JP3959071B2 - Positioning device - Google Patents

Description

The present invention relates to a positioning method capable of accurately moving and stopping a moving body such as a stage to a target position, and a positioning apparatus using the positioning method, and in particular, to detect interference fringes on a polished surface of a magnetic head. The present invention relates to a positioning device that can accurately position the microscope stage with respect to the inspection position in a short time when moving the microscope stage toward the inspection position of the magnetic head.

  The recording medium facing surface of the magnetic head is formed in a curved curved crown shape. In order to inspect whether the crown shape is formed as designed, the recording medium of the magnetic head observed from different angles A so-called phase shift method that observes the crown-shaped interference fringes on the opposing surface, obtains the relative phase distribution of the entire surface from the light intensity distribution generated by the interference fringes, and converts it to a three-dimensional height. The method called is used. At this time, the light intensity at an arbitrary measurement point is measured for each recording medium facing surface at each angle, and the phase is obtained by performing calculation based on the height position.

  When the crown shape is inspected by this phase shift method, since the height position of the measurement point becomes data for obtaining the phase, the height position of the measurement point is accurately grasped and the position is accurately determined. It is necessary to stop the microscope.

  Here, when inspecting the crown shape of the magnetic head, the microscope is fixed to the microscope stage, and the microscope is moved and positioned at an arbitrary position by moving the stage. For this reason, conventionally, a positioning device is used which is composed of a motor for the stage and a driving means having a screw for transmitting the driving force of the motor to the stage.

  In such a positioning apparatus, when performing the positioning, the amount of movement of the stage is actually smaller than the amount of movement to the designated position compared to the amount of movement of the stage to the position designated by the user. A so-called lost motion phenomenon occurs.

Patent Document 1 shown below discloses a microscope stage in which the rotational driving force of a pulse motor is moved through a plurality of gears, a rack, and a pinion. In this microscope stage, the pulse motor is micro-step controlled so that the stage can be moved with a minute amount of driving by one pulse. When positioned at a predetermined position by moving the stage, in order to perform accurate positioning of the stage, the gear and rack, by energizing a fixed direction by a tension spring is an elastic member, gears and racks The technical idea of reducing the backlash generated at the time of meshing is disclosed.

Further, in Patent Document 2 shown below, a moving body (conveyed object) is driven by driving a pulse motor and shifting a backlash of a drive transmission gear train from a conveyance roller to a discharge roller in one direction of the gear. The technical idea of appropriately moving is disclosed.
JP 2003-107363 A JP 2002-068519 A

However, the technical idea disclosed in the above Patent Documents 1 and 2, the moving amount of the stage and the moving body is dependent on the drive amount of one step of the pulse motor, positioning accuracy of the stage or the moving object limit was Tsu Oh to.

The present invention solves the above-described conventional problems, and an object thereof is to provide a positioning device that can accurately position a moving body such as a stage.

The present invention relates to a moving body having a moving load, a pulse motor, a transmission member that moves the moving body by transmitting the rotational force of the pulse motor to the moving body, and a position detection that detects the position of the moving body. In a positioning device having means and a controller for controlling the pulse motor,
When the moving body is moving toward the target position, the controller performs the following control operation.
(1) Based on the detection output from the position detection means , measure the difference between the position of the moving body and the target position,
(2) The moving amount of the moving body obtained from the difference between the position of the moving body and the target position is a calculated moving amount of the moving body per one pulse of the pulse for controlling the driving of the pulse motor. when it becomes less than the reference amount of movement, start after stopping the pulse motor, by elastic deformation of the transmission member, the is moved toward the target position direction movement amount of less than the reference amount of movement the movable body ,
(3) Stop the moving body when the distance between the position of the moving body and the target position is within a predetermined allowable range .

For example, the present invention, the movable body, after passing through the target position is moved in the first direction toward the target position, and the first direction the movable body toward the target position It reverses to the 2nd direction which is an opposite direction, and at the time of this reverse, the said moving body is moved toward the said target position direction with the movement amount less than reference | standard movement amount by the elastic deformation of the said transmission member.

Alternatively, the present invention, the movable body, wherein toward the target position in the first direction by moving in the reference amount of movement is stopped in front of the target position, start from the stop position, the Due to the elastic deformation of the transmission member, the moving body is moved toward the target position with a movement amount less than a reference movement amount.

In the present invention, the moving body is moved at a high speed until the difference between the position of the moving body and the target position reaches a predetermined distance, and after the difference becomes less than the predetermined distance, the movement is performed. It is preferable to move the body at a low speed.

For example, the pulse motor is microstep driven with a pulse obtained by dividing one step angle into a plurality of pulses, and the moving speed of the moving body is changed from high speed to low speed by changing the number of pulses divided at one step angle. Can be switched.

Further, according to the present invention, the command signal given to the pulse motor to move the moving body is such that the command moving amount of the moving body per pulse is set to be less than the reference moving amount, and the allowable range Is less than the command movement amount.

The present invention is suitable for a configuration in which a microscope is fixed to the moving body.
In the positioning device of the present invention , when the moving body is moved, the moving body is moved by a moving amount less than a theoretical value such as a driving means. Therefore, the movable body can be positioned with high accuracy.

In the positioning device of the present invention, particularly by using lost motion, the moving amount is much smaller than the reference moving amount defined as the theoretical minimum moving amount when the moving body is moved by the driving means or the like. Thus, it is possible to appropriately move the moving body. Thereby, the moving body can be positioned with higher accuracy than the accuracy determined by the reference movement amount .

In the positioning device of the present invention , when the moving body is moved, the moving body is moved by a moving amount less than a theoretical value such as a driving means. Therefore, the movable body can be positioned with high accuracy. In particular, by using a lost motion, the moving body is moved by a much smaller moving amount than a reference moving amount defined as a theoretical minimum moving amount when the moving body is moved by a driving means or the like. Can be done appropriately. Thereby, the moving body can be positioned with higher accuracy than the accuracy determined by the reference movement amount .

FIG. 1 is an explanatory view showing a configuration of a positioning device according to an embodiment of the present invention, and FIG. 2 is a perspective view of a magnetic head for performing inspection using the positioning device shown in FIG.

  The magnetic head H1 shown in FIG. 2 is a sliding magnetic head that constitutes, for example, a magnetic recording / reproducing apparatus for video equipment that records and reproduces a recording signal on a recording medium, or a data magnetic recording / reproducing apparatus for a computer. In the magnetic head H 1, an MR thin film magnetic head 102 for reproduction, an inductive head 103 for recording, and an insulating layer 104 as a protective film are formed on a first core 101. Two cores 105 are bonded. Reference numeral 106 denotes an electrode.

The magnetic head H1 is a thin film magnetic head 102 on a surface on which a first core 101 made of alumina titanium carbide is formed via an underlayer (not shown) made of an insulating material such as Al ₂ O ₃ or SiO _2. And an insulating layer 104 made of Al ₂ O _{3 as} a protective film is formed by a thin film forming process .

  As shown in FIG. 2, the recording medium facing surface H1A of the first core 101 and the second core 102 is curved and formed in an R shape (crown shape) in the Z direction shown in the figure, which is the traveling direction of the recording medium.

The positioning device 1 shown in FIG. 1 is used to inspect whether the crown shape of the recording medium facing surface H1A of the magnetic head H1 shown in FIG. 2 is formed within an allowable range of the designed shape. The

As shown in FIG. 3, the recording medium facing surface H <b> 1 </ b> A of the magnetic head H <b> 1 is observed with a microscope 50. At this time, the microscope 50 is observed around an arbitrary observation point while moving in the vertical direction (Y1 and Y2 directions in the drawing). When the recording medium facing surface H1A is observed with the microscope 50, the interference fringes 60 based on the crown shape can be observed as shown in FIGS. Here, points a, b, c, and d shown in FIGS. 4 to 7 are observation points of the microscope 50.

  Since the interference fringe 60 repeats light and dark in 1/2 cycle, the microscope 50 is moved at a distance of 1/4 of the cycle of the interference fringe 60 to obtain a plurality of images. Observe.

In this way, the crown-shaped interference fringe 60 is observed, and the so-called phase is obtained by obtaining the relative phase distribution of the entire surface from the light intensity distribution generated by the interference fringe 60 and converting it to a three-dimensional height. A method called a shift method is performed. At this time, the light intensity at the observation point is measured for each image, and calculation is performed based on the light intensity to obtain the phase.

  When inspecting the crown shape by this phase shift method, the position of the observation point becomes extremely important data for obtaining the phase. Therefore, the position of the observation point is grasped with high accuracy, and the position of the observation point is determined. It is necessary to stop the microscope precisely at the position.

The positioning device shown in FIG. 1 1, the possible positioning of the microscope 50 with extremely high accuracy, as the positioning device 1 is suitable for inspecting a crown shape of the recording medium facing surface H1A of the magnetic head H1 by the phase shift method It is.

As shown in FIG. 1, the positioning device 1 includes a controller 2, a stage 3 that is a moving body , a scale 4, a pulse motor 5 that is a driving unit, and a driving force of the pulse motor 5 that is the driving unit. , and possess a screw 6 which functions as a transfer means for transferring the stage 3 is the moving body.

The controller 2 includes a CPU 7 and a driver 8.
In the positioning apparatus 1, the stage 3 is connected to the pulse motor 5 via a screw 6, and the stage 3 is driven in the Y1 direction in the figure by the driving force of the pulse motor 5 via the screw 6. It is moved in the Y2 direction. The microscope 50 is fixed on the stage 3. The microscope 50 observes the interference fringes 60 based on the crown shape of the magnetic head H1 .

The pulse motor 5 has a step angle of 0.36 °, and 1000 pulses are required for one rotation . The driver 8 controls the microstep drive so that one step is divided into 250 parts. Further, one pitch of the screw 6 is 1 mm.

Therefore, when the pulse motor 5 outputs one pulse, the moving amount of the stage 3 is configured to be 1 mm / 1000 pulses / 250 division = 4 nm. In the the positioning device 1, the amount of movement of 4nm is the reference movement amount of the stage 3. Further, when the pulse motor 5 is driven in 250 divisions , the moving speed of the stage 3 is low. Procedure 1 to procedure 7 (procedure 7 is any one of procedures 7a, 7b, 7c, and 7d) described later is “one cycle of positioning cycle”, but the maximum movement amount per cycle at the time of low speed is V1. It correlates with the maximum moving speed when the stage 3 is at a low speed. This V1 is determined by the frequency that can be electrically input to the driver rather than the limit due to the load of the stage 3 when the microstep of the pulse motor 5 is 250 divisions.

The pulse motor 5 is also configured to perform 25-step microstep control by the driver 8. When the pulse motor 5 is divided into 25, the moving speed of the stage 3 is high. The maximum movement amount per one cycle of the positioning cycle at this high speed is V2, which correlates with the maximum movement speed of the stage 3 at this high speed. This V2 is determined by the relationship between the load of the stage 3 and the torque of the pulse motor 5, and is a parameter required for control so as not to cause a step-out phenomenon peculiar to the pulse motor 5.

  Since the reference movement amount of the stage 3 when the pulse motor 5 outputs one pulse is 4 nm, when the stage 3 is moved to a target position and stopped, the positioning accuracy of the stage 3 with respect to the target position is limited to 4 nm. It is normal to become.

However, in the positioning apparatus 1 can position the stage 3 with a smaller distance than 4 nm (accuracy). The principle will be described below.

FIG. 8 shows a command position (nm) when commanding where to move the stage 3 from a reference point, and a movement position (from the reference point when the stage 3 is actually moved based on the command). graph showing nm), FIG. 9 is a graph in which the command position is showing an enlarged portion of up to 50nm of the graph shown in FIG.

8 "stage No.1" is intended to represent a stage when using those 1 mm / pitch as the screw 6, a reference movement amount of 4nm per pulse. While "Stage No.2" is a representation of stages when using those 0.5 mm / pitch as the screw 6, a reference movement amount of 2nm per pulse.

As shown in FIG. 8, compared to the graph when moving according to the command, the distance that the “stage No. 1” and “stage No. 2” actually moved is shorter than the command position. I understand. This is a phenomenon called “lost motion” and is caused by elastic deformation of a member (for example, screw 6) for driving the “stage No. 1” and “stage No. 2”. In “Stage No. 1” and “Stage No. 2” in FIG. 8, the difference from the graph of “when moving according to the command” is the amount of lost motion.

As shown in FIG. 8, the smaller the command position value, the smaller the actual movement amount, and the lost motion increases as the command position value decreases .

In the positioning device 1, the stage 3 is moved more than the amount of movement of the stage 3 in one pulse of the pulse motor 5 by moving the stage in a region where the lost motion is large, that is, a region where the value of the command position is small. The stage 3 is moved by a small amount. That is, when the commanded movement amount of the stage is commanded with a value smaller than the movement amount of one pulse of the pulse motor 5, for example, as can be seen from FIGS. 8 and 9 , the theoretical minimum movement amount of the stage. Movement at a value smaller than 4 nm is possible .
In the positioning device 1, the command movement amount is set to “ 1 nm ” as will be described later.

  Next, the positioning operation of the stage 3 of the positioning device 1 will be described using FIG. 1, FIG. 10, and FIG. Here, FIG. 10 is a schematic diagram for explaining the positioning operation when the center line OO of the stage 3 is moved on the same line as the broken line 21 of the magnetic head H1 at the target position 20. FIG. 11 is a diagram showing internal processing of the controller 2. Note that the measurement point a, b, c, or d of the magnetic head H1 exists on the broken line 21 of the magnetic head H1 shown in FIG.

First, as shown in FIG. 1, a signal S1, which is a signal for moving the stage 3 from the pulse generator 11 to the target position 20 shown in FIG. It is input (step 1). The signal S1, the stage 3, 1 at a minimum amount of movement how much per pulse stipulates whether it is sufficient to move the stage 3, the positioning apparatus 1 of the present embodiment, one pulse per 1nm unit Can be commanded. This is because the movement amount of the stage 3 in one pulse of the pulse motor 5 can be minutely performed using the lost motion.

From O-O line of the stage 3 in the position A as shown in FIG. 10, the difference is a distance L from the center line O'-O'line of the target position 20, the scale 4 is a position detecting means Measured in The scale 4 can be constituted by a known light scale configured with a glass lattice-like network, for example. Wherein is measured on a scale 4 distance L of the distance signal S2 is input into the CPU7 via a pulse counter (PC) 10 shown in FIG. 1 (Step 2). This signal S2 is a pulse signal, and the position of the scale 4 can be detected for each pulse together with the stage 3 by the pulse counter 10. In the positioning device 1 of this embodiment can detect the position of the stage 3 by 1nm position detection accuracy.

The signals S1 and S2 are input to the rotation direction determination means 12 of the CPU 7 via the pulse counters 9 and 10 (procedure 3).

The rotation direction determining means 12 based on the signals S 1 and the signal S2, the stage 3 relative to the target position 20 as shown in FIG. 10, it should be moved in the Y1 direction as the first direction, the determine (from the first direction opposite to a direction) second direction should be moved to a is Y2 direction, the direction signal S3 based on this determination is input to the PID control unit 13 of the CPU 7 (Step 4 ). In the signal S3, when the stage 3 is moved in the Y1 direction, a control amount C described later becomes a positive value. On the other hand, when the stage 3 is moved in the Y2 direction, the control amount C described later takes a negative value.

  The PID control means 13 performs PID control to bring the stage 3 closer to the target position 20 based on the signal S3 (procedure 5).

The PID control means 13, the based on the signal S3 output from the rotational direction determination unit 12, the required control amount of the stage 3 (i.e. necessary amount of movement of the stage 3) to calculate the C, which signal As S4, the CPU 7 inputs the movement control means 14 (procedure 6).

  The movement control means 14 controls the driving of the pulse motor 5 for moving the stage 3 based on the signal S4 calculated by the PID control means 13.

FIG. 11 shows a control method in the movement control means 14. "Max" in FIG. 14, when the micro-step the 25 division of the pulse motor 5 by the driver 8, the same value as the amount of movement per cycle of positioning cycle. The "A" represents the ratio between the division number of the pulse motor 5 division number and the time of the low speed of the pulse motor 5 at the time of the high speed, the the positioning device is 250/25 = 10. “Pitch” is the movement amount of the stage 3 per pulse at the time of the low speed, that is, the reference movement amount, and is 4 nm in the positioning device 1.

  As shown in FIG. 11, the control amount C calculated by the PID control means 13 is input to the movement control means 14 as a signal S4.

When the absolute value | C | of the control amount C is | C |> “Max”, the driver is configured to drive the pulse motor 5 with the number of pulses of {Max / (A × (Pitch)}}. A signal S5a is output to 8. At this time, the driver 8 outputs a signal 6a so as to drive the pulse motor 5 in 25 steps (step 7a), where C is a positive value. In this case, the pulse motor 5 is rotated clockwise (CW) to move the stage 3 in the Y1 direction shown in FIG. 10, and in the case of a negative value, the pulse motor 5 is counterclockwise. The stage 3 is moved in the Y2 direction shown in FIG .

When the absolute value | C | is | C |> V1, the signal S5b is output to the driver 8 so as to drive the pulse motor 5 with the number of pulses of {C / (A × (Pitch)). To do. At this time, the driver 8 outputs a signal 6b so as to drive the pulse motor 5 in 25 divided microsteps (procedure 7b). At this time, if C is a positive value, the pulse motor 5 is rotated clockwise (CW) to move the stage 3 in the Y1 direction shown in FIG. Then, the pulse motor 5 is rotationally driven in the counterclockwise direction (CCW) to move the stage 3 in the Y2 direction shown in FIG .

When the absolute value | C | is | C | ≧ “Pitch”, the signal S5c is output to the driver 8 so as to drive the pulse motor 5 with the number of pulses of {C / Pitch}. At this time, the driver 8 outputs a signal 6c so as to drive the pulse motor 5 in 250 divided micro steps (procedure 7c). At this time, if C is a positive value, the pulse motor 5 is rotated clockwise (CW) to move the stage 3 in the Y1 direction shown in FIG. Then, the pulse motor 5 is rotationally driven in the counterclockwise direction (CCW) to move the stage 3 in the Y2 direction shown in FIG .

When the absolute value | C | is | C | <“Pitch” and | C |> 0, the signal S5d is output to the driver 8 so as to drive the pulse motor 5 with one pulse. To do. This “Pitch”, that is, the reference movement amount becomes the “reference value”. At this time, the driver 8 outputs a signal 6c so as to drive the pulse motor 5 in 250 divided micro steps (step 7d). At this time, if C is a positive value, the pulse motor 5 is rotated clockwise (CW) to move the stage 3 in the Y1 direction shown in FIG. Then, the pulse motor 5 is rotationally driven in the counterclockwise direction (CCW) to move the stage 3 in the Y2 direction shown in FIG.

In this way, the procedure 1 to the procedure 7 (the procedure 7 is one of the procedures 7a, 7b, 7c, and 7d) is set as one cycle of the positioning cycle, and when the | C | becomes less than 1 nm, The stage 3 is stopped and the positioning of the stage 3 is completed. This 1 nm is defined based on the signal S1. Therefore, 1 nm is the “allowable range”. When the position of the stage 3 is located at a distance of 1 nm or more with respect to the target position 20 every cycle, the positioning cycle is repeated, and when | C | becomes less than 1 nm Finally, the positioning of the stage 3 is completed .

In the middle of the positioning cycle, when the stage 3 is moved from the position A shown in FIG. 10 in the direction indicated by the arrow according to steps 1 to 7, the stage 3 is completed at the end of one cycle of the positioning cycle. 3 may stop at a stop position A ′ positioned in front of the target position 20 (Y2 direction in the figure), or the stage 3 may stop at the stop position A in the Y1 direction of the target position 20 You may comprise so that it may stop at ''.

In the positioning device 1, first, in the procedure 7a or the procedure 7b , the moving amount C of the stage 3 is compared with the moving amounts (V1, V2 (Max)) that can be moved in one cycle of the positioning cycle. Thereby, the stage 3 can be moved with the maximum speed and accuracy without stepping out the pulse motor 5.

Next , in step 7c or 7d, the control amount C is compared based on “Pitch”. Thus, when the movement amount of the stage 3 that is required is less than "Pitch", where the printable minimum pulse by driving the pulse motor 5, by moving the stage 3, the stage it is possible to perform a fine adjustment of the third position.

In the positioning device 1, the control amount C is determined by the value obtained by dividing the control amount C by the pitch, that is, the reference movement amount in the procedures 7 a, 7 b, and 7 c. Therefore, in order to position the stage 3, when moving in the Y1 direction or the Y2 direction, shown in FIG. 10, as the shortage by the same amount as the lost motion, stopping the stage 3 in front of the target position 20, the following In this positioning cycle, the stage 3 can be moved in small increments to make up for this shortage, so that the stage 3 can be positioned with high accuracy.

However, if the stage 3 is moved in small increments, the number of positioning cycles until positioning increases, and the time required for positioning also increases. In order to suppress this, in the positioning device 1, in the case of the procedure 7 a or 7 b in which the control amount C of the stage 3 becomes large, the pulse motor 5 is controlled by 25 steps of microsteps. the driving amount of the one pulse of 5 larger, by increasing the moving speed of the stage 3, is configured to be able to quickly carry out the positioning of the stage 3.

  Further, when the control amount C of the stage 3 is large, the control amount C is determined by a value gradually increased by the “Pitch”, and is set as an output corresponding to the reference movement amount calculated from the “Pitch”. The stage 3 is configured not to pass the target position 20.

However, as described above, in the case of the procedure 7a or 7b in which the control amount C is larger, the microstep division of the pulse motor 5 is switched from 250 division to 25 division. This is because the microstep of the pulse motor 5 needs to be divided into 250 in order to perform the positioning by performing the minute movement of the stage 3, but the pulse motor that can output in one cycle of the positioning cycle. This is to prevent the moving speed of the stage 3 from slowing when the microstep is divided into 250 because the number of pulses of 5 is limited by the circuit specifications of the driver 8 and the like. By dividing the microstep of the pulse motor 5 into 25, the maximum torque range of the pulse motor 5 can be used, and as described above, the moving speed of the stage 3 can be increased.

On the other hand, in the case of the procedure 7c or 7d in which the control amount C of the stage 3 is small, by controlling the pulse motor 5 in 250 divided micro steps, the drive amount of one pulse of the pulse motor 5 is reduced. The stage 3 can be moved minutely, and the positioning accuracy of the stage 3 is improved.

  In the positioning device 1, when the pulse motor 5 is controlled by 250 divided micro steps as described above, the theoretical movement amount of the stage 3, that is, the reference movement amount is 4 nm. In spite of this, in the positioning device, the amount of movement of the stage 3 is set to 1 nm by the signal S1, and the measurement accuracy of the scale 4 is set to 1 nm by the signal S2, thereby The positioning accuracy is performed with an accuracy of 1 nm.

As described above, in the positioning device 1 of the present invention, the stage 3 is moved in a region where the lost motion is large. Therefore, even if the pulse motor 5 is driven by one pulse, the stage 3 is moved by less than 4 nm. Can be moved in quantity. Here, FIG. 12 shows only the “stage 1” corresponding to the stage 3 used in the positioning device 1 in FIG. As shown in the graph of the "Stage 1" in FIG. 12, 250 division micro step if 4nm commanded to a one pulse of the control time of the pulse motor 5, 1 nm amount of movement the "Stage 1" actually moves It becomes possible to be less than. Therefore, in the positioning apparatus 1, even if the movement amount command of the stage 3 is 1 pulse, that is, 4 nm, the stage 3 can be moved by less than 1 nm . Then, the stage 3 moving at less than 1 nm is measured with the scale 4 and the signal S2 is fed back to the controller 2, whereby the stage 3 can be positioned with an accuracy of 1 nm .

Thus, the positioning device 1, by using the lost motion, than the reference amount of movement, which is the original theoretical minimum movement of the stage 3, and can move the stage 3 in much less amount of movement By doing so, the stage 3 can be positioned with higher accuracy than the accuracy determined by the reference movement amount .

In the positioning device 1, the lost motion is used to move the stage 3 with a much smaller movement than the reference movement, which is the theoretical minimum movement of the stage 3. It is not necessary to use components such as the stage 3 and the screw 6 that are formed with a highly accurate dimension with a very small minimum movement amount itself, so that the cost of the component such as the stage 3 and the screw 6 to be used can be reduced. It becomes possible.

In step 7c, when | C | ≧ “Pitch” is set, and in step 7d, an example is set where | C | <“Pitch”, that is, the control amount | C | is set as the reference movement amount. The number of pulses for driving the pulse motor 5 is calculated by comparing the above, but the present invention is not limited to this, and instead of the reference movement amount, for example, the start of the stage 3 shown in FIG. characteristics by performing the comparison with any number who were based Dzu, the pulse motor 5 may be calculated the number of pulses for driving. In this way, it is possible to adjust the moving speed of the stage 3 and thus the positioning speed in accordance with the positioning conditions. In this case, the “reference value” in the procedure 7d is the arbitrary number.

  In the description of the positioning device 1, the example in which the signal S1 in the procedure 1 is input as 1 nm has been described. However, in the present invention, any other numerical value can be commanded. This is the “acceptable range” of the invention. In this case, the signal 2 in the procedure 2 is also matched with the same arbitrary numerical value as the signal S1, so that the position detection accuracy of the stage can be matched with the accuracy of the movement amount, and accurate positioning becomes possible. .

  Further, when positioning the stage 3 with 1 nm accuracy as described above by motor control, there is conventionally no limitation on the resolution of the motor itself, so that it can be continuously driven such as a voice coil motor or a servo motor. It was common to use. However, in the case of a motor capable of such continuous driving, torque is generated in one direction depending on the magnitude and polarity of the current. Therefore, when the stage 3 reaches the target position 20, the current value becomes a very small value. There is no holding torque, or it is in a state where it vibrates slightly with the value of the minimum resolution of the scale.

In contrast, in the positioning device 1, due to the use of the pulse motor 5 as a motor, even when the stage 3 in the target position 20 is reached, since it is possible to continue applying a current at nominal conditions, the pulse motor Since the holding torque of the stage 3 by 5 can be maintained, the stage 3 can be brought into a stationary state at the target position 20.

  In addition, when a continuously driveable motor such as a voice coil motor or servo motor is used, if the current is cut off and the control is stopped, the motor rotates due to the force applied to the stage 3 and the like. Thus, the stage 3 moves, but the use of the pulse motor 5 can suppress the movement of the stage 3 even after the control is stopped.

Explanatory drawing which shows the structure of the positioning device which is embodiment of this invention, FIG. 3 is a perspective view showing a magnetic head to be inspected using the positioning device shown in FIG. The side view which shows the state which observes the recording medium opposing surface of the magnetic head shown in FIG. 2 with an optical microscope. FIG. 3 is a plan view showing a state in which the recording medium facing surface of the magnetic head shown in FIG. 2 is observed with a microscope shown in FIG. FIG. 3 is a plan view showing a state in which the recording medium facing surface of the magnetic head shown in FIG. 2 is observed with a microscope shown in FIG. FIG. 3 is a plan view showing a state in which the recording medium facing surface of the magnetic head shown in FIG. 2 is observed with a microscope shown in FIG. FIG. 3 is a plan view showing a state in which the recording medium facing surface of the magnetic head shown in FIG. 2 is observed with a microscope shown in FIG. The graph which shows the starting characteristic of the stage which comprises the positioning device shown in FIG. A partially enlarged graph of the graph shown in FIG. FIG. 2 is a schematic diagram for explaining a positioning operation of the positioning device shown in FIG. Explanatory drawing which shows the control method of the positioning apparatus shown in FIG. A graph showing only a part of the graph shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positioning device 2 Controller 3 Stage 4 Scale 5 Pulse motor 6 Screw 7 CPU
8 Driver 9 Pulse counters 10 pulse counters 11 pulse generator 12 the rotational direction determining means 13 PID control means 14 movement control means 50 microscope

Claims (6)

A moving body having a moving load; a pulse motor; a transmission member for transmitting the rotational force of the pulse motor to the moving body to move the moving body; a position detecting means for detecting the position of the moving body; In a positioning device having a controller for controlling a pulse motor,
Positioning apparatus the moving body when moving toward the target position, in the controller, and performs the control operation described below.
(1) Based on the detection output from the position detection means , measure the difference between the position of the moving body and the target position,
(2) The moving amount of the moving body obtained from the difference between the position of the moving body and the target position is a calculated moving amount of the moving body per one pulse of the pulse for controlling the driving of the pulse motor. when it becomes less than the reference amount of movement, start after stopping the pulse motor, by elastic deformation of the transmission member, the is moved toward the target position direction movement amount of less than the reference amount of movement the movable body ,
(3) Stop the moving body when the distance between the position of the moving body and the target position is within a predetermined allowable range . The movable body, the move toward a target position in the first direction after passing through the target position, the second the a direction opposite to the first direction toward the moving body to a target position of to reverse direction, during this retrograde by the elastic deformation of the transmission member, the movable body positioning device moved so Ru claim 1 toward the target position direction movement amount of less than the reference amount of movement. Said movable body, said toward the target position is moved in the reference amount of movement in the first direction is stopped in front of the target position, start from the stop position, by the elastic deformation of the transmission member The positioning apparatus according to claim 1 , wherein the moving body is moved toward the target position by a movement amount less than a reference movement amount . The moving body is moved at a high speed until the difference between the position of the moving body and the target position is a predetermined distance, and the moving body is moved at a low speed after the difference is less than the predetermined distance. The positioning device according to claim 1. The pulse motor is microstep-driven with a pulse whose one step angle is divided into a plurality, and the moving speed of the moving body is switched from high speed to low speed by changing the number of pulses divided at one step angle. Item 5. The positioning device according to Item 4. The command signal given to the pulse motor to move the moving body sets the command moving amount of the moving body per pulse to be less than the reference moving amount, and the allowable range is the command moving amount. The positioning device according to any one of claims 1 to 5, wherein:

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