JPH1123231A - Non-contacting thickness measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contacting thickness measuring instrument which can measure the thickness of an object to be measured with high accuracy by relieving the restriction on the shape of measurable objects. SOLUTION: A thickness measuring instrument is provided with an optical measuring head 10 equipped with optical measuring sensors 11a and 11b which output beams of light and signals having magnitudes proportional to the lengths of the beams of light to an object to be measured 40 from the displacement of the reflected light rays of beams of light and has an inserting port 13 for inserting the object 40 and an arithmetic and display device which finds the thickness of the object 40 by individually fetching the output signals of the sensors 11a and 11b through a cable 30 and converting the data into digital data and displays the found thickness. In the inserting port 13 of the head 10, in addition, the beams of light outputted from the sensors 11a and 11b respectively advance in the opposite directions on the same optical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact thickness measuring device for measuring the thickness of an object to be measured using a light beam,
The present invention relates to a non-contact thickness measurement device suitable for performing high-accuracy measurement using a plurality of optical measurement sensors.

[0002]

2. Description of the Related Art As an apparatus for measuring the thickness of an object to be measured in a non-contact manner with high accuracy, there is an apparatus using one optical measurement unit. This type of measuring device includes a base for installing an object to be measured, and an optical measurement unit fixed to the base at a fixed interval, and a distance between the base measured by the optical measurement unit and The difference in the distance from the object to be measured is defined as the thickness of the object to be measured.

[0003]

However, in the above-described conventional measuring apparatus, measurement can be performed only when the object to be measured has a planar shape that can be installed close to the base. For example, as shown in FIG. 7, when the object to be measured has irregularities and the part to be measured cannot be installed on the base, or when the part to be measured is installed on the base, the light beam of the optical measurement unit is If it is obstructed by another part, no measurement can be made.

Accordingly, an object of the present invention is to provide a non-contact thickness measuring apparatus capable of relaxing the restriction on the shape of the object to be measured and performing highly accurate measurement.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method of outputting a light beam, and obtaining a signal having a magnitude proportional to the length of the light beam from the displacement of the reflected light of the light beam to an object to be measured. The optical measurement head having two optical measurement sensors that output the data, the optical measurement head in which the insertion port into which the object to be measured is inserted is formed, and the signals output from the two optical measurement sensors are individually captured via a cable, A / which converts to digital data in parallel
D conversion unit, display unit, and, based on digital data converted from signals output from the two optical measurement sensors at the same time, calculate thickness data representing the thickness of the measured object,
A non-contact thickness measurement device, comprising: a calculation display device including a calculation processing unit for displaying on the display unit.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a non-contact thickness measuring device according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a non-contact thickness measuring apparatus according to this embodiment. As shown in the figure, the non-contact thickness measuring device performs an operation based on an optical measurement head 10 for measuring the thickness of an object to be measured, a cable 20 for transmitting a measurement result and a power supply, and a measurement result. A calculation display device 30 for displaying an accurate thickness of the measured object.

The optical measuring head 10 has two optical measuring sensors 11a and 11b. As shown in FIG. 2, each of the optical measurement sensors 11a and 11b includes a semiconductor laser 111 for generating laser light, a light receiving element group 112 for detecting displacement of reflected light from the device under test 40, and a light receiving element group 112. The drive conversion circuit 113 outputs a current having a magnitude proportional to the distance to the device under test 40 according to the detection result.

FIG. 3 is a sectional view of the optical measuring head 10. As shown in the figure, beside the insertion port 13 of the optical measurement head 10, corresponding to the optical measurement sensors 11a and 11b,
Two reflecting mirrors 12a and 12b, which are members for changing the directions of the light beam and the reflected light, are arranged.

The optical measurement sensors 11a and 11b are arranged at a certain interval, and output laser beams Ba and Bb of an optical axis parallel to the direction of insertion of the object to be measured as shown by arrows. The two reflecting mirrors 12a and 12b
The output laser beams Ba and Bb are refracted toward the insertion port 13 side. Here, the arrangement positions and angles of the reflection mirrors 12a and 12b are determined so that the two laser beams Ba and Bb in the insertion port 13 travel in the opposite directions on the same optical axis.

When the object 40 is inserted into the insertion opening 13 of the optical measurement head 10, the laser beam Ba output from the semiconductor laser 111 of the optical measurement sensor 11a is reflected by the reflection mirror 12a, and Irradiated at 40. As a result, the laser light reflected by the device under test 40 is reflected by the reflection mirror 12a, and the light receiving element group 1 of the optical measurement sensor 11a
12 is detected. Then, a current having a magnitude proportional to the length La of the optical axis of the laser beam Ba (see FIG. 2) is output from the optical measurement unit 12a. Similarly, the laser beam B output from the semiconductor laser 111 of the optical measurement sensor 11b
b is reflected by the reflection mirror 12b and irradiates the device under test 40. Then, the reflected light is reflected by the reflection mirror 12b and detected by the light receiving element group 112 of the optical measurement sensor 11b. Then, the current Ib having a magnitude proportional to the length Lb of the optical axis of the laser beam Bb is output from the optical measurement unit 12b.
Is output.

As shown in FIG. 1, the arithmetic and display unit 30 comprises:
An AD conversion unit 31, an arithmetic processing unit 32, a memory 33,
It has a display unit 34 and a data output terminal 35.

As shown in FIG. 4, the A / D converter 31
An I / V conversion circuit 311 for converting a current into a voltage, and an A / V converter for converting the converted voltage into digital data at fixed time intervals
It has two blocks each including a / D conversion circuit 312 and a register 313 for holding the converted digital data. One block takes in the output current Ia of the optical measurement sensor 11a and outputs distance data Da having a value according to the magnitude of the current Ia. The other block captures the output current Ib of the optical measurement sensor 11b and outputs distance data Db having a value according to the magnitude of the current Ib. The distance data Da and Db output at this time are based on the currents Ia and Ib output from the optical measurement head 10 at the same time.

The arithmetic processing unit 32 has a processor, a ROM storing a processing program for the processor, and an interface circuit for inputting and outputting data (not shown). The processor calculates the accurate thickness of the device under test 40 by executing the processing program and causes the display unit 34 to display it. At this time, the processor stores the calculation data in the memory 33 and determines the final thickness using the calculation data. In parallel with this, data to be operated by the processor and data of the operation result are output to the data output terminal 35. The ROM further stores a characteristic function for correcting the value of the distance data and the optical measurement sensor 11.
The length X of the optical axis of the laser beam between a and 11b and the number of repetitions N are stored.

FIG. 5 is a flowchart showing the processing contents of the arithmetic processing unit 32.

After the power is turned on, the arithmetic processing section 32 first substitutes 1 for a variable m (step 51). And A / D
The distance data Da and Db are read from the register 313 of the conversion unit 31 (step 52), and the distance data Da and Db are corrected using the characteristic function stored in the ROM (step 53). Thereby, the length La of the optical axis of the laser beam output from the optical measurement sensor 11a to the object 40 and the length Lb of the optical axis of the laser beam output from the optical measurement sensor 11b to the object 40 are calculated. (Fig. 2
reference). Next, the arithmetic processing unit 32 includes the optical measurement sensor 11a
The length Lx of the device under test 40 is calculated by reading the length X of the optical axis of the laser beam between the steps 11 and 11b from the ROM and subtracting the sum of La and Lb from L (step 54).
Then, the calculated thickness Lx is stored in the memory 33 (step 55), and it is determined whether or not the variable m is equal to the number of repetitions N of the ROM (step 56). If they are not equal, 1 is added to the variable m (step 57), and the process returns to step 52. If the variable m is equal to the number of repetitions N, the N thicknesses Lx stored in the memory 33
Is read out, and the minimum value Lx is displayed on the display unit 34 (step 58).

The optical measuring head 10 and the arithmetic and display unit 3
A button may be provided at 0 to accept the designation of the start and end of the measurement, and the processes of steps 52 to 55 may be repeated during the period from when the start of the measurement is designated to when the end of the measurement is designated.

FIG. 6 is an external view of a non-contact thickness measuring device. Non-contact thickness measuring device (in particular, optical measuring head 10)
Is small, lightweight, and excellent in portability and portability.
In addition, since the position of the optical measurement head 10 can be freely changed, it is possible to measure the thickness of the object 40 that cannot be moved or the object 40 having various shapes. Further, depending on the shape of the optical measurement head 10, as shown in FIG. 7, the measurement can be performed even when the length of the portion to be measured is short, or when there is an obstacle adjacent to the portion to be measured.

In the arithmetic and display unit 30, the arithmetic processing unit 32 and the memory 33 are realized by a computer board or a personal computer.
A display such as an RT can also be used. However, since the A / D converter is required to have high accuracy, it is preferable that the A / D converter be configured as an independent board.

The measurement accuracy can be improved by using the optical measurement head 10 and a measurement auxiliary mechanism for fixing the object 40 to be measured. FIG. 8 shows a configuration example of the measurement assisting mechanism. 8 includes a fixed base 81 having two surfaces formed at right angles, a slider 81 that supports the optical measurement head 10 on one surface of the fixed base 81 and moves horizontally, and a fixed base 81. And a support member 83 for fixing the device under test 40 (a flat plate in the figure) to the other surface. By the measurement assisting mechanism 80, the optical measurement head 10 can irradiate the laser beam vertically to the measured portion and continuously scan the measurement range S. By connecting the data output terminal 35 to a personal computer or the like and summing up the distance data La and Lb and the thickness data Lx that are continuously output, it is possible to obtain the change in the thickness of the object 40 and the degree of curvature. It is possible. Of course, this function may be provided to the arithmetic processing unit 32 of the arithmetic display device 30 so that the totaling result is selectively displayed on the display unit 34. In this case, the distance data L
a and Lb and thickness data Lx are stored in the memory 33,
After the measurement is completed, these should be totaled.

Next, another embodiment of the present invention will be described.

In the non-contact thickness measuring apparatus according to the present embodiment, as shown in FIG. 9, the optical measuring head 10 has four optical measuring sensors 11a, 11b, 11c and 11d. Further, the A / D converter 31 of the arithmetic and display unit 30 has four blocks including an A / D conversion circuit corresponding to each optical measurement sensor, and outputs distance data Da, Db, Dc, and Dd. . Other configurations are the same as the embodiment of FIG.

The arrangement relationship between the optical measurement sensors 11a and 11b is the same as that described in the embodiment of FIG. The optical measurement sensors 11c and 11d have the same arrangement relationship, but are arranged such that the optical axes of the two laser beams are parallel to each other at a distance Y as shown in FIG. The data of the distance Y is also stored in the ROM of the arithmetic processing unit 32.

The arithmetic processing unit 32 of the arithmetic and display unit 30 calculates the measured object 4 based on the measurement results of these four optical measurement sensors.
Correct the inclination of 0 to calculate an accurate thickness. In FIG.
4 shows a flowchart of a process performed by a calculation processing unit 32 of the calculation display device 30.

After the power is turned on, the arithmetic processing section 32 reads the distance data Da, Db, Dc, and Dd measured at the same time and corrects them (step 61). Then, two thicknesses L1 and L2 of the measured object 40 are calculated (step 62). The thicknesses L1 and L2 are calculated in the same manner as described with reference to FIG. Next, the arithmetic processing unit 3
2 compares the thicknesses L1 and L2 (step 6
3). When the difference between the two is equal to or less than the predetermined error amount, the inclination angle θ1 of the DUT 40 = tan −1 ((La−Lc) / Y).
Is calculated (step 64), and the corrected thickness Lh = L1 × co
sθ1 is calculated (step 65). Then, the arithmetic processing section 32 causes the display section 34 to display the calculated corrected thickness Lh (Step 66), and returns the processing to Step 61.
If the difference between the thicknesses L1 and L2 exceeds the predetermined error amount in step 63, the arithmetic processing unit 32 displays the display unit 34
Is displayed (step 67), and the process returns to step 61.

As described above, in the non-contact thickness measuring apparatus of the present embodiment, based on the distance data obtained by one measurement,
The thickness Lh in which the inclination of the device under test 40 has been corrected can be calculated. That is, a highly accurate thickness can be calculated in a short time. Of course, as in the embodiment of FIG. 5, the processing of steps 61 to 65 may be repeated a plurality of times to display the minimum corrected thickness Lh.

Note that the optical measurement sensor 11d may be omitted from the configuration of the optical measurement head 10. Also in this case, for the DUT 40 having a uniform thickness, the thickness Lh in which the inclination is corrected can be calculated and displayed.

Further, it is possible to perform correction for a three-dimensional inclination. Specifically, for example, the position of the reflection mirror 12d is moved to the optical measurement sensor 11d side, and the optical axis of the laser light of the optical measurement sensor 11c at the insertion port 13 is
In parallel, shift upward by Z. Then, the inclination angle θ2 = t
an-1 ((X- (Lc + Ld + L1)) / Z)
The thickness Lh may be calculated from L1 × cos θ1 × cos θ2.

[0029]

As described above, according to the present invention, it is possible to provide a non-contact thickness measuring device capable of relaxing the limitation of the shape of a measurable object and performing a highly accurate measurement. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a non-contact thickness measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the principle of thickness measurement by an optical measurement sensor.

FIG. 3 is a diagram showing an internal configuration of an optical measurement head.

FIG. 4 is a block diagram illustrating a configuration of an A / D converter.

FIG. 5 is a flowchart illustrating processing contents of an arithmetic processing unit.

FIG. 6 is a view showing the appearance of a non-contact thickness measuring device.

FIG. 7 is a diagram illustrating an example of insertion of an object to be measured into an optical measurement head.

FIG. 8 is a diagram showing a configuration of a measurement assisting mechanism.

FIG. 9 is a configuration diagram of an optical measurement head of a non-contact thickness measurement device according to another embodiment of the present invention.

FIG. 10 is a diagram showing the principle of thickness measurement by an optical measurement sensor.

FIG. 11 is a flowchart illustrating processing performed by an arithmetic processing unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Optical measuring head, 20 ... Cable, 30 ... Operation display device, 40 ... DUT, 11a, 11b, 11
c, 11d: Optical measurement sensor, 12a, 12b, 12
c, 12d: reflection mirror, 31: A / D converter, 32
... arithmetic processing unit, 33 ... memory, 34 ... display unit, 35
.. Data output terminals, Ba, Bb, Bc, Bd... Laser light, 80... Measurement assisting mechanism, 81... Fixed base, 81.

Claims (8)

[Claims] 1. An object to be measured comprising two light measuring sensors for outputting a light beam and outputting a signal having a magnitude proportional to the length of the light beam to the object from the displacement of the reflected light of the light beam. An optical measurement head having an insertion opening through which an optical signal is inserted, and an A / D conversion unit that individually captures signals output from the two optical measurement sensors via a cable and converts the signals into digital data in parallel. A display unit, and an arithmetic processing unit that calculates thickness data representing the thickness of the object to be measured based on digital data converted from signals output from the two optical measurement sensors at the same time and displays the thickness data on the display unit A non-contact thickness measuring device, comprising: a calculation display device having: 2. The non-contact thickness measuring device according to claim 1, wherein at the insertion opening of the optical measuring head, the light beams output from the two optical measuring sensors travel in the opposite direction on the same optical axis. Non-contact thickness measuring device. 3. The non-contact thickness measuring device according to claim 1, wherein the optical measuring head is arranged beside the insertion opening, and adjusts a direction of a light beam output from the light measuring sensor and a reflected light of the light beam. A member for changing is provided corresponding to each optical measurement sensor, and the two optical measurement sensors are arranged so as to output a light beam in a direction opposite to the insertion direction of the object to be measured. Non-contact thickness measuring device. 4. The non-contact thickness measuring device according to claim 1, wherein the arithmetic processing unit causes the display unit to display minimum thickness data among a plurality of thickness data continuously obtained by the arithmetic operation. A non-contact thickness measuring device, 5. The non-contact thickness measuring apparatus according to claim 1, wherein a fixed base, a slider for horizontally moving the optical measurement head on the fixed base, and an object to be measured fixed to the fixed base. The slider and the support member, so that the object to be measured is vertically irradiated with a light beam output from the optical measurement sensor,
A non-contact thickness measuring device, wherein the optical measurement sensor and the object to be measured are arranged on a fixed base. 6. An optical measurement sensor comprising: three or more optical measurement sensors for outputting a light beam and outputting a signal having a magnitude proportional to the length of the light beam to the object from the displacement of the reflected light of the light beam; An optical measurement head having an insertion opening into which an object is inserted; an A / D conversion unit that individually captures signals output from the optical measurement sensors via a cable and converts the signals into digital data in parallel; A display unit, based on digital data converted from a signal output from each of the optical measurement sensors at the same time, thickness data representing the thickness of the measured object, and angle data representing the inclination of the measured object with respect to the light beam. A non-contact thickness measurement device, comprising: a calculation processing device that calculates the thickness data based on the angle data, corrects the thickness data with the angle data, and displays the corrected data on the display unit. 7. The non-contact thickness measuring device according to claim 6, wherein at the insertion opening of the optical measurement head, light beams output from at least two optical measurement sensors among the optical measurement sensors have the same optical axis. A non-contact thickness measuring device characterized by proceeding in the opposite direction on the top. 8. The non-contact thickness measuring device according to claim 6, wherein the optical measurement head is arranged beside the insertion port, and adjusts a direction of a light beam output from the light measurement sensor and a reflected light of the light beam. A member for changing is provided corresponding to each of the optical measurement sensors, and each of the optical measurement sensors is arranged to output a light beam in a direction opposite to the insertion direction of the device to be measured. Non-contact thickness measuring device.