JPH11344305A - Position detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable highly precise detection of the position of a moving object with simple structure. SOLUTION: A reflecting member 10 having four reflecting surfaces 11-14 constituting a recessed surface C of a quadrangular pyramid form is installed on a moving member W. The recessed surface C is irradiated with a laser beam which is outputted from a light source 16 and has a specified diameter. The respective reflecting surfaces are irradiated with the laser beam, and the respective reflected lights enter light receiving elements 21-24 which are arranged facing the reflecting member 10. When the moving member W is displaced in the X axis direction or the Y axis direction, the intensities of reflected light entering the light receiving elements 21-24 change. Thereby the direction and the amount of displacement are detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device which detects how much a member moving in a plane is displaced from a predetermined reference position and can position the member at the reference position.

[0002]

2. Description of the Related Art When inspecting the surface of an object to be measured, the object to be measured is moved in two directions of an X-axis and a Y-axis parallel to the surface of the object. It is also moved in the Z-axis direction perpendicular to the surface. In this case, since it is necessary to move the object to be measured in the XYZ three-axis directions and position the object to be measured at a predetermined position, the position of the object to be measured is detected with high accuracy, and the displacement amount with respect to the reference position is determined. That is, the amount of movement must be detected. Similarly, when the object to be measured is displaced in an inclined direction or displaced in a rotating direction during the movement of the object to be measured, it is necessary to measure the amount of the displacement.

[0003]

For example, in a projection exposure apparatus, ie, a stepper for projecting and exposing a pattern drawn on a reticle onto a semiconductor wafer to form a circuit pattern, a predetermined pattern of the projection exposure apparatus is required. It is necessary to position the wafer at the position. Therefore, in the related art, the position of the mark formed on the wafer is optically read, and the position of the wafer is detected by performing image processing on the read image data. In that case, not only a complicated positioning device having an image processing function is required, but also the position detection accuracy is limited.

Further, a scanning probe microscope (scanning pr
In an obe microscope), a piezoelectric element is used for positioning. However, when the displacement is nonlinear with respect to the applied voltage and accuracy is required due to its hysteresis, it is a displacement meter having a linear characteristic. It is necessary to measure the displacement in the direction.
However, if three independent sets of displacement meters are provided, the position detection device becomes complicated.

An object of the present invention is to enable the position of an object to be measured to be detected with high accuracy with a simple structure.

[0006]

A position detecting device according to the present invention irradiates a moving body with incident light from a light source and reflects light from the moving body in a direction perpendicular to the incident light of the moving body. A position detection device for detecting a certain amount of movement in a lateral direction, wherein at least three of the moving bodies are formed at predetermined angles around the incident light with the position irradiated with the incident light as a vertex. A pyramid-shaped reflecting surface, at least three light receiving means for receiving light reflected from each of the reflecting surfaces, and the input light according to the intensity of reflected light reaching two of the light receiving means. An X-direction intensity difference calculating means for calculating an intensity difference in the X direction perpendicular to the emitted light; and an X-direction intensity difference calculating means for calculating the intensity difference in the X direction according to the intensity of the reflected light that reaches two of the light receiving means. At right angles to Y-direction intensity difference calculation means for calculating the Y-direction intensity difference; X-direction movement amount calculation means for calculating the X-direction movement amount of the moving body based on the X-direction intensity difference; Y of the moving object based on the intensity difference
And a Y-direction movement amount calculating means for calculating the movement amount in the direction.

A position detecting apparatus according to the present invention irradiates a moving body with incident light from a light source and detects the amount of movement of the moving body in a direction of inclination with respect to the incident light based on reflected light from the moving body. And at least three pyramid-shaped reflection surfaces formed on the moving body at a predetermined angle around the incident light with the optical axis center of the incident light as a vertex, and from each of the reflection surfaces At least three light receiving means for receiving the reflected light, and directions different from each other with respect to a reference position of the reflected light which has reached two of the light receiving means in the X direction with respect to the incident light. X direction shift amount calculating means for calculating the shift amount of the light, and directions different from each other with respect to the reference position of the reflected light that has reached two of the light receiving means, with respect to the X direction. A Y-direction displacement amount calculating means for calculating a shift amount in the Y direction becomes the angular direction, X for calculating the tilt movement amount in the X direction of the moving object based on the displacement amount of the X-direction
A directional inclination calculating means, and a Y-direction inclination calculating means for calculating a moving amount of the moving body in the Y-direction based on the shift amount in the Y-direction.

The position detecting device according to the present invention irradiates a moving body with incident light from a light source and reflects light from the moving body in a vertical movement amount in a direction in which the moving body approaches and separates from the light source. A position detection device for detecting at least three pyramid-shaped reflecting surfaces formed on the moving body at a predetermined angle around the incident light with the optical axis center of the incident light as a vertex, At least three light receiving means for receiving the reflected light from each of the reflecting surfaces, and a Z-direction shift amount calculating means for calculating a shift amount in the same direction with respect to a reference position of the reflected light reaching each of the light receiving means And a vertical movement amount calculating means for calculating a vertical movement amount which is a direction in which the moving body approaches and separates from the light source based on the shift amount in the Z direction.

The position detecting device of the present invention irradiates a moving body with incident light from a light source and detects the amount of movement of the moving body in the direction of rotation about the optical axis with respect to the incident light by reflected light from the moving body. A position detecting device, wherein at least three pyramid-shaped reflecting surfaces formed on the movable body at a predetermined angle around the incident light with the optical axis center of the incident light as an apex; At least three light receiving units for receiving the reflected light from the reflecting surface, a rotational direction shift amount calculating unit for calculating a shift amount in a direction around the optical axis with respect to a reference position of the reflected light reaching each of the light receiving units, A rotational movement amount calculating unit configured to calculate a rotational movement amount of the moving body around the optical axis based on an amount of displacement in a rotation direction.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[0011] Figure 1 is a diagram showing the basic principle of the position detection apparatus according to an embodiment of the present invention, X-direction, a linearly movable in three dimensional directions Y and Z directions, theta _X direction and theta _Y direction is freely tilting movement, the moving member W, which is rotatable in the R direction is provided with the reflecting member 10.

The reflecting member 10 has a quadrangular pyramid-shaped concave surface C, and the concave surfaces C are mutually formed at a predetermined angle γ.
The first reflecting surface 11 and the second reflecting surface 12 facing each other, that is, facing each other, are opposed to each other at a predetermined angle γ with respect to the reflecting surfaces 11 and 12 at an angle of 90 degrees. And a fourth reflecting surface 14. In the case shown in the figure, the concave surface C is formed by making a pyramid-shaped depression or indentation on the surface of the reflecting member 10 using a diamond-made pyramid-shaped indenter of a Vickers hardness tester. The angle, that is, the angle γ formed by the two opposing reflecting surfaces about the vertex 15 of the concave surface C is 136 degrees.

A light source 16 for irradiating the concave surface C with a laser beam is disposed so as to face the reflecting member 10. As the light source 16, a helium-neon (He-Ne) laser is used to generate a circular beam spot, and a semiconductor laser is used to generate a rectangular beam spot.

A first light receiving a light reflected by the first reflection surface 11 among the incident light 17 of the beam from the light source 16.
A second light receiving element 22 for receiving the light reflected on the second reflecting surface 12, a third light receiving element 23 for receiving the light reflected on the third reflecting surface 13, 4th
And a fourth light receiving element 24 that receives the light reflected by the reflection surface 14 of each of the above.

Therefore, as shown in FIG. 2, the positional relationship between the four light receiving elements 21 to 24 with respect to the reflection member 10 is as follows. The first light receiving element 21 and the second light receiving element 22 One transverse direction that is perpendicular to
The third light receiving element 23 and the fourth light receiving element 24 are opposed to each other in a Y direction which is a direction perpendicular to the incident light 17 and a direction perpendicular to the X direction, Each of the light receiving elements 21 to 24 is arranged so that the phase angle ε adjacent to the optical axis of the incident light 17 is 90 degrees.

Each of the light receiving elements 21 to 24 may be attached to a fixed member arranged adjacent to the moving member W, or may be attached to the moving member W via a support member (not shown).

FIG. 3 is a cross-sectional view of the reflecting member 10 taken along line 3-3 in FIG. 1. FIG. 3 (A) shows the incident light when the concave surface C is irradiated with a circular laser beam incident light 17 from a light source 16. FIG. FIG. 3 is a diagram illustrating a locus of the optical axis center of light and the optical axis center of reflected light traveling toward light receiving elements 21 and 22. The laser beam has a predetermined beam diameter. When the laser beam is incident on the reflecting member 10, a laser beam having a spot diameter d corresponding to the beam diameter is irradiated on the concave surface C as shown in FIG.

FIG. 5A is a view showing a state in which the laser beam from the light source 16 is irradiated on the concave surface C with its optical axis center coincident with the apex 15. In this case, the four reflecting surfaces 11 are shown. To 14 have the same irradiation area S1 to S4, respectively.
As a result, a laser beam is irradiated.

When the reflecting member 10 is displaced in the X-axis direction by the moving member W from this state, the first and second reflecting surfaces 1
The irradiation areas of the laser beams applied to the laser light sources 1 and 12 are different. The X direction is perpendicular to the incident light from the light source 16 and the first and second reflecting surfaces 11, 1
2 is a direction facing each other.

FIG. 5B is a diagram showing the irradiation areas S1 to S4 of the laser beam in a state where the reflecting member 10 has moved to the left in the figure as shown by the arrow from the state of FIG. 5A. When moved in this direction, the irradiation area S1 on the reflection surface 11 is smaller than the irradiation area S2 on the reflection surface 12, and the irradiation areas S3 and S4 on the other reflection surfaces 13 and 14 are the same.

Similarly, when the moving member W is displaced in a direction perpendicular to the incident light and in a direction in which the third reflecting surface 13 and the fourth reflecting surface 14 face each other, that is, in the Y direction. In this case, the irradiation area on the third and fourth reflection surfaces 13 and 14 changes, and the irradiation area on the first and second reflection surfaces 11 and 12 becomes the same. Further, when the moving member W is displaced in both the X direction and the Y direction, the four reflecting surfaces 11 to 11 are displaced.
The irradiation area for 14 will be different from each other.

Therefore, when the irradiation area changes in this manner, the light receiving elements 21 to 21 are reflected from the respective reflecting surfaces 11 to 14.
Since the intensity of the reflected light reaching 24 changes, the position where the optical axis center of the incident light coincides with the vertex 15 of the concave surface C is determined as a reference position by detecting the intensity of the reflected light.
The direction in which the moving member W is perpendicular to the incident light 17 (lateral direction)
When the moving member W is displaced, that is, moved, the moving member W is displaced in each of the X direction and the Y direction.

The amount of displacement that can be obtained is the beam diameter d
Is within the range of the concave surface C, and the beam diameter d
Is set to a value smaller than the concave surface C. By detecting the amount of displacement, for example, when positioning the moving member W at the reference position, if the moving member W is moved so that the amount of deviation from the reference position is determined to be zero,
The moving member W can be positioned at the reference position.

In FIG. 3B, as shown by a two-dot chain line, a state where the surface of the reflecting member 10 is perpendicular to the incident light 17 is set as a reference position, and from that position, as shown by a solid line, is a diagram illustrating a case where the inclined counterclockwise by an angle theta _X in FIG. The inclination direction is the first and second reflection surfaces 1
In this case, the distance between the vertex 15 and each of the light receiving elements 21 and 22 is L, and the first light receiving element 21 has The reflected light is incident on the position shifted by 2Lθ from the reference position, and the reflected light is incident on the second light receiving element 22 toward the position shifted in the opposite direction by the same distance from the reference position.

Similarly, when the third and fourth reflecting surfaces 13 and 14 are inclined in the direction facing each other, that is, in the Y direction (θ _Y direction), the third and fourth light receiving elements 23 and 24 are also provided. Is shifted from the reference position in the opposite direction to the reference position.

Therefore, when the moving member W is inclined, the amount of deviation of the position where the light reflected from the reflecting surface is incident on the light receiving element from the reference position is detected, whereby the inclination angle and the inclination direction of the moving member W are detected. And can be detected.

In FIG. 4A, as indicated by a two-dot chain line, the distance in the optical axis direction between the surface of the reflecting member 10 and the light source 16 is D.
Is set as a reference position, and from this position, as shown by a solid line, the moving member W moves in the Z direction and the light source 1
FIG. 9 is a diagram illustrating a case where the vehicle approaches by distance E toward 6.

In this case, when the reflection angle of each reflected light is α, the reflected light from the first reflecting surface 11 is the first reflected light.
The light reflected from the second reflecting surface 12 is shifted from the reference position by Ecosα in the same direction with respect to the second light receiving element 22. When the moving member W is displaced so as to approach the light source 16 in this manner, the position at which the reflected light reaches the light receiving element is shifted in a direction approaching the optical axis.

In this case, the reflected light from the third reflecting surface 13 and the reflected light from the fourth reflecting surface 14 are also separated from each other by the same distance in the same direction with respect to the respective light receiving elements 23 and 24. The incident light will be shifted.

Therefore, the first and second light receiving elements 21,
When each reflected light is incident on the light source 16 in the same direction and shifted by the same distance, the moving member W is displaced in the direction approaching the light source 16 along the optical axis or in the direction away from the light source 16. Whether the displacement has occurred can be detected and the amount of displacement can be detected.

In this manner, it is possible to detect the amount of displacement in the direction along the optical axis of the incident light, that is, in the vertical direction (Z direction) by moving toward and away from the light source 16.

FIG. 4B is a diagram showing the shift of the reflected light reaching the light receiving element 21 when the moving member W rotates around the optical axis, and shows the shift of the reflected light before the moving member W rotates. The trajectory of the center of the optical axis is indicated by a two-dot chain line, and the trajectory of the center of the reflected light after rotation is indicated by a solid line. When the moving member W rotates, the reflected light shifts in the direction around the optical axis with respect to the reference position, and the amount of rotation and the rotation angle of the moving member W can be obtained by obtaining the amount of the shift. When the moving member W rotates, the reflected light reaches the respective light receiving elements with the same shift amount around the optical axis similarly.

FIG. 6A is a diagram showing a specific example of the light receiving element 21, and the same light receiving elements 22 to 24 are used. FIG. 6B shows two light receiving elements 21 and
FIG. 22 is a sectional view taken along the X-axis direction of FIG.

Each light receiving element is a two-dimensional PSD element, and has a P layer on the detection surface side where the reflected light is incident and an N layer on the back surface side.
And a three-layer structure of a layer and an intermediate I layer on the surface of the silicon substrate. Light incident on the light receiving element is photoelectrically converted and each of the electrodes 21 _X1 provided on the P layer as a photocurrent.
~ 21 _Y2 .

Therefore, when the spot light is incident on the light receiving surface of the light receiving element, an electric charge proportional to the light intensity of the reflected light from the reflecting surface is generated at the incident position, and the generated electric charge is converted into a photocurrent by the P which is a resistive layer. Output from the electrodes through the layers. As a result, by detecting the intensity of the photocurrent output from the electrode, as shown in FIG.
The irradiation area of the laser spot irradiated from the light source 16 to 1 to 14 can be detected. As shown in FIG. 3A, when the light intensity of the reflected light incident on the two light receiving elements 21 and 22 paired in the X-axis direction is detected, the direction becomes a direction perpendicular to the incident light 17. The displacement amount of the moving member W in the X direction can be detected. The resistance layer has a uniform resistance value as a whole, and the photocurrent is divided and output in inverse proportion to the distance to the electrode.

As shown in FIG. 6B, the reference position of the reflected light entering the light receiving element 21 is _{defined as} the center position (X ₀ ) of both electrodes 21 _X1 and 21 _X2 of the light receiving element 21 and the reflected light is reflected. Is the light source 1 by X1 as shown in FIG.
When the incident light 17 from the light source 6 is shifted in the direction approaching the optical axis, the current I ₁ extracted from the electrode 21 _X1 on the side closer to the incident light 17 and the current I ₁ extracted from the electrode 21 _X2 on the far side are _{increased. 2} will vary depending on the shift amount X ₁ of the incident position of the reflected light.

Therefore, by detecting the respective current values, the amount of deviation of the reflected light reaching the light receiving element from the reference position can be obtained.

As shown in FIG. 6 (B), the position where the reflected light reaches the first light receiving element 21 is shifted in a direction approaching the optical axis of the incident light 17, and the reflected light is reflected on the second light receiving element 22. of when the arrival position is displaced in a direction away from the optical axis of the incident light 17, as shown in FIG. 3 (B), can be moved member W is determined to have displaced in the inclination direction, the X ₁ The inclination amount can be detected from the value.

On the other hand, as shown in FIG.
When the moving member W is displaced in a direction along the optical axis of the incident light 17 toward the light source 16, the respective reflected lights approach the light receiving elements 21 and 22 to the optical axis of the incident light 17. The moving member W can detect the approaching movement of the moving member W, and the amount of displacement in the approaching direction can be detected from the amount of the shifting. In this manner, when the moving member W is displaced in the Z direction, that is, in the vertical direction, the displacement amount can be obtained. When the moving member is displaced away from the light source 16, the reflected light is transmitted to the light receiving elements 21 and 22.
, The moving member W can be detected to move away from the moving member W.

As shown in FIG. 4B, even when the arrival position of the reflected light is shifted from the reference position in the direction of rotation about the optical axis, the shift amount Y ₁ shown in FIG. 6A is detected. By doing so, the moving amount of the moving member W in the rotation direction can be obtained.

FIGS. 7 and 8 show the respective light receiving elements 21.
FIG. 14 is a block diagram showing a control circuit for processing signals of No. to No. 24 to calculate the amount of displacement of the moving member. As shown in FIG. 7, four electrodes 21 _{X1 to} 21 _Y2 of the first light receiving element 21 are connected to current-voltage conversion circuits 31 _{X1 to} 31 _Y2 for converting an output current from the electrodes 21 _{X1 to} 21 _Y2 , Current-voltage conversion circuits 32 _{X1 to} 32 _Y2 are connected to the four electrodes 22 _{X1 to} 22 _Y2 of the second light receiving element 22, respectively. Similarly, the third and fourth light receiving elements 23 and 24 shown in FIG. Current-voltage conversion circuits 33 _{X1 to} 33 _Y2 , 34 _X1
~ 34 _Y2 is connected.

To calculate the amount of movement of the moving member W in the X direction according to the intensity of the reflected light reaching the two light receiving elements 21 and 22, as shown in FIG. In the four current-voltage conversion circuits 31 _{X1 to} 31 _Y2 ,
An adder circuit 35a is connected to the adder circuit 35a.
As a result, the total amount of light reflected on the light receiving element 21, that is, a voltage value corresponding to the intensity of the reflected light is calculated. Similarly, the second
In order to calculate the total amount of light reflected by the light-receiving element 22, the current-voltage conversion circuits 32 _{X1 to} 32 _X2 are connected to adders 35b, respectively.

The output terminals of the respective adders 35a and 35b are connected to a subtractor 36a which outputs a voltage corresponding to the difference between the output voltage values from the respective adders 35a and 35b. The intensity difference in the X direction of the reflected light reaching the two light receiving elements 21 and 22 is calculated by 36a. As described above, the subtraction circuit 36a constitutes the X-direction intensity difference calculating means.

The output terminals of the respective adders 35a and 35b are also connected to an adder 37a, and the total received light amount of the reflected light in the X direction out of the reflected light is calculated by the adder 37.
It is calculated by a. The output voltage of the addition circuit 37a and the output voltage of the subtraction circuit 36a are sent to a division circuit 38a in order to remove an element of light quantity fluctuation, and the output value from the division circuit 38a is in the X direction. Output signal corresponding to the intensity difference of The amount of movement of the output signal in the X direction is calculated by the conversion circuit 39a in accordance with the difference in intensity.

In order to calculate the amount of movement of the moving member W in the Y direction according to the intensity of the reflected light that reaches the two light receiving elements 23 and 24, the moving member W is connected to the third and fourth light receiving elements 23 and 24. Each of the current-voltage conversion circuits 33 _{X1 to} 34 _Y2 includes an addition circuit 35 c, like the first and second light receiving elements 21 and 22.
35d, and each output terminal is connected to a subtraction circuit 36d.
b and an addition circuit 37b, and their output voltages are connected to a division circuit 38b. The output value of the dividing circuit 38b becomes an output signal corresponding to the intensity difference in the Y direction, and the conversion circuit 39b calculates the amount of movement in the Y direction corresponding to the intensity difference from the output signal.

The above-described addition circuit, subtraction circuit, and division circuit are selected by setting the characteristics of an operational amplifier, that is, an operational amplifier.

In order to calculate the amount of deviation of the reflected light that has reached the two light receiving elements 21 and 22 from the reference position and calculate the amount of tilt movement of the moving member W in the X direction, the current-voltage conversion circuit 3
Output terminals of 1 _X1 and 31 _X2 are connected to a subtraction circuit 41 a and an addition circuit 41 b, respectively, and the subtraction circuit 41 a outputs X to the reference position of the reflected light reaching the light receiving element 21.
The direction shift amount is obtained. The output voltages of the subtraction circuit 41a and the addition circuit 41b are output from the division circuit 45a after the factor of the light quantity fluctuation is removed in the division circuit 45a, corresponding to the shift amount in the X direction.

Similarly, the second light receiving element 22 also includes a subtraction circuit 42a corresponding to the subtraction circuit 41a and an addition circuit 41b.
Is connected to a dividing circuit 45b corresponding to the dividing circuit 45a.
The difference between the output values of 5a and 45b is obtained by the subtraction circuit 46a. By converting this output signal by the conversion circuit 47a, the amount of movement of the moving body W in the X direction in the tilt direction is calculated.

In order to calculate the amount of deviation of the reflected light that has reached the two light receiving elements 23 and 24 from the reference position and calculate the amount of tilt movement of the moving member W in the Y direction, the current-voltage conversion circuit 3 is used.
Output terminals of 3 _X1 and 33 _X2 are connected to a subtraction circuit 43 a and an addition circuit 43 b, respectively, and the subtraction circuit 43 a outputs Y to the reference position of the reflected light reaching the light receiving element 23.
The direction shift amount is obtained. The output voltage of the subtraction circuit 43a and the addition circuit 43b is output from the division circuit 45c after the factor of the light amount fluctuation is removed in the division circuit 45c, corresponding to the shift amount in the Y direction.

Similarly, the fourth light receiving element 24 also includes a subtraction circuit 44a corresponding to the subtraction circuit 43a and an addition circuit 43b.
Is connected to a dividing circuit 45d corresponding to the dividing circuit 45c.
The difference between the output values of 5c and 45d is obtained by the subtraction circuit 46b, and the output signal is converted by the conversion circuit 47b to calculate the amount of movement of the moving body W in the tilt direction in the Y direction.

To calculate the amount of displacement of the reflected light reaching the respective light receiving elements in the same direction with respect to the reference position, and to calculate the amount of movement of the moving member W in the vertical direction, these dividing circuits 45a, 45a are used. The output signals from 45b, 45c, 45d are
Each is sent to the addition circuit 51. This added value corresponds to the amount of deviation from the reference position, and the output signal is converted by the conversion circuit 52 to calculate the amount of movement in the Z direction.

To calculate the amount of deviation of the reflected light that has reached each light receiving element from the reference position in the direction around the optical axis and calculate the amount of rotation of the moving member W about the optical axis,
Current-voltage conversion circuit 31 connected to each light receiving element
_Y1 , _31Y2 , _32Y1 , _32Y2 , _33Y1 , _33Y2 , 3
4 _Y1 and 34 _Y2 are a subtraction circuit 41c... And an addition circuit 41d.
, And the output terminals of the respective subtraction circuits and addition circuits are divided circuits 53a, 53b, 53c, 53
d. Output signals from these division circuits are sent to an addition circuit 54. This added value corresponds to the amount of deviation from the reference position, and the output signal is converted by the conversion circuit 55 to calculate the amount of movement in the rotational direction.

Each conversion circuit 39a, 39b, 47
a, 47b, 52, 55, X
If an operation signal is sent to the shaft drive motor 4, the Y-axis drive motor, the X-direction tilt drive motor, the Y-direction tilt drive motor, the Z-axis drive motor, and the turning motor, the respective movement amounts become zero. The member W can be positioned and moved. In the illustrated embodiment, a laser beam having a beam diameter of about 112 to
, It was possible to detect the displacement with a precision of nm in the range of the displacement amount of ± 20 μm.

In the above-described position detecting device, displacement amounts or movement amounts of six axes including the movement amount in the X direction are obtained. Alternatively, the displacement amount of an arbitrary number of axes, such as only the displacement amount or any two or three axes, may be obtained.

In the control circuits shown in FIGS. 7 and 8, the movement amount is calculated by processing the analog signal from each light receiving element. The movement amount may be calculated by binarizing and processing the binarized data.

Each of the light receiving elements 21 to 24 is a surface sensor for detecting a displacement position of the reflected light in the two axial directions, and outputs an output signal for detecting a displacement in the Y direction from the electrodes 21 _Y1 and 21 _Y2. When not used, a line sensor may be used instead of the surface sensor.

In the above-described case, the four pyramid surfaces 11 to 14 of the quadrangular pyramid are formed by the concave surface C of the reflecting member 10, but as shown in FIG. By providing the projection on the reflection member 10, four pyramid-shaped reflection surfaces 11 to 14 may be formed on the projection.

FIG. 9B is a view showing a case in which a triangular pyramid-shaped projection having three reflecting surfaces 11a to 13a is provided on the reflecting member 10, and in this case, the angle ε shown in FIG. Is set to 120 degrees, the three light receiving elements corresponding to the three reflecting surfaces are used to detect the amount of light reflected from the three reflecting surfaces and the shift position, thereby detecting the above-described six-axis movement amount. You can also. Even when the reflecting surfaces have three pyramid shapes, each reflecting surface may be formed as a concave surface. The number of pyramid surfaces can be any number as long as the pyramid-shaped reflecting surface formed on the concave surface or the projection has at least three pyramid surfaces.

In the above-described embodiment, the reflected light is directly radiated to the light receiving elements 21 to 24. However, as shown in FIG. 10, the reflected light is applied by using a light guide member 61 such as an optical fiber. May be guided to the light receiving element. In that case, the light receiving element 21 shown in FIG.
Light guide members 6 at positions corresponding to the light receiving surfaces
By facing the light receiving surfaces 61a to 61d at the front end of the device 1, bundling the rear end, and allowing the light receiving element 62 to face the rear end surface,
Each of the movement amounts described above can be detected by one light receiving element 62. As the light receiving element 62 used therefor, a photodetector, that is, a photodiode divided into four parts corresponding to the number of light receiving surfaces can be used.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist thereof. For example, in the illustration, a helium-neon laser is used, but other gas lasers,
A solid-state laser and a semiconductor laser may be used.

[0061]

According to the present invention, by detecting the amount of reflected light from the pyramidal surface provided on the moving body, the amount of movement of the moving body in the direction perpendicular to the incident light can be detected. Further, by detecting the amount of deviation of the position at which the reflected light reaches the light receiving surface with respect to the reference position, it is possible to detect the amount of tilt movement, the amount of vertical movement, and the amount of rotational movement of the moving body with respect to the incident light. With a simple structure using only a light receiving element, when the moving body is slightly displaced or moved, the direction and amount thereof can be detected with high accuracy. The detection device is hardly affected by thermal expansion, and a highly reliable position detection device can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a basic principle of a position detecting device according to an embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1 showing an arrangement state of light receiving elements.

FIG. 3A is a cross-sectional view illustrating a state of reflection of incident light when the moving member is displaced in a direction perpendicular to the optical axis of the incident light, that is, in a lateral direction, and FIG. FIG. 6 is a cross-sectional view showing a state of reflection of incident light in a case where the reflection is performed.

FIG. 4A is a cross-sectional view illustrating a state of reflection of incident light when the moving member is displaced in a direction along the optical axis of the incident light, that is, in a vertical direction, and FIG. It is sectional drawing which shows the reflection situation of the incident light at the time of rotating displacement about an axis.

FIG. 5A is a plan view showing an irradiation area on each reflecting surface when a laser beam is irradiated on a reflecting member with an optical axis coincident with a vertex of a concave surface, and FIG. 5B is a plan view showing a moving member; It is a top view which shows the irradiation area of the state changed by moving to the horizontal direction.

FIG. 6A is a perspective view illustrating a specific structure of a light receiving element, and FIG. 6B is a cross-sectional view illustrating first and second light receiving elements.

FIG. 7 is a block diagram showing a part of a control unit of the position detecting device.

FIG. 8 is a block diagram showing a part of a control unit of the position detecting device.

FIG. 9A is a perspective view showing another specific example of the reflection surface, and FIG. 9B is a perspective view showing still another specific example of the reflection surface.

FIG. 10 is a schematic diagram showing another specific example of the light receiving unit.

[Explanation of symbols]

Reference Signs List 10 reflecting member 11 first reflecting surface 12 second reflecting surface 13 third reflecting surface 14 fourth reflecting surface 15 vertex 16 light source 17 incident light from light source 21 first light receiving element 22 second light receiving element 23 Third light receiving element 24 Fourth light receiving element 21 _{X1 to} 24 _Y2 electrode 31 _{X1 to} 34 _Y2 current-voltage converter 35a to 35d Addition circuit 36a, 36b Subtraction circuit 37a, 37b Addition circuit 38a, 38b Division circuit 39a, 39b conversion circuits 41a-44a subtraction circuits 41b-44b addition circuits 41c-44c subtraction circuits 41d-44d addition circuits 45a-45d division circuits 46a, 46b subtraction circuits 47a, 47b conversion circuits 51 addition circuits 52 conversion circuits 53a, 53b Division circuit 54 Addition circuit 55 Conversion circuit C Concave surface W Moving member

Claims (4)

[Claims] 1. A position detecting apparatus for irradiating a moving body with incident light from a light source and detecting a moving amount of the moving body in a horizontal direction perpendicular to the incident light by the reflected light from the moving body. And at least three pyramid-shaped reflecting surfaces formed on the moving body at a predetermined angle around the incident light with a position irradiated with the incident light as a vertex, and each of the reflecting surfaces At least three light receiving means for receiving the reflected light from the light source, and the intensity in the X direction perpendicular to the incident light according to the intensity of the reflected light that has reached two of the light receiving means. An X-direction intensity difference calculating means for calculating a difference, and an intensity difference in a Y direction perpendicular to the X direction according to the intensity of the reflected light reaching two of the light receiving means. Computed Y direction strong Difference calculation means; X-direction movement amount calculation means for calculating the movement amount of the moving body in the X direction based on the intensity difference in the X direction; and Y-direction movement of the moving body based on the strength difference in the Y direction. A position detection device comprising: a Y-direction movement amount calculating means for calculating a movement amount. 2. A position detecting device for irradiating a moving body with incident light from a light source and detecting a moving amount of the moving body in a tilt direction with respect to the incident light by reflected light from the moving body, At least three pyramid-shaped reflecting surfaces formed on the moving body at a predetermined angle around the incident light with the optical axis center of the emitted light as a vertex, and receiving the reflected light from each of the reflecting surfaces. At least three light receiving means, and a shift amount in the X direction with respect to the incident light in directions different from each other with respect to a reference position of the reflected light reaching the two light receiving means among the respective light receiving means is calculated. X direction shift amount calculating means, and Y which is different from each other with respect to the reference position of the reflected light that has reached two of the light receiving means and is perpendicular to the X direction. One A displacement amount calculating means for calculating a displacement amount in the Y direction; an inclination calculating means for calculating an inclination direction in the X direction based on the displacement amount in the X direction; and a displacement amount in the Y direction. And a Y-direction inclination calculating means for calculating the amount of tilt movement of the moving body in the Y direction based on the position. 3. A position detecting device that irradiates a moving body with incident light from a light source and detects a vertical movement amount of the moving body in a direction of approaching and moving away from the light source by reflected light from the moving body. And at least three pyramid-shaped reflecting surfaces formed on the moving body at a predetermined angle around the incident light with the optical axis center of the incident light as a vertex, and from each of the reflecting surfaces At least three light receiving means for receiving the reflected light, a Z-direction shift amount calculating means for calculating a shift amount in the same direction with respect to a reference position of the reflected light reaching each of the light receiving means, And a vertical movement amount calculating means for calculating a vertical movement amount, which is a direction in which the moving body approaches and separates from the light source, based on the shift amount. 4. A position detecting device that irradiates a moving body with incident light from a light source and detects a moving amount of the moving body in a rotation direction around an optical axis with respect to the incident light by the reflected light from the moving body. At least three pyramid-shaped reflecting surfaces formed on the moving body at a predetermined angle around the incident light with the optical axis center of the incident light as a vertex; and reflections from the respective reflecting surfaces. At least three light receiving means for receiving light; a rotational direction shift amount calculating means for calculating a shift amount in a direction around the optical axis with respect to a reference position of the reflected light reaching each of the light receiving means; A rotational movement amount calculating means for calculating a rotational movement amount of the moving body around the optical axis based on the rotation amount.