Physical quantity sensor, electronic device, and moving body

Abstract

The present application provides a physical quantity sensor, an electronic device, and a moving body, which detect a state until the physical quantity sensor fails. A sensor failure prediction system predicts a failure of a physical quantity sensor including a vibration element sheet that is driven to vibrate in accordance with a drive signal and outputs a detection signal based on a physical quantity, the sensor failure prediction system having: a memory that stores reference information related to a reference value of the drive signal or the detection signal; and a processor that outputs prediction information related to a state of periodicity or continuity until the physical quantity sensor fails, based on signal information related to a measured value of the drive signal or the detection signal and the reference information.

Description

[0001] This application is a divisional application of the invention patent application entitled "Sensor Fault Prediction System, Sensor Fault Prediction Method, Physical Quantity Sensor, Electronic Device and Moving Body", filed on March 20, 2020, with application number 202010199432.5. Technical Field

[0002] This invention relates to physical quantity sensors, electronic devices, and mobile bodies. Background Technology

[0003] Techniques for determining faults in physical quantity sensors such as vibration-type gyroscope sensors are known. For example, in the technology described in Patent Document 1, a fault in the angular velocity detection device is determined based on the leakage signal of the oscillator in the angular velocity detection device. More specifically, the output signal of an integral circuit that monitors the variation of the amplitude of the leakage signal is monitored. If the output signal is within a specified range, a signal indicating no abnormality is output; conversely, if the output signal is outside the specified range, a signal indicating an abnormality is output.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2000-171257

[0005] In the technology described in Patent Document 1, since only two signals, "no abnormality" and "abnormality," are output, there is a problem that the state cannot be detected in advance until the angular velocity detection device malfunctions. Summary of the Invention

[0006] One aspect of the present invention provides a sensor fault prediction system that predicts a fault in a physical quantity sensor comprising a vibrating element plate that is driven to vibrate according to a drive signal and outputs a detection signal based on a physical quantity. The sensor fault prediction system includes: a memory storing reference information related to a reference value of the drive signal or the detection signal; and a processor that outputs prediction information related to a phased or continuous state up to the point where the physical quantity sensor fails, based on signal information related to the measured value of the drive signal or the detection signal and the reference information.

[0007] One aspect of the present invention provides a sensor fault prediction method as follows: obtaining signal information related to the measured value of a drive signal or a detection signal from a physical quantity sensor comprising a vibrating element plate, the vibrating element plate being driven to vibrate according to the drive signal, outputting the detection signal based on the physical quantity, and outputting prediction information related to the phased or continuous state until the physical quantity sensor fails, based on the signal information and reference information related to the reference value of the drive signal or the detection signal.

[0008] One embodiment of the present invention provides a physical quantity sensor comprising: a vibrating element plate that is driven to vibrate according to a drive signal and outputs a detection signal based on a physical quantity; a memory that stores reference information related to a reference value of the drive signal or the detection signal; and a processor that outputs predictive information related to a phased or continuous state until the physical quantity sensor malfunctions, based on signal information related to the measured value of the drive signal or the detection signal and the reference information. Attached Figure Description

[0009] Figure 1 This is a diagram illustrating the general structure of a sensor fault prediction system according to an embodiment.

[0010] Figure 2 This is a cross-sectional view showing an example of the structure of a physical quantity sensor according to an embodiment.

[0011] Figure 3 This is a block diagram illustrating the structure of the circuit elements of the physical quantity sensor in the embodiment.

[0012] Figure 4 It is a graph showing the relationship between the vacuum level inside the package of a physical quantity sensor and the driving voltage.

[0013] Figure 5 This is a diagram showing an example of a decision table that represents the relationship between reference information and decision results.

[0014] Figure 6 This is another example of a decision table that shows the relationship between baseline information and decision results.

[0015] Figure 7 This is a flowchart illustrating the operation of the sensor fault prediction system according to an embodiment.

[0016] Figure 8 It is a perspective view that roughly shows the structure of a mobile or notebook-type personal computer as an example of an electronic device.

[0017] Figure 9 This is a top view that roughly shows the structure of a smartphone as an example of an electronic device.

[0018] Figure 10 This is a perspective view that roughly shows the structure of a digital camera as an example of an electronic device.

[0019] Figure 11 This is a perspective view of a car as an example of a moving object.

[0020] Label Explanation

[0021] 1: Physical quantity sensor; 10: Vibration element plate; 31: Processor; 32: Memory; 40: Package; 100: Sensor fault prediction system; 1100: Personal computer; 1200: Smartphone; 1300: Digital camera; 1440: Personal computer; 1500: Automobile; D1: Reference information; D2: Predictive information; DQ: Drive signal; IQ1: Detection signal; IQ2: Detection signal; Va: Reference value. Detailed Implementation

[0022] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Note that the dimensions or scales of the parts in the drawings may differ slightly from actual dimensions; some parts are shown schematically for ease of understanding. Furthermore, unless otherwise specified in the following description, the scope of the present invention is not limited to these embodiments.

[0023] A-1. Overview of Sensor Fault Prediction Systems

[0024] Figure 1 This is a diagram showing the schematic structure of the sensor fault prediction system 100 according to an embodiment. Figure 2 This is a cross-sectional view showing an example of the structure of the physical quantity sensor according to the embodiment. The sensor fault prediction system 100 is a system for predicting faults in the physical quantity sensor 1. The sensor fault prediction system 100 includes the physical quantity sensor 1, a processor 101, a memory 102, an input device 103, and a display device 104. They are connected to each other via a bus 105 in a manner that enables them to communicate with each other.

[0025] Physical quantity sensor 1 is a gyroscope sensor that detects angular velocity, an example of a physical quantity. Figure 1 In the example shown, the physical quantity sensor 1 is a vibration-type gyroscope sensor with a vibrating element plate 10. The vibrating element plate 10 is driven to vibrate according to a drive signal DQ, and outputs detection signals IQ1 and IQ2 based on angular velocity ω as an example of a physical quantity. A circuit element 30 is electrically connected to the vibrating element plate 10. The circuit element 30 has the functions of receiving a feedback signal DI from the vibrating element plate 10 and outputting a drive signal DQ to drive the vibrating element plate 10, detecting the detection signals IQ1 and IQ2 from the vibrating element plate 10, and outputting predictive information D2 until the physical quantity sensor 1 malfunctions. The physical quantity sensor 1 outputs a signal containing the predictive information D2 to the outside. This signal may also contain other information such as detection information related to the physical quantity detected by the physical quantity sensor 1. The output of this signal is, for example, triggered by a signal SG from an external source. Furthermore, the physical quantity sensor 1 will be described in detail later.

[0026] The processor 101 is a device that controls various parts of the sensor fault prediction system 100 and processes various data. The processor 101 may be configured to include, for example, a processor such as a CPU (Central Processing Unit). Alternatively, the processor 101 may consist of a single processor or multiple processors. Furthermore, some or all of the functions of the processor 101 may be implemented using hardware such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), or FPGA (Field Programmable Gate Array).

[0027] The memory 102 is a device for storing various programs, including the program P0 executed by the processor 101, and various data processed by the processor 101. The memory 102 may be configured, for example, to include a hard disk drive or a semiconductor memory. Alternatively, part or all of the memory 102 may be located in an external memory or server, etc., of the sensor fault prediction system 100.

[0028] Input device 103 is a device that accepts operations from the user. For example, input device 103 may be configured to include a touchpad, touch panel, or mouse, etc. Here, if input device 103 is configured to include a touch panel, it may also serve as display device 104. In addition, input device 103 can be provided as needed or omitted.

[0029] The display device 104 displays various images under the control of the processor 101. The display device 104 may be, for example, a display device comprising various display panels such as a liquid crystal display panel or an organic EL (electro-luminescence) display panel. Alternatively, the display device 104 may be omitted as needed.

[0030] In the sensor fault prediction system 100 with the above-described general structure, the processor 101 functions as a control unit 101a by reading and executing program P0. The control unit 101a performs prescribed processing based on the prediction information D2 from the physical quantity sensor 1. This prescribed processing is appropriately determined according to the type of electronic device or mobile body on which the sensor fault prediction system 100 is assembled. For example, the control unit 101a may cause the display device 104 to display an image based on the prediction information D2, or to stop the operation of the electronic device or mobile body based on the detection result of the physical quantity sensor 1 according to the prediction information D2. Specific examples of this prescribed processing will be given in the description of the electronic device and mobile body described later.

[0031] A-2. Structure of Physical Quantity Sensors

[0032] Figure 2 This is a cross-sectional view showing a structural example of the physical quantity sensor 1 according to the embodiment. Hereinafter, according to... Figure 1 and Figure 2 The structure of physical quantity sensor 1 will be described below. For ease of explanation, mutually perpendicular X-axis, Y-axis, and Z-axis will be used appropriately in the following description. Figure 1 and Figure 2 The arrows representing these axes are appropriately illustrated. The side the arrow points to is the + side, and the opposite side is the - side. Furthermore, one or both of the +X and -X directions are simply referred to as the "X direction," one or both of the +Y and -Y directions are simply referred to as the "Y direction," and one or both of the +Z and -Z directions are simply referred to as the "Z direction." Here, the Z direction is the thickness direction of the vibrating element plate 10. The view from the -Z or +Z direction is called the "top view."

[0033] Figure 1 and Figure 2 The physical quantity sensor 1 shown is a vibration-type gyroscope sensor that detects the angular velocity ω around the Z-axis. For example... Figure 2 As shown, the physical quantity sensor 1 includes a vibrating element plate 10, a support member 20, a circuit element 30, and a package 40. The vibrating element plate 10, the support member 20, and the circuit element 30 are each housed in the package 40. Here, the vibrating element plate 10 is supported on the package 40 via the support member 20. The various parts of the physical quantity sensor 1 will be briefly described below.

[0034] Figure 1 and Figure 2The vibrating element plate 10 shown is a sensor element plate made of a piezoelectric material. Examples of such piezoelectric materials include quartz, lithium tantalate, and lithium niobate. Among these, quartz is preferred as the constituent material of the vibrating element plate 10. In this case, the frequency-temperature characteristics of the vibrating element plate 10 can be improved compared to using other piezoelectric materials. The following description focuses on the case where the vibrating element plate 10 is made of quartz. The X-axis, Y-axis, and Z-axis shown in each figure correspond to the electrical axis, mechanical axis, and optical axis of the quartz crystal axis constituting the vibrating element plate 10, respectively. Furthermore, in Figure 1 and Figure 2 The electrodes disposed on the surface of the vibrating element plate 10 are omitted from the illustration.

[0035] The vibrating element plate 10 has a so-called double-T structure. Specifically, the vibrating element plate 10 has a base 11, a first detection arm 12a and a second detection arm 12b extending from the base 11 in the +Y and -Y directions, a first connecting arm 13a and a second connecting arm 13b extending from the base 11 in the +X and -X directions, a first drive arm 14a and a first drive arm 14b extending from the first connecting arm 13a in the +Y and -Y directions, and a second drive arm 15a and a second drive arm 15b extending from the second connecting arm 13b in the +Y and -Y directions. Furthermore, the shape of each part of the vibrating element plate 10 is not limited to... Figure 1 The shape shown. For example, slots or holes opening in the Z direction can also be appropriately provided on each arm of the vibrating element plate 10 along the extension direction of the arm. In addition, the width of each arm can also be constant.

[0036] Although not shown, a pair of drive electrodes are provided on the first drive arm 14a, the first drive arm 14b, the second drive arm 15a, and the second drive arm 15b, respectively, to cause these drive arms to bend and vibrate in the X direction. A drive signal DQ is input to one of the drive electrodes, and a feedback signal DI is output from the other. Additionally, although not shown, a pair of detection electrodes are provided on the first detection arm 12a and the second detection arm 12b, which detect the charge generated by the bending and vibrating of these detection arms in the X direction. A detection signal IQ1 is output from one of the detection electrodes, and a detection signal IQ2 is output from the other. Furthermore, a plurality of terminals electrically connected to the aforementioned drive electrodes and detection electrodes are provided on the base 11. The materials used to construct the drive electrodes, detection electrodes, and terminals are not particularly limited, and examples include metals such as gold (Au), chromium (Cr), and titanium (Ti).

[0037] The following is a brief explanation of the detection of the angular velocity ω using the vibrating element plate 10. First, an alternating voltage is applied between a pair of drive electrodes (not shown) via a drive signal DQ. Then, as... Figure 1 As indicated by the middle arrow A, the first drive arm 14a and the second drive arm 15a bend and vibrate in opposite directions in the X direction, and in phase with the first drive arm 14a and the second drive arm 15a, the first drive arm 14b and the second drive arm 15b bend and vibrate in opposite directions in the X direction. At this time, without applying an angular velocity to the vibrating element plate 10, since the first drive arms 14a, 14b and the second drive arms 15a, 15b vibrate symmetrically with respect to the YZ plane passing through the center of gravity G of the vibrating element plate 10, the base 11, the first connecting arm 13a, the second connecting arm 13b, the first detection arm 12a, and the second detection arm 12b hardly vibrate.

[0038] Thus, under the state of buckling vibration of the first drive arms 14a and 14b and the second drive arms 15a and 15b, when an angular velocity ω about the Z-axis is applied to the vibrating element plate 10, a Coriolis force in the Y direction is applied to these drive arms respectively. With the help of this Coriolis force, such as... Figure 1 As shown by arrow B, the first connecting arm 13a and the second connecting arm 13b buckle in opposite directions in the Y direction. To eliminate this buckling vibration, as... Figure 1 As shown by the middle arrow C, the buckling vibration in the X direction of the first detection arm 12a and the second detection arm 12b is excited as a detection vibration. The charge generated between the pair of detection electrodes by this detection vibration is output as a detection signal. The angular velocity ω is calculated based on this detection signal. As described above, the angular velocity ω can be detected.

[0039] like Figure 2 As shown, the support member 20 is a substrate for TAB (Tape Automated Bonding) mounting. The support member 20 has a thin film 21 and a plurality of wires 22. The thin film 21 is an insulating substrate made of a resin material such as polyimide. A device hole 21a is provided in the center of the thin film 21. The plurality of wires 22 are provided corresponding to a pair of driving electrodes (not shown) and a pair of detection electrodes in the vibrating element plate 10. The plurality of wires 22 bend and extend from one side of the thin film 21 through the device hole 21a to the other side of the thin film 21. The plurality of wires 22 are connected to the base 11 of the vibrating element plate 10 via metal bumps 72. Through this connection, the plurality of wires 22 support the vibrating element plate 10 in a state of electrical connection with the pair of driving electrodes (not shown) and the pair of detection electrodes in the vibrating element plate 10.

[0040] like Figure 1As shown, circuit element 30 is an integrated circuit comprising a processor 31, a memory 32, a drive circuit 33, a detection circuit 34, a diagnostic circuit 35, and a fault detection circuit 36. The various circuits of circuit element 30 will be described in detail later. Furthermore, although not shown, circuit element 30 has multiple terminals for the aforementioned feedback signal DI, drive signal DQ, detection signals IQ1, and IQ2.

[0041] like Figure 2 As shown, package 40 is a container for housing the vibrating element 10, the support member 20, and the circuit element 30. Package 40 has a base 41, a cover 42, and a connecting member 43. The base 41 and the cover 42 are connected to each other via the connecting member 43. Figure 2 As shown, a space S is formed between the base 41 and the cover 42 to house the vibrating element 10, the support member 20, and the circuit element 30. The space S is, for example, under a reduced pressure of 10 Pa or less. Alternatively, an inert gas such as argon or nitrogen can be sealed in the space S.

[0042] The base 41 is a box-shaped component with a recess 411. The base 41 is roughly rectangular in shape when viewed from above. There are no particular limitations on the material used to construct the base 41; various ceramics, such as alumina, can be used. Figure 2 In the example shown, the base 41 has a flat substrate 41a and three frame-shaped substrates 41b, 41c, and 41d, which are stacked sequentially facing the +Z direction. Although not shown, wiring made of metal or the like is appropriately provided between the multiple substrates constituting the base 41. Furthermore, the shape of the base 41 or the number of substrates constituting the base 41 is not limited to... Figure 2 The examples shown can be arbitrary.

[0043] The recess 411 has a bottom surface 411a formed by the +Z direction side surface of the substrate 41a, a stepped surface 411b formed by the +Z direction side surface of the substrate 41b, and a stepped surface 411c formed by the +Z direction side surface of the substrate 41c.

[0044] The circuit element 30 is fixed to the bottom surface 411a via a fixing member 51, with the circuit element 30 housed inside the substrate 41b. The fixing member 51 is, for example, an adhesive comprising epoxy resin or acrylic resin. A plurality of internal terminals 61 are provided on the stepped surface 411b. The plurality of internal terminals 61 are electrically connected to a plurality of terminals (not shown) of the circuit element 30 via a plurality of wirings 71. The plurality of wirings 71 are, for example, made of bonding wires. A plurality of internal terminals 62 are provided on the stepped surface 411c. The plurality of internal terminals 62 are correspondingly provided to the plurality of wirings 22 of the support member 20. The plurality of wirings 22 of the support member 20 are fixed to the plurality of internal terminals 62 via a plurality of conductive fixing members 52. Through this fixing, the plurality of internal terminals 62 are electrically connected to a pair of driving electrodes (not shown) and a pair of detection electrodes in the vibrating element sheet 10. The plurality of fixing members 52 are, for example, made of solder, silver paste, conductive adhesive, etc.

[0045] Although not shown, a plurality of internal terminals 61 and a plurality of internal terminals 62 are suitably connected to a plurality of wiring disposed inside the base 41. Specifically, the plurality of wiring includes a plurality of wiring connecting a portion of the plurality of internal terminals 61 and a plurality of internal terminals 62, and a plurality of wiring connecting the remainder of the plurality of internal terminals 61 to a plurality of external terminals 63 on the outer surface of the base 41. The plurality of external terminals 63 are used when the physical quantity sensor 1 is mounted to an external device (not shown). The internal terminals 61, 62 and external terminals 63 are respectively constituted, for example, by forming a coating of nickel (Ni) or gold (Au) on a metallization layer such as tungsten (W) by plating or the like.

[0046] The cover 42, when viewed from above, has a roughly rectangular shape and is a plate-shaped component that closes the opening of the recess 411 of the base 41. The cover 42 can be made of any material that allows for welding to the base 41 or the connecting component 43; examples include Kova alloy, Alloy 42, and stainless steel. Furthermore, a nickel (Ni) coating can be appropriately applied to the surface of the cover 42 on the side facing the base 41, for example, through plating.

[0047] The joining component 43 is a frame-shaped component that connects the base 41 and the cover 42. The joining component 43 is also commonly referred to as a sealing ring. The joining component 43 is made of metals such as Kova alloy, 42 alloy, or stainless steel. Furthermore, a coating of nickel (Ni) or gold (Au) is appropriately applied to the surface of the joining component 43, for example, by plating. The joining component 43 is hermetically joined to the base 41 by brazing with silver solder or the like. Additionally, the joining component 43 is hermetically joined to the cover 42 by seam welding. Through these connections, the base 41 and the cover 42 are joined via the joining component 43. Alternatively, instead of the joining component 43, a metal film obtained by plating a coating of nickel (Ni) or gold (Au) onto a metallization layer such as tungsten (W) can be provided on the base 41.

[0048] A-3. Details of circuit components

[0049] Figure 3 This is a block diagram illustrating the structure of the circuit element 30 of the physical quantity sensor 1 in the embodiment. (As shown...) Figure 3 As shown, circuit element 30 includes processor 31, memory 32, drive circuit 33, detection circuit 34, diagnostic circuit 35, and fault detection circuit 36.

[0050] The processor 31 is a device that controls various parts of the physical quantity sensor 1 and processes various data. The processor 31 may be configured to include a processor such as a CPU. Alternatively, the processor 31 may be composed of a single processor or multiple processors. Furthermore, some or all of the functions of the processor 31 may be implemented using hardware such as a DSP, ASIC, PLD, or FPGA.

[0051] Memory 32 is a device for storing various programs, including program P1 executed by processor 31, and various data, including decision table T1 and predictive information D2 processed by processor 31. Memory 32 is configured, for example, to include semiconductor memory. Decision table T1 contains reference information D1. Furthermore, decision table T1 and predictive information D2 will be described in detail later.

[0052] The drive circuit 33 is a circuit that receives the feedback signal DI from the vibrating element plate 10 and outputs a drive signal DQ to drive the vibrating element plate 10. The drive circuit 33 includes an amplifier circuit 33a, a drive signal output circuit 33b, a gain control circuit 33c, and a synchronization signal output circuit 33d. The amplifier circuit 33a amplifies the feedback signal DI from the vibrating element plate 10 and converts it from a current signal to a voltage signal before outputting it. The amplifier circuit 33a is configured to include, for example, an operational amplifier, a feedback resistor, and a feedback capacitor. The drive signal output circuit 33b outputs the drive signal DQ based on the signal output from the amplifier circuit 33a. For example, if the waveform of the drive signal DQ is a rectangular wave or a sine wave, the drive signal output circuit 33b is configured to include a comparator. The gain control circuit (AGC) 33c controls the drive of the drive signal output circuit 33b based on the signal output from the amplifier circuit 33a, thereby controlling the amplitude of the drive signal DQ. The gain control circuit 33c is configured, for example, to include a full-wave rectifier that performs full-wave rectification of the signal from the amplifier circuit 33a and an integrator that performs integration processing on the output signal of the full-wave rectifier. The synchronization signal output circuit 33d outputs a synchronization signal based on the signal output from the amplifier circuit 33a to the detection circuit 34 and the diagnostic circuit 35, respectively. The synchronization signal output circuit 33d is configured, for example, to include: a comparator that binarizes the sinusoidal signal output from the amplifier circuit 33a to generate a rectangular wave synchronization signal; and a phase adjustment circuit that performs phase adjustment on the synchronization signal.

[0053] The detection circuit 34 detects the detection signals IQ1 and IQ2 from the vibrating element plate 10. The detection circuit 34 includes an amplifier circuit 34a, a synchronous detection circuit 34b, a filter section 34c, an analog-to-digital converter (AD / AD) circuit 34d, and a DSP section 34e. The amplifier circuit 34a differentially amplifies the detection signals IQ1 and IQ2 from the vibrating element plate 10 and converts them from charge signals to voltage signals before outputting them. The synchronous detection circuit 34b synchronously detects the signal from the amplifier circuit 34a based on the synchronization signal from the drive circuit 33. The filter section 34c is a low-pass filter that removes unwanted signal components from the signal output from the synchronous detection circuit 34b. The AD / AD converter 34d receives the signal from the synchronous detection circuit 34b via the filter section 34c and converts the input signal from an analog signal to a digital signal. The DSP section 34e performs digital signal processing on the digital signal from the AD / AD converter 34d, including digital filtering and digital correction.

[0054] The diagnostic circuit 35 is used to diagnose the detection circuit 34. For example, the diagnostic circuit 35 generates an analog angular velocity signal, etc., for use in diagnosing the detection circuit 34 and provides it to the detection circuit 34. Then, it performs a diagnosis based on the detection result of the analog angular velocity signal, etc., to determine whether the detection circuit 34, etc., is operating normally. Furthermore, the diagnostic circuit 35 can be configured as needed and may be omitted.

[0055] The fault detection circuit 36 ​​is a circuit that performs fault detection on the amplifier circuit 34a included in the detection circuit 34. For example, the fault detection circuit 36 ​​detects faults in the amplifier circuit 34a based on the output voltages of the two amplifiers that constitute the differential amplifier circuit in the amplifier circuit 34a, and determines whether these output voltages are within a specified voltage range. Furthermore, the fault detection circuit 36 ​​can be configured as needed and may be omitted.

[0056] In the circuit element 30 of the above structure, the processor 31 reads program P1 from memory 32 and executes it. Through this execution, the processor 31 functions as an acquisition unit 31a, a determination unit 31b, and a generation unit 31c.

[0057] The acquisition unit 31a acquires signal information SD related to the measured value of the drive signal DQ from the drive circuit 33. In this embodiment, the measured value is the voltage value of the drive signal DQ. The determination unit 31b reads reference information D1 from the memory 32 and determines the state up to the point where the physical quantity sensor 1 malfunctions based on the signal information SD and the reference information D1. More specifically, the determination unit 31b reads determination table T1 from the memory 32, compares the signal information SD and the reference information D1, and determines the phased state up to the point where the physical quantity sensor 1 malfunctions based on the comparison result. The generation unit 31c generates predictive information D2 based on the determination result of the determination unit 31b. More specifically, the generation unit 31c reads determination table T1 from the memory 32 and generates predictive information D2 related to the phased state up to the point where the physical quantity sensor 1 malfunctions based on determination table T1 and the determination result of the determination unit 31b.

[0058] As described above, the physical quantity sensor 1 has a package 40 that houses the vibrating element plate 10. Furthermore, the predictive information D2 includes information related to the prediction of a failure primarily caused by the vacuum level within the package 40. When the vacuum level within the package 40 decreases for some reason, the characteristics of the physical quantity sensor 1 also decrease, causing the physical quantity sensor 1 to fail soon afterward. Here, the decrease in vacuum level within the package 40 is usually slow. Therefore, the information related to the prediction of a failure primarily caused by the vacuum level within the package 40 is suitable for predictive information D2 related to the phased or continuous state until the physical quantity sensor 1 fails.

[0059] Figure 4 This is a graph showing the relationship between the vacuum level within the package 40 of the physical quantity sensor 1 and the driving voltage, which is the voltage value of the driving signal DQ. For example... Figure 4 As shown, the lower the vacuum level within the package 40, i.e., the greater the pressure in the space S of the package 40, the higher the driving voltage. Here, when the voltage signal from the amplifier circuit 33a is within the adjustable range of the gain control circuit 33c, the driving voltage remains constant at or near a predetermined value. Therefore, in this case, the detection sensitivity of the physical quantity sensor 1 is maintained within the desired range. On the other hand, when the voltage signal from the amplifier circuit 33a is outside the adjustable range of the gain control circuit 33c, the driving voltage deviates from the predetermined value. Therefore, in this case, the detection sensitivity of the physical quantity sensor 1 decreases. Thus, in this embodiment, the driving voltage, i.e., the voltage value of the driving signal DQ, is used as the measured value of the driving signal DQ. Then, the determination unit 31b determines the state until the physical quantity sensor 1 malfunctions based on the signal information SD and the reference information D1 related to the voltage value of the driving signal DQ. More specifically, the determination unit 31b uses the determination table T1 as follows to determine the state until the physical quantity sensor 1 malfunctions.

[0060] Figure 5 This is a diagram showing an example of a decision table T1 that represents the relationship between the reference information D1 and the decision result. Figure 6 This is a diagram showing another example of a decision table T1 that represents the relationship between reference information D1 and the decision result. Decision unit 31b, for example, uses... Figure 5 or Figure 6 The judgment table T1 shown determines the state until the physical quantity sensor 1 fails. Figure 5 or Figure 6 The judgment table T1 shown represents the correspondence between each benchmark value in the benchmark information D1 and the judgment result. Furthermore, the range of values ​​in judgment table T1 is not limited to... Figure 5 and Figure 6 The examples shown can be arbitrary.

[0061] In use Figure 5 In the case of the determination table T1 shown, the determination unit 31b determines that the driving voltage is above V1 and below V2 to be at the normal level. Furthermore, the determination unit 31b determines that the driving voltage is below V1 or above V3 to be at the fault level. Additionally, the determination unit 31b determines that the driving voltage is above V2 and below V3 to be at the predicted fault level. Here, V1 is a value slightly lower than the reference value Va, for example, approximately 0.9 times Va. V2 is a value slightly higher than the reference value Va, for example, approximately 1.2 times Va. V3 is a value higher than V2, approximately 1.3 times Va.

[0062] In use Figure 6 In the case of the determination table T1 shown, the determination unit 31b determines that the driving voltage is at least 1.0 times and less than 1.2 times the reference value Va, indicating a normal level. Furthermore, the determination unit 31b determines that the driving voltage is at least 0.8 times or more than 1.4 times the reference value Va, indicating a fault level. Additionally, the determination unit 31b determines that the driving voltage is at least 0.9 times and less than 1.0 times, or at least 1.2 times and less than 1.3 times the reference value Va, indicating a predicted fault level 1. Furthermore, the determination unit 31b determines that the driving voltage is at least 0.8 times and less than 0.9 times, or at least 1.3 times and less than 1.4 times the reference value Va, indicating a predicted fault level 2, which is closer to a fault state than predicted fault level 1. Here, the range of 0.9 times or more but less than 1.0 times, or 1.2 times or more but less than 1.3 times, represents the first range relative to the reference value Va. The range of 0.8 times or more but less than 0.9 times, or 1.3 times or more but less than 1.4 times, represents the second range relative to the reference value Va, which is different from the first range. Thus, when using... Figure 6 In the case of the determination table T1 shown, the reference information D1 includes a first range and a second range. When the measured value of the drive signal DQ is within the first range, the processor 31 outputs prediction level 1 as the first prediction information; when the measured value of the drive signal DQ is within the second range, it outputs prediction level 2 as the second prediction information, which is different from the first prediction information. Therefore, prediction information D2 related to the stage state before the failure of the physical quantity sensor 1 can be output.

[0063] Alternatively, the reference information D1 or decision table T1 can be pre-stored in the memory 32 before the physical quantity sensor 1 leaves the factory, or it can be stored in the memory 32 by the user when using the physical quantity sensor 1. However, it is preferable that the reference information D1 or decision table T1 is pre-stored in the memory 32. In this case, it is not necessary to generate the reference information D1 after the physical quantity sensor 1 is started. As a result, the predictive information D2 can be output quickly immediately after the physical quantity sensor 1 is started.

[0064] Based on the determination result described above, the generation unit 31c generates predictive information D2. That is, the generation unit 31c generates predictive information D2 when the determination result of the determination unit 31b is a predictive level, predictive level 1, or predictive level 2. Furthermore, when the determination result of the determination unit 31b is a fault level, the generation unit 31c generates fault information indicating that the physical quantity sensor 1 is in a fault state. Additionally, depending on the degree of fault level in the determination result, this fault information can also be described as "predictive information."

[0065] The timing of generating and outputting the aforementioned predictive information D2 is not particularly limited, but it is preferable to include at least the start-up of the physical quantity sensor 1. That is, it is preferable that the processor 31 obtains the signal information of the drive signal DQ when the physical quantity sensor 1 is started and outputs the predictive information D2. In this case, the possibility of the physical quantity sensor 1 being used in a faulty state can be reduced. In addition, the generation and output of the predictive information D2 can also be performed continuously throughout the operation of the physical quantity sensor 1.

[0066] Figure 7 This is a flowchart illustrating the operation of the sensor fault prediction system 100 according to an embodiment. Figure 7 As shown, firstly, the acquisition unit 31a acquires information related to the driving voltage, and the determination unit 31b compares the driving voltage with the reference value in the reference information D1 to determine the state of the physical quantity sensor 1 (step S1). Then, the generation unit 31c determines whether the determination result is at a normal level (step S2). If the determination result is at a normal level, the process returns to step S1.

[0067] If the determination result is not at the normal level, the generation unit 31c determines whether the determination result is at the predictable level (step S3). If the determination result is at the predictable level, the generation unit 31c generates predictable information D2 and stores it in the memory 32 (step S4). Then, it returns to step S1.

[0068] If the determination result is not a predicted level, the generation unit 31c determines whether the determination result is a fault level (step S5). If the determination result is not a fault level, it returns to step S1. On the other hand, if the determination result is a fault level, the generation unit 31c generates fault information and stores it in the memory 32 (step S6), and then ends the operation of the physical quantity sensor 1.

[0069] The sensor fault prediction system 100 described above includes a processor 31 and a memory 32. The memory 32 stores reference information D1 related to a reference value of the drive signal DQ in the physical quantity sensor 1, which includes the vibrating element plate 10. Then, the processor 31 acquires signal information SD related to the measured value of the drive signal DQ, and based on the signal information SD and the reference information D1, outputs prediction information D2 related to the phased state until the physical quantity sensor 1 fails. In the sensor fault prediction system 100 described above, since the prediction information D2 related to the phased or continuous state until the physical quantity sensor 1 fails is output, the state until the physical quantity sensor 1 fails can be detected in advance.

[0070] Here, the vibrating element 10 is driven to vibrate according to the drive signal DQ, and outputs detection signals IQ1 and IQ2 based on physical quantities. In this embodiment, the physical quantity sensor 1, in addition to the vibrating element 10, also includes the processor 31 and memory 32 described above. Therefore, the processing in the device equipped with the physical quantity sensor 1 can be reduced.

[0071] B. Electronic devices

[0072] Figure 8 This is a perspective view schematically showing the structure of a mobile or notebook-type personal computer 1100, an example of an electronic device. In this figure, the personal computer 1100 consists of a main body 1104 with a keyboard 1102 and a display unit 1106 with a display unit 1108. The display unit 1106 is supported by a hinge structure and is rotatable relative to the main body 1104. The personal computer 1100 incorporates the aforementioned physical quantity sensor 1 and sensor fault prediction system 100.

[0073] Figure 9 This is a top view schematically showing the structure of a smartphone 1200, an example of an electronic device. In this figure, the smartphone 1200 has multiple operation buttons 1202, an earpiece 1204, and a microphone (not shown). A display unit 1208 is arranged between the operation buttons 1202 and the earpiece 1204. The smartphone 1200 incorporates the aforementioned physical quantity sensor 1 and sensor fault prediction system 100.

[0074] Figure 10 This is a perspective view that schematically illustrates the structure of a digital camera 1300 as an example of an electronic device. The connection to external devices is also simply shown in the figure. The digital camera 1300 generates an image signal by photoelectric conversion of the optical image of the subject using an imaging element such as a CCD (Charge Coupled Device).

[0075] On the back of the housing 1302 in the digital camera 1300, a display unit 1310 is provided for displaying the shooting signal from the CCD. The display unit 1310 functions as a viewfinder that displays the subject as an electronic image. Additionally, on the front side (rear side in the figure) of the housing 1302, a light-receiving unit 1304 including an optical lens (camera optical system) and a CCD is provided.

[0076] When the photographer confirms the image of the subject displayed on the display unit 1310 and presses the shutter button 1306, the CCD's shooting signal at that moment is transmitted to the memory 1308 and saved. Furthermore, in this digital camera 1300, a video signal output terminal 1312 and a data communication input / output terminal 1314 are provided on the side of the housing 1302. Moreover, as shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312, and a personal computer 1440 is connected to the data communication input / output terminal 1314, respectively, as needed. And, through a predetermined operation, the shooting signal stored in the memory 1308 is output to the television monitor 1430 or the personal computer 1440. The digital camera 1300 described above incorporates the aforementioned physical quantity sensor 1 and sensor fault prediction system 100.

[0077] The above-described electronic device includes a sensor fault prediction system 100. Therefore, it is possible to perform appropriate pre-fault handling based on the prediction information D2 before the physical quantity sensor 1 malfunctions. Examples of such appropriate handling include, for instance, facilitating maintenance through display or sound when the prediction information D2 indicates a prediction level. Here, when outputting fault information, for example, illuminating a warning light may be performed. Furthermore, part or all of the sensor fault prediction system 100 may be integrated with other components of the electronic device.

[0078] In addition, as electronic devices equipped with physical quantity sensor 1, besides the aforementioned personal computers, smartphones, and digital cameras, other examples include portable telephones, tablet terminals, watches, vehicle posture detection devices, indicating devices, head-mounted displays, inkjet printers, personal laptops, televisions, video cameras, videotape recorders, navigation devices, pagers, electronic notebooks, electronic dictionaries, calculators, video game devices, game controllers, word processors, workstations, video phones, anti-theft television monitors, electronic binoculars, POS (Point of Sale) terminals, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasound diagnostic devices, electronic endoscopes, fish detectors, various measuring devices, instruments, and flight simulators.

[0079] C. Moving body

[0080] Figure 11This is a perspective view of a car 1500, which is a schematic example of a moving body. In this view, the aforementioned physical quantity sensor 1 and sensor fault prediction system 100 are built into the car 1500. The physical quantity sensor 1 can be widely used in electronic control units (ECUs) 1501 such as keyless entry systems, anti-theft devices, navigation systems, air conditioning, anti-lock braking systems (ABS), airbags, tire pressure monitoring systems (TPMS), engine controllers, battery monitors for hybrid or electric vehicles, and vehicle posture control systems. Furthermore, as a moving body equipped with electronic devices, besides cars, examples include vehicles, aircraft, rockets, and ships. Additionally, part or all of the sensor fault prediction system 100 can be integrated with other structures of the moving body.

[0081] The aforementioned mobile body is equipped with a sensor fault prediction system 100. Therefore, based on the prediction information D2, appropriate pre-emptive measures can be taken before the physical quantity sensor 1 malfunctions. In the case of a car, such appropriate pre-emptive measures include, for example, illuminating a warning light in the car's electronic control unit 1501 when the prediction information D2 indicates prediction level 1, and promoting maintenance through displays or sounds on a navigation system or similar device when the prediction information D2 indicates prediction level 2. Here, when outputting fault information, for example, illuminating the warning light is performed.

[0082] Furthermore, when the moving body is an aerial vehicle such as a drone, for example, if the prediction information D2 indicates prediction level 1, only the warning light is illuminated; if the prediction information D2 indicates prediction level 2, in addition to illuminating the warning light, the operating conditions are also limited. Here, when a fault information is output, for example, the fault light is illuminated, and the movement of the aerial vehicle is prohibited.

[0083] D. Variations

[0084] The sensor fault prediction system, sensor fault prediction method, physical quantity sensor, electronic device, and moving body of the present invention have been described above with reference to the illustrated embodiments, but the present invention is not limited to these. Furthermore, the structure of each part of the present invention can be replaced with any structure that performs the same function as the above embodiments, and any structure can also be added. In addition, the present invention can also combine any structures of the above embodiments with each other.

[0085] In the above embodiment, a case where a driving voltage, which is the voltage value of the driving signal, is used to generate predictive information is illustrated. However, this is not limited to this example. For instance, a resistance value based on the current value of the driving signal can also be used as a measured value to generate predictive information. When the vacuum level within the package housing the vibrating element of the physical quantity sensor decreases for some reason, the resistance value based on the current value of the driving signal increases as the vacuum level decreases. Therefore, by setting the reference value as the voltage value and the resistance value based on the current value of the driving signal as the measured value, predictive information related to the prediction of a physical quantity sensor malfunction primarily caused by the vacuum level within the package can be output. This resistance value is, for example, the equivalent series resistance value in the equivalent circuit of the vibrating element, i.e., the so-called CI (crystal impedance) value. Furthermore, the reference value is appropriately set.

[0086] Furthermore, while the above embodiment illustrates the use of a drive signal to generate predictive information, it is not limited to this example; for instance, a detection signal can also be used to generate predictive information. For example, regardless of the presence or absence of a physical quantity, the value of the vibration component of the leakage vibration contained in the detection signal, i.e., the value of the so-called zero-point signal, varies depending on the state until the physical quantity sensor malfunctions. Therefore, the value of this zero-point signal can also be used to generate predictive information. Additionally, a reference value is appropriately set.

[0087] Furthermore, the above embodiment illustrates a case where the predicted information is intermittent information up to the point where the physical quantity sensor malfunctions. However, it is not limited to this example; the predicted information can also be continuous information up to the point where the physical quantity sensor malfunctions. In this case, for example, any calculation that allows the predicted information to change continuously based on the difference or ratio between the measured value of the drive signal or detection signal and the reference value is sufficient.

[0088] Furthermore, while the above embodiments illustrate the generation of predictive information by circuit elements built into the physical quantity sensor, the method is not limited to this example. For instance, an external device of the physical quantity sensor could generate predictive information by obtaining measured values ​​of the drive signal or detection signal of the vibrating element plate from the physical quantity sensor. This external device could, for example, include… Figure 1 The device shown includes a processor 101 and a memory 102.

[0089] Furthermore, while the above embodiment exemplifies a case where the vibrating element sheet is made of a piezoelectric material, the material of the vibrating element sheet is not limited to this example. For instance, it could also be a non-piezoelectric material such as silicon or quartz. In this case, for example, it is sufficient to simply place the piezoelectric element on a substrate made of a non-piezoelectric material. Additionally, when the vibrating element sheet is made of silicon, known microfabrication techniques such as etching can be used to manufacture a vibrating element sheet with high dimensional accuracy at a relatively low cost.

[0090] Furthermore, while the above embodiments illustrate the use of piezoelectric actuation as the driving method for the vibrating element, the driving method for the vibrating element is not limited to this example; for example, it could also be electrostatic actuation or electromagnetic actuation. Similarly, while the above embodiments illustrate the use of piezoelectric detection as the detection method for the vibrating element, the detection method for the vibrating element is not limited to this; for example, it could also be electrostatic capacitance detection, piezoelectric resistance detection, or electromagnetic detection.

[0091] Furthermore, in the above embodiment, a case where the vibrating element is a double-T type sensor element is illustrated, but the vibrating element is not limited to this example. For example, it could also be other sensor element elements such as H-type or tuning fork type. In addition, the support member supporting the vibrating element on the package is not limited to the component for TAB mounting described above. For example, it could also be integrally constructed from the same material as the vibrating element.

[0092] Furthermore, while the above embodiment exemplifies a gyroscope sensor that detects angular velocity, it is not limited to this example. For instance, the physical quantity sensor could also be an acceleration sensor that detects acceleration as a physical quantity.

[0093] Furthermore, in the above embodiments, a structure in which the base is box-shaped and the cover is plate-shaped is illustrated, but the embodiment is not limited to this example. For example, the base may be plate-shaped and the cover may be box-shaped or cap-shaped.

Claims

1. A physical quantity sensor, characterized in that, The physical quantity sensor includes: Sensor component chip; Circuit elements including memory; and The package contains the sensor chip and the circuit components within its internal space. The package includes: A base that supports the sensor element chip and the circuit elements; and The cover engages with the base in a manner that makes the space airtight. The circuit element includes a determination unit that determines whether it is in a faulty state or a state where a fault will not occur, based on changes in spatial pressure. The determination unit determines the state up to the occurrence of the fault based on the reference information (D1) stored in the memory and related to the reference value, and the signal information (SD) output from the drive circuit.

2. The physical quantity sensor according to claim 1, characterized in that, The space is in a depressurized state.

3. The physical quantity sensor according to claim 2, characterized in that, The sensor element chip includes: The drive arm, which is equipped with drive electrodes; and The detection arm is equipped with detection electrodes.

4. The physical quantity sensor according to claim 3, characterized in that, The circuit element includes: A driving circuit, which is connected to the driving electrode; and A detection circuit, which is connected to the detection electrode.

5. The physical quantity sensor according to claim 4, characterized in that, The signal information (SD) is information related to the voltage value of the drive signal that drives the drive arm.

6. The physical quantity sensor according to claim 5, characterized in that, The baseline information (D1) includes: Information related to a first range representing a range relative to the reference value; and Information related to a second range representing a range relative to the reference value, the second range being a range different from the first range.

7. The physical quantity sensor according to claim 6, characterized in that, The determination unit determines a fault at a first predictive level when the signal information (SD) is within the first range, and determines a fault at a second predictive level that is different from the first predictive level when the signal information (SD) is within the second range.

8. An electronic device, wherein, The electronic device includes a physical quantity sensor according to any one of claims 1 to 7.

9. A mobile body, wherein, The moving body includes a physical quantity sensor according to any one of claims 1 to 7.

10. A physical quantity sensor, characterized in that, The physical quantity sensor includes: Vibrating elements; Circuit elements including memory; and The package contains the vibrating element and the circuit elements within its storage space. The vibrating element comprises: Drive electrodes; and Detection electrode, The circuit element includes: A driving circuit, which is electrically connected to the driving electrode; A detection circuit, which is electrically connected to the detection electrode; and The determination unit detects changes in pressure within the storage space by detecting the voltage of the drive signal from the drive circuit. The determination unit determines the state up to the point of failure based on the reference information (D1) stored in the memory and related to the reference value, and the signal information (SD) output from the drive circuit.

11. The physical quantity sensor according to claim 10, characterized in that, The determination unit determines whether the system is in a faulty state or in a state where a fault will not occur until the pressure changes.

12. The physical quantity sensor according to claim 11, characterized in that, The storage space is in a depressurized state.

13. The physical quantity sensor according to claim 12, characterized in that, The signal information (SD) is information related to the voltage value of the drive signal.

14. The physical quantity sensor according to claim 13, characterized in that, The baseline information (D1) includes: Information related to a first range representing a range relative to the reference value; and Information related to a second range representing a range relative to the reference value, the second range being a range different from the first range.

15. The physical quantity sensor according to claim 14, characterized in that, The determination unit determines a fault at a first predictive level when the signal information (SD) is within the first range, and determines a fault at a second predictive level that is different from the first predictive level when the signal information (SD) is within the second range.

16. An electronic device, wherein, The electronic device includes a physical quantity sensor according to any one of claims 10 to 15.

17. A mobile body, wherein, The moving body includes a physical quantity sensor according to any one of claims 10 to 15.

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