JP3513945B2 - Optical displacement measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object for a reference plane.
Optical displacement measuring device for measuring surface displacement
It is. [0002] 2. Description of the Related Art Conventionally, an optical displacement measuring apparatus of this kind has been known.
As a technique described in Japanese Patent Laid-Open No. 1-245103,
The art is known. This optical displacement measuring deviceIn FIG.
As shown, projections such as semiconductor lasers and light emitting diodes
The light from the light emitting element 31 and the light
The light projecting means 3 is formed by the light projecting optical system 32 that forms the beam.
And the light beam is deflected by the scanning mirror 33.object
body30Irradiates the surface of the object and the light beam30Table
Light spot formed on the surfaceIn the X directionScan. Light
The diffusely reflected light from the surface of the
The distance in the Z direction to the object 30 is obtained by being illuminated.
Can be That is,Light receiving means4Is the light receiving optical system42Through
Light emitting spot41Image on the light-receiving surface of
Forming an imaging spot, KnotDepending on the position of the image spotReceiving
From optical element 41Using the output position signalFor arithmetic means
InBy performing calculations based on triangulation,
Reference plane to the projected spot at the scanning position (general
At the time when an imaging spot is formed in the center of the position signal
Based on the measurement condition, the distance when this measurement condition is satisfied
The plane located at a distance is used as the reference plane.)
It is configured to determine.Scanning position of projection spot
Is one of the light beams traveling from the scanning mirror 33 to the object 30.
The half mirror 34 that reflects the part and the half mirror 34
PS for detecting the scanning position of reflected light in the X direction
It can be obtained by using the position sensor 35 composed of D or the like.
Wear.Therefore, the displacement of the object surface and the scanning position of the light beam
By matching the position to the
Displacement can be measured.Paraphrase
And the light of the light beam from the light projecting means 3 as shown in FIG.
If the position of the object 30 on the axis changes to A, B, C,
On the light receiving surface of the optical element 41, the position of the image spot is
A, b, and c move within the frame, so position detection in the plane of the figure
It is possible to use a one-dimensional position sensor capable of
With this, an image spot is formed based on the output of the light receiving element 41.
Is detected, the light receiving optical system 42 and the scanning mirror 33 are detected.
To the object 30 by triangulation with the distance to
The distance at can be determined. The displacement is continuously measured at each position of the projection spot.
A line that scans the projected spot without measurement (ie, scanning
Line) and sample at many measurement points on the scan line.
It is common to measure. The measurement point is
A certain time interval in the scanning direction or
It is determined so as to have a fixed distance interval. Described in the above publication
In the device described above, the difference in displacement between each pair of adjacent measurement points is calculated.
For the point sequence of the measurement points arranged in order of scanning time,
If the sign of the difference is the same, the absolute value of the difference
And the measurement point at which the integrated value becomes the maximum
The position of the step on the object surface based on the scanning position and displacement of the difference point
Are looking for placement and dimensions. [0004] The light receiving means4
Light-receiving element used for41Is only the position information of the imaging spot
, But also information on the amount of received light. Sand
And this kind of light receiving element41Has a PSD and two photos
An element or diode with diodes arranged in the direction of movement of the imaging spot
Uses various elements such as photodiode arrays and CCDs
Element with PSD and two photodiodes
In the child, a pair whose ratio is determined according to the position of the imaging spot
Output signals, and use photodiode arrays or CCDs
Also outputs a signal corresponding to the position of the imaging spot. However
And any light receiving element41The signal value that is also output is the amount of received light
Increase or decrease according to. Now, depending on the position of the imaging spot
An element that outputs a pair of signals whose ratio is determined
Value is I₁, I_Two, The displacement is compensated using both signals.
To find the corresponding value, (I₁-I_Two) / (I₁+
I_Two) Or the need for operations similar to this
Are known. As is clear from this calculation, the denominator
(I₁+ I_Two) Is the light receiving element41Is the total amount of light received at
If this value is not determined accurately, the displacement must be determined accurately.
Can not. In addition, each signal I₁, I_TwoToo much about
If it is too small, the range that can be calculated by the calculation means (for example,
For example, deviating from the dynamic range of the amplifier circuit)
The position cannot be determined accurately. However, the object30Surface shape and material
Therefore, the object 30 may be out of the measurable range of the received light amount.
It may be difficult to accurately determine the surface displacement of
You. The present invention has been made in view of the above circumstances.
The goal is to be correct even if the amount of received light is too large or too small.
Optics that can provide possible measurement results
An object of the present invention is to provide a displacement measuring device. [0006] [Means for Solving the Problems]The present inventionThe surface of the object
Scan the light beam on the surface of the object so that the projection spot moves.
Light emitting means for inspecting and projecting light, and receiving light
Imaging on the light receiving surface of the light receiving element through the optical system
Light receiving that outputs a position signal containing information on the position of the spot
Means and an object to a reference plane based on the output of the light receiving means.
Measurement of body surface displacement corresponding to the scanning position of the light beam
Optical displacement measuring device having a calculation means for obtaining a resultTo
When the amount of light received by the light receiving means is out of the specified range
In addition, the scanning position of the light beam obtained immediately before the value falls outside the above range
And displacement as the scanning position and displacement of the measurement result.
The measurement data correction unit is provided. [0007] [0008] [0009] [Action]According to the configuration of the present invention,Too much or too much
Become smallPart existsIfThe light receivingQuantitative threshold
The displacement just before crossingI do.Generally speaking,
If the shape is not complicated, the amount of received light will be excessive
When the specular reflected light of the projection beam is incident on the
If the amount of received light is too small, there is a dent on the surface of the object.
When part of the projection spot enters the blind spot of the light receiving element
Or a range outside the measurable displacement. So
Here, these shape changes are ignored,
By substituting the displacement just before the change,
Measurement results that are relatively close to changes in the shape of the object by suppressing
They are trying to get results. [0010]The displacementNot just the scanning position
ToFrom the light receivingChange the shape so that the amount is too large or too small
Measurement will not be performed in the part where
The ability to obtain measurement results only for measurable parts
TonanaYou. [0011] 【Example】(Basic configuration) FIG. 1 shows the optical displacement measurement of the present invention.Basic configuration of the deviceSo
The gist of the present invention is that the displacement sensor shown in FIG.
And the measurement data correction unit 12.This example
Now, a displacement meter that measures the displacement of the object surface and outputs the measured value
The shape to be measured by the measuring unit 1 and the displacement measuring unit 1
The processing setting unit 2 for displaying measurement values is set to be separable.
There is. A displacement measuring unit 1 applies a light beam to the surface of an object.
A light projection spot formed on the object surface by the light beam
The object surface over the trajectory of the projected spot.
Displacement with respect to the reference plane corresponds to the scanning position of the projection spot
A displacement sensor 11 to be attached and detected. This displacement sensor
The sensor 11 is a displacement sensor on a line set on the surface of the object.
Distance to 11 (or displacement with respect to the reference plane)
And can be output in association with the position on the line
Anything is fine,This exampleThen, Japanese Patent Application No. 5-33
No. 758, the displacement sensor 11 is used.
You. This displacement sensor 11 has been described as a conventional technique.
It is similar to the one described above.
A laser light source or light emitting diode is used as the light source
And a collimated lens
Deflecting device, such as a galvanometer mirror, that forms a light beam
By scanning the light beam with the
The light emitting means is configured to scan the formed light spot.
It has been done. Also, the direction different from the light beam irradiation direction
Through a light-receiving optical system consisting of a convergent lens with an optical axis of
The image of the projected spot can be used as a PSD or photodiode array.
Focusing on the light receiving surface of any light receiving element as an image spot
Light receiving means is provided. Here, the light receiving element extends to the surface of the object.
Position in the direction in which the imaging spot moves according to the distance of
It may be a one-dimensional one that can detect the position. This receiving
The output of the optical element is the amount of light received along with the position information of the imaging spot.
It also contains information about However, in the displacement sensor 1, the imaging spot
Imaging spots output from the light-receiving element corresponding to the
Position of the light beam, the projection direction of the light beam and the optical axis of the light receiving lens.
Angle, the distance between the extension of the light beam and the center of the receiving lens,
Triangulation based on the distance between the receiving lens and the receiving element
By applying, the object table can be displayed by the built-in arithmetic means.
Find the distance to the surface. Also, the scanning position of the projection spot
Halfway between the deflector and the object surface to detect
In addition to providing a beam splitter consisting of a mirror,
Beam splitter separates light beam from object surface
A light receiving element provided separately with the light beam is provided. Sand
The scanning position of the projected spot is determined by the output of the light receiving element.
The position is detected. The scanning position of the projected spot is deflected
Obtained from the deflection angle of the light beam in the drive system of the device
You may do so. Here, PSD is used as the light receiving element.
The ratio of the signal value is determined according to the position of the imaging spot.
If two outputs are obtained, both signals
Is divided by the sum of the two signals, and the result of the division is received.
The distance from the output of the optical element to the surface of the object and the projection spot
It will correspond to the scanning position. Displacement sensor 1 described above
1 is an example, the structure of this type of displacement sensor 11 is shown.
Configuration is well known. By the way, in the displacement measuring section 1, the displacement
The output value of the sensor 11 is sampled within the scanning range of the projection spot.
To obtain a plurality of measured values.
Now, let the projection spot be on one straight line (called a scanning line).
Scan direction, the scanning line direction is the X direction,
The direction of measurement of the displacement at the sensor 11 is defined as the Z direction. Displacement sensor
11 is the coordinates (X_i, Z_i) Is output (i =
1, 2,...), These coordinates are input to the measurement data correction unit 12.
Is forced. The measurement data correction unit 12 includes a displacement sensor 11
If the amount of light received by the light receiving means provided in the
Substitute the measurement result just before it becomes excessive. That is, the object
The surface has a displacement on the scanning line as shown in FIG.
At this time, during the measurement as shown in FIG.
It is assumed that the amount of received light has become excessive at a part of. Where
To determine whether the light amount is large or not, a threshold value Tu is set for the amount of received light.
If it exceeds, it is determined that the amount of received light is excessive. Like this
In places where the amount of light is excessive, the displacement sensor 11
The value in the Z direction of the output coordinates (see FIG. 2C)
Is unreliable and the measurement results vary. There
So, as described above, in places where the amount of received light is excessive
By substituting the value immediately before the received light amount becomes excessive,
As shown in 2 (d), the measured values before and after the received light amount becomes excessive
The result is a tied shape that results in relatively good measurement results.
Can be. Light reception by the light receiving means provided in the displacement sensor 11
The same applies to the case where the light amount is too small.
Substitute with the measurement result just before. That is, the object surface runs
On the line of sight, there is a displacement as shown in FIG.
At this time, as shown in FIG.
If the amount of received light is too small at the place (the amount of received light
At that point, the output from the displacement sensor 11
Of the coordinates (see FIG. 3C) in the Z direction.
By substituting the value immediately before the light quantity becomes too small, FIG.
As shown in (d), the measured values before and after the received light amount becomes too small are calculated.
Shape and provide relatively good measurement results.
You. The measured data in the Z direction is measured by the measured data corrector 12.
The corrected coordinates are input to the change point recognition unit 13 and measured.
It can be regarded as a boundary such as a step on the object surface from a series of fixed points
Change point is detected. Change points are detected as follows
Is done. First, the point sequence of the measurement points arranged in the scanning order is described.
And the difference DZ in the Z direction at each adjacent measurement point_i(= Z
_{i + 1}-Z_i). Here, the object surface is almost flat
If the distance to the object surface is almost constant, the difference DZ
_iIs almost 0, but if there is a step on the surface of the object,
Minute DZ_iWill increase or decrease. So, positive
Threshold and difference DZ appropriately set for both negative_iRelationship with
Calculated and the difference DZ_iIs within the range of both thresholds,
When the value changes outside the range of the threshold value, the measurement point (X_i,
Z_i) Is a change point. Further, a sequence of measurement points is sequentially obtained.
Difference DZ_iWhere the increasing or decreasing trend of
If the difference DZ_iAnd the difference DZ_i-1(= Z_i-Z
_i-1) Are out of the range of both thresholds and are positive / negative
Are the same sign, the difference DZ_iThe absolute value of the previous difference
Minute DZ_i-1To the absolute value of. In this way, the difference
DZ_iIs within the range of both thresholds or the sign is inverted
Difference DZ up to_iContinue adding the absolute value of
Measurement point (X_i, Z_i) Is a change point. Next, based on the change point, the operation point recognition unit 14
The calculation point used for the measurement of the shape dimension is separately obtained by. Calculation point
Is selected from any of the following. below
In the description of the method, the point sequence of the measurement points is arranged in order from the left,
The positive direction in the Z direction is the direction in which the distance to the displacement sensor 11 is approaching.
Is shown.   When corners are formed on the object surface (B) The distance from the displacement sensor 11 changes from a substantially constant state.
Gradually approaching the position sensor 11 and then gradually moving away
Finally, the distance from the displacement sensor 11 becomes substantially constant again.
In this case, four change points are obtained for the sequence of measurement points.
It is. Here, since the corner is detected, the corner is at the intersection of the two straight lines.
Assuming that there are four change points, two
Assume the end of the line. So the two changes on the left
Find a straight line passing through the point and a straight line passing through the two change points on the right.
Therefore, the intersection of both straight lines is set as the calculation point. (B) The distance from the displacement sensor 11 is almost constant
Gradually approaches the displacement sensor 11 from
When the distance from the position sensor 11 becomes substantially constant,-
As in (a), four change points are obtained for the point sequence of the measurement points.
can get. Here, one straight line sandwiching the corner is the displacement sensor 1
1 is almost constant, so
By averaging the coordinates in the Z direction of the two change points on the right
A straight line can be determined. For the other straight line
-As in (a), use a straight line connecting the two left transition points.
I have. The intersection of the two straight lines obtained in this way is calculated
And A trapezoidal projection is formed on the surface of the object.
If In this case, for each straight line forming the protrusion,
Instead of finding one end point,
Not one at each corner between two points and two points at both ends of the tip edge of the protrusion
To get two changes. Calculation point obtained by this method
Is the dimension of the projection in the Z direction (the dimension of the projection
Is effective when seeking the law. (A) -A. Right and left rising parts of the protrusion
In order to find the operation point at,
Take out a fixed number of measurement points, and Z direction of the taken out measurement points
The first straight line is obtained by averaging the coordinates of. The performance you want
The calculation point is a point on the first straight line, next to the leftmost change point
Has the X coordinate of the measurement point. Also, to the right of the rightmost transition point
A predetermined number of measurement points, and Z of the extracted measurement points
The coordinates of the directions are averaged to obtain a second straight line. Required operation
The point is a point on the second straight line, right next to the rightmost change point
Has the X coordinate of the measurement point. For the X coordinate, the difference D
Z_i(Ie, at the leftmost change point)
If the change point at the right end, the left)
Take out the number of measurement points, and take the position of the taken out measurement point in the X direction.
The average value of the target can also be used. (A) -B. For the leading edge of the protrusion,
Average the X and Z coordinates of the two transition points between them, respectively
The point of the coordinate set is the calculation point. Therefore, this operation point is
It will be set near the center of the tip edge of the protrusion.
You. Using the three operation points obtained as described above,
The protrusion size of the protrusion can be easily obtained (for example,
For example, the average value of the Z coordinate of the two calculation points on the left and right and the calculation point in the middle
The difference from the Z coordinate may be used as the protrusion dimension of the protrusion.) (B) The distance between the tip edge of the projection and the displacement sensor 11
Represents the leading edge of the protrusion when the distance is almost constant
This is an example of calculating such calculation points, and calculating the protrusion size of the protrusion.
-(A) -B. Can be replaced with the method of
It is an effective technique. That is, the same intermediate as-(a)
Find two change points and find the point sequence of measurement points between both change points.
And the distance to the displacement sensor 11 is the shortest or more
The distant measurement point is set as the calculation point. (C) between the tip edge of the projection and the displacement sensor 11
When the distance is almost constant, a sudden
This is an example of calculating a calculation point that represents the leading edge of the part,
To obtain the protrusion dimensions of the protrusion,-(a) -B.
This is a method that can be replaced with the method described above. That is,-
In the same way as in (a), find the two intermediate transition points and determine whether each transition point
Difference DZ_iDirection (that is, the left side
If it is a change point, it is already on the right, if it is on the right, it is on the left).
Positions separated by a fixed number (this number can be set arbitrarily)
The measurement point of is used as a calculation point. The operation points can be obtained by the method described above.
For example, when measuring the width of a protrusion, measurement accuracy is improved.
Will be. For example, the width of the protrusion
When measured as distance, it will be larger than the actual size
But-(b) -A. Calculated using the method of
When the width of the protrusion is calculated using points,
Error is reduced. In other words, if you introduce calculation points,
Measurement accuracy and the reproducibility of measured values
You. After determining the operation points using the above-described method,
The arithmetic processing unit 15 calculates the shape of the object surface using the coordinates of the arithmetic point.
Find the dimensions specified for the shape. For example,
Width of the protrusion, etc.
The center position between the two points, the two formed on the object surface
The pitch between holes, the depth of steps, the depth of holes, the height of the center of steps, etc.
The arithmetic processing unit 15 calculates various dimensions that are characteristic dimensions of the object surface, such as
Can be found at Here, the change point is determined by the change point recognition unit 13.
Threshold value at the time of calculation, a method of determining a calculation point by the calculation point recognition unit 14,
The dimensions to be determined by the arithmetic processing unit 15 are determined by parameters.
Selected using the parameters set in the data storage unit 17.
It is. The operation expression used in the operation processing unit 15 is
Initially, multiple items are registered.
Therefore, it was decided which arithmetic expression to use
I have. The object table obtained by the arithmetic processing unit 15 as described above
Various measured values related to surface shape and dimensions are
It is output to the outside through the output unit 16 which is a face. The processing setting section 2 sets the above-described parameters.
Display or display of measured values obtained by the displacement measurement unit 1
Perform In other words, the parameter for entering the parameter
The meter input unit 21 is used to set the operation point by any of the methods described above.
Calculation point setting unit 22 for selecting whether or not
The display unit 23 for displaying measurement information changes the set parameters.
It is transmitted to and stored in the parameter storage unit 17 of the position measurement unit 1,
The parameter set in the parameter storage unit 17 is read.
It has a parameter communication unit 24 that can read out. The parameter input unit 21 has a keyboard and a
The display unit 23 is configured using digital switches.
Fixed points, change points, and calculation points can be displayed as images.
And a CRT and a liquid crystal display. Calculation point setting
The unit 22 includes a change point detection procedure in the change point recognition unit 13,
Calculation point setting method and calculation processing in calculation point recognition unit 14
The same processing as the calculation formula of the measurement dimensions in the part 15 is possible.
The same program is registered as shown
Program according to the parameters input from the force unit 21
Select the same processing procedure as used in the displacement measurement unit 1 from
I can do it. As described above, the displacement measuring unit 1 and the processing setting unit 2
In between, only parameters are exchanged for the procedure.
For this reason, the capacity of the parameter storage unit 17 is reduced.
be able to. In addition, the capacity for storing one process is small.
For example, used to measure the surface shape of one object
Multiple types of processing are collectively recorded in the parameter storage unit 17.
It is possible to remember
It is possible to switch between predetermined procedures only by
You. By using such a method, the shape of the object can be measured.
The accuracy will be higher. Validity of processing procedure for object to be measured
When verifying, while viewing the display on the display unit 23,
Input a settable parameter from the parameter input unit 21
To select a processing method for changing points and calculation points.
Can be. Therefore, a menu format or the like is displayed on the display unit 23.
Display the types of parameters that can be set using
If a parameter is selected in the parameter input unit 21, calculation
In the point setting unit 22, the processing procedure corresponding to the parameter is started.
The measurement point data received through the output unit 16
Change point recognition unit 13, calculation point recognition unit 14,
The same processing as the processing section 15 is performed, and the display section 23
Display the processing result corresponding to the selected parameter immediately
Can choose the best parameters easily
You can. Once the optimal parameters have been selected,
The parameter storage unit 17 through the parameter communication unit 24.
The parameters are stored, and the change point recognition unit 13 and the operation point recognition unit
14, the arithmetic processing unit 15 corresponds to this parameter.
The processing procedure is started. That is, simply select the parameters
Do you need to rewrite the program just by selecting
This makes it easy to set the processing procedure. Moreover, the parameters
Is stored in the parameter storage unit 17,
After setting, the process setting unit 2 is separated from the displacement measuring unit 1.
Alternatively, they can be used alone. In this case, the displacement meter
The output result from the output unit 16 is displayed on the measuring unit 1 as a numerical value.
Display, measurement points, change points, and calculation points as images
Connected only to the displacement measurement unit 1
Good. Further, the parameter storage unit 17 described above
Data is exchanged bidirectionally with the parameter communication unit 24.
Since it can be received, it is stored in the parameter storage unit 17.
The read parameters are read from the processing setting unit 2 and displayed on the display unit.
23 for easy confirmation of processing procedures
be able to. This allows for
What can be done easily. The processing of the calculation point setting unit 22 will be briefly described.
First, the shape of the object surface transmitted from the displacement measurement unit 1
Parameter input unit 2 based on the data of the measurement points
Change point is determined by the processing procedure corresponding to the parameter selected in 1.
Detect and set parameters corresponding to the calculation points in the same way,
Display the calculation point corresponding to the parameter
23. In this way all desired operations
After setting points, output the shape and dimensions of the desired location
Set the parameters corresponding to the information to be
The calculation corresponding to the data is performed and displayed on the display unit 23.
In this way, when all settings are completed,
Parameters to the parameter storage unit 16 through the data communication unit 24.
Transfer the data and disconnect the process setting unit 2 from the displacement measuring unit 1.
You. In the configuration described above, the measurement data correction unit 12
The other configuration except for the above is described in Japanese Patent Application No. 6-77713 filed earlier.
It is the same as that described in the item. (Example 1)Basic configuration Is the displacement of the object surface as shown in FIG.
FIG. 4 shows an example in which 変 化 changes relatively slowly.
As shown in (a), a steep rise in displacement of the object surface
When there isBasic configurationApplying the method of FIG.
As shown in (e), the measured value can be sufficiently corrected.
It may not be possible. An object with a shape as shown in FIG.
Changes the correction method in the measurement data correction unit 12
4 (b), the received light amount exceeds the threshold value Tu and becomes excessively large.
4, the measured value of the displacement sensor 11 is
As shown in (c), the measurement data correction unit 12
It is not only the displacement in the Z direction immediately before the light amount exceeds the threshold value Tu.
By substituting the scanning position in the X direction for FIG.
A measurement result that is relatively close to the surface shape of the object as shown in (d)
Obtainable. In short, the received light amount exceeds the threshold value Tu.
Do not use the values measured by the displacement sensor 11 in a certain range.
Only the measured value in the range where the amount of received light is equal to or less than the threshold Tu is used.
It is. The method of this embodiment is used when the amount of received light is too small.
Can also be used. In other words, a lower threshold is set.
If the amount of received light is below the lower threshold,
The value measured by the displacement sensor 11 is not used. other
Configuration and operationBasic configurationIs the same as (Reference example)This example Now, the measurement data when the amount of received light is too small
An example of another correction method in the correction unit 12 will be described. Now, the floodlight
Between the scanning range of the camera and the upper and lower limits of the amount of received light
And the displacement measurement range is the range as shown by the hatched portion in FIG.
Shall be restricted to At this time, in FIG.
Part having a distance beyond the measurement range on the surface of the object
Position is present (for example, a deep hole is formed
Case), the reflected light for the projected beam is
It is hardly obtained and the amount of received light is too small. Such a shape
When the displacement is obtained for the object of FIG.
The result of measurement by the displacement sensor 11 is shown in FIG.
become that way. here,Basic configurationLight intensity is too low
By substituting the value just before
This results in a measurement result as shown in FIG.
You. This does not match the shape of the actual object surface
is there. Therefore,This exampleThen, the shape as shown in FIG.
Received light is too small when measuring objects of different sizes
Assuming that the farthest measurable displacement has been obtained.
Substitute that value. That is, as shown in FIG.
In addition, in places where the amount of received light is too small, the displacement must be large.
Can be shown. Other configurations and operations areBasic configurationWhen
The same is true. (Example 2) In this embodiment,The configuration of the reference example is combined with the configuration of the first embodiment.
LetThe measurement data correction unit 12
This is a preferred embodiment. That is, as shown in FIG.
Regarding the amount of light received by the displacement sensor 11, the upper limit threshold and the lower limit
A threshold value is set (S1), and the amount of received light is within the range of both threshold values.
If it is within (S2), the measurement value of the displacement sensor 11 changes
This is given to the point recognition unit 13. On the other hand, the amount of received light exceeds the upper threshold
(S3),Example 1Adopt methodAnd
StrangeThe received light amount exceeds the threshold for both the position and the scanning position.
Is used (S4). Also, the amount of received light
Is less than the lower threshold (S5),Example 1
Any of the examplesAdopt methodAnd strangePosition and scanning position
Use the value just before the received light amount falls below the threshold for both
Or use the farthest measurable value as the measured value
That is (S6). Due to the above processing, the amount of received light is excessive.
It is possible to obtain a relatively good measurement result even if it is too large or too small.
Wear. Other configurations and operations areBasic configuration, Example 1, Reference
An exampleIt is based on. [0039] 【The invention's effect】The present inventionThe amount of light received by the light receiving
When out of rangeToImmediately after the light intensity crosses the specified threshold
Suppress extreme fluctuations in measurement results by substituting the previous displacement
To obtain a measurement result that is relatively close to the shape change of the object.
There is an advantage that you can. [0040]The displacementNot just the scanning position
Therefore, the shape is changed so that the amount of received light becomes too large or too small.
Measurement will not be performed in the part where
When it is possible to obtain measurement results for only the measurable part
There are advantages.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a basic configuration . FIG. 2 is an operation explanatory diagram in the case where the amount of received light in the basic configuration is excessive. FIG. 3 is an operation explanatory diagram in a case where the amount of received light in the basic configuration is too small. FIG. 4 is an operation explanatory diagram in the case where the amount of received light is excessive in the first embodiment . FIG. 5 is an operation explanatory diagram in a case where the amount of received light is too small in the reference example . FIG. 6 is an operation explanatory diagram according to the second embodiment . FIG. 7 is a schematic configuration diagram of a displacement sensor. FIG. 8 is a diagram illustrating a measurement principle of a displacement sensor. [Description of Signs] 11 Displacement sensor 12 Measurement data correction unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-88726 (JP, A) JP-A-4-364411 (JP, A) JP-A-6-213631 (JP, A) 143306 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00-21/30 G01B 5/00-5/30 G01C 3/06

Claims (1)

(57) [Claims 1] Light emitting means for scanning a light beam on the surface of an object so that the light emitting spot moves on the surface of the object and projecting the light, and receiving an image of the light emitting spot A light receiving means for forming an image on a light receiving surface of a light receiving element through an optical system and outputting a position signal including information on a light receiving amount and a position of an image forming spot; An optical displacement measuring apparatus comprising: an arithmetic means for obtaining a measurement result associated with a scanning position of a light beam; when the amount of light received by the light receiving means is out of a specified range,
Measure the scanning position and displacement of the light beam previously determined
Optical displacement measuring equipment, characterized by comprising providing a measurement data correcting section that substitute as 査position and displacement.