JPH0482414A - Non-touch switching device - Google Patents

Abstract

PURPOSE:To hold the brightness of a display element by performing the key scan of a non-touch key on another column or row by a control means when the display element is scanned at every column or row. CONSTITUTION:Each column is scanned as a dynamic lighting system, and the on/off of a light emitting diode is controlled in a row direction. The key scan of another column is performed simultaneously when a first column is scanned. Threshold levels when the light emitting diode is turned on/off are stored, respectively, and the key scan is performed corresponding to the state of each row. By executing the control and the key control of the light emitting diode by performing such scan on each column repeatedly sequentially, wasteful time can be eliminated, and the light emitting diode can be lit brightly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a non-touch switch device that uses a flat capacitor and detects a change in capacitance of the flat capacitor.

[Prior Art] The basic patent for this type of non-touch switch is owned by InchLeft Electronics Limited of Australia. The patent number is PCT/^U36
It is 100043.

Next, the configuration and basic operation of this non-touch switch will be explained. As shown in Figure 3, outside 1! I [r board 2
and a central electrode plate 4 disposed inside the outer electrode plate 2 with an insulator 3 interposed therebetween, which is indicated by diagonal lines. As shown in FIG.
A square wave is input as a drive signal to the center plate 4, and a detection transistor Q+ is connected to the center plate 4.

FIG. 6(a) shows the charge distribution state of a flat plate capacitor, and FIG. 6(b) shows the charge distribution state when a fingertip approaches the capacitor. That is, when a 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 center electrode plate 4, there is a capacitor between the outer electrode plate 2 and the fingertip, and the center electrode. 4 and a capacitor between the fingertip will be formed. Therefore, the charge between the electrodes is divided, and the output waveform shown in FIG. 5(a), which is not brought close to the normal fingertip, is changed from the current flowing through the transistor Q, as shown in FIG. 5(b), to the output pulse. changes. This change is detected to determine whether the non-touch switch 1 is on or off. Such individual non-touch switches 1 are arranged in a matrix as shown in FIG.

[Problems to be Solved by the Invention] In such a conventional example, as shown in FIG. A hole 6 is provided, and a light emitting diode 7 is placed within this hole 6. The anode of the light emitting diode 7 is connected to a power source via a current control resistor r, and the cathode is grounded via a switch SW so that the light emitting diode 7 is turned on.

By the way, FIG. 9 shows a block diagram showing the signal system of the non-touch switch 1. As shown in FIG.

Although only one non-touch switch 1 is shown, they are formed in a matrix. A square wave key scan drive signal is key scanned and inputted to each non-touch switch 1 from the arithmetic control circuit 10 made up of a microcomputer as described above. and,
The output of the non-touch switch 1 is detected by a transistor Q, and the DC component of the output of the transistor Q1 is removed by a DC component removal circuit 11. Then, the output signal amplified by the amplifier circuit 12 is held at its peak by the peak hold circuit 13, further compared with the threshold level which is the reference value from the arithmetic control circuit 10 by the comparator 14, and the output is inputted to the arithmetic control circuit 10. are doing. t
Furthermore, the light emitting diode 7 is controlled by an on/off control signal in response to the output of the comparator 14 by the arithmetic control circuit 10, and furthermore, the light emitting diode 7 is dynamically illuminated by an LED scan signal.

When controlling the light emitting diode 7 dynamically in consideration of current consumption, if processing is performed in series with the key scan as shown in FIG. There is a problem that 7 becomes dark.

The present invention has been provided in view of the above-mentioned points, and provides a non-touch switch device for the purpose of brightly lighting up the display elements when five display elements are dynamically lit.

[Means for Solving the Problems] The present invention includes a control means for key-scanning non-touch switches in other columns or rows when display elements are being scanned column by column or row by column.

[Function] Thus, when the display elements are scanned column by column or row by row, the control means performs key scanning of non-touch switches in other columns or rows.

[Example] Hereinafter, embodiments of the present invention will be described with reference to the drawings.In the present invention, instead of the conventional method of processing the lighting control of the light emitting diode and the key control of the non-touch switch in series, the present invention uses a method in which the light emitting diodes are arranged in a row. When each column (or row) is dynamically lit, key control is performed for columns (or rows) that are not being scanned.

The second rM shows a conceptual diagram, and as shown in the same rz<b>,
In non-touch switches arranged in a matrix, if the first row is scanned with light emitting diodes as shown in FIG. When the second row is scanned with light emitting diodes, the other rows are key scanned, and so on. N(b) shows the case where light emitting diode scanning is performed in the fourth column and key scanning is executed in the other columns.

Next, a detailed explanation will be given with reference to FIG. Here, 4×
I will explain using the key matrix of 4. As a dynamic lighting method, each column is scanned and the on/off of the light emitting diodes is controlled from the row direction. While scanning the first column, key scan the remaining 2 to 4 columns at the same time. At this time, since each row is controlled by the on/off state of the first column, if key scans are performed at the same threshold level, variations in sensitivity will occur. Therefore, threshold levels are set for when the light emitting diode is on and when the light emitting diode is off, and key scanning is performed according to the state of each row. This is generally the same for mXn key matrices.

Note that the shaded area in Figure 1 indicates that the threshold level when the light emitting diode is off is used, and the other areas other than the shaded area indicate that the threshold level when the light emitting diode is on is used. It shows that there is.

Scan the above in the 2nd column, 3rd column, etc.
By repeating this, by executing the light emitting diode control and key control in parallel, wasted time can be eliminated and the light emitting diode can be lit more brightly than in the conventional method.

Also, if there are many non-touch switches and key scanning takes time and the lighting cycle of the light emitting diodes becomes long, it is sufficient to key scan only the row next to the one where the light emitting diodes are being scanned instead of key scanning all of them.

[Effects of the Invention] As described above, the present invention includes a control means for key-scanning non-touch switches in other columns or rows when display elements are scanned column by column or row by column. When the control means scans the display elements column by column or line by line, key scanning of non-touch switches in other columns or rows allows display element control and key control to be executed in parallel, reducing waste. Eliminate the time,
This has the effect that the display element can be lit more brightly than the conventional method.

[Brief explanation of the drawing]

1st [! I is a detailed explanatory diagram of the present invention, Fig. 2 is an explanatory diagram of the same as above, Fig. 3 is a plan view of the non-touch switch, Fig. 4 is a circuit diagram of the same as above, and Figs. 5 (a) and (b) are respectively the same as above. 6(a) and 6(b) are explanatory diagrams of the same as above, FIG. 7 is a plan view showing the non-touch switches arranged in a matrix, and FIG. 8 is a diagram of the conventional example. FIG. 9 is an overall circuit diagram, and FIG. 10 is an explanatory diagram of a conventional system. 1 is a non-touch switch. Figure 3 Figure 4 Agent Patent Attorney Ishi 1) Chief 7 Figure 5 (b) Figure 6 Figure 1N7 Figure 8

Claims (1)

[Claims] (1) Non-touch switches that detect changes in the capacitance of flat capacitors are arranged in a matrix, each non-touch switch is equipped with a display element that displays the on/off state, and each non-touch switch is scanned with a key at regular intervals. This signal is input as an output pulse as a change in the capacitance of the flat capacitor due to the approach of the fingertip, and the display element of the corresponding non-touch switch is dynamically illuminated in response to the output pulse. A non-touch switch device, characterized in that the switch device comprises a control means for key-scanning non-touch switches in other columns or rows when display elements are scanned column by column or row by row.