JPH03238307A - Outer-diameter measuring apparatus - Google Patents

Abstract

PURPOSE:To measure the very small diameter of the line of a material to be measured which is vibrated and running at a high speed, highly accurately at a high speed by synthesizing a plurality of beams, and making the distribution of light within the cross section of the beam constant. CONSTITUTION:Parallel light 4' is inputted into the side surface of a half prism 6 in the direction orthogonal to parallel light 4 and split into parallel light beams 41' and 42' at a slant surface 7. The radius of the major-axis beam, the radius of the minor-axis beam and the maximum intensity of the parallel light 4' are made equal to those of the parallel light 4. The parallel light beams 41 and 41' which are emitted in the same direction from the prism 6 become synthesized light 8. The incident angles of the parallel light beams 4 and 4' into the prism 6 are adjusted so that the optical axes of the parallel light beams 41 and 41' become parallel. The synthesized light 8 also becomes the parallel light in its optical-axis direction 21. A beam interval 46 between beam centers 47 and 47' of the parallel light beams 41 and 41' is arranged approximately equally with a beam radius 43. Then, the maximum light intensity of the synthesized light 8 becomes intensity 60 at the beam interval 46 of in a synthesizing direction 22. Thus, the intensity distribution can be made constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an outer diameter measuring device, and particularly to a measuring device that non-contactly measures the outer diameter of threads, wires, etc. running at high speed.

(Prior Art) Conventionally, methods for measuring the outer diameter without contact include a laser micrometer method, a linear sensor method, and the like. The laser micrometer type scans and focuses laser light using a polygon mirror and Fθ lens, irradiates it onto the object to be measured, and collects the transmitted light using an Fθ lens, which is then received by a sensor.The scanning speed of the laser light is kept constant. The outer diameter is measured from the time when light is blocked by the object to be measured. In the linear sensor type, a projector illuminates the object to be measured, and the transmitted or reflected light is collected by a condensing lens and received by a linear sensor. A linear sensor has a number of sensors arranged at equal intervals, and measures the outer diameter from the first sensor that receives a shielded or reflected image of the object to be measured.

Furthermore, Japanese Patent Application Laid-Open No. 55-37919 discloses a device that measures the outer diameter of a measured object by projecting a parallel beam of constant width onto the measured object and detecting the width and position where the light is blocked by the measured object. Disclosed.

(Problem to be solved by the invention) When measuring ultra-fine wire diameters, the laser micrometer type requires a very small focused laser spot, and the focal length is short (the depth of focus is short and the object to be measured is It is necessary to position within the depth of focus.Even with linear sensor type, it is necessary to shorten the focal length of the condenser lens.
I have a similar problem.

In addition, if the object to be measured moves at high speed, the measurement must also be performed at high speed, but with the laser micrometer type, there is a speed limit on the drive device that scans the laser beam, and with the linear sensor type, the There are restrictions on the readout speed of the sensor, making it difficult to perform high-speed measurements.

Furthermore, when the object to be measured travels at high speed while vibrating, and when measuring an extremely fine wire diameter, it is extremely difficult to prevent defocusing due to vibration and perform high-speed measurement.

In addition, when a laser beam is used as a parallel beam in a device that detects the amount of shading of a parallel beam, as is well known, the beam intensity distribution within the cross section of the beam forms a Gaussian distribution, which is dependent on the object to be measured. Depending on the light shielding position, there will be a difference in the amount of light shielding even though the outer diameter is the same. but,
It is extremely difficult to pinpoint the position of an extremely thin wire running at high speed.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide an outer diameter measuring device that can quickly and accurately measure the wire diameter of an extremely thin object that is vibrating and traveling at high speed.

(Means for Solving the Problems) In order to achieve the above objects, the present invention provides the following outer diameter measuring device.

In other words, two or more parallel light beams are combined when measuring the outer diameter by detecting the amount of light shielded by a linear object traveling at high speed on a parallel light beam with a constant cross-sectional outline. As a result, the light intensity distribution within the beam cross section in the direction of displacement due to vibration of the object to be measured is made constant.

Furthermore, the object to be measured is irradiated with parallel light from a laser, the transmitted light is received by a sensor, and when measuring the outer diameter, the time change of the transmitted light of the object to be measured is measured and its frequency is determined. The edge of the object to be measured is measured using two light emitting and light receiving sensors, and the width is determined by measuring the values of the two light receiving sensors and the distance between the light receiving sensors. It is used to measure large objects to be measured.

(Function) Even if laser beams have a Gaussian intensity distribution in the beam cross section, by appropriately shifting their centers and superimposing them, the cross-sectional intensity distribution of the combined beam can be made constant. In the direction perpendicular to the wire, positional displacement occurs due to vibrations caused by high-speed running, so by keeping the light intensity distribution in this direction within the beam cross section constant,
Measurement errors due to vibration etc. can be prevented.

On the other hand, since the position and outer diameter of the linear object in the running direction are almost constant, there are few problems even if the light intensity distribution in the running direction within the beam cross section remains a Gaussian distribution. If there is a small defect such as a change in the outer diameter in a part of the wire diameter, the amount of light blocking will change, but if the beam width in the running direction is small, the light blocking due to such a small defect can be reduced. Since the change in quantity gives a sharp change to the detected value, there is also the effect that it is advantageous for subsequent signal processing.

(Embodiment) The present invention will be explained based on the embodiment shown in the drawings.
Figure 3, Figure 4 are explanatory diagrams common to each embodiment, and Figure 5.
Fig. 6 and Fig. 6 are respectively the 2.3 embodiment and Fig. 7 is the 4th embodiment.
Example and Figure 8.9 are Example 5.6 and Figure 10, respectively.
The figure shows the seventh embodiment, and FIG. 11 shows the eighth embodiment.

In FIG. 1, (1) is a laser light source, which is converted into parallel light (4) by a collimating lens (2).

The laser light source (1) may itself emit parallel light or may be a diverging light source such as a semiconductor laser. In the case of the above-mentioned diverging light source, a collimating lens (2) is used to emit parallel light (
4), at this time, the optical axes are aligned and fixed to a holder to form a collimating head (3) to facilitate adjustments such as alignment of the optical axes.

The laser light source (1) is driven by measuring the optical output of the laser light source (1) with a sensor (28) so that the output is constant and stable, and feeding it back to the APC circuit (30). 28) may be built inside the semiconductor laser. [Figure 4 (a)
Reference] The sensor (28) is capable of measuring the light output of the laser light source (1), converts the amount of light received on the light receiving surface into an output current proportional to the amount of received light, and outputs the output current, such as a photodiode. , PIN diode, phototransistor, APD, and other light receiving elements can be used.

The APC circuit (30) converts and amplifies the difference between the value of the sensor (28) and the light output setting device so that the light output setting value of the laser light source (1) and the light output of the laser light source (1) are equal. The drive current of the laser light source (1) is automatically adjusted.

In Figure 2, the parallel light (4) mentioned above has a cross section of 2
The position in the dimensional direction and the distribution of light intensity form a Gaussian distribution, and the maximum light intensity (44) is at the beam center (47), and the point is 1/e'' with respect to the maximum light intensity (44). The distance between the beam center (47) and the major axis beam radius (
43).

When the laser light source (1) is a semiconductor laser, when the collimating lens (2) is used to make parallel light (4), its cross section becomes an ellipse, and the major axis beam radius of this ellipse is (43), and the minor axis beam radius is (48).

In FIG. 1, parallel light (4°) is guided by a right angle prism (5) from a direction perpendicular to the parallel light (4) so that it enters a half prism (6) at right angles. The right angle prism (
5) The collimating head (3°) is connected to the collimating head (3°).
3), and is used to simplify the configuration and facilitate adjustment.

(6) is a half prism consisting of two right-angled prisms, and a light-transmitting film is attached to the slope (7).
) splits the incident light at a constant ratio in the direction of incidence and in the direction perpendicular to the direction of incidence. The parallel light (4) enters the front surface of the half prism (6) at right angles, and the parallel light (4) enters the front surface of the half prism (6) at right angles.
) into parallel light (41) in the incident direction and parallel light (42) in the direction perpendicular to the above-mentioned direction of incidence, and the parallel light (41)
The beam radius of and (42) is equal to the major axis beam radius (43) and minor axis beam radius (48) of the parallel light (4) [see Figure 2 (d), (e), and (f)], and the half prism (6)
The splitting ratio is 1:1, and the maximum light intensity (44) of the incident light is divided at a constant ratio, and parallel light (41) and (42) are generated.
By the way, the half prism (6) preferably has a division ratio of 1:1 regardless of the polarization of the incident parallel light.
The coating film in 7) may be a metal-dielectric hybrid coating, etc., and the half prism (6) has a dimension larger than the width of the constant light intensity distribution of the synthesized light, which will be described later.
And the width of the constant light intensity distribution of the combined light is half prism (6
) within the dimensions.

In addition, the parallel light (4°) enters the side surface of the half prism (6) at right angles from the direction perpendicular to the parallel light (4), and
) into parallel beams (41') and (42''), respectively.Parallel beam (4') is divided into parallel beams (41') and (42'') by its major axis beam radius (43) and minor axis beam radius (48) with respect to parallel beam (4). The maximum intensities (44) are made equal.The laser light source (1
) is a semiconductor laser, the above beam radius (43)
In order to make them equal, select those with equal radiation angles. The maximum intensity (44") of the parallel light (41") is adjusted by the APC circuit (3o) mentioned above and made equal to the maximum light intensity (44) of the parallel light (4), so the parallel light (41
) and (42') also have a long sleeve beam radius (43) and a short axis beam radius (48), similar to the parallel beams (41) and (42), and have the same length.

The parallel lights (41) and (41') emitted in the same direction from the half prism (6) become a composite light (8). The parallel beams (4) and (4') are connected to a half prism (6) so that the optical axes of the parallel beams (41) and (41') are parallel.
The incident angle to the composite light (8) is adjusted, and the composite light (8) also has its optical axis direction (
21) becomes parallel light. In addition, parallel light (41) and (4
If the beam center (47) of 1') and the beam interval (46) of (47') are arranged approximately equal to the beam radius (43), the composite light (8) will be directed in the composite direction as shown in Figure 2 (a). (2
2), the maximum light intensity is (60) at the beam spacing (46).
), and the intensity distribution can be made constant. As mentioned above, the long sleeve beam radius (43) is set in the composite direction (
22) is advantageous because the beam spacing (46) can be widened. The short axis beam radius (48) of the parallel beams (41) and (41°) is oriented in the direction of movement (23) perpendicular to the synthesis direction (22), as shown in FIG. 2(b). has a Gaussian distribution. Then, the maximum light intensity becomes as shown in (45), and at the apex, the intensity distribution is constant within the range of the slit width (26).

In Fig. 1, (9) is a laser beam absorber, which is the parallel beam (42) and (42') emitted from the half prism (6).
) to prevent it from being scattered.

(10) is an optical head, collimating head (3) and (
3'), right angle prism (5), half prism (6),
Slits (13) and (14), sensor (16)
, filters (17) are integrated by aligning their optical axes and fixing them. The output aperture (11) of the optical head (10)
), the composite light (8) is projected onto the object to be measured (20), and the light blocked by the cross section of the object to be measured (20) is transmitted to the entrance (
The transmitted light (1) received by the slit (12) and passed through the slit (14)
5) is a measurement head that receives light with a sensor (16) and measures the projected area and outer diameter of the object to be measured (20) from the amount of received light.

The device described above can measure the outer diameter of the object by irradiating parallel laser light onto the object to be measured and receiving the transmitted light on the sensor. By keeping the light beam intensity distribution constant, the measurement range can be expanded, and measurement errors can be prevented even if the object to be measured is a wire and its position is blurred due to high-speed running.

Next, we will discuss how detection sensitivity can be increased by using slits.

The slit (13) is attached to the exit port (11) so that the composite light (8) passes through the opening with the length and width of the slit, and the scattered light and disturbance light from the object to be measured (20) are removed from the APC circuit. This prevents the light from entering the sensor (28). If the exit port (11) is made like a slit (13), the slit (13) can be omitted.

The slit (14) is connected to the entrance port (12) and the measurement sensor (
16), the transmitted light (15) passes through the opening, and prevents scattered light and disturbance light from the object to be measured (20) from entering the measurement sensor (16). The light intensity distribution of the transmitted light (15) received by 16) passes through a certain range. Inlet port (12)
If you make it like slit (14), slit (14)
Although this can be omitted, in order to reduce as much as possible the scattered light and disturbance light that leak into the sensor (16), it is desirable to arrange the entrance port and the slit separately as in the previous embodiment.

In any case, the exit port (11) and the entrance port (12) are originally a housing for internal protection and a window for passing light, but the exit port (11) is made to have the same dimensions as the slit (13). Also, if the entrance port (12) is made to have the same dimensions as the slit (14), there will be two slits each, which can prevent leakage and scattered light. 11) If the entrance port (12) is made to have the size of a slit, the sulins (13) and (14) can be omitted.

Therefore, the slit length (25
) is less than or equal to the beam spacing (46), and the slit width (26)
is sufficiently shorter than the beam radius (4 days) [Figure 2 (a)
(b)]. The beam center (47) and slit width (26) of the composite light (8) in the direction of movement of the object to be measured (23)
Align the center of the slit length (25) with the beam spacing (46
), the transmitted light (15) passing through the slit length (25) will be as shown in Figure 2 (a).
) has a constant intensity distribution, such as the maximum light intensity (60), and the transmitted light (15) passing through the slit width (26) has a Gaussian distribution near the beam center (47) as shown in Figure 2 (b). The change is small with respect to the maximum light intensity (45), and it can be regarded as the maximum light intensity (45), and the transmitted light (15) passing through Surin (14) has a constant intensity distribution.

The sensor (6) converts the amount of light received on the light receiving surface into an output current (31) proportional to the amount of light received, and outputs it.
For example, a photodiode, PIN diode, phototransistor, APD, or other light receiving element can be used. For high-speed measurements, PIN diode, AP
Use one with good responsiveness such as D.

In order to improve measurement accuracy, the sensor (16) preferably has a constant output current (31) in each part of the light receiving surface relative to the amount of light received. In FIG. 4(b), the sensor (1
The output current (31) in step 6) is converted and amplified by the preamplifier (32) to produce a voltage signal (33) proportional to the output current (31).The voltage signal (33) is measured as described above to determine the amount of light received. can be found. When the composite light (8) is projected onto the object to be measured (20) and the light blocked by the cross section of the object to be measured (20) is received by the sensor (16), the amount of light blocking of the area of the object to be measured is determined by the voltage. Change value (29) of signal (33)
By instructing the indicator (34) (see FIG. 3(d)), the amount of light shielding and the outer diameter of the object to be measured (20) can be determined.

The filter (17) shown in FIG.
It is attached to the output port (11) and the input port (12) of the laser light source (10) and blocks light other than the wavelength of the laser light source (1). ).

The object to be measured (20) is a linear object such as an electric wire, thread, wire, etc., and may move at high speed in the axial direction and may be accompanied by vibration.The object to be measured (20) is shown in each figure. The optical head (10) is arranged to move in the moving direction (23) of the optical head (10).

At this time, the measurement range that can be accurately measured by the optical head (10) is between the exit port (11) and the entrance port (12) because the combined light (8) is parallel light in the optical axis direction (21). The range is surrounded by the slit length (25) in the composite direction (22) and the slit width (26) in the direction of movement of the object to be measured (23), and the projection plane of the object to be measured (20) is the slit length (25). It only needs to be within the range of the slit width (26), and vibration of the object to be measured (20) can also be tolerated.

In FIG. 3(a), the half prism (6) is removed and parallel light (4) is used instead of the composite light (8), and the parallel light (4) is projected from the exit port (11). When measuring the outer diameter of the object to be measured (20), the slit (14)
The center of the slit width (26) is placed near the beam center (47), and the long beam radius (43) of the parallel light (4) is placed in the direction of the slit length (25).

When the object to be measured is moved in the direction of the slit length (25), the relationship between the amount of light received by the moved position sensor (16) and the change value of the voltage signal (43) is as shown in Figure 3 (b). 29). Therefore, when the object to be measured (20) is irradiated with parallel light (4), an image blocked by the object to be measured (20) is focused on the sensor (16), but at this time, the image on the sensor (16) is is the object to be measured (2
The size is equal to the light-shielding area of 0). However, the light intensity of the Gaussian distribution that is blocked changes depending on the position where the object to be measured (20) moves, and the amount of blocked transmitted light (15) is obtained by integrating the light intensity over the blocked area. Object to be measured (2
If the outer diameter of 0) is a sufficient ratio to the major axis beam radius (43), it is possible to measure the outer diameter by measuring the amount of light shielding that minimizes the amount of light received by the sensor (16). See FIG. 3(b)]. In other words, the light shielding area is the slit width (26
) and the outer diameter and the assumed slit width (26) is constant, so the light shielding area is proportional to the outer diameter. Also, the major axis beam radius (
Since the outer diameter is sufficiently small compared to 43), the beam center (4
7) The nearby Gaussian distribution has a small change with respect to the maximum light velocity intensity (44), and if it is considered to be almost constant and the maximum light intensity (44), then the amount of shading is proportional to the outer diameter and the maximum light intensity (44). [See the upper left diagram in Figure 3(a)]. Therefore, the maximum amount of light shielding is proportional to the outer diameter. This method requires measurement in a range where the Gaussian distribution is approximately constant near the beam center (47), and requires means such as positioning or scanning of the object to be measured (20).

Therefore, in Fig. 3 (C), parallel beams (4) and (4゛) are combined using a half prism (6) as described above.
8) If the object to be measured (20) is illuminated with light and the sensor (16) receives only the range of -phototactic intensity distribution of the composite light (8) in (14), the composite light (8) is ) is parallel light, the shaded image on the sensor (16) has a size equal to the shaded area of the object to be measured (20), and the opening of the slit (14) has a constant light intensity distribution. Even if the object to be measured (20) is displaced in the synthesis direction (22), the amount of blocked transmitted light (15) and the amount of light received by the sensor (16) can be kept constant.

The light shielding area is considered to be the product of the slit width (26) and the outer diameter of the object to be measured (20).Since the slit width (26) is constant, the light shielding area is proportional to the outer diameter. The amount of light blocking on the sensor (16) is obtained by integrating the light intensity distribution over the light blocking area, and since the light intensity distribution is constant, it is proportional to the light blocking area. The amount of light shielding is proportional to the outer diameter, and by measuring the amount of light shielding, the outer diameter of the object to be measured (20) can be measured. As mentioned above, the opening of the slit (14) has a constant light intensity distribution, and the object to be measured (20) is directed in the synthesis direction (22
), the measured value can be kept constant within the range of the slit length (25).

In this way, it is sufficient that the object to be measured (20) is within the range of the slit length (25) and the slit width (26), and the combined light (8) is parallel light in the optical axis direction (21). Therefore, vibrations of the object to be measured (20) in the optical axis direction (21) and in the composite direction (22) can also be tolerated.

The outer diameter of the aforementioned object to be measured (20) is the slit width (26)
However, if the slit width (26) is shortened, it may be possible to measure small changes in the outer diameter. Moreover, as mentioned above, since the composite light (8) that is projected onto the object to be measured (20) is parallel light, the sensor (1
6) The above light-shielding image has a size equal to the light-shielding area of the object to be measured (20), and the light-shielding image is clear even with a minute outer diameter, and measurement is possible even with a minute outer diameter.

In any case, sensor output = (light emission intensity distribution) x (shading area) x (sensor sensitivity distribution), and since the light emission intensity distribution and sensor sensitivity distribution are constant, the sensor output is equal to the shade area S. Proportional.

On the other hand, if the average outer diameter of the object to be measured is 1, then the slit width is given by X-(shading area S)+(slit width), so the outer diameter l is proportional to the shading area.

Therefore, the outer diameter! If the slit width is sufficiently small, the maximum and minimum can be found.

Next, when continuously measuring the outer diameter of the linear object to be measured (20) by moving it in the axial direction, the optical head (1
The object to be measured (20) is moved in the moving direction (23) of 0), but if the object to be measured (20) has a large defect (18) as shown in Figure 4 (C), the voltage signal (33) will change. The change is large, and if there is a microdefect (19), the change in the voltage signal (33) is small. At this time, the magnitude of the change in the wire diameter of the object to be measured (20) can be measured from the magnitude of the change in the voltage signal (33),
As shown in Fig. 3(b) and (d), change value (29) is measured by indicator (3).
4), the outer diameter of the object to be measured (20) can be measured, and if the voltage comparator (35) shown in Fig. 4(b) is used, a pass/fail judgment can be made for changes in diameter exceeding the set value. , voltage signal (3
3) Using the bottom holder (36) to find the maximum outer diameter (53) shown in Figure 4(e), the change value (29) is averaged with an integrator (37) to calculate the outside diameter of the average. Diameter (
54) Can be changed.

Furthermore, the magnitude of change in the axial wire diameter of the object to be measured (20) can be determined by measuring the frequency, which is the change in time (50) of the voltage signal (33). Desired. The voltage signal (33) is passed through the filter (
38), if only large changes are taken as the low frequency signal (51) and judged by the voltage comparator (35), only the large defect (18) which is large in both the axial and radial directions can be judged and the result can be changed as pass/fail.

When the object to be measured (20) described above is a thread, a number of ultrafine threads called single threads of several to tens of microns are twisted together to form a thread of several hundred microns.

In order to measure changes in the wire diameter of the yarn and the number of fuzz that protrude outside the yarn diameter when the yarn moves at high speed in the axial direction, it is necessary to measure at a high frequency on the order of megahertz. The sensor (16) of the embodiment can sufficiently respond to this speed and has a resolution sufficient to measure an extremely fine single yarn by reducing the slit width (26), and filters (38) the frequency change of the voltage signal (33). ) to separate fluff and thread diameter changes. A low frequency signal (5
Regarding 1), the maximum outer diameter (53) of the yarn can be determined using the bottom holder (36), and the average outer diameter (54) can be determined using the integrator (37). Further, the diameter of the yarn can be determined by the voltage comparator (35). A high frequency signal (52) indicating fuzz is recorded by using a differentiator (39) and a zero-cross voltage comparator (35), and counting the number of fuzz by a counter (4o) for each length of yarn at a constant pitch.

In this way, the outer diameter measuring device of this embodiment can measure the wire diameter with high resolution, measure large defects (18) and small defects (19) simultaneously, and can measure at high speed. This is an outer diameter measuring device that allows

In order to accurately measure the outer diameter of the object to be measured (20), fluctuations in the output of the laser light source (1), which cause disturbances, and the object to be measured (20)
This reduces the amount of scattered light and disturbance light caused by the sensor (16), increases the accuracy of the amount of light received by the sensor (16), reduces noise in the measurement circuit including the sensor (16), and increases the accuracy of the measured value. For this purpose, a filter (17) and a slit (13) are attached to the exit port (11) of the optical head (10), and the entrance port (12) is provided with a filter (17) and a slit (13).
) Attach the filter (17) and slit (14).

In this way, scattered light and disturbance light from the object to be measured (8) are transmitted to the sensor (28) of the APC circuit and the measurement sensor (1).
6), so as to prevent output fluctuations of the laser light source (1) and improve the accuracy of measured values.

In any case, according to the above method, it is possible to measure the time change of transmitted light of a moving object to be measured, separate its frequency, and simultaneously measure the diameter value and minute defect.

The half prism (6) may be a polarizing beam splitter (56) as a means of creating the composite light (8), and the polarizing beam splitter (56) transmits the incident light when the polarization direction is perpendicular to the slope (57) and does not reflect it. , which reflects when it is horizontal and does not transmit, and can be made by pasting together right-angle prisms.

In Fig. 5, the laser light sources (1), (1”) are He
- When emitting parallel light (4), (4゛) with random polarization and a circular beam cross section, such as a Ne laser, the parallel light (41) emitted from the polarizing beam splitter (56),
The polarization directions of (41') are orthogonal to each other, and the parallel light (41') is perpendicular to each other.
The polarization direction (58) of 1) becomes the polarization direction (59') of the parallel light (41'). At this time, the polarization beam splitter (
56) The ratio of reflection and transmission to the polarization direction is equal,
And if the beam radius and output of the laser light sources (1) and (1゛) are equal, the combined light (8) will pass through the half prism (6).
), it is possible to obtain a uniform intensity distribution in the same way as when combining the parallel light (42) and the polarization direction (58') of the parallel light (42).
Although the polarization direction (59) is 2''), the combined light (8°) can also be combined in the same way as the combined light (8).

In Figure 6, when the laser light sources (1), (1'') are linearly polarized elliptical beams like semiconductor lasers, parallel beams (4), (4'') are generated as shown in Figure 6(b). The polarization direction is 45 on the slope (57) of the polarizing beam splitter (56).
Parallel light (41) that enters at an angle of 1 and exits (41°
) so that the major axis of the beam is in the same direction. Parallel light (
4) and (4'') pass through the slope (57) and are reflected at a ratio of 1:1, resulting in composite light (8) and (8'') with a uniform intensity distribution. At this time, since the direction (22) of combining the combined light beams (8) and (8°) is inclined at about 45°, the moving direction (22) of the object to be measured (20) (
23) is arranged so that it is perpendicular to the composite direction (22).

If the object to be measured (20) is large and the measurement range is wide (if
In particular, it is necessary to increase the measurable range in the composite direction (22). In this case, as shown in FIGS. 7, 8, and 9, the measurement range can be expanded by increasing the width of the -electric light intensity distribution of the combined lights (8) and (8').

To explain Fig. 7, (55) is a prism bear that expands the beam diameter of the incident light in one direction, and the beam diameter of the incident light is expanded only in the direction where there is a difference in prism thickness. The beam diameters are the same in each direction, and if the incident light is parallel light, the output light will also be parallel light. 2
The optical axis of parallel light magnified on the input side of the prism bends in the expansion direction, but if the prism on the output side is properly arranged, it will also be expanded on the output side and the optical axis of the input light and the output light will be The optical axes are parallel, and in the direction where the prism thickness is equal, the optical axes are in a straight line.

The above parallel beams (4) and (4゛) are connected to the prism bear (55).
, (55') and is arranged so as to expand the major diameter beam radius, the major diameter boom radius of the output beam is expanded and parallel light (
4a) and (4a'). The half prism mentioned above (
By combining the expanded long beam radii of the parallel beams (4a) and (4a') in step 6), the width of the -electrical light intensity distribution of the combined beam (8) can be expanded, and the measurement range can be expanded. The magnification rate of the prism bear (55) is 2 to 6 times, which is more advantageous in terms of utilization of optical output and miniaturization than means for expanding the beam radius using large collimator lenses or beam expanders.

Fig. 8 is an example in which three collimating heads are used to combine parallel lights (4), (4゛), and (4'') to expand the measurement range. Lights (4) and (4゛) are combined with a half prism (6゛) (
8).

Next, the combined light (8) and the parallel light (4") are combined using a half prism (6"). At this time, the beam radius of the parallel light (4") is the same as the parallel light (4), (4゛), and the output is parallel light (41) constituting the composite light (8),
(41') and adjust the incident position and angle to the half prism (6') to make the composite light (8a) and composite light (
8a') is composed of three parallel beams (4), (4゛), (4''), and - the width of the lightning intensity distribution can be expanded twice.

To explain Fig. 9, two half prisms (6
), (6゛) and two right angle prisms (5) (5) are used to expand the measurement range three times. Parallel light (4)
, (4°) are synthesized using a half prism (6) to produce composite light (
8) and (8°), and the combined light (8') is deflected by a right angle prism (5) (5) to form a half prism (6").
), the composite light (8) is guided to a surface adjacent to the half prism (6゛) and orthogonal to the composite light (8a') described later, and is combined at the slope (7゛) to produce composite light (8a). and (8a'
). At this time, if the beam radius, optical axis, and output of the combined lights (8) and (8゛) are adjusted as described above,
- The width of the lightning intensity distribution can be expanded three times.

As described above, by combining two or more parallel lights and making the light intensity distribution of the projected light constant, the measurement range can be expanded.

Next, let's look at the first example when measuring a large object to be measured.
This will be explained based on Figure 0.

Figure 10 shows a case where the outer diameter of a wide object to be measured is being measured at high speed and with high accuracy while vibrating and moving at high speed.
Parallel beams (4) and (4'') are combined into composite beams (8) and (8') by a half prism (6).

The composite light (8゛) is deflected by a right angle prism (5) to be parallel to the composite light (8), and the composite beams (8) and (8゛) are respectively projected onto both edges of the object to be measured (20). and place it within the measurement range. Align the optical axis with the composite light (8), (8゛) and connect the slits (14), (14') and sensor (1).
6), (16”) and slits (14), (14
”) using a method such as a micrometer.

Voltage signals (33), (
33") using the adder (65), the measured object (2
0), and by adding the distance between the slits (14) and (14') to that value, the dimension between both edges can be measured, and the object to be measured (20)
The vibrations are canceled out by the adder (65) and have no effect.

In addition, using two optical heads (10) and (10'), the combined light (8) is applied to the edge of the object to be measured (20) as described above.
, (8") may be emitted and measured.

FIG. 11 shows an embodiment used when the object to be measured (20) has more parts to be measured.

A large number of composite lights can be created by dividing the composite light using half prisms (6), (6゛), and (6'').The composite light (8) is split by dividing the composite light using half prisms (6), (6゛), and (6''). ”), resulting in composite light (8a) and (8b), and composite light (
8a) is deflected by the right-angle prism (5). The 0 composite light (8゛) is guided by the right-angle prism (5) to the half prism (6"), and is divided by the slope (7") to become the composite light (8c) and (8d). )
The combined light (8d) is deflected by the right angle prism (5). Combined light (8a), (8b) 1, combined light (8c), (
8d) are slits (14a) and (14b) arranged so that they are parallel and whose optical axes are aligned with each other when the light is projected onto the object to be measured (20).
, (14c), (14d), sensor (16a), (1
6b), (16c), and (16d) and measurement is performed. When the object to be measured (20) has several holes or grooves, it is possible to measure the diameters of the holes or grooves at the same time.

(Effects of the Invention) The outer diameter measuring device according to the present invention measures the area and outer diameter of the object by irradiating the object with parallel laser light and receiving the transmitted light with a sensor. I can do it.

By limiting the measurement range with a means to give a constant intensity distribution of the laser beam and a slit, positional deviation and vibration of the object to be measured can be tolerated, and even extremely fine wire diameters can be measured.

In addition, the high-speed response of the sensor makes it possible to measure minute changes in objects to be measured that are moving at high speed, and by means of frequency discrimination of the sensor output signal, it is possible to simultaneously measure minute changes and large changes in the outer diameter of objects to be measured. can.

Furthermore, not only can the measuring range be expanded by the beam radius enlarging means, but also a wide object to be measured can be measured by controlling the light projection operation to the edge of the object to be measured.

[Brief explanation of drawings]

Figures 1 (a) and (b) are a plan view and a front view of the first embodiment, Figures 2 (a) and (b) are a plane view and a front view of the combined light, and the same figure (
C) is an explanatory diagram showing the incident state of parallel light to the half prism (6) of the same figure (a), and (d), (e), and (f) are explanatory diagrams showing the light intensity distribution of each parallel light, Figures 3 (a) and 3 (b) are graphs of the light intensity distribution and its detection signal when parallel light is used to irradiate the object to be measured, respectively, and Figure 3 (c) and (d) are graphs when combined light is used. An explanatory diagram of the light intensity distribution and a graph of its detection signal when Figure, (ii) (
if) is a light intensity distribution map of the major axis beam radius and the minor axis beam radius, respectively. ] Figures 44a to 44(f) are block diagrams of the detection circuit and explanatory diagrams of detection signals, and Figures 5(a) and 44(b) are plan and side views of the second embodiment using a polarizing beam splitter. , Figures 6(a) and (b) are plan and side views of the third embodiment using a polarizing beam splitter, and Figures 7(a) and (b) are the fourth embodiment in which the combined light is expanded using a prism pair. Fig. 8 is a plan view of the fifth embodiment in which the combined light is expanded by three parallel beams, and Fig. 9 is a plan view of the sixth embodiment in which the combined light is expanded by two prism pairs. A plan view, FIG. 10 is an explanatory diagram of the seventh embodiment, and FIG. 11 is an explanatory diagram of the eighth embodiment. (1)...Laser light source (2)...Collimating lens (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (1 day) (19) (20) (21) (22) ...Collimating head...Parallel light...Right angle prism...Half Prism... Slope... Combined light... Absorber... Optical head... Output port... Inlet port... Slint... Slint... Transmitted light... Sensor... Filter...Minute defect...Large defect...Object to be measured...Optical axis direction...Composition direction (23) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43) ・Moving direction, slit length, slit width, measurement Range, sensor, change value, APC circuit, output current, preamplifier, voltage signal, indicator, voltage comparator, bottom holder, integrator, filter, differentiator, counter, parallel light, parallel light, long axis beam radius (44 ) (45) (46) (47) (48) (49) (50) (51) (52) (53) (54) (55) (56) (57) (58) (59) ・Maximum strength・Maximum intensity, beam spacing, beam center, short axis beam radius, voltage value, time, low frequency signal, high frequency signal, maximum outer diameter, average outer diameter, prism pair, polarizing beam splitter, slope, polarization direction, polarization direction 49 Voltage Values Figure 4 Figure 5 (a) (b) Figure (a) (b) 8" 47-

Claims (3)

[Claims] (1) When measuring the outer diameter by irradiating a linear object to be measured running at high speed with a laser beam that is a parallel beam with a constant cross-sectional outline and detecting the amount of light blocked by the object, multiple beams are used. An outer diameter measuring device characterized by making the light intensity distribution within a beam cross section constant by combining the beams. (2) A claim characterized in that a slit is arranged in the front part of the sensor to increase detection sensitivity and make it possible to measure extremely fine wire diameters (
The outer diameter measuring device according to 1). (3) The method according to claim (1) or (2), characterized in that the time change of the transmitted light of the moving object to be measured is measured, its frequency is separated, and the diameter value and minute defect are simultaneously measured. Outer diameter measuring device. (4) A claim characterized in that a wide object is measured by measuring the edge of the object to be measured using two light emitting sensors, and measuring the values of the two light receiving sensors and the distance between the two light receiving sensors. The outer diameter measuring device according to item (1) or (2).