JP2001091212A - Displacement-measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement-measuring device having advantages of both one-point measurement type and scan-type arbitrarily switchable according to the use form, and to correct an error in the direction of height in each measurement point, in spite of the scan-type device and to accurately obtain the displacement amount without increase in the volume of correction data. SOLUTION: A displacement calculating means 21 calculates and outputs the displacement of a surface to be measured according to the output of a photodetecting element 6. A mode setting means 25 controls a light source 2 and a deflecting means to be switched to light beam have irradiated in one point to the surface to be measured or to scan the surface. A correction data creating means 26 generates correction data according to the moving amount output from a correcting machine 40 to detect errors in the displacement detecting direction at the time of a calibration mode and the displacement at that time and stores the data in a correction data storage means 28. In normal mode, a displacement correcting means 27 corrects the displacement according to the correction data and outputs the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement measuring apparatus for measuring a displacement of a measuring surface of a measuring object in a non-contact manner, and more particularly to a displacement measuring apparatus capable of changing a scanning state of a measuring light to perform various measurements. About.

[0002]

2. Description of the Related Art FIG. 8 is a side view showing a conventional one-point displacement measuring device. The device 50 irradiates a laser beam from the light source 51 to the measurement target surface 10a of the measurement target 10,
The image at the irradiation point P is converted into a light receiving element 5 by an imaging lens 53.
No. 4 light-receiving surface 54a. Thus, when the measurement object 10 moves in the height (Z direction) (when the object surface 10a is displaced), the irradiation point P moves to P ′ or P ″, and the light receiving surface of the light receiving element 54 correspondingly moves. The position of the imaging point K at 54a moves to K 'or K ". The light receiving element 54 outputs a detection signal corresponding to the position of the image forming point K, and can calculate and output a displacement amount of the target surface 10a of the measurement target 10 based on a change amount of this signal.

FIG. 9 is a perspective view showing a scanning displacement measuring device. This scanning displacement measuring device 60
Converts the laser beam output from the light source 61 into a deflection device 6
2, the light is deflected within a certain angle range.
The deflected laser beam is irradiated by the lens 63 on the target surface 10a of the measurement target 10 on the measurement table 11 as light whose optical axis moves in parallel. The laser beam at the irradiation point P is linearly reciprocated or one-way scanned with a predetermined width in the X direction, and the image of the irradiation point P is formed by a first cylindrical lens (cylindrical lens) 64 and a second cylindrical surface. An image is formed on the light receiving surface 66a of the light receiving element 66 by the lens 65. According to the above configuration, a detection signal corresponding to scanning of the target surface 10a of the measurement target object 10 is output from the light receiving element 66, and the displacement amount in the same X direction can be continuously measured.

According to such a scanning type device 60, there is an advantage that the displacement amount in the X direction can be measured at high speed without moving the device 60 or the object 10 to be measured. For example, the motor used to relatively move the measurement target 10 in the X direction using the one-point measurement type device 50 is extremely slow compared to the scanning speed of the deflecting device 62. It took time to measure the entire target surface 10a. In addition, the measurement is easily affected by the movement accuracy of the motor and cannot be measured at a fine pitch.

[0005]

However, in the scanning device 60, the scanning of the laser beam by the deflecting device 62 is performed at a high speed, so that the measuring light appears linear to human eyes. Since the actual scanning width is set wider than the effective scanning width (the range in the X direction that can be measured), the effective scanning width cannot be visually confirmed. As a result, the relative positioning between the device 60 and the measurement target 10 for measuring the measurement target 10 was troublesome.

Further, the scanning type device 60 is, for example, 200
Since the scanning is performed at a very high speed of 0 times / sec, the measurement processing system used in the one-point type device 50 cannot cope with this speed, and a special measurement processing system for the scanning type device 60 is required. Was. For example, analog time feed recorder, XY
A general-purpose measurement processing system such as a recorder cannot be used. As described above, the scanning device 60 is capable of high-speed measurement, but it cannot perform simple displacement measurement, which is an advantage of the one-point type.

By the way, in the scanning type device 60,
Although there are a plurality of linear measurement points P in the scanning direction X, it is necessary to correct the linearity of the displacement measurement amount at each of the measurement points P. That is, when the displacement of the reference plane is measured, the displacement of each of the plurality of scanned points is not uniform in the height direction (Z direction), and an error occurs. This is due to an error of the triangulation method, a focus accuracy and an assembly error of the optical system of the apparatus. In order to correct this error, it is necessary to store as many correction values as the number corresponding to the resolution in the height direction (Z direction) for each measurement point P. For example, 100 measurement points P in a scanning range of 30 mm in the X direction
And each measurement point P is 12 bits in the displacement direction (Z direction).
Assuming that it has a measurement resolution of (4096), data of a total of 40960 correction values obtained by multiplying these data is required, and the capacity of the storage means increases in order to store the data of the correction values. Become.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a displacement measuring device which has both advantages of a one-point measuring type and a scanning type and which can be arbitrarily switched according to a use mode. It is intended to provide. It is another object of the present invention to provide a displacement measuring device that can correct a height error at each measurement point while having a scanning type configuration, and can accurately obtain a displacement amount without increasing the volume of correction data. I have.

[0009]

In order to achieve the above object, a displacement measuring apparatus according to the present invention irradiates scanned light onto a surface to be measured to detect an image forming point formed on a light receiving surface of a light receiving element. In a displacement measurement device that measures a displacement amount of the measurement target surface in a non-contact manner based on a position, a light source that emits light for irradiating the measurement target surface, and a light that is emitted from the light source and the measurement target surface A deflecting unit that can be scanned in a predetermined direction, a displacement calculating unit that calculates and outputs a displacement amount of the measurement target surface based on a detection signal corresponding to a detection position of the imaging point output from the light receiving element; Scanning detection means for detecting the position of the irradiation point on the measurement target surface of the light scanned by the deflection means, and a state in which the light source and the deflection means are controlled to scan the light to be irradiated on the measurement target surface, or 1
Processing means for switching to a state of irradiating only a point, and processing means for controlling so that one point on the measurement target surface is irradiated with the light based on the position of the irradiation point of the light detected by the scanning detection means. It is characterized by having.

[0010] A plurality of condenser lenses having uniform imaging characteristics around the optical axis are arranged along the scanning direction of the irradiation point, and a condenser lens array for converging measurement light from the irradiation point; An imaging lens having uniform imaging characteristics around the optical axis is formed for each of a predetermined number of the condenser lenses along the scanning direction of the irradiation point, and the converged measurement light is applied to a light receiving surface of the light receiving element. An imaging lens array that emits light and forms an imaging point on the light receiving surface, and a light receiving element group having the light receiving element for each of the imaging lenses may be provided.

The apparatus further includes a compensator for relatively controlling the movement of the apparatus and the reference measurement target surface along the direction of detection of the displacement, and detecting the movement during the movement. A calibration mode for generating correction data based on a difference between the movement amount output from the compensator and the displacement amount output from the displacement calculation means, and the displacement amount output from the displacement calculation means during normal measurement. May be corrected using the correction data corresponding to the displacement amount.

A condenser lens array having a plurality of condenser lenses having uniform imaging characteristics around the optical axis arranged along the scanning direction of the irradiation point, and converging measurement light from the irradiation point; An imaging lens having uniform imaging characteristics around the optical axis is formed for each of a predetermined number of the condenser lenses along the scanning direction of the irradiation point, and the converged measurement light is applied to a light receiving surface of the light receiving element. An imaging lens array that emits light and forms an imaging point on the light receiving surface; and a light receiving element group that has the light receiving element for each of the imaging lenses. Correction data may be generated for each condenser lens of the lens array as a unit, and correction may be performed using the correction data for each condenser lens during normal measurement.

A plurality of condenser lenses having uniform imaging characteristics around the optical axis are arranged along the scanning direction of the irradiation point, and a condenser lens array for converging measurement light from the irradiation point; An imaging lens having uniform imaging characteristics around the optical axis is formed for each of a predetermined number of the condenser lenses along the scanning direction of the irradiation point, and the converged measurement light is applied to a light receiving surface of the light receiving element. An imaging lens array that emits light and forms an imaging point on the light receiving surface; and a light receiving element group having the light receiving element for each of the imaging lenses, wherein the processing unit performs the image formation in the calibration mode. The correction data may be generated for each imaging lens of the lens array as a unit, and the correction may be performed using the correction data for each imaging lens during normal measurement.

[0014] Further, a displacement measurement for irradiating the surface to be measured with scanned light and measuring a displacement of the surface to be measured in a non-contact manner based on a detection position of an imaging point formed on the light receiving surface of the light receiving element. A deflection unit configured to scan light emitted from a light source in a predetermined direction on the surface to be measured, and a scanning detection unit configured to detect a position of an irradiation point on the surface to be measured of the light scanned by the deflection unit. Based on a detection signal output from the light receiving element and corresponding to the detection position of the imaging point, a displacement calculating means for calculating and outputting a displacement amount of the surface to be measured, and A compensator that relatively controls the movement of the apparatus and the reference measurement target surface and detects a movement amount during the movement, and an error in a direction of detection of the displacement amount output from the displacement calculating unit is used as the displacement amount. Correct using the corresponding correction data Is intended to perform a physical, and detect when said scanning a desired point on the object surface based on the position of the irradiation point of the light detected by the scanning detector,
Processing means having a calibration mode for generating correction data based on a difference between the movement amount output from the corrector at the time of scanning the one point and the displacement amount output from the displacement calculating means. It is characterized by.

According to the above configuration, the switching at the time of the measurement
It is possible to select a one-point type that irradiates a single light beam to the measurement target surface 10a or a scanning type that scans. As described above, since the scanning on the apparatus side can be switched according to the usage mode, the one-point type can easily perform positioning and can use an inexpensive apparatus for recording the amount of displacement. In the scanning type, the amount of displacement of the surface to be measured can be measured at high speed in the scanning direction. Further, the error in the displacement amount detection direction of the device can be eliminated by calculating the correction data in the calibration mode and correcting the correction data at the time of measurement. This correction data can be corrected using the correction data at one irradiation point on the surface to be measured. Even when the apparatus is used in a scanning type, correction processing can be easily performed using the correction data.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] An embodiment of a displacement measuring apparatus and method according to the present invention will be described. FIG. 1 is a schematic perspective view of a displacement measuring device, and FIG. 2 is a side view of the same. As shown in the drawing, the displacement measuring device 1 measures the displacement of a measurement target surface 10a of a measurement target 10 placed on a measurement table 11 based on the principle of triangulation.

The light projecting system of the displacement measuring device 1 is roughly composed of a light source 2 such as a laser diode, a deflecting means 3 composed of a vibrating mirror and the like, and a lens 4. Light source 2
A laser beam having a predetermined wavelength (for example, 680 nm) is emitted to the deflecting unit 3. The deflecting means 3 deflects the incident laser light, and scans the laser light in a fixed stroke in the X direction in the figure. The deflecting means 3 is composed of, for example, a rotary galvanometer mirror, and reciprocally or one-way scans the laser light by continuously changing the angle of the mirror by rotation. In addition, as the deflecting means 3, a tuning fork mirror having a mirror attached to the tip of the tuning fork or a polygon mirror can be used. The lens 4 focuses the laser beams scanned by the deflection unit 3 so as to be parallel to each other,
The measurement target surface 10a of the measurement target 10 on the measurement table 11 is irradiated.

The lens array 5 is made of synthetic resin or glass so that a plurality (six in FIG. 1) of condenser lenses 5a to 5f having the same focal length f (for example, 20 mm) are arranged in a line. .

Each of the condenser lenses 5a to 5f has a width at least along the parallel direction shorter than the scanning width so that a plurality of condensing lenses are arranged within the scanning width (30 mm) of the projection beam emitted from the scanning optical system. It has a substantially rectangular outer shape (for example, 6 mm). Each of the condenser lenses 5a to 5f is a spherical focusing lens in which one or both surfaces orthogonal to the optical axis are formed in a spherical shape. A spherical focusing lens is a lens that can evenly focus light around its optical axis. The optical axes are integrated in a state where their side surfaces are in close contact with each other so as to be continuously arranged in a line on a line that is parallel and orthogonal to the optical axis. The lenses 5a to 5f may be lenses whose surfaces orthogonal to the optical axis are aspherical, as long as the lenses can be evenly focused around the optical axis with light.

The lens array 5 includes each of the condenser lenses 5a to 5a
The optical axis of f is disposed so as to intersect with the irradiation point P (movement trajectory PL) scanned on the surface 10a of the measurement object 10. Further, as shown in FIG. 2, the lens array 5 is arranged so that its longitudinal direction is parallel to the movement locus PL of the irradiation point P. The distance from the irradiation point P to the lens array 5 is arranged at a position that is substantially equal to the focal length f.

The imaging lens 7 is a spherical focusing lens having a diameter larger than the scanning width of the irradiation point P. Imaging lens 7
Focuses the beam from the lens array 5 and forms an image on the light receiving surface 6a of the light receiving element 6.

As shown in FIG. 1, the light receiving element (PSD) 6 has a vertically long light receiving surface 6a on which light reflected from the irradiation point P is imaged. The vertical direction of this light receiving element 6 (scanning direction P
Electrodes are provided at both ends in the direction perpendicular to L). From these electrodes, currents corresponding to the positions of the imaging points K are output as described above. That is, when the imaging point K is located at the center of the light receiving surface 6a, the same value of current is output from both ends of the light receiving element 6. When the imaging point K moves in the vertical direction, more current is output from the closer electrode, and less current is output from the farther electrode. As described above, the vertical direction of the light receiving surface 6a corresponds to the amount of displacement (the height direction Z). The scanning direction X corresponds to a lateral direction of the light receiving surface 6a. In addition,
The total value of the currents output from both electrodes is the same regardless of the position of the imaging point K.

As described above, each of the condenser lenses 5a to 5f has an optical axis parallel to each other, and is arranged in parallel on a straight line orthogonal to each optical axis at a position apart from the irradiation point by a focal distance. By configuring the array 5, the width of the light receiving surface 6a of the light receiving element 6 can be reduced, and a small light receiving element 6 having a fast response speed can be used. This also increases the scanning speed, improves the processing speed for the signal output of the light receiving element 6, and shortens the measurement time.

FIG. 3 is a block diagram showing the electrical configuration of the displacement measuring device. The displacement calculator 21 outputs a signal indicating the displacement of the measurement target 10 based on the output of the light receiving element 6. The displacement calculation processing in the displacement calculation means 21 converts current signals output from both electrodes of the light receiving element 6 into voltage signals, and then adds and subtracts each voltage signal. The subtracted signal value is divided by the added signal value, and a signal indicating the displacement is output to the processing unit 24.

The scanning start detecting means 22 is provided inside or outside the deflecting means 3. This scanning start detecting means 22
Outputs a single-pulse scanning start signal to the counting means 23 each time the scanning of the laser beam incident from the light source 2 is started. The counting means 23 is constituted by a counter, and receives a clock signal and a scanning start signal. The counting means 23 outputs a count value of the clock signal every time the scanning start signal is input. These scanning start detecting means 22 and counting means 23
Constitutes scanning detection means for detecting the scanning state of the laser beam.

The compensator 40 includes a movement amount detector 41, control means 42, and a movement stage. The compensator 40
The distance between the displacement measuring device 1 and the measurement target surface 10a is continuously measured with a predetermined resolution (for example, 12 bits: 4096 pieces of data). The corrector 40 operates in the calibration mode. The movement amount detector 41 is configured by a length measuring device or the like, and detects and outputs the position of the displacement measuring device 1 in the height direction (Z direction). The control unit 42 performs control to change the position of the displacement measuring device 1 in the height direction (Z direction). Then, the control means 42 outputs the movement amount in the height direction detected and output from the movement amount detector 41 at the time of the movement control to the correction data creating means 26.

The processing means 24 includes a mode setting means 25, a correction data creation means 26, a displacement correction means 27, and a correction value storage means 28. The mode setting means 25 roughly switches the operation state of the apparatus by operating an operation means (not shown) and switches between the calibration mode and the measurement mode. In the measurement mode, the scanning of the laser beam is switched between the one-point type and the scanning type. And each part is controlled according to these switching. The correction data creating means 26 creates correction data in the displacement direction (Z direction) at one irradiation point on the measurement object 10 in the calibration mode. At this time, the correction data is generated based on the movement amount in the height direction (Z direction) output from the corrector 40 and the signal input of the displacement amount output from the displacement calculating means 21, and the obtained correction value is obtained. The data is stored in the correction data storage means 28.

The correction value storage means 28 is configured using a ROM, a RAM, and the like. For example, a rewritable RO
The correction data is stored in a table format for each address corresponding to a plurality of height positions (Z-direction positions) in the calibration mode. In the measurement mode, the content stored in the ROM can be transferred to the RAM to increase the speed of reading.

The displacement correcting means 27 operates in the measurement mode and outputs a calibrated displacement signal. The displacement correcting means 26 reads out the correction data stored at the address associated with the displacement amount output from the displacement calculating means 21. Then, the displacement amount input from the displacement computing means 21 is subjected to a correction operation process based on the correction data, and a signal in which the displacement amount is corrected is output.

The mode setting means 25 controls the irradiation of the light beam so as to irradiate only one point (not to scan) in the calibration mode and when the one-point type is set in the measurement mode. . That is, at the time of these settings,
Control is performed such that the light beam is emitted only at one point in the scanning direction (X direction) (for example, at an intermediate position in the scanning direction). Specifically, the light source 2 is driven to emit light so that a light beam is emitted only when the count value from the counting means 23 reaches the one irradiation point.

The scanning switching control of the light beam in the measurement mode by the above configuration will be described. In the measurement mode, the scanning of the light beam can be switched to a one-point type or a scanning type by an operation switch or the like. When the scanning type is selected, the light from the light source 2 is scanned in a predetermined range by the deflecting means 3 and is irradiated on the measurement target surface 10a. When the device functions as a scanning type, the displacement of the measurement target surface 10a in the scanning direction (X direction) can be continuously measured by scanning with the light beam.

When the one-point type is selected, the light source 2 is driven to emit light intermittently at a predetermined cycle. At this time, the deflection means 3
Performs an operation of scanning the light beam within a predetermined range as in the case of the scanning type. That is, based on the scan start signal output from the scan start unit 22, the counting unit 23 counts the clock and drives the light source 2 to emit light only when the light reaches the above-mentioned one irradiation point. . Thus, the light beam is irradiated to the same irradiation point P on the measurement target surface 10a at every predetermined cycle corresponding to each scan, and the displacement of the irradiation point P can be measured.

The functioning of the apparatus as a one-point measurement type enables a displacement signal to be output to a general-purpose analog time-feed recorder or an XY recorder. The displacement can be measured and recorded. In addition, since the light beam is irradiated only to one irradiation point P which is always the same, the irradiation position of the light beam on the measurement object 10 can be visually determined.

In the above description, an example in which the deflecting means 3 operates continuously when the apparatus functions as a one-point type is described, but the present invention is not limited to this. For example, deflection means 3
Is stopped and fixedly held at an intermediate position, so that a light beam from the light source 2 can be continuously applied to one point on the measurement target surface 10a. At this time, it is desirable that the angle of deflection by the deflection means 3 can be adjusted so that the irradiation point has an arbitrary angle.

Next, the calibration mode of the above device will be described. FIG. 4 is a flowchart showing the processing contents in the calibration mode. At the time of calibration, the measurement target 10 serving as a reference is placed on the measurement table 11. For example, measurement target surface 10
a uses a block gauge having a predetermined accuracy.

Then, the displacement measuring device 1 irradiates the light beam to one irradiation point P on the measurement target surface 10a (SP
1). That is, the mode setting means 25 controls the light source 2 in the same manner as in the case of one-point measurement of the apparatus, and controls
The point is irradiated with a light beam. Next, the distance between the displacement measuring device 1 and the measurement target surface 10a is varied by the corrector 40. Specifically, the displacement measuring device 1 or the measuring table 11
Is relatively continuously moved in the height direction Z (SP2). Thereby, the movement amount detector 41 detects and outputs the movement amount in the height direction. At the same time, the displacement calculating means 21
A predetermined displacement is output in response to this movement.

The correction data creation means 26 acquires these signals of the movement amount and the displacement amount (SP3). Then, the difference between the two is obtained by subtracting the amount of displacement from the obtained amount of movement, and this difference is used as correction data (SP4). FIG.
FIG. 4 is a diagram for explaining an error that occurs in a direction in which a displacement amount is detected. As shown in the figure, it is assumed that the movement amount output from the corrector 40 has an accuracy proportional to the true displacement amount. On the other hand, the displacement amount actually output from the displacement measuring device 1 is a value that is deviated in the height direction Z compared to the movement amount. This deviation corresponds to the error component of the device as described above.

Therefore, the correction data creation means 26
Based on the movement amount, a difference from the displacement amount at each predetermined movement amount is calculated as correction data. Here, the compensator 40 is configured to repeatedly stop the displacement measuring device 1 continuously in the height direction Z or at a plurality of measurement height positions. The correction data creating means 26 executes the correction data creating process continuously or in conjunction with the movement control of the corrector 40, or at each stop at a plurality of measurement height positions. This is due to the movement accuracy of the corrector 40 and the detection accuracy of the displacement measuring device 1 in the height direction Z. The resolution accuracy of the correction data in the height direction Z is 12 bits (4096) as described above. are doing.

The correction data thus obtained is stored in the correction data storage means 28 (SP5). R
The address space composed of the OM or the like is in a table format, and each correction data (displacement amount and correction value before correction) is stored and held at an address for each measurement height position. Here, when the resolution accuracy is 12 bits, the storage capacity of the correction data storage unit 28 is 8 corresponding to 4096 words.
192 bytes. Note that the correction data creation means 26
If the resolution of the data is reduced, 256 data can be used for the 8-bit arithmetic processing, thereby saving the capacity. Even in this case, in the measurement mode, a correction value having a resolution of 12 bits can be created by interpolation calculation.

In the above calibration, the displacement measuring device 1 is configured to irradiate a light beam to one point on the surface 10a to be measured. However, the present invention is not limited to this. That is, the light beam may be kept scanning. In this case, the correction data creation unit 26 is configured to acquire the movement amount and the displacement amount at the time when the light beam reaches one irradiation point by the counting of the counting unit 23.

Next, a description will be given of a displacement amount correction process using the correction data in the measurement mode. The irradiation of the light beam on the measurement target surface 10a in the measurement mode is switched to the one-point type or the scanning type as described above. First, the displacement amount correction processing in the one-point type will be described. The light beam is emitted from the measurement object 10a as described above.
Is formed, and the position of the imaging point on the light receiving surface 6a of the light receiving element 6 is changed in accordance with the displacement of the measurement target surface 10a, and the displacement calculating means 21 outputs a signal of the displacement. You.

This displacement amount is corrected by the displacement correcting means 27. The displacement correcting means 27 is provided in the correction data storing means 2.
8 is read out from the correction data. That is, a correction value associated with this displacement amount is obtained. Then, a signal of the corrected displacement amount obtained by subtracting the correction value from the measured displacement amount is output. By this correction, the displacement amount is corrected so as to be located on a straight line that is proportional to the movement amount (height direction Z), as shown in FIG.

Next, in the displacement amount correction processing when the displacement measuring device 1 is used as a scanning type, the displacement amount is basically corrected by the same processing contents as in the case of the one-point type.
Here, even if the light beam is scanned in the X direction, it does not cause an error in the height direction Z. That is, the light receiving element 6 has no sensitivity in the scanning direction X on the light receiving surface 6a. That is, even if the imaging point moves in the scanning direction on the light receiving surface 6a, the detection of the displacement amount does not change before and after the movement.

Therefore, when the apparatus is used as a scanning type, it can be corrected using the correction data at any measurement point in the scanning direction X. At this time, similarly to the above-described correction processing, the displacement correction unit 27 may execute a correction operation based on the correction data corresponding to the input displacement amount.

In the above embodiment, the configuration using the lens array 5 for the light receiving system has been described as an example, but the present invention is not limited to this. For example, a conventional cylindrical lens 6 shown in FIG.
Also in the configuration using No. 4, it is possible to similarly correct the error of the displacement amount with respect to Z in the height direction.

In the above embodiment, the correction data is created by the processing means 24 of the displacement measuring device 1.
It is also possible to adopt a configuration in which the correction data is created on the side of the control means 42 and stored in the correction data storage means 28.

[Second Embodiment] Next, a second embodiment of the present invention will be described. In the present embodiment, a displacement measuring device 30 having a light receiving system as shown in FIGS. 10 and 11 is used. The electrical configuration is the same as in the first embodiment. The light receiving system of the displacement measuring device 30 has an imaging lens array FA in which the imaging lenses 7 used in the first embodiment are arranged in an array.

The light receiving system comprises a condenser lens array CA, an imaging lens array FA, and a light receiving element group P. The condenser lens array CA has the same configuration as the lens array 5 shown in the first embodiment, and has the same focal length f1
A plurality (n) of condenser lenses CA1 to CAn (for example, 20 mm) are formed of synthetic resin or glass so as to be arranged in a line.

Each of the condensing lenses CA1 to CAn is arranged at least in the parallel direction (scanning direction) so that several n are arranged within the scanning width (for example, 30 mm) of the irradiation light irradiated from the light projecting system. Has a substantially rectangular outer shape (for example, 5 mm) whose width d is shorter than the scanning width of the irradiation light (for example, 30 mm). Each of the condenser lenses CA1 to CAn is a lens having a surface orthogonal to the optical axis formed in a spherical shape. That is, each of the condenser lens units CA1 to CAn is a lens that can uniformly narrow down light around its optical axis. The optical axes are integrated in a state where their side surfaces are in close contact with each other so as to be continuously arranged in a line on a line that is parallel and orthogonal to the optical axis.

The condenser lens array CA is composed of the respective condenser lenses C
The optical axes of A1 to CAn are arranged so as to intersect with the irradiation point P (movement trajectory PL) scanned on the surface 10a of the measurement object 10. The condenser lens array CA is disposed at a position away from the irradiation point P (movement trajectory PL) by a focal distance f1.

The imaging lens array FA is a lens array in which a plurality (m) of imaging lenses FA1 to FAm are arranged in an array in the scanning direction, like the condenser lens array CA. It should be noted that there are two in FIG. 10 due to drawing restrictions. Each of the imaging lens units FA1 to FAm is a lens capable of uniformly narrowing incident light around its optical axis. The imaging lenses FA1 to FAm are integrated in a state where their side surfaces are in close contact with each other such that their optical axes are parallel to each other and are continuously arranged in a line perpendicular to the optical axis.
Each of the imaging lenses FA1 to FAm is opposed to each other by a predetermined number of condenser lenses (six in FIG. 11) CA1 to CA6. The imaging lens array FA converges the measurement light from the condenser lens array CA and emits it to the light receiving element group PA.

The light receiving element group PA includes imaging lenses FA1 to FA
It is composed of the same number (m) of light receiving elements PA1 to PAm as Am. The light receiving elements PA1 to PAm correspond to the imaging lenses FA1 to FAm, respectively, and are arranged at positions apart from the focal length f2.

As shown in FIGS. 10 and 11, each of the light receiving elements PA1 to PAm has a light receiving surface PAa on which the measuring light from the irradiation point P is imaged. Electrodes are provided on both longitudinal edges of each of the light receiving elements PA1 to PAm. From these electrodes, currents corresponding to the positions of the imaging points K are output.

According to the above configuration, each of the imaging lenses FA1 to FA1
FAm and the F number of the condenser lenses CA1 to CAn can be kept constant, and displacement measurement in a wider area can be performed without changing the amount of received light and both focal lengths. That is, the scanning width of the surface to be measured can be increased.

In the optical system having the above configuration, the scanning of the light beam in the measurement mode can be arbitrarily switched between the one-point type and the scanning type. Further, the processing means 24 can also execute the processing shown in FIG. 4 to create the correction data in the processing for creating the correction data in the calibration mode.

This correction data creation is performed in step SP1 at 1
The irradiation point of the point can be set to each of the condenser lenses CA1 to CAn constituting the condenser lens array CA.
Thereby, each condenser lens CA1 is executed by executing SP2 to SP5.
.. CAn. At this time, the position of the irradiation point is determined by counting the scanning start signal output from the scanning start means 22 by the counting means 23, and thereby the condensing lens CA
Scan positions on 1 to CAn can be detected.

In the measurement mode, the processing means 24 similarly counts the light from the condensing lens CA1 by the counting of the counting means 23.
ＣＡCAn is detected, and corresponding correction data for each of the condensing lenses CA1 に CAn at this scanning position is read to correct the displacement amount. In addition to the configuration for creating correction data for each of the condenser lenses CA1 to CAn,
Correction data can also be created for each of the imaging lenses FA1 to FAn.

The configuration in which correction data is created and corrected for each lens array unit as described above has the following functions and effects. Focal length f for each of the condenser lenses CA1 to CAn
1 and the inclination of the linearity due to the variation of the focal length f2 for each of the imaging lenses FA1 to FAn is different. Therefore, this can be improved by creating and correcting the correction data for each lens constituting the array.

In addition, when adjusting the light receiving system as a lens unit of the imaging lenses FA1 to FAn, there is also a variation in linearity. In addition, the light receiving element PA itself has a variation in linearity. Therefore, the correction data is created for each lens and corrected, so that the accuracy of the displacement measurement can be further improved due to these effects. Note that the correction data is the number CAn of the condenser lenses CA at the maximum, and does not cause an increase in the data amount of the correction data.

[0060]

According to the present invention, it is possible to selectively switch between a state in which light to be irradiated on the surface to be measured is scanned and a state in which light is irradiated to one point. This allows a single device to be adapted for a variety of uses. When used as a one-point type, since a light beam is applied to one point on the surface to be measured, positioning between the apparatus and the object to be measured can be performed easily. Further, the displacement can be output to a simple recorder conventionally used, such as an analog time feed recorder, so that simple measurement can be performed. on the other hand,
When used as a scanning type, the displacement amount of the measurement target surface can be measured at high speed along the scanning direction.

In order to set the irradiation point of the light beam on the surface to be measured to one point when using the one-point type,
A configuration in which light emission driving is performed only when the light source irradiates one point while the scanning by the deflecting unit is continued, or a configuration in which the light source is continuously driven to emit light and stop control is performed so that the scanning by the deflecting unit irradiates one point. It can be made to function as a one-point type with a scanning type basic configuration,
Both functions can be easily achieved with a single device.

In the case where the condenser lens and the imaging lens are constituted by a plurality of arrays, in addition to the above-mentioned effects, the measuring time can be shortened by using a small and highly responsive light-receiving element. The measurement can be performed with the scanning width enlarged. Further, it is possible to measure the displacement of a wide area without changing the focal length while keeping the F number of each condenser lens and imaging lens constant.

An error in the direction of detection of the displacement amount of the apparatus can be corrected by executing the calibration mode. In the calibration mode, the difference between the amount of movement when the apparatus and the reference measurement target surface are relatively moved along the direction of detection of the amount of displacement using the compensator and the amount of displacement output from the displacement calculating means. The correction data is created based on. This makes it possible to easily and accurately correct an error in the detection direction of the displacement amount output from the displacement calculating means during the normal measurement using the correction data. Further, the displacement amount can be corrected using the same correction data in both cases where the device functions as a one-point type and a scanning type.

Furthermore, if the correction data is created and corrected for each lens unit of the condenser lens or the imaging lens, the dispersion of the focal length of each lens array, the dispersion of the linearity of a plurality of light receiving elements provided, and the Variations in adjustment for each light receiving system using the image lens as a unit can be corrected, so that the measurement time can be shortened and displacement measurement in a wide area can be performed with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a first embodiment of a displacement measuring device of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a block diagram showing an electrical configuration of the displacement measuring device.

FIG. 4 is a flowchart showing processing contents in a calibration mode.

FIG. 5 is a diagram for explaining an error that occurs in a displacement amount detection direction.

FIG. 6 is a perspective view showing a configuration of a second embodiment of the present invention.

FIG. 7 is a top view of the same.

FIG. 8 is a side view showing a conventional one-point displacement measuring device.

FIG. 9 is a perspective view showing a conventional scanning displacement measuring device.

[Explanation of symbols]

1, 30 displacement measuring device, 2 light source, 3 deflecting means, 4
... Lens, 5, CA ... Lens array, 6 ... Light receiving element, 6
a: light receiving surface, 7: imaging lens, 10: object to be measured, 10
a: surface to be measured, 11: measuring table, 21: displacement calculating means,
22: scanning start detecting means, 23: counting means, 24: processing means, 25: mode setting means, 26: correction data creating means, 27: displacement correcting means, 28: correction data storage means,
40: Corrector, 41: Moving amount detector, 42: Control means,
FA: imaging lens array.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuki Nagatsuka 5-10-27 Minamiazabu, Minato-ku, Tokyo Anritsu Corporation (72) Inventor Atsuro Tanuma 5-10-27 Minamiazabu, Minato-ku, Tokyo KK Corporation F term (reference) 2F065 AA02 BB13 DD03 DD07 EE11 FF01 FF09 GG04 GG07 HH04 JJ03 JJ16 JJ26 LL08 LL10 LL13 LL14 QQ23 QQ24 QQ51 2F075 AA08 EE12 EE15 EE16

Claims (6)

[Claims] 1. A displacement measurement method for irradiating a light to be scanned onto a surface to be measured and measuring a displacement of the surface to be measured in a non-contact manner based on a detection position of an imaging point formed on a light receiving surface of a light receiving element. In the apparatus, a light source that emits light for irradiating the measurement target surface, a deflection unit that can scan light emitted from the light source in a predetermined direction on the measurement target surface, and output from the light receiving element Based on a detection signal corresponding to the detection position of the imaging point, a displacement calculation unit that calculates and outputs a displacement amount of the measurement target surface; and a position of an irradiation point on the measurement target surface of light scanned by the deflection unit. Scanning detecting means for detecting the light source and the deflecting means, and switching to a state of scanning the light to irradiate the surface to be measured, or a state of irradiating only one point, which is detected by the scanning detecting means. Light irradiation Displacement measuring apparatus wherein the light to a point on the object surface based on the position of characterized by comprising a processing means for controlling so as to be irradiated. 2. A condensing lens array in which a plurality of condensing lenses having uniform imaging characteristics around an optical axis are arranged along a scanning direction of the irradiation point, and converge measurement light from the irradiation point; An imaging lens having uniform imaging characteristics around the optical axis is formed for each of a predetermined number of the condenser lenses along the scanning direction of the irradiation point, and the converged measurement light is applied to a light receiving surface of the light receiving element. The displacement measuring device according to claim 1, further comprising: an imaging lens array that emits light and forms an image point on the light receiving surface; and a light receiving element group having the light receiving element for each of the imaging lenses. 3. A compensator that relatively controls movement of the apparatus and a reference measurement target surface along the direction of detection of the displacement, and detects a movement during the movement. The movement amount output from the compensator,
A calibration mode for generating correction data based on a difference between the displacement amounts output from the displacement calculating means, and in a normal measurement, an error in a detection direction of the displacement amount output from the displacement calculating means corresponds to the displacement amount. The displacement measuring device according to claim 1, wherein the displacement is measured using the correction data. 4. A condenser lens array having a plurality of condenser lenses having uniform imaging characteristics around an optical axis arranged along a scanning direction of the irradiation point, and converging measurement light from the irradiation point. An imaging lens having uniform imaging characteristics around the optical axis is formed for each of a predetermined number of the condenser lenses along the scanning direction of the irradiation point, and the converged measurement light is applied to a light receiving surface of the light receiving element. An imaging lens array that emits light and forms an imaging point on the light receiving surface; and a light receiving element group having the light receiving element for each of the imaging lenses. Generate correction data for each condenser lens of the lens array as a unit,
4. The displacement measuring apparatus according to claim 3, wherein at the time of normal measurement, the correction is performed using the correction data for each condenser lens. 5. A condensing lens array in which a plurality of condensing lenses having uniform imaging characteristics around an optical axis are arranged along a scanning direction of the irradiation point, and converge measurement light from the irradiation point. An imaging lens having uniform imaging characteristics around the optical axis is formed for each of a predetermined number of the condenser lenses along the scanning direction of the irradiation point, and the converged measurement light is applied to a light receiving surface of the light receiving element. An imaging lens array that emits light and forms an imaging point on the light receiving surface; and a light receiving element group having the light receiving element for each of the imaging lenses. The processing unit performs the image formation in the calibration mode. Generate correction data for each imaging lens of the lens array as a unit,
4. The displacement measuring device according to claim 3, wherein a correction is performed using the correction data for each of the imaging lenses during a normal measurement. 6. Displacement measurement for irradiating scanning light onto a measurement target surface and non-contactly measuring a displacement amount of the measurement target surface based on a detection position of an imaging point formed on a light receiving surface of a light receiving element. In the apparatus, a deflecting unit that scans light emitted from a light source on the measurement target surface in a predetermined direction, and a scanning detection unit that detects a position of an irradiation point on the measurement target surface of the light scanned by the deflection unit A displacement calculating unit that calculates and outputs a displacement amount of the measurement target surface based on a detection signal corresponding to a detection position of the imaging point output from the light receiving element; and A compensator that relatively controls the movement of the device and the reference measurement target surface, and detects a movement amount during the movement, and an error in a direction of detection of the displacement amount output from the displacement calculating unit is used as the displacement amount. Correction using the corresponding correction data Detecting a timing for scanning a desired point on the measurement target surface based on the position of the irradiation point of the light detected by the scanning detection means, and detecting the timing for scanning the one point. A displacement measuring device comprising: a processing unit having a calibration mode for generating correction data based on a difference between a displacement amount output from a corrector and a displacement amount output from the displacement calculating unit.