JP2011145199A - Capacitance type acceleration detector and method of testing operation of capacitance type acceleration detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve precision of an operation test by increasing Coulomb force that can be generated by simply adding an antiphase oscillation circuit. <P>SOLUTION: A displacement of a heavy weight 11 is detected as a capacitance change between the heavy weight 11 and detection electrodes 12, 13. For detecting capacitance, a rectangular wave (or sinusoidal wave) voltage is applied on the heavy weight 11. Voltage Vd in an opposite phase to that of an excitation signal for detection is applied on the heavy weight 11 and the drive electrode 12. Thus, in comparison with a conventional device for applying a DC voltage on a test electrode, large Coulomb force can be generated between the heavy weight 11 and the electrode 12, thus performing a precise operation test. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a capacitive acceleration detection device and an operation test method for a capacitive acceleration detection sensor, and more specifically, has a function of performing an operation test of a capacitive acceleration detection sensor using Coulomb force. The present invention also relates to an operation test method for a capacitive acceleration detection device and a capacitive acceleration detection sensor.

  In general, a device for detecting a physical quantity using a change in the distance between electrodes and an operation test method thereof are well known. For example, a detection device having a simple structure in which two substrates are arranged to face each other and electrodes are formed on the respective substrates is known. In this detection device, one substrate is displaced based on a physical quantity such as acceleration, the distance between the electrodes formed on both substrates is changed by this displacement, and this is detected as a change in capacitance between both electrodes. ing. In addition, this detection device can be used as an acceleration detection device that detects the applied acceleration if a weight body is bonded to one substrate and the substrate is displaced based on the acceleration applied to the weight body. Is.

  Usually, when a detection device of some physical quantity is commercialized, it is necessary to perform an operation test as to whether or not this detection device outputs a correct detection signal. Conventionally, in such an operation test, a method has been adopted in which a physical quantity to be detected is actually applied to the detection device and a detection signal at that time is examined. For example, in the case of an acceleration detection device, whether or not an acceleration of a predetermined magnitude is actually applied to the detection device from a predetermined direction, and the detection signal at that time is correct according to the applied acceleration. Determine. However, in order to perform such an operation test, a dedicated test facility is required, and the test work is complicated and time-consuming. In particular, the quantity that can be tested with a dedicated test facility is limited, leading to a decrease in productivity. Therefore, such a conventional test method has a problem that it is not suitable as an operation test for a mass-produced apparatus.

  Thus, for example, an acceleration sensor inspection device and an operation test method thereof have been proposed as disclosed in Patent Document 1. In this patent document 1, a displacement electrode supported so as to be able to be displaced by the action of an external force, a fixed electrode fixed to an apparatus housing at a position facing the displacement electrode, and a distance between these two electrodes An acceleration detecting device operation test method for detecting an acceleration corresponding to an external force as an electrical signal, wherein a predetermined voltage is applied between both electrodes, and the applied voltage In the state where the displacement electrode is displaced by the Coulomb force generated based on the electric signal, an electric signal having a temporal variation component having a predetermined magnitude is given to one electrode of both electrodes, and transmitted to the other electrode at this time By comparing the magnitude of the fluctuation component to be applied with the applied voltage, the operation of this detection device is tested, and the acceleration detection device that detects the acceleration using the change in the distance between the electrodes is used. It is a work test method.

  In addition, a device for detecting a physical quantity using other changes in the distance between electrodes and its operation test method, that is, applying a voltage to the test electrode and displacing it by Coulomb force, the magnitude of the applied voltage and the amount of displacement (capacity change) For example, Patent Documents 2 and 3 have been proposed for performing an operation test by comparing (1) and (2).

JP 2002-221463 A International Publication WO1992 / 17759 Pamphlet JP 2000-146729 A

  However, normally, the magnitude of the Coulomb force that can be generated by applying a voltage to the electrode is insufficient to perform an operation test, and in order to improve the test accuracy, a highly accurate detection circuit or a high voltage is generated. Therefore, a booster circuit is required, which is an increase factor in cost.

  The present invention has been made in view of such a problem, and an object of the present invention is to increase the coulomb force that can be generated by a simple additional circuit to improve the accuracy of an operation test. An object of the present invention is to provide an operation test method for an acceleration detection device and a capacitive acceleration detection sensor.

  The present invention has been made to achieve such an object, and the invention according to claim 1 includes a displaceable weight body and an electrode disposed opposite to the weight body. A capacitance-type acceleration detection apparatus having a capacitance-type acceleration sensor configured to detect a change in capacitance between the weight body and the electrode, and an oscillation circuit for applying a voltage to the weight body; In order to perform an operation test of the capacitive acceleration sensor, an anti-phase oscillation circuit that applies an output voltage having a phase opposite to that of the output voltage of the oscillation circuit to the electrode is provided. (Corresponding to Fig. 2 and Fig. 4)

According to a second aspect of the present invention, in the first aspect of the invention, the maximum value (V _dH ) of the output voltage of the antiphase oscillator circuit is the maximum value (V _EH ) of the output voltage of the oscillator circuit. of it twice (2V _EH) the minimum value of the output voltage less than twice the (V _EL) (2V _EL) or more and the minimum value of the voltage applied to the electrode of the opposite phase oscillation circuit (V _dL) is A voltage (2V _EH −V _dH ) obtained by subtracting the maximum value (V _dH ) of the output voltage of the antiphase oscillator circuit from twice (2V _EH ) the maximum value (V _EH ) of the output voltage of the oscillation circuit. It is characterized by being. (Corresponding to Fig. 5)

  According to a third aspect of the present invention, in the second aspect of the present invention, the minimum value of the output voltage of the antiphase oscillation circuit is equal to the ground potential. (Corresponding to Fig. 6)

  The invention according to claim 4 is the invention according to claim 3, wherein the minimum value of the output voltage of the oscillation circuit is equal to the ground potential. (Corresponding to FIG. 7)

  The invention described in claim 5 is the invention described in claim 4, characterized in that the maximum value of the output voltage of the antiphase oscillator circuit is equal to the maximum value of the output voltage of the oscillator circuit. (Corresponding to FIG. 8)

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the capacitive acceleration sensor faces one detection electrode and the one detection electrode. It has the other detection electrode provided, and the displaceable weight body provided so that all or a part of said one and the other detection electrode may be inserted | pinched.

  According to a seventh aspect of the present invention, there is provided the CV conversion circuit according to any one of the first to sixth aspects, wherein a change in charge generated on the one detection electrode by the oscillation circuit is converted into a voltage; And a demodulation circuit that demodulates the output of the CV conversion circuit into a DC component.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the capacitive acceleration sensor is coupled to a displaceable weight body and the weight body. A pair of comb-shaped movable electrodes; a pair of one fixed electrode and a pair of other fixed electrodes arranged opposite to each other with the comb-shaped movable electrode interposed therebetween; and a beam member coupled to both ends of the weight body; One fixed anchor coupled to the beam member, the other fixed anchor coupled to the beam member, and a substrate supporting the one and other fixed anchors, the comb movable electrode and the one A capacitance change between the fixed electrode and a capacitance change between the comb movable electrode and the other fixed electrode is detected. (Corresponding to FIG. 11)

  The invention according to claim 9 is the invention according to claim 8, wherein a plurality of sets of the pair of comb movable electrodes are provided.

  The invention according to claim 10 is provided with a displaceable weight body and an electrode disposed opposite to the weight body, and the capacitance between the weight body and the electrode is changed. In an operation test method for a capacitive acceleration sensor to be detected, an oscillation step of applying a voltage to the weight body, and an output from the oscillation step for performing an operation test of the capacitive acceleration sensor And an anti-phase oscillation step applied to the electrode with an output voltage having an anti-phase with respect to the voltage.

According to an eleventh aspect of the present invention, in the invention according to the tenth aspect, the maximum value (V _dH ) of the output voltage by the anti-phase oscillation step is the maximum value (V _EH ) of the output voltage by the oscillation step. twice and the (2V _EH) the minimum value of the output voltage less than twice the (V _EL) (2V _EL) or more and the minimum value of the voltage applied to the electrode by the reverse phase oscillation step (V _dL) is A voltage (2V _EH −V _dH ) obtained by subtracting the maximum value (V _dH ) of the output voltage due to the anti-phase oscillation step from twice (2V _EH ) the maximum value (V _EH ) of the output voltage due to the oscillation step. It is characterized by being.

  According to a twelfth aspect of the invention, in the invention of the eleventh aspect, a minimum value of the output voltage by the antiphase oscillation step is equal to a ground potential.

  According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention, the minimum value of the output voltage by the oscillation step is equal to the ground potential.

  The invention described in claim 14 is characterized in that, in the invention described in claim 13, the maximum value of the output voltage by the anti-phase oscillation step is equal to the maximum value of the output voltage by the oscillation step.

  The invention according to claim 15 is the invention according to any one of claims 10 to 14, wherein a CV conversion step of converting a change in charge generated on the one detection electrode by the oscillation step into a voltage; A demodulation step of demodulating the output of the CV conversion step into a DC component.

  According to the present invention, a voltage having a phase opposite to that applied to the weight body is applied to the test electrode, thereby generating a large Coulomb force between the weight body and the electrode as compared with applying a DC voltage to the test electrode. Can be made. As a result, it is possible to achieve an effect that it is possible to realize an operation test method for a capacitance type acceleration detection device and a capacitance type acceleration detection sensor that can perform an operation test with higher accuracy than conventional ones.

It is comparison explanatory drawing for demonstrating the operation | movement test method of the capacitance-type acceleration sensor used for a capacitance-type acceleration detection apparatus. It is principle explanatory drawing for demonstrating the operation | movement test method of the capacitive acceleration sensor used for the capacitive acceleration detection apparatus which concerns on this invention. It is a comparison circuit diagram for demonstrating the capacitance-type acceleration detection apparatus provided with the operation test function of a capacitance-type acceleration sensor. It is a circuit diagram for demonstrating the capacitance-type acceleration detection apparatus which concerns on this invention provided with the operation test function of a capacitance-type acceleration sensor. It is a figure which shows the graph for demonstrating an example of the relationship between the output voltage of the oscillation circuit with which the electrostatic capacitance type acceleration detection apparatus which concerns on this invention is equipped, and the output voltage of an antiphase oscillation circuit. It is a figure which shows the graph for demonstrating the other example of the relationship between the output voltage of the oscillation circuit with which the electrostatic capacitance type acceleration detection apparatus which concerns on this invention is equipped, and the output voltage of an antiphase oscillation circuit. It is a figure which shows the graph for demonstrating the further another example of the relationship between the output voltage of the oscillation circuit with which the electrostatic capacitance type acceleration detection apparatus which concerns on this invention is equipped, and the output voltage of an antiphase oscillation circuit. It is a figure which shows the graph for demonstrating the further another example of the relationship between the output voltage of the oscillation circuit with which the electrostatic capacitance type acceleration detection apparatus which concerns on this invention is equipped, and the output voltage of an antiphase oscillation circuit. It is a figure which shows the flowchart for demonstrating the operation | movement test method of the capacitive acceleration sensor which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram for demonstrating Example 1 of the capacitive acceleration sensor in the capacitive acceleration detection apparatus which concerns on this invention, (a) is a top view, (b) is AA 'of (a). It is line sectional drawing. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram for demonstrating Example 2 of the capacitive acceleration sensor in the capacitive acceleration detection apparatus based on this invention, (a) is a top view, (b) is AA 'of (a). Line sectional drawing, (c) is a BB 'line sectional view of (a).

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a comparative explanatory diagram for explaining an operation test method of a capacitive acceleration sensor used in the capacitive acceleration detecting device, and FIG. 2 is a schematic diagram of the capacitive acceleration detecting device according to the present invention. It is principle explanatory drawing for demonstrating the operation | movement test method of the capacitance-type acceleration sensor used.

  First, based on FIG. 2, by applying a voltage having a phase opposite to that of the excitation signal for detection between the weight body and the electrode, a larger Coulomb force than when a DC voltage as shown in FIG. 1 is applied. The fact that the operation test accuracy can be improved will be described. Before that, the Coulomb force generated when a DC voltage is applied to the weight body will be described with reference to FIG.

  The capacitive acceleration sensor 10 shown in FIG. 1 detects the displacement of the weight body 11 as a capacitance change between the weight body 11 and the detection electrodes 12 and 13. For this capacitance detection, a rectangular wave (or sine wave) voltage is applied to the weight body 11. At this time, the Coulomb force that can be generated by applying the DC voltage Vd by the DC voltage generating circuit 22 between the weight body 11 and the drive electrode 12 is expressed by the following Equation 1.

  This indicates the maximum Coulomb force when the maximum voltage applied to the weight body 11 and the drive electrode 12 is Vd. A capacitance change between the weight body 11 and the detection electrode 13 caused by the Coulomb force is taken out as an output voltage by the CV converter 21.

  In the present invention, in the capacitive acceleration sensor 10 shown in FIG. 2, a voltage Vd having a phase opposite to that of the excitation signal for detection is applied between the weight body 11 and the drive electrode 12. The output in this case is as shown in Equation 2 below.

  This indicates the maximum Coulomb force when the maximum voltage applied to the weight body 11 and the drive electrode 12 is Vd. A capacitance change between the weight body 11 and the detection electrode 13 caused by the Coulomb force is taken out as an output voltage by the CV converter 21.

Comparing Formula 1 and Formula 2 described above, it can be seen that the Coulomb force generated in the capacitive acceleration sensor of the present invention is larger. In this case, the relationship between the output voltage of the oscillation circuit applied to the drive electrode 12 and the output voltage of the antiphase oscillation circuit has a relationship shown in FIG. That is, the minimum value V _dL of the output voltage of the anti-phase oscillation circuit is equal to the ground potential, the minimum value V _EL of the output voltage of the oscillation circuit is equal to the ground potential, and the maximum value V _dH of the anti-phase oscillation circuit is the oscillation circuit _Is equal to the maximum value _VEH .

  Next, based on a comparison circuit diagram corresponding to the comparative explanatory diagram shown in FIG. 1, a capacitive acceleration detection device having an operation test function of the capacitive acceleration sensor will be described.

  FIG. 3 is a comparison circuit diagram for explaining a capacitive acceleration detecting device having an operation test function of the capacitive acceleration sensor. This capacitance type acceleration detection device includes a displaceable weight body 11 and electrodes 12 and 13 disposed opposite to the weight body 11, and the weight body 11 is interposed between the electrodes 12 and 13. It has a capacitance type acceleration sensor 10 adapted to detect a change in capacitance.

  Also, a CV converter 21 that detects the capacitance between the one detection electrode 13, a demodulation circuit 23 that converts the output of the CV converter 21 into direct current, an oscillation circuit 24 that applies a voltage to the weight body 11, It is composed of a DC voltage generating circuit 22 for applying a voltage to the other detection electrode 12.

  The CV conversion circuit 21 includes an operational amplifier 21a having a non-inverting input terminal connected to the detection electrode of the capacitive element of the capacitive acceleration sensor 10, and a resistor connected in parallel between the non-inverting input terminal and the output terminal. R and a capacitive element C are provided. Further, Vcom is applied to the inverting input terminal of the operational amplifier 21a.

  The oscillation circuit 24 applies a high frequency voltage to the weight body 11 of the capacitive acceleration sensor 10. The capacitive acceleration sensor 10 has a configuration as shown in FIGS. 10 and 11 to be described later. The CV conversion circuit 21 converts a capacitance change into a detection voltage based on an output signal from the capacitive acceleration sensor 10 and outputs an acceleration signal. The demodulating circuit 23 demodulates the acceleration signal modulated to a high frequency into a DC component. Based on the output from the demodulation circuit 23, the X, Y, and Z axis offsets are adjusted, and acceleration components Ax, Ay, and Az are output, respectively.

  FIG. 4 is a circuit diagram for explaining a capacitive acceleration detecting device according to the present invention having an operation test function of a capacitive acceleration sensor, and corresponds to the above-described principle explanatory diagram of the present invention. . The difference between the circuit diagram shown in FIG. 4 and the comparison circuit diagram of FIG. 3 described above is that an antiphase oscillation circuit 25 is provided on the other detection electrode (test electrode) 12 in FIG.

  That is, the capacitance type acceleration detection device of the present invention includes a displaceable weight body 11 and electrodes 12 and 13 disposed to face the weight body 11, and the weight body 11 and the electrode 12. , 13 is provided with a capacitance-type acceleration sensor 10 that detects a change in capacitance between them. Further, in order to perform an operation test of the oscillation circuit 24 for applying a voltage to the weight body 11 and the capacitive acceleration sensor 10, an output voltage having an opposite phase to the output voltage of the oscillation circuit 24 is applied to the electrode 12. The anti-phase oscillation circuit 25 is provided.

  The capacitive acceleration sensor 10 includes one detection electrode 13, the other detection electrode 12 provided to face the one detection electrode 13, and the entire one and other detection electrodes 12 and 13. Or it has the displaceable weight body 11 provided so that one part may be pinched | interposed. A specific configuration of the capacitive acceleration sensor 10 will be described later with reference to FIGS. 9 and 10.

  Similarly to FIG. 3, a CV conversion circuit 21 that converts a charge change generated on one detection electrode 13 by the oscillation circuit 24 into a voltage, and a demodulation circuit 23 that demodulates the output of the CV conversion circuit 21 into a DC component, It has.

Further, the phase of the output voltage of the anti-phase oscillation circuit 25 differs from the phase of the output voltage of the oscillation circuit 24 by 180 °. Further, when the maximum value of the output voltage of the oscillation circuit 24 is V _EH and the minimum value is V _EL , the maximum value V _dH and the minimum value V _dL of the voltage output from the antiphase oscillation circuit 25 are expressed by the following equation (3). Shall be satisfied.

FIG. 5 is a graph for explaining an example of the relationship between the output voltage of the oscillation circuit and the output voltage of the antiphase oscillation circuit included in the capacitive acceleration detection device according to the present invention. In this case, if the distance between the weight body 11 and the detection electrode 12 is d and the sum of the areas of the detection electrode 12 is S, the Coulomb force F _c1 generated between the weight body 11 and the detection electrode 2 is The following formula 5 is satisfied.

In FIG. 3, the Coulomb force F _c2 generated when the value output from the DC voltage generation circuit 22 is constant at V _dH is expressed by Equation 6 below.

In FIG. 3, the Coulomb force F _c3 generated when the value output from the DC voltage generation circuit 22 is constant at V _dL is expressed by the following Equation 7.

When Equation 3 and Equation 4 described above hold, the size of F _c1 is equal to or greater than the sizes of F _c2 and F _c3 . Thereby, compared with applying a DC voltage to an electrode, a big Coulomb force can be generated between the weight body 11 and the electrode 12. Therefore, the capacitance type acceleration detection device capable of increasing the capacitance change generated between the weight body 11 and the electrode 13 caused by the Coulomb force and performing a high-precision operation test at a lower cost than the conventional one. Can be realized.

That is, the maximum value V _dH of the output voltage of the anti-phase oscillation circuit 25 is 2V _EH or less which is twice the maximum value V _EH of the oscillation circuit 24 and 2V _{EL which is} twice the minimum value V _EL of the output voltage. And the minimum value V _{dL of the} voltage applied to the electrode of the anti-phase oscillation circuit 25 is 2V _{EH which is} twice the maximum value V _EH of the output voltage of the oscillation circuit 24, and the maximum output voltage of the anti-phase oscillation circuit 25 It is preferable that the voltage 2V _EH −V _dH is a value obtained by subtracting the value V _dH .

FIG. 6 is a graph showing another example of the relationship between the output voltage of the oscillation circuit and the output voltage of the antiphase oscillation circuit included in the capacitive acceleration detection device according to the present invention. This is the case where the minimum value V _dL of the output voltage of the circuit 25 is equal to the ground potential.

FIG. 7 is a diagram showing a graph for explaining still another example of the relationship between the output voltage of the oscillation circuit and the output voltage of the antiphase oscillation circuit included in the capacitive acceleration detection device according to the present invention. This is the case where the minimum value V _dL of the output voltage of the oscillation circuit 25 is equal to the ground potential and the minimum value V _EL of the output voltage of the oscillation circuit 24 is equal to the ground potential.

FIG. 8 is a diagram illustrating a graph for explaining still another example of the relationship between the output voltage of the oscillation circuit and the output voltage of the antiphase oscillation circuit included in the capacitive acceleration detection device according to the present invention. The minimum value V _dL of the output voltage of the oscillation circuit 25 is equal to the ground potential, the minimum value V _EL of the output voltage of the oscillation circuit 24 is equal to the ground potential, and the maximum value V _dH of the antiphase oscillation circuit 25 is This is the case where the maximum value V _{EH of} 24 is equal. This case corresponds to the case of FIG. 2 described above.

  5 to 8, description is made using a rectangular wave having a duty ratio of 50%, but a rectangular wave having an arbitrary duty ratio may be used. A sine wave may be used instead of the rectangular wave.

  FIG. 9 is a flowchart for explaining the operation test method for the capacitive acceleration sensor according to the present invention. This operation test method includes a displaceable weight body 11 and electrodes 12 and 13 disposed so as to face the weight body 11, and the capacitance between the weight body 11 and the electrodes 12 and 13. This is an operation test method for the capacitive acceleration sensor 10 that detects a change.

  First, a voltage is applied to the weight body 11 by the oscillation step (S1). Next, in an antiphase oscillation step (S2), an output voltage having an antiphase with respect to the output voltage of the oscillation step (S1) is applied to the test electrode 12.

The maximum value V _dH of the output voltage by this antiphase oscillation step (S2) is 2V _EH or less which is twice the maximum value V _EH of the output voltage by the oscillation step (S1) and twice the minimum value V _EL of the output voltage. The minimum value V _{dL of the} voltage applied to the test electrode 12 in the anti-phase oscillation step (S2) is 2V _EL or more and reverse from 2V _{EH which is} twice the maximum value V _EH of the output voltage in the oscillation step (S1). The voltage 2V _EH −V _dH is a value obtained by subtracting the maximum value V _dH of the output voltage in the phase oscillation step (S2).

  Next, in the CV conversion step (S3), the change in charge generated on one detection electrode due to the oscillation step (S1) is converted into a voltage. Next, in the demodulation step (S4), the output of the CV conversion step (S3) is demodulated into a DC component.

  By such an operation test method, the capacitance change generated between the weight body 11 and the electrode 13 caused by the Coulomb force can be increased, and an electrostatic test capable of performing a high-accuracy operation test at a lower cost than the conventional one. A capacitive acceleration detection device can be realized.

  10A and 10B are configuration diagrams for explaining the capacitive acceleration sensor according to the present invention. FIG. 10A is a top view, and FIG. 10B is FIG. It is AA 'line sectional drawing of.

  The capacitive acceleration sensor 30 has a frame body 34 holding a displaceable weight body 31a to 31e (corresponding to the weight body 11 in FIG. 4) and the weight bodies 31a to 31e. Detection electrodes 35a to 35d (35c and 35d are not shown; corresponding to the detection electrodes 12 in FIG. 4) provided on the first substrate 37, and include weights 31a to 31e and detection electrodes 35a to 35d. It is comprised so that the change of the electrostatic capacitance between may be detected.

  The weight bodies 31a to 31e are held by beam members 33a to 33d, and the ends of the respective beam members are held by column members (pillars) 32a to 32d.

  The beam member 33a is sandwiched between the weight body 31a and the weight body 31b, the beam member 33b is sandwiched between the weight body 31b and the weight body 31c, and the beam member 33c is sandwiched between the weight body 31c and the weight body 31c. The beam member 33d is sandwiched between the weight body 31d and the weight body 31a.

  Further, the weight bodies 31a and 31e have a center portion 31e arranged at the intersection of the beam members 33a and 33d, and are arranged in a rice field from the center portion 31e along the frame body 34 and the beam members 33a and 33d. It has peripheral portions 31a and 31d. The shape of the detection electrodes 35a to 35d is a quadrangle similar to the weight bodies 31a to 31d.

  Similarly, it includes detection electrodes 36a to 36d (36c and 36d are not shown; corresponding to the detection electrode 13 in FIG. 4) provided on the second substrate 38, and the weights 31a to 31e and the detection electrodes are provided. It is configured to detect a change in capacitance between 36a and 36d.

  FIGS. 11A to 11C are configuration diagrams for explaining a capacitive acceleration sensor according to the present invention. FIG. 11A is a top view, and FIG. 11B is FIG. FIG. 11C is a cross-sectional view taken along line AA ′ of FIG. 11A, and FIG. 11C is a cross-sectional view taken along line BB ′ of FIG.

  The capacitive acceleration sensor 40 is configured such that a displaceable weight body 46, comb-shaped movable electrodes 47a to 47f coupled to the weight body 46, and the comb-shaped movable electrodes 47a to 47f are opposed to each other. The fixed electrodes 43a to 43f and the fixed electrodes 44a to 44f, the beam members 42a to 42d coupled to the weight body 46, the fixed anchor 41a coupled to the beam members 42a and 42c, the beam members 42b and 42d, The fixed anchor 41b which couple | bonded and the board | substrate 45 which supports these fixed anchors 41a and 41b are provided, The electrostatic capacitance change between the comb movable electrodes 47a and 47f and the fixed electrodes 43a and 43f, and the comb movable electrode The capacitance change between 47a to 47f and the fixed electrode 44a to 44f is detected.

  It is obvious that a capacitive acceleration detecting device having an operation test function as shown in FIG. 4 can be configured for such a capacitive acceleration sensor 40 as well. Further, by the same operation test method, it is possible to increase the capacitance change generated between the comb movable electrodes 47a to 47f and the fixed electrodes 43a to 43f or the fixed electrodes 44a to 44f of the weight body 46 caused by the Coulomb force. It is also clear that a capacitive acceleration detection device capable of performing a high-precision operation test at a lower cost than the conventional one can be realized.

DESCRIPTION OF SYMBOLS 10 Capacitance type acceleration sensor 11 Weight body 12, 13 Detection electrode 21 CV converter 22 DC voltage generation circuit 23 Demodulation circuit 24 Oscillation circuit 25 Antiphase oscillation circuit 30, 40 Capacitance type acceleration sensor 31a to 31e, 46 Weight body 32a and 32d Strut member (pillar)
33a to 33d Beam member 34 Frame 35a to 35d, 36a to 36d Detection electrode 37 First substrate 38 Second substrate 40 Capacitive acceleration sensors 41a, 41b Fixed anchor 42a to 42d Beam member 43a to 43f, 44a to 44f Fixed Electrode 45 Substrate 47a and 47f Comb movable electrode

Claims (15)

A capacitive acceleration sensor comprising a displaceable weight body and an electrode disposed opposite to the weight body, and detecting a change in capacitance between the weight body and the electrode. In a capacitive acceleration detecting device having
An oscillation circuit for applying a voltage to the weight body;
An anti-phase oscillation circuit that applies an output voltage having a phase opposite to that of the output voltage of the oscillation circuit to the electrode in order to perform an operation test of the capacitive acceleration sensor; Capacitive acceleration detector. 2 the maximum value of the output voltage of the opposite phase oscillation circuit (V _dH) is twice (2V _EH) the minimum value of the output voltage is equal to or less than a maximum value of the output voltage of said oscillator circuit (V _EH) of (V _EL) times and the (2V _EL) or more and the minimum value of the voltage applied to the electrode of the opposite phase oscillation circuit (V _dL) is twice (2V _EH maximum value of the output voltage of said oscillator circuit (V _EH) 2. A capacitance-type acceleration detecting device according to claim 1, wherein a voltage (2V _EH −V _dH ) is obtained by subtracting a maximum value (V _dH ) of the output voltage of the antiphase oscillation circuit from .   3. The capacitive acceleration detection device according to claim 2, wherein a minimum value of the output voltage of the antiphase oscillation circuit is equal to a ground potential.   4. The capacitive acceleration detecting device according to claim 3, wherein a minimum value of the output voltage of the oscillation circuit is equal to a ground potential.   5. The capacitive acceleration detection device according to claim 4, wherein the maximum value of the output voltage of the antiphase oscillator circuit is equal to the maximum value of the output voltage of the oscillator circuit.   The capacitive acceleration sensor includes one detection electrode, the other detection electrode provided to face the one detection electrode, and the whole or a part of the one and the other detection electrodes. A capacitive acceleration detecting device according to any one of claims 1 to 5, further comprising a displaceable weight body.   2. A CV conversion circuit for converting a charge change generated on the one detection electrode by the oscillation circuit into a voltage, and a demodulation circuit for demodulating an output of the CV conversion circuit into a DC component. The electrostatic capacitance type acceleration detection apparatus in any one of thru | or 6. The capacitive acceleration sensor is
A displaceable weight body;
A pair of comb-shaped movable electrodes coupled to the weight body;
A pair of one fixed electrode and a pair of the other fixed electrode disposed opposite to each other across the comb movable electrode;
A beam member coupled to both ends of the weight body;
One fixed anchor coupled to the beam member and the other fixed anchor coupled to the beam member;
A substrate for supporting the one and the other fixed anchors,
A capacitance change between the comb movable electrode and the one fixed electrode and a capacitance change between the comb movable electrode and the other fixed electrode are detected. Item 8. The capacitive acceleration detection device according to any one of Items 1 to 7.   The capacitive acceleration detecting device according to claim 8, wherein a plurality of pairs of comb-shaped movable electrodes are provided. A capacitive acceleration sensor comprising a displaceable weight body and an electrode disposed opposite to the weight body, and detecting a change in capacitance between the weight body and the electrode. In the operation test method of
An oscillation step of applying a voltage to the weight body;
An anti-phase oscillation step of applying to the electrode with an output voltage having a phase opposite to that of the output voltage of the oscillation step in order to perform an operation test of the capacitance-type acceleration sensor; Test method of a type acceleration sensor. 2 the maximum value of the output voltage due to the opposite phase oscillation step (V _dH) is twice (2V _EH) the minimum value of the output voltage is equal to or less than a maximum value of the output voltage by the oscillation step (V _EH) of (V _EL) times and the (2V _EL) or more and 2 times the minimum value of the voltage applied to the electrode by the reverse phase oscillation step (V _dL) is the maximum value of the output voltage by the oscillation step (V _EH) (2V _EH 11. A capacitance-type acceleration sensor according to claim 10, which is a voltage (2V _EH −V _dH ) obtained by subtracting the maximum value (V _dH ) of the output voltage generated by the antiphase oscillation step from Operation test method.   12. The operation test method for a capacitive acceleration sensor according to claim 11, wherein the minimum value of the output voltage in the antiphase oscillation step is equal to a ground potential.   13. The operation test method for a capacitive acceleration sensor according to claim 12, wherein the minimum value of the output voltage in the oscillation step is equal to a ground potential.   The method of testing an operation of a capacitive acceleration sensor according to claim 13, wherein the maximum value of the output voltage due to the reverse phase oscillation step is equal to the maximum value of the output voltage due to the oscillation step.   11. The method according to claim 10, further comprising: a CV conversion step for converting a charge change generated on the one detection electrode due to the oscillation step into a voltage; and a demodulation step for demodulating an output of the CV conversion step into a DC component. 14. An operation test method for a capacitive acceleration sensor according to any one of claims 14 to 14.

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