JPS62147613A - input device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an input device using a capacitance method used in various types of equipment.

Conventional technology Traditionally, input devices that use capacitance as touch switches use dielectric materials such as tempered glass for the inlet panel, making it easy to create a structure that prevents the intrusion of dust and water droplets. It is becoming more and more popular because it improves reliability.

An input device using this type of capacitance method has an input section consisting of a touch panel that the user touches to make input settings, and an electrode placed on the back of the touch panel that detects whether or not the user is touching the panel. It consists of a control section that performs predetermined control based on signals from the input section, and the input section and the control section are connected by signal lines printed together with electrodes and the like on a flexible wiring board. To reduce the influence of adjacent signal lines on the flexible wiring board,
The influence of adjacent signal lines is alleviated by widening the spacing between signal lines as much as possible and by providing shield lines with a certain potential between the signal lines.

Hereinafter, a conventional input device using a capacitance method will be explained with reference to the drawings.

Figure 3 is a view from the back, where 1 is a flat panel made of a dielectric material such as tempered glass, 2 is a flexible printed circuit board whose base material is an insulator, 3 is a drive electrode, 4 is a detection plate, 5 6 is a detection signal line, 6 is a shield line, 7 is a drive signal line, 8 is a drive power source, and 9 is a control circuit. A detection electrode 4, a detection signal @6, a shield line 6, and a drive signal line 7 are configured on the flexible printed wiring board 2. It is connected to the drive power source 8.

The operation of the input device configured as above will be explained. First, when the user touches a predetermined location on the flat panel 1 with his or her finger, the capacitance with the ground changes, and the outputs of the drive power source 8, drive signal line 7, and drive electrode 3 are transferred to the ground via the user. The change in the signal at that time is detected by the sensing electrode 4.
is induced and input to the control circuit 9 via the detection signal line 5, and the user's settings are accepted by this five human power signals. At this time, since a shielded wire 6 with one end connected to ground is provided between each detection signal line, even if there is a change in the detection signal level due to the user's touch, there is no effect on the adjacent detection signal line 5. ease.

In addition, in order to alleviate the influence of adjacent detection signal lines 5 without using solder@6, there is a method of widening the interval between adjacent detection signal lines 5 and reducing stray capacitance between adjacent detection signal lines. Often used.

Problems to be Solved by the Invention The shield wire 6 is connected to the adjacent detection signal wire 5 in FIG.
Although the method of providing a detection signal can improve the influence on the signal on the adjacent detection signal @ 6 due to a change in the detection signal, it always causes leakage current through the stray capacitance between the detection signal line 6 and the shielded line 6. Because of the flow, the detection sensitivity width (the difference between the potential when the user touches it and the potential when the user does not touch it) becomes small.

Furthermore, a space is required to arrange the shield wire 6 between the detection signals @5, and the narrower the distance between the detection signal wire 5 and the shield wire, the narrower the detection sensitivity width becomes.

On the other hand, the adjacent detection signal line 6 without using the shield line 6
Although increasing the distance between is one of the effective ways to reduce leakage current flowing through stray capacitance,
A certain amount of space is required to provide sufficient spacing between the detection signal lines 5, and if there is a space restriction, it may be difficult to reduce stray capacitance.

The present invention has been made to solve these problems, and eliminates the need to use shielded wires 6, and eliminates stray capacitance between detection signal lines 6 without changing the spacing between adjacent detection signal lines 5. By reducing this, the influence of the signal on the adjacent detection signal line 5 can be alleviated, and as a result, it is possible to provide an input device with an improved detection sensitivity range.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a flexible printed wiring board in which cutouts are provided at predetermined portions of adjacent signal lines such as detection signal lines, and a flat plate made of a dielectric material. This configuration constitutes an input device.

Effect By adopting the above-mentioned configuration and providing a notch between the signal lines, the capacitor generated between the signal lines is separated from the capacitor whose dielectric is the base material (for example, polyester) of the flexible printed wiring board by air It is almost equivalent to a capacitor whose dielectric is , and its stray capacitance is
(Dielectric constant of air/dielectric constant of base material of flexible wiring board).In other words, it is equivalent to increasing the distance between the signal lines without changing the interval between the signal lines.

Therefore, stray capacitance is reduced, the effects of changes in signal levels on adjacent signal lines are alleviated, and users do not have to touch them (
The difference between the signal level generated when the user touches (no touch) and the signal generated when the user touches (touch) (detection sensitivity width) V spreads by the amount that is not affected by changes in the signal level, and can be applied to multiple input keys. The design of the input device also becomes easier, and the user's settings can be made more reliably, making it possible to improve the usability and reliability of the input device.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a detailed view of a flat panel of an input device according to an embodiment of the present invention, as seen from the back side.

In Fig. 1, 1 is a flat panel panel made of a dielectric material such as tempered glass, 2 is a flexible printed wiring board whose base material is an insulator such as polyester, 3 is a drive electrode, 4 is a detection electrode, and 5 is a detection signal. The line 6a is a cutout portion obtained by cutting out a predetermined portion of the flexible printed wiring board 2, 7 is a drive signal line, 8 is a drive power source that supplies an alternating current or pulsed voltage, and 9 is a control circuit. , the detection electrode 4, the detection signal line 5, and the drive signal line 7 are constructed on a flexible printed wiring board. Drive power supply 8? i and the drive signal line 7, and the detection signal line 5 is connected to the control circuit 9. The cutout portion 6a is provided so as to leave a portion of the base material of the flexible printed wiring board so that the detection signal lines 5 maintain a certain interval.

FIG. 2 shows a circuit including two adjacent detection signal lines in the configuration of FIG. 1. Here, C11°C12,C
21, C2□ is the capacitance determined by the drive electrode 3 and the detection electrode 4, C8 is the stray capacitance generated between the detection signal lines 50, and 1. v2 is a potential induced in each of the sensing electrodes, and 91.92 is an input terminal to the control circuit 9.

The operation of the input device configured as described above will be described below with reference to FIGS. 1 and 2. C11,
The capacitance of C12, C21, C22 is usually 5 to 1oPF
The capacitance C0 of the human body is on the order of 10
It is on the order of o~200PF.

Therefore, if the user does not touch the specified position of the flat panel (grave 1 in this example),
v is approximately determined by the combined capacitance of each capacitance C11°1 2 C12 and C21, C22. In other words, it can be safely assumed that almost no leakage current flows through the stray capacitance C8.

On the other hand, if the user touches (touches) a predetermined position, it will be bypassed to the earth (capacitance C6 = 1oO~2oOPF) through the user, and the air dielectric sensing electrode 6
As a result, a leakage current flows to the stray capacitance C8, and the potential 2 of the sensing electrode S of the permittivity of the base material of the flexible wiring board changes to the voltage of the sensing electrode 5 of the air dielectric. It depends on the potential v1, and now if the impedance of the stray capacitance C8 is Zs, the potential of the sensing electrode 5 of the dielectric constant of the base material of the flexible wiring board (the potential of the input terminal 92)
v2 becomes y v.

2-Zs+R2 From the above formula, if impedance ZS approaches infinity,
v2 becomes less susceptible to the influence of vl. (Tsamari■2;φ
becomes. ) On the other hand, since the impedance of the capacitor is Zs=-, where f is the frequency of the power supply, C8 should be brought close to φ in order to bring j2πfC8 zs close to infinity. Therefore, the stray capacitance C8 reduces the distance between the signal lines by d,
If the area at that time is S and flexible pudding, then C3
It is indicated by =-1-.

Therefore, by providing the notch 6a between adjacent detection signal lines 5, the dielectric between the detection signal lines 5 can be made of air, and as a result, the stray capacitance can be reduced without changing the distance between the detection signal lines 5. The capacitance of C8 can be set to (permittivity of air/permittivity of base material of flexible printed wiring board).

Note that in this embodiment, a notch 6a is provided between the detection signal lines 5.
However, a cutout 6a may be provided between the drive signal line 7 and the detection signal line 6. In other words, the cutout may be provided at a location where it is desired to alleviate the influence of stray capacitance.

Effects of the Invention As described above, the present invention comprises a plurality of pairs on a flexible printed wiring board consisting of a drive electrode, a drive signal line connected thereto, a detection electrode and a detection signal line connected thereto, and a drive signal line and a detection signal line connected thereto. A notch is provided at a predetermined portion between the signal line or adjacent detection signal line, and the flexible printed wiring board is provided on the back side of a flat panel made of dielectric material. By providing cutouts in predetermined portions, it is possible to reduce stray capacitance without changing the spacing between each signal line, and as a result, the effects of signal level changes on adjacent signal lines are alleviated, making it easier to use. The difference between the signal level that occurs when the user does not touch it and the signal level that occurs when the user touches it (detection sensitivity width) increases by the amount that is not affected, making it possible to design even input devices with multiple input keys. This makes it easier and allows the user to make settings more reliably.
The effect is great.

[Brief explanation of drawings]

FIG. 1 is a plan view of a flat panel of an input device showing an embodiment of the present invention, seen from the back side, FIG. 2 is an equivalent circuit diagram of an input device using the same flat panel, and FIG. , is a plan view of a flat panel of a conventional input device, viewed from the back side. DESCRIPTION OF SYMBOLS 1...Flat panel, 2...Flexible printed circuit board, 3...Drive electrode, 4
...Detection electrode, 6...Detection signal line, 6
a: Notch portion, 7: Drive signal line. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
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Claims (1)

[Claims] The drive signal line and the detection signal line on a flexible printed wiring board on which a drive electrode and a drive signal line connected thereto, and a detection electrode opposite to the drive electrode and a detection signal line connected thereto are formed. An input device, wherein a notch is provided at a predetermined portion between the detection signal lines, and the flexible printed wiring board is provided on the back side of a flat panel made of a dielectric material.