JP2003322658A - Flow velocity sensor - Google Patents
Flow velocity sensorInfo
- Publication number
- JP2003322658A JP2003322658A JP2002130507A JP2002130507A JP2003322658A JP 2003322658 A JP2003322658 A JP 2003322658A JP 2002130507 A JP2002130507 A JP 2002130507A JP 2002130507 A JP2002130507 A JP 2002130507A JP 2003322658 A JP2003322658 A JP 2003322658A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- flow velocity
- temperature measuring
- measuring resistance
- resistance
- 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.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
- G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
- G01F1/688—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element
- G01F1/69—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element of resistive type
- G01F1/692—Thin-film arrangements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
- G01F1/696—Circuits therefor, e.g. constant-current flow meters
- G01F1/698—Feedback or rebalancing circuits, e.g. self heated constant temperature flowmeters
- G01F1/699—Feedback or rebalancing circuits, e.g. self heated constant temperature flowmeters by control of a separate heating or cooling element
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/10—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring thermal variables
- G01P5/12—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring thermal variables using variation of resistance of a heated conductor
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Measuring Volume Flow (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、気体や液体等の流
体の流速測定に用いられる流速センサに関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow velocity sensor used for measuring the flow velocity of a fluid such as gas or liquid.
【０００２】[0002]
【従来の技術】出願人は、特開平２−２５９５２７号公
報で、高精度かつ高速応答を実現する半導体微細加工構
成の流速センサを提案した。図１は本発明の代表的な流
速センサの平面図及び断面図であるが、従来の流速セン
サもその基本構成は同様であるので、図１を用いて特開
平２−２５９５２７号公報の流速センサの構成を説明す
る。2. Description of the Related Art The applicant proposed in Japanese Patent Application Laid-Open No. 2-259527 a flow velocity sensor having a semiconductor microfabrication structure which realizes high precision and high speed response. FIG. 1 is a plan view and a cross-sectional view of a typical flow velocity sensor of the present invention. Since the conventional flow velocity sensor has the same basic structure, the flow velocity sensor disclosed in JP-A-2-259527 will be described with reference to FIG. The configuration of will be described.
【０００３】流速センサは、単結晶シリコンなどからな
る基台１上に形成され、この基台１の中央部には空隙部
２が形成されている。また、基台１上には、空隙部２に
よって基台１から空間的に隔離された薄膜層３が形成さ
れている。薄膜層３には、空隙部２を介して連通する対
をなすスリット４ａ，４ｂが互いに所定の間隔をおいて
設けられている。さらに、これらのスリット４ａ，４ｂ
の間には、スリット４ａ，４ｂの間を結ぶ直線と直交す
る方向に延びるスリット５が設けられており、このスリ
ット５により、スリット４ａ，４ｂの間に２つの配設部
６ａ，６ｂが形成されている。配設部６ａ，６ｂは、ス
リット５により互いに熱的に絶縁されている。The flow velocity sensor is formed on a base 1 made of single crystal silicon or the like, and a void 2 is formed in the center of the base 1. Further, on the base 1, a thin film layer 3 is formed which is spatially separated from the base 1 by a void 2. The thin film layer 3 is provided with a pair of slits 4a and 4b which communicate with each other via the void portion 2 at a predetermined interval. Furthermore, these slits 4a, 4b
Between them, a slit 5 extending in a direction orthogonal to a straight line connecting the slits 4a and 4b is provided, and the slit 5 forms two disposing portions 6a and 6b between the slits 4a and 4b. Has been done. The arrangement portions 6a and 6b are thermally insulated from each other by the slit 5.
【０００４】配設部６ａには、発熱体兼温度センサとし
て機能する測温抵抗エレメントＡが形成され、同様に、
配設部６ｂには、発熱体兼温度センサとして機能する測
温抵抗エレメントＢが形成されている。また、薄膜層３
と基台１とが熱的に接する部分、すなわち空隙部２が設
けられていない部分には、周囲温度により抵抗値が変化
する周囲温度測温抵抗エレメントＣが形成されている。A temperature measuring resistance element A which functions as a heating element and a temperature sensor is formed in the disposing portion 6a.
A temperature measuring resistance element B, which functions as a heating element and a temperature sensor, is formed in the arrangement portion 6b. Also, the thin film layer 3
At a portion where the base 1 and the base 1 are in thermal contact with each other, that is, a portion where the void 2 is not provided, an ambient temperature temperature measuring resistance element C whose resistance value changes according to the ambient temperature is formed.
【０００５】図６は特開平２−２５９５２７号公報で提
案した流速センサの電気回路図である。流速センサの電
気回路は、基台１上を移動する気体の流速を測定するた
めのものであり、温度差検出回路１００と、定電流回路
２００と、スイッチング回路３００とで構成されてい
る。温度差検出回路１００は、測温抵抗エレメントＡ，
Ｂとそれより大きな抵抗値を持つ抵抗Ｒ１０１，Ｒ１０
２とで構成されるブリッジ回路と、このブリッジ回路の
出力電圧を増幅する増幅器Ａ１０１，Ａ１０２と、この
増幅器Ａ１０１，Ａ１０２の出力電圧の差分値を出力す
る差分増幅器Ａ１０３とで構成されている。ブリッジ回
路は、周囲温度測温抵抗エレメントＣとトランジスタＴ
Ｒ２０１，ＴＲ２０２と抵抗Ｒ２０１で構成される定電
流回路２００から定電流を供給されるとともに、トラン
ジスタＴＲ３０１と抵抗Ｒ３０１とで構成されるスイッ
チング回路３００により間欠的に駆動されることにな
る。FIG. 6 is an electric circuit diagram of a flow velocity sensor proposed in Japanese Patent Laid-Open No. 2-259527. The electric circuit of the flow velocity sensor is for measuring the flow velocity of the gas moving on the base 1, and is composed of a temperature difference detection circuit 100, a constant current circuit 200, and a switching circuit 300. The temperature difference detection circuit 100 includes a temperature measuring resistance element A,
B and resistors R101 and R10 having a larger resistance value
2 includes a bridge circuit, amplifiers A101 and A102 for amplifying the output voltage of the bridge circuit, and a difference amplifier A103 for outputting a difference value of the output voltages of the amplifiers A101 and A102. The bridge circuit includes an ambient temperature measuring resistance element C and a transistor T.
A constant current is supplied from a constant current circuit 200 composed of R201 and TR202 and a resistor R201, and is driven intermittently by a switching circuit 300 composed of a transistor TR301 and a resistor R301.
【０００６】ここで、周囲温度測温抵抗エレメントＣ
は、周囲温度の変化を補償するために設けられている。
測温抵抗エレメントＡ，Ｂは、定電流回路２００から供
給される定電流によって発熱する。ここで、抵抗Ｒ１０
１，Ｒ１０２は、測温抵抗エレメントＡ，Ｂに比べてか
なり大きな抵抗値を有することから、測温抵抗エレメン
トＡ，Ｂは一定電流で駆動されるものと見なすことがで
きる。Here, the ambient temperature measuring resistance element C
Are provided to compensate for changes in ambient temperature.
The temperature measuring resistance elements A and B generate heat by the constant current supplied from the constant current circuit 200. Here, the resistor R10
Since 1 and R 102 have resistance values considerably larger than those of the temperature measuring resistance elements A and B, it can be considered that the temperature measuring resistance elements A and B are driven by a constant current.
【０００７】流速センサの表面で気体が流れると、その
上流側に位置する測温抵抗エレメントＡは、その下流側
に位置する測温抵抗エレメントＢに比べて、より強く冷
やされる。これにより、２つの測温抵抗エレメントＡ，
Ｂ間に温度差が現れ、この温度差は抵抗変化となり、前
記ブリッジ回路はその平衡を失って、差分増幅器Ａ１０
３はその温度差に応じた電圧を出力する。When the gas flows on the surface of the flow velocity sensor, the temperature measuring resistance element A located upstream thereof is cooled more strongly than the temperature measuring resistance element B located downstream thereof. As a result, the two temperature measuring resistance elements A,
A temperature difference appears between B and this temperature difference causes a resistance change, the bridge circuit loses its balance, and the difference amplifier A10
3 outputs a voltage according to the temperature difference.
【０００８】[0008]
【発明が解決しようとする課題】特開平２−２５９５２
７号公報で提案した流速センサは、測温抵抗エレメント
Ａ，Ｂを熱絶縁した薄膜層３上に形成していることか
ら、流体の流速を高精度に検出できるという特徴を有し
ている。しかしながら、この流速センサでは、流速が増
加すると、下流側の測温抵抗エレメントＢから奪われる
熱エネルギーが増大して温度が低下し、上流側と下流側
の測温抵抗エレメントＡ，Ｂの抵抗値の差が減少する。
このため、特開平２−２５９５２７号公報で提案した流
速センサでは、流速が増加すると、感度が低下し、高流
速における測定が困難になるという問題点があった。ま
た、この流速センサでは、測温抵抗エレメントＡ，Ｂを
定電流駆動しているため、流速によって測温抵抗エレメ
ントＡ，Ｂおよびその近傍の薄膜層３の平均温度が変化
する。つまり、測温抵抗エレメントＡ，Ｂの直列抵抗が
変化する。この温度、つまり測温抵抗エレメントＡ，Ｂ
の直列抵抗が変化すると、測温抵抗エレメントＡ，Ｂお
よびその近傍の薄膜層３が持つ熱容量のための熱的遅れ
とともに測温抵抗エレメントＡ，Ｂでの発熱量変化によ
る温度変化がこれと干渉することによる遅れが生じ、結
果として応答速度が遅くなるという問題点があった。本
発明は、上記課題を解決するためになされたもので、広
範囲な流速を測定することができる高速応答の流速セン
サを提供することを目的とする。[Patent Document 1] Japanese Patent Laid-Open No. 25952/1990
The flow velocity sensor proposed in Japanese Patent Publication No. 7 has a feature that the flow velocity of the fluid can be detected with high accuracy because the temperature measuring resistance elements A and B are formed on the thermally insulated thin film layer 3. However, in this flow velocity sensor, when the flow velocity increases, the thermal energy taken from the temperature measuring resistance element B on the downstream side increases and the temperature decreases, and the resistance values of the temperature measuring resistance elements A and B on the upstream side and the downstream side decrease. The difference between is reduced.
Therefore, the flow velocity sensor proposed in Japanese Patent Application Laid-Open No. 2-259527 has a problem that when the flow velocity increases, the sensitivity decreases and measurement at high flow velocity becomes difficult. Further, in this flow velocity sensor, since the temperature measuring resistance elements A and B are driven with a constant current, the average temperature of the temperature measuring resistance elements A and B and the thin film layer 3 in the vicinity thereof changes. That is, the series resistance of the temperature measuring resistance elements A and B changes. This temperature, that is, the temperature measuring resistance elements A and B
If the series resistance of the temperature-measuring resistance elements A and B and the thin film layer 3 in the vicinity of the temperature-measuring resistance elements A and B is delayed, the temperature change due to the change in the calorific value of the temperature-measuring resistance elements A and B interferes with this. However, there is a problem that a delay occurs due to this, and as a result, the response speed becomes slow. The present invention has been made to solve the above problems, and an object of the present invention is to provide a high-speed response flow velocity sensor capable of measuring a wide range of flow velocity.
【０００９】[0009]
【課題を解決するための手段】本発明は、流体の流れ方
向に並べて配置された発熱体と温度センサとにより、そ
の流体の流れに起因する熱移動を求めることによって流
体の流速を測定する流速センサにおいて、前記発熱体お
よび温度センサを共用する第１の測温抵抗エレメントお
よび第２の測温抵抗エレメントを直列に接続し、この第
１および第２の測温抵抗エレメントに流される電流をそ
れらの平均温度が周囲温度より常に一定温度だけ高くな
るように制御する制御回路を有し、前記第１および第２
の測温抵抗エレメントの温度差に基づいて流速を求める
ようにしたものである。また、本発明の流速センサは、
前記温度センサである第１の測温抵抗エレメントおよび
第２の測温抵抗エレメントを直列に接続すると共に、こ
れら各測温抵抗エレメントのそれぞれの近傍に前記発熱
体を配置し、前記第１および第２の測温抵抗エレメント
の平均温度が周囲温度より常に一定温度だけ高くなるよ
うに前記発熱体への電流を制御する制御回路を有し、前
記第１および第２の測温抵抗エレメントの温度差に基づ
いて流速を求めるようにしたものである。SUMMARY OF THE INVENTION According to the present invention, a flow velocity for measuring the flow velocity of a fluid is obtained by determining heat transfer due to the flow of the fluid by a heating element and a temperature sensor which are arranged side by side in the flow direction of the fluid. In the sensor, a first resistance temperature element and a second resistance temperature element, which share the heating element and the temperature sensor, are connected in series, and the currents flowing through the first resistance resistance element and the second resistance temperature element are connected to each other. Has a control circuit for controlling so that the average temperature of the above is always higher than the ambient temperature by a constant temperature.
The flow velocity is obtained based on the temperature difference between the temperature measuring resistance elements. Further, the flow velocity sensor of the present invention,
The first temperature measuring resistance element and the second temperature measuring resistance element, which are the temperature sensors, are connected in series, and the heating element is arranged in the vicinity of each of the temperature measuring resistance elements. A temperature difference between the first and second temperature measuring resistance elements, the control circuit controlling the current to the heating element so that the average temperature of the second temperature measuring resistance element is always higher than the ambient temperature by a constant temperature. The flow velocity is calculated based on
【００１０】また、本発明の流速センサの１構成例は、
前記直列に接続された第１および第２の測温抵抗エレメ
ントとを一辺とするブリッジ回路を構成し、この一辺以
外の他の一辺に流体の流れに影響されない周囲温度を測
定する周囲温度センサを含ませ、前記ブリッジ回路の各
中点の電圧差を一定にするように前記発熱体に流す電流
を制御する差動増幅回路を設けたものである。また、本
発明の流速センサの１構成例は、前記直列に接続された
第１および第２の測温抵抗エレメントの両端電圧を少な
くとも１つのボルテージフォロア回路で受け、前記両端
電圧の分圧と前記第１および第２の測温抵抗エレメント
の接続点の電圧とを比較して流速を求めるようにしたも
のである。Further, one configuration example of the flow velocity sensor of the present invention is as follows:
A bridge circuit having one side of the first and second temperature measuring resistance elements connected in series is formed, and an ambient temperature sensor for measuring an ambient temperature which is not affected by a fluid flow is provided on one side other than the one side. In addition, a differential amplifier circuit for controlling the current flowing through the heating element is provided so that the voltage difference between the respective middle points of the bridge circuit becomes constant. Further, in one configuration example of the flow velocity sensor of the present invention, at least one voltage follower circuit receives the voltage across the first and second temperature measuring resistance elements connected in series, and the voltage division between the voltage across the both ends is performed. The flow velocity is obtained by comparing the voltage at the connection point of the first and second temperature measuring resistance elements.
【００１１】[0011]
【発明の実施の形態】［第１の実施の形態］以下、本発
明の実施の形態について図面を参照して詳細に説明す
る。図１（ａ）は本発明の第１の実施の形態となる流速
センサの平面図、図１（ｂ）は図１（ａ）のＩ−Ｉ線断
面図、図２は図１（ａ），（ｂ）の流速センサの電気回
路図である。BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1A is a plan view of a flow velocity sensor according to a first embodiment of the present invention, FIG. 1B is a sectional view taken along the line I-I of FIG. 1A, and FIG. 2 is FIG. , (B) are electrical circuit diagrams of the flow velocity sensor.
【００１２】本実施の形態の流速センサは、単結晶シリ
コンなどからなる基台１上に形成され、この基台１の中
央部には、例えば異方性エッチング等によって空隙部２
が形成されている。また、基台１上には、空隙部２によ
って基台１から空間的に隔離された薄膜層（ダイアフラ
ム部材）３が形成されている。ガス等の流体は、この薄
膜層３上を通過する。The flow velocity sensor of this embodiment is formed on a base 1 made of single crystal silicon or the like, and a void 2 is formed in the center of the base 1 by anisotropic etching or the like.
Are formed. A thin film layer (diaphragm member) 3 spatially separated from the base 1 by a void 2 is formed on the base 1. A fluid such as gas passes over the thin film layer 3.
【００１３】薄膜層３には、空隙部２を介して連通する
対をなすスリット４ａ，４ｂが互いに所定の間隔をおい
て設けられている。さらに、これらのスリット４ａ，４
ｂの間には、スリット４ａ，４ｂの間を結ぶ直線と直交
する方向に延びるスリット５が設けられており、このス
リット５により、図１に示す流体の流れる方向に沿って
スリット４ａ，４ｂの間に２つの配設部６ａ，６ｂが形
成されている。配設部６ａ，６ｂは、スリット５により
互いに熱的に絶縁されている。The thin film layer 3 is provided with a pair of slits 4a and 4b which communicate with each other through the void portion 2 at a predetermined interval. Furthermore, these slits 4a, 4
Between b, a slit 5 extending in a direction orthogonal to a straight line connecting the slits 4a and 4b is provided, and by this slit 5, the slits 4a and 4b are formed along the fluid flow direction shown in FIG. Two arrangement portions 6a and 6b are formed between them. The arrangement portions 6a and 6b are thermally insulated from each other by the slit 5.
【００１４】配設部６ａには、発熱体兼温度センサとし
て機能する測温抵抗エレメントＡが薄膜形成技術により
形成され、同様に、配設部６ｂには、発熱体兼温度セン
サとして機能する測温抵抗エレメントＢが薄膜形成技術
により形成されている。また、薄膜層３と基台１とが熱
的に接する部分、すなわち空隙部２が設けられていない
部分には、周囲温度（流体の温度）により抵抗値が変化
する周囲温度測温抵抗エレメントＣが薄膜形成技術によ
り形成されている。A temperature measuring resistance element A which functions as a heating element and a temperature sensor is formed in the arranging portion 6a by a thin film forming technique, and similarly, a temperature measuring resistance element which functions as a heating element and a temperature sensor is formed in the arranging portion 6b. The temperature resistance element B is formed by a thin film forming technique. Further, in a portion where the thin film layer 3 and the base 1 are in thermal contact, that is, in a portion where the void 2 is not provided, an ambient temperature temperature measuring resistance element C whose resistance value changes according to ambient temperature (fluid temperature) Are formed by a thin film forming technique.
【００１５】７，８は測温抵抗エレメントＡの両端を外
部の電気回路と接続するためのパッド、９，１０は測温
抵抗エレメントＢの両端を電気回路と接続するためのパ
ッド、１１，１２は周囲温度測温抵抗エレメントＣの両
端を電気回路と接続するためのパッドである。Reference numerals 7 and 8 are pads for connecting both ends of the temperature measuring resistance element A to an external electric circuit. Reference numerals 9 and 10 are pads for connecting both ends of the temperature measuring resistance element B to the electric circuit. Are pads for connecting both ends of the ambient temperature measuring resistance element C to an electric circuit.
【００１６】次に、本実施の形態の流速センサの電気回
路を図２を用いて説明する。本実施の形態の流速センサ
の電気回路は、基台１上を移動する流体の流速を測定す
るためのものであり、ブリッジ回路２１と、差動増幅回
路２２と、出力回路２３とを有している。ブリッジ回路
２１は、抵抗Ｒ１と測温抵抗エレメントＡと測温抵抗エ
レメントＢとを直列に接続した第１の直列回路と、抵抗
Ｒ２と抵抗Ｒ３と周囲温度測温抵抗エレメントＣとを直
列に接続した第２の直列回路とからなり、第１の直列回
路と第２の直列回路とを並列に接続することで構成され
ている。Next, an electric circuit of the flow velocity sensor of this embodiment will be described with reference to FIG. The electric circuit of the flow velocity sensor of this embodiment is for measuring the flow velocity of the fluid moving on the base 1, and has a bridge circuit 21, a differential amplifier circuit 22, and an output circuit 23. ing. The bridge circuit 21 includes a first series circuit in which a resistor R1, a temperature measuring resistance element A, and a temperature measuring resistance element B are connected in series, and a resistor R2, a resistor R3, and an ambient temperature temperature measuring resistance element C are connected in series. And the second series circuit described above, and is configured by connecting the first series circuit and the second series circuit in parallel.
【００１７】差動増幅回路２２は、反転入力端子が抵抗
Ｒ１と測温抵抗エレメントＡの接続点に接続され、非反
転入力端子が抵抗Ｒ２と抵抗Ｒ３の接続点に接続され、
出力端子が抵抗Ｒ１と抵抗Ｒ２の接続点に接続された演
算増幅器Ａ１から構成される。In the differential amplifier circuit 22, the inverting input terminal is connected to the connection point of the resistance R1 and the temperature measuring resistance element A, and the non-inverting input terminal is connected to the connection point of the resistance R2 and the resistance R3.
The output terminal is composed of an operational amplifier A1 connected to the connection point of the resistors R1 and R2.
【００１８】このような構成により、差動増幅回路２２
は、抵抗Ｒ２と抵抗Ｒ３の接続点の電位Ｖ１と、抵抗Ｒ
１と測温抵抗エレメントＡの接続点の電位Ｖ２との差分
値を増幅した出力電圧Ｖｏをブリッジ回路２１の抵抗Ｒ
１と抵抗Ｒ２の接続点に印加する。With such a configuration, the differential amplifier circuit 22
Is the potential V1 at the connection point of the resistor R2 and the resistor R3, and the resistor R
1 and the output voltage Vo obtained by amplifying the difference value between the potential V2 at the connection point of the temperature measuring resistance element A and the resistance R of the bridge circuit 21.
1 is applied to the connection point of the resistor R2.
【００１９】出力回路２３は、非反転入力端子が抵抗Ｒ
１と測温抵抗エレメントＡの接続点に接続され、反転入
力端子と出力端子とが接続された演算増幅器Ａ２と、一
端が演算増幅器Ａ２の出力端子に接続された抵抗Ｒ５
と、一端が抵抗Ｒ５の他端と接続され、他端が接地され
た抵抗Ｒ６と、非反転入力端子が測温抵抗エレメントＡ
と測温抵抗エレメントＢの接続点に接続され、反転入力
端子が抵抗Ｒ５と抵抗Ｒ６の接続点に接続された演算増
幅器Ａ３とから構成される。In the output circuit 23, the non-inverting input terminal has a resistor R.
1 is connected to the connection point of the temperature measuring resistance element A, and an operational amplifier A2 having an inverting input terminal and an output terminal connected thereto, and a resistor R5 having one end connected to the output terminal of the operational amplifier A2
And a resistor R6 having one end connected to the other end of the resistor R5 and the other end grounded, and the non-inverting input terminal of the temperature measuring resistor element A.
And an operational amplifier A3 connected to the connection point of the temperature measuring resistance element B and having an inverting input terminal connected to the connection point of the resistors R5 and R6.
【００２０】ブリッジ回路２１の平衡条件は、抵抗Ｒ１
の抵抗値／（測温抵抗エレメントＡの抵抗値＋測温抵抗
エレメントＢの抵抗値）＝抵抗Ｒ２の抵抗値／（抵抗Ｒ
３の抵抗値＋周囲温度測温抵抗エレメントＣの抵抗値）
である。なお、本実施の形態では、室温などの基準とな
る周囲温度において抵抗Ｒ２の抵抗値＝抵抗Ｒ３の抵抗
値＋周囲温度測温抵抗エレメントＣの抵抗値となるよう
に、また抵抗Ｒ１の抵抗値＝（測温抵抗エレメントＡの
抵抗値＋測温抵抗エレメントＢの抵抗値）の設定温度に
おける抵抗値となるように設定されている。抵抗Ｒ３
は、測温抵抗エレメントＡ，Ｂの平均温度と周囲温度測
温抵抗エレメントＣの温度差を維持するための調整用抵
抗である。なお、流速センサの温度特性を補正する目的
のため、上記温度差を一定とせずに、例えば周囲温度が
高くなるほどこの差を大きくするというように変化させ
てもよい。The balance condition of the bridge circuit 21 is that the resistance R1
Resistance value / (resistance value of resistance temperature element A + resistance value of resistance temperature element B) = resistance value of resistance R2 / (resistance R
(Resistance value of 3 + resistance value of ambient temperature measuring resistance element C)
Is. In the present embodiment, the resistance value of the resistor R2 = the resistance value of the resistor R3 + the resistance value of the ambient temperature resistance measuring element C at the reference ambient temperature such as room temperature, and the resistance value of the resistor R1. = (Resistance value of resistance temperature element A + resistance value of resistance temperature element B) at the set temperature. Resistance R3
Is an adjusting resistor for maintaining the temperature difference between the average temperature of the temperature measuring resistance elements A and B and the ambient temperature measuring resistance element C. For the purpose of correcting the temperature characteristic of the flow velocity sensor, the temperature difference may not be constant, but may be changed such that the higher the ambient temperature is, the larger the difference becomes.
【００２１】差動増幅回路２２の演算増幅器Ａ１からブ
リッジ回路２１の抵抗Ｒ１，Ｒ２に電圧が印加される
と、測温抵抗エレメントＡ，Ｂに電流が流れてこれらが
発熱し、その結果、測温抵抗エレメントＡ，Ｂの抵抗値
が増加して、前記平衡条件が成立するところでバランス
する。When a voltage is applied from the operational amplifier A1 of the differential amplifier circuit 22 to the resistors R1 and R2 of the bridge circuit 21, a current flows through the temperature measuring resistance elements A and B, which generate heat, resulting in the measurement. The resistance values of the temperature resistance elements A and B are increased and balanced when the equilibrium condition is satisfied.
【００２２】ここで、周囲温度が上昇して周囲温度測温
抵抗エレメントＣの抵抗値が増加すると、ブリッジ回路
２１の平衡が失われ、抵抗Ｒ２と抵抗Ｒ３の接続点の電
位Ｖ１が上昇するので、差動増幅回路２２は、ブリッジ
回路２１を再度平衡にさせるべく、ブリッジ回路２１へ
の印加電圧Ｖｏを上昇させる。これにより、測温抵抗エ
レメントＡ，Ｂに供給される電流が増加するので、測温
抵抗エレメントＡ，Ｂの発熱量が増大し、測温抵抗エレ
メントＡ，Ｂの抵抗値が増加して、前記平衡条件が成立
するところでバランスする。When the ambient temperature rises and the resistance value of the ambient temperature measuring resistance element C increases, the balance of the bridge circuit 21 is lost and the potential V1 at the connection point of the resistors R2 and R3 rises. The differential amplifier circuit 22 raises the applied voltage Vo to the bridge circuit 21 in order to rebalance the bridge circuit 21. As a result, the current supplied to the temperature measuring resistance elements A and B increases, so that the calorific value of the temperature measuring resistance elements A and B increases, and the resistance value of the temperature measuring resistance elements A and B increases, and Balance when the equilibrium condition is satisfied.
【００２３】周囲温度が低下して周囲温度測温抵抗エレ
メントＣの抵抗値が減少すると、抵抗Ｒ２と抵抗Ｒ３の
接続点の電位Ｖ１が低下するので、差動増幅回路２２
は、ブリッジ回路２１への印加電圧Ｖｏを低下させる。
これにより、測温抵抗エレメントＡ，Ｂの発熱量が減少
し、測温抵抗エレメントＡ，Ｂの抵抗値が減少して、前
記平衡条件が成立するところでバランスする。When the ambient temperature decreases and the resistance value of the ambient temperature measuring resistance element C decreases, the potential V1 at the connection point of the resistors R2 and R3 decreases, so the differential amplifier circuit 22
Reduces the voltage Vo applied to the bridge circuit 21.
As a result, the calorific value of the temperature measuring resistance elements A and B is reduced, the resistance values of the temperature measuring resistance elements A and B are reduced, and balance is achieved when the equilibrium condition is satisfied.
【００２４】一方、流体に流速が生じると、測温抵抗エ
レメントＡ，Ｂが冷やされ、測温抵抗エレメントＡ，Ｂ
の抵抗値が下がり、抵抗Ｒ１と測温抵抗エレメントＡの
接続点の電位Ｖ２が低下するので、差動増幅回路２２
は、ブリッジ回路２１への印加電圧Ｖｏを上昇させる。
これにより、測温抵抗エレメントＡ，Ｂの発熱量が増大
し、測温抵抗エレメントＡ，Ｂの抵抗値が増加して、前
記平衡条件が成立するところでバランスする。On the other hand, when the flow velocity is generated in the fluid, the temperature measuring resistance elements A and B are cooled, and the temperature measuring resistance elements A and B are cooled.
The resistance value of the differential amplifier circuit 22 decreases, and the potential V2 of the connection point between the resistance R1 and the temperature measuring resistance element A decreases.
Raises the voltage Vo applied to the bridge circuit 21.
As a result, the calorific value of the temperature measuring resistance elements A and B is increased, the resistance values of the temperature measuring resistance elements A and B are increased, and balance is achieved when the equilibrium condition is satisfied.
【００２５】また、流速が減少して、測温抵抗エレメン
トＡ，Ｂの抵抗値が上昇すると、抵抗Ｒ１と測温抵抗エ
レメントＡの接続点の電位Ｖ２が上昇するので、差動増
幅回路２２は、ブリッジ回路２１への印加電圧Ｖｏを低
下させる。これにより、測温抵抗エレメントＡ，Ｂの発
熱量が減少し、測温抵抗エレメントＡ，Ｂの抵抗値が減
少して、前記平衡条件が成立するところでバランスす
る。When the flow velocity decreases and the resistance values of the temperature measuring resistance elements A and B increase, the potential V2 at the connection point between the resistance R1 and the temperature measuring resistance element A increases, so that the differential amplifier circuit 22 , The voltage Vo applied to the bridge circuit 21 is reduced. As a result, the calorific value of the temperature measuring resistance elements A and B is reduced, the resistance values of the temperature measuring resistance elements A and B are reduced, and balance is achieved when the equilibrium condition is satisfied.
【００２６】以上のように、差動増幅回路２２は、測温
抵抗エレメントＡ，Ｂで検出される温度（エレメント
Ａ，Ｂで検出される温度の平均値）が周囲温度測温抵抗
エレメントＣで検出される周囲温度よりも常に一定温度
高くなるように、測温抵抗エレメントＡ，Ｂを発熱させ
る。As described above, in the differential amplifier circuit 22, the temperature detected by the temperature measuring resistance elements A and B (the average value of the temperatures detected by the elements A and B) is the ambient temperature measuring resistance element C. The temperature measuring resistance elements A and B are caused to generate heat so that the temperature is always higher than the detected ambient temperature.
【００２７】次に、演算増幅器Ａ２はボルテージフォロ
アを構成している。抵抗Ｒ５，Ｒ６からなる直列回路
は、このボルテージフォロアＡ２を介して測温抵抗エレ
メントＡ，Ｂからなる直列回路に接続されている。ボル
テージフォロアを用いることにより、ブリッジ回路２１
内を流れる電流が抵抗Ｒ５，Ｒ６に流出しないようにし
ている。Next, the operational amplifier A2 constitutes a voltage follower. The series circuit composed of the resistors R5 and R6 is connected to the series circuit composed of the temperature measuring resistance elements A and B via the voltage follower A2. By using the voltage follower, the bridge circuit 21
The current flowing inside is prevented from flowing out to the resistors R5 and R6.
【００２８】抵抗Ｒ５，Ｒ６は、一般的には流速が０の
とき、抵抗Ｒ５の抵抗値／抵抗Ｒ６の抵抗値＝測温抵抗
エレメントＡの抵抗値／測温抵抗エレメントＢの抵抗値
が成立するように設定されている。したがって、流速が
０のとき、測温抵抗エレメントＡと測温抵抗エレメント
Ｂの接続点の電位Ｖ３と、抵抗Ｒ５と抵抗Ｒ６の接続点
の電位Ｖ４が同電位となるので、演算増幅器Ａ３の出力
電圧は０となる。なお、上記のように設定せずに、流速
が０のときの出力電圧を流速０の出力電圧として校正し
たり、オフセットをもたせて流速０のとき任意の電圧値
になるように設定してもよい。Generally, when the flow velocity is 0, the resistances of the resistors R5 and R6 are such that the resistance value of the resistance R5 / the resistance value of the resistance R6 = the resistance value of the temperature measuring resistance element A / the resistance value of the temperature measuring resistance element B. Is set to. Therefore, when the flow velocity is 0, the potential V3 at the connection point between the temperature measurement resistance element A and the temperature measurement resistance element B and the potential V4 at the connection point between the resistance R5 and the resistance R6 become the same potential, so the output of the operational amplifier A3. The voltage becomes 0. It should be noted that, instead of the above setting, the output voltage when the flow velocity is 0 may be calibrated as the output voltage of the flow velocity 0, or may be set to have an arbitrary voltage value when the flow velocity is 0 by providing an offset. Good.
【００２９】前述のように、流体に流速が生じると、測
温抵抗エレメントＡ，Ｂが冷やされる。このとき、上流
側に位置する測温抵抗エレメントＡは、下流側に位置す
る測温抵抗エレメントＢに比べてより強く冷やされるの
で、測温抵抗エレメントＡの抵抗値が測温抵抗エレメン
トＢの抵抗値よりも小さくなる。その結果、測温抵抗エ
レメントＡと測温抵抗エレメントＢの接続点の電位Ｖ３
が上昇するので、電位Ｖ３と、抵抗Ｒ５と抵抗Ｒ６の接
続点の電位Ｖ４とに差が生じる。演算増幅器Ａ３は、流
速に応じた出力電圧、すなわち（Ｖ３−Ｖ４）に比例し
た電圧を出力する。As described above, when the flow velocity is generated in the fluid, the temperature measuring resistance elements A and B are cooled. At this time, since the temperature measuring resistance element A located on the upstream side is cooled more strongly than the temperature measuring resistance element B located on the downstream side, the resistance value of the temperature measuring resistance element A is the resistance of the temperature measuring resistance element B. It is smaller than the value. As a result, the potential V3 at the connection point between the temperature measuring resistance element A and the temperature measuring resistance element B
Rises, a difference occurs between the potential V3 and the potential V4 at the connection point of the resistors R5 and R6. The operational amplifier A3 outputs an output voltage according to the flow velocity, that is, a voltage proportional to (V3-V4).
【００３０】以上のように、本実施の形態では、周囲温
度や流速に関係なく、測温抵抗エレメントＡ，Ｂで検出
する温度の平均値が周囲温度よりも常に一定温度高くな
るように測温抵抗エレメントＡ，Ｂを発熱させるので、
流速が増加したときに、測温抵抗エレメントＡ，Ｂの抵
抗値の差が減少して感度が低下することがなくなる。As described above, in the present embodiment, the temperature is measured such that the average value of the temperatures detected by the temperature measuring resistance elements A and B is always higher than the ambient temperature by a constant temperature regardless of the ambient temperature and the flow velocity. Since the resistance elements A and B generate heat,
When the flow velocity increases, the difference between the resistance values of the temperature measuring resistance elements A and B decreases and the sensitivity does not decrease.
【００３１】また、本実施の形態では、測温抵抗エレメ
ントＡ，Ｂからなる直列回路と、抵抗Ｒ５，Ｒ６からな
る直列回路とを並列に接続している。したがって、周囲
温度又は流速の変化により、ブリッジ回路２１への印加
電圧Ｖｏが変化して、電圧Ｖ２が変化しても、これに応
じて抵抗Ｒ５の端子電圧（ボルテージフォロアＡ２の出
力電圧）も電圧Ｖ２と同じ値に変化するので、測温抵抗
エレメントＡ，Ｂのリファレンス電位（電位Ｖ４）は、
電圧Ｖ２に所定比Ｒ６／（Ｒ５＋Ｒ６）をかけた値に常
に調整される。その結果、電位差Ｖ３−Ｖ４は、流速の
みを反映した値となり、流速の増大に伴ってほぼ直線的
に増加する特性が得られる。Further, in the present embodiment, the series circuit composed of the temperature measuring resistance elements A and B and the series circuit composed of the resistors R5 and R6 are connected in parallel. Therefore, even if the applied voltage Vo to the bridge circuit 21 changes due to the change of the ambient temperature or the flow velocity and the voltage V2 changes, the terminal voltage of the resistor R5 (the output voltage of the voltage follower A2) also changes accordingly. Since it changes to the same value as V2, the reference potential (potential V4) of the temperature measuring resistance elements A and B is
It is constantly adjusted to a value obtained by multiplying the voltage V2 by a predetermined ratio R6 / (R5 + R6). As a result, the potential difference V3-V4 becomes a value that reflects only the flow velocity, and a characteristic that increases almost linearly with the increase of the flow velocity is obtained.
【００３２】［第２の実施の形態］図３は本発明の第２
の実施の形態となる流速センサの平面図、図４は図３の
流速センサの電気回路図であり、図１、図２と同一の構
成には同一の符号を付してある。本実施の形態では、配
設部６ａに、温度センサとして機能する測温抵抗エレメ
ントＡ’と、発熱体として機能する発熱抵抗エレメント
Ｄとが薄膜形成技術により形成されている。同様に、配
設部６ｂには、温度センサとして機能する測温抵抗エレ
メントＢ’と、発熱体として機能する発熱抵抗エレメン
トＥとが薄膜形成技術により形成されている。[Second Embodiment] FIG. 3 shows a second embodiment of the present invention.
4 is a plan view of the flow velocity sensor according to the embodiment of the present invention, FIG. 4 is an electric circuit diagram of the flow velocity sensor of FIG. 3, and the same components as those in FIGS. 1 and 2 are designated by the same reference numerals. In the present embodiment, the temperature measuring resistance element A ′ functioning as a temperature sensor and the heat generating resistance element D functioning as a heating element are formed in the arrangement portion 6a by a thin film forming technique. Similarly, a temperature measuring resistance element B ′ functioning as a temperature sensor and a heat generating resistance element E functioning as a heating element are formed in the arrangement portion 6b by a thin film forming technique.
【００３３】７，８は測温抵抗エレメントＡ’の両端を
電気回路と接続するためのパッド、９，１０は測温抵抗
エレメントＢ’の両端を電気回路と接続するためのパッ
ド、１３，１４は発熱抵抗エレメントＤの両端を外部の
電気回路と接続するためのパッド、１５，１６は発熱抵
抗エレメントＥの両端を電気回路と接続するためのパッ
ドである。Reference numerals 7 and 8 are pads for connecting both ends of the temperature measuring resistance element A'to an electric circuit. Reference numerals 9 and 10 are pads for connecting both ends of the temperature measuring resistance element B'to the electric circuit. Is a pad for connecting both ends of the heating resistor element D to an external electric circuit, and 15, 16 are pads for connecting both ends of the heating resistor element E to an electric circuit.
【００３４】本実施の形態のブリッジ回路２１ａは、発
熱体兼温度センサとして機能する測温抵抗エレメント
Ａ，Ｂの代わりに、温度センサとして機能する測温抵抗
エレメントＡ’，Ｂ’を用いている。また、本実施の形
態では、ブリッジ回路２１ａの抵抗Ｒ１と抵抗Ｒ２の接
続点に一定電圧Ｖｓを印加し、非反転入力端子が抵抗Ｒ
２と抵抗Ｒ３の接続点に接続され、反転入力端子が抵抗
Ｒ１と測温抵抗エレメントＡ’の接続点に接続された演
算増幅器Ａ４を用いている。演算増幅器Ａ４の出力端子
には、発熱抵抗エレメントＤと発熱抵抗エレメントＥと
が直列に接続されている。The bridge circuit 21a of the present embodiment uses temperature measuring resistance elements A'and B'which function as temperature sensors instead of the temperature measuring resistance elements A and B which also function as heating elements and temperature sensors. . In addition, in the present embodiment, a constant voltage Vs is applied to the connection point between the resistors R1 and R2 of the bridge circuit 21a, and the non-inverting input terminal has the resistor R1.
The operational amplifier A4 is used, which is connected to the connection point of the resistor R3 and the resistor R3 and whose inverting input terminal is connected to the connection point of the resistor R1 and the temperature measuring resistance element A '. A heating resistance element D and a heating resistance element E are connected in series to the output terminal of the operational amplifier A4.
【００３５】ブリッジ回路２１ａの平衡条件は、抵抗Ｒ
１の抵抗値／（測温抵抗エレメントＡ’の抵抗値＋測温
抵抗エレメントＢ’の抵抗値）＝抵抗Ｒ２の抵抗値／
（抵抗Ｒ３の抵抗値＋周囲温度測温抵抗エレメントＣの
抵抗値）である。ブリッジ回路２１ａに電圧Ｖｓが印加
されると、演算増幅器Ａ４は、抵抗Ｒ２と抵抗Ｒ３の接
続点の電位Ｖ１と、抵抗Ｒ１と測温抵抗エレメントＡ’
の接続点の電位Ｖ２との差分電圧Ｖ１−Ｖ２を増幅して
出力する。The balance condition of the bridge circuit 21a is that the resistance R
1 resistance value / (resistance value of resistance temperature element A ′ + resistance value of resistance temperature element B ′) = resistance value of resistance R2 /
(Resistance value of resistance R3 + resistance value of ambient temperature measuring resistance element C). When the voltage Vs is applied to the bridge circuit 21a, the operational amplifier A4 causes the potential V1 at the connection point of the resistors R2 and R3, the resistor R1 and the temperature measuring resistance element A '.
The differential voltage V1-V2 with respect to the potential V2 at the connection point is amplified and output.
【００３６】これにより、発熱抵抗エレメントＤ，Ｅに
電流が流れてこれらが発熱し、その結果、発熱抵抗エレ
メントＤ，Ｅの近傍に配置された測温抵抗エレメント
Ａ’，Ｂ’の温度が上昇して、測温抵抗エレメント
Ａ’，Ｂ’の抵抗値が増加し、前記平衡条件が成立する
ところでバランスする。As a result, a current flows through the heating resistance elements D and E to generate heat, and as a result, the temperature of the temperature measuring resistance elements A ′ and B ′ arranged near the heating resistance elements D and E rises. Then, the resistance values of the temperature measuring resistance elements A'and B'increase, and the resistance is balanced when the equilibrium condition is satisfied.
【００３７】ここで、周囲温度が上昇して周囲温度測温
抵抗エレメントＣの抵抗値が増加すると、抵抗Ｒ２と抵
抗Ｒ３の接続点の電位Ｖ１が上昇するので、演算増幅器
Ａ４は、出力電圧を上昇させる。これにより、発熱抵抗
エレメントＤ，Ｅに供給される電流が増加するので、発
熱抵抗エレメントＤ，Ｅの発熱量が増大し、測温抵抗エ
レメントＡ’，Ｂ’の抵抗値が増加して、前記平衡条件
が成立するところでバランスする。When the ambient temperature rises and the resistance value of the ambient temperature measuring resistance element C increases, the potential V1 at the connection point of the resistors R2 and R3 rises, so that the operational amplifier A4 outputs the output voltage. To raise. As a result, the current supplied to the heating resistance elements D and E increases, so that the heat generation amount of the heating resistance elements D and E increases, and the resistance values of the temperature measuring resistance elements A ′ and B ′ increase. Balance when the equilibrium condition is satisfied.
【００３８】周囲温度が低下して周囲温度測温抵抗エレ
メントＣの抵抗値が減少すると、抵抗Ｒ２と抵抗Ｒ３の
接続点の電位Ｖ１が低下するので、演算増幅器Ａ４は、
出力電圧を低下させる。これにより、発熱抵抗エレメン
トＤ，Ｅの発熱量が減少し、測温抵抗エレメントＡ’，
Ｂ’の抵抗値が減少して、前記平衡条件が成立するとこ
ろでバランスする。When the ambient temperature decreases and the resistance value of the ambient temperature measuring resistance element C decreases, the potential V1 at the connection point of the resistors R2 and R3 decreases, so that the operational amplifier A4 operates as follows.
Reduce the output voltage. As a result, the amount of heat generated by the heating resistance elements D, E is reduced, and the temperature measuring resistance elements A ',
When the resistance value of B'decreases and the equilibrium condition is satisfied, balance is achieved.
【００３９】一方、流体に流速が生じると、測温抵抗エ
レメントＡ’，Ｂ’の抵抗値が下がり、抵抗Ｒ１と測温
抵抗エレメントＡ’の接続点の電位Ｖ２が低下するの
で、演算増幅器Ａ４は、出力電圧を上昇させる。これに
より、発熱抵抗エレメントＤ，Ｅの発熱量が増大し、測
温抵抗エレメントＡ’，Ｂ’の抵抗値が増加して、前記
平衡条件が成立するところでバランスする。On the other hand, when a flow velocity is generated in the fluid, the resistance values of the temperature measuring resistance elements A'and B'decrease, and the potential V2 at the connection point of the resistance R1 and the temperature measuring resistance element A'decreases. Therefore, the operational amplifier A4 Raises the output voltage. As a result, the amount of heat generated by the heating resistance elements D and E increases, the resistance values of the temperature measuring resistance elements A ′ and B ′ increase, and balance occurs when the equilibrium condition is satisfied.
【００４０】また、流速が減少して、測温抵抗エレメン
トＡ’，Ｂ’の抵抗値が上昇すると、抵抗Ｒ１と測温抵
抗エレメントＡの接続点の電位Ｖ２が上昇するので、演
算増幅器Ａ４は、出力電圧を低下させる。これにより、
発熱抵抗エレメントＤ，Ｅの発熱量が減少し、測温抵抗
エレメントＡ’，Ｂ’の抵抗値が減少して、前記平衡条
件が成立するところでバランスする。以上のようにし
て、第１の実施の形態と同様の効果を得ることができ
る。なお、出力回路２３の構成とその動作は、第１の実
施の形態と全く同じである。When the flow velocity decreases and the resistance values of the temperature measuring resistance elements A'and B'increase, the potential V2 at the connection point between the resistance R1 and the temperature measuring resistance element A rises. , Reduce the output voltage. This allows
The heat generation amount of the heat generation resistance elements D and E decreases, the resistance values of the temperature measurement resistance elements A ′ and B ′ decrease, and balance is achieved when the equilibrium condition is satisfied. As described above, the same effect as that of the first embodiment can be obtained. The configuration and operation of the output circuit 23 are exactly the same as in the first embodiment.
【００４１】なお、第１、第２の実施の形態において、
抵抗Ｒ３を削除して抵抗Ｒ２と周囲温度測温抵抗エレメ
ントＣを直結し、その代わりに、測温抵抗エレメント
Ａ，Ｂ（Ａ’，Ｂ’）からなる直列回路と並列に抵抗を
追加することにより、測温抵抗エレメントＡ’，Ｂ’と
周囲温度測温抵抗エレメントＣとの温度差を維持するた
めの調整をしてもよい。また、第１、第２の実施の形態
では、単結晶シリコンからなる基台１を用いているが、
ステンレス、セラミック、サファイア等からなる基台を
用いてもよい。In the first and second embodiments,
The resistor R3 is deleted to directly connect the resistor R2 and the ambient temperature measuring resistance element C, and instead, a resistor is added in parallel with the series circuit including the temperature measuring resistance elements A and B (A ', B'). Therefore, adjustment may be performed to maintain the temperature difference between the temperature measuring resistance elements A ′ and B ′ and the ambient temperature measuring resistance element C. Further, in the first and second embodiments, the base 1 made of single crystal silicon is used,
A base made of stainless steel, ceramic, sapphire or the like may be used.
【００４２】また、第１、第２の実施の形態では、ブリ
ッジ回路と差動増幅回路を用いて直列に接続された２つ
の測温抵抗エレメントの平均温度を周囲温度測温抵抗エ
レメントで測定された周囲温度よりもある一定温度高く
なるようにする実施の形態について説明したが、マイコ
ンなどを用いて周囲温度よりも直列に接続された２つの
測温抵抗エレメントの平均温度がある一定温度高くなる
ように電流または電圧を制御してもよい。つまり、直列
に接続された２つの測温抵抗エレメントの設定目標とす
る平均温度における直列抵抗値を温度と抵抗値の関係式
から求め、その抵抗値になるように印加する電流または
電圧を制御してもよい。なお、この場合は周囲温度の計
測に外付けの一般的な温度センサを使用してもよい。さ
らに、図１、図３において、スリット５をなくしてもよ
く、１つの測温抵抗体の中点から配線を取り出すように
して、実質上２つの測温抵抗体として使用してもよい。In the first and second embodiments, the average temperature of two temperature measuring resistance elements connected in series by using the bridge circuit and the differential amplifier circuit is measured by the ambient temperature measuring resistance element. Although the embodiment has been described in which the temperature is higher than the ambient temperature by a certain temperature, the average temperature of two temperature measuring resistance elements connected in series is higher than the ambient temperature by a certain temperature by using a microcomputer or the like. Current or voltage may be controlled as described above. That is, the series resistance value at the average temperature that is the setting target of the two resistance temperature measuring elements connected in series is calculated from the relational expression between the temperature and the resistance value, and the applied current or voltage is controlled so that the resistance value is achieved. May be. In this case, a general external temperature sensor may be used to measure the ambient temperature. Further, in FIG. 1 and FIG. 3, the slit 5 may be omitted, and the wiring may be taken out from the midpoint of one resistance temperature detector to be used substantially as two resistance temperature detectors.
【００４３】［第３の実施の形態］図５は本発明の第３
の実施の形態となる流速センサの断面図であり、図１、
図２と同一の構成には同一の符号を付してある。第１、
第２の実施の形態では、流体の流れの中にエレメント
Ａ，Ｂ，Ｃを設けたが、本実施の形態は、基台３２に形
成された薄肉部（ダイアフラム部）３３の流路側と反対
側の被測定流体に直接接しない面にエレメントＡ，Ｂ，
Ｃを設けたものである。[Third Embodiment] FIG. 5 shows a third embodiment of the present invention.
2 is a cross-sectional view of the flow velocity sensor according to the embodiment of FIG.
The same components as those in FIG. 2 are designated by the same reference numerals. First,
In the second embodiment, the elements A, B and C are provided in the flow of the fluid, but in the present embodiment, the flow path side of the thin portion (diaphragm portion) 33 formed on the base 32 is opposite. Element A, B, on the side not directly contacting the fluid to be measured.
C is provided.
【００４４】図５において、３１はステンレスからなる
流路形成部材、３２は流路形成部材３１上に設置され
た、ステンレスからなる基台、３３は基台３２に形成さ
れた薄肉部（ダイアフラム部）、３４は基台３２上に形
成された酸化シリコン、窒化シリコン、アルミナあるい
はポリイミド等の電気絶縁膜である。流路形成部材３１
は流体の流路３６を形成する２つの貫通孔３７，３８を
有している。基台３２の下面中央に長円状の凹部３５が
形成されることにより、この凹部３５が形成されている
表面側が薄肉部（ダイアフラム部）３３を形成してい
る。凹部３５は、その両端部において貫通孔３７，３８
と連通する。なお、凹部３５は、流体の流れをスムーズ
に流すために長円状が好ましいが、これに限らず矩形状
や円形状でもよい。In FIG. 5, 31 is a flow passage forming member made of stainless steel, 32 is a base made of stainless steel installed on the flow passage forming member 31, and 33 is a thin wall portion (diaphragm portion) formed on the base 32. ) And 34 are electrical insulating films formed on the base 32, such as silicon oxide, silicon nitride, alumina, or polyimide. Flow path forming member 31
Has two through holes 37 and 38 forming a fluid passage 36. By forming an oval concave portion 35 in the center of the lower surface of the base 32, a thin portion (diaphragm portion) 33 is formed on the surface side where the concave portion 35 is formed. The recess 35 has through holes 37, 38 at both ends thereof.
Communicate with. The recess 35 is preferably an elliptical shape in order to smoothly flow the fluid, but the shape is not limited to this and may be a rectangular shape or a circular shape.
【００４５】基台３２の上面には、電気絶縁膜３４が全
面にわたって形成されており、この電気絶縁膜３４の表
面に測温抵抗エレメントＡ，Ｂや周囲温度測温抵抗エレ
メントＣ、パッド７〜１２が第１の実施の形態と同様に
形成されている。電気回路は、図２に示したとおりであ
る。また、上記とは逆に凹部３５の底面に電気絶縁膜を
全面にわたって形成し、この電気絶縁膜の表面に測温抵
抗エレメントＡ，Ｂとパッドを同様に形成し、周囲温度
測温抵抗エレメントＣは、基台３２の厚肉部に電気絶縁
膜を介してパッドと共に同様に形成し、その反対側の面
に流体を流してもよい。An electric insulating film 34 is formed over the entire surface of the base 32, and the temperature measuring resistance elements A and B, the ambient temperature measuring resistance element C, and the pads 7 to 7 are formed on the surface of the electric insulating film 34. 12 is formed similarly to the first embodiment. The electric circuit is as shown in FIG. Contrary to the above, an electric insulating film is formed over the entire bottom surface of the concave portion 35, and the temperature measuring resistance elements A and B and the pad are similarly formed on the surface of the electric insulating film, and the ambient temperature measuring resistance element C is formed. May be formed on the thick portion of the base 32 in the same manner as the pad via the electric insulating film, and the fluid may flow to the surface on the opposite side.
【００４６】なお、第１の実施の形態の測温抵抗エレメ
ントＡ，Ｂや周囲温度測温抵抗エレメントＣ、パッド７
〜１２の代わりに、第２の実施の形態の測温抵抗エレメ
ントＡ’，Ｂ’や周囲温度測温抵抗エレメントＣ、発熱
抵抗エレメントＤ，Ｅ、パッド７〜１６を形成してもよ
いことは言うまでもない。この場合の電気回路は、図３
に示したとおりである。なお、本発明の第１〜第３の実
施の形態におけるエレメントＡ，Ｂ，Ｃ，Ａ’，Ｂ’，
Ｄ，Ｅはすべて白金薄膜などで形成するのが好ましい
が、これに限らない。The temperature measuring resistance elements A and B, the ambient temperature measuring resistance element C, and the pad 7 of the first embodiment are used.
It is possible to form the temperature measuring resistance elements A ′ and B ′, the ambient temperature measuring resistance element C, the heating resistance elements D and E, and the pads 7 to 16 of the second embodiment in place of Needless to say. The electric circuit in this case is shown in FIG.
As shown in. In addition, the elements A, B, C, A ′, B ′ in the first to third embodiments of the present invention,
It is preferable that D and E are all formed of a platinum thin film or the like, but not limited to this.
【００４７】[0047]
【発明の効果】本発明によれば、第１の測温抵抗エレメ
ントと第２の測温抵抗エレメントとの平均の温度（第
１、第２の測温抵抗エレメントで検出される温度の平均
値）が周囲温度よりも常に一定温度高くなるよう第１の
測温抵抗エレメントと第２の測温抵抗エレメントとに印
加する電圧を制御するので、流速が増加しても、感度の
低下が少なくなる。その結果、低速から高速までの広い
範囲の流速の測定が可能となる。また、本発明では、第
１、第２の測温抵抗エレメントの温度を一定にすること
ができるため、従来よりも応答速度を速くすることがで
きる。According to the present invention, the average temperature of the first temperature measuring resistance element and the second temperature measuring resistance element (the average value of the temperatures detected by the first and second temperature measuring resistance elements). ) Controls the voltage applied to the first temperature measuring resistance element and the second temperature measuring resistance element so that the temperature is always higher than the ambient temperature by a constant temperature. Therefore, even if the flow velocity increases, the decrease in sensitivity is reduced. . As a result, it is possible to measure the flow velocity in a wide range from low speed to high speed. Further, in the present invention, since the temperatures of the first and second temperature measuring resistance elements can be made constant, the response speed can be made faster than in the past.
【００４８】また、出力回路を、第３の直列回路と差分
増幅器とから構成することにより、流体の流速に応じた
値を取り出すことができる。Further, by configuring the output circuit with the third series circuit and the differential amplifier, it is possible to take out a value according to the flow velocity of the fluid.
【００４９】また、第１の直列回路と第３の直列回路と
を接続する少なくとも１つのボルテージフォロアを設け
ることにより、ブリッジ回路内を流れる電流が第４の抵
抗と第５の抵抗に流出しないようにすることができる。Further, by providing at least one voltage follower for connecting the first series circuit and the third series circuit, the current flowing in the bridge circuit is prevented from flowing out to the fourth resistance and the fifth resistance. Can be
【図１】 本発明の第１の実施の形態となる流速センサ
の平面図及び断面図である。FIG. 1 is a plan view and a sectional view of a flow velocity sensor according to a first embodiment of the present invention.
【図２】 図１の流速センサの電気回路図である。FIG. 2 is an electric circuit diagram of the flow velocity sensor shown in FIG.
【図３】 本発明の第２の実施の形態となる流速センサ
の平面図である。FIG. 3 is a plan view of a flow velocity sensor according to a second embodiment of the present invention.
【図４】 図３の流速センサの電気回路図である。4 is an electric circuit diagram of the flow velocity sensor of FIG.
【図５】 本発明の第３の実施の形態となる流速センサ
の断面図である。FIG. 5 is a sectional view of a flow velocity sensor according to a third embodiment of the present invention.
【図６】 従来の流速センサの電気回路図である。FIG. 6 is an electric circuit diagram of a conventional flow velocity sensor.
１、３２…基台、２…空隙部、３…薄膜層、４ａ、４
ｂ、５…スリット、６ａ、６ｂ…配設部、７〜１６…パ
ッド、２１、２１ａ…ブリッジ回路、２２…差動増幅回
路、２３…出力回路、３１…流路形成部材、３３…薄肉
部（ダイアフラム部）、３４…電気絶縁膜、Ａ、Ｂ、
Ａ’、Ｂ’…測温抵抗エレメント、Ｃ…周囲温度測温抵
抗エレメント、Ｄ、Ｅ…発熱抵抗エレメント、Ａ１〜Ａ
４…演算増幅器、Ｒ１〜Ｒ３、Ｒ５、Ｒ６…抵抗。1, 32 ... Base, 2 ... Void, 3 ... Thin film layer, 4a, 4
b, 5 ... Slits, 6a, 6b ... Arrangement part, 7-16 ... Pads, 21, 21a ... Bridge circuit, 22 ... Differential amplifier circuit, 23 ... Output circuit, 31 ... Flow path forming member, 33 ... Thin part (Diaphragm portion), 34 ... Electrical insulating film, A, B,
A ', B' ... temperature measurement resistance element, C ... ambient temperature temperature measurement resistance element, D, E ... heat generation resistance element, A1-A
4 ... Operational amplifier, R1 to R3, R5, R6 ... Resistors.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 中野 正志 東京都渋谷区渋谷２丁目12番19号 株式会 社山武内 Ｆターム(参考） 2F035 EA04 EA05 EA08 EA09 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Masashi Nakano 2-12-19 Shibuya, Shibuya-ku, Tokyo Stock market Takeyama F term (reference) 2F035 EA04 EA05 EA08 EA09
Claims (4)
体と温度センサとにより、その流体の流れに起因する熱
移動を求めることによって流体の流速を測定する流速セ
ンサにおいて、 前記発熱体および温度センサを共用する第１の測温抵抗
エレメントおよび第２の測温抵抗エレメントを直列に接
続し、この第１および第２の測温抵抗エレメントに流さ
れる電流をそれらの平均温度が周囲温度より常に一定温
度だけ高くなるように制御する制御回路を有し、前記第
１および第２の測温抵抗エレメントの温度差に基づいて
流速を求めるようにしたことを特徴とする流速センサ。1. A flow velocity sensor for measuring a flow velocity of a fluid by determining heat transfer caused by the flow of the fluid by a heating element and a temperature sensor which are arranged side by side in the flow direction of the fluid, wherein the heating element and the temperature. A first resistance temperature element and a second resistance temperature element that share a sensor are connected in series, and the currents flowing through the first resistance resistance element and the second resistance temperature element are such that their average temperature is always higher than the ambient temperature. A flow velocity sensor having a control circuit for controlling the temperature to increase by a constant temperature, and determining the flow velocity based on the temperature difference between the first and second temperature measuring resistance elements.
体と温度センサとにより、その流体の流れに起因する熱
移動を求めることによって流体の流速を測定する流速セ
ンサにおいて、 前記温度センサである第１の測温抵抗エレメントおよび
第２の測温抵抗エレメントを直列に接続すると共に、こ
れら各測温抵抗エレメントのそれぞれの近傍に前記発熱
体を配置し、前記第１および第２の測温抵抗エレメント
の平均温度が周囲温度より常に一定温度だけ高くなるよ
うに前記発熱体への電流を制御する制御回路を有し、前
記第１および第２の測温抵抗エレメントの温度差に基づ
いて流速を求めるようにしたことを特徴とする流速セン
サ。2. A flow velocity sensor for measuring a flow velocity of a fluid by determining heat transfer caused by the flow of the fluid by a heating element and a temperature sensor which are arranged side by side in the flow direction of the fluid, wherein the temperature sensor. A first temperature measuring resistance element and a second temperature measuring resistance element are connected in series, and the heating element is arranged in the vicinity of each of the temperature measuring resistance elements. A control circuit is provided for controlling the current to the heating element so that the average temperature of the element is always higher than the ambient temperature by a constant temperature, and the flow velocity is determined based on the temperature difference between the first and second temperature measuring resistance elements. A flow velocity sensor characterized by being obtained.
いて、 前記直列に接続された第１および第２の測温抵抗エレメ
ントとを一辺とするブリッジ回路を構成し、この一辺以
外の他の一辺に流体の流れに影響されない周囲温度を測
定する周囲温度センサを含ませ、前記ブリッジ回路の各
中点の電圧差を一定にするように前記発熱体に流す電流
を制御する差動増幅回路を設けたことを特徴とする流速
センサ。3. The flow velocity sensor according to claim 1, wherein a bridge circuit having one side of the first and second temperature measuring resistance elements connected in series is formed, and one side other than the one side is formed. Includes an ambient temperature sensor that measures an ambient temperature that is not affected by the flow of fluid, and provides a differential amplifier circuit that controls a current flowing through the heating element so that the voltage difference at each midpoint of the bridge circuit becomes constant. A flow velocity sensor characterized in that
の流速センサにおいて、 前記直列に接続された第１および第２の測温抵抗エレメ
ントの両端電圧を少なくとも１つのボルテージフォロア
回路で受け、前記両端電圧の分圧と前記第１および第２
の測温抵抗エレメントの接続点の電圧とを比較して流速
を求めるようにしたことを特徴とする流速センサ。4. The flow velocity sensor according to claim 1, wherein at least one voltage follower circuit receives the voltage across the first and second temperature measuring resistance elements connected in series. , The partial voltage of the both-end voltage and the first and second
The flow velocity sensor is characterized in that the flow velocity is obtained by comparing with the voltage at the connection point of the temperature measuring resistance element.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002130507A JP3802443B2 (en) | 2002-05-02 | 2002-05-02 | Flow rate sensor |
| CNB038099942A CN100405066C (en) | 2002-05-02 | 2003-04-28 | Flow velocity sensor |
| PCT/JP2003/005473 WO2003093838A1 (en) | 2002-05-02 | 2003-04-28 | Flow velocity sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002130507A JP3802443B2 (en) | 2002-05-02 | 2002-05-02 | Flow rate sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2003322658A true JP2003322658A (en) | 2003-11-14 |
| JP3802443B2 JP3802443B2 (en) | 2006-07-26 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002130507A Expired - Fee Related JP3802443B2 (en) | 2002-05-02 | 2002-05-02 | Flow rate sensor |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP3802443B2 (en) |
| CN (1) | CN100405066C (en) |
| WO (1) | WO2003093838A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102082105A (en) * | 2010-12-06 | 2011-06-01 | 东南大学 | Thermal wind sensor based on anodic bonding technology and preparation method thereof |
| CN110307876A (en) * | 2018-03-27 | 2019-10-08 | 阿自倍尔株式会社 | Thermal flow rate sensor device and flow correction method |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2040045B1 (en) | 2007-09-20 | 2016-11-30 | Azbil Corporation | Flow sensor |
| JP6322052B2 (en) * | 2013-10-28 | 2018-05-09 | 日本電産サンキョー株式会社 | Sensor device |
| KR101581134B1 (en) * | 2013-10-28 | 2015-12-29 | 니혼 덴산 산쿄 가부시키가이샤 | Sensor device |
| DE112017000359T5 (en) * | 2016-01-13 | 2018-10-04 | Analog Devices Global | Air flow sensor for fan-cooled systems |
| CN107228692A (en) * | 2017-06-30 | 2017-10-03 | 深圳龙电电气股份有限公司 | The metering method and its device of a kind of water flow |
| CN107328449B (en) * | 2017-07-06 | 2019-08-30 | 中国科学院上海微系统与信息技术研究所 | A kind of thermoelectric pile formula gas flow sensor and preparation method thereof |
| CN107345826B (en) * | 2017-07-06 | 2020-12-18 | 中国科学院上海微系统与信息技术研究所 | Thermal gas flow sensor and preparation method thereof |
| JP6867909B2 (en) * | 2017-08-02 | 2021-05-12 | アズビル株式会社 | Thermal flow meter |
| CN110945364B (en) * | 2017-08-05 | 2021-08-03 | 株式会社村田制作所 | Wind speed measuring device and wind speed measuring device |
| CN109211342B (en) * | 2018-09-05 | 2020-03-20 | 四方光电股份有限公司 | Airflow flowmeter, MEMS silicon-based temperature-sensitive chip and preparation method thereof |
| CN111220224B (en) * | 2018-11-26 | 2021-07-13 | 苏州原位芯片科技有限责任公司 | MEMS flow sensor chip |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH073351B2 (en) * | 1987-02-25 | 1995-01-18 | 富士電機株式会社 | Mass flow meter |
| JPH0625684B2 (en) * | 1989-03-31 | 1994-04-06 | 山武ハネウエル株式会社 | Fluid flow rate detection sensor |
| DE4342481C2 (en) * | 1993-12-13 | 1996-09-05 | Siemens Ag | Method of measuring the intake air mass |
| JP3424974B2 (en) * | 1994-03-02 | 2003-07-07 | 株式会社エステック | Flow sensor |
| JPH11351936A (en) * | 1998-06-05 | 1999-12-24 | Mitsubishi Electric Corp | Thermal flow-rate sensor and thermal flow-rate detection circuit |
| JP3825242B2 (en) * | 2000-10-17 | 2006-09-27 | 株式会社山武 | Flow sensor |
-
2002
- 2002-05-02 JP JP2002130507A patent/JP3802443B2/en not_active Expired - Fee Related
-
2003
- 2003-04-28 WO PCT/JP2003/005473 patent/WO2003093838A1/en active Application Filing
- 2003-04-28 CN CNB038099942A patent/CN100405066C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102082105A (en) * | 2010-12-06 | 2011-06-01 | 东南大学 | Thermal wind sensor based on anodic bonding technology and preparation method thereof |
| CN110307876A (en) * | 2018-03-27 | 2019-10-08 | 阿自倍尔株式会社 | Thermal flow rate sensor device and flow correction method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3802443B2 (en) | 2006-07-26 |
| CN100405066C (en) | 2008-07-23 |
| CN1650175A (en) | 2005-08-03 |
| WO2003093838A1 (en) | 2003-11-13 |
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