Abstract: In a flow path forming structure, axial runout of a shaft relative to a central axis generated when the shaft is inserted into the flow path is suppressed. This structure includes a flow path along which a fluid passes, and a shaft body that is inserted into the flow path. An upstream side of the shaft body and an inner circumferential surface of the flow path have a plurality of contact positions at different phases, and a downstream side of the shaft body and an inner circumferential surface of the flow path have a plurality of contact positions at different phases. The fluid flows through gaps between the shaft body and the inner circumferential surface. The contact positions on one of the upstream and downstream sides are at different phases from all of the contact positions on the other one of the upstream and downstream sides.

Abstract: In order to suppress changes in opening level and flow rate associated with the thermal expansion of a resin member caused by a temperature change, a valve device that displaces a valve body by applying drive voltage to an actuator is adapted to include: a position sensor that detects the position of the valve body; a voltage regulator that regulates the drive voltage on the basis of a detected position by the position sensor; and a temperature sensor that detects the temperature of the valve body. In addition, the seating surface of the valve body is adapted to be formed of a resin member, and the voltage regulator is adapted to change the setting value of the drive voltage depending on detected temperature by the temperature sensor.

Abstract: The present invention provides a fluid control valve that improves usability by eliminating misunderstanding of a user. The fluid control valve includes a valve seat, a valve body disposed to be approachable to and separable from the valve seat, an actuator configured to move the valve body in an approaching or separating direction, a positional information detection part configured to detect a value corresponding to a relative position of the valve body with respect to the valve seat, and a position output part configured to set, irrespective of positional information acquired by the positional information detection part at an opening start position of the valve body, the opening start position to position zero.

Abstract: An operator is able to easily perform down-tuning while still achieving superior responsiveness and, in some cases, obtain an equivalent responsiveness as that obtained from the flow rate control device currently being used. In a flow rate control device that performs feedback control of a fluid control valve such that a measured flow rate closely approximates a target flow rate, there are provided a response lag input section that inputs a response lag set value, which is a value showing a response lag that an operator wishes to set, and a response lag generating section that generates response lags used in the feedback control in accordance with the response lag set values.

Abstract: In a gas flow monitoring method using a MFC (a flow control device) for controlling a flow rate of process gas from a process gas supply source and supply the process gas to a predetermined process chamber, a start shut-off valve placed upstream of the MFC, and a pressure gauge placed between the start shut-off valve and the MFC, the start shut-off valve is closed and a drop of pressure on an upstream side of the MFC is measured by the pressure gauge to measure a flow rate of the MFC, thereafter, the start shut-off valve is opened to monitor the flow rate of the MFC. The MFC is switched from an ON state to an OFF state before the start shut-off valve is opened. The method enables in-line monitoring a low rate of process gas without affecting a semiconductor manufacturing process.

Abstract: In order to suppress changes in opening level and flow rate associated with the thermal expansion of a resin member caused by a temperature change, a valve device that displaces a valve body by applying drive voltage to an actuator is adapted to include: a position sensor that detects the position of the valve body; a voltage regulator that regulates the drive voltage on the basis of a detected position by the position sensor; and a temperature sensor that detects the temperature of the valve body. In addition, the seating surface of the valve body is adapted to be formed of a resin member, and the voltage regulator is adapted to change the setting value of the drive voltage depending on detected temperature by the temperature sensor.

Abstract: In a flow path forming structure, axial runout of a shaft relative to a central axis generated when the shaft is inserted into the flow path is suppressed. This structure includes a flow path along which a fluid passes, and a shaft body that is inserted into the flow path. An upstream side of the shaft body and an inner circumferential surface of the flow path have a plurality of contact positions at different phases, and a downstream side of the shaft body and an inner circumferential surface of the flow path have a plurality of contact positions at different phases. The fluid flows through gaps between the shaft body and the inner circumferential surface. The contact positions on one of the upstream and downstream sides are at different phases from all of the contact positions on the other one of the upstream and downstream sides.

Abstract: An operator is able to easily perform down-tuning while still achieving superior responsiveness and, in some cases, obtain an equivalent responsiveness as that obtained from the flow rate control device currently being used. In a flow rate control device that performs feedback control of a fluid control valve such that a measured flow rate closely approximates a target flow rate, there are provided a response lag input section that inputs a response lag set value, which is a value showing a response lag that an operator wishes to set, and a response lag generating section that generates response lags used in the feedback control in accordance with the response lag set values.

Abstract: In order to keep a stable flow rate at a set flow rate value when a pressure fluctuation occurs in an upstream side of a valve, without providing an additional sensor for detecting a pressure fluctuation, a flow rate control apparatus is provided with: the valve; a flow rate sensor; a valve control part configured to control the valve so that a deviation between a set flow rate value and a measurement flow rate value is reduced, on the basis of the deviation and a set control coefficient; and a control coefficient setting part configured to set the control coefficient so that when a pressure rise occurs in the upstream side of the valve, a decreased amount in flow due to a decreased opening of the valve and an increased amount in flow due to an increased amount of a differential pressure before and after the valve, are balanced.

Abstract: In a gas flow monitoring method using a MFC (a flow control device) for controlling a flow rate of process gas from a process gas supply source and supply the process gas to a predetermined process chamber, a start shut-off valve placed upstream of the MFC, and a pressure gauge placed between the start shut-off valve and the MFC, the start shut-off valve is closed and a drop of pressure on an upstream side of the MFC is measured by the pressure gauge to measure a flow rate of the MFC, thereafter, the start shut-off valve is opened to monitor the flow rate of the MFC. The MFC is switched from an ON state to an OFF state before the start shut-off valve is opened. The method enables in-line monitoring a low rate of process gas without affecting a semiconductor manufacturing process.

Abstract: The present invention provides a fluid control valve that improves usability by eliminating misunderstanding of a user. The fluid control valve includes a valve seat, a valve body disposed to be approachable to and separable from the valve seat, an actuator configured to move the valve body in an approaching or separating direction, a positional information detection part configured to detect a value corresponding to a relative position of the valve body with respect to the valve seat, and a position output part configured to set, irrespective of positional information acquired by the positional information detection part at an opening start position of the valve body, the opening start position to position zero.

Abstract: An optical encoder, comprising a plurality of light receiving elements 1-12, receiving light that has passed through or been reflected by a scale having a lattice of pitch P, and outputting four-phase signals that have been respectively offset in phase by an integer number of times 90° (1/4P). 12 light receiving elements being are in the lateral direction (scale longitudinal direction) with gaps between them of P/60 or 2P/60, four arbitrary light receiving elements arranged next to each other in a row all output signals of different phases, and light receiving elements respectively outputting signals of same phase have three lateral widths of 7OP/60, 13P/60 or 20P/60.

Abstract: In order to keep a stable flow rate at a set flow rate value when a pressure fluctuation occurs in an upstream side of a valve, without providing an additional sensor for detecting a pressure fluctuation, a flow rate control apparatus is provided with: the valve; a flow rate sensor; a valve control part configured to control the valve so that a deviation between a set flow rate value and a measurement flow rate value is reduced, on the basis of the deviation and a set control coefficient; and a control coefficient setting part configured to set the control coefficient so that when a pressure rise occurs in the upstream side of the valve, a decreased amount in flow due to a decreased opening of the valve and an increased amount in flow due to an increased amount of a differential pressure before and after the valve, are balanced.

Abstract: An optical encoder, comprising a plurality of light receiving elements 1-12, receiving light that has passed through or been reflected by a scale having a lattice of pitch P, and outputting four-phase signals that have been respectively offset in phase by an integer number of times 90° (1/4P). 12 light receiving elements being are in the lateral direction (scale longitudinal direction) with gaps between them of P/60 or 2P/60, four arbitrary light receiving elements arranged next to each other in a row all output signals of different phases, and light receiving elements respectively outputting signals of same phase have three lateral widths of 70P/60, 13P/60 or 20P/60.

Abstract: An encoder has the capability of outputting a stable displacement signal with small distortion. The encoder includes a first scale and a second scale. The first or second scale has a scale pattern in which pattern elements are arranged in such a manner that the spacings between adjacent pattern elements are not constant but vary in phase relative to the reference phase of a reference pattern element by amounts of P/(2.multidot.L), P/(2.multidot.m), P/(2.multidot.n), P/(2.multidot.o), . . . (L, m, n, o, . . . are positive integers, P is the mean pattern period) and by amounts of combinations of sums of these values.

Abstract: The optical encoder is capable of detecting phases at positions which coincide more strictly than the phase detecting positions of a conventional optical encoder, and is thereby capable of outputting less distorted displacement signals with a sufficient averaging effect and detecting the phases more accurately. An amount of a light having passed through a first grating is received directly with a light receiving section and output as an electric signal. On the basis of the fact that the electric signal is varied dependently on a relative displacement between the first grating and the light receiving section, the relative displacement is detected. The light receiving section includes a plurality of grating-like photo detecting devices which have fine widths and are arranged in a grating-like shape in a mixed manner within a minute section so as to correspond to four phases.

Abstract: The amount of the light beam passing through two diffraction gratings is output as an electrical signal by a photo detector. The amount of relative displacement of the diffraction gratings is detected according to the electric signal (output signal) that changes in proportion to the relative displacement. Groove portions and ridge portions are alternately arranged on the first diffraction grating, through which the light beam passes and undergoes wavefront modulation by mutual interference of the zeroth-order diffracted light. This eliminates interference of the zeroth-order diffracted light with a diffracted light of another order, and eliminates changes in the fundamental wave component of the output signal caused by changes in the gap between the two diffraction gratings. The output signal can be made not to include a high-order component by a predetermined modification to at least one of either the array pitch or width of a transparent portion in the second diffraction grating.

Abstract: An optical encoder comprising a first scale and photo sensitive elements that shift relative to the first scale along the length of the first scale for determining a relative position based on a plurality of signals having a predetermined phase difference from the photo sensitive elements. The optical encoder comprises groups of photo sensitive elements, wherein each group comprising a plurality of photo sensitive elements arranged side by side in the direction of the length, and wherein each photo sensitive element has a width corresponding to the width of the pattern of the first scale. The groups of photo sensitive elements corresponds respectively to the plurality of signals. The photo sensitive elements belonging to one photo sensitive element group and the photo sensitive elements belonging to the other photo sensitive element group are arranged side by side in a mixed fashion in the direction of the length.

Abstract: A scale and encoder are capable of stably outputting a displacement signal with less distortion. The scale has grating pattern lines arranged successively, and the widths of the pattern lines of a second scale are not P/2 but are determined to remove high-order distortion components on the grating pattern. For example, for removing the third and fifth order distortion components, the scale is made to include two slits in which pattern line widths are 17P/30 and 23P/30.

Abstract: A position detecting apparatus utilizing optical interferometry changes the wavelength of a light beam from the light source. The variation in the wavelength causes an increment and decrement Cx, Co in the number of waves in the measurement and reference lengths Lx, Lo. The position data calculating section calculates the measurement length Lx on the basis of the detected increment and decrement Cx, Co and the reference length Lo according to an equation, Lx=Lo(Cx/Co). The position detecting apparatus can easily detect an absolute position of an object to be detected.