JPH0820319B2 - Analog switch - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an analog switch that outputs at a level according to an operation input, and makes it possible to set an operation level of an operation target according to the operation input.

"Background of the Invention" As a conventional technique, for example, there is one as shown in FIG.

That is, what is shown in the figure is a contactless switch, which is composed of an electrode plate 1, a high-frequency oscillator 2, and an on / off detection circuit 3, and operates when the finger A approaches the electrode plate 1 by changing the electrostatic capacitance P. To do.

Now, when finger A approaches electrode plate 1, electrode plate 1, finger A
Also, the electrostatic capacitance P between the ground plane 4 and the ground plane 4 changes abruptly and is input to the high frequency oscillator 2 as the output m. The oscillation frequency of the high-frequency oscillator 2 changes due to this change in capacitance, and this change in high frequency n is detected by the on / off detection circuit 3, and an on / off signal O is output.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technique, it is very difficult to take out a signal whose level is changed in an analog manner because a change in electrostatic capacitance during the switch operation is rapid. . Further, there is a serious problem that the electrode plate 2 may always be at the same potential as the ground plane 4 due to humidity or the like, and then the switching operation may not be performed.

The present invention solves these problems and is contactless and
It is an object of the present invention to provide an analog switch that can give a continuous operation input and output at a level corresponding to the operation input.

"Means for Solving Problems" An elastic body which is a member to be operated and to which an operating pressure is applied, and an ultrasonic vibration when joined to a first position of the elastic body and a predetermined AC signal is applied. And a first piezoelectric element that generates an electric field, and an operation applied to the elastic body after being connected to a second position of the elastic body that is separated from the first position and generated by the first piezoelectric element. A second piezoelectric element that generates a voltage according to the magnitude of ultrasonic vibration changed by pressure, and a control circuit that controls the output level of the switch based on the voltage generated from the second piezoelectric element. It exists in the analog switch characterized by doing.

"Operation" A predetermined AC signal is applied to the first piezoelectric element to cause predetermined ultrasonic vibration. When the elastic body, which is the operated member, is not pressed, the second piezoelectric element makes a certain ultrasonic vibration by the ultrasonic vibration transmitted through the elastic body,
Outputs a constant level AC signal.

When the elastic body is pushed, the elastic body is constrained by the operating pressure, the transmissibility from the first piezoelectric element to the second piezoelectric element changes accordingly, and an AC signal of a level corresponding to the operating pressure is output. To do.

Then, the operation condition of the operation target is set according to the output level of the second piezoelectric element.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

1 to 5 show an embodiment of the present invention, and the present invention is applied to a dimmer switch.

The switch control element 10 is formed by joining a first piezoelectric element 20 for ultrasonic wave generation to one end of an elastic body 11 and a second piezoelectric element 30 for ultrasonic wave detection to the other end.

The elastic body 11 is a member to be operated, and an operating portion 12 to which an operating pressure is applied, for example, a finger A, which is an operating member for operating, is provided in an intermediate portion.

The first piezoelectric element 20 is bonded and bonded to the elastic body 11 via the electrode 21, and is bonded to the mounting portion via the electrode 22 and the buffer material 23.

Similarly, the second piezoelectric element 30 is connected to the elastic body 11 via the electrode 31.
Are bonded to and bonded to the mounting portion via the electrode 32 and the buffer material 33.

FIG. 3 shows a circuit that controls, for example, indoor lighting, and the dimming control circuit 40 is a signal conversion unit that converts the magnitude of the amplitude of a high frequency signal into an output signal c of a DC voltage value.
41 is connected to the switch control element 10 via the inverting amplifier 15, and a delay circuit 42 for receiving the output of the signal converter 41 and a reset / hold signal generator 43 are provided. Delay circuit
Reference numeral 42 is a circuit that transmits the output signal c from the signal conversion unit 41 with a certain time delay.

Further, the dimming control circuit 40 is provided with a signal holding unit 44 which receives the output signal f delayed by the delay circuit 42 and the reset hold pulse d of the signal conversion unit 41, and the output of the signal holding unit 44. Is connected to the controlled object 50.

The reset / hold signal generator 43 is a circuit as shown in FIG. 4, and includes a differentiating circuit 46 including a capacitor C1, a resistor R1, and an operational amplifier 45, and a comparator 47 that receives the signal g differentiated by the differentiating circuit 46. And variable resistors R2 and R3 connected to the comparator 47.

As shown in FIG. 5, the signal holding section 44 is composed of a D-flip-flop 48, NAND gates 49a and 49b, and a hold circuit 40a.

 Next, the operation will be described.

To operate this switch, the first
A high frequency of frequency F is applied to the piezoelectric element 20. Elastic body
The shape and material of 11 are selected so as to resonate at the frequency F, and resonate at the frequency F, and a standing wave is generated in the elastic body 11. The second piezoelectric element 30 for ultrasonic wave detection detects a standing wave and outputs a high frequency of frequency F.

This state corresponds to the ON state, and in order to turn it into the OFF state, the finger A, which is an operation member for operating a switch composed of a material that absorbs ultrasonic vibration, touches the operation portion 12 of the elastic body 11. By applying a weight and bringing them into close contact, it becomes difficult for the ultrasonic vibration generated by the first piezoelectric element 20 for ultrasonic wave to be transmitted to the second piezoelectric element 30 for ultrasonic wave detection.

At this time, due to the weight applied to the elastic body 11 from the switch operating finger A, the magnitude of vibration of the elastic body 11 is different, and the second piezoelectric element 30 for ultrasonic wave detection is in accordance with the magnitude of vibration of the elastic body 11. Output voltage.

Therefore, the output from the second piezoelectric element 30 for ultrasonic wave detection becomes small, and the switch operation can be performed due to the level difference caused thereby. Then, the amount of weight applied to the elastic body 11 by the finger A, which is the operation member for the switch operation,
Since the output voltage of this switch can be controlled, it is possible to use a so-called analog switch that outputs without a contact at a level according to the operation input.

As shown in FIG. 3, when a certain pressure a is applied to the switch control element 10 from the outside, a high frequency signal b (see FIG. 6A) having an amplitude corresponding to the pressure a is output from the switch control element 10. This high frequency signal b is inverted by using the inverting amplifier 15 and a high frequency signal b '(see FIG. 6 (b)) is output. The high frequency signal b'is input to the signal converter 41 which converts the magnitude of the amplitude of the high frequency signal into a DC voltage value c (see FIG. 6 (c)). The signal c converted to DC by the signal converter 41 is input to the delay circuit 42 and the reset / hold signal generator 43, respectively.

In the reset / hold signal generator 43, the input signal c is
The signal g (see FIG. 6 (e)) differentiated by the differentiating circuit 46 composed of the capacitor C1, the resistor R1, and the operational amplifier 45, and the set value and the magnitude of the variable resistors R2 and R3 are compared by the comparator 47. Compared and reset hold when the relationship between R2 setting condition r2 (voltage value Vh, rising edge detection value) and R3 setting condition r3 (voltage value Ve, falling edge) and signal g is g> r2 or g <r3 A pulse d (see FIG. 6 (f)) is generated.

The signal f (see FIG. 6D) delayed in time from the delay circuit 42 and the reset hold pulse d are input to the signal holding unit 44.

In the signal holding unit 44, the reset hold pulse d is D-
The flip-flop 48 inverts the output at the falling edge of the pulse, and when the output Q of the D-flip-flop 48 is H and the output d is H, the hold signal H is output from the NAND gates 49a and 49b.
Is output, and the inverted output Q of the D-flip-flop 48 is output.
Is H and the signal d is H, the reset signal R is output.

Here, the signal f is always transmitted with a delay of a certain time t, so that the data before the abrupt fall is the signal holding unit.
It is held at 44 and is output as output e (see FIG. 6 (j)). The time chart of the above operation is shown in FIG.
The signals b, c, g, f, d, Q, R, H, and e of (j) are as shown.

In this way, the signal of the pressure a can be set to an arbitrary value, and the controlled object 50 is controlled as the output e corresponding to the operation input when the operation of the switch control element 10 is stopped (time t2 in FIG. 6). Therefore, when the switch A is used as a dimming switch, the finger A to the operation unit 12 of the elastic body 11 of the switch control element 10 is used.
By changing the contact pressure of, it is possible to obtain an output e at a level corresponding to the contact pressure, and it is possible to adjust the intensity of illumination.

Although the elastic body 11 of the switch control element 10 is restrained by the contact pressure, the contact pressure may be changed as a result of the change of the load or the change of the contact area.

According to the switch control element according to the present embodiment, without contact, it is possible to continuously input the analog amount, it is possible to obtain a corresponding analog output to control the control target,
The operation is also reliable. Also, if it is used for a pressure sensor,
Compared with the conventional pressure sensitive sensor, it is possible to perform measurement with considerably high accuracy.

According to the present invention, the output level of the switch can be controlled in an analog manner by the analog change in the operating pressure applied to the elastic body, and therefore, there is an effect that delicate control can be performed on the controlled object. .

[Brief description of drawings]

1 to 6 show an embodiment of the present invention.
FIG. 4 is a front view of a switch control element, FIG. 2 is a perspective view of the same, FIG. 3 is a block diagram of a dimming control circuit, FIG. 4 is a block diagram of a reset / hold signal generation unit, and FIG. 5 is a signal holding unit. FIG. 6, FIG. 6 is a time chart, and FIG. 7 is a block diagram of a conventional example. 10 …… Switch control element, 11 …… Elastic body 15 …… Inversion amplifier, 20 …… First piezoelectric element 30 …… Second piezoelectric element, 40 …… Dimming control circuit 41 …… Signal converter, 42 ...... Delay circuit 43 ...... Hold signal generator 44 ...... Signal holder, 50 ...... Control target

Continuation of the front page (56) Reference JP-A-53-121675 (JP, A) JP-A-55-157814 (JP, A) JP-A-56-40710 (JP, A) Actual development Sho-53-157303 (JP , U)

Claims (1)

[Claims] 1. An elastic body which is a member to be operated and to which an operation pressure is applied, and an elastic body which is joined to a first position of the elastic body and generates ultrasonic vibration when a predetermined AC signal is applied. And a piezoelectric element connected to a second position of the elastic body spaced apart from the first position, and after being generated by the first piezoelectric element,
A second piezoelectric element that generates a voltage according to the magnitude of ultrasonic vibrations changed by the operating pressure applied to the elastic body, and an output level of the switch based on the voltage generated from the second piezoelectric element An analog switch having a control circuit for controlling