JP2000180130A - Glass tube drawing device with tube diameter measuring instrument, and tube diameter measuring method for glass tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the glass tube drawing device with the tube diameter measuring instrument which can measure tube diameters including the internal diameter of a glass tube without contacting and measure the tube diameter in a tube drawing process and improves the quality and yield by feeding the result back to the tube drawing device, and the tube diameter measuring method for the glass tube. SOLUTION: The tube diameter measuring instrument is equipped with a light irradiating means 4 which irradiates a drawn glass tube with slit light obliquely to the tube drawing direction, an image pickup means 5 which is installed obliquely opposite the light irradiating means in the tube drawing direction and picks up an image of the irradiation light from the light irradiating means having passed through the glass tube, and a tube diameter calculating means 7 which calculates the tube diameter of the glass tube according to the picked-up image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe diameter measuring apparatus comprising a glass pipe drawing apparatus for drawing a glass tube, and a pipe diameter measuring apparatus for measuring the diameter of the drawn glass tube in a drawn state. And a method for measuring the diameter of a glass tube for measuring the diameter of the glass tube.

[0002]

2. Description of the Related Art Generally, a glass tube such as a glass tube for a fluorescent lamp is continuously drawn by a glass tube drawing device, cut into a predetermined length, and subjected to a shaping process such as drawing at both ends. Has been commercialized. In the glass tube drawn by such a glass drawing apparatus, the outer diameter and the inner diameter are measured to determine whether the outer diameter and the inner diameter are within a predetermined value or a predetermined allowable range,
When the measurement result deviates from the predetermined value, the operation of the glass tube drawing device is controlled so that the operation falls within a predetermined value or a predetermined allowable range.

Conventionally, as shown in FIG. 8, after cutting a glass tube 100, an outer diameter and an inner diameter are measured using a caliper 101. Further, as described in JP-A-5-52530, after the glass tube is cut, the dimensions and the outer diameter are measured from the image of the glass tube by an illumination device and a CCD image sensor.

[0004]

In the conventional measuring apparatus and method, the calipers are so-called contact-type measurements in which the calipers are brought into contact with a glass tube, so that the glass tube is scratched or chipped. Sometimes. In addition, it cannot be easily automated due to manual work. Further, since the measurement is performed after cutting the drawn glass tube, the measurement result is fed back to the drawing device, and the drawing speed and the drawing temperature are set so that the outer diameter and the inner diameter of the glass tube become desired values. Cannot be controlled in real time. Therefore, it is difficult to improve the quality and yield of the glass tube by using a caliper.

Further, in the apparatus described in Japanese Patent Application Laid-Open No. 5-52530, the outer diameter of a glass tube can be measured, but the inner diameter cannot be measured. In addition, since the measurement is performed after cutting the drawn glass tube, the measurement result as described above is fed back to the drawing device, and the drawing speed is adjusted so that the outer diameter and the inner diameter of the glass tube become desired values. There is a technical problem that it is not possible to control the pipe drawing temperature in real time. Further, since at least two CCD image sensor cameras and a mechanism for rotating the glass tube are required, there is a technical problem that the number of components is large and the structure is complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned technical problem, and can measure the diameter of a glass tube including the inner diameter thereof in a non-contact manner, and can measure the diameter of the glass tube during drawing. The object of the present invention is to provide a glass pipe drawing apparatus having a pipe diameter measuring apparatus designed to improve quality and yield by feeding back to a pipe drawing apparatus and a method for measuring the diameter of a glass pipe. is there.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned technical problems, a tube diameter measuring apparatus according to the present invention comprises: a glass tube drawing apparatus for drawing a glass tube; A pipe diameter measuring device having a pipe diameter measuring device for measuring in a drawn state, wherein the tube diameter measuring device slits the glass tube drawn obliquely with respect to the tube drawing direction. Light irradiating means for irradiating light in the shape of a light, and an imaging device which is installed at a position obliquely opposite to the light irradiating means with respect to the pipe drawing direction and which captures an image of irradiation light from the light irradiating means which has passed through the glass tube. Means, and a pipe diameter calculating means for calculating a pipe diameter of the glass tube based on the taken image.

Here, the tube diameter calculating means includes detecting means for continuously detecting the brightness of the picked-up image in the vertical direction, and scanning means for scanning the detecting means in the horizontal direction. It is desirable to calculate the integrated value of the luminance in the horizontal direction of the glass tube from the luminance distribution in the vertical direction of the glass tube at each position, and calculate the tube diameter of the glass tube from the integrated value. A comparing means for comparing the pipe diameter calculated by the pipe diameter calculating means with a preset value; and a drawing control means for controlling a drawing operation in the glass drawing apparatus based on a comparison result of the comparing means. It is desirable to have.

A method for measuring the diameter of a glass tube according to the present invention, which has been made to solve the above technical problem, is a method for measuring the diameter of a glass tube drawn by a drawing apparatus. A light irradiation step of irradiating the drawn glass tube with a slit-like light obliquely to a drawing direction, and irradiating the irradiation light irradiated by the light irradiation step passing through the glass tube. It is characterized by comprising an imaging step of imaging as an image at a position obliquely opposed to the pulling direction, and a pipe diameter calculating step of calculating the diameter of the glass tube based on the captured image.

Here, the tube diameter calculating step includes a step of continuously detecting the brightness of the captured image in the vertical direction;
A scanning step of scanning the detection step in the horizontal direction,
It is preferable that an integrated value of the luminance in the horizontal direction of the glass tube is calculated from the luminance distribution in the vertical direction of the glass tube at each position in the horizontal direction, and the tube diameter of the glass tube is calculated from the integrated value. A comparison step of comparing the pipe diameter calculated in the pipe diameter calculation step with a preset value; and a pipe drawing control step of controlling a pipe drawing operation in the glass pipe drawing apparatus based on a comparison result of the comparison step. It is desirable to provide.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing the overall configuration of a glass tube drawing apparatus having a tube diameter measuring apparatus, wherein reference numeral 1 denotes a drawing furnace, 2 denotes a pair of right and left rollers, and Construct a pipe drawing device. The tube drawing furnace 1
Is composed of a heating device 11 for melting the quartz, a leading rod 12 for leading the fused quartz, and an upper lid 13. Reference numeral 3 denotes a glass tube drawn from the glass tube drawing device, and reference numeral 4 denotes a light irradiation device for irradiating the glass tube 3 drawn with slits with light. It is installed to be.

Reference numeral 5 denotes an image pickup device such as a CCD camera installed at a position opposite to the light irradiation device 4 via the glass tube 3, and irradiation light from the light irradiation device 4 passing through the glass tube 3. Is captured as an image oblique to the pipe drawing direction. The light irradiation device 4 and the imaging device 5 are provided in a dark room 10.
It is installed in. Reference numeral 6 denotes an image processing device that processes an image of the irradiation light captured by the imaging device 5, and reference numeral 7 denotes an outer diameter and an inner diameter of the glass tube 3 based on a signal processed by the image processing device 6. An arithmetic processing unit, such as a personal computer that calculates the thickness,
Reference numeral 8 denotes a display device that displays an image captured by the image pickup device 5 and an arithmetic processing process of the arithmetic processing device 7, a luminance integrated value characteristic described later, an arithmetic processing result, and the like. Numeral 9 denotes an arithmetic result from the arithmetic processing device 7. This is a drawing control device for controlling the operation of the drawing speed, the drawing temperature, and the like for the glass drawing device including the drawing furnace 1 and the rollers 2 based on. In addition,
In the drawing, 31a is a powdery quartz loaded in the drawing furnace 1;
1 b is quartz fused by the heating device 11.

As shown in FIG. 2, the image processing apparatus 6 includes a sampling circuit 61, an A / D converter 62, a frame memory 63, a write address generator 64, and a read address generator 65.

Next, the operation of this embodiment will be described. First, powdered quartz 31a is charged into the drawing furnace 1 and heated by the heating device 11, and when the temperature reaches about 2000 ° C., the powdered quartz 31a becomes fused quartz 32b. In the above state, by pulling out the drawing rod 12 upward, the drawing hole of the tube drawing furnace 1 is opened and the fused quartz 3 is drawn from below.
1b is led out to the outside as a glass tube 3 having translucency. The temperature at this time was about 1400 ° C, and the tube diameter was φ4
~ Φ40. The drawn glass tube 3 is drawn by a pair of rollers 2.

As described above, in a state where the glass tube 3 is continuously drawn by the glass drawing device, the light irradiation device 4 continuously irradiates the slit-shaped light to the drawn glass tube 3. I do. The irradiation light that has passed through the glass tube 3 is captured as an image by the imaging device 5 according to an instruction from the arithmetic processing device 7, and the image data is taken into the image processing device 6. At this time, since the slit-like illumination is radiated obliquely to the glass tube 3 by the light irradiation device 4,
As shown in FIG. 4, the image of the irradiation light imaged by the imaging device 5 looks like a curve at the edge of the inner diameter of the glass tube 3.

The image processing device 6 samples an analog image signal obtained from the image pickup device 5 by a sampling circuit 61, converts it into a digital signal by an A / D converter 62, and quantizes it. The quantized digital image data, that is, pixel data is input to the frame memory 63. The frame memory 63 is one frame (one screen)
The image data is sequentially written by a write address signal generated by a write address generator 64. Further, the image data is sequentially read out by the read address signal generated from the read address generator 65 and supplied to the arithmetic processing unit 7 to display the image of the irradiation light passing through the glass tube 3 as shown in FIG. indicate.

Further, for the calculation processing of the pipe diameter calculation to be described later, the read address generator 64
Is subjected to a predetermined read control. Although not shown, a timing signal is supplied from the image processing device 6 to the arithmetic processing device 7 so as to synchronize the display device 8 to display an image. The image signal from the imaging device 5 is a monochrome signal, and the pixel data represents the luminance of the image. For example, if the quantization bit number is 8 bits, the pixel data (luminance) has 256 gradations.

Next, the calculation of the outer diameter and the inner diameter of the glass tube 3 calculated by the arithmetic processing unit 7 will be described with reference to the flowchart of the processing executed by the arithmetic processing unit 7 shown in FIG. First, the read address generator 64 is controlled so that one frame of pixel data stored in the frame memory 63 corresponds to one vertical column of pixel data in the vertical direction corresponding to the left end on the screen. A read address to be read is specified, and the pixel data (luminance data) in one vertical column is sequentially read from the frame memory 63 (step S1).

Next, the read luminance data of one column are integrated to calculate an integrated value (step S2), and the integrated value is stored in a storage device provided in the arithmetic processing unit 7 (step S3). This storage device is set so that this integrated value is stored for each horizontal position on one screen. Subsequently, a read address corresponding to one vertical column of pixel data in the adjacent right vertical direction is designated, and the vertical one column of pixel data is sequentially read from the frame memory 63 (step S4). One column of luminance data is integrated to calculate an integrated value (step S5), and this is stored in the storage device of the arithmetic processing unit 7 (step S5).
6).

Next, it is determined whether the one column of pixel data read in step S4 corresponds to the right end on the screen (step S7). If the determination result is No, steps S4 to S4 are performed. By executing S6, the reading and the integration are sequentially performed on the pixel data of the adjacent right vertical column.
Through the processing of steps S1 to S6, the luminance of the image of the irradiation light that has passed through the glass tube 3 and captured by the imaging device 5 is continuously detected in the vertical direction, and the detection processing is performed in the horizontal direction. The brightness distribution in the vertical direction of the glass tube 3 at each horizontal position is determined.
Is calculated in the horizontal direction. In step S7, instead of determining the right end on the screen, a predetermined position outside the right side of the glass tube 3 may be determined.

Here, in steps S1 and S4, when one vertical column of pixel data to be read from the frame memory 63 is located outside the glass tube 3 as shown in FIG. Each luminance characteristic is as shown in FIG. That is, the luminance is high at a position corresponding to the position where the light from the light irradiation device 4 is irradiated, and otherwise the luminance is almost zero because the surroundings are dark because it is installed in a dark room.

When one vertical column of pixel data to be read is located in the glass tube 3 as shown in FIG. 5B, the luminance characteristics of this vertical column are as shown in FIG. 6B. Become. That is, since the light from the light irradiation device 4 is blocked at any of the vertical positions, the luminance in one vertical column becomes almost zero.

Further, when one vertical column of pixel data is located at the position inside the glass tube 3 as shown in FIG. 5C, the image of the irradiation light imaged as described above is curved. Each luminance characteristic in one vertical column is as shown in FIG.
The luminance is high at a position corresponding to the position where the light from the light irradiation device 4 has passed through the glass tube 3, and the luminance is almost zero at other positions because the surroundings are dark.

Therefore, the determination result of step S7 is Yes.
If this is the case, all the luminance data in one vertical line in one screen are integrated and stored, and an integrated value characteristic of the luminance in the horizontal direction of the captured image shown in FIG. 7 is created. The outside diameter, inside diameter and thickness of No. 3 are calculated (step S8).

That is, in the characteristic diagram of FIG.
Outside and inside the tube have a predetermined integrated value of luminance, and the luminance becomes almost zero in the glass tube 3. The distance from the position where the luminance becomes zero from the left end to the right of the characteristic diagram to the position where the luminance becomes a predetermined value and becomes zero and becomes the predetermined value again is the outer diameter of the glass tube 3, Is the inner diameter of the glass tube 3 from the position at which the value has become a predetermined value from zero to the position at which the luminance becomes zero. The distance from the position where the luminance becomes zero to the position where the luminance becomes a predetermined value is calculated as the thickness of the glass tube 3. Note that the characteristic diagram shown in FIG. 7 may be displayed on the display device 8 in step S8.

Next, the calculated values such as the pipe diameter and the thickness calculated in step S8 are compared with predetermined values (or predetermined ranges), and whether the calculated values match the predetermined values. Is determined (step S9). If the result of this determination is No
If so, a control signal is output to the pipe drawing control device 9 according to the determination result (step S10). When the control signal indicates that the inner diameter calculated in step S8 is smaller than the predetermined value, the rotation speed of the roller 2 is increased to increase the tube drawing speed. Alternatively, control is performed so that the heating temperature of the heating device 11 is increased to increase the tube drawing temperature. Conversely, when the calculated inner diameter is larger than a predetermined value, control is performed so as to reduce the drawing speed or to increase the drawing temperature. By such processing, the optimum drawing conditions based on the calculated result can be given to the control device 9, and the glass drawing device can be controlled in real time.

When calculating the tube diameter and the like in more detail, the image obtained from the imaging device 6 is enlarged, and the luminance distribution in the vertical direction of the glass tube 3 obtained in steps S1 to S6 is compared with the horizontal direction. It is better to divide it more finely. In addition, in order to reduce the measurement time and improve the measurement accuracy, in the horizontal division, it is preferable to finely divide the portion where the luminance change occurs from the characteristic diagram of FIG.

[0028]

As described above, according to the present invention, the tube diameter including the inner diameter of the glass tube can be measured in a non-contact manner, so that the glass tube can be prevented from being damaged. In addition, since the diameter of the glass tube can be measured during the drawing, the quality and yield can be improved by feeding back the result to the drawing device.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a glass tube drawing device having a tube diameter measuring device according to the present invention.

FIG. 2 is a diagram illustrating an embodiment of an image processing apparatus according to the present invention.

FIG. 3 is a flowchart illustrating a process performed by an arithmetic processing device according to the present invention;

FIG. 4 is a diagram showing an image obtained by the imaging device according to the present invention.

FIG. 5 is a diagram in which a vertical single straight line is added to an image obtained by the imaging apparatus according to the present invention.

FIG. 6 is a diagram illustrating luminance of pixels according to one vertical column in FIG. 5;

FIG. 7 is a diagram showing characteristics of an integrated value of luminance according to the present invention.

FIG. 8 is a diagram showing a conventional inner diameter measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drawing furnace 11 Heating device 12 Outgoing rod 13 Top lid 2 Roller 3 Glass tube 31a Powdery quartz 31b Fused quartz 4 Light irradiation device 5 Imaging device 6 Image processing device 61 Sampling circuit 62 A / D converter 63 Frame memory 64 Writing address Generator 65 Read address generator 7 Arithmetic processing unit 8 Display unit 9 Drawing control unit 10 Dark room

Claims (6)

[Claims] 1. A glass tube drawing apparatus comprising: a glass tube drawing apparatus for drawing a glass tube; and a tube diameter measuring apparatus for measuring the diameter of the glass tube in a drawn state. The pipe diameter measuring device is configured to irradiate a slit-like light obliquely to the tube drawing direction on the drawn glass tube; An imaging unit that captures, as an image, irradiation light from the light irradiation unit that has been installed at a position to pass through the glass tube,
A pipe diameter calculating device for calculating a diameter of the glass tube based on the captured image; 2. The apparatus according to claim 1, wherein said tube diameter calculating means includes: detecting means for continuously detecting the brightness of the captured image in a vertical direction; and scanning means for scanning said detecting means in a horizontal direction. 2. The integrated value of luminance in the horizontal direction of the glass tube is calculated from the luminance distribution in the vertical direction of the glass tube at each position, and the tube diameter of the glass tube is calculated from the integrated value. A glass tube drawing device having the tube diameter measuring device described in 1. 3. A comparing means for comparing a pipe diameter calculated by said pipe diameter calculating means with a preset value, and a pipe for controlling a drawing operation in said glass drawing apparatus based on a comparison result of said comparing means. 3. A glass tube drawing device having a tube diameter measuring device according to claim 1, further comprising a drawing control means. 4. A method for measuring the diameter of a glass tube drawn by a glass drawing apparatus, the method comprising: measuring a diameter of a glass tube drawn by a glass drawing apparatus; A light irradiating step of irradiating light in a shape, an imaging step of imaging the irradiation light irradiated by the light irradiating step passing through the glass tube as an image at a position obliquely opposed to a pipe drawing direction, and the imaging A tube diameter calculating step of calculating a tube diameter of the glass tube based on the obtained image. 5. The tube diameter calculating step includes a step of continuously detecting the luminance of the captured image in the vertical direction, and a scanning step of scanning the detecting step in a horizontal direction. The method according to claim 4, wherein an integrated value of luminance in a horizontal direction of the glass tube is calculated from a luminance distribution in a vertical direction of the glass tube at a position, and a tube diameter of the glass tube is calculated from the integrated value. The described method for measuring the diameter of a glass tube. 6. A tube for comparing a tube diameter calculated in the tube diameter calculation step with a preset value, and a tube for controlling a tube drawing operation in the glass tube drawing device based on a comparison result in the comparison step. The method for measuring the diameter of a glass tube according to claim 4 or 5, further comprising a pulling control step.