Sensor unit, vehicle positioning device, and vehicle

A sensor unit includes a circuit board including, on a first surface, a plurality of electrode pads to which a plurality of mounting terminals of an inertial sensor are respectively attached via connecting members. The first surface of the circuit board includes an insulating layer provided on the outer side of the plurality of electrode pads in a plan view, includes, in a portion overlapping a center region further on the inner side than the mounting terminals of the inertial sensor in the plan view, a first region where the insulating layer is not provided, and includes, from the first region to the outer side of the inertial sensor in the plan view, a second region where the insulating layer is not provided.

BACKGROUND

1. Technical Field

The present invention relates to a sensor unit, a vehicle positioning device, a portable electronic device, an electronic device, a vehicle, and a display device.

2. Related Art

A known sensor unit includes inertial sensors such as an acceleration sensor and an angular velocity sensor mounted on a substrate housed in a case. The sensor unit detects inertia based on a predetermined detection axis. For example, JP-A-2017-20829 describes an inertial measurement unit (IMU) in which a connector, an angular velocity sensor, an acceleration sensor, and the like are mounted on a substrate, the surface of which is protected by resist.

However, in the inertial measurement unit (the sensor unit) described in JP-A-2017-20829, foreign matters sometimes remain between the inertial sensor (the acceleration or the like) that is surface-mounted on the substrate and the substrate. As a consequence, temperature hysteresis is likely to occur in a bias signal (a detection output signal) because of the remaining foreign matters.

SUMMARY

A sensor unit according to an aspect of the invention includes: an inertial sensor; a circuit board including, on a first surface, a plurality of electrode pads to which a plurality of mounting terminals of the inertial sensor are respectively attached via connecting members; and a case, on an inside of which the circuit board is housed. The first surface of the circuit board includes an insulating layer provided on an outer side of the plurality of electrode pads in a plan view, includes, in a portion overlapping a center region further on an inner side than the mounting terminals of the inertial sensor in the plan view, a first region where the insulating layer is not provided, and includes, from the first region to an outer side of the inertial sensor in the plan view, a second region where the insulating layer is not provided.

In the sensor unit, it is preferable that recessed sections are provided in the first region and the second region of the first surface of the circuit board.

In the sensor unit, it is preferable that, in the circuit board, a through-hole piercing through the circuit board is provided in the first region.

In the sensor unit, it is preferable that the second region is provided between the electrode pads adjacent to each other.

In the sensor unit, it is preferable that a peripheral projecting section or an unconnected projecting section is provided between a center of the inertial sensor and the electrode pads in the plan view.

In the sensor unit, it is preferable that the peripheral projecting section or the unconnected projecting section is closer to the electrode pads side than the center side of the inertial sensor.

In the sensor unit, it is preferable that the peripheral projecting section or the unconnected projecting section is an insulating layer.

In the sensor unit, it is preferable that the inertial sensor has a square shape in the plan view, and the plurality of mounting terminals are disposed on an opposed pair of sides of the square shape.

In the sensor unit, it is preferable that the inertial sensor is an acceleration sensor.

A vehicle positioning device according to another aspect of the invention includes: the sensor unit; a receiving section configured to receive a satellite signal superimposed with position information from a positioning satellite; an acquiring section configured to acquire the position information of the receiving section on the basis of the received satellite signal; a computing section configured to compute a posture of a vehicle on the basis of inertial data output from the sensor unit; and a calculating section configured to calculate a position of the vehicle by correcting the position information on the basis of the computed posture.

A portable electronic device according to still another aspect of the invention includes: the sensor unit; a case in which the sensor unit is housed; a processing section housed in the case and configured to process output data from the sensor unit; a display section housed in the case; and a light transmissive cover closing an opening section of the case.

In the portable electronic device, it is preferable that the portable electronic device includes a satellite positioning system and measures a moving distance and a moving track of a user.

An electronic device according to still another aspect of the invention includes: the sensor unit; and a control section configured to perform control on the basis of a detection signal output from the sensor unit.

A vehicle according to still another aspect of the invention includes: the sensor unit; and a control section configured to perform control on the basis of a detection signal output from the sensor unit.

In the vehicle, it is preferable that the vehicle includes at least any one system of an engine system, a brake system, and a keyless entry system, and the control section controls the system on the basis of the detection signal.

A vehicle according to still another aspect of the invention includes: the sensor unit; and a control section configured to control at least any one of acceleration, braking, and steering on the basis of a detection signal detected by the sensor unit. Whether automatic driving is carried out or not is switched according to a change of the detection signal output from the sensor unit.

A display device according to still another aspect of the invention includes: a display section worn on a head of a user and configured to irradiate image light on eyes of the user; and the sensor unit. The sensor unit is located further on one side than a center of the head in a mounted state of the display device.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

An embodiment is explained below. The embodiment explained below does not unduly limit the scope of the invention described in the appended claims. Not all of components explained in the embodiment are essential constituent elements of the invention.

Sensor Unit

Overview of a Sensor Unit

First, an overview of a sensor unit is explained with reference toFIGS. 1 and 2.FIG. 1is a perspective view showing a state in which a sensor unit according to the embodiment is fixed to a mounting surface.FIG. 2is a perspective view showing the overview of the sensor unit viewed from the mounting surface side inFIG. 1.

As shown inFIG. 1, a sensor unit100is an inertial measurement unit (hereinafter, IMU) that detects postures and behaviors (inertial momentums) of vehicles (devices on which the sensor unit100is mounted) such as an automobile, an agricultural machine, a construction machine, a robot, and a drone. The sensor unit100functions as a so-called six-axis motion sensor including a three-axis acceleration sensor and a three-axis angular velocity sensor functioning as inertial sensors.

The sensor unit100is a rectangular parallelepiped that is substantially square in a planar shape. The length of one side of the square is approximately 3 cm and the thickness of the sensor unit100is approximately 1 cm. Screw holes2functioning as fixed sections are formed near vertexes in two places located in a diagonal direction of the square. The sensor unit100is used in a state in which two screws70are inserted through the screw holes2in the two places to fix the sensor unit100to a mounting surface71of a body (a device) on which the sensor unit100is mounted such as an automobile. The size described above is an example. The sensor unit100can be miniaturized to sizes mountable on, for example, an HMD (a head mounted display or a smartglass), a smartphone, and a digital camera according to selection of components and a design change. An opening on the opposite side of the mounting surface71of the sensor unit100is covered by a lid8.

The sensor unit100adopts a characteristic package configuration for reducing noise vibration such as engine vibration of an automobile transmitted from the mounting surface71. This configuration realizes reliability and stability of detection accuracy higher than those of the sensor unit in the past.

This characteristic package configuration is explained in detail below. This configuration is not limited to the IMU including the six-axis motion sensor and is applicable to any unit or device including an inertial sensor.

As shown inFIG. 2, an opening section21is formed on the surface of the sensor unit100viewed from the mounting surface side. A plug-type (male) connector16is disposed on the inside (the inner side) of the opening section21. The connector16has a plurality of pins. The plurality of pins are disposed to extend in the lateral direction when viewed from a direction right opposed toFIG. 2. A socket-type (female) connector (not shown inFIG. 2) is connected to the connector16from the device on which the sensor unit100is mounted. A driving voltage of the sensor unit100and an electric signal such as detection data are transmitted and received between the connectors.

In the following explanation, the extending direction of the plurality of pins is represented as an X-axis direction. In other words, in the square shape of the sensor unit100, an extending direction of a side that is the lateral direction when viewed from the direction right opposed toFIG. 2is representing as the X-axis direction. An extending direction of a side in a direction orthogonal to the X-axis direction in the square shape is represented as a Y-axis direction. The thickness direction of the sensor unit100is represented as a Z-axis direction.

Configuration of the Sensor Unit

The configuration of the sensor unit is explained with reference toFIG. 3in addition toFIGS. 1 and 2.FIG. 3is an exploded perspective view of the sensor unit when viewed from the same direction as a direction as a direction in which the sensor unit is viewed inFIG. 2.

As shown inFIG. 3, the sensor unit100is configured from an outer case1, a joining member (a buffering member)10, a circuit board15, an inner case20, and the like. In other words, the circuit board15and the inner case20are fit (inserted) in this order on an inside3of the outer case1via the joining member (the buffering member)10. A module configured from the circuit board15and the inner case20functioning as a case in which the circuit board15is housed is referred to as sensor module25. To facilitate explanation, the parts are referred to as the outer case and the inner case. However, the parts may also be referred to as the first case and the second case.

The outer case1is a pedestal obtained by cutting aluminum into a box shape. The material of the outer case1is not limited to aluminum. Another kind of metal such as zinc or stainless steel, resin, or a composite material of metal and resin may be used. Like the overall shape of the sensor unit100, the external shape of the outer case1is a rectangular parallelepiped that is substantially square in a planar shape. The screw holes2are respectively formed near vertexes in two places located in a diagonal direction of the square. Means for fixing the outer case1is not limited to the screw holes2. For example, cutouts that can be screwed by screws may be formed (cutouts may be formed in outer case1corner portions of the screw holes2) to screw the outer case1. Alternatively, flanges (ears) may be formed on side surface of the outer case1and screwed. However, when the outer case1is screwed using the cutout holes in the former case as fixed sections, the screws deviate from the cutouts to be slant in the screwing if the cutouts of the cutout holes are opened wider than a screw diameter. The fixing of the screwing is likely to easily come off. The cutout hole portions of the outer case are likely to be deformed and shaved by the deviating screws. Therefore, when the cutout holes are provided as the fixed sections, it is desirable to form the cutouts of the cutout holes to be smaller than the diameter of screw heads that form a seating surface.

The external shape of the outer case1is a rectangular parallelepiped and is a lidless box shape. The inside3(the inner side) of the outer case1is formed as an internal space (a container) surrounded by a bottom wall5and a sidewall4. In other words, the outer case1is formed in a box shape having one surface opposed to the bottom wall5as an opening surface. The sensor module25is housed to cover most of an opening section of the opening surface (to close the opening section). The sensor module25is exposed from the opening section (seeFIG. 2). The opening surface opposed to the bottom wall5is flush with an upper surface7of the outer case1. A planar shape of the inside3of the outer case1is a hexagon formed by chamfering corners of the two vertex portions of the square. The chamfered two vertex portions correspond to the positions of the screw holes2. In a sectional shape (in the thickness direction) of the inside3, a first joining surface6functioning as a bottom wall higher than the center by one stage is formed in the peripheral edge portion on the inside3, that is, in the internal space. That is, the first joining surface6is a part of the bottom wall5, is a step-like part of one stage formed in a ring shape to planarly surround the center of the bottom wall5, and is a surface, the distance to which from the opening surface (flush with the upper surface7) is smaller than the distance to the bottom wall5.

The example is explained above in which the external shape of the outer case1is the rectangular parallelepiped, the planar shape of which is substantially square, and is the lidless box shape. However, the external shape of the outer case1is not limited to this. The planar shape of the external shape of the outer case1may be a polygon such as a hexagon or an octagon. Corners of vertex portions of the polygon may be chamfered or sides of the polygon may be curved lines. The planar shape of the inside3(the inner side) of the outer case1is not limited to the hexagon and may be a quadrate (a quadrangle) such as a square or another polygonal shape such as an octagon. The external shape of the outer case1and the planar shape of the inside3may be similar shapes or may not be similar shapes.

The inner case20is a member that supports the circuit board15. The inner case20is formed in a shape fit in the inside3of the outer case1. In detail, planarly, the inner case20is a hexagon obtained by chamfering corners of two vertex portions of a square. In the inner case20, an opening section21, which is a rectangular through-hole, is formed on a lower surface27of the hexagon in the plan view. A recessed section28provided on a surface on a side that supports the circuit board15is formed. The chamfered two vertex portions correspond to the positions of the screw holes2of the outer case1. The thickness (in the Z-axis direction) of the inner case20is smaller than the height from the upper surface7of the outer case1to the first joining surface6. In a preferred example, the inner case20is also formed by cutting aluminum. However, as in the outer case1, another material may be used.

Guide pins for positioning the circuit board15and a supporting surface (both of which are not shown inFIG. 3) are formed on the rear surface (the surface on the outer case1side) of the inner case20. The circuit board15is set (positioned and mounted) on the guide pins and the supporting surface and bonded to the rear surface of the inner case20. Details of the circuit board15are explained below. The peripheral edge portion of the rear surface of the inner case20is formed as a second joining surface22formed by a ring-like plane. The second joining surface22planarly has a shape substantially the same as the first joining surface6of the outer case1. When the inner case20is set in the outer case1, the two surfaces are opposed to each other in a state in which the joining member10is held between the surfaces. The structures of the outer case1and the inner case20are examples and are not limited.

Configuration of the Circuit Unit

The configuration of the circuit unit in which the inertial sensor is mounted on the circuit board15is explained with reference toFIG. 4.FIG. 4is an exterior perspective view showing a schematic configuration of the circuit unit.

The connector16, an angular velocity sensor17z, an acceleration sensor18, and the like are mounted on a first surface (the surface15fon the inner case20side, seeFIG. 7A) of the circuit board15configuring the circuit unit. The connector16is a plug-type (male) connector. The connector16includes connection terminals in two rows disposed at equal pitches in the X-axis direction. The connection terminals suitably include ten pins in each row, that is, twenty pins in total. However, the number of terminals may be changed as desired according to a design specification.

The angular velocity sensor17zis a gyro sensor that detects one-axis angular velocity in the Z-axis direction. As a suitable example, quartz is used as a vibrator. A vibration gyro sensor that detects angular velocity from a Coriolis force applied by a vibrating object is used as the angular velocity sensor17z. The gyro sensor is not limited to the vibration gyro sensor and can be any sensor capable of detecting angular velocity. For example, a sensor in which ceramic or silicon is used as the vibrator may be used as the gyro sensor.

An angular velocity sensor17xthat detects one-axis angular velocity in the X-axis direction is mounted on the side surface in the X-axis direction of the circuit board15such that a mounting surface is orthogonal to the X axis. Similarly, an angular velocity sensor17ythat detects one-axis angular velocity in the Y-axis direction is mounted on the side surface in the Y-axis direction of the circuit board15such that a mounting surface is orthogonal to the Y axis. The circuit unit is not limited to the configuration including the three angular velocity sensors for the respective axes. The circuit unit may include a sensor capable of detecting three-axis angular velocities. For example, like the acceleration sensor18explained below, a sensor device capable of detecting three-axis angular velocities with one device (package) may be used.

As the acceleration sensor18functioning as an inertial sensor, a capacitance-type acceleration sensor, which is obtained by machining a silicon substrate with a MEMS technique, capable of detecting accelerations in three directions (three axes) of the X axis, the Y axis, and the Z axis with one device is used. The acceleration sensor18is not limited to this sensor and can be any sensor capable of detecting acceleration. For example, the acceleration sensor18may be a piezo-resistive acceleration sensor or a thermosensitive acceleration sensor. Like the angular velocity sensor, one acceleration sensor may be provided for each of the axes.

A control IC19is mounted on the rear surface (the surface on the outer case1side) of the circuit board15. The control IC19is an MCU (Micro Controller Unit). The control IC19incorporates a storing section including a nonvolatile memory, an A/D converter, and the like and controls the sections of the sensor unit100. The storing section has stored therein a computer program that specifies order and content for detecting acceleration and angular velocity, a computer program for digitizing detection data and incorporating the detection data in packet data, incidental data, and the like. Besides, a plurality of electronic components are mounted on the circuit board15.

Configuration of X-axis and Y-axis acceleration sensors

The configuration of an X-axis acceleration sensor and a Y-axis acceleration sensor mounted on the acceleration sensor18as inertial sensors is explained with reference toFIG. 5.FIG. 5is a plan view for explaining the configuration of the X-axis acceleration sensor.

An X-axis acceleration sensor101shown inFIG. 5detects acceleration Ax in the X-axis direction. Such an X-axis acceleration sensor101includes a base section102and an element section103provided in the base section102and configured to detect the acceleration Ax (a physical quantity) in the X-axis direction. The element section103includes a fixed electrode section104attached to the base section102, a movable section152displaceable in the X-axis direction (a first direction, which is a detection axis direction of the physical quantity) with respect to the base section102via a spring section153, and a movable electrode section106provided in the movable section152. The fixed electrode section104includes a first fixed electrode section141and a second fixed electrode section142disposed side by side along the Y-axis direction (a second direction, which is a direction crossing (in this embodiment, orthogonal to) the detection axis). The first fixed electrode section141includes a first trunk section411and a plurality of first fixed electrode fingers412provided on both sides in the Y-axis direction (the second direction) of the first trunk section411and having a longitudinal direction along the second direction. The second fixed electrode section142includes a second trunk section421and a plurality of second fixed electrode fingers422provided on both sides in the Y-axis direction (the second direction) from the second trunk section421and having a longitudinal direction along the second direction. The movable electrode section106includes a first movable electrode section161and a second movable electrode section162disposed side by side along the Y-axis direction (the second direction). At least a part of the first movable electrode section161includes a plurality of first movable electrode fingers611located on both sides in the Y-axis direction (the second direction) of the first trunk section411, having a longitudinal direction along the second direction, and opposed to the first fixed electrode fingers412in the X-axis direction (the first direction). At least a part of the second movable electrode section162includes a plurality of second movable electrode fingers621located on both sides in the Y-axis direction (the second direction) of the second trunk section421, having a longitudinal direction along the second direction, and opposed to the second fixed electrode fingers422in the X-axis direction (the first direction). By adopting such a configuration, it is possible to respectively reduce the first fixed electrode fingers412, the second fixed electrode fingers422, the first movable electrode fingers611, and the second movable electrode fingers621in length while keeping capacitance between the first movable electrode fingers611and the first fixed electrode fingers412and capacitance between the second movable electrode fingers621and the second fixed electrode fingers422sufficiently large. Therefore, the first fixed electrode fingers412, the second fixed electrode fingers422, the first movable electrode fingers611, and the second movable electrode fingers621are hardly broken. The X-axis acceleration sensor101having excellent shock resistance is obtained.

Although not shown inFIG. 5, by disposing the X-axis acceleration sensor101shown inFIG. 5and explained in the direction in which the base section102and the element section103provided in the base section102are disposed side by side along the Y-axis direction, the X-direction acceleration sensor101can function as a Y-axis acceleration sensor and detect acceleration in the Y-axis direction.

Acceleration Sensor Element that Detects Acceleration in the Z-Axis Direction

FIG. 6is a plan view for explaining the configuration of a Z-axis acceleration sensor. The configuration of the Z-axis acceleration sensor mounted on the acceleration sensor18functioning as the inertial sensor is explained with reference toFIG. 6.

A Z-axis acceleration sensor201includes a movable body220. Further, the movable body220includes a first movable section220aand a second movable section220b. The movable body220includes, in the plan view, with a support axis Q as a boundary, a first movable section220aon one side in a direction orthogonal to the support axis Q and a second movable section220bon the other side in the orthogonal direction. The movable body220further includes a third beam section243and a fourth beam section244configured to connect the first movable section220aand the second movable section220b, a first beam section241configured to couple first and second fixed sections232and234and the third beam section243, a second beam section242configured to couple the first and second fixed sections232and234and the fourth beam section244, and an opening section226disposed between the third beam section243and the fourth beam section244in the plan view. The first movable section220ais located on one side of the support axis Q (in an example shown inFIG. 6, a −X-axis direction) in the plan view (when viewed from the Z-axis direction side). The second movable section220bis located on the other side of the support axis Q (in the example shown inFIG. 6, on a +X-axis direction side).

When acceleration (e.g., gravitational acceleration) in the vertical direction is applied to the movable body220, rotational moments (moments of force) are respectively generated in the first movable section220aand the second movable section220b. When the rotational moment (e.g., a counterclockwise rotational moment) of the first movable section220aand the rotational moment (e.g., a clockwise rotational moment) of the second movable section220bare balanced, a change does not occur in a tilt of the movable body220and acceleration cannot be detected. Therefore, the movable body220is designed such that the rotational moment of the first movable section220aand the rotational moment of the second movable section220bare not balanced and a predetermined tilt occurs in the movable body220when the acceleration in the vertical direction is applied.

In the Z-axis acceleration sensor201, the support axis Q is disposed in a position deviating from the center (the center of gravity) of the movable body220(distances from the support axis Q to the distal ends of the first movable section220aand the second movable section220bare set different from each other), whereby the mass of the first movable section220aand the mass of the second movable section220bare different from each other. That is, in the movable body220, the mass on one side (the first movable section220a) and the mass on the other side (the second movable section220b) are different with the support axis Q as a boundary. In the example shown inFIG. 6, the distance from the support axis Q to an end face223of the first movable section220ais larger than the distance from the support axis Q to an end face224of the second movable section220b. The thickness of the first movable section220aand the thickness of the second movable section220bare equal. Therefore, the mass of the first movable section220ais larger than the mass of the second movable section220b.

In this way, the mass of the first movable section220aand the mass of the second movable section220bare different from each other. Consequently, when the acceleration in the vertical direction is applied, it is possible to prevent the rotational moment of the first movable section220aand the rotational moment of the second movable section220bfrom being balanced. Therefore, when the acceleration in the vertical direction is applied, it is possible to cause the predetermined tilt in the movable body220.

Although not shown inFIG. 6, the mass of the first movable section220aand the mass of the second movable section220bmay be set different from each other by disposing the support axis Q in the center of the movable body220and setting the thickness of the first movable section220aand the thickness of the second movable section220bdifferent from each other. Even in such a case, when the acceleration in the vertical direction is applied, it is possible to cause the predetermined tilt in the movable body220.

The movable body220is provided to be separated from a substrate210. The movable body220is provided above a recessed section211. A gap is provided between the movable body220and the substrate210. Consequently, the movable body220can swing.

The movable body220includes a first movable electrode221and a second movable electrode222provided with the support axis Q as a boundary. The first movable electrode221is provided in the first movable section220a. The second movable electrode222is provided in the second movable section220b.

The first movable electrode221is a portion overlapping the first fixed electrode250in the plan view in the movable body220. The first movable electrode221forms capacitance C1between the first movable electrode221and the first fixed electrode250. That is, the capacitance C1is formed by the first movable electrode221and the first fixed electrode250.

The second movable electrode222is a portion overlapping the second fixe electrode252in the plan view in the movable body220. The second movable electrode222forms capacitance C2between the second movable electrode222and the second fixed electrode252. That is, the capacitance C2is formed by the second movable electrode222and the second fixed electrode252. In the Z-axis acceleration sensor201, the movable body220is made of a conductive material (silicon doped with impurities), whereby the first movable electrode221and the second movable electrode222are provided. That is, the first movable section220afunctions as the first movable electrode221. The second movable section220bfunctions as the second movable electrode222.

The capacitance C1and the capacitance C2are set to be equal to each other, for example, in a state in which the movable body220is horizontal. The positions of the first movable electrode221and the second movable electrode222change according to a movement of the movable body220. The capacitance C1and the capacitance C2change according to the positions of the first movable electrode221and the second movable electrode222. Predetermined potential is applied to the movable body220via a supporting section230.

A plurality of through-holes225piecing through the movable body220are formed in the movable body220. Consequently, the influence of the air (the resistance of the air) at the time when the movable body220swings can be reduced. In the example shown inFIG. 6, a planar shape of each through-hole225is a square.

The opening section226piercing through the movable body220is provided in the movable body220. The opening section226is provided on the support axis Q in the plan view. In the example shown inFIG. 6, a planar shape of the opening section226is a rectangle.

The supporting section230is provided on the substrate210. The supporting section230is located in the opening section226. The supporting section230supports the movable body220. The supporting section230includes the first fixed section232, the second fixed section234, the first beam section241, the second beam section242, the third beam section243, and the fourth beam section244.

The first fixed section232and the second fixed section234are fixed to the substrate210. The first fixed section232and the second fixed section234are provided across the support axis Q in the plan view. In the example shown inFIG. 6, the first fixed section232is provided on the +X-axis direction side of the support axis Q and the second fixed section234is provided on the −X-axis direction side of the support axis Q.

Configuration of the Circuit Board

The configuration of the circuit board15configuring the circuit unit is explained with reference toFIGS. 7A, 7B, and 7C.FIG. 7Ais a plan view showing a disposition pattern of an insulating layer of the circuit board.FIG. 7Bis a sectional view taken along an A-A line inFIG. 7A.FIG. 7Cis a sectional view showing a mounted state of the acceleration sensor on the circuit board.

The circuit board15is a multilayer substrate in which a plurality of through-holes are formed. A glass epoxy substrate is used as the circuit board15. The circuit board15is not limited to the glass epoxy substrate and can be any rigid substrate on which pluralities of inertial sensors, electronic components, connectors, and the like can be mounted. For example, a composite substrate or a ceramic substrate may be used as the circuit board15.

On the first surface15fof the circuit board15, a plurality of electrode pads31,32, and33, to which a plurality of mounting terminals of the acceleration sensor functioning as the inertial sensor, the connector16, the angular velocity sensors17x,17y, and17z, and the like are respectively attached via connecting members13such as solder or a conductive adhesive, and a through-hole34are provided. An insulating layer14formed by, for example, resist resin is provided on the outer side of the plurality of electrode pads31,32, and33. In other words, the respective electrode pads31,32, and33are formed in openings of the insulating layer14. The first surface15fof the circuit board15includes a first region11(a first well) and second regions12(second wells and grooves), which are regions where the insulating layer14is not provided (a relief pattern).

The acceleration sensor18in this embodiment is formed in a square shape in a plan view from a direction right opposed to the first surface15fof the circuit board15. The plurality of mounting terminals are disposed on an opposed pair of sides of the square shape. That is, the plurality of electrode pads31are disposed on the first surface15fof the circuit board15corresponding to the mounting terminals. The acceleration sensor18is a sensor component of a surface mounting type (SMD: Surface Mount Device). In this embodiment, the acceleration sensor18is surface-mounted (SMT: Surface mount technology) on the plurality of electrode pads31, which are disposed on the first surface15fof the circuit board15, by soldering (the connecting members13).

The first region11is present in a center region further on the inner side than (inboard of) the electrode pads31on which the acceleration sensor18is mounted. The first region11is provided in a position overlapping (aligned with) the center of the acceleration sensor18. The second regions12are regions extending from the first region11to the outer side of the outer peripheral edge of the acceleration sensor18. That is, as shown inFIG. 7C, a gap S equivalent to the thickness of the insulating layer14is provided between the acceleration sensor18, to which mounting terminals18dof the acceleration sensor18and the electrode pads31are connected by the connecting members13such as solder, and the first surface15fof the circuit board15. The gap S continues from a position overlapping the center of the acceleration sensor18to the outer side of the outer peripheral edge of the acceleration sensor18.

That is, in the sensor unit100, by not providing the insulating layer14between the center region of the acceleration sensor18and the circuit board15, it is possible to set an interval (the gap S) between the acceleration sensor18and the circuit board15to be larger than when the insulating layer14is provided. Consequently, cleaning liquid for removing foreign matters present between the acceleration sensor18and the circuit board15easily enters between the acceleration sensor18and the circuit board15. Thus, a cleaning effect for the foreign matters can be improved. That is, since the foreign matters less easily remain in the interval (the gap S) between the acceleration sensor18and the circuit board15, stress generated in the acceleration sensor18by a change in a state of the foreign matters such as thermal expansion or thermal contraction of the remaining foreign matters by a temperature change is reduced. Therefore, it is possible to reduce deterioration in detection accuracy of the acceleration sensor18related to a temperature change such as temperature hysteresis of a bias signal.

Specifically, an effect of reducing deterioration in detection accuracy at the time when a temperature change is given to the acceleration sensor18of the sensor unit100including the circuit board15having such a configuration is shown inFIG. 8and explained. As a comparative example, the configuration of a circuit board on which the first region11and the second regions12are not provided is shown inFIGS. 9A and 9B. An output characteristic at the time when a temperature change is given to an acceleration sensor of a sensor unit including the circuit board is shown inFIG. 10.FIG. 8is a graph showing a temperature characteristic of an acceleration output of the sensor unit including the circuit board having the configuration according to the invention.FIG. 9Ais a plan view showing a disposition pattern of an insulating layer of the circuit board in the comparative example.FIG. 9Bis a B-B sectional view ofFIG. 9A.FIG. 10is a graph showing a temperature characteristic of an acceleration output of the sensor unit including the circuit board in the comparative example.

First, a circuit board15nin the comparative example has a configuration in which the first region11and the second regions12in the configuration explained above are not provided. That is, when the acceleration sensor18is connected to the circuit board15nby surface mounting, the acceleration sensor18is connected to the circuit board15nby, for example, soldering in a state in which a gap Sn between a bottom surface on the circuit board15nside of the acceleration sensor18and an insulating layer14nis small. When the gap Sn is small in this way, cleaning liquid for removing foreign matters present between the acceleration sensor18and the circuit board15nless easily enters between the acceleration sensor18and the circuit board15nand a cleaning effect for the foreign matters is deteriorated. Therefore, the foreign matters sometimes remain without being fully removed. When remaining foreign matters are present below the acceleration sensor18and a temperature change occurs in the remaining foreign matters, a state of the remaining foreign matters changes. In detail, the remaining foreign matters expand when temperature rises and contract when temperature falls. The acceleration sensor18sometimes detects a stress change due to a volume change of the remaining foreign matters. As a result, when the temperature is changed from a high-temperature side to a low-temperature side, a bias shift (temperature hysteresis of a bias signal (a detection output signal)) phenomenon of detected acceleration in a low-temperature region shown inFIG. 10occurs. In order to remove the foreign matters remaining in such as small gap Sn, it is necessary to increase the number of times of cleaning to repeat the cleaning or extend a cleaning time. As a result, a manufacturing manhour of the sensor unit increases.

On the other hand, in the circuit board15in this embodiment shown inFIG. 7Aand explained above, even if the acceleration sensor18is connected to the circuit board15by surface mounting, since the insulating layer14is not provided between the center region of the acceleration sensor18and the circuit board15, it is possible to set the interval (the gap S) between the acceleration sensor18and the circuit board15to be larger than when the insulating layer14is provided. It is possible to improve a cleaning effect for the remaining foreign matters and easily remove the remaining foreign matters by performing cleaning once or in a short time. Therefore, with the circuit board15in this embodiment shown inFIG. 7Aand explained above, it is possible to obtain an output characteristic (a bias) in which the bias shift phenomenon of the detected acceleration in the low-temperature region seen in the comparative example in which the remaining foreign matters are present is not seen as shown inFIG. 8.

Modifications of the First Region and the Second Region

In the circuit board15, the first region and the second region where the insulating layer14is not provided can be provided in various forms. Modifications of the first region and the second region are explained below in order.

First, a modification 1 of the first region and the second region is explained with reference toFIGS. 11A and 11B.FIG. 11Ais a plan view showing a disposition pattern of an insulating layer of a circuit board according to the modification 1.FIG. 11Bis a C-C sectional view ofFIG. 11A.

As shown inFIGS. 11A and 11B, a disposition pattern of an insulating layer14aof a circuit board15aaccording to the modification 1 includes a first region11aformed by a through-hole38present in a center region further on the inner side than the electrode pads31, on which the acceleration sensor18(seeFIG. 4) is mounted, and provided in a position overlapping the center of the acceleration sensor18. That is, the first region11ais a region where the insulating layer14ais not disposed because of the through-hole38. The through-hole38pierces through from the first surface15fto a second surface15rhaving a front-rear relation with the first surface15f. The through-hole38may not be circular and may be formed in any shape.

Since such a first region11a(the through-hole38) is provided, a large space can be provided on the bottom surface side of the acceleration sensor18. Consequently, it is possible to reduce the remaining of the foreign matters. Further, it is possible to further reduce the occurrence of the remaining foreign matters because the cleaning liquid sufficiently spreads.

A modification 2 of the first region and the second region is explained with reference toFIGS. 12A and 12B.FIG. 12Ais a plan view showing a disposition pattern of an insulating layer of a circuit board according to modification 2.FIG. 12Bis a D-D sectional view of FIG.12A.

As shown inFIGS. 12A and 12B, a disposition pattern of an insulating layer14bof a circuit board15baccording to the modification 2 includes a first region11bpresent in a center region further on the inner side than the electrode pads31, on which the acceleration sensor18(seeFIG. 4) is mounted, and provided in a position overlapping the center of the acceleration sensor18. Further, the disposition pattern of the insulating layer14bof the circuit board15baccording to the modification 2 includes second regions12b, which are regions extending from the first region11bto the outer side of the outer peripheral edge of the acceleration sensor18in positions at four corners of the outer peripheral edge of the acceleration sensor18. The first region11band the second regions12bare regions where the insulating layer14bis not disposed. In the modification 2, a recessed section39recessed from the first surface15fin the direction of the second surface15ris provided in positions overlapping the first region11band the second regions12b.

Since the recessed section39is provided in the first region11band the second regions12bin this way, a large space can be provided between the acceleration sensor18and the circuit board15b. Consequently, it is possible to reduce the remaining of the foreign matters. It is possible to further reduce the occurrence of the remaining foreign matters because the cleaning liquid sufficiently spreads.

A modification 3 of the first region and the second region is explained with reference toFIGS. 13A and 13B.FIG. 13Ais a plan view showing a disposition pattern of an insulating layer of a circuit board according to the modification 3.FIG. 13Bis a P part enlarged view ofFIG. 13A.

As shown inFIGS. 13A and 13B, a disposition pattern of an insulating layer14cof a circuit board15caccording to the modification 3 includes a first region11cpresent in a center region further on the inner side than the electrode pads31, on which the acceleration sensor18(seeFIG. 4) is mounted, and provided in a position overlapping the center of the acceleration sensor18. Further, the disposition pattern of the insulating layer14cof the circuit board15caccording to the modification 3 includes second regions12c, which are regions extending from the first region11cto the outer side of the outer peripheral edge of the acceleration sensor18. The first region11cand the second regions12care regions where the insulating layer14cis not disposed. The second regions12cin the modification 3 are disposed among the electrode pads31adjacent to one another and extending from the first region11cto the outer side of the outer peripheral edge of the acceleration sensor18.

Since the second regions12care provided among the electrode pads31adjacent to one another in this way, the area of the second regions12ccoupled to the first region11cincreases. It is possible to further reduce the occurrence of the remaining foreign matters because the cleaning liquid sufficiently spreads.

A modification 4 of the first region and the second region is explained with reference toFIGS. 14A and 14B.FIG. 14Ais a plan view showing a disposition pattern of an insulating layer of a circuit board according to the modification 4.FIG. 14Bis an E-E sectional view ofFIG. 13A.

As shown inFIGS. 14A and 14B, a disposition pattern of an insulating layer14dof a circuit board15daccording to the modification 4 includes a first region11dpresent in a center region further on the inner side than the electrode pads31, on which the acceleration sensor18(seeFIG. 4) is mounted, and provided in a position overlapping the center of the acceleration sensor18. In the first region11d, projecting sections14d2having a peripheral shape and not connected at four corners are provided between the center of the acceleration sensor18and the electrode pads31in the plan view.

The projecting sections14d2are disposed closer to the electrode pads31side than the center side of the acceleration sensor18. Since the projecting sections14d2are disposed closer to the electrode pads31side than the center side of the acceleration sensor18in this way, the foreign matters less easily reach the center of the acceleration sensor18where the foreign matters tend to remain.

The projecting sections14d2are desirably formed by the insulating layer14d. By forming the projecting sections14d2from the insulating layer14din this way, it is possible to easily form the projecting sections14d2in the same process as a process for forming the insulating layer14d.

The disposition pattern of the insulating layer14dof the circuit board15daccording to the modification 4 includes second regions12d, which are regions extending from the first region11dto the outer side of the outer peripheral edge of the acceleration sensor18in the positions at the four corners of the outer peripheral edge of the acceleration sensor18. The first region11dand the second regions12dare regions where the insulating layer14dis not disposed.

In the disposition pattern of the insulating layer14daccording to the modification 4 explained above, the projecting sections14d2are provided between the center of the acceleration sensor18and the electrode pads31. Consequently, it is possible to block, with the projecting sections14d2, the foreign matters intruding toward the center of the acceleration sensor18where the foreign matters tend to remain.

The projecting sections14d2may have a peripheral form or a peripheral and unconnected form.

A modification 5 of the first region and the second region is explained with reference toFIG. 15.

FIG. 15is a plan view showing a disposition pattern of an insulating layer of a circuit board according to the modification 5.

As shown inFIG. 15, a disposition pattern of an insulating layer14eof a circuit board15eaccording to the modification 5 includes a first region11epresent in a center region further on the inner side than the electrode pads31, on which an acceleration sensor18eis mounted, and provided in a position overlapping the center of the acceleration sensor18eand second regions12e, which are regions extending from the first region11eto the outer side of the outer peripheral edge of the acceleration sensor18e. The first region11eand the second regions12eare regions where the insulating layer14bis not disposed.

The acceleration sensor18eused in this modification has a square shape in the plan view. A plurality of mounting terminals are disposed on an opposed pair of sides of the square shape. That is, the plurality of electrode pads31are disposed in parallel along the opposed pair of sides. The first region11eand the second regions12eare respectively provided to traverse the pair of sides of the acceleration sensor18elocated in directions in which the electrode pads31are not arrayed.

In the disposition pattern of the insulating layer14eaccording to the modification 5 explained above, the second regions12ecan be provided to extend in directions in which the mounting terminals of the acceleration sensor18eare not disposed. Consequently, since the second regions12ehaving large width can be formed, it is possible to cause the cleaning liquid for foreign matters remaining in a gap between the acceleration sensor18eand the circuit board15eto easily flow in. Therefore, it is possible to easily discharge the foreign matters remaining in the gap between the acceleration sensor18eand the circuit board15eby performing cleaning.

Sixth Modification

A modification 6 of the first region and the second region is explained with reference toFIGS. 16A and 16B.FIG. 16Ais a plan view showing a disposition pattern of an insulating layer of a circuit board according to the modification 6.FIG. 16Bis an F-F sectional view ofFIG. 16A.

As shown inFIGS. 16A and 16B, a disposition pattern of the insulating layer14of a circuit board15gaccording to the modification 6 includes the first region11present in a center region further on the inner side than the electrode pads31, on which the acceleration sensor18is mounted, and provided in a position overlapping the center of the acceleration sensor18. Further, the disposition pattern of the insulating layer14of the circuit board15gaccording to the modification 6 includes the second regions12, which are regions extending from the first region11to the outer side of the outer peripheral edge of the acceleration sensor18in the positions at the four corners of the outer peripheral edge of the acceleration sensor18. The first region11and the second regions12are regions where the insulating layer14is not disposed. In the modification 6, a through-hole37piercing through from the first surface15fto the second surface15rof the circuit board15gis provided in the center of the first region11.

In the disposition pattern of the circuit board15gand the insulating layer14according to the modification 6 explained above, the through-hole37is provided in the center of the first region11, which is the region where the insulating layer14is not provided. Since the through-hole37is provided in this way, it is possible to cause the cleaning liquid for remaining foreign matters to flow into and discharge the cleaning liquid from the first region11between the acceleration sensor18and the circuit board15gthrough the through-hole37. Therefore, it is possible to improve the cleaning effect for the remaining foreign matters and eliminate the foreign matters.

Vehicle Positioning Device

A vehicle positioning device is explained with reference toFIGS. 17 and 18.FIG. 17is a block diagram showing an overall system of the vehicle positioning device.FIG. 18is a diagram schematically showing action of the vehicle positioning device.

A vehicle positioning device3000shown inFIG. 17is a device attached to a vehicle and used to perform positioning of the vehicle. The vehicle is not particularly limited and may be any one of a bicycle, an automobile (including a four-wheeled automobile and a motorbike), a train, an airplane, a ship, and the like. However, in this embodiment, the vehicle is explained as a four-wheeled automobile. The vehicle positioning device3000includes an inertial measurement unit3100(IMU), an arithmetic processing section3200, a GPS receiving section3300, a reception antenna3400, a position-information acquiring section3500, a position synthesizing section3600, a processing section3700, a communication section3800, and a display section3900. As the inertial measurement unit3100, for example, the sensor unit100explained above can be used.

The inertial measurement unit3100includes a three-axis acceleration sensor3110and a three-axis angular velocity sensor3120. The arithmetic processing section3200receives acceleration data from the acceleration sensor3110and receives angular velocity data from the angular velocity sensor3120, performs inertial navigation arithmetic processing on these data, and outputs inertial navigation positioning data (data including acceleration and a posture of the vehicle).

The GPS receiving section3300receives a signal (a GPS carrier wave; a satellite signal superimposed with position information) from a GPS satellite via the reception antenna3400. The position-information acquiring section3500outputs GPS positioning data representing the position (latitude, longitude, and altitude), the speed, the orientation of the vehicle positioning device3000(the vehicle) on the basis of the signal received by the GPS receiving section3300. The GPS positioning data includes status data indicating a reception state, reception time, and the like.

The position synthesizing section3600calculates, on the basis of the inertial navigation positioning data output from the arithmetic processing section3200and the GPS positioning data output from the position-information acquiring section3500, the position of the vehicle, specifically, in which position on the ground the vehicle is traveling. For example, even if the position of the vehicle included in the GPS positioning data is the same, if a posture of the vehicle is different according to the influence of inclination or the like of the ground as shown inFIG. 18, the vehicle is traveling in a different position on the ground. Therefore, an accurate position of the vehicle cannot be calculated only with the GPS positioning data. Therefore, the position synthesizing section3600calculates, using the inertial navigation positioning data (in particular, data concerning the posture of the vehicle), in which position on the ground the vehicle is traveling.

The calculation can be relatively easily performed by an arithmetic operation using a trigonometric function (a tilt with respect to the vertical direction is θ).

The position data output from the position synthesizing section3600is subjected to predetermined processing by the processing section3700and displayed on the display section3900as a positioning result. The position data may be transmitted to an external device by the communication section3800.

The vehicle positioning device3000is explained above. As explained above, such a vehicle positioning device3000includes the inertial measurement unit3100applied with the sensor unit100explained above, the GPS receiving section3300(a receiving section) configured to receive a satellite signal superimposed with position information from a positioning satellite, the position-information acquiring section3500(an acquiring section) configured to acquire position information of the GPS receiving section3300on the basis of the received satellite signal, the arithmetic processing section3200(a computing section) configured to compute a posture of the vehicle on the basis of inertial navigation positioning data (inertial data) output from the inertial measurement unit3100, and the position synthesizing section3600(a calculating section) configured to calculate a position of the vehicle by correcting the position information on the basis of the computed posture. Consequently, it is possible to enjoy the effects of the sensor unit100(the inertial measurement unit: IMU) explained above. The vehicle positioning device3000having high reliability is obtained.

Electronic Device

An electronic device including the sensor unit100is explained in detail on the basis ofFIGS. 19 to 21.

First, a mobile personal computer, which is an example of the electronic device, is explained with reference toFIG. 19.FIG. 19is a perspective view schematically showing the configuration of the mobile personal computer, which is an example of the electronic device.

In this figure, a personal computer1100is configured by a main body section1104including a keyboard1102and a display unit1106including a display section1108. The display unit1106is turnably supported with respect to the main body section1104via a hinge structure section. The sensor unit100functioning as the inertial measurement unit is incorporated in such a personal computer1100. A control section1110can perform control such as posture control on the basis of detection data of the sensor unit100.

A smartphone (a portable telephone), which is an example of the electronic device, is explained with reference toFIG. 20.FIG. 20is a perspective view schematically showing the configuration of the smartphone (the portable telephone), which is an example of the electronic device.

In this figure, the sensor unit100explained above is incorporated in a smartphone1200. Detection data (acceleration data and angular velocity data) detected by the sensor unit100is transmitted to a control section1201of the smartphone1200. The control section1201includes a CPU (Central Processing Unit). The control section1201can recognize a posture and a behavior of the smartphone1200from the received detection data, change a display image displayed on a display section1208, emit alarm sound and sound effect, and drive a vibration motor to vibrate a main body. In other words, the control section1201can perform motion sensing of the smartphone1200, change display content from a measured posture and a measured behavior, and generate sound, vibration, and the like. In particular, when a game application is executed, a user can enjoy presence closer to reality.

A digital still camera, which is an example of the electronic device, is explained with reference toFIG. 21.FIG. 21is a perspective view showing the configuration of the digital still camera, which is an example of the electronic device. In this figure, connection to an external device is briefly shown.

A display section1310is provided on the back of a case (a body)1302of a digital still camera1300. The display section1310is configured to perform display on the basis of an imaging signal output by a CCD. The display section1310also functions as a finder that displays an object and an electronic image. A light receiving unit1304including an optical lens (an imaging optical system) and a CCD is provided on the front surface side (the rear surface side inFIG. 21) of the case1302.

When a photographer confirms an object image displayed on the display section1310and presses a shutter button1306, an imaging signal of the CCD at that point in time is transferred to and stored in a memory1308. In this digital still camera1300, video signal output terminals1312and an input/output terminal for data communication1314are provided on a side surface of the case1302. As shown inFIG. 21, a television monitor1430is connected to the video signal output terminals1312according to necessity. A personal computer1440is connected to the input/output terminal for data communication1314according to necessity. Further, an imaging signal stored in the memory1308is output to the television monitor1430and the personal computer1440according to predetermined operation. The sensor unit100functioning as the inertial measurement unit is incorporated in the digital still camera1300. A control section1316can perform control such as camera shake correction on the basis of detection data of the sensor unit100.

Such an electronic device has excellent reliability because the electronic device includes the sensor unit100and the control section1110,1201, and1316.

The electronic device including the sensor unit100can be applied to, besides the personal computer shown inFIG. 19, the smartphone (the portable telephone) shown inFIG. 20, and the digital still camera shown inFIG. 21, for example, a tablet terminal, a watch, an inkjet ejecting device (e.g., an inkjet printer), a laptop personal computer, a television, a video camera, a video tape recorder, a car navigation device, a pager, an electronic notebook (including an electronic notebook having a communication function), an electronic dictionary, an electronic calculator, an electronic game device, a word processor, a workstation, a videophone, a television monitor for crime prevention, an electronic binocular, a POS terminal, medical devices (e.g., an electronic thermometer, a manometer, a blood glucose meter, an electrocardiographic device, an ultrasonic diagnosis device, and an electronic endoscope), a fish finder, various measurement devices, meters (e.g., meters of a vehicle, an airplane, and a ship), a flight simulator, a seismometer, a pedometer, a clinometer, a vibration meter that measures vibration of a hard disk, a posture control device for a robot and a flying body such as a drone, a control device used for inertial navigation for automatic driving of an automobile, and the like.

Portable Electronic Device

A portable electronic device including the sensor unit100is explained in detail with reference toFIGS. 22 and 23. A wristwatch-type activity meter (an active tracker) is explained below as an example of the portable electronic device.

As shown inFIG. 22, a wrist device1400, which is the wristwatch-type activity meter (the active tracker), is worn on a part (a subject) such as a wrist of a user by a band1401. The wrist device1400includes a digital display section1402and is capable of performing wireless communication. The sensor unit100according to the invention explained above is incorporated in the wrist device1400together with other sensors and the like as a sensor that measures acceleration and angular velocity.

The wrist device1400includes a case1403in which at least the sensor unit100(not shown inFIG. 22) is housed, a processing section1410(seeFIG. 23) housed in the case1403and configured to process output data from the sensor unit100, the display section1402housed in the case1403, and a light transmissive cover1404closing an opening section of the case1403. A bezel1405is provided on the outer circumferential side located on the case1403side of the light transmissive cover1404. A plurality of operation buttons1406and1407are provided on a side surface of the case1403. The wrist device1400is explained more in detail below with reference toFIG. 23as well.

An acceleration sensor1408included in the sensor unit100detects accelerations in respective three axial directions crossing (ideally, orthogonal to) one another and outputs signals (acceleration signals) corresponding to the magnitudes and the directions of the detected three-axis accelerations. An angular velocity sensor1409included in the sensor unit100detects respective angular velocities in respective three axial directions crossing (ideally, orthogonal to) one another and outputs signals (angular velocity signals) corresponding to the magnitudes and the directions of the detected three-axis angular velocities.

A liquid crystal display (LCD) configuring the display section1402displays, according to various detection modes, for example, position information obtained using a GPS sensor1411and a terrestrial magnetism sensor1412, exercise information such as a movement amount and an exercise amount obtained using the acceleration sensor1408or the angular velocity sensor1409, biological information such as a pulse rate obtained using a pulse sensor1413, time information such as present time, or the like. The liquid crystal display can also display an environmental temperature obtained using a temperature sensor1414.

A communication section1415performs various kinds of control for establishing communication between a user terminal and a not-shown information terminal. The communication section1415includes a transceiver corresponding to a short range wireless communication standard such as a Bluetooth (registered trademark) (including BTLE: Bluetooth Low Energy), Wi-Fi (registered trademark) (Wireless Fidelity), ZigBee (registered trademark), NFC (Near field communication), or ANT+ (registered trademark) and a connector corresponding to a communication bus standard such as a USB (Universal Serial Bus).

The processing section1410(a processor) is configured by, for example, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), or an ASIC (Application Specific Integrated Circuit). The processing section1410executes various kinds of processing on the basis of computer programs stored in a storing section1416and signals input from an operation section1417(e.g., operation buttons1406and1407). The processing executed by the processing section1410includes data processing for output signals of a satellite positioning system including the GPS sensor1411, the terrestrial magnetism sensor1412, a pressure sensor1418, the acceleration sensor1408, the angular velocity sensor1409, the pulse sensor1413, the temperature sensor1414, and a clocking section1419, display processing for causing the display section1402to display an image, sound output processing for causing a sound output section1420to output sound, communication processing for performing communication with an information terminal via the communication section1415, and power control processing for supplying electric power from a battery1421to the respective sections.

Such a wrist device1400can have at least the following functions.1. Moving distance: measuring a total distance and a moving track from a measurement start with a highly accurate GPS function.2. Pace: displaying a present traveling pace from a pace distance measurement value.3. Average speed: calculating and displaying average speed from a traveling start to the present.4. Altitude: measuring and displaying altitude with a GPS function.5. Stride: measuring and displaying a stride even in a tunnel and the like where a GPS radio wave does not reach.6. Pitch: measuring and displaying a pitch per one minute.7. Heart rate: measuring and displaying a heart rate with a pulse sensor.8. Gradient: measuring and displaying a gradient of the ground in training and trail running in a mountainous area.9. Auto lap: automatically performing lap measurement when traveling a fixed distance or a fixed time set beforehand.10. Exercise consumed calorie: displaying consumed calorie.11. Steps: displaying a total of steps from an exercise start.

The wrist device1400can be widely applied to a running watch, a runner's watch, a runner's watch adapted to multiple sports such as duathlon and triathlon, an outdoor watch, and a GPS watch mounted with a satellite positioning system, for example, a GPS.

In the above explanation, the GPS (Global Positioning System) is used as the satellite positioning system. However, another global navigation satellite system (GNSS) may be used. For example, one or two or more of satellite positioning systems such as an EGNOS (European Geostationary-Satellite Navigation Overlay Service), a QZSS (Quasi Zenith Satellite System), a GLONASS (Global Navigation Satellite System), a GALILEO, and a BeiDou (BeiDou Navigation Satellite system) may be used. A satellite-based augmentation system (SBA) such as a WARS (Wide Area Augmentation System) or an EGNOS (European Geostationary-Satellite Navigation Overlay Service) may be used in at least one of the satellite positioning systems.

Such a wrist device1400functioning as the portable electronic device has excellent reliability because the wrist device1400includes the sensor unit100and the processing section1410.

Vehicle

A vehicle including the sensor unit100is explained in detail with reference toFIG. 24.FIG. 24is a perspective view showing the configuration of an automobile, which is an example of the vehicle.

As shown inFIG. 24, the sensor unit100is incorporated in an automobile1500. For example, a posture of a vehicle body1501can be detected by the sensor unit100.

A detection signal of the sensor unit100is supplied to a vehicle body posture control device1502functioning as a control section that controls a posture of the vehicle body. The vehicle body posture control device1502can detect a posture of the vehicle body1501on the basis of the signal, control hardness of a suspension according to a result of the detection, and function as a brake system to control brakes of respective wheels1503. Besides, the sensor unit100can be widely applied to a keyless entry system, an immobilizer, a car navigation system, a car air conditioner, an antilock brake system (ABS), an airbag, a tire pressure monitoring system (TPMS), an engine control system (an engine system), a control device for inertial navigation for automobiles, and an electronic control unit (ECU) for a battery monitor and the like of a hybrid automobile and an electric automobile.

Besides the illustrations explained above, the sensor unit100applied to the vehicle can be used in posture control of a bipedal walking robot, a train, and the like, posture control of remote-controlled or autonomous flying bodies such as radio-controlled airplane, a radio-controlled helicopter, and a drone, posture control of an agricultural machine, a construction machine, and the like, and control of a rocket, an artificial satellite, a ship, an AGV (automatic guided vehicle), and the like. As explained above, in realizing the posture control of the various vehicles, the sensor unit100and control sections (not shown inFIG. 24) of the vehicles are incorporated in the vehicles.

Such a vehicle has excellent reliability because the vehicle includes the sensor unit100and the control section (e.g., the vehicle body posture control device1502functioning as the posture control section).

Traveling Supporting System

A traveling supporting system including the sensor unit100is explained below with reference toFIGS. 25 and 26.FIG. 25is a diagram showing a schematic configuration of the traveling supporting system.FIG. 26is a functional block diagram showing the schematic configuration of the traveling supporting system.

Schematic Configuration of the Traveling Supporting System

As shown inFIG. 25, a traveling supporting system4000includes control devices4100respectively mounted on a plurality of vehicles and an information processing device4200.

The control device4100is mounted on a vehicle that performs automatic driving for automatically controlling at least any one of acceleration, braking, and steering (hereinafter, automatic driving vehicle) and performs communication with the information processing device4200. The information processing device4200is, for example, a server device. The information processing device4200collects vehicle information transmitted from the control devices4100mounted on a plurality of automatic driving vehicles and transmits information obtained on the basis of the collected vehicle information to the control devices4100. The information processing device4200may be configured from one server device or may be configured from a plurality of server devices.

Schematic Configuration of the Control Device

A schematic configuration of the control device4100is explained with reference toFIG. 26. The control device4100is mounted on an automatic driving vehicle. As shown inFIG. 26, the control device4100includes an automatic driving unit4010, a communicator4020, an ADAS (Advanced Driver Assistance Systems) locator4030, an HMI (Human Machine Interface) system4040, a periphery monitoring sensor4050, and a vehicle control unit4060. The automatic driving unit4010functioning as a control section, the communicator4020, the ADAS locator4030, the HMI system4040, and the vehicle control unit4060are connected to, for example, an in-vehicle LAN and can exchange information with one another through communication.

The communicator4020performs communication with the outside of the vehicle. The communicator4020can perform wireless communication with, for example, at least one of a vehicle-mounted communicator mounted on a peripheral vehicle of the vehicle and a roadside machine set on a roadside. For example, the communicator4020can acquire position information, traveling speed information, and the like of the peripheral vehicle of the vehicle through inter-vehicle communication with the vehicle-mounted communicator and the roadside machine.

The communicator4020performs communication with the information processing device4200. When performing communication with the information processing device4200, the communicator4020only has to be configured to perform communication with the information processing device4200with a vehicle-mounted communication module used for telematics communication such as a DCM (Data Communication Module) via a communication network used in the telematics communication. The communicator4020may be configured to perform communication with the information processing device4200via the roadside machine and a communication network between the roadside machine and the information processing device4200. The communicator4020outputs information acquired from the information processing device4200to the in-vehicle LAN and transmits vehicle information transmitted from the automatic driving unit4010via the in-vehicle LAN.

A vehicle-mounted communication module that performs wireless communication with at least one of the vehicle-mounted communicator mounted on the peripheral vehicle and the roadside machine set on the roadside and the vehicle-mounted communication module used for the telematics communication may be separately provided or may be integrally provided.

The ADAS locator4030includes a GNSS (Global Navigation Satellite System) receiver4031, the sensor unit100explained above, and a map database (hereinafter, DB)4033in which map data is stored. The GNSS receiver4031receives positioning signals from a plurality of artificial satellites. The sensor unit100includes, for example, a three-axis gyro sensor and a three-axis acceleration sensor. The map DB4033is a nonvolatile memory and has stored therein map data such as link data, node data, road shapes, and structures.

The ADAS locator4030combines a positioning signal received by the GNSS receiver4031and a measurement result of the sensor unit100to thereby sequentially position vehicle positions of the vehicle mounted with the ADAS locator4030. For the positioning of the vehicle position, a traveling distance calculated from pulse signals sequentially output from a wheel speed sensor (not shown inFIG. 26) mounted on the vehicle may also be used. The ADAS locator4030outputs the positioned vehicle position to the in-vehicle LAN. The ADAS locator4030reads out the map data from the map DB4033and outputs the map data to the in-vehicle LAN. The ADAS locator4030may acquire map data from the outside of the vehicle using a vehicle-mounted communication module (not shown inFIG. 26) such as a DCM mounted on the vehicle.

The HMI system4040includes, as shown inFIG. 26, an HCU (Human Machine Interface Control Unit)4041, an operation section4042, a steering sensor4043, a display device4044, and a sound output device4045. The HMI system4040receives input operation from a driver of the vehicle, presents information to the driver of the vehicle, and detects a state of the driver of the vehicle.

The operation section4042is a switch group operated by the driver of the vehicle. The operation section4042is used for performing various kinds of setting. For example, as the operation section4042, there are a steering switch provided in a spoke section a steering wheel of the vehicle, a touch switch integrated with the display device4044, and the like.

The steering sensor4043is a sensor for detecting that an occupant is touching the steering wheel of the vehicle. Examples of the steering sensor4043include a touch sensor provided in the steering wheel and a steering torque sensor that detects steering torque of the steering wheel of the vehicle. A detection result in the steering sensor4043is output to the HCU4041.

As the display device4044, there are, for example, a combination meter, a CID (Center Information Display), and an HUD (Head-Up Display). The combination meter is disposed in front of a driver's seat of the vehicle. The CID is disposed above a center cluster in a vehicle interior of the vehicle. The combination meter and the CID display various images for information presentation on a display screen of a display on the basis of image data acquired from the HCU4041. The HUD projects light of an image based on the image data acquired from the HCU4041onto a projection region specified in a windshield of the vehicle. The light of the image reflected to the vehicle interior side by the windshield is sensed by the driver seated on the driver's seat. The driver is capable of visually recognizing a virtual image of the image projected by the HUD while superimposing the virtual image on an external scene in front of the vehicle.

As the sound output device4045, there is, for example, an audio speaker. The audio speaker is disposed in, for example, a lining of a door of the vehicle. The audio speaker presents information to the occupant such as the driver with reproduced sound.

The HCU4041includes a CPU, memories such as a ROM and a RAM, an I/O, and a bus that connects the foregoing. The HCU4041executes a control program stored in the memories to execute various kinds of processing. For example, the HCU4041causes, according to an instruction from the automatic driving unit4010, at least one of the display device4044and the sound output device4045to present information. A part or all of functions executed by the HCU4041may be configured in a hardware manner by one or a plurality of ICs or the like.

The periphery monitoring sensor4050detects obstacles including moving objects such as pedestrians, animals other than humans, bicycles, motorbikes, and other vehicles and stationary objects such as fallen objects on roads, guardrails, curbstones, and trees. Besides, the periphery monitoring sensor4050detects road markings such as traveling section lines and stop lines. The periphery monitoring sensor4050is a sensor such as a periphery monitoring camera that images a predetermined range around the vehicle, a millimeter wave radar that transmits a probing wave to a predetermined range around the vehicle, a sonar, or an LIDAR (Light Detection and Ranging/Laser Imaging Detection and Ranging).

As the periphery monitoring camera, a stereo camera may be used or a monocular camera may be used. The periphery monitoring camera sequentially outputs sequentially captured images to the automatic driving unit4010as sensing information. The sensor that transmits a probing wave such as the sonar, the millimeter wave radar, or the LIDAR sequentially outputs scanning results based on reception signals obtained when a reflected wave reflected by an obstacle is received to the automatic driving unit4010as sensing information. A plurality of kinds of periphery monitoring sensors4050may have overlapping sensing ranges. For example, sensing of the front of the vehicle may be performed concurrently using the periphery monitoring camera and the millimeter wave radar.

The vehicle control unit4060is an electronic control device that performs at least one of acceleration and deceleration control and steering control of the vehicle. As the vehicle control unit4060, there are a steering ECU that performs the steering control, a power unit control ECU that performs the acceleration and deceleration control, a brake ECU, and the like. The vehicle control unit4060acquires detection signals output from sensors such as an accelerator position sensor, a brake stepping force sensor, a steering angle sensor, and a wheel speed sensor and outputs control signals to traveling control devices such as an electronic control throttle, a brake actuator, an EPS (Electric Power Steering) motor. The vehicle control unit4060is capable of outputting the detection signals of the sensors to the in-vehicle LAN.

The automatic driving unit4010functioning as the control section includes a CPU, a volatile memory, a nonvolatile memory, an I/O, and a bus that connects the foregoing. The automatic driving unit4010executes a control program stored in the nonvolatile memory to execute various kinds of processing. For example, the automatic driving unit4010recognizes a traveling environment of the vehicle from a sensing result in the periphery monitoring sensor4050. Besides, the automatic driving unit4010controls the vehicle control unit4060to thereby execute driving operation on behalf of the driver. The automatic driving unit4010is equivalent to a traveling supporting device. Apart or all of functions executed by the automatic driving unit4010may be configured in a hardware manner by one or a plurality of ICs or the like.

The automatic driving unit4010functioning as the control section can instruct the vehicle control unit4060on the basis of a detection signal detected by the sensor unit100to control at least any one of acceleration, braking, and steering. The automatic driving unit4010can switch, according to a change of the detection signal detected by the sensor unit100, whether automatic driving is carried out or not. With the automatic driving unit4010functioning as the control section that controls at least any one of acceleration, braking, and steering, it is possible to accurately switch, according to a change of the detection signal detected by the sensor unit100, whether automatic driving is carried out or not.

Such a traveling supporting system4000has excellent reliability because the traveling supporting system4000includes the sensor unit100and the automatic driving unit4010functioning as the traveling supporting device including the sensor unit100.

Head-Mounted Display Device

A head-mounted display device functioning as an example of a display device including the sensor unit100is explained below with reference toFIG. 27.FIG. 27is an explanatory diagram showing a schematic configuration of the head-mounted display device.

As shown inFIG. 27, a head-mounted display device5000includes an image display section520configured to cause a user to visually recognize a virtual image in a state in which the image display section520is worn on the head of the user and a control device510configured to control the image display section520. The control device510also functions as a controller for the user to operate the head-mounted display device5000.

The image display section520is a wearing body worn on the head of the user. In this embodiment, the image display section520includes a frame502(a main body) having an eyeglass shape. The frame502includes a right holding section521and a left holding section523. The right holding section521is a member provided to extend from an end portion ER, which is the other end, of a right optical-image-display section526to a position corresponding to the temporal region of the user when the user wears the image display section520. Similarly, the left holding section523is a member provided to extend from an end portion EL, which is the other end, of a left optical-image-display section528to a position corresponding to the temporal region of the user when the user wears the image display section520. The right holding section521is in contact with the right ear or the vicinity of the right ear on the head of the user and the left holding section523is in contact with the left ear or the vicinity of the left ear on the head of the user to hold the image display section520on the head of the user.

A right display driving section522, a left display driving section524, the right optical-image display section526, the left optical-image display section528, and a microphone563are provided in the frame502. In this embodiment, the frame502of an eyeglass type is illustrated as an example of the main body. The shape of the main body is not limited to the eyeglass type and can be any type worn on the head of the user and fixed. The shape of the main body is more desirably a shape worn to extend in front of the left and right eyes of the user. For example, besides the eyeglass type explained here, the shape may be a snow goggles-like shape that covers an upper part of the face of the user or may be a shape disposed in front of the respective left and right eyes of the user like a binocular.

The frame502of the eyeglass type includes a right section502A located in front of the right eye of the user and a left section502B located in front of the left eye of the user. The frame502has a shape formed by coupling the right section502A and the left section502B in a bridge section502C (a coupling section). The bridge section502C couples the right section502A and the left section502B in a position corresponding to the middle of the forehead of the user when the user wears the image display section520.

The right section502A and the left section502B are respectively coupled to temple sections502D and502E. The temple sections502D and502E support the frame502on the head of the user like temples of an eyeglass. In this embodiment, the temple section502D is configured by the right holding section521and the temple section502E is configured by the left holding section523.

The right optical-image display section526is disposed in the right section502A. The left optical-image display section528is disposed in the left section502B. The right optical-image display section526and the left optical-image display section528are respectively located in front of the right and left eyes of the user when the user wears the image display section520.

The right display driving section522and the left display driving section524are disposed on sides opposed to the head of the user when the user wears the image display section520. The right display driving section522and the left display driving section524are collectively simply referred to as “display driving sections” as well. The right optical-image display section526and the left optical-image display section528are collectively simple referred to as “optical-image display sections” as well. The display driving sections522and524include liquid crystal displays, projection optical systems, and the like not shown inFIG. 27.

In the following explanation in this embodiment, dimming plates at least having light transmissivity enough for the user wearing the image display section520to visually recognize an outside scene are used. The dimming plates protect a right light guide plate and a left light guide plate, which are optical elements, and prevent damage, adhesion of stain, and the like to the right light guide plate and the left light guide plate. The dimming plates may be detachably attachable to the right optical-image display section526and the left optical-image display section528. A plurality of kinds of dimming plates may be able to be replaced and attached. The dimming plates may be omitted.

A camera unit503is provided in the frame502. The camera unit503includes a camera pedestal section503C on which an upper camera561is disposed and arm sections503A and503B configured to support the camera pedestal section503C. The arm section503A is turnably coupled to the right holding section521by a hinge521A provided at a distal end portion AP of the right holding section521. The arm section503B is turnably coupled to the left holding section523by a hinge523A provided at a distal end portion AP of the left holding section523. Therefore, the camera unit503as a whole is turnable in a direction indicated by arrows K inFIG. 27, that is, up and down in a mounted state of the head-mounted display. The camera unit503is in contact with the frame502at a lower end of a turning range. An upper end of the turning range of the camera unit503is determined by, for example, specifications of the hinges521A and523A.

The camera pedestal section503C is a plate-like or bar-like member located across upper parts of the right section502A, the left section502B, and the bridge section502C. The upper camera561is embedded and set in a position above the bridge section502C. The upper camera561is a digital camera including an imaging element such as a CCD or a CMOS and an imaging lens. The upper camera561may be a monocular camera or may be a stereo camera.

The upper camera561images at least a part of an outside scene in a front side direction of the head-mounted display device5000, in other words, a visual field direction of the user in a state in which the user wears the image display section520. The width of an angle of view of the upper camera561can be set as desired. However, for example, at the lower end of the turning range of the camera unit503, an imaging range of the upper camera561desirably includes an external world visually recognized by the user through the right optical-image display section526and the left optical-image display section528. Further, the imaging range of the upper camera561is more desirably set such that the upper camera561can image an entire visual field of the user through the dimming plates.

The image display section520is connected to the control device510via a connecting section540. The connecting section540includes a main body cord548connected to the control device510, a right cord542, a left cord544, and a coupling member546. The right cord542and the left cord544are two cords branching from the main body cord548. The right cord542is inserted into a housing of the right holding section521from the distal end portion AP in the extending direction of the right holding section521and connected to the right display driving section522. Similarly, the left cord544is inserted into a housing of the left holding section523from the distal end portion AP in the extending direction of the left holding section523and connected to the left display driving section524.

The coupling member546is provided at a branching point of the main body cord548and the right cord542and the left cord544. The coupling member546includes a jack for connecting an earphone plug530. Cords of a right earphone532and a left earphone534extend from the earphone plug530. The microphone563is provided in the vicinity of the earphone plug530. The cords are collected as one cord from the earphone plug530to the microphone563. The cords branch from the microphone563and are respectively connected to the right earphone532and the left earphone534.

The microphone563is disposed such that a sound collecting section of the microphone563faces a visual line direction of the user. The microphone563collects sound and outputs a sound signal to a sound processing section (not shown inFIG. 27). The microphone563may be, for example, a monaural microphone or may be a stereo microphone, may be a microphone having directivity, or may be a nondirectional microphone.

The right cord542, the left cord544, and the main body cord548only have to be cords capable of transmitting digital data and can be configured by, for example, a metal cable or an optical fiber. The right cord542and the left cord544may be collected as one cord.

The image display section520and the control device510transmit various signals via the connecting section540. Connectors (not shown inFIG. 27) that fit with each other are provided at the end portion of the main body cord548on the opposite side of the coupling member546and the control device510. The control device510and the image display section520can be connected and separated by fitting the connector of the main body cord548and the connector of the control device510and releasing the fitting.

The control device510controls the head-mounted display device5000. The control device510includes a determination key511, a lighting section512, a display switching key513, a luminance switching key515, a direction key516, a menu key517, and switches including a power switch518. The control device510includes a track pad514that the user operates with a finger.

The determination key511detects pressing operation and outputs a signal for determining content of operation by the control device510. The lighting section512includes a light source such as an LED (Light Emitting Diode) and notifies, with a lighting state of the light source, an operation state (e.g., ON/OFF of a power supply) of the head-mounted display device5000. The display switching key513outputs, according to pressing operation, for example, a signal for instructing switching of a display mode of an image.

The track pad514includes an operation surface on which a touch operation is detected and outputs an operation signal according to the operation on the operation surface. A detection type on the operation surface is not limited. An electrostatic type, a pressure detection type, an optical type, and the like can be adopted. The luminance switching key515outputs, according to pressing operation, a signal for instructing an increase and a decrease in the luminance of the image display section520. The direction key516outputs an operation signal according to pressing operation of the key corresponding to upper, lower, left, and right directions. The power switch518is a switch that switches ON/OFF of the power supply of the head-mounted display device5000.

Two motion sensors are attached to the frame502. The motion sensors in this embodiment are inertial sensors and are specifically a first sensor566and a second sensor568. The first sensor566is disposed at the end on the temple section502D side in the right section502A. The second sensor568is disposed at the end on the temple section502E side in the left section502B. That is, the first sensor566and the second sensor568are located further on one side than the center of the head in a mounted state of the head-mounted display device5000. The first sensor566and the second sensor568are inertial sensors such as an acceleration sensor and an angular velocity sensor (a gyro sensor). In this embodiment, the sensor unit100explained above including the three-axis gyro sensor and the three-axis acceleration sensor is used. The first sensor566and the second sensor568respectively detect, at measurement reference points of incorporated detecting mechanisms, for example, rotation (a pitch) around the X axis, rotation (a yaw) around the Y axis, and rotation (a roll) around the Z axis.

One sensor of the first sensor566and the second sensor568is present on one side of the center of the head of the user. The other sensor is present on the other side of the center of the head of the user. Specifically, the first sensor566is present on the right side of the head of the user. The second sensor568is present on the left side of the head of the user. In this embodiment, the center of the head indicates the center of the head on a horizontal plane perpendicular to the height of the user. The positions on the horizontal plane of the first sensor566and the second sensor568are present on the right side and the left side across the center of the head on the horizontal plane.

The head-mounted display device5000functioning as an example of the display device having such a configuration includes the image display section520configured to irradiate image light on the eyes of the user and the first sensor566and the second sensor568functioning as a plurality of motion sensors. One of the first sensor566and the second sensor568is located further on one side than the center of the head in the mounted state. The other motion sensor is located further on the other side than the center of the head in the mounted state. Therefore, when the head of the user moves, it is possible to quickly calculate a movement amount, a direction of the movement, and the like in a motion center.

In the head-mounted display device5000, one of the first sensor566and the second sensor568is located further on the left side than the center of the head in the mounted state. The other motion sensor is located further on the right side than the center of the head in the mounted state. Therefore, it is possible to quickly calculate a movement in the motion center of the head on the basis of detection results of the motion sensors.

Such a head-mounted display device5000functioning as an example of the display device has excellent reliability because the head-mounted display device5000includes the sensor unit100as the first sensor566and the second sensor568.

The sensor unit, the vehicle positioning device, the electronic device, the portable electronic device, the vehicle, and the display device are explained on the basis of the embodiment shown in the figures. However, the invention is not limited to the embodiment. The components of the sections can be replaced with any components having the same functions. Any other components may be added to the invention.

Contents derived from the embodiment explained above are described below as aspects.

First Aspect

A sensor unit according to this aspect includes: an inertial sensor; a circuit board including, on a first surface, a plurality of electrode pads to which a plurality of mounting terminals of the inertial sensor are respectively attached via connecting members; and a case, on an inside of which the circuit board is housed. The first surface of the circuit board includes an insulating layer provided on an outer side of the plurality of electrode pads in a plan view, includes, in a portion overlapping a center region further on an inner side than the mounting terminals of the inertial sensor in the plan view, a first region where the insulating layer is not provided, and includes, from the first region to an outer side of the inertial sensor in the plan view, a second region where the insulating layer is not provided.

According to this aspect, the sensor unit includes the inertial sensor, the circuit board, and the case. The plurality of electrode pads to which the plurality of mounting terminals of the inertial sensor are respectively attached via the connecting members are provided on the first surface of the circuit board. The circuit board is housed on the inside of the case. The insulating layer is provided on the outer side of the electrode pads on the first surface of the circuit board. In other words, the electrode pads are formed in an opening section of the insulating layer. The first surface of the circuit board includes the first region and the second region where the insulating layer is not provided. The first region is the center region further on the inner side than the mounting terminals of the inertial sensor. The second region is a region extending from the first region to the outer side of the inertial sensor.

That is, by not providing the insulating layer between the center region of the inertial sensor and the circuit board, the sensor unit is configured to set an interval (a gap) between the inertial sensor and the circuit board to be larger than when the insulating layer is provided. Consequently, cleaning liquid for removing foreign matters present between the inertial sensor and the circuit board easily enters between the inertial sensor and the circuit board. It is possible to improve a cleaning effect for the foreign matters. Consequently, since the foreign matters less easily remain in the interval (the gap) between the inertial sensor and the circuit board, stress generated in the inertial sensor by a change in a state (e.g., thermal expansion or thermal contraction) of the foreign matters by a temperature change decreases. Therefore, it is possible to reduce occurrence of temperature hysteresis of a bias signal (a detection output signal) due to the remaining of the foreign matters. It is possible to provide an inertial sensor capable of performing highly accurate detection.

Second Aspect

In the sensor unit according to the first aspect, it is preferable that recessed sections are provided in the first region and the second region of the first surface of the circuit board.

According to this aspect, the recessed sections are provided in the first region and the second region on the first surface of the circuit board. Consequently, since it is possible to further expand the interval between the inertial sensor and the circuit board, the foreign matters much less easily remain.

Third Aspect

In the sensor unit according to the first aspect, it is preferable that, in the circuit board, a through-hole piercing through the circuit board is provided in the first region.

According to this aspect, since the through-hole is provided in the first region of the circuit board, it is possible to reduce the remaining of the foreign matters.

Fourth Aspect

In the sensor unit according to the first aspect, it is preferable that the second region is provided between the electrode pads adjacent to each other.

According to this aspect, the second region is provided between the electrode pads adjacent to each other. Consequently, the area of the second region coupled to the first region increases. It is possible to further reduce the occurrence of the remaining foreign matters because the cleaning liquid sufficiently spreads.

Fifth Aspect

In the sensor unit according to the first aspect, it is preferable that a peripheral projecting section or an unconnected projecting section is provided between a center of the inertial sensor and the electrode pads in the plan view.

According to this aspect, the peripheral projecting section or the unconnected projecting section is provided between the center of the inertial sensor and the electrode pads. Consequently, it is possible to block, with the projecting section, the foreign matters intruding toward the center of the inertial sensor where the foreign matters tend to remain.

Sixth Aspect

In the sensor unit according to the fifth aspect, it is preferable that the peripheral projecting section or the unconnected projecting section is closer to the electrode pads side than the center side of the inertial sensor.

According to this aspect, the peripheral projecting section or the unconnected projecting section is disposed closer to the electrode pads side than the center side of the inertial sensor. Consequently, the foreign matters less easily reach the center of the inertial sensor where the foreign matters tend to remain.

Seventh Aspect

In the sensor unit according to the fifth aspect, it is preferable that the peripheral projecting section or the unconnected projecting section is an insulating layer.

According to this aspect, the peripheral projecting section or the unconnected projecting section is formed by the insulating layer. Consequently, it is possible to easily form the peripheral projecting section or the unconnected projecting section.

Eighth Aspect

In the sensor unit according to the first aspect, it is preferable that the inertial sensor has a square shape in the plan view, and the plurality of mounting terminals are disposed on an opposed pair of sides of the square shape.

According to this aspect, the mounting terminals of the inertial sensor having the square shape are arrayed on the opposed pair of sides of the square shape. Therefore, it is possible to provide the second region in the directions of the other pair of sides of the inertial sensor on which the mounting terminals are not disposed. Consequently, since the second region having large width can be formed, it is easy to discharge the foreign matters remaining in the gap between the inertial sensor and the circuit board by performing cleaning.

Ninth Aspect

In the sensor unit according to the first aspect, it is preferable that the inertial sensor is an acceleration sensor.

According to this aspect, since the sensor unit includes the acceleration sensor as the inertial sensor, the sensor unit can accurately detect acceleration.

Tenth Aspect

A vehicle positioning device according to this aspect includes: the sensor unit according to any one of the first to ninth aspects; a receiving section configured to receive a satellite signal superimposed with position information from a positioning satellite; an acquiring section configured to acquire the position information of the receiving section on the basis of the received satellite signal; a computing section configured to compute a posture of a vehicle on the basis of inertial data output from the sensor unit; and a calculating section configured to calculate a position of the vehicle by correcting the position information on the basis of the computed posture.

According to this aspect, it is possible to enjoy the effects of the sensor unit according to the invention. The vehicle positioning device having high measurement accuracy of inertia is obtained.

Eleventh Aspect

A portable electronic device according to this aspect includes: the sensor unit according to any one of the first to ninth aspects; a case in which the sensor unit is housed; a processing section housed in the case and configured to process output data from the sensor unit; a display section housed in the case; and a light transmissive cover closing an opening section of the case.

According to this aspect, it is possible to enjoy the effects of the sensor unit according to the invention. The portable electronic device having high measurement accuracy of inertia is obtained.

Twelfth Aspect

In the portable electronic device according to the eleventh aspect, it is preferable that the portable electronic device includes a satellite positioning system and measures a moving distance and a moving track of a user.

According to this aspect, convenience of the portable electronic device is improved.

Thirteenth Aspect

An electronic device according to this aspect includes: the sensor unit according to any one of the first to ninth aspects; and a control section configured to perform control on the basis of a detection signal output from the sensor unit.

According to this aspect, it is possible to enjoy the effects of the sensor unit according to the invention. The electronic device having high measurement accuracy of inertia is obtained.

Fourteenth Aspect

A vehicle according to this aspect includes: the sensor unit according to any one of the first to ninth aspects; and a control section configured to perform control on the basis of a detection signal output from the sensor unit.

According to this aspect, it is possible to enjoy the effects of the sensor unit according to the invention. The vehicle having high measurement accuracy of inertia is obtained.

Fifteenth Aspect

In the vehicle according to the fourteenth aspect, it is preferable that the vehicle includes at least any one system of an engine system, a brake system, and a keyless entry system, and the control section controls the system on the basis of the detection signal.

According to this aspect, it is possible to accurately control at least any one system of the engine system, the brake system, and the keyless entry system.

Sixteenth Aspect

A vehicle according to this aspect includes: the sensor unit according to any one of the first to ninth aspects; and a control section configured to control at least any one of acceleration, braking, and steering on the basis of a detection signal detected by the sensor unit. Whether automatic driving is carried out or not is switched according to a change of the detection signal output from the sensor unit.

According to this aspect, with the control section that controls at least any one of acceleration, braking, and steering, it is possible to accurately switch, according to a change of a detection signal detected by the sensor unit, whether the automatic driving is carried out or not.

Seventeenth Aspect

A display device according to this aspect includes: a display section worn on a head of a user and configured to irradiate image light on eyes of the user; and the sensor unit according to any one of the first to ninth aspects. The sensor unit is located further on one side than a center of the head in a mounted state of the display device.

According to this aspect, in the display device, the sensor unit is located further on one side than the center of the head in the mounted state. Therefore, when the head of the user moves, it is possible to quickly calculate a movement amount, a direction of the movement, and the like in a motion center. It is possible to enjoy the effects of the sensor unit according to the invention. The display device having high measurement accuracy of inertial is obtained.

The entire disclosure of Japanese Patent Application No. 2018-057651 filed Mar. 26, 2018 is expressly incorporated herein by reference.