JP2008078022A - Switch device with touch detection function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switch device with a touch detection function capable of performing stably touch detection of a finger on an operating member. <P>SOLUTION: In the switch device, an operating button 3 which is touched by a finger on a body 1 is installed movably, a printed-circuit board 4 having a wiring part 7 is installed on the body 1 corresponding to the operating button 3, and a switch 6 which operates based on pressing operation of the button 3 is installed on this printed-circuit board 4. Then, a touch detection electrode 8 of plate-shape is installed on the printed-circuit board 4, its projection base part 8a is connected electrically to the wiring part 7, and its top end part 8c is positioned near the surface of the side of the operating button 3 on which the finger touches. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a switch device with a touch detection function having a touch detection electrode for detecting when a finger touches an operation member.

For example, a switch device for selecting a display device that displays a plurality of selection units on a screen includes operation buttons as a plurality of operation members corresponding to the plurality of selection units, and an operation button selected by a user. A configuration is considered in which when a pressing operation is performed with a finger, a switch element disposed below the operation button operates to select and determine a corresponding selection unit in a display state.
In addition, a publicly known document corresponding to the problem to be solved by the present invention could not be found.

By the way, in the above-mentioned thing, the user needs to operate after seeing and selecting the operation button of the switch device. For this reason, the user needs to see both the operation button of the switch device and the screen of the display device, and there is a problem that the operability is not good.
Therefore, in order to cope with such a problem, the inventor considered the following. That is, when a finger touches the operation button of the switch device, this is detected, and the display state of the selection unit corresponding to the operation button is changed. According to such a configuration, since the position of the operation button in contact with the finger can be known by looking at the display screen, it is possible to operate by looking only at the display screen without looking at the operation button of the switch device. It becomes possible.

  As a switch device with a touch detection function for realizing this, the inventor considered a configuration (comparative example) shown in FIG. 7, for example. FIG. 7 is a longitudinal sectional view of the switch device with a touch detection function. The operation button 101 constituting the operation member is formed of a synthetic resin so as to form a rectangular container whose lower surface is opened, and a touch detection electrode 102 is provided on the lower surface of the operation surface portion 101a. A body 103 is arranged around the operation button 101 with a space for movement of the operation button 101 interposed therebetween.

  A printed wiring board 104 is disposed below the operation button 101, and printed wiring is provided on the printed wiring board 104. The touch detection electrode 102 is electrically connected to the wiring portion 106 of the printed wiring board 104 through an elastically deformable flexible printed wiring board (hereinafter referred to as FPC) 105 as described later. The FPC 105 has a structure in which a copper wiring portion (not shown) is sandwiched between plastic sheets, and the upper surface portion on one end side disposed on the operation surface portion 101a of the operation button 101 is touch-detected. The electrode 102 is used.

The FPC 105 is arranged along a space 101 b formed on one side surface of the operation button 101, and is fixed by press-fitting an inner case 101 c inside the operation button 101. The other end portion side of the FPC 105 is electrically connected to the wiring portion 106 on the lower surface of the printed wiring board 104.
In the printed wiring board 104, a switch 107 as a switch element is disposed at a position corresponding to the lower side of the other side surface portion 101d of the operation button 101. In this case, an interval allowing the downward movement of the operation button 101 is set between the operation button 101 and the component mounting surface (upper surface) of the printed wiring board 104.
In the illustrated configuration, only one operation button 101 is provided, but actually, a plurality of units including the operation buttons 101 are provided corresponding to a plurality of selection units of the display device. Each switch 107 is connected to a control device (not shown) composed of, for example, a microcomputer.

  In the above configuration, when the user's finger touches the operation surface portion 101 a on the upper surface of the operation button 101, the finger becomes the ground side and a capacitor is formed by the finger and the touch detection electrode 102, which is printed via the FPC 105. The signal level of the touch detection circuit of the printed wiring board 104 is changed by being connected to the wiring unit 106 of the wiring board 104. The control device detects the contact of the finger with the operation button 101 based on the change in the signal level, and puts the selection unit corresponding to the operation button 101 in the display state on the screen of the display device (not shown). When the operation button 101 is pressed downward, and the switch 107 is pressed by the side surface portion 101d of the operation button 101, the switch 107 operates to output a selection signal and give it to the control device. Sets the selection unit corresponding to the switch 107 to a fixed display state and determines the selection of the selection unit.

However, in the switch device with a touch detection function configured as described above, the touch detection electrode 102 is assembled and fixed to the inner surface of the operation button 101 by press-fitting the inner case 101c into the operation button 101. Therefore, due to variations in assembly accuracy. The spacing between the operation unit 101a of the operation button 101 and the touch detection electrode 102 varies, and the capacitance of the capacitor formed by the touch detection electrode 102 and the finger becomes unstable, and the operation is performed. There is a problem that detection of a finger touch on the button 101 becomes unstable.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a switch device with a touch detection function capable of stably detecting a finger touch on an operation member.

  In order to achieve the above-described object, the switch device with a touch detection function of the present invention includes an operation member that is touched by a finger, a printed wiring board that is disposed corresponding to the operation member and has a wiring portion, A switch element that operates based on an operation member being operated, a side projectingly provided on the printed wiring board, a projecting base is electrically connected to the wiring unit, and a tip is a side on which a finger of the operation member contacts And a plate-like touch detection electrode located in the vicinity of the surface.

  According to the present invention, when the user's finger contacts the touch detection electrode, the touch detection electrode is connected to the ground via the finger, and the touch detection electrode and the finger have a stable capacitance. A capacitor is configured, and the stable electrostatic capacity can be detected on the wiring portion side of the printed wiring board, and a touch operation on the operation member can be reliably detected.

A first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a longitudinal sectional view of a switch device with a touch detection function. In FIG. 1, a plastic body 1 has a rectangular container shape with an open bottom surface. The body 1 is formed with a button storage hole 2, and the button storage hole 2 has an upper part smaller than other parts, and a step 2 a is formed therebetween. An operation button 3 as an operation member is accommodated in the button storage hole 2 of the body 1 so as to be movable in a predetermined direction (vertical direction in FIG. 1). The operation button 3 is formed of a light-transmitting plastic and is formed in a rectangular container shape having an open lower surface, and the upper portion is made smaller than other portions, and a step portion 3c is formed between the small portion 3a and the large portion 3b. Is formed.

  As shown in FIG. 1, a printed wiring 4 is disposed below the operation button 3 so as to correspond to the lower surface of the operation button 3, and is fitted into the opening 1 a on the lower surface of the body 1. . The printed wiring board 4 has a predetermined printed wiring. Further, a flexible body 5 having a hollow conical shape made of an insulating material such as rubber (a state in which the cup is turned down) is fixed to a component mounting surface (upper surface) of the printed wiring board 4, and a pressure receiving portion 5a on the upper portion thereof. Is in contact with the pressing portion 3d on the lower surface of the operation button 3 from below and biased upward. Thereby, the operation button 3 is urged upward, the step portion 3 c abuts on the step portion 2 a of the body 1, and the upper portion of the small portion 3 a is held in a state of slightly protruding from the upper surface of the body 1. The movable contact 6a is provided on the lower surface of the pressure receiving portion 5a of the flexible body 5, and the fixed contacts 6b and 6b are provided on the component mounting surface of the printed wiring board 4 so as to face the movable contact 6a. 6 is configured.

As shown in FIG. 1, the wiring portion 7 is provided on the component mounting surface of the printed wiring board 4, and the touch detection electrode 8 is projected. This touch detection electrode 8 is
As shown in FIG. 2, a rectangular plate shape made of a conductive material such as copper is formed, and a connecting piece 8b protruding downward is formed on the protruding base portion 8a. The connecting piece 8b penetrates the wiring portion 7 and the wiring The portion 7 is soldered on the soldering surface (lower surface) of the printed wiring board 4. In the touch detection electrode 8, the intermediate portion extends along the left side surface, which is one side surface of the operation button 3, and the end surface of the distal end portion 8 c is the upper surface of the small portion 3 a of the operation button 3 (the surface on the side where the fingers come into contact). ) And protrude slightly upward from this position.

  In the configuration described above, only one operation button 3 is provided. Actually, however, it corresponds to a plurality of selection units of a display device (not shown) as shown in FIG. 3 showing a top view of the switch device with a touch detection function. A plurality of units including the operation buttons 3 are provided, for example, two. Each switch 6 is connected to a control device (not shown) composed of, for example, a microcomputer. A cover 9 that closes the body 1 is fitted into the opening 1 a on the lower surface of the body 1.

  Next, the touch detection circuit 10 of the switch device with a touch detection function will be described with reference to FIG. The touch detection circuit 10 is a general capacitance detection circuit, and includes an oscillation unit 11 (one terminal is connected to the ground) that outputs a high-frequency signal, a load resistor 12, a high-frequency signal detection and smoothing. It comprises a detector 13 and an operational amplifier 14 for performing the above.

  The touch detection electrode 8 is connected to the output terminal (the other terminal) of the oscillating unit 11 via the load resistor 12 and the wiring unit 7. The detection unit 13 includes a diode and a capacitor, and a high frequency signal from the oscillation unit 11 is input via the load resistor 12. The output of the detection unit 13 is input to the control device as a signal Vout amplified and offset through the operational amplifier 14. The oscillation unit 11, the load resistor 12, the detection unit 13, and the operational amplifier 14 are configured as a packaged capacitance detection IC 15.

Next, the operation of this embodiment will be described.
When the user's finger approaches the tip 8c of the touch detection electrode 8 near the upper surface of the small portion 3a of the operation button 3, the user's finger is in a state of being connected to the ground. 8 and the user's fingers constitute a variable capacitor C (see FIG. 4). In such a state, when the user's finger contacts the upper surface of the tip 8c of the touch detection electrode 8, the capacitance of the capacitor C hardly changes. Thereby, the wiring part 7 of the printed wiring board 4 is connected to the ground via the capacitor C composed of the touch detection electrode 8 and the finger. Therefore, the high-frequency signal output from the oscillation unit 11 is divided by the resistance value of the load resistor 12 and the impedance of the capacitor C and input to the detection unit 13.

As a result, the level of the high-frequency signal input to the detection unit 13 is smaller than in the state where the finger is not touching the touch detection electrode 8, so that the signal Vout output via the detection unit 13 and the operational amplifier 14 is reduced. The level is also reduced. The control device detects the contact of the finger with the touch detection electrode 8 (operation button 3) based on the change in the level of the signal Vout, and temporarily selects the selection unit corresponding to the operation button 3 on the screen of the display device (not shown). Display state.
Thereafter, when the user presses the operation button 3 downward and the switch 6 is pressed by the pressing portion 3d of the operation button 3, the switch 6 operates (turns on) and the on signal is selected as a selection signal to the control device. The control device changes the selection unit corresponding to the operation button 3 to a fixed display state, and determines the selection of the selection unit.

  As described above, according to the present embodiment, the printed wiring board 4 is provided with the wiring portion 7 and the plate-like touch detection electrode 8 is protruded, and the protruding base portion 8a is electrically connected to the wiring portion 7, In addition, the tip 8c of the touch detection electrode 8 is positioned near the upper surface of the operation button 3. Therefore, only by projecting the touch detection electrode 8 on the printed wiring board 4, the contact position relationship of the finger with respect to the touch detection electrode 8 can be made constant, and the user can place the finger on the touch detection electrode 8. Since the stable capacitor C can be constituted by the touch detection electrode 8 and fingers only by making contact, touch detection for the touch detection electrode 8, that is, equivalently, touch detection for the operation button 3 can be reliably performed. it can.

  In this case, as described above, the touch detection electrode 8 is fixed so that the contact positional relationship with the finger is constant only by projecting the touch detection electrode 8 on the printed wiring board 4. The fixing means such as 101c may not be used, and the configuration is simplified.

5 and 6 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.
As shown in FIG. 5, the upper surface of the small portion 3a of the operation button 3 (the surface on the side where the fingers come into contact) is formed as an arcuate surface 3e whose left and right central portions slightly protrude upward. As shown in FIG. 6, a contact portion 8 d having a rectangular frame shape is formed at the distal end portion 8 c of the touch detection electrode 8 so as to surround the arc surface 3 e of the operation button 3.

  Further, a transparent or translucent waterproofing film 16 that covers the entire upper surface of the body 1 is attached to the upper surface of the body 1. A conductive coating 17 is formed on the back surface of the film 16 by sputtering or plating with a conductive material corresponding to each operation button 3. The conductive film 17 is in contact with the entire arc surface 3 e of the operation button 3 and the peripheral portion is in contact with the contact portion 8 d of the touch detection electrode 8 and is electrically connected thereto.

Thus, when the user's finger touches the conductive film 17 portion of the film 16, that is, the portion corresponding to the contact portion 3e of the operation button 3, the wiring portion 7 includes the touch detection electrode 8, the rectangular frame-shaped contact portion 8d, It is connected to the ground via the conductive film 17, the film 16, and fingers, and a capacitor (corresponding to the capacitor C in FIG. 4) is formed between them.
In this case, since the film 16 and the conductive film 17 have a constant thickness dimension, the capacitance of the capacitor formed between the touch detection electrode 8 and the ground becomes stable. Therefore, also in the second embodiment, the touch detection on the operation button 3 can be reliably performed as in the above-described embodiment.

  According to the second embodiment described above, since the entire upper surface of the body 1 is covered with the waterproof film 16, it is possible to prevent water droplets from entering the gap between the body 1 and the operation button 3. It is possible to prevent the capacitance of the capacitor composed of the touch detection electrode 8 and fingers from changing due to water droplets. In this case, a rectangular frame-shaped contact portion 8 d surrounding the contact surface 3 e of the operation button 3 is provided at the tip portion 8 c of the touch detection electrode 8, and a conductive film 17 in contact with the contact portion 8 d is provided on the film 16. Therefore, even if the user's finger touches any part of the film 16 corresponding to the contact surface 3e of the operation button 3, this can be detected.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following modifications and expansions are possible.
In the second embodiment, the film 16 and the conductive film 17 may be provided as necessary.
In the above embodiment, the operation button 3 is formed in a rectangular container shape having an open bottom surface, but may be formed in a circular container shape having an open bottom surface, for example.
In the above-described embodiment, the operation button 3 is provided so as to be pressed by the body 1, but may be provided so as to be slidable.

In the above embodiment, a display device having a plurality of selection units is provided, and the selection of the selection unit is determined by the operation of the switch 6. For example, the display unit simply has a plurality of display units corresponding to a plurality of operation buttons. A display device may be provided.
In the above embodiment, the switch device with a touch detection function is arranged in the vertical direction. However, for example, it may be arranged in the horizontal direction, or the vertical direction may be reversed.

1 is a longitudinal sectional view of a switch device with a touch detection function according to a first embodiment of the present invention. Perspective view of electrode for touch detection Top view of switch device with touch detection function The figure which shows the equivalent circuit of the touch detection circuit FIG. 1 equivalent view showing a second embodiment of the present invention. 2 equivalent diagram FIG. 1 equivalent diagram showing a comparative example

Explanation of symbols

  In the drawings, 1 is a body, 3 is an operation button (operation member), 4 is a printed wiring board, 6 is a switch (switch element), 7 is a wiring portion, 8 is a touch detection electrode, 8a is a protruding base, and 8c is a tip. Reference numeral 8d denotes a contact portion, 10 denotes a touch detection circuit, 16 denotes a film, and 17 denotes a conductive film.

Claims (2)

An operation member touched by a finger;
A printed wiring board disposed corresponding to the operation member and having a wiring portion;
A switch element that operates based on an operation of the operating member;
A plate-like touch detection electrode that is provided on the printed wiring board, has a protruding base portion electrically connected to the wiring portion, and has a tip portion located in the vicinity of the surface of the operation member on which the finger contacts. A switch device with a touch detection function.   The switch device with a touch detection function according to claim 1, wherein a tip end portion of the touch detection electrode is formed so as to surround a surface of the operation member on a side on which a finger contacts.

Images