JP3116867B2 - Light beam position detecting device and light beam position detecting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam position detecting device and a light beam position detecting method, and more particularly to an accurate light beam center and a predetermined position without using a mechanical mechanism. The present invention relates to a light beam position detecting method and a light beam position detecting device capable of measuring a positional deviation of a hole from a central portion of a target object.

[0002]

2. Description of the Related Art Conventionally, this kind of position detection method for a circular aperture output light beam has been used for highly accurate position detection of a light beam which cannot be achieved with mechanical precision . That is, in the related art, as a method of adjusting the center of the light beam to pass through the center of a predetermined circular opening provided in a predetermined target object, a predetermined supporting member is used to adjust the desired position. In general, a method of fixing a target object having an opening and a detection unit and performing measurement is used.

However, such a method has a problem in that there is a limit in mechanical accuracy for forming the supporting member, which leads to an increase in cost. As another method, for example, JP-A-3-120625 describes an information recording / reproducing apparatus, and the publication discloses a method of collecting reference light and recording light when they are condensed on a recording medium. A method for detecting a positional deviation between a light spot and a track is described, and a four-segment photodetector is used to determine the converging position of the converging point.

However, in order to measure such a conventional focus position, the four-divided photodetector is mechanically fixed by an appropriate support member having a predetermined accuracy, but the mechanical accuracy is limited. It is known that when higher precision is required, it is inappropriate. Japanese Patent Application Laid-Open No. Hei 5-34130 discloses that when measuring the flatness of a mirror for a projector, a laser beam is reflected by a mirror surface and detected by a four-segment photodetector. A method for measuring the flatness is described, but such a technique also involves the same problem as described above.

In each of the above-mentioned known examples, the center of the predetermined light beam does not pass through the center of the predetermined opening.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks of the prior art, so that the center of a light beam passes through the center of a predetermined circular opening provided in a predetermined target object. It is possible to detect and adjust the misalignment between the center of the circular aperture and the center of the light beam with a simple configuration and with high accuracy when adjusting the distance between the two. In addition, it is an object of the present invention to provide a light beam position detecting device and a light beam position detecting method which can be reduced in size and weight without requiring a mechanical structure.

[0007]

The present invention basically employs the following technical configuration in order to achieve the above object. That is, the first of the present invention
As an aspect of the present invention, a target object having an aperture through which a light beam output from an appropriate light source passes, a position detection of an output beam for detecting a center position of the light beam with respect to the center of the aperture of the target object Means for detecting the position of an output beam, wherein the means for detecting the position of the output beam uses diffracted light of the light beam passing through the aperture provided in the target object. the center of the light beam Te, which is configured so as to determine the degree of deviation of the center of at the open hole in the object,且
The output beam position detecting means detects that the target object is
It is composed of a flat plate with a plane parallel to the plane
And a light detecting means divided into a plurality at its center position.
A plurality of defects extending radially from the center of the light detection means.
In each direction from the center of the light detection means.
A first diffracted light detector provided at a fixed first distance
A second embodiment according to the present invention is a device for detecting the position of an output beam provided with an output unit. The light beam output from an appropriate light source unit is applied to an object having a predetermined aperture. In the light beam position detecting method for measuring a deviation between the center of the light beam and the center of the opening when passing through the opening, the light source provided on one surface side of the target object A plate-like detecting means provided on the side opposite to the part, a light receiving means for detecting the central part of the light beam around a predetermined central part, and a plurality of different methods from the central part. On a line extending radially, a diffracted light detecting means for detecting diffracted light of the light beam is provided,
By detecting the peak value of the diffracted light generated when the light beam passes through the aperture of the target object, the position of the detection means is determined, and then the detection means is used to detect the position of the light beam. This is a method for detecting the position of an output beam for measuring the deviation between the center and the center of the aperture.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a light beam position detecting device and a light beam position detecting method according to the present invention, diffracted light of a light beam to be used is used without using a mechanical mechanism. Then, by accurately positioning and locating the detecting means, the alignment between the center point of the opening in the target object and the center of the detecting means is accurately determined, and the state is fixed. Then, how much the center of the measurement light and the center of the opening of the target object are displaced when passing through the opening of the target object using an arbitrary measurement light Can be measured accurately and easily.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a light beam position detecting device and a light beam position detecting method according to the present invention. That is, the position detection device of the light beam in the present invention, for example, by passing a light beam output from any light source through the aperture of the target object having an aperture having a predetermined size, appropriate measurements, or when such as performing an appropriate processing, it is necessary to pass in a state where the center of the light beam which is the center portion of the opening portion and the measuring light or treatment light matches exactly In many cases, if they do not match, some adjustment operation is performed to perform an operation such that the center of the aperture and the center of the light beam exactly match.

Therefore, in the present invention, a light beam detecting means having a plane parallel to the plane constituting the target object is provided, and the center of the detecting means and the target object are detected by using a specific reference light. The center of the opening is made to match the center of the aperture in advance, and after fixing that state, in an actual operation using an appropriate measurement light, the detection unit is used to perform the operation. It is designed to determine whether or not the center of the aperture and the center of the light beam of the measuring light or the processing light pass through in a state of being exactly coincident, or to what extent they are displaced from each other. .

FIG. 1 is a cross-sectional view schematically showing the configuration of a specific example of a light beam position detecting apparatus according to the present invention. In the drawing, an opening for passing a light beam 2 output from an appropriate light source 1 is shown. The position of an output beam composed of a target object 4 having a hole 3 and an output beam position detecting means 5 for detecting the center position of the light beam 2 with respect to the center P of the opening 3 of the target object 4 In the detection device 20, the position detecting means 5 of the output beam 2 uses the diffracted light 6 of the light beam passing through the aperture 3 provided in the target object 4 to detect the position of the light beam 2. An output beam position detecting device 20 configured to determine the degree of deviation between the center O of the target object 4 and the center P of the aperture 3 in the target object 4 is shown.

The shape of the aperture 3 of the target object 4 used in the present invention is not particularly limited, but is preferably a circular aperture. In the light beam position detecting device 20 according to the present invention, the position detecting means 5 of the output beam 2 is formed in a flat plate shape as shown in FIG. A plurality of different directions ( e.g., the X-axis direction and the Y-axis direction)
Direction, etc. ) at a position separated by a predetermined first distance d1 from the center portion R of the light detection means 7.
, 8-n,... 8-n are provided.

Further, in the light beam position detecting device 20 according to the present invention, the position detecting means 5 of the output beam 2 is used.
Are the first diffracted light detecting means 8-1, 8-2,.
.. a second distance d greater than the first distance d1 from the center R on an extension of the direction in which 8-n is provided
Second diffracted light detecting means 9 provided at a position separated by two
-1, 9-2,... 9-n are provided.

A plurality of different directions extending radially from the central portion R of the light detecting means 5 used in the light beam position detecting device 20 according to the present invention are three or four directions. Is desirable. In the case of three directions, the first and second diffracted light detecting means 8 and 9 are provided on radiation whose angles extend in directions uniformly deviated from each other by 120 degrees, and there are four directions. In such a case, the first and second diffracted light detecting means 8 and 9 are provided on the radiation whose angles extend in directions evenly shifted from each other by 90 degrees.

Also, the first and second diffracted light detecting means 8 and 9
Is disposed at a predetermined position from the center of the light detecting means 7. Preferably, the peak value of the first-order diffracted light of the light beam 2 having a predetermined wavelength to be used, for example, λ is generated. And a first distance d1 from the center R of the light detecting means 7.
It can be calculated as

Further, when the second diffracted light detecting means 9 uses another light beam having a wavelength λ ′ (λ ′> λ) different from the wavelength λ, a peak value of the primary diffracted light is generated. It is provided at a position d2 (d2> d1). The output beam position detecting means 5 used in the light beam position detecting device 20 according to the present invention includes the target object 4.
Is desirably configured to be movable and pivotable in a plane parallel to the plane and in a direction intersecting the plane of the target object 4. Individual signal information output from each of the detecting means 7 and the first and second diffracted light detecting means 8 and 9 is collected via an appropriate control circuit 11 or 12, and based on the result, the central processing means For example, the X-axis direction motor means or the Y-axis direction motor means for moving the predetermined target object in the horizontal plane from the CPU 10 is appropriately rotated or controlled, or the flat plate detection means 5 is moved with respect to the plane on which the target object 4 is formed. Move in a direction that intersects or turns
It is desirable that a driving means having a motor (for example, M _X , M _Y , M θ) to be displaced is provided.

Further, in the present invention, the first and the second
It is preferable that the diffracted light detecting means 8 and 9 are configured so that at least one of them is irradiated with a peak value in the light intensity distribution of at least the first-order diffracted light of the light beam 2. The first and second diffracted light detecting means 8 and 9 according to (1) have a function that at least one of them can detect a peak value in the light intensity distribution of at least the first-order diffracted light of the light beam 2. It is desirable to have.

Furthermore, the light beam position detecting means 5 used in the light beam position detecting device 20 according to the present invention has a substantially central portion for detecting the central portion of the light beam 2. Although the configuration of the detection means 7 is not particularly limited, for example, it is possible to use a four-division type photodetector generally used as a light beam position detection means.

On the other hand, the first type used in the present invention
As the second diffracted light detecting means 8 and 9, a photodetector having a light receiving area relatively smaller than the light receiving area of the light beam position detecting means 7, such as a photodiode, is used. It is desirable to use. In the present invention, the center O of the light beam 2 passing through the opening 3 provided in the target object 4 by using the light beam position detecting device 20 is positioned at the target object 4. Opening 3
The following describes a specific example of a method of determining whether or not the vehicle passes through the center P of the image.

That is, in the light beam position detecting device 20 according to the present invention, before performing a predetermined process or an actual measurement operation using an actual measurement light, first, the opening portion of the target object 4 is opened. A preparatory operation is performed in which the center P of the plate 3 and the center R of the plate-shaped light beam position detecting means 5 are substantially matched. That is, first, a reference light different from the actual measurement light is used as the light beam that passes through the opening 3 of the target object 4.

As shown in FIG. 3, the reference light has a peak value 40 (the peak value 30 of the 0th-order diffracted light) of the light intensity of the first-order diffracted light formed through the opening 3. If the peak value is 1, the second peak value is obtained), but a peak value is generated in any of the first diffracted light detection means 8-1 to 8-n provided in the detection means 5 described above. Having such a first wavelength λ.

At this time, the reference light source 1 is arranged at a predetermined position, and the aperture 3 of the target object 4 is opened.
It is desirable that the center of the reference beam and the center of the reference light be in agreement. According to the specific examples of FIGS. 3 and 4,
The method for detecting the position of a light beam according to the present invention will be described in detail. Using a reference light having the wavelength λ, the center of the reference light passes through the center P of the opening 3 of the target object 4. After the irradiation, the first diffracted light detecting means 8-1, 8-2, 8-
A peak value 40 of the first order diffracted light of the reference light should come to all of 3, 8-4.

If any of the first diffracted light detecting means 8-
If the peak value 40 of the first-order diffracted light of the reference light does not come to 1, 8-2, 8-3, and 8-4, the driving means 13 is used to move the flat positioning detection means 5 to the target. By moving the object 4 in an arbitrary direction on a plane parallel to the plane of the object 4, all the first diffracted light detecting means 8-1, 8-2, 8-3, 8
Adjustment is made so that the peak value 40 of the primary diffraction light of the reference light comes to -4.

Such an operation may be performed simultaneously on all axes, or may be performed individually in the Y-axis direction and the X-axis direction. For example, when the adjustment in the Y-axis direction is performed first, the plate-shaped positioning detection means 5 is appropriately moved and adjusted so that the peak value comes to the first diffraction light detection means 8-1 and 8-3. Then, the same adjustment operation is performed so that the peak value comes to the first diffracted light detecting means 8-2 and 8-4 in the X-axis direction.

With this adjustment operation, the central portion R of the plate-shaped positioning detecting means 5 is moved to the opening 3 of the target object 4.
Will be coincident with the center P. Next, as shown in FIG.
The wavelength λ of the reference light is intermittently or continuously changed to λ ′. At this time, the first diffracted light detecting means 8-1, 8-2,
As a result of changing the peak value 40 of the first order diffracted light of the reference light having the wavelength λ at 8-3 and 8-4 to the wavelength λ ′ of the reference light, the peak value 40 ′ is detected as the second diffracted light. Means 9-
It should move towards 1, 9-2, 9-3, 9-4 and be fixed there.

However, if the plate-shaped positioning detecting means 5 does not form a plane completely parallel to the plane of the object 4, the second diffracted light detecting means 9-
There is a case where the peak value of the reference light does not come to any of the diffracted light detecting means 1, 9-2, 9-3, and 9-4. In that case, the plate-shaped positioning detecting means 5 is three-dimensionally displaced with respect to the plane of the target object 4, and all the second diffracted light detecting means 9-1, 9-2, 9-3, The peak value 40 'of the reference light having the wavelength λ' is adjusted to any one of the diffracted light detection means 9-4.

The adjustment operation may be performed separately in the X-axis direction and the Y-axis direction in the same manner as described above. When the adjustment operation is completed, the plate-shaped positioning detecting means 5
Constitutes a plane completely parallel to the plane of the target object 4, and the center R of the plate-shaped positioning detection means 5 completely coincides with the center P of the aperture 3 of the target object 4. It will be fixed to the state.

Accordingly, when the preparation work for the measurement is completed, the reference light is removed, and the actual measurement light or the processing light is used by using the target object 4 and the plate-like positioning detection means 5 to thereby remove the reference light. It is possible to easily determine how much the center of the light beam applied to the opening 3 of the target object 4 is displaced or coincides with the center P of the opening 3.

As another application example according to the present invention, for example, the position of the light source of the reference light or the irradiation angle can be changed based on the detection result of the above-mentioned plate-shaped positioning detecting means 5. The position and form of the target object may also be adjusted. FIG. 5 shows another specific example of the light beam position detecting method according to the present invention.
The first and second diffracted light detecting means 8 and 9 extend radially from the center portion R of the flat positioning detection means 5.
The light beam is arranged on three rays having equal angles of 0 degrees, and the position detecting means 7 of the light beam is constituted by a four-divided photodetector as in FIG.

The adjustment operation in this embodiment is exactly the same as that in the above embodiment, and a detailed description thereof will be omitted. As is clear from the above description, as the light beam position detecting method according to the second aspect of the present invention, for example, a light beam output from an appropriate light source unit has a predetermined aperture. When passing through the aperture of the target object, in the method of detecting the position of the light beam to measure the deviation between the center of the light beam and the center of the aperture, provided on one surface side of the target object A light receiving means for detecting the center of the light beam is provided around a predetermined central part on a flat detecting means provided on the side opposite to the light source part, and a plurality of light receiving means are provided from the central part. A diffracted light detecting means for detecting the diffracted light of the light beam on a line extending radially in a different manner, wherein a peak of the diffracted light generated when the light beam passes through the aperture of the target object By detecting the value, the detection means The carried out position, a position detecting method output beam using subsequent detection means for measuring the displacement between the centers of the apertures of the light beam.

That is, in the light beam position detecting method according to the present invention, the diffracted light detecting means detects the first-order diffracted light generated when the light beam passes through the aperture of the target object. It is desirable that it be configured so that the peak value can be detected. Further, in the position detecting method of the light beam according to the present invention, the first reference light is passed through the opening of the target object to generate a first primary diffracted light,
The peak value of the intensity of the first primary diffracted light is equal to all of the first
The plate-like detection means is moved and displaced within the plane formed by the plate-like detection means so as to be detected by the diffracted light detection means, and then the second reference light is transmitted to the opening of the target object. The second flat diffracted light is generated by passing through the hole, and the plate-like shape is set so that the peak value of the intensity of the second primary diffracted light is detected by all the second diffracted light detecting means. It is configured to move and displace the detecting means within the plane or to move and displace it three-dimensionally so as to form a plane different from the plane, thereby positioning the flat detecting means. is there.

Further, in the present invention, instead of the reference light, a predetermined measuring light is passed through the opening of the target object to thereby determine the center of the zero-order diffracted light of the measuring light and the positioning. This is to detect the difference from the center of the light receiving means provided at the center of the flat detection means.

[0033]

In the light beam position detecting device and the light beam position detecting method according to the present invention, the flat plate positioning detecting means 5 arranged in a plane parallel to the circular opening is provided.
Since no mechanical interface is required between the plate-shaped positioning detection means 5 and the target object 4, the center position of the circular opening can be detected with a simple configuration and with high accuracy. Become.

Thus, the displacement of the light beam from the center of the aperture can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a specific example of a light beam position detecting device according to the present invention.

FIG. 2 is a plan view showing an example of the configuration of a flat-plate positioning detection unit according to the present invention.

FIG. 3 is a diagram illustrating an example of an operation procedure of a light beam position detection method according to the present invention.

FIG. 4 is a diagram illustrating an example of an operation procedure of the light beam position detection method according to the present invention.

FIG. 5 is a perspective view showing the configuration of another specific example of the light beam position detection method according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light source of light beam 2 light beam 3 aperture 4 target object 5 flat plate positioning detection means 6 diffracted light 7 light beam position detection means 8 first diffraction light detection means 9 second Diffracted light detection means 10 ... CPU 11, 12 ... Operation circuit 13 ... Driving means

Claims (15)

(57) [Claims] 1. A target object having an aperture through which a light beam output from an appropriate light source passes, and a position detection of an output beam for detecting a center position of the light beam with respect to a center of the aperture of the target object. Means for detecting the position of an output beam, wherein the means for detecting the position of the output beam uses diffracted light of the light beam passing through the aperture provided in the target object. Te and the center of the light beam, which is configured so as to determine the degree of deviation of the center of at the open hole in the object, and, those
The output beam position detecting means is configured by the target object.
It has a flat plate shape having a plane parallel to the plane
The light detecting means divided into a plurality at the center position and the light
A plurality of different directions extending radially from the center of the detection means
Direction from the center of the light detecting means.
First diffracted light detecting means provided at a position separated by a distance of 1
Position detection of output beam characterized by having
apparatus. 2. The output beam position detecting means further comprises:
Extension of the direction in which the first diffracted light detection means is provided
On the line, from the center, a second distance greater than the first distance
Second diffracted light detection means provided at a position separated by a distance of
The output beam according to claim 1, wherein the output beam has a step.
System position detector. 3. The light detecting means radially extends from a central portion thereof.
The different extending directions may be three or four directions.
The output beam according to claim 1 or 2,
Position detection device. 4. An output beam position detecting means, comprising:
In and parallel to the plane of the object
Can move and turn in the direction crossing the plane of the target object
Claims 1 to 3, characterized in that they are configured to be
3. The output beam position detecting device according to claim 3. 5. The apparatus according to claim 1, wherein said first and second diffracted light detecting means are provided with a small number.
At least one of the light beams
Structure so that the peak value in the light intensity distribution of the folded light is irradiated.
The method according to any one of claims 2 to 4, wherein
3. The output beam position detecting device according to claim 1. 6. The first and second diffracted light detecting means are provided with a small
At least one of them is at least
A configuration that can detect the peak value in the light intensity distribution of folded light
6. The method according to claim 2, wherein
A device for detecting the position of an output beam as described. 7. The first and second diffracted light detecting means include:
The light receiving area is smaller than the light receiving area of the light detecting means.
7. The method according to claim 2, wherein
An output beam position detector according to any of the preceding claims. 8. A light beam output from an appropriate light source unit
Passes through the opening of the target object having the predetermined opening.
The center of the light beam and the hole.
In the method of detecting the position of the light beam for measuring the deviation from the center
The light source unit provided on one surface side of the target object.
Is provided on a flat detection means provided on the opposite side.
A light receiver for detecting the center of the light beam is provided around the center.
A light means is provided, and a plurality of different
On the line that extends radially
Providing a diffracted light detecting means for detecting the light beam,
Peak of diffracted light generated when passing through the opening of the object
By detecting the value, the position of the detection means is determined.
After that, using the detecting means,
An output characterized by measuring the deviation from the center of the opening.
Beam position detection method. 9. The diffracted light detecting means receives the light beam.
Primary generated when the target object passes through the opening
That it is configured to detect the peak value of the diffracted light
9. The method according to claim 8, wherein the position of the light beam is detected. 10. A predetermined central portion of said flat plate detecting means.
The light receiving means provided at the periphery is located at the center of the light beam.
Light receiving element divided into multiple equal areas for detecting
9. The light beam according to claim 8, wherein:
How to detect the position of the system 11. The flat plate detecting means is provided.
The diffracted light detecting means is located at a predetermined central portion of the flat detecting means.
In each of a plurality of different directions extending radially from
A position at a predetermined first distance from the center of the light detecting means
First diffracted light detection means, auxiliary light detection means,
Greater than the first distance of the first diffracted light detection means
A second diffracted light detector provided at a position separated by a second distance
11. The device according to claim 10, wherein an output means is provided.
Light beam position detection method. 12. Passing through the opening of the target object in advance
Peak value of the first-order diffracted light of the light beam
It has a first wavelength that can be detected by the first diffraction light detecting means.
The first reference light predetermined in advance and the object
Peak of the first order diffracted light of the light beam passing through the aperture of the body
Is detected by any of the second diffracted light detecting means.
Using a predetermined second reference light at a second wavelength such as
12. The position of a light beam according to claim 11, wherein the position of the light beam is used.
Detection method. 13. The second wavelength of the second reference light is
The first reference light is configured to be longer than the first wavelength.
13. The position of a light beam according to claim 12, wherein
Location detection method. 14. The method according to claim 14, wherein the first reference light is transmitted to the target object by the opening of the target object.
Passing through the hole to generate a first primary diffracted light,
The peak value of the intensity of the first primary diffracted light is equal to that of all the first
The flat plate detecting means is turned on so that it is detected by the folded light detecting means.
Moving and displacing in the plane formed by the flat plate detecting means.
Then, the second reference light is transmitted to the aperture of the target object.
To generate a second first-order diffracted light,
The peak value of the intensity of the first order diffracted light is
As described above, the plate-like detecting means is
Move or displace in the plane, or form a plane different from the plane
By moving and displacing three-dimensionally as
The flat plate detecting means is positioned.
14. The method for detecting the position of a light beam according to any one of 8 to 13. 15. A predetermined measuring light instead of the reference light.
By passing through the aperture of the target object,
The center of the zero-order diffracted light of the measurement light and the positioned flat plate
Difference from the center of the light receiving means provided at the center of the detecting means
The light beam according to claim 14, wherein a difference is detected.
Position detection method.