WO2004061400A1 - 静電容量式センサ - Google Patents
静電容量式センサ Download PDFInfo
- Publication number
- WO2004061400A1 WO2004061400A1 PCT/JP2003/000025 JP0300025W WO2004061400A1 WO 2004061400 A1 WO2004061400 A1 WO 2004061400A1 JP 0300025 W JP0300025 W JP 0300025W WO 2004061400 A1 WO2004061400 A1 WO 2004061400A1
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- WIPO (PCT)
- Prior art keywords
- capacitance
- signal
- electrode
- processing circuit
- signal processing
- Prior art date
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Classifications
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
- G06F3/0338—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
- G01L1/142—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors
- G01L1/144—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors with associated circuitry
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
- G01L5/165—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force using variations in capacitance
Definitions
- the present invention relates to a capacitive sensor suitable for use in performing an operation input in a multidimensional direction.
- Capacitive sensors are used as devices that convert the magnitude and direction of the force applied by an operator into electrical signals.
- a device incorporated as a capacitive sensation sensor for performing multi-dimensional operation input is used.
- an operation amount having a predetermined dynamic range can be input as the magnitude of the force transmitted from the operator. It is also used as a two-dimensional or three-dimensional force sensor that can detect the applied force separately for each direction component.
- a capacitance-type force sensor that forms a capacitance element with two electrodes and detects a force based on a change in capacitance value caused by a change in electrode spacing has a simplified structure. It has been put into practical use in various fields because of its merit that it can reduce costs.
- a capacitance type sensor there is known a sensor having a pair of fixed electrodes for detecting forces in opposite directional components, and a displacement electrode arranged to face these electrodes.
- a capacitance element formed between one fixed electrode and a displacement electrode and the other fixed electrode are used.
- An externally applied force is detected based on a change in the capacitance value of the capacitance element formed between the electrode and the displacement electrode.
- signals are respectively input to the pair of fixed electrodes, and these signals are read by an exclusive-sum circuit or the like after a delay based on a change in the capacitance value of each capacitive element occurs.
- an output signal is derived.
- the sensitivity characteristics of the above-described capacitance type sensor may not be able to sufficiently detect the force of each direction component.
- noise is added to the signal input to each fixed electrode, an erroneous output signal is detected and the sensor malfunctions.
- a main object of the present invention is to provide a capacitance-type sensor that has excellent sensitivity characteristics and is not easily affected by noise. Disclosure of the invention
- the capacitance-type sensor of the present invention includes a conductive member, a capacitor element electrode constituting a first capacitor element between the conductive member, and electrically connected to the conductive member.
- a reference electrode grounded or maintained at a constant potential.
- the capacitance type sensor according to claim 1 is based on that a change in capacitance value of the first capacitance element is detected using a signal input to the first electrode. The force applied from outside can be recognized.
- the capacitance-type sensor according to claim 1 has two pairs of the capacitance element electrodes, and inputs the signals to a circuit including one of the pair of capacitance element electrodes and a circuit including the other. The output signal of the obtained signal is detected by a signal processing circuit having a hysteresis characteristic.
- a signal having hysteresis characteristics In the processing circuit, since the threshold value when the input signal increases and the threshold value when the input signal decreases are different, the change in the output signal corresponding to the change in the capacitance value of the first capacitive element increases. . Accordingly, the sensitivity characteristics as a sensor are improved as compared with the case where the output signal is detected by a signal processing circuit having no hysteresis characteristics.
- the threshold when the input signal increases and the threshold when the input signal decreases are different, so that detection of an erroneous output signal is suppressed. .
- malfunction of the sensor due to the influence of noise can be prevented.
- a second capacitive element may be configured between the reference electrode and the conductive member.
- the conductive member commonly used to configure the first and second capacitive elements is not a direct contact, but is a reference electrode that is held at ground or a fixed potential by capacitive coupling, not by direct contact. Electrically coupled to As a result, the withstand voltage characteristics of the sensor are improved, the sensor is hardly damaged by the flow of spark current, and problems such as poor connection can be prevented. Therefore, a highly reliable capacitive sensor can be obtained.
- the first and second capacitors are connected in series, if the wiring is provided only on a substrate or the like supporting the capacitor electrode and the reference electrode, the conductive member is grounded. Alternatively, there is no need to separately provide a wiring for maintaining a constant potential. Therefore, it is possible to manufacture a capacitance type sensor having a simple structure in a small number of manufacturing steps.
- the capacitance type sensor when defining an XYZ three-dimensional coordinate system, includes a substrate that defines an XY plane, a detection member facing the substrate, the substrate and the detection member. And the detecting member is Z A conductive member that is displaced in the z-axis direction as it is displaced in the axial direction; a capacitive element electrode that is formed on the substrate and that constitutes a first capacitive element with the conductive member; A reference electrode that is formed on the substrate and that is grounded or held at a constant potential that forms a second capacitor between the conductive member and the conductive member.
- the first capacitance element and the second capacitance element are connected in series with respect to a signal input to the capacitance element electrode. And a displacement of the detection member is recognized based on detection of a change in the capacitance value of the first capacitance element caused by a change in the distance between the conductive member and the electrode for the capacitance element. It is possible.
- the capacitance-type sensor according to claim 3 has two pairs of the capacitance element electrodes, and each of the capacitance element electrodes is input to a circuit including one of the pair of capacitance element electrodes and a circuit including the other of the pair. The output signal of the obtained signal is detected by a signal processing circuit having a hysteresis characteristic.
- the output signal is detected by the signal processing circuit having the hysteresis characteristic, so that the output signal is detected by the signal processing circuit having no hysteresis characteristic.
- the sensitivity characteristics as a sensor can be improved. Further, similarly to the second aspect, it is possible to obtain a highly reliable capacitive sensor.
- the capacitance element electrode is arranged symmetrically with respect to the X axis with a pair of first capacitance element electrodes arranged symmetrically with respect to the Y axis. It may have a pair of second capacitance element electrodes provided and a third capacitance element electrode arranged near the origin.
- the third capacitive element electrode recognizes the component in the Z-axis direction. It may be used for input decision operation without using it.
- the signal processing circuit may be such that a threshold value when the input signal increases is larger than a threshold value when the input signal decreases. Further, in the capacitive sensor according to the present invention, the signal processing circuit performs a Schmitt-trigger type logic element that performs any one of an exclusive OR operation, an OR operation, an AND operation, an AND operation, and a NOT operation May be used. In the capacitance type sensor according to the present invention, the signal processing circuit may use a Schmidt-trigger type buffer element. Further, in the capacitive sensor according to the present invention, the signal processing circuit may use a Schmidt's trigger type inverter element. In the capacitance type sensor according to the present invention, the signal processing circuit may use a hysteresis comparator. According to such a configuration, the output signal can be accurately detected, and the detection accuracy or the detection sensitivity can be adjusted as necessary.
- signals having phases different from each other may be supplied to a circuit including one of the pair of electrodes for a capacitive element and a circuit including the other.
- the displacement of the detection member can be recognized regardless of whether the time constant of the circuit including one of the pair of electrodes for the capacitive element and the circuit including the other of the pair are the same.
- the time constant of the CR circuit including one of the pair of electrodes for the capacitive element and the time constant of the CR circuit including the other of the pair may be different. According to such a configuration, the phase shift of a signal caused by passing through the circuit can be increased, and thus the accuracy of the displacement recognition of the detection member can be improved.
- the signal is a high level.
- a control element which is a signal which periodically repeats a single level, and which has a function of discharging the first capacitive element when the signal is at a low level.
- an open collector type inverter element may be used as the control element.
- the electric charge held in the capacitance element is instantaneously discharged by the control element such as the open collector type inverter element. Therefore, charging can be performed efficiently, the density of the signal waveform can be increased, and the sensitivity of the signal processing circuit can be improved.
- FIG. 1 is a schematic sectional view of a capacitance type sensor according to an embodiment of the present invention.
- FIG. 2 is a top view of a detecting member of the capacitance type sensor of FIG.
- FIG. 3 is a diagram showing an arrangement of a plurality of electrodes formed on a substrate of the capacitance type sensor of FIG.
- FIG. 4 is an equivalent circuit diagram for the configuration of the capacitance type sensor shown in FIG.
- FIG. 5 is an explanatory diagram for explaining a method of deriving an output signal from a periodic signal input to the capacitance type sensor shown in FIG.
- FIG. 6 is a schematic cross-sectional view of a side surface when the detection member of the capacitance type sensor shown in FIG. 1 is operated in the positive X-axis direction.
- FIG. 7 is a circuit diagram showing a signal processing circuit of the capacitance type sensor shown in FIG.
- FIG. 8 is a block diagram showing a signal processing circuit of the capacitance type sensor shown in FIG. It is an equivalent circuit diagram.
- FIG. 9 is an equivalent circuit diagram for the signal processing circuit of the capacitance type sensor shown in FIG.
- FIG. 10 is a circuit diagram showing a signal processing circuit for an X-axis direction component of the capacitance type sensor shown in FIG.
- FIG. 11 is a circuit diagram showing a signal processing circuit for comparison with the signal processing circuit shown in FIG.
- FIG. 12 is a diagram showing a waveform of a periodic signal at each terminal and each node of the signal processing circuit shown in FIG. 1.
- FIG. 13 is a diagram showing the relationship between input voltage and output signal on which noise is present.
- FIG. 14 is a diagram showing an arrangement of a plurality of electrodes formed on a substrate of a first modified example of the capacitive sensor of FIG.
- FIG. 15 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a first modification of the capacitance type sensor shown in FIG.
- FIG. 16 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a second modification of the capacitance type sensor shown in FIG.
- FIG. 17 is a diagram showing waveforms of the periodic signal at the terminals and each node of the signal processing circuit shown in FIG. 1 and the signal processing circuit shown in FIG.
- FIG. 18 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a third modification of the capacitance type sensor shown in FIG.
- FIG. 19 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a fourth modification of the capacitance type sensor shown in FIG.
- FIG. 20 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a fifth modification of the capacitive sensor shown in FIG.
- FIG. 21 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a sixth modification of the capacitance type sensor shown in FIG.
- FIG. 22 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a seventh modification of the capacitive sensor shown in FIG. BEST MODE FOR CARRYING OUT THE INVENTION
- FIG. 1 is a schematic sectional view of a capacitance type sensor according to an embodiment of the present invention.
- FIG. 2 is a top view of a detecting member of the capacitance type sensor of FIG.
- FIG. 3 is a diagram showing an arrangement of a plurality of electrodes formed on a substrate of the capacitive sensor of FIG.
- the capacitance type sensor 10 includes a substrate 20, a detection member 30 which is an operation member to which a force is externally applied by being operated by a person or the like, a displacement electrode 40, and a substrate 20.
- a support member 60 for supporting and fixing the detection member 30 and the displacement electrode 40 to the substrate 20.
- an XYZ three-dimensional coordinate system is defined as shown in the figure, and the layout description is made for each component with reference to this coordinate system.
- the origin O is defined at a position facing the center position of the displacement electrode 40 on the substrate 20, the X axis is in the right horizontal direction, the Z axis is in the vertical direction, and the Z axis is in the vertical direction.
- Each Y axis is defined in the depth direction.
- the surface of the substrate 20 defines an XY plane, and The Z axis passes through the respective center positions of the electrode E5, the detecting member 30 and the displacement electrode 40.
- the substrate 20 is a general printed circuit board for electronic circuits, and in this example, a glass epoxy substrate is used. Further, a film-shaped substrate such as polyimide film may be used as the substrate 20. However, a film-shaped substrate has flexibility, and thus is provided on a supporting substrate having sufficient rigidity. It is preferable to use it by arranging it.
- the detecting member 30 is composed of a small-diameter upper portion 31 serving as a receiving portion and a large-diameter lower portion 32 extending to a lower end portion of the upper portion 31, and is formed in a disk shape as a whole.
- the diameter of the upper part 31 is almost the same as or slightly smaller than the diameter of a circle formed by connecting the outer curves of the capacitance element electrodes E1 to E4, and the diameter of the lower part 32 is It is almost the same as the outer diameter of the reference electrode EO.
- the detection member 30 may be covered with a resin cap.
- the upper surface of the upper part 31 of the detecting member 30 is arranged so as to correspond to the positive direction and the negative direction of the X axis and the Y axis, respectively, ⁇ Arrows corresponding to the operation direction (cursor movement direction) are formed to correspond to 1 to ⁇ 4.
- the displacement electrode 40 is formed of conductive rubber, has a disk shape having the same diameter as the lower portion 32 of the detection member 30, and is attached to the lower surface of the detection member 30.
- On the lower surface of the displacement electrode 40 there is formed a concave portion which is circular and opened downward around the center position of the displacement electrode 40. Further, at the bottom of the concave portion, a circular convex portion projecting downward around the center position of the displacement electrode 40 is formed, and the center position of the convex portion (the center position of the displacement electrode 40) is formed at the bottom. A projection 45 is formed.
- the displacement electrode 40 is displaced with the displacement of the detection member 30.
- a connecting portion 42 (a portion other than the convex portion at the bottom of the concave portion formed on the lower surface of the displacement electrode 40) connecting the fixed portion 43 and the fixing portion 43.
- the projection 45 may not be provided, and the displacement electrode 40 may be formed of a conductive metal.
- the displacement electrode 40 can be inclined with the projection 45 as a fulcrum when a force acts on the detection member 30. It is like that. Further, the displacement electrode 40 is detected by the support member 60 so that the lower surface of the fixing portion 43 and the lower surface of the projection 45 are in close contact with the insulating film 50 formed on the substrate 20. It is supported and fixed together with the member 30.
- the projection body 45 has a function of a conductive material that causes the displacement electrode 40 to approach the substrate 20 by receiving a certain amount of force when the detection member 30 is strongly pressed in the Z-axis direction. ing.
- the pair of capacitive element electrodes E1 and E2 are spaced apart in the X-axis direction and arranged symmetrically with respect to the Y-axis.
- the pair of capacitive element electrodes E3 and E4 are spaced apart in the Y-axis direction and arranged symmetrically with respect to the X-axis.
- the reference electrode EO may be formed between the capacitance element electrode E5 and the capacitance element electrodes E1 to E4.
- the capacitor element electrode E5 may be eliminated, and a circular reference electrode E0 centered on the origin O may be formed.
- the Z-axis direction component cannot be detected.
- the capacitor element electrode E1 is arranged so as to correspond to the positive direction of the X-axis.
- the capacitive element electrode E2 is arranged so as to correspond to the negative direction of the X-axis, and is used for detecting the X-axis direction component of the external force.
- the capacitive element electrode E 3 is arranged so as to correspond to the positive direction of the Y axis, while the capacitive element electrode E 4 is arranged so as to correspond to the negative direction of the Y axis. Used for detecting the Y-axis direction component.
- the capacitive element electrode E5 is arranged on the origin O, and is used for detecting a component of the external force in the Z-axis direction.
- the electrodes E 1 to E 5 for the capacitive element and the reference electrode E 0 are connected to terminals TO to T 5 (see FIG. 4) using through holes or the like, respectively. Through to an external electronic circuit.
- the reference electrode ⁇ 0 is grounded via the terminal T O.
- the insulating film 50 is formed so as to be in close contact with the capacitance element electrodes E1 to E5 and the reference electrode E0 on the substrate 20 so as to cover the substrate 20. Therefore, the capacitance element electrodes E1 to E5 and the reference electrode E0 formed of copper or the like are not exposed to air, and have a function of preventing them from being oxidized. In addition, since the insulating film 50 is formed, the displacement electrodes 40 do not directly contact the capacitance element electrodes E1 to E5 and the reference electrode E0.
- the capacitance element electrodes E1 to E5 and the reference electrode E0 each constitute a capacitance element with the displacement electrode 40.
- the electrodes E 1 to E 5 for the capacitance element constitute capacitance elements C 1 to C 5 respectively with the displacement part 41 of the displacement electrode 40, and the reference electrode E 0 is the displacement electrode 40.
- a capacitance element C0 is formed with the fixed part 43 of the capacitor.
- FIG. 3 is an equivalent circuit diagram for the configuration of the capacitance type sensor shown in FIG.
- FIG. 5 is an explanatory diagram for explaining a method of deriving an output signal from a periodic signal input to the capacitance type sensor shown in FIG.
- FIG. 6 is a schematic cross-sectional view of a side surface when the detection member of the capacitance-type sensor shown in FIG. 1 is operated in the positive direction of the X-axis.
- each of the capacitance elements C1 to C5 is a variable capacitance element configured to change the capacitance value due to the displacement of the displacement electrode 40.
- each of the capacitance elements CO to C5 is between the displacement electrode 40 and the terminals TO to T5 connected to the capacitance element electrodes E1 to E5 and the reference electrode E0, respectively.
- Each can be measured independently as a capacitance value.
- the reference electrode ⁇ ⁇ is grounded via the terminal TO
- the displacement electrode 40 which is a common electrode in the capacitance elements C1 to C5 is grounded via the capacitance element C0 and the terminal T0. It is considered that it has been done. That is, the capacitive element C O capacitively couples the displacement electrode 40 and the terminal T 0.
- the output signals V x, V y, and V z indicate the magnitude and direction of the X-axis component, the Y-axis component, and the Z-axis component of the external force, respectively.
- the output signal V x, Vy, and Vz indicate that they are output from the Schmitt-trigger type logic element included in the signal processing circuit having the hysteresis characteristic.Therefore, the symbol of the logic element has a symbolized hysteresis characteristic. Is drawn.
- the capacitive element C 6 shown in FIG. 5 is formed on the lower surface of the substrate 20 so as to always maintain a constant capacitance value, and one of the electrodes constituting the capacitive element C 6 has an output signal V Derived z is connected to the C / V conversion circuit, and the other electrode is grounded.
- the capacitive element C6 is used together with the capacitive element C5 to derive an output signal Vz of a Z-axis direction component of an external force.
- an input capacitance of I C can be used as the capacitance element C 6.
- a stable capacitive element C6 may be formed by a portion of the displacement electrode 40 that is not easily displaced between the sixth electrode E6 and the displacement electrode 40 (not shown).
- a periodic signal such as a clock signal is always input to the terminals T1 to ⁇ 6.
- two capacitors C1 and CO are connected in series.
- two capacitors C 2 and C 0 are connected in series with the periodic signal input to terminal T 2
- two capacitors C 3 and CO are input to terminal T 3
- the two capacitors C 4 and C 0 are connected in series with the periodic signal input to the terminal T 4.
- the two capacitors C5 and C0 are connected in series with the periodic signal input to the terminal T5.
- the displacement electrode 40 When the detection member 30 is displaced by receiving an external force in a state where a periodic signal is input to the terminals T1 to T6, the displacement electrode 40 is displaced in the ⁇ -axis direction accordingly, and the capacitance element C The electrode spacing of 1 to C5 changes, and the capacitance value of each of the capacitance elements C1 to C5 changes. Then, terminal T The phase of the periodic signal input to 1 to T6 is shifted. In this way, by utilizing the phase shift generated in the periodic signal, the displacement of the detection member 30, that is, the magnitude of the force applied externally by the detection member 30 in the X-axis direction, the ⁇ -axis direction, and the ⁇ -axis direction is determined. It is possible to obtain output signals Vx, Vy, Vz indicating the directions.
- a periodic signal is input to the terminals T1 to T6, a periodic signal ⁇ is input to the terminals Tl, ⁇ 3, and ⁇ 5, while a periodic signal ⁇ is input to the terminals T2, ⁇ 4.
- ⁇ 6 a periodic signal B having the same period as the periodic signal ⁇ and having a phase different from that of the periodic signal A is input.
- the detecting member 30 receives an external force and the capacitance values of the capacitive elements C1 to C5 change respectively, the periodic signal ⁇ or the periodic signal input to the terminals T1 to T5 respectively.
- a different amount of shift occurs in the phase of ⁇ . Since the capacitance value of the capacitance element C 6 does not change, the phase of the periodic signal B input to the terminal T 6 does not shift.
- the capacitance value of the capacitor C 1 changes, and the phase of the periodic signal A input to the terminal T 1 shifts, and The capacitance value of the capacitance element C2 changes, and the phase of the periodic signal B input to the terminal T2 shifts.
- the changes in the capacitance values of the capacitance elements C l and C 2 correspond to the X-axis direction components of the external force, respectively. Therefore, the phase shift of the periodic signal A input to the terminal T1 and the phase shift of the periodic signal B input to the terminal T2 are opposite phase shifts.
- the output signal VX is derived by reading the phase shift of the periodic signal A and the periodic signal B input to the terminal T 1 and the terminal T 2, respectively, using the exclusive-sum circuit.
- the sign of the change in the output signal V x indicates whether the X-axis component of the external force is in the positive or negative direction.
- the absolute value indicates the magnitude of the X-axis component.
- the capacitance value of the capacitive element C 3 changes, and the phase of the periodic signal A input to the terminal T 3 shifts.
- the capacitance value of C4 changes, and the phase of the periodic signal B input to the terminal T4 shifts.
- the changes in the capacitance values of the capacitance elements C 3 and C 4 respectively correspond to the Y-axis component of the external force. Therefore, the phase shift of the periodic signal A input to the terminal T3 and the phase shift of the periodic signal B input to the terminal T4 are opposite to each other.
- the output signal Vy is derived by reading the phase shift of the periodic signal A and the periodic signal B input to the terminal T3 and the terminal T4, respectively, by using the exclusive-sum circuit.
- the sign of the change in the output signal V y indicates whether the Y-axis component of the external force is in the positive or negative direction, and the absolute value of the change in the output signal V y is the magnitude of the Y-axis component. Is shown.
- the capacitance value of the capacitive element C5 changes, and the phase of the periodic signal A input to the terminal T5 shifts. Further, since the capacitance value of the capacitance element C6 is kept constant, the phase of the periodic signal B input to the terminal T6 does not shift. Accordingly, a phase shift occurs only in the periodic signal A input to the terminal T5, and the output signal Vz is derived by reading the phase shift of the periodic signal A by the exclusive-sum circuit.
- the sign of the change in the output signal Vz indicates whether the Z-axis component of the external force is in the positive or negative direction, and the absolute value of the change in the output signal Vz is the Z-axis component. Indicates the size.
- the external force includes the X-axis direction component or the Y-axis direction component
- the following cases may be considered depending on how the force is applied to the detection member 30.
- displacement The X-axis positive direction portion and the X-axis negative direction portion of the portion 41 are not displaced up and down with respect to each other with the protrusion 45 as a fulcrum. It may be displaced downward, and the amount of displacement at that time may be different.
- the phases of the periodic signal A and the periodic signal B input to the terminals T1 and T2 are shifted in the same direction.
- the output signal VX is derived by reading the deviation with an exclusive-sum circuit. The same can be said for the derivation of the output signal Vy in the Y-axis direction.
- the connecting portion 42 of the displacement electrode 40 is elastically deformed and bent, and the positive portion of the displacement portion 41 in the X-axis direction is downward.
- the displacement portion 41 is displaced to a position where the lower surface of the X-axis positive direction portion contacts the insulating film 50.
- the X-axis positive direction portion and the X-axis negative direction portion of the displacement portion 41 are displaced vertically opposite to each other with the protrusion 45 as a fulcrum. Therefore, when the X-axis positive direction portion of the displacement portion 41 is displaced downward, the X-axis negative direction portion of the displacement portion 41 is displaced upward with the protrusion 45 as a fulcrum.
- the positive side of the displacement portion 41 in the positive direction of the X axis is slightly displaced downward and the negative side of the X axis is slightly displaced upward.
- the negative side of the Y axis is slightly displaced downward on the positive side of the X axis, and slightly displaced upward on the negative side of the X axis. I do.
- the protrusion 45 formed at the center position (on the Z axis) of the displacement portion 41 is crushed and elastically deformed.
- the distance between the positive portion of the displacement portion 41 in the X-axis direction and the electrode E 1 for the capacitance element becomes small, while the distance between the negative direction of the X axis of the displacement portion 41 and the electrode E 2 for the capacitance element becomes large.
- the distance between the positive portion of the displacement portion 41 in the Y-axis direction and the capacitor electrode E3 and the distance between the negative portion of the displacement portion 41 in the Y-axis direction and the capacitor electrode E4 change on average. It is considered not to be.
- the positive and negative X-axis portions of the displacement portion 41 slightly displace downward on the positive X-axis side and slightly displace upward on the negative X-axis portion.
- the distance between the capacitive element electrodes E3 and E4 as the whole of the Y-axis positive direction part and the Y-axis negative direction part of the displacement part 41 does not change.
- the distance between the Y-axis positive direction portion of the displacement portion 41 and the capacitance element electrode E3 and the distance between the Y-axis negative direction portion of the displacement portion 41 and the capacitance element electrode E4 are partially changed.
- the capacitance value of the capacitance element C 3 and the displacement part 4 formed between the positive part of the displacement part 41 1 in the Y-axis direction and the capacitance element electrode E 3 It is considered that the amount of change in the capacitance value of the capacitance element C4 formed between the Y-axis negative direction part 1 and the capacitance element electrode E4 is equal, and does not appear in the output due to the operation principle. In addition, the distance between the center position of the displacement part 41 and the capacitor electrode E5 becomes small.
- the capacitance value of the capacitance element is inversely proportional to the distance between the electrodes constituting the capacitance element, the capacitance value of the capacitance element C1 increases, and the capacitance value of the capacitance element C2 increases. The capacitance value decreases. That is, the capacitance value of each of the capacitance elements C1 to C4
- the magnitude relation of is as follows.
- the phases of the periodic signal A and the periodic signal B input to the terminals T1 and T2 are shifted, and the output signal Vx is derived by reading the phase shift.
- the phase of the periodic signal A input to the terminal T5 is shifted, and by reading the phase shift (actually together with the phase of the periodic signal B input to the terminal T6), An output signal Vz is derived.
- FIG. 7 is a circuit diagram showing a signal processing circuit of the capacitance type sensor shown in FIG. 8 and 9 are circuit diagrams showing a signal processing circuit equivalent to the signal processing circuit of the capacitance type sensor shown in FIG.
- a periodic signal having a predetermined frequency is input to the terminals T1 to T6 from an AC signal oscillator (not shown).
- These terminals ⁇ 1 to ⁇ 6 include inverter elements I 1 to 16 and resistance elements R 1 to R 6, and inverter elements I 1 to I 6 and resistance elements R 1 to R 6 from terminals T 1 to T 6. They are connected in the order of R 6.
- the output terminals of the resistive elements Rl and R2, the output terminals of the resistive elements R3 and R4, and the output terminals of the resistive elements R5 and R6 are connected to the logic of a Schmitt-trigger exclusive OR circuit, respectively.
- An EX-OR element 101 to 103 which is an element, is connected, and its output terminal is connected to terminals T11 to T13.
- the output terminals of the resistance elements R1 to R5 are connected to the capacitance element electrodes E1 to E5, respectively, and constitute the capacitance elements C1 to C5 with the displacement electrodes 40, respectively.
- displacement electrode 40 is grounded via a capacitive element CO.
- FIGS. 10 (a) and 10 (b) are circuit diagrams (parts of FIG. 8) showing a signal processing circuit for the X-axis component of the capacitive sensor shown in FIG. Since the circuit diagrams of the signal processing circuits shown in FIGS. 7 to 9 are all equivalent, the description will be given here based on FIG.
- the capacitance element C1 and the resistance element R1 and the capacitance element C2 and the resistance element R2 form a CR delay circuit.
- the periodic signals (square wave signals) input to the terminals Tl and ⁇ 2 are delayed by the CR delay circuit, and are passed through the shunt. — Merge at OR element 13 1.
- the inverter elements I 1 and I 2 are elements that generate sufficient driving power to drive the CR delay circuit, and are logically meaningless elements.
- FIG. 10 (b) does not include the inverter elements I1 and 12 included in the signal processing circuit of FIG. 10 (a), and the circuit is completely equivalent to FIG. 10 (a). It is considered something.
- FIG. 11 is a circuit diagram showing a signal processing circuit for comparison with the signal processing circuit shown in FIG.
- FIG. 12 is a diagram showing a waveform of a periodic signal at each terminal and each node of the signal processing circuit shown in FIG. 10 and FIG.
- the periodic signals input to each of the terminals Tl and ⁇ 2 pass through the CR delay circuit, thereby causing a predetermined delay, respectively.
- the Schmidt-trigger type buffer element 1 1 1 and 1 1 2 After passing through the Schmidt-trigger type buffer element 1 1 1 and 1 1 2, it is input to the OR-OR element 13 1.
- a periodic signal f () (corresponding to the above-described periodic signal A, hereinafter referred to as a periodic signal A) is input to a terminal T 1
- f () is input to a terminal T 2.
- a periodic signal f ( ⁇ - ⁇ ) (corresponding to the above-described periodic signal B and hereinafter referred to as a periodic signal B) having the same period and a phase shift of 0 is input.
- the periodic signals ⁇ ⁇ ⁇ and ⁇ having different phases respectively input to the terminals T l and ⁇ 2 are obtained by dividing the periodic signal output from one AC signal oscillator into two paths, This is generated by providing a CR delay circuit (not shown) and delaying the phase of the periodic signal passing through the CR delay circuit.
- the method of shifting the phase of the periodic signal is not limited to the method using the CR delay circuit, but may be any other method, or using two AC signal oscillators having different phases.
- the periodic signal A and the periodic signal B may be generated and input to each of the terminals Tl and ⁇ ⁇ ⁇ ⁇ 2.
- the periodic signal ⁇ and the periodic signal ⁇ ⁇ input to the terminals Tl and ⁇ 2 are a delay circuit or a capacitive element C composed of the capacitive element C1 and the resistive element R1. 2 and the resistance element R 2, the delay is made by passing through the delay circuit, and reaches the nodes XI 1 and XI 2, respectively.
- the capacitance values of the capacitance elements C 1 and C 2 in a state where no external force is applied to the detecting member 30 (no operation is performed) are as follows. This is a capacitance value based on the distance between the displacement electrode 40 and the capacitance element electrodes E 1 and E 2 in a state where no electrode exists.
- FIG. 12 (C) shows the change in the potential at the node XI 1 of the signal processing circuit shown in FIG. 10 (b), and FIG. 12 (d) shows the change in the potential in FIG. 10 (b).
- 5 shows a change in potential at a node X12 of the signal processing circuit shown in FIG.
- FIG. 12 (e) shows the waveform of the periodic signal at node X13 of the signal processing circuit shown in FIG. 10 (b)
- FIG. 12 (f) shows the waveform of the first signal.
- 0 shows the waveform of the periodic signal at node XI 4 of the signal processing circuit shown in FIG.
- the threshold voltage when the input voltage increases hereinafter referred to as the positive threshold voltage Vp
- the threshold voltage when the input voltage decreases hereinafter the threshold voltage.
- a negative threshold voltage Vn the threshold voltage when the input voltage increases
- two threshold voltages of a positive threshold voltage V and a negative threshold voltage Vn that is smaller than the positive threshold voltage Vp are set.
- the output signal is switched from the “Lo” signal to the “Hi” signal, while the input voltage decreases while the input voltage decreases.
- Negative thread When the voltage becomes lower than the threshold voltage Vn, the output signal is switched from the “Hi” signal to the “Lo” signal.
- FIG. 13 is a diagram showing a relationship between an input voltage on which noise is present and an output signal.
- the input voltage temporarily becomes larger than the positive threshold voltage Vp at time Ta. Thereafter, the input voltage becomes smaller than the positive threshold voltage Vp at time Tb, and becomes larger than the positive threshold voltage Vp again at time Tc.
- the output signal is switched from the “Lo” signal to the “Hi” signal at time Ta. Then, the input voltage becomes smaller than the positive threshold voltage Vp at time Tb, but does not become smaller than the negative threshold voltage Vn, so that the output signal is switched from the signal of ⁇ Hi '' to the signal of ⁇ Lo ''. There is no. Therefore, at times Tb and Tc, the output signal of “H i” is continued.
- the input voltage on which the noise is present decreases, the input voltage becomes smaller than the negative threshold voltage Vn at time Td. Thereafter, the input voltage becomes larger than the negative threshold voltage Vn at the time Te, and becomes smaller than the negative threshold voltage Vn again at the time Tf.
- the output signal is switched from the “Hi” signal to the “Lo” signal at time Td. Then, the input voltage becomes larger than the negative threshold voltage Vn at the time T e, but does not become larger than the positive threshold voltage Vp. There is no. Therefore, at time Te and Tf, the output signal of “L o” is To be continued.
- the positive threshold voltage V is usually a value between VccZ2 and Vcc.
- the negative threshold voltage Vn is a value between 0 and Vcc / 2.
- General Schmitt ⁇ In the trigger type buffer element, when the power supply voltage Vcc is 4.5V, the positive threshold voltage Vp is 2.7V and the negative threshold voltage Vn is 1.6V. As described later, the threshold voltage of the C-MOS type logic element is generally about VccZ2.
- the square wave at the node X13 (see FIG. 12 (e)) and the square wave at the node XI4 (see FIG. 12 (f)) are input to the EX-OR element 131. An exclusive logical operation is performed between these signals, and the result is output to terminal T11.
- the output signal Vx output to the terminal T11 is a rectangular wave signal having a duty ratio D1, as shown in FIG. 12 (g).
- a delay circuit composed of the capacitive element C1 and the resistive element R1 of the periodic signal ⁇ and the periodic signal B input to the terminals Tl and ⁇ 2, or the capacitive element C2 and the resistive element R The amount of delay caused by passing through the delay circuit composed of 2 changes.
- the periodic signal ⁇ and the periodic signal ⁇ ⁇ input to the terminals T l and ⁇ 2 are the capacitances of the capacitance elements C l and C 2 when the capacitance values are changed. Delays by passing through a delay circuit composed of element C 1 and resistance element R 1 or a delay circuit composed of capacitance element C 2 and resistance element R 2 and reaches nodes XI 1 'and XI 2', respectively I do.
- the detection unit 30 is operated in the positive direction of the X-axis, the nodes XI and X12 at the same position as the nodes X11 and X12 of the signal processing circuit shown in FIG. Shown as 1 ', XI 2'.
- FIG. 12 (h) shows the change in the potential at the node X11 ′ of the signal processing circuit shown in FIG. 10 (b), and FIG. 12 (i) The potential change at node X12, in the signal processing circuit shown in Fig. 10 (b) is shown.
- the waveforms of the potentials at the nodes XI 1 ′ and XI 2 respectively show the Schmitt-trigger type buffer elements 1 1 1 and 1 1 It is converted into a square wave by inputting it to 1 1 2.
- the converted square wave is input to the EX-OR element 13 1, an exclusive logical operation is performed between these signals, and the result is output to the terminal T 11.
- the output signal Vx output to the terminal Tl1 is a rectangular wave signal having a duty ratio D2 as shown in FIG. 12 (j).
- a signal processing circuit having no hysteresis characteristics that is, as shown in FIG. 11, FIG.
- the waveform of the periodic signal at each terminal and each node when the signal processing circuit removed from the toe-trigger-type buffer elements 111 and 112 is used will be described.
- the Schmitt-trigger type buffer element 1 1 1 and 1 1 2 has two different threshold voltages, while only one threshold voltage is set. Then, when the input voltage becomes higher than the threshold voltage, the output signal is switched from the “Lo” signal to the “Hi” signal, while the input voltage becomes lower than the threshold voltage. In this case, the output signal is converted to a square wave signal by switching from the “Hi” signal to the “Lo” signal.
- the threshold voltage is often set to about Vcc / 2.
- the periodic signal A and the periodic signal B input to the terminals T 1 and T 2 are such that no external force acts on the detecting member 30 (no operation is performed).
- each node is delayed by passing through a delay circuit composed of the capacitance element C1 and the resistance element R1 or a delay circuit composed of the capacitance element C2 and the resistance element R2.
- X2 1, reach X22.
- the changes in the potentials at the nodes X21 and X22 of the signal processing circuit shown in FIG. 11 at this time are the same as those in FIGS. 12 (c) and (d).
- the waveform of the potential at the nodes X 21 and X 22 is input to the EX-OR element 131.
- the potential waveforms at the nodes X21 and X22 are converted into rectangular waves as described above, an exclusive logical operation is performed between these signals, and the result is output to the terminal T11. Be done .
- the output signal Vx output to the terminal Tl1 is a rectangular wave signal having a duty ratio D3 as shown in FIG. 12 (k).
- FIG. 6 a case where the detection member 30 is operated in the X-axis positive direction will be considered.
- the capacitance values of the capacitance elements C1 and C2 change as described above.
- the periodic signal ⁇ and the periodic signal ⁇ ⁇ input to the terminals T l and ⁇ 2 are the capacitance elements when the capacitance values of the capacitance elements C l and C 2 are changed. Delayed by passing through a delay circuit composed of C1 and a resistance element R1 or a delay circuit composed of a capacitance element C2 and a resistance element R2, the signals were respectively added to nodes X21 'and X22'. To reach. When the detection member 30 is operated in the positive X-axis direction, the nodes X21 'and X22 are set to the same positions as the nodes X21 and X22 of the signal processing circuit shown in FIG. '.
- the EX-OR element 131 receives the waveforms at the nodes X11, XI2 ', converts them into rectangular waves, and performs an exclusive logical operation between these signals. The result is output to terminal T11.
- the output signal Vx output to the terminal T11 is a rectangular wave signal having a duty ratio D4 as shown in FIG. 12 (1).
- the detection member 30 When the detection member 30 is operated in the positive direction of the X-axis from a state where no external force is applied to the outside, the duty ratio of the output signal Vx output to the terminal Tl 1 is changed from D 1 Change to D2.
- a signal processing circuit without hysteresis characteristics see Fig.
- the detection member 30 When the detection member 30 is operated in the positive direction of the X-axis from a state in which no external force is applied to the sensor, the duty ratio of the output signal Vx output to the terminal T11 becomes D Changes from 3 to D4.
- the change amount between the duty ratio D3 of the square wave signal of k) and the duty ratio D4 of the square wave signal of FIG. 12 (1) is larger.
- the output signal Vx output to the terminal Tl1 is often converted to an analog voltage and used. Therefore, when the output signal Vx is converted to an analog voltage, the amount of change in the duty ratio between the two rectangular wave signals is integrated.
- a signal processing circuit having a hysteresis characteristic see FIG. 10 (b)
- a signal processing circuit having no hysteresis characteristic see FIG.
- the sensitivity characteristics of the sensor can be improved as compared with the case where (see Fig. 11) is used.
- the capacitance type sensor 10 of the present embodiment uses a signal processing circuit having a hysteresis characteristic as a signal processing circuit
- the capacitance sensor 10 has a positive threshold voltage V p when the input voltage increases.
- the negative threshold voltage Vn when the input voltage decreases is different. Therefore, the amount of change in the duty ratio of the output signal when detected by a signal processing circuit having hysteresis characteristics is the change in the duty ratio of the output signal when detected by a signal processing circuit without hysteresis characteristics. Larger than the quantity. This improves the sensitivity characteristics of the sensor.
- the threshold when the input voltage increases and the threshold when the input voltage decreases differs. Therefore, detection of an erroneous output signal is suppressed. Thereby, malfunction of the sensor due to the influence of noise can be prevented.
- the displacement electrode 40 commonly used to form the plurality of capacitive elements C0 to C5 is electrically coupled to the reference electrode E0 that is grounded or held at a fixed potential, via a capacitive coupling.
- the direct connection with the reference electrode E 0 eliminates the need for electrical connection.
- the withstand voltage characteristics of the sensor are improved, damage due to the flow of spark current is almost eliminated, and failures such as poor connection can be prevented, resulting in high reliability! / Capacitive sensor can be obtained.
- the capacitive elements C1, C0; C2, CO; ...; C5, C0 are connected in series with the periodic signal, the capacitive element electrode and the reference electrode are supported.
- the wiring is provided only on the substrate 20 to be replaced, it is not necessary to provide the wiring for holding the displacement electrode 40 at the ground or at a constant potential. Therefore, it is possible to manufacture a capacitance type sensor having a simple structure in a small number of manufacturing steps.
- a plurality of capacitive element electrodes E1 to E5 are formed, and the detecting member 30 can separately recognize the directional components of the force received from the outside in the X-axis direction, the Y-axis direction, and the Z-axis direction. it can.
- signals having phases different from each other are supplied to the pair of capacitance element electrodes (£ 1, £ 2, £ 3, £ 4). The phase shift can be increased, and the signal can be detected with high accuracy because a signal processing circuit using a logic element is used.
- FIG. 14 is a diagram showing an arrangement of a plurality of electrodes formed on a substrate of a capacitive sensor according to a first modification.
- the capacitance type sensor according to the first modified example is the capacitance type sensor shown in FIG.
- the configuration of the reference electrode E0 on the substrate 20 in the semiconductor device is changed, and reference electrodes EO1 to EO4 are formed as shown in FIG.
- Other configurations are the same as those of the capacitance type sensor of FIG. 1, and therefore, the same reference numerals are given and the description is omitted.
- FIG. 14 shows the X of the capacitance type sensor according to the first modification.
- FIG. 15 shows the X of the capacitance type sensor according to the first modification.
- FIG. 3 is a circuit diagram illustrating a signal processing circuit for an axial component.
- the difference between the signal processing circuit of FIG. 15 and the signal processing circuit of the capacitance type sensor of FIG. 1 is that the reference electrodes E 01 and E 02 on the substrate 20 are the capacitive element electrodes E The point is that they are formed separately for each of E1 and E2. For this reason, the displacement electrodes 40 are separately grounded via the capacitive elements C 01 and C 02. The same applies to the detection of the Y-axis direction component.
- the capacitance element electrodes E1 to E4 are arranged so as to be surrounded by the reference electrodes EO1 to ⁇ 4.
- the reference electrode is divided into four.
- the reference electrode may be divided in any number, shape, and arrangement. It can be changed as appropriate in consideration of the wiring arrangement.
- FIG. 16 is a circuit diagram showing a signal processing circuit for an X-axis direction component of the capacitive sensor according to the second modification.
- the signal processing circuit of FIG. 16 differs from the signal processing circuit of the capacitance type sensor of FIG. 1 in that an open collector type between the terminal T 1 and the resistor R 1 and the capacitor C 1 is provided.
- An inverter element 91 is arranged.
- an open-collector type inverter element 92 is arranged between the terminal T2 and the resistance element R2 and the capacitance element C2.
- R2 is that the potential on the opposite side to the one connected to the terminals T1, T2 is kept at a constant potential Vcc.
- the open-collector type inverter elements 91 and 92 are in the state of the input terminal of the EX-OR element when the signal that periodically repeats the high level and the low level input to the capacitor electrode is at the high level. This is a control element that has the function of discharging the capacitive element when it is at the low level, but does not affect the capacitance.
- nodes X 11 and XI 2 of the signal processing circuit shown in FIG. 10 (b) and a signal processing circuit shown in FIG. 16 when a periodic signal is input to terminals T l and ⁇ 2 The change in the potential at the nodes X31 and X32 will be described with reference to FIG. Here, only the change in potential at the nodes XII and X31 will be described.
- the potential at the node X 31 gradually increases when the input of the signal of “Hi” starts, because the charge is gradually stored in the capacitor C 1 constituting the CR delay circuit, and the potential of “Lo”
- the charge of the capacitive element C 1 constituting the CR delay circuit is instantaneously discharged via the open-collector type inverter element 91, and the instantaneous decrease is repeated.
- the signal processing circuit shown in the figure can reduce the period of the periodic signal and increase the waveform density compared to the signal processing circuit in FIG. 10 (b), thereby improving the sensitivity of the signal processing circuit. it can.
- FIG. 18 is a circuit diagram showing a signal processing circuit for an X-axis direction component of the capacitance type sensor according to the third modification.
- the signal processing circuit of FIG. 18 differs from the signal processing circuit of the capacitive sensor of FIG. 1 in that a ⁇ R element is used instead of an EX-OR element as a logic element. is there.
- the other configuration is the same as that of the capacitance type sensor shown in FIG.
- the periodic signal A input to the terminal T1 passes through the CR delay circuit composed of the capacitor C1 and the resistor R1, and reaches the node XI1.
- a predetermined delay occurs in the periodic signal at the node XI1, as shown in FIG.
- the periodic signal B input to the terminal T12 is composed of the capacitance element C2 and the resistance element R2. After passing through the CR delay circuit to be formed, it reaches node XI2.
- a predetermined delay occurs in the periodic signal at the node 12. Therefore, as in Fig. 10 (b), the periodic signal at the nodes X11 and X12 is transmitted to the OR element 1334 through the trigger type buffer elements 111 and 112.
- the converted signal is input, an OR operation is performed between these signals, and the result is output to the terminal T11.
- the signal output to the terminal 11 is a rectangular wave signal having a predetermined duty ratio.
- the amount of change in the duty ratio with the wave signal is smaller than that of the rectangular wave signal output to the terminal 11 when the EX_OR element 13 is used. For this reason, it is considered that the sensitivity characteristics of the capacitance type sensor deteriorate.
- FIG. 19 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a capacitive sensor according to a fourth modification.
- the signal processing circuit of Fig. 19 differs from the signal processing circuit of the capacitive sensor of Fig. 1 in that an AND element is used instead of an EX-OR element as a logic element. is there.
- Other configurations are the same as those of the capacitance type sensor shown in FIG.
- the periodic signal A input to the terminal T1 passes through the CR delay circuit composed of the capacitor C1 and the resistor R1, and reaches the node XI1. At this time, a predetermined delay occurs in the periodic signal at the node XI1, as shown in FIG.
- the periodic signal B input to the terminal T12 passes through the CR delay circuit composed of the capacitor C2 and the resistor R2, and reaches the node XI2. At this time, a predetermined delay occurs in the periodic signal at the node 12. Therefore, as in Fig.
- the AND element 1335 must have the periodic signals at nodes XI1 and XI2 passing through the Schmitt-trigger buffer elements 1 1 1 and 1 1 2
- the signal converted by is input, an AND operation is performed between these signals, and the result is output to the terminal T11.
- the signal output to the terminal 11 is a rectangular wave signal having a predetermined duty ratio.
- the sensitivity of the capacitive sensor is determined by the configuration of the signal processing circuit. It is preferably used to adjust the characteristics (here, lower the sensitivity characteristics).
- FIG. 20 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a capacitive sensor according to a fifth modification.
- This signal processing circuit differs from the signal processing circuit of the capacitive sensor of FIG. 1 in that a NAND element is used as a logic element instead of an EX-OR element.
- Other configurations are the same as those of the capacitance type sensor shown in FIG. 1, and therefore, the same reference numerals are given and the description is omitted.
- the periodic signal A input to the terminal T 1 passes through the CR delay circuit composed of the capacitor C 1 and the resistor R 1 and reaches the node X 11.
- the periodic signal at the node X11 has a predetermined delay as shown in FIG.
- the periodic signal B input to the terminal T12 passes through the CR delay circuit composed of the capacitance element C2 and the resistance element R2, and reaches the node X12.
- the periodic signal at the node 12 has a predetermined delay. Therefore, as in FIG. 10 (b), the NAND element 136 has the node X 1
- the periodic signal at I, X12 is Schmidt '' Trigger type buffer element 1
- I The signal converted by passing through I, 1 1 and 2 is input, a logical product operation is performed between these signals, and then a negative operation is performed.
- the signal output to the terminal 11 is a rectangular wave signal having a predetermined duty ratio.
- each member of the capacitance type sensor is made of a material having a very good sensitivity characteristic when used as a capacitance type sensor, a signal processing is performed. It is preferably used to adjust the sensitivity characteristic of the capacitive sensor (in this case, decrease the sensitivity characteristic) depending on the configuration of the physical circuit.
- FIG. 21 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a capacitance type sensor according to a sixth modification.
- the difference between the signal processing circuit of Fig. 21 and the signal processing circuit of the capacitive sensor of Fig. 1 is that the hysteresis comparators 141 and 142 are used instead of the Schmidt's trigger type buffer elements 1 1 1 and 1 1 2. This is the point used.
- Other configurations are the same as those of the capacitance type sensor of FIG. 1, and therefore, the same reference numerals are given and the description is omitted.
- the hysteresis comparators 141 and 142 are composed of comparators 141a and 142a, variable resistors Rf1 and Rf2, reference voltages 141b and 142b, and resistance elements Rc1 and Rc2, respectively. It is composed of Resistors (pull-up resistors) Rp1 and Rp2 are connected to the output terminals of the comparators 141a and 142a, respectively. The potential on the opposite side of the output terminal is kept at a constant potential Vcc.
- the output terminal of the resistance element R c1 is connected to one input terminal of the comparator 141a, and the reference voltage 141b is connected to the other input terminal. Therefore, a node X 141 between the comparator 141a and the reference voltage 141b is maintained at a predetermined potential.
- the output terminal of the gomperator 14 1 a is connected to the input terminal of the EX-OR element 13 1.
- the node between one input terminal of the comparator 141a and the output terminal of the resistance element Rc1 and the node between the output terminal of the comparator 141a and the EX-OR element 131 are a variable resistor. Connected via R f 1.
- the output terminal of the comparator 141a and the EX-OR element 13 1 The node between them is connected to the resistance element R p 1, and the output from the comparator 144 a is pulled up.
- the configuration of the hysteresis comparator 1442 is the same as the configuration of the hysteresis comparator 1441, and a description thereof will be omitted.
- the resistance value of the variable resistor R f 1 included in the hysteresis comparator 14 1 is R f
- the resistance value of the resistance element R c 1 is R c
- the voltage value of the reference voltage 14 4 b is Vref.
- V U V CC ⁇ -Rf
- the power supply voltage Vcc is 5 V
- the reference voltage 14 1 b is 2.5 V
- the resistance value R c of the resistance element R c 1 is 10 k ⁇
- the variable resistor R is If the resistance value Rf of f1 is 100 k ⁇ , the positive threshold voltage Vp is 2.75 V, the negative threshold voltage Vn is 2.25 V, and the hysteresis voltage Vht is 0. 5 V.
- the hysteresis comparators 14 1 and 14 2 apply the same conversion processing to the input voltage as the Schmitt-trigger type buffer elements 1 1 1 and 1 1 2 do to the input voltage. Done.
- the input power When the voltage increases and becomes larger than the positive threshold voltage Vp, the output signal is switched from the “Lo” signal to the “Hi” signal, while the input voltage decreases while the negative threshold voltage Vn If it becomes smaller, the output signal is switched from the “Hi” signal to the “Lo” signal.
- the periodic signal A input to the terminal T 1 passes through the CR delay circuit composed of the capacitance element C 1 and the resistance element R 1 and reaches the node XI 1.
- a predetermined delay has occurred in the periodic signal at the node XI1, as shown in FIG.
- the periodic signal B input to the terminal T12 passes through the CR delay circuit composed of the capacitance element C2 and the resistance element R2, and reaches the node XI2.
- the periodic signal at the node 12 has a predetermined delay. Therefore, as in FIG.
- the EX-OR element 131 has a rectangular wave converted by passing the periodic signals at the nodes X 11 and X 12 through the hysteresis comparators 141 and 142. A signal is input, an exclusive OR operation is performed between these signals, and the result is output to the terminal T11. At this time, the signal output to the terminal 11 is a rectangular wave signal having a predetermined duty ratio.
- a hysteresis comparator can be used instead of using the Schmitt trigger type buffer element.
- the positive threshold voltage Vp and the negative threshold voltage Vn are changed by changing the resistance values of the variable resistors (R f1 and R f 2 in FIG. 21).
- the hysteresis voltage Vht which is the potential difference between the two, can be arbitrarily changed. Therefore, the sensitivity characteristics of the capacitance sensor It can be easily adjusted by the configuration of the signal processing circuit.
- FIG. 22 is a circuit diagram showing a signal processing circuit for an X-axis direction component of a capacitance type sensor according to a seventh modification.
- the difference between the signal processing circuit in Fig. 22 and the signal processing circuit of the sensor of Fig. 1 is that the displacement electrode 40, which is one electrode of the capacitive elements Cl and C2, is a capacitive element. This point is directly grounded without passing through C0. Since the other configuration is the same as that of the capacitance type sensor of FIG. 1, the same reference numerals are given and the description is omitted.
- the displacement electrode 40 is grounded by a separately provided wiring, there is no need to form the reference electrode E 0 on the substrate 20. Therefore, it is possible to easily provide the wiring of the capacitor electrode on the substrate 20.
- a Schmitt-trigger-type logic element a Schmitt-trigger-type buffer element, a Schmitt-trigger-type inverter element or a hysteresis comparator is used as the signal processing circuit of the capacitance type sensor.
- a signal processing circuit having a hysteresis characteristic is used, the present invention is not limited to this. Any configuration may be used as long as the signal processing circuit has a hysteresis characteristic similar to that of the present embodiment. .
- the displacement value of the displacement electrode with respect to the fixed capacitance element electrode changes the capacitance value of the capacitance element formed between the capacitance element electrode and the displacement electrode.
- the capacitance value of the capacitance element formed between the capacitance element electrode and the conductive member changes. Any configuration may be used to change the capacitance value of the capacitive element, such as a configuration that changes the capacitance value.
- the electrodes for the capacitive element corresponding to the three directions of the X-axis direction, the Y-axis direction, and the Z-axis direction are formed.
- a capacitor element electrode may be formed as described above.
- the capacitance type sensor of the present invention is most suitable for being used as an input device for a personal computer, a mobile phone, a game, etc., a haptic sensor, an acceleration sensor or a pressure sensor.
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- General Engineering & Computer Science (AREA)
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Abstract
Description
Claims
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PCT/JP2003/000025 WO2004061400A1 (ja) | 2003-01-06 | 2003-01-06 | 静電容量式センサ |
CNB038257629A CN100465598C (zh) | 2003-01-06 | 2003-01-06 | 静电电容式传感器 |
US10/541,424 US7119552B2 (en) | 2003-01-06 | 2003-01-06 | Capacitance type force sensors |
EP03701013A EP1589327A4 (en) | 2003-01-06 | 2003-01-06 | CAPACITIVE SENSOR |
AU2003202477A AU2003202477A1 (en) | 2003-01-06 | 2003-01-06 | Capacitive sensor |
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CA2700469C (en) * | 2007-10-11 | 2016-11-15 | Cube Investments Limited | Capacitive probes and sensors, and applications therefor, and multimode wireless devices |
US8816967B2 (en) * | 2008-09-25 | 2014-08-26 | Apple Inc. | Capacitive sensor having electrodes arranged on the substrate and the flex circuit |
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- 2003-01-06 CN CNB038257629A patent/CN100465598C/zh not_active Expired - Fee Related
- 2003-01-06 US US10/541,424 patent/US7119552B2/en not_active Expired - Fee Related
- 2003-01-06 EP EP03701013A patent/EP1589327A4/en not_active Withdrawn
- 2003-01-06 AU AU2003202477A patent/AU2003202477A1/en not_active Abandoned
- 2003-01-06 WO PCT/JP2003/000025 patent/WO2004061400A1/ja active Application Filing
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Also Published As
Publication number | Publication date |
---|---|
CN100465598C (zh) | 2009-03-04 |
US20060049836A1 (en) | 2006-03-09 |
EP1589327A4 (en) | 2011-03-30 |
EP1589327A1 (en) | 2005-10-26 |
CN1720431A (zh) | 2006-01-11 |
US7119552B2 (en) | 2006-10-10 |
AU2003202477A1 (en) | 2004-07-29 |
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