JP2000266517A - Method for measuring glass tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the concentricity of glass tubes having different light transmission coefficients and outside diameters and those made of crystallized glass which only transmits infrared rays. SOLUTION: In a method for measuring glass tube, a glass tube 1 is scanned with a laser beam 2 and the variation of the light quantity of the beam 2 which occurs in both edge sections 1c and 1d of the outer periphery 1a and both edge sections 1e and 1f of the internal hole 1b of the tube 1 is detected and converted into voltage signals S1 by means of a sensor 8. Then center positions 1h and 1i of the outer periphery 1a and internal hole 1b are calculated by measuring the period of time required for detecting both edge sections 1c and 1d and 1e and 1f at the positions where the voltage signals S1 become signal levels V1 and V2 and the concentricity of the tube 1 is measured from the distance between the center positions 1h and 1i. The signal level V2 is adjusted in accordance with the light quantity of the laser beam 2 transmitted through the glass tube 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring concentricity of a glass tube using a laser beam.

[0002]

2. Description of the Related Art Conventionally, the concentricity of a glass tube is measured as follows. As shown in FIG. 5, a red laser beam 2 having a wavelength of about 680 nm emitted from a laser light source 4 of a laser measuring device 3 is deflected by a deflecting means 5 composed of a rotatingly driven or reciprocally driven reflector having a reflecting mirror. The laser beam 2 is deflected at a predetermined cycle, and the deflected laser beam 2 is made parallel by a collimator lens 6 to scan at right angles to the axial direction of the glass tube 1. Of the laser beam 2 generated at both edges of the outer periphery 1a and the inner hole 1b of the glass tube 1,
And converts it into a voltage signal S1. In the processing unit 9, the fall R of the voltage signal S1 in the portion where the glass tube 1 is scanned is
1. The signal peaks P1, P2, P3, the rising R2 and the predetermined signal level V1 intersect to form an intersection. Of these intersections, the intersection is the edge portions 1d and 1c of the outer circumference 1a, and the intersection is the edge portion 1 of the inner hole 1b.
e, 1f, respectively, and the time of intersection corresponding to the center position 1h of both edges 1c, 1d of the outer circumference 1a is calculated by averaging the time of detection of the intersection and the time of detection of the intersection. The detected time of the intersection and the detected time of the intersection are averaged to calculate a time ti corresponding to the center position 1i of both edges 1e and 1f of the inner hole 1b, and the time required from the time to to the time ti is calculated as the length. From the center position 1h of the outer periphery 1a of the glass tube 1 to the center position 1 of the inner hole 1b.
Calculate the distance to i. The concentricity of the glass tube 1 is obtained by performing such measurement processing on the outer periphery 1a of the glass tube 1 in a plurality of directions. The output concentricity value is displayed on the display unit 10.

[0003]

However, when the light transmittance of the glass tube changes greatly, as shown in FIG. 5C, the laser beam 2 passing through the central portion of the glass tube 1
a, the change in the light amount is detected by the sensor 8 and converted into an electric signal S1a.
Is lower than the signal level V1, and no intersection occurs, and the intersection which originally corresponds to one edge 1d of the outer periphery 1a and has the sixth predetermined signal level V1 is defined as the inner hole 1b.
There is a problem that the time ti corresponding to the center position 1i of the inner hole 1b of the glass tube 1 cannot be calculated as an intersection point corresponding to the edge portion 1f of the glass tube 1 by mistake.

When the glass tube 1 is made of crystallized glass exhibiting milky white color and the light transmittance of visible light is very low, when the conventional red laser beam 2 having a wavelength of about 680 nm is used for scanning, the laser beam is scanned. 2a and the like do not sufficiently pass through the glass tube 1, and the signal peaks P1, P2, and P3 of the voltage signal S1 obtained by scanning the glass tube 1 become low, and FIG.
Similarly to (C), both edges 1e and 1f of the inner hole 1b cannot be detected, and a time ti corresponding to the center position 1i of the inner hole 1b.
Cannot be calculated.

An object of the present invention is to provide a method for measuring the concentricity of a glass tube which solves the above-mentioned conventional problems.

[0006]

According to the glass tube measuring method of the present invention, a laser beam is scanned at right angles to the axial direction of the glass tube and in a plurality of directions around the outer periphery of the glass tube. The sensor detects changes in the amount of laser light generated at both edges of the outer and inner holes and converts them into electric signals.Then, the position where the electric signal reaches a predetermined signal level is determined, and the outer and inner holes of the glass tube are detected. Detect both edge portions, calculate the center position of the outer periphery and the inner hole from the position of one edge portion and the position of the other edge portion, and calculate the center position of the outer hole and the center position of the inner hole from the distance between the center position of the outer periphery and the center position of the inner hole. In the method for measuring a concentricity of a glass tube, the signal level for detecting both edges of the inner hole is adjusted according to the amount of a laser beam transmitted through the glass tube.

Further, according to the glass tube measuring method of the present invention, when adjusting the signal level for detecting the edge portion of the inner hole, the measuring position of the light quantity which is the reference of the laser beam transmitted through the glass tube is set outside the glass tube. It is characterized in that it is adjusted according to the diameter dimension.

Further, the method for measuring a glass tube according to the present invention comprises:
The glass tube is made of crystallized glass that transmits light in the infrared region, and the wavelength of the laser beam transmitted through the glass tube is 100.
It is characterized by being at least 0 nm.

[0009]

According to the method for measuring a glass tube of the present invention, the signal level for detecting both edges of the inner hole is adjusted in accordance with the amount of laser beam transmitted through the glass tube. The task of manually adjusting the signal level at which the laser beam is detected at both edges of the inner hole, which was performed every time the light transmittance of the tube changes, is no longer necessary, and the center of the inner hole of the glass tube having a different light transmittance for the laser beam is eliminated. The position can be measured accurately.

Further, according to the method for measuring a glass tube of the present invention, when adjusting the signal level for detecting the edge portion of the inner hole, the measurement position of the reference light amount of the laser beam transmitted through the glass tube is set to the glass tube. Adjustment according to the outer diameter of the glass tube eliminates the need to manually adjust the measurement position of the reference light amount of the laser beam transmitted through the glass tube, which was performed every time the outer diameter of the glass tube changes, It is possible to accurately measure the center position of the inner hole of a glass tube having a different outer diameter.

According to the method for measuring a glass tube of the present invention, the glass tube is made of crystallized glass that transmits light in the infrared region, and the wavelength of the laser beam transmitted through the glass tube is one.
Since it is 000 nm or more, the center position of the inner hole of the glass tube made of crystallized glass, which could not be measured conventionally, can be accurately measured.

[0012]

FIG. 1 is an explanatory view of an embodiment of the present invention, in which (A) is a conceptual diagram of a laser measuring device,
(B) is an explanatory view of a laser beam that scans the glass tube. In this figure, 1 is a glass tube, 2 is a laser beam,
3 is a laser measuring device, 4 is a laser light source, 5 is a deflecting means of the laser beam 2, 6 is a collimator lens of the laser beam 2, 7 is a condenser lens of the laser beam 2,
Reference numeral 8 denotes a sensor that converts the laser beam 2 into a voltage signal S1, and reference numeral 9 denotes a processing unit that calculates the center position 1h of the outer periphery 1a of the glass tube 1 and the center position 1i of the inner hole 1b and converts the voltage signal S1 into concentricity. Reference numerals 10 and 10 denote display units for displaying the concentricity of the glass tube 1 calculated by the processing unit 9, respectively. FIG. 2 is an explanatory diagram of the inside of the processing unit 9 when the light transmittance of the glass tube 1 changes. FIG. 3 is an explanatory diagram when the outer diameter of the glass tube 1 changes. FIG. 4 shows a laser beam having adjusting means 11 for adjusting the measuring position 1g of the light quantity of the laser beam 2 passing through the glass tube 1 according to the outer diameter dimension of the glass tube 1 and transmitting the measuring position 1g of the glass tube 1. FIG. 9 is an explanatory diagram of a circuit 9a of a processing unit 9 that detects a VP value that changes according to the light amount of No. 2 and adjusts a signal level V2.

As shown in FIG. 1, a laser measuring device 3 used in an embodiment of the present invention is provided with a laser light source 4 for emitting a laser beam 2 having a wavelength of 1550 nm using a laser diode, and a reflecting mirror. Deflecting means 5 for reflecting the laser beam 2 emitted from the laser light source 4 by rotating or oscillating the reflector;
A collimator lens 6 for collimating the laser beam 2 deflected by the deflecting means 5 and scanning at right angles to the axial direction of the glass tube 1; a condenser lens 7 for condensing the laser beam 2 transmitted through the glass tube 1; A sensor 8 for converting the laser beam 2 condensed by the optical lens 7 into a voltage signal S1, and detecting both edges 1c and 1d of the outer periphery 1a at a point where the voltage signal S1 reaches the signal level V1, and averaging each detection time. The processing is performed to calculate a time to corresponding to the center position 1h of the outer periphery 1a, to detect both edges 1e and 1f of the inner hole 1b at a point where the voltage signal S1 becomes the signal level V2, and to average each detection time. Then, a time ti corresponding to the center position 1i of the inner hole 1b is calculated, and Δt of a difference between the time to and the time ti is converted into a distance K having a unit of length using a high-resolution clock pulse or the like. Measurement processing A processing unit 9 for performing processing in all directions of the outer periphery 1 a of the lath tube 1, calculating a maximum movement distance of the center position 1 i with respect to the center position 1 h as the concentricity of the glass tube 1, and glass converted by the processing unit 9 A display unit 10 for displaying the concentricity of the tube 1. Laser measuring device 3
Has the above-described configuration, and the glass tube 1 is
And the glass tube 1 is rotated twice at a rotation speed of 12 rpm using a rotating means (not shown) by positioning the glass tube 1 at a right angle to the scanning direction of the laser beam 2 within the scanning range. Thus, data of 10,000 points is collected.

In the method for measuring a glass tube according to the present invention, as shown in FIG. 1, the measurement position of the reference light amount of the laser beam 2 passing through the glass tube 1 is set to the measurement position 1g where the light amount is the largest.
Then, the voltage of the voltage signal S1 corresponding to the measurement position 1g becomes VP. This voltage VP changes in conjunction with the light transmittance of the glass tube 1. If the signal level V2 is set to a constant ratio between 40% and 60% with respect to the voltage VP, for example, 50%, the signal level V2 and the voltage signal S1 stably form an intersection. Even when the light transmittance changes, both edges 1e, 1f of the inner hole 1b are stably maintained.
Can be detected, and an accurate time ti corresponding to the center position 1i can be calculated. For example, as shown in FIG. 2, when the light transmittance of the glass tube 1 decreases and the voltage signal S1 changes like the voltage signal S1a, the voltage VP
Changes to the voltage VP ', and the signal level V2
Is set to the signal level V2 ', the signal level V
2 ′ and the voltage signal S1a stably form an intersection or an intersection, and the time ti corresponding to the center position 1i of the inner hole 1b can be calculated.

However, when the measurement position 1 g of the reference light amount of the laser beam 2 passing through the glass tube is fixed, as shown in FIG. 3, when the outer diameter of the glass tube 1 is within the predetermined measurement range D1. The voltage signal S1 and the signal level V2 intersect and the inner diameter can be measured. However, if the outer diameter dimension is increased to exceed the measurement range D1 and become a size like the glass tube 20, the following is performed. Problems arise.

When the outer diameter size increases, the voltage signal S1 of the glass tube 1 changes from the voltage signal S1 to the voltage signal S1b of the glass tube 20, and the light amount of the laser beam decreases at the measurement position 1g where the measurement position of the light amount is fixed. If the signal level V2 'is determined at a fixed ratio with respect to the voltage VP' corresponding to the light amount, the signal level V2 'does not intersect with the signal S1b, and the calculation of the center position 1i of the inner hole 1b becomes impossible. for that reason,
The measurement range is expanded to D2 and the measurement position of the light amount is from 1g to 1j.
Adjustment work is required. On the other hand, when the outer diameter of the glass tube becomes very small with respect to the set measurement range, it is necessary to adjust the measurement range to the optimum measurement range and the optimum light amount measurement position.

A preferred method for measuring a glass tube according to the present invention is as follows.
Signal level V2 for detecting both edges 1e and 1f of the inner hole
Is adjusted in accordance with the outer diameter of the glass tube in order to adjust the measurement position of the reference light amount of the laser beam 2 passing through the glass tube.

Next, when measuring the concentricity of the glass tube 1, first, as shown in FIG. 1, the glass tube 1 is moved in the scanning range of the laser beam 2 within the scanning range of the laser beam 2. Position so that the directions are at right angles.

Next, a change in the light amount of the laser beam 2 generated at both edges 1c and 1d of the outer periphery 1a of the glass tube 1 and both edges 1e and 1f of the inner hole 1b is detected by the sensor 8 and converted into a voltage signal S1. Then, as shown in FIG. 4, a waveform having a falling R1, a signal peak P1, a signal peak P2, a signal peak P3, and a rising R2 is obtained in a portion of the processing unit 9 where the voltage signal S1 has passed through the glass tube 1. The intersection between the falling R1 and rising R2 of the voltage signal S1 and the signal level V1 occurs. This signal is shaped into a waveform and output as a rectangular voltage signal S2. The rising time of the rectangular voltage signal S2 is the detection time t1 of the edge portion 1c of the outer periphery 1a, and the falling time of the voltage signal S2 is the edge portion. The detection time t2 of 1d is reached, and by averaging the times t1 and t2, the center position 1 of the outer circumference 1a is obtained.
The time to corresponding to h is calculated.

Next, as adjusting means 11 for adjusting the measurement position 1g of the light amount of the laser beam 2 transmitted through the glass tube 1 according to the outer diameter of the glass tube 1, first, the falling time of the voltage signal S2 is set to t1. Then, a time t3 at which the signal peak P1 starts rising and a time t4 at which the signal peak P3 ends falling are set, and a rectangular voltage signal S3 is obtained by waveform shaping. Next, the voltage signal S1 is sampled by the voltage signal S3, and the voltage signal S1 is sampled within a range from time t3 to time t4.
1 is performed, the position of the inflection point is specified, and the time tP at which the voltage of the signal peak P1 becomes highest is obtained. The position corresponding to this time tP is the light amount measurement position 1g.
For the measured voltage VP, the signal level V2 always crosses the voltage signal S1 from the intersection to the intersection, for example, the voltage VP
Set to 50% of the voltage.

Next, a signal generated at the intersections of the voltage signal S1 and the signal level V2 at intersections is shaped into a rectangular voltage signal S4, and the voltage signal S4 is shaped into a rectangular voltage. A signal S5 is output, and the detection time t5 of the intersection corresponding to the edge 1e of the inner hole 1b and the detection time t6 of the intersection corresponding to the edge 1f are averaged to obtain a time corresponding to the center position 1i of the inner hole 1b. ti is calculated.

Next, the center position 1 of the outer periphery 1a of the glass tube 1
The time Δt between the time to corresponding to h and the time ti corresponding to the center position 1 i of the inner hole 1 b is converted into a length using a high-resolution clock pulse or the like, and the center of the outer circumference 1 a in one measurement direction of the glass tube 1 is converted. The distance K of the center position 1i of the inner hole 1b is calculated based on the position 1h. A series of measurement processes is performed by rotating the glass tube 1 twice around the tube axis to make the glass tube 1
By performing the measurement 00 times, the time to of the center position 1h is
The distance K in the range in which the time ti at the center position 1i is delayed
Is detected, and the negative minimum value of the distance K in the range where the time ti is earlier than the time to is detected, and the difference is calculated as the concentricity of the glass tube 1. The calculated concentricity is output to the display unit 10 and displayed.

As described above, glass tubes having different light transmittances for the laser beam 2 in the range of 80 to 90%, an outer diameter of 1.0 to 5.0 mm, and an inner diameter of 0.05 The concentricity of the glass tubes 1 having different dimensions in the range of 0.5 mm was measured.

Further, it has a milky white color, has a thickness of 1 mm, and emits 5% of light having a wavelength of 900 nm in the infrared region and a wavelength of 1500 nm.
A laser beam 2 having a wavelength of 1550 nm is scanned using a laser diode as a laser light source 4 on a glass tube 1 made of crystallized glass that transmits 75% of the light and 80% or more of the light having a wavelength of 1600 nm. The degree was measured.

In the method for measuring a glass tube according to the embodiment of the present invention, a glass tube having a different light transmittance in a range of 80 to 90% for a laser beam under an environment of 20 ± 5 ° C. The concentricity of each of glass tubes of different dimensions having an outer diameter in the range of 1.0 to 5.0 mm and an inner diameter in the range of 0.1 to 0.5 mm, and a glass tube made of crystallized glass that transmits light in the infrared region. Measurement range in the optical axis direction ±
Within 0.2 mm, linearity ± 0.1 μm, reproducibility ± 0.5
The measurement could be performed with an accuracy within μm.

[0026]

According to the method for measuring a glass tube of the present invention,
Accurately measure the concentricity of glass tubes with different light transmittances for laser beams, glass tubes with different outer diameters, and glass tubes made of crystallized glass that transmits infrared light while transmitting little visible light This has a practically excellent effect.

[Brief description of the drawings]

1A and 1B are explanatory diagrams of a method for measuring a glass tube according to the present invention, wherein FIG. 1A is a conceptual diagram of a laser measuring device, and FIG. 1B is an explanatory diagram of a laser beam that scans a glass tube.

FIG. 2 is an explanatory diagram of the present invention, and is an explanatory diagram of an output pattern of a processing unit when a light transmittance of a glass tube changes.

FIG. 3 is an explanatory diagram of the present invention, illustrating the necessity of adjusting a measurement position of a light amount serving as a reference of a laser beam according to an outer diameter.

4A and 4B are explanatory diagrams of a processing unit, where FIG. 4A is a conceptual circuit diagram of signal processing, and FIG. 4B is a diagram illustrating a signal pattern.

FIG. 5 is an explanatory view of a conventional method for measuring a glass tube,
(A) is a conceptual diagram of a laser measuring device, (B) is an explanatory diagram of a laser beam that scans a glass tube, and (C) is an explanatory diagram of an output pattern of a conventional processing unit.

[Description of Signs] 1,20 Glass tube 1a Outer circumference 1b Inner hole 1c, 1d, 1e, 1f Edge 1h, 1i Center position 1g, 1j Measurement position 2 Laser beam 3 Laser measuring device 4 Laser light source 5 Deflection means 6 Collimator lens 7 Condensing lens 8 Sensor 9 Processing unit 9a Circuit 10 Display unit 11 Adjusting means D1, D2 Measurement range P1, P2, P3 Signal peak S1, S1a, S1b, S2, S3, S4, S5 Voltage signal V1, V2, V2 'signal level

Claims (3)

[Claims] A laser beam is scanned at right angles to the axial direction of the glass tube and in a plurality of directions with respect to the outer periphery of the glass tube, and the light amount of the laser beam generated at both edges of the outer periphery and the inner hole of the glass tube. The sensor detects the change in the position of the glass tube and converts it into an electric signal. The position where the electric signal reaches a predetermined signal level is detected to detect both edges of the outer periphery and the inner hole of the glass tube. And calculating the center position of each of the outer periphery and the inner hole from the position of the other edge portion and measuring the concentricity from the distance between the center position of the outer periphery and the center position of the inner hole. A method for measuring a glass tube, wherein the signal level for detecting both edge portions is adjusted according to the amount of a laser beam transmitted through the glass tube. 2. A method for adjusting a signal level for detecting an edge portion of an inner hole, wherein a measuring position of a reference light amount of a laser beam transmitted through a glass tube is adjusted according to an outer diameter of the glass tube. The method for measuring a glass tube according to claim 1. 3. The glass according to claim 1, wherein the glass tube is made of crystallized glass that transmits light in an infrared region, and a wavelength of a laser beam transmitted through the glass tube is 1000 nm or more. Tube measurement method.