JPS5815891B2 - Sweet Chikikou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a switch mechanism for signal input in small electronic equipment.

In order to implement the present invention, a switch that is extremely compact and has a simple structure is required.

Conventional switches require special consideration for miniaturization in terms of contact structure, spring action, etc., and have many problems in manufacturing.

An object of the present invention is to provide a simple switch structure suitable for small electronic equipment.

The following will be explained based on the drawings: Figures 1, 2, and 3.
Both figures are examples based on the present invention.

In FIG. 1a, one or more common electrodes are located in the vicinity of each switch electrode, only a portion of which is shown.

The common electrode 1 and the switch electrode 2 exposed on the surface of the insulating substrate 3 are electrically connected to the wiring copper plates 5 and 4 on the back surface of the substrate, respectively.

When a part 6 of the human body touches the common electrode 1 and the switch electrode 2 at the same time, the electrodes 1 and 2 become electrically connected through the human body.

FIG. 1 shows an example in which a switch electrode 2 is provided near a common electrode 1, and nine switch groups are shown in the figure.

In this switch mechanism, after wiring the common electrode 1, the common electrode lead wire 5, the switch electrode 2, the switch electrode lead wire 4, etc. on a substrate 101 so that they do not touch each other, the coating layer 102 is treated with resin or insulation. It is made of metal that has undergone a process.

In this configuration, an insulating film is formed at the intersection of the lead wire 401 coming out from the switch electrode 201 and the lead wire 5 to avoid contact with each other, or the lead wire of the common electrode and the lead wire of the switch electrode are formed in two layers. It can also be made by forming.

Fig. 1 C is also similar to Fig. 1. Here, unlike Fig. 1, the common electrode 1 and the switch electrode 2 are each formed in a spiral shape, so that there is no leakage when touching with a fingertip. That's the idea.

All of these can be connected to the common electrode 1 simply by touching the fingertip.
It is extremely convenient because the wiring is configured so that the switch electrode 2 and the switch electrode 2 are electrically connected to each other.

In FIG. 2, the switch electrode groups 2a, 2b, 2c and the common electrode 1 are located at separate positions, and the common human body parts 6a and 6b are simultaneously connected to the switch electrode 2a and the common electrode 1, respectively.
By touching the switch electrode 6b and the common electrode 1, the switch electrode 6b and the common electrode 1 become electrically connected through the human body.

Although the common electrode is not shown in FIG. 3, it is assumed that it is electrically connected to a part 6 of the human body outside the figure through the human body.

Part 6 of the human body comes into contact with switch electrode 2 via conductive operating member 7 .

The switch electrode 2 and the common electrode 1 are electrically connected via the operating member 7 and the human body.

In either case, there is some resistance because the conduction is through the human body.

This resistance value varies depending on the contact area between the human body and the electrode, the contact pressure, the condition of the skin, etc., but usually ranges from several tens of OKΩ to several MΩ.

FIG. 4 shows a circuit embodiment of the present invention, in which the switch electrode 2 is connected to a node A, which is connected to the input terminal of an inverter 8 and connected to the high potential side of the power supply via a resistor 9. I'm there.

The common electrode 1 is connected to the low potential side of the power supply.

Normally, when the switch electrode 2 and the common electrode 1 are separated, the potential of the node A is maintained at a high potential by the resistor 9.
The output potential of the inverter 8 is at a low level (hereinafter abbreviated as "L").

Next, when the switch electrode 2 and the common electrode 1 are connected by the resistance 10 of the human body, the potential of the node A becomes a voltage divided by the resistor 9 and the resistor 10. The potential of node A becomes lower than the threshold voltage of inverter 8, and the output of inverter 8 becomes a high level (hereinafter abbreviated as "H").

Therefore, at the output of inverter 8, the switch is on,
The off state can be clearly identified.

FIG. 5 is an equivalent circuit diagram between two points on the human body when viewed from an AC perspective, and there is a capacitance C in addition to the DC resistance.

FIG. 6 shows another embodiment of the present invention in which the capacitance C is taken into account.

12 is a latch circuit, and when the clock input φ2 is "H", the state of the data input terminal appears as it is at the output Q, and φ2 is "L".
”, the state of the data input terminal immediately before φ2 changes from “H” to “L” is maintained as it is.

The data input terminal C1 of the latch circuit 12 is connected to the switch electrode 2.
The clock φ1 is applied via the resistor 11.

Common electrode 1 is connected to "L". Clock φ1 is in phase with clock φ2, and has a slightly wider pulse width than φ2.

FIG. 7 shows operating waveforms.

When there is no human body between the switch electrode 2 and the common electrode 1, the clock φ appears as it is at the node C1.

Therefore, the level at the node C1 immediately before the clock φ2 changes from "H" to L is always "H", and the latch output Q maintains "H".

Next, when a human body is interposed between the switch electrode 2 and the common electrode 1, the human body is represented by a circuit as shown in FIG.
Due to this capacitance of the human body and mainly the resistance 11, the node C1
The waveform is integrated and then discharged by the capacitor C, resulting in a rounded waveform as shown in FIG.

The resistor R is set so that the peak value of this rounded waveform does not exceed the threshold of the latch circuit 12, or even if it exceeds the threshold, the pulse of the clock φ2 can be read by the clock φ2 before it is integrated. The width is made sufficiently small so that the output of the latch circuit 12 is in the L'' state as a logic level.

Therefore, the latch output Q maintains "L".

In this embodiment, extremely accurate operation was confirmed when the value of the resistor 11 was 50 Ω and the pulse width of the clock φ1 was 10 μs or less.

Here, for the resistor 11, the clock φ1 is a complementary MOS
When the power is supplied through the channel resistance of the transistor, it can be replaced by the channel resistance and there is no need to provide a separate resistor, which is convenient in terms of manufacturing.

Also, regarding the relationship between clock φ1 and clock φ2, see the eighth section.
The circuit shown in the figure can be considered.

That is, the node E is connected to the input terminal of the inverter 13, and the two-man power NOR gate 16 and the two-man power NOR gate 1
6, each of which is connected in common to one input terminal of each of the NA
The remaining input terminals of each of the ND gate 15 and the NOR gate 16 are commonly connected to the output F of the inverter 14, and the input terminal of the inverter 14 is connected to the inverter 13.
connected to the output of

Assuming that the output of the inverter and gate appears with a time delay of τ with respect to the input, when an "L" pulse is applied to node E, F, G.

The waveform at each point of H is as shown in the figure, and the relationship between G and H is the relationship between φ1 and φ2.

As described above, according to the present invention, the switch function can be realized with an extremely simple structure.

Conventional touch switch detection methods include resistance changes and capacitance changes.Resistance methods have problems in use because they change due to dirt, while methods that use capacitance have until now detected by changes in frequency. However, this method was complicated and required circuitry.

Therefore, in this application, we adopted a method of detecting human errors by detecting the rounding of the waveform, and were able to realize a highly practical circuit with a simple circuit.

This is ideal as an input switch for small electronic devices such as wristwatches.

Note that in the embodiment shown regarding the electrode structure, the electrode and the wiring portion are different, but of course they may be located on the same side of the substrate.

In particular, if the electrodes are formed using a transparent Nesa film or the like, the characters written on the opposite side of the substrate can be seen, which is more convenient since the space for writing the type of switch can be omitted.

Furthermore, if the case of the device is used as a common electrode, when the device is held in one hand or worn on the arm, the common electrode will naturally come into contact with the human body, which is more convenient for operation.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are embodiments of a switch mechanism according to the present invention, FIG. 4 is an embodiment of the circuit diagrams of the embodiments shown in FIGS. 1 to 3, and FIG. is an equivalent circuit diagram between two points on the human body when viewed from an AC perspective, FIG. 6 is an example of a circuit diagram of a switch according to the present invention considered based on FIG.
6 is a waveform diagram of the circuit diagram of FIG. 6, and FIG. 8 is a waveform diagram of the circuit diagram of FIG. 6. 1 is an example diagram of a circuit and waveform diagram for producing a φ2 signal; FIG. 1... Common electrode, 2... Switch electrode, 4, 5... Wiring copper plate, 12... Latch circuit.

Claims (1)

[Claims] 1. By bringing the switch electrode and the common electrode into contact with the human body directly or via a conductive operating member,
In a switch mechanism in which the two electrodes are electrically connected through the human body, a means for periodically applying a pulse to the switch electrode via a resistance component, and reading the state of the switch electrode during application of the pulse. When the two electrodes are brought into conduction by the human body, the pulse is rounded due to the integral action of the capacitance of the human body and the resistance.
A switch mechanism characterized in that the output of the latch means is configured to indicate a state different from normal, and a conduction state between the two electrodes is detected.