JPS61272674A - Ultrasonic switch - Google Patents

Abstract

PURPOSE:To shorten a parallel distance and to improve a response speed by varying the pressure of transmitted sound and discriminating the transmitted wave. CONSTITUTION:When a pattern generator 11 generates a pattern on the basis of a preset pattern, a gate generator 10 outputs an L gate signal (b) and an H gate signal (c). The output voltage of a voltage switching circuit 12 is controlled, for example, from 20V to 40V on the basis of those signals (b) and (c) and drives a next-stage voltage driver 7, so a coded transmitted carrier (d) is obtained in correspondence to the pattern. This coded transmitted carrier (d) is used to transmit a wave and a reflected wave from a body is received by a receiving circuit 3 to send out a reception output (o) only when the code of the transmitted wave is coincident. Therefore, a sound pressure controller 6 varies the sound pressure of the transmitted wave and discriminates the transmitted wave to increase the response speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of the Invention The present invention relates to an ultrasonic switch having a wave transmitting circuit formed by connecting an ultrasonic vibrator to the output stage of a heavy duty driver for obtaining a predetermined sound pressure.

(B) Front of the Invention Conventionally, when using the ultrasonic switch of the above example in two sets adjacent to each other, in order to prevent malfunction due to mutual interference,
Normally, the parallel installation distance is set to about three times the maximum detection distance.

In order to prevent the above-mentioned mutual interference, it is possible to improve the directivity by narrowing the sound pressure half angle or to vary the transmission frequency, but in any case, it is impossible to improve the response speed. It's impossible.

In other words, in the past, in order to avoid multiple reflections, bombing, frontal effects, etc., it was not possible to transmit waves until the reflected wave level (received wave level) became sufficiently low, and as a result, response speed was improved. There was a problem that it could not be done.

This is the same even when using only one set of ultrasonic switches; with conventional ultrasonic switches, it is not possible to clearly distinguish between the waves received in the current cycle and the waves received in the next cycle. We had a problem person who was unable to increase the response speed.

(C) Purpose of the Invention This invention aims to improve the transmission of waves by varying the sound pressure of the transmitted waves.
The object of the present invention is to provide an ultrasonic switch that can be identified by pressure changes, shortens the parallel distance, and improves response speed.

(D) Summary of the Invention The present invention is characterized in that it is an ultrasonic switch in which a sound pressure control means for variably controlling the transmitted sound pressure is connected to the input stage of an electric driver that obtains a predetermined sound pressure.

(E) Effects of the Invention According to this defense, since the above-mentioned sound pressure control means can change the sound pressure of the transmitted wave and differentiate the transmitted wave,
For example, if the sound pressure is varied for each wave transmission, due to various reflections, pumping, frontal effects, etc., the next period's foul wave or the reflected wave from the adjacent ultrasonic swing J that does not come to the original receiving signal will be received. By determining whether or not it is a radio wave, it is possible to avoid false detections due to these waves, shorten the transmission cycle to improve response speed, and reduce the distance between parallel installations. This has the effect of shortening the time.

In other words, by controlling the '+: A wave & pressure, it is possible to identify the transmitted wave, so it is possible to clearly identify the transmitted wave by receiving other transmitted waves and receiving the own transmitted wave that should originally be received. You can do it.

(f) Embodiment of the Invention An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows an ultrasonic switch, and in FIG. This is a one-element anti-type switch equipped with a wave receiving circuit 3 that receives sound waves through the same vibrator 2.

The above-mentioned wave transmitting circuit 1 includes a tuning circuit 5 at the output stage of an oscillation circuit 4.
A voltage driver 7 is connected via the sound pressure control means 6, and the above-mentioned ultrasonic transducer 2 is connected to the output stage of the voltage driver 7, resulting in the configuration 1.

The voltage driver 7 described above is a circuit for obtaining a predetermined sound pressure,
Sound pressure control means 6 connected to the input stage of this voltage driver 70
is a pulse driver 8, a pulse counter 9, and a goo 1.
pattern generator 10, pattern generator 11, and 1ffi I
It is equipped with a switching circuit 12, etc., and a wave transmitting circuit 13 is connected between the pulse driver 8 and the pattern generator 11 described above.

Here, the above-mentioned wave transmission gate 13 is a circuit that sets the wave transmission time t1 and the wave transmission repetition period.
As shown in the figure, the J wave transmission goo 1~signal a@ is obtained.

Here, the above-mentioned pulse driver 8 connected to the output stage of the wave transmission gate 13 transmits a square wave at a transducer drive frequency of, for example, 40 to 11, set by the tuning circuit 5 at the previous stage, for a transmission time of 1.
1, and this pulse driver 8 outputs the second pulse.
As shown in the figure, for example, a number of pulses i-t 40 drive pulses e@ are obtained.

A pulse counter 9 connected to the output stage of the pulse driver 8 counts the drive pulses e output from the pulse driver 8. Output to counter 1, 26th
The generator generates a second count output that counts the number 1 pulse to the 40th pulse.

The aforementioned goo 1 connected to the output stage of this pulse counter 9
The signal generator 10 has two output lines 10b and 10G for controlling the output voltage of the voltage switching circuit 12, and one output line 10b has a first counter 1-1 during output.
-1 signal and, during the second count output, a 1] signal based on a preset pattern, and the J1-gate signal shown in FIG. 2 is obtained on the output line 10b.

In addition, the other output line 10c receives a 1- signal during output of the first count I, and a 1-1 signal based on a preset pattern during output of the second count.
An L signal is output, and an l-1 gate I signal C shown in FIG. 2 is applied to this output line 10G.

The pattern generator 11 that presets the above-mentioned pattern is
It has an 11-bit output (see Figure 2), and the upper 3 bits are always set to -1 signal as a start signal, and the next lower 2 bits are sent to the 1 signal.] - Transmission gate signal from 13
For each application, L l-→l-11-→1-11→Hl-1→
By repeating the change of LL, the remaining 6 bits can be set to -code, and the settings of these 6 bits are set in advance to remain unchanged. In this embodiment, for example, r l-1
1HL HI J, that is, it is set to the - code of "101010".

The pattern output from the pattern generator 11 set in this way is applied to the gate generator 10 described above. ') c to (1, J1 goo 1 shown in Figure 2)
- signal 1) and gate 11 gate 18 gate switching circuit 12
Output to.

This voltage switching circuit 12 has a 510 pol I-power input,
1-Goo I signal Suga [When 111, converts to 20 pol 1 output, 11 ge 1 ~ signal 0 converts to r Hj sweetfish 40 pol 1 ~ output, and at other times of A 0pol 1~
It is converted into an output to control the lightning F1-driver 7 at the next stage.

This electric F "driver 7" is a series of electric low switching circuits 12
Since the drive pulse from the pulse driver 8 in the previous stage is applied to the ultrasonic transducer 2,
The number of J transmit carriers d shown in the figure can be 437.

This transmitting kitria (1 is the ultrasonic vibrator 2 and the ultrasonic vibration 1
It is steered by energy and emitted into the air q4, which hits an object in front and is reflected.

This reflected ultrasonic vibration energy is again converted into an electric signal by the ultrasonic transducer 2 mentioned above, and becomes a receiving carrier f shown in FIG.

The receiving side output stage of the ultrasonic transducer 2 described above amplifies the received signal f as a received signal and outputs a half-wave rectified output and <r
A detector 15) is connected through the amplifier 14, and the detector 15 performs envelope detection of the half-wave rectified output to obtain the detected output q shown in FIG.

Further, a first comparator 16 is connected to the output stage of the above-mentioned wave detector 15, and this first comparator 16 compares the above-mentioned detection output q with a preset reference potential to generate a waveform shaped output. obtain.

A pulse counter 19 is connected to the output stage of the above-mentioned amplifier 14 via a sampler 17 and an integrator 18, and the half-wave rectified output is non-bringed by 1 at the sampler 17 in (a) above to obtain a sampled output. "C1 This sampled output is integrated to the range possible by an integrator 18 having an RC configuration, and
J
The high frequency component noise is cut off and applied to the CP terminal of the next stage pulse counter 19.

The output J of the first comparator 16 (previously) 41 is applied to the C1 terminal of this pulse counter 19, and when the output of the first comparator 16 is "11", 1] The clock input (the above-mentioned sampling output) is enabled, and when a predetermined number of clock pulses, for example, 15 or more pulses are input, the output of the counter 19 is set to [111 by 1]. In other words, the counter output i shown in FIG. 3 is obtained.

The analog switch 20 connected to the output stage of the above-mentioned wave detector 15 is configured to apply this counter output i.
0) of l-J is on state and i! When the input potential and the output potential become equal, and the counter output i is 111, the output is set to zero.

A voltage holding circuit 2 is provided at the output stage of this analog switch 20.
1 is connected, and this voltage holding circuit 21 holds the voltage at the falling edge of the output of the above-mentioned Arilog switch 20, and obtains a holding output j in which the output is set to zero at the rising edge. .

An amplifier 22 is connected to the output stage of the voltage holding circuit 21 set as J:, and the amplifier 22 synchronizes with the pulse counter output i to increase the above-mentioned holding output j by 1.5 times, for example, by one node above the potential. The amplified output K is obtained.

A second comparator 23 is connected to the output stage of this amplifier 22,
This comparator 23 is configured to apply the above-mentioned detected output 0 and amplified output j, and this ratio amplifier 23 applies these two outputs a
, , j are compared, and when q>j, a comparison output ρ is obtained.

The output stage of the second comparator 23 described above includes a shift register 2.
The D terminal of 4 and the safe l-circuit 25 are connected.

This let circuit 25 has the output ' of the first comparator 16 mentioned above.
In other words, the configuration is such that the waveform shaping output is also applied, and the waveform shaping output is "11" and 3 pulses of the comparison output ρ from the second comparator 23 (the number of pulses equivalent to the start pulse) are input. In contrast, the output of this cellar 1 to circuit 25 is [1
11, and thereafter, when the waveform shaping output becomes []-'', the circuit conditions are set so that the output of the set circuit 25 becomes rLJ, and from this circuit 25, as shown in FIG.
Output m1j! −m.

This one? Apply the outputs 1 to m and the counter output i to the first AND circuit 26, apply the AND output of the first AND circuit 26 and the output of the integrator 18 to the second AND circuit 27,
Furthermore, the configuration is such that the AND output of the second AND circuit 27 is applied to the CP terminal of the shift register 24 described above.

A third comparator 28 formed by a magnitude code comparator is connected to the output stage of this shift register 24,
This third comparator 28 compares the pattern from the shift register 24 (the pattern of the lower 8 pits excluding the upper 3 bits) and the pattern from the pattern generator 11 (the pattern of the lower 8 pits excluding the upper 3 bits). The third comparator 28 is configured to output the match signal n shown in FIG. 3 at the above-mentioned 8-bit [I] when the comparison results in a match.

The output stage of this third comparator 28 is connected to a flip-flop knob 29 driven by the above-mentioned coincidence signal n, and when the transmitting and receiving carcass patterns match, the receiving wave output O is output from the Q terminal of the flip-flop knob 29. (see FIG. 3) and drives a subsequent output circuit (not shown).

In addition, the R terminal of the above-mentioned Noritsubu flop 29 is applied with the wave sending signal a from the wave transmitting gate 13, and the above-mentioned received wave output O is sent to -H set 1 for each wave transmission. It consists of

The operation of the ultrasonic switch configured in this way will be explained below.

Now, when the oscillation circuit 4 is caused to oscillate at 100 to 1 lZT'' and the wave transmission gate 13 is operated to transmit a wave, this oscillation frequency is changed to the vibrator drive frequency preset in the next stage tuning circuit 5, for example, 40 to +12 The pulse driver 8 continuously outputs square wave pulses (drive pulses) e of the same frequency within the transmission time t1.

Furthermore, the pattern generator 11 outputs two types of signals 8, 1-gate signal S and 11-gate signal C to the signal generator 10 based on a preset pattern, and each of these gate signals The output voltage from the voltage switching circuit 12 is controlled to 20 volts and 40 volts based on the voltages I and C, and the voltage driver 7 in the next stage is driven by this control voltage. Corresponding to the above-mentioned pattern, a coded transmission carrier (j) can be obtained.

In this way, a transmission wave is emitted based on the transmission wave carrier d converted into a C1]- code, and the reflected wave (reception wave) from the forward object is received in the receiving circuit 3 when the ml- codes of the transmitted and received waves match. Only the received wave output O is output.

By changing the sound pressure of the transmitted wave by the above-mentioned sound pressure control means 6, the U1 transmitted wave can be identified.

For example, the 6 bits shown in the example are r Hl l-I L
For example, the corresponding 6 pits of another ultrasonic switch installed next to the ultrasonic switch designated as Hl-1 are r L
11 L l - I L L , 1, etc. The sound pressure control means 6 described above can distinguish the transmitted waves, and furthermore, the sound pressure of the lower two bits is also changed from LL → l - I L → for each transmitted wave. [-
It is possible to change it sequentially like 11→L111→l-1-.

As a result, in addition to various reflections, pumping, background effects, reflected waves of the next cycle, and reflected waves that are originally received from another ultrasonic switch installed next to the By determining whether or not it is a transmitted wave with a corresponding cycle,
False detection can be prevented by 11J.

Therefore, it is possible to shorten the transmission period and increase the response speed.In addition, when multiple ultrasonic switches are installed in parallel, the installation distance can be shortened. There is an effect that can be done.

Note that, as shown in the embodiment, when a transmission key system is used, noise can be discriminated by carrier counting, so malfunctions caused by noise can be effectively eliminated.

Further, in the above embodiments, a -element reflection type circuit is illustrated, but it goes without saying that the present invention may be applied to a self-excited transmission type circuit or a separately excited transmission type circuit.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Fig. 1 is a block diagram showing the electric circuit configuration of an ultrasonic switch, Fig. 2 shows a time chart 1 of each part on the transmitting side, and Fig. 3 shows a time chart on the receiving side. This is a timeline of each part.

Claims (1)

[Claims] 1. An ultrasonic switch equipped with a wave transmitting circuit in which an ultrasonic vibrator is connected to the output stage of a voltage driver that obtains a predetermined sound pressure, the transmitting sound pressure being applied to the input stage of the voltage driver. Ultrasonic switch connected to variable sound pressure control means.