3-axis accelerometer

Abstract

Integrated single-mass three-axis accelerometer (400; 500) comprising: a single-mass xy ​​acceleration detection section (410; 510); and four single-mass rocker-type z-axis acceleration detection sections (420a...420d) embedded in the single-mass xy ​​acceleration detection section (410; 510), wherein the xy acceleration detection section (410; 510) extends in an xy-plane formed by the x-direction and y-direction and is movable in the xy-plane, wherein the rocker-type z-axis acceleration detection sections (420a...420d; 520a...520d) are each configured to rotate in a z-direction into and out of the xy-plane, wherein the x-direction, the y-direction and the z-direction are each pairwise perpendicular to each other, wherein the accelerometer (400; 500) in the xy-plane has the shape of a square and is symmetrical with respect to both perpendicular bisectors of the square as well as both diagonals of the square, and wherein the rocker z-axis acceleration detection sections (420a...420d; 520a...520d) are each coupled to the xy acceleration detection section (410; 510) by a z-holding device (426; 526).

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] The present application is a continuation claiming priority pursuant to 35 USC §120 of US Patent Application No. 16 / 138,091, filed on September 21, 2018, with attorney file number G0766.70249US00 and entitled “3-AXIS ACCELEROMETER”, which is incorporated herein in its entirety by reference. AREA OF REVELATION

[0002] The present application relates to inertial sensors with microelectromechanical systems (MEMS inertial sensors). BACKGROUND

[0003] Some inertial sensors using microelectromechanical systems (MEMS inertial sensors) are used to measure acceleration in one or more directions and are called accelerometers. These accelerometers generally use sample masses that are spring-coupled to a substrate and displaced in response to acceleration. Because of the spring couplings, the sample mass(s) often oscillate in response to the acceleration. The displacement and / or oscillation frequency of the sample mass(s) is measured using capacitive sensing techniques, resulting in an analog output signal representative of the displacement or oscillation. Some accelerometers, called resonant accelerometers, use actuators to oscillate the sample mass(s) at a predetermined frequency.In response to acceleration, the oscillation frequency of the test mass(s) changes. The frequency deviation from the predetermined drive frequency can be measured to determine the applied acceleration.

[0004] Some conventional three-axis accelerometers use individual sample masses for each detection direction. That is, a three-axis accelerometer employs three separate and mechanically independent sample masses, with one sample mass assigned to each direction. Typically, the lateral sample masses (e.g., x- and / or y-axis sample masses) are displaced and / or oscillate within a single plane. Vertical sample masses (e.g., the z-axis sample masses) are generally displaced into or out of the single plane and / or oscillate in this manner. SUMMARY OF THE REVELATION

[0005] A three-axis accelerometer contains a single integrated mass, which includes at least one laterally moving (xy) mass integrated with at least one vertically moving (z) mass. The vertically moving mass is configured as a teeter-totter mass located within the laterally moving mass. The vertically moving mass is mechanically coupled to the laterally moving mass by one or more torsion springs, and the laterally moving mass is mechanically coupled to one or more anchors or supports with one or more laterally moving fenders. The at least one laterally moving mass can be positioned symmetrically about one or more axes of the three-axis accelerometer, such that the three-axis accelerometer possesses plane symmetry.The three-axis accelerometer can provide several advantages, including being less sensitive to mechanical crosstalk or noise than alternative three-axis accelerometer designs and having a smaller footprint – occupying less chip area – than alternative three-axis accelerometer designs.

[0006] In some embodiments, an integrated single-mass three-axis accelerometer includes a single-mass xy ​​acceleration detection section and a single-mass rocker z-axis acceleration detection section embedded within the xy acceleration detection section.

[0007] In some embodiments, an integrated three-axis accelerometer comprises an anchor coupled to a substrate, a combined xy-acceleration detection sample mass, and first and second rocker-z-axis acceleration detection sample masses embedded within the xy-acceleration detection sample mass. The combined xy-acceleration detection sample mass is coupled to the anchor by a first tether, and the first and second rocker-z-acceleration detection sample masses are coupled to the xy-acceleration detection sample mass by a second and third tether, respectively.

[0008] In some embodiments, an integrated single-mass three-axis accelerometer comprises a single-mass xy-acceleration detection section and at least one single-mass rocker-axis z-acceleration detection section embedded within the single-mass xy-acceleration detection section. The accelerometer is symmetrical about both an x-axis and a y-axis. List of characters

[0009] Various aspects and embodiments of the application are described with reference to the following figures. It should be understood that the figures are not necessarily drawn to scale. Objects appearing in several figures are indicated in all figures in which they appear by the same reference numeral. Fig. Figure 1 is a top view of an embodiment of a three-axis accelerometer having a z-axis sample mass embedded in an xy-axis sample mass; Fig. Figure 2 is a top view of an embodiment of a three-axis accelerometer having two z-axis test masses embedded in an xy-axis test mass; Fig. 3 is a top view of a view of the Fig. 2 alternative embodiments representing a three-axis accelerometer comprising two z-axis test masses embedded in an xy-axis test mass; Fig. Figure 4 is a top view of an embodiment of a three-axis accelerometer having four z-axis test masses embedded in an xy-axis test mass; and Fig. 5 is a top view of a view of the Fig. 4 alternative embodiments, representing a three-axis accelerometer having four z-axis test masses embedded in an xy-axis test mass. Fig. 6 represents a motor vehicle which may contain at least one three-axis accelerometer according to a non-restrictive embodiment of the present application. DETAILED DESCRIPTION

[0010] The inventors recognized that conventional three-axis accelerometers with multiple independent sample masses for each sensing axis are too large and / or too expensive for many applications. Such three-axis accelerometers occupy a significant amount of space (chip footprint) because each sample mass requires its own sensing circuitry, as well as armatures and springs. Some three-axis accelerometers address this problem by using only a single solid sample mass to sensing acceleration in all three directions. However, the inventors recognized that such a design is highly susceptible to mechanical stress and / or mechanical crosstalk because the single solid sample mass is sometimes excited in any of the three sensing directions, regardless of the applied acceleration.This mechanical stress and / or mechanical crosstalk is undesirable, as it results in poor performance of the accelerometer.

[0011] To address this problem, some three-axis accelerometers utilize integrated sample masses with an xy-axis mass surrounded by a separate z-axis sample mass. However, the inventors recognized that these accelerometers have disadvantages, including low accuracy and a high z-axis offset error. A single z-axis sample mass as the outer mass is asymmetrical with respect to its axis of rotation, which can lead to mode crosstalk within the three-axis accelerometer. Furthermore, the inventors realized that such a configuration results in larger signal offset errors for the z-axis sample mass because it is necessarily positioned farther from the axis of rotation than it could be if the xy-axis mass were not located inside it.

[0012] In light of the foregoing, aspects of the present application provide an integrated three-axis accelerometer comprising an xy-axis sample mass with an embedded sample mass for detecting the z-axis acceleration. Such an arrangement can be implemented in a smaller footprint than alternative designs and can exhibit improved accuracy relative to conventional single-mass accelerometers due to reduced mechanical crosstalk and z-axis misalignment errors.

[0013] According to one aspect of the present application, an integrated single-mass three-axis accelerometer is provided. The accelerometer includes an xy-axis sample mass configured to move in a plane in the lateral directions (e.g., the x and y directions). The xy-axis sample mass includes an embedded mass configured to pivot out of the plane in a vertical direction (e.g., the z direction). In some embodiments, the embedded mass is a rocker mass configured to rotate into and out of the xy-plane. Since the embedded z-axis sample mass is integrated into the xy-axis sample mass, it also contributes to the xy-motion. Thus, the accelerometer can be described as a single-mass three-axis accelerometer.

[0014] According to another aspect of the present application, an integrated single-mass three-axis accelerometer includes a test mass configured to move in a plane in the x and y directions, with two or more embedded masses configured to move out of the plane in the z direction. The accelerometer may be symmetrical about one or more axes, such as symmetrical about the x and y axes (referred to here as "plane symmetry"). The symmetrical design may reduce the occurrence of mechanical crosstalk between the x, y, and z-axis modes and provide better offset performance.

[0015] According to yet another aspect of the present application, an integrated single-mass three-axis accelerometer comprises a single sample mass with an xy-acceleration detection section and a z-acceleration detection section embedded within the xy-acceleration detection section. The accelerometer can be symmetrical about both an x-axis and a y-axis, thus exhibiting plane symmetry.

[0016] As used here, an "xy-axis test mass" is one designed to move in the xy-plane. A "z-axis test mass" is one designed to move in the z-direction, for example, by rotating about the xy-plane.

[0017] Fig. Figure 1 depicts an embodiment of a three-axis accelerometer according to a non-restrictive embodiment of the present application. In this non-restrictive embodiment, the three-axis accelerometer comprises 100 An xy-axis sample mass with an embedded z-axis sample mass. The xy-axis sample mass is coupled to a fixed support, such as a substrate, and the embedded z-axis sample mass is coupled to the xy-axis sample mass. Referring to the figure, the three-axis accelerometer contains 100 an xy-axis test mass 110 and an embedded z-axis test mass 120, which form a first section 122 and a second section 124 (which are sometimes referred to as the positive and negative sections). The three-axis accelerometer 100 also contains a substrate 102 , anchor 104, xy-holding devices 112 and z-holding devices 126.

[0018] The substrate 102 It functions as a base for the accelerometer. That is, the substrate 102 can store the sample mass, and the sample mass can move relative to the substrate. 102 move the substrate 102 The substrate can be made of any suitable material, such as a semiconductor material (e.g., silicon). It can contain a drive and / or sensing circuit arrangement, such as electrodes, drive circuits, filter circuits, or any other circuit arrangement for operating the three-axis accelerometer. In some embodiments, the armatures represent 104 Extensions of the substrate 102 , such as that they are vertical columns of the substrate. However, alternatives are possible. For example, the anchors can 104In some embodiments, they may be formed from a separate material. The anchors themselves can be coupled to the xy-holding devices 112 to position the xy-axis sample mass (and indirectly the z-axis sample mass) above the substrate. 102 to hang up.

[0019] The xy-axis test mass 110 is designed to detect acceleration in the x and y directions. Specifically, the xy-axis test mass 110 is arranged to move laterally (in the x and y directions) in response to acceleration in these directions. The resulting movement of the xy-axis test mass 110 can be measured and used to calculate the acceleration in the x and / or y direction. The xy-holding devices 112 are arranged to secure the xy-axis test mass 110 with the anchors. 104The xy-axis holding devices 112 couple and allow movement of the xy-axis test mass 110 in the x and y directions. Additionally, the xy-holding devices 112 are rigid in the z direction to reduce or eliminate mechanical crosstalk of the xy-axis test mass 110. The xy-holding devices 112 provide a restoring force for the xy-axis test mass 110. In this non-restrictive example, the xy-holding devices 112 are designed as a spring that compresses in a first direction (e.g., the x-direction) and rotates in a second, in-plane direction (e.g., the y-direction). Other configurations of the holding devices 112 However, they are possible.

[0020] The xy-axis sample mass 110 can have various suitable shapes and dimensions and can be formed from any suitable material. In the non-limiting example shown, the xy-axis sample mass 110 is substantially rectangular and has a substantially rectangular outer circumferential surface. The dimensions of the xy-axis sample mass can be any suitable dimensions. For example, the sides of the outer circumferential surface of the xy-axis sample mass can each be in the range of 50–500 micrometers (including any values ​​within this range), or can be any other suitable values. The xy-axis sample mass can be formed from any suitable material, such as silicon. In some embodiments, the xy-axis sample mass 110 is formed by being formed from the substrate. 102etching is used, although alternative manufacturing processes are possible. In some embodiments, the xy-holding devices 112 are formed from the same material. For example, the xy-axis probe mass 110 and the xy-holding devices 112 can be formed from a common silicon layer of the substrate. 102 be etched.

[0021] The xy-axis test mass 110 may, in some embodiments, include drive / detection electrodes. For example, the movement of the xy-axis test mass 110 can be detected using comb fingers that can be positioned at any suitable location on the xy-axis test mass. For example, the fingers can be positioned in the areas defined by the boxes. 114 are delimited and can have any suitable configuration. The substrate 102The device may include appropriate drive / sensing electrodes. The electrodes can enable capacitive sensing of the movement of the xy-axis sample mass 110. If multiple comb drives are used, differential sensing can be employed, which can provide improved accuracy and precision of the accelerometer. Separate comb drives can be used for each of the x- and y-axes. In some embodiments, the drive electrodes can be used to oscillate the xy-axis and z-axis sample masses around their rest position at a predetermined frequency.

[0022] The z-axis test mass 120 is designed as a rocker mass with a first section 122 and a second 124, the sections of the z-axis test mass 120 represent separate sides of the rotation axis of the z-holding device 126. Accordingly, the z-axis test mass is designed to rotate into or out of the xy-plane. The first section 122 possesses a greater mass than the second section 124 This mass imbalance causes the z-axis test mass 120 to rotate in response to an applied z-axis acceleration. The z-holding devices 126 are designed as torsional springs that resist the rotation of the xy-axis test mass and return the z-axis test mass to a rest position. The z-holding devices 126 couple the z-axis test mass to the xy-axis test mass. Because the z-axis test mass 120 is only connected to the xy-axis test mass 110 and not directly to the substrate. 102Since the z-axis sample mass 120 is coupled, it moves in the xy-plane with the xy-axis sample mass 110 and can therefore be considered part of the xy-axis sample mass 110. The z-axis sample mass 120 is embedded within the xy-axis sample mass 110 because it moves with the xy-axis sample mass 110. Because the z-axis sample mass is embedded within the xy-axis sample mass, it contributes to the xy-axis sensing directions. However, the z-axis sample mass is decoupled from the xy-axis sample mass in the z-direction by the z-holding devices, so the xy-axis sample mass does not contribute to the sensing in the z-direction. Because the z-axis sample mass is embedded in the xy-axis sample mass, they can be considered to form a single sample mass, with the xy-axis sample mass representing one section of the single sample mass and the z-axis sample mass representing a second section of the sample mass.It should therefore be recognized that at least some aspects of the present application can be viewed as providing a single, integrated sample mass for detecting acceleration in three directions, and that the single, integrated sample mass may include an xy acceleration detection section and a z acceleration detection section.

[0023] The z-axis test mass 120 can contain electrodes that enable the detection / driving of its movement. For example, the first and second sections can 122 and 124 They may be doped so that they are conductive, or may contain conductive layers (e.g., metal layers), and may have a capacitance with structures (e.g., electrodes) on the substrate underlying the z-axis sample mass. 102 form. The capacities can enable capacitive detection and / or driving of the z-axis sample mass.

[0024] As in Fig. Figure 1 shows the three-axis accelerometer. 100 symmetrical about the x-axis. That is, on each side of the centerline AA' in the longitudinal direction parallel to the x-axis, the accelerometer has an equal mass distribution, which includes both the xy-axis test mass 110 and the z-axis test mass 120. According to the embodiment of Fig. 1 is the accelerometer 100The accelerometer is not symmetrical about the y-axis. Since the z-axis test mass is a rocker mass, it has an uneven weight distribution about the y-axis. Accordingly, the accelerometer has partial planar symmetry—symmetry about one of the x- and y-axes—but not complete planar symmetry (symmetry about both the x- and y-axes). In some embodiments, the substrate, the armatures, and the drive and / or sensing electrodes may have partial or complete planar symmetry or any other suitable arrangement, as the present disclosure is not so limited.

[0025] Variations of the holding devices 112are possible, which includes the number, positioning, orientation, shape, and material. In some embodiments, the xy-holding devices 112 can be designed as separate x-holding devices and y-holding devices. That is, the accelerometer 100The assembly may include both x-holding devices designed to allow the displacement of the xy-axis test mass 110 in the x-direction and y-holding devices designed to allow the displacement of the xy-axis test mass in the y-direction. The separate x- and y-holding devices may be any suitable spring designed to provide a restoring force for the xy-axis test mass. For example, possible x- and y-holding devices include, but are not limited to, compression springs, extension springs, and coil springs. The xy-holding devices 112 may be positioned at any suitable location and in any suitable orientation to assist the displacement of the xy-axis test mass in a predetermined direction and to provide a restoring force in the predetermined direction.Any suitable number of xy-holding devices, or x-holding devices and y-holding devices, can be provided to enable the desired movement of the xy-holding devices. Thus, the representation of four xy-holding devices in . Fig. 1 not restrictive.

[0026] Variations for the z-holding devices 126 are also possible. According to the in Fig. In the embodiment shown in Figure 1, the z-holding devices can be designed as torsion springs that provide a restoring force which returns the z-axis test mass 120 to a rest position when the z-axis test mass is rotated out of the xy-plane. The z-holding device can be any suitable torsion spring, since the present disclosure is not so restricted. Although in Fig. Where two z-holding devices 126 are shown, an alternative number may be provided. In some embodiments, the xy-holding devices and the z-holding devices may not be designed as springs, but may instead be any suitable bearing that suspends the xy-axis test mass and the z-axis test mass above the substrate and allows each of the masses to move.

[0027] In some embodiments, the thickness of a holding device can influence its sensitivity to unwanted mechanical crosstalk between one or more sensing directions. In particular, holding devices that are sufficiently rigid can prevent unwanted modes. That is, if the holding devices are sufficiently rigid, the mechanical crosstalk modes have a sufficiently high frequency so that they are not excited by typical operating conditions. In some embodiments, a holding device (e.g., the xy holding device and the z holding device) can have a suitable material thickness to reduce mechanical crosstalk. For example, a thickness (measured in the z-direction of Fig. 1) a holding device greater than 2 µm, 5 µm, 8 µm, 10 µm, 15 µm, 20 µm, 25 µm, 30 µm, between 2 and 35 µm, or any other suitable thickness. Accordingly, a holding device may have a thickness less than 35 µm, 28 µm, 23 µm, 18 µm, 13 µm, 9 µm, 7 µm, 4 µm, and / or any other suitable thickness. Combinations of the aforementioned ranges are envisaged, which, but are not limited to, include thicknesses between 25 and 35 µm, 10 and 23 µm, and between 5 and 13 µm. Of course, any suitable thickness of holding device can be used, since the present disclosure is not so restricted.

[0028] In some cases, the thickness of a holding device can correspond to a specific width of a holding device (measured in the xy-plane of Fig. 1) so that a holding device may have a desirable stiffness to reduce mechanical crosstalk. For example, the ratio between the thickness and width of a holding device may be greater than 0.5, 2, 4, 6, 8, 10, 15, 20, and / or any other suitable ratio. Correspondingly, the ratio between the thickness and width of a holding device may be less than 25, 20, 15, 10, 8, 6, 4, 1, and / or any other suitable ratio. Combinations of the aforementioned ranges are conceivable, including, but not limited to, ratios of 0.5 and 4, 10 and 25, and 6 and 15. Naturally, any suitable ratio between the thickness and width of a holding device may be employed, as the present disclosure is not so restricted.

[0029] Fig. Figure 2 represents another embodiment of a three-axis accelerometer200 ab, which is capable of differentially detecting the z-direction acceleration, which has an xy-axis test mass 210 and two z-axis test masses 220a, 220b, each of which has a first section 222a , 222b and a second section 224a , 224b The accelerometer also contains a substrate. 202 Anchors, 204, xy-holding devices 212 and z-holding devices 226. As the substrate 102 in the non-restrictive embodiment of Fig. 1. The substrate works 202 as a basis for the accelerometer and is connected to the anchors 204 directly connected. The substrate also functions as a stationary platform that can contain drive and sensing elements capable of moving and / or measuring the movement of the xy-mass and z-axis sample mass. The anchors 204are designed to connect to the xy holding devices 212 and to position the xy-axis sample mass (and indirectly the z-axis sample mass) above the substrate 202 to suspend. The xy-axis test mass is arranged to move in lateral directions (x and y directions), and this movement is measured and used to calculate the acceleration in the x and / or y direction. The xy holding devices 212 are arranged to suspend the xy-axis test mass with the anchors. 204 couple and provide a restoring force for the xy-axis test mass. In particular, the xy-holding devices are designed as a coil spring that compresses in a first direction (e.g., the y-direction) and rotates in a second, plane-internal direction (e.g., the x-direction). The embodiments of Fig. 2 differs from that of Fig. 1 in that the xy holding devices are oriented differently in the two embodiments, as shown. The z-axis test masses 220a, 220b are designed as rocker masses with the first sections 222a , 222b and the second sections 224a , 224b Designed accordingly, the z-axis test masses are arranged so that they move into or out of the xy-plane and thus move in the z-direction. The first sections 222a , 222b possess a greater mass than the second section 224a , 224b These mass imbalances cause the z-axis test masses to rotate in response to acceleration applied in the z-direction. The z-holding devices 226 are designed as torsional springs that resist the rotation of the xy-axis test mass and return the z-axis test masses to a rest position. The z-holding devices couple the z-axis test mass to the xy-axis test mass.

[0030] As in Fig. Figure 2 shows the two z-axis test masses 220a and 220b embedded in the xy-axis test mass 210. The two z-axis test masses are aligned with respect to the y-axis of the accelerometer. 200 Oppositely oriented. That is to say, the first sections 222a , 222b are equidistant from the y-axis, and the second sections 224a , 224b are similar and equidistant from the y-axis. According to the embodiment of Fig. 2. The two z-axis test masses are also arranged symmetrically around the x-axis of the accelerometer. Accordingly, the two z-axis test masses exhibit overall planar symmetry with the same mass distribution around both the x- and y-axes. That is, the two z-axis test masses are symmetrical with the same mass distribution on each side of the centerline BB' in the longitudinal direction and the centerline CC' in the transverse direction. Such an arrangement can reduce mechanical crosstalk and improve the accuracy of the accelerometer. According to the embodiment of Fig. 2. The outputs of the two z-axis sample masses 220a, 220b can be combined to generate a single output signal indicating the acceleration in the z-direction. For example, the difference between the two z-axis sample mass outputs (i.e., differential detection) can be used to reduce noise and offset errors associated with a single z-axis sample mass signal. Such an arrangement can improve the accuracy with respect to an accelerometer with a single z-axis sample mass. Of course, any suitable combination or processing of the two z-axis sample mass signals can be employed, as the present disclosure is not so limited.

[0031] According to the embodiment of Fig. The xy-axis test mass 210 surrounds the two z-axis test masses 220a and 220b and exhibits complete plane symmetry. This means that the xy-axis test mass has a uniform mass distribution with respect to the center line BB' in the longitudinal direction and the center line CC' in the transverse direction. Accordingly, the accelerometer 200 less sensitive to mechanical crosstalk. As in Fig. Figure 2 shows the xy-axis sample mass with the substrate 202 coupled by xy holding devices 212, which are designed as coil springs connected to the anchors 204 The accelerometers are coupled and attached to the substrate. The xy-holding devices and anchors are positioned symmetrically around both the x- and y-axes, so that the accelerometer exhibits complete plane symmetry.

[0032] Fig. 3 represents an alternative embodiment to that of Fig. 2 ab, which have a three-axis accelerometer 300 represents, which contains an xy-axis test mass 310 and two z-axis test masses 320a, 320b, each of which has a first section 322a , 322b and a second section 324a , 324b It contains the accelerometer. 300 also contains a substrate 302 Anchors, 304, xy-holding devices 312 and z-holding devices 326. Like the substrate 102 in the non-restrictive embodiment of Fig. 1. The substrate works 302 as a basis for the accelerometer and is connected to the anchors 304 directly connected. The substrate also functions as a stationary platform that can contain drive and sensing elements capable of moving and / or measuring the movement of xy-axis and z-axis sample masses. The anchors 304are designed to connect to the xy holding devices 312 and to position the xy-axis sample mass (and indirectly the z-axis sample mass) above the substrate 302 to suspend. The xy-axis test mass is arranged to move in lateral directions (x and y directions), and this movement is measured and used to calculate the acceleration in the x and / or y direction. The xy holding devices 312 are arranged to suspend the xy-axis test mass with the anchors. 304 couple and provide a restoring force for the xy-axis test mass. In particular, the xy-holding devices are designed as a coil spring that compresses in a first direction (e.g., the x-direction) and rotates in a second, plane-internal direction (e.g., the y-direction). The embodiments of Fig. 3 differs from that of Fig. 2 in that the xy holding devices are oriented differently in the two embodiments, as shown. The z-axis test masses 320a, 320b are designed as rocker masses with first sections 322a , 322b and second sections 324a , 324b Designed accordingly, the z-axis test masses are arranged so that they move into or out of the xy-plane and thus move in the z-direction. The first sections 322a , 322b possess a greater mass than the second section 324a , 324b These mass imbalances cause the z-axis test masses to rotate in response to acceleration applied in the z-direction. The z-holding devices 326 are designed as torsional springs that resist the rotation of the xy-axis test mass and return the z-axis test masses to a rest position. The z-holding devices couple the z-axis test mass to the xy-axis test mass.

[0033] As in Fig. Figure 3 shows the two z-axis test masses 320a, 320b being converted into the xy-axis test mass 310 in a similar manner to that shown in Figure 3. Fig. 2 embedded. The two z-axis test masses are relative to the y-axis of the accelerometer. 300 Oppositely oriented. That is to say, the first sections 322a , 322b are equidistant from the y-axis, and the second sections 324a , 324b are similar and equidistant from the y-axis. According to the embodiment of Fig. 2. The two z-axis test masses are also arranged symmetrically around the x-axis of the accelerometer. Accordingly, the two z-axis test masses exhibit complete plane symmetry with the same mass distribution on both sides of the centerline DD' in the longitudinal direction and the centerline EE' in the transverse direction. According to the embodiment of Fig. 3 and similar embodiments of Fig. 2. The outputs of the two z-axis test masses 320a, 320b can be combined to generate a single output signal that indicates the acceleration in the z-direction.

[0034] According to the embodiment of Fig. 3 surrounds the xy-axis test mass 310 and the two z-axis test masses 320a, 320b and exhibits complete plane symmetry, similar to the embodiment of Fig. 2. This means that the xy-axis test mass has a uniform mass distribution with respect to the centerline DD' in the longitudinal direction and the centerline EE' in the transverse direction. Accordingly, the accelerometer 300 less sensitive to mechanical crosstalk. As in Fig. Figure 3 shows the xy-axis sample mass with the substrate 302 coupled by xy holding devices 312, which are designed as coil springs connected to the anchors 304are coupled and attached to the substrate. The xy-holding devices and anchors are positioned symmetrically about both the x- and y-axes, so that the accelerometer has complete plane symmetry. In contrast to the embodiment of Fig. 2 are the xy holding devices 312 and anchors 304 perpendicular to the xy holding devices 212 of Fig. 2. Accordingly, the anchors are positioned further away from the center of the accelerometer, and the two z-axis test masses can occupy a larger relative area than the xy-axis test mass, resulting in greater mass. The z-axis test mass with the greater mass can utilize thicker mounting fixtures, which can reduce mechanical crosstalk by mitigating the effect of unwanted modes, as discussed above.

[0035] Fig. Figure 4 represents another embodiment of a three-axis accelerometer. 400 ab, which shows complete plane symmetry, containing an xy-axis test mass 410 and four z-axis test masses 420a, 420b, 420c, 420d, each of which has a first section 422a , 422b , 422c , 422d as well as a second section 424a , 424b , 424c , 424d The accelerometer also contains a substrate. 402 , anchor 404 , xy-holding devices 412, z-holding devices 426, finger 414 , positive electrodes 416a and negative electrodes 416b The xy-axis test mass 410 is arranged so that it shifts laterally (in the x and y directions). Each of the z-axis test masses 420a, 420b, 420c, 420d is arranged so that it rotates out of the plane relative to the xy-axis test mass. Each of the first sections 422a , 422b, 422c , 422d possesses more mass than any of the second sections. 424a , 424b , 424c , 424d , and as a result, the z-axis test masses will rotate when subjected to acceleration in the z-direction.

[0036] As in Fig. The anchors are shown in section 4. 404 on the substrate 402The xy-axis holding devices 410 are attached and arranged to be connected to the xy-holding devices 412. The xy-holding devices are designed as coil springs and suspend the xy-holding devices above the substrate, allowing the xy-axis test mass 410 to move in the x and y directions while providing a restoring force to return the xy-axis test mass to a rest position. The z-holding devices 426 are designed as torsion springs that suspend the z-axis test mass above the substrate and mechanically couple the xy-axis test mass to the z-axis test masses 420a, 420b, 420c, and 420d. The z-holding devices also provide a restoring force that returns each of the z-axis test masses to a rest position if the z-axis test masses are rotated out of the xy-plane. The fingers 414are coupled to the xy-axis probe mass, or in some embodiments represent a part of it, and move with the xy-axis probe mass when the xy-axis probe mass moves. The fingers are located between the positive electrodes. 416a and the negative electrodes 416b , which are attached to the substrate 402 are attached and can be used to adjust the distance between the fingers. 414 and the electrodes are arranged to measure. For example, the electrodes can be used to measure a capacitance between the fingers and the electrodes, which may correspond to a specific position of the xy-axis sample mass. The electrodes 416a , 416bThey can also be used to drive the xy-axis test mass at a specific frequency and to measure changes in frequency in order to detect acceleration. Of course, the electrodes and fingers can be used for any suitable function for measuring accelerations, as the present disclosure is not so limited.

[0037] According to the embodiment of Fig. 4 can have each of the four z-axis sample masses 420a, 420b, 420c, 420d corresponding electrodes (e.g., first and second electrodes, sometimes referred to as positive and negative electrodes) arranged on the substrate. The positive electrodes can be located near the first sections 422a , 422b , 422c , 422d the z-axis sample mass should be positioned, and the negative electrodes can be placed near the second sections. 424a , 424b , 424c , 424dThe electrodes can be positioned in either direction. They can detect the capacitances formed by the substrate and the z-axis probe masses. In some embodiments, the positive and negative electrodes can be used to drive the z-axis probe masses at a predetermined frequency and measure the change in frequency in response to an applied acceleration. In some embodiments, the signals from each of the z-axis probe masses can be combined as a differential signal or other combination to improve the accuracy of the accelerometer. For example, in the case of in-plane rotation, each of the z-axis probe masses on opposite sides would move in opposite directions in response to the rotation, which could be canceled out using differential signaling between the separate z-axis probe masses.According to this example, common-mode signals or noise would be canceled out by using a combination of differential signals.

[0038] As in Fig. As shown in section 4, the accelerometer has 400 a square shape. That is, the substrate 402 The substrate is square, and all components are arranged on and within its boundaries. Such an arrangement can further promote the reduction of noise and mechanical crosstalk between the x, y, and z directions. According to the embodiment of Fig. In this case, each component is oriented symmetrically about each of the x- and y-axes, so that the accelerometer exhibits complete plane symmetry. That is, the components are symmetrical with equal mass distribution on each side of the longitudinal centerline FF' and the transverse centerline GG'. In this case, the accelerometer also possesses square symmetry, which can further reduce its sensitivity to mechanical crosstalk. For example, as discussed above, the z-axis test masses can cancel common-mode noise because each mass on opposite sides or corners of the accelerometer can react in opposite directions to a disturbance such as in-plane rotation.

[0039] According to the in Fig. In the embodiment shown in Figure 4, the z-axis test masses 420a, 420b, 420c, 420d can be arranged such that the anchors 404Anchors can be positioned near the center. Anchors closer to the center of the substrate may be less susceptible to misalignment caused by thermal or mechanical stress on the substrate. That is, if the substrate is subject to warping, the center is less likely to warp significantly than the edges of the substrate. Accordingly, if the anchors are positioned within the z-axis sample masses with respect to the center, misalignment may be reduced or eliminated.

[0040] Fig. 5 forms one of the Fig. 4 alternative embodiment, which includes a three-axis accelerometer 500 represents an xy-axis test mass 410 and four z-axis test masses 520a, 520b, 520c, 520d, each of which has a first section 522a , 522b , 522c , 522d as well as a second section 524a , 524b , 524c, 524d The accelerometer also contains a substrate. 502 , anchor, 504, xy-holding devices 512 and z-holding devices 526. The xy-axis test mass 510 is arranged so that it shifts laterally (x and y directions). Each of the z-axis test masses 520a, 520b, 520c, 520d is arranged so that it rotates out of the plane with respect to the xy-axis test mass. Each of the first sections 522a , 522b , 522c , 522d possesses more mass than any of the second sections. 524a , 524b , 524c , 524d And as a result, the z-axis test masses will rotate when subjected to acceleration in the z-direction. The anchors 504 are attached to the substrate 502The xy-holding devices 512 are attached and arranged to be connected to the xy-holding devices 512. The xy-holding devices are designed as coil springs and suspend the xy-holding devices above the substrate, allowing the xy-axis test mass 510 to move in the x and y directions while providing a restoring force to return the xy-axis test mass to a rest position. The z-holding devices 526 are designed as torsion springs that suspend the z-axis test mass above the substrate and mechanically couple the xy-axis test mass to the z-axis test masses 520a, 520b, 520c, and 520d, and also provide a restoring force that returns the z-axis test mass to a rest position when rotated out of the xy-plane.

[0041] According to the in Fig. In the embodiment shown in section 5, the accelerometer can 500The accelerometer includes fingers positioned near the outer edges of the xy-axis sample mass 510 and coupled to it, allowing them to move with the sample mass. Positive and negative electrodes can be used to measure the position and / or frequency of the xy-axis sample mass fingers and the electrodes. Similarly, the accelerometer can include electrodes positioned on the substrate below the z-axis sample masses 520a, 520b, 520c, and 520d to detect the position and / or frequency of the z-axis sample masses.

[0042] As in Fig. As shown in section 5, this is the accelerometer. 500It is square and exhibits complete plane symmetry. That is, the components are symmetrical with equal mass distribution on each side of the centerline HH' in the longitudinal direction and the centerline II' in the transverse direction. Accordingly, the accelerometer can reject common-mode noise in response to specific accelerations (e.g., in-plane rotation) and be subject to reduced mechanical crosstalk, which can improve the accelerometer's accuracy, as discussed above.

[0043] According to the embodiment of Fig. 5. The z-axis test masses may have a larger—and in some cases a considerably larger—mass closer to the center of the accelerometer than towards the periphery. For example, as described above, the first sections 522a , 522b , 522c , 522d possess more mass than either of the second sections. 524a , 524b ,524c , 524d . Such a configuration can support the use of thicker springs with the z-axis test masses 520a, 520b, 520c, 520d, the use of which can further reduce mechanical crosstalk.

[0044] Some applications of some embodiments of the present application include low- or high-acceleration environments, which include, but are not limited to, automotive engineering, wearable devices and machine-based health monitoring. Fig. Figure 6 presents a non-restrictive example in which a three-axis accelerometer of the type described here is used in a motor vehicle. In the example of Fig. 6 contains a motor vehicle 600 a control unit 601 , which are equipped with an on-board computer 604 the vehicle is connected via a wired or wireless connection. The control unit 601The vehicle may contain at least one three-axis accelerometer of the types described herein. As a non-restrictive example, the at least one three-axis accelerometer may detect acceleration in the direction of travel and / or perpendicular to the direction of travel. The at least one three-axis accelerometer may also be configured to detect vertical accelerations, which may be useful, for example, to monitor the status of a vehicle's wheel suspension. 600 to monitor the control unit 601 can receive power and control signals from the on-board computer 604 received and can be sent to the on-board computer 604 Supply output signals of the type described here.

[0045] Reduced mechanical crosstalk in a single-mass accelerometer can be achieved in a package much smaller than conventional offerings, which may be desirable in some applications. In some embodiments, an accelerometer can have a chip area larger than 0.5 mm². 2 , 0.75 mm 2 , 1 mm 2 , 1.25 mm 2 , 1.5 mm 2 , 1.75 mm 2 , 2 mm 2 , 2.5 mm 2 , 3 mm 2 or any other suitable surface. Accordingly, an accelerometer can be smaller than 3.5 mm. 2 , 2.75 mm 2 , 2.25 mm 2 , 2 mm 2 , 1.75 mm 2 , 1.5 mm 2 , 1.25 mm 2 , 1 mm 2 , 0.75 mm 2 and / or any other suitable surface. Combinations of the aforementioned areas are envisaged, which, but are not limited to, include both 0.5 and 1.75 mm. 2, 1 and 2.25 mm 2 as well as 1.5 and 3.5 mm 2 included. Of course, any suitable area can be used, since the present disclosure is not so restricted.

[0046] Although the present teachings have been described in connection with various embodiments and examples, it is not intended that the present teachings are limited to such embodiments or examples. On the contrary, the present teachings include various alternatives, modifications, and equivalents, as will be recognized by those skilled in the art. Accordingly, the foregoing description and the drawings are only exemplary.

[0047] The terms "approximately" and "about" may be used to mean within ±20% of a target value in some embodiments, within ±10% of a target value in some embodiments, within ±5% of a target value in some embodiments, and even within ±2% of a target value in some embodiments. The terms "approximately" and "about" may include the target value. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 16 / 138091

[0001]

Claims

[1] Integrated single-mass three-axis accelerometer comprising: an xy acceleration detection section of the individual mass; and a rocker-z-axis acceleration detection section of the individual mass, which is embedded in the xy-acceleration detection section. [2] Integrated single-mass three-axis accelerometer according to claim 1, wherein the xy acceleration detection section is coupled to a substrate by an anchor and the z-axis acceleration detection section is coupled to the xy acceleration detection section by a holding device. [3] Integrated single-mass three-axis accelerometer according to claim 2, wherein the z-axis acceleration detection section is not directly coupled to the substrate or the armature. [4] Integrated single-mass three-axis accelerometer according to claim 2, wherein the holding device is a torsion holding device. [5] Integrated single-mass three-axis accelerometer according to claim 1, wherein the integrated single-mass three-axis accelerometer is symmetrical about an x-axis and / or a y-axis of the integrated single-mass three-axis accelerometer. [6] Integrated single-mass three-axis accelerometer according to claim 1, wherein the rocker z-axis acceleration detection section is a first rocker z-axis acceleration detection section and wherein the integrated single-mass three-axis accelerometer further comprises a second rocker z-axis acceleration detection section embedded in the xy acceleration detection section. [7] Integrated single-mass three-axis accelerometer according to claim 6, wherein the first rocker z-axis acceleration detection section and the second rocker z-axis acceleration detection section are arranged opposite each other about an x-axis and / or a y-axis of the integrated single-mass three-axis accelerometer. [8] Integrated three-axis accelerometer comprising: an anchor that is coupled to a substrate; a combined xy-acceleration detection sample mass, wherein the combined xy-acceleration detection sample mass is coupled to the armature by a first holding device; and first and second rocker z-axis acceleration detection sample masses embedded in the xy acceleration detection sample mass, wherein the first and second rocker z-axis acceleration detection sample masses are coupled to the xy acceleration detection sample mass by a second holding device and a third holding device, respectively. [9] Integrated three-axis accelerometer according to claim 8, further comprising third and fourth rocker z-axis acceleration detection sample masses embedded in the xy acceleration detection sample mass. [10] Integrated three-axis accelerometer according to claim 8, wherein the integrated three-axis accelerometer is symmetrical about an x-axis and / or a y-axis of the integrated three-axis accelerometer. [11] Integrated three-axis accelerometer according to claim 10, wherein the integrated three-axis accelerometer is symmetrical about both the x-axis and the y-axis of the integrated three-axis accelerometer. [12] Integrated three-axis accelerometer according to claim 8, wherein the first holding device is a two-axis jump holding device. [13] Integrated three-axis accelerometer according to claim 12, wherein the second holding device is a torsion holding device. [14] Integrated three-axis accelerometer according to claim 8, wherein the first and second rocker z-axis acceleration detection sample masses are not directly coupled to either the anchor or the substrate. [15] Integrated single-mass three-axis accelerometer comprising: an xy acceleration detection section of the individual mass; and at least one rocker-z-axis acceleration detection section of the individual mass embedded in the xy-acceleration detection section, wherein the accelerometer is symmetric about both an x-axis and a y-axis of the accelerometer. [16] Integrated single-mass three-axis accelerometer according to claim 15, wherein the at least one rocker z-axis acceleration detection section comprises two rocker z-axis acceleration detection sections. [17] Integrated single-mass three-axis accelerometer according to claim 16, wherein the two rocker z-axis acceleration detection sections are arranged completely opposite each other around the x-axis and / or the y-axis of the integrated single-mass three-axis accelerometer. [18] Integrated single-mass three-axis accelerometer according to claim 15, wherein the at least one rocker z-axis acceleration detection section comprises four rocker z-axis acceleration detection sections. [19] Integrated single-mass three-axis accelerometer according to claim 18, wherein each of the four rocker z-axis acceleration detection sections is arranged completely in a respective quadrant of the accelerometer as defined by the x-axis and the y-axis of the integrated single-mass three-axis accelerometer. [20] Integrated single-mass three-axis accelerometer according to claim 15, wherein the xy detection section is coupled to a substrate by an anchor, wherein the at least one rocker z-axis acceleration detection section is coupled to the xy detection section by a holding device, and wherein the at least one rocker z-axis acceleration detection section is not directly coupled to either the substrate or the anchor.