Diaphragm pressure gauge and compound pressure gauge

Abstract

A diaphragm pressure gauge and a compound pressure gauge are provided, which are configured at a measured pressure and are capable of measuring a pressure below atmospheric pressure without depending on an ambient temperature and a gas type. The diaphragm pressure gauge (10) has a structure body (40) configured at a measured pressure (Pm), two diaphragms (20) arranged in opposition and attached to the structure body, and a detection element (30) fixed to the two diaphragms and detecting displacement of the two diaphragms. When one of two surfaces of each of the two diaphragms is an opposing surface and the other of the two surfaces is a non-opposing surface, with respect to the structure body and the two diaphragms, a space facing one of the opposing surface and the non-opposing surface is made to be a hermetic space (40A) maintained at a reference vacuum (Pr), and the measured pressure is made to act on the other of the opposing surface and the non-opposing surface.

Description

Technical Field

[0001] This invention relates to a diaphragm pressure gauge and a composite pressure gauge configured under the pressure being measured. Background Technology

[0002] A vacuum gauge configured under the pressure to be measured is called a bare vacuum gauge, and ionization vacuum gauges (hot cathode ionization vacuum gauges or cold cathode ionization vacuum gauges) as described in Patent Documents 1 and 2 are known. On the other hand, as shown in Patent Document 3, a diaphragm pressure gauge using a diaphragm is configured in an atmospheric pressure atmosphere, with the pressure to be measured acting on one side of the diaphragm configured in an airtight container, and a reference vacuum acting on the other side.

[0003] In addition, as composite vacuum gauges capable of measuring high vacuum regions from an atmospheric barometer, there are known composite vacuum gauges that combine an ionization vacuum gauge, a Pirani vacuum gauge, and an atmospheric pressure sensor, or composite vacuum gauges that combine an ionization vacuum gauge and a quartz triboelectric vacuum gauge. Devices using hot cathode ionization vacuum gauges as ionization gauges offer superior accuracy compared to cold cathode ionization vacuum gauges and are used for process pressure control.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-096763

[0007] Patent Document 2 Japanese Patent Application Publication No. 2007-024849

[0008] Patent Document 3: Japanese Patent No. 6744636 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] Cold cathode ionization vacuum gauges are less accurate than hot cathode ionization vacuum gauges, especially at higher pressures, due to electrode contamination and wear caused by discharge phenomena. However, consumables are easily replaceable. While hot cathode ionization vacuum gauges do not have the aforementioned problems of cold cathode ionization vacuum gauges, they have a filament that serves as a heat source. Ionization vacuum gauges used as bare vacuum gauges (hot cathode or cold cathode ionization vacuum gauges) cannot be used in low-vacuum measurement areas. One reason is that at high oxygen partial pressures, the electrodes in cold cathode ionization vacuum gauges wear out, and the filament in hot cathode ionization vacuum gauges wears out, sometimes even breaking. Another reason is that more molecules collide with electrons emitted from the filament, increasing the ion current and reducing sensitivity. On the other hand, diaphragm pressure gauges, when not used as bare vacuum gauges and placed in an atmospheric pressure atmosphere, show readings that vary depending on the ambient temperature. Especially at low pressures, the measurement error increases, making accurate pressure measurements impossible.

[0011] Furthermore, conventional composite pressure gauges capable of measuring high vacuum regions from atmospheric pressure gauges require the combination of at least three devices (thermocathode ionization vacuum gauge, Pirani vacuum gauge, and atmospheric pressure sensor). Alternatively, the pressure readings of Pirani vacuum gauges or quartz triboelectric vacuum gauges used in measuring low vacuum regions of composite pressure gauges are affected by the composition of process gases due to sensitivity differences caused by gas types, making it difficult to measure the accurate real pressure in real time.

[0012] The purpose of this invention is to provide a diaphragm pressure gauge configured under the pressure to be measured, which can measure pressures below atmospheric pressure regardless of ambient temperature or gas type.

[0013] Another object of the present invention is to provide a composite pressure gauge that can combine two pressure gauges, including the diaphragm pressure gauge described above, to measure a wide range of pressures from atmospheric pressure to high vacuum, independent of ambient temperature.

[0014] Methods for solving problems

[0015] (1) One aspect of the present invention relates to a diaphragm pressure gauge having: a structure disposed under a pressure to be measured; two diaphragms disposed opposite each other and mounted on the structure; and a detection element fixed to the two diaphragms and detecting the displacement of the two diaphragms, wherein, with respect to the structure and the two diaphragms, the space facing one of the opposing surfaces and the other of the opposing surfaces is made into an airtight space maintained as a reference vacuum, and the pressure to be measured is applied to the other of the opposing surfaces and the other of the opposing surfaces.

[0016] According to one aspect of the invention, two opposing diaphragms are respectively subjected to a reference vacuum on one side and the pressure to be measured on the other, displacing according to the pressure difference. Therefore, regardless of the gas type, the force acting on a certain area of ​​the gas molecules is measured, thus enabling accurate detection of the gas pressure. The displacements of the two diaphragms are opposite to each other and equal in absolute value; therefore, even if each displacement is as small as, for example, 7 μm to 10 μm, the sensitivity is doubled. The displacements of the two diaphragms are converted from a signal from a detection element into a pressure-proportional signal. The detection element can be a piezoelectric element, an electrostatic capacitance detection element, etc. In particular, when the piezoelectric element is a quartz oscillator or a double tuning fork type quartz oscillator, the displacements of the two diaphragms are detected as a frequency change of the quartz oscillator, resulting in an output signal proportional to the pressure being measured. This diaphragm pressure gauge can measure pressures from atmospheric pressure to a reference vacuum.

[0017] Here, the diaphragm pressure gauge is positioned at the pressure being measured, and unlike a thermionic vacuum gauge, it does not require a heat source. Therefore, the temperature of the measuring atmosphere is always the same as the temperature of the atmosphere at the measured pressure. Consequently, the measurement error relative to ambient temperature is small at the measured pressure from atmospheric pressure to low vacuum. The higher the measured pressure, the better the vacuum insulation effect relative to ambient temperature. Therefore, it is possible to accurately measure the measured pressure from atmospheric pressure to a reference vacuum.

[0018] (2) In one embodiment (1) of the present invention, the structure may include: an inner structure supporting the two opposing diaphragms; and an outer structure internally supporting the inner structure and including openings that expose the non-opposing surfaces of the two diaphragms in the atmosphere of the pressure being measured. Thus, the airtight space hermetically surrounded by the two diaphragms, the inner structure, and the outer structure is set as the reference vacuum, which acts on the opposing surfaces, and the pressure being measured acts on the non-opposing surfaces.

[0019] (3) In one embodiment (1) of the present invention, the structure may have: an outer structure, the airtight space inside which is set to the reference vacuum; and an inner structure disposed within the outer structure and insulated by the reference vacuum. The inner structure may include: an inlet tube having an inlet for the gas at the measured pressure at a protruding end extending outward from the outer structure; and an inner chamber set to the measured pressure via the inlet tube. In this case, the two diaphragms are configured as part of the partition wall of the inner chamber, the measured pressure acts on the opposing surface, and the reference vacuum acts on the non-opposing surface.

[0020] (4) In one embodiment (3) of the invention, the inner chamber may include: a first chamber set to the pressure to be measured via the inlet tube; a second chamber communicating with the interior of the outer structure and hermetically isolated from the first chamber; and a bellows dividing the first chamber and the second chamber and connected to the two diaphragms, deformable to allow displacement of the two diaphragms. In this case, the opposing surfaces of the two diaphragms are arranged facing the interior of the first chamber, and the detection element is disposed in the second chamber.

[0021] (5) In one embodiment (1) to (4) of the present invention, the structure can be mounted on a fixing member with a thermal insulator in between, the fixing member configuring and fixing the structure under the measured pressure. In this way, even if the ambient temperature of the fixing member changes, the thermal insulator can be used to block the conduction of the ambient temperature in the solid.

[0022] (6) In one embodiment (1) to (5) of the present invention, an anti-adhesion shield and / or a heat shield may also be provided, which surround the structure and allow the gas to be measured to pass through at least a portion thereof. In this way, even when a vapor deposition source is configured at the pressure to be measured, particles and heat from the vapor deposition source can be blocked.

[0023] (7) In one embodiment (1) to (6) of the present invention, the detection element may be a quartz oscillator. A quartz oscillator is capable of measuring pressures from atmospheric pressure to a high vacuum region, for example, 10... -2 The measured pressure is Pa.

[0024] (8) Another aspect of the present invention relates to a composite pressure gauge having a diaphragm pressure gauge of one aspect (7) of the present invention and an ionization vacuum gauge disposed at the pressure to be measured, wherein the measuring area of ​​the diaphragm pressure gauge overlaps with the measuring area of ​​the ionization vacuum gauge.

[0025] According to another aspect of the invention, the measurement area of ​​the diaphragm pressure gauge overlaps with the measurement area of ​​the ionization vacuum gauge, thus enabling the measurement of pressures ranging from atmospheric pressure to high vacuum or ultra-high vacuum using a single composite pressure gauge. The ionization vacuum gauge can be either a hot cathode or a cold cathode, but from an accuracy point of view, a hot cathode is preferred. Since the composite pressure gauge is positioned at the measured pressure, the temperature of the measuring atmosphere is always the same as the temperature of the atmosphere at the measured pressure. Here, at measured pressures ranging from atmospheric pressure to low vacuum, the measurement error relative to temperature variations in the external air is small, and the measured pressures within this range can be measured using a diaphragm pressure gauge of one aspect of the invention without a heat source. On the other hand, the measured pressures at high vacuum are primarily measured using an ionization vacuum gauge, particularly a hot cathode ionization vacuum gauge incorporating a heat source. While ionization vacuum gauges exhibit sensitivity variations due to the type of gas, the relative accuracy of the pressure has the same reliability as the reading accuracy because a proportional relationship is maintained between the ion current (measured value) and the pressure. Therefore, it is possible to accurately measure measured pressures ranging from atmospheric pressure to high vacuum or ultra-high vacuum.

[0026] (9) In another embodiment (8) of the present invention, the measuring region of the diaphragm pressure gauge and the measuring region of the ionization vacuum gauge may overlap in the range of 0.01 to 10.0 Pa. In this case, the diaphragm pressure gauge can use the range from atmospheric pressure to 0.01 Pa as its measuring region, and the ionization vacuum gauge can use a vacuum region lower than 10.0 Pa as its measuring region. This overlapping region may be 0.1 to 10.0 Pa or 0.1 to 1.0 Pa.

[0027] (10) In other embodiments (8) or (9) of the invention, the ion current value of the ionization vacuum gauge may be converted to a nitrogen equivalent value, and the measured value of the diaphragm pressure gauge may be graded to match the upper limit of the nitrogen equivalent value of the ionization vacuum gauge. In this way, the measured value from atmospheric pressure to high vacuum or ultra-high vacuum exhibits a linear characteristic. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view showing the diaphragm pressure gauge according to the first embodiment of the present invention.

[0029] Figure 2 It is a characteristic graph that shows the correlation between the measured pressure and the insulation effect.

[0030] Figure 3 (A) Figure 3 (C) represents Figure 1 A diagram showing an example of a diaphragm pressure gauge.

[0031] Figure 4 (A) and Figure 4 (B) means Figure 1 Figures showing other examples of diaphragm pressure gauges.

[0032] Figure 5 It means Figure 1 The figure shows another example of a diaphragm pressure gauge.

[0033] Figure 6 It means Figure 1 A cross-sectional view of yet another example of a diaphragm pressure gauge.

[0034] Figure 7 yes Figure 6 The diagram shows a cross-sectional view of the main parts of the diaphragm pressure gauge.

[0035] Figure 8 This is a cross-sectional view showing the composite pressure gauge according to the second embodiment of the present invention.

[0036] Figure 9 This is a characteristic diagram representing the range of the pressure being measured by the composite pressure gauge.

[0037] Figure 10 This refers to the difference in sensitivity caused by the type of gas in the ionization vacuum gauge within a compound pressure gauge, and is called... Figure 9 The basic characteristic diagram of its properties.

[0038] Figure 11 It indicates a change. Figure 8 A diagram showing a variation of the filament configuration.

[0039] Symbol Explanation

[0040] 10…Diaphragm pressure gauge, 20…Diaphragm, 20A…Opposing surface, 20B…Non-opposing surface, 30…Detection element, 40…Structure, 40A…Airtight space serving as reference vacuum, 41, 44…Exhaust pipe, 42…Pump housing, 43, 45…Intake pump, 50…Inner structure, 52…Outer structure, 60…Outer structure, 70…Inner structure, 71…Rigid body, 71A…Opening, 72…Inlet pipe, 74…Inner chamber, 80…First chamber, 82…Second chamber, 84…Bellbell, 90…Fixed component, 92…Thermal insulator, 94…Circuit block, 100…Ionization vacuum gauge, 110…Connecting component, 120…Shielding component, 130…Thermal shielding component, 200…Combined pressure gauge, Pm…Measured pressure, Pr…Reference vacuum Detailed Implementation

[0041] In the following disclosure, various different implementations and embodiments for carrying out different features of the presented subject matter are provided. These are, of course, merely examples and are not intended to be limiting. Furthermore, in this disclosure, references to numbers and / or characters are sometimes repeated in various examples. Such repetition is for clarity and does not itself need to relate to the various implementations and / or the structures described. Moreover, when described as a first element and a second element "connected" or "linked," such description includes implementations where the first and second elements are directly connected or linked to each other, and also includes implementations where the first and second elements are indirectly connected or linked to each other by having one or more other elements in between.

[0042] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0043] 1. First Implementation Method

[0044] Figure 1This invention describes a diaphragm pressure gauge 10 according to a first embodiment of the present invention. The diaphragm pressure gauge 10 includes two diaphragms 20, a sensing element 30, and a structure 40. The structure 40 is positioned at the pressure to be measured (Pm). The two diaphragms 20 are arranged opposite each other and mounted on the structure 40. The sensing element 30 is fixed to the two diaphragms 20. A flange 90 is a fixing component for positioning and fixing the structure 40 at the pressure to be measured (Pm). The flange 90 is mounted, for example, in a vacuum chamber, thereby positioning the structure 40 at the pressure to be measured (Pm). The structure 40 can be mounted on the flange 90 via a thermal insulator 92. Thus, even if the flange 90 is affected by ambient temperature, the thermal insulator 92 can block the conduction of that ambient temperature in the solid. A circuit block 94 is fixed on the atmospheric pressure side of the flange 90, and this circuit block 94 is provided with a drive circuit or signal output circuit, etc., for driving the sensing element 30. The sensing element 30 that detects the displacement of the two diaphragms 20 is, for example, a piezoelectric element such as an oscillator. The oscillator 30 is vibrated by an oscillating circuit that serves as a drive circuit, and its resonant resistance Z is determined. The gas pressure can be determined by the difference ΔZ (=Z-Z0) between the measured resonant resistance Z and the inherent resonant resistance Z0 (the value under high vacuum).

[0045] Let one of the two sides of each of the two diaphragms 20 be the opposing side 20A, and the other side be the non-opposing side 20B. The structure 40 and the two diaphragms 20 are configured as an airtight space 40A, which is used to contain one of the opposing side 20A and the non-opposing side 20B (in... Figure 1 The space facing the opposing surface 20A is maintained at a reference vacuum (Pr). The pressure to be measured (Pm) is applied to the other side of the opposing surface 20A and the non-opposing surface 20B. Figure 1 The middle plane is 20B, which is not the opposite plane.

[0046] According to this embodiment, two opposing diaphragms 20 are subjected to a known reference vacuum (Pr) on one of their opposing surfaces 20A, and to a measured pressure (Pm) on their non-opposing surface 20B, displacing according to the pressure difference. The displacements of the two diaphragms 20 are opposite to each other and have equal absolute values; therefore, even if each displacement is as small as, for example, 7 μm to 10 μm, the sensitivity is doubled. Furthermore, by fixing the detection element 30 between the two diaphragms 20, the pressure measurement error caused by the weight of the diaphragms themselves, as in conventional diaphragm pressure gauges, can be eliminated. That is, errors that may arise due to the installation posture of the vacuum gauge are eliminated. Thus, the displacement of the two diaphragms 20 is converted into a pressure-proportional signal by the piezoelectric element 30. In particular, when the piezoelectric element 30 is a quartz oscillator or a double tuning fork type quartz oscillator, the displacement of the two diaphragms 20 is detected as a frequency change of the quartz oscillator, resulting in an output signal proportional to the measured pressure (Pm). Therefore, it is possible to measure the pressure (Pm) between atmospheric pressure and a reference vacuum.

[0047] Here, the structure 40 of the diaphragm pressure gauge 10 is positioned at the pressure to be measured (Pm), and unlike the ionization vacuum gauge, it does not require a heat source, so the temperature of the measuring atmosphere is always the same as the temperature of the atmosphere at the pressure to be measured (Pm). Figure 2 This indicates the correlation between the measured pressure (Pm) and the insulation effect. Typically, the pressure is below atmospheric pressure (1.013 × 10⁻⁶). 5 Vacuum regions of 10 Pa are classified as low vacuum (10 Pa). 5 ~10 2 Pa), medium vacuum (10 2 ~10 -1 Pa), high vacuum (10 -1 ~10 -5 Pa). For example Figure 2 As shown, the pressure being measured (Pm) is from atmospheric pressure (approximately 10). 5 Pa) to high vacuum (10 -2 At a pressure of Pa, the insulation effect changes from 0% to 100% with the measured pressure (Pm), for example, at a pressure of 10 Pa. -2 Pa is near the high vacuum side (10) -2 Pa~10 -5 The insulation effect is 100% (Pa). That is, in the high vacuum region (10 Pa) where the measured pressure (Pr) is, the insulation effect is 100%. -1 ~10 -5 At a pressure of 10 Pa, the vacuum insulation effect against external air temperature is good. On the other hand, compared with high vacuum (10 Pa), it has a better effect against external air temperature. -1 ~10 -5 Compared to atmospheric pressure (Pa), from atmospheric pressure to medium vacuum (10 Pa) 5 ~10 -1At the measured pressure (Pm) of Pa, the measurement error associated with pressure variations relative to temperature is small. Therefore, from atmospheric pressure to medium vacuum (10 Pa), the measurement error is small. 5 ~10 -1 Even with a small insulation effect at the measured pressure (Pm) of Pa, measurement errors associated with pressure variations relative to temperature can be ignored. Therefore, it is possible to measure the measured pressure (Pm) from atmospheric pressure to high vacuum with high accuracy.

[0048] like Figure 3 (A) to Figure 3 As shown in (C), the structure 40 may have an exhaust pipe 41 communicating with the airtight space 40A and a pump housing 42. An inactive intake pump 43 is housed in the pump housing 42. For example, with one side of the cubic structure 40 open, two diaphragms 20 are installed on the structure 40, and the two ends of the oscillator 30 are fixed to the two diaphragms 20. Then, a cover is fixed to the open side of the structure 40. A heater is wound around the pump housing 42, and the intake pump 43 is activated, for example, at 500°C for 1 hour, during which time exhaust is pumped from the open end of the exhaust pipe 41 using a vacuum pump. Afterward, the pump housing 42 is cooled, and the end of the exhaust pipe 41 is sealed. In this state, when the intake pump 43 is operating, the airtight space 40A is set to, for example, 10... -5 The reference vacuum (Pr) is Pa.

[0049] Or, such as Figure 4 (A) and Figure 4 As shown in (B), the structure 40 may also have an exhaust pipe 44 that communicates with the airtight space 40A. The exhaust pipe 44 can also serve as a housing for the intake pump 45.

[0050] Or, such as Figure 5 As shown, the structure 40 may also include an inner structure 50 and an outer structure 52. The inner structure 50 supports two opposing diaphragms 20. The outer structure 52 internally supports the inner structure 50 and may include an opening 52A that exposes the non-opposing surfaces 20B of the two diaphragms 20 in an atmosphere of the measured pressure (Pm). Thus, the airtight space 40A, hermetically surrounded by the two diaphragms 20, the inner structure 50, and the outer structure 52, is set to a reference vacuum (Pr). In this case, the reference vacuum (Pr) acts on the opposing surfaces 20A, and the measured pressure (Pm) acts on the non-opposing surfaces 20B. After the two diaphragms 20 and the sensing element 30 are installed in the inner structure 50, the inner structure 50 is positioned and fixed within the outer structure 52. Thus, with... Figure 3 (A) Figure 3 Compared to the structure 40 shown in (C), the assembly process becomes easier.

[0051] Or, such as Figure 6 As shown, the structure 40 may also have an outer structure 60 with an internal airtight space 40A set to a reference vacuum (Pr), and an inner structure 70 disposed within the outer structure 60 and insulated by the reference vacuum (Pr). The inner structure 70 may include: an inlet pipe 72 having an inlet for gas at the pressure to be measured at a protruding end that protrudes outward from the outer structure 60; and an inner chamber 74 set to the pressure to be measured (Pm) via the inlet pipe 72. In this case, two diaphragms 20 are configured as part of the partition walls of the inner chamber 74, the pressure to be measured (Pm) acts on the opposing surface 20A, and the reference vacuum (Pr) acts on the non-opposing surface 20B.

[0052] like Figure 6 as well as Figure 7 As shown, the inner chamber 74 may include: a first chamber 80, which is set to the pressure to be measured (Pm) via an inlet tube 72; a second chamber 82, which communicates with the airtight space 40A inside the outer structure 60 and is airtightly isolated from the first chamber 80; and a bellows 84, which divides the first chamber 80 and the second chamber 82 and is connected to two diaphragms 20, and is deformable to allow displacement of the two diaphragms. In this case, the opposing surfaces 20A of the two diaphragms 20 are arranged facing the interior of the first chamber 80, and the piezoelectric element 30 is disposed in the second chamber 82.

[0053] The inner structure 70 can also be equipped with two rigid bodies 71 that connect the two diaphragms 20 to the bellows 84. For example... Figure 7 As shown, each rigid body 71 can have an opening 71A that connects the airtight space 40A, set to a reference vacuum (Pr), with the second chamber 82. Thus, the bellows 84 is set to a reference vacuum Pr via the central holes formed in the two diaphragms 20 and the opening 71A. In this way, the piezoelectric element 30 is positioned under the reference vacuum (Pr), and the airtight space 40A surrounding it also becomes a reference vacuum (Pr). Therefore, the heat insulation effect becomes... Figure 2 Characteristic C2 is unaffected by temperature. For example, even in the presence of heat sources such as evaporation sources at the measured pressure, the effect of temperature is minimal. This further improves the accuracy of pressure measurement.

[0054] 2. Second Implementation Method

[0055] The composite pressure gauge 200 of the second embodiment of the present invention includes the diaphragm pressure gauge 10 and the ionization vacuum gauge 100 of the first embodiment of the present invention. The diaphragm pressure gauge 10 and the ionization vacuum gauge 100 are connected by a connecting member 110 and are both configured at the pressure to be measured (Pm). The connecting member 110 is fixed to the vacuum chamber.

[0056] Here, the ionization vacuum gauge 100 is configured as a hot cathode ionization vacuum gauge (a type that extracts thermionic electrons by heating the filament) or a cold cathode ionization vacuum gauge (a type that extracts electrons by emitting electrons through an electric field). Here, the hot cathode ionization vacuum gauge 100 will be described as an example. For example, the hot cathode ionization vacuum gauge 100 has a filament 102, a grid 104, and a collector 106. When the filament 102 is energized, electrons fly out of the filament 102. The electrons flying out of the filament 102 repeatedly circulate towards the grid 104, but in this process, the electrons ionize the gas in the measured pressure (Pm). The higher the measured pressure (Pm), the more molecules and atoms are ionized. Under the condition that the current (emission current) of the thermionic electrons emitted from the filament 102 is constant, the pressure can be indirectly measured by measuring the ion current flowing into the collector 106, which is negatively biased to absorb the ionized molecules and atoms.

[0057] Here, the hot cathode ionization vacuum gauge 100, as Figure 11 As shown, the filament 102 is more preferably disposed on the outer side of the spiral grid 104. There may also be a single filament 102 disposed on the outer side. This way, even if the measured pressure (Pm) is relatively high, the decrease in sensitivity can be suppressed. This is because the flow of molecules and atoms ionized by electrons emitted from the filament 102 into the collector 106 inside the spiral grid 104 is suppressed. Furthermore, molecules and atoms ionized by electrons emitted from the filament 102 can also flow into the housing of the thermionic vacuum gauge 100, so even if the measured pressure (Pm) is relatively high, the ion current will not increase excessively.

[0058] Here, Figure 9 and Figure 10 This indicates the pressure characteristics of the composite pressure gauge 200. Figure 10 This refers to the difference in sensitivity of the ion current (characteristic C4') of the ionization vacuum gauge 100 in the composite pressure gauge 200 caused by the type of gas. Figure 9 The basic characteristic diagram is shown. However, in the ionization vacuum gauge 100, a proportional relationship is maintained between the ion current and the pressure, thus the relative accuracy of the pressure has the same reliability as the reading accuracy. Therefore, the method used in this embodiment... Figure 9 In the characteristic of the diaphragm pressure gauge 10, the measured value (characteristic C3) is converted in the software to the upper limit ion current value of characteristic C4 of the ionization vacuum gauge 100 (a specific gas conversion value of the ion current value that has a proportional relationship with pressure regardless of the gas type, such as the nitrogen conversion value). Therefore, in the composite pressure gauge 200 using the diaphragm pressure gauge 10 and the ionization vacuum gauge 100, the displayed pressure of the ionization vacuum gauge 100 can be obtained regardless of the composition of the measured gas, thus providing a true pressure.

[0059] like Figure 9 As shown, the diaphragm pressure gauge 10 will, for example, draw pressure from atmospheric pressure (10 +5 Pa) to medium vacuum (10 -2 The ionization vacuum meter 100 uses a measurement range of, for example, from medium vacuum (1 Pa) to extremely high vacuum (10 Pa). -7 Pa) is used as the measurement range. Thus, the composite pressure gauge 200 can measure, for example, pressure from atmospheric pressure (10 Pa). +5 From Pa) to extremely high vacuum (10) -7 The measurement range is defined as 0.01 to 1.0 Pa. In this example, the measurement area of ​​the diaphragm pressure gauge 10 overlaps with that of the ionization vacuum gauge 100 within the range of 0.01 to 1.0 Pa, but it is not limited to this. This overlapping area can be 0.01 to 10.0 Pa, or 0.1 to 1.0 Pa, etc. In this embodiment, the measurement range of the diaphragm pressure gauge 10 is expanded, so by using the composite pressure gauge 200 composed of the diaphragm pressure gauge 10 and the ionization vacuum gauge 100, it is possible to measure pressures from atmospheric pressure to ultra-high vacuum (e.g., 10 Pa). -7 The area of ​​Pa).

[0060] Since the composite pressure gauge 200 is configured at the measured pressure (Pm), the temperature of the measuring atmosphere is always the same as the temperature of the atmosphere at the measured pressure (Pm). Here, the measurement error relative to the temperature variation of the external air is small at the measured pressure (Pm) from atmospheric pressure to low vacuum, and the measured pressure (Pm) in this range can be measured using a diaphragm pressure gauge of one aspect of the present invention without a heat source. On the other hand, the measured pressure (Pm) at high vacuum or ultra-high vacuum is mainly measured by a thermionic vacuum gauge 100 containing a heat source. In the thermionic vacuum gauge 100, the difference in sensitivity caused by the gas type ensures a proportional relationship between the ion current and the pressure, thus the relative accuracy of the pressure has the same reliability as the reading accuracy. Therefore, the measured pressure (Pm) from atmospheric pressure to high vacuum or ultra-high vacuum can be accurately measured.

[0061] Here, the filament 102 of the hot cathode ionization vacuum gauge 100 may not be continuously energized during the measurement, but rather the energization of the filament 102 may be turned on / off based on the pressure value measured by the diaphragm pressure gauge 10. For example, if the pressure value measured by the diaphragm pressure gauge 10 becomes Figure 9 When the upper limit of the measurement range of the hot cathode ionization vacuum gauge 100 is reached, the filament 102 can be energized before or after the upper limit of the measurement range, or below the upper limit of the measurement range. In this way, the adverse effects of the filament 102 as a heat source on the diaphragm pressure gauge 10 can be reduced.

[0062] Alternatively, the lower limit of measurement (below the diaphragm pressure gauge 10) can also be determined using the hot cathode ionization vacuum gauge 100. Figure 9 The middle is 10-2 When the measured pressure (Pm) is less than the lower limit of the diaphragm pressure gauge 10, zero-point calibration is performed. This is because the measured value of the diaphragm pressure gauge 10 should be zero at the measured pressure (Pm) less than the lower limit of the diaphragm pressure gauge 10.

[0063] like Figure 8 As shown, a shielding member 120, serving as an anti-adhesion shield and / or a heat shield, can also be provided surrounding the structure 40. The shielding member 120 allows the gas to be measured to pass through at least a portion of it, thus enabling the inner side of the shielding member 120 to be the pressure of the gas to be measured. Figure 8 In this design, the shielding component 120 is entirely formed of a porous sintered body, such as ceramic. This ensures the permeability of the gas being measured. Furthermore, even when a vapor deposition source is positioned at the measured pressure (Pm) outside the shielding component 120, particles and heat from the vapor deposition source can be blocked by the shielding component 120. That is, the shielding component 120 functions as both an anti-adhesion shield and a heat shield; the anti-adhesion shield blocks particles from the vapor deposition source to prevent film formation on the diaphragm pressure gauge 10, and the heat shield prevents heat from the vapor deposition source (heat source) from being conducted to the diaphragm pressure gauge 10. The shielding component 120 can also be a non-permeable heat shield with filters or baffles (barriers) in at least a portion. In this case, filters or baffles are used to ensure both permeability and the function of an anti-adhesion shield.

[0064] like Figure 8 As shown, a heat shield 130 can be added to the connecting member 110. This heat shield 130 can be, for example, formed by a baffle. In this way, heat transfer from the heat source (filament) of the thermionic vacuum gauge 100 to the diaphragm pressure gauge 10 can be prevented by the heat shield 130.

[0065] This invention is not limited to the embodiments described above, and various modifications can be implemented within the scope of the spirit of this invention. For example, it can surround... Figure 1 The structure 40 shown is further provided as an anti-adhesion shield and / or a heat shield. Figure 8 Shielding component 120.

Claims

1. A diaphragm pressure gauge, comprising: A structure configured under the pressure being measured; Two diaphragms are configured opposite each other and installed on the structure; and The detection element has its two ends fixed to the two diaphragms and detects the displacement of the two diaphragms. The two diaphragms each have two opposing surfaces and two non-opposing surfaces. The airtight space surrounded by the structure and the two diaphragms serves as a reference vacuum. The two diaphragms are displaced according to the pressure difference between the measured pressure acting on the two non-opposing surfaces and the reference vacuum acting on the two opposing surfaces. The absolute values ​​of the displacements of the two diaphragms are equal and opposite to each other.

2. The diaphragm pressure gauge according to claim 1, wherein, The structure includes: The inner structure supports the two opposing diaphragms; and An outer structure that internally supports the inner structure and includes openings that expose the non-opposing surfaces of the two diaphragms in the atmosphere at the pressure being measured. The airtight space, which is airtightly surrounded by the two diaphragms, the inner structure, and the outer structure, is set as the reference vacuum.

3. A diaphragm pressure gauge, comprising: A structure configured under the pressure being measured; Two diaphragms are configured opposite each other and installed on the structure; as well as A detection element, fixed to the two diaphragms, detects the displacement of the two diaphragms. The structure has: The outer structure, whose internal airtight space is set to a reference vacuum; and The inner structure, supported by the outer structure, is disposed within the outer structure and insulated by the reference vacuum. The inner structure includes: An inlet tube has an inlet at a protruding end that extends outward from the outer structure, opening into the atmosphere in which the structure is disposed to introduce the gas whose pressure is to be measured. as well as The inner chamber, via the inlet tube, is set to the pressure being measured. The two diaphragms are configured as part of the partition wall of the inner chamber, comprising two opposing surfaces and two non-opposing surfaces. The diaphragms are displaced according to the pressure difference between the measured pressure acting on the two opposing surfaces and the reference vacuum acting on the two non-opposing surfaces. The absolute values ​​of the displacements of the two diaphragms are equal and opposite to each other.

4. The diaphragm pressure gauge according to claim 3, wherein, The inner chamber includes: The first chamber is set to the pressure to be measured via the inlet tube; The second chamber communicates with the interior of the outer structure and is airtightly isolated from the first chamber; and A bellows, which divides the first chamber and the second chamber and is connected to the two diaphragms, is deformable to allow displacement of the two diaphragms. The opposing surfaces of the two diaphragms are arranged facing the interior of the first chamber. The detection element is disposed in the second chamber.

5. The diaphragm pressure gauge according to claim 1 or 3, wherein, The structure is mounted on a fixing component via a thermal insulator, which configures and fixes the structure under the measured pressure.

6. The diaphragm pressure gauge according to claim 1 or 3, wherein, The diaphragm pressure gauge also has an anti-adhesion shield and / or a thermal shield that surrounds the structure and allows the gas to be measured to pass through at least a portion of it.

7. The diaphragm pressure gauge according to claim 1 or 3, wherein, The detection element is a quartz oscillator.

8. A composite pressure gauge, comprising: The diaphragm pressure gauge according to claim 7; and An ionization vacuum gauge configured at the pressure being measured. The measuring area of ​​the diaphragm pressure gauge overlaps with the measuring area of ​​the ionization vacuum gauge.

9. The composite pressure gauge according to claim 8, wherein, The measuring area of ​​the diaphragm pressure gauge overlaps with the measuring area of ​​the ionization vacuum gauge in the range of 0.01 to 10.0 Pa.

10. The composite pressure gauge according to claim 8, wherein, The ion current value of the ionization vacuum gauge is converted into a nitrogen conversion value, and the measured value of the diaphragm pressure gauge is converted to match the upper limit of the nitrogen conversion value of the ionization vacuum gauge.

11. A pressure measurement method based on a diaphragm manometer, wherein, A diaphragm pressure gauge is configured under the pressure to be measured. The diaphragm pressure gauge has a structure; two diaphragms are oppositely arranged and installed on the structure, the two diaphragms comprising two opposing surfaces and two non-opposing surfaces; and a sensing element, the two ends of which are fixed to the two diaphragms, and which detects the displacement of the two diaphragms. The structure consisting of the two diaphragms and the two diaphragms together establish the space facing the two opposing surfaces as an airtight space maintained at a reference vacuum. The pressure to be measured is applied to the two non-opposing surfaces. The two diaphragms are displaced according to the pressure difference between the measured pressure and the reference vacuum, and the absolute values ​​of the displacements of the two diaphragms are equal and opposite to each other.

12. A pressure measurement method based on a diaphragm manometer, wherein, The diaphragm pressure gauge has the following features: A structure configured under the pressure being measured; Two diaphragms are configured opposite each other and installed on the structure; as well as A detection element, fixed to the two diaphragms, detects the displacement of the two diaphragms. The structure has: The outer structure, whose internal airtight space is set to a reference vacuum; and The inner structure, supported by the outer structure, is disposed within the outer structure and insulated by the reference vacuum. The inner structure includes: An inlet tube has an inlet at a protruding end that extends outward from the outer structure, opening into the atmosphere in which the structure is disposed to introduce the gas whose pressure is to be measured. as well as The inner chamber, via the inlet tube, is set to the pressure being measured. The two diaphragms are configured as part of the partition walls of the inner chamber, comprising two opposing surfaces and two non-opposing surfaces. In the pressure measurement method described above, The pressure to be measured is applied to the two opposing surfaces. The reference vacuum is applied to the two non-opposing surfaces. The two diaphragms are displaced according to the pressure difference between the measured pressure and the reference vacuum, and the absolute values ​​of the displacements of the two diaphragms are equal and opposite to each other.

13. The pressure measurement method according to claim 12, wherein, The inner chamber includes: The first chamber is set to the pressure to be measured via the inlet tube; The second chamber communicates with the interior of the outer structure and is airtightly isolated from the first chamber; and A bellows, which divides the first chamber and the second chamber and is connected to the two diaphragms, is deformable to allow displacement of the two diaphragms. The opposing surfaces of the two diaphragms are arranged facing the interior of the first chamber. The detection element is disposed in the second chamber.

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