JP4438648B2 - Input device - Google Patents

Description

  The present invention relates to an input device that is input using a capacitance change sensor, and more particularly to an input device that can be suitably used for an input device such as a small portable terminal having a plurality of input keys.

  In general, an input device having a plurality of input keys is widely used for a numeric keypad, a cross key, and the like of a keyboard of a personal computer, a calculator, and a mobile phone. Currently, there are various input methods as such input devices. Among them, an input device formed using a capacitance change proximity sensor is formed using other sensors. Compared with an input device, it is possible to more efficiently achieve a reduction in thickness and cost.

  FIG. 12 shows an example of this type of capacitance change type input device 101. This input device 101 detects an input key 102 printed on a surface sheet, a plate-like electrode 103 disposed at a position facing the input key 102, and a change in the capacitance C of the electrode 103. And a control unit. And since the control part (not shown) detects the change of the electrostatic capacitance C of the electrode 103 generated when the human body H approaches or contacts the input key 102, it is possible to perform a desired key input. (See Patent Document 1). Thus, it can be used for, for example, a sheet-like input device.

  The capacitance change type input device 101 described above can also be used as a push-type input device. For example, as shown in FIG. 13 and FIG. 14, this capacitance change type input device 101 has a metal inversion dome 105 fixed to an annular electrode 103 formed on a substrate 106, and An input key 102 that can be pressed down is disposed so as to face the head. In addition, a grounded contact member 107 is formed at the center of the electrode 103 while being insulated from the electrode 103. Therefore, when the human body H approaches the input key 102, as shown in FIG. 13A, the change in the capacitance C of the inversion dome 105 that is in contact with the electrode 103 is detected. Key input can be performed. Further, when the human body H touching the input key 102 depresses the input key 102, the shape of the reversing dome 105 changes in the direction of being recessed and reversed as shown in FIG. 13B. By detecting the electrostatic state of the electrode 103 that is in contact with the contact member 107 at the center and is in contact with the contact member 107 via the inversion dome 105 (the electric charge of the electrode 103 becomes 0 when the ground state is established) Key input can be performed by pressing the key 102 (see Patent Document 2). Thereby, it is possible to obtain a good click feeling even in the capacitance change type input device 101. Further, since a two-step switching operation in which the human body H is brought into contact with the input key 102 and then pressed is possible, it can be used for a two-stage switch such as a shutter button of a digital camera, for example.

  Here, in any of the capacitance change type input devices 101 such as the input device that detects only the proximity state described above or the input device that detects both the proximity state and the pressed state, the electrode 103 formed on the substrate 106 is used. In order to detect the input key 102 that has been input by detecting the capacitance C, it is necessary to change the capacitance C of the electrode 103 as a major premise. Here, the capacitance C of the electrode 103 is proportional to the facing area Sh between the detected body (human body H) and the electrode 103 and inversely proportional to the facing distance d from the detected body (human body H) to the electrode 103. There is a relationship (see Equation 1 below). Further, the capacitance C of the electrode 103 can be changed by changing the facing area Sh and the facing distance d (see Patent Documents 1 and 2).

JP 2004-2011175 A Japanese Patent Application Laid-Open No. 2004-334738

  However, in the capacitance change type input device 101, the above-mentioned facing distance d is not a value that can be set indefinitely, but a distance at which the control unit can detect a change in the capacitance of the electrode 103, that is, Since the input device 101 does not operate unless it is set within the range of the operating distance, the upper limit is determined. Therefore, there is a problem that the facing distance d, which is the disposition distance from the front surface of the input key 102 (surface on which the human body H is close) to the electrode 103, may be limited to an extremely short distance.

  For example, as shown in FIG. 12, when an air layer formed between the input key 102 and the substrate 106 is interposed with a thickness of about 0.6 to 0.9 mm, it is compared with a solid such as the input key 102. Since the relative permittivity of air is extremely small, the input key 102 is limited to a thickness of about 0.3 to 0.6 mm. As a result, the maximum facing distance d is limited to about 1.2 mm. In other words, when the capacitance change type input device 101 is disposed in another electronic device, the facing distance d is limited to a short distance as described above, which is not preferable.

  Further, as shown in FIGS. 13 and 14, a capacitance reversal type input having a good click feeling and a mechanical contact switch function by arranging a metal inversion dome 105 behind an input key 102 that can be pressed freely. In the case of the device 101, the facing distance d ′ that is the operating distance is the distance from the front surface of the input key 102 to the head of the inverting dome 105, and thus the facing distance d (see FIG. 12). However, since the facing area S is reduced by the convex portion 102a of the input key formed to improve the click feeling, even when the input key 102 is in contact with the metal inversion dome 105, the facing of the facing portion S is reduced. The distance d has not been solved until the problem that the distance d is limited to a short distance as described above.

  Therefore, the present invention has been made in view of these points, and provides an input device that can increase the operating distance of the input device without changing the shape of the electrode formed on the substrate. Is the object of the present invention.

  Another object of the present invention is to provide an input device capable of increasing the operating distance of the input device and obtaining a good click feeling.

  Another object of the present invention is to provide an input device that can be applied to various input key shapes while increasing the operating distance of the input device.

In order to achieve the above-described object, the input device according to the present invention includes, as a first aspect, a first electrode formed on a substrate and a dielectric made to face the first electrode. An input key, a non-grounded second electrode disposed between the first electrode and the front surface of the input key, and capacitance detection for detecting a change in capacitance of the first electrode Means. The input device according to the first aspect includes a conductive member disposed between the first electrode and the second electrode in contact with each other. Further, the second electrode is arranged at a position where the capacitance of the second electrode is changed by a human body approaching the front surface of the input key.

According to the first aspect of the present invention, the operating distance for changing the capacitance of the first electrode is the distance from the operator's fingertip (detected body) to the second electrode. The operating distance from the object to be detected) to the surface of the electrode (the first electrode in the present invention) can be made longer than before.

According to a second aspect of the input device of the present invention, the input key provided in the input device according to the first aspect is formed so as to be freely pressed, and the conductive member generates a reversal force with respect to the pressing direction of the input key. It is characterized by being formed.

According to the second aspect of the present invention, it is possible to give a good click feeling during key input.

According to a third aspect of the input device of the present invention, when the contact member formed on the substrate and insulated from the first electrode of the input device of the second aspect is pressed when the input key is pressed. It is characterized by being disposed at a position in contact with the electrode or the conductive member.

According to the third aspect of the present invention, the function of the mechanical contact switch can be added to the function of the proximity switch.

According to a fourth aspect of the input device of the present invention, the input key provided in the input device according to any one of the first to third aspects covers a position where the plurality of first electrodes disposed are opposed to each other. It is characterized by being integrally formed.

According to the fourth aspect of the present invention, it is not necessary to arrange the input keys and the first electrodes in a one-to-one correspondence, so that the present invention can be used for, for example, direction keys.

According to a fifth aspect of the input device of the present invention, the capacitance detecting means provided in the input device according to any one of the first to fourth aspects includes a clock signal generating means for generating a clock signal, and an input key. A delay means for performing delay processing on the clock signal according to the capacitance of the electrode when a human body approaches or comes into contact with the clock signal, a clock signal that has been subjected to delay processing, and a clock signal that has not been subjected to delay processing are input, and delay processing is performed. AND means for outputting an output signal in accordance with the amount of delay of the clock signal, smoothing means for smoothing the output signal of the AND means into an analog signal, and A / D for converting the analog signal into a digital signal It is characterized by comprising conversion means and a control unit for detecting an input key that a human body approaches or touches based on the obtained digital signal.

According to the fifth aspect of the present invention, it is possible to form a capacitance detecting means having easy moldability and detection reliability.

  With the input device of the present invention, it is possible to increase the operating distance, so that the allowable range of the thickness of the input key is increased compared to the conventional case.

  In addition, since the present invention does not require a large design change as compared with the conventional capacitance change type input device, the operation distance can be improved quickly and inexpensively.

  Hereinafter, five embodiments of the input device of the present invention will be described with reference to FIGS.

Here, FIG. 1 to FIG. 11 will be described. FIG. 1 is a sectional view of a first embodiment of an input device according to the present invention. FIG. 2 shows capacitance detection means according to the first to fifth embodiments. FIG. 3 shows an example of a change in capacitance of the first electrode using a graph. FIG. 4 shows a cross-sectional view of a second embodiment of the input device of the present invention. FIG. 5 is a perspective view of the conductive member shown in FIG. FIG. 6 shows a cross-sectional view of a third embodiment of the input device of the present invention. FIG. 7 is a perspective view of the conductive member having the inverted dome shape shown in FIG. FIG. 8 shows a cross-sectional view of a fourth embodiment of the input device of the present invention. FIG. 9 is a perspective view of the conductive member formed integrally with the second electrode shown in FIG. FIG. 10 is a perspective view of a fifth embodiment of the input device of the present invention. FIG. 11 shows a cross-sectional view taken along arrow 11-11 in FIG.
(1) First Embodiment As shown in FIG. 1, an input device 1 according to a first embodiment is disposed in an electronic device as an input device such as a computer, a calculator, a mobile phone, or a PDA. This input device 1 includes a capacitance detection means (in FIG. 1) for detecting changes in the capacitance C1 of the input key 2, the substrate 6, the first electrode 3, the second electrode 4, and the first electrode 3. (Not shown).

  The input key 2 is printed on a dielectric surface sheet formed in a sheet shape. Further, as shown in FIG. 1, a non-grounded second electrode 4 formed in a flat plate shape is printed on the back surface of the input key 2. The thickness d2 of the input key 2 is formed so as not to exceed a distance that can change the capacitance C2 of the second electrode 4 when a human body approaches the front surface. Specifically, it is about 2.1 to 2.4 mm. The thickness of the conventional input key is about 0.3 to 0.6 mm.

  A flat plate-like first electrode 3 is formed on the insulating substrate 6 so as to face the input key 2 and the second electrode 4. That is, the first electrode 3 and the second electrode 4 are formed so as to have a parallel plate capacitor relationship. The facing distance d1 between the first electrode 3 and the second electrode 4 is set with a positional relationship in which the capacitance C1 of the first electrode 3 changes due to the presence of the second electrode 4. Has been. Specifically, it is about 0.6 to 0.9 mm, and this set value is about the same as the conventional one.

  Capacitance detection means for detecting a change in the capacitance C1 of the first electrode 3 (A, B, C...) Is connected to one end of the conducting wire connected to the first electrode 3. ing. As shown in FIG. 2, this capacitance detection means is connected to detection channels CH (1, 2, 3,...) Prepared for the number of formed first electrodes 3 and detection channels CH. The control part 16 is formed. Each detection channel CH includes a clock signal generation means 11, a delay means 12 (A, B, C,...), A logical product means 13 (A, B, C,...), And a smoothing means 14 (A , B, C,...) And A / D conversion means 15 (A, B, C,...).

  The clock signal generation means 11 is formed so as to continuously output a regular pulse signal having a predetermined frequency. One output terminal of the clock signal generating means 11 is connected to the input terminal of the delay means 12, and the other output terminal is connected to the input terminal of the AND means 13. Each detection channel CH is formed to share the clock signal generation means 11.

  The delay means 12 is formed having the resistor R (1, 2, 3,...) And the first electrode 3 described above. The output terminal of the delay means 12 is connected to the input terminal of the logical product means 13.

  The logical product means 13 is formed using an AND gate circuit. The two input terminals of the logical product means 13 are connected to the output terminals of the clock signal generation means 11 and the delay means 12 as described above. The output terminal of the logical product means 13 is connected to the input terminal of the smoothing means 14.

  The smoothing means 14 connected to the output terminal of the AND means 13 is formed by a smoothing circuit having a resistance r (1, 2, 3,...) And a capacitor c (1, 2, 3,...). Has been. The output terminal of the smoothing means 14 is connected to the input terminal of the A / D conversion means 15 (A, B, C...).

  The A / D conversion means 15 connected to the smoothing means 14 is formed using an A / D converter. The output terminal of the A / D conversion means 15 is connected to one of the input terminals for the detection channel CH formed in the control unit 16.

  The control unit 16 to which each detection channel CH is connected has a CPU (not shown) that performs arithmetic processing. Further, the control unit 16 detects a change in the capacitance C1 of each first electrode 3 formed in each detection channel CH, so that the human body H comes into contact with or approaches from among the plurality of input keys 2. The input key 2 is detected.

  Next, the operation of the input device 1 of the first embodiment will be described.

  The input device 1 according to the present embodiment detects a specific input key 2 that has received an input operation from among a plurality of input keys 2 by detecting a change in the capacitance C1 obtained from the first electrode 3. To do. Here, since the second electrode 4 is disposed at a position facing the first electrode 3, the second electrode 4 is interposed between the first electrode 3 and the second electrode 4. A parallel plate capacitor that is not grounded is formed. At this time, as shown in FIG. 1, when the detected object (human body H) comes close to the front surface of the input key 2, the input key 2 between the human body H and the second electrode 4 is polarized, so that the second The capacitance C2 between the electrode 4 and the human body H changes. When the capacitance C2 changes, the capacitance C1 of the capacitor formed between the first electrode 3 and the second electrode 4 also changes in association with the capacitance C2. The capacitance detecting means detects the change in C1. That is, by disposing the second electrode 4 between the human body H and the first electrode 3, between the human body H and the second electrode 4 with the dielectric input key 2 that is easily polarized interposed therebetween. It is possible to enlarge the distance d2. As a result, the operating distance (the distance at which the capacitance C1 of the first electrode 3 changes depending on the detection object H) can be increased as compared with the conventional case.

  The capacitance C1 between the first electrode 3 and the second electrode 4 described above (hereinafter simply referred to as “capacitance C1”) and the capacitance between the second electrode 4 and the human body H. C2 (hereinafter simply referred to as “capacitance C2”) is a facing area Sc and a facing distance d1 between the first electrode 3 and the second electrode 4, and a facing area between the second electrode 4 and the human body H. It varies depending on Sh and the facing distance d2, and is generally obtained by the following equation (1).

Here, the facing area S is the facing area Sc between the first electrode 3 and the second electrode 4 in the case of the capacitance C1, and the second electrode 4 and the human body in the case of the capacitance C2. The area Sh facing H is used. Further, the facing distance d is the facing distance d1 between the first electrode 3 and the second electrode 4 in the case of the capacitance C1, and the second electrode 4 and the human body H in the case of the capacitance C2. The facing distance d2 is used. As the dielectric constant ε, the dielectric constant of air is used in the case of the capacitance C1, and the dielectric constant of the material of the input key 2 is used in the case of the capacitance C2.

  As described above, when the human body H is brought close to or in contact with the input key 2, the facing distance d2 between the second electrode 4 and the human body H is reduced and the facing area Sh is increased. The value of the capacity C2 increases. As a result, the value of the capacitance C1 also increases in association with it. Thus, the 1st electrode 3 from which the electrostatic capacitance C1 changed can detect the change of the said electrostatic capacitance C1 by an electrostatic capacitance detection means as shown in FIG. Although not shown in FIG. 1, a plurality of the first electrodes 3 are disposed on the substrate 6, and therefore, the first electrode 3 whose capacitance C1 does not change is also shown in FIG. is there. In FIG. 2, it is assumed that the capacitance C1 of the first electrode 3B is changed among the plurality of formed first electrodes 3A, 3B, 3C.

  When the capacitance C1 of the first electrode 3B changes, the resistance R2 provided in the delay means 12B of the detection channel CH2 to which the first electrode 3B is connected and the capacitance C1 of the first electrode 3B. The time constant CR calculated by the product increases. Therefore, the clock signal CK (see FIG. 3A) input from the clock signal generation unit 11 to the delay unit 12B is subjected to delay processing.

  When the time constant CR of the delay means 12 increases, as shown in FIG. 3B, the rectangular clock signal CK input to the delay means 12B is delayed to a triangular wave clock signal Sb (dashed line). . Here, since the second electrode 4B is disposed between the first electrode 3B and the human body H, when the human body H is not close to the input key 2B, the rectangular shape input to the delay means 12B. The clock signal CK is delayed by a rounded waveform (solid line) clock signal Sa in advance. When the second electrode 4B is not disposed between the first electrode 3B and the human body H, and the human body H is not close to the input key 2B, the input is made to the delay means 12B. The rectangular clock signal CK becomes a substantially rectangular (broken line) clock signal S0.

  When the clock signal Sb and the unprocessed clock signal CK when the time constant CR of the delay means 12B is large (when a human body approaches or touches the input key 2B) are input to the AND means 13B, FIG. As shown, a rectangular pulse wave Pb having a pulse width tb obtained with reference to the threshold value is output. On the other hand, when the clock signal Sa and the unprocessed clock signal CK when the time constant CR of the delay means 12B is small (when the human body is not approaching or in contact with the input key 2B) and the unprocessed clock signal CK are input to the AND means 13B, the same applies. A rectangular pulse wave Pa having a pulse width ta obtained in this manner is output. The magnitude relationship between the pulse width tb of the pulse wave Pb and the pulse width ta of the pulse wave Pa is tb <ta. That is, as the time constant CR increases, the pulse width t decreases and the output voltage value of the analog signal obtained from the smoothing means 14B decreases. Specifically, as shown in FIG. 3D, when the human body H approaches or comes into contact with the input key 2B, the output voltage value of the analog signal Ab becomes Vb, and the human body H moves away from the input key 2B. The value of the output voltage of the analog signal Aa is Va, which is larger than Vb.

  When the smoothed analog signal Aa or Ab is input to the A / D conversion means 15B, the analog signal Va or Vb obtained from the smoothing means 14B is detected with a predetermined sampling period, so that the digital signal Da or Converted to Db (not shown).

  The digital signal Da or Db obtained by the A / D conversion means 15B is sent to the control unit 16. The control unit 16 can detect whether or not the human body H is close to the input key 2 by detecting whether or not the digital signal Da or Db exceeds a predetermined threshold value. Yes.

That is, the input device 1 according to the first embodiment can change the capacitance C1 of the first electrode 3 via the second electrode 4 whose capacitance C2 has been changed by the human body. The operating distance from the fingertip (object to be detected) of the person to the surface of the electrode (first electrode 3 in the present embodiment) can be made longer than before.
(2) Second Embodiment As shown in FIG. 4, the input device 1 of the second embodiment is similar to the first embodiment in that the input key 2, the substrate 6, the first electrode 3, the second electrode 4, and Capacitance detection means (see FIG. 2) for detecting a change in the capacitance C1 of the first electrode 3 is provided. Unlike the first embodiment, the conductive member 5 is disposed between the first electrode 3 and the second electrode 4 so as to be in contact with the electrodes 3 and 4.

  The conductive member 5 is formed using a conductive material such as metal or conductive rubber. As shown in FIG. 3, the conductive member 5 is formed in a column shape so that it can be used as a spacer. Note that a lead wire may be used as the conductive member 5 if it is not used as a spacer.

  In the input device 1 according to the second embodiment formed as described above, since the first electrode 3 is electrically connected to the second electrode 4, the electrostatic between the second electrode 4 and the human body H is performed. The change in the capacitance C2 becomes the change in the capacitance C1 between the first electrode 3 and the second electrode 4 as it is. As a result, since the distance d1 between the first electrode 3 and the second electrode 4 is not taken into consideration, the electrode (from the operator's fingertip (detected body)) to the electrode (in this embodiment, the first electrode 3) is eliminated. ) Can be made longer than before.

  When the human body H is close to the input key 2B, the electrostatic capacitance detection means provided in the input device 1 of the second embodiment outputs the clock signal Sb delayed by the delay means 12 as in the first embodiment. Thereafter, a key input is detected by the same processing as in the first embodiment.

Since the first electrode 3 is electrically connected to the second electrode 4, when the human body H is not close to the input key 2B, the rectangular clock signal CK input to the delay means 12B is shown in FIG. As shown in (b), the clock signal S0 has a substantially rectangular shape (broken line), not a rounded waveform (solid line). Accordingly, the pulse wave output from the logical product means 13B becomes a rectangular pulse wave P0 having a pulse width t0 (ta <t0) as shown in FIG. 3C, and the analog wave obtained from the smoothing means 14B. The value of the output voltage of the signal A0 is V0 (Va <V0).
(3) Third Embodiment The input device 1 of the third embodiment is used as a two-stage input device such as a shutter switch of a digital camera. As shown in FIGS. 6A and 6B, the input device 1 includes an input key 2, a substrate 6, a first electrode 3, a second electrode 4, an inverted dome-shaped conductive member 5, and a contact member 7. And a capacitance detecting means (see FIG. 2) for detecting a change in the capacitance C1 of the first electrode 3.

  As shown in FIGS. 6A and 6B, the input key 2 is formed so as to be pressed down by pressing from the human body H. A convex portion 2 a for pressing the conductive member 5 is formed at the center of the back surface of the input key 2. Further, as shown in FIG. 6, a non-grounded second electrode 4 formed in a flat plate shape so as to cover the convex portion 2a is printed on the back surface of the input key 2. When the human body H approaches the front surface of the input key 2, the input key 2 has a thickness d2 that does not exceed a distance that can change the capacitance C2 of the second electrode 4. Is formed.

  As shown in FIG. 7, an annular first electrode 3 is formed on the insulating substrate 6 so as to face the input key 2 and the second electrode 4. In addition, a contact member 7 formed in a column shape is formed on the substrate 6 and in the center of the annular first electrode 3. As shown in FIGS. 6A and 6B, the contact member 7 is formed through the substrate 6 to the back surface thereof, and the contact member 7 is grounded on the back surface. The contact member 7 is formed so as to be insulated from the first electrode 3.

  As shown in FIG. 7, the conductive member 5 is formed in an inverted dome shape using a conductive metal, and is formed in a ring shape using a conductive fixing means such as soldering. It is fixed along the upper surface side of the electrode 3. In addition, the conductive member 5 is disposed so as to contact the second electrode 4 covering the convex portion 2a of the input key 2 when the input key 2 is not pressed.

  One end of a conducting wire connected to the first electrode 3 is connected to a capacitance detecting means similar to that of the first embodiment for detecting a change in the capacitance C1 of the first electrode 3.

  Next, the operation of the input device 1 according to the third embodiment will be described.

  As shown in FIGS. 4, 6 (a) and 6 (b), the input device 1 of the third embodiment is similar to the input device 1 of the second embodiment, and includes the first electrode 3 and the second electrode 4. The conductive members 5 are disposed so as to contact each other. The input device 1 according to the third embodiment includes an input key 2 that is formed to be freely pressed, and a reverse dome-shaped conductive member that is formed so as to generate a reversal force with respect to the pressing direction of the input key 2. And 5. Therefore, it is possible to give a good click feeling at the time of key input by pressing.

  In addition, the input device 1 of the third embodiment includes a contact member 7 at a position where the input device 2 contacts the second electrode 4 or the conductive member 5 when the input key 2 is pressed. Therefore, when the input key 2 is pressed, the grounded contact member 7 comes into contact with the conductive member 5, and the first electrode 3 is grounded via the contacted conductive member 5. When the first electrode 3 is grounded, the charge of the first electrode 3 becomes 0, so that the clock signal output from the delay means 12 of the capacitance detection means becomes a horizontal line of voltage 0 (see FIG. 3). ). By detecting this, the function of the mechanical contact switch can be added to the function of the proximity switch.

Since the electrostatic capacitance detection means is formed in the same manner as in the second embodiment, its operation is also the same as in the second embodiment.
(4) Fourth Embodiment The input device 1 of the fourth embodiment is used as a two-stage input device such as a shutter switch of a digital camera, like the input device 1 of the third embodiment. As shown in FIGS. 8A and 8B, the input device 1 includes an input key 2, a substrate 6, a first electrode 3, a conductive member 5 also serving as a second electrode 4, a contact member 7, and a first member. 1 is provided with a capacitance detection means (see FIG. 2) for detecting a change in the capacitance C1 of one electrode 3.

  As shown in FIGS. 8A and 8B, the input key 2 is formed so as to be pressed down by pressing from the human body H. A convex portion 2 a for pressing the conductive member 5 is formed at the center of the back surface of the input key 2.

  As shown in FIG. 9, an annular first electrode 3 is formed on the insulating substrate 6 so as to face the input key 2. In addition, a contact member 7 formed in a column shape is formed on the substrate 6 and in the center of the annular first electrode 3. As shown in FIGS. 6A and 6B, the contact member 7 is formed through the substrate 6 to the back surface thereof, and the contact member 7 is grounded on the back surface. The contact member 7 is formed so as to be insulated from the first electrode 3.

  The conductive member 5 is formed using conductive rubber having conductivity and flexibility. A portion of the conductive member 5 facing the substrate 6 is formed in an inverted dome shape as shown in FIG. Further, the portion of the conductive member 5 that faces the input key 2 is formed in a flat plate shape with a relief portion of the convex portion 2 a so as to come into surface contact with the back surface of the input key 2. That is, the inverted dome and the flat plate are integrally formed so that the conductive member 5 plays the role of the second electrode 4. And the circumference | surroundings of the conductive member 5 of the part formed in this inversion dome shape are being fixed to the 1st electrode 3 formed in cyclic | annular form using fixing means, such as a conductive adhesive. In addition, the conductive member 5 is disposed so as to contact the back surface of the input key 2 and its convex portion 2a when the input key 2 is not pressed.

  One end of a conducting wire connected to the first electrode 3 is connected to a capacitance detecting means similar to that of the first embodiment for detecting a change in the capacitance C1 of the first electrode 3.

  Note that the thickness d2 of the input key 2 does not exceed a distance that can change the capacitance C2 of the conductive member 5 serving as the second electrode 4 when the human body H approaches the front surface thereof. It is formed in the thickness.

  Next, the operation of the input device 1 according to the fourth embodiment will be described.

  As shown in FIGS. 8A and 8B, the input device 1 of the fourth embodiment is arranged such that the conductive member 5 that also serves as the second electrode 4 is in contact with the first electrode 3. Yes. The input device 1 according to the fourth embodiment includes an input key 2 that is formed to be freely pressed, and a reverse dome-shaped conductive member that is formed so as to generate a reversal force with respect to the pressing direction of the input key 2. And 5. Therefore, it is possible to give a good click feeling at the time of key input by pressing.

  Further, the input device 1 of the fourth embodiment includes a contact member 7 at a position where the input device 2 comes into contact with the second electrode 4 or the conductive member 5 when the input key 2 is pressed. Therefore, when the input key 2 is pressed, the grounded contact member 7 comes into contact with the conductive member 5, and the first electrode 3 is grounded via the contacted conductive member 5. When the first electrode 3 is grounded, the charge of the first electrode 3 becomes 0, so that the clock signal output from the delay means 12 of the capacitance detection means becomes a horizontal line of voltage 0 (see FIG. 3). ). By detecting this, the function of the mechanical contact switch can be added to the function of the proximity switch.

Since the electrostatic capacitance detection means is formed in the same manner as in the second embodiment, its operation is also the same as in the second embodiment.
(5) Fifth Embodiment As shown in FIG. 10, the input device 1 according to the fifth embodiment is used as an input device such as a cross key. The input device 1 detects changes in the capacitance C1 of the input key 2, the substrate 6, the first electrode 3, the second electrode 4, the dome-shaped conductive member 5, the contact member 7 and the first electrode 3. Electrostatic capacity detecting means (see FIG. 2).

  As shown in FIG. 10, the input key 2 has a cross shape when viewed from the front. As shown in FIG. 11, a columnar support portion 2 b that is elastically deformed is formed at the center of the back surface of the input key 2. That is, the input surfaces 2 c, 2 d, 2 e, 2 f in the cross direction of the input key 2 are formed so as to be pressed by pressing from the human body H. The input surfaces 2c, 2d, 2e, and 2f of the input key 2 have a convex portion 2a for pressing the conductive member 5 at the center of each back surface. Further, as shown in FIG. 11, non-grounded second electrodes 4 each formed in a flat plate shape are printed on the back surfaces of the input surfaces 2c, 2d, 2e, and 2f of the input key 2, respectively. Yes. The second electrode 4 includes the convex portion 2a formed on the back surface of the input surfaces 2c, 2d, 2e, and 2f of the input key 2, and covers the back surface. The thickness d2 of the input key 2 is formed to a thickness that does not exceed the distance that can change the capacitance C2 of the second electrode 4 when the human body H approaches the front surface thereof. Yes.

  As shown in FIG. 11, a plurality of annular first electrodes 3 are formed on the insulating substrate 6 so as to face the input surfaces 2 c, 2 d, 2 e, and 2 f of the input key 2. In addition, a contact member 7 formed in a column shape is formed on the substrate 6 and in the center of the annular first electrode 3. As shown in FIG. 11, the contact member 7 is formed through the substrate 6 to the back surface thereof, and the contact member 7 is grounded on the back surface. The contact member 7 is formed so as to be insulated from the first electrode 3.

  As shown in FIG. 7, the conductive member 5 is formed in an inverted dome shape using a conductive metal, and is formed in a ring shape using a conductive fixing means such as soldering. The electrode 3 is fixed to the upper surface side. In addition, the conductive member 5 is disposed so as to contact the second electrode 4 covering the convex portion 2a of the input key 2 when the input key 2 is not pressed.

  One end of a conducting wire connected to the first electrode 3 is connected to a capacitance detecting means similar to that of the first embodiment for detecting a change in the capacitance C1 of the first electrode 3.

  In the input device 1 of the fifth embodiment formed as described above, a plurality of first electrodes 3 are opposed to a single input key 2. Therefore, it is possible to form a two-stage switch as in the third embodiment for the input key 2 such as a cross key capable of performing a plurality of key inputs.

  As described in the five embodiments as described above, the input device of the present invention can increase the operating distance, so that the allowable range of the thickness of the input key is larger than the conventional one. Play.

  In addition, since the present invention does not require a large design change as compared with the conventional capacitance change type input device, the operation distance can be improved quickly and inexpensively.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed.

Sectional drawing which shows 1st Embodiment of the input device of this invention The circuit diagram which shows an example of the electrostatic capacitance detection means which concerns on this embodiment (A)-(d) is a graph which shows an example of the change of the electrostatic capacitance of the electrode which concerns on this embodiment. Sectional drawing which shows 2nd Embodiment of the input device of this invention The perspective view which shows the whole electrically-conductive member shown in FIG. Sectional drawing which shows 3rd Embodiment of the input device of this invention; (a) is the non-pressing state of an input key, (b) shows the pressing state of an input key The perspective view which shows the inversion dome shape electrically-conductive member shown in FIG. 6, and its periphery Sectional drawing which shows 4th Embodiment of the input device of this invention; (a) is the non-pressing state of an input key, (b) shows the pressing state of an input key The perspective view which shows the electroconductive member integrally formed with the 2nd electrode, and its periphery The perspective view which shows 5th Embodiment of the input device of this invention. Sectional drawing along the 11-11 line of FIG. Sectional drawing which shows an example of the conventional electrostatic capacitance type input device (A) And (b) is sectional drawing which shows another example of the conventional electrostatic capacitance type input device The perspective view which shows the inversion dome shown in FIG. 14 and its periphery

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input device 2 Input key 2a Convex part 2b Support part 2c, 2d, 2e, 2f Input surface 3 1st electrode 4 2nd electrode 5 Conductive member 6 Substrate 7 Contact member 11 Clock signal generation means 12 Delay means 13 Logical product Means 14 Smoothing means 15 A / D conversion means 16 Control unit d1 Distance from the first electrode 3 to the second electrode d2 Distance from the second electrode 4 to the front surface of the input key C1 First electrode 3 and second Capacitance between two electrodes C2 Capacitance between the second electrode 4 and the human body H Human body (finger)

Claims (5)

A first electrode formed on a substrate;
A dielectric input key disposed opposite the first electrode;
A non-grounded second electrode disposed between the first electrode and the front surface of the input key;
A conductive member disposed in contact with each other between the first electrode and the second electrode;
A capacitance detecting means for detecting a change in capacitance of the first electrode;
The input device, wherein the second electrode is disposed at a position where the capacitance of the second electrode changes by a human body approaching the front surface of the input key. The input key is formed to be freely pressed,
The input device according to claim 1 , wherein the conductive member is formed so as to generate a reversal force with respect to a pressing direction of the input key. A contact member insulated from the first electrode and formed on the substrate is disposed at a position in contact with the second electrode or the conductive member when the input key is pressed. The input device according to claim 2 , wherein Said input key is input according to claims 1, characterized in that it is formed integrally so as to cover the opposing position of the first electrode a plurality disposed in any one of claims 3 apparatus. The capacitance detection means includes
Clock signal generating means for generating a clock signal;
Delay means for delaying the clock signal according to the capacitance of the first electrode when a human body approaches or touches the input key;
Logical product means for inputting the clock signal that has been subjected to the delay processing and the clock signal that has not been subjected to the delay processing, and outputting an output signal in accordance with a delay amount of the clock signal that has been subjected to the delay processing;
Smoothing means for smoothing the output signal of the AND means into an analog signal;
A / D conversion means for converting the analog signal into a digital signal;
5. The input device according to claim 1, further comprising: a control unit that detects an input key approached or touched by a human body based on the digital signal.