JPH05135672A - Non-touch switch device - Google Patents

Abstract

PURPOSE:To make a non-touch switch react to an approaching conductor irrespective of the surface area of the conductor. CONSTITUTION:A non-touch switch 1 is provided with an insulating surface material 21. A conductor film 22 is installed on the upper face of the surface material 21. The conductor film 22 is equal in overall size to the non-touch switch 1. Should an approaching conductor 23 make contact with the conductor film 22 on the surface material 21, this is the same as approaching with the surface area of the conductor film 22 irrespective of the surface area of the approaching conductor 23. Therefore, amounts by which the output level of the non-touch switch 1 is decreased are almost the same, and an appropriate reference value is provided so that the non-touch switch 1 reacts to the conductor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-touch switch device which detects the on / off state of an input by detecting a change in its electrostatic capacitance using a plate capacitor.

[0002]

The basic patent for this non-touch switch is owned by Intellect Electronics Limited of Australia. Patent number is PCT
/ AU86 / 00043. Next, the configuration and basic operation of this non-touch switch will be described. As shown in FIG. 3, the non-touch switch 1 includes an outer electrode plate 2 and
An insulator 3 arranged inside the outer electrode plate 2 and shown by diagonal lines
It is formed of a flat plate capacitor composed of a central electrode plate 4 and a central electrode plate 4.

As shown in FIG. 4, a square wave is inputted to the outer plate 2 as a drive signal, and a detection transistor Q ₁ is connected to the central plate 4. FIG. 6A shows a charge distribution state of the flat plate capacitor, and FIG. 6B shows a charge distribution state when the fingertip is approached. That is, when the fingertip approaches the switch surface of the non-touch switch 1, the finger acts as a third electrode, and in addition to the capacitor between the outer electrode plate 2 and the central electrode plate 4, the electrode plate between the outer electrode plate 2 and the fingertip, the central electrode plate. 4 will be formed between the fingertip and the fingertip.

Therefore, the charge between the electrodes is divided, the electrostatic capacitance between the electrode plates 2 and 4 is reduced as compared with the normal state, and accordingly, the normal fingertip is not approached, as shown in FIG. 5 (a). As for the output waveform, as shown in FIG. 5B, the current flowing through the transistor Q ₁ decreases and the output pulse changes. This change is detected to determine whether the non-touch switch 1 is on or off.

On the other hand, to determine whether the non-touch switch 1 is turned on or off, a reference value created from the peak value of the detection pulse when the power is turned on is stored, and the peak value of the detection pulse signal is successively compared to obtain the reference value. If it is smaller than the (threshold level), the non-touch switch 1 is determined to be on. The detection pulse is taken out at a constant cycle and the comparison judgment is repeated.

FIG. 2 is a block diagram showing a signal system of the non-touch switch 1. A square-wave key scan drive signal is scanned and input to each non-touch switch 1 from the arithmetic and control circuit 10 including a microcomputer as described above. And
The output of the non-touch switch 1 is detected by the transistor Q _1, the output of the transistor Q ₁ is a direct current component is removed by the DC component removing circuit 11.

The output signal amplified by the amplifier circuit 12 is peak-held by the peak-hold circuit 13, and
The comparator 14 compares the reference value from the arithmetic control circuit 10 and inputs the output to the arithmetic control circuit 10. Also,
The light emitting diode 7 receives the output of the comparator 14 by the arithmetic control circuit 10 and is controlled by an on / off control signal,
Further, the light emitting diode 7 is dynamically turned on by an LED scan signal.

In order to clarify the on / off state of the non-touch switch 1, as shown in FIG. 3, a hole 6 is provided at the center of the central electrode plate 4 and the substrate 5 of the non-touch switch 1, and the hole 6 is provided in the hole 6. The light emitting diode 7 is arranged. Further, a plurality of non-touch switches 1 are arranged adjacent to each other in parallel to form a non-touch switch device.

[0009]

Non-touch switch 1
As described above, the determination of ON or OFF is caused by the approaching conductor (an object having a sufficiently large capacity with respect to the ground). That is, the closer the conductors are and the larger the surface area (facing the switch surface), the smaller the capacitance between the capacitors, and a large change can be detected. On the other hand, in the case of a sharp conductor or the like having a small surface area, no significant change is seen even when approaching the non-touch switch 1, and it becomes difficult to react.

The present invention has been made in view of the above points, and an object thereof is to provide a highly sensitive non-touch switch device which reacts regardless of the surface area of the approaching conductor.

[0011]

SUMMARY OF THE INVENTION The present invention uses a plate capacitor to detect a change in its capacitance and to turn on the input,
A non-touch switch for detecting off is formed, and a conductor is installed on the upper surface of the non-touch switch.

[0012]

By installing the conductor on the upper surface of the non-touch switch, regardless of the surface area of the approaching conductor,
A non-touch switch that reacts when approaching a certain distance can be configured.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. Since the entire structure is the same as the conventional one, the gist of the part will be described in detail. That is, as shown in FIG.
The non-touch switch 1 is provided with a surface material 21 made of an insulator, and the thickness of the surface material 21 is 1/2 of the outer diameter dimension 1 of the non-touch switch 1.

A conductor film 22 made of a conductor is provided on the upper surface of the surface member 21. The outer diameter of the conductor film 22 is the same as that of the non-touch switch 1.
Even if the area of the conductor film 22 is made larger than the area of the non-touch switch 1, the change amount of the output level does not change. now,
As shown in FIG. 1, when the approaching conductor 23 touches the conductor film 22 on the surface material 21, it is the same as approaching with the surface area of the conductor film 22 regardless of the surface area of the approaching conductor 23. The decrease amount of the output level of the switch 1 becomes almost the same, and it reacts by providing a proper reference value.

[0015]

As described above, the present invention forms a non-touch switch for detecting the on / off of the input by detecting the change of the electrostatic capacitance by using the plate capacitor, and the conductor is provided on the upper surface of the non-touch switch. Because it was installed,
By arranging the conductor on the upper surface of the non-touch switch, it is possible to configure a non-touch switch that reacts when approaching a certain distance regardless of the surface area of the approaching conductor.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an overall block diagram of a non-touch switch device.

FIG. 3 is a plan view of a non-touch switch.

FIG. 4 is a circuit diagram of a non-touch switch.

FIG. 5 is a diagram showing an output waveform of a non-touch switch.

FIG. 6 is an explanatory diagram of a non-touch switch.

[Explanation of symbols]

 1 Non-touch switch 21 Surface material 22 Conductor film 23 Approaching conductor

Claims (1)

[Claims] 1. A non-touch switch characterized by forming a non-touch switch for detecting an on / off state of an input by detecting a change in its capacitance using a flat plate capacitor, and disposing a conductor on an upper surface of the non-touch switch. Switch device.