Shock Logger

Abstract

We provide an impact logger that can achieve high impact detection accuracy. [Solution] The impact logger comprises a circuit element comprising an acceleration sensor, a timing circuit for generating time data, a sensor circuit for processing the output signal of the acceleration sensor, and a memory circuit for storing the processed data processed by the sensor circuit and the time data in association, and a package for housing the acceleration sensor and the circuit element, wherein the natural vibration frequency is less than 33 Hz or greater than 100 Hz. Preferably, the natural vibration frequency is less than 25 Hz or greater than 1 kHz, and more preferably less than 20 Hz or greater than 10 kHz.

Description

Technical Field

[0001] The present invention relates to an impact logger.

Background Art

[0002] Patent Document 1 describes an impact detection device that can detect impacts applied to transported goods. This impact detection device has a configuration in which an acceleration sensor, a real-time clock, an operation switch, an LED, a memory unit, a wireless communication unit, a control unit, and a battery are housed in a semi-transparent or transparent resin housing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, Patent Document 1 does not consider at all the natural vibration frequency (resonance frequency) of the impact detection device. Therefore, if an impact with a frequency close to the natural vibration frequency of the impact detection device is applied to the transported goods, the impact detection device will resonate, and as a result, the impact detection device will detect an impact larger than the actual impact applied. Therefore, there is a risk that the detection accuracy of the impact will decrease.

Means for Solving the Problems

[0005] The impact logger of the present invention includes an acceleration sensor, a timing circuit that generates time data, a sensor circuit that processes the output signal of the acceleration sensor, and a memory circuit that stores the processed data processed by the sensor circuit and the time data in association with each other, and is a circuit element including these components, and a package that houses the acceleration sensor and the circuit element. The natural frequency is less than 33 Hz or greater than 100 Hz. [Brief explanation of the drawing]

[0006] [Figure 1] This is a top view of the impact logger according to the first embodiment. [Figure 2] This is a cross-sectional view along line AA in Figure 1. [Figure 3] This is an exploded perspective view showing the arrangement of each part within the recess. [Figure 4] This is a top view of the vibrating element. [Figure 5] This is a top view of the accelerometer. [Figure 6] This is a block diagram of the circuitry provided by a circuit element. [Figure 7] This figure shows an example of event data. [Figure 8] This is a diagram showing the vibration waveform of an impact. [Figure 9] This is a top view of the impact logger according to the second embodiment. [Figure 10] This is a cross-sectional view along line BB in Figure 9. [Figure 11] This is a cross-sectional view of the impact logger according to the third embodiment. [Figure 12] This is a top view of the impact logger according to the fourth embodiment. [Figure 13] This is a cross-sectional view along line CC in Figure 12. [Figure 14] This is a top view of the impact logger according to the fifth embodiment. [Figure 15] This is a top view of the impact logger according to the sixth embodiment. [Figure 16] This is a cross-sectional view of the impact logger according to the seventh embodiment. [Modes for carrying out the invention]

[0007] The impact logger of the present invention will be described in detail below based on the embodiments shown in the attached drawings. For convenience of explanation, in all figures except Figures 6 to 8, the three mutually orthogonal axes are shown as the X-axis, Y-axis, and Z-axis. The direction along the X-axis is also called the "X-axis direction," the direction along the Y-axis is also called the "Y-axis direction," and the direction along the Z-axis is also called the "Z-axis direction." Furthermore, the side of the arrow on each axis is also called the "positive side," and the opposite side is also called the "negative side." In addition, the Z-axis is aligned vertically, and the side with the arrow is also called "up," and the opposite side is also called "down."

[0008] <First Embodiment> Figure 1 is a top view of the impact logger according to the first embodiment. Figure 2 is a cross-sectional view taken along line AA in Figure 1. Figure 3 is an exploded perspective view showing the arrangement of each part within the recess. Figure 4 is a top view of the vibration element. Figure 5 is a top view of the acceleration sensor. Figure 6 is a block diagram showing the circuitry provided by the circuit element. Figure 7 is a diagram showing an example of event data. Figure 8 is a diagram showing the vibration waveform of the impact.

[0009] The impact logger 1 shown in Figure 1 is installed on the goods being transported, which are the target of impact measurement. It detects impacts applied to the goods and stores the detected impacts along with the time they occurred. Using such an impact logger 1, it is possible to confirm when and to what extent an impact was applied to the goods during transport.

[0010] Therefore, from the perspective of the party requesting the transportation of goods (for the sake of explanation, let's call them the product manufacturer), if, for example, the goods are damaged or malfunctioned during transportation, it becomes possible to clarify the date and time of the damage or malfunction, the cause of the damage or malfunction, and who is responsible, making it easier to deal with the transporter afterward. Furthermore, by checking the impacts applied to the goods during transportation, it becomes possible to review the mechanical design of the goods and improve them to make them less prone to malfunction. In addition, it becomes possible to review the shape and size of the cushioning material used to protect the goods from impact, and for example, if the cushioning material can be made smaller as a result of the review, the cost of the goods and transportation costs can be reduced accordingly.

[0011] On the other hand, from the perspective of the transporter who transports the goods, it can be effectively used as evidence to prove that there is no cause such as damage or failure on their part. In addition, it can be proven by the shock logger 1 that the impact applied during transportation is much less than that of competitors, and by appealing to the high transportation quality for this reason, differentiation from other transporters can also be achieved.

[0012] As described above, the shock logger 1 brings various benefits to both the shipper side and the transporter side. In particular, the shock logger 1 of the present embodiment is inexpensive and small-sized compared to conventional shock loggers (for example, the shock detection device described in Patent Document 1), and there is almost no increase in cost or size due to mounting the shock logger 1. Therefore, it becomes a shock logger 1 with extremely high convenience.

[0013] As shown in FIG. 1, the shock logger 1 includes a support substrate 2, a vibration element 3, an acceleration sensor 4, a circuit element 5, a battery 6, and a package 7 that houses each of these components. Such a shock logger 1 is mounted on a commodity, for example, such that the positive side in the Z-axis direction faces the upper side in the vertical direction during transportation.

[0014] [Package 7] First, the package 7 will be described. As shown in FIGS. 1 to 3, the package 7 includes a cavity-shaped base 71 having a recess 711 that opens on the upper surface, and a plate-shaped lid 72 that is joined to the upper surface of the base 71 via a seam ring 73 and closes the opening of the recess 711. According to such a configuration, the structure of the package 7 becomes simple. In addition, the package 7 has an internal space, and the support substrate 2, the vibration element 3, the acceleration sensor 4, the circuit element 5, and the battery 6 are housed in this internal space. Further, the internal space is hermetically sealed and is in a decompressed state, preferably a state closer to a vacuum. Thereby, the viscous resistance of the internal space is reduced, and the vibration element 3 can be efficiently oscillated. However, the atmosphere of the internal space is not particularly limited.

[0015] The constituent material of the base 71 is not particularly limited, but various ceramics such as aluminum oxide can be used. The constituent material of the lid 72 is also not particularly limited, but it is preferable that it be a material whose coefficient of thermal expansion is similar to that of the constituent material of the base 71. For example, if the constituent material of the base 71 is ceramic, it is preferable to use an alloy such as Kovar. With such a configuration, a rigid package 7 is formed, and the mechanical strength of the impact logger 1 is increased. Furthermore, as will be described later, each part can be electrically connected by internal wiring (not shown) formed in the base 71, so a wiring board or the like for electrical connections is unnecessary. Therefore, the impact logger 1 can be made lighter and smaller.

[0016] Furthermore, as shown in Figure 2, the base 71 has a bottom surface 712 of the recess 711, a first stepped surface 713 located above the bottom surface 712 (positive Z-axis direction) and parallel to the bottom surface 712, and a second stepped surface 714 located above the first stepped surface 713 (positive Z-axis direction) and parallel to the bottom surface 712. Also, as shown in Figure 1, in a plan view from the Z-axis direction, the first stepped surface 713 is frame-shaped, surrounding the bottom surface 712. Also, in a plan view from the Z-axis direction, the second stepped surface 714 is divided into two parts and arranged opposite each other in the Y-axis direction, with the bottom surface 712 in between. Furthermore, the second stepped surface 714 is positioned biased towards the negative X-axis direction. The circuit element 5 and battery 6 are arranged side by side in the X-axis direction on the bottom surface 712, the acceleration sensor 4 is placed on the upper surface of the circuit element 5, the support substrate 2 is placed on the second stepped surface 714, and the vibration element 3 is placed on the upper surface of the support substrate 2. However, the shapes of the first and second stepped surfaces 713 and 714 are not particularly limited.

[0017] As shown in Figure 1, a plurality of first internal terminals 741 are arranged on the first stepped surface 713, and a plurality of second internal terminals 742 are arranged on the second stepped surface 714. As shown in Figure 2, a plurality of external terminals 743 are arranged on the lower surface of the base 71. Each of the plurality of first internal terminals 741 is electrically connected to a predetermined second internal terminal 742 or a predetermined external terminal 743 via internal wiring (not shown) formed in the base 71. Each first internal terminal 741 is electrically connected to the circuit element 5 via a conductive wire W (bonding wire), and each second internal terminal 742 is electrically connected to the vibration element 3 via conductive bonding member B1 and wiring 21 and 22 (described later) formed on the support substrate 2. The number and arrangement of the first and second internal terminals 741, 742 and the external terminals 743 are not particularly limited and can be set appropriately according to, for example, the number of terminals of the circuit element 5 and the vibration element 3.

[0018] The size of package 7 is not particularly limited, but it is preferable that the length in the X-axis direction × the length in the Y-axis direction be 10 mm or less × 10 mm or less. This makes the impact logger 1 sufficiently compact. In this embodiment, it is approximately 7 mm × 5 mm.

[0019] [Vibration element 3] As shown in Figure 4, the vibrating element 3 is a tuning fork-type quartz oscillator. The vibrating element 3 is made by patterning a Z-cut quartz substrate to a predetermined shape by etching or the like, and has a base portion 30, a pair of vibrating arms 31 and 32 extending from the base portion 30 in the negative direction in the Y-axis direction, and a pair of L-shaped support arms 33 and 34 extending from the base portion 30. The vibrating element 3 is joined to the upper surface of the support substrate 2 via conductive bonding members B2 at the tips of the support arms 33 and 34. The vibrating element 3 also has first excitation electrodes E1 arranged on the upper and lower surfaces of the vibrating arm 31 and on both sides of the vibrating arm 32, and second excitation electrodes E2 arranged on both sides of the vibrating arm 31 and on the upper and lower surfaces of the vibrating arm 32. Furthermore, the first excitation electrode E1 is electrically connected to a first connection terminal P1 located at the tip of the support arm 33 via wiring (not shown), and the second excitation electrode E2 is electrically connected to a second connection terminal P2 located at the tip of the support arm 34 via wiring (not shown). In such a vibrating element 3, when a drive signal (alternating voltage) is applied between the first and second excitation electrodes E1 and E2 via the first and second connection terminals P1 and P2, the vibrating arms 31 and 32 vibrate in plane by repeatedly moving closer to and further apart from each other.

[0020] The above describes the vibration element 3, but the configuration of the vibration element 3 is not particularly limited. For example, it may be configured using a quartz substrate cut with a cut angle other than Z-cut, such as AT-cut or SC-cut.

[0021] [Support substrate 2] As shown in Figure 1, the support substrate 2 is a roughly rectangular plate with thickness along the Z-axis, and is joined to the second stepped surface 714 at its outer edge via a conductive bonding member B1. The support substrate 2 is located below the vibrating element 3 and supports the vibrating element 3 from below at its central portion. In addition to its function of electrically relaying power between the vibrating element 3 and the base 71, the support substrate 2 also has the function of absorbing or mitigating stress caused by deformation of the base 71 and thermal stress caused by differences in the coefficient of linear expansion, thereby making it difficult for such stress to be transmitted to the vibrating element 3.

[0022] Such a support substrate 2 is made of a quartz substrate, just like the vibrating element 3. This results in a support substrate 2 with high mechanical strength. Furthermore, by making the support substrate 2 from the same quartz substrate as the vibrating element 3, the coefficients of linear expansion of the support substrate 2 and the vibrating element 3 can be made almost equal. Therefore, thermal stress caused by the difference in their coefficients of linear expansion is virtually eliminated between the support substrate 2 and the vibrating element 3, making the vibrating element 3 less susceptible to stress. As a result, the driving of the vibrating element 3 becomes more stable. In particular, the support substrate 2 is made of the same Z-cut quartz substrate as the vibrating element 3. Also, the orientation of the crystal axis matches that of the vibrating element 3. Since quartz has different coefficients of linear expansion in the X-axis (electrical axis), Y-axis (mechanical axis), and Z-axis (optical axis) directions, by making the support substrate 2 and the vibrating element 3 the same cut angle and aligning the orientation of their crystal axes, the aforementioned thermal stress is less likely to occur between the support substrate 2 and the vibrating element 3. As a result, the vibrating element 3 becomes even less susceptible to stress, and the driving of the vibrating element 3 becomes even more stable.

[0023] The support substrate 2 is not limited to this; for example, it may be formed from a quartz substrate with the same cut angle as the vibrating element 3, but the direction of the crystal axis may be different from that of the vibrating element 3. Furthermore, the support substrate 2 may be formed from a quartz substrate with a different cut angle than that of the vibrating element 3. Also, the support substrate 2 does not have to be formed from a quartz substrate; for example, it can be formed from a silicon substrate, a resin substrate, etc. Furthermore, for example, it may be a substrate for TAB (Tape Automated Bonding) mounting having a support substrate and leads extending from the support substrate.

[0024] Furthermore, the support substrate 2 is provided with two wires 21 and 22 for electrically connecting the first and second connection terminals P1 and P2 of the vibration element 3 to the second internal terminal 742 located on the second stepped surface 714 of the base 71. One end of the wires 21 and 22 is electrically connected to the second internal terminal 742 via a conductive bonding member B1, and the other end of the wires 21 and 22 is electrically connected to the first and second connection terminals P1 and P2 via a conductive bonding member B2. The bonding members B1 and B2 are not particularly limited as long as they possess both conductivity and bonding properties. For example, various metal bumps such as gold bumps, silver bumps, copper bumps, and solder bumps, or conductive adhesives such as polyimide-based, epoxy-based, silicone-based, and acrylic-based adhesives in which a conductive filler such as silver filler is dispersed can be used.

[0025] [Accelerometer 4] The acceleration sensor 4 is a three-axis acceleration sensor capable of detecting acceleration in the X-axis direction (Ax), acceleration in the Y-axis direction (Ay), and acceleration in the Z-axis direction (Az). The acceleration sensor 4 is a silicon MEMS (Micro Electro Mechanical Systems). Therefore, it is possible to miniaturize the acceleration sensor 4.

[0026] As shown in Figure 5, the acceleration sensor 4 comprises a package 41 and an X-axis acceleration sensor element 42x, a Y-axis acceleration sensor element 42y, and a Z-axis acceleration sensor element 42z housed in the package 41. The package 41 also comprises a base 411 supporting each of the sensor elements 42x, 42y, and 42z, and a lid 413 bonded to the upper surface of the base 411, housing each of the sensor elements 42x, 42y, and 42z between itself and the base 411. The base 411 is larger than the lid 413, and a portion of its upper surface (the positive end in the Y-axis direction) is exposed to the outside from the lid 413. Multiple connection terminals P3, electrically connected to the sensor elements 42x, 42y, and 42z, are arranged on the portion of the upper surface of the base 411 that is exposed from the lid 413.

[0027] Such an acceleration sensor 4 can be formed, for example, by the steps of forming a base 411 from one silicon layer (handle layer) of an SOI (silicon on insulator) substrate, forming each sensor element 42x, 42y, and 42z from the other silicon layer (device layer), and bonding a lid 413 formed from the silicon substrate to the base 411. With this configuration, the acceleration sensor 4 can be manufactured using a manufacturing method compliant with silicon semiconductor processes.

[0028] The following is a brief explanation of the X-axis accelerometer element 42x, the Y-axis accelerometer element 42y, and the Z-axis accelerometer element 42z.

[0029] The X-axis acceleration sensor element 42x has a fixed comb-tooth electrode fixed to the base 411 and a movable comb-tooth electrode positioned to mesh with the fixed comb-tooth electrode and displaceable in the X-axis direction relative to the base 411, with the fixed comb-tooth electrode and the movable comb-tooth electrode facing each other in the X-axis direction. When an acceleration Ax in the X-axis direction is applied to the X-axis acceleration sensor element 42x, the movable comb-tooth electrode is displaced in the X-axis direction, and the capacitance between the fixed comb-tooth electrode and the movable comb-tooth electrode changes according to this displacement. Therefore, this change in capacitance can be taken as an output signal from the connection terminal P3, and the acceleration Ax can be detected based on this output signal. However, the configuration of the X-axis acceleration sensor element 42x is not particularly limited as long as it can detect the acceleration Ax.

[0030] The Y-axis acceleration sensor element 42y is configured by rotating the X-axis acceleration sensor element 42x by 90° around the Z-axis. In other words, the Y-axis acceleration sensor element 42y has a fixed comb-tooth electrode fixed to the base 411 and a movable comb-tooth electrode positioned to mesh with the fixed comb-tooth electrode and displaceable in the Y-axis direction relative to the base 411, with the fixed comb-tooth electrode and the movable comb-tooth electrode facing each other in the Y-axis direction. When an acceleration Ay in the Y-axis direction is applied to the Y-axis acceleration sensor element 42y, the movable comb-tooth electrode is displaced in the Y-axis direction, and the capacitance between the fixed comb-tooth electrode and the movable comb-tooth electrode changes according to this displacement. Therefore, this change in capacitance can be taken as an output signal from the connection terminal P3, and the acceleration Ay can be detected based on this output signal. However, the configuration of the Y-axis acceleration sensor element 42y is not particularly limited as long as it can detect the acceleration Ay.

[0031] The Z-axis acceleration sensor element 42z includes a fixed comb-tooth electrode fixed to the base 411 and a movable comb-tooth electrode positioned to mesh with the fixed comb-tooth electrode and displaceable in the Z-axis direction relative to the base 411. When an acceleration Az in the Z-axis direction is applied to the Z-axis acceleration sensor element 42z, the movable comb-tooth electrode is displaced in the Z-axis direction, and the capacitance between the fixed comb-tooth electrode and the movable comb-tooth electrode changes according to this displacement. Therefore, this change in capacitance can be extracted as an output signal from the connection terminal P3, and the acceleration Az can be detected based on this output signal. However, the configuration of the Z-axis acceleration sensor element 42z is not particularly limited as long as it can detect the acceleration Az.

[0032] As shown in Figures 1 to 3, the acceleration sensor 4 with this configuration is bonded to the upper surface of the circuit element 5 via a bonding member (not shown). Each connection terminal P3 is electrically connected to the circuit element 5 via a conductive wire W (bonding wire).

[0033] The acceleration sensor 4 has been described above, but the configuration of the acceleration sensor 4 is not particularly limited. For example, the base 411 and lid 413 may be made of a material other than silicon, such as glass. Also, the package 41 may be divided for each sensor element 42x, 42y, and 42z. In this case, for example, the sensor elements 42x, 42y, and 42z may be stacked in the Z-axis direction. Also, two or more sensor elements selected from the sensor elements 42x, 42y, and 42z may be integrally formed as a single sensor element. In other words, it may be a configuration in which one sensor element can detect two or more of the accelerations Ax, Ay, and Az. Furthermore, the acceleration sensor 4 is not limited to a 3-axis acceleration sensor having three acceleration detection axes, but may also have a configuration with two acceleration detection axes or a configuration with one acceleration detection axis. In this case, it is preferable to have at least a Z-axis acceleration sensor element 42z so that it can detect acceleration Az in the Z-axis direction. This makes it possible to more reliably detect vertical impacts, which are most likely to occur during transportation and are also likely to cause malfunctions. Furthermore, the acceleration sensor 4 may not have a package 41, and the sensor elements 42x, 42y, and 42z may each be exposed in the internal space of the package 7. With such a configuration, further miniaturization of the impact logger 1 can be achieved.

[0034] [Circuit element 5] As shown in Figures 1 to 3, the circuit element 5 is joined to the bottom surface 712 of the recess 711 via a bonding member (not shown). Furthermore, the circuit element 5 is composed of a single chip. By composing the circuit element 5 from a single chip in this way, the circuit element 5 can be miniaturized compared to, for example, the case in the embodiment described later, where the circuit element 5 is composed of multiple chips.

[0035] Furthermore, the circuit element 5 is positioned with its active surface 50, on which multiple connection terminals P4 are formed, facing upwards (towards the positive Z-axis direction), and the acceleration sensor 4 is positioned on the active surface 50. In other words, the circuit element 5 and the acceleration sensor 4 are stacked on the base 71. Some of the multiple connection terminals P4 are electrically connected via wires W to the first internal terminal 741 located on the first stepped surface 713 of the base 71, and the remaining terminals are electrically connected via wires W to the acceleration sensor 4. In the following, the stack of the circuit element 5 and the acceleration sensor 4 will also be referred to as the stacked body H.

[0036] In this way, by arranging the circuit element 5 on the bottom surface 712 and the acceleration sensor 4 on its upper surface, a large area for arranging the circuit element 5 can be secured, allowing for the installation of larger circuit elements 5. As a result, it becomes possible to install circuit elements 5 with higher performance or circuit elements 5 with more functions. In particular, when installing programmable circuit elements 5 that allow users to freely customize functions, the size of the circuit element 5 tends to increase, so the configuration of this embodiment is effective.

[0037] Such a circuit element 5 is, for example, an MCU (Micro Controller Unit) that comprehensively controls each part of the shock logger 1. As shown in Figure 6, the circuit element 5 includes a temperature-compensated oscillation circuit 51 that causes the vibration element 3 to oscillate, a timing circuit 52 that generates time data Dt, a sensor circuit 53 that processes the output signal of the acceleration sensor 4 to determine acceleration Ax, Ay, and Az, a memory circuit 54 that associates the processed data Da, which includes the acceleration Ax, Ay, and Az determined by the sensor circuit 53, with the time data Dt and stores it as event data Di, an interface circuit 55 for communication with the outside, and a control circuit (not shown) that controls each of these circuits 51 to 55.

[0038] The temperature-compensated oscillation circuit 51 includes a temperature sensor circuit 511 that detects the temperature of the vibrating element 3. The temperature sensor circuit 511 is not particularly limited, but for example, it is a circuit equipped with an NTC thermistor, which is a resistor whose resistance value changes according to temperature, and it is a circuit that detects the temperature of the vibrating element 3 by utilizing the change in resistance value. The oscillation circuit 51 is also electrically connected to the vibrating element 3, amplifies the output signal of the vibrating element 3, and feeds back the amplified signal to the vibrating element 3 to cause the vibrating element 3 to oscillate and generate a clock signal CLK. The frequency of the clock signal CLK is, for example, 32.768 kHz. The oscillation circuit 51 also compensates the frequency-temperature characteristics of the clock signal CLK based on the temperature of the vibrating element 3 detected by the temperature sensor circuit 511. In other words, temperature compensation is performed so that the frequency fluctuation of the clock signal CLK is smaller than the frequency-temperature characteristics of the vibrating element 3 itself. With this configuration, the frequency fluctuation of the clock signal CLK due to temperature changes is suppressed, and a highly accurate clock signal CLK can be generated.

[0039] As the oscillation circuit 51, for example, an oscillation circuit such as a Pierce oscillator, an inverter type oscillator, a Colpitts oscillator, or a Hartley oscillator can be used. Furthermore, for temperature compensation, for example, the frequency of the clock signal CLK may be adjusted by adjusting the capacitance of a variable capacitor circuit connected to the oscillation circuit 51, or the frequency of the clock signal CLK generated by the oscillation circuit 51 may be adjusted by a PLL circuit or a direct digital synthesizer circuit.

[0040] The clock signal CLK generated by the oscillation circuit 51 is divided by a frequency divider circuit (not shown) and then input to the timing circuit 52. For example, if the frequency division ratio of the frequency divider circuit is 32, the frequency of the divided clock signal CLK is 1.024 kHz. The timing circuit 52 performs timing based on the clock signal CLK and generates time data Dt. The time data Dt has time digits of seconds, minutes, hours, days, months, and years. In other words, in the shock logger 1, the oscillation circuit 51 generates the clock signal CLK by causing the vibration element 3 to oscillate, and the timing circuit 52 performs timing based on the clock signal CLK and generates time data Dt, thereby configuring a real-time clock (RTC). With this configuration, it is possible to generate time data Dt with high accuracy.

[0041] Furthermore, the sensor circuit 53 controls the drive of the acceleration sensor 4, and determines the acceleration Ax based on the output signal of the X-axis acceleration sensor element 42x, the acceleration Ay based on the output signal of the Y-axis acceleration sensor element 42y, and the acceleration Az based on the output signal of the Z-axis acceleration sensor element 42z. These accelerations Ax, Ay, and Az are then output as processed data Da.

[0042] Furthermore, the memory circuit 54 stores, for example, as shown in Figure 7, the processed data Da (acceleration Ax, Ay, Az) output from the sensor circuit 53 and the temperature data Dtmp detected by the temperature sensor circuit 511 as event data Di, which is associated with the time data Dt generated by the timing circuit 52. In other words, for each measurement cycle, the memory circuit 54 generates and stores event data Di, which associates the current time with the impact that occurred at that time and the temperature at that time. Therefore, the history of impacts received during transport can be easily checked based on the event data Di. In particular, because the event data Di includes temperature data Dtmp, it becomes an impact logger 1 with a large amount of information.

[0043] With this configuration, in addition to identifying the cause of failures based on shocks during transport, it is possible to easily confirm, for example, whether the product (especially products requiring refrigeration or freezing) is always kept at an appropriate temperature range during transport, based on temperature data Dtmp. Furthermore, it is possible to identify failures caused by exposure to excessively high or low temperatures during transport, or failures caused by condensation resulting from rapid temperature changes during transport. Note that the memory circuit 54 does not need to store event data Di for the entire measurement cycle; for example, it may store event data Di only when it detects accelerations Ax, Ay, or Az that exceed a preset threshold. With this configuration, the capacity of the memory circuit 54 can be reduced.

[0044] Furthermore, the interface circuit 55 transmits and receives signals, accepts external inputs (commands), and outputs event data Di stored in the memory circuit 54. The communication method is not particularly limited, but for example, SPI (Serial Peripheral Interface) communication can be used.

[0045] [Battery 6] As shown in Figures 1 to 3, the battery 6 is joined to the bottom surface 712 of the recess 711 via a connecting member (not shown). The battery 6 is also positioned parallel to the circuit element 5 in the X-axis direction. The battery 6 supplies power to the circuit element 5. In other words, the circuit element 5 is driven by power supplied from the battery 6. Therefore, the shock logger 1 can operate without an external power supply. The battery 6 is not particularly limited, but for example, a solid-state battery or a coin-type battery can be used.

[0046] However, the placement of the battery 6 is not particularly limited; for example, it may be placed on the upper surface of the circuit element 5 together with the accelerometer 4, or it may be placed on the upper surface of the accelerometer 4.

[0047] The configuration of the impact logger 1 has been described above. In this impact logger 1, the vibration element 3, support substrate 2, acceleration sensor 4, and circuit element 5 are arranged in line along the Z-axis. Furthermore, in a plan view from the Z-axis direction, the vibration element 3, support substrate 2, acceleration sensor 4, and circuit element 5 overlap each other. With this configuration, the planar spread of the impact logger 1 in the X-axis and Y-axis directions, i.e., the footprint, can be reduced, making the impact logger 1 smaller.

[0048] Furthermore, the natural vibration frequency fr (resonance frequency) of the shock logger 1 is less than 33Hz or greater than 100Hz. In other words, fr < 33Hz or fr > 100Hz. By setting the natural vibration frequency fr within this range, the natural vibration frequency fr of the shock logger 1 can be sufficiently separated from the frequency of the shock applied to the product during transportation. Therefore, it is possible to effectively suppress the shock logger 1 from resonating due to the shock during transportation and detecting an impact greater than the actual impact applied to the product. As a result, it is possible to effectively suppress a decrease in the shock detection accuracy of the shock logger 1.

[0049] The natural vibration frequency fr of the shock logger 1 should be less than 33 Hz or greater than 100 Hz, but it is more preferably less than 25 Hz or greater than 1 kHz, and more preferably less than 20 Hz or greater than 10 kHz. In other words, it is preferable that fr < 25 Hz or fr > 1 kHz, and more preferably fr < 20 Hz or fr > 10 kHz. By setting the natural vibration frequency fr within this range, the natural vibration frequency of the shock logger 1 can be further separated from the frequency of the shock applied to the goods during transport. Therefore, resonance of the shock logger 1 due to shocks during transport can be effectively suppressed, and the decrease in the shock detection accuracy of the shock logger 1 can be more effectively suppressed.

[0050] Generally, goods (objects to be measured for impact) are transported protected from impact by cushioning material. Through the inventor's diligent research, it was found that the duration Tw of impact received by the goods through the cushioning material during transport is approximately 5ms to 14ms. Note that the duration Tw is the time of half a wave of the vibration waveform of the applied impact, as shown in Figure 8. Therefore, an impact with a duration Tw of 5ms corresponds to an impact with a period of 10ms / 1 and a frequency of 100Hz. Similarly, an impact with a duration Tw of 14ms corresponds to an impact with a period of 28ms / 1 and a frequency of 35.71Hz. From this, it can be seen that the frequency of impacts applied to goods during transport is generally between 35.71Hz and 100Hz. In contrast, as mentioned above, the natural vibration frequency fr of impact logger 1 is less than 33Hz or greater than 100Hz, so the natural vibration frequency fr of impact logger 1 does not overlap with the range of 35.71Hz to 100Hz. Therefore, the natural vibration frequency fr of the shock logger 1 can be separated from the frequency of the shock applied to the goods during transport. As a result, as described above, resonance of the shock logger 1 due to shocks during transport can be effectively suppressed, and the decrease in the shock detection accuracy of the shock logger 1 can be effectively suppressed.

[0051] Furthermore, as mentioned above, the above effect becomes more pronounced when the natural vibration frequency fr is less than 25 Hz or greater than 1 kHz, and the above effect becomes even more pronounced when the natural vibration frequency fr is less than 20 Hz or greater than 10 kHz. In other words, the natural vibration frequency fr can be further separated from the frequency of the shock applied to the goods during transport, so that the resonance of the shock logger 1 due to shocks during transport can be suppressed more effectively, and the decrease in the shock detection accuracy of the shock logger 1 can be suppressed more effectively. Note that the action time Tw for a shock with a natural vibration frequency fr of 25 Hz is 20 ms, and the action time Tw for a shock with a natural vibration frequency fr of 1 kHz is 0.5 ms. Also, the action time Tw for a shock with a natural vibration frequency fr of 20 Hz is 25 ms, and the action time Tw for a shock with a natural vibration frequency fr of 10 kHz is 0.05 ms. In other words, by setting the natural vibration frequency fr to less than 25 Hz or greater than 1 kHz, resonance of the shock logger 1 caused by impacts with an action time Tw of 0.5 ms to 20 ms can be effectively suppressed, and by setting the natural vibration frequency fr to less than 20 Hz or greater than 10 kHz, resonance of the shock logger 1 caused by impacts with an action time Tw of 0.05 ms to 25 ms can be effectively suppressed.

[0052] As mentioned above, the package 7 of this embodiment has a base 71 made of various ceramics and a lid 72 made of a metal material such as Kovar. Therefore, a rigid package 7 is obtained, which allows the natural vibration frequency fr of the shock logger 1 to be increased. Thus, the natural vibration frequency fr can be sufficiently increased relative to the frequency of shocks that occur during transport (33Hz to 100Hz). Also, as mentioned above, since the circuit element 5 is made of a single chip, the shock logger 1 can be miniaturized. And by miniaturizing the shock logger 1, the natural vibration frequency fr of the shock logger 1 can be further increased. Thus, the natural vibration frequency fr can be sufficiently increased relative to the frequency of shocks that occur during transport (33Hz to 100Hz).

[0053] The impact logger 1 has been described above. As mentioned above, such an impact logger 1 has a circuit element 5 comprising an acceleration sensor 4, a timing circuit 52 that generates time data Dt, a sensor circuit 53 that processes the output signal of the acceleration sensor 4, and a memory circuit 54 that stores the processed data Da and time data Dt processed by the sensor circuit 53 in association with each other, and a package 7 that houses the acceleration sensor 4 and the circuit element 5, and has a natural vibration frequency fr of less than 33 Hz or greater than 100 Hz. With this configuration, the natural vibration frequency fr of the impact logger 1 can be sufficiently separated from the frequency of the impact applied to the goods (impact measurement target) during transport. Therefore, it is possible to effectively suppress the impact logger 1 from resonating due to impacts during transport and detecting an impact greater than the impact actually applied to the goods. Therefore, it is possible to effectively suppress a decrease in the impact detection accuracy of the impact logger 1.

[0054] Furthermore, as mentioned above, the natural vibration frequency fr is less than 25 Hz or greater than 1 kHz. With this configuration, the natural vibration frequency fr of the shock logger 1 can be further separated from the frequency of the shock applied to the goods (the object to be measured for shock) during transport. Therefore, the decrease in the shock detection accuracy of the shock logger 1 can be suppressed more effectively.

[0055] Furthermore, as mentioned above, the natural vibration frequency fr is less than 20 Hz or greater than 10 kHz. With this configuration, the natural vibration frequency fr of the shock logger 1 can be further separated from the frequency of the shock applied to the goods (the object to be measured for shock) during transport. Therefore, the decrease in the shock detection accuracy of the shock logger 1 can be suppressed even more effectively.

[0056] Furthermore, as mentioned above, the impact logger 1 has a battery 6 that supplies power to the circuit element 5. With this configuration, the impact logger 1 can operate even without an external power supply.

[0057] As mentioned above, the shock logger 1 has a vibrating element 3 housed in the package 7, and the circuit element 5 has an oscillation circuit 51 that causes the vibrating element 3 to oscillate. The oscillation circuit 51 causes the vibrating element 3 to oscillate and generates a clock signal CLK, and the timing circuit 52 performs timing based on the clock signal CLK to generate time data Dt, thereby forming a real-time clock (RTC). With this configuration, it is possible to generate time data Dt with high accuracy.

[0058] Furthermore, as mentioned above, package 7 has a base 71 on which the acceleration sensor 4 and circuit element 5 are arranged. The acceleration sensor 4 and circuit element 5 are arranged on the base 71 in a stacked state. With this configuration, the planar spread of the impact logger 1 in the X-axis and Y-axis directions, that is, the footprint, is suppressed, and the impact logger 1 can be made smaller.

[0059] Furthermore, as mentioned above, the circuit element 5 is placed on the base 71, and the acceleration sensor 4 is placed on the circuit element 5. With this configuration, a larger circuit element 5 can be mounted. Therefore, it is possible to mount a circuit element 5 with higher performance or a circuit element 5 with more functions.

[0060] Furthermore, as mentioned above, the package 7 is bonded to the base 71 and has a lid 72 between it and the base 71 that houses the circuit element 5 and the acceleration sensor 4. This configuration simplifies the package structure.

[0061] Furthermore, as mentioned above, the circuit element 5 is equipped with a temperature sensor circuit 511 that detects temperature, and the memory circuit 54 stores the temperature data Dtmp, processing data Da, and time data Dt detected by the temperature sensor circuit 511 in association with each other. With this configuration, it is also possible to store temperature along with the impact, resulting in an impact logger 1 with a large amount of information.

[0062] <Second Embodiment> Figure 9 is a top view of the impact logger according to the second embodiment. Figure 10 is a cross-sectional view taken along line BB in Figure 9.

[0063] The impact logger 1 of this embodiment is the same as that of the first embodiment described above, except that the configuration of the laminate H is different. In the following description, this embodiment will be described mainly in terms of the differences from the first embodiment described above, and similar matters will not be described. Also, in the figures of this embodiment, the same reference numerals are used for components that are the same as those in the previously described embodiment.

[0064] As shown in Figures 9 and 10, in the impact logger 1 of this embodiment, the stacking order of the laminate H is reversed compared to the first embodiment, with the acceleration sensor 4 placed on the bottom surface 712 of the recess 711 and the circuit element 5 placed on the upper surface of the acceleration sensor 4. In other words, the acceleration sensor 4 is placed on the base 71, and the circuit element 5 is placed on the acceleration sensor 4. By placing the acceleration sensor 4 below the circuit element 5 in this way, the available area for the acceleration sensor 4 can be increased, and a larger acceleration sensor 4 can be mounted. Therefore, for example, compared to the first embodiment described above, the capacitance formed between the fixed comb-tooth electrodes and the movable comb-tooth electrodes of each sensor element 42x, 42y, and 42z can be increased, and the accelerations Ax, Ay, and Az can be detected with greater accuracy.

[0065] As described above, in the impact logger 1 of this embodiment, an acceleration sensor 4 is placed on the base 71, and a circuit element 5 is placed on the acceleration sensor 4. With this configuration, a larger acceleration sensor 4 can be mounted, and impact (acceleration Ax, Ay, Az) can be detected with greater accuracy.

[0066] This second embodiment can also achieve the same effects as the first embodiment described above.

[0067] <Third Embodiment> Figure 11 is a cross-sectional view of the impact logger according to the third embodiment.

[0068] The impact logger 1 of this embodiment is the same as that of the first embodiment described above, except for the configuration of the package 7 and the arrangement of the battery 6. In the following description, this embodiment will be described mainly for the differences from the first embodiment described above, and similar matters will not be described. Also, in the figures of this embodiment, the same reference numerals are used for components that are the same as those in the previously described embodiment.

[0069] As shown in Figure 11, in the impact logger 1 of this embodiment, the base 71 of the package 7 has a recess 719 opening on the bottom surface in addition to a recess 711 opening on the top surface. The battery 6 is housed in the recess 719 and is positioned on the bottom surface of the recess 719. Furthermore, the battery 6 overlaps with the circuit element 5 in a plan view from the Z-axis direction. By arranging the battery 6 to overlap with the circuit element 5 in this way, for example, the planar expansion of the impact logger 1 in the X-axis and Y-axis directions can be further suppressed compared to the first embodiment described above, thereby enabling further miniaturization of the impact logger 1. In addition, with this configuration, the battery 6 is exposed to the outside of the package 7, making it easy to replace the battery 6. Therefore, long-term continuous use and reuse of the impact logger 1 by replacing the battery becomes easier.

[0070] As described above, the impact logger 1 of this embodiment has a battery 6 that supplies power to the circuit element 5. The battery 6 is exposed to the outside of the package 7. With this configuration, the battery 6 can be easily replaced, and the impact logger 1 can be used and reused for a long period of time by replacing the battery.

[0071] This third embodiment can also achieve the same effects as the first embodiment described above.

[0072] <Fourth Embodiment> Figure 12 is a top view of the impact logger according to the fourth embodiment. Figure 13 is a cross-sectional view taken along line CC in Figure 12. For the sake of clarity, the support substrate 2 and the vibration element 3 are not shown in Figure 12.

[0073] The impact logger 1 of this embodiment is the same as that of the first embodiment described above, except for the difference in the mounting method of the circuit element 5. In the following description, this embodiment will be described mainly for the differences from the first embodiment described above, and similar matters will not be described. Also, in the figures of this embodiment, the same reference numerals are used for components that are the same as those in the previously described embodiment.

[0074] In the first embodiment described above, the circuit element 5 was bonded to the bottom surface 712 with its active surface 50 facing upwards. However, in this embodiment, as shown in Figures 12 and 13, the circuit element 5 is mounted on the bottom surface 712 using FCB (flip-chip bonding) with its active surface 50 facing downwards. Multiple first internal terminals 741 are arranged on the bottom surface 712, and each connection terminal P4 of the circuit element 5 is electrically connected to the corresponding first internal terminal 741 via a conductive bonding member B3 such as a gold ball. With this configuration, the first stepped surface 713 can be omitted, thus enabling miniaturization of the impact logger 1.

[0075] This fourth embodiment can also achieve the same effects as the first embodiment described above.

[0076] <Fifth Embodiment> Figure 14 is a top view of the impact logger according to the fifth embodiment.

[0077] The impact logger 1 of this embodiment is the same as that of the first embodiment described above, except that the arrangement of each part within the package 7 is different. In the following description, this embodiment will be described mainly in terms of the differences from the first embodiment described above, and similar matters will not be described. Also, in the figures of this embodiment, the same reference numerals are used for components that are the same as those in the previously described embodiment.

[0078] As shown in Figure 14, the impact logger 1 of this embodiment omits the support substrate 2, and the vibration element 3, acceleration sensor 4, circuit element 5, and battery 6 are each arranged on the bottom surface 712 of the recess 711. In other words, in the impact logger 1 of this embodiment, the vibration element 3, acceleration sensor 4, circuit element 5, and battery 6 are arranged planarly without overlapping each other. With this configuration, for example, compared to the first embodiment described above, the spread in the XY plane direction is increased, while the thickness in the Z axis direction can be kept small. Therefore, the impact logger 1 is suitable for environments where thinness is prioritized over a small footprint. In this embodiment, the second stepped surface 714 is omitted from the base 71, and the second internal terminal 742 for the vibration element 3 is arranged on the bottom surface 712 of the recess 711.

[0079] This fifth embodiment can also achieve the same effects as the first embodiment described above. However, the configuration of the impact logger 1 is not particularly limited. For example, in combination with the embodiments described above, the circuit element 5 and the acceleration sensor 4 may be stacked to form a laminate H. Furthermore, the base 71 may have a recess 719, and the battery 6 may be placed on the bottom surface of the recess 719.

[0080] <Sixth Embodiment> Figure 15 is a top view of the impact logger according to the sixth embodiment. For the sake of clarity, Figure 15 omits the illustration of components that are not necessary for the explanation, such as the connection terminal P3 and wire W.

[0081] The impact logger 1 of this embodiment is the same as that of the fifth embodiment described above, except that the configuration of the circuit element 5 is different. In the following description, this embodiment will be described mainly in terms of the differences from the first embodiment described above, and similar matters will not be described. Also, in the figures of this embodiment, the same reference numerals are used for components that are the same as those in the previously described embodiments.

[0082] In the fifth embodiment described above, the circuit element 5 was composed of a single chip, but in this embodiment, the circuit element 5 is composed of multiple chips. Specifically, as shown in Figure 15, the circuit element 5 is divided into a first circuit element 5A on which an oscillation circuit 51 and a control circuit (not shown) are formed, a second circuit element 5B on which a timing circuit 52 is formed, a third circuit element 5C on which a sensor circuit 53 is formed, a fourth circuit element 5D on which a memory circuit 54 is formed, and a fifth circuit element 5E on which an interface circuit 55 is formed. By composing the circuit element 5 with multiple chips in this way, the degree of freedom in arranging the circuit element 5 is increased.

[0083] This sixth embodiment can also achieve the same effects as the fifth embodiment described above. However, the configuration of the shock logger 1 is not particularly limited, and for example, the circuit element 5 may be divided into two to four or six or more chips. Also, one or more circuits can be arbitrarily combined for each circuit element.

[0084] <Seventh Embodiment> Figure 16 is a cross-sectional view of the impact logger according to the seventh embodiment.

[0085] The impact logger 1 of this embodiment is the same as that of the fifth embodiment described above, except that the real-time clock and the configuration of the package 7 are different. In the following description, this embodiment will be described mainly in terms of the differences from the first embodiment described above, and similar matters will not be described. Also, in the figures of this embodiment, the same reference numerals are used for components that are the same as those in the previously described embodiments.

[0086] In the impact logger 1 of this embodiment, the package 7 has a plate-shaped base 78 and a molded portion 79 that molds and seals each part placed on the base 78. With this configuration, the package 7 is simple.

[0087] The base 78 is plate-shaped and is made of, for example, ceramics, FPC (flexible printed circuit board), etc. The vibrator 8, acceleration sensor 4, circuit element 5, and battery 6 are arranged on the upper surface of the base 78, respectively. Here, the vibrator 8 is a real-time clock (RTC) and has a package 80, a vibrating element 3 housed in the package 80, and a circuit element 81. The circuit element 81 has an oscillation circuit 51 and a timing circuit 52 formed thereon. The circuit element 5 has the remaining sensor circuit 53, memory circuit 54, interface circuit 55, control circuit (not shown), etc. If the vibrating element 3 is exposed inside the package 7 as in the first embodiment described above, the vibrating element 3 cannot be molded, but as in this embodiment, by housing the vibrating element 3 in the package 80, it becomes possible to mold it.

[0088] The molded portion 79 encloses the oscillator 8, acceleration sensor 4, and circuit element 5, protecting them from moisture, dust, impact, etc. The molding material constituting the molded portion 79 is not particularly limited, and for example, a thermosetting epoxy resin or other curing resin material can be used. Furthermore, the molded portion 79 can be formed by, for example, a transfer molding method.

[0089] With this configuration, since package 7 has a solid structure, the natural vibration frequency fr of the shock logger 1 can be sufficiently increased relative to the frequency of shocks that occur during transport (33Hz to 100Hz). Therefore, the shock logger 1 can more effectively suppress resonance with shocks during transport and detect shocks with even greater accuracy.

[0090] As described above, in the impact logger 1 of this embodiment, the package 7 has a molded portion 79 that seals the circuit element 5 and the acceleration sensor 4. With this configuration, the package 7 is simple. In addition, because the package 7 has a solid structure, the natural vibration frequency fr of the impact logger 1 can be increased. Therefore, resonance with impacts during transportation can be suppressed more effectively, and impacts can be detected with even higher accuracy.

[0091] This seventh embodiment can also achieve the same effects as the fifth embodiment described above.

[0092] The impact logger of the present invention has been described above based on the illustrated embodiment, but the present invention is not limited thereto. The configuration of each part can be replaced with any configuration having a similar function. In addition, any other configuration may be added to the present invention. For example, if an external power supply is possible, the battery 6 may be omitted. [Explanation of Symbols]

[0093] 1…Impact logger, 2…Support board, 21…Wiring, 22…Wiring, 3…Vibration element, 30…Base, 31…Vibration arm, 32…Vibration arm, 33…Support arm, 34…Support arm, 4…Accelerometer, 41…Package, 411…Base, 413…Lid, 42x…X-axis accelerometer element, 42y…Y-axis accelerometer element, 42z…Z-axis accelerometer element, 5…Circuit element, 5A…First circuit element, 5B…Second circuit element, 5C…Third circuit element, 5D…Fourth circuit element, 5E…Fifth circuit element, 50…Active surface, 51…Oscillation circuit, 511…Temperature sensor circuit, 52…Timekeeping circuit, 53…Sensor circuit, 54…Memory circuit, 55…Interface circuit, 6…Battery, 7…Package, 71…Base, 711…Recess, 7 12...Bottom surface, 713...First step surface, 714...Second step surface, 719...Recess, 72...Lid, 73...Seam ring, 741...First internal terminal, 742...Second internal terminal, 743...External terminal, 78...Base, 79...Molded part, 8...Vibrator, 80...Package, 81...Circuit element, Ax...Acceleration, Ay...Acceleration, Az...Acceleration, B1...Bonding member, B2...Bonding member, B3...Bonding member, CLK...Clock signal, Da...Processing data, Di...Event data, Dt...Time data, Dtmp...Temperature data, E1...First excitation electrode, E2...Second excitation electrode, H...Laminate, P1...First connection terminal, P2...Second connection terminal, P3...Connection terminal, P4...Connection terminal, RTC...Real-time clock, W...Operating time, W...Wire

Claims

1. Accelerometer and A circuit element comprising: a timing circuit that generates time data; a sensor circuit that processes the output signal of the acceleration sensor; and a memory circuit that stores the processed data processed by the sensor circuit and the time data in association; The package comprises the acceleration sensor and the circuit element, An impact logger characterized by having a natural vibration frequency of less than 33 Hz or more than 100 Hz.

2. The impact logger according to claim 1, wherein the natural vibration frequency is less than 25 Hz or greater than 1 kHz.

3. The impact logger according to claim 2, wherein the natural vibration frequency is less than 20 Hz or greater than 10 kHz.

4. The shock logger according to claim 1, further comprising a battery that supplies power to the circuit element.

5. The impact logger according to claim 4, wherein the battery is exposed to the outside of the package.

6. The package has a vibrating element housed within it, The circuit element has an oscillation circuit that causes the vibration element to oscillate. The shock logger according to claim 1, wherein a real-time clock is configured by the oscillation circuit causing the vibration element to oscillate and generate a clock signal, and the timing circuit performing timing based on the clock signal to generate the time data.

7. The package has a base on which the acceleration sensor and the circuit elements are arranged. The impact logger according to claim 1, wherein the acceleration sensor and the circuit elements are arranged on the base in a stacked state.

8. The circuit element is arranged on the base, The impact logger according to claim 7, wherein the acceleration sensor is arranged on the circuit element.

9. The acceleration sensor is placed on the base, The impact logger according to claim 7, wherein the circuit element is arranged on the acceleration sensor.

10. The impact logger according to any one of claims 7 to 9, wherein the package is bonded to the base and has a lid between it and the base that houses the circuit element and the acceleration sensor.

11. The impact logger according to any one of claims 7 to 9, wherein the package has a molded portion that seals the circuit element and the acceleration sensor.

12. The circuit element includes a temperature sensor circuit for detecting temperature, The shock logger according to claim 1, wherein the memory circuit stores the temperature data detected by the temperature sensor circuit, the processing data, and the time data in association.

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