JPH0627803B2 - Ultrasonic device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic device, and more particularly, to an ultrasonic device that detects proximity by using ultrasonic waves.

(Prior art and its problems) It is known that the application range of a playback type robot apparatus can be expanded by using a sensor output signal for robot control. That is, in the playback type robot device,
It was necessary for the work object to be placed at a predetermined position and in a predetermined posture, but the position, posture, etc. of the work object can be accurately detected by various sensors attached to the robot device. In this case, the restrictions on the position, posture, etc. of the work object are alleviated. A robot apparatus that autonomously determines a work procedure and work contents using output signals from various sensors is also called an intelligent robot apparatus. Practical application of various sensors is the key to the realization of intelligent robot devices. One of such sensors is a proximity sensor. The proximity sensor is a sensor that detects a distance between the sensor and an object to be detected, and various methods have been proposed in the past. For example, a sensor using ultrasonic technology, a sensor using a resonance circuit of a coil / capacitor, a sensor using eddy current, and the like. However, the latter two have a drawback that they have no detection function for plastics, wood, etc., because they are required to be detection targets of metal. Further, in the former case, an ultrasonic transmitter and an ultrasonic receiver are combined, and beam-like ultrasonic waves having directivity emitted from the transmitter are reflected by a detection target, and the reflected wave is detected by the receiver. It is characterized by this. However, usually, only a single transmitter and a single receiver are combined, and it is not possible to change or scan the emitting direction of the beam-shaped ultrasonic wave, or the receiving direction. It is possible. Therefore, the detection target can only be roughly captured, and the shape of the detection target,
Due to the size, it was difficult to accurately detect the distance. On the other hand, it is well known that ultrasonic technology is applied to medical diagnostic equipment. In such an application field, the human body can be regarded almost as the same thing as water, and the characteristics of a higher sound velocity than in air and less propagation loss than in air are utilized. In addition, in the apparatus, the ultrasonic transmitter and receiver are configured by linearly arranged element arrays, and ultrasonic transmission pulses to each element that configures the array, and ultrasonic waves that reach each element. By individually changing the delay time of the voltage signal generated by the sound wave reception pulse,
By changing the beam direction of the received wave, a tomographic image inside the human body is obtained. In the applied field, research has been conducted to make the tomographic image clearer, but the results of the research are
The present invention is not always directly applied to the proximity sensor.
As an example, a difference in sound velocity in a medium that transmits ultrasonic waves, a difference in propagation loss in the medium, and the like are factors that hinder the application. Furthermore, considering the mounting of the sensor on the robot device, the outer shape of the sensor is small, and
There is also a demand for downsizing and simplification of the signal processing circuit. As described above, in the conventional proximity sensor, the distance information to the detection target is not reliable, and there is a difficulty in applying the ultrasonic technique in the medical diagnostic apparatus.

(Object of the Invention) An object of the present invention is to eliminate the drawbacks of the prior art and to provide an ultrasonic device as a proximity sensor that facilitates application to a robot device.

(Structure of the Invention) According to the present invention, an ultrasonic wave having a proximity sensor that emits a directional ultrasonic beam, receives a reflected wave from the detection target, and detects a distance from the detection target In the device, an ultrasonic element array having elements capable of generating ultrasonic waves arranged in a one-dimensional or two-dimensional array, and a pulse generator for intermittently generating burst ultrasonic transmission pulses And a plurality of delay circuits that have different delay times and are provided in parallel for each of the elements forming the ultrasonic element array so that the time difference between the ultrasonic transmission pulses supplied from the pulse generator can be a desired relationship. And a delay circuit device which is set to, by exciting each element with a pulse having a plurality of different delay times created by the delay circuit, In the intermittent period which is the period of the burst pulse, the ultrasonic beam having directivity is emitted in a plurality of different directions in a plane perpendicular to the transmitting surface of the ultrasonic element array, and the time difference between the ultrasonic transmitting pulses is increased. Ultrasonic waves characterized by changing the directivity in a plurality of directions that the ultrasonic beam has for each intermittent cycle or between different intermittent cycles by changing each of the intermittent cycles or between different intermittent cycles. The device is obtained.

(Example) Next, detailed description will be given with reference to the drawings.

FIG. 1 is a diagram illustrating a conventional sensor using ultrasonic technology. In the figure, 1 is an ultrasonic transmitter, 2 is an ultrasonic receiver, 3 is a directivity pattern showing the directivity of the ultrasonic beam emitted from 1, and 4 is the directivity of the received ultrasonic wave. Directivity patterns 5 and 6 are detection targets. FIG. 2 is a diagram showing the operation of the sensor shown in FIG. 1, in which the time change of the waveform is shown. In the figure, 10 is an ultrasonic waveform emitted from 1, and 11 is a waveform received at 2. At time t ₀ , ultrasonic waves 12 having directivity patterns of 1 to 3 are emitted. An ultrasonic waveform composed of two sinusoidal cycles is illustrated in FIG. The radiated ultrasonic waves reach the detection target 5 existing in the area covered by the directional patterns 3 and the ultrasonic waves are reflected on the surface of the detection target 5. Due to the reflection, a reflected wave of an ultrasonic wave as if a sound source is present at 5 is generated, and the reflected wave travels toward the receiver 2. Since 5 is present in the area covered by the directivity pattern of 4, a part of the reflected wave reaches 2, and in the received waveform illustrated in 11, a waveform 13 corresponding to 12 has a waveform 13 after time t _1. Observed. The time difference from time t _{0 to} t ₁ is
If the ultrasonic wave is emitted from 1 and reflected at 5 and then reaches 2 and the sound velocity of the ultrasonic wave in the propagation medium is constant, a spatial distance of 1, 5, 2 Will correspond to. For this reason, if the time between t ₀ and t ₁ is measured, the distance to the detection target 5 can be estimated, and the configuration of FIG. 1 can be used as the proximity sensor. However, in the configuration of FIG. 1, the shape of the detection target 5 cannot be determined, and it is only possible to know the presence or absence of 5. Further, the detection target 6, which is actually closer than the detection target 5, cannot be detected because it does not exist in the area covered by the directivity patterns of 3 and 4. Since the transmitter 1 and the receiver 2 are normally mounted in a common housing (not shown), in the example shown in FIG. 1, when both 1 and 2 are moved in the direction of 5, Before the casing reaches 5, there is a risk of colliding with 6. For this reason, the conventional example shown in FIG. 1 can be said to be unsuitable as a proximity sensor for a robot device.

FIG. 3 is a diagram showing an ultrasonic device according to the related art, which is applied to a medical diagnostic device. In the figure, 20a, 20
Symbols b, ... Can generate ultrasonic waves, and show a structure in which four elements are arranged in a one-dimensional array.
The element is made of an inorganic, organic or composite piezoelectric material, electrostrictive material, magnetostrictive material, or a combination thereof. 21a, 21b, ... Are amplifiers provided for the respective 20a, 20b ,. Reference numeral 22 is an original oscillator that intermittently supplies burst ultrasonic wave transmission pulses to each element forming the array, and its output is input to delay circuits 23a, 23b, ... Having different delay times. Each output of the delay circuit is input to the amplifier. Figure 4 is the third
It is a figure explaining operation | movement of a figure, and the waveform timing in a main component is shown. In the figure, 122 is an output waveform of 22 and 121a, 121b, ... Are output waveforms of 21a, 21b ,. The pulse waveforms of 122 are delayed by different times due to 23a, 23b, ... Shown in FIG. 3, and the delayed pulses are delayed by 21a, 21b ,.
Amplified to the desired voltage level needed to excite ...
A pulse having the waveform shown in a, 121b, ... Is obtained. The 121
20a, 20 excited by the waveforms a, 121b, ...
The ultrasonic waves having the wavefronts conceptually shown by 24a, 24b, ... in FIG. 3 are emitted into the medium 25 from b ,. That is, as shown in FIG. 4, the ultrasonic wave is emitted from the element of 20a earliest in time, and the ultrasonic wave is emitted from the element of 20d earliest in time. Due to the difference in the emission time and the burst shape of the ultrasonic wave as shown in FIG. 4, the wavefronts corresponding to any instantaneous value of the output of the original oscillator 122 are 24a, 24b, It will have the spatial distribution shown in.

Since the wavefronts 24a, 24b, ... Show spatially instantaneous values, the wavefronts are combined, and the combined wavefront shape exemplified by 26 is formed in the medium 25. If the wavefronts of 24a, 24b, ... Travel at a constant velocity in 25, the synthesized wavefront 26
Goes straight in a direction perpendicular to 26 (indicated by 27 in FIG. 3). That is, it can be considered that the ultrasonic beams in which the ultrasonic energy is concentrated are emitted only in the direction 27 from the element arrays 20a, 20b, .... 27
The direction of is determined by the emission time difference of the ultrasonic waves from 20a, 20b, .... In other words, 121a individually supplied to each element within an arbitrary intermittent cycle illustrated in 122 of FIG. 4, for example, within a cycle indicated by τ _{0 in} the figure,
121b, ..., the time difference of the ultrasonic pulses (in FIG. 4, θ
₀ , θ ₁ , θ ₂ , θ ₃ ) are set to a desired relationship so that the ultrasonic wave is generated in any one direction in the plane perpendicular to the array within the period, for example, 27 directions. Can emit a beam. Next, another period following τ ₀ (in FIG. 4, τ ₀
(Denoted as ₁ ), the time differences corresponding to θ ₀ , θ ₁ , ... Are changed to θ ₀₁ , θ ₀₂ ,. In FIG. 4, θ ₀₁ , which is smaller than θ ₀ , θ ₁ , ...
theta _02, but ... are shown, in such a case, the radial direction 27 in Figure 3 is closer to the vertical direction of the array. In other words, by changing the time difference,
By changing the radiation direction of the ultrasonic transmission wave, the region to be detected can be scanned with the ultrasonic beam. Next, the ultrasonic beam emitted according to the above operation is reflected by the detection target 28 existing within the reach of the beam,
Form a reflected wave pattern having a circular wavefront 29 as if a point sound source were present. In FIG. 3, 28 is drawn so that it does not exist in the radial direction of 27, but this is for the purpose of avoiding a complex line in drawing, and it is considered that 28 exists in the direction of 27 in reality. The wavefront 29 sequentially reaches the elements 30d, 30c, ... Having a sound pressure / electricity conversion function with the lapse of time. The elements 30a, 30b, 30c, 30d are 20a, 20b,
It has a function opposite to that of, for example, an inorganic, organic or composite piezoelectric material, an electrostrictive material, a magnetostrictive material, or a combination thereof. The electric signals from 30a, 30b, ... Are input to the delay circuits 33a, 33b, ... Which have different delay times, respectively, and the plurality of delayed output signals from the delay circuits are added to the single output terminal 34. Is output. With respect to the illustrated wavefront shape 29, similar reflected ultrasonic signals are sequentially detected at 30d, 30c, 30b, and 30a as time passes. The time difference of the reflected ultrasonic waves reaching the element is compensated by appropriately setting the delay time of 33d, 33c, 33b, 33a, and at the output of the delay circuit,
The detection signals at 30d, 30c, ... Are made to have the same time. That is, by changing the delay time of 33a, 33b, ..., It is possible to electronically provide a focused wave function to the reflected wave from the detection target existing in the arrival area of the radiated ultrasonic wave. Become. According to the configuration of FIG. 3 described above, it is possible to detect a two-dimensional ultrasonic image of the detection target existing in front of 20a, 20b, ... And 30a, 30b ,. It becomes possible to easily detect the shape of the object and the distance from the arrival time of the ultrasonic image to the object to be detected, and it can be used as a proximity sensor mounted on a robot apparatus.

However, there are serious drawbacks when the configuration of FIG. 3 is applied to the proximity sensor. The drawbacks will be described below. As a proximity sensor in a robot device,
It is required that a detection target existing within a distance of up to 50 cm can be accurately detected. In a normal industrial robot apparatus, the propagation medium of the emitted ultrasonic waves is air, so the propagation speed of the ultrasonic waves is 340 m / se in the air.
is equal to c. If the distance to the detection target is 50 cm, the ultrasonic wave propagates a distance of 1 m round trip, and the time required to propagate the distance is about 3 msec. That is, the periods τ ₀ and τ ₁ shown in FIG. 4 must be set to 3 msec or more. In order to change the radiation direction shown by 27 in FIG. 3 every 1 ° to cover the 90 ° omnidirectional range, it is necessary to radiate the ultrasonic wave 90 times, and the detection within the omnidirectional range is required. It takes about 270 msec to detect the target. If the reciprocal of the scanning period in the omnidirectional range is defined as the frame frequency, the frame frequency is 3.
It becomes 7 Hz. It is clear that the frame frequency of 3.7 Hz is too low for controlling robotic devices. In other words, based on the ultrasonic image that appears at 3.7 times per second, when moving a part of the robot apparatus, for example, the arm, it becomes difficult to move at a high speed, and the productivity of the industrial robot apparatus decreases. Further, there is a serious drawback that the device is difficult to apply in the field where high-speed response is required.

The present invention has been made to avoid the above drawbacks, and FIG. 5 shows an embodiment of the present invention. FIG. 1A is a partial configuration example of the ultrasonic device according to the present invention, and FIG. 1B is a diagram showing timing. In the figure, 50a, 50b, 50c,
50d is an element capable of generating ultrasonic waves, and a structure in which four elements are arranged in a one-dimensional array is illustrated.
The element is any one of a piezoelectric substance, an electrostrictive substance and a magnetostrictive substance made of an inorganic material, an organic material or a composite material, or
The combined substance is the main constituent. Also,
51a, 51b, 51c and 51d are respectively 50a, 50b, 50c,
It is an intermittent burst-like ultrasonic transmission pulse waveform supplied to 50d. The elements 50a, 50b, 50c, and 50d have two groups of the pulses, 61a and 65a, 61b and 65b, 65c and 61c, 65d and 61d, respectively, within the arbitrary interrupting period 40.
Is being supplied. By the pulse, 50a, 50b, ...
The instantaneous wavefront of the ultrasonic waves emitted from the
, 62a, 62b, ..., 66a, 66b ,. Same figure
If you refer to the pulse supply timing in (b),
The wavefronts corresponding to the pulses a, 61b, 61c, 61d, 65a, 65b, 65c, 65d are 62a, 62b, 62c,
It is clear that they are 62d, 66a, 66b, 66c, 66d. In the ultrasonic propagation medium 63 existing on the front surface of the element,
Since wavefront synthesis is performed, 62a, 62b, ..., 66a,
The wavefront synthesized by 66b, ... Has the shape shown by 70, 71, and the synthesized wavefronts 70, 71 are respectively the directions of emission 72,
Proceed to 73. More specifically, 62a,
The wavefront synthesized by 62b, 62c, 62d is 71, 66a,
The wavefront synthesized by 66b, 66c and 66d becomes 70. By supplying the ultrasonic transmission pulse to an element group array capable of generating ultrasonic waves, within the cycle 40,
It can be seen that the ultrasonic waves can be emitted in different directions 72, 73 in the plane perpendicular to the array. Within the cycle 40, the ultrasonic transmission pulses 51a, 51b, which are individually supplied to the respective elements,
By appropriately setting the time difference between the two, the shaped wavefront (for example, 7) is shaped in the desired radiation direction (for example, 72, 73).
0, 71) can be realized. Further, in the cycle 41 following the 40, as shown in FIG. 5, the time relationship between the pulse trains of the two burst groups 51a, 51b, ... Is different. That is,
61a, 61b, 61c, 61d delay time difference θ ₁₀ ,
Delay time difference within the corresponding 41 corresponding to θ ₁₁ and θ ₁₂ θ ₂₀ and θ
₂₁ and θ ₂₂ are each larger than the value within 40. In this relationship, the composite wavefronts corresponding to 70 and 71 are
The inclination in Fig. 5 (a) becomes closer to vertical, and at the same time,
The angle formed by the two radial directions becomes larger. That is, the time difference can be changed for each cycle, and the direction of the radiation can be changed for each cycle. Further, in the present embodiment, since the two ultrasonic waves are radiated at the same time or approximately the same time in any given cycle, the detection target existing in the omnidirectional range of radiation of 90 ° as described above. The number of times of radiating the ultrasonic wave for detecting all of the above is 45 times. That is, the above-mentioned frame frequency is increased to 7.4 Hz, and there is an effect that the upper limit of the operation speed of the arm can be doubled for the control of the robot apparatus. In the description of FIG. 5, a two-cycle rectangular wave pulse is used for a one-dimensional array having four elements, but the present invention is not limited to this. That is, the number of elements may be a natural number, the array shape may be one-dimensional, and the number of pulse repetitions and the pulse shape are not limited.
Further, the pulse crest values to 50a, 50b, 50c, and 50d do not have to be constant values, have different crest values for each element within the period, and the crest values change for each period. May be. When the number of elements is odd, it is possible to set the sound pressure of ultrasonic waves emitted from the element located at the center of the one-dimensional array to twice the sound pressure of ultrasonic waves emitted from other elements. desirable. Further, the delay time difference within the same period in FIG. 5 (b) is set to be constant, but the radiation direction is left-right asymmetrical (72 and 73 in FIG. 5 (a) are left-right symmetrical directions. Furthermore, the delay time difference may be set to a desired relationship in order to make the composite wavefront concave in the radial direction and concentrate the sound pressure in the vicinity of a specific distance from the array. In the case of such a concave shape, it is preferable that the direction of the radiation is fixed over a plurality of the cycles, only the curvature or shape of the concave shape is changed for each cycle, and the specific distance is changed for each cycle. Also, the cycle 40 or 41
It is also possible to radiate the ultrasonic wave in N different directions in the cycle by arranging N pulse groups in the inside. In such a case, the frame frequency described above is (3.
It is increased up to 7 × N) Hz to further improve the operation speed of the arm described above. Further, the ultrasonic waves may be repeatedly emitted while maintaining a certain time relationship within a plurality of continuous cycles. Although there is a drawback in that the frame frequency is reduced in this operation, since the reflected wave pattern from the detection symmetry is the same within the period, the S / N ratio is calculated by performing the average value calculation on the ultrasonic receiving circuit side. And the detection accuracy can be improved.

FIG. 6 is an example of a configuration for realizing the timing shown in FIG. 5 (b). In the figure, the same numbers as in FIG. 5 are the same components. In the drawing, 50a, 50b, ... Are shown as separated, but they may be integrated as shown in FIG. In the figure, outputs from an original oscillator 84 that generate 184 waveforms are delay circuits 82a, 82b, 82c, 82d, 83a, 83b, 83c having different delay times.
It is input to 83d. The output from the delay circuit is the adder circuit 81.
a, 81b, 81c, 81d, and the output of the adder circuit is an amplifier circuit 80a having an amplifying function, a waveform shaping function, and the like.
80b, 80c, 80d, and the output of the amplifier circuit is
It is input to 50a, 50b, 50c and 50d. Since the operation of such a configuration can be easily understood by those skilled in the art, a detailed description is omitted and only the waveform to 50a is described. The 184 burst waveform generated at 84 is
It is delayed by τ _{10 to} 82a and becomes a waveform of 182a. The 184 is delayed by 83a for a time of τ _{11 and} 183a
Becomes the waveform of. The waveforms of 182a and 183a are then added by 81a and further amplified by 80a to a voltage level sufficient to excite 50a, resulting in a waveform of 180a. The 180a is supplied to 50a, and ultrasonic waves are emitted from 50a. In the present embodiment, all the waveforms of each part are displayed as bipolar burst pulses having positive, zero, and negative ternary levels, but the present invention is not limited to this. For example, 184, 182a, 183
All of a and 180a may be sine wave burst pulses. Further, 184, 182a, 183a are logic circuit output waveforms having zero and positive binary levels, which are represented by TTL logic circuits, and may be converted into desired waveforms by 80a. In this case, 84, 82a, 83a, 81a, etc. should be replaced with TTL or CMOS.
It has the advantage that it can be configured with an IC shift register or random access memory. If 82a, 83a, etc. are composed of known charge-coupled devices, it does not depend on the shape of the output waveform of 84, and delays in an analog manner for a predetermined delay time while maintaining the shape of the output waveform. Will also be possible. 80a,
80b, ... Have the function of amplifying and converting the waveform to the desired voltage level necessary for exciting 50a, 50b ,.
If the output signals of a, 81b, ... Have a level and waveform sufficient for the excitation, 80a, 80b, .. can be omitted. The radiation direction of the ultrasonic wave described in FIG. 5 is
Since it depends on τ ₁₀ and τ ₁₁ in FIG. 6, the direction of the radiation can be changed by appropriately setting the delay time in the delay circuits such as 82a and 83a to a desired value. In particular, in the configuration of FIG. 6, 82a and 83d, 82b and 83c, 82c and 83b,
If 82d and 83a are set so as to obtain the same delay time, the direction of radiation is always symmetrical. The situation is shown in FIG. In the figure, the same numbers as in FIG. 6 indicate the same components. In the figure (a), 72 and 73 of FIG. 5 are shown, and in the figure (b),
Compared to the case of FIG. 9A, two symmetrical radial directions 90 and 91 when the time relationship is different are shown.
That is, to the first region 93 on the left side of the center line 92 passing through the center of the one-dimensional array of 50a, 50b, ... Shown in FIG. 7 (a), 82a, 82b, 82c, 82d are provided. The ultrasonic wave emitted by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave is processed by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic wave. . In addition, in order to realize this situation, 82 in FIG.
, 82a, 82b, ..., 83a, 83b, ... As shown conceptually by the difference in length on the drawing, the delay times 82a, 82b, 82c,
It is necessary to increase the length in the order of 82d, and at the same time, in the order of 83d, 83c, 83b, 83a.

FIG. 8 is a diagram showing a configuration example of the elements 50a, 50b, 50c, 50d capable of generating the ultrasonic waves of FIG. 5 (a). FIG. 3A shows a configuration example in which electrodes 96 and 97 are provided on both surfaces of the piezoelectric body 95. The material of 95 is ZnO, PZT, PLZ
A wide range of materials such as inorganic materials such as T and AlN, organic materials such as PVDF, hybrids that are a mixture of inorganic materials and organic materials can be selected. Further, the 96 and 97 have high adhesiveness with 95,
Any material can be selected as long as it can maintain good reliability against piezoelectric vibration of 95. In the configuration example, the ultrasonic wave transmission pulse is supplied to 96 and 97, and the well-known inverse piezoelectric effect causes 95 to vibrate and emit ultrasonic waves. The 95, 96, 97
The structure consisting of may be fixed on the silicon substrate with an adhesive, paste or the like via an insulating means. Fig. 8
(b) is an example of the configuration when the silicon integrated circuit technology is used. In the figure, 100 is a silicon substrate having a first conductivity type, 101 and 102 are diffusion layers having a conductivity type different from 100, 10
3 is an insulating film, 104 and 106 are electrodes, and 105 is a thin film piezoelectric film. The material of 105 is considered to be the same as that of 95, but ZnO and Al, which can easily obtain a piezoelectric thin film by the sputtering technique.
N or the like is desirable. In this configuration, by supplying the ultrasonic wave transmission pulse to 104 and 106, 105 can be vibrated and ultrasonic waves can be emitted in a direction perpendicular to 100. Further, in the configuration, if 104 is separated from an external circuit (not shown) to be in a floating state and 106 is connected to a DC voltage source as appropriate, ultrasonic waves arriving in a direction perpendicular to 100 will cause a known error. It is possible to induce charges in 105 according to the piezoelectric effect. The induced charge modulates the channel current of a FET provided with means to be appropriately biased so that 101 acts as the source and 102 acts as the drain, so the configuration can be used as an ultrasonic detector. Have advantages. That is, since the structure functions not only as the ultrasonic wave transmitting element in the present invention, but also as the element having the sound pressure / electric conversion function exemplified as 30a, 30b, ... in FIG.
There is an advantage that the ultrasonic device in the form of IC can be realized.

(Effects of the Invention) The present invention has been described above in detail with reference to the drawings. It should be noted that although the description is limited to the transmission of ultrasonic waves in the description, the conventional example of FIG. 3 can be applied to the reception of reflected waves. Of course, in the present invention, since the ultrasonic pulse is emitted in a plurality of emission directions, it is necessary to prepare the plurality of sets of the configuration for reception illustrated in FIG. According to the present invention, there is an advantage that a detection target object existing in the air can be detected at a high frame frequency, and the shape of the object and the distance to the object can be easily and accurately detected.

[Brief description of drawings]

FIG. 1 is a conventional sensor using ultrasonic technology, and FIG. 2 is a diagram for explaining the operation of FIG. FIG. 3 is a diagram for explaining a conventional ultrasonic device, and FIG. 4 is a diagram for explaining the operation of FIG. 5 (a) and 5 (b) are views showing an embodiment of the present invention. Fig. 6
(a), (b), FIG. 7 (a), (b), FIG. 8 (a), (b) are views for explaining a concrete example for realizing the embodiment of FIG. . In the figure, 1 ... Ultrasonic transmitter, 2 ... Ultrasonic receiver, 3,4 ... Directional pattern, 5,6,28 ... Detection target, 10 ... Ultrasonic waveform, 11 ... Received waveform , 20a, 20b,
20c, 20d, 50a, 50b, 50c, 50d ... Elements capable of generating ultrasonic waves, 21a, 21b, 21c, 21d ...
Amplifier, 80a, 80b, 80c, 80d ... Amplifier circuit, 23a,
23b, 23c, 23d, 33a, 33b, 33c, 33d, 82a, 82
b, 82c, 82d, 83a, 83b, 83c, 83d ... delay circuit, 22, 84 ... original oscillator, 30a, 30b, 30c, 30d ...
Elements having sound pressure / electricity conversion function, 24a, 24b, 24c,
24d, 29, 62a, 62b, 62c, 62d, 66a, 66b, 66
c, 66d ... wavefront, 26, 70, 71 ... synthesized wavefront, 2
7, 72, 73, 90, 91 …… Radiation direction, 34 …… Output terminal, 1
22, 121a, 121b, 121c, 121d, 51a, 51b, 51c, 51
d, 184, 182a, 183a, 180a ... Waveform, 40, 41 ... Period, 81a, 81b, 81c, 81d ... Addition circuit, 92 ... Center line, 93, 94 ... Region, 95 ... Piezoelectric body , 105 ・ ・ ・ Thin film piezoelectric film, 96, 97, 104, 106 ・ ・ ・ Electrode, 103 ・ ・ ・ Insulating film, 10
0 ... Silicon substrate, 101, 102 ... Diffusion layer.

Claims (1)

[Claims] 1. An ultrasonic device having a proximity sensor that emits a directional ultrasonic beam and receives a reflected wave from a detection target to detect a distance to the detection target. The elements that can be generated have an ultrasonic element array having a structure arranged in a one-dimensional or two-dimensional array, a pulse generator that intermittently generates burst-shaped ultrasonic transmission pulses, and a different delay time. A delay circuit device that sets a time difference between ultrasonic transmission pulses supplied from the pulse generator to a desired relationship by a plurality of delay circuits that are provided in parallel for each element that forms the ultrasonic element array. And a basic burst pulse generated by the pulse generator by exciting each element with a pulse having a plurality of different delay times generated by the delay circuit. In an intermittent cycle which is a cycle, an ultrasonic beam having directivity is emitted in a plurality of different directions in a plane perpendicular to the transmitting surface of the ultrasonic element array, and the time difference between the ultrasonic transmission pulses is the intermittent cycle. An ultrasonic device, characterized in that the directivity in a plurality of directions of the ultrasonic beam is changed for each intermittent cycle or for different intermittent cycles by changing it for each intermittent cycle or for different intermittent cycles.