JPWO2015029827A1 - Capacitance sensor, detection system and robot system - Google Patents

Abstract

Provided are a capacitance sensor, a detection system, and a robot system that have a simple structure and can be miniaturized. A detection system includes a capacitance sensor, a rotation angle calculation unit, and a displacement amount calculation unit. The electrostatic capacitance sensor 2 includes a base material 20, a guard electrode 21, an adsorption electrode 22, four first electrodes 23, and two pairs of second electrodes 24 and 25. The rotation angle calculation unit 3 calculates the rotation angle θ from the initial position of the workpiece W based on the sum of the electrostatic capacitance of the overlapping portion between the first electrode 23 and the workpiece W. The positional deviation amount calculation unit 4 determines the initial position of the workpiece W based on the change in electrostatic capacitance of the overlapping portion between the second electrode pair 24 and 25 and the workpiece W and the rotation angle θ from the rotation angle calculation unit 3. The positional deviation amounts δx and δy in the x-axis direction and y-axis direction are calculated.

Description

  The present invention relates to a capacitance sensor, a detection system, and a robot system for detecting a tilt angle and a positional deviation of a workpiece from an initial position.

Conventionally, as this type of capacitance sensor, there is a position sensor described in Patent Document 1.
This sensor is a position sensor that measures the position of a moving stage that moves relative to the fixed portion in a plane. Specifically, a fixed electrode portion having first to third fixed counter electrode pairs facing each other at a predetermined interval is connected to the fixed portion. And the movable electrode part which has the 1st-3rd movable electrode each inserted partially between the 1st-3rd fixed counter electrode pair is connected to the movement stage. The first fixed counter electrode pair includes a first counter electrode extending in the first direction, and the second fixed counter electrode pair includes a second counter electrode extending in parallel with the first direction. The third fixed counter electrode pair has a third counter electrode extending in a second direction that intersects the first direction. Furthermore, the first to third counter electrodes have first to third capacitances that change in accordance with the insertion states of the first to third movable electrodes, respectively. Further, the first and third counter electrodes are arranged at positions shifted in the first and second directions with respect to the second and first counter electrodes, respectively.

  As a result, the capacitance changes in the opposite directions are caused by the rotation of the moving stage. Therefore, the rotation angle of the moving stage can be determined by using the change in the capacitance in the opposite direction. It can be detected as a difference in capacitance between the counter electrode and the second counter electrode. On the other hand, the translational movement of the moving stage in the second direction can be detected by canceling the influence of the rotational movement as the sum of the first counter electrode and the second counter electrode. The translational movement of the moving stage in the first direction can be detected by correcting the influence of the rotational movement on the change in the capacitance of the third counter electrode.

JP 2013-024701 A

  However, in the conventional sensor described above, the number of electrodes for detecting a change in capacitance is large, and the assembly structure between the electrodes is complicated. For this reason, the sensor itself is complicated and increased in size, resulting in an increase in the number of manufacturing steps and manufacturing costs.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a capacitance sensor, a detection system, and a robot system that have a simple structure and can be miniaturized.

In order to solve the above-mentioned problems, the invention of claim 1 is characterized in that a guard electrode laminated on a substrate via a first dielectric layer and grounded, and a second dielectric layer on the guard electrode via a second dielectric layer. A rotation angle from the initial position of the workpiece, comprising: a plurality of arranged first electrodes; and a suction portion for sucking a polygonal workpiece and maintaining a constant distance between the first electrode and the workpiece. Each of the plurality of first electrodes is disposed around the suction portion, and each of the first electrodes is positioned when the work sucked by the suction portion is located at the initial position. A plurality of first electrodes are arranged such that the center of the electrode is on a straight line passing through each vertex from the center of the workpiece and each vertex of the workpiece is positioned within the shape of each first electrode.
With this configuration, when the workpiece is sucked by the suction portion, the facing distance between the workpiece and the first electrode is kept constant. At this time, when the sucked work is rotating from the initial position, each vertex of the work is shifted from the initial position. For this reason, the sum of the electrostatic capacitances generated at the overlapping portions of the plurality of first electrodes and the workpiece differs depending on whether the workpiece is located at the initial position or rotated from the initial position. Therefore, the rotation angle from the initial position of the workpiece can be detected by taking into consideration the sum of the capacitances generated at the overlapping portions of the plurality of first electrodes and the workpiece in each state.

  According to a second aspect of the present invention, in the capacitance sensor according to the first aspect, the number of first electrodes is four, and each first electrode is either a circle, a regular square, or a rhombus, Is configured to have a square or rectangular shape.

According to a third aspect of the present invention, there is provided a guard electrode laminated on a base material via a first dielectric layer and grounded, and two pairs of second electrodes disposed on the guard electrode via a second dielectric layer. Capacitance for detecting the amount of positional deviation from the initial position of the workpiece, comprising a pair of two electrodes and a suction portion for sucking the workpiece and maintaining a constant distance between the second electrode and the workpiece. Two second electrode pairs are arranged on an x axis and a y axis orthogonal to each other within an initial position, and one of the two second electrode pairs is a second electrode pair. Are arranged side by side on both sides of the x-axis, and when the work adsorbed by the adsorbing portion is located at the initial position, one side of the work is arranged to overlap, and the other second electrode is arranged. Two second electrodes constituting a two-electrode pair are arranged side by side on both sides of the y-axis, and the workpiece is the first When located in the position, a configuration which is arranged at a position where another side of the workpiece overlap.
With this configuration, when the workpiece is sucked by the suction portion, the facing distance between the workpiece and the second electrode is kept constant. At this time, when the attracted work is displaced in the x-axis direction from the initial position, the electrostatic capacitance generated in the overlapping portion between one second electrode pair and the work is the case where the work is located at the initial position. Will be different. Therefore, by taking into consideration the electrostatic capacitance generated at the overlapping portion of one second electrode pair and the workpiece in each state, it is possible to detect the amount of positional deviation from the initial position of the workpiece in the x-axis direction. In addition, when the workpiece is displaced from the initial position in the y-axis direction, the capacitance generated at the overlapping portion between the other second electrode pair and the workpiece is different from that when the workpiece is positioned at the initial position. Become. Therefore, by taking into account the electrostatic capacitance generated at the overlapping portion of the other second electrode pair and the workpiece in each state, it is possible to detect the amount of positional deviation from the initial position of the workpiece in the y-axis direction.

  According to a fourth aspect of the present invention, in the capacitance sensor according to the third aspect, each second electrode is either a rectangle or a regular tetragon, and the workpiece has a configuration of either a square or a rectangle. did.

According to a fifth aspect of the present invention, in the capacitance sensor according to the first or second aspect, two pairs of second electrodes provided in the capacitance sensor according to the third or fourth aspect are applied. And
With this configuration, the rotation angle from the initial position of the workpiece, the positional deviation amount on the x-axis, and the positional deviation amount on the y-axis can be detected by one capacitance sensor.

  According to a sixth aspect of the present invention, in the capacitance sensor according to any one of the first to fifth aspects, the suction portion is connected to a power source and sucks the workpiece by electrostatic force, and the suction electrode, The first and second electrodes are covered with a third dielectric layer having a flat surface.

According to a seventh aspect of the present invention, there is provided a detection system according to any one of the first, second, and sixth aspects, and an overlapping portion between the plurality of first electrodes of the capacitive sensor and the workpiece. A rotation angle calculation unit that calculates the rotation angle from the initial position of the workpiece based on the sum of the capacitances generated in step S1, and based on the relational expression between the previously obtained capacitance sum and the rotation angle, A rotation angle calculation unit that obtains the current rotation angle from the sum of the electrostatic capacities.
With this configuration, when the work sucked by the suction portion of the capacitance sensor is rotating from the initial position, the rotation angle calculation unit is based on the relational expression between the sum of the capacitance and the rotation angle obtained in advance. Then, the current rotation angle is obtained from the sum of the current capacitances.

According to an eighth aspect of the present invention, there is provided a detection system comprising: the capacitance sensor according to any one of the third, fourth, or sixth aspect; and one second electrode pair of the capacitance sensor and an overlap of the workpiece. Based on the change in capacitance generated in the portion, the displacement amount in the x-axis direction from the initial position of the workpiece is calculated, and the change in capacitance generated in the overlapping portion between the other second electrode pair and the workpiece A displacement amount calculation unit for calculating a displacement amount in the y-axis direction from the initial position of the workpiece based on the electrostatic capacitance generated at the overlapping portion of the second electrode pair and the workpiece located at the initial position And a positional deviation amount calculation unit for obtaining a positional deviation amount of the workpiece based on a difference between the electrostatic capacitance generated at the overlapping portion between the second electrode pair and the workpiece at the current position.
With such a configuration, when the workpiece attracted by the attracting portion of the capacitance sensor is displaced in the x-axis direction from the initial position, the positional deviation amount computing portion is positioned at the initial position with one second electrode pair. The amount of positional deviation in the x-axis direction of the workpiece is obtained by the difference between the capacitance generated in the overlapping portion between and the capacitance generated in the overlapping portion between the second electrode pair and the workpiece at the current position. In addition, when the workpiece is displaced from the initial position in the y-axis direction, the positional deviation amount calculation unit causes the second capacitance and the second capacitance generated at the overlapping portion of the other second electrode pair and the workpiece positioned at the initial position to be second. The amount of positional deviation in the y-axis direction of the workpiece is obtained based on the difference between the capacitance generated at the overlapping portion between the electrode pair and the workpiece at the current position.

A ninth aspect of the invention is the detection system according to the seventh aspect, wherein the two second electrode pairs and the positional deviation amount calculation unit provided in the detection system according to the eighth aspect are applied, and the positional deviation amount calculation unit is The state in which the workpiece is reversely rotated by the rotation angle obtained by the rotation angle calculation unit is calculated, and the capacitance generated in the overlapping portion between the second electrode pair and the workpiece positioned at the initial position, and the second electrode pair And a function of obtaining the positional deviation amount of the workpiece based on the difference between the electrostatic capacitance generated at the overlapping portion with the workpiece in the reversely rotated state.
With this configuration, the rotation angle calculation unit calculates the rotation angle of the workpiece attracted to the adsorption unit of the capacitance sensor, and the positional deviation amount calculation unit calculates the positional deviation amount of the workpiece in the x-axis direction and the y-axis direction. Is calculated. At the time of detection of the positional deviation amount, the positional deviation amount calculation unit obtains a state in which the workpiece is reversely rotated by the rotation angle obtained by the rotation angle calculation unit, and is positioned at the initial position with the second electrode pair. The amount of positional displacement of the workpiece is obtained by the difference between the capacitance generated in the overlapping portion with the workpiece and the capacitance generated in the overlapping portion with the workpiece in the state of being reversely rotated with the second electrode pair.

A tenth aspect of the present invention is a robot system including the detection system according to any one of the seventh to ninth aspects, wherein the robot arm has a capacitance sensor connected to the tip, a rotation angle calculation unit, The controller includes a controller that controls the operation of the robot arm based on the rotation angle and the positional deviation amount obtained by the positional deviation amount calculation unit.
With this configuration, when the robot arm attracts the workpiece by the electrostatic capacity sensor connected to the tip, the rotation angle calculation unit of the detection system calculates the rotation angle from the initial position of the workpiece and calculates the displacement amount. The unit calculates a positional deviation amount on the x-axis and a positional deviation amount on the y-axis of the workpiece. Then, the controller controls the operation of the robot arm on the basis of the rotation angle and the positional deviation amount obtained by the rotational angle calculation unit and the positional deviation amount calculation unit, corrects the workpiece to a desired angle and position, and performs predetermined processing. Place in the place of.

  As described above in detail, according to the capacitance sensor of the present invention, the base material, the guard electrode laminated on the first dielectric layer via the first dielectric layer, and the second dielectric layer thereon. Therefore, it is possible to manufacture a capacitance sensor that has a simple structure and can be miniaturized. As a result, not only can the number of manufacturing processes and manufacturing costs of the capacitance sensor be kept low, but also the number of manufacturing processes and manufacturing costs of the detection system and robot system equipped with the same can be reduced. There is an effect.

1 is a perspective view showing a detection system according to a first embodiment of the present invention. It is a top view of a detection system. It is a disassembled perspective view of a capacitance sensor. It is arrow AA sectional drawing of FIG. It is a schematic plan view which shows the state of the overlap part of a circular 1st electrode and a workpiece | work. It is a diagram which shows the relationship between the area of the overlap part of a circular 1st electrode and a workpiece | work, and the rotation angle of a workpiece | work. It is a schematic plan view which shows the state of the overlap part of a square 1st electrode and a workpiece | work. It is a diagram which shows the relationship between the area of the overlap part of a square 1st electrode and a workpiece | work, and the rotation angle of a workpiece | work. It is a schematic plan view which shows the state of the overlapping part of a rhombus 1st electrode and a workpiece | work. It is a diagram which shows the relationship between the area of the overlap part of a rhombus 1st electrode and a workpiece | work, and the rotation angle of a workpiece | work. It is a schematic plan view for demonstrating position shift amount (delta) x to the x-axis direction of a workpiece | work. FIG. 10 is a partially enlarged plan view for explaining a calculation method of a positional deviation amount δx. It is the schematic which shows the robot system with which the detection system of 1st Example was applied. It is the schematic which shows the whole robot system. It is the schematic which shows the state which lifted the workpiece | work. It is sectional drawing which shows the state which adsorb | sucked the workpiece | work. It is the schematic which shows the state which correct | amends the shift | offset | difference of a workpiece | work. It is the schematic which shows the state which has arrange | positioned the workpiece | work in the desired position. It is a top view of the detection system which concerns on 2nd Example of this invention. It is a top view of the detection system which concerns on 3rd Example of this invention. It is the schematic which shows the modification of arrangement | positioning of a 1st electrode.

  The best mode of the present invention will be described below with reference to the drawings.

Example 1
FIG. 1 is a perspective view showing a detection system according to a first embodiment of the present invention, and FIG. 2 is a plan view of the detection system. Note that the capacitance sensor was displayed through various electrodes.
As shown in FIGS. 1 and 2, the detection system 1-1 of this embodiment includes a capacitance sensor 2, a rotation angle calculation unit 3, and a positional deviation amount calculation unit 4.

The electrostatic capacitance sensor 2 is a sensor for calculating a rotation angle and a positional deviation amount from the initial position of the workpiece.
3 is an exploded perspective view of the capacitance sensor 2, and FIG. 4 is a cross-sectional view taken along the line AA in FIG.
As shown in FIGS. 3 and 4, the capacitance sensor 2 includes a guard electrode 21 on the base material 20, an adsorption electrode 22 on the guard electrode 21, four first electrodes 23, and two second electrode pairs. 24, 25.
Specifically, the solid guard electrode 21 is formed on an ultrathin resin sheet 26 that is the first dielectric layer, and this resin sheet 26 is adhered onto the base material 20 by an adhesive 26a. ing. The adsorption electrode 22, the four first electrodes 23, and the two second electrode pairs 24 and 25 are formed on the resin sheet 27 that is the second dielectric layer. It is affixed on the resin sheet 26 with the adhesive material 27a so that it may cover. Further, the resin sheet 27 with the adhesive 28a is provided so that the resin sheet 28 having a flat surface as the third dielectric layer covers the adsorption electrode 22, the four first electrodes 23, and the two second electrode pairs 24, 25. It is pasted on top.

  The guard electrode 21 is an electrode for canceling the capacity change on the base material 20 side, and has a function of preventing interference from the base material 20 side to the first electrode 23 and the second electrode pair 24 and 25.

As shown in FIG. 2, the adsorption electrode 22 is an electrode for adsorbing a square workpiece W indicated by a two-dot chain line.
Specifically, the adsorption electrode 22 is a bipolar type adsorption electrode composed of two electrodes 22a and 22b, and the adsorption electrode 22 and the resin sheet 28 constitute an adsorption portion.
Specifically, a power source 29 is connected between the electrodes 22a and 22b. When a power supply voltage is supplied from the power source 29 to the electrodes 22a and 22b, the electrodes 22a and 22b are placed on the resin sheet 28 (see FIGS. 3 and 4). The workpiece W placed on the surface is adsorbed to the surface of the resin sheet 28 by electrostatic force. That is, the attracting electrode 22 attracts the entire workpiece W to the surface of the resin sheet 28 and keeps the facing distance between the workpiece W and the first electrode 23 and the facing distance between the workpiece W and the second electrode pair 24, 25 constant. It has the function to do.

The four first electrodes 23 are electrodes used to detect the rotation angle from the initial position of the workpiece W, and are arranged around the suction electrode 22.
Specifically, the four first electrodes 23 are respectively disposed immediately above the four corners of the guard electrode 21. Each first electrode 23 is set in a circular shape, and a terminal 23 a extends outward from each first electrode 23.
In this embodiment, the four first electrodes 23 are set and arranged so that the center of each first electrode 23 coincides with each vertex P of the workpiece W when the workpiece W is located at the initial position. .

The second electrode pair 24 is an electrode used for detecting the amount of positional deviation in the x-axis direction from the initial position of the workpiece W, and is composed of rectangular electrodes 24a and 24b arranged side by side.
Specifically, the electrodes 24a and 24b are disposed on the x-axis, and the electrodes 24a and 24b are located on both sides of the x-axis. When the workpiece W is located at the initial position, the electrodes 24a and 24b are arranged so that one side (right side) of the workpiece W overlaps with the central portion of the electrodes 24a and 24b.
On the other hand, the second electrode pair 25 is an electrode used for detecting the amount of displacement in the y-axis direction from the initial position of the workpiece W, and is composed of rectangular electrodes 25a and 25b arranged side by side.
Specifically, the electrodes 25a and 25b are disposed on the y-axis orthogonal to the x-axis within the initial position, and the electrodes 25a and 25b are located on both sides of the y-axis. And when the workpiece | work W is located in an initial position, the electrodes 25a and 25b are arrange | positioned so that one side (lower side) of the workpiece | work W may overlap in the center part of electrodes 25a and 25b.

The rotation angle calculation unit 3 is a part that calculates the rotation angle θ from the initial position of the workpiece W based on the sum of the capacitances generated at the overlapping portions of the four first electrodes 23 and the workpiece W.
Specifically, as shown in FIG. 1, the wirings 31 and 32 connected to the terminal 23a of each first electrode 23 and the terminal 21a of the guard electrode 21 are drawn into the rotation angle calculation unit 3, and between the terminals 23a and 21a. Is detected in the rotation angle calculation unit 3.
The voltage between the terminals 23 a and 21 a corresponds to the electrostatic capacitance generated at the overlapping portion between the work W and the first electrodes 23. Therefore, when the workpiece W rotates from the initial position (see FIG. 2), the overlapping portion between the workpiece W and the first electrode 23 changes, and the capacitance of the portion changes corresponding to the rotation angle of the workpiece W. .
In this embodiment, when the workpiece W is rotated by the rotation angle θ from the initial position, the sum of the capacitances generated at the overlapping portions of the four first electrodes 23 and the workpiece W (that is, between the four sets of terminals 23a and 21a). The relational expression (1) between the voltage sum V) and the rotation angle θ is obtained in advance.
θ = f (V) (1)
The rotation angle calculation unit 3 calculates the current rotation angle θ from the voltage sum V input from the terminals 23a and 21a based on the above equation (1), and calculates the calculated rotation angle θ from the output terminal 3a to a predetermined device. The output terminal 3b has a function of outputting to the positional deviation amount calculation unit 4 respectively.

FIG. 5 is a schematic plan view showing a state of the overlapping portion between the circular first electrode 23 and the workpiece W. FIG. 6 is a diagram illustrating the area of the overlapping portion between the circular first electrode 23 and the workpiece W and the workpiece W. It is a diagram which shows the relationship with a rotation angle.
The inventors adopted the circular first electrode 23 in this embodiment as described above. This is based on the simulation results shown in FIGS.
That is, as shown in FIG. 5, first, a circular first electrode 23 having a diameter of 20 mm is arranged in a square shape, and a square workpiece W having a 150 mm square is placed on the first electrode 23 as indicated by a solid line in the figure. Arranged. Then, as shown by the two-dot chain line in the figure, the workpiece W is rotated by an angle θ from the initial position, and the area S (= S1 + S2 + S3 + S4) of the overlapping portion of the rotation angle θ and the four first electrodes 23 and the workpiece W is obtained. ) Was simulated. Then, the result shown in FIG. 6 was obtained.
A curve M <b> 1 indicated by a solid line in FIG. 6 indicates a relationship between the area S and the rotation angle θ when the vertex of the work W is rotated from the initial state where it is located at the center of each first electrode 23. A curved line M2 indicated by a broken line indicates a relationship between the area S and the rotation angle θ when each vertex of the workpiece W is rotated from a position shifted by 2 mm above the center of each first electrode 23 in FIG. Indicates. Further, a curved line M3 indicated by a two-dot chain line indicates an area S when the vertex of the workpiece W is rotated from a position shifted from the center of each first electrode 23 by 2 mm on the upper side in FIG. And the rotation angle θ.
As shown in FIG. 6, the areas S of these curves M1, M2, and M3 coincide within a wide range where the rotation angle θ is ± 5 °, and if this range is exceeded, the area S of the curve M1 and the curve M2 And the area S of the curve M3 differ depending on the rotation angle θ.

FIG. 7 is a schematic plan view showing the state of the overlapping portion between the square first electrode 23 and the workpiece W. FIG. 8 is a diagram illustrating the area of the overlapping portion between the square first electrode 23 and the workpiece W and the workpiece W. FIG. 9 is a schematic plan view illustrating a state of an overlapping portion between the rhombic first electrode 23 and the work W, and FIG. 10 is a diagram illustrating the relationship with the rotation angle. It is a diagram which shows the relationship between the area of the overlapping part with the workpiece | work W, and the rotation angle of the workpiece | work W. FIG.
Furthermore, the inventors also performed a simulation similar to the above for the first electrode 23 having a square shape or a rhombus shape of 20 mm square.
Then, as shown in FIGS. 7 and 9, when the square or rhombus first electrode 23 is used, as shown in FIGS. 8 and 10, each area S indicated by the curves M1, M2, and M3 is: The rotation angle θ matches only within a narrow range of ± 2 °, and when this range is exceeded, the area S of the curve M1, the area S of the curve M2, and the area S of the curve M3 differ depending on the rotation angle θ.

As is clear from the above simulation results, when the circular first electrode 23 is adopted, as shown in FIGS. 5 and 6, each vertex of the workpiece W and the center of the first electrode 23 are at the initial position. Even if the point is slightly misaligned, an accurate relational expression can be obtained between the overlapping area S and the rotation angle θ within a wide range of the rotation angle θ of ± 5 °. That is, by using the circular first electrode 23, the rotation angle θ can be accurately calculated from the detected voltage V using the above equation (1) in a wide rotation angle range.
On the other hand, when the square or rhombus first electrode 23 is employed, each vertex of the workpiece W and the center point of the first electrode 23 are located at the initial position as shown in FIGS. If the position is slightly shifted, an accurate relationship can be obtained between the overlapping area S and the rotation angle θ only within a narrow range of the rotation angle θ of ± 2 °.
From this point of view, in this embodiment, the circular first electrode 23 is employed so that the rotational angle θ of the workpiece W in the misaligned state can be accurately obtained from the voltage V. The positional deviation amount can be obtained by a second electrode pair 24, 25 and a positional deviation amount calculation unit 4 described later.
In this embodiment, the circular first electrode 23 is used for the capacitance sensor. However, the capacitance sensor using the square or rhombus first electrode 23 is not excluded from the scope of the present invention. Of course not.

  In FIG. 1, the positional deviation amount calculation unit 4 is based on the change in capacitance that occurs in the overlapping portion of the second electrode pair 24 and the workpiece W and the rotation angle θ input from the rotation angle calculation unit 3. The amount of positional deviation δx in the x-axis direction from the initial position of the workpiece W is obtained, and based on the change in capacitance that occurs at the overlapping portion of the second electrode pair 25 and the workpiece W, the displacement from the initial position of the workpiece W is determined. This is a part for calculating the positional deviation amount δy in the y-axis direction.

In the second electrode pair 24, as shown in FIG. 2, the wirings 41 and 42 connected to the terminals 24c and 24d of the second electrodes 24a and 24b are drawn into the positional deviation amount calculation unit 4, and between the terminals 24c and 24d. Is detected in the positional deviation amount calculation unit 4. The voltage between the terminals 24c and 24d corresponds to the capacitance generated at the overlapping portion between the workpiece W and the second electrodes 24a and 24b.
That is, when the workpiece W is displaced or rotated in the x-axis direction from the initial position, the overlapping portion of the workpiece W and the second electrodes 24a and 24b changes, and the electrostatic capacitance of the portion changes to the displacement of the workpiece W. And changes according to the rotation angle. Therefore, based on the rotation angle θ obtained by the rotation angle calculation unit 3 and the capacitance of the overlapping portion between the workpiece W and the second electrodes 24a and 24b (that is, the voltage between the second electrodes 24a and 24b), The calculation unit 4 can obtain the positional deviation amount δx. Details will be described below.

FIG. 11 is a schematic plan view for explaining the positional deviation amount δx of the workpiece W in the x-axis direction, and FIG. 12 is a partially enlarged plan view for explaining a calculation method of the positional deviation amount δx.
As shown in FIG. 11, after the workpiece W has shifted from the initial position indicated by the broken line to the position indicated by the two-dot chain line by the positional deviation amount δx, the center O ′ shifted from the initial position center O by the positional deviation amount δx. Is assumed to be rotated by an angle θ to reach a position indicated by a solid line.
Here, in order to facilitate understanding, as shown in FIG. 12, only the second electrode 24a having a width L will be described.
As shown in FIG. 12A, when the workpiece W is at the initial position and the detection voltage at that time is V0, the electrostatic capacitance, that is, the area of the overlapping portion between the workpiece W and the second electrode 24a is: It can be expressed as “V0 / β”. Where β is a coefficient (V / m ² ).
Thereafter, as shown in FIG. 12B, if the workpiece W is displaced in the x-axis direction by the positional deviation amount δx, and the detected voltage at that time is V1, the overlapping portion between the workpiece W and the second electrode 24a. The area of can be expressed as “V1 / β”.
Therefore, the following equation (2) is established.
V1 / β-V0 / β = (V1-V0) / β = L · δx
Therefore, ΔV / β = L · δx (2)
However, ΔV = V1−V0
That is, when the workpiece W is displaced in the x-axis direction and is not rotating, the positional deviation amount calculation unit 4 calculates the positional deviation amount δx of the workpiece W based on the formula (2), and the positional deviation amount is calculated. The quantity δx is output from the output end 4a (see FIG. 2).
Then, as shown in FIG. 12C, if the work W is rotated by a minute rotation angle θ from the state of FIG. 12B and the detected voltage at that time is V2, the overlap of the work W The area of the part decreases by the amount rotated. Specifically, since the rotation angle θ is a minute angle, the rotation angle θ decreases by the area “L ² · θ / 2” of the triangle ABC in FIG.
Therefore, the following equation (3) is established from the above equation (2).
V2 / β + L ² · θ / 2 = V1 / β = L · δx + V0 / β
Rearranging, (V2−V0) / β + (L ² · θ) / 2 = L · δx
Therefore, ΔV / β + (L ² · θ) / 2 = L · δx (3)
However, ΔV = V2−V0
That is, when the workpiece W is displaced in the x-axis direction and is rotated, the positional deviation amount calculation unit 4 calculates the positional deviation amount δx of the workpiece W based on the equation (3) to obtain the position The deviation amount δx is output from the output end 4a.
The meaning of the formula (3) is as follows.
By rotating the workpiece W backward from the state of (c) in FIG. 12 by the rotation angle θ, the workpiece W returns to the state shown in (b) of FIG. The positional deviation amount δx can be obtained from the difference between the electrostatic capacitance (V0 / β) at the initial position and the electrostatic capacitance (V1 / β) in the reversely rotated state.

In the second electrode pair 25, as shown in FIG. 2, the wirings 43 and 44 connected to the terminals 25c and 25d of the second electrodes 25a and 25b are drawn into the rotation angle calculation unit 3, and between the terminals 25c and 25d. The voltage is detected in the positional deviation amount calculation unit 4.
Also in the second electrode pair 25, similarly to the second electrode pair 24, the rotation angle θ obtained by the rotation angle calculation unit 3 and the capacitance of the overlapping portion of the workpiece W and the second electrode 25 (ie, the second electrode) 25a and 25b), the positional deviation amount calculation unit 4 calculates the positional deviation amount δy of the workpiece W in the y-axis direction. The calculation method of the positional deviation amount δy at this time is also the same as that of the positional deviation amount δx, and therefore, duplicate description thereof is omitted.

Next, an application example of the detection system of this embodiment will be described.
FIG. 13 is a schematic diagram showing a robot system to which the detection system 1-1 of the first embodiment is applied.
As shown in FIG. 13, the robot system includes a robot arm 100 and a controller 110, and the detection system 1-1 of this embodiment is assembled to the robot system.

Specifically, the back surface of the base material 20 of the capacitance sensor 2 is connected to the tip of the robot arm 100. Wiring lines 31, 32, 41 to 44 and the like extending from the adsorption electrode 22, the first electrode 23, and the second electrode pair 24, 25 are passed through the robot arm 100 and are disposed on the controller 110 side. 29, the rotation angle calculation unit 3 and the positional deviation amount calculation unit 4, respectively.
The controller 110 is a device for controlling the operation of the robot arm 100. The controller 110 can not only control the rotation and movement of the entire robot arm 100 but also turn on / off the power supply 29 of the capacitance sensor 2, the rotation angle θ and the amount of displacement obtained by the rotation angle calculation unit 3. The electrostatic capacitance sensor 2 at the tip of the robot arm 100 can be rotated and moved based on the positional deviation amounts δx and δy obtained by the calculation unit 4.

FIG. 14 is a schematic view showing the entire robot system, FIG. 15 is a schematic view showing a state where the workpiece W is lifted, and FIG. 16 is a cross-sectional view showing a state where the workpiece W is adsorbed.
By using this robot system, for example, as shown in FIG. 14, a work W placed on a pedestal 120 such as a work cassette is placed at a desired angle on a desired position on a device 130 such as an aligner. Can be arranged.
That is, the controller 110 lowers the robot arm 100 while the power supply 29 (see FIG. 13) of the adsorption electrode 22 of the capacitance sensor 2 is turned on by the controller 110, and the surface of the resin sheet 28 of the capacitance sensor 2 (FIG. 13). Reference) is brought into contact with the workpiece W. Then, since the workpiece | work W is adsorb | sucked by the adsorption | suction electrode 22 on the resin sheet 28 surface, the workpiece | work W can be lifted with the electrostatic capacitance sensor 2 by raising the robot arm 100, as shown in FIG.
At this time, since the workpiece W is adsorbed by the adsorption electrode 22, as shown in FIG. 16, the entire workpiece W is not turned over as indicated by a broken line, but the entire surface of the resin sheet 28 is indicated by a solid line. To be adsorbed. As a result, the opposing distance between the workpiece W and the first electrode 23 and the opposing distance between the workpiece W and the second electrode pair 24 (25) are held at a constant distance d.

  Then, as shown in FIG. 5, the workpiece W attracted by the capacitance sensor 2 rotates by the rotation angle θ from the initial position, and as shown in FIG. 11, only the positional deviation amounts δx and δy. When there is a deviation in the x-axis direction and the y-axis direction, first, the rotation angle θ is calculated by the rotation angle calculation unit 3 based on the above formula (1), and the rotation angle θ is output to the output end 3a. , 3b are output to the positional deviation amount calculation unit 4 and the controller 110, respectively. Next, the positional deviation amount calculation unit 4 calculates the positional deviation amounts δx and δy based on the rotation angle θ from the rotation angle calculation unit 3 and the above equation (3), and outputs it to the controller 110 from the output end 4a. Is done.

FIG. 17 is a schematic diagram illustrating a state in which the displacement of the workpiece W is corrected, and FIG. 18 is a schematic diagram illustrating a state in which the workpiece W is arranged at a desired position.
As described above, when the rotation angle θ and the displacement amounts δx and δy of the workpiece W are output from the rotation angle calculation unit 3 and the displacement amount calculation unit 4 to the controller 110, as shown in FIG. Then, the entire robot arm 100 is rotated toward the device 130 side. Then, the controller 110 rotates and moves the entire capacitance sensor 2 through the robot arm 100 to reversely rotate the workpiece W2 by the rotation angle θ, and in the x-axis direction and the y-axis direction by the positional shift amounts δx and δy. The workpiece W is moved backward to correct the workpiece W to the initial position.
In this state, as shown in FIG. 18, the controller 110 lowers the robot arm 100 to the device 130, places the workpiece W on the device 130, and turns off the power supply 29 of the capacitance sensor 2. Then, the robot arm 100 is raised. Then, the workpiece W is released from the attracting force of the attracting electrode 22 and is disposed at a desired angle on the device 130 at a desired angle, and the transfer work of the workpiece W is completed.

  As described above in detail, according to the capacitance sensor 2 applied to the detection system 1-1 of this embodiment, as shown in FIGS. 28, and a simple structure in which the guard electrode 21, the suction electrode 22, the first electrode 23, and the second electrode pair 24, 25 are formed on the resin sheets 26, 27. The size and thickness can be reduced, and as a result, the number of manufacturing steps and manufacturing costs of the capacitance sensor 2, the detection system 1-1, and the robot system can be reduced. In particular, the use of the robot system in a semiconductor manufacturing system that requires high-precision positioning of workpieces using the pre-aligner and main aligner eliminates the need for equipment such as a pre-aligner, and the cost of the system. You can go down.

(Example 2)
Next explained is the second embodiment of the invention.
FIG. 19 is a plan view of a detection system according to the second embodiment of the present invention.
As shown in FIG. 19, the detection system 1-2 of this embodiment is a system dedicated to rotation angle detection.
Specifically, the detection system 1-2 includes a capacitance sensor 2 that does not have the second electrode pair 24 and 25 and a rotation angle calculation unit 3.
With this configuration, when the workpiece W (not shown) attracted by the capacitance sensor 2 is rotated by the rotation angle θ from the initial position, the rotation angle calculation unit 3 is based on the above equation (1). The rotation angle θ is calculated, and the rotation angle θ is output from the output end 3a.
Since other configurations, operations, and effects are the same as those in the first embodiment, description thereof is omitted.

(Example 3)
Next explained is the third embodiment of the invention.
FIG. 20 is a plan view of a detection system according to the third embodiment of the present invention.
As shown in FIG. 20, the detection system 1-3 of this embodiment is a system dedicated to position shift amount detection.
Specifically, the detection system 1-3 includes a capacitance sensor 2 that does not have the first electrode 23 and a positional deviation amount calculation unit 4.
With this configuration, when the work W (not shown) attracted by the electrostatic capacity sensor 2 is displaced by the positional deviation amounts δx and δy in the x-axis direction and the y-axis direction from the initial position, the positional deviation amount. The calculation unit 4 calculates the positional deviation amounts δx and δy based on the above formula (2), and outputs them from the output end 4a.
Since other configurations, operations, and effects are the same as those in the first embodiment, description thereof is omitted.

In addition, this invention is not limited to the said Example, A various deformation | transformation and change are possible within the range of the summary of invention.
For example, in the above embodiment, the suction electrode 22 is used as the suction portion, but it is needless to say that an adhesive pad or the like may be used instead of the suction electrode 22. By setting so that the surface of the adhesive pad is exposed from the surface of the resin sheet 28, the adhesive pad exhibits the same function as the suction electrode 22.

Moreover, in the said Example, although illustrated about the electrostatic capacitance sensor 2 using the four 1st electrodes 23, the number of the 1st electrodes 23 is not limited to four, If it is multiple, it is arbitrary. is there. Moreover, although the example which set the shape of the workpiece | work W to the square was demonstrated, the shape of the workpiece | work W should just be a polygon, and a rectangle may be sufficient as it.
Furthermore, the shapes of the second electrode pairs 24 and 25 are arbitrary, and not only a rectangular shape but also a second electrode pair such as a regular square shape can be applied.

In the above embodiment, as shown by the solid line in FIG. 21, the four first electrodes 23 are arranged so that the center of the first electrode 23 coincides with the apex P of the workpiece W at the initial position.
However, the arrangement of the first electrode 23 is not limited to this. As indicated by a one-dot chain line or two-dot chain line in FIG. 21, at the initial position, the center of the first electrode 23 is on a straight line m passing from the center O of the workpiece W to the vertex P, and the vertex P of the workpiece W is the first electrode. The first electrode 23 can also be arranged so as to be located within the circle 23.

  DESCRIPTION OF SYMBOLS 1-1-1-3 ... Detection system, 2 ... Capacitance sensor, 3 ... Rotation angle calculating part, 3a, 3b, 4a ... Output end, 4 ... Position shift amount calculating part, 20 ... Base material, 21 ... Guard Electrode, 21a, 23a, 24c, 24d, 25c, 25d ... terminal, 22 ... Adsorption electrode, 22a, 22b ... Electrode, 23 ... First electrode, 24, 25 ... Second electrode pair, 24a, 24b, 25a, 25b ... 2nd electrode, 26-28 ... resin sheet, 26a-28a ... adhesive, 29 ... power supply, 31, 32, 41-44 ... wiring, δx, δy ... misalignment, θ ... rotation angle, 100 ... robot arm, 110 ... Controller, 120 ... Pedestal, 130 ... Equipment.

Claims (10)

A guard electrode laminated on a base material via a first dielectric layer and grounded, a plurality of first electrodes arranged on the guard electrode via a second dielectric layer, and a polygonal workpiece A capacitance sensor for detecting a rotation angle from the initial position of the workpiece, comprising a suction portion for holding the opposing distance between the first electrode and the workpiece constant,
The plurality of first electrodes are arranged around the suction portion, and when the work sucked by the suction portion is located at the initial position, the center of each first electrode is different from the center of the work. The plurality of first electrodes are arranged such that each vertex of the workpiece is located within a shape of each first electrode and is on a straight line passing through the vertex.
A capacitance sensor. The capacitance sensor according to claim 1,
The number of the first electrodes is four, and each first electrode is either a circle, a regular square, or a rhombus,
The workpiece has a square or rectangular shape,
A capacitance sensor. A guard electrode laminated on a substrate via a first dielectric layer and grounded; two pairs of second electrode pairs disposed on the guard electrode via a second dielectric layer; and a workpiece. A capacitance sensor for adsorbing and detecting an amount of positional deviation from the initial position of the workpiece, comprising an adsorption portion for maintaining a constant distance between the second electrode and the workpiece;
The two pairs of second electrodes are respectively disposed on the x axis and the y axis orthogonal to each other within the initial position,
The two second electrodes constituting one of the two second electrode pairs are arranged side by side on both sides of the x-axis, and the work adsorbed by the adsorbing portion is When positioned at the initial position, place it on a position where one side of the workpiece overlaps,
Two second electrodes constituting the other second electrode pair are arranged side by side on both sides of the y-axis, and when the workpiece is located at the initial position, the other side of the workpiece overlaps. Arranged,
A capacitance sensor. The capacitance sensor according to claim 3.
Each of the second electrodes is either rectangular or square.
The workpiece has a square or rectangular shape,
A capacitance sensor. The capacitance sensor according to claim 1 or 2,
Applying two pairs of second electrodes provided in the capacitance sensor according to claim 3 or 4,
A capacitance sensor. The capacitance sensor according to any one of claims 1 to 5,
The adsorption part is formed by an adsorption electrode that is connected to a power source and adsorbs a workpiece by electrostatic force, and a third dielectric layer having a flat surface covering the adsorption electrode and the first and second electrodes.
A capacitance sensor. The capacitance sensor according to claim 1, claim 2, or claim 6,
A rotation angle calculation unit for calculating a rotation angle of the workpiece from the initial position based on a sum of capacitances generated at an overlapping portion of the plurality of first electrodes of the capacitance sensor and the workpiece; Based on a relational expression between the previously obtained capacitance sum and the rotation angle, a rotation angle calculation unit that obtains the current rotation angle from the current capacitance sum;
A detection system comprising: A capacitance sensor according to any one of claims 3, 4 and 6,
Based on the change in capacitance that occurs in the overlapping portion between one second electrode pair of the capacitance sensor and the workpiece, the displacement amount of the workpiece in the x-axis direction from the initial position is calculated. A displacement amount calculation unit for calculating a displacement amount of the workpiece in the y-axis direction from the initial position based on a change in electrostatic capacitance generated in an overlapping portion between the other second electrode pair and the workpiece. And the difference between the capacitance generated in the overlapping portion of the second electrode pair and the workpiece located at the initial position and the capacitance generated in the overlapping portion of the second electrode pair and the workpiece at the current position, A positional deviation amount calculation unit for obtaining a positional deviation amount of the workpiece;
A detection system comprising: The detection system according to claim 7,
Applying the two second electrode pairs and the positional deviation amount calculation unit provided in the detection system according to claim 8,
The positional deviation amount calculation unit calculates a state in which the workpiece is reversely rotated by the rotation angle obtained by the rotation angle calculation unit, and an overlap portion between the second electrode pair and the workpiece positioned at the initial position is calculated. A function of obtaining a positional deviation amount of the workpiece by a difference between an electrostatic capacitance generated and an electrostatic capacitance generated in an overlapping portion between the second electrode pair and the workpiece in the reversely rotated state;
A detection system characterized by that. A robot system comprising the detection system according to any one of claims 7 to 9,
A robot arm having the capacitance sensor connected to the tip;
A controller for controlling the operation of the robot arm based on the rotation angle and the positional deviation amount obtained by the rotational angle computing unit and the positional deviation amount computing unit;
A robot system comprising:

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