characteristic C33 is a pressure-strain amount characteristic when the thickness t3 of the third diaphragm 100 is, for example, 20 μm (characteristic of FIG. 3). C12 and the characteristic C24 of FIG. 6). The effective diameter of the diaphragm was set to φ10 mm. FIG. 12 is a logarithmic graph showing both the pressure (horizontal axis) and the amount of deflection (vertical axis) in logarithm, as in FIGS. 3 and 6.

Here, comparing FIG. 12 with FIG. 3, when measuring the pressure within the same measurement pressure range P, in FIG. 12, in particular, a pressure around 10 to 10 ⁺³ Pa can be detected using the characteristic C <b> 32. Thereby, although the resolution is lower than that in FIG. 6, the pressure can be measured with a higher resolution than in FIG. 3, so that the measurement accuracy can be further improved.

2.3. Other Embodiments In FIG. 6 or FIG. 10, any two of the first to fourth virtual surfaces 21 to 24 of the base frame 20 </ b> B can be sealed with a lid 170 shown in FIG. 10. If it carries out like this, the pressure of the whole pressure range P can be measured by setting to the 1st, 2nd pressure range P1, P2 shown in FIG.

  In addition to the dihedron having two virtual surfaces 21 and 22 shown in FIG. 1, the side surface of the base frame body is a tetrahedron having four virtual surfaces 21 to 24 shown in FIG. 6, as well as a trihedron and pentahedron. It can also be. What is necessary is just to form a sensor part in at least 2 or more surfaces among these virtual surfaces of a polyhedron. In other words, the base frame defines at least one (M + 1) virtual plane in addition to the first to Mth virtual planes (M is an integer in 2 to 4), and at least one (M + 1) An airtight space can be formed by covering the virtual surface with a lid. By changing the lid to the sensor unit, the measurement pressure range P can be increased, or the resolution within the same measurement pressure range P can be increased. The present invention can be applied to M = 5 or more.

3. Third Embodiment FIG. 13 is an exploded perspective view of a pressure sensor 10E according to a third embodiment, and FIGS. 14 and 15 show different cross sections of the pressure sensor 10E. In the third embodiment, the same function as that of the embodiment shown in FIG. 6 is realized by changing the detection principle of the detection element from piezoelectric conversion to capacitance conversion.

  In FIG. 13, the base frame 20B and the lids 160 and 162 are the same as the members shown in FIG. The first to fourth support frame bodies 202 to 232 are joined to the first to fourth virtual surfaces 21 to 24 (first to fourth frame outer surfaces 21A to 24A) of the base frame body 20B. The first to fourth detection elements 200 to 230 supported by the first to fourth support frame bodies 202 to 323 include one electrode 200A to 230A of the pair of electrodes forming the capacitive element, and the first that supports the first electrode 200A to 230A. -It has 4th electrode support part 200B-230B.

  The first to fourth lid bodies 242 to 272 joined to the first to fourth support frame bodies 202 to 232 include first to fourth diaphragms 240 to 270. The first to fourth diaphragms 240 to 270 include the other electrodes 240A to 270A of the pair of electrodes that form the capacitive element. And if the 1st-4th diaphragms 240-270 are displaced by external pressure, the amount of gaps between one electrode 200A-230A and the other electrode 240A-270A facing them will change. As a result, the capacitance value changes, and an electrical signal corresponding to the pressure can be extracted.

  Similarly, the first and second detection elements 30, 40 shown in FIG. 1 and the first to third detection elements 30, 40, 120 shown in FIG. The other electrode may be formed on the first to third diaphragms 50, 60, 100 at a position facing the electrode.

  In the third embodiment, the first to third stopper support frames 82, 142, and 152 shown in FIGS. 4, 6, and 10 are not necessarily required. 14 and 15, gaps G1 to G4 (see FIGS. 14 and 15) between the first to fourth diaphragms 240 to 270 and the first to fourth electrode support portions 200B to 230B facing the first to fourth diaphragms 240 to 270 are as follows. This is because the first to fourth diaphragms 240 to 270 are displaced excessively to become zero, and the function of the stopper can be performed. That is, the first to third stoppers are not necessarily arranged on the first to third stopper support frames. In the present embodiment, the gaps G1 to G4 are gaps between the insulating surfaces that are wider than between the pair of electrodes. Thereby, even if the gaps G1 to G4 are each zero, the pair of electrodes are not short-circuited. In addition, one or both of the surfaces of the pair of electrodes may be covered with an insulating film.

4). Fourth Embodiment FIG. 16 shows an example structure in which the above-described pressure sensor is attached to a vacuum apparatus. FIG. 16 is a perspective view of a gauge head 300 including any one of the pressure sensors 10C to 10E shown in FIGS. 3, 10, and 13, for example.

  The gauge head 300 includes a flange 310, a substrate 320 fixed to the flange 310, and pressure sensors 10C to 10E fixed to the substrate 320. The pressure sensors 10C to 10E are fixed to the substrate 320 by wiring the wiring portion 330 connected to the first to fourth detection elements (30, 40, 120, 130, and 200 to 230) described above to the substrate 320. Is done.

  A plurality of holes 312 are formed in the circumferential direction of the flange 310. The pressure sensors 10C to 10E are arranged in the vacuum device through an opening of a vacuum device (not shown). At this time, the flange 310 is overlapped on the wall portion around the opening via the seal packing, and the flange 310 is fixed to the wall portion of the vacuum apparatus by fastening a plurality of bolts inserted through the plurality of holes 312. The Signals from the first to fourth detection elements (30, 40, 120, 130, 200 to 230) can be monitored on the atmosphere side, and the pressure in the vacuum apparatus can be monitored from the outside. The pressure sensors 10A and 10B of other embodiments can be similarly attached to the vacuum apparatus.

  Although the present embodiment has been described in detail as described above, those skilled in the art can easily understand that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings.

  For example, the detection element is preferably a tuning fork type crystal resonator, but may be any other piezoelectric transducer or the above-described capacitance detection element (one electrode of a pair of electrodes) as long as it can detect the displacement of the diaphragm. A strain gauge or the like may be used.

  10A to 10E Pressure sensor, 20A, 20B Base frame, 30 First detection element, 32 First support frame, 40 Second detection element, 42 Second support frame, 50 First diaphragm, 52 First lid, 54 1st transmission part, 60 2nd diaphragm, 62 2nd cover body, 64 2nd transmission part, 70,90 Airtight space, 80 1st stopper part, 82 1st stopper support frame, 84 1st stopper surface, 86 1st relief part, 100 3rd diaphragm, 102 3rd cover body, 104 3rd transmission part, 110 4th diaphragm, 112 4th cover body, 114 4th transmission part, 120 3rd detection element, 122 3rd support frame Body, 130 fourth detection element, 132 fourth support frame, 150 third stopper portion, 152 third stopper support frame, 154 third stopper surface, 156 third relief Part, 160, 162, 170 lid, 164 getter material, 200 to 230 first to fourth detection elements, 200A to 230A one electrode, 200B to 230B first to fourth electrode support part, 202 to 232 first to first 4th support frame, 240-270 1st-4th diaphragm, 240A-270A The other electrode, 242-272 1st-4th lid

Claims (17)

A base frame body defining at least a first virtual surface and a second virtual surface on the outer surface of the frame;
A first diaphragm disposed on a surface covering the first virtual surface;
A second diaphragm disposed on a surface covering the second virtual surface;
An airtight space formed by at least the base frame and the first and second diaphragms and having an internal pressure lower than a measurement pressure range;
A first detection element disposed in the airtight space;
A second detection element disposed in the airtight space;
Have
The first diaphragm is displaced in response to the pressure in at least the first pressure range on the high pressure side of the measurement pressure range, and the displacement of the first diaphragm is detected by the first detection element,
The second diaphragm is displaced in response to at least a second pressure range including a lower pressure side than the first pressure range in the measurement pressure range with a resolution higher than that of the first diaphragm, A pressure sensor, wherein the displacement of the second diaphragm is detected by the second detection element. In claim 1,
The first pressure range includes standard atmospheric pressure;
The upper limit of the second pressure range is a negative pressure. In claim 2,
The pressure sensor, wherein the airtight space is set to a pressure that is two orders of magnitude lower than the lower limit pressure of the measurement pressure range. In claim 2 or 3,
The pressure sensor according to claim 1, further comprising a first stopper portion that regulates displacement of the second diaphragm when a pressure higher than an upper limit of the second pressure range is applied. In claim 2 or 3,
The base frame further defines a third virtual surface on the outer surface of the frame;
The pressure sensor is
A third diaphragm disposed on a surface covering the third virtual surface;
A third detection element disposed in the airtight space;
Further comprising
The third diaphragm is displaced in response to at least a third pressure range including a lower pressure side than the second pressure range in the measurement pressure range with a resolution higher than that of the second diaphragm, A pressure sensor, wherein the displacement of the third diaphragm is detected by the third detection element. In claim 5,
A first stopper for restricting displacement of the second diaphragm when a pressure higher than the upper limit of the second pressure range is applied;
A second stopper portion that regulates displacement of the third diaphragm when a pressure higher than the upper limit of the third pressure range is applied;
A pressure sensor further comprising: In claim 5,
The base frame body further defines a fourth virtual surface on the outer surface of the frame;
The pressure sensor is
A fourth diaphragm disposed on a surface covering the fourth virtual surface;
A fourth detection element disposed in the airtight space;
Further comprising
The fourth diaphragm is displaced in response to at least a pressure in a fourth pressure range including a lower pressure side than the third pressure range in the measurement pressure range with a higher resolution than the third diaphragm, The pressure sensor, wherein the displacement of the fourth diaphragm is detected by the fourth detection element. In claim 7,
A first stopper for restricting displacement of the second diaphragm when a pressure higher than the upper limit of the second pressure range is applied;
A second stopper portion that regulates displacement of the third diaphragm when a pressure higher than the upper limit of the third pressure range is applied;
A third stopper portion for restricting displacement of the fourth diaphragm when a pressure higher than an upper limit of the fourth pressure range is applied;
A pressure sensor further comprising: In any of claims 2 to 8,
The base frame body defines at least one (M + 1) imaginary plane in addition to the first to Mth imaginary planes (M is an integer from 2 to 4),
The pressure sensor, wherein the airtight space is formed by covering the at least one (M + 1) virtual surface with a lid. In claim 2 or 3,
The base frame includes a first frame outer surface and a second frame outer surface,
The pressure sensor is
A first support frame joined to the outer surface of the first frame of the base frame and supporting the first detection element;
A second support frame joined to the outer surface of the second frame of the base frame and supporting the second detection element;
A first lid joined to the first support frame and having the first diaphragm;
A second lid joined to the second support frame and having the second diaphragm;
A pressure sensor further comprising: In claim 10,
Provided between the second support frame and the second lid, and supports a first stopper portion that regulates the displacement of the second diaphragm when a pressure higher than the upper limit of the second pressure range is applied. A pressure sensor further comprising a first stopper support frame. In claim 11,
The base frame further includes a third frame outer surface,
The pressure sensor is
A third support frame joined to the outer surface of the third frame of the base frame and supporting a third detection element;
A third lid joined to the third support frame and having a third diaphragm;
Further comprising
The third diaphragm is displaced in response to at least a third pressure range including a lower pressure side than the second pressure range in the measurement pressure range with a resolution higher than that of the second diaphragm, A pressure sensor, wherein the displacement of the third diaphragm is detected by the third detection element. In claim 12,
A second stopper portion is provided between the third support frame and the third lid and supports a second stopper portion that regulates displacement of the third diaphragm when a pressure higher than the upper limit of the third pressure range is applied. A pressure sensor further comprising a second stopper support frame. In claim 13,
The base frame further includes a fourth frame outer surface,
The pressure sensor is
A fourth support frame joined to the outer surface of the fourth frame of the base frame and supporting a fourth detection element;
A fourth lid joined to the fourth support frame and having a fourth diaphragm;
Further comprising
The fourth diaphragm is displaced in response to at least a pressure in a fourth pressure range including a lower pressure side than the third pressure range in the measurement pressure range with a higher resolution than the third diaphragm, The pressure sensor, wherein the displacement of the fourth diaphragm is detected by the fourth detection element. In claim 14,
Provided between the fourth support frame and the fourth lid, and supports a third stopper portion that regulates the displacement of the fourth diaphragm when a pressure higher than the upper limit of the fourth pressure range is applied. A third stopper support frame that
A pressure sensor further comprising: In any of claims 11 to 15,
Each of the first and second detection elements is formed by a piezoelectric vibrator,
The first lid has a first transmission part that transmits the displacement of the first diaphragm to the first detection element;
The second lid has a second transmission part that transmits the displacement of the second diaphragm to the second detection element;
The first stopper portion is
A stopper surface formed on the surface facing the second diaphragm;
An escape portion formed on a surface facing the second detection element and allowing vibration of the second detection element;
A pressure sensor comprising:   A vacuum apparatus comprising the pressure sensor according to claim 2, which is disposed so as to face a region to be subjected to atmosphere-vacuum replacement.

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