JPS5849893B2 - key input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a key manual device used in desktop electronic computers and the like.

In general, when a desk computer or an electronic wristwatch with calculation function is equipped with many keys and requires miniaturization, the key is pressed like a conventional keyboard method, and the difference in stroke is used to manually press the key. From the viewpoint of miniaturization and thinning, controlling the on/off state of the device is subject to limitations.

In addition, there are devices that use touch-type switches as keys to configure key-powered devices, but this method requires touch-type switches in one-to-one correspondence with numeric keys or function keys. If there are a large number of LSIs, there is a disadvantage that the number of external components and input lines to the LSI increases, and there remains a problem in terms of miniaturization and thinning.

The structure of the former keyboard, that is, a key-operated device, is shown in FIG. 1, which shows the key-operated section of an electronic watch with a calculator.

A matrix 1 is composed of a column line dm and a row line km, and a mechanical switch S as shown in FIG. 2 is installed at each intersection.
These switches S and each wiring constitute a key human power device.

For example, when a key is pressed, the switch S of the key is closed, the column line d3 and the row line k2 are connected, and a timing signal is received from the drive-in D3 which is the signal derivation terminal of the LSI element, that is, the electronic wristwatch circuit with calculator 2. By transmitting the signal to line k2, it is detected that the key ■ has been pressed.

In addition, 2 in the figure is a circuit of an electronic watch with a calculator, for example,
If the electronic watch is now set to calculation mode, when the above-mentioned key is pressed, the number V"7" will be displayed on the display section 2 via the circuit 2.

As mentioned above, in a manual key device like the one shown in Figure 1, keys are pressed and the key is turned on and off by the difference in stroke. , it is clear that there are restrictions when thinness is required.

Next, a method using a touch switch will be explained.

FIG. 3 shows the signal detection circuit of the touch switch.

Normally, when the watch case and the touch electrode 3 are not connected due to the human body resistance R3, the gate input of the C-MOS inverter is pulled to the power supply voltage +■ by the pull-up resistor R1 and the protective resistor R2.

At this time, since the gate of the C-MOS inverter)1 is the logical value "1'", the output signal of the touch signal detection circuit ?4, which is the output of the C-MOS inverter, is the logical value uO tt.
It is.

Next, the human body resistance R3 is connected, that is, when the fingertip of the human body touches the touch electrode 3 and the watch case (earth), the human body resistance R3 is connected between the earth (GND) and the power supply voltage +VDD.
and a pull-up resistor R1 are constructed, and the divided voltage thereof is applied to the gate input of the C-MOS inverter.

When this partial voltage exceeds the threshold voltage, the C-MOS inverter reverses its state, and the output signal of the touch signal detection circuit 4 becomes a logical value "1", thereby detecting the touch of the human body.

Further, the capacitor C constitutes a filter circuit together with the pull-up resistor R1 and the protective resistor R2, and removes external noise.

FIG. 4 shows an example of a case where the touch signal detection circuit 4 is used to implement a key manual device using a touch type switch.

A touch electrode is provided for each of the number keys and function keys, and the husband's touch electrode DB...
Lotus corresponds to the touch signal detection circuit T explained in FIG. 3 in one-to-one correspondence.

, T1...... are connected to Tc.

Also, this touch signal detection circuit T.

, T1 . . . The outputs of Tc are input to the signal conversion circuit 7.

That is, the signal conversion circuit 7 includes each AND gate A.

, A1...The touch signal detection circuit T is connected to one input terminal of Ac.

, T1...Tc is added to this touch signal detection circuit T.

, T1... If Tc outputs the logical value "'1", the AND gate A corresponding thereto.

, A1...Ac is in an open state, and the timing signal from the drive-in Dm is transmitted to the receive line Km.

Now, if there is no input at all to the touch electrode group 5, that is, if the touch electrode is not touched with a finger or the like, all outputs of the touch detection circuit group 6 will have a logic value of ``0'' as explained in FIG.
”.

In this case, since one input of all the AND gates of the signal conversion circuit 7 is the logical value e+O $1, the signals from the drive lines D1 to D5 are completely transferred to the receive line K1.
~K4 is not informed.

On the other hand, for example, when the touch electrode is touched, the output of the touch signal detection circuit T7 becomes a logical value "1", and the AND gate A7 opens and the signal of the drive-in D3 is transferred to the receive line K.
2 is input via OR gate 0, and "7" is input.

As described above, the C-MOS inverter and signal conversion circuit 7 of the touch signal detection circuit group 5 are connected to the electronic wristwatch circuit 2 with a calculator.
However, in the conventional method as shown in Figure 4, external components such as pre-up resistor R1, protection resistor R2, and capacitor C are required as many as the number of keys. The number of input/output lines increases, which is disadvantageous in terms of miniaturization and thinning.

SUMMARY OF THE INVENTION Accordingly, the present invention aims to eliminate the disadvantages of using touch-type switches by configuring keys and matrices using touch-type switches.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 5 shows an embodiment of the invention. column line d
m and row lines Kn are arranged in a matrix, and a touch switch T-Smn corresponding to each key as shown in FIG. 6 is provided at each intersection.

This touch type switch T-Smn has a structure in which the touch electrode 11 on the row line Kn side and the touch electrode 12 on the column line dm side can be simultaneously touched by a fingertip.

Further, touch signal detection circuits Tkn and TDm as shown in FIG. γ are connected to each line Kn and dm, respectively.

For example, when a fingertip touches the key located at the intersection of the row line kn and the column line dm, that is, the touch switch T S m n, the touch electrodes 11 and 12 are simultaneously connected to each other due to human body resistance, resulting in a circuit as shown in FIG. Become.

As is clear from this, the touch electrode 12 of the column line dm and the touch electrode 11 of the row line kn are simultaneously connected to the watch case (GND) by the human body resistances R3Dm and R3km.
As explained in FIG. 3, the output signals of the touch signal detection circuits TI)m and Tkm both have a logical value of "1".

Furthermore, when a fingertip touches the touch switch T-Smn, a human body resistance R3mn occurs between both touch electrodes 11 and 12.
is in a connected state, and this human body resistance R3mn does not work against the operation of the touch switch.

This is because human resistance R3kn = R3Dm, and if pull-up resistance R1kn = RI Dm, the potential is the same as that of the touch electrode 11, and the human resistance R between this
No current flows through R3mn, and there is no influence of this human body resistance R3mn.

Also, human body resistance R3kn, R3Dm and pull-up resistance R1
If kn, R1Dm vary, the human body resistance R3 of the fingertip
Although current flows through mn, it only serves to reduce the potential difference between the touch electrodes 11 and 12, and does not have any adverse effect on the operation of the touch switch.

On the other hand, the output of the touch signal detection circuit group 9 is
It is entered as 0.

This signal conversion circuit 10 is for obtaining a signal from the touch signal detection circuit group 6 shown in FIG. It is configured by adding the outputs of the circuits Tk1 to Tk4 and adding the outputs of the touch signal detection circuits Td1 to Td5 connected to the column lines d1 to d5 to the other input terminals.

The output from the signal conversion circuit 10 is applied to the signal conversion circuit 7 described in FIG. 4, where similar signal processing is performed.

Next, the operation of the key manpower device shown in FIG. 5 will be explained.

For example, when a fingertip or the like touches a key or touch-type switch located at the intersection of row line k2 and column line d3, the outputs of touch signal detection circuits Tk2 and Td3 both change to a logical value u 1j
It becomes l.

At this time, only the AND gate AG7 of the signal conversion circuit 10 derives an output having the logical value ++I n.

The outputs of all other AND gates are logical values n O tt.

This output signal is passed through the signal conversion circuit 7, and it is determined that the timing signal from the drive line D3 is input to the receive line K2, and that the key "7" has been input.

Thereafter, calculation processing and the like are performed in the electronic wristwatch circuit 2.

As explained above, the key human power device in the present invention is of the conventional type (as shown in Fig. 4) in terms of circuit configuration.
Although the number increases slightly, there is no problem because each C-MOS inverter of the touch signal detection circuit group 9 and the signal conversion circuits 7 and 10 are incorporated into the same LSI as the electronic wristwatch circuit 2.

In addition, in a conventional key-operated device using a touch-type switch, for example, in the example shown in FIG.
Since touch signal detection circuits are required, 17 touch signal detection circuits are required for 17 keys, and of course 17 external components such as pull-up resistors, protection resistors, and capacitors are also required.

On the other hand, the key human-powered device of the present invention requires only nine touch signal detection circuits, nine pull-up resistors, protection resistors, and capacitors, as shown in Figure 5, which significantly increases the The number of external parts can be reduced.

Furthermore, in the one shown in FIG. 4, the C-MOS inverter of the touch signal detection circuit group 5, the signal conversion circuit 7, and the electronic watch circuit with calculator 2 can be incorporated into the LSI, and this LSI requires 17 input/output lines. On the other hand, in the present invention, there are only nine, which can be reduced to a dog's width.

As described above, the key-operated device of the present invention is particularly effective for electronic devices that require a large number of keys, such as electronic wristwatches with added calculation functions. Because it is used, durability is increased, and since no stroke is required, it can be made thinner.

Additionally, compared to conventional touch-type switches, touch-type switches are installed at the intersections of each line arranged in a matrix, which greatly reduces the number of external components and LSI input/output lines. can be reduced to

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a key manual device using a conventional mechanical switch, FIG. 2 is an explanatory diagram of the switch in FIG. 1, and FIG. 3 is a circuit diagram for detecting a touch signal. FIG. 4 is a block diagram showing a key-powered device using a conventional touch-type switch, FIG. 5 is a block diagram showing a key-powered device according to the present invention, and FIG. 6 is a block diagram showing a touch-type switch according to the present invention. 7 are circuit diagrams for explaining touch signal detection according to the present invention. dm...column line, kn...row line, 11...touch electrode on the row line side, 12...
...Touch electrode on column line side, T-Smn...
・Touch type switch.

Claims (1)

[Claims] 1) A switch is provided at the intersection of each line of the row and column arranged in the shape of a square, and the switch is connected to each line of the row and column in a key-powered device configured to correspond to each key. A touch electrode is provided at the intersection, a touch signal detection circuit including a C-Mos inverter is connected corresponding to each of the rows and columns, and the outputs of the touch signal detection circuit are combined to generate a key manual signal corresponding to each key. What is claimed is: 1. A key-powered device comprising a signal conversion circuit comprising a group of gate elements for deriving .