JP5482807B2 - Capacitive touchpad with key switch - Google Patents

Description

  The present invention relates to an input device constituting an input operation unit of an electronic device, and more particularly to a touchpad with a key switch having a structure in which a metal dome switch and a capacitive touchpad are integrated.

  Electronic devices such as digital television broadcast receivers in recent years have become multifunctional, and remote controllers as input devices of such digital television broadcast receivers include capacitive touches in addition to key switches. A pad is provided.

  The key switch is used for channel selection, pointer operation, and the like, and the capacitive touch pad is used for input such as pointer operation, character input, and page switching.

  Rather than providing a key switch and a capacitive touch pad on separate areas on the remote controller's operating surface, a structure in which the key switch and the capacitive touch pad are integrated, that is, the key switch in the touch pad area. It is done to provide.

  An example of a remote controller including such a touchpad with a key switch is disclosed in Patent Document 1. This remote controller includes a capacitive touch pad with a key switch in which a plurality of metal dome switches functioning as a pointer direction key switch and a determination key switch and a capacitive touch pad are integrated.

  As shown in FIG. 7, this capacitive touch pad with a key switch has a touch pad detection electrode (not shown) formed on a multilayer printed board 10, and a metal dome switch 12 on the multilayer printed board 10. Is mounted and fixed. The entire surface of the multilayer printed board 10 is covered with a rubber sheet 14. The periphery of the rubber sheet 14 is bonded to the multilayer printed board 10 with a double-sided adhesive tape 16.

  On the rubber sheet 14, a keyed touch sheet 20 having keys 18 is provided. The touch sheet 20 is a sheet for touching a finger when inputting a capacitive touch pad. Since it is necessary to press the key 18, the touch sheet 20 is made of an elastic material, not a hard material.

JP 2011-82713 A

  The conventional capacitive touch pad with a key switch disclosed in Patent Document 1 has the following problems.

(1) Detection accuracy of the capacitive touch pad To increase the detection accuracy of the capacitive touch pad, the dielectric constant between the detection electrode formed on the multilayer printed circuit board 10 and the touch sheet 20 is kept high. And it is necessary to keep the distance between the detection electrode and the touch sheet 20 constant.

  A conventional capacitive touch pad with a key switch is provided with a rubber sheet 14 between the detection electrode and the touch sheet 20. Silicon rubber suitable as a material for the rubber sheet 14 has a low relative dielectric constant of 3.0 to 3.5, and in addition, between the metal dome switch 12 and the touch sheet 20 so that the key 18 can be pressed well. In addition, it is necessary to provide a space larger than the diameter of the metal dome switch 12, and the dielectric constant between the detection electrode and the touch sheet 20 cannot be kept high.

  In addition, the conventional capacitive touch pad with key switch can keep the distance between the detection electrode and the touch sheet 20 constant by pressing the rubber sheet 14 depending on how the finger touches when inputting. I can't.

  Therefore, the conventional touchpad with a key switch has a problem that detection accuracy is low.

(2) Click feeling when the metal dome switch 12 is pressed In the conventional touchpad with key switch, when the key 18 is pressed, the metal dome switch 12 is pressed with the rubber sheet 14 interposed therebetween. Since the rubber sheet 14 is elastic, there is a problem that when the key 18 is pressed, the click feeling is lower than when the metal dome switch 12 is directly pressed.

  The objective of this invention is providing the touchpad with a key switch which solved the said subject.

  The present invention relates to a capacitive touch pad with a key switch in which a key switch and a capacitive touch pad are integrated, wherein the capacitive touch pad includes a printed circuit board on which detection electrodes are formed, and the detection. A hard dielectric plate provided on the electrode, and an elastic touch sheet provided on the hard dielectric plate, wherein the key switch includes a region of the printed circuit board on which the detection electrode is formed; A plurality of metal dome switches formed in the same region, a plurality of keys displayed on the surface of the elastic touch sheet corresponding to each of the plurality of metal dome switches, the elastic touch sheet and the metal A plurality of metal dome pressing members provided between the dome and pressing the metal dome of the corresponding metal dome switch when the key is pressed; , Characterized in that.

  According to the capacitive touch pad with a key switch of the present invention, since the hard dielectric plate is used between the elastic touch sheet and the detection electrode, the dielectric constant between the elastic touch sheet and the detection electrode is increased, and Since the distance between the elastic touch sheet and the detection electrode can be kept constant, good detection accuracy can be obtained.

  Further, since the metal dome is pressed by the metal dome pressing member, the click feeling can be improved as compared with the conventional capacitive touch pad with key switch.

It is a top view of a remote controller provided with the touchpad with a key switch which is the 1st Embodiment of this invention. It is sectional drawing of the electrostatic capacitance type touchpad part containing one metal dome switch. It is a top view which shows the electrically conductive film pattern of the electrode formed in the multilayer printed circuit board of the remote controller of FIG. It is a figure which shows a state when the metal dome switch of FIG. 2 is turned on. It is the fragmentary top view and fragmentary sectional view which show the structure of the dielectric material board of the touchpad with a key switch which is the 2nd Embodiment of this invention, a hinge, and the metal dome pressing member. It is a figure which shows a state when the metal dome switch of FIG. 5 is turned on. It is sectional drawing of the conventional touchpad with a key switch.

[First embodiment]
A remote controller including a capacitive touch pad with a key switch according to the first embodiment of the present invention will be described. In this capacitive touch pad with key switches, a key switch for channel selection is provided in the area of the capacitive touch pad for pointer operation.

  As shown in FIG. 1, the remote controller 30 includes a capacitive touch pad 32 with a key switch. In the capacitive touch pad 32 with key switches, the channel selection key switch 34 and the capacitive touch pad 36 are integrated.

(Structure of capacitive touch pad)
First, the structure of the capacitive touch pad 36 will be described with reference to FIG. As shown in FIG. 2, the capacitive touch pad 36 includes a touch sheet 40, a detection electrode 44 formed on the surface of the multilayer printed circuit board 42 of the remote controller 30, and the touch sheet 40 and the detection electrode 44. And a hard dielectric plate 46 provided on the substrate.

  The touch sheet 40 is a sheet for moving a finger on the touch sheet 40, and is made of an elastic material. The reason for using the elastic material is that it must be elastic in order to push down a metal dome pressing member 74 described later from above the touch sheet 40. A PET (polyethylene terephthalate) sheet is used as an example of the elastic material. The touch sheet 40 constitutes an elastic touch sheet according to the present invention.

  The detection electrode 44 is an electrode for detecting the position of the finger on the touch sheet 40 by a change in capacitance. By detecting the position of the finger, the pointer can be operated.

  The detection electrode 44 is formed of a conductive film made of copper on the surface of the multilayer printed board 42. An example of the conductive film pattern of the detection electrode 44 is shown in FIG. The detection electrode 44 is composed of a conductive film pattern extending in the X direction of the orthogonal X direction and Y direction, and a conductive film pattern extending in the Y direction.

  The conductive film pattern in the Y direction is formed by arranging in parallel a plurality of rectangular conductive film patterns as shown in the figure and connecting adjacent square conductive film patterns with wiring (not shown). It is.

  As for the conductive film pattern in the X direction, square conductive film patterns as shown in the figure are arranged in series, and adjacent rectangular conductive film patterns are connected in parallel through a through hole and connected in lower layers. It is a thing. FIG. 2 is a partial cross-sectional view in the X direction, wherein the through hole is indicated by reference numeral 48 and the lower layer wiring is indicated by reference numeral 50.

  The hard dielectric plate 46 is for maintaining a distance between the touch sheet 40 and the detection electrode 44 and ensuring a dielectric constant between the touch sheet 40 and the detection electrode 44. Therefore, it is preferable to use a material having a high dielectric constant. As an example of such a hard dielectric plate 46, an acrylic resin plate is used. The acrylic resin has a relative dielectric constant of 2.7 to 4.5 and has a hardness comparable to that of aluminum. In addition to the acrylic resin, other materials such as ABS (acrylonitrile butadiene styrene) resin having a relative dielectric constant of 2.4 to 4.1 may be used as the material of the hard dielectric plate 46.

  Such a hard dielectric plate 46 is bonded to the multilayer printed board 42 with a double-sided adhesive tape (not shown).

(Channel selection key switch structure)
As shown in FIG. 1, a channel selection key switch 34 is included in the area of the capacitive touch pad 36 described above. The key switch is a switch for inputting ON / OFF by pressing a key, and basically includes a key and a switch.

  In this embodiment, a known metal dome switch is used as the switch. As shown in FIG. 2, the metal dome switch 52 includes a central electrode 54 formed on the same surface of the multilayer printed board 42 on which the detection electrode 44 is formed, and a peripheral electrode 56 surrounding the central electrode 54, and A metal dome 58 that is conductively joined to the surrounding electrode 56 is provided. As shown in FIG. 3, the central electrode 54 and the peripheral electrode 56 are formed in a region where the detection electrode 44 of the capacitive touch pad 36 is formed. Therefore, the conductive film of the detection electrode 44 is not formed in the formation part of the central electrode 54 and the peripheral electrode 56.

  As shown in FIG. 2, the center electrode 54 is connected to a wiring 62 formed on the back surface of the multilayer printed circuit board 42 through a through hole 60 penetrating the multilayer printed circuit board 42. The peripheral electrode 56 is connected to a wiring 66 formed on the back surface of the multilayer printed circuit board 42 through a through hole 64 penetrating the multilayer printed circuit board 42.

  When the top of the metal dome 58 is pressed, the metal dome 58 bends and the top contacts the central electrode 54 on the multilayer printed board 42. As a result, the central electrode 54 and the peripheral electrode 56 are conducted through the metal dome 58. When the pressing to the top of the metal dome 58 is released, the metal dome 58 returns to its original shape, and the central electrode 54 and the peripheral electrode 56 are rendered non-conductive. In the present embodiment, a metal dome pressing member 74 which is a single member described later is used to press the metal dome 58.

  The hard dielectric plate 46 is provided with a through hole 70 at a location corresponding to the metal dome 58. A lower portion of the through hole 70 has a dome-shaped recess 72 that accommodates the metal dome 58. The reason why the metal dome 58 is accommodated by forming such a dome-shaped recess 72 is to prevent a space between the touch sheet 40 and the detection electrode 44 in a region other than the portion where the metal dome 58 exists. It is to do. This is because such a space is not preferable because the dielectric constant between the touch sheet 40 and the detection electrode 44 is lowered.

  The metal dome pressing member 74 described above is composed of a head portion 74a and a leg portion 74b. As an example of the shape of the metal dome pressing member 74, the head 74a is a disc and the leg 74b is a cylinder. Similar to the hard dielectric plate 46, such a pressing member is made of acrylic resin. This is to increase the dielectric constant between the touch sheet 40 and the detection electrode 44.

  The leg part 74 b of the metal dome pressing member 74 is inserted into the through hole 70, and the tip of the leg part 74 b is disposed in contact with the top part of the metal dome 58. Further, the upper portion of the through hole 70 has a recess 76 that accommodates the head 74 a of the metal dome pressing member 74.

  In a state where the tip of the leg portion 74b of the metal dome pressing member 74 is in contact with the top portion of the metal dome 58, there is a gap between the bottom surface 76a of the recess 76 and the lower surface 74c of the head portion 74a of the pressing member. As shown in FIG. 4, when the metal dome pressing member 74 is pushed down by the finger 78 from above the touch sheet 40, a distance that can be pushed down until the metal dome 58 bends and contacts the center electrode 54 is secured. To do.

  Further, in the state where the tip of the leg portion 74 b of the metal dome pressing member 74 is in contact with the top of the metal dome 58, as shown in FIG. 2, the upper surface of the hard dielectric plate 46 and the metal dome pressing member 74. The upper surface of the head 74a is positioned on the same plane. This is because it is preferable that the surface of the touch sheet 40 is flat when a finger is slid on the touch sheet 40 during input using the capacitive touch pad 36.

  The touch sheet 40 also functions as a display sheet for displaying keys when a channel is selected using the channel selection key switch 34 (see FIG. 1). In this case, a key including channel numbers 1 to 12 is printed on the surface portion of the touch sheet 40 above the head portion 74a of the metal dome pressing member 74 to configure the key. In FIG. 1, the keys are printed as numbers surrounded by a square frame.

  In addition, the structure of the detection electrode 44 in this embodiment mentioned above is an example, and the detection electrode of any known structure of a capacitive touchpad can be used. For example, the detection electrode may be formed by forming an electrode pattern in the X direction and the Y direction on a multilayer printed board with a two-layer structure. In this case, the center electrode 54 and the peripheral electrode 56 of the metal dome switch 52 are formed in the upper layer of the detection electrode.

[Second Embodiment]
Next, a capacitive touch pad with a key switch according to a second embodiment of the present invention will be described. In this embodiment, the metal dome pressing member is not formed as a single member as in the first embodiment, but is formed integrally with the hard dielectric plate and supported by the dielectric plate with a hinge so that the pressing member can be pushed down. I tried to do it. The hinge itself is also formed integrally with the dielectric plate. That is, the hard dielectric plate, the metal dome pressing member, and the hinge are integrally formed of the hard dielectric. The hard dielectric plate can also be used as the remote controller casing.

  FIG. 5 is a diagram showing the structure of the hard dielectric plate 80, the metal dome pressing member 82, and the hinge 84 that are integrally molded. In order to simplify the drawing, only the portion including two pressing members is shown, and the touch sheet is not shown. 5A is a partial plan view, and FIG. 5B is a cross-sectional view taken along the line AA in FIG. 5A.

  The metal dome pressing member 82 includes a head portion 82a and a leg portion 82b. As an example of the shape of the metal dome pressing member 82, the head 82a is a disc and the leg 82b is a cylinder.

  As shown in FIG. 5, the head 82 a of the metal dome pressing member 82 is supported on the hard dielectric plate 80 by hinges 84 on both sides. The hinge 84 has a small thickness and meandering to make it elastic so that it can be easily pushed down when a key (not shown) is pressed.

  The structure of the multilayer printed circuit board 42 is the same as that of the first embodiment. In FIG. 5B, the detection electrode is not shown in order to simplify the drawing.

  The tips of the leg portions 82 b of the metal dome pressing member 82 are arranged so as to contact the top of the metal dome 58.

  When the tip of the leg portion 82b of the metal dome pressing member 82 is in contact with the top of the metal dome 58, the upper surface of the hard dielectric plate 80, the upper surface of the head portion 82a of the metal dome pressing member 82, and the hinge The upper surface of 84 is located on the same plane. This is because the surface of the touch sheet is preferably flat when the finger is slid on the touch sheet at the time of input using the capacitive touch pad, as in the first embodiment.

  FIG. 6 is a partial cross-sectional view in a state where the touch sheet 40 is provided. As shown in FIG. 6, when the key printed on the touch sheet 40 is pressed with the finger 78, the metal dome pressing member 82 supported by the hinge 84 is pressed down, the metal dome 58 is bent, and the metal dome switch is turned on. To do.

  According to this embodiment, since the metal dome pressing member 82 is not a single member, there is an advantage that the number of parts is reduced.

  The capacitive touch pad with a key switch of the present invention can be used not only for a remote controller but also for input devices of various electronic devices.

30 Remote controller 32 Capacitive touchpad with key switch 34 Channel selection keyswitch 36 Capacitive touchpad 40 Touch sheet (elastic touch sheet)
42 Multilayer Printed Circuit Board 44 Detection Electrode 46, 80 Hard Dielectric Plate 52 Metal Dome Switch 54 Center Electrode 56 Peripheral Electrode 58 Metal Dome 70 Through-hole 74, 82 Metal Dome Pressing Member 84 Hinge

Claims (4)

In capacitive touch pad with key switch that integrates key switch and capacitive touch pad,
The capacitive touchpad is
A printed circuit board on which detection electrodes are formed;
A hard dielectric plate provided on the detection electrode;
An elastic touch sheet provided on the hard dielectric plate;
The key switch is
A plurality of metal dome switches formed in the same area as the area of the printed circuit board on which the detection electrodes are formed;
In correspondence with each of the plurality of metal dome switches, a plurality of keys displayed on the surface of the elastic touch sheet,
A plurality of metal dome pressing members that are provided between the elastic touch sheet and the metal dome and press the metal dome of the metal dome switch corresponding to the key being pressed;
Capacitive touchpad with key switch. The hard dielectric plate has a through hole,
The metal dome pressing member is disposed in contact with the top of the metal dome so as to be inserted into the through hole and press the metal dome when the key is pressed.
The capacitive touch pad with a key switch according to claim 1. The hard dielectric plate and the metal dome pressing member are formed of acrylic resin,
The capacitive touch pad with a key switch according to claim 2. The metal dome pressing member is supported by a hinge on the hard dielectric plate,
The metal dome pressing member, the hinge, and the hard dielectric plate are integrally formed,
The metal dome pressing member is disposed in contact with the top of the metal dome so as to press the metal dome when the key is pressed.
The capacitive touch pad with a key switch according to claim 1.

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