JPH02269928A - Vacuum gauge - Google Patents

Vacuum gauge

Info

Publication number
JPH02269928A
JPH02269928A JP9238789A JP9238789A JPH02269928A JP H02269928 A JPH02269928 A JP H02269928A JP 9238789 A JP9238789 A JP 9238789A JP 9238789 A JP9238789 A JP 9238789A JP H02269928 A JPH02269928 A JP H02269928A
Authority
JP
Japan
Prior art keywords
vibrating beam
vibration
vacuum
natural frequency
degree
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP9238789A
Other languages
Japanese (ja)
Inventor
Kinji Harada
原田 謹爾
Kyoichi Ikeda
恭一 池田
Hideki Kuwayama
桑山 秀樹
Takashi Kobayashi
隆 小林
Tetsuya Watanabe
哲也 渡辺
Sunao Nishikawa
直 西川
Takashi Yoshida
隆司 吉田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yokogawa Electric Corp
Original Assignee
Yokogawa Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yokogawa Electric Corp filed Critical Yokogawa Electric Corp
Priority to JP9238789A priority Critical patent/JPH02269928A/en
Publication of JPH02269928A publication Critical patent/JPH02269928A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE:To reduce the noises of an instrument and to improve the measurement accuracy by allowing a vibration beam to oscillate itself at its natural vibration frequency in a nonlinear vibration area. CONSTITUTION:The vibration beam 2 is made to vibrate itself at its natural vibration frequency in the nonlinear vibration area. Namely, the vibration beam 2 is in motion in a magnetic field, so a conductor crosses magnetic flux to generate an electromotive force. This electromotive force is amplified by an amplifier 3 and the vibration beam 2 oscillates. Then a counter 5 counts the natural vibration frequency of the vibration beam 2. Then a CPU 7 calculates the degree of vacuum from the natural vibration frequency of the vibration beam 2 from the output of the counter 5 and calibration data from a ROM 6. Then a display mechanism 8 displays the degree of vacuum according to the output of the CPU 7. Consequently, noises of the instrument are reduced to improve the accuracy.

Description

【発明の詳細な説明】 〈産業上の利用分野〉 本発明は、ノイズに強く、精度が良好な真空計に関する
ものである。
DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a vacuum gauge that is resistant to noise and has good accuracy.

〈従来の技術〉 従来、振動式真空計としては、例えば、水晶振動式真空
計がある。
<Prior Art> Conventionally, as a vibrating vacuum gauge, for example, there is a crystal vibrating vacuum gauge.

水晶振動式真空計では、真空度が上がると振動振幅が大
きくなることを利用し、振動振幅を電圧信号として真空
度を測定している。
A crystal vibration vacuum gauge uses the fact that the vibration amplitude increases as the degree of vacuum increases, and uses the vibration amplitude as a voltage signal to measure the degree of vacuum.

〈発明が解決しようとする課題〉 しかしながら、この様な装置においては、真空度が低い
、即ち、振幅が小さい領域では、出力電圧が小さく、増
幅等すると、アナログ信号なので、ノイズを拾いやすく
、誤差を生じやすく、測定精度を上げる事が雌しい。
<Problem to be solved by the invention> However, in such a device, in a region where the degree of vacuum is low, that is, the amplitude is small, the output voltage is small, and when amplified etc., it is an analog signal, so it is easy to pick up noise and cause errors. It is important to improve measurement accuracy.

本発明は、この問題点を解決するものである。The present invention solves this problem.

本発明の目的は、ノイズに強く、精度が良好な真空計を
提供するにある。
An object of the present invention is to provide a vacuum gauge that is resistant to noise and has good accuracy.

く課題を解決するための手段〉 この目的を達成するために、本発明は、基板に支持され
た振動梁と、該振動梁を非線形振動領域で該振動梁の固
有振動数で自励発振させる自励発振回路と、前記振動梁
の固有振動数をカウントするカウンタと、線形領域での
固有振動数に対する測定固有振動数のずれ量から真空度
を演算検出する演算回路とを具備してなる真空計を構成
したものである。
Means for Solving the Problems> To achieve this object, the present invention provides a vibrating beam supported by a substrate, and a method of self-oscillating the vibrating beam at its natural frequency in a nonlinear vibration region. A vacuum comprising a self-excited oscillation circuit, a counter that counts the natural frequency of the vibrating beam, and an arithmetic circuit that calculates and detects the degree of vacuum from the deviation amount of the measured natural frequency from the natural frequency in the linear region. It consists of a meter.

く作 用〉 以上の構成において、振動梁を非線形振動領域で振動梁
の固有振動数で自励発振させる。このときの振動梁の固
有振動数をカウンタでカウントする。cpuにおいてカ
ウンタの出力とROMの校正データとを基にして、振動
梁の固有振動数から真空度を演算する0表示機構でCP
Uの出力から真空度を表示あるいは記録する。
In the above configuration, the vibrating beam is caused to self-oscillate at its natural frequency in the nonlinear vibration region. The natural frequency of the vibrating beam at this time is counted by a counter. The CPU uses a zero display mechanism that calculates the degree of vacuum from the natural frequency of the vibrating beam based on the output of the counter and the calibration data in the ROM.
Display or record the degree of vacuum from the output of U.

以下、実施例に基づき詳細に説明する。Hereinafter, a detailed explanation will be given based on examples.

〈実施例〉 第1図は本発明の一実施例のブロック説明図である。<Example> FIG. 1 is a block diagram illustrating an embodiment of the present invention.

図において、1は交流信号を一定電圧にクリップするリ
ミッタ−である、 13’lJえば、ツェナーダイオー
ドを使用した回路が用いられる。
In the figure, 1 is a limiter that clips the AC signal to a constant voltage. 13'lJ is a circuit using a Zener diode.

2は振動梁で、後に詳述する。2 is a vibrating beam, which will be explained in detail later.

3はアン1で、リミッタ1と振動梁2と共に後に詳述す
る如く、自励振回路4が構成される。
Reference numeral 3 denotes an amplifier 1, which together with the limiter 1 and the vibrating beam 2 constitutes a self-oscillation circuit 4 as will be described in detail later.

5は振動梁2の固有振動数をカウントするカウンタであ
る。
5 is a counter that counts the natural frequency of the vibrating beam 2.

6は線形領域での固有振動数foに対する測定固有振動
数fのずれ(f  fo)に対して予め測定決定された
校正データが記憶されたROMである。
Reference numeral 6 denotes a ROM in which calibration data previously measured and determined for the deviation (f fo ) of the measured natural frequency f with respect to the natural frequency fo in the linear region is stored.

7はカウンタ5の出力とROM6の校正データとを基に
して振動梁の固有振動数から真空度を演算するcpuで
ある。
7 is a CPU that calculates the degree of vacuum from the natural frequency of the vibrating beam based on the output of the counter 5 and the calibration data of the ROM 6.

8はCPU7の出力から真空度を表示あるいは記録する
表示機構である。
8 is a display mechanism that displays or records the degree of vacuum from the output of the CPU 7.

第2図に自励振回路4の具体例の要部構成説明図を示す
FIG. 2 shows an explanatory diagram of the main part configuration of a specific example of the self-oscillation circuit 4.

第3図は第2図のA−A断面図、第4図(A>、(B)
は第2図を電気回路で示した図であり、第4図(B)は
p形層とn+形層の間に逆バイアス電圧を印加するため
の電源を示している。
Figure 3 is a sectional view taken along line AA in Figure 2, Figure 4 (A>, (B))
2 is an electrical circuit diagram of FIG. 2, and FIG. 4(B) shows a power source for applying a reverse bias voltage between the p-type layer and the n+-type layer.

これらの図において、11は+100+面を有する、例
えば不純物濃度1015原子/ c m 3以下のp形
のシリコン基板である。このシリコン基板11の表面(
エツチングしない面)には部分的に不純物濃度10′7
程度のn十拡f!1層(図では省略)が形成され、この
n十拡散層の一部に振動梁2が<001>方向に形成さ
れている。なお、この振動梁2は基板11に形成された
n十層および2層をフォトリングラフィとアンダエッチ
ングの技術を用いて加工する。
In these figures, 11 is a p-type silicon substrate having a +100+ plane and having an impurity concentration of, for example, 1015 atoms/cm 3 or less. The surface of this silicon substrate 11 (
The impurity concentration is 10'7 partially on the non-etched surface.
About n ten expansion f! One layer (omitted from the figure) is formed, and a vibrating beam 2 is formed in a part of this n10 diffusion layer in the <001> direction. Note that this vibrating beam 2 is fabricated by processing the n10 layers and two layers formed on the substrate 11 using photolithography and under-etching techniques.

13は振動梁2の略中央上部に振動梁2に直交し、かつ
、非接触の状態で設けられた磁石、14は絶縁膜として
のS i 02膜(第3図参照°)である、15a、1
5bは例えばAIなどの金属電極で、この金属電極15
aの一端は振動梁2〃)ら延長したn十層に5i02層
に設けたコンタクトホール16a、を通じて接続され、
他端はリード線を介して振動梁2の抵抗値とほぼ等しい
比較抵抗R0および増幅器17の一端に接続されている
13 is a magnet provided approximately at the upper center of the vibrating beam 2 so as to be orthogonal to the vibrating beam 2 and in a non-contact state; 14 is an S i 02 film as an insulating film (see FIG. 3); 15a; ,1
5b is a metal electrode such as AI, and this metal electrode 15
One end of a is connected to the n10 layer extending from the vibrating beam 2) through a contact hole 16a provided in the 5i02 layer,
The other end is connected to one end of the amplifier 17 and a comparison resistor R0 whose resistance value is approximately equal to the resistance value of the vibrating beam 2 via a lead wire.

増幅器17の出力は出力信号として取出されるとともに
分岐して一次コイルL1の一端に接続されている。この
コイルし、の他端はコモンラインに接続されている。
The output of the amplifier 17 is taken out as an output signal, branched off, and connected to one end of the primary coil L1. The other end of this coil is connected to the common line.

一方比教抵抗ROの他端は中点がコモンラインに接続し
た2次コイルL2の他端に接続され、この2次コイルL
2のIf!!端は振動梁2の他端に前記同様に形成され
た金属な極L5bに接続されている。
On the other hand, the other end of the religious resistance RO is connected to the other end of the secondary coil L2 whose middle point is connected to the common line.
2 If! ! The end is connected to the metal pole L5b formed in the same manner as described above at the other end of the vibrating beam 2.

上記構成において、ρ形層(基板11〉とn+形層(振
動梁2)の間に逆バイアス電圧を印加して絶縁し、振動
梁2に交流電流iを流すと振動梁2の共振周波数におい
て電磁誘導作用により振動梁の、インピーダンスが上昇
して、比較抵抗R0、および中点をコモンラインに接続
したL2により構成されるブリッジにより不平衡信号を
得ることができる。この信号を増幅器17で増幅し、コ
イルL1に正帰還すると、系は振動梁2の固有振動数で
自励発振する。
In the above configuration, when a reverse bias voltage is applied between the ρ type layer (substrate 11) and the n+ type layer (vibrating beam 2) to insulate them, and an alternating current i is passed through the vibrating beam 2, the resonant frequency of the vibrating beam 2 The impedance of the vibrating beam increases due to electromagnetic induction, and an unbalanced signal can be obtained by the bridge formed by the comparison resistor R0 and L2 whose midpoint is connected to the common line.This signal is amplified by the amplifier 17. However, when positive feedback is given to the coil L1, the system self-oscillates at the natural frequency of the vibrating beam 2.

以上の構成において、振動梁2を非線形振動領域で振動
梁2の固有振動数で自励発振させる。このときの振動梁
2の固有振動数をカウンタ5でカウントする。CPU7
においてカウンタ5の出力とROM60校正データとを
基にして、振動梁2の固有振動数から真空度を演算する
6表示m構8でCPU7の出力から真空度を表示あるい
は記録する。
In the above configuration, the vibrating beam 2 is caused to self-oscillate at the natural frequency of the vibrating beam 2 in a nonlinear vibration region. A counter 5 counts the natural frequency of the vibrating beam 2 at this time. CPU7
The degree of vacuum is displayed or recorded from the output of the CPU 7 in a 6-display m system 8 which calculates the degree of vacuum from the natural frequency of the vibrating beam 2 based on the output of the counter 5 and the calibration data of the ROM 60.

而して、振動梁2は磁場中で運動することになる為、導
体が磁束を切ることによって生じるき起電力eが発生す
る。この起電力eをアンプで増幅し、振動梁2は発振し
、またその出力の大きさは、Q値に比例するなめ真空度
を計ることができる。
Since the vibrating beam 2 moves in the magnetic field, an electromotive force e is generated when the conductor cuts the magnetic flux. This electromotive force e is amplified by an amplifier to cause the vibrating beam 2 to oscillate, and the magnitude of the output can be used to measure the degree of vacuum, which is proportional to the Q value.

真空度とQ値との関係を第5図に示す。FIG. 5 shows the relationship between the degree of vacuum and the Q value.

ここで、振動梁2を自励振させドライブパワーを一定に
保って置くと、真空度が上がるにつれて、振動梁と衝突
する気体分子数か減少し、この事による振動梁のエネル
ギーロスは小さくなるため、振動振幅aは真空度に比例
して大きくなる。非線形振動領域では、振幅が大きくな
るとハードスプリング効果によって、共振周波数fが下
記の関係式に従ってずれる。。
Here, if the vibrating beam 2 is made to self-oscillate and the drive power is kept constant, as the degree of vacuum increases, the number of gas molecules colliding with the vibrating beam will decrease, and the energy loss of the vibrating beam due to this will become smaller. , the vibration amplitude a increases in proportion to the degree of vacuum. In the nonlinear vibration region, when the amplitude becomes large, the resonant frequency f shifts according to the following relational expression due to the hard spring effect. .

Ka’ = (f/fo )21      (1)K
:非線形定数 a:振幅 f:測定周波数 fO:線形領域での固有振動数 a−α/p                    
 (2)α : p:真空度 (1)(2)式より にα’ / p ’ −(f / f o ) 21p
  −[((f/fo  )  2  1 1  /K
  α 2 コ I/2この結果、振動の非線形領域で
振動梁2を振動させたので、 (1)ハードスプリング効果によって、固有振動数が第
6図に示す如く、振幅により変化する。
Ka' = (f/fo)21 (1)K
: Nonlinear constant a: Amplitude f: Measurement frequency fO: Natural frequency a-α/p in linear region
(2) α: p: Degree of vacuum From equations (1) and (2), α'/p' - (f/fo) 21p
−[((f/fo) 2 1 1 /K
α 2 ko I/2 As a result, since the vibrating beam 2 was vibrated in the nonlinear region of vibration, (1) Due to the hard spring effect, the natural frequency changes with the amplitude as shown in FIG.

また、第7図に示す如く、固有振動数fのシフ1〜量は
振幅aに直線比例する。
Further, as shown in FIG. 7, the shift amount of the natural frequency f is linearly proportional to the amplitude a.

この事は、(1)式において、(f −f o / f
。)くく1として近似させた場合に、 a= [(2/ (Kfo )) ・(f−fo)]+12 となることと良く一致する。
This means that in equation (1), (f − f o / f
. ) When approximated as 1, it agrees well with a=[(2/(Kfo))・(f−fo)]+12.

このなめ、従来は信号電圧を増幅して出力していたが、
これを周波数出力とする事ができ、ノイズに強く、精度
が良いものが得られる。
Conventionally, the signal voltage was amplified and outputted, but
This can be used as a frequency output, making it resistant to noise and highly accurate.

(2)ドライブレベルが大きくでき、従って、出力信号
も大きいので、S/N比が良好なものが得られる。
(2) Since the drive level can be increased and the output signal is also large, a good S/N ratio can be obtained.

なお、前述の実施例においては、振動梁2は磁場内で振
動するものについて説明したが、これに限ることはなく
、要するに、自動振動し振動振幅が検出できるものであ
れば良い。
In the above-mentioned embodiment, the vibrating beam 2 was described as one that vibrates within a magnetic field, but the present invention is not limited to this, and in short, any vibrating beam 2 may be used as long as it vibrates automatically and the vibration amplitude can be detected.

〈発明の効果〉 以上説明したように、本発明は、基板に支持された振動
梁と、該振動梁を非線形振動領域で該振動梁の固有振動
数で自励発振させる自励発振回路と、前記振動梁の固有
振動数をカウントするカウンタと、線形領域での固有振
動数に対する測定固有振動数のずれ量から真空度を演算
検出する演算回路とを具備してなる真空計を構成した。
<Effects of the Invention> As explained above, the present invention includes a vibrating beam supported by a substrate, a self-excited oscillation circuit that causes the vibrating beam to self-oscillate at the natural frequency of the vibrating beam in a nonlinear vibration region, A vacuum gauge was constructed that includes a counter that counts the natural frequency of the vibrating beam, and an arithmetic circuit that calculates and detects the degree of vacuum from the deviation amount of the measured natural frequency with respect to the natural frequency in the linear region.

この結果、振動の非線形領域で振動梁を振動させなので
、 (1)ハードスプリング効果によって、固有振動数が振
幅に対応して変化する。
As a result, since the vibrating beam is vibrated in a nonlinear region of vibration, (1) the natural frequency changes in accordance with the amplitude due to the hard spring effect.

また、固有振動数fのシフト量は振幅aに直線比例する
Further, the amount of shift of the natural frequency f is linearly proportional to the amplitude a.

このなめ、従来は信号電圧を増幅して出力していたが、
これを周波数出力とする事ができ、ノイズに強く、精度
が良いものが得られる。
Conventionally, the signal voltage was amplified and outputted, but
This can be used as a frequency output, making it resistant to noise and highly accurate.

(2)ドライブレベルが大きくでき、従って、出力信号
も大きいので、S/N比が良好なものが得られる。
(2) Since the drive level can be increased and the output signal is also large, a good S/N ratio can be obtained.

従って、本発明によれば、ノイズに強く、精度が良好な
真空計を゛実現することが出来る。
Therefore, according to the present invention, it is possible to realize a vacuum gauge that is resistant to noise and has good accuracy.

【図面の簡単な説明】[Brief explanation of drawings]

第1図は本発明の一実施例の要部構成説明図、第2図は
第1図の振動梁2の要部構成説明図、第3図は第2図の
A−A断面図、第4図(A)、<B)は第2図を電気回
路で示した図であり、第4図(B)はp形層とn十形層
の間に逆バイアス電圧を印加するための電源を示す、第
5図、第6図、第7図は第2図の動作説明図である。 1・・・リミッタ、2・・・振動梁、3・・・アンプ、
4・・・自動心回路、5・・・カウンタ、6・・・RO
M、7・・・CPU、8− 表示ts槽、11−・・基
板、13 ニー、磁石、14・・・酸化シリコン膜、1
5a、1.5b・・・電極、16a、16b・・・コン
タク1〜ホール、17・・・増幅器。 第2図 第3図 →Q  Value 第7図 Δす →丼」酊司波数のシフト了1 手続補正書(方式) 1、事件の表示    特願平1−92387号2、発
明の名称    真空計 3、補正する者 一件との関係   特許出願人 住 所     東京都武蔵野市中町2丁目9番32号
名 称    横河電機株式会社 埋入 住 所     東京都武蔵野市中町2丁目9番32号
ノ、Tm正命令の日付(発送日) 6、補 7、補 ^             −1 〜                ・\=1 ヘ         −ρ
FIG. 1 is an explanatory diagram of the main part of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the main part of the vibrating beam 2 shown in FIG. 1, and FIG. Figures 4 (A) and <B) are electrical circuit diagrams of Figure 2, and Figure 4 (B) is a power supply for applying a reverse bias voltage between the p-type layer and the n-type layer. 5, 6, and 7 are explanatory diagrams of the operation of FIG. 2. 1...Limiter, 2...Vibration beam, 3...Amplifier,
4...Automatic heart circuit, 5...Counter, 6...RO
M, 7... CPU, 8- Display TS tank, 11-... Substrate, 13 Knee, magnet, 14... Silicon oxide film, 1
5a, 1.5b...electrode, 16a, 16b...contact 1 to hole, 17...amplifier. Figure 2 Figure 3 → Q Value Figure 7 ΔS → Bowl” Shift of Keiji wave number completed 1 Procedural amendment (method) 1. Indication of the incident Patent Application No. 1-92387 2. Title of the invention Vacuum gauge 3 , Relationship with the person making the amendment Patent applicant Address: 2-9-32 Nakamachi, Musashino-shi, Tokyo Name: Yokogawa Electric Corporation Address: Tm Masashi, 2-9-32 Nakamachi, Musashino-shi, Tokyo Order date (shipment date) 6, Supplement 7, Supplement ^ -1 ~ ・\=1 F -ρ

Claims (1)

【特許請求の範囲】 基板に支持された振動梁と、 該振動梁を非線形振動領域で該振動梁の固有振動数で自
励発振させる自励発振回路と、 前記振動梁の固有振動数をカウントするカウンタと、 線形領域での固有振動数に対する測定固有振動数のずれ
量から真空度を演算検出する演算回路とを具備してなる
真空計。
[Scope of Claims] A vibrating beam supported by a substrate; a self-excited oscillation circuit that causes the vibrating beam to self-oscillate at a natural frequency of the vibrating beam in a nonlinear vibration region; and counting the natural frequency of the vibrating beam. 1. A vacuum gauge comprising: a counter that calculates the degree of vacuum; and an arithmetic circuit that calculates and detects the degree of vacuum from the deviation of the measured natural frequency from the natural frequency in the linear region.
JP9238789A 1989-04-12 1989-04-12 Vacuum gauge Pending JPH02269928A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9238789A JPH02269928A (en) 1989-04-12 1989-04-12 Vacuum gauge

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9238789A JPH02269928A (en) 1989-04-12 1989-04-12 Vacuum gauge

Publications (1)

Publication Number Publication Date
JPH02269928A true JPH02269928A (en) 1990-11-05

Family

ID=14053012

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9238789A Pending JPH02269928A (en) 1989-04-12 1989-04-12 Vacuum gauge

Country Status (1)

Country Link
JP (1) JPH02269928A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5856820A (en) * 1981-09-30 1983-04-04 Matsushita Electric Works Ltd Embossing method
JPS62288542A (en) * 1986-06-06 1987-12-15 Yokogawa Electric Corp Vibration type semiconductor transducer
JPS63171335A (en) * 1987-01-09 1988-07-15 Daiwa Shinku Kogyosho:Kk Temperature compensating system for piezoelectric type pressure gage
JPS646837A (en) * 1987-06-30 1989-01-11 Yokogawa Electric Corp Vibration type differential pressure sensor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5856820A (en) * 1981-09-30 1983-04-04 Matsushita Electric Works Ltd Embossing method
JPS62288542A (en) * 1986-06-06 1987-12-15 Yokogawa Electric Corp Vibration type semiconductor transducer
JPS63171335A (en) * 1987-01-09 1988-07-15 Daiwa Shinku Kogyosho:Kk Temperature compensating system for piezoelectric type pressure gage
JPS646837A (en) * 1987-06-30 1989-01-11 Yokogawa Electric Corp Vibration type differential pressure sensor

Similar Documents

Publication Publication Date Title
JP3223358B2 (en) Resonant gauge by microbeam driven by constant electric field
US6820469B1 (en) Microfabricated teeter-totter resonator
JP2006030195A (en) Magnetometer having electromechanical resonator
JPH01299428A (en) Vibration-type transducer and manufacture thereof
US7429858B2 (en) Oscillating-beam magnetometer
US10126376B1 (en) Quartz magnetometer having a quartz resonant plate with a broaden distal end for enhanced magnetic sensitivity
US4680544A (en) Torsion type magnetic field measurement device
Donzier et al. Integrated magnetic field sensor
US20020104689A1 (en) Electronic weighing apparatus utilizing surface acoustic waves
WO2004070408A1 (en) Magnetic sensor
JPH02269928A (en) Vacuum gauge
Greywall Sensitive magnetometer incorporating a high-Q nonlinear mechanical resonator
US4916821A (en) Electronic compass and other magnetic devices
JPH01145539A (en) Vibration type semiconductor temperature sensor
JPH0628662Y2 (en) Vibration type differential pressure sensor
JPH01114730A (en) Vibration type semiconductor transducer
JPH0468576B2 (en)
JPH0238934A (en) Vibration type semiconductor transducer
JP2618729B2 (en) Micro weight change measuring device
JPS58174809A (en) Azimuth sensor
JPH10328152A (en) Electromagnetic rheometer
JPH0467899B2 (en)
JPH02232538A (en) Vibration type semiconductor transducer
JPH0431728A (en) Semiconductor pressure gage
JP2000065908A (en) Magnetic sensor and magnetic detection system