JPH0758178B2 - Ultrasonic seam detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention is a non-measurement object in which an ultrasonic wave transmitter and a wave receiver are opposed to each other, and an object to be measured is arranged in a non-contact manner between the two. Position, thickness,
The present invention relates to an ultrasonic wave detector for measuring a seam, etc., and particularly to an ultrasonic wave seam detector that reduces interference with a reflected wave from a wave transmitter, a wave receiver, an object to be measured, or an object around them.

[Conventional technology]

For example, light is emitted to detect the end position of the web (strip-shaped object), and the end position is detected by the amount of light shielding. Air is used in the case of an object that transmits light or an object that is photosensitive. In addition, the ultrasonic transmitter and the ultrasonic receiver are arranged to face each other, the web is arranged between them, and the position of the end of the web is determined by the amount by which the ultrasonic waves emitted continuously are blocked by the web. A detecting device is disclosed in Japanese Patent Laid-Open No. 63-117865.

Various measures for noise prevention are known for a technique of measuring an ultrasonic transmitter or a receiver in close contact with an object to be measured or a technique of measuring a reflected wave to measure a level or a position. For example, sensor technology Vol.5 No.15
(December 1985) Page 56, Sensor Technology Vol.8.No.9 (1988
(August, 2010) On page 50, a technology for intermittently transmitting a signal to prevent the noise of reflected waves is disclosed, but the technology for using the transmitter and receiver in a contactless manner is new. There was no technology to prevent noise, and it was a big bottleneck.

Next, taking the detection of the seam of the web as the measured object as an example,
The seams of the web are connected by a seam tape or the like, and the seam part is thicker than the normal part. Therefore, the seam portion can be detected by detecting a position thicker than the normal portion.

It should be noted that commonly used web materials include paper, cellophane, aluminum foil, polylaminate, and the like, and seam tape materials include paper, vinyl, aluminum foil, and the like. The material of the web and the seam tape do not necessarily have to be the same. By the way, the seam detector is attached to various machines such as a rotary printing press, a laminator, and a slitter. Among them, in the offset rotary printing press, since the bracket is damaged when the web thickness increases at the joint, the impression cylinder is allowed to escape at the joint to avoid this. Also, in rotary printing presses, laminators, slitter machines, etc., if the seam part is mixed into the final product, it will cause a problem in quality control. Processing such as attaching is performed.

As a seam detection method that has been conventionally used, a mechanical contactor is applied to the object to be measured, a contact type that detects the seam by the displacement of the contactor, emits visible light or infrared light, and is measured from the object to be measured. There is a non-contact type photoelectric system that detects a seam by a change in the amount of transmitted light or a reflected light amount, and a non-contact capacitance type that detects a seam by detecting a change in capacitance of a thickness change portion.

[Problems to be Solved by the Invention]

Among the above-mentioned conventional techniques, when detecting the edge position of the web by using air, the quality of the web may be deteriorated due to the cleanliness of the air or the inclusion of dust in the surroundings. The edges of the web may wavy or get caught. Ultrasonic detectors have also been commercialized, but they are easily affected by ambient temperature and wind, and when the web undulates, the output signal may change and lack stability.

The reason for this is presumed as follows.

The ultrasonic wave is continuously emitted from the ultrasonic wave transmitter to the ultrasonic wave receiver facing it, but the reflected wave reflected by the ultrasonic wave receiver interferes with the direct wave from the ultrasonic wave receiver. Generate a standing wave. This standing wave also enters the ultrasonic wave receiver, but the standing wave changes when the ambient temperature changes, because the wavelength changes due to the change in the sound velocity in the air. Therefore, the output signal of the ultrasonic receiver changes.

Further, when a part of the ultrasonic wave passing between the ultrasonic wave transmitter and the ultrasonic wave receiver is blocked by the web, the ultrasonic wave hitting the web is reflected by the web surface. This reflected wave interferes with the direct wave from the ultrasonic transmitter to generate a standing wave. When the web fluctuates in a direction perpendicular to the traveling direction, that is, when the pass line fluctuates, the phase of the reflected wave from the web with respect to the direct wave changes, so that the standing wave also changes. For this reason, when the web hits a wave or the pass line fluctuates, the standing wave changes and the output signal of the ultrasonic receiver fluctuates and becomes unstable.

Further, in the case of detecting the seam portion by the contact method, particularly when the object to be measured is thin, mechanical high accuracy is required for the contact portion, and when the object to be measured is soft, it is difficult to detect the seam. Further, in the case of the photoelectric type, it cannot be used when the object to be measured has a pattern, a transparent film, or a light-shielding property. In case of capacitance type, it cannot be used when the object to be measured is aluminum foil. In addition, there may be restrictions on the color and material of the seam tape used.

In addition, if there are other objects around the ultrasonic transmitter, ultrasonic receiver, or DUT, the ultrasonic waves emitted from the ultrasonic transmitter are reflected by surrounding objects, and the reflected waves are received. It interferes with the ultrasonic waves that have reached the wave device and have come directly from the wave transmitter, and the ultrasonic waves that have passed through the object to be measured, and adversely affect the measured values of the wave receiver.

An object of the present invention is to provide an ultrasonic wave transmitter, an ultrasonic wave receiver, an object to be measured, and an ultrasonic seam detector in which interference with reflected waves from these surrounding objects is reduced.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, an ultrasonic wave transmitter for transmitting an ultrasonic wave and an ultrasonic wave transmitter are disposed so as to face the ultrasonic wave transmitter, and the distance between these ultrasonic wave transmitters is relative to the ultrasonic wave transmitter. An ultrasonic wave receiver that receives the ultrasonic wave that has passed through the moving object to be measured, and a wall that reflects ultrasonic waves around the ultrasonic wave transmitter and the ultrasonic wave receiver. In the arranged ultrasonic seam detector, the directivity or directivity of the ultrasonic wave provided on at least one of the transmitting surface of the ultrasonic transmitter and the receiving surface of the ultrasonic receiver is sharpened. A horn, and a seam detector that detects the seam by comparing the received wave of the normal part and the received wave of the seam of the measured object received by the ultrasonic wave receiver with a predetermined reference value. And a detection unit for detecting the signal according to the magnitude of the transmitted reception by detecting the output of the ultrasonic receiver by the seam detection unit. A peak hold circuit for holding the peak value of the output of the detection unit, a reference value generation circuit for generating the predetermined reference value from the peak value held by the peak hold circuit, an output of the reference value generation circuit and the A comparison circuit that compares the output of the detection unit and a seam detection signal based on the output of the comparison circuit, and each time the seam detection signal is output, the peak hold circuit is reset during the output time of the seam detection signal. And an output circuit.

[Work]

In the ultrasonic detector in which the wave-transmitting surface of the ultrasonic wave transmitter and the wave-receiving surface of the ultrasonic wave receiver are arranged to face each other, and the DUT is arranged in a non-contact manner between them, the directivity of the ultrasonic wave is set on the wave-transmitting surface. If the sharpening horn is provided and the ultrasonic waves are concentrated on the receiving surface, the receiving performance of the ultrasonic receiver is improved. Further, if a horn for sharpening the directivity of ultrasonic waves is provided on the wave receiving surface to narrow the receiving range, the wave receiving performance of the ultrasonic wave receiver is improved. In particular, when there is an object around the ultrasonic detector and the object to be measured, the ultrasonic wave reflected by the surrounding object is incident on the receiving surface, and the reflected ultrasonic wave and the ultrasonic wave necessary for detection interfere with each other. Therefore, the reception performance of the ultrasonic receiver is degraded, but the effect of reflected waves is reduced by installing the horn on either or both of the transmitting surface and the receiving surface to reduce the receiving performance of the ultrasonic receiver. Improve.

Further, the seam portion of the measured object is thicker than the normal portion. Therefore, the amount of transmission that is transmitted to the ultrasonic wave receiver through the DUT that moves between the ultrasonic wave transmitter and the ultrasonic wave receiver that are disposed opposite to each other is usually the seam. Less than the department. The seam can be detected by comparing the amount of decrease with a predetermined reference value and detecting it.

As a seam detector, the detector detects a signal from the output of the ultrasonic receiver according to the magnitude of the transmitted wave, and the peak hold circuit holds the peak value of the detector for the time constant of the peak hold circuit. Then, the reference value generation circuit generates a reference value based on the peak value held by the peak hold circuit, and the comparison circuit compares the reference value with the output of the detector and sets the signal above the reference value as the normal part of the DUT. Signals below the standard are discriminated from the joint of the DUT.

Each time the output circuit outputs the seam detection signal, the peak hold circuit is reset for the output time of the seam detection signal, so that the peak hold circuit holds a new value each time the seam passes, and the reference value is generated. The circuit sets a new reference value based on this new value. As a result, even when the objects to be measured having different thicknesses are spliced at the seam portion with the seam tape, the reference value is automatically set based on the thickness of each object to be measured.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

FIG. 1 is an explanatory view showing web position detection as the first embodiment.

The ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3 are arranged so as to face each other to form an ultrasonic wave detector.
And the wave receiver 3 are installed separately from each other.

Horns 2 and 4 are attached to the harmonic wave transmitter 1 and the ultrasonic wave receiver 3, respectively. The ultrasonic detector and the DUT 5 are surrounded by a surrounding object 6. The DUT 5 may be completely on the wave-transmitting surface of the ultrasonic wave transmitter 1, may be partially, or may not be on the wave-transmitting surface at all. Since the horn 2 for sharpening the directivity of the ultrasonic waves is attached to the wave transmitter 1, the ultrasonic waves are emitted as a narrow beam toward the wave receiver 3. Further, the wave receiver 3 is also provided with the horn 4, which limits the detection of only the incident ultrasonic waves, thereby improving the wave receiving ability. Further, even if the surroundings are surrounded by the surrounding object 6, an ultrasonic wave having a good directivity is emitted from the horn 2 of the transmitter 1, so that a small amount of the ultrasonic waves hit the surrounding object 6 and are reflected, and the reflected ultrasonic waves are received in the incident direction. Since it is limited by the horn 4 of the wave device 3, the influence of the surrounding object 6 can be reduced.

FIG. 1 (a) shows an ultrasonic detector and a web 5 to be measured.
And FIG. 1 (b) is a diagram showing a relative position with respect to FIG.
FIG.

The ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3 are arranged to face each other, and the wave-transmitting surface and the wave-receiving surface are arranged in parallel. The web 5 is obliquely viewed at a predetermined angle with respect to the wave transmission surface. Horns 2 and 4 are attached to the ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3, respectively. The direct wave transmitted from the ultrasonic wave transmitter 1 is directly reflected by the facing surface of the web 5, but since this reflected wave does not interfere with the direct wave from the wave transmitting surface, the generation of a standing wave can be prevented. In this way, the position of the DUT 5 can be measured in an analog manner by the reception intensity of the wave receiver 3 as shown in FIG.

Next, web position detection will be described as a second embodiment with reference to FIGS.

In the second embodiment, the directivity and receptivity of ultrasonic waves are improved by a horn, and the ultrasonic waves are intermittently transmitted, and the ultrasonic waves propagate between the transmitter and the receiver for the duration of the transmission. The influence of the standing wave generated by the interference is removed by setting the transmission wave cutoff period to be longer than the time period in which the interference of the reflected wave is attenuated to a predetermined value or less. FIG. 2 is a block diagram of the second embodiment, FIG. 3 is a time chart of FIG. 2, and FIG. 4 is a diagram showing the effect of this embodiment.

In FIG. 2, 1 is an ultrasonic wave transmitter, 2 is a horn for improving directivity, 3 is an ultrasonic wave receiver, and 4 is a horn for improving directivity. The sound wave receiver 3 is arranged so as to face it, and the wave transmitter 1 and the wave receiver 2 are arranged in parallel. Reference numeral 5 denotes a web, which is arranged in the middle of the ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3 and partially blocks the direct wave from the ultrasonic wave transmitter 1 to make the ultrasonic wave receiver 3 Then, the detection information of the position of the web 5 is obtained from the cutoff amount. An oscillating circuit 11 generates an oscillating signal A of ultrasonic waves transmitted by the ultrasonic wave transmitter 1. A timing circuit 12 generates a timing signal for controlling this device. A power amplifier circuit 13 amplifies the oscillation signal A oscillated by the oscillation circuit 11 to generate a drive signal E of a required magnitude for the ultrasonic wave transmitter 1 to generate an ultrasonic wave. 14 is an AND circuit, and oscillation circuit 1
The period in which the oscillation signal A is transmitted to the power amplifier circuit 13 from 1 is controlled by the timing signal B from the timing circuit 12. A pre-amplifier circuit 15 amplifies the position information F of the web 5 received by the ultrasonic wave receiver 3. Reference numeral 16 is a peak hold circuit which holds the peak value of the position information F of the web 5 and outputs the hold value G. When the timing signal B of the timing circuit 12 rises, the previous hold value is cleared and the timing signal The operation is started by the rise of C. A sample and hold circuit 17 holds the hold value G at the rising edge of the timing signal D of the timing circuit 12 and outputs it as a signal H. An output circuit 18 outputs the signal H as a predetermined level. Next, the operation will be described with reference to FIG.

The oscillating signal A from the oscillating circuit 11 is supplied to the power amplifying circuit 13 only during the period of the timing signal B and is amplified into the drive signal E, and the ultrasonic wave is transmitted from the ultrasonic wave transmitter 1 during the generation period of the drive signal E. This ultrasonic wave transmission period, that is, the period in which the timing signal B is output, is set to a time shorter than the time it takes for the ultrasonic waves to propagate the distance between the ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3. Therefore, the position information signal F of the web 5 is generated in the ultrasonic wave receiver 3 after the ultrasonic wave E'generation period (drive signal E generation period) ends. The peak value of the information signal F is held as G, and the sample hold value H is obtained by the rising of the timing signal D. The rising timing of the timing signal D is a timing before the position information signal F interferes with the reflected wave, and thus the position information F becomes data in a state where a standing wave due to the reflected wave is not generated. Further, the timing signal B is restarted when the adverse effect of the reflected wave or the like disappears.

The effect of intermittently emitting ultrasonic waves under the above conditions will be described with reference to FIG.

When the ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3 are arranged so as to face each other and the ultrasonic waves are continuously emitted, the direct wave and the reflected wave interfere with each other to generate a standing wave, and the ambient temperature is influenced by the standing wave. The signal H of the sample and hold circuit 17 is the fourth
It changes greatly as shown in FIG. However, if ultrasonic waves are emitted intermittently under the conditions of this embodiment, a standing wave is not generated, and the signal H of the sample hold circuit 17 is gentle even if the ambient temperature changes as shown in FIG. 4 (b). A stable and stable output signal can be obtained.

Also, by attaching the horns 2 and 4, the directivity and receptivity of ultrasonic waves are improved, and the reflection from surrounding objects is eliminated, so the wave receiving capability of the ultrasonic wave receiver 3 is improved and a stable output signal is generated. To do.

Next, a third embodiment will be described with reference to FIGS.

The third embodiment is an apparatus for detecting the change in the thickness of the object to be measured and detecting the joint portion.

FIG. 5 is a block diagram showing the configuration of the third embodiment.
Reference numeral 1 is an ultrasonic wave transmitter, and 2 is a horn for sharpening the directivity of ultrasonic waves, which is attached to the wave transmission surface of the ultrasonic wave transmitter 1. Three
Is an ultrasonic wave receiver, and 4 is a horn that sharpens the directivity of incident ultrasonic waves, and is attached to the wave receiving surface of the ultrasonic wave receiver 3. Reference numeral 5 is an object to be measured, 6 is an ultrasonic wave transmitter 1, an ultrasonic wave receiver 3, a surrounding object provided around the object to be measured 5, 21 is an oscillation circuit for oscillating a square wave, and 22 is an oscillation circuit 21. Is an electric power amplifier circuit for amplifying the output of the electric power. The ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3 are arranged to be inclined with respect to the DUT 5. Reference numeral 23 is a preamplifier circuit that amplifies the output of the ultrasonic wave receiver, 24 is a detection circuit that detects a signal indicating the thickness of the DUT 5 by the output of the preamplifier circuit 23, and 25 is an output of the detection circuit 24. A low pass filter circuit for smoothing, 26a is a peak hold circuit for the output of the low pass filter circuit 25, and 27 is a peak hold circuit 26.
A sensitivity adjuster that adjusts the value of the reference value generated from the output value of a. 28 is the sensitivity adjuster 27 that outputs the output of the low-pass filter circuit 25.
The comparison circuit for comparing with the reference value generated by, 29 is the comparison circuit 28
Is an output circuit that outputs the output of the.

Next, the operation will be described with reference to FIG.

The symbols (J to S) on the left side of the waveforms in FIG. 6 are J to S in FIG.
Corresponding to the position of S, each waveform shows the output waveform at the corresponding position.

The square wave J oscillated by the oscillator circuit 21 is power-amplified by the power amplifier circuit 22 and applied to the ultrasonic wave transmitter 1 as a square wave K.
An ultrasonic wave is emitted from the ultrasonic wave transmitter 1 by the square wave K, most of the ultrasonic wave is reflected by the surface of the DUT 5 due to the directivity of the horn 2, and the rest is transmitted through the DUT 5 and the horn 4 After being limited by, the wave receiving surface of the ultrasonic wave receiver 3 receives a part of the wave and reflects the other. Further, due to the directivity of the horn 2, the ultrasonic wave emitted to the surrounding object 6 is small, and the emitted and reflected ultrasonic wave is hardly incident on the ultrasonic wave receiver 3 due to the directivity of the horn 4. The output of the ultrasonic wave receiver 3 is indicated by L. The normal part of the DUT 5 has a constant amplitude strength, but the seam part has a reduced amplitude. The output L of the ultrasonic wave receiver 3 is amplified by the preamplifier 23 and becomes the output M. Since the positive and negative values of the output M are symmetrical about the reference axis,
The detection circuit 24 inverts the amplitude on the negative side to the positive side and outputs the signal N on the positive side. When the output N of the detection circuit 24 is smoothed through the low-pass filter circuit 25, the waveform shown by P is obtained,
A high signal is obtained at the normal portion of the DUT 5, and a low signal is obtained at the joint portion. This is because the normal portion has a large amount of transmitted and received waves, and the joint portion has a large thickness, so that the amount of transmitted and received waves is small. Signal P
The peak value of is held by the peak hold circuit 26a for the time of its time constant, and its waveform becomes Q. The sensitivity adjuster 27 generates a reference value R from the hold value Q. Comparison circuit
Reference numeral 28 discriminates based on the reference value R whether the signal P is above or below the reference value R. In the normal part of the DUT 5, P is R
P is smaller than R in the seam. Therefore, as shown by the waveform S, when the normal portion is changed to the joint portion, and when the joint portion is changed to the normal portion, the waveform of S is changed, so that the joint portion can be detected.

Thus, the reference value R of the comparison circuit 28 is the peak hold circuit.
It is generated from the output Q of 26a, and the value of this Q changes according to the signal value in the normal section and does not take a fixed constant value. Since the signal value of the normal part is always the reference, when it decreases the signal value, it is determined to be a seam. By updating the reference value, that is, the peak hold value each time the thickness of the DUT 5 changes, the reference value for the normal part of the DUT 5 is always determined.
It is not necessary to manually adjust the seam judgment reference value even if the thickness or material of the seam changes.

Next, a fourth embodiment will be described with reference to FIGS. 7th
The drawing shows a block diagram of the fourth embodiment, and the same reference numerals in FIG. 5 represent the same contents. The present embodiment is an apparatus for automatically generating a reference value according to the thickness of a measured object when the measured objects having different thicknesses are spliced with a seam tape. The difference from the third embodiment is a peak hold circuit 26b and an output circuit 29b, and the output circuit 29b outputs a joint detection signal and a reset signal to the peak hold circuit 26b. The operation will be described with reference to FIG. The object to be measured 5 is composed of an object to be measured 5a and an object to be measured 5b having different thicknesses, which are connected by a seam tape. The signals J'-P 'are the same as the signals J-P shown in FIG. 6 except that the signals 5a, 5b to be measured have different thicknesses. The peak value of the output P'of the low-pass filter circuit 25 is held by the peak hold circuit 26b for the time constant, and its output waveform becomes the value indicated by a of Q '. The sensitivity adjuster 27 generates a reference value c from the hold value a. The value of c is the sensitivity adjuster
Since it can be freely set within the range of a ≧ c ≧ o by adjusting with 27, if it is set to a value close to a, for example, even a slight change in the thickness of the DUT 5 can detect the seam. This is effective when a thin seam tape is attached to the object 5. However, in this case, the value of P'is 5
Since it also changes due to waviness, there is a case where an erroneous operation of outputting a seam detection signal although it is not a seam may occur. Therefore, in consideration of these, c is set to an appropriate value. When a thin seam tape is attached to the thin object to be measured 5, even if the value of c is set low to some extent, P'of the seam part
Is greatly reduced, so seam detection is possible. Thus, the sensitivity adjuster 27 sets the reference value c in consideration of the relative thickness relationship between the DUT 5 and the seam tape. The comparator circuit 28 discriminates whether or not the signal P'exceeds the reference value c on the basis of the reference value c, and when the magnitude relation between the signal P'and the reference value c is reversed, the signal S'at the points e and f, respectively. Invert.
When the output circuit 29b receives the inverted signal S ', it outputs the joint detection signal T for a certain period of time to notify the outside that the joint has been detected. Further, simultaneously with the output of the joint detection signal T, a reset signal is output to the peak hold circuit 26b, and the peak hold circuit 26b is reset during the output time of the joint detection signal T. This output time is set so as to be the time when the detection position moves from the measured object 5a to the measured object 5b. With this setting, the peak hold value a determined based on the DUT 5a becomes the peak hold value b determined based on the DUT 5b, and the reference value c corresponding to a also corresponds to b. It becomes a new reference value d.

As described above, according to this embodiment, even when the DUTs 5 having different thicknesses are spliced with the seam tape, the reference value corresponding to the thickness of each DUT 5 is automatically set and the seam is automatically set. The detection can be performed accurately.

Next, the ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3 are connected to the DUT 5.
The operation and effect in the case of arranging them with an inclination will be described.

If there is no inclination and it is vertical, the ultrasonic wave transmitted from the ultrasonic wave transmitter 1 interferes with the ultrasonic wave reflected from the DUT 5, and the ultrasonic wave transmitted through the DUT 5 and the ultrasonic wave The reflected wave interferes with the wave receiving surface of the acoustic wave receiver 3. When the object to be measured 5 is displaced in the thickness direction due to such interference, the distances to the ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3 change, and the direct wave and the reflected wave of the ultrasonic wave mutually strengthen each other. They weaken each other. As a result, the output of the ultrasonic wave receiver 3 largely changes, and stable detection cannot be performed. Therefore,
With the inclination, as shown in FIGS. 5 and 7, the reflected wave and the direct wave have different paths, so that such interference does not occur and stable detection is possible.

Next, the effect of the horn will be described with reference to FIG.

As shown in FIGS. 5 and 7, the sound wave transmitter 1, the horn 2, the ultrasonic wave receiver 3, the horn 4, and the DUT 5 are surrounded by the surrounding object 6. For the ultrasonic wave transmitter 1 and the ultrasonic wave detector 3 including the ultrasonic wave receiver 3, the ultrasonic wave is reflected when the surrounding object 6 is in the vicinity, which is not desirable in measurement, but the ultrasonic wave detector is installed in an actual device. When mounted, there are often many ultrasonic reflectors around. Therefore, in this example, the measurement was performed with the surrounding object 6 provided around the ultrasonic detector. About one object to be measured, two cases in which these are overlapped, a case where the horn is attached to both the ultrasonic wave transmitter 1 and the ultrasonic wave receiver 3, and a case where it is not attached to both It was measured. The results are shown in FIG. FIG. 9A shows the shape of the horn used. (B) is the case where one measured object is used without a horn, and (c) is the case where two measured objects are used without a horn. (D) is the case where one measured object is provided with a horn, and (e) is the case where two measured objects are provided with a horn. (B) to (e) show changes in the output when the DUT 5 is moved along the direction perpendicular to the traveling direction thereof, that is, the x direction shown in FIG. The large output portion at both ends of each figure is the output signal of the portion without the DUT 5, and the central small output portion is the output signal of the portion with the DUT 5. As is clear from the above, when there is a surrounding object (eg, wall, floor, etc.) close to the ultrasonic detector, if there is no horn, it will be affected by reflected ultrasonic waves from it, (b),
As shown in (c), even if the number of objects to be measured changes, there is almost no difference in the detection output, making it impossible to determine the number of objects. By attaching the horn, as shown in (d) and (e), the change in the number of objects to be measured clearly appears in the detection output, and therefore the number of objects can be determined. Even when the thickness of the object to be measured changes, if there is no horn, the difference in the detected output hardly appears, but by attaching the horn, the difference in the detected output appears and the thickness can be detected. In addition, by attaching a horn, the sound pressure and sensitivity on the wave-transmitting axis and the wave-receiving axis are improved, so that relatively external noise (ultrasonic waves from ultrasonic sources other than those directly emitted from the transmitter) S / N
There is also an advantage that is improved. The horn shown in (a) is 1
The longer the angle is and the larger the angle is, the sharper the directivity is obtained, but the shape of the horn becomes large, which causes a problem in practical use. In the case of this embodiment, 1 = 25 mm and θ = 10 °.

〔The invention's effect〕

According to the present invention, at least one of the ultrasonic wave transmitter and the ultrasonic wave receiver is provided with a horn, and the surface facing the object to be measured is inclined with respect to the ultrasonic wave transmitter and the ultrasonic wave receiver. By eliminating the interference of ultrasonic waves by generating ultrasonic waves intermittently under predetermined conditions, etc., the occurrence of standing waves is prevented,
The position, thickness, seam, overlay, etc. of the object to be measured can be accurately measured without contact.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle of the first embodiment, FIG. 2 is a block diagram of the second embodiment, FIG. 3 is a timing chart diagram of FIG. 2, and FIG. 4 is an effect of the second embodiment. FIG. 5, FIG. 5 is a block diagram showing the configuration of the third embodiment, FIG. 6 is a diagram showing the time chart of FIG. 5, FIG. 7 is a block diagram showing the configuration of the fourth embodiment, and FIG. Is a diagram showing the time chart of FIG. 7, and FIG. 9 is a diagram showing the effect of the horn. 1 ... Ultrasonic transmitter, 2,4 ... Horn 3 ... Ultrasonic receiver, 5 ... DUT 6 ... Ambient object, 11 ... Transmission circuit 12 ... Timing circuit, 13 ... Power amplification circuit 14 …… AND circuit, 15 …… Pre-stage amplification circuit 16 …… Peak hold circuit 17 …… Sample hold circuit 18 …… Output circuit, 21 …… Oscillation circuit 22 …… Power amplification circuit, 23 …… Prefix Amplifier 24 …… Detection circuit, 25 …… Low pass filter circuit 26a, 26b, …… Peak hold circuit 27 …… Sensitivity adjuster, 28 …… Comparison circuit 29a, 29b …… Output circuit

Claims (1)

[Claims] 1. An ultrasonic wave transmitting device for transmitting an ultrasonic wave, and an ultrasonic wave transmitting device which is disposed so as to face the ultrasonic wave transmitting device, and moves between the facing ultrasonic wave transmitting device relative to the ultrasonic wave transmitting device. An ultrasonic wave receiver that receives the ultrasonic wave that has passed through the object to be measured, and a wall body that reflects the ultrasonic wave is arranged around the ultrasonic wave transmitter and the ultrasonic wave receiver. In the ultrasonic seam detector, a horn for sharpening the directivity or directivity of ultrasonic waves provided on at least one of the transmitting surface of the ultrasonic transmitter and the receiving surface of the ultrasonic receiver. And a seam detection unit that detects a seam by comparing the transmitted and received waves of the normal part and the seam of the measured object received by the ultrasonic wave receiver with a predetermined reference value. A detection unit that detects the output of the ultrasonic receiver and detects a signal according to the magnitude of the transmitted reception; A peak hold circuit for holding the peak value of the output of the reference value, a reference value generation circuit for generating the predetermined reference value from the peak value held by the peak hold circuit, an output of the reference value generation circuit and an output of the detection section. And a comparison circuit that compares the output of the comparison circuit with an output circuit that outputs the seam detection signal based on the output of the comparison circuit and that resets the peak hold circuit during the output time of the seam detection signal each time the seam detection signal is output. An ultrasonic seam detector characterized by being provided.