JPH0961120A - Dimension measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dimension measuring instrument for accurately measuring a dimension by measuring the inclination angle around a horizontal axis and performing correction processing. SOLUTION: When reflection light from a surface 20B to be measured is received by a two-dimensional CCD sensor 34 and a digital signal indicating the trace of a bright point on the surface 20B to be measured is received by an operation device 38, the operation device 38 calculates a depth dimension formed on the surface 20B to be measured based on the digital signal. Further, an inclination angle around the horizontal axis is measured by an angle measuring mechanism 58 and it is used along with the calculated depth dimension to perform correction processing, thus measuring the dimension of a desired part and displaying it on a liquid crystal display 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a size measuring instrument for measuring the size of a desired portion of a measured object by irradiating the measured surface of the measured object with slit light and receiving the reflected light.

[0002]

2. Description of the Related Art Conventionally, when measuring a dimension of a desired portion with respect to an object to be measured, a slit-shaped light beam (hereinafter referred to as a slit-shaped light beam from a light source provided in a measuring device toward a surface to be measured)
This is referred to as slit light) is irradiated at a predetermined angle, and a line (hereinafter referred to as a light cutting line) reflected on the surface to be measured of the irradiated slit light is photographed using a TV camera, and the video output from this is taken. By performing arithmetic processing based on the signal, the coordinates of each point on the surface of the three-dimensional object to be measured along the light cutting line are measured. Also, by using the triangulation device that receives the reflected light of the irradiated slit light and obtains the light receiving position (horizontal light cutting position, vertical light cutting position),
A measuring device (see Japanese Patent Laid-Open No. 64-78109) capable of measuring the three-dimensional coordinate value of a reflected point on the surface to be measured has been proposed.

However, in the above measuring apparatus, a measurement error occurs when the relative position between the object to be measured and the measuring head (TV camera) irradiated with slit light changes each time the measurement is performed. For example, when the measurement head is held by an operator, the posture of the measurement head changes every measurement, the relative position changes, and a measurement error occurs.

In this regard, the applicant of the present invention has proposed a device having an indicator for instructing that the luminous flux surface of the slit light should be substantially perpendicular to the object to be measured at the time of measurement (Japanese Patent Application No. 6-260674). However, in this case, there is a problem in that the adjustment of the measuring instrument is complicated and the measurement work takes time. When the operator sets the measuring head on the object to be measured while holding it by hand, the vertical axis, that is, the left and right directions can be opposed to each other with relative accuracy, but the horizontal axis direction, that is, the vertical direction is the same. It is experimentally known that the displacement amount is large.

[0005]

SUMMARY OF THE INVENTION In consideration of the above facts, the present invention automatically detects at least a tilt around a horizontal axis which tends to tilt in a hand-held state, and corrects a dimension measurement value to measure a surface to be measured. It is an object of the present invention to provide a size measuring instrument capable of accurately obtaining the size of the.

[0006]

According to a first aspect of the present invention, there is provided an emitting means for emitting slit light, and a locus of a bright spot on the object to be measured which receives the reflected light of the slit light and reflects the slit light. On the measured object output from the signal output means, an angle measuring means for automatically detecting an inclination around at least a horizontal axis when facing the measured object, And a calculating means for calculating a dimension of a desired part of the object to be measured corresponding to each line segment forming the locus of the bright spot, based on the signal representing the locus of the bright spot and the angle measured by the angle measuring means. And output means for outputting the calculation result by the calculation means, and irradiating the measured surface of the object to be measured with slit light in a state of gripping the casing in which these are stored, and measuring the size of the desired part. It is characterized by measuring.

According to the first aspect of the present invention, when the operator holds the casing so that the slit light emitted by the emitting means is irradiated on the object to be measured, the signal output means outputs the reflected light of the slit light. It receives the light and outputs a signal representing the locus of the bright spot on the object to be measured that reflects the slit light.
Further, since the angle measuring means is provided, it is possible to measure at least the angle about the horizontal axis even when the measuring device is tilted with respect to the object to be measured. In addition,
The tilt about the vertical axis can be ignored as it is within the tolerance range.
Then, based on the signal representing the locus of the bright spot on the DUT output from the signal output means in the computing means and the angle obtained by the angle measuring means, the size of each line segment forming the locus of the bright spot Can be calculated to measure the dimensions of the desired part.

The invention described in claim 2 is characterized in that, in the invention described in claim 1, the angle measuring means detects an inclination about a vertical axis in addition to a measurement of an inclination angle about a horizontal axis. .

According to the second aspect of the present invention, in addition to measuring the tilt angle about the horizontal axis when measuring the dimension of a desired portion of the object to be measured while holding the dimension measuring instrument by hand, Since the tilt angle around the vertical axis is measured, the measurement accuracy of the dimension measuring device can be improved. However, it cannot be denied that the processing time becomes longer than that of the dimension measuring device according to the first aspect.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A dimension measuring instrument 10 according to an embodiment of the present invention will be described below.

In the following embodiments of the invention, an object to be measured 20 having a rectangular groove portion 20A with a constant depth formed on the side surface as shown in FIG. Of the depth dimension L and the width dimension Q existing in the groove portion 20A in the measured object 20, the depth dimension L will be described as an example.

Further, in the dimension measuring instrument 10 of the present invention, it is premised that the operator holds the dimension measuring instrument 10 facing the object to be measured 20 and that there is no inclination around the vertical axis of the dimension measuring instrument 10, that is, right and left. It is designed to measure as. Regarding the inclination of the dimension measuring device 10 about the vertical axis, it is possible to almost accurately make the inclination close to zero even if there is no means to judge it. Since a considerable error may occur, the dimension measuring device 10 of the present invention rotates around the horizontal axis (rotation axis 1-1 line in FIG. 1).
Measure the tilt angle of.

FIG. 1 shows a dimension measuring device 10 according to an embodiment of the present invention. The dimension measuring device 10 is covered with a casing 12 that is a substantially rectangular parallelepiped, and the casing 12 takes an image of a projection device 22 that emits the slit light 14 and an irradiation position of the slit light 14 that irradiates the measured surface 20B. The light receiving device 30 is provided on the same surface. Further, with respect to the measured surface 20B of the measured object 20,
Considering that the slit light 14 may not be emitted vertically, an angle measuring mechanism 58 for measuring the inclination angle of the dimension measuring device 10 about the horizontal axis is provided in the casing 12. A liquid crystal display 18 is provided on the surface of the dimension measuring device 10 opposite to the slit light 14 output / input surface so that numerical values such as measurement results are displayed.

FIG. 2 shows a state in which the dimension measuring device 10 is set at an inclination angle with respect to the object 20 to be measured. 2A shows a state in which the object to be measured 20 and the dimension measuring device 10 are viewed from the direction of the arrow 2A shown in FIG. 1, that is, from above, and FIG. 2B similarly shows the arrow 2B in FIG.
The side view which looked at to-be-measured object 20 and dimension measuring device 10 from the direction of is shown. 2B is the inclination angle of the dimension measuring device 10.

The detailed structure of the dimension measuring instrument 10 according to the embodiment of the present invention will be described below with reference to FIG.

The light projecting device 22 includes a semiconductor laser 24 as a light source necessary for irradiating the slit light 14, a collimator lens 26 composed of a spherical lens for converging the beam, and the converged beam in one direction. It has a rod lens 28 for diverging to. In addition, the light receiving device 3
0 is provided with a light receiving lens 32 and a two-dimensional CCD sensor 34. Further, the arithmetic unit 38 is connected with a switch 40 for instructing start or stop when performing measurement using the dimension measuring device 10 according to the embodiment of the present invention.

According to the dimension measuring device 10, the light projecting device 2
When the slit light 14 emitted from the rod lens 28 provided inside 2 is applied to the measured surface 20B of the measured object 20, the locus 16 of bright points (hereinafter, Bright line) occurs. The slit light 14 applied to the measured surface 20B passes through the light receiving lens 32 and is imaged on the light receiving surface of the two-dimensional CCD sensor 34. From this, on the light receiving surface of the two-dimensional CCD sensor 32, an image 36 of the bright line on the measured surface 20B (hereinafter referred to as a slit image).
Will be imaged. In addition, the two-dimensional CCD sensor 3
4 outputs an electric signal according to the position of the slit image 36 and the light intensity to the arithmetic unit 38 for subsequent processing.

As shown in FIG. 4C, the device under test 2
When the slit light 14 emitted from the light projecting portion 22 is vertically irradiated onto the measured surface 20B of 0, the slit image has the same size as the originally desired depth size as shown in FIG. 36 can be obtained. However, as shown in FIG. 4 (A) or FIG. 4 (E), the operator holds the dimension measuring instrument 10 in an inclined state with respect to the measured surface 20B of the measured object 20, and the slit light 14 is When the surface to be measured 20B is obliquely irradiated, the surface shown in FIG.
As shown in (F), the depth dimension of the slit image 36 formed on the light receiving surface is longer than the original depth dimension, and the slit image 36 is imaged on the light receiving surface.

Therefore, in consideration of the case where the slit light 14 is inclined and emitted from the dimension measuring instrument 10 as described above, it is necessary to measure the inclination angle between the dimension measuring instrument 10 and the object 20 to be measured. There is. Therefore, the angle measuring mechanism 58
Is provided, and a correction process is performed using the angle thus obtained to obtain the dimension of a desired portion (depth dimension L in the embodiment of the present invention). The angle measuring mechanism 58 will be described later.

The arithmetic unit 38 includes an amplifier circuit (AMP) 4
2. An analog-digital converter 44 (hereinafter referred to as an A / D converter) and a microcomputer 46 (microcomputer) are provided. The input end of the amplifier circuit 42 is connected to the two-dimensional CCD sensor 34, and a signal output from this is amplified by a predetermined amplification factor and output. Since the output end of the amplifier circuit 42 is connected to the input end of the A / D converter 44, the data output from the amplifier circuit 42 is
It will be input to the converter 44. Further, the output terminal of the A / D converter 44 is connected to the microcomputer 46,
Here, calculations for measurement and error correction are performed. The microcomputer includes a CPU 50, a ROM 52, a RAM 54, and an input / output port 48 for inputting / outputting with an external device, all of which are connected by a bus 56,
Data and commands can be exchanged with each other. Further, the input / output port 48 is also connected to a switch 40 for starting or stopping the emission of the slit light 14, an angle measuring mechanism 58 for measuring the tilt angle, and the liquid crystal display 18.

A rotary encoder is used as the angle measuring mechanism 58 in the embodiment of the present invention (see FIG. 8).

As shown in FIG. 8, a weight 68 is attached to the disk slit 62 of the rotary encoder in the vertical direction (gravitational direction). The weight 68 has a function of rotating the disk slit 62 relative to other members when the dimension measuring device 10 is inclined with respect to the horizontal axis, and always positioning the disk slit 62 immediately below. Therefore, the motor 6
The pulse generated by rotating the disk slit 62 is detected by 0, and the pulse is counted, and the sensor 70 detects the slit 64 directly below the weight 68. The motor 6 that was being driven after the detection was completed
By stopping 0, the tilt angle θ can be obtained from the count number and the unit pulse angle.

As an operation of the dimension measuring device 10 according to the embodiment of the present invention, a case of measuring the depth L of the groove 20A formed in the object 20B will be described below.

As shown in FIG. 1, the surface of the casing 12 of the dimension measuring device 10 on which the light projecting device 22 and the light receiving device 30 are present is directed toward the surface 20B to be measured of the object 20 to be measured. It is held by the operator. Further, it is assumed that the inclination of the dimension measuring device 10 about the vertical axis is substantially equal to zero. This is because the inclination around the vertical axis can be set to a state close to zero by the manual operation of the operator.

When the measurement of a predetermined portion is started, the switch 40 provided in the dimension measuring device 10 is turned on. When the switch 40 is turned on, the slit light 14 is emitted from the light projecting device 22, which is a light source, and irradiates the measured surface 20B of the measured object 20. As a result, the measured surface 2
The bright line 16 appears on 0B. Measured surface 20
The slit light 14 reflected by B passes through the light-receiving lens 32 and is applied to the light-receiving surface of the two-dimensional CCD sensor 34 and the measured surface 2
An image (slit image 36) of the bright line 16 that changes according to the unevenness on 0B is formed. Two-dimensional CCD sensor 3
4 outputs an electric signal according to the position of this slit image 36 and the light intensity to the arithmetic unit 38.

The slit image 36 input to the arithmetic unit 38
The electric signal of 1 is first amplified by the amplification circuit 42 at a predetermined amplification factor and input to the A / D converter 44. Subsequently, the A / D converter 44 samples the signal at predetermined time intervals, converts it into a digital signal, and outputs the digital signal to the microcomputer 46.

When a digital signal is input to the microcomputer 46, the CPU 50 is supposed to detect it, and upon completion of this detection, a control routine by the CPU 50 as shown in FIG. 6 is started.

The flow of this control routine will be described below. First, in step 100, an electric signal (detection signal) corresponding to the position and light intensity of the slit image 36 output by the two-dimensional CCD sensor 34 is amplified in the arithmetic unit 38, and a signal obtained by analog-digital conversion is fetched.

Subsequently, in step 102, a calculation for measuring the depth dimension is performed based on the slit image 36. This will be described in detail below.

The slit image 36 formed on the light receiving surface of the two-dimensional CCD sensor 34 corresponds to the concave portion formed in the central portion of the surface 20B to be measured as shown in FIG. Only the central portion along the line is an image displaced in the negative direction of the Z axis. Further, it is known that the amount of displacement of the Z axis in the negative direction has a correlation with the size of the depth dimension of the recess.

On the other hand, the output signals of the arbitrary scanning lines 37A and 37B corresponding to the Z-axis direction of the light receiving surface are shown in FIG.
It becomes as shown in (C). Two-dimensional CCD sensor 34
Outputs such a signal to the arithmetic unit 38. The part where the amplitude of this output signal is large is the slit part on the scanning line,
That is, it becomes the position of the slit image 36.

Therefore, the positions of the slit images 36 on all scanning lines on the light receiving surface are calculated by the arithmetic unit 38 based on the input signals, and the slit images 36 are calculated from the calculated positions.
The depth dimension of the surface to be measured 20B can be obtained based on the correlation between the amount of displacement of the Z axis in the negative direction and the depth dimension of the recess. The depth dimension measured here is assumed to be M.

Then, in step 104, the angle measuring mechanism 58 provided in the casing 12 measures the inclination angle of the dimension measuring instrument 10 with respect to the horizontal direction. As described above, only the angle around the horizontal axis is measured, and the inclination angle around the vertical axis can be brought close to zero because it can be easily performed manually by the operator. In order to measure this tilt angle, the measurement routine shown in FIG. 7 is executed.

First, in step 200, the count number N is initialized to zero. Continue to step 202
In step 1, the motor 60 provided in the angle measuring mechanism 58 is driven, and in step 204, the pulse generated by the rotation of the disc slit 62 is detected. If a pulse is detected here, step 206
And the count number N is incremented by one. Further, in step 208, the sensor 70 detects the slit 64 immediately below the weight 68. Here, the sensor 70 performs the slit 64 process in steps 204 and 206.
Is executed until is detected. When this detection is completed, the drive of the motor is stopped in step 210, and in step 212, the tilt angle θ to be obtained from the count number N and the unit pulse angle obtained by the above processing is to be obtained.

It is considered that the inclination angle θ falls within the range of −90 ° to 90 ° when the horizontal axis is 0 °.
If it is out of this range, the slit light 14 is emitted from the object 2 to be measured.
Since the measured surface 20B of 0 is not irradiated at all, it is excluded.

When the execution of the measurement routine as described above is completed, the process returns to step 106 of the control routine, and the angle θ measured in step 104, that is, the measurement routine, and the depth dimension measured in step 102 are used for the measurement. The optimum depth dimension is obtained by substituting into the formula shown in.

L = M × cos θ (1) L: Depth dimension to be obtained M: Measured value of depth dimension θ: Inclination angle of the dimension measuring instrument where the inclination angle of the dimension measuring instrument 10 is zero, That is, when the inclination is not present, the value measured in step 102 of the control routine can be obtained as the dimension of the depth dimension L to be originally obtained without performing the correction process. In this case, the measurement routine is performed. In this case, the inclination angle θ is measured as zero, and this zero is substituted into the above equation to perform the correction process. Even if zero is substituted, the same result as the value measured in step 102 is obtained. Therefore, the control routine and the measurement routine are executed regardless of whether or not the dimension measuring instrument 10 is tilted.

By performing a correction process using the above equation, an accurate measured value of the depth dimension L to be obtained can be obtained. Then, the switch 40 provided in the dimension measuring instrument 10 is turned off. Then, the execution of the control routine is stopped, and at the same time, the emission of the laser beam from the semiconductor laser 24 in the light projecting device 22 is also stopped. The calculation result obtained by measuring the desired portion (the depth dimension L in the embodiment of the present invention) by the above processing is displayed on the liquid crystal display 18 which is an output means, and the dimension measurement processing of the desired portion is completed. Become.

The tilt angle of the dimension measuring device 10 about the vertical axis can be adjusted to almost zero by the manual operation of the operator. However, in order to obtain a more accurate dimension measuring device, the tilt angle about the horizontal axis can be adjusted. Angle measuring mechanism 58 for measuring
In addition to the above, a tilt adjustment instruction section 19 for adjusting the tilt around the vertical axis (the rotation axis 2-2 line in FIG. 9) may be provided.

As shown in FIG. 9, this is provided on the surface opposite to the surface on which the light projecting device 22 and the light receiving device 30 are provided, that is, on the same surface where the liquid crystal display 18 is installed. There is. The tilt adjustment instructing section 19 includes a right lamp 19A for instructing to adjust the attitude of the casing 12 to the right, a central lamp 19B for instructing to maintain the attitude of the casing 12 as it is, and a casing 12.
Left lamp 19 that instructs you to adjust your posture to the left
C is provided.

Therefore, in order to eliminate the inclination around the vertical axis, the central lamp 19B of the inclination adjustment instructing section 19 may be adjusted to be turned on. This adjustment work is performed immediately after the switch 40 for instructing the start of measurement is turned on, and the above-described processing is subsequently performed. This makes it possible to correct the tilt angles around both the vertical and horizontal axes, so that more accurate dimension measurement can be performed.

As described above, the dimension measuring device 10 according to the embodiment of the present invention needs to determine whether the luminous flux surface of the slit light 14 is perpendicular to the measured object 20B of the measured object 10. However, the inclination angle θ around the horizontal axis of the dimension measuring device 10 can be obtained regardless of whether it is vertical or not, and correction processing can be performed using this, so that the problems that have conventionally occurred can be solved. , Can measure accurate dimensions. However, this is the case where the DUT 20 is placed perpendicular to the plane and only the dimension measuring device 10 is tilted, and both the DUT 20 and the dimension measuring device 10 are tilted with respect to each other. In this case, the data of the inclination angle with respect to the direction of the center of gravity (around the horizontal axis) of the DUT 20 is previously stored in the microcomputer
You need to register with.

In the embodiment of the present invention, an example of measuring the depth dimension of the surface to be measured is shown, but the dimension measuring instrument 10 of the present invention measures the dimension of other local parts. You can also

In the embodiment of the present invention, the example in which the slit-shaped light is obtained by using the rod lens has been described, but a cylindrical lens, a cylindrical mirror or the like can be used as an element for obtaining the slit-shaped light.
It is also possible to obtain slit-shaped light by scanning a laser beam from a rotating polygon mirror or the like.

Further, although the case where the two-dimensional CCD sensor is used as the light receiving element has been described in the embodiment of the present invention, the invention is not limited to the two-dimensional CCD sensor.
An element capable of outputting a two-dimensional position on the sensor using a position detection method by a television system using a three-dimensional CCD sensor or an image pickup tube may be used.

Further, in the embodiment of the present invention,
As the angle measuring means, the method of measuring the angle by attaching a weight to the rotary encoder has been described as an example. However, instead of using the rotary encoder, there is a method of using an optical fiber type gyro sensor instead. With this optical fiber type gyro sensor, for example, in the case of a phase modulation method, an output that is a SIN function is obtained when the angular velocity is ω. As a result, the sensitivity when the angular velocity ω is near zero is improved, and the rotation direction can be obtained. By using this as the angle measuring mechanism in the dimension measuring instrument 10 of the present invention, the angle required for measurement is obtained. It is also possible. It is also conceivable to provide a dial on the surface opposite to the surface of the dimension measuring instrument on which the light projecting device for emitting the slit light is provided, and the operator rotates the dial to measure the angle.

In the embodiment of the present invention, a liquid crystal display is used as the depth dimension output means. However, the depth dimension output means is not limited to the liquid crystal display. A method of outputting the measured value by printing on a storage medium such as paper, a method of outputting the measured value by voice using an audio output device such as a speaker, and the like are also possible.

[0048]

As described above, the dimension measuring instrument according to the present invention solves the problem that the dimension of a desired portion cannot be accurately measured due to the shaking of the operator who holds the dimension measuring instrument. When measuring, it is not necessary for the operator to perform complicated adjustment work for making the luminous flux surface of the slit light beam perpendicular to the object to be measured, and even when the dimension measuring instrument is arranged at an inclination, By performing a correction process using the inclination angle, it is possible to obtain an accurate measurement value of a desired portion.

Further, in addition to the measurement of the inclination angle about the horizontal axis, the dimension can be measured with higher accuracy by adjusting so as to eliminate the inclination about the vertical axis.

[Brief description of drawings]

FIG. 1 is a perspective view showing the external appearance of a dimension measuring instrument according to an embodiment of the present invention.

2A is a side view of the object to be measured and the dimension measuring instrument viewed from the direction of arrow 2A in FIG. 1, and FIG. 2B is a view from the direction of arrow 2B in FIG.

FIG. 3 is a block diagram showing a schematic configuration of a dimension measuring device according to an embodiment of the present invention.

4A and 4E show a state in which the slit light is inclined with respect to the measured surface of the measured object, and FIG. 4C is a state in which the slit light is perpendicular to the measured surface of the measured object. It is a schematic diagram which shows a certain state, (B), (D), and (F) show the irradiation state of the reflected light in the light-receiving surface of the two-dimensional CCD sensor in the case of (A), (C), and (E), respectively. It is a diagram showing.

5A is a diagram showing a state when a laser beam is irradiated on the light receiving surface of the two-dimensional CCD sensor, and FIGS. 5B and 5C are diagrams showing output signals from the two-dimensional CCD sensor.

FIG. 6 is a flowchart showing a control routine by a microcomputer.

FIG. 7 is a flowchart showing a measurement routine by the angle measurement mechanism.

FIG. 8 is a side view when a rotary encoder with a weight is used as an example of an angle measuring mechanism.

FIG. 9 is a perspective view showing the external appearance of a dimension measuring instrument provided with an indicator as a tilt adjustment instruction section.

[Brief description of reference numerals]

 10 Dimension Measuring Device 12 Casing 14 Slit Light 16 Locus of Bright Spots (Bright Lines) 18 Liquid Crystal Display (Output Means) 19 Inclination Adjustment Instructing Section (Indicating Means) 20 Object to be Measured 22 Light Emitting Section (Emitting Means) (Emitting Means) 30 light receiving part (light receiving device) 34 two-dimensional CCD sensor (signal output means) 36 slit image 38 arithmetic unit 40 switch 46 microcomputer 58 angle measuring mechanism (angle measuring means) 60 motor 62 disc slit 64 slit 68 weight 70 sensor

Claims (2)

[Claims] 1. An emission means for emitting slit light, a signal output means for receiving the reflected light of the slit light and outputting a signal representing the locus of a bright spot on the object to be measured which reflects the slit light, and the measured object. An angle measuring unit that automatically detects at least a tilt around a horizontal axis when facing an object, a signal output from the signal output unit and representing the locus of bright spots on the measured object, and the angle measuring unit. Based on the measured angle, a calculating means for calculating the size of a desired portion of the measured object corresponding to each line segment forming the locus of the bright spot, and an output means for outputting the calculation result by the calculating means. A dimension measuring instrument for measuring the dimension of a desired portion by irradiating the surface to be measured of the object to be measured with slit light while holding the casing in which these are held. 2. The dimension measuring device according to claim 1, wherein the angle measuring means detects an inclination about a vertical axis in addition to the measurement of an inclination angle about a horizontal axis.