JP2016151547A

JP2016151547A - Position detection device

Info

Publication number: JP2016151547A
Application number: JP2015030505A
Authority: JP
Inventors: 徳夫君塚; Tokuo Kimizuka; 有祐和佐; Yusuke Kazusa
Original assignee: Metrol Co Ltd
Current assignee: Metrol Co Ltd
Priority date: 2015-02-19
Filing date: 2015-02-19
Publication date: 2016-08-22

Abstract

PROBLEM TO BE SOLVED: To provide a position detection device that can accurately detect a position of a workpiece even when there are variations in characteristics of sensors detecting pressure of pressurized gas.SOLUTION: A position detection device 1 comprises an offset value storage unit that stores an output value of a first pressure sensor 41 under an atmospheric pressure as a first offset value, and stores an output value of a second pressure sensor 42 under the atmospheric pressure as a second offset value. The position detection device 1 further comprises: a first correction unit that outputs a first correction value having the first offset value subtracted from the output value of the first pressure sensor 41; a second correction unit that outputs a second correction value having the second offset value subtracted from the output value of the second pressure sensor 42; and a position detection unit that, when a difference between the first correction value and the second correction value is smaller than a prescribed threshold, detects that a surface of a workpiece W gets closer to a nozzle 10 within a prescribed distance.SELECTED DRAWING: Figure 1

Description

本発明は、位置検出装置に係り、特に加圧気体を用いて被測定物の位置を検出する非接触式位置検出装置に関するものである。 The present invention relates to a position detection device, and more particularly to a non-contact type position detection device that detects the position of an object to be measured using a pressurized gas.

一般に、加工装置により被加工物を加工する際には被加工物をテーブル上に固定して加工を行うが、加工精度を上げるためには、被加工物の被加工面がテーブルの表面と平行又は垂直となるように被加工物の平面度や真直度を維持する必要がある。しかしながら、この方法では、被加工物ごとに平面度や真直度を調整する必要があるため、加工時間の短い被加工物については稼働率が悪くなってしまい、この方法を適用することができない。 In general, when a workpiece is processed by a processing apparatus, the workpiece is fixed on a table for processing, but in order to increase the processing accuracy, the workpiece surface of the workpiece is parallel to the surface of the table. Alternatively, it is necessary to maintain the flatness and straightness of the workpiece so as to be vertical. However, in this method, since it is necessary to adjust the flatness and straightness for each workpiece, the working rate is deteriorated for a workpiece with a short machining time, and this method cannot be applied.

加工時間の短い被加工物にも対応すべく、油圧チャックなどを用いて被加工物の着脱を容易にするとともに、被加工物の基準面又は基準位置が加工装置に対して適切な位置となるように被加工物の位置を調整する方法も知られている。この被加工物の基準面や基準位置は、被加工物がチャックされる部分とは異なる部分に設定されることが多いため、被加工物の基準面や基準位置を高精度で検出し、適切な位置に被加工物を配置する必要がある。 In order to handle workpieces with a short machining time, the workpiece can be easily attached and detached using a hydraulic chuck or the like, and the reference surface or reference position of the workpiece is an appropriate position with respect to the processing apparatus. A method for adjusting the position of the workpiece is also known. Since the workpiece reference plane and reference position are often set to a part different from the part where the workpiece is chucked, the workpiece reference plane and reference position are detected with high accuracy and appropriate. It is necessary to place the work piece at the correct position.

従来から、このような基準面や基準位置の検出のために接触式センサが用いられることが多いが、接触式センサでは、接触式センサの検出点や被加工物の接触点に汚れや異物が付着することによって誤差が生じやすいという問題がある。そこで、最近では、接触式センサに代えて、加圧気体を用いて被加工物の表面の位置を検出する非接触式センサ（位置検出装置）が用いられることが多くなっている（例えば、特許文献１参照）。 Conventionally, contact sensors are often used to detect such reference surfaces and reference positions. However, in contact sensors, dirt and foreign matter are detected at the detection points of the contact sensors and the contact points of the workpiece. There is a problem that an error tends to occur due to adhesion. Therefore, recently, in place of the contact sensor, a non-contact sensor (position detection device) that detects the position of the surface of the workpiece using a pressurized gas is often used (for example, patents). Reference 1).

このような位置検出装置は、加圧気体をオリフィスに通過させた後にこの加圧気体を被加工物に向かって噴出するものである。このとき、被加工物と位置検出装置との間の距離に応じてオリフィスの前後の圧力差が変化するため、圧力センサを用いてこの圧力差を測定することによって、被加工物が位置検出装置から所定の位置にあることを検出できる。しかしながら、オリフィスの前後の圧力を測定する圧力センサの特性には製造上のばらつき（オフセット電圧や出力スパン電圧）があるため、この圧力センサの特性のばらつきに起因して被加工物（被測定物）の位置を精度よく検出することが難しいという問題があった。 Such a position detection device ejects the pressurized gas toward the workpiece after passing the pressurized gas through the orifice. At this time, since the pressure difference before and after the orifice changes according to the distance between the workpiece and the position detection device, the workpiece is detected by measuring the pressure difference using a pressure sensor. It can be detected that it is at a predetermined position. However, there are manufacturing variations (offset voltage and output span voltage) in the characteristics of the pressure sensor that measures the pressure before and after the orifice. ) Is difficult to detect with high accuracy.

特開２００８−８６８５号公報JP 2008-8865 A

本発明は、このような従来技術の問題点に鑑みてなされたもので、加圧気体の圧力を検出するセンサの特性にばらつきがあっても被測定物の位置を精度よく検出することができる位置検出装置を提供することを目的とする。 The present invention has been made in view of such problems of the prior art, and can accurately detect the position of an object to be measured even if the characteristics of a sensor for detecting the pressure of a pressurized gas vary. An object is to provide a position detection device.

本発明の第１の態様によれば、加圧気体の圧力を検出するセンサの特性にばらつきがあっても被測定物の位置を精度よく検出することができる位置検出装置が提供される。この位置検出装置は、被測定物の表面に向けて加圧気体を噴出可能なノズルと、上記ノズルに連通する第１のチャンバと、気体供給源から上記加圧気体が供給される第２のチャンバと、上記第１のチャンバと上記第２のチャンバとを仕切る仕切壁とを備えている。この仕切壁には、上記第１のチャンバと上記第２のチャンバとを連通するオリフィスが形成されている。また、位置検出装置は、上記第１のチャンバ内の圧力を測定する第１の圧力センサと、上記第２のチャンバ内の圧力を測定する第２の圧力センサと、上記第１のチャンバに上記加圧気体を供給していない状態での上記第１の圧力センサの出力値を第１のオフセット値として記憶するとともに、上記第２のチャンバに上記加圧気体を供給していない状態での上記第２の圧力センサの出力値を第２のオフセット値として記憶するオフセット値記憶部と、上記第１の圧力センサの出力値から上記オフセット値記憶部に記憶された上記第１のオフセット値を減算した第１の補正値を出力する第１の補正部と、上記第２の圧力センサの出力値から上記オフセット値記憶部に記憶された上記第２のオフセット値を減算した第２の補正値を出力する第２の補正部と、上記第１の補正部から出力される第１の補正値と上記第２の補正部から出力される第２の補正値との差が所定の閾値よりも小さくなったときに、上記被測定物の表面が上記ノズルから所定の距離未満に近づいたことを検出する位置検出部とを備えている。 According to the first aspect of the present invention, there is provided a position detection device that can accurately detect the position of the object to be measured even if the characteristics of the sensor that detects the pressure of the pressurized gas vary. The position detection device includes a nozzle capable of ejecting a pressurized gas toward the surface of the object to be measured, a first chamber communicating with the nozzle, and a second gas supplied from the gas supply source. A chamber, and a partition wall that partitions the first chamber and the second chamber are provided. The partition wall is formed with an orifice communicating the first chamber and the second chamber. In addition, the position detection device includes a first pressure sensor that measures the pressure in the first chamber, a second pressure sensor that measures the pressure in the second chamber, and the first chamber that has the above-described pressure in the first chamber. The output value of the first pressure sensor when no pressurized gas is supplied is stored as a first offset value, and the pressurized gas is not supplied to the second chamber. An offset value storage unit that stores the output value of the second pressure sensor as a second offset value, and the first offset value stored in the offset value storage unit is subtracted from the output value of the first pressure sensor. A first correction unit that outputs the first correction value, and a second correction value obtained by subtracting the second offset value stored in the offset value storage unit from the output value of the second pressure sensor. Second complement to output And when the difference between the first correction value output from the first correction unit and the second correction value output from the second correction unit is smaller than a predetermined threshold value, A position detection unit that detects that the surface of the object to be measured has approached the nozzle from less than a predetermined distance.

このように、本発明によれば、被測定物の表面の位置の検出にあたって、加圧気体を供給していない状態での第１の圧力センサの出力値（第１のオフセット値）を第１の圧力センサの出力値から減算した第１の補正値と、加圧気体を供給していない状態での第２の圧力センサの出力値（第２のオフセット値）を第２の圧力センサの出力値から減算した第２の補正値とを用いているため、第１の圧力センサと第２の圧力センサのオフセット電圧による影響を受けることなく、被測定物の位置を検出することができる。したがって、加圧気体の圧力を検出するセンサの特性にばらつきがあっても、精度よく被測定物の位置を検出することができる。 As described above, according to the present invention, in detecting the position of the surface of the object to be measured, the output value (first offset value) of the first pressure sensor in the state where the pressurized gas is not supplied is the first. The first correction value subtracted from the output value of the pressure sensor and the output value (second offset value) of the second pressure sensor when no pressurized gas is supplied are output from the second pressure sensor. Since the second correction value subtracted from the value is used, the position of the object to be measured can be detected without being affected by the offset voltages of the first pressure sensor and the second pressure sensor. Therefore, the position of the object to be measured can be accurately detected even if the characteristics of the sensor that detects the pressure of the pressurized gas vary.

本発明の第２の態様によれば、加圧気体の圧力を検出するセンサの特性にばらつきがあっても被測定物の位置を精度よく検出することができる位置検出装置が提供される。この位置検出装置は、被測定物の表面に向けて加圧気体を噴出可能なノズルと、上記ノズルに連通する第１のチャンバと、気体供給源から上記加圧気体が供給される第２のチャンバと、上記第１のチャンバと上記第２のチャンバとを仕切る仕切壁とを備えている。この仕切壁には、上記第１のチャンバと上記第２のチャンバとを連通するオリフィスが形成されている。また、位置検出装置は、上記第１のチャンバ内の圧力を測定する第１の圧力センサと、上記第２のチャンバ内の圧力を測定する第２の圧力センサと、上記第１の圧力センサの実際の出力−圧力特性の傾きと、上記第１の圧力センサの理想的な出力−圧力特性の傾きと、上記第２の圧力センサの実際の出力−圧力特性の傾きと、上記第２の圧力センサの理想的な出力−圧力特性の傾きとを記憶する傾き記憶部と、上記傾き記憶部に記憶された上記第１の圧力センサの理想的な出力−圧力特性の傾きに対する上記第１の圧力センサの実際の出力−圧力特性の傾きの比を上記第１の圧力センサの出力値に乗算した第３の補正値を出力する第３の補正部と、上記傾き記憶部に記憶された上記第２の圧力センサの理想的な出力−圧力特性の傾きに対する上記第２の圧力センサの実際の出力−圧力特性の傾きの比を上記第２の圧力センサの出力値に乗算した第４の補正値を出力する第４の補正部と、上記第３の補正値と上記第４の補正値との差が所定の閾値よりも小さくなったときに、上記被測定物の表面が上記ノズルから所定の距離未満に近づいたことを検出する位置検出部とを備えている。 According to the second aspect of the present invention, there is provided a position detection device capable of accurately detecting the position of the object to be measured even if the characteristics of the sensor for detecting the pressure of the pressurized gas vary. The position detection device includes a nozzle capable of ejecting a pressurized gas toward the surface of the object to be measured, a first chamber communicating with the nozzle, and a second gas supplied from the gas supply source. A chamber, and a partition wall that partitions the first chamber and the second chamber are provided. The partition wall is formed with an orifice communicating the first chamber and the second chamber. In addition, the position detection device includes a first pressure sensor that measures the pressure in the first chamber, a second pressure sensor that measures the pressure in the second chamber, and the first pressure sensor. The slope of the actual output-pressure characteristic, the slope of the ideal output-pressure characteristic of the first pressure sensor, the slope of the actual output-pressure characteristic of the second pressure sensor, and the second pressure An inclination storage unit for storing an ideal output-pressure characteristic inclination of the sensor, and the first pressure with respect to an ideal output-pressure characteristic inclination of the first pressure sensor stored in the inclination storage unit. A third correction unit for outputting a third correction value obtained by multiplying the output value of the first pressure sensor by the ratio of the actual output-pressure characteristics of the sensor to the output value of the first pressure sensor; and the third correction unit stored in the inclination storage unit 2 for the ideal output-pressure characteristic slope of the pressure sensor A fourth correction unit that outputs a fourth correction value obtained by multiplying an output value of the second pressure sensor by an actual output-pressure characteristic slope ratio of the second pressure sensor; and the third correction. A position detection unit that detects that the surface of the object to be measured has approached less than a predetermined distance from the nozzle when the difference between the value and the fourth correction value becomes smaller than a predetermined threshold value. ing.

このように、本発明によれば、被測定物の表面の位置の検出にあたって、第１の圧力センサの理想的な出力−圧力特性の傾きに対する第１の圧力センサの実際の出力−圧力特性の傾きを第１の圧力センサの出力値に乗算した第３の補正値と、第２の圧力センサの理想的な出力−圧力特性の傾きに対する第２の圧力センサの実際の出力−圧力特性の傾きを第２の圧力センサの出力値に乗算した第４の補正値とを用いているため、第１の圧力センサと第２の圧力センサのスパン電圧による影響を受けることなく、被測定物の位置を検出することができる。したがって、加圧気体の圧力を検出するセンサの特性にばらつきがあっても、精度よく被測定物の位置を検出することができる。 Thus, according to the present invention, in detecting the position of the surface of the object to be measured, the actual output-pressure characteristic of the first pressure sensor with respect to the slope of the ideal output-pressure characteristic of the first pressure sensor The third correction value obtained by multiplying the output value of the first pressure sensor by the inclination, and the actual output-pressure characteristic inclination of the second pressure sensor with respect to the ideal output-pressure characteristic inclination of the second pressure sensor. Since the fourth correction value obtained by multiplying the output value of the second pressure sensor is used, the position of the object to be measured is not affected by the span voltage of the first pressure sensor and the second pressure sensor. Can be detected. Therefore, the position of the object to be measured can be accurately detected even if the characteristics of the sensor that detects the pressure of the pressurized gas vary.

本発明の第３の態様によれば、加圧気体の圧力を検出するセンサの特性にばらつきがあっても被測定物の位置を精度よく検出することができる位置検出装置が提供される。この位置検出装置は、被測定物の表面に向けて加圧気体を噴出可能なノズルと、上記ノズルに連通する第１のチャンバと、気体供給源から上記加圧気体が供給される第２のチャンバと、上記第１のチャンバと上記第２のチャンバとを仕切る仕切壁とを備えている。この仕切壁には、上記第１のチャンバと上記第２のチャンバとを連通するオリフィスが形成されている。また、位置検出装置は、上記第１のチャンバ内の圧力を測定する第１の圧力センサと、上記第２のチャンバ内の圧力を測定する第２の圧力センサと、上記第１のチャンバに上記加圧気体を供給していない状態での上記第１の圧力センサの出力値を第１のオフセット値として記憶するとともに、上記第２のチャンバに上記加圧気体を供給していない状態での上記第２の圧力センサの出力値を第２のオフセット値として記憶するオフセット値記憶部と、上記第１の圧力センサの実際の出力−圧力特性の傾きと、上記第１の圧力センサの理想的な出力−圧力特性の傾きと、上記第２の圧力センサの実際の出力−圧力特性の傾きと、上記第２の圧力センサの理想的な出力−圧力特性の傾きとを記憶する傾き記憶部と、入力値から上記オフセット値記憶部に記憶された上記第１のオフセット値を減算した第１の補正値を出力する第１の補正部と、入力値から上記オフセット値記憶部に記憶された上記第２のオフセット値を減算した第２の補正値を出力する第２の補正部と、上記傾き記憶部に記憶された上記第１の圧力センサの理想的な出力−圧力特性の傾きに対する上記第１の圧力センサの実際の出力−圧力特性の傾きの比を入力値に乗算した第３の補正値を出力する第３の補正部と、上記傾き記憶部に記憶された上記第２の圧力センサの理想的な出力−圧力特性の傾きに対する上記第２の圧力センサの実際の出力−圧力特性の傾きの比を入力値に乗算した第４の補正値を出力する第４の補正部と、上記第１の圧力センサの出力値を上記第１の補正部及び上記第３の補正部の一方に入力して得られる出力値を上記第１の補正部及び上記第３の補正部の他方に入力して得られる出力値と、上記第２の圧力センサの出力値を上記第２の補正部及び上記第４の補正部の一方に入力して得られる出力値を上記第２の補正部及び上記第４の補正部の他方に入力して得られる出力値との差が所定の閾値よりも小さくなったときに、上記被測定物の表面が上記ノズルから所定の距離未満に近づいたことを検出する位置検出部とを備えている。 According to the third aspect of the present invention, there is provided a position detection device that can accurately detect the position of the object to be measured even if the characteristics of the sensor that detects the pressure of the pressurized gas vary. The position detection device includes a nozzle capable of ejecting a pressurized gas toward the surface of the object to be measured, a first chamber communicating with the nozzle, and a second gas supplied from the gas supply source. A chamber, and a partition wall that partitions the first chamber and the second chamber are provided. The partition wall is formed with an orifice communicating the first chamber and the second chamber. In addition, the position detection device includes a first pressure sensor that measures the pressure in the first chamber, a second pressure sensor that measures the pressure in the second chamber, and the first chamber that has the above-described pressure in the first chamber. The output value of the first pressure sensor when no pressurized gas is supplied is stored as a first offset value, and the pressurized gas is not supplied to the second chamber. An offset value storage unit that stores an output value of the second pressure sensor as a second offset value, an inclination of an actual output-pressure characteristic of the first pressure sensor, and an ideal value of the first pressure sensor An inclination storage unit for storing an inclination of an output-pressure characteristic, an inclination of an actual output-pressure characteristic of the second pressure sensor, and an ideal output-pressure characteristic of the second pressure sensor; Store offset value from input value A first correction unit that outputs a first correction value obtained by subtracting the first offset value stored in the first offset value, and a first correction unit that subtracts the second offset value stored in the offset value storage unit from the input value. A second correction unit that outputs a correction value of 2 and an ideal output of the first pressure sensor stored in the inclination storage unit -an actual output of the first pressure sensor with respect to a gradient of the pressure characteristic- A third correction unit that outputs a third correction value obtained by multiplying an input value by a slope ratio of the pressure characteristic; and an ideal output-pressure characteristic of the second pressure sensor stored in the slope storage unit. A fourth correction unit that outputs a fourth correction value obtained by multiplying an input value by a ratio of an actual output-pressure characteristic inclination of the second pressure sensor to an inclination; and an output value of the first pressure sensor. Obtained by input to one of the first correction unit and the third correction unit Output value obtained by inputting the output value to the other of the first correction unit and the third correction unit, and the output value of the second pressure sensor as the second correction unit and the fourth correction value. When the difference between the output value obtained by inputting one of the correction units to the other of the second correction unit and the fourth correction unit is smaller than a predetermined threshold value And a position detection unit that detects that the surface of the object to be measured has approached a distance less than a predetermined distance from the nozzle.

また、上記位置検出装置は、上記第２の圧力センサの出力値が異常な範囲にある場合に異常信号を出力する異常検出部をさらに備えていることが好ましい。このような異常信号が出力された場合に、位置検出部の検出結果を非表示にしたり、位置検出部の検出結果が正しくないものであることを表示したりすることによって、例えば、位置検出装置によって被測定物の良品の判断を行う場合などに、圧力変動に起因して不良品が良品として誤検出されてしまうことを防止することができる。 The position detection device preferably further includes an abnormality detection unit that outputs an abnormality signal when the output value of the second pressure sensor is in an abnormal range. When such an abnormal signal is output, the detection result of the position detection unit is hidden or the fact that the detection result of the position detection unit is incorrect is displayed, for example. Thus, it is possible to prevent a defective product from being erroneously detected as a non-defective product due to pressure fluctuations, for example, when a non-defective product is measured.

本発明の第１の態様及び第３の態様によれば、被測定物の表面の位置の検出にあたって、第１のオフセット値を第１の圧力センサの出力値から減算した第１の補正値と、第２のオフセット値を第２の圧力センサの出力値から減算した第２の補正値とを用いているため、第１の圧力センサと第２の圧力センサのオフセット電圧による影響を受けることなく、被測定物の位置を検出することができる。したがって、加圧気体の圧力を検出するセンサの特性にばらつきがあっても、精度よく被測定物の位置を検出することができる。 According to the first aspect and the third aspect of the present invention, the first correction value obtained by subtracting the first offset value from the output value of the first pressure sensor in detecting the position of the surface of the object to be measured; Since the second correction value obtained by subtracting the second offset value from the output value of the second pressure sensor is used, the second offset value is not affected by the offset voltage of the first pressure sensor and the second pressure sensor. The position of the object to be measured can be detected. Therefore, the position of the object to be measured can be accurately detected even if the characteristics of the sensor that detects the pressure of the pressurized gas vary.

本発明の第２の態様及び第３の態様によれば、被測定物の表面の位置の検出にあたって、第１の圧力センサの理想的な出力−圧力特性の傾きに対する第１の圧力センサの実際の出力−圧力特性の傾きを第１の圧力センサの出力値に乗算した第３の補正値と、第２の圧力センサの理想的な出力−圧力特性の傾きに対する第２の圧力センサの実際の出力−圧力特性の傾きを第２の圧力センサの出力値に乗算した第４の補正値とを用いているため、第１の圧力センサと第２の圧力センサのスパン電圧による影響を受けることなく、被測定物の位置を検出することができる。したがって、加圧気体の圧力を検出するセンサの特性にばらつきがあっても、精度よく被測定物の位置を検出することができる。 According to the second aspect and the third aspect of the present invention, in detecting the position of the surface of the object to be measured, the actual first pressure sensor with respect to the slope of the ideal output-pressure characteristic of the first pressure sensor. The third correction value obtained by multiplying the slope of the output-pressure characteristic by the output value of the first pressure sensor, and the actual value of the second pressure sensor relative to the ideal slope of the output-pressure characteristic of the second pressure sensor. Since the fourth correction value obtained by multiplying the slope of the output-pressure characteristic by the output value of the second pressure sensor is used, it is not affected by the span voltage of the first pressure sensor and the second pressure sensor. The position of the object to be measured can be detected. Therefore, the position of the object to be measured can be accurately detected even if the characteristics of the sensor that detects the pressure of the pressurized gas vary.

本発明の第１の実施形態における位置検出装置を示す図である。It is a figure which shows the position detection apparatus in the 1st Embodiment of this invention. 図１に示す位置検出装置の第１のチャンバ内の圧力とノズルから被測定物の表面までの距離との関係を模式的に示すグラフである。It is a graph which shows typically the relationship between the pressure in the 1st chamber of the position detection apparatus shown in FIG. 1, and the distance from the nozzle to the surface of a to-be-measured object. 図１に示す位置検出装置の処理部の構成の一例を示すブロック図である。It is a block diagram which shows an example of a structure of the process part of the position detection apparatus shown in FIG. 図２に示す処理部における処理を説明するためのグラフである。It is a graph for demonstrating the process in the process part shown in FIG. 本発明の第２の実施形態における位置検出装置の処理部の構成の一例を示すブロック図である。It is a block diagram which shows an example of a structure of the process part of the position detection apparatus in the 2nd Embodiment of this invention. 図５に示す処理部における処理を説明するためのグラフである。It is a graph for demonstrating the process in the process part shown in FIG.

以下、本発明に係る位置検出装置の実施形態について図１から図４を参照して詳細に説明する。なお、図１から図４において、同一又は相当する構成要素には、同一の符号を付して重複した説明を省略する。 Hereinafter, embodiments of a position detection device according to the present invention will be described in detail with reference to FIGS. 1 to 4. 1 to 4, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

図１は、本発明の第１の実施形態における位置検出装置１の構成を模式的に示す図である。図１に示すように、本実施形態における位置検出装置１は、被測定物Ｗの表面Ｓに向けて加圧気体を噴出可能なノズル１０と、ノズル１０に連通する第１のチャンバ１１と、気体供給源２０からレギュレータ２２を介して加圧気体が供給される第２のチャンバ１２と、第１のチャンバ１１と第２のチャンバ１２とを仕切る仕切壁３０と、第１のチャンバ１１内の圧力を測定する第１の圧力センサ４１と、第２のチャンバ１２内の圧力を測定する第２の圧力センサ４２とを備えている。 FIG. 1 is a diagram schematically showing a configuration of a position detection device 1 according to the first embodiment of the present invention. As shown in FIG. 1, the position detection device 1 in the present embodiment includes a nozzle 10 that can eject pressurized gas toward the surface S of the workpiece W, a first chamber 11 that communicates with the nozzle 10, A second chamber 12 to which a pressurized gas is supplied from a gas supply source 20 via a regulator 22; a partition wall 30 that partitions the first chamber 11 and the second chamber 12; A first pressure sensor 41 that measures the pressure and a second pressure sensor 42 that measures the pressure in the second chamber 12 are provided.

仕切壁３０には、仕切壁３０を貫通するオリフィス３２が形成されており、このオリフィス３２によって第１のチャンバ１１と第２のチャンバ１２とが連通される。第１の圧力センサ４１は、第１のチャンバ１１に連通する経路４１Ａを有しており、例えば、第１のチャンバ１１内の圧力を受けるダイアフラムの変形を検出することにより第１のチャンバ１１内の圧力を測定するものである。同様に、第２の圧力センサ４２は、第２のチャンバ１２に連通する経路４２Ａを有しており、例えば、第２のチャンバ１２内の圧力を受けるダイアフラムの変形を検出することにより第２のチャンバ１２内の圧力を測定するものである。このような圧力センサ４１，４２としては既知の種々の圧力センサを用いることができる。 In the partition wall 30, an orifice 32 penetrating the partition wall 30 is formed, and the first chamber 11 and the second chamber 12 are communicated with each other by the orifice 32. The first pressure sensor 41 has a path 41 </ b> A communicating with the first chamber 11. For example, the first pressure sensor 41 detects the deformation of the diaphragm that receives the pressure in the first chamber 11, thereby detecting the inside of the first chamber 11. The pressure is measured. Similarly, the second pressure sensor 42 has a path 42 </ b> A communicating with the second chamber 12. For example, the second pressure sensor 42 detects the deformation of the diaphragm that receives the pressure in the second chamber 12. The pressure in the chamber 12 is measured. As such pressure sensors 41 and 42, various known pressure sensors can be used.

気体供給源２０は、加圧された気体を外部に供給できるように構成されている。この気体供給源２０内の加圧気体がレギュレータ２２により所定の圧力（以下、供給圧力という）Ｐ₀に調整されて第２のチャンバ１２に供給される。第２のチャンバ１２に供給された加圧気体は、仕切壁３０のオリフィス３２を通過して第１のチャンバ１１にも流入し、ノズル１０から被測定物Ｗの表面Ｓに向けて噴出される。 The gas supply source 20 is configured to supply pressurized gas to the outside. The pressurized gas in the gas supply source 20 is adjusted to a predetermined pressure (hereinafter referred to as supply pressure) P ₀ by the regulator 22 and supplied to the second chamber 12. The pressurized gas supplied to the second chamber 12 passes through the orifice 32 of the partition wall 30 and flows into the first chamber 11 and is ejected from the nozzle 10 toward the surface S of the object W to be measured. .

ここで、第１のチャンバ１１内の圧力をＰ₁、ノズル１０から被測定物Ｗの表面Ｓまでの距離をＤとすると、Ｐ₁とＤの関係は図２に示すようになる。すなわち、被測定物Ｗがノズル１０からより遠くに位置すればするほど（Ｄが大きくなればなるほど）、加圧流体は抵抗を受けることなくノズル１０から噴出されることとなるので、第１のチャンバ１１の圧力Ｐ₁は供給圧力Ｐ₀から下がり大気圧に近づいていく。一方、被測定物Ｗがノズル１０のより近くに位置すればするほど（Ｄが小さくなればなるほど）、ノズル１０から噴出される加圧気体が被測定物Ｗの表面Ｓで抵抗を受けるため、第１のチャンバ１１の圧力Ｐ₁は加圧気体の供給圧力Ｐ₀からあまり下がらずに維持される。したがって、第１の圧力センサ４１で測定される圧力Ｐ₁の変化を測定することにより被測定物Ｗの表面Ｓがノズル１０に近づいたことを検出することができる。 Here, if the pressure in the first chamber 11 is P ₁ and the distance from the nozzle 10 to the surface S of the workpiece W is D, the relationship between P ₁ and D is as shown in FIG. That is, as the object to be measured W is located farther from the nozzle 10 (as D becomes larger), the pressurized fluid is ejected from the nozzle 10 without receiving resistance. The pressure P _{1 in the} chamber 11 decreases from the supply pressure P ₀ and approaches the atmospheric pressure. On the other hand, the closer the object to be measured W is located closer to the nozzle 10 (the smaller the D becomes), the more the pressurized gas ejected from the nozzle 10 receives resistance at the surface S of the object to be measured W. The pressure P _{1 in} the first chamber 11 is maintained without much lowering from the pressurized gas supply pressure P ₀ . Therefore, it is possible to detect that the surface S of the workpiece W has approached the nozzle 10 by measuring the change in the pressure P ₁ measured by the first pressure sensor 41.

この場合において、第１のチャンバ１１の圧力Ｐ₁は第２のチャンバ１２の圧力Ｐ₂に依存しているため、第１のチャンバ１１の圧力Ｐ₁のみを測定していたのでは安定的な測定結果とはならない。このため、本実施形態では、第１のチャンバ１１の圧力Ｐ₁に加えて第２のチャンバ１２の圧力Ｐ₂も測定している。そして、第１のチャンバ１１の圧力Ｐ₁と第２のチャンバ１２の圧力Ｐ₂との差Ｐ₂−Ｐ₁を算出し、この圧力差Ｐ₂−Ｐ₁が小さくなったことを検出することによって被測定物Ｗの表面Ｓがノズル１０から所定の距離未満に近づいたことを検出している。このような圧力差Ｐ₂−Ｐ₁を用いることにより、第２のチャンバ１２の圧力Ｐ₂の変動の影響がキャンセルされるので精度のよい測定が可能となる。 In this case, since the pressure P ₁ of the _first chamber 11 depends on the pressure P ₂ of the second chamber 12, it is stable if only the pressure P ₁ of the first chamber 11 is measured. It is not a measurement result. Therefore, in the present embodiment is also measured pressure P ₂ of the second chamber 12 in addition to the pressure P ₁ of the first chamber 11. Then, it is detected that the pressure P ₁ of the first chamber 11 second calculates a difference P ₂ -P ₁ and the pressure P ₂ of the chamber 12, the pressure difference P ₂ -P ₁ is smaller Thus, it is detected that the surface S of the workpiece W has approached the nozzle 10 less than a predetermined distance. By using such a pressure difference P ₂ −P ₁ , the influence of the fluctuation of the pressure P _{2 in} the _second chamber 12 is canceled, so that accurate measurement is possible.

図１に戻って、位置検出装置１は、第１の圧力センサ４１及び第２の圧力センサ４２の出力をＡ／Ｄ変換するＡ／Ｄコンバータ４３と、Ａ／Ｄ変換後の第１の圧力センサ４１及び第２の圧力センサ４２の出力を処理する処理部５０と、処理部５０における処理結果を出力する出力部６０とを有している。例えば、出力部６０はＬＥＤやディスプレイなどの出力機器から構成される。 Returning to FIG. 1, the position detection device 1 includes an A / D converter 43 that performs A / D conversion on outputs of the first pressure sensor 41 and the second pressure sensor 42, and a first pressure after A / D conversion. It has the process part 50 which processes the output of the sensor 41 and the 2nd pressure sensor 42, and the output part 60 which outputs the process result in the process part 50. For example, the output unit 60 includes an output device such as an LED or a display.

図３は、処理部５０の構成の一例を示すブロック図である。この処理部５０は、例えば記憶装置に記憶されたプログラムとＣＰＵなどから構成されるものであり、プログラムの実行により以下に述べる各機能が実現される。また、図３に示すように、処理部５０は、ＲＡＭやＲＯＭ、フラッシュメモリなどの記憶装置からなるオフセット値記憶部５１を有している。第１の圧力センサ４１や第２の圧力センサ４２の実際の出力−圧力特性は、製造上のばらつきにより、図４に示すように理想的な出力−圧力特性からずれていることがある（オフセット電圧）。本実施形態では、このオフセット電圧に応じて第１の圧力センサ４１の出力値及び第２の圧力センサ４２の出力値を補正して被測定物Ｗの位置の検出を行っている。 FIG. 3 is a block diagram illustrating an example of the configuration of the processing unit 50. The processing unit 50 includes, for example, a program stored in a storage device and a CPU, and each function described below is realized by executing the program. As shown in FIG. 3, the processing unit 50 includes an offset value storage unit 51 including a storage device such as a RAM, a ROM, and a flash memory. The actual output-pressure characteristics of the first pressure sensor 41 and the second pressure sensor 42 may deviate from the ideal output-pressure characteristics as shown in FIG. 4 due to manufacturing variations (offset). Voltage). In this embodiment, the position of the workpiece W is detected by correcting the output value of the first pressure sensor 41 and the output value of the second pressure sensor 42 in accordance with the offset voltage.

具体的には、第１のチャンバ１１に加圧気体を供給していない状態（大気圧下）での第１の圧力センサ４１及び第２の圧力センサ４２の出力値（オフセット電圧）をそれぞれ測定しておき、これらの出力値をオフセット値記憶部５１に記憶しておく。すなわち、オフセット値記憶部５１には、第１のチャンバ１１に加圧気体を供給していない状態（大気圧下）での第１の圧力センサ４１の出力値が第１のオフセット値Ｖ_off1として記憶されており、また、第２のチャンバ１２に加圧気体を供給していない状態（大気圧下）での第２の圧力センサ４２の出力値が第２のオフセット値Ｖ_off2として記憶されている。 Specifically, the output values (offset voltages) of the first pressure sensor 41 and the second pressure sensor 42 in a state where pressurized gas is not supplied to the first chamber 11 (under atmospheric pressure) are measured. In addition, these output values are stored in the offset value storage unit 51. That is, in the offset value storage unit 51, the output value of the first pressure sensor 41 in a state where the pressurized gas is not supplied to the first chamber 11 (under atmospheric pressure) is set as the first offset value V _off1. The output value of the second pressure sensor 42 is stored as the second offset value V _off2 when the pressurized gas is not supplied to the second chamber 12 (under atmospheric pressure). Yes.

また、処理部５０は、第１の圧力センサ４１の出力値Ｖ_out1からオフセット値記憶部５１に記憶された第１のオフセット値Ｖ_off1を減算した第１の補正値Ｖ_c1を出力する第１の補正部５２と、第２の圧力センサ４２の出力値Ｖ_out2からオフセット値記憶部５１に記憶された第２のオフセット値Ｖ_off2を減算した第２の補正値Ｖ_c2を出力する第２の補正部５３と、これらの補正値Ｖ_c1，Ｖ_c2を用いて被測定物Ｗの表面Ｓがノズル１０から所定の距離未満に近づいたことを検出する位置検出部５４とを含んでいる。より具体的には、位置検出部５４は、所定の閾値Ｖ_tを記憶しており、第１の補正部５２から出力される第１の補正値Ｖ_c1と第２の補正部５３から出力される第２の補正値Ｖ_c2との差Ｖ_c2−Ｖ_c1を算出し、この差Ｖ_c2−Ｖ_c1が閾値Ｖ_tよりも小さくなったときに、被測定物Ｗの表面Ｓがノズル１０から所定の距離未満に近づいたものと判断する。 Further, the processing unit 50 outputs a first correction value V _c1 _obtained by subtracting the first offset value V _off1 stored in the offset value storage unit 51 from the output value V _{out1 of} the first pressure sensor 41. And a second correction value V _c2 obtained by subtracting the second offset value V _off2 stored in the offset value storage unit 51 from the output value V _{out2 of} the second pressure sensor 42. The correction part 53 and the position detection part 54 which detects that the surface S of the to-be-measured object W approached less than predetermined distance from the nozzle 10 using these correction value _Vc1 , _Vc2 are included. More specifically, the position detection unit 54 stores a predetermined threshold value V _t, the first correction value V _c1 outputted from the first correction mechanism 52 is outputted from the second correcting unit 53 The difference V _c2 −V _c1 from the second correction value V _c2 is calculated, and when the difference V _c2 −V _c1 becomes smaller than the threshold value V _t , the surface S of the workpiece W is removed from the nozzle 10. It is determined that the vehicle is approaching a predetermined distance.

このように、本実施形態では、被測定物Ｗの位置の検出にあたって、大気圧下での第１の圧力センサ４１の出力値（第１のオフセット値Ｖ_off1）を第１の圧力センサ４１の出力値Ｖ_out1から減算した第１の補正値Ｖ_c1と、大気圧下での第２の圧力センサ４２の出力値（第２のオフセット値Ｖ_off2）を第２の圧力センサ４２の出力値Ｖ_out2から減算した第２の補正値Ｖ_c2とを用いているため、第１の圧力センサ４１と第２の圧力センサ４２のオフセット電圧による影響を受けることなく、被測定物Ｗの位置を検出することができる。したがって、より精度よく被測定物Ｗの位置を検出することができる。 Thus, in the present embodiment, when detecting the position of the workpiece W, the output value (first offset value V _off1 ) of the first pressure sensor 41 under atmospheric pressure is used as the first pressure sensor 41. The first correction value V _c1 subtracted from the output value V _out1 and the output value (second offset value V _off2 ) of the second pressure sensor 42 under atmospheric pressure are the output value V of the second pressure sensor 42. _Since the second correction value V _c2 subtracted from _out2 is used, the position of the workpiece W is detected without being affected by the offset voltage of the first pressure sensor 41 and the second pressure sensor 42. be able to. Accordingly, the position of the workpiece W can be detected with higher accuracy.

ところで、気体供給源２０におけるコンプレッサの供給能力、加圧空気のリップル（コンプレッサからの空気の脈動）、負荷による圧力変動、レギュレータ２２の制御特性などによって、上述した圧力Ｐ₀，Ｐ₁，Ｐ₂は常に変動している。したがって、位置検出装置１の精度はこれらの圧力変動に依存することとなる。本実施形態では、これらの圧力変動による誤検出を防止し、位置検出装置１の精度を向上させている。すなわち、図３に示すように、処理部５０は、第２の圧力センサ４２の出力値Ｖ_out2が異常な範囲にある場合に異常信号を出力する異常検出部５５を含んでいる。第２の圧力センサ４２の出力値Ｖ_out2が異常な範囲にある場合に、この異常検出部５５が出力部６０に異常信号を出力すると、この異常信号を受けた出力部６０は、例えば位置検出部５４による検出結果を非表示にするか、あるいは位置検出部５４による検出結果が正しくないものであることを表示する。これにより位置検出装置１によって被測定物Ｗの良品の判断を行う場合などに、圧力変動に起因して不良品が良品として誤検出されてしまうことが防止される。 By the way, the pressure P ₀ , P ₁ , P ₂ described above is determined by the supply capacity of the compressor in the gas supply source 20, the ripple of pressurized air (pulsation of air from the compressor), the pressure fluctuation due to the load, the control characteristics of the regulator 22, etc. Is constantly fluctuating. Therefore, the accuracy of the position detection device 1 depends on these pressure fluctuations. In the present embodiment, erroneous detection due to these pressure fluctuations is prevented, and the accuracy of the position detection device 1 is improved. That is, as shown in FIG. 3, the processing unit 50 includes an abnormality detection unit 55 that outputs an abnormality signal when the output value V _{out2 of} the second pressure sensor 42 is in an abnormal range. When the output value V _{out2 of} the second pressure sensor 42 is in an abnormal range, when the abnormality detection unit 55 outputs an abnormality signal to the output unit 60, the output unit 60 that has received the abnormality signal performs, for example, position detection. The detection result by the unit 54 is not displayed, or it is displayed that the detection result by the position detection unit 54 is incorrect. This prevents a defective product from being erroneously detected as a non-defective product due to pressure fluctuation when the position detection device 1 determines a non-defective product to be measured.

また、第１の圧力センサ４１や第２の圧力センサ４２の実際の出力−圧力特性は、製造上のばらつきにより、理想的な出力−圧力特性の傾きとは異なる傾きを有する場合がある（スパン電圧）。以下に述べる本発明の第２の実施形態では、上述したオフセット電圧に加えて、このようなスパン電圧に応じて第１の圧力センサ４１の出力値及び第２の圧力センサ４２の出力値を補正して被測定物Ｗの位置の検出を行う。 Further, the actual output-pressure characteristics of the first pressure sensor 41 and the second pressure sensor 42 may have a slope different from the slope of the ideal output-pressure characteristic due to manufacturing variations (span. Voltage). In the second embodiment of the present invention described below, in addition to the offset voltage described above, the output value of the first pressure sensor 41 and the output value of the second pressure sensor 42 are corrected according to such a span voltage. Thus, the position of the workpiece W is detected.

図５は、本発明の第２の実施形態における位置検出装置の処理部１５０の構成の一例を示すブロック図である。図５に示すように、処理部１５０は、上述したオフセット値記憶部５１に加えて、ＲＡＭやＲＯＭ、フラッシュメモリなどの記憶装置からなる傾き記憶部１５１を有している。この傾き記憶部１５１には、第１の圧力センサ４１の実際の出力−圧力特性の傾きＳ_a1と、第１の圧力センサ４１の理想的な出力−圧力特性の傾きＳ_r1と、第２の圧力センサ４２の実際の出力−圧力特性の傾きＳ_a2と、第２の圧力センサ４２の理想的な出力−圧力特性の傾きＳ_r2とが記憶されている。 FIG. 5 is a block diagram showing an example of the configuration of the processing unit 150 of the position detection device according to the second embodiment of the present invention. As illustrated in FIG. 5, the processing unit 150 includes an inclination storage unit 151 including a storage device such as a RAM, a ROM, and a flash memory in addition to the offset value storage unit 51 described above. The inclination storage 151 includes an actual output-pressure characteristic inclination S _a1 of the first pressure sensor 41, an ideal output-pressure characteristic inclination S _{r1 of} the first pressure sensor 41, and a second The actual output-pressure characteristic slope S _a2 of the pressure sensor 42 and the ideal output-pressure characteristic slope S _{r2 of} the second pressure sensor 42 are stored.

第１の圧力センサ４１の実際の出力−圧力特性の傾きＳ_a1は以下のようにして取得し、傾き記憶部１５１に記憶される。まず、第１のチャンバ１１の圧力を既知の圧力Ｐ_ref1にする（図６参照）。この状態で第１の圧力センサ４１の出力値Ｖ_out1を測定する。この出力値Ｖ_out1と圧力Ｐ_ref1との関係により傾きＳ_a1を算出し、これを傾き記憶部１５１に記憶する。図６に示す例では、Ｓ_a1＝（Ｖ_out1−Ｖ_off1）／Ｐ_ref1として算出される。同様にして、第２の圧力センサ４２の実際の出力−圧力特性の傾きＳ_a2も算出され、傾き記憶部１５１に記憶される。 The slope S _a1 of the actual output-pressure characteristic of the first pressure sensor 41 is acquired as follows and stored in the slope storage unit 151. First, the pressure in the first chamber 11 is set to a known pressure _Pref1 (see FIG. 6). In this state, the output value V _out1 of the first pressure sensor 41 is measured. The inclination S _a1 is calculated from the relationship between the output value V _out1 and the pressure P _ref1, and is stored in the inclination storage unit 151. In the example shown in FIG. 6, it is calculated as S _a1 = (V _out1 −V _off1 ) / P _ref1 . Similarly, the slope S _a2 of the actual output-pressure characteristic of the second pressure sensor 42 is also calculated and stored in the slope storage unit 151.

また、処理部１５０は、傾き記憶部１５１に記憶されたＳ_a1，Ｓ_r1を参照して、第１の補正部５２から出力される第１の補正値Ｖ_c1にＳ_a1／Ｓ_r1を乗算した第３の補正値Ｖ_c3を出力する第３の補正部１５２と、傾き記憶部１５１に記憶されたＳ_a2，Ｓ_r2を参照して、第２の補正部５３から出力される第２の補正値Ｖ_c2にＳ_a2／Ｓ_r2を乗算した第４の補正値Ｖ_c4を出力する第４の補正部１５３と、これらの補正値Ｖ_c3，Ｖ_c4を用いて被測定物Ｗの表面Ｓがノズル１０から所定の距離未満に近づいたことを検出する位置検出部１５４とを含んでいる。より具体的には、位置検出部１５４は、所定の閾値Ｖ_tを記憶しており、第３の補正部１５２から出力される第３の補正値Ｖ_c3と第４の補正部１５３から出力される第４の補正値Ｖ_c4との差Ｖ_c4−Ｖ_c3を算出し、この差Ｖ_c4−Ｖ_c3が閾値Ｖ_tよりも小さくなったときに、被測定物Ｗの表面Ｓがノズル１０から所定の距離未満に近づいたものと判断する。 The processing unit 150 refers to S _a1 and S _r1 stored in the inclination storage unit 151 and multiplies the first correction value V _c1 output from the first correction unit 52 by S _a1 / S _r1 . The third correction unit 152 that outputs the third correction value V _c3 and the second correction unit 53 that is output from the second correction unit 53 with reference to S _a2 and S _r2 stored in the inclination storage unit 151. A fourth correction unit 153 that outputs a fourth correction value V _c4 obtained by multiplying the correction value V _c2 by S _a2 / S _r2, and the surface S of the object W to be measured using these correction values V _c3 and V _c4. Includes a position detection unit 154 that detects that the nozzle has approached less than a predetermined distance from the nozzle 10. More specifically, the position detection unit 154 stores a predetermined threshold value V _t, the third correction value V _c3 output from the third correcting unit 152 is output from the fourth corrector 153 The difference V _c4 -V _c3 from the fourth correction value V _c4 is calculated, and when the difference V _c4 -V _c3 becomes smaller than the threshold value V _t , the surface S of the workpiece W is removed from the nozzle 10. It is determined that the vehicle is approaching a predetermined distance.

このように、本実施形態では、被測定物Ｗの位置の検出にあたって、第１の圧力センサ４１の出力値Ｖ_out1から第１のオフセット値Ｖ_off1を減算した第１の補正値Ｖ_c1と、この第１の補正値Ｖ_c1にＳ_a1／Ｓ_r1を乗算した第３の補正値Ｖ_c3と、第２の圧力センサ４２の出力値Ｖ_out2から第２のオフセット値Ｖ_off2を減算した第２の補正値Ｖ_c2と、この第２の補正値Ｖ_c2にＳ_a2／Ｓ_r2を乗算した第４の補正値Ｖ_c4とを用いているため、第１の圧力センサ４１と第２の圧力センサ４２のオフセット電圧やスパン電圧による影響を受けることなく、被測定物Ｗの位置を検出することができる。したがって、より精度よく被測定物Ｗの位置を検出することができる。 Thus, in the present embodiment, in detecting the position of the workpiece W, the first correction value V _c1 _obtained by subtracting the first offset value V _off1 from the output value V _out1 of the first pressure sensor 41; A second correction value V _{c3 obtained} by multiplying the first correction value V _c1 by S _a1 / S _r1 and a second offset value V _off2 subtracted from the output value V _out2 of the second pressure sensor 42. the pressure sensor of the correction value V _c2, to the second correction value V _c2 due to the use of a fourth correction value V _c4 obtained by multiplying the S _a2 / S _r2, a first pressure sensor 41 of the second The position of the workpiece W can be detected without being affected by the offset voltage or span voltage of 42. Accordingly, the position of the workpiece W can be detected with higher accuracy.

図５に示す例では、第１の圧力センサ４１の出力値Ｖ_out1が第１の補正部５２に入力されているが、第１の補正部５２と第３の補正部１５２の順番を入れ替えてもよい。すなわち、第１の圧力センサ４１の出力値Ｖ_out1を第３の補正部１５２に入力し、第３の補正部１５２からの出力値を第１の補正部５２に入力し、第１の補正部５２からの出力値を位置検出部１５４に入力してもよい。また、第２の圧力センサ４２の出力値Ｖ_out2が第２の補正部５３に入力されているが、第２の補正部５３と第４の補正部１５３の順番を入れ替えてもよい。すなわち、第２の圧力センサ４２の出力値Ｖ_out2を第４の補正部１５３に入力し、第４の補正部１５３からの出力値を第２の補正部５３に入力し、第２の補正部５３からの出力値を位置検出部１５４に入力してもよい。 In the example shown in FIG. 5, the output value V _out1 of the first pressure sensor 41 is input to the first correction unit 52, but the order of the first correction unit 52 and the third correction unit 152 is changed. Also good. That is, the output value V _out1 of the first pressure sensor 41 is input to the third correction unit 152, the output value from the third correction unit 152 is input to the first correction unit 52, and the first correction unit The output value from 52 may be input to the position detection unit 154. Further, although the output value V _out2 of the second pressure sensor 42 is input to the second correction unit 53, the order of the second correction unit 53 and the fourth correction unit 153 may be switched. That is, the output value V _out2 of the second pressure sensor 42 is input to the fourth correction unit 153, the output value from the fourth correction unit 153 is input to the second correction unit 53, and the second correction unit 53 The output value from 53 may be input to the position detector 154.

なお、本実施形態では、第１の実施形態で説明した第１の補正部５２及び第２の補正部５３を第３の補正部１５２及び第４の補正部１５３に組み合わせた例について説明したが、第１の補正部５２及び第２の補正部５３を省略することもできる。例えば、第１の補正部５２及び第２の補正部５３を設けることなく、第１の圧力センサ４１の出力値Ｖ_out1にＳ_a1／Ｓ_r1を乗算した補正値と第２の圧力センサ４２の出力値Ｖ_out2にＳ_a2／Ｓ_r2を乗算した補正値とを用いて被測定物Ｗの位置を検出してもよい。 In the present embodiment, an example in which the first correction unit 52 and the second correction unit 53 described in the first embodiment are combined with the third correction unit 152 and the fourth correction unit 153 has been described. The first correction unit 52 and the second correction unit 53 can be omitted. For example, the correction value obtained by multiplying the output value V _out1 of the first pressure sensor 41 by S _a1 / S _r1 and the second pressure sensor 42 without providing the first correction unit 52 and the second correction unit 53. The position of the workpiece W may be detected using a correction value obtained by multiplying the output value V _out2 by S _a2 / S _r2 .

これまで本発明の好ましい実施形態について説明したが、本発明は上述の実施形態に限定されず、その技術的思想の範囲内において種々異なる形態にて実施されてよいことは言うまでもない。 The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and it goes without saying that the present invention may be implemented in various forms within the scope of the technical idea.

１位置検出装置
１０ノズル
１１第１のチャンバ
１２第２のチャンバ
２０気体供給源
２２レギュレータ
３０仕切壁
３２オリフィス
４１第１の圧力センサ
４２第２の圧力センサ
４３Ａ／Ｄコンバータ
５０処理部
５１オフセット値記憶部
５２第１の補正部
５３第２の補正部
５４位置検出部
５５異常検出部
６０出力部
１５０処理部
１５１傾き記憶部
１５２第３の補正部
１５３第４の補正部
１５４位置検出部 DESCRIPTION OF SYMBOLS 1 Position detection apparatus 10 Nozzle 11 1st chamber 12 2nd chamber 20 Gas supply source 22 Regulator 30 Partition wall 32 Orifice 41 1st pressure sensor 42 2nd pressure sensor 43 A / D converter 50 Processing part 51 Offset value Storage unit 52 First correction unit 53 Second correction unit 54 Position detection unit 55 Abnormality detection unit 60 Output unit 150 Processing unit 151 Inclination storage unit 152 Third correction unit 153 Fourth correction unit 154 Position detection unit

Claims

A nozzle capable of injecting pressurized gas toward the surface of the object to be measured;
A first chamber in communication with the nozzle;
A second chamber to which the pressurized gas is supplied from a gas supply source;
A partition wall for partitioning the first chamber and the second chamber, wherein the partition wall is formed with an orifice communicating the first chamber and the second chamber;
A first pressure sensor for measuring the pressure in the first chamber;
A second pressure sensor for measuring the pressure in the second chamber;
The output value of the first pressure sensor when the pressurized gas is not supplied to the first chamber is stored as a first offset value, and the pressurized gas is supplied to the second chamber. An offset value storage unit that stores an output value of the second pressure sensor in a state of not being performed as a second offset value;
A first correction unit that outputs a first correction value obtained by subtracting the first offset value stored in the offset value storage unit from the output value of the first pressure sensor;
A second correction unit that outputs a second correction value obtained by subtracting the second offset value stored in the offset value storage unit from the output value of the second pressure sensor;
A position at which it is detected that the surface of the object to be measured is closer than a predetermined distance from the nozzle when the difference between the first correction value and the second correction value is smaller than a predetermined threshold value. A detection unit;
A position detection device comprising:

A nozzle capable of injecting pressurized gas toward the surface of the object to be measured;
A first chamber in communication with the nozzle;
A second chamber to which the pressurized gas is supplied from a gas supply source;
A partition wall for partitioning the first chamber and the second chamber, wherein the partition wall is formed with an orifice communicating the first chamber and the second chamber;
A first pressure sensor for measuring the pressure in the first chamber;
A second pressure sensor for measuring the pressure in the second chamber;
The slope of the actual output-pressure characteristic of the first pressure sensor, the slope of the ideal output-pressure characteristic of the first pressure sensor, and the slope of the actual output-pressure characteristic of the second pressure sensor An inclination storage unit that stores an ideal output-pressure characteristic inclination of the second pressure sensor;
The ratio of the actual output-pressure characteristic inclination of the first pressure sensor to the ideal output-pressure characteristic inclination of the first pressure sensor stored in the inclination storage unit is determined by the first pressure sensor. A third correction unit that outputs a third correction value multiplied by the output value;
The ratio of the actual output-pressure characteristic inclination of the second pressure sensor to the ideal output-pressure characteristic inclination of the second pressure sensor stored in the inclination storage unit is determined by the second pressure sensor. A fourth correction unit that outputs a fourth correction value multiplied by the output value;
A position at which it is detected that the surface of the object to be measured is closer than a predetermined distance from the nozzle when the difference between the third correction value and the fourth correction value is smaller than a predetermined threshold value. A detection unit;
A position detection device comprising:

A nozzle capable of injecting pressurized gas toward the surface of the object to be measured;
A first chamber in communication with the nozzle;
A second chamber to which the pressurized gas is supplied from a gas supply source;
A partition wall for partitioning the first chamber and the second chamber, wherein the partition wall is formed with an orifice communicating the first chamber and the second chamber;
A first pressure sensor for measuring the pressure in the first chamber;
A second pressure sensor for measuring the pressure in the second chamber;
The output value of the first pressure sensor when the pressurized gas is not supplied to the first chamber is stored as a first offset value, and the pressurized gas is supplied to the second chamber. An offset value storage unit that stores an output value of the second pressure sensor in a state of not being performed as a second offset value;
The slope of the actual output-pressure characteristic of the first pressure sensor, the slope of the ideal output-pressure characteristic of the first pressure sensor, and the slope of the actual output-pressure characteristic of the second pressure sensor An inclination storage unit that stores an ideal output-pressure characteristic inclination of the second pressure sensor;
A first correction unit that outputs a first correction value obtained by subtracting the first offset value stored in the offset value storage unit from an input value;
A second correction unit that outputs a second correction value obtained by subtracting the second offset value stored in the offset value storage unit from an input value;
A third value obtained by multiplying the input value by the ratio of the actual output-pressure characteristic inclination of the first pressure sensor to the ideal output-pressure characteristic inclination of the first pressure sensor stored in the inclination storage unit. A third correction unit that outputs the correction value of
A fourth value obtained by multiplying the input value by the ratio of the actual output-pressure characteristic inclination of the second pressure sensor to the ideal output-pressure characteristic inclination of the second pressure sensor stored in the inclination storage unit. A fourth correction unit that outputs the correction value of
The output value obtained by inputting the output value of the first pressure sensor into one of the first correction unit and the third correction unit is output to the other of the first correction unit and the third correction unit. The output value obtained by inputting the output value obtained by inputting the output value of the second pressure sensor into one of the second correction unit and the fourth correction unit is input to the second correction unit and When the difference between the output value obtained by inputting to the other of the fourth correction units is smaller than a predetermined threshold, the surface of the object to be measured has approached a predetermined distance from the nozzle. A position detection unit to detect;
A position detection device comprising:

4. The position detection device according to claim 1, further comprising an abnormality detection unit that outputs an abnormality signal when an output value of the second pressure sensor is in an abnormal range. 5. .