Angular rate sensor having stacked rotors

Abstract

The invention relates to an angular rate sensor having a sensor substrate, a suspension element, a first rotor connected to the suspension element at least via a first spring element, and a second rotor connected to the sensor substrate at least via a second spring element, the sensor substrate having a main extension plane, and the suspension element being connected to the sensor substrate, characterized in that, starting from the sensor substrate and in a direction which points away from the sensor substrate and is perpendicular to the main extension plane, the first rotor is located downstream of the second rotor and / or is arranged in a stack together with the second rotor.

Description

[0001] R.412785

[0002] - 1 -

[0003] Description

[0004] title

[0005] Rotation rate sensor with stacked rotors

[0006] State of the art

[0007] The invention relates to a gyroscope with a first rotor and a second rotor and a sensor substrate according to the preamble of the main claim.

[0008] Modern micromechanical rotation rate sensor arrangements, see [reference].

[0009] DE102017216010A1 and DE102020205372A1 , have two rotor masses arranged in one plane, which are mechanically coupled via webs.

[0010] Disclosure of the invention

[0011] It is an object of the present invention to provide a gyroscope with a first rotor and a second rotor and a sensor substrate which has the following advantages.

[0012] The rotation rate sensor according to the invention, comprising a first rotor, a second rotor, and a sensor substrate, offers the advantage over the prior art that it requires only half the wafer area and is simultaneously robust against rotational acceleration, resulting in reduced costs and higher production throughput. Furthermore, the rotation rate sensor according to the invention allows for differential design of the detection electrodes, leading to reduced sensitivity drift compared to the prior art.

[0013] Advantageous embodiments and further developments of the invention can be found in the dependent claims and the description with reference to the drawings. R.412785

[0014] - 2 -

[0015] According to an advantageous embodiment of the invention, the angular rate sensor has a first rotor and a second rotor suspended on a common suspension, in particular on an armature, on a sensor substrate, in particular on a silicon substrate, via two similarly or identically designed spring elements.

[0016] According to an advantageous embodiment of the invention, it is provided that the first rotor has at least one first silicon layer and / or the second rotor has at least one second silicon layer, wherein the layer thickness of the first silicon layer and / or the layer thickness of the second silicon layer is in particular between 10 pm and 100 pm.

[0017] According to an advantageous embodiment of the invention, the distance between the first silicon layer of the first rotor and the second silicon layer of the second rotor is in the range of a few micrometers.

[0018] According to an advantageous embodiment of the invention, the spring elements are dimensioned such that the drive mode of the rotation rate sensor (namely the torsional vibration mode in the main extension plane of the rotors, in particular in the xy-plane) and the two detection modes (namely the tilting vibration modes along or about two orthogonal main extension axes in the main extension plane of the rotors, in particular along or about the x- or y-axis) are at a few tens of kHz and are as similar as possible for both rotors.

[0019] According to an advantageous embodiment of the invention, it is provided that a mechanical coupling of the otherwise independent eigenmodes of the first rotor and the second rotor of up to several kilohertz is achieved via a structure of the angular rate sensor with a common armature.

[0020] According to an advantageous embodiment of the invention, mechanical coupling with a common armature in the angular rate sensor generates a parallel and an antiparallel mode for each rotor mode, in which the individual rotors deflect in the same phase and out of phase, respectively. R.412785

[0021] - 3 -

[0022] According to an advantageous embodiment of the invention, it is provided that the antiparallel drive mode is excited, in particular to realize a rotational acceleration-robust gyroscope.

[0023] According to an advantageous embodiment of the invention, the gyroscope has detection electrodes, wherein the detection electrodes are designed such that a deflection of the antiparallel mode of a respective channel leads to a detection signal, while a deflection of the parallel mode does not provide a signal.

[0024] According to an advantageous embodiment of the invention, it is provided that at least one of the components of the gyroscope is located at a static electrical potential; in particular, at a static CM voltage.

[0025] According to an advantageous embodiment of the invention, the angular rate sensor is provided to have detection electrodes designed for differential detection.

[0026] According to an advantageous embodiment of the invention, it is provided that the detection electrodes of the gyroscope are integrated into the first rotor and / or the second rotor and / or are mounted on the first rotor and / or on the second rotor, wherein the integration and / or mounting is provided in such a way that a sensitivity drift is suppressed and / or eliminated.

[0027] According to an advantageous embodiment of the invention, the detection electrodes of the gyroscope are integrated into the sensor substrate and / or a cap wafer and / or attached to the sensor substrate and / or to the cap wafer, wherein the integration and / or attachment is provided in such a way that sensitivity drift is suppressed and / or eliminated and / or nullified.

[0028] According to an advantageous embodiment of the invention, it is provided that the first rotor and / or the second rotor has at least one detection mass, in particular one connected via at least one further spring element, preferably a U-spring, wherein the detection mass is designed and connected by means of the at least one further spring element R.412785

[0029] - 4 - is that a movement along a Coriolis force is possible, the Coriolis force occurring as a result of a rotation about an axis perpendicular to the principal extension plane in the co-rotating reference system.

[0030] According to an advantageous embodiment of the invention, it is provided that the first rotor and / or the second rotor has at least one detection mass, in particular one connected via at least one further spring element, preferably a U-spring, wherein the detection mass is designed and connected by means of the at least one further spring element in such a way that movement along a Coriolis force is possible, wherein the Coriolis force occurs as a result of a rotation about an axis perpendicular to the principal extension plane in the co-rotating reference system.

[0031] According to an advantageous embodiment of the invention, it is provided that at least one stator fixed to the sensor substrate is used for electrostatic detection, which is preferably read out differentially.

[0032] According to an advantageous embodiment of the invention, it is provided that the at least one stator fixed to the sensor substrate is designed to be continuous, which in particular makes it possible to measure both directions of movement.

[0033] According to an advantageous embodiment of the invention, the distance on both sides of the at least one stator fixed to the sensor substrate to a movable mass, wherein the movable mass is in particular at a static electrical potential, in particular by means of a CM voltage, is selected asymmetrically.

[0034] According to an advantageous embodiment of the invention, the first rotor and / or the second rotor has at least two, preferably four, detection masses, in particular connected via one or more further spring elements, preferably U-shaped spring elements, wherein the detection masses are designed and connected by means of the one or more further spring elements in such a way that movement along a Coriolis force is possible, wherein the Coriolis force occurs as a result of a rotation about an axis perpendicular to the principal plane of extension in the co-rotating reference frame. R.412785

[0035] - 5 -

[0036] According to an advantageous embodiment of the invention, it is provided that the at least one stator and the movable mass around the stator are designed to be round according to the radius of the rotor center.

[0037] Brief description of the drawings:

[0038] Figure 1a shows a schematic representation of a gyroscope according to the prior art.

[0039] Figure 1b shows a schematic representation of a gyroscope according to a first embodiment of the present invention in top and side views.

[0040] Figure 2a shows a schematic representation of a gyroscope rate sensor according to a second embodiment of the present invention and the drive mode of the gyroscope rate sensor in a top view.

[0041] Figure 2b shows a schematic representation of a gyroscope rate sensor according to a second embodiment of the present invention and the drive mode of the gyroscope rate sensor in a side view.

[0042] Figure 3a shows a schematic representation of a gyroscope rate sensor according to a third embodiment of the present invention and the parallel detection mode of the gyroscope rate sensor in a top view.

[0043] Figure 3b shows a schematic representation of a gyroscope rate sensor according to a third embodiment of the present invention and the antiphase vibration mode of the rotors as the detection mode of the gyroscope rate sensor in a side view.

[0044] Figure 3c shows a schematic representation of a gyroscope rate sensor according to a third embodiment of the present invention and the in-phase vibration mode of the gyroscope rate sensor in a side view.

[0045] Figure 4a shows a schematic representation of a gyroscope according to a fourth embodiment of the present invention and detection electrodes arranged on one of the rotors in a side view. R.412785

[0046] - 6 -

[0047] Figure 4b shows a schematic representation of a gyroscope according to a fifth embodiment of the present invention and detection electrodes located between a first and a second rotor in a side view.

[0048] Figure 4c shows a schematic representation of a gyroscope according to a sixth embodiment of the present invention and detection electrodes arranged on a sensor substrate and a cap wafer.

[0049] Figure 5a shows a schematic representation of a rotation rate sensor according to a seventh embodiment of the present invention and the movement of detection masses during a rotation about an axis of rotation oriented perpendicular to the main extension plane of the rotors.

[0050] Figure 5b shows a schematic representation of a rotation rate sensor according to an eighth embodiment of the present invention and two detection masses connected to the rotors via further spring elements and a stator for electrostatic detection of the movement of the detection masses.

[0051] Embodiments of the invention:

[0052] In the various figures, identical parts are always marked with the same reference symbols and are therefore usually only named or mentioned once.

[0053] Figure 1a shows a schematic representation of a gyroscope according to the prior art 90 with a double-rotor structure according to the prior art 91, a first spring element according to the prior art 93, a first rotor according to the prior art 94, a second spring element according to the prior art 95 and a second rotor according to the prior art 96. The gyroscope according to the prior art occupies a considerable area.

[0054] Figure 1b shows a schematic representation of a rotation rate sensor 100 according to the invention with a sensor substrate 102, with a rotor stack 110, a first spring element 103, a first rotor 104 of the rotor stack 110, an R.412785

[0055] - 7 - second spring element 105 and a second rotor 106 of the rotor stack 110 and with a main extension plane 11 of the first and second rotors and a suspension element 101 . The first rotor and the second rotor are connected to the suspension element via the first and second spring elements respectively.

[0056] Figure 2a shows a schematic representation of a gyroscope 100 comprising the first rotor 104, the first spring element 103, the second rotor 106, the second spring element 105, and the suspension element 101 according to a second embodiment of the present invention. The antiparallel drive mode of the gyroscope 100 is also shown schematically in a top view.

[0057] Figure 2b shows a schematic representation of a gyroscope 100 with a first rotor 104, a second rotor 106, a second spring element 105, and the suspension element 101 according to a second embodiment of the present invention. The antiparallel drive mode of the gyroscope 100 is also shown schematically in the side view.

[0058] Figure 3a shows a schematic representation of a gyroscope 100 according to a third embodiment of the present invention and a vibration mode of the gyroscope in a top view.

[0059] Figure 3b shows a schematic representation of a y-rate sensor 100 according to a third embodiment of the present invention and the antiphase vibration mode 111 of the rotors as the detection mode of the y-rate sensor 100 in a side view. As illustrated, an external rotation rate about the y-axis leads to a Coriolis force on the antiphase vibration mode 111. A rotational acceleration about the x-axis does not lead to a displacement of the antiphase vibration mode 111 via the Euler force. The same applies analogously to the x-channel.

[0060] Figure 3c shows a schematic representation of a y-rate sensor 100 according to a third embodiment of the present invention and the in-phase oscillation mode 112 of the y-rate sensor 100 in a side view. As illustrated, an external y-rate about the y-axis does not result in a Coriolis force on the in-phase oscillation mode. A rotational acceleration about the R.412785

[0061] - 8 - The x-axis, via Euler force, causes a displacement of the in-phase oscillation mode. The same principle applies analogously to the x-channel.

[0062] Figure 4a shows a schematic representation of a gyroscope 100 according to a fourth embodiment of the present invention and first detection electrodes 107 arranged on the second rotor 106 in a side view. The light gray structure is located on a static "CM" voltage, and the electrode surfaces marked "+" and "-" are used for differential detection. Unlike gyroscopes according to the prior art, the first detection electrodes 107 are not implemented in the sensor substrate 102 (dark gray), which suppresses sensitivity drift.

[0063] Figure 4b shows a schematic representation of a gyroscope 100 according to a fourth embodiment of the present invention and a side view of the second detection electrodes 108 arranged between the first rotor 104 and the second rotor 106. The light gray structure is applied to a static "CM" voltage, and the electrode surfaces marked "+" and "" are used for differential detection. Unlike gyroscopes according to the prior art, the detection electrodes 107 are not implemented in the sensor substrate 102 (dark gray), which suppresses sensitivity drift.

[0064] Figure 4c shows a schematic representation of a rotation rate sensor 100 according to a sixth embodiment of the present invention and third detection electrodes 109 arranged on a sensor substrate 102 and a cap wafer 119. With identical deformation of both electrode surfaces, the differential design leads to a cancellation of the sensitivity drift. A positive side effect of this design is that a linear acceleration along the axis oriented perpendicular to the main extension plane, which leads to a parabolic deflection of the rotors, also does not generate a capacitance signal to a first approximation.

[0065] Figure 5a shows a schematic representation of a rotation rate sensor 100 according to a seventh embodiment of the present invention and first directions of movement 113 of detection masses (see Fig. 5b) in the first rotor 104 and second directions of movement 114 of detection masses (see Fig. 5b) in the second rotor 106, each during a rotation about an axis of rotation oriented perpendicular to the main extension plane 11 of the rotors in the direction of rotation shown. R.412785

[0066] - 9 -

[0067] Figure 5b shows a schematic representation of a gyroscope 100 according to an eighth embodiment of the present invention and two detection masses 115, 116 connected to the rotors 104, 106 via further spring elements 120, and a first stator 117 and a second stator 118 for electrostatic detection of the movement of the detection masses 115, 116. For electrostatic detection, stators 117, 118 fixed to the sensor substrate 102 are typically used, which are read differentially (“+” and in the drawing). It is advantageous to arrange the stators 117, 118 as shown, so that a continuous stator 117, 118 can measure both directions of movement 113, 114. The distance on both sides of the stator 117, 118 to the moving mass with CM voltage is selected asymmetrically. This is shown for the lower of the two moving masses and would accordingly be mirrored for the upper one.Unlike the drawing, the stators 117, 118 and the moving masses around the stators 117, 118 would have to be round according to the radius of the rotor center, so that the capacity does not change during the drive deflection.

[0068] The invention is not limited to the embodiments described above, but can instead be used in a wide variety of applications for inertial sensor-based navigation, orientation, and stabilization of objects. A processing unit within the sensor can control the operation of the inertial sensor (e.g., power-saving mode, measuring ranges), validate sensor signals and check them for tolerances (e.g., for internal sensor monitoring), process signals (e.g., calculate position or orientation, filter data), and select communication protocols. Various algorithms, including self-learning AI-based ones, can be used in the processing unit for evaluating and processing the data from the inertial sensors, temperature sensors, and external data (e.g., GPS data, odometer data). Exemplary application areas can be found in:

[0069] - Automotive applications (e.g. ESP, Roll Over Sensing, Airbag, Road Noise Suppression, Anti-Theft Alarm System, Parking Bump Detection, Road Condition Monitoring),

[0070] - in two-wheeled applications such as motorcycles, bicycles, scooters (e.g. in ESP / AirBag, tilt detection, balancing),

[0071] - for three-wheeled vehicles such as tuk-tuks, R.412785

[0072] - 10 -

[0073] - in the avionics field (e.g. in flight stabilization and flight control),

[0074] - in industrial robot applications (e.g., position control of excavator buckets, drilling, image stabilization, flight control, alignment of satellite antennas, fine motor skills in robot gripping) - in applications for home and garden (e.g., navigation of lawnmowers, position monitoring of doors)

[0075] - in medical applications (e.g. fall detection, movement and posture tracking)

[0076] - in sports and leisure applications (e.g. motion detection, posture detection (in golf clubs, tennis rackets, skis), as well as in,

[0077] - numerous consumer applications, e.g., in smartphones, tablets, wearables, hearables, drones, gaming toys, AR or VR

[0078] Furthermore, numerous designs, changes, modifications, deviations, variations and embodiments are possible, all of which fall within the scope of the invention.

Claims

R.412785 - 11 - Claims 1. A gyroscope (100) comprising a sensor substrate (102), a suspension element (101), and a first rotor (104) connected to the suspension element (101) at least via a first spring element (103), and a second rotor (106) connected to the suspension element (101) at least via a second spring element (105), wherein the sensor substrate (102) has a principal extension plane (11) and a main surface running substantially parallel thereto, wherein the suspension element (101) is connected to the sensor substrate (102), characterized in that the first rotor (104) extends from the main surface of the sensor substrate (102) and in a direction parallel to the main surface of the sensor substrate. (102) is arranged in a forward direction perpendicular to the main extension plane (11) towards the second rotor (106) and / or is arranged on one side in a stack with the second rotor (106) on the main side of the sensor substrate (102).

2. Rotation rate sensor (100) according to claim 1, characterized in that via the suspension element (101) and / or via the first spring element (103) and / or via the second spring element (105) and / or via at least one additional spring element a mechanical coupling exists between the first rotor (104) and the second rotor (106).

3. Rotation rate sensor (100) according to one of the preceding claims, characterized in that the rotation rate sensor (100) has a first detection electrode (107), wherein the first detection electrode (107) is integrated into or located on the first rotor (104) and / or is integrated into or located on the second rotor (106).

4. Rotation rate sensor (100) according to one of the preceding claims, characterized in that the rotation rate sensor (100) has a second R.412785 - 12 - has a detection electrode (108), wherein the second detection electrode (108) is located between the first rotor (104) and the second rotor (106).

5. Rotation rate sensor (100) according to one of the preceding claims, characterized in that the rotation rate sensor (100) has a third detection electrode (109), wherein the third detection electrode is integrated in the sensor substrate (102) or is located on the sensor substrate (102) and / or is integrated in a cap wafer (119) or is located on the cap wafer (119).

6. Rotation rate sensor (100) according to one of the preceding claims, characterized in that the first rotor (104) and / or the second rotor (106) and / or the suspension element (101) are located at a static electrical potential.

7. Rotation rate sensor (100) according to one of the preceding claims, characterized in that the first rotor (104) and / or the second rotor (106) has at least one detection mass (115; 116), in particular one connected via a further spring element (120).

8. Rotation rate sensor (100) according to claim 7, characterized in that the at least one detection mass (115;116) can be excited to vibrations by Coriolis forces which occur as a result of a rotation about an axis perpendicular to the principal extension plane (11) in the co-rotating reference system.

9. Rotation rate sensor (100) according to one of claims 7 or 8, characterized in that the rotation rate sensor (100) has at least one stator (117; 118) connected to the sensor substrate (102), in particular a stator that is continuous.

10. Rotation rate sensor (100) according to claim 9, characterized in that the distance on both sides of the at least one stator (117; 118) to a movable mass is selected asymmetrically. R.412785 - 13 - 11. Rotation rate sensor (100) according to one of claims 9 or 10, characterized in that the at least one stator (117; 118) and the movable mass around the at least one stator (117; 118) are round according to the radius from the rotor center.

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